JP3154286B2 - Hygroscopic nonwoven fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hygroscopic nonwoven fabric.

[0002]

2. Description of the Related Art Various nonwoven fabrics have already been proposed, but none of them have high hygroscopicity and have hygroscopicity. For example, cotton and wool disclosed in JP-A-60-146004 show relatively high hygroscopicity but are insufficient. On the other hand, natural leather exhibits excellent moisture absorption and release properties, and is widely used in shoes, clothing and the like. However, from the viewpoint of nature protection, it is not permissible to rely on natural leather. In addition, natural leather can be three-dimensionally formed by a processing method, but three-dimensional molding cannot be performed with a non-stretchable nonwoven fabric.

[0003] Non-woven fabrics and woven / knitted fabrics having enhanced moisture permeability due to insufficient moisture absorption are already on the market, but they are inferior to moisture absorption. In addition, it is more preferable that the nonwoven fabric is rich in hygroscopicity and absorbs sweat when sweating.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive hygroscopic nonwoven fabric which can be replaced with natural leather.

[0005]

Means for Solving the Problems The present inventors have studied high-absorbency and high-absorbency fibers which have high water absorbency and high water absorbency with respect to water, and have studied the preparation and form thereof to complete the present invention.

[0006] hygroscopicity nonwoven fabric of the present invention is 30 ° C., Ri der hygroscopicity 30% by weight or more at 80% relative humidity, saline
Absorbs water from 1200 wt% to less than 3000 wt%
Reacts with a monomer having a carboxylic acid group
Hydroxyl groups and / or amino groups capable of forming
Monomer with a carboxylic acid group and an alkali metal carboxylate
Contains 10 to 50% by weight of superabsorbent fibers cross-linked by heat by copolymerizing the monomer having the fibers, and the fibers constituting the nonwoven fabric are bonded to each other by rubber , and have an elastic modulus of 10% or more.
It is characterized by having .

Further, the hygroscopic nonwoven fabric of the present invention has a temperature of 30 ° C.
Ri der hygroscopicity 30% by weight or more at 80% relative humidity,
1200% by weight or more and less than 3000% by weight of physiological saline
A monomer having a carboxylic acid group that absorbs water and a carboxylic acid group
Hydroxyl groups which can react with
Or a monomer having an amino group and an alkali gold carboxylate
Nonwoven fabric containing 10-50% by weight of superabsorbent fibers crosslinked by heat by copolymerizing a monomer having a genus base and having an interlining of 20% or more (for example, having a 99% elongation recovery rate) And has an elastic modulus of 10% or more. The term “elastic modulus” as used herein means an elongation rate that indicates a recovery rate of 80% or more when stretched.

The superabsorbent fiber used in the present invention has a moisture absorbency of 30% by weight or more at 30 ° C. and a relative humidity of 80%. Ma
In addition , copolymerization of a monomer having a carboxylic acid group, a monomer having a hydroxyl group and / or an amino group capable of forming a cross-linking by reacting with the carboxylic acid group, and a monomer having an alkali metal carboxylate is performed. And a fiber cross-linked by heat, and a physiological saline of 1200% by weight or more,
It absorbs less than 3000% by weight of water. Also preferably, one side of the hygroscopic nonwoven fabric is combined with a film, a porous urethane-coated nonwoven fabric, or another nonwoven fabric.

As the monomer having a carboxylic acid group of the superabsorbent fiber used in the present invention, for example, acrylic acid (hereinafter referred to as "A
A ". ), Methacrylic acid, maleic acid, and the like.

As the monomer having an alkali metal carboxylate, for example, alkali metal salts such as AA, methacrylic acid and maleic acid are used. As the alkali metal, sodium (hereinafter abbreviated as "Na"), potassium and the like are used. The ratio of the monomer having a carboxylic acid group to the monomer having a carboxylic acid alkali metal base is 1/1 to 1
1/10 is preferred. The total of the monomer having a carboxylic acid group and the monomer having a carboxylic acid alkali metal base is usually 70% by weight to 99.5% by weight. Preferably 8
0% by weight or more. If it is less than 70% by weight, the water absorption and the water absorption of the physiological saline are insufficient.

As the monomer having a hydroxyl group,
For example, hydroxyethyl methacrylate (hereinafter "HEM")
A ". ), Hydroxypropyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, glyceryl monomethacrylate, glyceryl monoacrylate, and the like.

Examples of the monomer having an amino group include dimethylaminoethyl acrylate (hereinafter abbreviated as "AEA"), diethylaminoethyl acrylate, diethylaminoisopropyl methacrylate and the like.

