JP2000248472A - Abrasion-resistant leather-like sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leather-like sheet that has excellent abrasion resistance, scratch resistance, excoriation resistance, and crease resistance and gives good fabric hand. SOLUTION: This leather-like sheet comprises fiber assembly impregnated with a polyurethane resin and a resin coating layer formed on the surface of the assembly. The resin-coating layer comprises a silicone-modified polyurethane resin that is crosslinked with a polyisocyanate curing agent and the resin- coating layer is bonded to the fiber assembly with an adhesive of an noncrosslinkable resin mainly comprising polyurethane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leather-like sheet which is excellent in abrasion resistance, scratch resistance, abrasion resistance and fold wrinkles and has a good texture.

[0002]

2. Description of the Related Art Conventionally, various leather-like sheets having high surface strength have been proposed. For example, in a leather-like sheet in which a coat layer made of an elastic polymer is laminated on a base layer, a leather-like sheet in which the outermost surface of the coat layer is formed of urethane containing fine particles having a Brinell hardness of 20 to 100 is used. Are known. Further, in a leather-like sheet obtained by laminating a coat layer of an elastic polymer on a base layer, a leather-like sheet in which the outermost surface of the coat layer is formed of a one-component urethane having a 100% modulus of 150 kg / cm ² or more, or A leather-like sheet provided with a coating layer of an elastic polymer on a base layer, wherein the outermost surface of the coating layer is a silicon-modified urethane layer, and the leather-like sheet is formed for the purpose of improving scratch resistance by sliding the surface. Etc. are also known.

[0003]

However, among the conventionally proposed methods, Brinell hardness of 20 to 10 is used.
When a polyurethane containing fine particles having a particle diameter of 0 is used, there is a disadvantage that the glossiness is easily adversely affected, and with respect to the scratch resistance, when exposed to the surface, the scratch is rather accelerated. Further, the outermost surface of the coat layer is 100
In the case of a leather-like sheet forming a one-component urethane layer of 150 kg / cm ² or more at a% modulus, the scratch resistance is considerably improved, but almost no effect is recognized on instantaneous abrasion and the texture is hard. Has disadvantages. Similarly, when silicon-modified urethane was applied to the outermost surface layer, it could not be an effective means against instantaneous abrasions. The present inventors have conducted intensive studies in order to eliminate the above-mentioned conventional disadvantages, and as a result, found a leather-like sheet having excellent abrasion resistance, scratch resistance, abrasion resistance and fold wrinkles on the outermost surface, and a good texture, The present invention has been reached.

[0004]

That is, the present invention provides a leather-like sheet comprising a fiber assembly impregnated with an elastic polymer and a coating layer formed on the surface thereof, wherein the coating layer comprises a polyisocyanate-based curing agent. A leather-like sheet comprising a silicone-modified polyurethane resin cross-linked by, and wherein the coating layer is bonded to the fiber aggregate with an adhesive made of a resin mainly composed of a non-cross-linked polyurethane resin. is there. More preferably, the 100% modulus of the silicone-modified polyurethane resin of the coating layer is from 20 to
This is the case when it is within the range of 150 kg / cm ² . Further, a leather-like sheet in which the amount of the polyisocyanate-based curing agent is 5 to 50% by weight based on the solid content of the silicone-modified polyurethane resin is preferable.

Hereinafter, the present invention will be described in detail. First, as the fibers constituting the fiber assembly which is the base layer of the present invention, ordinary fibers, for example, polyester, polyamide,
Examples include fibers made of synthetic resin such as polyacrylonitrile, polyolefin, and polyvinyl alcohol; chemical fibers such as regenerated cellulose; and natural fibers such as cotton, hemp, and wool. In the case of a synthetic fiber, not only a fiber composed of a single polymer but also a fiber obtained by mixing or spinning two or more kinds of polymers may be used. When mixed spun fibers or composite spun fibers are used, at least one polymer is extracted or decomposed and removed at any stage of producing a leather-like sheet from the composite polymers constituting the fibers. It is preferable to adopt a method in which the fibers are divided into polymer components constituting the fibers, or to convert the fibers into a bundle of ultrafine fibers or a porous fiber having a large number of hollows therein.

