JP2011190561A - Method for producing fabric, and fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To certainly prevent a yarn gap of a polytetrafluoroethylene fabric without depending on use of a heat fusible resin fiber, and, in addition, on a method for pasting a film. <P>SOLUTION: The fabric is formed by using a polytetrafluoroethylene yarn, and the fabric is heat-treated at a temperature of not less than 240°C and not more than 400°C. The fabric may be formed by using the polytetrafluoroethylene yarn and an auxiliary yarn constituted of a material different from the polytetrafluoroethylene. A fiber used as a reinforcing yarn can be a heat fusible resin fiber or a non-heat fusible fiber. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a fabric using polytetrafluoroethylene yarn, and the fabric.

  Fabrics made of polytetrafluoroethylene fiber yarns are utilized in various applications by taking advantage of the properties of polytetrafluoroethylene such as heat resistance, mold release, chemical resistance, weather resistance, and low friction characteristics. Fibers obtained by stretching polytetrafluoroethylene fibers can further add toughness, and are used according to applications. More specifically, it is a sheet-like sliding member disposed on a sliding surface of a machine part, and is a sliding member that is used by impregnating a liquid lubricant such as oil. This sliding member is used, for example, in an image fixing device such as a copying machine, a printer, or a facsimile. In addition, for example, heat-resistant release sheet applied to the surface of the heater to prevent adhesion of the sealed member used in the heating part of the impulse sealer, or processing containers and parts by heat-deforming plastic resin with a hot mold In some cases, it is used as a release sheet provided between a plastic material and a thermal mold. Since the polytetrafluoroethylene material has heat resistance and releasability, it can be used for a transport belt for transporting food immediately after heating (a material that is hot and remains adhesive). Furthermore, it is suitably used as a cover material (such as a roof material of a building, a tent material, or a radome cover material) in a place exposed to ultraviolet rays for a long period of time, such as outdoors where weather resistance is required.

  However, the polytetrafluoroethylene fiber has some special characteristics as described above, and therefore has a difficult part to process. For example, polytetrafluoroethylene has a very high melt viscosity and a very low reactivity, so that it is difficult to adhere to other materials. In addition, since the chemical resistance is high, it is difficult to treat the surface and bond it to other materials. In particular, when a fabric is formed using polytetrafluoroethylene yarn, the frictional resistance of the polytetrafluoroethylene yarn is very small, so that it is slippery and yarn slippage (necking) occurs.

  By the way, in general, fibers (heat-melting resin fibers) having a low heat-melting temperature and a low heat-melting viscosity are mixed for the purpose of preventing yarn misalignment of the fabric, and the intersecting points of the circumstances are melted and fixed by melting the heat-melting resin fibers. The method is known.

  In Patent Document 1, a first fiber and a second fiber that does not decrease in strength due to heat at the temperature of the melting point of the first fiber and hardly changes in shape are arranged on both sides of the first fiber. The first and second fibers of the warp and the first fiber of the weft are heated at the intersection point. A fused lattice fabric is described.

  Patent Document 2 discloses a mesh base material using a fiber body composed of a high melting point component or a non-heat-melting component and a heat-fusible yarn body containing at least two components having a difference in melting temperature. The mixing ratio of the fiber body and the heat-fusible thread is 50/50 to 90/10 by weight, and the melting temperature is low at the intersection of the heat-fusible thread. A mesh sheet for building construction is described in which the components are sealed by heat welding the components.

  In addition to the method of using the above-described hot-melt resin fiber as a measure for preventing misalignment, a method of attaching a film to a fabric or impregnating a resin with a fabric is also known.

Japanese Patent Laid-Open No. 7-145532 (Claim 1, FIG. 1, etc.) Japanese Patent Laid-Open No. 10-102348 (Claim 1, FIG. 1, etc.)

  However, the polytetrafluoroethylene material has high releasability and low frictional force, and therefore has low adhesion to other materials. Therefore, neither of the methods disclosed in Patent Documents 1 and 2 was very effective as a measure for preventing yarn misalignment. That is, even when a mixed fabric of polytetrafluoroethylene fiber and the above-mentioned heat-meltable resin fiber is prepared and only the heat-meltable resin fiber is melted and fixed, the polytetrafluoroethylene yarn is still used while the fabric is used. There was a problem of dropping out. Of course, if the use ratio of the heat-meltable resin fiber is increased and the entire fabric is covered with the heat-meltable resin fiber, the dropping of the polytetrafluoroethylene yarn and the yarn displacement are reduced, but the properties of the fabric are the properties of the heat-meltable resin fiber. Thus, the high heat resistance, weather resistance, and chemical resistance of the polytetrafluoroethylene material are diminished.

