JPS60252780A - Preparation of leatherlike sheet material - Google Patents

Abstract

PURPOSE:To obtain the titled sheetlike material having the surface with improved smoothness, by impregnating a solution of a high polymer elastic polymer having a fluorine-containing urethane compound into a fibrous substrate, coagulating the solution in a wet method, drying it, applying a solution of high polymer elastic polymer to the surface of the substrate, coagulating it in a wet method. CONSTITUTION:A fibrous substrate (e.g., woven fabric, etc.) is impregnated with a solution of a high polymer elastic polymer (preferably thermoplastic polyurethane) having preferably 0.03-0.2wt% fluorine-containing urethane compound preferably in DMF, immersed in a non-solvent comprising water as a main component, so that the high polymer elastic polymer is coagulated in a web method. After the drying is over, the surface of the substrate is coated with a solution of high polymer elastic polymer, immersed in a non-solvent comprising water as a main component, similarly coagulated in a wet method, so that a microporous layer is formed to give the aimed sheetlike material. The fluorine-containing urethane compound has preferably 12-35wt% fluorine content, and, for example, is obtained by reacting polyethylene adipate with 2,4-tolylene diisocyanate and perfluoro compound shown by the formula.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a leather-like sheet material having excellent surface smoothness.

Conventionally, a method for manufacturing leather-like sheets involves impregnating the voids of a fibrous base material with a hydrophilic organic solvent solution of an elastomeric polymer such as polyurethane, and then immersing the base material in, for example, water to absorb the organic solvent. The elastic polymer is wet-coagulated by dissolving and removing it in water, and then a solution of an elastomeric polymer such as polyurethane is applied to the surface of this base material, and the elastomeric polymer applied to the surface is wet-coagulated. A method of providing a microporous layer is known. However, according to this method, water etc. permeate into the base material during the wet coagulation process during the formation of the microporous layer, causing air bubbles in the base material to be pushed out and enter the microporous layer during the solidification process. As a result, coarse air bubbles were formed in the microporous layer, and a microporous layer with uniform and dense air bubbles was not formed, resulting in a disadvantage that the surface smoothness of the obtained sheet-like product was reduced.

On the other hand, a method is also known in which the back surface of the base material is water-repellent treated, a solution of polyurethane or the like is applied to the surface opposite to the treated surface, and the polyurethane or the like is wet coagulated to form a microporous layer. (Japanese Unexamined Patent Publication No. 51-61605),
In this method, only the back side of the base material is treated to be water-repellent, and the front side is not treated to be water-repellent or oil-repellent, so water, etc. cannot penetrate from the back side of the base material during the wet coagulation process. Although this is prevented, when a solution such as polyurethane is applied in the previous process, it penetrates into the base material and replaces the air in the base material. There were problems in that air bubbles were extruded and invaded, making it difficult to form a microporous layer with excellent smoothness, and requiring a new process of water repellent treatment, making manufacturing complicated.

The present invention was developed in view of the above points, and the present invention prevents the air bubbles in the base material from transferring to the microporous layer during the solidification process when forming the microporous layer, and forms a microporous layer with a dense and uniform cell structure. An object of the present invention is to provide a method for producing a leather-like sheet material that can produce a leather-like sheet material with excellent surface smoothness.

That is, the method for producing a leather-like sheet material of the present invention involves impregnating a fibrous base material with an elastomeric polymer solution containing a fluorine-containing urethane compound, and then immersing the base material in an aqueous solvent. The elastomeric polymer is wet-coagulated, then dried, the elastomeric polymer solution is applied to the surface, and then immersed in an aqueous solvent to wet-coagulate the elastomeric polymer applied to the surface. This is a book that solidifies to form a microporous layer.

The fibrous base material used in the present invention includes woven fabric,
Examples include base materials having voids inside, such as knitted fabrics and nonwoven fabrics. In addition, examples of elastomeric polymers containing fluorine-containing urethane compounds include polyurethane, polyacrylonitrile, polyacrylic acid ester, etc.; Most preferred are plastic polyurethanes.