[0006] These fibers are made into a web and entangled by a needle punch or a high-speed fluid flow to form a nonwoven fabric. It can also be a knitted fabric. Further, a laminate of a nonwoven fabric and a knitted fabric can be used. These nonwoven fabrics, woven or knitted fabrics, and their laminated fabrics (hereinafter collectively referred to as fiber aggregates) are impregnated with a solution or dispersion of an elastic polymer. Prior to the impregnation treatment with the elastic polymer liquid, If necessary, the fiber aggregate is subjected to a surface smoothing treatment by a method such as hot pressing. Also, in order to prevent the morphological destruction of the fiber aggregate which is likely to occur during the subsequent impregnation and coagulation of the elastic polymer liquid and the extraction of the fiber constituent polymer, the surface of the fiber aggregate is heated and pressed to partially melt the constituent fibers. It is also possible to use a method of adhering or a method of impregnating and drying a fiber aggregate with a water-soluble resin typified by polyvinyl alcohol and gluing and fixing the fibers. The thickness of the fiber aggregate is 1.0 to
3.0 mm is preferred.

The elastic polymer impregnated in the fiber assembly of the present invention is selected from the group of elastic polymers such as polyurethane, acrylic polymer, acrylonitrile-butadiene copolymer and styrene-butadiene copolymer. At least one type of elastic polymer can be used. Polyurethane is particularly preferred from the viewpoint of the feeling and the adhesive strength with the durable surface layer. Polyurethane has a number average molecular weight of 50
0 to 2500 polymer diols such as polyester diols, polyether diols, polyester ether diols, polycaprolactone diols, at least one diol selected from polycarbonate diols and the like, and an organic polyisocyanate such as an aromatic diisocyanate; At least one organic polyisocyanate selected from the group consisting of an aromatic triisocyanate, an alicyclic diisocyanate, an aliphatic diisocyanate having a cyclic group, triphenylmethane-4,4,4-triisocyanate, and an active hydrogen atom At least 2
It is a polyurethane elastomer obtained by reacting a low molecular compound having a molecular weight of 300 or less, for example, a low molecular compound containing an active hydrogen atom such as a low molecular diol, a low molecular diamine, hydrazine or dicarboxylic dihydrazide as a chain extender.

The raw material composition of these polyurethanes can be appropriately selected from those satisfying various physical properties such as hand, deterioration resistance, yellowing resistance, dyeing property, etc., according to the intended application field of the leather-like sheet. . If necessary, other polymers, various stabilizers, coloring agents, coagulation regulators and the like are added to these elastic polymers. As described above, the elastic body is impregnated into the fiber aggregate in a state of a solution or a dispersion and solidified. As a coagulation method, a wet coagulation method is preferable in terms of texture. By using the wet coagulation method, the elastic resin becomes porous, and a natural leather-like texture can be obtained. The amount of the resin impregnated in the fiber assembly is 10 to 60 parts by weight based on 100 parts by weight of the fiber assembly in terms of solid content.

When the fiber aggregate is composed of a mixed spun fiber or a composite spun fiber composed of two or more kinds of polymers, the fiber is composed before or after the fiber aggregate is impregnated with the elastic resin. It is preferable to use a method in which at least one component of the polymer is dissolved or decomposed and removed to leave at least one component. For example, when the mixed spun fiber or the conjugate spun fiber is a fiber having a sea-island structure cross section, if the sea component polymer is dissolved or decomposed and removed, the island component polymer remains, and the fiber becomes an ultrafine fiber bundle, while the island component polymer is dissolved. When removed, the sea component remains and becomes a porous fiber having many hollow portions in the fiber. When the fiber is a composite spun fiber obtained by laminating a plurality of polymers in the length direction, a method in which the fiber is separated from the polymer by physical treatment or chemical treatment to make the fiber into an ultrafine fiber bundle. May be used.

After the fiber assembly is impregnated with the elastic resin, a coating layer made of the elastic resin is formed on the surface thereof. In the present invention, at least the surface side (the surface opposite to the adhesive surface) of the coating layer is made of a silicon-modified polyurethane resin crosslinked with a polyisocyanate-based curing agent. The type of the silicon-modified polyurethane resin constituting the surface layer of the coating layer is not particularly limited, and includes polyester, polyether, and polycarbonate. Systems are preferred. The silicone-modified polyurethane resin is a polyurethane modified by introducing a dimethylsiloxane unit into the main chain or side chain of the polyurethane. The degree of silicon modification is 5% in polyurethane.
Preferably, 50% by weight of dimethylsiloxane units are present. Especially one of silicone modified polyurethane resin
A resin having a 00% modulus of 10 to 150 kg / cm ² is preferred. 100% modulus is 10 kg / cm ²
If it is less than 3, the tackiness is very high and the surface strength is weak. The 100% modulus is 150 kg / cm ²
If the ratio exceeds 1, the surface layer becomes hard and the bending resistance becomes poor. Preferably it is 20 to 100 kg / cm ² . Examples of the polyisocyanate curing agent to be added to the silicon-modified polyurethane include an adduct of trimethylolpropane (TMP) and tolylene diisocyanate (TDI), and an adduct of TMP and 4,4'-methylenebis (cyclohexyl isocyanate) (HMDI) , T
Adduct of MP and hexamethylene diisocyanate (HDI), TMP and isophorone diisocyanate (IP
Organic polyisocyanates such as adducts of DI) and trimers of HMDI. As the organic polyisocyanate used in the present invention, two or more different organic polyisocyanates may be used in combination, and in particular, an aromatic or alicyclic polyisocyanate may be used in combination with an aromatic polyisocyanate. The addition amount is preferably 5 to 50% by weight based on the resin solid content of the silicone-modified polyurethane resin solution,
When the addition amount of the polyisocyanate curing agent is less than 5% by weight, the abrasion resistance and the abrasion resistance become poor, and
If the content exceeds% by weight, the flexibility is poor and the texture becomes hard. More preferably, it is in the range of 8 to 30% by weight. In addition, various additives such as an antioxidant, an ultraviolet absorber, a pigment, a dye, a surfactant, an antistatic agent, a flame retardant, a filler, a collagen powder, and the like are added as long as the reaction of the curing agent is not inhibited. You can also. By adding a polyisocyanate curing agent to the silicon-modified polyurethane resin solution, stretching the film, and heating to 40 to 130 ° C., the silicon-modified polyurethane is crosslinked. As mentioned above,
In the present invention, it is necessary that the surface side of the coating layer is formed of a silicon-modified polyurethane resin cross-linked by a polyisocyanate-based curing agent. Made of a modified silicone-modified polyurethane resin, and another elastic polymer layer may be present thereunder.

As the adhesive, a one-pack type, so-called non-crosslinked polyurethane resin is used. Examples of the type of the polyurethane resin constituting the adhesive include polyester-based, polyether-based, polycarbonate-based or blends or modified products thereof, and can be appropriately selected depending on the intended use field of the leather-like sheet. In particular, polyether-based polyurethane is preferable in terms of texture, deterioration resistance, yellowing resistance, cost, and the like. When the 100% modulus of the polyurethane resin as the adhesive is less than 5 kg / cm ² , the tackiness becomes extremely high, and the surface strength becomes weak. If it exceeds 50 kg / cm ² , the coating layer becomes too hard and the bending resistance becomes poor. Preferably 5-50k
g / cm ² . The adhesive is a one-component type polyurethane, that is, a non-crosslinked type polyurethane. When a two-component type crosslinked type polyurethane resin is used, it is not preferable in terms of texture and wrinkles.

