The present invention relates to the technical field of composite materials comprising a warp-knitted textile panel, preferably including weft-inserted weft yarns, and coated on at least one of its faces with a layer of at least one polymer material.
Warp-knitted textile panels are thus used as reinforcement for the layer of at least one polymer material. These composite materials may be used as a protective cover, e.g. for swimming pools, as an advertising medium, as a luggage cover, as a roofing element, in particular for terraces, or as a self-adhesive strip. For a self-adhesive strip, the textile panel includes a film that is suitable for coming into contact with the adhesive layer without adhering to it.
A self-adhesive strip is known that includes a warp-knitted textile panel having weft yarns inserted at regular intervals. A drawback of that knitted panel is that it presents first and second opposite faces that are uneven. The lack of planeness of those faces makes it necessary to use a relatively large amount of polymer material in order to even out the faces and to obtain a composite material that is homogeneous. Furthermore, the shape of the wales of the knitted panel is visible in the adhesive layer, and that gives an unattractive aspect to the composite material.
This aspect may considerably hamper use of this type of knitted panel, which consists of composite material having a decorative function, such as for protective covers for swimming pools, luggage covers, advertising media, or roofing elements. Specifically, the wales create a stripy effect on the surface of composite material.
EP 0 978 583 A1 relates to an article having loops projecting from its surface suitable for acting as female fastener members in a fastener device of the hook and loop type. As shown in FIGS. 9 to 11 in particular, the wales are formed by means of two guide bars of a knitting machine working at the same time and on each course and not in alternation in such a manner that the first yarn and the second yarn form stitches on each of the courses and not on every other course. The wales present loops at regular intervals and thus form bulky projections. The surface of the material including those wales is therefore not even and plane and takes away a large amount of any polymer material layer that is applied to said surface, and does so in uneven manner.
The present invention thus provides a warp-knitted textile panel having first and second faces presenting planeness and uniformity that are improved, limiting the stripy effect of the wales in the layer of at least one polymer material, while satisfying the criteria for strength in the warp and weft directions in order to provide its primary function of reinforcement.
In a first aspect, the present invention provides a composite material comprising a warp-knitted textile panel having wales corresponding to the warp direction and courses corresponding to the weft direction and first and second opposite faces, said first face being covered with a layer of at least one polymer material. Advantageously, each of said wales includes first stitches formed on every other course with a first yarn, and second stitches formed on every other course with a second yarn, the first and second stitches being alternated on every other course and being in opposite directions. In addition, in the weft direction, the first yarn and the second yarn each form stitches on every other course in alternation, and said textile panel includes weft yarns inserted in the weft direction on every n out of p courses, n and p being integers, with n being less than or equal to p.
Advantageously, using two yarns to form the first and second alternate stitches on a wale, on every other course, makes it possible to halve the fineness of the single knit yarn used in the warp-knitted textile panels of the prior art and thus to improve the planeness and the uniformity of the textile panel. Furthermore, the thickness of said knitted panel is also reduced. Advantageously, the strength of the knitted panel of the invention is substantially of the same order as that of prior art panels, since the overall fineness of knit yarn found in each wale for the panel of the invention is equal to the fineness of the single knit yarn in the prior art panel.
In addition, the characteristic according to which the first and second stitches are alternated and in opposite directions makes it possible to balance the sinker stitches and thus to improve planeness and geometrical uniformity of the wales.
Furthermore, the first yarn forms stitches on every other course and thus the second yarn does not form stitches thereon, and that improves planeness and uniformity of the knitted panel.
The warp-knitted textile panel of the invention is thus improved in order to receive a layer of at least one polymer material at least on its first face, the resulting composite has a more even surface state and has better planeness, which also makes it possible to reduce the amount of said layer, and therefore represents a substantial saving on the finished composite.
The weft yarns may be multifilament yarns and/or monofilament yarns, preferably multifilament yarns. The composition of the weft yarns is a function of the purpose of the composite material.
Preferably, the weft yarns are inserted in the range every course to one course in every four, in particular in the range every course to every other course.
