Patent Application
20250198084
The present invention relates to a base fabric for papermaking felt and papermaking felt made by jointing same.
Conventionally, in the press section of a papermaking machine, water squeezing work from wet paper is carried out using a press felt and a pair of press rolls, or a press roll and a shoe press. For this press felt, one having ends with seam loops as shown in
For such press felt, press felts having a seam loop part around which stuffer yarns are inserted in order to attempt preventing hair loss of batting fibers and reducing resistance from core wire insertion are known (Patent Literatures 1 to 4).
On the other hand, it has been reported that press felts having seam loop parts might cause marks on a sheet on a paper after dehydration (Patent Literature 2).
An object of the present invention is to provide a base fabric for papermaking felt having a seam loop part that is able to minimize the occurrence of seam marks on the paper after dehydration.
In the course of intensive research to solve the above problem, the inventors found that, on a base fabric for papermaking felt having a seam loop part, it is possible to minimize the occurrence of seam marks by inserting one or more hydrophilic stuffer yarns near the outer side of one seam loop part and the inner side of other seam loop part or near the outer side of one seam loop part and the inner and outer sides of the other seam loop part. The present invention was completed as a result of further research.
That is, the present invention relates to followings.
<1> A base fabric for papermaking felt having a wet-paper-side layer on which a wet-paper-side surface is formed, a roll-side layer on which a roll-side surface is formed, and, at both ends, seam loop parts which connect the wet-paper-side layer and the roll-side layer and through which core wires are passed in the CD direction,
<2> The base fabric for papermaking felt according to <1>, wherein the hydrophilic yarns are fiber having a moisture content of 6% or more at a relative humidity of 65% and 20° C. (standard state).
<3> The base fabric for papermaking felt according to <1> or <2>, wherein the hydrophilic yarns are rayon or hydrophilically treated nylon.
<4> A papermaking felt, which is made by jointing the base fabric for papermaking felt according to any one of <1> to <3>.
It is possible to minimize the occurrence of seam marks on paper after dehydration by using the base fabric for papermaking felt of the present invention.
The mechanism by which occurrence of seam marks on paper after dehydration can be minimized is not necessarily clear, but it is thought that there is a difference in water absorption between base fabric and seam loop part, and therefore water that moves from wet paper is not dehydrated uniformly, which is a cause of occurrence of the seam marks. Then, by inserting one or more hydrophilic stuffer yarns near the outer side of one seam loop part and the inner side of other seam loop part or near the outer side of one seam loop part and the inner and outer sides of the other seam loop part, it is expected to compensate the difference in water absorption between the base fabric and the seam loop part, and the water that moves from wet paper can be dehydrated uniformly to minimize the occurrence of seam marks on paper after dehydration.
The base fabric for papermaking felt of the present invention is the one which has a wet-paper-side layer on which a wet-paper-side surface is formed, a roll-side layer on which a roll-side surface is formed, and, at both ends, seam loop parts which connect the wet-paper-side layer and the roll-side layer and through which core wires are passed in the CD direction, and the wet-paper-side layer and the roll-side layer are made of MD yarns material in the running direction of the felt (MD direction) and CD yarns material in the transverse direction of the felt (CD direction), the seam loop parts are formed of MD yarns material, the base fabric for papermaking felt further includes one or more stuffer yarns passed through near the outer side of one seam loop part and on the inner side of other seam loop part or near the outer side of one seam loop part and on the inner and outer sides of the other seam loop part, and the stuffer yarns are hydrophilic yarns.
The base fabric for papermaking felt of the present invention is the one which has a wet-paper-side layer on which a wet-paper-side surface is formed, a roll-side layer on which a roll-side surface is formed, and, at both ends, seam loop parts which connect the wet-paper-side layer and the roll-side layer and through which core wires are passed in the CD direction. The wet-paper-side layer and the roll-side layer are made of MD yarns material in the running direction of the felt (MD direction) and CD yarns material in the transverse direction of the felt (CD direction), and the seam loop parts are formed of MD yarns material.
The base fabric for papermaking felt of the present invention further includes one or more stuffer yarns passed through near the outer side of one seam loop part and on the inner side of other seam loop part or near the outer side of one seam loop part and on the inner and outer sides of the other seam loop part.
