JPH0456064B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to conductive rubber compositions containing reactive silicon groups in polyether. It has already been reported by the present inventors that polyether containing reactive silicon groups at the ends is useful as an elastic sealing material that cures at room temperature. While considering various new applications for this reactive polyether, we discovered that it is possible to easily make a paste by blending and dispersing a conductive filler, and that this paste hardens at room temperature and can be made into any conductive shape. The present invention was achieved by discovering that it is possible to provide a cured rubber product with a high elasticity. That is, the present invention provides (A) at least 1 molecule in one molecule.
The present invention provides a conductive rubber composition containing as active ingredients a polypropylene oxide having a molecular weight of 6,000 to 15,000 and (B) a metal powder. The composition of the present invention has the characteristics that it can be easily made into a paste, hardens at room temperature to give a cured product of any shape, and even if it contains a large amount of metal powder, it does not affect the mechanical properties of the cured product. It has an excellent effect of not causing deterioration. This is presumed to be because the polypropylene oxide of component [A] has a reactive silicon group that can be bonded to the surface of an inorganic substance and has a large molecular weight. In the present invention, the polypropylene oxide which is component (A) must contain at least one reactive silicon group at the end of the molecule or in the side chain. The reactive silicon group has the general formula (Here, X is a hydroxyl group, or a different or the same kind of hydrolyzable group; 3, b is an integer selected from 0, 1 or 2, provided that 1a+b4;R
is a different or similar hydrocarbon group having 1 to 20 carbon atoms; m is an integer selected from 0 to 18) Any group represented by the following may be used. In addition to a hydroxyl group, a hydrolyzable group can also be used as X, but specific examples include a halogen group, a hydride group, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an aminooxy group, an alkenyloxy group, etc. These include, but are not limited to. In particular, the X group is preferably an alkoxy group. The polypropylene oxide used as component (A) essentially has -CH( _CH3 ) _CH2O- as a main chain, but has the formula -R〓-O- (here,
Although R is a divalent organic group, it can also have a chemically bonded repeating unit as shown in (most effective when most of it is a hydrocarbon group having 1 to 4 carbon atoms). Specifically, R〓 is −CH ₂ −, −CH ₂ CH ₂ −,

【formula】

[Formula] −CH ₂ CH ₂ CH ₂ CH ₂ −,

[Formula] etc. The molecular weight of polypropylene oxide is 500-15000
can be effectively used. Polyether containing reactive silicon groups is disclosed in JP-A-Sho.
53-129247, Japanese Patent Publication No. 54-6097, Japanese Patent Publication No. 55-82123,
Unexamined Japanese Patent Publications 1983-123620, 1983-137129, 1983 Unexamined Japanese Patent Publications
−135135, Japanese Patent Publication No. 1983-125121, Special Publication No. 1977-36319,
Special Publication 12154, Special Publication 1971, Special Publication 30711, Special Publication 1977-
36960, etc., but is not limited thereto. In the present invention, metal powders as component (B) include metal powders such as silver, copper, gold, aluminum, nickel, iron, and platinum; particles whose surfaces are plated with these metals are effectively used, but are limited to these. It is not something that will be done. These metal powders can be used in any amount depending on the purpose, but (A) component polyether
It is preferable to use it in an amount of 1 to 300 parts by weight, preferably 10 to 200 parts by weight per 100 parts by weight. In the present invention, instead of metal powder, carbon black such as thermal black, furnace black, lamp black, channel black, roll black, disk black, acetylene black (particularly cheap and conductive), carbon fiber, metal transition black, etc. It is also possible to use, in this case, it has excellent mechanical properties. However, although metal powder having a large specific gravity and no reinforcing effect is used, the composition of the present invention provides a cured product having excellent mechanical properties. In the present invention, both components (A) and (B) are contained as active ingredients, but various additives may be added to accelerate curing or improve the properties of the cured product.
It also includes the use of modifiers, curing catalysts, reinforcing agents, fillers, etc. in combination. For example, silanol condensation catalysts can be used in conjunction to accelerate curing;
Alkyl titanates, if used; organosilicon titanates; metal salts of carboxylic acids such as tin octylate, dibutyltin dilaurate, dibutyltin maleate, etc.; amine salts such as dibutylamine-2-ethylhexoate; Known silanol condensation catalysts such as other acidic catalysts and basic catalysts can be effectively used. In the present invention, various plasticizers can be effectively used in combination in order to incorporate a large amount of filler. In order to improve adhesiveness, phenolic resins, epoxy resins, modified rosins, terpene resins, reactive silicone compounds (see, for example, Japanese Patent Application Laid-open No. 129247/1983), etc. can be used. Also 1,2-polybutadiene,
Modified and unmodified polymers (especially liquid polymers) such as 1,4-polybutadiene, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, polyisobutylene, polyester, polyisoprene, and polysiloxane are used to cure water-resistant machines. It also includes the use in combination to improve characteristics. It also includes the addition of various additives such as anti-aging agents and ultraviolet absorbers. The composition of the present invention can be used as a curable conductive rubber composition for adhesives, paints, sealants, corona discharge prevention materials, radio/electromagnetic shielding materials, gaskets, electrodes, surface heating elements, anti-static products, and various conductive materials. Rubber molded products, electronic parts (connectors, switches)
It can be effectively used as a one-liquid type or a two-liquid type. Examples will be specifically described below. Reference Example 1 800 g of polypropylene oxide (manufactured using polypropylene glycol as a starting material) with an average molecular weight of 8000 containing 97% allyl ether groups at the terminals was placed in a pressure-resistant reaction vessel equipped with a stirrer, and methyldimethoxysilane was added. 15 g, followed by a catalyst solution of chloroplatinic acid (H ₂ PtCl ₆ .
6H ₂ O 8.9g and isopropyl alcohol 18ml,
solution in 160ml of tetrahydrofuran) 0.34
ml was added, and the mixture was reacted at 80°C for 6 hours. As a result of quantifying the residual hydrosyl group from the IR spectrum,
I can see that it's mostly responsive,

A polypropylene oxide terminated with the group [Formula] was obtained. Reference Example 2 800 g of polypropylene oxide with an average molecular weight of 8000 containing 97% allyl ether groups at the terminals was placed in a pressure-resistant reaction vessel equipped with a stirrer.

Add 60 g of a silicon hydride compound having the structure of [Formula], then add 0.34 ml of a catalyst solution of chloroplatinic acid (see Reference Example 1), and heat at 80°C for 60 g.
Allowed time to react. IR analysis shows that there is no residual hydrosilyl group at the end. It was found that polypropylene oxide having groups was obtained. Reference Example 3 600 g of polypropylene oxide with an average molecular weight of 6000 containing 96% of allyl ether groups at the ends was placed in a pressure-resistant reaction vessel equipped with a stirrer.

27 g of a silicon hydride compound having the structure of [Formula] was added, followed by 0.34 ml of a chloroplatinic acid catalyst solution (see Reference Example 1), and the mixture was reacted at 80° C. for 6 hours. Thereafter, 500 ml of toluene was added, further 18 g of triethylamine was added, and 4 g of water was added dropwise while stirring while maintaining the temperature at 30°C. Hydrolysis was carried out by stirring at 40°C for 3 hours. The generated triethylamine hydrochloride was separated and toluene etc. was distilled off at 60℃ under reduced pressure.

A polypropylene oxide having the structure of [Formula] at the end was obtained. Reference example 4 800g of polypropylene oxide with a molecular weight of 4000,
A polypropylene oxide having reactive silicon groups was obtained in the same manner as in Reference Example 1, except that 31 g of methyldimethoxysilane was used. Comparative Example 1 2,2'- for 100 parts by weight of the polymer of Reference Example 1
Take 1 part by weight of methylene-bis-(4-methyl-6-ter-butylphenol) and 30 parts by weight of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd., powder), mix by hand, and mix well with three paint rolls. Mix. Further, 3 parts by weight of tin octylate and 1 part by weight of laurylamine are added and mixed thoroughly to obtain a room temperature curable paste. A sheet with a thickness of about 2 mm is prepared from the paste and cured at room temperature for 7 days and then at 50°C for 7 days. A test piece was taken from the sheet and its volume resistivity was measured and found to be 2×10 ³ Ω·cm. Further, when the tensile properties of this sheet were measured, the strength at break was 9.2 Kg/cm ² and the elongation at break was 310%. Comparative Example 2 A cured rubber sheet is prepared in the same manner as in Example 1 except that 100 parts by weight of the polymer of Reference Example 2 is used instead of the polymer of Reference Example 1. The volume resistivity value of the cured rubber sheet is 5×10 ³
It was Ω・cm. Comparative Example 3 For 100 parts by weight of the polymer of Reference Example 3, 2,
1 part by weight of 2'-methylene-bis-(4-methyl-6-ter-butylphenol), 8 parts by weight of ethyl silicade
Parts by weight, acetylene black (Denki Kagaku Kogyo Co., Ltd.)
After hand-kneading 35 parts by weight of powdered powder, mix well with three paint rolls. Further, 3 parts by weight of dibutyltin dilaurate and 3 parts by weight of activated zinc white are added and mixed well to obtain a paste that hardens at room temperature. A sheet with a thickness of about 2 mm is prepared from the paste and cured at room temperature for 7 days and then at 50°C for 7 days.
A test piece was taken from the sheet and the specific volume resistivity was measured to be 1×10 ³ Ω·cm. Example 1 A cured rubber sheet was prepared in the same manner as in Comparative Example 1 except that 70 parts by weight of silver powder was used instead of acetylene black. The volume resistivity value of the cured rubber sheet is 2×10 ^-1
It was Ω・cm. Further, when the tensile properties of this sheet were measured, the strength at break was 7.2 Kg/cm ² and the elongation at break was 260%.
When compared with the results of Comparative Example 1, it can be seen that despite the use of metals with low interaction with organic matter, there is no deterioration in mechanical properties and the specific volume resistivity is also small. Comparative Example 4 A cured rubber sheet was prepared in the same manner as in Comparative Example 1, except that the polymer of Reference Example 4 was used instead of the polymer of Reference Example 1, and 70 parts by weight of silver powder was used instead of acetylene black. Create.
The tensile properties of the cured rubber sheet are strength at break of 3.6
Kg/cm ² and elongation at break was 30%. This comparative example differs from Example 1 in that the molecular weight of component [A] is smaller, but it can be seen that the mechanical properties are inferior.

Claims (1)

[Scope of Claims] 1. A conductive material containing as active ingredients [A] polypropylene oxide with a molecular weight of 6,000 to 15,000 and having at least one reactive silicon group in one molecule, and [B] metal powder. rubber composition. 2. The conductive rubber composition according to claim 1, wherein the reactive silicon group is an alkoxysilyl group.