The most preferable method for forming a coating layer is to apply a polyurethane resin for a coating layer on release paper, and then to dry the coated polyurethane resin solution. And then releasing the release paper after superimposing and integrating with the fiber aggregate. The thickness of the coating layer, particularly the thickness of the silicon-modified polyurethane resin layer crosslinked with a polyisocyanate-based curing agent, is preferably from 5 to 150 microns, more preferably from 10 to 100 microns in solid content. If it is less than 5 microns, the abrasion resistance will be poor, and if it exceeds 150 microns, the hand will be poor. The total thickness of the coating layer and the adhesive layer after drying is 20 to 200 microns, preferably 50 to 150 microns. As a coating method, it is coated on a release paper by means such as a knife coater, a comma coater, a roll coater, a reverse coater and the like. The 100% modulus is measured by the tensile strength at 100% elongation.

It is also possible to carry out embossing, kneading or relaxing as required.

The leather-like sheet obtained in the present invention has excellent abrasion resistance, scratch resistance, abrasion resistance and fold wrinkles, and furthermore has a good texture. These leather-like sheets are very suitable for applications such as balls, bags, bags, sports shoes and general shoes.

[0015]

EXAMPLES Next, the present invention will be described specifically with reference to Examples.
The present invention is not limited to these examples. In the examples, parts and percentages relate to weight unless otherwise specified.

Example 1 A sea-island composite fiber comprising 60 parts of 6-nylon (island component) and high-flow low-density polyethylene (sea component) was obtained by melt spinning, and this was 2.5-fold in 70 ° C warm water. It is stretched, applied with a fiber oil agent, dried by mechanical crimping, and cut into 51 mm to form 4-denier staples. A web with a basis weight of 500 g / m ² is formed by a cross lap method, and then alternately combined from both sides. Needle punching of about 500 punches / cm ² was performed, followed by heating at 120 ° C. and pressing with a calender roll to produce an entangled nonwoven fabric having a smooth surface. The basis weight of this entangled nonwoven fabric was 340 g / m ² , and the apparent specific gravity was 0.3. This entangled nonwoven fabric is mainly made of polytetramethylene ether-based polyurethane.
% Polyurethane dimethylformamide (DM
F) After impregnating the solution and dipping in a mixed solution of DMF / water = 15/85 to wet-solidify the polyurethane into a porous form,
The sea component in the conjugate fiber was eluted and removed in hot toluene to express ultrafine fibers (average fiber thickness of 0.001 denier) to obtain a fibrous sheet base layer. The obtained fibrous base material layer had a thickness of 1.0 mm and the amount of polyurethane was 120 g / m ² . On the other hand, release paper with grain (LINTEC TPR-8)
100 parts of silicone-modified polyether polyurethane (US-938, 100% modulus, 60%, solid content 30%) as a skin layer, and 5 parts of trimethylolpropane polyisocyanate curing agent (Nippon Seika N
E crosslinker solid content 80%), 30 parts of Resamine DUT4093 white (50% solid content manufactured by Dainichi Kasei), 30 parts of DMF, 30 parts of methyl ethyl ketone were applied on a dry base to a thickness of 50 microns, and then 100 C. for 5 minutes to obtain a skin layer. On top of this, a one-pack type polyether-based polyurethane (Resamine ME8133 manufactured by Dainichi Seika)
100 parts of a polyurethane resin solution of 20 parts of DMF and 20 parts of DMF are applied by wet so as to have a concentration of 100 g / m ² , and the above-mentioned fibrous sheet base layer is bonded thereto.
After drying at 0 ° C. for 2 minutes and then left at 40 ° C. for 1 day, the release paper was peeled off to obtain a leather-like sheet. Thereafter, in order to impart flexibility, the film was treated with a Wins dyeing machine at 90 ° C. for 1 hour, and dried at 110 ° C. for 3 minutes. The obtained leather-like sheet had good scratch resistance, fine folds and wrinkles, and had a soft texture. This was the best for sports shoes.

