PAPERMAKING BELT

Abstract

Provided is a papermaking belt that is used in a papermaking machine and that comprises a first plane on which a wet paper web is placed and a second plane on the opposite side to the first plane, wherein the papermaking belt comprises a reinforcing fibrous substrate layer comprising at least one layer of a woven fabric, at least one layer of said woven fabric comprises a double or more combination weave pattern, said combination weave pattern comprises first yarns and second yarns that are placed in parallel; said first yarns are placed closer to the first plane-side than said second yarns and said second yarns are placed closer to the second plane-side than said first yarns; and said second yarns comprise a polyester yarn.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims benefit of priority from Japanese Patent Application No. 2022-138603, filed on Aug. 31, 2022, the entire contents of which are incorporated herein by reference.

BACKGROUND

Technical Field

The present disclosure relates to a papermaking belt.

Background Art

A papermaking machine for removing moisture from a source material of paper is generally equipped with a wire part, a press part, and a dryer part. These parts are placed in the order of the wire part, the press part, and the dryer part in a wet paper web transfer direction.

In each part of such a papermaking machine, various papermaking belts are used for the purpose of transferring and compressing a wet paper web, etc. Such papermaking belts include such as, for example, a wet paper transfer belt (transfer belt) for transferring and delivering a wet paper web, and a shoe press belt used in a shoe press mechanism.

Regarding the delivery of a wet paper web using a wet paper transfer belt in the press part, as a papermaking machine, a closed-draw papermaking machine that delivers a wet paper web in the closed-draw manner is currently known. In a press part of the closed-draw papermaking machine, the wet paper web is transferred while being mounted on a papermaking felt or wet paper transfer belt. Thus, the wet paper web never run alone, preventing the generation of paper breaking. Therefore, the closed-draw papermaking machine exhibits an excellent high speed running suitability and operation stability.

WO 03/071030 A1 proposes, for the purposes of preventing warping at the end part that is caused by the different shrinkage properties and finishing steps, etc., of different materials, a papermaking belt having two layers consisting of resin materials, of which one layer is placed on the cd supporting layer side and the other layer is placed on the front side.

SUMMARY

Technical Problem

Incidentally, a papermaking belt may be used with an automatic guiding apparatus, so-called a “guider”, in order to prevent meandering of the papermaking belt. The guider generally detects an end part in the width direction of the running papermaking belt, and adjusts the running position of the papermaking belt. Here, if there is warping at the end position of the papermaking belt, the guider cannot detect the precise position of the papermaking belt, and it becomes incapable of appropriately adjusting the running position of the papermaking belt. As a result, it becomes difficult that the papermaking belt is stably used.

Moreover, a papermaking belt is generally used in presence of water, i.e., in a wet state.

Therefore, conditions under which warping is developed at the end part of the papermaking belt need to be considered taking the wet state into account. The papermaking belt described in WO 03/071030 A1 is merely aimed at preventing warping at the end part of the papermaking belt, but it does not consider the warping at the end part in a wet state.

Accordingly, an object of the present disclosure is to provide a papermaking belt whose warping at the end part during its use has been suppressed.

Solution to Problem

The present inventor has made an intensive investigation in order to achieve the above-described object, and as a result, found that a base fabric layer that constitutes the papermaking belt has a relatively large influence on the warping at the end part of the papermaking belt when being used. Furthermore, the present inventors have found that the warping at the end part of the papermaking belt could be suppressed by employing a woven fabric having a combination weave pattern in a base fabric layer and carefully selecting the materials for the yarns of the combination weave pattern. The present inventor has further proceeded the investigation and as a result accomplished the present invention.

A gist of the present invention is as follows:

[1] A papermaking belt that is used in a papermaking machine and that comprises a first plane on which a wet paper web is placed and a second plane on the opposite side to the first plane, wherein:

• • the papermaking belt comprises a reinforcing fibrous substrate layer comprising at least one layer of a woven fabric;
  • at least one layer of said woven fabric comprises a double or more combination weave pattern;
  • said combination weave pattern comprises first yarns and second yarns that are placed in parallel;
  • said first yarns are placed closer to the first plane-side than said second yarns and said second yarns are placed closer to the second plane-side than said first yarns; and
  • said second yarns comprise a polyester yarn.[2] The papermaking belt according to [1], wherein said second yarns are crimped yarns.[3] The papermaking belt according to [1] or [2], wherein said second yarns are multifilament twist yarns.[4] The papermaking belt according to any one of [1] to [3], wherein said first yarns and said second yarns are placed in the machine direction of the papermaking belt.[5] The papermaking belt according to any one of [1] to [4], comprising no batt fiber layer.[6] The papermaking belt according to any one of [1] to [5], wherein the fineness of said first yarns are greater than the fineness of said second yarns.[7] The papermaking belt according to any one of [1] to [6], wherein:
  • said woven fabric further comprises third yarns that are woven into said first yarns and said second yarns; and
  • said third yarns are monofilament twist yarns.[8] The papermaking belt according to any one of [1] to [7], wherein:
  • said woven fabric comprising said combination weave pattern further comprise third yarns that are woven into said first yarns and said second yarns; and
  • said combination weave pattern is a weave pattern that comprises a repeat unit that is capable of concurrent formation of a repeat in which each said third yarn passes through K said first yarns on the side of said first plane while it passes through L said first yarns on the side of said second plane and a repeat in which each said third yarn passes through M said second yarns on the side of said first plane while it passes through N said second yarns on the side of said second plane;
  • wherein the relation K/L N/M is satisfied.[9] The papermaking belt according to any one of [1] to [8], wherein:
  • said woven fabric comprising said combination weave pattern further comprises third yarns that are woven into said first yarns and said second yarns, and
  • the number of crossing points of said first yarns and said third yarns in a weave repeat is greater than the number of crossing points of said second yarns and said third yarns in the weave repeat.[10] The papermaking belt according to any one of [1] to [9], wherein the papermaking belt is a wet paper transfer belt.[11] The papermaking belt according to any one of [1] to [9], wherein the papermaking belt is a shoe press belt.

Advantageous Effects of Invention

By the above-mentioned configuration, it is possible to provide a papermaking belt whose warping at the end part during its use has been suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view in a cross machine direction showing an example of a papermaking belt according to a preferred embodiment of the present disclosure.

FIG. 2 is an enlarged cross-sectional view of a reinforcing fibrous substrate provided in a papermaking belt according to a preferred embodiment of the present disclosure.

FIG. 3 is a diagram of a weave repeat of a woven fabric of a reinforcing fibrous substrate provided in a papermaking belt according to a preferred embodiment of the present disclosure.

FIG. 4 is a diagram of a weave repeat of a woven fabric of a reinforcing fibrous substrate provided in a papermaking belt according to a preferred embodiment of the present disclosure.

FIG. 5 is an enlarged cross-sectional view of a reinforcing fibrous substrate provided in a papermaking belt according to a modified example of the present disclosure.

FIG. 6 is a diagram of a weave repeat of a woven fabric of a reinforcing fibrous substrate provided in a papermaking belt according to a modified example of the present disclosure.

FIG. 7 is a diagram of a weave repeat of a woven fabric of a reinforcing fibrous substrate provided in a papermaking belt according to a modified example of the present disclosure.

FIG. 8 is a cross-sectional view in a cross machine direction of a papermaking belt according to another modified example of the present disclosure.

FIG. 9 is a schematic diagram for illustrating a preferred embodiment of a method of producing a papermaking belt according to the present disclosure.

FIG. 10 is a schematic diagram for illustrating a preferred embodiment of a method of producing a papermaking belt according to the present disclosure.

FIG. 11 is a schematic diagram for illustrating another preferred embodiment of a method of producing a papermaking belt according to the present disclosure.

FIG. 12 is a schematic diagram for illustrating another preferred embodiment of a method of producing a papermaking belt according to the present disclosure.

FIG. 13 is a schematic diagram for illustrating a method for evaluating the warping at the end part of the wet paper transfer belt used in examples.

FIG. 14 is a schematic diagram for illustrating a method for evaluating the warping at the end part of the wet paper transfer belt used in examples.

FIG. 15 is an overview showing an example of a papermaking belt and an automatic guiding apparatus loaded on a papermaking machine.

FIG. 16 is an overview illustrating the relationship between the warping at the end part of a papermaking belt and a detection part (a palm) of an automatic guiding apparatus.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, referring to the appended drawings, preferred embodiments of a papermaking belt according to the present disclosure will be described in detail.

1. RELATIONSHIP BETWEEN PAPERMAKING BELT AND AUTOMATIC GUIDING APPARATUS

First, prior to the description of a papermaking belt according to the present disclosure, the relationship between a papermaking belt and an automatic guiding apparatus is to be explained.

FIG. 15 is an overview showing an example of a papermaking belt and an automatic guiding apparatus loaded on a papermaking machine, FIG. 16 is an overview illustrating the relationship between the warping at the end part of a papermaking belt and a detection part (palm) of the automatic guiding apparatus.

A papermaking belt 101 shown in FIG. 15 is an endless belt that runs via a roll. An automatic guiding apparatus 110 is an apparatus that adjusts the running position of the papermaking belt 101 such that the running position of the papermaking belt 101 will not lean towards either drive-side or non-drive-side of the papermaking machine during the operation. The automatic guiding apparatus 110 regularly detects the position of the papermaking belt 101 and at the same changes the angle of a guide roll 102 against the running direction of the papermaking belt 101, thereby adjusting the running position of the papermaking belt 101 so that the papermaking belt 101 will be in an adequate position.

For controlling the angle of the guide roll 102, a structure is generally used in which an end part of an actuator 106 such as an air spring is connected to a bearing on one side of the guide roll 102, and at the same time, a coil spring 107 is installed in order to balance the actuator 106 with the coil spring 107. By adding a pneumatic pressure to the actuator 106, a bearing 108 on one side moves using a bearing 109 on the side of the other end as a fulcrum. Then, the position of the guide roll 102 (the angle of the papermaking belt 101 against the running direction) is determined such that the force by which the actuator 106 pushes the bearing 108 is in equilibrium with the reaction force by the coil spring 107.

Moreover, a pneumatic pressure adjusting apparatus 104 provided with a palm-type position detector is often used as an apparatus for detecting the position of the papermaking belt 101 and supplying pneumatic pressure corresponding to that position to the actuator 106 of the guide roll 102. A constant pneumatic pressure (supply pressure) is supplied to the pneumatic pressure adjusting apparatus 104 through a pressure reducing valve 105, while a palm 103 is brought into contact with an end part of the running papermaking belt 101. Then, a change in the position of an end part 1011 of the papermaking belt 101 is detected as a displacement of the palm 103 that is brought into in contact, and, by means of this displacement of the palm 103, a part of or whole supply air inside the pneumatic pressure adjusting apparatus 104 is released into atmosphere, leaving a residual pressure as an output pressure of the pneumatic pressure adjusting apparatus 104. By supplying the air of this output pressure to the actuator 106, the position of the guide roll 102 can be adjusted.