In the method of the present invention, the fibrous base material is first impregnated with a solution of the elastomeric polymer containing a fluorine-containing urethane compound, and then the fluorine-containing urethane compound and the elastomeric polymer are wet-coagulated. urge At this time, as the solvent for the elastomeric polymer solution, an organic solvent that can dissolve both the fluorine-containing urethane compound and the elastomeric polymer and has hydrophilic properties is used, such as dimethylformamide, dioxa/, tetofhydrofurin, etc. Among them, dimethylformamide is most preferred. In addition, in order to wet-coagulate the elastomeric polymer, an aqueous solvent containing water as a main component that dissolves the above-mentioned organic solvent but does not dissolve the elastomeric polymer is used. Examples of the fluorine-containing urethane compound include addition reaction products of a urethane prepolymer having an incyanate group at the end and a perfluoroalkyl group-containing compound having an active hydrogen group. The above urethane prepolymers include polyethylene adipate, polybutylene adipate, poly-ε-
Polyester polyols such as cabrolactone, polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 2.4-)lylene diisocyanate, 2.6-lylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, inphorone diisocyanate, xylene diisocyanate),
Urethane prepolymers are preferably obtained by reacting polyisocyanates such as 4.4'-dicyclohexylmethane diisocyanate with polyester polyols, polyether polyols, and other polyols having a molecular weight of 400 to 4,000. Examples of perfluoroalkyl group-containing compounds having active hydrogen groups that can be subjected to an addition reaction with the urethane prepolymer include RIOHXRISO2NH2, RIBO2-N-CH
20H20H.

2 RIS 02- N -0H20H200H20H20
Examples include compounds represented by the general formula: H, R100H2CH20H1 2 (R1 represents a C6-cIB perfluoroalkyl group, R2 represents a C1-C3 alkyl group).

The urethane prepolymer and the perfluoroalkyl group-containing compound are mixed so that the fluorine content in the fluorine-containing urethane compound obtained by the reaction between the two is 12 to 35% by weight. It is preferable to select and use the molecular weight, type, etc.

The amount of the fluorine-containing urethane compound added to the elastomeric polymer is such that the fluorine content in the elastomeric polymer and the fluorine-containing urethane compound is 0.02 to 0.3% by weight, especially 0.
．． An amount of 0.03 to 0.2% by weight is preferred. If the fluorine content of the fluorine-containing urethane compound is out of the range of 12 to 35% by weight, the water repellency of the fluorine-containing urethane compound may decrease, or the fluorine-containing urethane compound may be mixed into the aqueous solvent from the elastomeric polymer. Problems such as dissipation are likely to occur. Furthermore, if the content of the fluorine-containing urethane compound in the elastic polymer is such that the fluorine content is less than 0.02% by weight, it is difficult to obtain sufficient water repellency; Even if the fluorine-containing urethane compound is contained in an amount exceeding this amount, the effect of adding the fluorine-containing urethane compound will not be in an equilibrium state, and further improvement cannot be expected.

However, it is preferable that the elastomeric polymer solution containing the fluorine-containing urethane compound does not contain a surfactant. When a surfactant is added, it is preferable to wet-coagulate the elastic polymer and then thoroughly wash the base material with water to remove the surfactant remaining in the base material. In addition, in order to improve the light resistance, hydrolysis resistance, etc. of the elastic polymer, light resistance improvers such as benzophenone compounds, benzotriazole compounds, hindered phenol compounds, and hindered amine compounds, and polycarbodiimide are added. Even if a hydrolysis inhibitor such as the like is added and used, there is no problem as long as the water repellency is not reduced, and if necessary, a pigment or the like for coloring the fibrous base material can also be used in combination.

The base material is filled with wet coagulated elastomeric polymer.
The substrate is dried so that the aqueous solvent in the substrate is completely removed.