Example 2 50 parts of 6-nylon kneaded with a black pigment was dispersed in a
An entangled nonwoven fabric of multicomponent fibers containing 50 parts of polyethylene as a dispersion medium component was produced in the same manner as in Example 1. The basis weight was 450 g / m ² and the apparent specific gravity was 0.26. A 18% dimethylformamide (DMF) solution of a polyethylene adipate / polyethylene glycol copolymer-based polyurethane containing a black colorant is impregnated, and the same type of solution is applied to the surface thereof.
After knife coating with 0 g / m ² and wet coagulation in a 25% DMF aqueous solution, the polyethylene in the multicomponent fiber was dissolved and removed to obtain a fibrous sheet substrate layer composed of ultrafine fibers of 0.002 denier. The obtained fibrous sheet substrate layer has a basis weight of 5
The thickness was 1.3 mm at 00 g / m ² . The resin impregnation amount was 120 g / m ² . On the other hand, on a release paper (AR-121GS) made by Asahi Roll, 100 parts of a polycarbonate-based silicone-modified polyurethane resin Crisbon NY324 (manufactured by Dainippon Ink, 100% modulus 40 kg / cm ² , solid content 30%), DMF 30 parts, methyl ethyl ketone (MEK) 30 parts, pigment black 10 parts, polyisocyanate curing agent DN-950 (solid content 80 manufactured by Dainippon Ink and Chemicals, Inc.)
%) 10 parts by weight of a polyurethane resin solution was
It was applied so as to be 0 g / m ² . Then, the same resin NY324 (polycarbo-type silicon-modified polyurethane resin solid content 30%, manufactured by Dainippon Ink and Ink), which is the same as the skin layer, 100
Part, 10 parts of DMF, and 10% of MEK, a one-component polyurethane resin solution was applied by wet so as to have a weight of 120 g / m ² , and the above-mentioned fibrous sheet base layer was adhered to the solution.
After drying for 2 minutes at 40 ° C. and then standing at 40 ° C. for 1 day, the release paper was peeled off to obtain a leather-like sheet. The obtained leather-like sheet was excellent in abrasion resistance, good in wrinkles and texture, and was most suitable as a bag or a bag-like raw material.

Comparative Example 1 A leather-like sheet was obtained in the same manner as in Example 1 except that the polyisocyanate curing agent in the resin solution was not added to the skin layer of Example 1. When this was used as a raw material for sports shoes, this one had a sliding touch, but was inferior in scratch resistance and abrasion resistance, which was a problem.

Comparative Example 2 In Example 2, the adhesive layer was composed of 100 parts of a two-part polycarbonate urethane resin Chrisbon TA-205 (manufactured by Dainippon Ink, 50% solids) and a curing agent DN-950 (manufactured by Dainippon Ink) 15 parts of accelerator (accelerator T)
A leather-like sheet was obtained under exactly the same conditions as in Example 2 except that 3 parts of the polyurethane resin solution was applied so as to have a dry base of 50 μm. The obtained leather-like sheet had good scratch resistance and scratch resistance, but had poor folding and wrinkles and had a hard texture. When this was put in a bag, the target product could not be obtained.

Table 1 shows the evaluation results of the leather-like sheets obtained in Examples and Comparative Examples.

[0020]

[Table 1]

[0021]

The leather-like sheet obtained by the present invention has abrasion resistance,
The leather-like sheet is excellent in scratch resistance, scratch resistance, and wrinkles, and has a good texture. These leather-like sheets are very suitable for applications such as balls, bags, bags, sports shoes and general shoes.

Claims (2)

[Claims] 1. A leather-like sheet comprising a fiber assembly impregnated with an elastic polymer and a coating layer formed on the surface thereof, wherein the coating layer is made of a silicon-modified polyurethane resin crosslinked with a polyisocyanate-based curing agent. A leather-like sheet, wherein the coating layer is bonded to the fiber aggregate with an adhesive made of a resin mainly composed of a non-crosslinked polyurethane resin. 2. The silicone modified polyurethane resin constituting the coating layer has a 100% modulus of 20 to 150 kg /.
The leather-like sheet according to claim 1, which has a size of cm ² .