Each of these monomers may be used in a plurality of types. The monomer having a hydroxyl group and / or an amino group is not more than an equivalent of free acrylic acid,
% By weight or more. If it is less than 0.5% by weight, crosslinking is insufficient.

In addition to the above monomers, other vinyl monomers such as vinyl acetate (hereinafter referred to as "V
A ". ), Acrylonitrile and the like may be used. The amount of monomer for plasticization is not more than 30% by weight.

The polymerization method used in the present invention is not particularly limited, but water-based polymerization may be used as long as the monomer composition is water-soluble. Sodium persulfate, which is generally used, may be used as the polymerization initiator.

The spinning method used in the present invention is preferably general dry spinning. In the case of wet spinning, water cannot be used as a coagulant and must be used in an organic solvent system.

For example, after dry spinning, the water content is 10% by weight.
The film is stretched 1.3 times or more by dry heat while remaining as described above, and then crosslinked by dry heat. Crimping and cutting are appropriately performed. When the fiber is stretched 1.3 times or more by dry heat with 10% by weight or more of water remaining, the fiber strength is improved. Fibers having a large molecular weight have a large water absorption, but on the other hand, are difficult to be stretched due to a large molecular weight, and conversely if the molecular weight is too large, the fiber strength is low.

The superabsorbent fiber used in the present invention produced by the above method absorbs 1200% by weight or more of physiological saline. Preferably it is 1800% or more. 3000% by weight
If it exceeds, the fiber strength decreases. It is a highly hygroscopic fiber having a hygroscopicity of 30% by weight or more at 30 ° C. and a relative humidity of 80%. If the hygroscopicity of the superabsorbent fiber is less than 30% by weight, the hygroscopicity of the nonwoven fabric is insufficient. The water absorption of super absorbent fiber is 1
If it is less than 200% by weight, water absorption is insufficient.

The method for producing the nonwoven fabric used in the present invention may be a general method. For example, needle punch method, air lay method,
A method of blending heat-fused fibers may be used.

In addition, rubber can be impregnated to increase the elongation modulus. The type of rubber is not particularly limited. For example, natural rubber, synthetic rubber such as IR, BR, EPM,
IIR, CR, NBR, SBR, ECO, CPE, AC
M, but is not limited to this. In addition, acrylic resins, urethane resins, vinyl acetate resins and the like can also be used. Rubber is better than resin in terms of extensibility. These rubbers and resins can be used as emulsions. The selection of the resin should be appropriately selected in consideration of the elasticity, hardness and the like depending on the application.

The amount of rubber or resin is preferably 3 to 50% by weight based on the weight of the nonwoven fabric. If it is less than 3% by weight, the properties to be imparted, for example, rubber elasticity, hardness, etc., are insufficient. If it exceeds 50% by weight, water absorption and hygroscopicity are impaired.

The resin used in the present invention may be a commercially available resin. In order to process the resin into a water-absorbent nonwoven fabric, the emulsion is diluted to an amount corresponding to the amount of water absorbed, or a suitable amount of water is previously impregnated into the water-absorbent nonwoven fabric. If the emulsion is not impregnated after the formation, adhesion spots are likely to occur. After the adhesion, it may be squeezed with a mangle or the like, dried and baked. It can be impregnated with a spray, but immersion is preferable because it has less unevenness. Further, a pigment, a flame retardant, or the like can be mixed with a resin emulsion or the like.

The nonwoven fabric of the present invention can be laminated with other nonwoven fabric materials. Elastic nonwoven fabrics can be three-dimensionally formed by utilizing their elasticity and heat softening properties. The drying temperature should take into account the heat resistance of the fibers used in the nonwoven fabric.

Further, there is also a method in which an elastic nonwoven fabric is used as an interlining by a needle punch method. Such non-woven fabrics
For example, there is "espansione" which is commercially available from Kanebo Co., Ltd. as a melt-type spunbond. You may use together with the method of impregnating rubber. The elasticity recovery power is improved.

The hygroscopic nonwoven fabric of the present invention contains 10 to 50% by weight of a hygroscopic superabsorbent fiber. Preferably 20
% By weight or more. It is more preferably at least 30% by weight. If the content is less than 10% by weight, the moisture absorption and water absorption capabilities of the nonwoven fabric are insufficient for practical use. If it exceeds 50% by weight, the strength is insufficient.

The density of the non-woven fabric used in the moisture-absorbing non-woven fabric of the present invention, particularly at the portion where water is absorbed, is 0.02 to 0.10 gr / c
About m ³ is preferable. If the density is too high, the hygroscopicity and the water absorption are reduced. If the density is too low, the strength will be insufficient.

