JPH0126336B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing silicone elastomer coated fabrics.

Several methods are known for producing silicone elastomer-coated fabric in which one or both sides of the fabric are coated with silicone elastomer.

For example, a method of calendering an organic peroxide-containing silicone rubber stock on a cloth and curing it by heating in hot air, or a method of applying a condensation reaction-curable silicone rubber dispersion or an organic peroxide-containing silicone rubber dispersion on a cloth. A method of coating, air drying, and then heating and curing (see Japanese Patent Publication No. 50-3436),
A method in which a net of nylon or the like is placed on a tetrafluoroethylene resin film, a condensation reaction-curable silicone rubber dispersion is applied thereon, and the dispersion is peeled off from the film after being heated and cured (see Japanese Patent Publication No. 42-2687). , and coating a moisture-curable silicone elastomer composition on polytetrafluoroethylene film, polyethylene film or paraffin-coated paper, pressing the reticulated material onto the semi-cured silicone elastomer, and then, after complete curing, forming the film or paper. A method of peeling it off (see Japanese Patent Publication No. 49-20939) is known.

However, the former two methods have the disadvantage that it is difficult to reduce the thickness of the silicone rubber layer, and that it is difficult to coat the cloth with a uniform thickness when the cloth is stretchable.

The method described in Japanese Patent Publication No. 42-2687 has the disadvantage that because the tetrafluoroethylene resin film is made by cutting, there are minute irregularities on the surface, resulting in minute irregularities on the surface of the cured silicone elastomer, and the problem of silicone rubber curing. The disadvantage is that the film expands and sag due to heating, making it impossible to obtain a cured silicone rubber layer of uniform thickness.

The method using polyethylene film or paraffin-covered paper described in Japanese Patent Publication No. 49-20939 is as follows:
The disadvantage is that it is difficult to peel off the cured silicone rubber and the silicone rubber gets scratched, and when polyethylene film is used, the film may melt or sag during the heating to cure the silicone rubber, resulting in a layer of cured silicone rubber with a uniform thickness. The disadvantage is that it cannot be obtained.

The inventors of the present invention have conducted intensive research to eliminate the drawbacks of conventionally known manufacturing methods for silicone elastomer-coated fabrics, and as a result, have come up with a new manufacturing method that does not have these drawbacks.

An object of the present invention is to provide a method for manufacturing a silicone elastomer-coated cloth that can efficiently manufacture a silicone elastomer-coated cloth having a silicone elastomer layer with a smooth surface and a uniform thickness.

That is, the present invention covers a coated paper with a liquid-length thermosetting addition-reactive silicone elastomer composition, laminates a cloth thereon, heat-cures the silicone elastomer composition, and then coats the coated paper with the silicone elastomer. In a method for manufacturing a silicone elastomer-coated cloth by peeling the cloth from coated paper, the peel resistance value of the coated surface of the coated paper to the cured silicone elastomer is
The present invention relates to a method for producing a silicone elastomer-coated fabric, characterized in that the weight loss is 50 g/cm or less under the conditions of 25° C., a peeling speed of 5 m/min, and a peeling angle of 180°.

To explain this, coated paper is paper such as glassine paper, kraft paper, parchment paper, etc. coated with synthetic resin, synthetic polymer, or other material evenly and smoothly. Anchor coating may be performed in advance with alcohol or CMC. The coated surface of this coated paper was coated with a liquid thermosetting addition-reactive silicone elastomer composition, a fabric was laminated on top of the coated paper, and the coating was heat-cured. angle
50g or less when peeled off at 180°
It has a resistance value of cm. As long as it has this peeling performance, the type of coating material does not matter, and the coating material may be one type or a mixture of two or more types of coating materials, It may be solid or liquid, or it may be a liquid coating material applied or adhered to a surface coated with a solid material. However, since liquid coatings tend to soak into paper, it is preferable to use them together with solid coatings.

Solid coating materials having such peeling properties include triacetylcellulose, diacetylcellulose, polyperfluoroalkyl methacrylate, perfluoroalkyl polyacrylate,
Examples include perfluoroalkyl methacrylate/perfluoroalkyl acrylate copolymer, perfluoroalkyl methacrylate/ethylene copolymer, and polytetrafluoroethylene wax.

In addition, as resins for coatings coated with or attached with a mixture of resin and liquid coating or a liquid mold release agent that has such peeling performance, nitrocellulose, polyethylene, polypropylene, ethylene propylene copolymer, polyethylene Examples include terephthalate, polyamide, vinylidene chloride/vinyl chloride copolymer, vinylidene chloride/acrylic acid alkyl ester copolymer, ethylene/vinyl acetate copolymer, and alkyd resin. Examples include polymerized products, perfluoroalkanoic acid esters, and fluorinated hydrocarbon oils.

The peeling performance of the resin surface against the cured silicone elastomer was measured at 25°C, peeling speed of 5 m/min, and peeling angle.
Less than 50g/cm when peeled off at 180°
The resistance value was chosen because if it exceeds this value, it will be difficult to remove the silicone elastomer-coated fabric from the coated paper, and if the silicone elastomer layer is forcibly removed, the silicone elastomer layer will be damaged. Even so, the speed must be significantly slowed down, which reduces productivity.

The addition-reactive silicone elastomer composition in the liquid thermosetting addition-reactive silicone elastomer composition used to coat fabrics consists of functional groups bonded to silicon atoms constituting the organopolysiloxane and another organopolysiloxane. It refers to a type of elastomer that is formed by crosslinking and forming an elastomer by bonding with functional groups bonded to the silicon atoms constituting it through an addition reaction.A typical example is an organopolysiloxane containing an aliphatic unsaturated group such as a vinyl group and This is a silicone elastomer composition that is cured by an addition reaction using hydrogen polysaloxane and a platinum metal compound catalyst as main ingredients. Advantageously, the silicone elastomer composition contains a reinforcing filler, such as fumed silica, to increase the film strength.

Here, thermosetting means that the material does not harden at all at room temperature, or even if it hardens, the hardening speed is too slow to be practical, but it hardens rapidly when heated. Moreover, the liquid state may be a solvent-free type, a dispersion type, or a solution type as long as it is liquid at room temperature. In the case of solvent-free type, the viscosity of organopolysiloxane at 25℃ is usually 5000cst.
In the case of a dispersion or solution type, the organopolysiloxane may be in the form of raw rubber or in the form of a liquid.

The cloth may be woven, knitted, nonwoven, or a laminate of these materials, and the material may be cotton, linen, wool,
Any of natural fibers such as silk, semi-synthetic fibers such as rayon and acetate, synthetic fibers such as nylon, polyester, and polyacrylonitrile, and inorganic fibers may be used.

To coat coated paper with a liquid thermosetting addition-reactive silicone elastomer composition, the coated paper is first fixed, and then the liquid thermosetting addition-reactive silicone elastomer composition is coated onto the coated paper. Coating is done by reverse roll coating, wire round bar coating, air knife coating, etc.

Next, cloth is pasted on top of it.
When the silicone elastomer composition is of dispersion or solution type, the organic solvent may be removed to some extent or almost completely before lamination. Further, regardless of whether the silicone elastomer composition is a solvent-free type, a dispersion type, or a solution type, it is preferable to apply the silicone elastomer composition in an uncured or semi-cured state. It is sufficient that the pressure at the time of drawing is at least such that the cloth comes into contact with the thermosetting addition reaction type silicone elastomer composition, and it is preferable that the pressure be applied as uniformly as possible.

The heat curing conditions for the thermosetting addition-reactive silicone elastomer composition include the type and amount of the catalyst used, whether a curing retarder is used, its type and amount, and the composition of the thermosetting addition-reactive silicone elastomer. It varies depending on the thickness of the material layer and the type of fibers that make up the fabric, but generally it is 120℃ to 170℃.
The standard time is 10 to 2 minutes.

Examples of heating methods include hot air drying and infrared irradiation.

After the liquid thermosetting addition-reactive silicone elastomer composition is cured, it is peeled from the coated paper, leaving a fabric coated with a cured silicone elastomer layer. Although the above description has been made regarding coating one side of the cloth, the opposite side may be coated in the same manner after one side is coated.

According to the production method of the present invention, since coated paper is used, even if the coated paper is fixed and the liquid thermosetting addition-reactive silicone elastomer composition coated thereon is heated and cured, polytetrafluorocarbon Unlike films such as ethylene film and polyethylene film, there is almost no thermal expansion, and unlike film, it does not swell with organic solvents, and because it uses coated paper, it has a hardened silicone elastomer layer. The surface of the coated paper is extremely smooth, and the peeling performance of the coated surface against the cured silicone elastomer is less than 50g/cm under the conditions of 25℃, peeling speed of 5m/min, and peeling angle of 180°. , unlike paraffin-coated paper, the silicone elastomer-coated fabric can be peeled off at high speeds of 5-10 m/min without damaging the cured silicone elastomer layer, and it is a liquid thermosetting addition-reactive silicone. Since an elastomer composition is used, the thickness of the silicone elastomer layer can be made extremely thin (for example, 5-100 μm), and the curing speed can be rapid without the generation of voids.The thickness is extremely thin and uniform, and the surface is smooth. Therefore, it is possible to efficiently produce a silicone elastomer-coated cloth having a silicone elastomer layer without voids.

The silicone elastomer-coated fabric produced by the production method of the present invention can be used in clothing such as raincoats, snowwear, anoracks, jogging wear, and diaper covers, industrial materials such as tents and tarpaulins, and medical supplies such as bandages. Can be widely used.

Next, examples of the present invention will be listed. In the examples, "parts" means parts by weight, and all measured values such as viscosity and peel resistance are values at 25°C.
The peel resistance value is the simple average of the values obtained when five test pieces with a width of 5 cm are peeled at a peeling speed of 5 m/min and a peeling angle of 180°.

Example 1 Coated paper in which triacetylcellulose was uniformly coated on glassine paper (thickness of triacetylcellulose
10 μm, glassine paper thickness 210 μm) was fixed using a tenter.

On this coated paper, using an applicator, dimethylsiloxane/methylvinylsiloxane copolymer raw rubber as the main ingredient, liquid methylhydrodiene polysiloxane, platinum catalyst, and reinforcing silica filler are dispersed and dissolved in toluene. An addition reaction type silicone elastomer composition dispersion (solid content 16% by weight, viscosity 6500 cp at 12 rpm using rotor No. 4 using a rotational viscometer) was coated to a thickness of about 200 μm.

Nylon taffeta was laminated on top of it, and toluene was removed by blowing warm air at 40°C. Then 150
The silicone elastomer composition was cured by placing it in a hot air circulating oven at .degree. C. for 5 minutes, and after it was removed from the oven and the temperature reached room temperature, the silicone elastomer-coated nylon taffeta was peeled off from the coated paper at a speed of 5 m/min.

The surface of the cured silicone elastomer layer was extremely smooth, had no scratches or voids, was uniformly cured, and adhered well to the nylon taffeta. The thickness of the cured silicone elastomer layer was 35 μm.

The peel resistance of the coated paper to the cured silicone elastomer was 8.8 g/cm.
Further, even when peeled at a speed of 10 m/min, a silicone elastomer-coated nylon taffeta similar to that described above was obtained.

As a comparative example, instead of the above coated paper,
200μm polytetrafluoroethylene sheet,
An attempt was made to manufacture silicone elastomer-coated nylon taffeta using a 50 μm thick polyethylene film and paraffin-coated glassine paper, with the other conditions being the same as for the resin-coated paper above.
Both had the following drawbacks.

In the case of polytetrafluoroethylene sheet: When placed in the oven, it sagged and the thickness of the cured silicone elastomer layer became uneven. When the surface of the cured silicone elastomer was carefully observed, many fine vertical streaks were present. The peel resistance value of the polytetrafluoroethylene sheet against the cured silicone elastomer was 2.4 g/cm.

In the case of polyethylene terephthalate film: When placed in the oven, it sagged and the thickness of the cured silicone elastomer layer became uneven. It was difficult to peel the silicone elastomer-coated nylon taffeta from the polyethylene terephthalate film, and when I tried to forcefully peel it off, the cured silicone elastomer layer broke. Its peel resistance value was 550 g/cm or more.

In the case of polyethylene film: While the silicone elastomer composition dispersion was being air-dried, the film became uneven. The periphery of the film melted while being placed in the oven. It was completely impossible to peel the silicone elastomer coated nylon taffeta from the film.

In the case of paraffin-coated glassine paper: It was completely impossible to peel the silicone elastomer-coated nylon taffeta from the paraffin-coated glassine paper.

Example 2 Coated paper in which kraft paper was uniformly coated with perfluorooctyl polymethacrylate (thickness of perfluorooctyl polymethacrylate: 5 μm, thickness of kraft paper: 300 μm) was fixed using a tenter.

On top of this coating, use an applicator to apply vinyl-terminated dimethylpolysiloxane (viscosity
1000 cst), methylhydrodiene polysiloxane (viscosity 50 cst), a platinum catalyst and an addition reaction retarder as main ingredients, and a reinforcing silica filler added as a solvent-free thermosetting addition reaction type silicone elastomer composition (as measured using a rotational viscometer). Use rotor No.4,
A coating with a viscosity of 22000 cp at 12 rpm was applied to a thickness of approximately 50 μm.

Laminate polyethylene terephthalate tricot on top of it and place it in a hot air circulation oven at 150℃ for 5 minutes.
The silicone elastomer composition was cured for a few minutes, and after the oven was removed and the temperature reached room temperature, the silicone elastomer-coated polyethylene terephthalate tricot was peeled off from the coated paper at a speed of 5 m/min.

The surface of the cured silicone elastomer layer was extremely smooth, had no scratches or voids, was uniformly cured, and adhered well to the polyethylene terephthalate tricot.
The thickness of the cured silicone elastomer layer was 48 μm.

The peel resistance of the coated paper to the cured silicone elastomer was 15 g/cm.

Example 3 Instead of the triacetylcellulose-coated glassine paper of Example 1, 0.6 parts of trifluorochloroethylene low polymerization product (viscosity 200 cst, n _D 1.409) and 2.5 parts of nitrocellulose were completely dissolved in 50 parts of acetone. An attempt was made to manufacture silicone elastomer-coated nylon taffeta using glassine paper on which the liquid had been uniformly sprayed and the acetone volatilized, but under the same conditions as in Example 1. As in Example 1, a good silicone elastomer was obtained. A coated nylon taffeta could be obtained. The peel resistance value of glassine paper sprayed with nitrocellulose containing trifluorochloroethylene low polymerization degree against cured silicone elastomer is 38
g/cm.

As a comparative example, glassine paper was used which had been uniformly sprayed with a solution in which 0.4 parts of the trifluorochloroethylene low polymerization product and 2.5 parts of nitrocellulose were completely dissolved in 50 parts of acetone to volatilize the acetone. attempted to produce silicone elastomer-coated nylon taffeta under exactly the same conditions as in Example 1. When attempting to peel off the silicone elastomer-coated nylon taffeta from the glassine paper coated with the nitrocellulose containing trifluorochloride ethylene low polymerization product at a speed of 5 m/min, a small dent appeared on the surface of the cured silicone elastomer layer. A slight dent occurred.
When it was torn off at a speed of 0.5 m/min, it remained intact.

In addition, the peel resistance value of the glassine paper coated with the cellulose containing trifluorochloroethylene low polymerization product against the cured silicone elastomer is 58.
g/cm (at a peeling speed of 5 m/min).

Claims (1)

[Claims] 1 Coated paper is coated with a liquid thermosetting addition-reactive silicone elastomer composition, a cloth is laminated on top of the coated paper, the silicone elastomer composition is heated and cured, and then the silicone elastomer-covered cloth is removed from the coated paper. In the method of manufacturing a silicone elastomer-coated cloth by peeling, the peel resistance value of the coated surface of the coated paper to the cured silicone elastomer is determined under the conditions of 25°C, peeling speed of 5 m/min, and peeling angle of 180°. 50g or less/cm
A method for producing a silicone elastomer-coated fabric, characterized in that: