JPH05222681A - Synthetic leather - Google Patents

Abstract

PURPOSE:To provide a dry-touch synthetic leather having suppressed surface gloss and deep and clear grain pattern without lowering jet black color. CONSTITUTION:A surface skin layer 3 composed of a polyurethane resin and containing collagen fine powder 4 is integrally applied to the whole surface of a microporous layer 2 on a substrate 1 used as a base. The laminate is crumpled in warm water to form a microporous structure 5 on the surface and a collagen fiber texture 6 in the surface skin layer 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic leather which uses a polyurethane resin for its skin layer.

[0002]

2. Description of the Related Art Generally, synthetic leather is prepared by applying a hydrophilic organic solvent solution of polyurethane resin to a substrate made of woven fabric, knitted fabric, non-woven fabric, etc., and then immersing it in water to dissolve and remove the organic solvent. Is solidified to form a wet microporous layer of polyurethane resin, and then a skin layer of polyurethane resin is formed on the surface of the wet microporous layer.

[0003] Conventionally, in order to obtain a natural leather-like appearance, texture, and grain pattern on synthetic leather, the surface of the surface is obtained by transferring the grain pattern attached to the release paper to the surface layer or by rubbing while applying heat. There is known a method of imparting a texture pattern to.

However, according to these methods, the appearance and texture of the natural leather are not sufficient, and a skin layer obtained by adding a fine powder of natural leather to a polyurethane resin was used and formed on the microporous layer. After that, a method of rubbing treatment was developed while heating or heating in water or in a humidified atmosphere (see JP-A-2-127574).

According to this method, by rubbing, a deep squeezing pattern having moisture permeability and hygroscopicity and a dry touch and a low surface gloss can be obtained. Although the reason is not always clear, since the fine natural leather powder in the epidermis layer has hydrophilicity, it swells to cause strain in the epidermis layer, and the contraction of this base material and the swelling of the fine natural leather powder swell the epidermis. Layer distortion,
It is believed that this is due to the synergistic effect with wrinkles caused by the rubbing treatment.

When the rubbing treatment is carried out in water, the water-soluble natural leather fine powder is dissolved and removed in water, leaving pores on the surface of the epidermis layer to form a microporous structure. The fine powder of natural leather contains glue, starch, casein, collagen and the like.

[0007]

However, since the synthetic leather obtained by the above method has a low surface gloss, there is a problem that the jet blackness cannot be sufficiently expressed in the depth of color, especially in the case of black. is there.

The object of the present invention is to further improve the properties of the above-mentioned synthetic leather, to exhibit a deep and clear squeezing pattern with less surface gloss, without impairing jet blackness, and to provide excellent moisture permeability with dry touch. To provide synthetic leather having hygroscopicity.

[0009]

In order to achieve the above object, the synthetic leather according to the present invention is a synthetic leather having a microporous structure and a fibrous structure in the epidermal layer, the epidermal layer containing collagen powder. Made of polyurethane resin,
It is laminated and integrated on the base material, and the microporous structure is
It is a hole where collagen powder has fallen out of the polyurethane resin of the epidermis layer, is formed on the surface of the epidermis layer, and the fibrous structure is
It is a fiber of collagen and is formed inside the epidermis layer.

[0010]

In the synthetic leather according to the present invention, a surface layer of polyurethane resin containing fine collagen powder is formed on a release paper, and then the surface layer and, as a base material, one side of a fibrous base material are used to form microporous polyurethane resin. After the wet bases in which the layers are laminated and integrated are stacked and bonded by heating and pressurizing, the release paper is peeled off, and the base material, the microporous layer and the skin layer are rubbed in warm water. Obtained by

The synthetic leather obtained is shown in FIG. The synthetic leather according to the present invention has a laminated structure of a base material 1, a microporous layer 2 and an epidermis layer 3. Before rubbing, as shown in FIG. Although the powder 4 is uniformly distributed, after the rubbing process in warm water, as shown in FIG. 1 (b), the collagen fine powder on the surface portion of the epidermis layer 3 has fallen off and has a microporous structure. 5, the collagen fiber tissue 6 is formed inside the epidermis layer 3.