  On the other hand, a method of attaching a resin film to the fabric can also be selected, but this leads to an increase in manufacturing cost. Usually, the resin film is affixed to one side of the fabric, but attention should be paid to the front and back of the fabric when the fabric is used. If the wrong side is used, the expected function cannot be obtained.

  The present invention has been made to overcome the above-described situation, and does not depend on the use of heat-meltable resin fibers as a measure for preventing yarn displacement, and also depends on the method of attaching the resin film. The purpose is to establish a technique for preventing yarn misalignment of a polytetrafluoroethylene fabric.

The method for producing the fabric of the present invention that has solved the above-mentioned problems is as follows.
A fabric is formed using polytetrafluoroethylene yarn, and the fabric is heat-treated at a temperature of 240 degrees or more and 400 degrees or less. Since the melting point of polytetrafluoroethylene is very high, the idea of thermally modifying a fabric using polytetrafluoroethylene yarn was not based on industrial mass production. However, when the present inventors repeated heat treatment experiments under various temperature conditions on the fabric formed of polytetrafluoroethylene yarn, when the fabric was heated to 240 degrees or more, the shrinkage of the polytetrafluoroethylene yarn began, As a result of the shrinkage, the entire yarns constituting the fabric were firmly bound to each other, and as a result, it was confirmed that the pulling force of the polytetrafluoroethylene yarn was increased. That is, the present invention is a new method different from the conventional method (1) using a heat-meltable resin fiber and (2) a method by sticking a resin film, particularly in a fabric using polytetrafluoroethylene yarn. A suitable yarn slip prevention method has been found.

  In the above manufacturing method, it is of course effective to additionally use a reinforcing yarn made of a material different from polytetrafluoroethylene in addition to the polytetrafluoroethylene yarn.

  In the manufacturing method described above, it is desirable that the reinforcing yarn includes fibers of a heat-meltable resin, and the temperature of the heat treatment is not less than the softening point of the heat-meltable resin and less than the melting point. Conventionally, in the case of using a heat-meltable resin, it was originally intended to use a heat-meltable resin to perform a heat treatment at or above the melting point of the heat-meltable resin. Heat above the softening point of the meltable resin, but not above the melting point. In this method, the deformed hot-melt resin fills a slight gap between the polytetrafluoroethylene yarns, so that it is possible to further improve the yarn displacement prevention force and to produce a fabric having a good appearance.

  In the above manufacturing method, the heat-meltable fiber is preferably a fluororesin fiber.

  In the above production method, the reinforcing yarn may include a non-heat-meltable fiber.

  In the above production method, it is desirable that the polytetrafluoroethylene is expanded porous polytetrafluoroethylene.

  In the above manufacturing method, it is desirable that the temperature of the heat treatment be 360 degrees or more and 400 degrees or less.

  In the above manufacturing method, it is desirable to perform the heat treatment while pressing the fabric in the thickness direction of the fabric.

  In the above manufacturing method, the fabric may be a woven fabric.

The fabric of the present invention that has solved the above problems is
A fabric obtained by heat-treating a fabric formed using polytetrafluoroethylene yarn, wherein a value (mN) obtained by multiplying the yarn pull-out force (N) based on JIS L1062 B method by 1000 (mN) A value obtained by dividing the denier value (d) by the number of drivings per inch of fabric (lines / inch) (hereinafter referred to as “standardized pulling force”. Unit: mN / {d · (lines / inch)}) It is 0.3 or more.

  The fabric of the present invention that can solve the above-mentioned problems is a fabric manufactured by the above fabric or the above method, and has an opening ratio of 10% or less.

  The present invention is a fabric including polytetrafluoroethylene yarn, and the fabric is heat-treated. This fabric is more excellent in preventing yarn displacement than a fabric containing conventional polytetrafluoroethylene yarn, and can provide a tough sliding material, release sheet and protective cover.

