JPH03287879A - Leather-like sheet having back tone - Google Patents

Abstract

PURPOSE:To obtain a back-tone leather-like sheet having excellent surface characteristics by forming a fine irregular surface layer composed of collagen powder on a coating surface of a sheet composed of a substrate layer and a coating layer made of an elastic polymer and filling the recesses of the irregular surface with an oil and fat, etc. CONSTITUTION:A back-tone leather-like sheet exhibiting dry feeling similar to natural leather and deep color and having excellent compression strength, abrasion strength, scratch resistance, etc., of the surface can be produced by preparing a sheet material consisting of a substrate layer composed of e.g. a polyurethane elastomer and a fiber aggregate (e.g. nonwoven cloth composed of entangled fibers) and a polyurethane elastomer coating layer applied to one surface of the substrate layer, coating the surface of the sheet material with a liquid mixture of non-fibrous collagen powder having an average particle diameter of <=10mum and an apparent bulk density of 0.1-0.3g/cm<3> and a polymer composed mainly of a polyurethane, drying the coating layer, filling a liquid dispersion of an oil and fat and/or casein in the recesses of the irregular surface with a gravure roll, etc., and drying the product.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention has a Saran texture that feels like natural leather that absorbs sweat and has good sweat absorption properties.
It has a solid appearance and deep color similar to natural leather,
The present invention also relates to a nubuck-like leather-like sheet that looks matte and dark and has excellent surface strength.

<Conventional technology> Conventionally, nubuck-like leather-like sheets have been produced by forming ultrafine fibers on the surface and shaping them short by puffing them with sandpaper, or by using elastic polymers such as polyurethane. A method has been proposed in which a microporous coating layer is formed and the skin layer on the surface is ground away to expose a portion of the micropores.

However, all of these had an appearance similar to suede, which is natural leather, and were far from a nubuck-like appearance.

Many attempts have also been made to reproduce the appearance and texture of natural leather by mixing natural leather powder, collagen, etc. into the coating layer of a leather-like sheet. For example, Tokko Sho 63-2
3644, Japanese Patent Publication No. 63-315677, and the like. These leather-like sheets were merely mixed with large-sized leather powder, collagen powder, etc., and their surface condition was far from a nubuck-like appearance.

<Problems to be Solved by the Invention> The present invention has good sweat absorption properties, has the smooth texture of natural leather, has a smooth and natural touch similar to natural leather, and has a solid appearance and deep color. It provides a nubuck-like leather-like sheet with a matte and dark appearance and excellent surface strength.

Means for Solving the Problems> The present invention provides a leather-like sheet comprising a base layer containing a polymer mainly composed of an elastic polymer in a fiber aggregate and a coating layer composed of a polymer mainly composed of an elastic polymer. In this case, the surface of the coating layer is non-fibrous, the average particle size is 10μ or less, and the apparent bulk density is 0.
It has a finely uneven surface made of a mixture of 1 to 0.3 g/cm'' of collagen powder and a polymer mainly composed of polyurethane, and the recesses of the fine unevenness are filled with oil and/or casein. It is a nubuck-like leather-like sheet that is characterized by

That is, the present invention applies polyurethane to fiber aggregates such as woven fabrics, knitted fabrics, or fiber-entangled nonwoven fabrics made of any fibers such as ordinary fibers, ultrafine fibers and/or bundled fibers thereof, and special porous fibers. , acrylic polymers, acrylonitrile-butadiene copolymers, styrene-butadiene copolymers, and other synthetic leather rubbers. The base layer is made of a polymer mainly composed of an elastic polymer and a fiber aggregate, and one side of the base layer has a porous layer made of a polymer mainly composed of an elastic polymer such as polyurethane or plasticized polyvinyl chloride. A sheet-like product with a layer or a non-porous layer as a surface layer is formed, a polyurethane composition liquid containing collagen powder is applied to the surface and dried to form a sheet-like product, and oil and fat are applied to the surface of the sheet-like product. and/or an aqueous dispersion or solution of casein is applied and dried to produce a leather-like sheet.

The base layer of the present invention may be made of ordinary fibers, such as synthetic fibers such as polyester, polyamide, polyacrylonitrile, polyolefin, and polyvinyl alcohol, chemical fibers such as regenerated cellulose, natural fibers, or special fibers such as polyester, polyamide, etc. , needle punches and high-speed fluids made of ultrafine fibers such as polyacrylonitrile, or multicomponent fibers that can be transformed into ultrafine fiber bundles or special porous fibers by dissolving and removing at least the l component. One type of fabric selected from fiber-entangled non-woven fabrics, fiber-raised knitted fabrics, laminated fabrics of non-woven fabrics and knitted-woven fabrics, etc.
The multi-component fiber is made into an ultrafine fiber by impregnating the elastic polymer with an impregnating composition solution, and then applying a polymer coating composition solution as needed to coagulate it into a sponge structure in a non-solvent of the polymer. It is a sheet-like product that has been transformed into bundled fibers or special porous fibers, and is further coated with a polymer coating layer mainly composed of an elastic polymer, if necessary.

If ordinary fibers, especially those made of polyester or polyamide fibers, are used as the base layer, the leather-like sheet will have appropriate stiffness and excellent shape retention, while if one made of ultra-fine fiber bundles is used, When processed into shoes with a flexible texture, the top line will be sharp, and if you use special porous fibers, you will have a moderate waist and lightness, and the smooth texture of the surface and appearance will be improved. Combined with its solid feel and deep color, it creates an artificial leather product that is full of luxury.

Collagen used for the coating layer in the present invention includes animal skin,
Bone and keys are processed and purified using enzymes, etc., polymeric collagen fibers are extracted, cross-linked between the collagen fibers, and then crushed. Average particle size is 2 to 10μ, and apparent bulk density is 0.1. ~0.3 g/Cm3, preferably a non-fibrous collagen powder with a closest packed bulk density of 0.4 to 0.6 g/cm', such as CX240 and CX2 manufactured by Showa Denko.
60, etc. The average particle size of the collagen is 10
If it is larger than μ, the surface will feel rough and it will not be possible to obtain a smooth surface with fine grains, and it will not be possible to obtain the smooth and natural touch of natural leather. In addition, the apparent density is 0.3g
/Cm', the bulk of the collagen particles decreases, resulting in a decrease in affinity with resins, oils, and casein, resulting in lower coating film strength and less adsorption of oils, fats, and casein, resulting in a nubuck-like appearance. It is difficult to obtain a touch and durability is also reduced. Furthermore, the ability to absorb moisture and sweat is reduced, making it impossible to achieve the desired sweat absorbency. Moreover, when the apparent bulk density becomes smaller than 0.1 g/cm 3 , the strength of the collagen particles decreases and the strength of the coating film decreases. Therefore, in order to improve adhesion to the resin and obtain a smooth finished surface, it is preferable that the average particle size of collagen be 10 μm or less and the apparent bulk density be in the range of 0.1 to 0.3 g/cm 3 .

In the present invention, the apparent bulk density is JIS K 67.
21.

The weight ratio of the collagen powder to the polyurethane-based polymer is in the range of 1:1 to 2:1. If the amount of collagen powder is small, the sweat absorbing properties and smooth touch that are characteristic of collagen will not be obtained, and conversely, if the amount of collagen is too large, the collagen powder will not be sufficiently fixed by the polymer, resulting in a decrease in film strength. At the same time, the texture also deteriorates.

In the present invention, the polyurethane mixed with collagen powder is
At least one polymer diol having an average molecular weight of 500 to 2,500 selected from the group of polyester diols, polyether diols, polyester ether diols, polycaprolactone diols, polycarbonate diols, etc., and an organic polyincyanate, such as an aromatic at least one type of organic polyisocyanate selected from the group such as group diisocyanates, aromatic triisocyanates, alicyclic diisocyanates, aliphatic diisocyanates having a cyclic group, triphenylmethane 4.4', 4''-triisocyanates, etc. This is a polyurethane obtained by reacting a low-molecular compound having at least two active hydrogen atoms with a chain extender.

A polymer composition mainly composed of collagen and polyurethane is applied to a surface as a dispersion in which collagen is dispersed in a polymer solution. Depending on the purpose, coloring agents such as dyes and pigments, stabilizers, antistatic agents, and smoothing agents are added to the coating solution. The coating method is, for example, a roll coating method using a roll such as a roll with a fixed date or a smooth surface roll, a spray coating method, or a surface contact method. A preferred coating method is roll coating from the viewpoint of uniformity of coating.

The application amount is 5 to 50 g/r based on the weight of dry collagen.
n2, preferably in the range of 5 to 30 g/m''.

If the applied amount of collagen is less than 5 g/m'', the entire surface will not be covered with collagen powder, so the entire surface will not have a fine matte texture, and a saran touch will not be obtained. If the amount of coating is too large, the appearance will not deteriorate so much, but it will feel rough and the strength of the film will decrease, resulting in poor durability.

