JP2515539B2 - Variable color synthetic leather and its discoloration processing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a synthetic leather used for shoes, bags, clothes, etc., which is a variable-color synthetic leather whose hue can be easily changed, and The discoloration processing method is related.

(Prior Art) Conventionally, as a synthetic leather of this type, a polyurethane resin porous layer formed by a colored wet method is formed on a fibrous base material, and this is made uneven by embossing or the like, and heat-compressed by embossing. Those that change the hue were known.

(Problems to be solved by the invention) However, in such a variable color synthetic leather, the processing conditions such as embossing for discoloring are stronger than the processing conditions for squeezing general synthetic leather (for example, (Pressurization, pressurization time and heating temperature are required)
It has been one of the major manufacturing constraints.

In addition, since the colored wet process polyurethane resin layer located on the surface has a fine porous structure, the physical strength, especially the surface abrasion strength, the surface scratching strength and the like are not sufficient. Especially when embossing is not applied enough pressure, that is, the convex part where the porous layer is not densified is the part that is likely to come into contact with other objects when it is put to practical use, but it is the top surface. It is an irrational structure where the strength is weak. Therefore, such a synthetic leather has a problem of practical defects.

The present invention solves the problems of the conventional variable color synthetic leather, and is excellent in variable color synthesis that is difficult to be scratched, is not restricted by manufacturing, and can change the hue to a natural appearance. An object of the present invention is to provide leather and a discoloration processing method thereof.

(Means for Solving the Problems) The first invention of the present invention is to form a colored polyurethane resin porous layer by a wet method having a heat softening temperature of 120 ° C. to 180 ° C. on a fibrous substrate, A variable color synthetic leather characterized in that a transparent non-porous polyurethane resin reinforcing layer having a thickness of 1 μ to 50 μ is formed on a porous layer, and the second invention is, on a fibrous base material, A variable color in which a colored polyurethane resin porous layer having a heat softening temperature of 120 ° C. to 180 ° C. is formed by a wet method, and a transparent non-porous polyurethane resin reinforcing layer having a thickness of 1 μ to 50 μ is formed on the porous layer. Shoes made of synthetic leather,
After processing into a secondary product such as a bag or garment, blowing hot air at a temperature higher than the thermal softening temperature of the polyurethane resin partially forming the porous layer to the secondary product or bringing it into contact with a heating object The present invention provides a method for changing the color of synthetic leather with variable color, which is characterized by imparting a change in hue.

As the fibrous base material in the present invention, natural fibers such as cotton, hemp, and wool, chemical fibers such as rayon and polynosic fibers, synthetic fibers such as polyester, nylon, polyacrylonitrile, and the like, or a mixture thereof is used. Examples include knitted and woven fabrics, knitted and woven raised fabrics, and non-woven fabrics. A so-called wet-impregnated cloth obtained by impregnating or coating a polyurethane resin on these base materials and then wet-coagulating them can also be used as the fibrous base material of the present invention.

The polyurethane resin forming the porous layer according to the present invention is
It is a reaction of a polyol, a diisocyanate and a polyfunctional chain extender. As the polyol, having hydroxyl groups at both ends, polyester polyol, polyether polyol, polyether polyester polyol and the like can be used, as the polyester polyol, for example, adipic acid, an aliphatic dicarboxylic acid such as sebacic acid, and ethylene glycol, Examples thereof include polyester polyols obtained by polycondensation of aliphatic glycols such as butylene glycol and hexamethylene glycol, and polyester polyols having hydroxyl groups at both ends such as ε-caprolactone. Examples of the polyether polyol include polypropylene glycol obtained by polymerizing propylene oxide and polytetramethylene glycol obtained by ring-opening polymerization of tetrahydrofuran. Next, as the diisocyanate, naphthylene diisocyanate, PP'-diphenylmethane diisocyanate, phenylene diisocyanate, aromatic isocyanate such as 2.4 (or 2.6) -tolylene diisocyanate, aliphatic isocyanate such as hexamethylene diisocyanate can be used, and further polyfunctional As the chain extender, it is possible to use a compound having at least two active hydrogen groups in the molecule, for example, hydrazine, ethylenediamine, propylenediamine and other aliphatic diamines, butylene grille, ethylene glycol and other aliphatic glycols. it can.

In the present invention, a polyurethane resin made of these is selected that has good solidification film-forming property by a wet method and has a heat-softening temperature of 120 ° C. to 180 ° C. and is easily heat-deformable. If the thermal softening temperature is less than 120 ° C, stable variable color processing is difficult, and the porous layer to be molded tends to be weakened, which may cause a problem in practical use.
If the temperature is higher than 0 ° C, the desired discoloration may not be sufficiently achieved.

The 100% modulus as a physical property of this polyurethane resin is preferably 10 to 90 kg / cm ² . When the 100% modulus is 90 Kg / cm ² or more, the texture tends to be hard, and when it is 10 Kg / cm ² or less, there is a problem in film forming property during wet coagulation in production.

This polyurethane resin is dissolved in an organic solvent such as dimethylformamide or dimethylacetamide, coated on a fibrous base material to be a resin solution by a conventional method, and wet-solidified to form a porous layer. By the way, in the present invention, it is essential that this porous layer is colored,
As a coloring means, a method of adding a coloring agent such as a pigment or a dye to the polyurethane resin solution or a method of forming a non-colored porous layer and then dyeing it can be adopted.

As the colorant pigment, inorganic pigments such as carbon black and titanium oxide, phthalocyanine-based, anthraquinone-based, azo-based organic pigments and the like can be used, and as the dye, a metal-containing complex hydrochloric acid dye having good solubility in a solvent, etc. Can be used alone or in combination. The amount of these colorants used is preferably at least 1 part by weight based on 100 parts by weight of the polyurethane resin when a sufficient variable color effect is expected. It should be noted that addition of a surfactant, a filler and the like to the polyurethane resin liquid for various modifications may be allowed. The thickness of the porous layer is not particularly limited, since the thickness of the porous layer formed as a synthetic leather of this type generally provides a sufficiently variable color effect. In the present invention, a transparent non-porous polyurethane resin reinforcing layer having a thickness of 1 to 50 is formed on this porous layer.

As the polyurethane resin that can be used, the polyurethane resin mentioned in the explanation of the polyurethane resin forming the porous layer can be used, and 100% modulus is 1 as physical properties.
It is preferably from 0 to 80 kg / cm ² . 100% modulus is 80Kg
If it is / cm ² or more, the feel becomes hard, and if it is 10 kg / cm ² or less, it is not preferable because it becomes soft but the film strength becomes weak and the light resistance is poor. As the heat softening temperature, 120 ℃ ~ 2
Those having 00 ° C. are preferred. At a heat softening temperature of 200 ° C or higher, it is difficult to thermally deform the underlying porous layer, although it has a relationship with the thickness of the reinforcing layer, and thus the effect of variable color processing is not sufficiently exhibited, which is not preferable, and 120 ° C or lower. In that case, the tackiness of the surface becomes remarkable and problems such as adhesion of dust occur in practice, which is not preferable.

In forming the reinforcing layer, the polyurethane resin for forming the reinforcing layer is dissolved in an organic solvent such as dimethylformamide, dimethylacetamide, methyl ethyl ketone, acetone, or toluene, and is used as a lubricant such as silicone, an ultraviolet absorber, an antioxidant, or the like. A stabilizer and a matting agent that does not impair transparency are added as necessary to form a solution.

As a modifier for the polyurethane resin, AS resin (acrylic / styrene resin), acrylic resin or the like may be blended. Then, this resin solution is gravure coater,
Transparent non-porous polyurethane resin on the porous layer by a method of directly coating the porous layer with a knife coater, a reverse low coater or the like, or a method of previously coating the resin solution on a release paper and then transferring it onto the porous layer. A reinforcing layer is formed.

