Acrylate nonwoven fabric

Abstract

To provide an acrylate nonwoven fabric having both hygroscopic property and elasticity.SOLUTION: An acrylate nonwoven fabric as a needle punched nonwoven fabric containing a mixture of an acrylate fiber having 1 to 10 mmol / g of a carboxyl group and a crimped polyester fiber, has an elongation recovery rate of 65 to 100%, a degree of elongation of 15 to 80%, and a thickness of 1.0 to 10 mm.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an acrylate-based fibrous nonwoven fabric. [Background technology]

[0002] Traditionally, textile materials used for clothing and industrial materials have been natural fibers such as cotton, linen, and wool. In recent years, however, synthetic fibers such as polyester fiber, acrylic fiber, and nylon have become mainstream due to their superior chemical resistance, washing durability, and productivity.

[0003] Clothing is required to be hygroscopic in order to remove sweat and moisture from the wearer and improve the wearer's comfort, but the above-mentioned synthetic fibers have almost no hygroscopicity. In this regard, acrylate-based fibers obtained by chemically modifying acrylic fibers have excellent moisture absorption and release properties despite being synthetic fibers, and fiber structures made from such fibers can effectively absorb moisture and water, making them suitable for use in environments where moisture and water are undesirable.

[0004] Regarding such acrylate-based fibers, for example, Patent Document 1 reports a fiber structure containing high-whiteness, hygroscopic synthetic fibers obtained by subjecting acrylic fibers made of acrylonitrile-based polymers containing less than 5% by weight of (meth)acrylic acid ester compounds as copolymerization components to crosslinking introduction treatment with a hydrazine-based compound, hydrolysis, and reduction treatment. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4058677 Summary of the Invention [Problem to be solved by the invention]

[0006] However, fiber structures such as nonwoven fabrics are often required to have elasticity in addition to moisture absorption properties. Although acrylate-based fibers have excellent moisture absorption properties, they have poor recovery properties after stretching, and therefore nonwoven fabrics made from these fibers cannot be suitably used in applications requiring elasticity, limiting the range of applications. [Means for solving the problem]

[0007] As a result of intensive research into achieving the above-mentioned object, the inventors have discovered that a needle-punched nonwoven fabric containing a mixture of acrylate-based fibers and crimped polyester fibers, which has an elongation recovery rate, elongation rate and thickness within specific ranges as described below, combines moisture absorption and stretchability, and have arrived at the present invention.

[0008] That is, the present invention is achieved by the following means. (1) A needle-punched nonwoven fabric containing a mixture of acrylate fibers having 1 to 10 mmol / g carboxyl groups and crimped polyester fibers, the acrylate fiber nonwoven fabric having an elongation recovery rate of 65 to 100%, an elongation rate of 15 to 80%, and a thickness of 1.0 to 10 mm. (2) Weight per unit area: 70 to 200 g / m 2 The acrylate fiber nonwoven fabric according to (1), (3) The acrylate fiber nonwoven fabric according to (1), wherein the content of the acrylate fiber is 10 to 50% by weight. (4) The acrylate fiber nonwoven fabric according to (1), wherein the acrylate fiber has a fineness of 1 to 10 dtex. (5) The acrylate fiber nonwoven fabric according to (1), wherein the fineness of the crimped polyester fiber is 2 to 8 dtex. (6) The acrylate fiber nonwoven fabric according to (1), wherein the crimped polyester fiber is a composite of two types of polyester having different shrinkage properties. Effect of the Invention

[0009] The acrylate-based fiber nonwoven fabric of the present invention has both hygroscopicity and elasticity, and can be suitably used in applications where elasticity is required, which was a problem in the past. In addition, by incorporating the nonwoven fabric into a fiber structure, the fiber structure can be imparted with hygroscopicity while suppressing a decrease in elasticity. For example, when the nonwoven fabric is used as a material for clothing, the fabric can absorb sweat and moisture emitted by the wearer and stretch to follow the movement of the body. In particular, the fabric can be suitably used for sportswear and work clothes worn during sports and physical work, which involve a lot of physical movement and tend to cause a lot of sweating. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Each of the fibers employed in the present invention will be described in detail below.