Here, the relationship between the palm 103 and the end part 1011 of the papermaking belt 101 is to be examined. As shown in FIG. 16, when there is no warping in the papermaking belt 101 (a papermaking belt 101′), the end part 1011′ of the papermaking belt 101′ will be in contact with the palm 103 in an appropriate position, and the automatic guiding apparatus 110 is capable of detecting an exact position of the papermaking belt 101′. On the other hand, when there is warping in the end part 1011 of the papermaking belt 101, because the end part 1011 will be located at a distance D from the position where it should originally be detected as a result of the warping of the end part 1011, problems may occur, such as that the palm 103 becomes incapable of being in contract with the end part 1011, that the palm 103 is brought into contact with the end part 1011 in a position away from where they should be in contact, and that the contact occurs in a part other than the palm 103 of the automatic guiding apparatus 110.

Accordingly, when there is warping in the papermaking belt 101, it becomes difficult to stably use the papermaking belt 101, because the automatic guiding apparatus 110 cannot detect the exact position of the papermaking belt 101. In the description above, problems that may occur due to warping of a papermaking belt have been explained with reference to as an example a palm-type automatic guiding apparatus that uses a palm as an automatic guiding apparatus, though similar problems may occur in other mechanical automatic guiding apparatuses or optical automatic guiding apparatuses, which also detect the end part of the papermaking belt to adjust the position of the papermaking belt.

In view of such circumstance, the present inventor has developed a papermaking belt as described below, in which the warping at its end part during use is suppressed.

2. WET PAPER TRANSFER BELT (PAPERMAKING BELT)

Next, a papermaking belt according to a preferred embodiment of the present disclosure will be described.

FIG. 1 is a cross-sectional view in a cross machine direction showing an example of a wet paper transfer belt (papermaking belt) according to a preferred embodiment of the present disclosure, FIG. 2 is an enlarged cross-sectional view of the reinforcing fibrous substrate provided in the wet paper transfer belt shown in FIG. 1, and FIGS. 3 and 4 are diagrams of weave repeats of a woven fabric of the reinforcing fibrous substrate provided in the wet paper transfer belt shown in FIG. 1. Note that, in the drawings, each member has been emphasized in size as appropriate for ease of illustration and thus does not indicate the actual proportion and size of each member. Herein, the aforementioned cross machine direction may be referred to as “CMD”, and the machine direction may be referred to as “MD”. Also note that, in the present embodiment, a wet paper transfer belt is to be described as an example of a papermaking belt, though the papermaking belt of the present invention is not to be limited thereto.

The wet paper transfer belt (papermaking belt) 1 shown in FIG. 1 is to be used for transferring and delivering a wet paper web W in a press part of the papermaking machine. The wet paper transfer belt 1 forms an endless band-shaped body. That is, the wet paper transfer belt 1 is an annular belt. Moreover, the wet paper transfer belt 1 is normally placed such that its circumferential direction runs along the machine direction (MD) of the papermaking system.

The wet paper transfer belt 1 comprises a reinforcing fibrous substrate layer 11, a first resin layer (a wet paper web carrying-side resin layer) 13 placed on one principal plane (a first plane 131) on the outer surface-side of the reinforcing fibrous substrate layer 11, and a second resin layer (a roll-side resin layer) 15 placed on the other principal plane (a second plane 151) on the inner surface-side of the reinforcing fibrous substrate layer 11, and these layers are laminated to form the wet paper transfer belt 1. Moreover, the first resin layer 13 is a layer that forms the outer surface of an annulus that is formed by the wet paper transfer belt 1.

The reinforcing fibrous substrate layer 11 comprises a reinforcing fibrous substrate 111 and a resin 113. The resin 113 is present as a matrix resin in the reinforcing fibrous substrate layer 11 such that it fills the interspace between fibers in the reinforcing fibrous substrate 111. That is, a part of the resin 113 is impregnated in the reinforcing fibrous substrate 111, whereas the reinforcing fibrous substrate 111 is embedded in the resin 113.

The reinforcing fibrous substrate 111 in the present embodiment is a woven fabric having a double weave pattern comprising first warp yarns 115, second warp yarns 117, and weft yarns 119. In the double weave pattern of the reinforcing fibrous substrate 111, the first warp yarns 115 are placed on the first plane 131-side (the wet paper web carrying-side), whereas the second warp yarns 117 are placed on the opposite side to the first plane 131-side, i.e., the second plane 151-side (the roll-side). Moreover, the first warp yarns 115 and the second warp yarns 117 are placed in parallel. Furthermore, the first warp yarns 115 and the second warp yarns 117 are, in FIGS. 1 and 2, placed in the direction that is perpendicular to the paper face, i.e., along the machine direction (MD). On the other hand, the weft yarns 119 are placed approximately perpendicular to the first warp yarns 115 and the second warp yarns 117, i.e., along the cross machine direction (CMD). The weft yarns 119 are woven into the first warp yarns 115 and the second warp yarns 117.

Note that, in FIGS. 1 and 2, in order to facilitate understanding, a part of the structure of the reinforcing fibrous substrate 111 is schematically described.

Herein, a “warp yarn” is a yarn that is placed along the machine direction (MD) of a wet paper transfer belt (papermaking belt), i.e., in the circumferential direction, whereas a “weft yarn” is a yarn that is placed along the cross machine direction (CMD) of the wet paper transfer belt (papermaking belt), i.e., in the direction that is perpendicular to the circumferential direction and parallel to the first plane of the papermaking belt. In other words, the direction of a warp yarn is set on the basis of the machine direction in a papermaking belt and a papermaking machine, i.e., a wet paper web transfer direction, the direction of a weft yarn is set on the basis of the cross machine direction in a papermaking belt and a papermaking machine, i.e., a direction that is perpendicular to the wet paper web transfer direction. Also, the warp yarn may not be in parallel with the machine direction (MD) of the papermaking belt, and it may be placed, for example, such that it has an angle within ±10° against the machine direction (MD) of the papermaking belt. Also, the weft yarn may not be in parallel with the cross machine direction (CMD) of a papermaking belt, and it may be placed, for example, such that it has an angle of within ±10° against the cross machine direction (CMD) of a papermaking belt.

Furthermore, in the present embodiment, the second warp yarns 117 comprises a polyester yarn. By this, it is possible to suppress the warping of the wet paper transfer belt 1 at its end part, i.e., the end part in the cross machine direction (CMD), during its use.

For further details, the present inventor has found that, regarding the warping of a wet paper transfer belt at its end part during its use, there is not only an early stage warping in the finished product just after the production, but also a warping developed by getting wet with water, etc. during use and by a mechanical action in the papermaking machine. Furthermore, the present inventor has focused on a possibility that, above all, the warping developed by swelling of the wet paper transfer belt with water, etc. during use may cause the greatest influence among the warping at the end part of the papermaking belt.

Then, the present inventor has found that it is possible to control warping of a wet paper transfer belt at its end part by employing a woven fabric having a combination weave pattern in a reinforcing fibrous substrate, and further including a polyester yarn in second yarns of the two parallel yarns in the woven fabric on the opposite side to the wet paper web carrying-side (i.e., the roll-side). Specifically, first, a papermaking belt is in the presence of a large amount of water during its use. On the other hand, a polyester yarn is a material that is relatively less easy to absorb water. Therefore, in a reinforcing fibrous substrate provided with a woven fabric comprising such second yarns, the warping of its end part towards the wet paper web carrying-side will be suppressed, because the second yarns on the roll-side does not absorb water and thus does not swell during the use of the papermaking belt. As results, the warping at the end part of a wet paper transfer belt during its use, in particular the warping towards the wet paper web carrying-side, is suppressed. Note that, in the present embodiment, the first warp yarns 115 are used as the first yarns and the second warp yarns 117 are the second yarns.

As mentioned above, in the present embodiment, the second warp yarns 117 comprises a polyester yarn. A polyester yarn is a yarn that comprise at least a polyester resin. The polyester resin has a low water absorbency, and its swelling due to water absorption is suppressed under the operating environment of a papermaking belt, such as the wet paper transfer belt 1, where a large amount of water is used. Therefore, the swelling of the second warp yarns 117 due to water absorption is suppressed during the use of the wet paper transfer belt 1, which suppresses a deformation of the reinforcing fibrous substrate layer 11, and thus a deformation of the wet paper transfer belt 1.

The polyester resin that constitutes the polyester yarn contained in the second warp yarns 117 is not particularly limited, though it includes, for example, polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, etc., which can be used either alone or in combination of two or more types.

Among those mentioned above, the polyester resin preferably comprises one or more types selected from a group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, more preferably one or more types selected from a group consisting of polyethylene terephthalate, polytrimethylene terephthalate and polybutylene terephthalate. By this, the swelling is suppressed during the use of the wet paper transfer belt 1, which suppresses a deformation of the reinforcing fibrous substrate layer 11, and thus a deformation of the wet paper transfer belt 1.

Moreover, the polyester yarn contained in the second warp yarns 117 may comprise a resin other than the polyester resin. Such resin is not particularly limited, and includes such as, for example, an aliphatic polyamide (polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, etc.), an aromatic polyamide (aramid), polyvinylidene fluoride, polypropylene, polyether ether ketone, polytetrafluoroethylene, and polyethylene.

In such cases, the polyester yarn contained in the second warp yarns 117 may be a yarn that comprises a mixture of a polyester resin and a resin other than the polyester resin, or may be a combined filament yarn of a fiber of a polyester resin and a fiber of a resin other than the polyester resin. However, in such cases, the content of the polyester resin included in the polyester yarn contained in the second warp yarns 117 is preferably equal to or higher than 50% by mass, more preferably equal to or higher than 65% by mass. In particular, the polyester yarn contained in the second warp yarns 117 further preferably consists essentially of a polyester resin, particularly preferably consists of a polyester resin.

Moreover, there are a plurality of second warp yarns 117 in the reinforcing fibrous substrate layer 11, which may all be polyester yarns, or which may comprise, in addition to the polyester yarn, a yarn of a resin other than the polyester resin. The yarn of a resin other than the polyester resin is not particularly limited, and is constituted with one or more types of resins such as, for example, an aliphatic polyamide (polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, etc.), an aromatic polyamide (aramid), polyvinylidene fluoride, polypropylene, polyether ether ketone, polytetrafluoroethylene, and polyethylene.