The reinforcing layer has a thickness of 1 μ to 50 μ. If it is 1 μm or less, it is not possible to sufficiently reinforce the intended porous layer. If the thickness is 50 μm or more, the porous layer cannot be easily discolored due to the thickness.

In the present invention, a coloring layer may be further formed on the reinforcing layer by using a coloring treatment agent. As the vehicle for the coloring treatment agent, urethane resin, vinyl chloride-vinyl acetate copolymer, acrylic resin or the like can be used, and as the coloring agent, the above-mentioned pigment and / or dye can be used. The thickness of the colored layer is preferably 5 μm or less in order not to impair the texture, flexibility and variable colorability of the finished synthetic leather. In addition, the coloring treatment agent may be applied uniformly, and the change may be revealed by gravure printing or shading pattern processing by spraying. The thus-obtained variable-color synthetic leather of the present invention is easily discolored by applying heat energy to the polyurethane resin porous layer by a heat-deformable colored wet method having a heat softening temperature of 120 ° C. to 180 ° C. You can

The synthetic leather may be discolored by a heating and pressurizing means such as hot embossing which is generally used for squeezing in a sheet form, but after being processed into secondary products such as shoes, bags and clothing, an electric heater and combustion gas are used. Part of the surface of the secondary product is heated with hot air as a heat source, or the physical properties of an iron, iron, iron, etc. heated by an electric heater, steam, combustion gas, etc. are directly applied to the surface of the secondary product. The method of bringing the layers into contact with each other and partially deforming the structure of the porous layer to change the hue is preferable because color shading and a pattern can be arbitrarily and easily applied.

The temperature of the hot air or the heated object is preferably at least higher than the thermal softening temperature of the polyurethane resin forming the porous layer. Furthermore, the condition to apply hot air, that is, the air volume, distance, time, etc., the condition to contact the heated object, that is, pressure,
The time and the like may be appropriately selected according to the desired variable color effect.

Although the mechanism of discoloration in the present invention is not clear,
The portion processed as described above becomes darker in color than other portions, so that the concentration of the coloring agent contained in the porous layer increases due to thermal deformation of the porous layer, specifically, thermal contraction. It is presumed that the foam structure of the porous layer and / or the porous layer is broken and the resin becomes transparent, resulting in a substantially dark color.

(Effects of the Invention) The variable color synthetic leather of the present invention is soft and has sufficient surface strength, and further, embossing conditions of conventional strength (for example, pressure, pressure time, heating temperature, etc. are increased). It is possible to discolor even under normal embossing conditions used for narrowing, and in addition, depending on the discoloring processing means, it is possible to discolor with almost no unevenness. Is played.

Further, according to the method of discoloring the variable color synthetic leather of the present invention, since the hue can be changed by the simple variable color means after the secondary product is processed, the discoloration is easy and the discoloration at any place is possible. Since it is possible, it can produce a natural hue that is very similar to that of natural leather.

(Examples) Examples of the present invention will be given below, but the present invention is not limited to these examples.

Example 1 A cotton plain weave raised cloth, containing 0.8 mm thick water, squeezed by a squeezing roll to a wet pickup of about 100%, and a heat-deformable polyurethane resin comprising butylene glycol, ethylene glycol, and PP'-diphenylmethane diisocyanate. (100% modulus 20Kg / cm ² , heat softening temperature 130
100 parts by weight, pigment (mixture of carbon black and anthraquinone red) 20 parts by weight, nonionic surfactant 10 parts by weight, anionic surfactant 5 parts by weight, pulp floc 30 parts by weight, dimethylformamide 800 parts by weight. Polyurethane resin solution consisting of was applied at an applied amount of about 850 g / m ² , and was thoroughly desolvated and washed in a water bath and dried.

100 parts by weight of a polyurethane resin composed of butylene glycol, ethylene glycol and PP'-diphenylmethane diisocyanate (100% modulus 40 Kg / cm ² , thermal softening point 130 ° C) on the wet method urethane porous layer thus prepared, an ultraviolet absorber 0.5 parts by weight, dimethylformamide 140
A polyurethane resin solution consisting of 1 part by weight and 160 parts by weight of methyl ethyl ketone was applied twice with a gravure coater (100 mesh roll) to form a 3 μm reinforcing film.

Next, a printing treatment was performed on the reinforcing film by using a urethane printing ink with a gravure coater to give a cloud pattern contrast.

A men's blouson was made from the variable color synthetic leather created in this way, and part of the collar, pockets, sleeves, body, etc. was heated to 130-140 ° C using an electric heater type hot air machine to perform variable color processing. The result was a very natural feel, very similar to natural leather.

Example 2 An impregnated cloth prepared by impregnating a polyester / rayon blended yarn twill woven double-sided raised cloth with a polyurethane resin in advance and wet coagulating it, butylene glycol on a thickness of 1.20 mm, PP'-
100 parts by weight of easily heat-deformable polyurethane resin consisting of diphenylmethine diisocyanate (100% modulus 60 kg / cm ² , thermal softening temperature 150 ° C), pigment (mixture of carbon black, anthraquinone red, titanium oxide) 50 parts by weight,
A polyurethane resin solution consisting of 10 parts by weight of a nonionic surfactant, 10 parts by weight of a pulp block, and 600 parts by weight of dimethylformamide was applied to a coating amount of 1000 g / m ² , and the solvent was thoroughly removed and washed in a water bath and dried.

Next, butylene glycol, ethylene glycol, P.
Polyurethane resin consisting of P'-diphenylmethane diisocyanate (100% modulus 50 Kg / cm ² , thermal softening point 140
℃) 100 parts by weight, UV absorber 0.5 parts by weight, dimethylformamide 140 parts by weight, methyl ethyl ketone 60 parts by weight, a silica-based matting agent 5 parts by weight is applied to the release paper, and this is prepared first. It was transferred onto the wet method urethane porous layer to form a 30 μm reinforcing film.

The women's shoes are made from the synthetic leather with variable color and the electric heater iron is pressed against one part of the shoe, especially the decorative part, and heated to 140-150 ° C to change the color. When processed, the finished product has a natural feel that is very similar to the appearance of natural leather that is said to be burnt.

Claims (4)

(57) [Claims] 1. A softening temperature of 120 ° C. to 180 ° C. on a fibrous base material.
A variable color synthetic leather characterized in that a polyurethane resin porous layer is formed by a wet method colored at 0 ° C., and a transparent non-porous polyurethane resin reinforcing layer having a thickness of 1 μ to 50 μ is formed on the porous layer. . 2. The polyurethane resin porous layer has a thermal softening temperature.
The variable color synthetic leather according to claim 1, characterized in that at least 1 part by weight of the colorant is contained with respect to 100 parts by weight of the polyurethane resin at 120 ° C to 180 ° C. 3. The variable chromaticity according to claim 1 or 2, wherein the transparent non-porous polyurethane resin forming the reinforcing layer has a 100% modulus of 10 to 80 kg / cm ² . Synthetic leather. 4. A softening temperature of 120 ° C. to 180 ° C. on a fibrous base material.
A variable-color synthetic leather having a porous polyurethane resin porous layer formed by a wet method colored at 0 ° C., and a transparent non-porous polyurethane resin reinforcing layer having a thickness of 1 μm to 50 μm formed on the porous layer is used as a shoe, a bag, After being processed into a secondary product such as clothing, a hue is obtained by blowing hot air having a temperature not lower than the thermal softening temperature of the polyurethane resin partially forming the porous layer to the secondary product or bringing it into contact with a heating object. A method for discoloring synthetic leather with variable color, characterized in that: