JP2002194678A - Fiber sheet for artificial leather - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide the same appearance and wind as those obtained by impregnating a polymer elastic solution under aqueous processing conditions without requiring special equipment necessary for obtaining high-grade suede. Provided is a leather-like fiber sheet having a combination. SOLUTION: This is a porous fiber aggregate made of fibers having a single-fiber fineness of 3.3 dtex or less containing 10 to 100% by mass of wet-heat-adhesive crimped fibers, and a large number of cells are formed inside the aggregate. A fiber sheet for artificial leather comprising a porous fiber aggregate having a void portion and at least a part of the fibers constituting the aggregate are heat-bonded by wet-heat-adhesive crimped fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber sheet for artificial leather, and more particularly, to a fiber sheet having at least one surface formed by self-fusion with a wet heat-bondable crimped fiber. The present invention relates to a novel fiber sheet for artificial leather.

[0002]

2. Description of the Related Art A large number of product items called artificial suede have been proposed so far. Among them, those obtained by impregnating a fiber sheet in which ultrafine fibers are entangled with a urethane elastic solution have a texture and a structural surface. , It is very similar to natural leather, and its position as a luxury suede has been firmly established. However, there is a problem that processing equipment is limited in that a solvent must be used in the processing step.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, does not require specific equipment necessary for obtaining a high-grade suede, and furthermore, a polymer under aqueous processing conditions. An object of the present invention is to provide an artificial leather fiber sheet having the same appearance and feeling as those obtained by impregnating an elastic solution.

[0004]

That is, the present invention relates to a porous fiber aggregate comprising a fiber having a single fiber fineness of 3.3 dtex or less containing 10 to 100% by mass of a wet-heat-adhesive crimped fiber. A number of cellular voids are present inside the body, and at least a part of the fibers constituting the aggregate is an artificial leather made of a porous fiber aggregate heat-bonded by wet-heat-adhesive crimped fibers. Fiber sheet.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a porous fiber assembly constituting a fiber sheet for artificial leather of the present invention will be described. In the present invention, the wet-heat-bonded crimped fiber contained in the fiber assembly is a crimped fiber containing a polymer component that is softened by hot water at about 95 to 100 ° C. and adheres to self-adhesive or other fibers. . The crimped form of the crimped fiber is a planar zigzag crimp, a three-dimensional crimp by false twist, a side-by-side type composite fiber, an eccentric core-sheath type composite fiber, an asymmetric cooling fiber, and the like. Although not particularly limited, such as crimping, it is preferably a fiber having a three-dimensional crimp from the viewpoint of bulkiness and flexibility of the porous fiber aggregate, and particularly preferably false twisted crimped fiber. Used. On the other hand, in the case of straight yarn such as raw silk, the expression of the above-described three-dimensional random coil cannot be obtained, and the bonded portion is not a dot but a lump, and the hand becomes hard. Moreover, even if it has wet heat adhesiveness, a wet heat adhesive crimped fiber which loses crimp by heat treatment is not preferable because the effect of the present invention cannot be obtained. Also, the wet-heat-adhesive crimped fiber has an adhesive component of 100% by mass.
It is difficult to obtain a target structure even if a single yarn (a so-called homofilament) made of is mixed with a regular crimped yarn.

[0006] Such a wet-heat-adhesive crimped fiber preferably has a crimp rate of 5% or more, more preferably a fiber having a crimp rate of 10 to 30%. Crimp rate is 5
%, The formation of the cellular voids described below becomes insufficient, and the bulky fiber aggregate that is the object of the present invention may not be obtained.

As the wet heat adhesive polymer constituting the wet heat adhesive fiber, for example, a copolymer containing nylon 12 or acrylamide as one component, polylactic acid, ethylene-
Examples thereof include a vinyl alcohol-based copolymer, and among them, an ethylene-vinyl alcohol-based copolymer is preferably used. As the ethylene-vinyl alcohol-based copolymer, those obtained by copolymerizing polyvinyl alcohol with 10 to 60 mol% of ethylene residues are preferable, and those obtained by copolymerizing ethylene residues with 30 to 50 mol% are particularly suitable for wet heat bonding. It is preferable in terms of properties. Further, the vinyl alcohol part preferably has a saponification degree of 95 mol% or more. Due to the large number of ethylene residues, it has a unique property that it has wet heat adhesion but is hardly soluble in hot water. The degree of polymerization is not particularly limited, but is preferably about 400 to 1500. In the present invention, after the target porous fiber aggregate is formed, the ethylene-vinyl alcohol-based copolymer can be partially cross-linked for post-processing such as imparting dyeability or fiber modification.