It is a graph which shows the pulling-out force of the thread | yarn in Experimental example 1 of this invention. It is a graph which shows the pulling-out force of the thread | yarn in Experimental example 3 of this invention.

  Embodiments of the present invention will be described below. In the present invention, after a polytetrafluoroethylene yarn is processed into a fabric, heat treatment is performed to shrink the yarn, and a fabric in which the polytetrafluoroethylene yarns are firmly adhered to each other by the shrinkage force is provided.

  Hereinafter, (1) polytetrafluoroethylene yarn, (2) fabric, and (3) heat treatment, which are basic components of the method for producing a fabric of the present invention, will be described in detail.

(1) Polytetrafluoroethylene yarn The yarn used in the fabric of the present invention contains polytetrafluoroethylene (PTFE) fiber. As polytetrafluoroethylene fiber, for example, porous polytetrafluoroethylene fiber or non-porous polytetrafluoroethylene fiber is used. From the viewpoint of increasing the strength of the fiber, it is preferable to use a stretched polytetrafluoroethylene fiber.

  For example, porous polytetrafluoroethylene is obtained by mixing and molding PTFE fine powder and a molding aid, removing the molding aid, stretching at a high temperature and a high speed, and further firing if necessary. A fibrous material can be formed by finely tearing the obtained porous polytetrafluoroethylene along the stretching direction or by cutting it into slits.

  The yarn used in the present invention is a yarn containing polytetrafluoroethylene fibers as described above. However, if the fibers are bundled, voids are formed between the fibers, and the shrinkage when the heat treatment is performed is voids. Easy to absorb. This can prevent the texture from shifting in the case of the woven fabric when contracted. Therefore, in the present invention, it is more preferable to use fiber bundle yarns.

  More specifically, the fiber bundle refers to a plurality of polytetrafluoroethylene short fibers (2 or more (preferably 8 or more, more preferably 15 or more)), 100 or less (preferably 80 or less, more preferably 50 or less))) are collected and bundled, and include, for example, a simple bundle of short fibers and a twisted bundle of short fibers.

  In consideration of the balance between the thickness of one fiber and the number of fibers contained in the fiber bundle, 10 to 100 denier (0.9 denier is 1 dtex) stretched polytetrafluoroethylene fiber is bundled, and the fiber bundle 1 The book is preferably 200 denier or more. Furthermore, as an optimum range, it is possible to bundle 10 to 50 denier fibers (porous PTFE fibers) with a fiber bundle of 200 to 1000 deniers, and to balance strength and lubricant retention. Is good.

  In order to maintain a preferable strength, the polytetrafluoroethylene fiber is desirably, for example, 10 denier or more (more preferably 20 denier or more, and further preferably 30 denier or more). When the fabric of the present invention is used as a sliding member of an image fixing device used in a copying machine, a printer, a facsimile machine, etc., if the woven fabric is constituted by yarns made by bundling polytetrafluoroethylene fibers, the woven fabric When the lubricant infiltrated into the polytetrafluoroethylene fibers enters not only between the bundles of polytetrafluoroethylene fibers but also between the polytetrafluoroethylene fibers and the polytetrafluoroethylene fibers, the retention of the lubricant is improved. In order to exhibit such an effect more effectively, it is desirable that the polytetrafluoroethylene fiber is, for example, 100 denier or less (more preferably 80 denier or less, further preferably 70 denier or less).

(2) Fabric The fabric of the present invention is a fabric woven with polytetrafluoroethylene yarn (woven fabric) or a woven fabric (knitted fabric). The weaving and knitting methods of the fabric used in the present invention are not particularly limited, but examples of weaving methods include plain weaving, satin weaving, twill weaving, leash weaving, and imitation weaving. In the present invention, plain weave or satin weave is preferred from the viewpoint of wear resistance and slidability. From the viewpoint of the strength and handleability of the woven fabric, the thickness of the woven fabric is 0.1 to 1 mm, more preferably 0.2 to 0.5 mm. When the fabric of the present invention is used as a sliding member of an image fixing device used in a copying machine, a printer, a facsimile machine or the like, it is desirable to use at least one of warp and weft as twisted yarn.