The microporous structure 5 on the surface reduces the surface glossiness of the synthetic leather and allows the synthetic leather to have a moisture permeability and a dry touch.
It gives hygroscopicity, and the internal fibrous structure 6 gives depth to the squeeze pattern and contributes to the improvement of hue and sharpness. The deep hues exhibit excellent jet blackness, especially when black.

Collagen has a primary structure of a polypeptide, and as a higher-order structure, three molecules of the polypeptide are entangled with each other, and a collagen molecule having a triple helix structure is a unit structure. As a natural protein fiber, collagen is present in large amounts in vertebrate skins, bones, tendons and the like.

In mammals, it is said that 1/3 of the total protein amount is collagen, particularly 90% or more in bones and tendons and 50% or more in skin. Collagen is soluble, so by rubbing in warm water, those that come in contact with water will elute and fall off from the epidermis layer, but the collagen trapped inside the epidermis layer will
It is not always clear why it becomes fibrous. Collagen powder, which is probably a mass of fibers, is supposed to be loosened and returned to a fibrous form.

The collagen fiber structure is extremely effective in creating an appropriate stress state in the epidermis layer and creating a depth in the unevenness of the wrinkles formed by the drawing or rubbing process transferred from the release paper for a clear expression. And this action is unique to collagen.

The rubbing process is preferably carried out using a jet dyeing machine, a washer processing machine or the like. The skin layer may be multi-layered. In this case, the same type of polyurethane resin may be used, or different types of polyurethane resins may be applied repeatedly. An adhesive layer may be provided between the skin layer and the wet base. A two-component polyurethane resin adhesive can be used as the adhesive. Further, the wet microporous layer may be a dry foam layer. Further, a constitution of a film layer / adhesive layer / base material without a foam layer may be used.

The collagen fine powder added to the epidermis layer is obtained by finely pulverizing collagen fibers into a powder form, and preferably has a particle size of 30 μm or less. Addition amount is 1-10
0% by weight, especially 5 to 50% by weight is preferred. The effect of the fine collagen powder can be obtained by including it in at least the uppermost layer of the construct, but the effect becomes more remarkable as it is included in the lower layer.

[0018]

EXAMPLES Examples of the present invention will be described below.

(Example 1) A polyester fiber and a rayon fiber were mixed and spun on a raised surface of a 0.7 mm-thick raised cloth to give 10
After applying a 12% DMF solution of a polycarbonate-based polyurethane resin having a 0% modulus of 35 Kg / cm ² ,
The polyurethane resin is solidified by immersing in water at 20 ° C to remove the solvent, dehydrated, and then dried under hot air at 120 ° C to a thickness of 20.
A 0.9 mm thick substrate with a wet microporous layer of 0 μm was obtained.

On the other hand, a 20% DMF-MEK solution of a polycarbonate-based polyurethane resin having a 100% modulus of 90 kg / cm ² containing 30% by weight of collagen fine powder having an average particle size of 9 μm on a release paper (black coloring agent 20 parts by weight per 100 parts by weight of polyurethane resin was applied by a knife coater so that the thickness after drying would be 30 μm, and dried at 90 ° C. for 2 minutes to form a skin layer of polyurethane resin. The surface of the microporous layer of the substrate having the microporous layer is heated and thermocompressed at 140 ° C. while being adhered, the release paper is peeled off, and the surface layer of the polyurethane resin containing the fine collagen powder is transferred to the surface of the substrate. Laminated.

