JPH0860556A - Artificial leather and its production - Google Patents

Abstract

PURPOSE: To obtain a high-quality artificial leather excellent in balance of elongation, hardly causing deformation of a product in processing, further, excellent also in durability (resistance to hydrolysis) and to provide a method for producing the artificial leather. CONSTITUTION: This artificial leather is obtained by impregnating and/or coating a nonwoven fabric with a solution of a polyurethane resin, carrying out wet coagulation of the polyurethane resin and subjecting the treated nonwoven fabric to surface finishing and the nonwoven fabric is obtained by subjecting a divided type conjugate fiber web obtained by combining different fibers or a web obtained by blending the divided type conjugate fiber web with a non- dividing type fiber to spun lace finishing, and the polyurethane resin is a polyurethane resin consisting essentially of a polyester-based polyurethane resin. A fluorine-containing polyurethane resin in an amount of 0.1-3.0 pts. wt. based on 100 pts.wt. of the polyester-based polyurethane resin is blended as the polyester-based polyurethane resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial leather and a method for producing the same, and more specifically, it has excellent balance of elongation, less deformation of the product when processed into a product, and further excellent durability. The present invention relates to high quality artificial leather and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, various kinds of artificial leather have been proposed. Typical examples thereof are: (1) Mechanical island punching of sea-island type composite fiber into a fiber entangled body, Artificial leather that has been subjected to surface finishing by impregnating and applying a polyurethane resin to a non-woven fabric made of ultrafine fibers with a structure that approximates the fibrils of collagen fibers of natural leather. (2) Artificial leather obtained by impregnating and applying a polyurethane resin to a fiber entangled body made of ultrafine fibers obtained by mechanically needle-punching sea-island type composite fibers, removing sea components, and subjecting to surface finishing. (3) After mechanically needle-punching the heat-shrinkable fiber or the fiber assembly in which the heat-shrinkable fiber is partially blended,
Artificial leather made by impregnating and applying a polyurethane resin to a nonwoven fabric that has been densified by heat shrinking to make it densified, and then surface finishing. (4) The split type conjugate fiber was mechanically needle punched to form a fiber entangled body, and the nonwoven fabric that was split and processed by chemical treatment with a solvent, acid, alkali, etc. was impregnated with polyurethane resin, and was surface-finished. Artificial leather. (5) An artificial leather in which a fiber entangled body obtained by mechanically needle-punching splittable conjugate fibers is impregnated with polyurethane resin, applied, and then splitted by a chemical treatment with a solvent, acid, alkali or the like, and surface-finished. and so on.

[0003]

However, in the above-mentioned artificial leather, since all the non-woven fabrics are obtained by mechanical needle punching, the entanglement density cannot be sufficiently increased, and the mechanical leather cannot be mechanically punched. When the needle punching process is performed, the machine flow direction and the direction of the fibers perpendicular to the machine flow direction (width direction) are not evenly arranged, and as a result, artificial leather that is easily stretched in the width direction and hard to stretch in the machine flow direction is obtained. It was
The above tendency is due to heat shrinkage treatment like (3),
Even if ultrafine fibers were used as in (1) and (2), it could not be resolved. Also, it is easy to stretch in the width direction,
Artificial leather that is difficult to stretch in the machine direction, that is, a product obtained by processing artificial leather that has a poor elongation balance has a problem that the shape retention is poor and the shape tends to collapse.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a specific nonwoven fabric, and have completed the present invention.

[0005]

The artificial leather of the present invention is an artificial leather obtained by impregnating and / or applying a polyurethane resin solution to a non-woven fabric, wet coagulating the polyurethane resin, and finishing the surface, The non-woven fabric is a non-woven fabric obtained by spun-lacing a split-type composite fiber web combining different fibers or a split-type composite fiber web combining different fibers and a non-split-type fiber mixed cotton, and the polyurethane resin is polyester. It is characterized in that it is a polyurethane resin mainly composed of a system polyurethane resin.

The method for producing artificial leather according to the present invention is a hydroentangling method for a split type composite fiber web in which different fibers are combined or a web in which a non-split type fiber is mixed with a split type composite fiber web in which different fibers are combined. The step of simultaneously dividing and entanglement the fibers to obtain a non-woven fabric, the step of impregnating and / or applying a polyurethane resin solution consisting of a polyurethane resin mainly composed of polyester polyurethane resin, the step of wet coagulating the polyurethane resin, the polyurethane resin It is characterized by comprising a step of removing the solvent of the solution, a step of drying, and a step of finishing the surface.