The heat-fused fibers used in the nonwoven fabric of the present invention are not particularly limited. For example, there are commercially available fibers in which the core is made of polypropylene, the sheath is made of polyethylene, and the core is made of polyester, and the sheath is made of polyethylene.

The hygroscopic nonwoven fabric of the present invention may have a multilayer structure. For example, a nonwoven fabric layer coated with urethane may be bonded and laminated to make up the surface.

In general, since urethane coatings are porous, they are produced by a wet method using water as a coagulating solvent, and cannot be directly processed into a nonwoven fabric containing superabsorbent fibers. However, another nonwoven fabric or knitted fabric may be laminated between the urethane coating layer and the hygroscopic nonwoven fabric. If there is no intermediate layer, the moisture-absorbent nonwoven fabric absorbs water and swells, so that the urethane coating becomes uneven, which does not work. If the urethane coating is performed with an organic solvent (for example, isopropanol) or a coagulating liquid containing the organic solvent, the intermediate layer may not be provided.

The urethane used for the nonwoven fabric of the present invention is not particularly limited. As the diisocyanate, for example, tolylene diisocyanate or the like is used. There are polyols, polyesters, polycarbonate types and the like, but depending on the application, the characteristics of urethane may be considered.

The urethane of the surface layer is preferably porous and has pores communicating therewith. Further, although it is used more often than ever to improve water absorption, a hole may be partially formed in urethane for the purpose of preventing slip. Further, embossing or the like may be performed.

The reinforcing film or nonwoven fabric used in the present invention is not particularly limited as long as it has sufficient strength. For example, there is a polyester spunbond nonwoven fabric. Although an adhesive is used for multi-layering, it is preferable to use rubber.

The hygroscopic nonwoven fabric of the present invention can be freely colored by pre-coloring the fibers. Further, the rubber to be impregnated may be colored. Further, an antibacterial agent having silver supported on an inorganic substance may be contained in fibers, rubber or urethane to impart antibacterial properties.

[0034]

The hygroscopic nonwoven fabric of the present invention has excellent hygroscopicity,
It is an inexpensive hygroscopic nonwoven fabric that has a surface structure, texture and elasticity and can be replaced with natural leather.

[0035]

EXAMPLES Further details will be described in Examples. In Examples, “%” is “% by weight” unless otherwise specified.

The physiological saline water absorption of cotton having high water absorbency is
It was measured according to DIN 53814. The water absorption of the nonwoven fabric is 2 psi. Was applied, and the weight was measured and calculated from the difference from the weight before water absorption. The composition of the super absorbent fiber is
The content of the alkali metal salt was measured by X-ray fluorescence analysis. The monomer composition was measured by IR for a sample dried in vacuum. The polymerization rate was measured by Iatroscan MK5 (TLC / F
ID). The content of the superabsorbent fiber was determined from the dry weight after dissolving other fibers and washing. Fiber strength and the like were measured according to JIS L1015. The moisture absorption rate of high water absorption fiber is 1
It was determined from the weight after standing overnight and the absolute dry weight.

Production Example 1 A monomer having a polymerization composition shown in Table 1 having a monomer concentration of 15% and a polymerization temperature of 5
Aqueous solution polymerization was carried out at 5 ° C. for 4 hours using sodium persulfate as a polymerization initiator. The polymerization rate was measured by TLC, and as a result, there was no peak of the monomer. Therefore, the polymerization rate was practically 100%. Therefore, the polymerization composition of the obtained polymer coincided with the polymerization charge composition. Next, the obtained polymer dope was concentrated, and the viscosity was adjusted at 50 ° C. to near 90 poise.
It is spun into a dry hot nitrogen stream and dried in the same manner as a commonly used dry spinning, and the yarn having a moisture content of 20% is dried at 100 ° C.
And stretched 1.5 times. After crimping with a gear crimper, a dry heat cross-linking treatment was performed at 120 ° C. for 5 minutes and cut to obtain a 10 denier, 51 mm high water-absorbing fiber.

Table 1 shows the moisture absorption and the water absorption of the resulting superabsorbent fibers. The resulting fiber had a mechanical strength of 1 gr / denier or more and could be mounted on a normal card. Composition No. Sample No. 4 had a high water absorption but lacked crosslinking and was partially dissolved in water. Composition No. 5 was insufficient in water absorption.