Then, the obtained laminate was subjected to a rubbing treatment with a jet dyeing machine (cloth speed: 200 m / min, bath ratio: 1:30, nozzle pressure: 3 kg / cm ² ) to obtain a synthetic leather. Electron micrographs of the surface and cross section before the rubbing treatment are shown in FIGS. 2 (a) and 2 (b), and electron micrographs of the surface and cross section after the rubbing treatment are shown in FIG. 3 (a).
It shows in (b).

Example 2 A 100% modulus is 1 on the raised surface of a raised cloth made of rayon fiber and having a thickness of 0.5 mm.
After applying a 10% DMF solution of 5 kg / cm ² of polycarbonate-polyether polyurethane resin, 20
Soaked in water at ℃, desolvated to coagulate polyurethane resin, dehydrated and dried under hot air at 120 ℃ and thickness 200μ
A 0.7 mm thick substrate with m wet microporous layer was obtained.

On the other hand, a 20% DMF-MEK solution of a polycarbonate-based polyurethane resin having a 100% modulus of 90 kg / cm ² containing 30% by weight of collagen fine powder having an average particle size of 9 μm on a release paper (a black coloring agent 20 parts by weight per 100 parts by weight of polyurethane resin was applied by a knife coater so that the thickness after drying would be 10 μm, and dried at 90 ° C. for 2 minutes to form a skin layer of polyurethane resin. % Modulus is 60kg
/ Cm ² of 20% D of polyether polyurethane resin
MF-MEK solution (Polyurethane resin 10
(20 parts by weight per 0 parts by weight) has a thickness of 20μ after drying.
m by a knife coater and dried at 90 ° C. for 2 minutes to form an intermediate coating layer of polyurethane resin,
The microporous layer surface of the substrate having the microporous layer is bonded by thermocompression bonding at 140 ° C. while heating, and then the release paper is peeled off to transfer the skin layer of the polyurethane resin containing the collagen fine powder to the substrate surface. Laminated.

Then, the laminate obtained in the same manner as in Example 1 was subjected to a kneading treatment with a jet dyeing machine (cloth speed: 200 m / min,
A synthetic leather having a bath ratio of 1:30 and a nozzle pressure of 3 kg / cm ² was obtained.

Comparative Example 1 Synthetic leather was obtained in the same manner as in Example 1. However, collagen fine powder was not added to the epidermis layer. Electron micrographs of the surface and the cross section before the rubbing treatment are shown in FIGS. 4A and 4B, and electron micrographs of the surface and the cross section after the rubbing treatment are shown in FIGS. 5A and 5B.

Comparative Example 2 Synthetic leather was obtained in the same manner as in Example 1. However, gelatin was used in the epidermis layer instead of collagen fine powder. Electron micrographs of the surface and cross section before the rubbing treatment are shown in FIGS. 6 (a) and 6 (b), and electron micrographs of the surface and cross section after the rubbing treatment are shown in FIGS. 7 (a) and 7 (b).

Comparative Example 3 A synthetic leather was obtained in the same manner as in Example 2. However, collagen fine powder was not added to the epidermis layer.

Comparative Example 4 A synthetic leather was obtained in the same manner as in Example 2. However, gelatin was used in the epidermis layer instead of collagen fine powder.

Comparative Example 5 In the same manner as in Example 1, a skin layer of polyurethane resin containing fine collagen powder was transferred and laminated on the surface of the substrate. However, no rubbing treatment was performed.

Surface photographs in FIGS. 2 to 7 are x2000.
The cross section photograph is × 1500 times.

As is apparent from the comparison between FIG. 2 and FIG. 3, according to the first embodiment, the rubbing treatment in warm water provides
A microporous structure is formed on the surface, and a fibrous structure is formed on the cross section. This is basically the same also in the second embodiment.

According to Comparative Example 1, since no collagen fine particles are contained, there is no particular change before and after the rubbing treatment as shown in FIGS. 4 and 5, and the rubbing treatment is such that wrinkles are formed on the surface. It's just a change.

