JP2008280636A - Woven or knitted fabric for forming and filter using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a woven or a knitted fabric for forming scarcely causing yarn slippage, having excellent dimensional stability, durability etc., and suitably usable for formed products and to provide a filter using the woven or the knitted fabric for forming. <P>SOLUTION: The woven or the knitted fabric for forming has 8-20 N/mm initial yarn slippage stress in at least one of the warp and the weft directions. The woven or the knitted fabric for forming is preferably obtained by using yarns composed of core-sheath type conjugated fibers in which a polyester A consisting essentially of an alkylene terephthalate unit and having ≥220°C melting point is arranged in a core part and a polyester B having a lower melting point than that of the polyester A by ≥30°C is arranged in a sheath part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a forming woven or knitted fabric having a high initial misalignment stress and suitable for a molded product, and a filter using the forming woven or knitted fabric.

  Many composite fibers have been proposed so far in which a low melting point polymer is disposed in a sheath and heat-treated to melt the sheath.

For example, Patent Document 1 uses a polyester-based heat-adhesive conjugate fiber in which polyethylene terephthalate (PET) is used as a core component and a PET copolymer obtained by copolymerizing a terephthalic acid component and an isophthalic acid component is used as a sheath component. A woven fabric is disclosed. Patent Document 2 discloses a woven fabric in which a high-melting monofilament and a low-melting monofilament are combined and heat-sealed using a fusion yarn in which the surface of the low-melting monofilament is exposed.
Japanese Patent No. 3459952 JP 2004-149964 A

  All of the above fabrics can be used as a base fabric for molded products such as filters and interior products, but there are some problems.

  That is, in the fiber described in Patent Document 1, since the PET copolymer is amorphous and does not exhibit a clear crystal melting point, softening starts at a temperature above the glass transition point. Therefore, when the woven fabric is heat-treated for the purpose of melting the sheath component, there is a problem that the fiber contracts and misalignment occurs in the entire product. For example, when the obtained product is used as a filter in a high temperature atmosphere, misalignment occurs and sometimes even deformation occurs as the adhesive strength decreases.

  Further, the fusion yarn described in Patent Document 2 is intended to effectively prevent the collapse of the fabric without using expensive fibers such as core-sheath fibers. However, when producing a molded product using this fused yarn, there is a problem that misalignment occurs as in the above-described invention. In addition, in order to make the resulting fabric more than a certain level of dimensional stability and durability, the thickness and weight of the fabric must be increased. For example, beverage filters such as tea packs, coffee filters, and tea strainers were produced. In this case, a problem arises that the thickness is excessively increased and is not suitable for practical use.

  The present invention solves the above-described problems, is less likely to cause misalignment, is excellent in dimensional stability and durability, and can be suitably used for a molded product. The object of the present invention is to provide a filter using a woven or knitted fabric.

  As a result of investigations to solve the above problems, the present inventors have reached the present invention.

That is, the gist of the present invention is as follows.
(1) A forming knitted or knitted fabric characterized by having an initial misalignment stress of 8.0 to 20.0 N / mm at least on one side in the weft direction.
(2) A yarn composed of a core-sheath type composite fiber in which a polyester A mainly composed of an alkylene terephthalate unit and having a melting point of 220 ° C. or higher is disposed in the core, and a polyester B having a melting point of 30 ° C. or lower than that of the polyester A The woven or knitted fabric for molding as described in (1) above, wherein
(3) Polyester B is a copolymerized polyester containing a terephthalic acid component and an ethylene glycol component, and copolymerized with at least one component of a 1,4-butanediol component, an aliphatic lactone component and an adipic acid component (2 ) Woven and knitted fabric for molding described.
(4) A filter using the forming woven or knitted fabric according to any one of (1) to (3).

  Since the woven or knitted fabric for molding of the present invention has a predetermined initial misalignment stress, misalignment at the texture point is unlikely to occur. The woven or knitted fabric for molding of the present invention has excellent dimensional stability and durability.

  Therefore, the woven or knitted fabric for molding of the present invention is suitable as a woven or knitted fabric for molding, and among them, is most suitable for a filter.

  Hereinafter, the present invention will be described in detail.

  The woven or knitted fabric for molding of the present invention can be applied to various molded products. Molded products include, for example, beverage filters such as tea packs, coffee filters, tea strainers, household appliance filters attached to vacuum cleaners, air conditioners, air cleaners, clothing products such as clothes and interlining, cushions, curtains, etc. Examples include interior products, building materials, civil engineering materials, and industrial materials such as substrates. However, the use of the knitted and knitted fabric for molding of the present invention is not limited to these and can be widely applied to molded products in general. is there.

  In the woven or knitted fabric for molding of the present invention, misalignment at the structure point is unlikely to occur. Specifically, the initial misalignment stress measured by applying JIS L1096 8.21.3 (pin hooking method) is 8.0 to 20.0 N / mm at least on one side in the weft direction. It is necessary and it is preferable to satisfy the range in both directions. Here, the initial misalignment stress is calculated by the following formula (1) after inserting a metal pin into a sample and attaching the pin to a fabric tensile tester, obtaining an elongation (ON) at a resistance of 20.0 N. Is. The initial misalignment stress is measured in the weft / knitted direction.

  When the initial misalignment stress is less than 8.0 N / mm, it cannot be used as a molded product. For example, when a woven or knitted fabric is applied to the above-mentioned filter for home appliances, generally, the filter is regularly cleaned. However, when the surface of the knitted or knitted fabric is rubbed with a brush or the like at this time, misalignment occurs at the tissue point. On the other hand, if it exceeds 20.0 N / mm, the flexibility of the molded product is reduced and the application is limited.

  In the present invention, the initial misalignment stress can be set within a predetermined range by increasing the adhesive strength at the texture point of the woven or knitted fabric. The texture point refers to a portion where the yarns intersect in the woven or knitted fabric, a portion where the warp and weft intersect in the woven fabric, and a portion where the loop intersects in the knitted fabric. In such a case, for example, the adhesive strength at the texture point can be increased by heat-treating a woven or knitted fabric using a yarn composed of a low melting point synthetic fiber. The heat treatment temperature at this time is preferably such that the synthetic fiber can be melted, whereby the fibers can be fused to increase the adhesive strength at the tissue point.

  Specifically, any polymer can be used as the polymer constituting the synthetic fiber as long as the fibers can be fused together, but polyester is preferable in consideration of durability and production cost of the woven or knitted fabric. Can be adopted. In addition, the polymer to be used may be independent, but the molten polymer is generally rigid, and there is a tendency that the fusion between fibers tends to come off due to repeated bending. Therefore, it is preferable to use not only a polymer that easily contributes to fusion but also a polymer that hardly contributes to fusion. In this case, the arrangement of each polymer in the fiber is not particularly limited. Preferably, a polymer that easily contributes to fusion is arranged in the outer portion of the fiber cross section as much as possible.

  Considering the above points, as the synthetic fiber that can be used in the present invention, a core-sheath type composite fiber in which a high melting point polyester (polyester A) is arranged in the core and a low melting point polyester (polyester B) is arranged in the sheath is adopted. It is preferable to do.

  Here, as the polyester forming the polyester A, any polyester having a high melting point that does not substantially contribute to fusion can be used. For example, polyesters mainly composed of polyalkylene terephthalate such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polytrimethylene terephthalate (PTT) can be used, and these can be used alone, mixed or copolymerized. Can do.

  In addition, polyester A has, as long as the effects of the present invention are not impaired, as a copolymerization component, isophthalic acid, 5-sodium sulfoisophthalic acid, phthalic anhydride, naphthalene carboxylic acid, trimellitic acid, pyromellitic acid Acid components such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, 4-hydroxybenzoic acid, ε-caprolactone, phosphoric acid, glycerin, diethylene glycol, 1,4-butanediol, trimethylpropane, 1,4-cyclohexane Dimethanol, neopentyl glycol, pentaerythritol, ethylene oxide adduct of 2,2-bis {4- (β-hydroxy) phenyl} propane, and the like may be copolymerized. Furthermore, an additive such as an antioxidant, a matting agent, a colorant, a lubricant, and a crystal nucleating agent may be contained in the polyester A as long as the effects of the present invention are not impaired.

  And as melting | fusing point of polyester A, 220 degreeC or more is preferable and 220-280 degreeC is more preferable. When the melting point of polyester A is less than 220 ° C., the strength retention after dry heat treatment of the yarn composed of the core-sheath type composite fiber tends to be low, and it may be difficult to spin stably. Yes, not preferred. In addition, after obtaining a woven or knitted fabric, use at a high temperature is not preferable because it tends to decrease the dimensional stability.