The non-woven fabric used in the artificial leather of the present invention is
It is obtained by subjecting splittable conjugate fibers to spunlace processing. That is, nylon / polyester, nylon /
Splittable composite fiber webs made by combining different fibers such as polypropylene and nylon / polyethylene, or webs made by mixing non-splittable fibers with the splittable composite fiber webs described above, at the same time as entanglement of the fibers by high-pressure water flow. It is obtained by doing. Alternatively, the spunlace process may be performed after the mechanical needle punch process.

Nonwoven fabrics obtained by spunlacing the above-mentioned splittable composite fiber webs or webs obtained by mixing splittable composite fiber webs with non-splittable fibers have an apparent density of 0.20 to 0.28 g / cm ^3. A relatively high density one is suitable. If the density is too low, the elongation in the machine flow direction and the vertical direction becomes too large, the balance of the elongation of the artificial leather obtained by the tension during processing becomes unbalanced, and the obtained artificial leather lacks a sense of unity. May occur, and if the density is too high,
The resulting artificial leather may have poor stretchability, or the nonwoven fabric may not be sufficiently impregnated with the polyurethane resin, which may cause a problem that the resulting artificial leather has poor mechanical properties such as peel strength and tear strength. There is.

Further, a non-woven fabric obtained by spunlacing a split type composite fiber web of different fibers or a split type composite fiber web of different types of fibers mixed with non-split type fibers is Elongation in the machine flow direction during manufacture of artificial leather (X), and elongation in the direction perpendicular to the machine flow direction during manufacture of artificial leather (Y)
Preferably satisfies the condition shown in Formula 1.

[Equation 1]

The weight of the nonwoven fabric obtained by spunlacing a splittable conjugate fiber web or a web obtained by blending a splittable conjugate fiber web with non-splittable fibers is appropriately selected depending on the intended use of the artificial leather product. For example, when artificial leather is used as a material for shoes and bags, 200
A non-woven fabric of about 400 g / m ² is used.

The non-woven fabric used in the artificial leather of the present invention is
For the purpose of improving the texture of the product artificial leather, attach Povar (polyvinyl alcohol) or silicone,
It may be one in which the mutual adhesive force between the fiber and the binder to be processed later is weakened. At this time, the amount of Poval, silicone, or a mixture thereof, attached is about 1 to 15% by weight with respect to the web fiber. Also,
The non-woven fabric used for the artificial leather of the present invention may be subjected to surface smoothing for the purpose of improving the surface smoothness of the non-woven fabric.

The polyester-based polyurethane resin used in the present invention is obtained by reacting a polyester-based polyol component, an isocyanate component, and a low-molecular chain extender added as necessary. Specific examples of the polyester-based polyol component include polyethylene adipate, polybutylene adipate, poly-ε-caprolactone, and the like, and specific examples of the isocyanate component include 2,4-tolylene diisocyanate, 2,
6-Tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and the like can be mentioned. Specific examples of the low molecular chain extender include aliphatic diols, alicyclic diols, alicyclic diamines, and hydrazine derivatives.

The above-mentioned polyester-based polyurethane resin has excellent coagulability when impregnated into a non-woven fabric, coated and wet-coagulated and has excellent workability, but has poor durability (hydrolysis resistance) and hydrolysis. Depending on the product, the polyurethane resin layer on the surface of the artificial leather and the non-woven fabric can be easily peeled off,
The surface may be cracked. On the other hand, polyether polyurethane resin and polyether / polyester polyurethane resin (hereinafter simply referred to as “polyether polyurethane resin”) have excellent hydrolysis resistance, but wet coagulation after impregnation and application of polyurethane resin. It is inferior in coagulability at the time of making it, and therefore is remarkably inferior in workability during production.
Therefore, in order to improve the hydrolysis resistance, it is desirable to mix and use the fluorine-containing polyurethane resin with the polyester polyurethane resin.

The fluorinated polyurethane resin is obtained by addition-reacting a urethane prepolymer having an isocyanate group at its terminal with a perfluoroalkyl group-containing compound having an active hydrogen group.

The urethane prepolymer is a polyester polyol such as polyethylene adipate, polybutylene adipate or poly-ε-caprolactone; a polyol component such as polyether polyol such as polyethylene glycol, polypropylene glycol or polytetramethylene glycol; -Tolylene diisocyanate, 2,6-Tolylene diisocyanate, 4,4'-
It can be obtained by reacting an isocyanate component such as diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate.

Specific examples of the perfluoroalkyl group-containing compound having an active hydrogen group which undergoes an addition reaction with the urethane prepolymer include those represented by the general formulas (A) to (E) in Chemical formula 1. .