(3) Heat treatment The fabric in the present invention is heat-treated. That is, the object to be heat-treated is cloth. Therefore, the present invention does not prescribe any heat treatment for the yarn before making it into a cloth state, but prescribes heat treatment after making it into a cloth state. When a fabric woven with polytetrafluoroethylene yarn is subjected to heat treatment, the yarn contracts tightly so that the entire fabric is tightened by shrinkage of the yarn, and resistance to yarn displacement is improved. Also, fraying of the fabric yarn is reduced.

  The temperature of the heat treatment may be a temperature lower than the melting point of polytetrafluoroethylene. Even in that case, the shrinkage of the yarn improves the resistance against the yarn displacement, that is, the resistance against the drawing of the yarn. As a result of various experiments, the temperature of the heat treatment necessary for exhibiting such an effect is 240 ° C. or higher (preferably 250 ° C. or higher, more preferably 260 ° C. or higher).

  The heat treatment temperature for more reliably exhibiting the effect of preventing yarn displacement is 360 ° C. or more, more preferably 370 ° C. or more. In this case, since a part of the yarns are fused by melting the polytetrafluoroethylene yarn, the effect of preventing yarn misalignment is further enhanced.

  On the other hand, if the temperature of the heat treatment is too high, the texture of the woven fabric is lost, or the surface of the woven fabric is wavy or the fibers are cut, so the upper limit of the heat treatment temperature is 400 degrees (preferably 390 degrees, More preferably, 380 degrees).

  Although the specific method of heat-treating the fabric is not particularly limited, for example, a belt-shaped fabric is prepared, and the fabric is sequentially wound using a winding roll while the fabric is in contact with a heating rotating body having a heater inside. Thus, there is a method of continuously heat-treating the fabric. This method has the advantage of high production efficiency and stability. In order to shrink the fabric evenly, it is desirable to bring the fabric into uniform contact with the heating rotator. Alternatively, a method may be adopted in which a plurality of fabrics are wound around a metal cylindrical object and the heat treatment is performed by placing the cloth in a thermostat for a certain period of time.

  By the way, when a strong fabric is produced by heating and shrinking a polytetrafluoroethylene yarn, the fabric is an assembly of yarns, and the yarns have slight variations in thickness and density. For this reason, when the fabric is left untreated in the heat treatment environment and processed, the shrinkage differs due to slight variations in the thickness and density of the yarn, and the fabric is wrinkled and wavy. Such deformation may cause quality problems, such as when the fabric is used as a sliding member, for example, the contact area with the sliding counterpart member varies, and when it is used as a heat-resistant release sheet, the amount of heat conduction varies. appear.

  Therefore, in the case of heat treatment, some physical regulation (pressing) is required so that the yarn shrinks uniformly. It is desirable to heat-treat while pressing the fabric in the thickness direction of the fabric. As a specific method, there are a hot press method in which a hot mold is used, and a hot roll press method in which a hot roll is passed.

  As described above, by heat-treating a fabric composed of polytetrafluoroethylene yarn, it is possible to obtain a fabric that is less likely to cause yarn slippage and is less likely to fray even when used for a long time.

  The fabric of the present invention as a basic structure can be further provided with the characteristics described below to obtain a fabric having more excellent characteristics.

(4) Reinforcement yarn The fabric of the present invention may be composed only of polytetrafluoroethylene yarn, but a reinforcement yarn composed of a material different from polytetrafluoroethylene (a material different from polytetrafluoroethylene). (It is not particularly limited except that). Due to the action of the reinforcing yarn, the effect of preventing the yarn slippage of the fabric containing the polytetrafluoroethylene yarn is more effective. Hereinafter, the case where the material of the reinforcing yarn is (1) a heat-meltable resin fiber and (2) a non-heat-meltable fiber will be described in detail.

(4-1) Hot-melt resin fiber The fabric of the present invention is mixed with a yarn made of hot-melt resin fiber, and heat-treated at a temperature equal to or lower than the heat melting temperature of the resin and equal to or higher than the softening temperature. As a result, the fiber made of the heat-meltable resin is deformed to fill a slight gap in the polytetrafluoroethylene yarn, so that the effect of preventing yarn displacement is improved and the heat treatment temperature is not too high so that a fabric having a good appearance can be obtained. It became.

  As described above, conventionally, it has been customary to use a method in which yarns having different melting points are mixed into a fabric, and the yarns are melted by heating to a temperature higher than the melting point of the lower melting point to fix the yarns. . However, the present invention is completely different from conventional yarn misalignment prevention measures in that even if a heat-meltable resin is mixed into the fabric, it does not heat above the melting point.

