JP2622162B2 - Leather-like sheet and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a leather-like sheet having a soft texture and good shape. Further, the present invention relates to a leather-like sheet having excellent bending fatigue resistance.

[Conventional technology]

2. Description of the Related Art Conventionally, in a method for producing a leather-like sheet, surface patterning is an important step in product planning. The patterning of the surface is mainly performed by embossing with a heating roll or a heating plate, that is, embossing. In the conventional heating embossing method, for example, a polyurethane foam layer made of a specific polyurethane having a softening point of 150 ° C or more and a softening point of 150 ° C or more,
% Modulus 20-200 kg / cm ² Synthetic leather for hot press molding laminated with a coating layer made of polyurethane is disclosed in JP-B-61-43.
No. 471, a polyurethane resin layer having a lower yield value / upper yield value in the range of 0.6 to 0.9 when a stretchable resin primer layer is formed on a base material and a film is stretched thereon. The artificial leather having a deeper grain pattern and a sharper pattern is disclosed in Japanese Patent Publication No. 61-44993, and a fibrous base layer has a porous coating layer of a polymer mainly composed of polyurethane and a softening temperature of 160 ° C. or more. A leather-like sheet suitable for shoe upper covering comprising a non-porous coating layer of a polymer mainly composed of polyurethane and a non-porous coating layer of a polymer mainly composed of a specific polyurethane having a softening temperature of 80 to 160 ° C. Is JP-A-59-22
Japanese Patent No. 8088 further discloses that a leather-like sheet in which a non-porous layer of polyurethane made with a specific composition is laminated on the surface of the porous coating layer, so that a fine emboss pattern can be reproduced. Are described in JP-A-60-119278.

[Problems to be solved by the invention]

In a conventional leather-like sheet, a material configuration and an embossing condition for faithfully forming a fine sculpture pattern have been proposed. In addition, a material configuration for sharpening the shaped pattern has been proposed. However, in order to clearly form a deep uneven pattern or a reptile pattern on a conventional leather-like sheet, embossing has been performed using a high-temperature, high-pressure embossing device. However, since the leather-like sheet is porous and low-density, if deep embossing is performed, the porosity is impaired, and it becomes a plate-like structure, and it has flexibility and drapability as well as a leather-like sheet. The texture becomes significantly worse. Further, disadvantages such as deterioration of bending fatigue resistance and workability of secondary products are caused.

The present invention, in embossing of reptiles and deep irregularities, has a clear shaping property, small decrease in flexibility, bending fatigue resistance, without impairing the workability of secondary products, good texture To provide a leather-like sheet.

[Means for solving the problem]

In the present invention, at least one surface of the fibrous base material layer has a softening temperature of 130 to 185 ° C and a softening temperature of at least 30 ° C lower than the softening temperatures of the main fibers and the main polymer constituting the base layer. A porous or nonporous surface layer composed of a polymer mainly composed of polyurethane, and a nonporous polymer containing a colorant having a softening molding temperature at least 30 ° C. higher than that of the polymer constituting the surface layer. A leather-like sheet having good moldability, characterized by being laminated with a finishing layer.

In addition, the present invention provides that at least one surface of the fibrous base material layer has a softening molding temperature of 130 to 185 ° C., and at least 30% lower than the softening temperature of the main fiber and main polymer constituting the base layer.
A porous or non-porous surface layer composed of a polymer mainly composed of polyurethane having a low softening molding temperature of at least 30 ° C, and a colorant having a softening molding temperature at least 30 ° C higher than the polymer constituting the surface layer. The resulting sheet is embossed at a temperature at which the polymer constituting the surface layer is softened and does not flow-deform the finished layer polymer. A method for producing a leather-like sheet, characterized in that:

Further, the present invention provides a softening molding temperature of at least 130 to 185 on at least one surface of a fibrous base layer containing a polymer mainly composed of an elastic polymer having a higher softening temperature than the polymer constituting the surface layer in the fibrous structure. And a porous or non-porous surface layer composed of a polymer mainly composed of polyurethane at a temperature of at least 30 ° C. higher than the polymer constituting the surface layer. A leather-like sheet having good moldability, wherein a non-porous layer of the layer is laminated and a finishing layer made of a polymer containing a colorant is laminated on at least the surface layer side.

That is, the present invention uses a polymer mainly composed of polyurethane, which can be soft-molded or melt-molded at a lower temperature than the constituent materials of the other layers, for the surface layer constituting the intermediate portion between the fibrous base layer and the surface finishing layer. Therefore, it is possible to reduce the deformation of the base layer and perform clear shaping.

The fibrous base material layer of the present invention comprises polyester fiber, polyamide fiber, polyolefin-based fiber, acrylic fiber, polyvinyl alcohol-based fiber, rayon, collagen fiber, or fiber having a special form thereof (for example, ultrafine fiber or ultrafine fiber bundle). Fiber, special porous array fiber,
A web-like material, a fiber-entangled nonwoven fabric, a woven fabric, a pile or a raised woven fabric, a knitted fabric, and the like, which are formed using at least one kind of fiber selected from the group of irregular cross-section fibers. A fibrous structure such as a pile or brushed knitted fabric, or a composite thereof. One type of fiber structure selected from these fiber structures may be used as it is or at least one fiber structure selected from the group of polyurethane, acrylonitrile-butadiene-based copolymer, styrene-butadiene-based copolymer, and the like.
The base layer is a sheet material selected from fibrous sheet materials in a state in which a fibrous structure contains a kind of elastic polymer or a polymer mainly composed of an elastic polymer in a porous or non-porous state. Things. Preferably, the porous fibrous base apparent density 0.25~0.55g / cm ³ containing a polymer composed mainly of an elastic polymer having at least 30 ° C. higher softening temperature than the softening molding temperature of the polymer constituting the surface layer Layer.

Next, the surface layer of the present invention is a part necessary for shaping the appearance as a leather-like sheet. In particular, in order to form a deep uneven pattern, a surface layer having a constant thickness is provided. Moreover, in the present invention, in order to minimize deformation of the base layer and to form a deep uneven pattern, the polymer constituting the surface layer is composed of the main fiber and the main polymer constituting the base layer, and further, the finish layer constitution The use of a polyurethane-based polymer having a softening temperature at least 30 ° C. lower than the softening deformation temperature of the polymer. The preferred softening temperature of the polymer is in the range of 130 to 185C. The softening molding temperature is desirably low-temperature molding, but at a low temperature of less than 130 ° C., the pattern is deformed or melts under ordinary conditions. For example, when it is processed into a ball, it melts and deforms due to friction with the floor, and when it is processed into clothes, it deforms at ironing and drying temperatures, which is not preferable. Meanwhile, 185
If the temperature becomes higher than ℃, it falls into the same category as conventional leather-like sheets, and it is necessary to perform embossing at high temperature and high pressure. Polyurethane-based polymers having a softening temperature in the range of 130 to 185 ° C. were obtained by condensation polymerization of polymer diols having an average molecular weight of 700 to 3000, for example, low molecular diols and aliphatic or alicyclic dicarboxylic acids. At least one selected from the group consisting of polyester diols, polyether diols obtained by ring-opening polymerization or condensation polymerization, polylactone diols or polycarbonate diols obtained by ring-opening polymerization of lactams, and polyester-ether block copolymer diols. A kind of polymer diol. Organic diisocyanates, for example, at least one organic diisocyanate selected from the group of organic diisocyanates containing an aromatic ring, organic diisocyanates containing a naphthalene ring, aliphatic or alicyclic organic diisocyanates. And low molecular diol, low molecular diamine,
Polyurethane obtained by reacting a low molecular weight compound having two active hydrogen atoms such as low molecular weight dihydrazide or hydroxyamine. In order to convert the polyurethane into a polymer having a desired softening molding temperature, for example, a polymer diol / A method of increasing the amount of the polymer diol component in the polymer composition of the organic diisocyanate / chain extender (the polymer diol component occupying the polymer composition in the range of 75 to 55% by weight);
Selection of the type of organic diisocyanate or a method of forming a composition of a plurality of organic diisocyanates (for example, a composition of an aromatic organic diisocyanate and an alicyclic or aliphatic organic diisocyanate, an organic diisocyanate having a side chain, etc.), chain elongation Selection of the type of the agent or a method of forming a composition of a plurality of organic low molecular compounds (for example, a diol having a large number of carbon atoms, a diol having a large number of carbon atoms having a side chain and / or a diamine), and a polymerization method (for example, producing For polyurethane, the polymerization reaction is performed in a poor solvent or swelling agent system), and the polymerization reaction is performed in combination with one or more of the above methods to sufficiently satisfy the performance as a leather-like sheet. A polyurethane having a low softening temperature can be produced. It is also preferable to add a synthetic rubber, polyvinyl chloride or a vinyl chloride copolymer, a polyester elastomer, a vinyl acetate copolymer, or the like to the polyurethane, if necessary, for the purpose of shapeability or shape stabilization.

The method of processing a polyurethane-based polymer into a surface layer involves dissolving the polyurethane-based polymer in a solvent, or dispersing or slurrying in a dispersant, and, if necessary, a colorant, a filler, and a coagulant. The polymer solution obtained by adding an additive selected from a regulator, a foaming agent, and the like is added to (a) the fibrous structure, (b) the fibrous structure, and the polymer solution or dispersion is added thereto. Is applied to at least one surface of any one of the following fibrous substrates: (c) a fibrous substrate in which a polymer is solidified containing a polymer in a fibrous structure, and the polymer is solidified by dipping in a non-solvent of the polymer. The polymer is solidified into a porous structure or a non-porous structure by a method of solidifying the polymer by heating, or solidifying the polymer by freezing. A solution or dispersion of a polymer mainly composed of polyurethane is cast on a releasable support, and immersed in a non-solvent of the polymer to solidify the polymer or to solidify the polymer by heating. A fibrous base layer and a polyurethane-based layer are obtained by, for example, obtaining a sheet of a united porous structure or a non-porous structure and bonding the polymer sheet to at least one surface of the fibrous base. A sheet-like material comprising the combined surface layer is obtained. In addition, the thickness of the surface layer constituting the leather-like sheet of the present invention is ensured to be sufficient for patterning. Generally, it is in the range of 0.1 to 2.0 mm.

Next, the finishing layer to be laminated on the surface layer consists of a polymer having a softening molding temperature at least 30 ° C. higher than that of the polyurethane constituting the surface layer. When the softening temperature is in the same range as the surface layer constituting polymer, the mold release during embossing is poor, and in addition to the usual conditions, such as friction, impact friction, drying, ironing, daytime automobiles In addition, not only the appearance is impaired due to deformation or abrasion due to being left inside, but also the surface properties are reduced. The polymer used for forming the finishing layer is, for example, a polymer diol, a polyurethane obtained by reacting an organic polyisocyanate and a chain extender, an amino acid resin, a polyurethane / polyamino acid block copolymer, a polyester elastomer, a polyamide elastomer, a polyamide, It is at least one polymer selected from the group of crosslinked polyamide, crosslinked polyurethane and the like. Preferably, the polyurethane has a high softening temperature of at least 180 ° C. The polymer is a polymer solution dissolved in a solvent or dispersed in a dispersant, and the polymer solution is applied directly to the surface layer or applied on a release support to remove most of the polymer solvent or dispersant. After that, a finishing layer is laminated on the surface layer by, for example, transferring to the surface layer. The thickness of the finishing layer varies depending on the intended use of the leather-like sheet, but the preferred thickness range is 3 to 30 μm from the required surface strength, color tone, heat resistance, fold form and the like. Further, the finishing layer contains a coloring agent. The coloring agent may be a method of adding a pigment or a dye to a polymer solution in advance to color the polymer, a method of forming a finishing layer and then dyeing the polymer with a dye, or a combination of the two. The preferred coloring method is determined by the product design of the leather-like sheet. For example,
In the case of sporting goods, a colorant mainly composed of a pigment is added to the polymer liquid to form a finishing layer. In addition, for interior use, clothing, and decoration, a coloring agent mainly containing a dye is added to a polymer solution to form a finishing layer, or a leather-like sheet having the finishing layer formed thereon is dyed with a dye. And, in the leather-like sheet containing a coloring agent at least in the finishing layer, the gloss of the surface can be adjusted, the light stability can be improved, the touch can be improved,
It is preferable to further laminate a thin finishing layer of a polymer or a polymer composition in order to prevent the transfer of the colorant.

The embossing of the leather-like sheet of the present invention does not perform conventional embossing at a high temperature and a high pressure that gives a large deformation to the base layer, but at a temperature sufficient for softening and molding the polymer constituting the surface layer. In addition, embossing is performed with an embossing roll or embossing plate heated to a temperature of 170 to 185 ° C. that does not cause the finished layer polymer to flow-deform at a pressing pressure as low as possible. Prior to embossing, the surface of the leather-like sheet may be provided with a silicone-based, fluorine-based, or polyamide-based release agent. Obtained and preferred. In embossing, adjusting the length of the embossing roll and the tension applied to the leather-like sheet is also an effective means for deep patterning.

The embossed leather-like sheet obtained in the present invention,
Good appearance suitable for basketball balls with deep irregularities, clothes for reptiles, clothes for shoes, etc., with strong surface, strong texture, excellent in secondary product processability Leather-like sheet.

〔Example〕

Next, embodiments of the present invention will be described with reference to specific examples. In the examples, parts and% relate to weight unless otherwise specified.

The softening temperature of the polymer in the examples was JIS K-7206-1.
It is a value measured based on 982 “Testing method of thermoplastic plastic picket softening temperature”.

Example 1 Polyethylene propylene adipate glycol / 4,4'-diphenylmethane diisoanate / ethylene glycol polymerized polyurethane having a softening temperature of 211.degree. Contained thickness 1.2mm, apparent density 0.41g
/ cm ³ of a porous fibrous substrate was prepared.

On the other hand, 1 mol of polybutylene adipate glycol, 4,
Polyester polyurethane [I] having a softening temperature of 165 ° C obtained by reacting 3 moles of 4'-diphenylmethane diisocyanate and 2 moles of a mixed diol of butanediol (0.6) with 3-methyl-1,5-pentanediol (0.4). To prepare a polyurethane composition solution containing 17% of polyurethane [I], 0.5% of a brown pigment, 0.5% of a coagulation regulator, 1% of water, and 81% of dimethylformamide. Next, the polyurethane composition liquid is 110 g as a polyurethane amount on a polyethylene sheet.
/ becomes m ² after the liquid amount applied, dimethylformamide 40
Solidified in 0.3% aqueous solution, thickness 0.36mm, apparent density 0.32
g / cm ³ of a porous polyurethane sheet was obtained. This porous polyurethane sheet was adhered to one surface of a porous fibrous substrate by solvent adhesion to form a surface layer.

Next, for finishing the surface layer, a brown pigment-colored ink for forming a finish layer was prepared using the same polyurethane as the base constituent polyurethane. Apply this colored ink to the surface layer surface with an indented gravure roll of 150 meshes.
Was applied and dried. Further, the same gravure roll is used to apply two layers of the same layer forming ink for adjusting gloss and tactile sensation by adding fine silica powder to the same polymer composition comprising 70% of polyurethane and 30% of polycarbonate, and then forming a porous sheet. A product was obtained.

An embossing roll temperature of 175 ° C is applied to this porous sheet.
When embossing was performed using an embossing roll engraved with a crocodile skin pattern (depth about 0.50 mm) at a surface pressure of 5 kg / cm ² , the uneven pattern was clearly formed. The difference between the irregularities of this leather-like sheet was 0.41 mm on average (molding ratio: 82%), but the thickness of the base layer was hardly reduced, and the leather-like sheet had a soft texture, good touch, and appearance. .

Comparative Example 1 In the production of the leather-like sheet of Example 1, a porous sheet-like material was produced using the same polyurethane as the polyurethane constituting the surface layer as the polyurethane constituting the surface layer.

That is, a porous polyurethane sheet of wet coagulation consisting of polyurethane alone was obtained in the same manner as in Example 1 using the polyurethane constituting the substrate of Example 1 (softening temperature: 211 ° C.). This porous polyurethane has a thickness of 0.34mm and apparent density
It was 0.33 g / cm ³ . Next, this porous polyurethane sheet was adhered to a fibrous substrate in the same manner as in Example 1, and the same crocodile skin-like emboss as in Example 1 was applied to a porous sheet obtained by applying a finishing layer of the same polyurethane. I went. As a result, under the same embossing conditions as in Example 1, the embossing depth was only 0.22 mm (forming ratio 44%). Not only that, the thickness of the fibrous substrate layer was reduced by about 0.1 mm.

Further, in order to approximate the state of the embossed pattern of Example 1, the embossing conditions were changed and the embossing roll temperature 185 was changed.
° C., was treated with a surface pressure of 15 kg / cm ^2, the embossing depth 0.33
mm (molding ratio: 66%), the thickness of one fibrous base material layer was reduced by about 0.25 mm, and the back surface became an embossed uneven pattern. The embossed sheet-like material had a rubber plate-like hard texture.

Comparative Example 2 In performing surface finishing of a sheet-like material obtained in Example 1 in which the porous polyurethane sheet was adhered to one surface of the porous fibrous substrate, a surface layer was formed as a polyurethane of a finishing layer forming ink. Polyurethane [I] (softening temperature 16
5 ° C.), and the surface was color-finished in the same manner as in Example 1 using the adjusted ink to form a finishing layer. Then, the same embossing treatment as in Example 1 was performed. . As a result, the embossing roll strongly adhered to the surface of the sheet-like material, the releasability was poor, and sometimes the surface layer was broken, so that stable embossing could not be performed. Therefore, the embossing conditions were changed so that the embossing roll temperature was 155 ° C and the surface pressure was 10k.
was treated with g / cm ^2, the depth of the embossed surface is 0.17mm
(Molding ratio: 34%), the embossed shape was unclear, and the leather-like sheet had a surface pattern with poor three-dimensional appearance.

Example 2 Using the polyurethane for surface layer constitution [I] of Example 1,
Polyurethane [I] 20%, brown pigment 0.5%, solvent 79.5
% Of a polyurethane composition liquid, and applied on a plastic sheet by casting, and the solvent is heated and evaporated to an average thickness of about
A 0.20 mm non-porous polyurethane sheet was obtained. This polyurethane sheet was adhered to one surface of the porous fibrous substrate of Example 1 by a solvent adhesion method to form a surface layer. Next, a brownish colored ink prepared using the same polyurethane as the base constituent polyurethane was applied with a gravure roll having an indentation of 140 mesh on the surface layer surface in a liquid amount such that the average coating film thickness was about 15 μm,
After drying, the surface gloss adjusting ink prepared by adding fine silica powder to the same polyurethane is further applied with a gravure roll having an indentation of 150 mesh to a liquid amount of an average coating film thickness of about 2 μm, and dried. A porous sheet was obtained.

Next, the embossing roll temperature 170
The embossing process was performed under the conditions of ° C. and a surface pressure of 7 kg / cm ² using an embossing roll (texture depth 0.70 mm) engraved with a texture for basketball. As a result, the emboss depth is 0.
A clear embossed surface of 57 mm (molding rate 81%) was obtained.
On the other hand, the thickness change of the base layer is reduced by only about 0.05 mm,
Flexibility was almost unimpaired.

Comparative Example 3 A non-porous polyurethane sheet having an average thickness of about 0.20 mm was prepared by the same dry method as in Example 2 using the polyurethane constituting the substrate of Example 1 and solvent-bonded to one surface of the porous fibrous substrate of Example 1. The sheet-like material obtained by forming a surface layer by bonding by a method, applying a finishing layer in the same manner and under the same conditions as in Example 2, and embossing the embossed product remains at an emboss depth of 0.25 mm (molding ratio: 36%). Further, the change in the thickness of the base layer was reduced by about 0.15 mm, the texture was rubber-like hardness, and the embossed pattern was unclear and poor in three-dimensional appearance.

〔The invention's effect〕

The leather-like sheet of the present invention is suitable for embossing of a deep uneven pattern, the deep uneven pattern can be clearly formed, and the leather-like sheet after embossing has a small thickness deformation, has a soft texture, and has a strong surface. Thus, for example, it has high frictional strength due to friction and impact, and has excellent secondary product workability.

The embossed leather-like sheet of the present invention is used for sports goods such as raw materials for basketball, shoes, bags,
It is suitable for applications such as clothing.

Claims (2)

(57) [Claims] 1. A softening molding temperature of 130 to 185 ° C. and at least 30 ° C. lower than the softening temperatures of the main fibers and the main polymer constituting the base layer on at least one surface of the fibrous base layer. A porous or non-porous surface layer composed of a polymer mainly composed of polyurethane having a non-porous polymer containing a colorant having a softening molding temperature at least 30 ° C. higher than that of the polymer constituting the surface layer. A leather-like sheet having good moldability, characterized by being laminated with a quality finishing layer. 2. A softening and molding temperature of 130 to 185 ° C. and at least 30 ° C. lower than the softening temperatures of the main fibers and the main polymer constituting the base layer on at least one surface of the fibrous base material layer. A porous or non-porous surface layer composed of a polymer mainly composed of polyurethane having a non-porous polymer containing a colorant having a softening molding temperature at least 30 ° C. higher than that of the polymer constituting the surface layer. And the resulting sheet is embossed at a temperature at which the polymer constituting the surface layer is softened and formed, and at a temperature at which the finished layer polymer does not undergo flow deformation. Manufacturing method of leather-like sheet.