The stuffer yarns of the present invention are hydrophilic yarns. In the present invention, the “hydrophilic yarns” refer to yarns that can effectively absorb water that moves from the wet paper to the base fabric for papermaking felt. When the stuffer yarns are hydrophilic yarns, it is possible to minimize the occurrence of seam marks on the paper after dehydration. The hydrophilic yarns are fibers having a moisture content of preferably 6% or more, more preferably 8% or more, and even more preferably 10% or more, at a relative humidity of 65% and 20° C. (standard state).
On the other hand, when the stuffer yarns are not hydrophilic yarns, seam marks are likely to occur on the paper after dehydration.
Hydrophilic yarns include, but are not limited to, rayon (moisture content: approximately 11%), hydrophilically treated nylon (moisture content: approximately 20%), wool (moisture content: approximately 16%), cupra (moisture content: approximately 12 to 14%), hemp (moisture content: approximately 7 to 10%), silk (moisture content: approximately 9%), and cotton (moisture content: approximately 7%), etc. Here, the “hydrophilically treated nylon” refers to nylon of which moisture content is adjusted to approximately 20% by attaching water-absorbing resin to nylon that is not hydrophilic yarns. The water-absorbing resin is a resin with hydrophilic group having hydroxyl group, carboxyl group, or amino group etc., and includes, for example, urethane, cellulose, and acrylic resin. Rayon and hydrophilically treated nylon are preferred as the hydrophilic yarns from the viewpoints of minimization of the occurrence of seam marks and sustainability with washability (chemical resistance).
The number of stuffer yarns may be one or more, and is not particularly limited as long as the occurrence of seam marks can be minimized. One stuffer yarn may be inserted alone or a plurality of yarns twisted together may be inserted. Alternatively, a plurality of yarns may be inserted into a plurality of locations, for example, one yarn may be inserted into one location, three yarns twisted together may be inserted into another location.
Each of the stuffer yarns are inserted in CD direction, near the outer side of one seam loop part and on the inner side of other seam loop part or near the outer side of one seam loop part and on the inner and outer sides of the other seam loop part, and an embodiment in which the stuffer yarn(s) is(are) woven into MD yarns material in wet-paper-side layer, an embodiment in which it(they) is(are) inserted straight into the middle of wet-paper-side layer and roll-side layer and an embodiment in which it(they) is(are) woven into MD yarns material in roll-side layer are included, but not particularly limited as long as the occurrence of seam marks can be minimized. In addition, a weaving pattern when the stuffer yarns are woven into the MD yarns material of the wet-paper-side layer or the roll-side layer include 1/1 plain, 2/1 twill, 3/1 twill, 4/1 twill, 5/1 twill, 6/1 twill, 7/1 twill, etc., but is not particularly limited as long as the occurrence of seam marks can be minimized.
There are no particular limitations on a method for producing the base fabric for papennaking seam felt of the present invention. Typically, it is obtained by weaving MD yarns that are weft yarns on the loom and CD yarns that are warp yarns on the loom by a loom, and the MD yarns are entangled with core wires at the end of the base fabric to form loops to obtain an endless-form fabric.
Further, the present invention also relates to a papermaking felt made by jointing the above base fabric for papermaking felt. Preferred embodiments of such papermaking felt are the same as those described about the base fabric for papermaking felt.
Hereinafter, a papermaking felts which is made by jointing a base fabric for papennaking felt of the present invention will be described in detail with examples, but these are not limiting the present invention in any way.
1590 d rayon spun yarns made by twisting three 530 d yarns was woven onto MD yarns material on wet-paper-side layer of base fabric in a 1/1 plain weaving pattern, and 1500 d nylon spun yarns was woven onto MD yarns material on roll-side layer of the base fabric in 1/1 plain weaving pattern.
After weaving the base fabric, the fiber layer was laminated and integrated by needling to form a felt, in addition, the protective core wire for needling was pulled out and the fiber layers above the loop were cut and separated to obtain base fabric for papermaking felt of Example 1.
Base fabric for papermaking felts for the Examples 2 to 3 and for the Comparative Example 1 were obtained by same method as described in the production of the base fabric for papermaking felt of Example 1 except for that for Example 2, 1500 d nylon spun yarns was woven onto MD yarns material on wet-paper-side layer of the base fabric in a 1/1 plain weaving pattern, and 1590 d rayon spun yarns made by twisting three 530 d yarns was woven onto the MD yarns material on roll-side layer of the base fabric in a 1/1 plain weaving pattern, that for Example 3, 1500 d nylon spun yarns, hydrophilically treated by adhering water absorptive resin, which is specifically urethane-based water absorptive resin coated, was woven onto the MD yarns material on wet-paper-side layer of the base fabric in a 1/1 plain weaving pattern, and that for Comparative Example 1, 1500 d nylon spun yarns was woven onto MD yarns material on wet-paper-side layer of the base fabric in a 1/1 plain weaving pattern.