In Comparative Example 2 in which gelatin was used instead of collagen fine powder, the microporous structure common to water-soluble natural leather fine powder was formed by the rubbing treatment in warm water as shown in FIGS. However, the fibrous structure is not formed in the epidermis layer as in the case of using the collagen fine powder.

The following tests were conducted for the effect of using the collagen fine powder.

(Performance Test of Synthetic Leather) The synthetic leathers obtained in Examples 1 and 2 and Comparative Examples 1 to 5 were evaluated for their performances (glossiness, jet blackness, depth of diaphragm, moisture permeability, water pressure resistance, moisture absorption). Shown in the table below. -Glossiness: Measured with a specular glossiness meter that has an optical system with an incident angle of 75 ° and a light receiving angle of 75 ° (manufactured by Murakami Color Research Laboratory)
(Unit:%), jet blackness, depth of diaphragm: visually determined, moisture vapor permeability: according to JIS Z-0280 (unit: g / m ²
・ 24 hrs) ・ Water pressure resistance: According to JIS L-1092 (Unit: mm water column) ・ Hygroscopicity: 1 hour in an atmosphere of 40 ° C × 90% humidity compared to the weight in an atmosphere of 40 ° C × 40% humidity Weight increase rate after leaving (unit:%).

[0036]

[Table 1]

As is apparent from Table 1 above, according to the examples of the present invention, the effect of exceeding the performance of the comparative example in all the performances of glossiness, jet blackness, moisture permeability, water pressure resistance and hygroscopicity. was gotten. In addition, in Comparative Examples 2 and 4 in which gelatin was added, a considerable sharpness was obtained in terms of the depth of the diaphragm, but
It was inferior to Examples 1 and 2 in terms of tightness and dense definition. According to the present invention, it is considered that the collagen fibers in the epidermis layer exert a stress on the surface to enhance the three-dimensional effect and contribute to the formation of a deep and clear striation pattern by densely modifying the striation pattern. ..

[0038]

As described above, according to the present invention, the characteristics of collagen powder are effectively utilized, the moisture permeability and the hygroscopicity are not impaired, the surface glossiness is small, the hue is deep, and particularly black In this case, it is excellent in jet blackness, the surface touch is dry, and it is possible to express a deep and sharp squeezing pattern, which is excellent as a synthetic leather for furniture, vehicle interior materials, bags, shoes, clothing, and miscellaneous goods. Obtainable.

[Brief description of drawings]

FIG. 1 shows a synthetic leather showing one embodiment of the present invention,
(A) is a schematic diagram before a rubbing process, (b) is a schematic diagram after a rubbing process.

2 is an electron micrograph before rubbing treatment in Example 1, FIG.
(A) shows a surface and (b) shows a cross section.

FIG. 3 is an electron micrograph after rubbing treatment in Example 1,
(A) shows a surface and (b) shows a cross section.

FIG. 4 is an electron micrograph before rubbing treatment in Comparative Example 1,
(A) shows a surface and (b) shows a cross section.

5 is an electron micrograph of the rubbing treatment of Comparative Example 1,
(A) shows a surface and (b) shows a cross section.

6 is an electron micrograph before rubbing treatment of Comparative Example 2,
(A) shows a surface and (b) shows a cross section.

7 is an electron micrograph of Comparative Example 2 after rubbing treatment,
(A) shows a surface and (b) shows a cross section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Microporous layer 3 Epidermal layer 4 Collagen fine powder 5 Microporous structure 6 Fiber structure

Claims (1)

[Claims] 1. A synthetic leather having a microporous structure and a fibrous structure in an epidermis layer, wherein the epidermis layer is made of a polyurethane resin containing collagen powder and is laminated and integrated on a base material. The porous structure is a hole in which collagen powder has fallen out of the polyurethane resin of the epidermis layer, is formed on the surface of the epidermis layer, and the fibrous tissue is a fiber of collagen, which is formed inside the epidermis layer. Synthetic leather characterized by.