The wet-heat-adhesive crimped fiber used in the present invention may be a fiber composed of the above-mentioned polymer alone, a composite fiber with another thermoplastic polymer, or a fiber composed of another thermoplastic polymer. Fiber whose surface is coated with the polymer may be used. As other thermoplastic polymers, polyester, polyamide, polypropylene and the like can be mentioned, but in terms of heat resistance, dimensional stability, etc., polyesters, polyamides and the like having a higher melting point than ethylene-vinyl alcohol copolymers. It is preferably used.

As the polyester, terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, phthalic acid, α, β- (4-carboxyphenoxy) ethane,
Aromatic dicarboxylic acids such as 4,4'-dicarboxydiphenyl, 5-sodium sulfoisophthalic acid, aliphatic dicarboxylic acids such as azelaic acid, adipic acid, sebacic acid and esters thereof, ethylene glycol, diethylene glycol, 1,3 -Propanediol, 1,4-
Fiber-forming polyesters composed of diols such as butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane-1,4-dimethanol, polyethylene glycol and polytetramethylene glycol. It is preferred that at least mol% be ethylene terephthalate units.

As polyamides, aliphatic polyamides mainly composed of nylon 6, nylon 66 and nylon 12,
Examples thereof include semi-aromatic polyamides, and polyamides containing a small amount of the third component may be used.

In the present invention, when a composite fiber composed of an ethylene-vinyl alcohol copolymer and another thermoplastic polymer is used as the fiber constituting the porous fiber aggregate, the composite ratio is the former: the latter (mass) Ratio) = 10: 90-9
0:10, especially 30:70 to 70:30 is preferred from the viewpoint of spinnability. The composite form is not particularly limited, and a conventionally known composite form can be adopted.However, it is necessary that the ethylene-vinyl alcohol copolymer is present on at least a part of the fiber surface,
It is preferable that 50% or more is exposed. Specific examples of the composite form include a core-sheath type, an eccentric core-sheath type, a multilayer bonding type, a side-by-side type, a random composite type, a radial bonding type, and a fine fiber generation type. The cross-sectional shape of these fibers is not limited to a solid cross-sectional shape such as a round cross-section or an irregular cross-sectional shape, but may be various cross-sectional shapes such as a hollow cross-sectional shape.

[0012] Further, in the case of a fiber in which the surface of another fiber is coated with an ethylene-vinyl alcohol copolymer, it is preferable that the copolymer covers the surface of the other fiber by 1/3 or more. Preferably it is 1/2 or more.

The porous fiber assembly constituting the fiber sheet for artificial leather according to the present invention comprises the above-mentioned wet-heat-adhesive crimped fiber in 10 pieces.
To 100% by mass, preferably 30% by mass.
To 100% by mass, more preferably 50 to 100% by mass
Including. If the wet-heat-adhesive crimped fiber is less than 10% by mass, the fiber will be insufficiently bonded, and the formation of the cellular voids described below will be insufficient.

On the other hand, the fibers other than the wet-heat-adhesive crimped fibers constituting the porous fiber aggregate are not particularly limited, and natural fibers,
Semi-synthetic fibers and synthetic fibers can be used and can be selected according to the purpose, but it is desirable that these fibers also have a crimp equivalent to that of the wet-heat-adhesive crimped fiber.

The fiber constituting the porous fiber assembly has a single fiber fineness of 3.3 dtex or less, and preferably 0.1 dtex or less.
1 to 1.0 dtex. Single fiber fineness is 3.3 dte
When x is exceeded, the appearance and the feeling of the fiber sheet for artificial leather of the present invention become worse when the fiber sheet is used.

The porous fiber assembly according to the present invention is characterized in that it has a large number of cellular voids therein. The cellular void portion referred to in the present invention is a hollow space having a size that can be clearly distinguished from the minute inter-fiber voids of the fibers constituting the porous fiber aggregate, and the shape is spherical to cloud-shaped. And various indefinite forms. Its size has a wide distribution over a major axis of 0.5 to 10 mm. The cellular voids exist alone or in a partially connected state in the porous fiber assembly, and the independent or continuous shape of the cellular voids is not strict, and the sample or its expansion is not limited. This is a shape that can be seen by visual inspection of a photograph, and when viewed microscopically, there may be a continuous cell-shaped void portion that exceeds 10 cm. The porosity of the aggregate can be arbitrarily set depending on the amount of the wet-heat-adhesive crimped fiber used, the accumulation density of the fiber, the conditions of the wet heat treatment, and the like. The ratio is preferably 80% or more, more preferably 90% or more.

Further, a large number of cellular voids are distributed in the aggregate and also exist on the surface of the aggregate. The cellular voids on the surface exist as recesses on the surface and form openings.

The cellular voids found in the artificial leather fiber sheet of the present invention are formed without using any foaming agent, and have a structure not found in conventional nonwoven structures. The cell-shaped void portion is formed by impregnating the fiber assembly containing the wet-heat-adhesive crimped fiber with water, and
Heat treatment at 0 ° C., that is, the boiling temperature of water, a number of bubbles are generated in the fiber aggregate, the fibers of the aggregate move due to the bubble pressure, and the generated space becomes a cellular void in the fiber aggregate, and at the same time, The heat and heat adhesive crimped fibers are fused together,
The inner wall surface of the void portion is fixed, and the fibers of the other portions are bonded to each other to form an entangled structure. Of course, the use of known adhesives and foaming agents for secondary purposes is not a problem.

The fiber assembly has the feature that no organic solvent or foaming resin is required to form the cellular voids. Therefore, the load and burden on the environment and workers are extremely small, and the manufacturing cost can be reduced. This advantage is a great effect in practical use. The heating of the hydrated fiber assembly is performed by blowing steam or using high-frequency electromagnetic waves such as 2450.
It can be heated by microwaves of MHz. High-period electromagnetic wave heating is preferred because bubbles are easily generated in the fiber layer.

After the wet-heat-adhesive crimped fibers are fused, the fiber assembly is cooled by a known method to fix the structure of the porous fiber assembly. Since the fiber assembly after the wet heat treatment contains hot water, it is preferably immersed in cold water or cooled with a cold water shower, and cooling with cold air has low efficiency. If the fiber aggregate is compressed before cooling sufficiently, the cellular voids may be deformed. On the other hand, using the compression process,
It is also possible to adjust the cellular voids.

Next, the fiber sheet for artificial leather of the present invention will be described. The fiber sheet of the present invention is a fiber sheet for artificial leather made of the above-described porous fiber aggregate, and its basis weight is not particularly limited, but is preferably 100 to 600 g / m ² , more preferably 200 to 550 g / m ^2. It is. The thickness of the fiber sheet can be arbitrarily selected according to the use, and is not particularly limited, but is preferably 3 to 10 mm, more preferably 5 to 7 mm.

The fiber sheet of the present invention may be a composite in which a fiber layer (hereinafter, sometimes referred to as a porous fiber layer) composed of the aggregate and another layer are combined as necessary. Is possible.

Other forms of the layer include a fiber layer, a film, a sheet and a foamed layer. The fiber layer is a woven or knitted fabric, various nonwoven fabrics, or a net. The films, sheets and foams are molded with various resins, and the thickness and surface treatment include those optionally processed as needed. The other layer and the porous fiber layer can be connected by a mechanical entanglement method such as knitting, bonding, fusion, or needle punching.

When a fiber sheet is used as the other layer, it is preferable to use a woven or knitted fabric or a non-woven fabric, and it is more preferable to use a nap-woven or knitted fabric or a nap-woven nonwoven fabric from the viewpoint of flexibility and feeling. The knitted woolen knitted fabric may be processed into a fluff through a napping process, in addition to the napped yarn systematically erected from another layer.

The artificial leather made of the fiber sheet for artificial leather of the present invention has a long diameter of 0.5 to 2 mm on at least a part of the surface.
Is characterized in that 5 to 30 openings / cm ² exist. The opening is formed in a hole shape on the fiber sheet surface from the surface toward the inside, and is a substantially circular hole.
The artificial leather obtained by the present invention is what is called a suede-like artificial leather.

Further, by providing a grain surface layer on the fiber sheet for artificial leather of the present invention, artificial leather with silver can be obtained. Examples of the polymer constituting the silver layer include a polyurethane elastomer and an acrylic elastic binder.

In the present invention, by forming a fiber-fused dense layer on the porous fiber layer of the present invention as a silver surface layer, the surface can be made smooth and air permeability can be further provided. As a method of forming a fiber-fused dense layer on the surface of the fiber layer, the surface of the fiber layer after the above-mentioned wet heat treatment is heated and pressurized by a normal method, whereby the wet-heat-adhesive crimped fiber of the surface layer is melted, Re-solidification forms a dense layer with a smooth surface. As a continuous hot-pressing method, for example, a method of contact heating with a 180 ° C. heat roller is preferable.

When the cross section of the obtained fiber sheet is observed with a scanning electron microscope, the dense layer has a network structure in which the wet-heat-adhesive crimped fibers are irregularly entangled and fused to form a network structure. It has a thickness of 100 μm to about 300 μm and has a large number of fine through holes. The thickness of the dense layer and the pore size of the fine pores vary depending on the type and content of the adhesive fiber and the thermocompression bonding conditions. The surface of the dense layer is smooth and has air permeability.

Next, a method for producing the fiber sheet for artificial leather of the present invention will be described. As an example of the production method, a method using a napped nonwoven fabric is exemplified. A staple fiber composed of 100% by mass of split-type wet-heat-adhesive crimped fiber is subjected to card treatment and needling treatment in a conventional manner to be extremely fine, and the single fiber fineness is reduced. After setting to 0.33 dtex, a napped nonwoven fabric is obtained through a napped step and a shirring step. The obtained napped nonwoven fabric was immersed in water, irradiated with microwaves, and heated while generating air bubbles from the interior of the napped nonwoven fabric, whereby cellular voids were formed in the porous fiber layer, and openings were formed on the surface. A fiber sheet is obtained. Although this is a nonwoven fabric, there is no play hair, and the appearance is a fiber sheet suitable as a suede-like fiber sheet. Further, by thermocompression-bonding the raised surface of the above-mentioned raised nonwoven fabric, a silver-finished suede having a smooth surface and elasticity can be obtained.

Hereinafter, the structure of the artificial leather fiber sheet of the present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic perspective sectional view of an example of the fiber sheet of the present invention. A porous fiber layer 2 is formed by the nap fibers 1 containing the wet-heat-adhesive crimped fibers, and the porous fiber layer 2 has cellular voids 3 surrounded by the nap fibers 1. In addition, an opening 4 is present on the surface of the sheet, and the opening is almost circular, whereas the cellular voids 3 present inside the porous fiber layer are irregular in shape. Many. The fiber sheet of the present invention can be called a suede-like fiber sheet.

FIG. 2 is a schematic perspective sectional view of another example of the fiber sheet of the present invention. On the surface of the porous fiber layer 2, there is provided a silver surface layer 5 composed of a fiber-fused dense layer. In the fiber-fused dense layer 5, there are penetrating fine holes 6 formed by deforming the wet-heat-adhesive crimped fibers by thermocompression bonding. The fiber sheet shown in FIG. 2 can be called a grain-like fiber sheet.

The fiber sheet for artificial leather according to the present invention is used for shoes,
It can be used for various applications such as bags, belts, accessories, furniture upholstery, coats, and automobile interior fabrics.

[0033]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, each physical property in an Example was calculated | required by the following method. (1) Size of Cellular Void The major axis of the void was measured using a caliper. The depth of the gap was measured by piercing the hole with a needle graduated in units of 0.2 mm and visually measuring the length from the bottom to the surface. (2) Crimping rate After winding the yarn with a scalpel remover until the scalp becomes 5500 dtex, a load of 10 g is hung at the center of the lower end of the scalpel,
This cassette was fixed on the upper part, and subjected to hot water treatment at 90 ° C. for 30 minutes under a load of 0.009 cN / dtex. Next, after leaving to dry at room temperature without load, a 10 g load is applied again and the yarn length after standing for 5 minutes is measured, and this is defined as L1 (mm). Next, a 1 kg load was applied, and the yarn length after standing for 30 seconds was measured.
m) was calculated by the following equation. Crimp rate (%) = {(L2-L1) / L2} × 100

Example 1 An ethylene-vinyl alcohol copolymer having an ethylene content of 44 mol% and MI = 10 and polyethylene terephthalate [intrinsic viscosity = 0.30 measured at 30 ° C. in a mixed solvent such as phenol / tetrachloroethane by weight]. 68], the ethylene-vinyl alcohol-based copolymer and polyethylene terephthalate are mixed in a single filament in a fiber cross section as shown in FIG. The composite polymer was spun at a spinning temperature of 260 ° C. so that the polymer had five layers and the polyethylene terephthalate had six layers. The obtained spun yarn is stretched using a normal roller plate type stretching machine so that the stretching ratio becomes 3 times, and 111 dtex /
A composite filament of 24 filaments was obtained. Using this fiber, the number of false twists is 2640 T / M, the single-stage heater temperature is 12
False twisting is performed at 0 ° C. and a two-stage heater temperature of 135 ° C. to separate and separate into an ethylene-vinyl alcohol copolymer and polyethylene terephthalate.
Was obtained. A cut pile yarn obtained by combining two of the above false twisted yarns into 222 dtex / 48 filaments, and a polyethylene terephthalate false twisted yarn (167)
dtex / 48 filaments) was used as ground yarn to knit a seal milling circular knitted fabric. The greige was split and shirred to prepare a pile shape to obtain an organized and processed cloth. The property value of the obtained organized and processed cloth is 2 mm in height of the cut pile, and the basis weight is 27.
It was 0 g / m ² . Next, the arranged cloth was immersed continuously in hot water of 98 ° C., then immersed in cold water, and dried at 130 ° C. On the surface of the obtained work cloth,
19 openings / cm ^{2 with a} major axis of 1 mm and a depth of 1 mm
A fibrous sheet which was present and had a suede-like appearance was obtained.

Example 2 Two false twisted yarns used in Example 1 were combined to form 334d
tex / 96 filament cut pile yarn and polyethylene terephthalate false twisted yarn (167 dtex)
/ 48 filaments) as a ground yarn to knit a seal milling circular knitted fabric. The greige was split and shirred to prepare a pile shape to obtain an organized and processed cloth. The property value of the obtained organized and processed cloth is a cut pile height of 5 mm and a basis weight of 540 g / m.
^{Was 2} . The surface of the arranged cloth is pressed at a temperature of 180 °
Thermocompression bonding was performed using a calender roll having a roll temperature of 5 kg / cm and a roll temperature of 5 ° C. The obtained fiber sheet had a dense layer having a smooth surface, and a fiber layer having penetrating micropores was formed adjacent to the lower surface thereof. This could be used as a suede-like fiber sheet with silver.

[0036]

According to the present invention, a suede-like and silver-toned artificial leather fiber sheet can be obtained under aqueous processing conditions.

[Brief description of the drawings]

FIG. 1 is a schematic perspective sectional view showing an example of a fiber sheet of the present invention.

FIG. 2 is a schematic perspective sectional view showing another example of the fiber sheet of the present invention.

FIG. 3 is a cross-sectional view of an example of the split peelable composite filament used in the present invention.

[Explanation of symbols]

 1: Napped fiber 2: Porous fiber layer 3: Cellular void portion 4: Opening portion 5: Fiber-fused dense layer 6: Penetrating fine hole 7: Ethylene-vinyl alcohol copolymer 8: Polyethylene terephthalate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D06N 3/18 D03D 1/00 Z 4L048 // D03D 1/00 15/00 G 15/00 D04B 21/00 B D04B 21/00 D06M 17/00 BJ F-term (reference) 4F055 AA02 AA03 BA02 BA11 DA07 DA10 EA04 EA07 EA13 EA15 EA17 EA22 EA24 EA27 GA34 GA35 HA12 4L002 AA05 AA07 AB04 AB05 AC00 AC05 AC07 BA00 BB AB03 AB04 AC01 BD01 DA01 4L036 MA04 MA05 PA01 PA03 PA05 PA19 RA04 RA10 4L041 AA07 BA04 BA05 BA09 BA34 BA48 BD15 CA06 CA44 DD01 DD06 DD11 EE12 4L048 AA18 AA21 AA30 AA35 AA44 AB09 AB21 AC18 BC03 CA11 CA18

Claims (7)

[Claims] 1. A porous fiber aggregate comprising fibers having a single fiber fineness of 3.3 dtex or less containing 10 to 100% by mass of wet-heat-adhesive crimped fibers, wherein a large number of cells are provided inside the aggregate. A fiber sheet for artificial leather comprising a porous fiber assembly having a void-like portion and at least a part of the fibers constituting the assembly being heat-bonded by wet-heat-adhesive crimped fibers. 2. A fiber sheet for artificial leather comprising the porous fiber aggregate according to claim 1 and another layer, wherein the porous fiber aggregate is present on at least one surface thereof. 3. The crimp according to claim 1, wherein the crimp is a three-dimensional crimp.
2. The fiber sheet for artificial leather according to item 1. 4. The fiber sheet for artificial leather according to any one of claims 1 to 3, wherein the fiber is a fiber in which an ethylene-vinyl alcohol copolymer is present on at least a part of the surface of the wet-heat-adhesive crimped fiber. . 5. An opening having a major axis of 0.5 to 2 mm in at least a part of the surface of the fiber sheet according to claim 1.
Artificial leather with 30 pieces / cm ² . 6. An artificial leather having a grain surface layer on at least one surface of the fiber sheet according to claim 1. 7. The artificial leather according to claim 6, wherein the silver surface layer is a dense layer made of a porous fiber aggregate.