[0011] The acrylate fiber having a carboxyl group used in the present invention has a carboxyl group in the fiber, and the fiber exhibits hygroscopicity by adsorbing moisture with the carboxyl group. Here, the lower limit of the amount of carboxyl groups contained in the acrylate fiber is 1 mmol / g, preferably 2.5 mmol / g, and more preferably 4 mmol / g. If the amount of carboxyl groups is less than 1 mmol / g, sufficient hygroscopicity may not be obtained. The upper limit is 10 mmol / g, preferably 8 mmol / g, and more preferably 7 mmol / g. If the amount of carboxyl groups is more than 10 mmol / g, the fiber may excessively adsorb water and swell, which may deteriorate the fiber properties and make it difficult to process or use.

[0012] The counter ion of the carboxyl group may be one or more selected according to the required characteristics from cations of alkali metals such as sodium, potassium, lithium, etc., cations of alkaline earth metals such as magnesium, calcium, etc., ammonium ions, hydrogen ions, etc. When a carboxyl group having a counter ion other than a hydrogen ion (hereinafter referred to as a salt-type carboxyl group) is present, the saturated moisture absorption amount and moisture absorption rate become larger, improving comfort when used as a padding material.

[0013] The method for obtaining the acrylate fiber is not particularly limited, and may be produced by a known method such as the method for producing an acrylate fiber by crosslinking and hydrolysis of an acrylic fiber described in JP-A-2000-314082, or may be a commercially available product. Examples of such commercially available products include Ex (registered trademark), Dismel (registered trademark), Moisfine (registered trademark), and Moiscare (registered trademark), which are acrylate fibers manufactured by Toyobo Co., Ltd., and Sunburner (registered trademark), which is an acrylate fiber manufactured by Teijin Frontier Co., Ltd.

[0014] The lower limit of the fineness of the acrylate-based fiber is preferably 1 dtex, more preferably 2 dtex. If the fineness is less than 1 dtex, the strength may be insufficient, and processing into the nonwoven fabric may be difficult. The upper limit is preferably 10 dtex, more preferably 7 dtex. If the fineness is more than 10 dtex, the texture of the nonwoven fabric may be deteriorated.

[0015] Next, crimped polyester fibers will be described.

[0016] The crimped polyester fiber used in the present invention has elasticity resulting from its own crimping, and can impart elasticity to a nonwoven fabric containing the polyester fiber.

[0017] The lower limit of the fineness of the crimped polyester fiber is preferably 2 dtex, more preferably 3 dtex. If the fineness is less than 2 dtex, spinnability and carding machine passability may be reduced. The upper limit is preferably 8 dtex, more preferably 7 dtex. If the fineness is more than 8 dtex, the texture of the nonwoven fabric may become rough, making it unsuitable for clothing applications.

[0018] There is no particular restriction on the crimp of the crimped polyester fiber, but from the viewpoint of bulkiness and stretchability, it is preferable to select a three-dimensional crimp such as a coil or spiral crimp.

[0019] As a method for causing the crimped polyester fiber to exhibit three-dimensional crimping, for example, a method using a composite fiber made of two polyester polymer components with different thermal shrinkage rates can be mentioned. When the composite fiber is subjected to heat treatment, the two polymers constituting the composite fiber undergo thermal shrinkage according to their respective thermal shrinkage rates, resulting in the composite fiber exhibiting three-dimensional shrinkage. Here, the combination of two polyester polymer components used in the composite fiber may be such that the two components have different thermal shrinkage rates. For example, two types of polyester polymers may be selected from polyester polymers with different thermal shrinkage rates, such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, or a combination of a polyester polymer, such as polyethylene terephthalate and modified polyethylene terephthalate, and a polymer whose thermal shrinkage rate has been changed from that of the original polymer by modifying the polymer or changing the degree of polymerization, may be mentioned. In addition, examples of the structure of the composite fiber include a side-by-side structure, which is a two-layer structure in which two types of polymers are bonded together, and an eccentric core-sheath structure, which is a core-sheath structure in which the core is arranged at a position shifted from the fiber axis.

[0020] The method for obtaining the crimped polyester fibers is not particularly limited, and a known method for producing two types of polyester polymers using a conjugate spinning device may be adopted, or a commercially available product may be used.

[0021] The acrylate fiber nonwoven fabric of the present invention is a needle-punched nonwoven fabric containing a mixture of the above-mentioned carboxyl group-containing acrylate fiber and crimped polyester fiber, and is characterized in that the elongation percentage, elongation recovery percentage and thickness described below fall within specific numerical ranges.

[0022] As described above, the acrylate fiber nonwoven fabric of the present invention is a needle-punched nonwoven fabric. As a type of nonwoven fabric, spunlace nonwoven fabric and spunbonded nonwoven fabric are well known in addition to needle-punched nonwoven fabric. However, in spunlace nonwoven fabric, water is used to intertwine the fibers, so the acrylate fibers swell with water, weakening their strength, and the fibers become finer and fall off, which is undesirable. In addition, in spunbonded nonwoven fabric, the fibers are fixed and difficult to deform, so the elongation rate and elongation recovery rate decrease, and the texture becomes hard, which is undesirable. In contrast, needle-punched nonwoven fabric is a dry nonwoven fabric, and the fibers are not fixed, so it is suitable for the present invention.

[0023] The elongation percentage of the acrylate fiber nonwoven fabric of the present invention is 15% as a lower limit, and preferably 20%. If the elongation percentage is less than 15%, sufficient elongation cannot be obtained, and there is a risk of restricting body movement when used in clothing, etc. The upper limit is 80%, preferably 60%, and more preferably 50%. If the elongation percentage exceeds 80%, it becomes difficult to achieve an elongation recovery percentage of 65% or more, as described below, and as a result, stretchability is lost, and there is a risk of the fabric being uncomfortable to wear when used in clothing.

[0024] The lower limit of the stretch recovery rate of the acrylate fiber nonwoven fabric is 65%, and preferably 70%. If the stretch recovery rate is less than 65%, the conformability may decrease when used in clothing, etc., and comfort may be impaired. There is no particular upper limit, but realistically, 100% is the upper limit. Here, the stretch recovery rate is a value indicating elasticity against stretching, and is determined by the method described in the examples below. It can be said that the higher the stretch recovery rate, the easier the nonwoven fabric will return to its original shape even when stretched.

[0025] The lower limit of the thickness of the acrylate fiber nonwoven fabric is 1.0 mm, and preferably 2.0 mm. If the thickness is less than 1.0 mm, there is a risk that sufficient strength cannot be obtained. The upper limit is 10 mm, and preferably 6.0 mm. If the thickness exceeds 10 mm, there is a risk that the breathability and wearing comfort of the fabric when made into clothing may decrease.

[0026] The basis weight of the acrylate fiber nonwoven fabric is 70 g / m 2 is preferred, and 100 g / m 2 More preferably, the weight is 70 g / m 2 If the density is less than this, sufficient moisture absorption may not be obtained. The upper limit is 200 g / m 2 is preferred, and 160 g / m 2 More preferably, the weight is 200 g / m 2 If the temperature exceeds this range, the breathability and flexibility of the material will decrease, which may result in a decrease in comfort when used in clothing, etc.

[0027] The acrylate-based fiber nonwoven fabric has excellent moisture absorption and release properties, and from the viewpoint of maintaining an appropriate humidity level around the nonwoven fabric, the moisture absorption rate difference determined by the method described in the Examples below is preferably 5.0% as a lower limit, and more preferably 10%.

[0028] The content of the acrylate fiber in the acrylate fiber nonwoven fabric is preferably 10% by weight as a lower limit, more preferably 20% by weight, from the viewpoint of obtaining sufficient moisture absorption of the acrylate nonwoven fabric, and is preferably 50% by weight as an upper limit, more preferably 40% by weight, from the viewpoint of obtaining sufficient strength and processability of the acrylate fiber.

[0029] In addition, the content of the crimped polyester fiber in the acrylate fiber nonwoven fabric is preferably 50% by weight, more preferably 60% by weight, from the viewpoint of obtaining sufficient stretchability of the acrylate fiber nonwoven fabric, and is preferably 90% by weight, more preferably 80% by weight, from the viewpoint of ensuring the content of the hygroscopic acrylate fiber in the acrylate fiber nonwoven fabric.

[0030] The acrylate fiber nonwoven fabric may contain fibers other than those mentioned above, so long as the object of the present invention is not hindered. Examples of fibers to be contained include non-shrinkable polyester fibers, acrylic fibers, synthetic fibers such as rayon, natural fibers such as cotton, hemp, and wool, and inorganic fibers such as glass fibers. The upper limit of the content of the fibers is preferably 40% by weight, and more preferably 20% by weight.

[0031] The method for producing the acrylate-based fiber nonwoven fabric may employ a conventionally known method, for example, a method in which the acrylate-based fiber and the crimped polyester fiber are mixed, a web is formed using a carding machine or the like, the fibers are entangled using needle punching, and then the crimp of the crimped polyester fiber is expressed by heat treatment using a hot air dryer or the like, and then a calendaring process is performed as necessary to obtain a nonwoven fabric. Here, if a carding machine or needle punching process is performed in a state in which the crimp has been expressed in the crimped polyester fiber, the crimp may become entangled in the needles of the carding machine or needle punching machine, causing problems in processing, and therefore it is desirable to express the crimp after needle punching the web.

[0032] The acrylate fiber nonwoven fabric of the present invention has both hygroscopicity and elasticity and can be suitably used as a material for clothing and bedding, and can be particularly suitably used for sports clothing, work clothes and bed pads. EXAMPLES

[0033] Examples are shown below to facilitate understanding of the present invention, but these are merely illustrative and the gist of the present invention is not limited to these.

[0034] <Method for measuring the amount of carboxyl groups> Approximately 1 g of the sample fiber was immersed in 50 mL of 1 mol / L hydrochloric acid solution for 30 minutes. The sample was then immersed in water with a bath ratio of 1:500. After 15 minutes, it was confirmed that the bath pH was 4 or higher, and the sample was thoroughly dried (if the bath pH was less than 4, it was washed with water again). Next, approximately 0.2 g of the sample after the drying was precisely weighed (W [g]), 100 mL of water was added, and further, 15 mL of 0.1 mol / L sodium hydroxide aqueous solution, 0.4 g of sodium chloride and phenolphthalein were added and stirred. After 15 minutes, the sample and the filtrate were separated by filtration, and the filtrate was titrated with 0.1 mol / L hydrochloric acid aqueous solution until the color of phenolphthalein disappeared, and the amount of hydrochloric acid aqueous solution consumed (V [mL]) was obtained, and the amount of carboxyl groups was calculated using the following formula. Carboxyl group amount [mmol / g] = (0.1 x 15 - 0.1 x V) / W

[0035] <Method for measuring elongation recovery rate> The measurements and calculations were carried out in accordance with the JIS-L1096:2010-8.16.2-D method (repeated constant elongation method) with a constant elongation of 30%, one repetition, a gripping distance of 100 mm, and a tensile speed of 100 mm / min.

[0036] <Method of measuring elongation rate> The initial load was 49 mN, the interval was 200 mm, and the applied load was 931 mN. Other than that, measurements and calculations were carried out in accordance with JIS-L1096:2010-8.16.1-B method (constant load method for woven fabrics).

[0037] <Measuring method for basis weight> A sample nonwoven fabric of 100 x 100 mm was dried at 105°C for 2 hours, and then its weight (Y [g]) was measured and calculated according to the following formula. Weight [g / m 2 ]=Y / (0.1×0.1)

[0038] <How to measure thickness> The thickness of a 100 x 100 mm sample nonwoven fabric was measured using a thickness gauge FS-60DS manufactured by Daiei Scientific Instruments Co., Ltd. The measurement method was in accordance with "JIS-L1913:2010-6.1.1-A method" except that measurements were taken at three different points on one sample nonwoven fabric.

[0039] <Method of measuring moisture absorption difference> A sample nonwoven fabric of 100×100 mm was dried in a thermostatic dryer at 80° C. for 16 hours, and then cooled in a desiccator for 15 minutes (sample weight: W0 [g]). After that, it was left in a thermostatic hygrostat set at 20° C.×95% RH until it reached equilibrium moisture absorption, and the mass after equilibrium moisture absorption was measured (W1 [g]), and the moisture absorption rate A was calculated using the following formula. After that, the nonwoven fabric was left in a thermostatic hygrostat set at 20° C.×50% RH until it reached equilibrium moisture absorption, and the mass after equilibrium moisture absorption was measured (W2 [g]), and the moisture absorption rate B was calculated using the following formula. Finally, the moisture absorption rate difference was calculated using the obtained moisture absorption rates A and B according to the following formula. Note that "20° C.×40% RH" and "20° C.×90% RH" refer to an atmosphere in which the temperature is 20° C. and the relative humidity is 40% and 90%, respectively. Moisture absorption rate A(%)={(W1-W0) / W0}×100 Moisture absorption rate B(%)={(W2-W0) / W0}×100 Moisture absorption rate difference (%) = Moisture absorption rate A - Moisture absorption rate B

[0040] Example 1 30 parts by weight of acrylate fiber (fineness 5.1 dtex, fiber length 48 mm, carboxyl group amount 6.5 mmol / g) manufactured by Nippon Exlan Co., Ltd. and 70 parts by weight of crimped polyester fiber (fineness 6.6 dtex, fiber length 51 mm) manufactured by Toray Industries, Inc. were uniformly mixed and spread using a fiber spreader, then passed through a carding machine to prepare a carded web. The carded web was entangled using a needle punch, and then heated in an atmosphere of 180°C for 3 minutes to express the crimp of the crimped polyester fiber. Finally, the nonwoven fabric of Example 1 (basis weight 128 g / m) was produced by calendering. 2 , thickness 2.8 mm).

[0041] Comparative Example 1 A nonwoven fabric (basis weight 101 g / m) of Comparative Example 1 was produced in the same manner as in Example 1, except that the crimped polyester fiber was changed to a non-crimped polyester fiber (fineness 6.6 dtex, fiber length 51 mm). 2 , thickness 2.4 mm).

[0042] Comparative Example 2 A nonwoven fabric of Comparative Example 2 (basis weight 130 g / m) was prepared in the same manner as in Example 1, except that the fibers used were the non-crimped polyester fibers of Comparative Example 1 only. 2 , thickness 2.5 mm).

[0043] Various measurements were carried out on the above-mentioned Examples and Comparative Examples, and the results of the measurement of the elongation recovery rate and elongation rate are shown in Table 1.

[0044] [Table 1]

Claims

1. The needle-punched nonwoven fabric contains a mixture of acrylate fibers having 1 to 10 mmol / g of carboxyl groups and crimped polyester fibers, and has a stretch recovery rate of 65 to 100%, an elongation rate of 15 to 80%, and a thickness of 1.0 to 10 mm.

2. Weight per unit area: 70 to 200 g / m ２ 2. The acrylate fiber nonwoven fabric according to claim 1,

3. 2. The acrylate fiber nonwoven fabric according to claim 1, wherein the content of the acrylate fiber is 10 to 50% by weight.

4. 2. The acrylate fiber nonwoven fabric according to claim 1, wherein the acrylate fiber has a fineness of 1 to 10 dtex.

5. 2. The acrylate fiber nonwoven fabric according to claim 1, wherein the fineness of the crimped polyester fiber is 2 to 8 dtex.

6. 2. The acrylate fiber nonwoven fabric according to claim 1, wherein the crimped polyester fiber is a composite of two types of polyester having different shrinkage properties.

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