Depending on the knit weave, the weft yarns make it possible to assemble the wales together, in order to improve the strength of the knitted textile panel and to control the size of the openings made in the panel as a function of the number of weft yarns inserted per centimeter in the warp direction.
Preferably, the number of weft yarns inserted per centimeter (cm) in the warp direction lies in the range 1 yarn/cm to 25 yarns/cm, preferably in the range 1 yarn/cm to 18 yarns/cm.
Preferably, the number of stitches in the weft direction of the warp-knitted textile panel lies in the range 6 wales/inch to 46 wales/inch, more preferably in the range 6 wales/inch to 40 wales/inch.
By definition, a weft yarn does not form a stitch but is simply inserted in the weft direction so as to be substantially perpendicular to the warp direction.
In the present text, the term “knitting guide bar” is used to refer to a needle guide bar of a knitting machine. The knitting machine used in the context of the invention therefore works with at least two needle guide bars working in alternation. Thus, when a needle guide bar supporting the first yarn is working, the other needle guide bar supporting the second yarn is not working, the first and second stitches are thus obtained in alternation as defined in the invention.
The first and second stitches may be open or closed stitches.
Preferably, in the meaning of the present invention, “a layer of at least one polymer material” should be understood as referring to any continuous or discontinuous layer. The term “discontinuous layer” should be understood as being a layer comprising said polymer material arranged in discontinuous manner in patterns that may optionally be arranged in regular manner on said first face, e.g. in dots, in columns, or in any other geometrical pattern.
The term “continuous layer” should be understood as being a layer of optionally uniform thickness that is applied on the entire first face of the textile panel.
Said layer of the invention may be applied on the first face and/or on said second face of the textile panel by means of any technique known to the person skilled in the art, and in particular by knife coating, point coating, spraying, laminating said layer, or also impregnation.
Said at least one polymer material of the layer applied on the first face of the textile panel may be the same or different from said at least one polymer material of the layer applied on the second face of the textile panel.
Preferably, when the first face and the second face of the textile panel are each covered with the same layer comprising at least one polymer material, the textile panel is embedded in said layer.
The first and second yarns may be multifilament yarns and/or monofilament yarns, preferably multifilament yarns.
The compositions of the first and second yarns are determined as a function of the purpose of the composite material.
In addition, said at least one polymer material in said layer is determined as a function of the purpose of the composite material.
The warp-knitted panel of the invention may be knitted on a tricot warp knitting machine with weft insertion, a Raschel knitting machine with weft insertion, or also a crocheting machine.
Preferably, the textile panel of the invention is substantially plane, in particular flat knitted.
Said layer of at least one polymer material may include various additives such as pigments, or fillers, e.g. titanium dioxide.
In a variant, said warp-knitted textile panel includes first and second stitches, which form chain-stitches and extend along a wale.
In this event, it is necessary to provide weft yarns inserted in the stitches of the first and second stitches in order to gather the wales together. This arrangement is preferred for manufacturing knitted panels having openwork, in particular having at least one dimension of 1 millimeter (mm) or more.
Advantageously, this arrangement makes it possible to manufacture textile panels that are breakable manually in at least one direction, i.e. in the warp direction and/or in the weft direction.
Moreover, the fact that there are no tricot stitches in said panel further improves planeness. Indeed, the weft yarns providing the connection between the wales have a substantially rectilinear direction, since they pass through the stitches of the courses. In contrast, when the yarns of the tricot stitches extend along at least two adjacent wales so as to connect the wales together, they do not have a rectilinear path because they are knitted.
Said chain stitches may be open or closed stitches.
In an alternative, the first stitches are chain stitches and the second stitches are tricot stitches extending along at least two adjacent wales.
In this event, since the second stitches extend along at least two wales, the weft yarns are not necessary for assembling the wales together. However, the weft yarns may be inserted if it is desired to improve the strength of the knitted panel.
In advantageous manner, it should also be observed that the weft yarns provide more elasticity to the knitted textile panel when tricot stitches are present. Indeed, when the layer of at least one polymer material is placed on the first face of the textile panel, the shrinkage behavior during the heat treatment of the assembly formed by said layer and said panel is uniform. Indeed, the textile panel shrinks to match the shrinkage of the layer of at least one polymer material, which improves cohesion and facilitates assembly of the composite material of the invention.