Furthermore, in this case, among the plurality of second warp yarns 117, preferably equal to or higher than 50%, more preferably equal to or higher than 65%, further preferably equal to or higher than 80% of the yarns are polyester yarns. Preferably, all second warp yarns are polyester yarns. By this, the aforementioned effect of the polyester yarn can more certainly be achieved.

The materials which constitute the first warp yarns 115 and the weft yarns 119 are not particularly limited, and a polyester (polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), an aliphatic polyamide (polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, etc.), an aromatic polyamide (aramid), polyvinylidene fluoride, polypropylene, polyether ether ketone, polytetrafluoroethylene, polyethylene, sheep wool, cotton, metals, etc. can be used either alone or in combination of two or more types.

Two or more of the first warp yarns 115, the second warp yarns 117 and the weft yarns 119 may comprise identical materials or may comprise different materials to each other.

Among those mentioned above, the first warp yarns 115 preferably comprise one or more types selected from a group consisting of a polyester, an aliphatic polyamide, an aromatic polyamide (aramid), more preferably comprise one or more types selected from a group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, and polyamide 612. This makes it possible to achieve both the maintenance of the strength and the stability of the dimensions of the wet paper transfer belt 1 when being used.

Among those mentioned above, the weft yarns 119 preferably comprise one or more types selected from a group consisting of a polyester, an aliphatic polyamide, an aromatic polyamide (aramid), more preferably comprise one or more types selected from a group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, and polyamide 612. This makes it possible to achieve both the maintenance of the strength and the stability of the dimensions of the wet paper transfer belt 1 when being used.

Moreover, the fineness of the first warp yarns 115 is not particularly limited, and it is, for example, equal to or higher than 500 dtex and equal to or lower than 8000 dtex, preferably equal to or higher than 1000 dtex and equal to or lower than 6000 dtex, more preferably equal to or higher than 2000 dtex and equal to or lower than 4000 dtex. By this, a sufficient rigidity of the reinforcing fibrous substrate 111 can be achieved, and the warping of the wet paper transfer belt 1 at its end part towards the wet paper web carrying-side and the roll-side can more effectively be suppressed.

Moreover, the fineness of the second warp yarns 117 is not particularly limited, though it is, for example, equal to or higher than 500 dtex and equal to or lower than 8000 dtex, preferably equal to or higher than 1000 dtex and equal to or lower than 6000 dtex, more preferably equal to or higher than 2000 dtex and equal to or lower than 4000 dtex. This ensures a sufficient strength of the reinforcing fibrous substrate 111 and thus a sufficient strength of the wet paper transfer belt 1, while more effectively suppressing the warping of the wet paper transfer belt 1 at its end part.

Moreover, it is preferred that the fineness of the first warp yarns 115 is greater than the fineness of the second warp yarns 117. In this way, the fineness of the first warp yarns 115 on the first plane 131-side on which the wet paper web W is placed is greater as compared to the fineness of the second warp yarns 117 on the opposite second plane 151-side, which increases the density of the woven fabric on the first plane 131-side (the wet paper web carrying-side), resulting in an increase in the rigidity on the first plane 131-side (the wet paper web carrying-side). By this, in the reinforcing fibrous substrate layer provided with the woven fabric, the warping at its end part towards the first plane 131-side (the wet paper web carrying-side) is further suppressed.

Specifically, the fineness of the first warp yarns 115 can be greater than the fineness of the second warp yarns 117 by 50 dtex or more, preferably by 100 dtex or more, more preferably by 200 dtex or more. By this, the warping of the wet paper transfer belt 1 at the end part during its use can more efficiently be suppressed. Moreover, the fineness of the first warp yarns 115 can be greater than the fineness of the second warp yarns 117 in a range, for example, by 3000 dtex or less, preferably by 2500 dtex or less, more preferably by 1000 dtex or less. By this, it can be suppressed that the fineness of the first warp yarns 115 becomes high to an undue degree as compared to the fineness of the second warp yarns 117 so that the end part of the wet paper transfer belt 1 would warp towards the roll-side.

The fineness of the weft yarns 119 is not particularly limited, and for example, it is equal to or higher than 500 dtex and equal to or lower than 6000 dtex, preferably equal to or higher than 800 dtex and equal to or lower than 3000 dtex, more preferably equal to or higher than 1000 dtex and equal to or lower than 2000 dtex. This ensures a sufficient strength of the reinforcing fibrous substrate 111 and thus a sufficient strength of the wet paper transfer belt 1, while sufficiently suppressing the waving associated with the weaving of the reinforcing fibrous substrate 111.

The first warp yarns 115, the second warp yarns 117 and the weft yarns 119 may be yarns of any form, may be spun yarns (spun threads) or filament yarns. However, in view of ensuring the strength of the reinforcing fibrous substrate 111, thus of the wet paper transfer belt 1, the first warp yarns 115, the second warp yarns 117 and the weft yarns 119 are all preferably filament yarns. The first warp yarns 115, the second warp yarns 117 and the weft yarns 119 may be yarns of different forms to each other, or they may be yarns of an identical form.

A filament yarn includes, for example, a multifilament or monofilament twist yarn, a multifilament or monofilament paralleled yarn and a monofilament single yarn, etc.

Herein, a “multifilament” is a filament that comprises two or more single yarns. Normally, a single yarn that constitutes a multifilament has the fineness that is not enough to be used alone as a yarn for a reinforcing fibrous substrate. Specifically, the fineness of a single yarn that constitutes a multifilament is, for example, less than 100 dtex, preferably equal to or higher than 5 dtex and equal to or less than 50 dtex. On the other hand, a monofilament is a filament consisting of one yarn. Normally, a single yarn that constitutes a monofilament has the fineness that is enough to be used alone as a yarn for a reinforcing fibrous substrate. The fineness of a monofilament is, for example, equal to or higher than 100 dtex and equal to or less than 6000 dtex, preferably equal to or higher than 200 dtex and equal to or less than 2500 dtex.

A “multifilament twist yarn” refers to a twist yarn in which a multifilament is used as an original yarn. A “paralleled multifilament yarn” refers to a yarn in which a plurality of the above-described single yarns that constitutes a multifilament are arranged in parallel as original yarns.

When a multifilament or monofilament paralleled yarn is used, the paralleled yarn can be obtained by parallelly placing the original yarns such that the resulting filament yarn has the intended fineness, for example. In this case, the fineness of the single yarn that constitutes the multifilament original yarn is preferably equal to or higher than 5 dtex and less than 100 dtex, more preferably equal to or higher than 5 dtex and equal to or less than 50 dtex. The fineness of the original yarn of a monofilament is preferably equal to or higher than 100 dtex and equal to or less than 1000 dtex, more preferably equal to or higher than 100 dtex and equal to or less than 500 dtex.

When a multifilament or monofilament twist yarn is used, a plied or single twist yarn may be used. In a case of a plied yarn, for example, a plurality of original yarns are arranged in parallel such that the fineness will be equal to or higher than 200 dtex and equal to or less than 2500 dtex, preferably equal to or higher than 300 dtex and equal to or less than 2000 dtex, and these parallelly placed original yarns are twisted. Then, several, for example, from 2 to 10 of the twisted, paralleled original yarns are arranged in parallel to achieve the intended fineness, are further twisted to yield a multifilament or monofilament plied yarn. In this case, the number of primary twists is not particularly limited, and it is, for example, equal to or more than 0.05 twists/cm and equal to or less than 20.0 twists/cm, preferably equal to or more than 0.1 twists/cm and equal to or less than 10.0 twists/cm. The number of final twists is not particularly limited, for example, equal to or more than 0.05 twists/cm and equal to or less than 20.0 twists/cm, preferably equal to or more than 0.1 twists/cm and equal to or less than 10.0 twists/cm.

In a case of single twist, a plurality of original yarns are arranged in parallel to achieve an intended fineness, and these parallelly arranged original yarns are twisted together to yield a multifilament or monofilament single twist yarn. This can give a twist yarn. In this case, the number of twists is not particularly limited, and it is, for example, equal to or more than 0.05 twists/cm and equal to or less than 20.0 twists/cm, preferably equal to or more than 0.1 twists/cm and equal to or less than 10.0 twists/cm.

When a twist yarn is used, the fineness of the single yarn that constitutes the multifilament original yarn is preferably equal to or higher than 5 dtex and less than 100 dtex, more preferably equal to or higher than 5 dtex and equal to or less than 50 dtex. The fineness of the monofilament original yarn is preferably equal to or higher than 200 dtex and equal to or less than 1500 dtex, more preferably equal to or higher than 300 dtex and equal to or less than 1000 dtex.

Moreover, the first warp yarns 115, the second warp yarns 117 and the weft yarns 119 may appropriately be processed. Such processing includes stretching process, crimping process, etc.

The first warp yarns 115 comprise, among those mentioned above, preferably monofilaments, more preferably monofilament twist yarns, and further preferably comprises monofilament plied yarns.

The second warp yarns 117 comprises, among those mentioned above, preferably multifilaments, more preferably multifilament twist yarns, further preferably comprises multifilament single twist yarns. By using multifilament single twist yarns as the second warp yarns 117, the rate at which the resin material impregnates from the second plane 151-side can be decreased during the production of the wet paper transfer belt 1, and a second resin layer 15 having a sufficient thickness can be formed without forming a batt fiber layer. As a result thereof, it becomes possible to omit the batt fiber layer, and the warping of the wet paper transfer belt 1 at its end part is further suppressed.

Furthermore, it is preferred that the second warp yarns 117 have been crimped. This makes it possible to decrease the rate at which the resin material impregnates from the second plane 151-side during the production of the wet paper transfer belt 1, and the second resin layer 15 having a sufficient thickness can be formed.

The weft yarns 119 comprise, among those mentioned above, preferably monofilaments, more preferably monofilament twist yarns, and further preferably comprise monofilament plied yarns. By this, the warping of the wet paper transfer belt 1 at the end part during its use can more efficiently be suppressed.

Moreover, as mentioned above, the reinforcing fibrous substrate 111 is a woven fabric having a double weave pattern comprising the first warp yarns 115 and the second warp yarns 117 as warp yarns, and the weft yarns 119 as a weft yarns. Hereinbelow, the weave pattern of the reinforcing fibrous substrate 111 is described with reference to FIGS. 2 to 4.

As shown in FIG. 2, and also as mentioned above, in the double weave pattern of the reinforcing fibrous substrate 111, the first warp yarns 115 are placed on the first plane 131-side (the wet paper web carrying-side), whereas the second warp yarns 117 are placed on the opposite side to the first plane side, i.e., the second plane 151-side (the roll-side). Moreover, the weft yarns 119 are woven into the first warp yarns 115 and the second warp yarns 117 to form a fabric weave pattern of the reinforcing fibrous substrate 111.

