JP3456668B2 - Manufacturing method of synthetic leather - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a synthetic leather by a dry method using a polyurethane resin solution, which is extremely simple as compared with conventional production methods and has high functionality such as water pressure resistance and moisture permeability. The present invention relates to a method for producing a synthetic leather capable of imparting.

[0002]

2. Description of the Related Art Conventionally, synthetic leather obtained by a dry method has a texture and appearance similar to natural leather, and is therefore widely used in the fields of bags, bags, footwear, clothing and the like.

As a method for producing the same, a one-component type polyurethane resin solution is applied onto a silicone-treated release paper and dried to form a film having a certain thickness, and then a two-component type polyurethane resin solution is applied thereon. Is applied as an adhesive and the base cloth is pasted before drying, or a dry lamination method in which the above two-component type polyurethane resin solution is applied and the base cloth is pasted immediately after drying, that is, the base cloth A method of forming a polyurethane resin film in multiple layers on the top is generally performed.

[0004]

However, in any of the above-mentioned conventional methods, in order to carry out the bonding of the base cloth in a continuous process, the production equipment becomes long and complicated processes are required. In addition, it is not preferable to perform drying and winding each time the polyurethane resin is applied, which is troublesome, inefficient, and costly.

Further, in the case of aiming at a moisture permeable waterproof cloth from the viewpoint of performance, it is necessary to make the polyurethane resin film layer thin in order to realize high moisture permeability, but the method of applying the layers as described above is a thin film. Is difficult to convert.

For this reason, some methods have been used in which the moisture permeability of the surface film is maintained by discontinuously adhering the adhesive with gravure coating or the like. However, this method also has the problems of complicated steps and high cost.

The present invention has been earnestly studied in order to solve the above-mentioned problems in the conventional synthetic leather manufacturing method.
If a mixed solution containing a polyurethane resin having a 00% modulus of 10 to 40 kg / cm ² as a main material and a polyisocyanate curing agent is used, a simple dry method can be used to obtain excellent synthesis such as water pressure resistance and moisture permeability. It has been found that leather can be obtained.

[0008]

That is, the first aspect of the present invention is to apply a mixed solution of a polyurethane resin solution and a polyisocyanate curing agent onto a release paper and dry it to obtain a film immediately after drying. A method for producing synthetic leather, characterized in that a base cloth is heat-bonded to
In the invention described above, a 100% modulus of the dry film is used as the polyurethane resin solution of 10 to 40 kg / cm ^{2. In} the third invention, the mixed solution used in the first invention is the polyurethane resin solution 1
Polyisocyanate curing agent 3 to 20 parts by weight to 00 parts by weight
It consists of parts by weight.

[0009]

The present invention is mainly composed of a soft polyurethane resin having a 100% modulus of 10 to 40 kg / cm ² as described above, to which a polyisocyanate curing agent 3 to 2 is added.
By using a mixed solution containing 0 parts by weight, the obtained film immediately after drying has adhesiveness, and thus has good adhesion to the base fabric to be stuck thereon, and the film is heated by the subsequent heating. The cross-linking reaction by the polyisocyanate curing agent in the mixture proceeds, the adhesion between the film and the base fabric is improved, the tackiness of the film surface is eliminated, and synthetic leather with good smoothness is obtained.

In short, the present invention is comparable to the conventional multi-layered structure or the synthetic leather by the dry method in which an adhesive layer is interposed between the two layers, which is formed by dry-forming a urethane resin film having good adhesion on the base cloth. It is possible to obtain a synthetic leather without.

In the present invention, when the 100% modulus of the polyurethane resin solution as the main material is less than 10 kg / cm ² , the tackiness of the obtained film immediately after drying is too great, and the subsequent heat-bonding of the film and the base fabric. In the above, there is a problem that even if the polyisocyanate curing agent in the coating film is cross-linked, the obtained synthetic leather has a large surface adhesion and thus blocking occurs or the release paper is difficult to peel off.