Next, an elastomeric polymer is applied to the base material and wet solidified. At this time, since the base material is dried, it has the effect of improving the adhesive strength with the elastic polymer applied to the surface. Furthermore, since the above-mentioned base material has been dried and has increased hydrophobicity, even when an elastic polymer is applied to the base material and wet-coagulated in an aqueous solvent, the aqueous solvent does not penetrate into the base material. It can prevent air (in the base material) from migrating into the elastomeric polymer during the solidification process, which is caused by the penetration of aqueous solvents into the base material. It is possible to form a microporous layer with a structure.

When the base material is brought into contact with a heating body such as a hot roll or hot plate before drying or after drying, the fibers protruding on the surface of the base material can be collapsed, further improving the surface smoothness. can be done.

The elastomeric polymer applied to the surface of the base material is preferably an elastomeric polymer containing polyurethane nidistomer as a main component, and polyols constituting the polyurethane nidistomer include polyethylene adipate, polyethylene butylene adipate, polyethylene adipate, polyester polyols such as butylene adipate, poly-ε-caprolactone,
Examples include polyether polyols such as polypropylene glycol and polytetramethylene ether glycol, low molecular weight glycols such as ethylene glycol, 1,4-butanediol, and 1,3-butanediol, and polycarbonate polyols.

Examples of polyisocyanates include 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-) lylene diisocyanate, hexamethylene diisocyanate, xylene diisocyanate,
Examples include 4,4'-dicyclohexylmethane diisocyanate, and 4,41-diphenylmethane diisocyanate is particularly preferred. Examples of the solvent for these elastic polymers mainly composed of polyurethane elastomers include the same organic solvents used as the solvents for the elastic polymers impregnated into the base material. After applying the elastomeric polymer solution, the elastomeric polymer applied to the surface of the substrate is solidified by immersing the substrate in an aqueous solvent containing water as a main component, thereby forming a microporous layer. , a leather-like sheet material is obtained.

As described above, according to the present invention, since the high molecular elastic polymer filled in the base material contains a fluorine-containing urethane compound,
The entire base material has excellent water repellency, which makes it difficult for water to penetrate into the base material during wet coagulation of the elastic polymer that forms the microporous layer. There is very little risk that the air bubbles inside will be extruded into the elastomeric polymer during solidification, and the formed microporous layer will not contain coarse air bubbles and will have a dense and uniform cell structure. As a result of the formation of the porous layer, a leather-like sheet material with an extremely smooth surface is obtained. Further, since the aqueous solvent is completely removed from the surface to which the elastomeric polymer solution forming the microporous layer is applied, the adhesive strength between the base material and the microporous layer is improved.

The present invention will be explained in more detail below by giving Examples and Comparative Examples. On the actual flow side, the number in the comparative example indicates the weight.

Example: 10 tlj polyethylene terephthalate fibers with a fiber length of 76 W and a fineness of 6 denier, and 30 tlj polyethylene terephthalate fibers with a fiber length of 51 tlj and a fineness of 2 denier and a fiber length of 29.
Thickness L 2 m, basis weight 3 oar, made of polyethylene terephthalate fibers of 60 cm and fineness L5 denier.
A short fiber entangled body of
Synthesized from 00H20H20H, tolylene diisocyanate, and polyethylene adipate with a molecular weight of 500: Fluorine content 31%) o, o Dimethylformamide solution containing 4s% (fluorine content in the solid content of the total of polyurethane polyurea and fluorine-containing urethane is 0 .124). Next, the liquid was squeezed through squeezing rolls whose roll spacing was adjusted to Ll-, and then immersed in water at 20°C to coagulate the polyurethane polyurea containing fluorine-containing urethane. After washing this material with water and drying it with ventilation at 125°C, he applied a solution of polyurethane polyurea (product name: Crisbon, manufactured by Dainippon Ink Chemical Co., Ltd.) in 25 tidimethylformamide to the surface at a concentration of 800 f/-. Thereafter, the polyurethane polyurea was coagulated by immersing it in water at 20°C. After washing with water and drying with ventilation at 120° C., a leather-like sheet material having a uniform, dense microporous layer and excellent surface smoothness was obtained.

Comparative Example A leather-like sheet material was obtained in exactly the same manner as in the example except that fluorine-containing urethane was not used, but coarse air bubbles were contained in the microporous layer and the surface smoothness was poor. .

May 30, 1980 Kazuo Wakasugi, Commissioner of the Japan Patent Office Patent application filed on May 23, 1980 (2) 2. Name of the invention Method for manufacturing leather-like sheet material 3. Relationship with the person making the amendment case Applicant ([Phase] 160) 22-5 Daikyo-cho, Shinjuku-ku, Tokyo Telephone: 03 (341) 5111 4. Voluntary notice attached to 11 of the amendment order 5. The "Claims" column of the specification to be amended; [T of the invention] J Page 1, line 5 of the specification to page 2, line 1 (Claims) are revised as follows.

[(1) After impregnating a fibrous base material with an elastomeric polymer solution containing a fluorine-containing urethane compound, the base material is immersed in a non-solvent mainly composed of water to form an elastomeric polymer solution. After wet coagulation and drying, an elastomeric polymer solution is applied to one surface, and then the elastomeric polymer solution applied to the surface is immersed in a non-solvent mainly composed of water. Wet coagulation to form a microporous layer f:
A method for producing a leather-like sheet-like material with a % characteristic.

(2) Fluorine content in the fluorine-containing urethane compound is 12
The method for producing a leather-like sheet material according to claim 1, wherein the content is 35% by weight.

(3) The elastic polymer containing the fluorine-containing urethane compound has a fluorine content α of 02 to 03% by weight in the polymer.
A method for producing a leather-like sheet material according to claim 1 or 2, which contains a fluorine-containing urethane compound in an amount such that the amount of the fluorine-containing urethane compound is ” Country Specification page 4, lines 7, 9 to 10, page 7, 2nd line from the bottom, page 9, lines 3, 10, 1
2 lines, 1st line of page 12, replace ``aqueous solvent'' with ``
"A non-solvent whose main component is water."

(3) Page 5, line 14 of the specification, page 11, lines 4 to 5
In each row, the words "aqueous solvent" are corrected to "non-solvent."

Written amendment 1, Indication of the case, Patent Application No. 1983-104160 2, Name of the invention, Method for manufacturing leather-like sheet products 3, Person making the amendment Relationship to the case Applicant (0160) 22 Daikyo-cho, Shinjuku-ku, Tokyo 5 Telephone number 03 (341) 5111 4. Amendment order 1°1 Voluntary 5. Subject of amendment (11 Listed on page 4, line 15 of the specification. Also, fluorine-containing... '' may be mentioned as ``...'' Similarly, the above-mentioned fibrous base material impregnated or coated with a water-soluble polymer compound such as polyvinyl alcohol, hydroxymethyl cellulose, methyl cellulose, etc. can also be used.

It also contains fluorine..." I corrected myself.

Claims (1)

[Scope of Claims] (1) After impregnating a fibrous base material with an elastomeric polymer solution containing a fluorine-containing urethane compound, the base material is immersed in an aqueous solvent to form an elastomeric polymer. After wet coagulating and drying, an elastomeric polymer solution is applied to the surface, and then immersed in an aqueous solvent to wet coagulate the elastomeric polymer applied to the surface to form a microporous layer. A method for producing a leather-like sheet material, characterized by forming a leather-like sheet material. (-4 The fluorine content in the fluorine-containing urethane compound is 12
The method for producing a leather-like sheet material according to claim 1, which has a weight of -35. (3) A patent claim in which the elastic polymer containing a fluorine-containing urethane compound contains the fluorine-containing urethane compound in an amount such that the fluorine content in the polymer is 0.02 to 0.3% by weight. A method for producing a leather-like sheet material according to item 1 or 2.