Said chain stitches may be open or closed stitches.
In an alternative, the first and second stitches are tricot stitches extending along at least two adjacent wales.
The above-described technical effect concerning the behavior on shrinkage of the composite material is also found in this variant.
In this event, since the first and second stitches extend along at least two wales, the weft yarns are not necessary for assembling the wales together. The weft yarns may however be inserted if it is desired to improve the strength of the knitted panel.
In a variant, the number of stitches in the warp direction of the warp-knitted textile panel lies in the range 1 stitch/cm to 25 stitches/cm, preferably in the range 1 stitch/cm to 18 stitches/cm.
In a variant, the first yarn, the second yarn, and possibly the weft yarn, are multifilament yarns and/or monofilament yarns, preferably selected independently from among: polyethylene terephthalate (polyester); polyamide 6-6; polyamide 4-6; polyamide 6; polyethylene; polypropylene; polyacrylic; polypropylene.
In a variant, the first yarn, the second yarn, and possibly the weft yarn, have a fineness that is greater than or equal to 7 decitex (dtex) and less than or equal to 3000 dtex, more preferably greater than or equal to 10 dtex.
Preferably, the fineness of the first, second, and third yarns is greater than or equal to 22 dtex and less than or equal to 1000 dtex.
In a variant, the layer comprises at least one polymer material selected from the list including: polyurethane; polyethylene terephthalate (polyester); polyamide 6-6; polyamide 6; polyamide 4-6; polyvinyl chloride; a fluorinated polymer, such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF); ethylene-vinyl acetate (EVA).
In a second aspect, the present invention provides a method of manufacturing a composite material according to any of the above-described variants, comprising the following steps:
a) a step of knitting a warp-knitted textile panel having first and second opposite faces, and wales and courses, on a knitting machine having two guide bars, each respectively supporting a first yarn and a second yarn in order to knit each wale, the two guide bars working in alternation and in opposite directions so that each of said wales comprises first stitches formed on every other course with a first yarn, and second stitches formed on every other course with a second yarn, the first and second stitches being alternated on every other course and in opposite directions, in the weft direction, the first yarn and the second yarn each form stitches on every other course in alternation, and said textile panel (11, 17, 20, 23, 27, 28) includes weft yarns (26) inserted in the weft direction on every n out of p courses, n and p being integers, with n being less than or equal to p;
b) a step of coating one of said faces of said textile panel in a layer comprising at least one polymer material.
In a variant, the method includes a step of inserting weft yarns in the weft direction at every n out of p courses, n and p being integers, with n being less than or equal to p.
Preferably, the first and second stitches extend along a wale.
Preferably, the first and second stitches are open or closed chain stitches in opposite directions.
In a third aspect, the present invention provides a self-adhesive strip that is breakable manually in at least one direction, the strip including a composite material according to any of the above-described variants, in particular in the first and/or second aspect of the invention, comprising a warp-knitted textile panel having first stitches and second stitches extending along a wale and including weft yarns inserted in the weft direction at regular intervals on every n out of p courses, n and p being integers with n being less than or equal to p, said layer comprises at least one self-adhesive polymer material, and the second face of said knitted textile panel, possibly covered with said layer, is covered with a plastics film.
The strip of interlining has longitudinal and transverse directions, said strip being breakable in at least one of these directions, preferably in the transverse direction.
Preferably, the first and second faces of said textile panel are covered with said layer comprising at least one self-adhesive polymer material, in particular so that said panel is embedded in said layer.
In another variant, when the second face is also covered with a layer of at least one polymer material, said polymer material may be the same or different from at least one polymer material of the layer covering the first face of the textile panel.
In the present invention, the term “plastics film” should be understood as referring to any synthetic film suitable for coming into contact with said layer of self-adhesive polymer material without adhering thereto. Said plastics film may thus be made of polyethylene terephthalate, vinyl polychloride, polypropylene, or also polyethylene, or also silicone, e.g. said silicone film forms part of a silicone treated paper.
Said self-adhesive polymer material may be a polyacrylic adhesive and in general be made from any material known to the person skilled in the art that is suitable for acting as a self-adhesive polymer, e.g. polyurethane.
Said self-adhesive polymer material may be an adhesive that is permanent or it may be repositionable.
In a sub-variant, the textile panel is covered along a first face of a layer comprising at least one permanent self-adhesive polymeric material and along a second face of a layer comprising at least one repositionable self-adhesive polymer material.
Preferably, the first face and/or the second face is/are covered with a plastics film, in particular with a silicone treated paper.
In a fourth aspect, the present invention provides a strip of interlining comprising a composite material according to any of the above-described variants, said layer comprising at least one thermofusible polymer material.
A strip of interlining is generally used when making items of clothing to give strength to a particular area of the item, such as the collar, to assemble textile panels together, or to hide seam zones.
Said thermofusible polymer material may be any polymer material known to the person skilled in the art and suitable for melting under the effect of heat. For example, said thermofusible polymer material may be a polyamide 6 polymer or also a polyamide 6-6 polymer.
In a fifth aspect, the present invention provides a strip of interlining comprising a composite material according to any of the above-described variants, said layer comprising at least one self-adhesive polymer material.
Said self-adhesive material may be an adhesive, such as a polyacrylic adhesive.
In a sixth aspect, the present invention provides: a protective cover; an advertising medium; a luggage cover; or a roofing unit including a composite material according to any of the above-mentioned alternative embodiments, having said layer comprising at least one polymer material that is resistant to abrasion, the textile panel being embedded in said layer so that its first and second faces are covered with said layer. The second face of said textile panel is advantageously water-resistant.
Said layer of at least one polymer material may thus be dope pigmented by adding one or more polymer pigments or dyes before being applied to said knitted textile panel.
Said layer of at least one polymer material may also be printed, in particular for advertising media, for example by inkjet printing.
The layer of at least one polymer material possibly comprises polyvinyl chloride, and may be applied by scraper to said textile panel. Depending on its purpose, the textile panel covered with said layer may further be covered on its first and/or second face with a plastics film.
The
The
By way of non-limiting example, a warp-knitted textile panel of the prior art obtained by implementing the knit weave shown in
The first example of a warp-knitted panel of the invention having a knit weave 11 that is shown in
In
In
The knit weaves 11, 17, 20, and 23 comprise first and second stitches extending along only one wale at the same time so that weft yarns 26 are necessary in order to assemble the wales of the textile panels together resulting therefrom and in order to improve the strength of said panels.
The knit weaves 27 and 28 shown in
In the examples shown in
In a precise example, given by way of non-limiting example, a warp-knitted textile panel obtained by implementing any of the knit weaves 11, 17, 20, or 23 using first and second multifilament yarns of 25 dtex each, and a multifilament weft yarn of 167 dtex, presents thickness of about 115 μm for a weight/m2 of 11 g/m2. The textile panel of the invention thus has thickness that is reduced by 30% relative to the thickness of 168 μm of a prior art panel.
The implementation of the warp-knitted textile panel of the invention obtained in this way as a manually breakable self-adhesive strip requires only approximately 33 g/m2 of a layer of adhesive polymer material compared to 45 g/m2 for a warp-knitted textile panel of the prior art. The uniformity of the first and second faces of the textile panel of the invention makes it possible, at equivalent strengths, to improve the surface state of the textile panel and consequently to reduce the amount of the layer of polymer material, made of self-adhesive polymer in this precise example.
Number | Date | Country | Kind |
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13 56962 | Jul 2013 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/FR2014/051768 | 7/10/2014 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2015/007978 | 1/22/2015 | WO | A |
Number | Name | Date | Kind |
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3442099 | Auville | May 1969 | A |
3884053 | Niederer | May 1975 | A |
4682480 | Schnegg | Jul 1987 | A |
6158255 | Ternon | Dec 2000 | A |
20040152384 | Ommerborn | Aug 2004 | A1 |
Number | Date | Country |
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2308707 | Apr 2011 | EP |
Number | Date | Country | |
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20160153127 A1 | Jun 2016 | US |