JPS5889351A - Manufacture of independent cellular silicone rubber utilizing silk screen printing method - Google Patents

Abstract

PURPOSE:To reduce the amount of silicone rubber to be used, by a method wherein a capsule, in which low-boiling hydrocarbon is encasulated in a vinylidene chloride copolymer shell, is mixed in silicone rubber, and a silk screen printing is performed using the mixture. CONSTITUTION:A capsule foaming agent, in which a low-boiling hydrocarbon is encapsulated in a shell formed of a vinylidene chloride copolymer with a grain size of 10-30mum, is prepared. Said capsule foaming agent is a heat-vulcanizing silicone rubber or a normal temperature-vulcanizing type, and 1.0-20pts.wt., based on 100pts.wt. silicone rubber, of said capsule is mixed in silicone rubber. After a required shape is silk screen-printed on a supporter using the mixture, the object being printed on the supporter is heat-processed at a temperature range of 50-150 deg.C for 1-20min to obtain an independent cellular silicone rubber elastic product.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a silk screen printing method to produce a closed-cell silicone rubber elastomer. Regarding the method.

In general, silicone rubber elastic bodies have superior heat resistance, chemical resistance, weather resistance, etc. compared to other rubber elastic bodies.
It is also widely used for backings, gaskets, etc.

However, when manufacturing armrests or gaskets using silicone rubber elastic material, the conventional method has been to prepare a sheet-like silicone rubber elastic material with a predetermined thickness and punch this sheet into the desired shape. Therefore, there was a drawback that there was a waste of kana on the sheet.

The present inventors have focused on the fact that unvulcanized or uncured silicone rubber has a tack that can be used for silk screen printing, and the silicone rubber that has been printed into a desired shape using the silk screen printing method.

If this is simply vulcanized or hardened, it will not be thick enough to be used as a notching or gasket.
If the foam is made to have a closed cell structure instead of an open cell structure,
It has been found that a closed-cell silicone rubber elastic body that can be used for backings or gaskets can be obtained without wasting silicone rubber because the thickness required for backings or gaskets can be obtained.

Therefore, the method of the present invention has a heat-vulcanized silicone rubber or a room-temperature vulcanizable silicone rubber with a grain size in the range H of 10 to 30 μm, and a low-temperature vulcanized silicone rubber in a shell formed of a vinyl chloride y copolymer. A capsule blowing agent containing a boiling point hydrocarbon is mixed at a ratio of 1.0 to 20 parts by weight per 100 parts by weight of silicone rubber, and a desired shape is printed on a support using this mixture using a silk screen IJ-printing method. 9 Then, the printed material on the support was heated at a temperature range of 50 to 150°C for 1 to 20°C.
It consists of a heat treatment for a minute and foaming.

In the present invention, both heat vulcanization type and room temperature vulcanization type silicone rubber can be used.

Heat-curable silicone rubbers include dimethyl silicone rubber, methylphenyl silicone rubber, methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber,
There is methylfluorozolobyl silicone rubber. Dimethyl silicone rubber is a 4/f dimethyl silicone rubber, but methyl vinyl silicone rubber has some of the methyl groups replaced with vinyl groups, can be vulcanized in hot air at normal pressure, and has poor physical properties such as compression set. superior to dimethyl silicone rubber. Furthermore, silicone rubber containing phenyl groups has excellent low-temperature properties, and silicone rubber containing fluoropropyl groups has good solvent resistance. Therefore.

It is preferable to select the type of silicone rubber used as a raw material depending on the purpose of use of the closed-cell rubber elastic body finally obtained.

Heat-curable silicone rubber can be vulcanized using organic peroxides, fatty acid azo compounds, sulfur, radiation, etc. The most common vulcanizing agents are organic peroxides, and specific examples include Benzoyl oxide, male peroxide 2', 4-dichlorobenzoyl, dicumyl peroxide, ditertiary peroxide
Butyl and the like can be given as an example. These vulcanizing agents,
It is possible to adjust the blending amount to the silicone rubber within the range of Fil to lO weight.

As the room temperature vulcanizable (RTV) silicone rubber, both one-component type and two-component type can be used. One-liquid type RTV silicone rubber consists of diorganopolysiloxane having a hydroxyl group at the end and a crosslinking agent.

It is mainly cured by a condensation reaction with moisture in the air, and the crosslinking agents in this case include methyltriacetoxysilane, ethyltriacetoxysilane (acetic acid removal condensation type), acetone oxime silane, butanone oxime silane (above). Oxime decondensation type], methyltrimethoxysilane, vinyltrimethoxysilane (dealcoholization condensation type), silazane (acetic acid decondensation type), etc.On the other hand, two-component RTV silicone rubber has functional terminals. The three components of diorganopolysiloxane having a group, a crosslinking agent, and a curing catalyst are divided into two parts, and two-part RTV silicone rubber is divided into two types based on the curing mechanism. One of them is metal organic acid salts, organic amines, quaternary ammonium or phosphonium compounds as t-curing catalysts.
This type is cured by dealcoholization condensation between silanol and alkoxysiloxane (alkyl orthosilicate), dehydration condensation between silanols, and dehydrogenation condensation between silylidyl (-1! IIH) and silanol. This type cures by addition polymerization of vinyl groups and 18iH using a curing catalyst such as nogradium, platinum, or peroxide, and when this mixture is heated to 60 to 150°C, the fruit bridge reaction occurs rapidly. It is a preferred two-component type RTV silicone rubber because it cures as it progresses and its crosslinking temperature matches the foaming temperature of the capsule foaming agent described later.

The capsule blowing agent used in the present invention is vinylisochloride/
A low-boiling hydrocarbon such as butanepentane is encapsulated in a shell formed of a copolymer, and the particle size can be in the range of 10 to 30 μm. This type of capsule foaming agent mixes uniformly with the silicone rubber mentioned above! Not only can it pass through a silk screen with a mesh size of 300 or more, it can also form closed cells because the shell does not break during foaming. A specific example of a capsule foaming agent that can be used in the present invention is a microcapsule commercially available as Taden Kuro, e-le F-30 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.), and the physical properties of this product include particle size. 10-30 μm.

The specific gravity is 1.13 g/Cfn'', the softening source is 80-85°C, and the maximum expansion ratio is 70 times.

According to the present invention, Capsule Foaming Agent Silicone Rubber 10
0 parts by weight Roaring 1. Mix 0 to 20 parts by weight.

When 20 parts by weight or more are mixed, the final silicate;
This is because the physical properties of the rubber elastic body are impaired.

Mixture of capsule blowing agent and silicone rubber.

Treated as an ink equivalent for silk screen printing,
This is used to silk screen print a desired shape onto any support. The mesh size of the silk screen used for printing is 48 to 30 to ensure the precision of the printing pattern.
ft- is allowed for about 0 meshes. The printed pattern on the support is then heat treated at a temperature range H of 50 to 150 DEG C. for about 1 to 20 minutes.

This allows the capsule foaming agent to foam into a closed cell structure and harden the silicone rubber! ! II. A foamable silicone rubber elastomer can be obtained.

In the present invention, filler material, flaring material, and other additives may be used in combination as necessary. This type of filler includes fine silica powder such as foamed silica, which is used for reinforcement purposes, and ±0 silica powder, which is used primarily to increase the volume.
Quartz powder, calcium carbonate.

Clay, alumina 2. Iron oxide - titanium oxide, carn black, etc. Among these, Ill pig iron titanium oxide, casen black, etc. are also used as pigments. Additives include silicone resins, alkoxine diamines, siloxanes, hydroxysilanes, and siloxanes, which are used as dispersion promoters when made silica is used as a filler. Dimethyl silicone oil is preferably used for this purpose.

Example 1 To 100 g of 5H-433 (heat-curable silicone rubber) manufactured by Toray Silicone Co., Ltd., the aforementioned Micro/9-L F-30 (capsule blowing agent) sgt- was added, mixed well, and then vulcanized. 10g ditert-butyl peroxide as agent
f: Mix and use this uniform mixture and a 60-mesh silk screen to form the tooth plane shape (11") shown in the attached drawing.
” 2.5 mm, r@-wi, off1m.

A 0.5 mm thick turn was printed on release paper. Then / on the release paper
When foaming was performed by heat treatment in an oven at 130° C. for 15 minutes, a closed-cell silicone rubber elastic body having an average thickness of g and 5 ff 1 m was obtained.

There is no dimensional distortion in the printed pattern after foaming.

It showed high elasticity only in the thickness direction.

Example 2 8H-780 (1-component RT) manufactured by Toray Silicone Co., Ltd.
V silicone rubber) was mixed well with 2.5 g of Micropearl F-301, and using this mixture and an 80 mesh silk screen, the radius was 30 mm in a nitrogen gas atmosphere containing no moisture vr.

It was printed on a circular, 41 turn T aluminum foil with a thickness of Q, lt nm. Next, heat treatment was performed on the aluminum foil in an oven at 140°C for 1 minute to foam, and then the foam layer was left in a room at a temperature of 5°C and a humidity of f3Q%RH, and there was no collapse of the foam layer. It hardened to the touch after 45 minutes, and completely hardened after 4 hours, yielding a closed-cell silicone rubber elastic body with a thickness of 3 mm.

Since this rubber elastic body has a closed cell structure, it has a high compressive elastic modulus and also has 1.0% liquid leakage. It is suitable as a seat backing because it does not cause any gas leakage.

Example 3 100 g of 8E-1yoo (two-component LTV silicone rubber) manufactured by Toray Silicone Co., Ltd. was thoroughly mixed with 5 g of Micropearl F-30, and this mixture was coated with a 200-mesh silk screen to a thickness of 0. Half 1150mm, length 15attn on a .3mm iron plate.

Printed a ring-shaped pattern of rhinoceros QJm+n nine days later.

A closed-cell silicone rubber elastic body having a thickness of 0.6 mm was obtained by heat treatment at 140° C. for 10 minutes.

When this iron plate with the ring-shaped silicone rubber elastic body attached was pressure-molded so that the silicone rubber elastic body was on the inside and used as a cap for a glass container, this thing did not get wet and completely prevented liquid from leaking. 9. Demonstrates sealing effect.

Example 4 8H-9583 (2-liquid WR) manufactured by Toray Silicone Co., Ltd.
TV silicone rubber) 4g of ζ chrono on loog
Mix well and use this mixture with a 60-mesh silk screen to measure the diameter of 0. ! Small dots with a width of 2 mm between Imm and f and a thickness of 9.2 mm were printed on the entire surface of Tetron woven fabric, and then heat treated and foamed at t-100°C for 10 minutes, resulting in a thickness of 0.5 to Q, 15 mm.
A cloth having dots of closed-cell silicone rubber elastic material was obtained. This material has a large coefficient of friction and can withstand per-clean and tri-clean.

It also has excellent iron resistance, so it can be used to prevent slippage on belts, the waist of jeans, and shoulder straps.

[Brief explanation of drawings]

The attached drawing is a plan view of the nine printing patterns obtained by silk screen printing of Example 1.

Claims (1)

[Claims] 1. Heat-vulcanized silicone rubber or room-temperature vulcanized silicone rubber has a zero particle size in the range of 10 to 30 μm, is made of vinyl chloride y copolymer, and has low-boiling hydrocarbons encapsulated in its shell. Add the capsule foaming agent to the silicone rubber 1
A desired shape is silk screen printed on a support using this mixture, and the printed material is heated at a temperature of 50 to 150°C. A method for producing a closed-cell silicone rubber elastomer, which comprises foaming by heat treatment within a range of 1 to 20 minutes.