JPH086263B2 - Synthetic leather manufacturing method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing synthetic leather, and more specifically, a foam layer has an upper layer in which cells of small diameter are formed and a cell of large diameter. It has an anisotropic foam structure consisting of a lower layer, and therefore it produces fine wrinkles on the surface when folded, is lightweight and flexible, and has excellent texture, so it manufactures synthetic leather that closely resembles natural leather. On how to do.

2. Description of the Related Art In general, synthetic leather is required to have fine wrinkles on the surface when folded, to be light and flexible, and to have a good feel in order to have the same feel and appearance as natural leather. It However, conventionally known synthetic leather has both of the above-mentioned properties at the same time because the resin foam layer on the base cloth has a uniform foam cell and has a uniform isotropic foam structure. Is difficult. That is, if the foamed cells in the resin foam layer are made larger, the texture of the synthetic leather becomes better, but when the synthetic leather is bent, large wrinkles occur on the surface. On the other hand, if the foamed cells in the resin foam layer are made small, when the synthetic leather is bent, fine wrinkles are generated, but the weight is increased and the texture is significantly deteriorated.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention Therefore, as a result of intensive research to solve the above-mentioned problems in conventional synthetic leather, the present inventor has found that the foam layer has an upper layer in which cells of small diameter are formed, and a large diameter. By forming from the lower layer in which the cells are formed, and by having the anisotropic structure in the resin foam layer, as described above, it is possible to cause fine wrinkles on the surface when folded, The present invention has been accomplished by finding that it is lightweight and flexible and has an excellent feeling.

Means for Solving the Problems The first method for producing a synthetic leather having an anisotropic foam structure according to the present invention is a method for producing a synthetic leather in which a resin foam layer and a skin layer are laminated on a base cloth. In 100 parts by weight of polyvinyl chloride paste resin, the upper layer of the foamed layer is formed from a mixture containing 50 to 90 parts by weight of a plasticizer and an appropriate amount of a foaming agent and a stabilizer.
Foamed from a composition which is 70 to 110 parts by weight per 100 parts by weight and which contains a proper amount of a stabilizer and a foaming agent together with a larger amount of the plasticizer than the plasticizer in the composition for the upper layer. A lower layer of the layer is formed, and a cell having a diameter of 80 to 300 μm substantially exceeds a cell number density of 1200 cells / cm ² and 4000 cells / cm ² or less, and a diameter of substantially 200. Form a resin foam layer consisting of a lower layer having a cell number density of 600 cells / cm ² or more and less than 1000 cells / cm ² and having a diameter of ˜900 μm and larger than the diameter of the upper layer. It is characterized by doing.

The second method for producing synthetic leather having an anisotropic foam structure according to the present invention is a method for producing synthetic leather in which a resin foam layer and a skin layer are laminated on a base cloth, and a polyvinyl chloride paste is used. 50 parts of plasticizer to 100 parts by weight of resin
~ 90 parts by weight, forming an upper layer of the foam layer from a mixture containing a proper amount of a foaming agent and a stabilizer, a polyvinyl chloride paste in the composition for the upper layer, a polyvinyl chloride paste having a degree of polymerization smaller than that of the resin From 70 to 110 parts by weight per 100 parts by weight of the resin, and from a composition containing an appropriate amount of a stabilizer and a foaming agent together with a larger amount of the plasticizer than the plasticizer in the composition for the upper layer. The lower layer of the foamed layer is formed, and the cells having a diameter of 80 to 300 μm substantially exceed the cell number density of 1200 cells / cm ² and 4000 cells / cm ² or less. 200-900 μm, and
A cell with a diameter larger than the diameter of the upper layer has a cell number density of 600
Pieces / cm ² or more, and forming a resin foam layer comprising a lower layer are formed by less than 1000 / cm ^2.

In the present invention, the cell number density refers to the number of foam cells per cm ^{2 in} the cross section of the foam structure.

According to the present invention, as described above, a mixture containing a polyvinyl chloride paste resin and an appropriate amount of a foaming agent and a stabilizer together with a relatively small amount of a plasticizer is foamed by heating to form an upper layer. And a relatively large amount of a plasticizer together with an appropriate amount of a foaming agent and a stabilizer are heat-foamed to form a lower layer, and thus, when the composition is heated and melted, the upper layer has a large melt viscosity and the lower layer A synthetic leather having an anisotropic foam structure is formed by forming a small-diameter cell in the upper layer with a foaming agent and a large-diameter cell in the lower layer by having a small melt viscosity. You can

However, in the above, the plasticizer means a plasticizer that gives the same melt viscosity when the same amount is blended in the same polyvinyl chloride paste resin, and is usually the same in the formulation for the upper layer and the lower layer. A plasticizer is used.

In the present invention, as the plasticizer, for example, a phthalic acid ester plasticizer is preferably used. Specific examples of such plasticizers include dibutyl phthalate and dioctyl phthalate. The composition for forming the upper layer in the foamed structure of the synthetic leather has a plasticizer of 50 to 90 parts by weight with respect to 100 parts by weight of polyvinyl chloride paste resin.
The composition for forming the lower layer contains polyvinyl chloride paste resin 10 parts by weight, preferably 60 to 70 parts by weight.
70 to 110 parts by weight, preferably 90 parts by weight, relative to 0 parts by weight
.About.100 parts by weight and contains more than the plasticizer in the formulation for the upper layer. As mentioned above, the composition for the upper layer has a large melt viscosity on heating, and the composition for the lower layer has a small melt viscosity on heating, whereby the anisotropy of the two layers according to the invention is A foamed structure can be formed. Incidentally, as the plasticizer, in addition to the phthalate ester-based one, an epoxy-based plasticizer is also used if necessary.

Further, in the present invention, the polyvinyl chloride paste resin has substantially the same degree of polymerization, has the same melt viscosity when foamed under the same heating conditions using the same amount of the same foaming agent, It means a polyvinyl chloride paste resin that gives a foamed structure having the same cell diameter and cell number density, and usually the same polyvinyl chloride paste resin is used in the formulation for the upper and lower layers.

In the present invention, as the polyvinyl chloride paste resin, those having a polymerization degree of 600 to 3500 are generally preferably used. Further, a vinyl chloride-vinyl acetate copolymer paste resin is also included in the polyvinyl chloride paste resin, and this is used alone or together with the polyvinyl chloride paste resin instead of the polyvinyl chloride paste resin, if necessary. However, as will be described later, in order to more easily control the melt viscosity of each formulation for the upper layer and the lower layer, in each formulation for the upper layer and the lower layer, a polyvinyl chloride paste resin having a different polymerization degree is used. Can also be used.

Furthermore, according to the present invention, as described above, in the formulation for the upper layer and the lower layer, not only the amount of the plasticizer for the polyvinyl chloride paste resin is made different, but also the polyvinyl chloride paste resin in the upper layer has a degree of polymerization of By using a larger one and using a polyvinyl chloride paste resin with a lower degree of polymerization in the lower layer, the melt viscosity of each formulation can be more easily controlled. For this purpose, for example, the polyvinyl chloride paste resin for the upper layer preferably has a degree of polymerization of about 1200 to 3000, and the polyvinyl chloride paste resin for the lower layer is about 700 to 1500. In addition, it is necessary to have a degree of polymerization smaller than that of the polyvinyl chloride paste resin in the formulation for the upper layer.

As the foaming agent, one that decomposes at a relatively high temperature is preferable, and for example, azocarbonamide is preferable. As the foaming agent, a commercially available product can be used, but a fine particle foaming agent having a decomposition temperature of about 200 ° C. and an average particle diameter of about 4 to 8 μm is particularly preferable. Such a foaming agent is usually added in an amount of 2 to 6 parts by weight with respect to 100 parts by weight of the polyvinyl chloride paste resin. As will be described later, the compounding amounts for the upper layer and the lower layer can be different. It is also possible to use different blowing agent particle sizes in the formulations for the upper and lower layers.

Further, according to the present invention, as described above, if only the plasticizer amount in the polyvinyl chloride paste resin composition for the upper layer and the lower layer, or the plasticizer amount and the polymerization degree of the polyvinyl chloride paste resin are made different. (A) By blending a small amount of a foaming agent in the composition for the upper layer and blending a large amount of the foaming agent in the composition for the lower layer, it is possible to reduce the diameter of the upper layer in the upper layer during foaming by heating. A method of forming cells and forming large-diameter cells in the lower layer, (b) adding a foaming agent having a larger particle size to the formulation for the upper layer, and a foaming agent having a smaller particle size in the formulation for the lower layer. A method of adjusting the cell diameter and the cell number density in the foamed structure by appropriately adjusting the compounding amount, and (c) adding a large amount of the cell conditioner to the compound for the upper layer. ,Underlayer By adding a small amount of a cell regulator to the formulation, a method of having a higher melt viscosity in the upper layer during heating and melting the formulation, one or more of the amount of plasticizer in the formulation described above. Alternatively, it may be combined with a method of selecting the amount of the plasticizer and the degree of polymerization of the polyvinyl chloride paste resin.

However, when the above method (a) is adopted, the foaming agent is
This means a foaming agent that forms a foamed structure with the same cell number density under the same heating conditions when the same amount of polyvinyl chloride paste resin is compounded. For 100 parts by weight of vinyl paste resin, 2 to 4 parts by weight are blended, and for the formulation for the lower layer 3
-6 parts by weight, and is blended in a larger amount than that in the formulation for the upper layer.

When the above method (b) is adopted, the foaming agents having different particle sizes mean foaming cells that form foam cells having a smaller diameter as the particle size increases under the same heating conditions. The foaming agent with an average particle size of about 10 to 20 μm is used in the formulation for
Foaming agents that are less than or equal to the extent and have a smaller average particle size than the foaming agents in the formulation for the upper layer are used, respectively.

Further, the cell conditioner used in the above method (c) is
It means a cell modifier that gives the same melt viscosity under the same heating conditions when the same amount of the same polyvinyl chloride paste resin is mixed, and usually the same cell is used in the composition for the upper layer and the lower layer. Modifiers are used. When employing the above method (c), for example, the cell conditioner in the formulation for the upper layer is a polyvinyl chloride paste resin.
It is preferably 1 to 3 parts by weight relative to 100 parts by weight, the cell modifier in the formulation for the lower layer is less than the amount in the formulation for the upper layer, and the polyvinyl chloride paste. 0.5-2 for 100 parts by weight of resin
It is preferably part by weight.

Various cell regulators are commercially available, and any one can be used. For example, BAP-1 (manufactured by Adeka Argus Chemical Co., Ltd.) containing an alkyl methacrylate oligomer, an epoxidized fatty acid glycerin ester and a solvent as main components can be preferably used.

Furthermore, since it is generally known that various stabilizers used in polyvinyl chloride paste resins act as decomposition accelerators or inhibitors of foaming agents, it is necessary to add an appropriate stabilizer to each formulation. This makes it possible to control the foaming of the foaming agent during heating and melting of the composition and facilitate the formation of the anisotropic foamed structure. For example, since a Ba-Nz-based stabilizer accelerates the decomposition of the foaming agent, it is possible to enlarge the foam cells in the lower layer by adding a larger amount to the composition forming the lower layer. Such Ba-Zn
As the system stabilizer, for example, a commercially available stabilizer FL-54 (manufactured by Adeka Argus Chemical Co., Ltd.) containing aromatic carboxylic acid barium salt, aliphatic carboxylic acid zinc salt and a solvent as main components can be preferably used.

Thickeners are also optionally incorporated into the polyvinyl chloride paste resin formulation. The thickener is used to increase the sol viscosity and to improve the coatability when applied on the base fabric. Various such thickeners are commercially available. Used as appropriate.