Specifically, in context with the relationship between the first warp yarns 115 and the weft yarns 119, they have repeats in which each weft yarn 119 passes through the first plane 131-side of one first warp yarn 115 (in FIG. 2; 1, 5, 9, 13, 17), and subsequently passes through the second plane 151-side of three first warp yarns 115 (in FIG. 2; 2-4, 6-8, 10-12, 14-16, 18-20). Also, in context with the relationship between the second warp yarns 117 and the weft yarns 119, they have repeats in which each weft yarn 119 passes through the first plane 131-side of seven second warp yarns 117 (in FIG. 2; 4-10, 12-18), and subsequently passes through the second plane 151-side of one second warp yarn 117 (in FIG. 2; 3, 11, 19). Furthermore, the combination weave pattern of the reinforcing fibrous substrate 111 has a repeat unit R, so that it is possible to form this repeating relationship between the first warp yarns 115 and the weft yarns 119 and that between the second warp yarns 117 and the weft yarns 119 at the same time.

In the description below, a fabric weave pattern that has a repeat unit that is capable of forming at the same time a repeat in which each weft yarn passes through the first plane-side of K first warp yarns, and subsequently passes through the second plane-side of L first warp yarns, and a repeat in which each weft yarn passes through the first plane-side of M second warp yarns, and subsequently passes through the second plane-side of N second warp yarns is also described “L/K N/M”. Therefore, the fabric weave pattern shown in FIG. 2 can be written as a “3/1 1/7” double weave pattern.

Furthermore, it is preferred that the aforementioned K, L, M and N satisfy the relation K/L N/M. This increases the density of the reinforcing fibrous substrate 111 on the wet paper web carrying (the first plane 131)-side of the woven fabric, resulting in an increase in its rigidity on the wet paper web carrying-side. Therefore, the warping of the reinforcing fibrous substrate 111 at the end part towards the wet paper web carrying-side is suppressed, the warping of the wet paper transfer belt 1 at the end part during its use, the wet paper web carrying-side is more effectively suppressed. Further preferably K, L, M and N satisfy the relationship K/L>N/M.

FIG. 3 is a diagram of a weave repeat showing the relationship between the first warp yarns 115 and the weft yarns 119 of the reinforcing fibrous substrate 111. From this diagram of the weave repeat, it is possible to tell which of the first warp yarn 115 and the weft yarn 119 is exposed on the first plane 131-side when the reinforcing fibrous substrate 111 is observed in a planar view from the first plane 131-side. In FIG. 3, in a black part, the first warp yarn 115 is exposed on the first plane 131-side, whereas, in a white part, the weft yarn 119 is exposed on the first plane 131-side. In other words, in the white part, the weft yarn 119 intersects with the first warp yarn 115 and turns back, forming a crossing point (knuckle part). In the present embodiment, the number of crossing points between the weft yarns 119 and the first warp yarns 115 in the weave repeat is 16.

FIG. 4 is a diagram of a weave repeat showing the relationship between the second warp yarns 117 and the weft yarns 119 of the reinforcing fibrous substrate 111. From this diagram of the weave repeat, it is possible to tell which of the second warp yarn 117 and the weft yarn 119 is exposed on the second plane 151-side when the reinforcing fibrous substrate 111 is observed in a planar view from the second plane 151-side. In FIG. 4, in a black part, the second warp yarn 117 is exposed on the second plane 151-side, whereas, in a white part, the weft yarn 119 is exposed on the second plane 151-side. In other words, in the white part, the weft yarn 119 intersects with the second warp yarn 117 and turns back, forming a crossing point (knuckle part). In the present embodiment, the number of crossing points between the weft yarns 119 and the second warp yarns 117 in the weave repeat is 8.

Thus, in the present embodiment, the number of crossing points between the weft yarns 119 and the first warp yarns 115 in the weave repeat is greater than the number of crossing points between the weft yarns 119 and the second warp yarns 117 in the weave repeat. This increases the density of the reinforcing fibrous substrate 111 on the wet paper web carrying (the first plane 131)-side of the woven fabric, resulting in an increase in its rigidity on the wet paper web carrying-side. Therefore, the warping of the reinforcing fibrous substrate 111 at the end part towards the wet paper web carrying-side is suppressed, the warping of the wet paper web transfer belt 1 at the end part during its use, and the warping towards the wet paper web carrying-side is more effectively suppressed.

Moreover, the reinforcing fibrous substrate 111 may comprise, in addition to the specific woven fabrics as mentioned above, other woven fabrics and/or other fiber materials such as an unwoven grid-like material in which columns of warp yarns and rows of weft yarns are overlaid to each other. Furthermore, the reinforcing fibrous substrate 111 may comprise a yarn placed spirally along the circumferential direction.

Moreover, the fineness of a fiber that constitutes the reinforcing fibrous substrate 111 may be different depending on the part in which the fiber is used.

Materials for the resin 113 contained in the reinforcing fibrous substrate layer 11 are not particularly limited, and a thermosetting resin such as an urethane resin, an epoxy resin and an acrylic resin, or a thermoplastic resin such as a polyamide resin, a polyarylate resin and a polyester resin can be used alone or in combination of two or more types. Preferably, an urethane resin can be used. The urethane resin used in the resin 113 is not particularly limited, though it can be, for example, urethane resin obtained by curing a urethane prepolymer having a terminal isocyanate group obtained by reacting a polyisocyanate compound and a polyol with a curing agent having an active hydrogen group. An anionic, nonionic or cationic, self-emulsifying or forcibly-emulsifying aqueous urethane resin can also be used.

As mentioned above, urethane resin comprises, for example, an aqueous urethane resin, and/or urethane resin obtained by curing a urethane prepolymer having a terminal isocyanate group obtained by reacting a polyisocyanate compound and a polyol with a curing agent having an active hydrogen group. Note that any urethane resin is formed using a polyisocyanate compound, a polyol and a curing agent as necessary. Therefore, hereinbelow, polyisocyanate compounds, polyols and curing agents that constitutes the urethane resin will be described.

The polyisocyanate compound includes an aromatic polyisocyanate compound and an aliphatic polyisocyanate compound, which can be used either alone or in combination of two or more types. The aromatic polyisocyanate compound includes, for example, 2,4-tolylene-diisocyanate (2,4-TDI), 2,6-tolylene-diisocyanate (2,6-TDI), 4,4′-methylenebis(phenylisocyanate) (MDI), p-phenylene-diisocyanate (PPDI), dimethylbiphenylene diisocyanate (TODD, naphthalene-1,5-diisocyanate (NDI), 4,4-dibenzyldiisocyanate (DBDI), xylylene diisocyanate (XDI), tetramethylxylylene-diisocyanate (TMXDI), polymethylene polyphenyl polyisocyanate (polymeric MDI), etc.

The aliphatic polyisocyanate compound is not particularly limited, though includes, for example, a chainlike aliphatic polyisocyanate such as 1,6-hexamethylene diisocyanate (HDI) and 1,5-pentamethylene diisocyanate, and an alicyclic polyisocyanate such as 1-isocyanate-3-isocyanatemethyl-3,5,5-trimethylcyclohexane (IPDI), dicyclohexylmethane-4,4′-diisocyanate (H12MD1), 1,3-cyclohexyldiisocyanate, 1,4-cyclohexyldiisocyanate (CHDI) and 1,4-bis-(isocyanatemethyl)cyclohexane (H6XD1), which can be used either alone or in combination of two or more types.

Among those mentioned above, the polyisocyanate compound preferably comprises one or more types selected from a group consisting of an aromatic polyisocyanate compound and an aliphatic polyisocyanate compound, more preferably one or more types selected from a group consisting of 2,4-tolylene-diisocyanate (2,4-TDI), 2,6-tolylene-diisocyanate (2,6-TDI), 4,4′-methylenebis(phenylisocyanate) (MDI), 1-isocyanate-3-isocyanatemethyl-3,5,5-trimethylcyclohexane (IPDI), and dicyclohexylmethane-4,4′-diisocyanate (H12MD1). By this, each of the crack resistance, abrasion resistance, wet paper web-transferring ability (balance between the adhesion and detachability of the wet paper web W with the wet paper transfer belt 1) of the wet paper transfer belt 1 can be improved.

The polyol compound is not particularly limited, and includes a long-chain polyol compound, for example, a polyester polyol such as polycaprolactone polyol and polyethylene adipate, a polyether polyol such as polyethylene glycol, polyoxypropylene glycol, polyhexamethylene ether glycol and polytetramethylene ether glycol (PTMG), a polycarbonate polyol such as polycarbonate diol, polyether carbonate diol, polybutadiene polyol, perfluoropolyether polyol, a silicon polyol such as silicon diol, which can be used either alone or in combination of two or more types.

The polycarbonate polyol is not particularly limited, though it includes, for example, a polycarbonate polyol synthesized from a polyol as a raw material of the polycarbonate polyol and a polycarbonate source. The polyol as a raw material of the polycarbonate polyol is not particularly limited, though it includes, such as, for example, a straight chain or branched chain alkylene glycol having 2 or more and 20 or less of carbon atoms, a hydrogen-containing cyclic hydrocarbon having 2 or more and 20 or less of carbon atoms, which can be used either alone or in combination of two or more types. The above-described straight chain alkylene glycol includes, for example, ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, undecanediol, dodecanediol, etc. The above-described branched chain alkylene glycol includes, for example, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, etc. The above-described hydrogen-containing cyclic hydrocarbon includes, for example, a hydroxyl group-containing alicyclic alkane such as 1,3-cyclohexane diol, 1,4-cyclohexane diol and 1,4-cyclohexane dimethanol.

Among those mentioned above, polyol compound preferably comprises one or more types selected from a group consisting of polyether polyol, polycarbonate polyol and polyether carbonate diol, more preferably one or more types selected from a group consisting of polytetramethylene ether glycol (PTMG) and polycarbonate polyol synthesized from hexanediol and a polycarbonate source. By this, each of the crack resistance, abrasion resistance, wet paper web-transferring ability (balance between the adhesion and detachability of the wet paper web W with the wet paper transfer belt 1) of the wet paper transfer belt 1 can be improved.

The curing agent having an active hydrogen group is not particularly limited, and one or more type(s) of compound(s) selected from a group consisting of polyol compounds and polyamines can be used.

As the polyol compound that can be contained in the curing agent, in addition to the aforementioned long-chain polyol compounds, various aliphatic polyol compounds and various alicyclic or aromatic polyol compounds can be used.

The aliphatic polyol compound is not particularly limited, and include, for example, a alkylene glycol compound such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-icosanediol, 2-methyl-1,3-propanediol, neopentylglycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, and a glycerin, ditrimethylolpropane, trimethylolpropane (TMP), pentaerythritol, and dihydroxymethyl propionic acid (DHPA), etc.

The alicyclic polyol compound is not particularly limited, and includes, for example, 1,4-cyclohexane dimethanol, hydrogenated bisphenol A, etc.

The aromatic polyol compound is not particularly limited, and includes for example, hydroquinone bis-β-hydroxyethylether (HQEE), hydroxyphenylether resorcinol (HER), 1,3-bis(2-hydroxyethoxybenzene), 1,4-bis(2-hydroxyethoxybenzene), bisphenol A, an alkylene oxide adduct of bisphenol A, bisphenol S, an alkylene oxide adduct of bisphenol S, etc.

The polyamine is not particularly limited, and include hydrazine, ethylenediamine, 4,4′-methylene-bis-(2-chloroaniline) (MOCA), dimethylthiotoluene diamine (DMTDA), diethyltoluene diamine (DETDA), trimethylene glycol di(p-aminobenzoate) (TMAB), 4,4′-methylene-bis-(3-chloro-2,6-diethylaniline) (MCDEA), 4,4′-methylene-bis-(2,6-diethylaniline) (MDEA), triisopropanolamine (TIPA), p-bis(aminocyclohexyl)methane (PACM), naphthalene-1,5-diamine, xylylene diamine, phenylenediamine, toluene-2,4-diamine, t-butyltoluene diamine, 1,2-bis(2-aminophenylthioethane), 2-(2-aminoethylamino)ethanol, etc.

Among those mentioned above, the curing agent preferably comprises one or more types selected from a group consisting of a aliphatic polyol compound and a polyamine, more preferably one or more types selected from a group consisting of ethylene glycol, butanediol, trimethylolpropane (TMP), dimethylthiotoluene diamine (DMTDA) and diethyltoluene diamine (DETDA). By this, each of the crack resistance, abrasion resistance, wet paper web-transferring ability (balance between the adhesion and detachability of the wet paper web W with the wet paper transfer belt 1) of the wet paper transfer belt 1 can be improved.

The resin 113 of the reinforcing fibrous substrate layer 11 may be crosslinked with a crosslinking agent. The crosslinking agent includes various crosslinking agents such as that of a carbodiimide-type, a melamine-type, an epoxy-type and an isocyanate-type, which can be used either alone or in combination of two or more types. Furthermore, the crosslinking agent may be a crosslinking agent composition comprising a solvent, a dispersing agent, a surfactant, etc., or may be a liquid (for example, a solution, a dispersion, or an emulsion). When the crosslinking agent is in a form of a solution, the crosslinking agent may be an aqueous solution.

The above-described crosslinking agent may be used being admixed with materials for constituting a urethane resin, for example, a urethane prepolymer and a curing agent, or may be used being admixed with a dispersion of an aqueous urethane resin.

Moreover, the resin 133 may comprise an inorganic filler such as titanium oxide, kaoline, clay, talc, diatomaceous earth, calcium carbonate, calcium silicate, magnesium silicate, silica and mica, either alone or in combination of two or more types.

Moreover, the composition and type of the resin 113 in the reinforcing fibrous substrate layer 11 may be different or identical depending on the part in the reinforcing fibrous substrate layer 11.

The first resin layer 13 is a layer which principally be constituted with a resin provided on one principal plane of the reinforcing fibrous substrate layer 11.

The first resin layer 13 constitutes a first plane 131 on which a wet paper web W is placed on a principal plane that is opposite to the principal plane joined to the reinforcing fibrous substrate layer 11. That is, the wet paper transfer belt 1 can carry the wet paper web Won the first plane 131 of the first resin layer 13 and transfer the wet paper web W. In an embodiment shown in the drawings, the wet paper web W is placed directly on the first plane 131. However, the wet paper web W may also be placed indirectly on the first plane 131. For example, depending on the embodiment used, a different device, for example, a felt, etc., may be placed between the first plane 131 and the wet paper web W, and the wet paper web W may be placed via the different device on the first plane 131.

A material for a resin that constitutes the first resin layer 13 is not particularly limited, and, for example, aforementioned various resins that can be used as the resin 113 of the reinforcing fibrous substrate layer 11 can be used either alone or in combination of two or more types. The resin that constitutes the first resin layer 13 may be identical to or different from the resin 113 of the reinforcing fibrous substrate layer 11 for their types or compositions.

Moreover, a resin that constitutes the first resin layer 13 may comprise an inorganic filler such as titanium oxide, kaoline, clay, talc, diatomaceous earth, calcium carbonate, calcium silicate, magnesium silicate, silica and mica, either alone or in combination of two or more types. By including such an inorganic filler in the resin that constitutes the first resin layer 13, the surface state of the first plane 131 such as a state of irregularity, surface roughness, and hydrophilicity of the first plane 131 of the first resin layer 13 can be more easily controlled, and functions, which are required for the wet paper transfer belt 1, of transferring a wet paper web W adhered thereto (wet paper web adhesion) and smoothly detaching the wet paper web W while delivering the wet paper web W to a following step (wet paper web detachability) can more certainly be achieved.

On the other hand, the inorganic filler is, when using the wet paper transfer belt 1, less easy to absorb moisture compared to other parts that constitute the wet paper transfer belt 1, and therefore it tends to become one of the causes for developing the warping of the wet paper transfer belt 1 at its end part. However, in the present embodiment, by providing the wet paper transfer belt 1 with the aforementioned reinforcing fibrous substrate 111, the warping of the wet paper transfer belt 1 at its end part is sufficiently suppressed even when using the inorganic filler.

Moreover, the first resin layer 13 preferably has a characteristic that water does not permeate it. That is, the first resin layer 13 preferably is water-impermeable.

A second resin layer (a roll-side resin layer) 15 is a layer which principally be constituted with a resin provided on one principal plane of the reinforcing fibrous substrate layer 11.

The second resin layer 15, on a principal plane that is opposite to the principal plane joined to the reinforcing fibrous substrate layer 11, constitutes a second plane 151 that is to be in contact with a roll mentioned later. The wet paper transfer belt 1 can obtain a motive power from a roll for transferring a wet paper web via the contact of the second plane 151 with the roll when being used. Furthermore, in the second plane 151, an irregularity can be formed by placing the second warp yarns 117 on the second plane 151, which can prevent slipping of the roll on the wet paper transfer belt 1, so-called hydroplaning phenomenon.

As a resin that constitutes the second resin layer 15, the resin materials that can be used in the first resin layer 13 as mentioned above can be used either alone or in combination of two or more. The resin that constitutes the second resin layer 15 may be identical to or different from the resin that constitutes the first resin layer 13 or the resin 113 that constitutes the reinforcing fibrous substrate layer 11 for their types and compositions.

Moreover, the second resin layer 15 may comprise one or more inorganic filler(s) in a similar way to the first resin layer 13.

Note that the composition and type of the resin material and the inorganic filler in the second resin layer 15 may be different or identical between the parts in the second resin layer 15.

The dimensions of the wet paper transfer belt 1 is not particularly limited, and can appropriately be set according to its application.

For example, the width of the wet paper transfer belt 1 is not particularly limited, though it can be from 700 mm to 13500 mm, preferably, from 2500 mm to 12500 mm.

Moreover, for example, the length (circumference) of the wet paper transfer belt 1 is not particularly limited, though it can be from 4 m to 35 m, preferably from 10 m to 30 m.

The thickness of the wet paper transfer belt 1 is not particularly limited, though for example, can be from 1.5 mm to 7.0 mm, preferably from 2.0 mm to 6.0 mm.

The thickness of the wet paper transfer belt 1 may be different or identical between parts.

The wet paper transfer belt 1 as described above can be produced by, for example, a method of producing a wet paper transfer belt according to the present embodiment mentioned later.

As above, the wet paper transfer belt 1 according to the present embodiment comprises a reinforcing fibrous substrate 111 comprising a woven fabric having a double weave pattern, and second warp yarns 117 in woven fabric comprises a polyester yarn. By this, the warping the end part of the wet paper transfer belt 1 during its use, i.e., at the end part in the width direction (CMD) is suppressed. As a result, the automatic guiding apparatus can detect the position of the wet paper transfer belt 1 with a higher accuracy, and can more appropriately control the position of the wet paper transfer belt 1. Such a wet paper transfer belt 1 is capable of being stably used.

3. MODIFIED EXAMPLES

Next, some modified examples of the papermaking belts according to the aforementioned embodiments are to be explained. Hereinbelow, differences from the aforementioned embodiments are mainly explained, and the description about similar matters is omitted. Characteristics of the modified examples described below and embodiments mentioned above may each be applied alone, though two or more may be applied in combination as long as it is technically acceptable.

3.1 First Modified Example

FIG. 5 is an enlarged cross-sectional view of a reinforcing fibrous substrate provided in a wet paper transfer belt (papermaking belt) according to a first modified example, and FIG. 6 and FIG. 7 is a diagram of a weave repeat of a woven fabric of the reinforcing fibrous substrate provided in the wet paper transfer belt of FIG. 5.

The wet paper transfer belt 1A according to the first modified example is different from the aforementioned embodiments only in that it comprises a reinforcing fibrous substrate 111A as described in FIGS. 5 to 7 in place of the reinforcing fibrous substrate 111 in the aforementioned embodiments, but others are basically similar. Hereinbelow, the reinforcing fibrous substrate 111A is to be explained.

The reinforcing fibrous substrate 111A is a woven fabric having double weave pattern, comprising first warp yarns 115A, second warp yarns 117A, and weft yarns 119A. In a double weave pattern of the reinforcing fibrous substrate 111A, the first warp yarns 115A are placed on a first plane-side (the wet paper web carrying-side, not illustrated), and the second warp yarns 117A are placed on the opposite side to the first plane side, i.e., a second plane-side (the roll-side, not illustrated). Moreover, the first warp yarns 115A and the second warp yarns 117A are placed in parallel. Furthermore, the first warp yarns 115A and the second warp yarns 117A are placed along the machine direction (MD). On the other hand, the weft yarns 119A are placed approximately perpendicular to the first warp yarns 115A and the second warp yarns 117A, i.e., along the cross machine direction (CMD). The weft yarns 119A are woven into the first warp yarns 115A and the second warp yarns 117A.

Specifically, in context with the relationship between the first warp yarns 115A and the weft yarns 119A, they have repeats in which each weft yarn 119A passes through the first plane-side of one first warp yarn 115A (in FIG. 5; 1, 5, 9, 13, 17), and subsequently passes through the second plane-side of three first warp yarns 115A (in FIG. 5; 2-4, 6-8, 10-12, 14-16). Also, in context with the relationship between the second warp yarns 117A and the weft yarns 119A, they have repeats in which each weft yarn 119A passes through the first plane-side of three second warp yarns 117A (in FIG. 5; 4-6, 8-10, 12-14, 16-18), and subsequently passes through the second plane-side of one first warp yarn 115A (in FIG. 5; 3, 7, 11, 15). Furthermore, the combination weave pattern of the reinforcing fibrous substrate 111A has a repeat unit R′, so that it is possible to form this repeating relationship between the first warp yarns 115A and the weft yarns 119A and that between the second warp yarns 117A and the weft yarns 119A at the same time. As described above, the fabric weave pattern of the reinforcing fibrous substrate 111 shown in FIG. 5 can be written as a “3/1 1/3” double weave pattern.

FIG. 6 is a diagram of a weave repeat showing the relationship between the first warp yarns 115A and the weft yarns 119A of the reinforcing fibrous substrate 111A. From this diagram of the weave repeat, it is possible to tell which of the first warp yarn 115A and the weft yarn 119A is exposed on the first plane-side when the reinforcing fibrous substrate 111A is observed in a planar view from the first plane-side. In FIG. 6, in a black part, the first warp yarn 115A is exposed on the first plane-side, whereas, in a white part, the weft yarn 119A is exposed on the first plane-side. In other words, in the white part, the weft yarn 119A intersects with the first warp yarn 115A and turns back, forming a crossing point (knuckle part). In this modified example, the number of crossing points between the weft yarns 119A and the first warp yarns 115A in the weave repeat is 4.

FIG. 7 is a diagram of a weave repeat showing the relationship between the second warp yarns 117A and the weft yarns 119A of the reinforcing fibrous substrate 111A. From this diagram of the weave repeat, it is possible to tell which of the second warp yarn 117A and the weft yarn 119A is exposed on the second plane-side when the reinforcing fibrous substrate 111A is observed in a planar view from the second plane-side. In FIG. 7, in a black part, the second warp yarn 117A is exposed on the second plane-side, whereas, in a white part, the weft yarn 119A is exposed on the second plane-side. In other words, in the white part, the weft yarn 119A intersects the second warp yarn and turns back, forming a crossing point (knuckle part). In this modified example, the number of crossing points between the weft yarns 119A and the second warp yarns 117A in the weave repeat is 4.

In the wet paper transfer belt 1A as above, too, the second warp yarns 117A comprises a polyester yarn. By this, an effect that is similar to those of the aforementioned embodiments is exhibited.

3.2 Second Modified Example

FIG. 8 is a cross-sectional view in a cross machine direction of a wet paper transfer belt (papermaking belt) according to a second modified example. A wet paper transfer belt 1B according to the second modified example is different from the aforementioned embodiments in that it comprises a first resin layer 13B in which batt fibers are impregnated with a resin material and a second resin layer 15B in which batt fibers are impregnated with a resin material in place of the first resin layer 13 and the second resin layer 15 in the aforementioned embodiments.

The first resin layer 13B is obtained by impregnating a batt fiber layer formed on the reinforcing fibrous substrate layer 11B with a resin material. Therefore, the first resin layer 13B comprises the batt fibers and the resin as a matrix. As the resin material for the first resin layer 13B, materials that are similar to the resin materials for the first resin layer 13 in the aforementioned embodiments can be used. Moreover, as materials for the batt fibers, the materials that can be used for the reinforcing fibrous substrate 111 in the aforementioned embodiments can be used either alone or in combination of two or more types.

The second resin layer 15B is obtained by impregnating a batt fiber layer formed on the reinforcing fibrous substrate layer 11B with a resin material. Therefore, the second resin layer 15B comprises the batt fibers, and the resin as a matrix. As the resin material for the second resin layer 15B, materials that are similar to the resin materials for the first resin layer 13 in the aforementioned embodiments can be used. Moreover, as materials for the batt fibers, the materials that can be used for the reinforcing fibrous substrate 111 in the aforementioned embodiments can be used either alone or in combination of two or more types.

Furthermore, on both sides of the reinforcing fibrous substrate layer 11B, batt fiber layers are placed together with the formation of the first resin layer 13B and second resin layer 15B as mentioned above. Such batt fiber layers is formed by placing batt fibers on both sides of the reinforcing fibrous substrate layer 11B, and needling the batt fibers so that the batt fibers get entangled in the reinforcing fibrous substrate layer 11B. Therefore, the batt fibers are entangled in the reinforcing fibrous substrate 111B of the reinforcing fibrous substrate layer 11B. Moreover, other constituents of the reinforcing fibrous substrate layer 11B are similar to those of the reinforcing fibrous substrate 111 of the aforementioned embodiments.

As described above, in this modified example, the first resin layer 13B and the second resin layer 15B comprise not only resins but also batt fibers. When the first resin layer 13B and the second resin layer 15B thus comprise batt fibers, the first plane 131B of the first resin layer 13B and the second plane 151B of the second resin layer 15B will have an appropriate irregularity. This makes it easier to control adhesion to and detaching from the wet paper web W in the first plane 131B. Moreover, in the second plane 151B, sufficient friction can be obtained against the roll in contact, and the motive power from the roll can more efficiently be transferred to the wet paper transfer belt 1. Furthermore, in the second plane 151B, an irregularity can be formed by placing the batt fibers on the second plane 151B, which can prevent slipping of the roll on the wet paper transfer belt 1B, so-called hydroplaning phenomenon.

Furthermore, when a resin material is applied during the formation of the first resin layer 13B and the second resin layer 15B, the speed at which the resin material is impregnated in the batt fibers and the reinforcing fibrous substrate layer 11B is smaller as compared to the case when there is no batt fibers. This can result in a sufficient thickness of the first resin layer 13B and the second resin layer 15B, providing a sufficient durability and strength of the wet paper transfer belt 1.

On the other hand, as is the case of the first resin layer 13B and the second resin layer 15B, when batt fibers are included within a resin layer, because the batt fibers absorb moisture and swell, the end part of the wet paper transfer belt generally tends to develop warping. However, by providing the wet paper transfer belt 1B with the reinforcing fibrous substrate layer 11B as mentioned above, the development of the warping of the wet paper transfer belt 1B at the end part is suppressed.

3.3 Other Modified Examples

In the aforementioned embodiments, the woven fabric included in the reinforcing fibrous substrate layer 11 had double weave pattern, though the present invention is not limited thereto, it may have a triple or higher combination weave pattern. In this case, one of two parallelly running warp yarns or weft yarns of the combination weave pattern of the woven fabric that is placed on the second plane-side comprises a polyester yarn. Preferably, among the parallelly running warp yarns or weft yarns of the combination weave pattern of the woven fabric, the yarns that are the closest to the second plane (roll-side) comprises a polyester yarn.

Moreover, in the aforementioned embodiments, the second warp yarns 117 of the woven fabric included in the reinforcing fibrous substrate layer 11 comprises a polyester yarn, though the present invention is not limited thereto. When the reinforcing fibrous substrate layer comprises a woven fabric that is a weft multiple weave pattern, there are two parallelly running weft yarns, of which the weft yarns on the second plane-side (roll-side) may comprise a polyester yarn.

Furthermore, in the aforementioned second modified example, the first resin layer 13B and the second resin layer 15B comprising batt fibers on both sides of the reinforcing fibrous substrate layer 11B was formed, though the present invention is not limited thereto, and a resin layer comprising batt fibers only on one plane of the reinforcing fibrous substrate layer may be formed.

4. METHODS OF PRODUCING PAPERMAKING BELTS

Next, some examples of preferred embodiments of methods of producing the aforementioned papermaking belts of the present disclosure are to be explained. In the present embodiments, as an example of a papermaking belt, a method of producing the wet paper transfer belt 1 is to be explained as a representative. The wet paper transfer belt 1 may be produced by any method. Hereinbelow, as a method of producing the wet paper transfer belt 1, Rear Surface Coating Turn-over Method and Front Surface Coating Penetration Method are explained as representatives.

First, with reference to FIGS. 9 and 10, Rear Surface Coating Turn-over Method is to be explained. FIGS. 9 and 10 are schematic diagrams for illustrating a preferred embodiment of a method of producing a papermaking belt according to the present disclosure. First, as shown in FIG. 9, an endless reinforcing fibrous substrate 111 is hung over two parallelly placed rolls 21 such that the substrate is in contact with the rolls. At this time, the reinforcing fibrous substrate 111 is placed such that first warp yarns 115 of the reinforcing fibrous substrate 111 is in contact with the rolls 21. Next, while rotating the rolls 21, from the side of the reinforcing fibrous substrate 111 on which second warp yarns 117 are placed, i.e., from the outside of the reinforcing fibrous substrate 111 that are currently being hung over, a resin material for forming a second resin layer 15 is discharged onto the surface of the reinforcing fibrous substrate 111 from a resin discharge opening 25 of a coater, and the resin material is applied using a coater bar 23. Next, the applied resin material is cured by heating to form the second resin layer 15.

Next, as shown in FIG. 10, the reinforcing fibrous substrate 111 is turned and hung over such that the formed second resin layer 15 is in contact with the rolls 21. Subsequently, a resin material that forms a resin 113 of a reinforcing fibrous substrate layer 11 and a resin that constitutes the first resin layer 13 is discharged from the resin discharge opening 25 of the coater onto the surface of the reinforcing fibrous substrate 111 and the resin material is applied using the coater bar 23. By this, the reinforcing fibrous substrate 111 is impregnated with the resin material to constitute the resin 113, and at the same time, a precursor of the first resin layer 13 is formed on the reinforcing fibrous substrate 111. Then, the resulting laminated body of the resin comprising the reinforcing fibrous substrate 111 is cured by heating to yield the wet paper transfer belt 1 in which the first resin layer 13, the reinforcing fibrous substrate layer 11 and the second resin layer 15 have been laminated in this order. Furthermore, the first plane 131 of the first resin layer 13 and/or the second plane 151 of the second resin layer 15 may be polished, using a polishing apparatus as necessary.