Embedded image (However, R _f represents a perfluoroalkyl group, and R represents an alkyl group.)

Among the compounds represented by the above general formula, the perfluoroalkyl group having 6 to 18 carbon atoms is particularly preferable. Further, the fluorine content in the fluorinated polyurethane resin is preferably 12 to 35% by weight, and therefore, it is desirable to select and use the molecular weights and types of the urethane prepolymer and the perfluoroalkyl group-containing compound.

The amount of the fluorine-containing polyurethane resin compounded is 0.1 to 3.0 parts by weight, more preferably 0.2 to 2.0 parts by weight, based on 100 parts by weight of the polyester polyurethane resin.
Parts by weight. If the blending amount of the fluorinated polyurethane resin is too small, the durability cannot be sufficiently improved, and if the blending amount of the fluorinated polyurethane resin is too large, the workability deteriorates, and the peel strength of the artificial leather to be obtained, etc. There is a problem in that the physical properties of the product are deteriorated, workability such as adhesion processing is deteriorated, and the cost is increased. The preferred fluorine content in the total polyurethane resin is 0.02 to 1.6% by weight, and more preferably 0.07 to 1.0% by weight in the total polyurethane resin.

The above polyester-based polyurethane resin may be combined with a resin other than the polyester-based polyurethane resin, such as a polyether-based polyurethane resin, a polycarbonate-based polyurethane resin, or a resin other than the polyurethane resin, as long as the above-mentioned characteristics are not impaired. Even a copolymer resin or a mixture can be used. Further, the polyurethane resin composition mainly composed of the above polyester-based polyurethane resin, if necessary, an antioxidant,
UV absorbers, pigments, dyes, surfactants, antistatic agents,
It is also possible to add various additives such as flame retardants, anti-adhesive agents, fillers, cross-linking agents and collagen powder.

Next, a method for manufacturing the artificial leather of the present invention will be described.

The non-woven fabric used in the artificial leather of the present invention is
Nylon / polyester, nylon / polypropylene,
A split-type composite fiber web combining different fibers such as nylon / polyethylene, or a web obtained by mixing the above-mentioned split-type composite fiber web with non-split-type fibers is spun laced, that is, at the same time the fibers are entangled by a high-pressure water stream. It is obtained by dividing the fibers. The nonwoven fabric obtained as described above may be treated with Poval (polyvinyl alcohol), silicone, a mixture thereof, or the like, if necessary, or may be surface-smoothed. Furthermore, the above nonwoven fabric may be mechanically needle punched before being spun laced.

Next, the non-woven fabric obtained as described above is impregnated with a polyurethane resin solution mainly composed of a polyester-based polyurethane resin and applied, and then water or
It is dipped in a non-solvent such as an aqueous solution of a solvent such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone or dimethylsulfoxide to wet-coagulate the applied polyurethane resin and remove the solvent of the polyurethane resin solution. The non-solvent used at this time is 0 to
A 20% aqueous dimethylformamide solution is particularly preferred.

Further, after washing with water and drying, a polyurethane resin solution, a polyamide resin solution, an acrylic resin solution, a polyamino acid resin solution, or a mixed solution of these resins can be prepared by a conventional gravure roll coater or the like. Surface finishing is performed by means of applying a surface treatment agent, transferring means of a skin layer obtained by applying a polyurethane resin solution on release paper, or the like to obtain the artificial leather of the present invention.

Furthermore, the above-mentioned artificial leather may be subjected to processing such as embossing or rubbing which is applied to conventional artificial leather.

[0025]

The artificial leather of the present invention is obtained by spunlacing a split type composite fiber web in which different fibers are combined as a nonwoven fabric or a split type composite fiber web in which different fibers are combined and non-split type fibers are mixed. Since it uses a non-woven fabric, it has an excellent balance of elongation, and when processed into products such as shoes and bags, it has excellent shape retention and does not lose its shape.

[0026]

The present invention will be described in more detail with reference to specific examples, but the present invention is not limited to the examples shown below.

Example 1 The web shown in Table 1 was needle punched and then spun laced to obtain a nonwoven fabric.

[Table 1] Split fiber: Nylon / polyester (ratio 50/50) Fineness: 1.0 denier (after splitting) Fiber length: 30-40 mm Weight:・ 250 g / m ² Apparent density ・ ・ ・ 0.25 g / cm ³ Elongation balance ・ ・ 1.1 ^{* 1} * 1 Elongation in the direction perpendicular to the machine flow direction during artificial leather production / During artificial leather production Elongation in machine direction

The obtained non-woven fabric was dipped in a treatment liquid having the composition shown in Table 2, squeezed at a squeezing ratio of 100%, dried in a heat-circulation oven at 100 to 130 ° C. for 5 minutes, and then 180 A roll heated to ℃ was pressed and pressed for 2 minutes for surface smoothing.

