METHOD FOR PRODUCING FABRIC SUBSTRATE MOLDED PRODUCT COATED WITH SILICONE RUBBER, AND ARTIFICIAL LEATHER-LIKE SHEET MOLDED PRODUCT

Abstract

Provided is a method for producing a fabric substrate molded product coated with silicone rubber, wherein the adherence of dust, flashes during molding, and foreign matter is prevented because the obtained cured coating film has surface lubricity, and breaking and cracking do not occur when the fabric substrate is deformed because the obtained cured coating film has elongation. This method for producing a fabric substrate molded product coated with silicone rubber, in which method the surface of the fabric substrate is coated with a first coating layer and a second coating layer by forming a first coating layer, which comprises a cured product of a liquid silicone rubber composition, on at least one surface of the fabric substrate, and then forming a second coating layer, which comprises a cured product of a silicone rubber composition, on the outer surface of the first coating layer, is characterized in that the first coating layer is a cured product of a liquid silicone rubber composition that contains an adhesiveness-conferring component, and the second coating layer is a cured product of a silicone rubber composition that contains a silicone resin.

Claims

1. A method of manufacturing a fabric-based molded product comprising the steps of applying an adhesion-imparting ingredient-containing liquid silicone rubber composition onto at least one surface of a fabric base and curing the composition so as to form a first coating layer, and subsequently applying a silicone resin-containing silicone rubber composition onto an outside surface of the first coating layer and curing the silicone resin-containing silicone rubber composition so as to form a second coating layer.

2. A method of manufacturing a fabric-based molded product comprising the steps of applying a silicone resin-containing silicone rubber composition onto a surface of a release liner and curing the composition so as to form a second coating layer, and subsequently applying an adhesion-imparting ingredient-containing liquid silicone rubber composition onto an outside surface of the second coating layer, laminating thereon a fabric base and curing the liquid silicone rubber composition so as to form a first coating layer.

3. A method of manufacturing a fabric-based molded product comprising the steps of applying an adhesion-imparting ingredient-containing liquid silicone rubber composition onto at least one side of a fabric base and curing the composition so as to form a first coating layer, and applying a silicone resin-containing silicone rubber composition onto a surface of a release liner, laminating the silicone resin-containing silicone rubber composition-coated surface of the release liner onto the first coating layer and then curing the silicone resin-containing silicone rubber composition so as to form a second coating layer on the first coating layer.

4. The method of manufacturing a silicone rubber-coated fabric-based molded product of any one of claims 1 to 3, wherein the liquid silicone rubber composition used in the first coating layer comprises: (1-A) 100 parts by weight of an organopolysiloxane which contains at least two silicon-bonded alkenyl groups per molecule and has a viscosity at 23 C. of from 0.1 to 2,000 Pa.Math.s, (1-B) from 0.1 to 30 parts by weight of an organosilicon compound of from 1 to 100 silicon atoms which has, per molecule, at least one silicon-bonded hydrogen atom and at least one arylene skeleton and/or a trivalent or tetravalent group with the arylene skeleton from which 1 or 2 hydrogen atoms have been removed, (1-C) from 0 to 20 parts by weight of an organohydrogenpolysiloxane which has at least two silicon-bonded hydrogen atoms per molecule and lacks an arylene skeleton and a trivalent or tetravalent group with the arylene skeleton from which 1 or 2 hydrogen atoms have been removed, (1-D) from 0 to 100 parts by weight of a fine reinforcing silica powder, and (1-E) a catalytic amount of an addition reaction catalyst; and wherein the silicone rubber composition used in the second coating layer comprises: (2-A) 100 parts by weight of an organopolysiloxane containing at least two silicon-bonded alkenyl groups per molecule, (2-B) from 1 to 300 parts by weight of a silicone resin which has R.sub.3SiO.sub.1/2 units (wherein each R is independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 6 carbon atoms) and SiO.sub.4/2 units, the number of moles of R.sub.3SiO.sub.1/2 units per mole of SiO.sub.4/2 units being from 0.5 to 1.5 moles, and which may further have R.sub.2SiO.sub.2/2 units and RSiO.sub.3/2 units (with R in each of these formulas being as defined above) in respective amounts of from 0 to 1.0 mole per mole of SiO.sub.4/2 units, (2-C) from 0.1 to 50 parts by weight of an organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule, and (2-D) a catalytic amount of an addition reaction catalyst.

5. The method of manufacturing a silicone rubber-coated fabric-based molded product of claim 4, wherein component (1-B) is an organosilicon compound of from 1 to 100 silicon atoms which has at least one silicon-bonded hydrogen atom per molecule, has at least one arylene skeleton and/or a trivalent or tetravalent group with the arylene skeleton from which 1 or 2 hydrogen atoms have been removed per molecule, and has one, two or more functional groups selected from among epoxy, alkoxysilyl, ester, acrylic, methacrylic, carboxylic anhydride, isocyanate, amino and amide groups.

6. The method of manufacturing a silicone rubber-coated fabric-based molded product of claim 1, wherein the cured form of the silicone rubber composition used in the first coating layer has a hardness, as measured with a type A durometer in accordance with JIS K6249, of 50 or more.

7. The method of manufacturing a silicone rubber-coated fabric-based molded product of claim 1, wherein the cured form of the silicone rubber composition used in the second coating layer has a hardness, as measured with a type A durometer in accordance with JIS K6249, of 50 or more.

8. A synthetic leather-like sheet-formed product comprising, as silicone rubber coating layers, a first coating layer formed on a surface of a fabric base and a second coating layer laminated onto the first coating layer, wherein the first coating layer is a cured form of an adhesion-imparting ingredient-containing liquid silicone rubber composition, and the second coating layer is a cured form of a silicone resin-containing silicone rubber composition.

9. The synthetic leather-like sheet-formed product of claim 8, wherein the liquid silicone rubber composition used in the first coating layer comprises: (1-A) 100 parts by weight of an organopolysiloxane which contains at least two silicon-bonded alkenyl groups per molecule and has a viscosity at 23 C. of from 0.1 to 2,000 Pa.Math.s, (1-B) from 0.1 to 30 parts by weight of an organosilicon compound of from 1 to 100 silicon atoms which has, per molecule, at least one silicon-bonded hydrogen atom and at least one arylene skeleton and/or a trivalent or tetravalent group with the arylene skeleton from which 1 or 2 hydrogen atoms have been removed, (1-C) from 0 to 20 parts by weight of an organohydrogenpolysiloxane which has at least two silicon-bonded hydrogen atoms per molecule and lacks an arylene skeleton and a trivalent or tetravalent group with the arylene skeleton from which 1 or 2 hydrogen atoms have been removed, (1-D) from 0 to 100 parts by weight of a fine reinforcing silica powder, and (1-E) a catalytic amount of an addition reaction catalyst; and wherein the silicone rubber composition used in the second coating layer comprises: (2-A) 100 parts by weight of an organopolysiloxane containing at least two silicon-bonded alkenyl groups per molecule, (2-B) from 1 to 300 parts by weight of a silicone resin which has R.sub.3SiO.sub.1/2 units (wherein each R is independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 6 carbon atoms) and SiO.sub.4/2 units, the number of moles of R.sub.3SiO.sub.1/2 units per mole of SiO.sub.4/2 units being from 0.5 to 1.5 moles, and which may further have R.sub.2SiO.sub.2/2 units and RSiO.sub.3/2 units (with R in each of these formulas being as defined above) in respective amounts of from 0 to 1.0 mole per mole of SiO.sub.4/2 units, (2-C) from 0.1 to 50 parts by weight of an organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule, and (2-D) a catalytic amount of an addition reaction catalyst.

10. The synthetic leather-like sheet-formed product of claim 9, wherein component (1-B) is an organosilicon compound of 1 to 100 silicon atoms which has at least one silicon-bonded hydrogen atom per molecule, has at least one arylene skeleton and/or a trivalent or tetravalent group with the arylene skeleton from which 1 or 2 hydrogen atoms have been removed per molecule, and has one, two or more functional groups selected from among epoxy, alkoxysilyl, ester, acrylic, methacrylic, carboxylic anhydride, isocyanate, amino and amide groups.

11. The synthetic leather-like sheet-formed product of any one of claims 8 to 10, wherein the cured form of the silicone rubber composition used in the first coating layer has a hardness, as measured with a type A durometer in accordance with JIS K6249, of 50 or more.

12. The synthetic leather-like sheet-formed product of claim 8, wherein the cured form of the silicone rubber composition used in the second coating layer has a hardness, as measured with a type A durometer in accordance with JIS K6249, of 50 or more.

Description

EXAMPLES

[0109] The invention is illustrated more fully below by way of Working Examples and Comparative Examples, although these Examples are not intended to limit the invention. The degrees of polymerization and molecular weights of the respective ingredients are polystyrene-equivalent weight-average values as determined by gel permeation chromatography (GPC). The viscosities are values measured with a rotational viscometer. Also, all references to parts are by weight.

Working Example 1

[0110] A first liquid silicone rubber composition containing the adhesion-imparting ingredient indicated below was applied onto the surface of a fabric base made of PET fibers in an amount such as to give a thickness of 100 m, following which it was cured by heating in a drying oven at 120 C. for 5 minutes.

[0111] Next, a second silicone rubber composition containing the silicone resin indicated below was applied onto a release liner to a thickness of 50 m. This second silicone rubber composition layer coated onto the release liner was then bonded to the side of the fabric base on which the first liquid silicone rubber composition had been applied and cured by heating. The bonded assembly was cured in a drying oven at 120 C. for 5 minutes, thereby giving a silicone rubber-laminated PET fiber fabric base.

[First Liquid Silicone Rubber Composition]

[0112] The following ingredients were mixed together for 30 minutes at room temperature (25 C.): 84 parts of dimethylpolysiloxane (1-A1) (vinyl group content, 310.sup.5 mol/g) capped at both ends of the molecular chain with dimethylvinylsiloxy groups and having a viscosity at 23 C. of 30 Pa.Math.s (average degree of polymerization, about 750), 5 parts of dimethylpolysiloxane (1-A2) (vinyl group content, 6.510.sup.4 mol/g) capped at both ends of the molecular chain with trimethylsiloxy groups, having an average degree of polymerization of about 230 and containing 5 mol % of vinylmethylsiloxane units on side chains (at non-terminal positions along the molecular chain), 40 parts of fumed silica (1-D1) that has a BET specific surface area of 300 m.sup.2/g and is not surface-treated (Aerosil 300, from Nippon Aerosil Co., Ltd.), 8 parts of hexamethyldisilazane as a surface hydrophobizing treatment agent, and 2 parts of water. The temperature of the mixture was then raised to 150 C. and stirring was continued for 3 hours, following which the mixture was cooled, thereby carrying out surface hydrophobizing treatment of the fumed silica and also obtaining a silicone rubber base.

[0113] A liquid silicone rubber composition (viscosity at 23 C., 400 Pa.Math.s) was obtained by uniformly mixing together the following for about 30 minutes: 129 parts of the above silicone rubber base, 40 parts of dimethylpolysiloxane (1-A1) (vinyl group content, 310.sup.5 mol/g) capped at both ends of the molecular chain with dimethylvinylsiloxy groups and having a viscosity at 23 C. of 30 Pa.Math.s (average degree of polymerization, about 750), 2.4 parts of, as a crosslinking agent, methylhydrogenpolysiloxane (1-C1) having pendant SiH groups (a dimethylsiloxane-methylhydrogensiloxane copolymer having a viscosity at 25 C. of 0.010 Pa.Math.s, 34 SiH groups per molecule (SiH group content, 0.0050 mol/g) and capped at both ends with trimethylsiloxy groups), 2.0 parts of an adhesion-imparting ingredient having the phenylene skeleton of formula (1) below (1-B1) (SiH group content, 0.0066 mol/g) [sum of SiH groups in (1-C1) and (1-B1)/sum of vinyl groups in (1-A1) and (1-A2)=2.8 mol/mol], 0.10 part of ethynylcyclohexanol as a reaction regulator, and 0.2 part of platinum catalyst (1-E1) (Pt concentration, 1 wt %).

##STR00010##

[Second Silicone Rubber Composition]

[0114] A silicone rubber composition (viscosity at 23 C., 35 Pa.Math.s) was obtained by uniformly mixing together the following for about 30 minutes: 84 parts of dimethylpolysiloxane (2-A1) (vinyl group content, 310.sup.5 mol/g) capped at both ends of the molecular chain with dimethylvinylsiloxy groups and having a viscosity at 23 C. of 30 Pa.Math.s (average degree of polymerization, about 750), 84 parts of organopolysiloxane resin (2-B1) (number-average molecular weight, 30,000) that has a three-dimensional network structure and consists of (CH.sub.3).sub.3SiO.sub.1/2 units, (CH.sub.2CH)(CH.sub.3).sub.2SiO.sub.1/2 units and SiO.sub.4/2 units, with the molar ratio (CH.sub.3).sub.3SiO.sub.1/2/(CH.sub.2CH)(CH.sub.3).sub.2SiO.sub.1/2/SiO.sub.4/2 being 40/10/50 and the vinyl group content being 0.00054 mol/g, 14.5 parts of, as a crosslinking agent, methylhydrogenpolysiloxane (2-C1) having pendant SiH groups (a methylhydrogenpolysiloxane having a viscosity at 23 C. of 20 mPa.Math.s, 40 SiH groups per molecule (SiH group content, 0.016 mol/g) and capped at both ends with trimethylsiloxy groups [SiH groups in (2-C1)/sum of vinyl groups in (2-A1) and (2-B1)=3.5 mol/mol], 0.10 part of ethynylcyclohexanol as a reaction regulator, and 0.2 part of a platinum catalyst (Pt concentration, 1 wt %).

Working Example 2

[0115] Aside from using 100 parts of organopolysiloxane resin (2-B2) (number-average molecular weight, 5,000; vinyl group content, 0.00027 mol/g) that has a three-dimensional network structure and consists of (CH.sub.3).sub.3SiO.sub.1/2 units, (CH.sub.2CH)(CH.sub.3).sub.2SiO.sub.1/2 units and SiO.sub.4/2 units, with the molar ratio (CH.sub.3).sub.3SiO.sub.1/2/(CH.sub.2CH)(CH.sub.3).sub.2SiO.sub.1/2/SiO.sub.4/2 being 40/5/55, instead of organopolysiloxane resin (2-B1) in the second silicone rubber composition, a silicone rubber-laminated PET fiber fabric base was obtained in the same way as in Working Example 1.

Comparative Example 1

[0116] Aside from not including an adhesion-imparting ingredient having a phenylene skeleton (1-B1) in the first liquid silicone rubber composition [SiH groups in (1-C1)/sum of vinyl groups in (1-A1) and (1-A2)=1.8 mol/mol], a silicone rubber-laminated PET fiber fabric base was obtained in the same way as in Working Example 1.

Comparative Example 2

[0117] Aside from using an additional 84 parts (for a total of 168 parts) of dimethylpolysiloxane (2-A1) (vinyl group content, 310.sup.5 mol/g) capped at both ends of the molecular chain with dimethylvinylsiloxy groups and having a viscosity at 23 C. of 30 Pa.Math.s (average degree of polymerization, about 750) instead of organopolysiloxane resin (2-B1) in the second silicone rubber composition, and 0.56 part of, as a crosslinking agent, methylhydrogenpolysiloxane (2-C1) having SiH groups [a methylhydrogenpolysiloxane capped at both ends with trimethylsiloxy groups; viscosity at 23 C., 20 mPa.Math.s; number of SiH groups per molecule, 40 (SiH group content, 0.016 mol/g)], such that the ratio of SiH groups in (2-C1)/vinyl groups in (2-A1)=3.0 mol/mol, a silicone rubber-laminated PET fiber fabric base was obtained in the same way as in Working Example 1.

[0118] The physical properties (hardness, tensile strength, elongation at break) of the cured forms of the above silicone resin-containing second silicone rubber compositions were measured in accordance with JIS K6249. The cured forms of the silicone rubber compositions were produced by press molding at 120 C. for 10 minutes.

[0119] Also, with regard to the PET fiber fabric bases obtained, adhesion to the fabric base and surface slip were measured by the following methods and evaluated according to the criteria indicated below. The results are presented in Table 1.

[0120] In each of the Working Examples and Comparative Examples, the hardness of the cured form of the first silicone rubber composition, as determined with a type A durometer, was 52.

[Adhesion to Fabric Base]

[0121] The adhesion test was carried out using a Scott-type crease-flex tester under the following conditions. That is, a crease-flex test was carried out ten times at a pressing force of 5 kgf on the above rubber-coated fabric base, following which the state of failure in the coated portion was visually examined. Cases in which the silicone rubber coating layer has not separated from the fabric base are rated as O (adheres), and cases in which the silicone rubber coating layer has separated from the fabric base are rated as X (peeled).

[0122] <Evaluation> [0123] O: adheres [0124] X: peeled (separation between the silicone layer and the base fabric)

[Surface Slip]

[0125] The slipperiness of the surface was evaluated by measuring the dynamic coefficient of friction under the following conditions. That is, the dynamic coefficient of friction was measured using a Type 14FW Surface Property Tester (Shinto Scientific Co., Ltd.) in accordance with ASTM D1894 under the following conditions: load, 100 gf; tensile test speed, 500 mm/min. Specimens having a dynamic coefficient of friction of 0.5 or less were rated as having good slip characteristics (Good), and those having a dynamic coefficient of friction greater than 0.5 were rated as having poor slip characteristics (NG).

[0126] <Evaluation> [0127] O: Surface slip is good [0128] X: Surface slip is poor

TABLE-US-00001 TABLE 1 Working Working Comparative Comparative Example 1 Example 2 Example 1 Example 2 Physical properties of cured form of second silicone rubber composition Hardness (type A 79 70 79 40 durometer) Tensile strength 5.8 5.5 5.8 0.8 (MPa) Elongation at 50 210 50 250 break (%) Evaluation of PET fiber fabric base Adhesion to X X fabric base Surface slip X