Next, with reference to FIGS. 11 and 12, Front Surface Coating Penetration Method is to be explained. FIGS. 11 and 12 are schematic diagrams for illustrating a preferred embodiment of a method of producing a papermaking belt according to the present disclosure. First, as shown in FIG. 11, an endless reinforcing fibrous substrate 111 is hung over two parallelly placed rolls 21 such that the substrate is in contact with the rolls. At this time, the reinforcing fibrous substrate 111 is placed such that the second warp yarns 117 of the reinforcing fibrous substrate 111 is in contact with the rolls 21. Next, while rotating the rolls, from the side of the reinforcing fibrous substrate 111 on which the first warp yarns 115 are placed, i.e., from the outside of the reinforcing fibrous substrate 111 that are currently being hung over, a resin material is discharged onto the surface of the reinforcing fibrous substrate 111 from resin discharge opening 25 of a coater, and the resin material is applied using a coater bar 23. The resin material applied at this time can penetrate into the reinforcing fibrous substrate 111. Therefore, in the present embodiment, it is possible to form not only the resin 113 contained in the reinforcing fibrous substrate 111, but also the resin that constitutes the second resin layer 15, and the reinforcing fibrous substrate layer 11 and the second resin layer 15 can be formed at the same time.

Next, as shown in FIG. 12, a resin material for a first resin layer 13 is given onto the outer surface of the formed reinforcing fibrous substrate layer 11. Specifically, this is carried out by discharging the resin material from the resin discharge opening 25 and giving the resin material onto the outer surface of the reinforcing fibrous substrate layer 11, while the formed reinforcing fibrous substrate layer 11 and the second resin layer 15 are rotated by the rolls 21. Furthermore, at the same time, the given resin material is uniformly applied using the coater bar 23. Moreover, the resin material that constitutes each layer may be given as a mixture with the aforementioned inorganic filler(s).

Next, the applied resin material is to be dried and cured. This yields the wet paper transfer belt 1 in which the first resin layer 13, the reinforcing fibrous substrate layer 11 and the second resin layer 15 have been laminated in this order from the outer surface. Furthermore, the first plane 131 of the first resin layer 13 and/or the second plane 151 of the second resin layer 15 may be polished, using a polishing apparatus as necessary.

As above, the present invention has been explained in detail based on its preferred embodiments, though the present invention is not limited thereto, and each constituent can be substituted with any constituent that is capable of performing a similar function, or alternatively, any constituent can be added.

Moreover, in the aforementioned description, a wet paper transfer belt has been described as an example of a papermaking belt, though the present invention is not limited to it. For example, a papermaking belt of the present invention may be a shoe press belt, or may be a different papermaking belt.

EXAMPLES

Hereinbelow, the present invention will more specifically be described with examples, though the present invention is not to be limited to these examples.

1. Production of Wet Paper Transfer Belt

Example 1

A wet paper transfer belt according to Example 1 was produced by Front Surface Coating Penetration Method as follows:

(i) Preparation of Reinforcing Fibrous Substrate

First, as a reinforcing fibrous substrate a woven fabric of a warp backed weave pattern having the following constitution was prepared:

• • First Warp Yarns: Monofilament twist yarns of 3810 dtex consisting of polyamide 6.

(Two polyamide 6 monofilaments of 370 dtex were twisted together, and five sets of this were further twisted together. The primary twist was set at 2.1 twists/cm, and the final twist was set at 1.2 twists/cm.)

• • Second Warp Yarns: Multifilament twist yarns of 3396 dtex consisting of polyethylene terephthalate.

(One hundred and eighteen polyethylene terephthalate filaments of 8.5 dtex were parallelly arranged, and three sets of this were twisted together. The final twist was set at 0.1 twists/cm.)

• • Weft Yarns: Monofilament twist yarns of 1582 dtex consisting of polyamide 610.

(Two polyamide 610 monofilaments of 370 dtex were twisted together, and two sets of this were further twisted together. The primary twist was set at 3.1 twists/cm, and the final twist was set at 2.2 twists/cm.)

• • Weave Pattern: Top and bottom warp yarns, 35 warp yarns/5 cm; Weft yarns, 40 yarns/5 cm; a warp backed weave pattern (3/1 1/7, corresponding to the weave pattern in FIGS. 2 to 4).

(ii) Formation of Laminated Body

First, the prepared endless reinforcing fibrous substrate was hung over two parallelly placed rolls. At this time, the reinforcing fibrous substrate was hung over the rolls such that second warp yarns of the reinforcing fibrous substrate were in contact with the rolls. While rotating the rolls, a urethane composition was given onto a surface on which the first warp yarns of the reinforcing fibrous substrate were exposed. As the urethane composition, a mixture of a urethane prepolymer obtained by reacting a mixture of 2,4-tolylene-diisocyanate (2,4-TDI) and 2,6-tolylene-diisocyanate (2,6-TDI) with polytetramethylene ether glycol (PTMG) and dimethylthiotoluene diamine (DMTDA) as a curing agent were used.

When this urethane composition was given, the urethane composition was impregnated in the reinforcing fibrous substrate, and at the same time, it penetrated into the reinforcing fibrous substrate, forming the reinforcing fibrous substrate layer and the roll-side second resin layer at the same time. Next, a urethane composition of a first resin layer on each wet paper web carrying-side was given onto the outer surface of the formed reinforcing fibrous substrate layer to laminate the first resin layer. From this the outermost layer in order, a laminated body which would become the first resin layer, the reinforcing fibrous substrate layer and the second resin layer was heated and dried, yielding a semifinished product of a wet paper transfer belt.

(iii) Polishing and Buffing

A polishing paper cloth from #80 to #600 was set on a polishing apparatus as appropriate, and a wet paper web carrying-side surface of the wet paper transfer belt (semifinished product) was polished. Moreover, buffing was performed as appropriate in order to adjust the surface roughness of a wet paper web-contact surface, an arithmetic average roughness of a wet paper web carrying surface of the wet paper transfer belt of each example was set at from 0.3 to 20 μm. As above, the wet paper transfer belt according to Example 1 was completed.

The product dimension of the wet paper transfer belt was set at 20 m in length and 700 mm in width.

Example 2

A wet paper transfer belt according to Example 2 was produced in a similar manner to Example 1 except that the reinforcing fibrous substrate was changed as follows:

In the reinforcing fibrous substrate used in Example 2, second warp yarns, weft yarns and a fabric weave pattern similar to those in the reinforcing fibrous substrate used in Example 1 were used. On the other hand, first warp yarns used were as follows:

• • First Warp Yarns: Monofilament twist yarns of 2271 dtex consisting of polyamide 6.

(Two polyamide 6 monofilaments of 370 dtex were twisted together, and three sets of this were further twisted together. The primary twist was set at 2.7 twists/cm, and the final twist was set at 2.1 twists/cm.)

Example 3

A wet paper transfer belt according to Example 3 was produced in a similar manner to Example 1 except that the reinforcing fibrous substrate was changed as follows:

In the reinforcing fibrous substrate used in Example 3, first warp yarns, second warp yarns and a fabric weave pattern similar to those in the reinforcing fibrous substrate used in Example 1 were used. On the other hand, weft yarns used were as follows:

• • Weft Yarns: Monofilament single yarns of 1059 dtex consisting of polyamide 610.

Example 4

A wet paper transfer belt according to Example 4 was produced in a similar manner to Example 1 except that the reinforcing fibrous substrate was changed as follows:

In the reinforcing fibrous substrate used in Example 4, second warp yarns and a fabric weave pattern similar to those used in the reinforcing fibrous substrate used in Example 1 were used. On the other hand, first warp yarns and weft yarns used were as follows:

• • First Warp Yarns: Monofilament twist yarns of 2271 dtex consisting of polyamide 6.

(Two polyamide 6 monofilaments of 370 dtex were twisted together, and three sets of this were further twisted together. The primary twist was set at 2.7 twists/cm, and the final twist was set at 2.1 twists/cm.)

• • Weft Yarns: Monofilament single yarns of 1059 dtex consisting of polyamide 610.

Example 5

A wet paper transfer belt according to Example 5 was produced in a similar manner to Example 2 except that the reinforcing fibrous substrate was changed as follows:

In the reinforcing fibrous substrate used in Example 5, first warp yarns, second warp yarns and weft yarns similar to those in the reinforcing fibrous substrate used in Example 2 were used. On the other hand, it comprised as its fabric weave pattern a warp backed weave pattern (3/1 1/3, corresponding to the weave pattern in FIGS. 5 to 7).

Example 6

A wet paper transfer belt according to Example 6 was produced in a similar manner to Example 5 except that batt fibers were needled into both sides of the reinforcing fibrous substrate to form batt fiber layers.

In Example 6, short fibers of 22 dtex, cut length=76 mm, consisting of polyamide 66 was used as batt fibers. Batt fibers layers were formed on both sides such that the basis weight would be 100 g/m² on a side on which the first resin layer is to be formed (the wet paper web carrying-side), and 100 g/m² on a side on which the second resin layer is to be formed (roll-side).

Comparative Example 1

A wet paper transfer belt according to Comparative Example 1 was produced in a similar manner to Example 1 except that the reinforcing fibrous substrate was changed as follows:

• • First and Second Warp Yarns: Monofilament twist yarns of 2271 dtex consisting of polyamide 6.

(Two polyamide 6 monofilaments of 370 dtex were twisted together, and three sets of this were further twisted together. The primary twist was set at 2.7 twists/cm, and the final twist was set at 2.1 twists/cm.)

• • Weft Yarns: Monofilament twist yarns of 1582 dtex consisting of polyamide 610.

(Two polyamide 610 monofilaments of 370 dtex were twisted together, and two sets of this were further twisted together. The primary twist was set at 3.1 twists/cm, and the final twist was set at 2.2 twists/cm.)

• • Weave Pattern: Top and bottom warp yarns, 35 warp yarns/5 cm; Weft yarns, 40 yarns/5 cm; a warp backed weave pattern (3/1 1/3, corresponding to the weave pattern in FIGS. 5 to 7).

Moreover, in the reinforcing fibrous substrate, short fibers of 22 dtex, cut length=22 mm, consisting of polyamide 66 were used as batt fibers. Batt fiber layers were formed on both sides such that the basis weight would be 100 g/m² on a side on which the first resin layer is to be formed (the wet paper web carrying-side), and 100 g/m² on a side on which the second resin layer is to be formed (roll-side).

Comparative Example 2

A wet paper transfer belt according to Comparative Example 2 was produced in a similar manner to Example 1 except that the reinforcing fibrous substrate was changed as follows:

• • First Warp Yarns: Monofilament twist yarns of 2271 dtex consisting of polyamide 6. (Two polyamide 6 monofilaments of 370 dtex were twisted together, and three sets of this were further twisted together. The primary twist was set at 2.7 twists/cm, and the final twist was set at 2.1 twists/cm.)
  • Second Warp Yarns: Multifilament twist yarns of 3333 dtex consisting of polyamide 6.

(68 polyamide 6 filaments of 22.1 dtex were parallelly arranged and twisted together, and two sets of this were further twisted together. The primary twist was set at 0.7 twists/cm, and the final twist was set at 0.7 twists/cm.)