1500 d nylon spun yarns was woven onto MD yarns material on wet-paper-side layer of the base fabric in a 1/1 plain weaving pattern, 1500 d nylon spun yarns was woven onto MD yarns material on roll-side layer of the base fabric in a 1/1 plain weaving pattern, and a 1770 d rayon spun yarns made by twisting ten 177 d yarns was inserted straight into the middle of the wet-paper-side layer and the roll-side layer without being entangled with either the CD yarns material and the MD yarns material.
After weaving the base fabric, the fiber layers were laminated and integrated by needling to form a felt, in addition, the protective core wire for needling was pulled out and the fiber layers above the loop were cut and separated to obtain base fabric for papermaking felt of Example 4.
Base fabric for papermaking felts for the Examples 5 to 7 and for the Comparative Example 2 were obtained by same method as described in the production of the base fabric for papermaking felt of Example 4 except for that for Example 5, 885 d rayon spun yarns made by twisting five of 177d yarns was inserted straight into the middle of wet-paper-side layer and roll-side layer, that for Example 6, 1500 d nylon spun yarns, hydrophilically treated by adhering water absorptive resin, which is specifically urethane-based water absorptive resin coated, was inserted straight into the middle of wet-paper-side layer and roll-side layer, that for example 7, 800 d wool was inserted straight into the middle of wet-paper-side layer and roll-side layer, and that for Comparative Example 2, 800 d twist-less yarns was inserted straight into the middle of wet-paper-side layer and roll-side layer.
In addition, the rayon spun yarns used in Examples 1 to 7 and Comparative Examples 1 to 2 (moisture content of approximately 11% at relative humidity of 65% and 20° C. (standard state)), the hydrophilically treated nylon spun yarns (approximately 20% at the same condition) and the wool (approximately 16% at the same condition) are hydrophilic yarns. On the other hand, the nylon spun yarns (approximately 5% at the same condition) and the nylon twist-less yarns (approximately 5% at the same condition) are not hydrophilic yarns.
For the base fabrics for papermaking felt of Examples 1 to 7 and Comparative Examples 1 to 2, a core wire with five monofilaments of 0.35 mm in diameter was inserted into the seam part to obtain papermaking felts of Examples 1 to 7 and Comparative Examples 1 to 2, respectively.
Samples were punched out from the base fabrics for papermaking felt of Examples 1 to 7 and Comparative Examples 1 to 2, in a circular shape with a diameter of 70 mnm so that the seam part is centered, to obtain samples for evaluation of Examples 1 to 7 and Comparative Examples 1 to 2.
Samples of Examples 1 to 7 and Comparative Examples 1 to 2 were produced and evaluated according to following procedure.
d)
d)
indicates data missing or illegible when filed
In Examples 4 and 3 in which rayon spun yarns or hydrophilically treated nylon spun yarns, which was hydrophilic y yarns, was woven into the MD yarns material of the wet-paper-side layer, the occurrence of seam marks was minimized compared to Comparative Example 1, in which nylon spun yarns, which was not hydrophilic yarns, was woven into the same position. In addition, in Example 2, in which rayon spun yarns, which was hydrophilic yarns, was woven into the MD yarns material of the roll-side layer, the occurrence of seam marks was minimized compared to Comparative Example 1, in which nylon spun yarn, which was not hydrophilic yarns, was woven into the same position. Furthermore, also in Examples 4 to 7, in which rayon spun yarns, hydrophilically treated nylon spun yarns, or wool, in which hydrophilic yarns, was inserted into the middle of the wet-paper-side layer and the roll-side layer, the occurrence of seam marks was minimized compared to Comparative Example 2, in which nylon spun yarns, which was not hydrophilic yarns, was inserted into the same position.
By using the base fabric for papermaking felt of the present invention, it is possible to minimize the occurrence of seam marks on paper after dehydration.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-213400 | Dec 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/047844 | 12/26/2022 | WO |