The surface coated with a polymer composition mainly composed of collagen and polyurethane has fine irregularities that are approximately the same size as the collagen particles, giving it a matte appearance. In the present invention, the fat and/or casein applied to the surface is adsorbed to the collagen particles and is filled into the concave portions of the fine irregularities on the surface. The leather-like sheet of the present invention is dyed before or after applying oil and/or casein to the finely uneven surface. It is preferable to dye the product before applying it, as this will give the color even more depth. The dyeing method is Wins dyeing method, Jigger dyeing method, etc. using metal complex dyes, acid dyes, disperse dyes, etc.

Examples of the oils and fats applied to the finely uneven surface in the present invention include:
A type of oil selected from hardening natural oils and fats such as castor oil, linseed oil, cottonseed oil, poppy oil, and tung oil, modified oils and fats thereof, and unsaturated higher fatty acids such as ricinoleic acid and cruic acid, and is usually prepared using an organic solvent. For example, it is applied by dissolving it in an organic solvent selected from the group of ethers, alcohols, ketones, esters such as ethyl acetate and butyl acetate, and hydrocarbons such as toluene, benzene, xylene, and thinner. Alternatively, it can be applied as an aqueous dispersion.

Further, casein is an amphoteric protein having an isoelectric point of pH 4.6, is present in milk as the main protein of dairy cows, and is a polymer mainly composed of amino acids with a molecular weight of 57,000 to 375,000. The casein is applied as an aqueous solution or an aqueous dispersion.

Fats and oils and casein may be used alone or in combination. When used in combination, they may be applied separately, but if the oil and fat dispersion is mixed with the casein solution or dispersion and then sprayed, the application and drying steps are only one time, which is economical. The coating amount is 1 to 10 g/l, preferably 2 to 5 g/l in terms of solid content, whether used alone or in combination, and the mixing ratio is appropriately selected depending on the desired texture. In addition, when the blending ratio of oil and fat is increased, the product becomes rich in oily feel, and when the blending ratio of casein is increased, the product becomes rich in dry feel. If the amount of oil and/or casein applied is too small, the desired nubuck-like surface cannot be obtained, and if the amount of application is too large, excess oil and/or casein will fall off at an early stage, which is not preferable. A part of the applied fat and/or casein is absorbed and retained by the collagen particles, and the rest is filled into the recesses of the uneven surface made of the collagen particles and polyurethane.

These oil and fat and/or casein composition liquids are applied by a roll coating method using a roll such as a roll with cracks or a smooth surface roll, a spray coating method, a surface contact method, and the like. A preferred coating method is a roll coating method because of uniformity of coating and ease of blending onto the surface.

The leather-like sheet obtained by the present invention has good sweat absorption properties, has the smooth texture of natural leather, has a smooth and natural touch similar to natural leather, and has a solid appearance and deep color. The result is a nubuck-like leather-like sheet with a matte, dark appearance and excellent surface strength.

The leather-like sheet material of the present invention is suitable for use in shoe uppers such as sports shoes and men's shoes, bags, bags, clothing, gloves, and the like.

<Examples> Next, embodiments of the present invention will be described using specific examples, but the present invention is not limited to these examples. Note that parts and percentages in the examples are by weight unless otherwise specified.

Example 1 As a base sheet, 20% dimethylformamide (DMF) of polyethylene adipate polyurethane containing a blue colorant was added to an entangled nonwoven fabric of multicomponent fibers containing polyethylene terephthalate as a dispersion component and polyethylene as a dispersion medium component.
) Polyurethane is contained in a porous state in a nonwoven fabric of microfiber bundle fibers obtained by impregnating the solution with a solution, further coating the surface in an amount of 150 g/m'', coagulating in a 40% DMF aqueous solution, and dissolving and removing the polyethylene. A sheet having a polyurethane-containing porous surface layer on one side of the base layer was used.The surface of this base sheet was coated with 30% D of polyester polyurethane.
The average particle size is 5 μm in MF solution for 100 s.Appears to be bulky K O
A composition solution containing 50 parts of collagen powder of 25 g/c ra' and 10 parts of black pigment was applied by a roll coating method using a gravure roll to a coating density of 40 g/ai' and dried. Next, a 20% DMF/) luene solution of natural oils and fats was applied in an amount of 20g/a+'' by a roll coating method using a gravure roll and dried.Next, it was heated at a temperature of 150°C using an embossed roll with a satin pattern. Embossing was performed to create a leather-like sheet A.

The obtained leather-like sheet A has a soft texture, the surface is smooth to the touch like natural leather, and has an oily feel.
It was a nubuck-like leather-like sheet with a deep blackness similar to natural leather and a solid appearance.