Production Example 2 Composition No. 1 produced in Production Example 1 2 super-absorbent fiber, commercially available core polyester, sheath polyester, heat-fused fiber 3 denier 51 mm, which is fused at 130 ° C., and commercially available polyester cotton semi-dal 3 denier 51 mm, are blended in the ratios shown in Table 2 and are generally used. A nonwoven fabric was manufactured by the needle punching method. That is, after blending, carding and needle punching were performed to produce a nonwoven fabric having a basis weight of 200 gr / m ² . The thickness of the obtained nonwoven fabric was about 0.9 mm. Table 2 shows the mixing ratio of this nonwoven fabric.

Example 1 NBR manufactured by Nippon Zeon Co., Ltd.
Resin emulsion (Nipol 1571) is impregnated with 5% of solid content by a dipping method, dried with hot air at 100 ° C. for 10 minutes,
I baked. Table 3 shows the water absorption and the moisture absorption of the obtained nonwoven fabric. Water absorption and hygroscopicity due to resin processing were almost the same as unprocessed products.

Example 2 Composition No. 1 produced in Production Example 1 2 super absorbent fibers 30%
And commercially available polyester cotton semi-dal 3 denier 51mm7
0% was prepared, and a nonwoven fabric was manufactured by a commonly used needle punching method using a urethane nonwoven fabric “espansione” having a basis weight of 80 gr / m ² as an interlining. The basis weight of the obtained nonwoven fabric was 200 gr / m ² . The thickness of the nonwoven fabric after embossing at 100 ° C. was 2 mm. The water absorption of this nonwoven fabric was 800%. The tensile elongation in the machine direction of the obtained nonwoven fabric was 50% or more. These nonwoven fabrics were impregnated with the above-mentioned NBR resin emulsion at a solid content of 5% by an immersion method, dried at 120 ° C. for 20 minutes with hot air, and baked. The water absorption of this non-woven fabric is 780%
Met. The obtained nonwoven fabric had an elongation of 50% or more in the machine direction, and had a stretch elastic modulus of 15%.

Example 3 Formulation No. of Example 1 30g / m of 3d51mm heat-sealed polyester core-sheath type to resin-processed non-woven fabric of 4
The nonwoven fabric of No. ² was heat bonded with an emboss roller as an intermediate layer. Next, a 15% dimethylformamide solution of polyurethane was coated with a calender roller to a thickness of 1 mm. This non-woven fabric is dimethylformamide 15% water 85%
In a coagulation bath at 25 ° C. to form a porous urethane layer, and then dried. The urethane layer of the obtained nonwoven fabric had few irregularities, and its water absorption and moisture absorption were almost the same as those of the unprocessed product. On the other hand, No. When urethane coating was performed on the nonwoven fabric of No. 4, irregularities were conspicuous on the urethane surface, and the adhesion state of the urethane layer was not good.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-263615 (JP, A) JP-A-55-6590 (JP, A) JP-A-5-33255 (JP, A) (58) Field (Int. Cl. ⁷ , DB name) D04H 1/00-18/00 EPAT (QUESTEL) WPI / L (QUESTEL)

Claims (4)

(57) [Claims] 1. A 30 ° C., Ri der hygroscopicity 30% by weight or more at 80% relative humidity, 1200 wt% or saline
Above, a carboxylic acid group that absorbs less than 3000% by weight of water
React with carboxylic acid groups to form crosslinks
Having a hydroxyl group and / or an amino group
And a monomer having an alkali metal carboxylate
Moisture combined, a high absorption water soluble fibers crosslinked by heat contained 10 to 50 wt%, they are bonded by the rubber to each other fibers constituting the nonwoven fabric, which is characterized by having stretch elasticity modulus of more than 10% Nonwoven fabric. 2. A 30 ° C., Ri der hygroscopicity 30% by weight or more at 80% relative humidity, 1200 wt% or saline
Above, a carboxylic acid group that absorbs less than 3000% by weight of water
React with carboxylic acid groups to form crosslinks
Having a hydroxyl group and / or an amino group
And a monomer having an alkali metal carboxylate
Combined, a high absorption water soluble fibers crosslinked by heat contained 10 to 50 wt%, interlining is a nonwoven fabric having 20% or more stretch, characterized by having stretch elasticity modulus of more than 10% Hygroscopic nonwoven fabric. 3. The hygroscopic nonwoven fabric according to claim 1, wherein one side of the hygroscopic nonwoven fabric is composited with a porous urethane-coated nonwoven fabric. 4. The hygroscopic nonwoven fabric according to claim 1, wherein one side of the hygroscopic nonwoven fabric is composited with a film or another nonwoven fabric.