• • Weft Yarns: Monofilament single yarns of 1059 dtex consisting of polyamide 610.
  • Weave Pattern: Top and bottom warp yarns, 35 warp yarns/5 cm; Weft yarns, 40 yarns/5 cm; a warp backed weave pattern (3/1 1/7, corresponding to the weave pattern in FIGS. 2 to 4)

2. Evaluation

The produced wet paper transfer belts of Examples 1 to 6 and Comparative Examples 1 and 2 were evaluated for the status of development of warping at the end part according to the following procedures.

First, from each of the wet paper transfer belts of Examples 1 to 6 and Comparative Examples 1 and 2, a test piece S of 3.2 m in length and 22 cm in width was cut out. Next, in the room at the room temperature of 20±2° C. and humidity of 50±10%, each test piece S of Examples 1 to 6 and Comparative Examples 1 and 2 were immersed in water for 24 hours.

Next, the longitudinal end parts each of the test pieces S of Examples 1 to 6 and Comparative Examples 1 and 2 were sutured to form an annulus. Then, as shown in FIG. 13, each test piece S was hung over two parallelly placed rolls 30. Next, the rolls 30 were rotated, and the test piece S was run for two rounds at a speed of 4 m cloth/min, while spraying water 41 onto the surface of test piece by a spraying apparatus 40.

After spraying, a tensile force acting on the test piece S was adjusted to 5 kN/m, and thereafter the rolls 30 were stopped. Then, as shown in FIG. 14, the second resin layer-side of the test piece S was brought into contact with a carpenter's square 50, and the carpenter's square 50 was adjusted to be made horizontal, and the distance between the carpenter's square 50 and a part of the test piece S that is at the farthest from the carpenter's square 50 was measured as selvage curl distance d₁ and d₂. Note that, the end part of the test piece S might warp towards the roll-side, i.e., the carpenter's square 50-side. In this case, the distance between the highest part of the test piece S near the center in the width direction and the carpenter's square 50 was measured as the selvage curl distance. The selvage curl distance was measured for four parts, their average was taken as the selvage curl distance of the test piece S.

The results of the evaluation above are shown in Tables 1 and 2 with the constitution of each of the reinforcing fibrous substrates of Examples 1 to 6 and Comparative Examples 1 and 2.

TABLE 1
			Example 1	Example 2	Example 3	Example 4
Reinforcing	1st Warp Yarns	Material	Polyamide 6	Polyamide 6	Polyamide 6	Polyamide 6
Fibrous		Type	Monofilament	Monofilament	Monofilament	Monofilament
Substrate			twist yarns	twist yarns	twist yarns	twist yarns
		Fineness (dtex)	3810	2271	3810	2271
	2nd Warp Yarns	Material	Polyethylene	Polyethylene	Polyethylene	Polyethylene
			terephthalate	terephthalate	terephthalale	terephthalate
		Type	Multifilament	Multifilament	Multifilament	Multifilament
			twist yarns	twist yarns	twist yarns	twist yarns
		Fineness (dtex)	3396	3396	3396	3396
	Weft Yarns	Material	Polyamide 610	Polyamide 610	Polyamide 610	Polyamide 610
		Type	Monofilament	Monofilament	Monofilament	Monofilament
			twist yarns	twist yarns	single yarns	single yarns
		Fineness (dtex)	1582	1582	1059	1059
	Fabric Weave Pattern	3/1 1/7	3/1 1/7	3/1 1/7	3/1 1/7
	Number of Crossing Points of 1st Warp	16	16	16	16
	Yarns and Weft Yarns
	Number of Grossing Points of 2nd Warp	8	8	8	8
	Yarns and Weft Yarns
Batt Fiber	Wet Paper Web Carrying (1st Resin)-Side	Non	Non	Non	Non
Layer	Roll (2nd Resin)-Side	Non	Non	Non	Non
Evaluation	Selvage Curl Distance (mm)	4.3	4.8	7.1	8.8

TABLE 2
					Comparative	Comparative
			Example 5	Example 6	Example 1	Example 2
Reinforcing	1st Warp Yarns	Material	Polyamide 6	Polyamide 6	Polyamide 6	Polyamide 6
Fibrous		Type	Monofilament	Monofilament	Monofilament	Monofilament
Substrate			twist yarns	twist yarns	twist yarns	twist yarns
		Fineness (dtex)	2271	2271	2271	2271
	2nd Warp Yarns	Material	Polyethylene	Polyethylene	Polyamide 6	Polyamide 6
			terephthalate	terephthalate
		Type	Multifilament	Multifilament	Multifilament	Multifilament
			twist yarns	twist yarns	twist yarns	twist yarns
		Fineness (dtex)	3396	3396	2271	3333
	Weft Yarns	Material	Polyamide 610	Polyamide 610	Polyamide 610	Polyamide 610
		Type	Monofilament	Monofilament	Monofilament	Monofilament
			twist yarns	twist yarns	twist yarns	single yarns
		Fineness (dtex)	1582	1582	1582	1059
	Fabric Weave Pattern	3/1 1/3	3/1 1/3	3/1 1/3	3/1 17
	Number of Crossing Points of 1st Warp	4	4	4	16
	Yarns and Weft Yarns
	Number of Crossing Points of 2nd Warp	4	4	4	8
	Yarns and Weft Yarns
Batt Fiber	Wet Paper Web Carrying (1st Resin)-Side	Non	Present	Present	Non
Layer	Roll (2nd Resin)-Side	Non	Present	Present	Non
Evaluation	Selvage Curl Distance (mm)	8.1	13.0	18.5	19.3

As shown in Tables 1 and 2, in the wet paper transfer belts according to Examples 1 to 6, the selvage curl distance was smaller and the warping at the end part was suppressed, as compared to the wet paper transfer belts according to Comparative Examples 1 and 2. In the evaluation mentioned above, a test piece S of 22 cm in width was used, though a wet paper transfer belt to be hung into the actual papermaking machine would have a width of several meters, and the warping at its end part would become greater almost in proportion thereto.

When comparing Example 1 to Example 2, and Example 3 to Example 4, respectively, in the wet paper transfer belts according to Examples 1 and 3 in which the fineness of the first warp yarns on the wet paper web carrying-side was greater than the fineness of the second warp yarns on the roll-side, the selvage curl distance was smaller and the warping at the end part was suppressed as compared to the wet paper transfer belts according to Examples 2 and 4 in which the fineness of the first warp yarns on the wet paper web carrying-side were smaller than the fineness of the second warp yarns on the roll-side.

Furthermore, comparing Example 1 to Example 3, and Example 2 to Example 4, respectively, in the wet paper transfer belts according to Examples 1 and 3 in which the monofilament twist yarn was used as the weft yarns, the selvage curl distance was smaller and the warping at the end part was suppressed as compared to the wet paper transfer belts according to Examples 2 and 4 in which the monofilament single yarns were used as the weft yarns.

Moreover, comparing Example 2 to Example 5, in the wet paper transfer belt according to Example 2 in which the reinforcing fibrous substrate having a 3/1 1/7 fabric weave pattern was used, the selvage curl distance was smaller as compared to the wet paper transfer belt according to Example 5 in which the reinforcing fibrous substrate having a 3/1 1/3 fabric weave pattern was used.

Moreover, comparing Example 5 to Example 6, in the wet paper transfer belt according to Example 5 in which the reinforcing fibrous substrate did not have a batt fiber layer, the selvage curl distance was smaller as compared to the wet paper transfer belt according to Example 6 in which the reinforcing fibrous substrate comprised a batt fiber layer. On the other hand, also in the wet paper transfer belt according to Example 6 in which the reinforcing fibrous substrate comprised the batt fiber layer, the selvage curl distance was smaller and the warping at the end part was suppressed as compared to the wet paper transfer belts according to Comparative Examples 1 and 2.

REFERENCE SIGNS LIST

• • 1, 1A, 1B wet paper transfer belt (papermaking belt)
  • 11, 11B the reinforcing fibrous substrate layer
  • 111, 111A, 111B reinforcing fibrous substrate
  • 113 resin
  • 115, 115A first warp yarn
  • 117, 117A second warp yarn
  • 119, 119A weft yarn
  • 13, 13B first resin layer
  • 131, 131B first plane (a wet paper web-contact surface)
  • 15, 15B second resin layer
  • 151, 151B second plane (roll contact surface)

Claims

1. A papermaking belt that is used in a papermaking machine and that comprises a first plane on which a wet paper web is placed and a second plane on the opposite side to the first plane, wherein: the papermaking belt comprises a reinforcing fibrous substrate layer comprising at least one layer of a woven fabric,at least one layer of said woven fabric comprises a double or more combination weave pattern,said combination weave pattern comprises first yarns and second yarns that are placed in parallel;said first yarns are placed closer to the first plane-side than said second yarns and said second yarns are placed closer to the second plane-side than said first yarns; andsaid second yarns comprise a polyester yarn.

2. The papermaking belt according to claim 1, wherein said second yarn are crimped yarns.

3. The papermaking belt according to claim 1, wherein said second yarns are multifilament twist yarn.

4. The papermaking belt according to claim 1, wherein said first yarns and said second yarns are placed in the machine direction of the papermaking belt.

5. The papermaking belt according to claim 1, comprising no batt fiber layer.

6. The papermaking belt according to claim 1, wherein the fineness of said first yarns is greater than the fineness of said second yarns.

7. The papermaking belt according to claim 1, wherein: said woven fabric further comprises third yarns that are woven into said first yarns and said second yarns; andsaid third yarns are monofilament twist yarns.

8. The papermaking belt according to claim 1, wherein: said woven fabric comprising said combination weave pattern further comprises third yarns that are woven into said first yarns and said second yarns; andsaid combination weave pattern is a weave pattern that comprises a repeat unit that is capable of concurrent formation of a repeat in which each said third yarn passes through K said first yarns on the side of said first plane while it passes through L said first yarns on the side of said second plane and a repeat in which each said third yarn passes through M said second yarns on the side of said first plane while it passes through N said second yarns on the side of said second plane;wherein the relation K/L≥N/M is satisfied.

9. The papermaking belt according to claim 1, wherein: said woven fabric comprising said combination weave pattern further comprises third yarns that are woven into said first yarns and said second yarns, andthe number of crossing points of said first yarns and said third yarns in a weave repeat is greater than the number of crossing points of said second yarns and said third yarns in the weave repeat.

10. The papermaking belt according to claim 1, wherein the papermaking belt is a wet paper transfer belt.

11. The papermaking belt according to claim 1, wherein the papermaking belt is a shoe press belt.