  When a fluororesin is used as the heat-meltable resin, yarn slippage prevention can be realized without significantly impairing the chemical resistance and heat resistance of the polytetrafluoroethylene yarn. Examples of the meltable fluororesin include tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) fiber, tetrafluoroethylene / hexafluoropyruvylene copolymer (FEP) fiber, tetrafluoroethylene / ethylene copolymer (ETFE). ) Fiber, polychlorotrifluoroethylene (PCTFE) fiber, chlorotrifluoroethylene / ethylene copolymer (ECTFE) fiber, polyvinylidene fluoride (PVDF) fiber, polyvinyl fluoride (PVF) fiber, and the like.

  When heat-treating a fabric in which polytetrafluoroethylene yarn is mixed with a heat-meltable resin fiber, temperature setting is important. For example, when FEP is used as the heat-meltable resin, the heat treatment is performed at a temperature at which the polytetrafluoroethylene yarn contracts at 240 ° C. or higher, and at a temperature higher than the softening point of the FEP, It is preferable that it is processed by a method such as hot pressing at less than 270 degrees). In particular, immediately before the melting point, for example, less than 260 degrees (preferably less than 265 degrees) is desirable. By heat-treating below the melting point of this resin and above the softening point temperature, the heat-meltable resin melts and does not adhere to the press mold, etc. Therefore, it is possible to improve the yarn displacement prevention force and to make the fabric have a good appearance.

(4-2) Non-heat-meltable fiber Polytetrafluoroethylene yarn has low creep resistance. For example, when a fabric made of polytetrafluoroethylene yarn is used for a conveyor belt, if the belt is stretched with high tension by two rotating belt drive units, the belt stretches, causing a slip phenomenon between the belt and the drive unit. The problem that things cannot be carried out occurs.

  In order to solve such a problem, a fabric in which polytetrafluoroethylene yarn and non-heat-meltable fiber are combined can be used.

  Non-heat-meltable fibers include natural fibers such as cotton, hemp, and silk. This may be used as it is, or a fabric formed using a flame-retardant treatment that does not burn at 240 degrees or more. Other non-heat-meltable fibers include chemical fibers such as aramid fibers, and fibers composed of inorganic substances such as glass fibers, carbon fibers, and metal fibers.

  When the yarn of non-heat melting property is woven into the fabric of the present invention, the above-described creep phenomenon can be alleviated. Since non-heat meltability cannot be bonded and fixed by the method of heat melting, conventionally, adhesives, fixing sheets, etc. have been used as measures for preventing yarn misalignment of fabrics made of polytetrafluoroethylene yarn and non-heat melt fiber yarn. Was generally used. However, these methods have a problem of cost increase due to an increase in material cost and the number of processes, and a problem that high releasability of polytetrafluoroethylene yarn is reduced by adding another material. If the method of keeping the yarn strong by utilizing the heat shrinkage of the present invention is adopted, it is possible to form a fabric that does not shift by only the polytetrafluoroethylene yarn and the non-heat-meltable fiber, and the polytetrafluoroethylene is low in cost. It is possible to maintain a high releasability equivalent to that of a fabric composed only of yarn.

  When a combination of polytetrafluoroethylene yarn and non-heat-meltable fiber yarn is used, the non-heat-meltable fiber may be mixed within a range of 25% or less in terms of the basis weight ratio with respect to the polytetrafluoroethylene fiber.

  The fabric of the present invention is a fabric obtained by heat-treating a fabric formed using polytetrafluoroethylene yarn, and is a value obtained by multiplying the yarn pull-out force (N) based on JIS L1062 B method by 1000 ( mN) divided by the yarn denier value (d) and the number of drivings per inch of fabric (lines / inch) (standardized pulling force: mN / {(d · (lines / inch)}) With such a configuration, a fabric with little yarn displacement can be provided.

  The opening ratio of the fabric of the present invention (the ratio of the area of the void in the entire observation region when the area of the void surrounded by the warp and the weft is obtained by performing enlarged observation of the fabric) should be 10% or less. As a result, the thread pulling force is improved.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.

(Experimental example 1)
1. Preparation of sample As a polytetrafluoroethylene yarn used in a test for confirming the effect of the present invention, Japan Gore-Tex Co., Ltd. (product number: Y003TO) was used. This uses a fiber produced by finely tearing a stretched porous polytetrafluoroethylene (stretched porous PTFE fiber) in the stretching direction. The average thickness of the torn expanded porous PTFE fiber is 20 denier. On average, 15 such stretched porous PTFE fibers are bundled to form a 300 denier yarn. In Experimental Example 1, a woven fabric having a thickness of 0.2 to 0.3 mm was produced by making this fiber bundle into a plain weave.

  The woven fabric formed of the above-mentioned torn expanded porous PTFE fibers was uniformly contacted with a rotary heating body capable of adjusting the surface temperature, and subjected to continuous heat treatment at a treatment speed of 0.1 m / min. Sample 1 (no heat treatment), sample 2 subjected to heat treatment at 200 ° C. (degrees), sample 3 subjected to heat treatment at 230 ° C., sample 4 subjected to heat treatment at 240 ° C., heat treatment at 260 ° C. while changing the heat treatment temperature Sample 5 subjected to heat treatment, Sample 6 subjected to heat treatment at 330 ° C., Sample 7 subjected to heat treatment at 360 ° C., Sample 8 subjected to heat treatment at 380 ° C. were produced.

2. Measurement of Pull-out Force With respect to Samples 1 to 8 described above, the pull-out force in the weft direction (JIS L1062 (Method B of fabric wetting test)) was measured. The results are shown in Table 1 (the pulling force is described as “strength”). In addition, FIG. 1 shows a graph of the results in Table 1.

  As can be seen from Table 1 and FIG. 1, the pulling force was less than 11 (N) for Samples 1 to 3 where the heat treatment temperature for the woven fabric formed from the stretched porous PTFE yarn was less than 240 ° C. On the other hand, the samples 4 to 8 produced by applying heat treatment at 240 ° C. or higher have a pulling force of 12 (N) or more, and in particular, the samples 7 and 8 subjected to heat treatment at 360 ° C. or higher have a pulling force. 14 (N) or more. From the above results, it is possible to produce a fabric with a large pulling force and a small yarn displacement by forming a fabric using polytetrafluoroethylene yarn and heat-treating the fabric at a temperature of 240 ° C. or higher and 400 ° C. or lower. Became clear.

(Experimental example 2)
Sample 9 was produced by heat treating a woven fabric of stretched porous PTFE yarn similar to Experimental Example 1 using every other weft yarn of PFA (heat-melting resin) at 260 degrees. When the same pull-out strength was measured for Sample 9, a pull-out force of 13.8 (N) was obtained. From this experiment, it was confirmed that when a hot-melt resin fiber is used as the reinforcing yarn, a high pulling force can be obtained even at a relatively low temperature heat treatment.

(Experimental example 3)
Because we made eight types of woven fabrics (Sample 11 to Sample 18) with different weight (denier number) or heat treatment temperature of the stretched porous PTFE fiber, and measured the opening ratio of the woven fabric and the pulling force of the yarn. Details are shown below.

  As Sample 11, the same woven fabric as Sample 1 of Experimental Example 1 was produced. Moreover, the same woven fabric as the sample 7 of Experimental example 1 was produced as the sample 15.

  As Sample 12, a woven fabric having a thickness of 0.3 to 0.4 mm was produced by making a polytetrafluoroethylene yarn made by Japan Gore-Tex Co., Ltd. (product number: Y006TO) into a plain weave. This yarn uses a fiber produced by finely tearing a stretched porous PTFE fiber in the stretching direction. The fineness of the torn expanded porous PTFE fiber is an average of 40 denier. On average, 15 such stretched porous PTFE fibers are bundled to form a 600 denier yarn.

  As sample 13, a woven fabric having a thickness of 0.1 to 0.2 mm was prepared by making a polytetrafluoroethylene yarn made by Japan Gore-Tex Co., Ltd. (product number: Y001) into a plain weave. The yarn used for Sample 13 is not a bundle of stretched porous PTFE fibers that are torn and bundled in the stretching direction like the yarn of Sample 12, but a 100-denier yarn that has been produced by stretching is used without being torn. is there.

  As sample 14, a woven fabric having a thickness of 0.2 to 0.3 mm was prepared by making a polytetrafluoroethylene yarn made by Japan Gore-Tex Co., Ltd. (product number: Y004) into a plain weave. The yarn used for sample 14 is not a bundle of stretched porous PTFE fibers that are torn and bundled in the stretching direction like the yarn of sample 12, but a 300-denier yarn that has been produced by stretching and is used as it is without being torn. is there. However, it was produced with a gap between yarns when making a woven fabric.

  A plurality of samples 12 to 14 were prepared, and another sample was prepared using a part of them. Sample 16 was produced by bringing Sample 12 into uniform contact with a rotary heating body capable of adjusting the surface temperature and subjecting it to a continuous heat treatment at 360 ° C. at a treatment speed of 0.1 m / min. Samples 13 to 17 and samples 14 to 18 were manufactured under the same heat treatment conditions.

  The above samples 11 to 18 were each measured for the pulling force in both directions of weft and warp (Method B of JIS L1062 (woven fabric texture test method)). Then, by dividing the value (mN) obtained by multiplying the measured yarn pull-out force (N) by 1000 (mN) by the denier value (d) of the yarn to be pulled out and the number of driving (inch / inch) per inch of woven fabric, A value (standardized pulling force: mN (milli N) / {d · (lines / inch)}) excluding the influence of yarn thickness and density was obtained.

  Similarly, the samples 11 to 18 were enlarged and observed, and the area of the void surrounded by the warp and the weft was measured. The ratio of the voids in the entire observation region was calculated, and this was used as the “opening ratio” of the fabric. The results are shown in Table 2. In addition, FIG. 2 shows a graph of the standardized pulling force results for the samples in Table 2. In addition, about the thing whose aperture ratio is less than 1%, it described as "<1%" uniformly.

As can be seen from Table 2 and FIG. 2, for samples 11 to 14 which are conventional woven fabrics, the standardized pulling force is 0.3 mN / {even if the denier value and the number of driving of the polytetrafluoroethylene yarn are increased. d · (lines / inch)}, but samples 15 to 17 according to the present invention in which heat treatment was applied to the woven fabric were standardized for the first time as a woven fabric using polytetrafluoroethylene yarn. The pulling force was 0.3 mN / {d · (lines / inch)} or more. However, for sample 18 with an extremely high aperture ratio of 40%, the pull-out force was improved by heat treatment, but weft: 0.21 mN / {d · (lines / inch)}, warp: 0.22 mN / {D · (book / inch)}.

Claims (11)

  A method for producing a fabric, comprising forming a fabric using polytetrafluoroethylene yarn and heat-treating the fabric at a temperature of 240 ° C or higher and 400 ° C or lower.   The method for producing a fabric according to claim 1, wherein the fabric is formed by using the polytetrafluoroethylene yarn and a reinforcing yarn made of a material different from polytetrafluoroethylene.   The method for producing a fabric according to claim 2, wherein the reinforcing yarn includes fibers of a heat-meltable resin, and a temperature of the heat treatment is set to be equal to or higher than a softening point of the heat-meltable resin and lower than a melting point.   The method for producing a fabric according to claim 3, wherein the heat-meltable resin is a fluororesin.   The method for producing a fabric according to claim 2, wherein the reinforcing yarn contains non-heat-meltable fibers.   The method for producing a fabric according to any one of claims 1 to 5, wherein the polytetrafluoroethylene is expanded porous polytetrafluoroethylene.   The method for producing a fabric according to any one of claims 1 to 6, wherein a temperature of the heat treatment is set to 360 degrees or more and 400 degrees or less.   The method for manufacturing a fabric according to any one of claims 1 to 7, wherein the heat treatment is performed while pressing the fabric in the thickness direction of the fabric.   The method for producing a fabric according to any one of claims 1 to 8, wherein the fabric is a woven fabric.   A fabric obtained by heat-treating a fabric formed using polytetrafluoroethylene yarn, wherein a value (mN) obtained by multiplying the yarn pull-out force (N) based on JIS L1062 B method by 1000 (mN) A fabric having a value (mN / {d · (lines / inch)}) divided by the denier value (d) and the number of drivings per inch (lines / inch) is 0.3 or more. The fabric manufactured by the method according to any one of claims 1 to 9, or the fabric according to claim 10, wherein the opening ratio is 10% or less.