When men's shoes and women's shoes were manufactured using this leather-like sheet A, they had a soft calf-like texture, a sharp top line, and a luxurious feel.

Comparative Example 1 In Practical Example 1, the average particle size of the collagen powder was 30
A leather-like sheet B was prepared in the same manner except that collagen powder with μ-positive and apparent bulk density of 0.5 g/clT13 was used.

The resulting leather-like sheet B had a large roughness on the surface and was significantly different from the nubuck-like appearance.

Comparative Example 2 A natural oil and fat solution was applied and dried in the same manner as in Example 1 without applying the polyurethane and collagen composition to the surface of the base sheet of Example 1, followed by heat embossing and rubbing to produce a leather-like sheet C. Finished.

The obtained leather-like sheet C initially had an oily feel, but the oil and fat on the surface quickly fell off and the oily feeling disappeared, resulting in a lack of durability. Furthermore, the surface is almost smooth,
It was far from nubuck-like.

Example 2 As a base sheet, a sheet obtained by impregnating and coagulating polyethylene adipate polyurethane in the same manner as in Example 1 was used in an entangled nonwoven fabric of short polyester fibers having a fineness of 1.5 denier. A composition solution prepared by adding 40 parts of collagen powder with an average particle size of 7 μm, an apparent bulk density of 0.2 g/cm3, and 10 parts of black pigment to 100 parts of a 30% DMF solution of polyester-ether polyurethane was added to the surface of this base sheet. 40g/m" by roll coating method using a gravure roll.
I applied it to fit and dried it. Further, a 20% aqueous solution of casein was spray applied in an amount of 20 g/m'' and dried.

The surface of this sheet-like material was heated and embossed at a temperature of 150° C. using an embossing roll with a kerf #i pattern, to give a leather-like sheet D.

The resulting leather-like sheet D had a moderate firmness, a nubuck-like surface with a smooth feel, and a deep illuminance. When men's shoes and camera cases were made using this leather-like sheet D, they both had excellent shape-forming and shape-retaining properties, and had a unique slimy feel and color tone, giving them high commercial value. .

Example 3 As a base sheet, an entangled nonwoven fabric of multicomponent fibers containing 6-nylon as a dispersion medium component and polyethylene as a dispersion component was impregnated with a 20% DMF solution of polyethylene adipate polyurethane containing a blue colorant, Furthermore, 150g/m on the surface
A microporous surface layer of polyurethane is formed on one surface of the base layer, which contains polyurethane in a porous state on a special porous fiber non-woven fabric obtained by applying the amount of polyurethane in a porous state and coagulating it in a 40% DMF aqueous solution, and then dissolving and removing the polyethylene. A sheet with an average particle size of 7 μm was applied to the surface of this base sheet in a 30% DMF solution of polyester-ether polyurethane.
A composition solution containing 40 parts of collagen powder with an apparent bulk density of 0.2 g/cm3 and 10 parts of black pigment was applied to the surface by a roll coating method using a gravure roll to give an amount of 40 g/m'' and dried. An aqueous liquid composition consisting of 50 parts of milk casein, 30 parts of natural fat emulsion, and 500 parts of water was applied in an amount of 20 g/m2 using a roll coating method and dried to obtain a sheet. Heat embossing was performed using a satin-patterned embossing roll to obtain a leather-like sheet. This leather-like sheet was further rubbed and finished.

The obtained leather-like sheet has a solid appearance but is lightweight, has a nubuck-like surface, a smooth feel, and a deep blackness, and has a load of 500 when measured with a Gakushin type flat abrasion tester.
The abrasion test result of 1000 gs cycles is grade 1 (no abnormalities).

This leather-like sheet was a suitable material for bags, school bags, and sports shoes.

<Effects of the Invention> The leather-like sheet of the present invention has good sweat absorption, has the smooth texture of natural leather, has a smooth and natural touch similar to natural leather, and has a solid appearance and color. It is a nubuck-like leather-like sheet that has a deep, matte look and dark color, and has excellent surface properties such as surface compression resistance, abrasion strength, and scratch resistance.

Claims (1)

[Claims] In a leather-like sheet consisting of a base layer containing a polymer mainly composed of an elastic polymer in the fiber aggregate and a coating layer made of a polymer mainly composed of an elastic polymer, the surface of the coating layer is non-fibrous and has an average Particle size 10μ or less and apparent bulk density 0.1-0.
It has a finely uneven surface made of a mixture of 3g/cm^3 of collagen powder and a polymer mainly composed of polyurethane, and the concave portions of the finely uneven surface are filled with oil and/or casein. Features a nubuck leather-like seat.