  On the other hand, as the polyester forming the polyester B, any polyester having a low melting point that can substantially contribute to fusion can be used. For example, a copolyester containing a terephthalic acid component and an ethylene glycol component and copolymerizing at least one of a 1,4-butanediol component, an aliphatic lactone component and an adipic acid component can be mentioned. In particular, a copolyester comprising a terephthalic acid component, an aliphatic lactone component, an ethylene glycol component, and a 1,4-butanediol component has a relatively high crystallization speed, which is preferable from the viewpoint of cooling during spinning or after heat bonding. . The aliphatic lactone component is preferably a lactone having 4 to 11 carbon atoms, and a particularly preferred lactone is ε-caprolactone (ε-CL).

  Further, an additive such as an antioxidant, a matting agent, a colorant, a lubricant, a crystal nucleating agent, etc. may be contained in the polyester B as long as the effect is not impaired.

  Furthermore, the polyester B preferably has crystallinity. Thereby, the fiber can be sufficiently heat-treated in the fiber production process, and the strength retention rate and shrinkage rate after the dry heat treatment of the yarn can be set to a desired range.

  The melting point of polyester B is preferably 30 ° C. or lower than polyester A. If the difference in melting point from the polyester A is less than 30 ° C., when the polyester B is melted, the heat treatment temperature may have to be set to a high temperature, resulting in deterioration of the core-sheath composite fiber. This is not preferable. The specific melting point of polyester B is preferably 130 ° C to 200 ° C, the glass transition point is preferably 20 to 80 ° C, and the crystal start temperature is preferably 90 to 130 ° C.

  Moreover, as mass ratio (core: sheath) of the core part and sheath part in the said core-sheath-type composite fiber, 40: 60-80: 20 is preferable. Since the ratio of the core part greatly affects the durability of the finally obtained woven or knitted fabric, the above range is preferable, and 50:50 to 80:20 is particularly preferable. If the core ratio is less than 40%, the strength retention after dry heat treatment of the yarn tends to be low. On the other hand, if it exceeds 80%, the absolute amount of polyester B as a melting component is insufficient. There is a tendency that the fibers cannot be sufficiently bonded at the structure point of the knitted or knitted fabric, which is not preferable.

  And although it does not specifically limit as a single yarn fineness of the said core-sheath-type composite fiber, 1.1-56.0 dtex is preferable.

  Further, the shape of the core-sheath type composite fiber may be either a long or short fiber, and the cross-sectional shape is not particularly limited. It may have a rectangular cross-sectional shape or an irregular cross-sectional shape in which a part of the outermost periphery of the cross-section forms a protrusion.

  In the present invention, the core-sheath type conjugate fiber can be preferably used as described above. However, as a specific use mode, the core-sheath type conjugate fiber may be used directly as a monofilament yarn, and spun yarn or multifilament. It may be used after a plurality of fibers are bundled like a yarn. Further, the shape of the yarn is not particularly limited, and for example, in addition to forms such as a flat yarn, a twisted yarn, a mixed yarn, and a false twisted yarn, a yarn in which long and short fibers are combined can be employed. .

  Moreover, as a physical property of the said thread | yarn, 60.0% or more is preferable as a strength retention after a dry heat processing, and 70.0% or more is more preferable. If the strength retention after dry heat treatment is less than 60.0%, the strength of the forming knitted or knitted fabric is inevitably inferior, and the durability of the woven or knitted fabric is also lowered. For example, when it is applied to a beverage filter, it causes tearing, tearing, rupture, etc., and when it is applied to a home appliance filter, it tends to be ruptured, broken, frayed, etc. during repeated use.

  Here, the dry heat treatment means a dry heat treatment at a temperature higher by 10 ° C. than the melting point of the polyester B for 15 minutes with no load. Further, the strength retention after dry heat treatment means that after measuring the strength of the yarn before and after the dry heat treatment at a holding interval of 25 cm using a constant speed extension type tester in accordance with JIS L1013 8.5.1. And is calculated by the following equation (2).

  Furthermore, in the above yarn, the shrinkage rate is preferably 20.0% or less, and more preferably 15.0% or less. If the shrinkage rate exceeds 20.0%, the dimensional stability of the molded product composed of the woven or knitted fabric for molding tends to decrease, and the fiber diameter increases due to heat treatment to obtain a molded product such as a thin filter. It tends to be difficult and is not preferable.

  Here, the shrinkage rate is obtained by measuring the yarn length before and after the dry heat treatment described above and calculating the following equation (3). The yarn length is measured with a load of 0.049 cN / dtex applied.

  In the woven or knitted fabric for molding of the present invention, the above-mentioned yarns can be preferably used as described above. However, fibers other than the core-sheath type composite fiber are included in the above-mentioned yarns as long as the effects of the present invention are not impaired. May be. Here, examples of the fibers other than the core-sheath type composite fiber include polyester, nylon, acrylic, polyurethane, cotton, wool, rayon, acetate, and the like, and include means such as mixed fiber, entanglement, twisting, and drawing. Can be included. It should be pointed out that fibers other than the core-sheath type composite fiber may be included in the forming woven or knitted fabric, for example, by adhering them to the space between the yarns or the surface of the forming knitted or knitted fabric instead of the yarn. Absent.

  Next, a method for producing the molding knitted or knitted fabric of the present invention will be described.

  In the woven or knitted fabric for molding of the present invention, fibers and yarns having any composition and configuration as long as the initial misalignment stress satisfies a predetermined range at least in one of the weft and warp directions and is suitable for a molded product. May be used, and the structure of the woven or knitted fabric may be in any form. However, when it is desired to apply to a wider range of products for molding or to improve various physical properties of the woven or knitted fabric, it is preferable to obtain the woven or knitted fabric using the above-mentioned yarn. It is as follows.

  The core-sheath type composite fiber preferably used in the present invention can be generally produced using a composite spinning apparatus. Specifically, it can be obtained by melt spinning at a take-up speed of 1000 to 4500 m / min and then drawing. In this case, the stretching ratio is preferably 1.5 to 2.0 times, and the heat treatment temperature during stretching is preferably 130 to 170 ° C.

  The take-up speed is preferably 1000 m / min or more from the viewpoint of fiber production efficiency, and is preferably 4500 m / min or less from the viewpoint of suppressing yarn breakage. Regarding drawing, the spun fiber can be wound once and then supplied to a drawing machine, or can be drawn directly after drawing through a drawing roller following spinning.

  After obtaining the core-sheath type composite fiber, a yarn is produced using this fiber. The shape of the yarn may be arbitrary as described above, and known techniques are applied mutatis mutandis as the apparatus and manufacturing conditions. In addition, when producing a flat yarn made of long fibers as a yarn, it is common to produce a yarn at the same time as producing the fiber, such as a twisted yarn, a mixed yarn, a false twisted yarn, etc. Is generally obtained by performing predetermined processing on a flat yarn.

  After the yarn is obtained, a living machine is produced using this yarn. Specifically, when the raw machine is a woven fabric, a loom is used, and when it is a knitted fabric, a knitting machine is used. In this case, you may use together yarns other than the said yarn according to the objective.

  After obtaining a raw machine, it can heat-process at the temperature more than melting | fusing point of the polyester B distribute | arranged to the sheath part of a core-sheath-type composite fiber, and can obtain the knitted fabric for shaping | molding of this invention. The purpose of this heat treatment is to fuse the fibers at the texture point of the woven or knitted fabric to increase the adhesive strength at the texture point, thereby bringing the initial misalignment stress within a predetermined range.

  The forming woven or knitted fabric of the present invention can be obtained by the above method, but the production method is not limited to this and can be obtained by various methods.

  As described above, the woven or knitted fabric for molding of the present invention can be widely applied to all molded products, but is suitable for a filter because it has a predetermined initial misalignment stress. Specific examples of the filter are as described above.

Next, the present invention will be described specifically by way of examples. Various physical property values were measured as follows.
1. Melting | fusing point It measured with the temperature increase rate of 20 degree-C / min using DSC-2 type | mold (differential scanning calorimeter) by Perkin-Elmer.
2. Intrinsic Viscosity Measurement was performed at a concentration of 0.5 g / dl and a temperature of 20 ° C. using a mixture of equal mass of phenol and ethane tetrachloride as a solvent.

Example 1
As polyester A, a PET having a melting point of 256 ° C. and an intrinsic viscosity of 0.64 was used, and as polyester B, a copolymerized polyester obtained by copolymerizing 1,4-butanediol with 50 mol% of PET (intrinsic viscosity: 0.78, melting point). 181 ° C., glass transition point: 48 ° C.). The polyester A is placed in the core and the polyester B is placed in the sheath, and the core-sheath mass ratio (core: sheath) is 50:50, so that the spinning temperature is 280 ° C. and the spinning speed from a normal composite spinning device. An undrawn yarn was obtained by melt spinning at 3000 m / min.

  The obtained undrawn yarn was once wound up and drawn under the conditions of a draw ratio of 1.85 times and a heat treatment temperature of 150 ° C. to obtain a 28 dtex monofilament yarn made of a core-sheath composite fiber.

  The obtained monofilament yarn is applied to the warp and the raw machine density is 97 / 2.54 cm, and the weft density is 95 / 2.54 cm. Weaved. Subsequently, the raw machine was sequentially scoured, preset, dyed and dried. Thereafter, final setting was performed at 190 ° C. for the purpose of heat setting of the fabric and fusion between the fibers. As described above, a woven or knitted fabric for molding of the present invention was obtained.

(Example 2)
A monofilament yarn was obtained in the same manner as in Example 1 except that the core-sheath mass ratio (core: sheath) was changed to 80:20. Thereafter, a plain woven fabric was obtained in the same manner as in Example 1 using the obtained monofilament yarn.

(Example 3)
A 33 dtex monofilament yarn made of PET was used as the warp yarn, and the monofilament yarn used in Example 1 was applied to the weft yarn. Thereafter, the obtained raw machine was processed in the same manner as in Example 1 to obtain a woven or knitted fabric for molding of the present invention. The initial misalignment stress in this woven or knitted fabric was 8.2 N / mm in the warp direction and 8.0 N / mm in the weft direction.

(Reference Example 1)
A monofilament yarn was obtained in the same manner as in Example 1 except that the draw ratio at the time of drawing was changed to 1.7 times and the heat treatment temperature was changed to 120 ° C. Then, the obtained monofilament yarn was used in the same manner as in Example 1. A woven or knitted fabric for molding according to the present invention was obtained.

(Reference Example 2)
A monofilament yarn was obtained in the same manner as in Example 1 except that the core-sheath mass ratio (core: sheath) was changed to 20:80. Thereafter, a plain woven fabric was obtained in the same manner as in Example 1 using the obtained monofilament yarn.

(Comparative Example 1)
Example 1 except that PBT (intrinsic viscosity: 0.85, melting point: 228 ° C., glass transition point: 25 ° C.) obtained by copolymerizing terephthalic acid and 1,4-butanediol is used as polyester B. Similarly, a monofilament yarn was obtained. Thereafter, a woven or knitted fabric was obtained in the same manner as in Example 1 using the obtained monofilament yarn.

(Comparative Example 2)
A monofilament yarn was obtained in the same manner as in Example 1 except that the core-sheath mass ratio (core: sheath) was changed to 90:10. Thereafter, a woven or knitted fabric was obtained in the same manner as in Example 1 using the obtained monofilament yarn.

  The results are summarized in Table 1 below.

  As is clear from Table 1, the knitted and knitted fabrics according to Examples 1 and 2 satisfy the predetermined range of the initial misalignment stress, and were proved to be excellent in durability. Further, since the shrinkage rate of the yarn was low, it was proved that the woven or knitted fabric was excellent in dimensional stability, and it was proved that it was suitable for a molded product such as a filter.

  Note that the knitted or knitted fabric according to Example 3 also had excellent initial durability because the initial misalignment stress satisfied a predetermined range, similar to the woven or knitted fabric according to Examples 1 and 2.

  On the other hand, in Reference Example 1, since the draw ratio and heat treatment conditions were not suitable when producing the yarn, the shrinkage rate of the yarn was high, and as a result, the dimensional stability of the woven or knitted fabric was inferior. In Reference Example 2, since the mass ratio of the core portion in the sheath type composite fiber was low, the strength retention after the dry heat treatment of the yarn was low, and as a result, the durability of the woven or knitted fabric was inferior.

On the other hand, in the woven or knitted fabric according to Comparative Example 1, the melting point of the polyester B in the core-sheath composite fiber was high, and the sheath portion of the fiber could not be sufficiently melted. I couldn't make it. Moreover, in the woven or knitted fabric according to Comparative Example 2, since the mass ratio of the sheath portion in the core-sheath composite fiber is low, the fibers cannot be sufficiently bonded to each other, and the initial misalignment stress of the woven or knitted fabric is set to a predetermined value. I could not.

Claims (4)

  A forming knitted or knitted fabric characterized by having an initial misalignment stress of 8.0 to 20.0 N / mm on at least one side in the weft direction.   Using a yarn composed of a core-sheath type composite fiber in which a polyester A mainly composed of an alkylene terephthalate unit and having a melting point of 220 ° C. or higher is disposed in the core, and a polyester B having a melting point of 30 ° C. lower than that of the polyester A is disposed in the sheath The woven or knitted fabric for molding according to claim 1, wherein   The molding according to claim 2, wherein the polyester B is a copolymerized polyester containing a terephthalic acid component and an ethylene glycol component and copolymerizing at least one component of a 1,4-butanediol component, an aliphatic lactone component and an adipic acid component. Woven knitting. A filter using the molding knitted or knitted fabric according to any one of claims 1 to 3.