If it exceeds 40 kg / cm ² , the tackiness of the obtained film immediately after drying is low, so that in the subsequent heat-bonding of the film and the base cloth, even if the polyisocyanate curing agent in the film is used for crosslinking. Even if the reaction is carried out, the adhesion between the film and the base cloth is poor, and a valuable synthetic leather cannot be obtained. Therefore, the polyurethane resin as the main material must have a 100% modulus within the range of 10 to 40 kg / cm ² .

The constituents of the polyurethane resin as described above are not particularly limited, and examples of the polyol include alkylene glycols such as ethylene glycol, propylene glycol and diethylene glycol, and dicarboxylic acids such as succinic acid, adipic acid and sebacic acid. A polyester polyol having a molecular weight of 500 to 5000 consisting of an acid, a polyether glycol such as polyethylene glycol or polytetramethylene glycol, a polycarbonate polyol, or a poly ε-caprolactone polyol is used.

As the organic isocyanate, tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane-4,4'-diisocyanate ( H ₁₂ MDI), isophorone diisocyanate (IPDI) and the like are used.

Next, as the chain extender, glycols such as ethylene glycol, propylene glycol, butylene glycol, hexamethylene glycol and neopentyl glycol, diamines such as ethylenediamine, hexamethylenediamine, isophoronediamine and anhydrous piperazine are used. Can be used.

As the polymerization solvent, various organic solvents such as methyl ethyl ketone (MEK), dimethylformamide (DMF), toluene, xylene, cyclohexanone and tetrahydrofuran can be used.

As the polyisocyanate curing agent added to the polyurethane resin solution obtained by appropriately using the above-mentioned constituents, 1 mol of trimethylolpropane or glycerin is added with 3 mol of TDI or HDI, or HDI is modified with burette or isocyanurate. A modified trimer is used, and if the mixing amount of these curing agents with respect to 100 parts by weight of the polyurethane resin solution is less than 3 parts by weight, the cross-linking reaction at the time of heating and sticking the film obtained by mixing this and the base cloth is caused. If it exceeds 20 parts by weight, the crosslinking reaction will proceed too much and the texture of the synthetic leather will be impaired.
0 parts by weight is suitable.

In the present invention, as the base fabric to be heat-bonded to the coating film comprising the mixture of the polyurethane resin solution and the polyisocyanate curing agent (coating liquid), polyamide, polyester, polyacrylonitrile, polyvinyl alcohol, etc. may be used. Synthetic fibers, cotton, and mixed fibers of these fibers can be used. It is also possible to use a base fabric made of these fibers treated with a polyurethane resin solution and having a microporous layer finished by a wet method. is there.

[0019]

EXAMPLES The present invention will be described in detail below with reference to examples. All parts are parts by weight. Example 1 Polybutylene adipate 1000 having an average molecular weight of 2000
Parts, 1,4-butanediol 45 parts and DMF 118
After charging 8.5 parts into a flask and stirring evenly, T
DI 34.8 parts and dibutyltin dilaurate 0.05 parts were added, and the mixture was heated and stirred at 80 to 90 ° C. for 90 minutes. Then, 200 parts of MDI was added and the reaction was continued at 70 to 80 ° C. As the solution was thickened, 356.5 parts of toluene and MEK were added.
When 832 parts was added and the temperature reached 20000 cps / 30 ° C., monoethanolamine was added to the residual —NCO to stop the reaction, and a polyurethane resin solution having a concentration of 35% was obtained.

A 30-40 μ film formed from this resin solution has a 100% modulus of 28 kg / cm ² .
The film surface was tacky.

To 100 parts of the polyurethane resin solution obtained above, 5 parts of polyisocyanate curing agent (Nippon Polyurethane Industry Co., Coronate HL, 75% concentration), MEK
20 parts were added and mixed uniformly to prepare a coating solution, which was then coated on a silicone-treated release paper with a comma coater.
0 to 50 g / m ² was uniformly applied and dried in a drying oven at 100 to 120 ° C. for about 1 minute to obtain a film. Then, nylon taffeta as a base fabric was pressed on the tacky film immediately after drying with a hot roll at a temperature of 120 ° C., a pressure of 5 kg / cm ² and a speed of 10 m / min to bond them together. Then, after leaving it for 48 hours, the release paper was peeled off to obtain a synthetic leather.

The synthetic leather thus obtained has a soft texture, an adhesive strength of 700 g / cm ² width, and a water pressure resistance of 3000 m.
Results of mH ₂ O were obtained and were found suitable for raincoats.

Example 2 Polytetramethylene glycol 4 having an average molecular weight of 2000
00 parts, 300 parts of polyethylene glycol having an average molecular weight of 1000, 45 parts of 1,4-butanediol and DMF
722.2 parts were charged into a flask and stirred uniformly,
52.2 parts of TDI and 0.03 part of dibutyltin dilaurate were added, and the mixture was heated and stirred at 80 to 90 ° C. for 90 minutes.

Thereafter, 175 parts of MDI was added to 70 to 8
Heat reaction at 0 ℃, when the solution thickens, MEK10
83.3 parts were added, and the viscosity of the reaction solution was 20000 cps /
When the temperature reached 30 ° C, monoethanolamine was added to the residual -NCO in the liquid to stop the reaction, and a 35% concentration polyurethane resin solution was obtained.

A 30 to 40 μ film formed from this resin solution has a 100% modulus of 23 kg / cm ² ,
The film surface was tacky. Using the polyurethane resin solution thus obtained, the synthetic leather obtained in the same manner as in Example 1 had a good texture and an adhesive force of 830 kg / cm ² width,
Water pressure resistance 3000 mmH ₂ O, water vapor transmission rate 4000 g / m ² /
A value of 24 hrs (according to JIS Z-0208) was obtained, and it was confirmed that the synthetic leather is useful as an inner patch for sportswear.

Comparative Example Polybutylene adipate 500 having an average molecular weight of 1000
Parts, ethylene glycol 31 parts and DMF 725.2
Parts into a flask and after stirring uniformly, MDI1
25 parts was added, and the mixture was heated with stirring at 70 to 80 ° C. for 90 minutes. Thereafter, 125 parts of MDI was further added and the reaction was heated at 70 to 80 ° C. MEK725.2 parts were added as the viscosity increased, and when the solution viscosity reached 20000 cps / 30 ° C., monoethanolamine was added to residual NCO. Was added to stop the reaction, and a polyurethane resin solution having a concentration of 35% was obtained.

A 30-40 μm coating made from this resin solution has a 100% modulus of 48 kg / cm ² .
The film surface was poor in tackiness. A coating solution prepared by adding a polyisocyanate curing agent to this resin solution in the same manner as in Example 1 was used to form a film on release paper,
A base cloth was pasted on top of it, but it was not possible to obtain a synthetic leather in which the two were integrally bonded because of poor adhesion.

[0028]

As described above, according to the present invention, a polyurethane resin solution having a 100% modulus of 10 to 40 kg / cm ² is used, and 3 to 20 parts by weight per 100 parts by weight of the polyurethane resin solution is used. By using the coating liquid to which the polyisocyanate curing agent of some parts is added, it is possible to easily obtain a synthetic leather having a single layer, good adhesion to the base fabric, and good texture, water pressure resistance and moisture permeability.

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) D06N 3/14 B32B 27/10 B32B 27/40

Claims (3)

(57) [Claims] 1. Synthetic leather characterized by applying a mixed solution of a polyurethane resin solution and a polyisocyanate curing agent onto release paper and drying the resulting film to heat the base cloth immediately after drying. Manufacturing method. 2. The method for producing synthetic leather according to claim 1, wherein the polyurethane resin solution has a dry film having a 100% modulus of 10 to 40 kg / cm ² . 3. The mixed solution is a polyurethane resin solution 100.
The method for producing synthetic leather according to claim 1, wherein the polyisocyanate curing agent is contained in an amount of 3 to 20 parts by weight based on parts by weight.