Furthermore, the compound may contain an appropriate amount of an appropriate compounding agent such as a filler, an antioxidant and a colorant, if necessary.

Synthetic leather according to the present invention, for example, first coated on a release paper with a resin for forming a skin layer, dried, and then
After applying the composition for the upper layer and the lower layer as described above in this order on the upper layer and the lower layer, immediately bond with the base fabric, heat and foam the composition, and after cooling, peel off the release paper. Can be obtained by Incidentally, the heating temperature of the compound is usually appropriate at about 180 to 220 ° C.

In the thus-obtained synthetic leather according to the present invention, the upper layer is substantially formed with cells having a diameter of 80 to 300 μm at a cell number density of more than 1200 cells / cm ² and 4000 cells / cm ² or less. In addition, the lower layer has a diameter of substantially 200 to 900 μm,
In addition, cells having a diameter larger than the diameter of the upper layer are formed at a cell number density of 600 cells / cm ² or more and less than 1000 cells / cm ² .

EFFECTS OF THE INVENTION As described above, the synthetic leather according to the present invention has an anisotropic foam structure in which the foam layer has an upper layer in which cells of small diameter are formed and a lower layer in which cells of large diameter are formed. Since it has a wrinkle, it has fine wrinkles on the surface, is light and flexible, and has excellent texture, so that it is very similar to natural leather. The synthetic leather according to the present invention is suitable, for example, as a cover.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

In Comparative Examples, the following formulations A or B were used. The numbers of parts indicate parts by weight.

Formulation A Number of parts Polyvinyl chloride paste resin (Polymerization degree 1650) 100 Dioctyl phthalate 60 Ba-Zn stabilizer FL54 (manufactured by ADEKA ARGUS CHEMICALS CO., LTD.) 2 cell regulator BAP-1 (Adeka ARGUS chemistry (stock) ) 1 Foaming agent Uniform AZL (azodicarbonamide manufactured by Otsuka Chemical Co., Ltd.) 3 Thickener (manufactured by Shiraishi Industry Co., Ltd.) 4 Blend B Polyvinyl chloride copolymer paste resin (degree of polymerization 1650) 100 Dioctyl phthalate 100 Ba-Zn stabilizer FL54 (manufactured by Adeka Argus Chemical Co., Ltd.) 2 Foaming agent Uniform AZL (azodicarbonamide manufactured by Otsuka Chemical Co., Ltd.) 3 Thickener (manufactured by Shiraishi Industry Co., Ltd.) 4 Example 1 The following formulation C was used for the upper layer and the following formulation D was used for the lower layer. The numbers of parts indicate parts by weight.

Formulation C Number of parts Polyvinyl chloride paste resin (polymerization degree 1650) 100 Dioctyl phthalate 60 Ba-Zn stabilizer FL54 (manufactured by ADEKA ARGUS CHEMICALS CO., LTD.) 2 cell regulator BAP-1 (Adeka ARGUS chemistry (stock) 2) Foaming agent Uniform AZL (azodicarbonamide manufactured by Otsuka Chemical Co., Ltd.) 3 Thickener (manufactured by Shiraishi Industry Co., Ltd.) 4 Compound D Polyvinyl chloride copolymer paste resin (polymerization degree 1200) 100 Dioctyl phthalate 100 Ba-Zn stabilizer FL54 (manufactured by Adeka Argus Chemical Co., Ltd.) 2 Foaming agent Uniform AZL (azodicarbonamide manufactured by Otsuka Chemical Co., Ltd.) 3 Thickener (manufactured by Shiraishi Industry Co., Ltd.) 4 Using these blends, semi-synthetic leather was obtained in the same manner as in Example 1. This semi-synthetic leather has an upper layer foam cell diameter of 170-190 μm and a cell number density of 2700-2900 cells / cm ² , and a lower layer foam cell diameter of 300-400 μm and a cell number density of 700.
It was ~ 750 pieces / cm ² . When it was bent, it had fine wrinkles on the surface, was light and flexible, and had an excellent texture.

Comparative Example 1 The thickness was 10μ after being dried on a release paper with a reverse coater.
Apply a moderately colored polyurethane resin (Resamine 2825LP, Dainichiseika Co., Ltd.) so that the product becomes m.
After heat-drying for 1 minute, PVC sol (Formulation A) was applied with a knife coater to a thickness of 200 μm, heated at 140 ° C. for 2 minutes to be semi-gelled, and the base cloth was immediately laminated. Then
After heat-foaming at 200 ° C. for 1 minute and 30 seconds and cooling, the release paper was peeled off.

The obtained semi-synthetic leather has a homogeneous foam layer, a foam cell diameter of 150 to 200 μm, and a cell number density of 1000 cells / c.
It was m ² . When it was bent, it had fine wrinkles similar to those of natural leather, but lacked in flexibility and had poor texture.

Comparative Example 2 The thickness was 10μ after being dried on a release paper with a reverse coater.
Apply a moderately colored polyurethane resin (Resamine 2825LP, Dainichiseika Co., Ltd.) so that the product becomes m.
After heat-drying for 1 minute, PVC sol (formulation B) was applied with a knife coater to a thickness of 200 μm, heated at 140 ° C. for 2 minutes to form a semi-gel, and the base cloth was immediately laminated. Then 20
After heat-foaming at 0 ° C. for 1 minute and 30 seconds and cooling, the release paper was peeled off.

The obtained semi-synthetic leather was homogeneous throughout, having a foam cell diameter of 300 to 400 μm and a cell number density of 2800 cells / cm ² . It was flexible and lightweight, similar to natural leather, but did not have fine wrinkles on the surface when folded.

Claims (2)

[Claims] 1. A method for producing a synthetic leather comprising a resin foam layer and a skin layer laminated on a base cloth, wherein 50 to 90 parts by weight of a plasticizer is appropriately added to 100 parts by weight of a polyvinyl chloride paste resin. An upper layer of a foam layer is formed from a formulation containing a quantity of a foaming agent and a stabilizer, and a polyvinyl chloride paste resin 10
From 0 to 10 parts by weight, and from a composition containing an appropriate amount of stabilizer and foaming agent together with a larger amount of plasticizer than the plasticizer in the composition for the upper layer. The lower layer of the foamed layer is formed, and the cells having a diameter of 80 to 300 μm substantially exceed the cell number density of 1200 cells / cm ² and 4000 cells / cm ² or less. A resin foam layer composed of a lower layer having a cell number density of 600 cells / cm ² or more and less than 1000 cells / cm ² and having a diameter of 200 to 900 μm and larger than the diameter of the upper layer. A method for producing a synthetic leather, which comprises forming the synthetic leather. 2. A method for producing a synthetic leather comprising a resin foam layer and a skin layer laminated on a base cloth, wherein 50 to 90 parts by weight of a plasticizer is added to 100 parts by weight of a polyvinyl chloride paste resin. An upper layer of a foam layer is formed from a composition containing a foaming agent and a stabilizer in an amount of 100 parts by weight of a polyvinyl chloride paste resin having a smaller degree of polymerization than the polyvinyl chloride paste resin in the composition for the upper layer. 70-1
10 parts by weight, and, with a larger amount of plasticizer than the plasticizer in the formulation for the upper layer, forming a lower layer of the foam layer from a formulation containing an appropriate amount of a stabilizer and a foaming agent, Substantially a cell number density of 1200 cells with a diameter of 80 to 300 μm
Beyond cm ^2, and an upper layer formed by 4000 / cm ² or less, substantially radial 200~900μm der connexion, and the number of cells the cell density 600 having a diameter larger than the diameter of the upper layer / cm ² or more, the method of manufacturing artificial leather, which comprises forming a resin foam layer comprising a lower layer are formed by less than 1000 / cm ^2.