[Table 2] Water 100 parts by weight Silicone ^{* 2} 2 parts by weight Poval ^{* 3} 2 parts by weight * 2 Geranex SH: Matsumoto Yushi Co., Ltd. * 3 Gohsenol: Nippon Gosei Co., Ltd.

A surface-smoothed non-woven fabric was impregnated with a polyurethane resin solution shown in Table 3 (Basis weight: 700 g / m ² ).
After that, the polyurethane resin shown in Table 4 was uniformly applied (Basis weight: 900 g / m ² ).

[Table 3] Polyester polyurethane resin ^{* 4} 100 parts by weight Fluorine-containing urethane resin ^{* 5} 1 part by weight Anionic surfactant 0.5 parts by weight Nonionic surfactant 4 parts by weight Silicone foam stabilizer 0.5 parts by weight Pigment 10 parts by weight Dimethylformamide 125 parts by weight * 4 Resamine CU4310 (solid content 30%): Dainichiseika * 5 Crisbon FX3D (solid content 60%, fluorine content in solid content 17%): Dainippon Ink and Chemicals

[Table 4] Polyester polyurethane resin ^{* 4} 100 parts by weight Fluorine-containing urethane resin ^{* 5} 1 part by weight Anionic surfactant 0.5 parts by weight Nonionic surfactant 4 parts by weight Silicone foam stabilizer 1 part by weight Pigment 10 Parts by weight Dimethylformamide 52 parts by weight * 4 Resamine CU4310 (solid content 30%): Dainichi Seika Co., Ltd. * 5 Solid content 60%: Dainippon Ink and Chemicals, Inc.

After the polyurethane resin was uniformly applied, the polyurethane resin was wet-coagulated in a 10% aqueous solution of dimethylformamide, washed with warm water at 50 ° C. and desolvated, and then hot air circulation type at 100 to 130 ° C. It was dried in an oven for 5 minutes. Further, the polyurethane resin surface treatment agent shown in Table 5 was applied four times with an 80 mesh gravure roll and embossed with an embossing roll at 150 ° C. to obtain artificial leather. The artificial leather obtained is
It had a sense of unity, had a moderate waist and soft texture, and had an elongation balance of 1.1, which was also excellent in terms of elongation balance.

[Table 5] Polyurethane surface treatment agent 100 parts by weight Thinner 140 parts by weight Pigment 180 parts by weight

Example 2 An artificial leather was obtained in the same manner as in Example 1 except that the web shown in Table 6 of the nonwoven fabric was needle punched and then spun laced. The obtained artificial leather has a feeling of unity, has an appropriate waist and soft texture, and has an elongation balance of 1.0,
It also had a good balance of elongation.

[Table 6] Split fiber: Nylon / polyester (ratio 50/50) Fineness: 0.2 denier (after split) Fiber length: 30-40 mm Weight:・ 250 g / m ² Apparent density ・ ・ ・ 0.25 g / cm ³ Elongation balance ・ ・ 0.9 ^{* 1} * 1 Elongation in the direction perpendicular to the machine flow direction during artificial leather production / During artificial leather production Elongation in machine direction

Example 3 An artificial leather was obtained in the same manner as in Example 1 except that the web shown in Table 7 of the non-woven fabric was needle punched and then spun laced. The obtained artificial leather has a sense of unity, has a proper waist and soft texture, and has an elongation balance of 1.2.
It also had a good balance of elongation.

[Table 7] Split fiber: Nylon / polyester (ratio 50/50) Fineness: 1.0 denier (after splitting) Fiber length: 30-40 mm Weight:・ 200g / m ² Apparent density ・ ・ ・ 0.23g / cm ³ Elongation balance ・ ・ 1.1 ^{* 1} * 1 Elongation in the direction perpendicular to the machine flow direction during artificial leather production / During artificial leather production Elongation in machine direction

[Example 4] An artificial leather was obtained in the same manner as in Example 1 except that the fluorine-containing urethane resin was not added.
The obtained artificial leather had a feeling of unity, had an appropriate waist and soft texture, and had an elongation balance of 1.1, which was also excellent in elongation balance.

Comparative Example 1 An artificial leather was obtained in the same manner as in Example 1 except that the web shown in Table 8 was replaced by the one obtained by needle punching. The obtained artificial leather had an elongation balance of 1.5, which was poor in elongation balance, and the product obtained was prone to lose its shape when used in a shoe cover or the like.

[Table 8] Fiber: Polyester / nylon (ratio 80/20) Fineness: 2.0 denier Fiber length: 30-40 mm Weight: 250 g / m ² Apparent density ・ ・ ・ 0.18 g / cm ³ Elongation balance ・ ・ 1.4 ^{* 1} * 1 Elongation in the direction perpendicular to the machine flow direction during artificial leather production / machine flow direction during artificial leather production Growth of

[Comparative Example 2] Polyurethane resin is a polyether / polyester polyurethane resin (Resamine CU
7420NL; manufactured by Dainichiseika Co., Ltd.)
An artificial leather was obtained in the same manner as in. The obtained artificial leather had a sense of unity, had a proper waist and soft texture, and had an elongation balance of 1.1, which was also excellent in elongation balance, but the coagulability during wet coagulation was poor, It was inferior in workability.

The artificial leathers obtained in Examples 1 and 4 and Comparative Example 2 were left under conditions of 70 ° C. and 95% humidity, and immediately after production, 1 week, 2 weeks, 3 weeks, 4 After 5 weeks, the peel strength after 5 weeks was measured by the following method, and the retention rate of the peel strength was obtained by the calculation shown in Formula 2. The results are shown in Table 9
Shown in

[Equation 2]

[Measurement Method] A cloth tape (width: 2 cm) coated with a heat-sensitive adhesive on one side was applied to the sample surface with the adhesive-coated side, and pressure-bonded with an iron (temperature 120 ° C.), and then the tape end. The sample and the sample end are attached to a Shopper type tester, and the peel strength when the tape and the sample are peeled off is measured.

[0038]

[Table 9]

[0039]

EFFECT OF THE INVENTION The artificial leather of the present invention has a good balance of elongation and excellent shape retention when processed into products such as shoes and bags.
A product that is hard to lose its shape can be obtained. Further, the artificial leather of the present invention has excellent workability during processing, and therefore can be produced in a short time, and it is possible to provide an artificial leather of excellent quality at low cost.

Further, as is clear from the results shown in Table 9,
By using a polyurethane resin containing a specific amount of a fluorine-containing polyurethane resin in the artificial leather of the present invention, the durability (hydrolysis resistance) is improved and it has the same durability as when a polyether polyurethane resin is used. An artificial leather can be obtained, and therefore, there is little possibility that the polyurethane resin layer and the non-woven fabric are separated during use, or that the artificial leather surface is cracked.

Claims (5)

[Claims] 1. An artificial leather obtained by impregnating and / or applying a polyurethane resin solution to a non-woven fabric, wet-coagulating the polyurethane resin, and then finishing the surface, wherein the non-woven fabric is a split type in which different fibers are combined. A non-woven fabric obtained by spun-lacing a composite fiber web or a split type composite fiber web in which different fibers are mixed with non-split type fibers, and the polyurethane resin is a polyurethane resin whose main component is a polyester-based polyurethane resin. Artificial leather that is. 2. The polyurethane resin mainly comprising a polyester polyurethane resin is a polyurethane resin in which 0.1 to 3.0 parts by weight of a fluorine-containing polyurethane resin is mixed with 100 parts by weight of a polyester polyurethane resin. Artificial leather. 3. The artificial leather according to claim 2, wherein the fluorine content in the fluorine-containing polyurethane resin is 12 to 35% by weight. 4. Manufacture of artificial leather of a nonwoven fabric obtained by spunlacing a splittable composite fiber web combining different fibers or a web obtained by mixing non-splitting fibers into a split composite fiber web combining different fibers. The artificial machine according to claim 1 or 2, wherein the elongation (X) in the machine flow direction at the time and the elongation (Y) in the direction perpendicular to the machine flow direction at the time of manufacturing the artificial leather satisfy the condition shown in Formula 1. leather. [Equation 1] 5. A non-woven fabric in which fibers are split and entangled at the same time by a hydroentangling method using a split-type composite fiber web in which different fibers are combined or a web in which non-split-type fibers are mixed with a split-type composite fiber web in which different fibers are combined. , A step of impregnating and / or applying a polyurethane resin solution consisting of a polyurethane resin mainly composed of a polyester-based polyurethane resin to the nonwoven fabric, a step of wet coagulating the polyurethane resin, a step of removing the solvent of the polyurethane resin solution, and a drying step. Process, surface finishing process,
A method for producing artificial leather, which comprises: