JPS5825327B2 - Koukasei Gomuso Seibutsu - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a curable rubber composition particularly useful as a casting or impregnating rubber, and its main objects are to improve electrical properties, thermal properties, mechanical properties, In particular, it is an object of the present invention to provide a composition from which a cured product with excellent extensibility and adhesiveness can be obtained.

It is already well known to use a curable rubber composition by injecting it into a mold or impregnating it into an insulating layer of an electric winding and curing it.

Polyester/polyether polyurethane, polybutadiene polyurethane, etc. are used for such purposes, but the former has the disadvantage of poor electrical properties and heat deterioration resistance, while the latter has the disadvantage of poor elongation and adhesive properties. Therefore, it is desired to develop a material with excellent electrical properties, heat deterioration resistance, and mechanical properties, especially extensibility and adhesive properties.

In view of the current state of conventional curable rubber compositions, we conducted intensive studies to develop a new curable rubber composition, and as a result, we discovered a highly effective curable rubber composition and arrived at the present invention.

That is, conventional urethane rubber mainly composed of 1.4 polybutadiene diglycol has the best physical properties among liquid rubbers, and is being put into practical use as a rubber comparable to solid rubbers.

However, although unsaturated bonds contained in molecules contribute to physical properties at low temperatures, they are susceptible to oxidation and
It is in a state where it cannot withstand the above continuous use.

In addition, as a method for renovating these drawbacks, conversion to a saturated hydrocarbon system by hydrogenation is a known means.

However, when 1,4-polybutadiene diglycol is hydrogenated, it becomes crystalline, which not only makes compatibility and mixing operations of other additives extremely difficult,
The properties of urethane rubber that have reacted with incyanate tend to deteriorate overall, and in particular become inferior in terms of adhesion.

For this reason, its use as a filler or integrally cast product for electrical equipment, where resistance to deterioration and adhesiveness are important, has been limited.

The present inventors investigated a method of imparting plasticity to the molecule and improving adhesiveness while retaining the characteristics of the hydrogenated 1,4-polybutadiene glycol, and found that polybutadiene glycol is preferable in terms of compatibility. , and a hydrogenated product of 1,2-polybutadiene glycol was found to improve adhesive strength the most.

That is, the characteristics of the present invention are that (a) the polyisocyanate compound has (b) two or more hydroxyl groups per molecule, and there are 6 butadiene residues consisting of 1.4 bonds in the polymer chain.
Hydrogenated product of butadiene liquid polymer present at 0% by weight or more (
Hereinafter, it will be abbreviated as hydrogenated 1.4PB.

) (C) Hydrogenated butadiene liquid polymer having one or more hydroxyl groups per molecule and containing 70% by weight or more of butadiene residues consisting of 1.2 bonds in the polymer chain (hereinafter referred to as hydrogenated 1.2 bonds).
2PB).

According to the present invention, it is possible to obtain a cured product that has superior adhesion to metals, ethylene propylene rubber, butyl rubber, etc. compared to conventional products.

Further, the cured product of the present invention has excellent electrical properties and heat deterioration resistance.

Further, according to the present invention, a cured product with excellent mechanical properties can be obtained. Examples of incyanate compounds useful in the present invention include fenene diisocyanate, tolylene diisocyanate,
Examples include diphenylmethane diisocyanate, diphenyl ether diisocyanate, naphthalene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate.

Examples of hydrogenated 1.4PB useful in the present invention include ARCO
POIYBD, R-45M, R-45HC8-
15 etc. can be obtained by hydrogenation using a catalyst such as a Raney catalyst or a stabilized nickel catalyst.

Hydrogenated 1.4PB preferably has a hydrogenation rate of 50% or more.

Examples of hydrogenated 1.2PB useful in the present invention include Nippon Soda NI S 80 PBG-1000 and PBG-2.
000, PBG-3000, etc. can be obtained by hydrogenating using the catalyst described above.

Further, the hydrogenated 1.2PB preferably has a hydrogenation rate of 50% or more.

In particular, the reaction accelerator used in the present invention includes tertiary amines,
Examples of 8th class amines for which organometallic compounds are effective include triethylenediamine, triethylamine, dimethylamine ethanol, and N-methylmorpholine; examples of organometallic compounds include dibutyltin dilaurate and dimethyltin diacetate. There is.

The mixing ratio of hydrogenated 1.4PB and hydrogenated 1.2PB used in the present invention is hydrogenated 1.2PB to 100 parts of hydrogenated 1.4PB.
P810-300 parts, preferably 30-200 parts is optimum.

Outside the above range, the adhesive strength decreases.

Further, it is preferable to mix 0.9 to 1.2 equivalents of the incyanate compound to 1 equivalent of the hydrogenated 1.4PB and hydrogenated 1.2PB mixture.

Outside these ranges, adhesiveness decreases.

Fillers and reinforcing agents used in the present invention include calcium carbonate, silica, alumina, hydrated alumina, clay, talc, mica, carbon black, etc., and any of these can be used effectively depending on the purpose. .

The present invention will be explained in detail below using reference examples, working examples, and comparative examples.

The tensile strength elongation in Examples and Comparative Examples is JIS-63.
According to 01, the peel adhesion strength is ASTM-D1876-6.
9.

Further, the electrical characteristics were determined according to JIS-6911.

Reference example 1 POIYBDR-45M (butadiene liquid polymer)
Manufactured by ARCO 1,1.4-trans 60%, 1.4-cis 20%, 1.2-vinyl 20%, OH value 53) 120
g, 10 g of Raney nickel catalyst and 1 dioxane
00g into 11 autoclave and hydrogen pressure 100kg
/cI? L. Reduction reaction was carried out at a reaction temperature of 80° C. to obtain a hydrogenated product of butadiene liquid polymer (hydrogenation rate 95%).

Reference Example 2 POIYBDC8-15 (butadiene liquid polymer)
Manufactured by ARCO, 60% 1.4-trans, 20% 1.4-cis, 20% 1.2-vinyl, copolymer of butadiene and styrene with a butadiene to styrene ratio of 75:25, OH
52) was subjected to a reduction reaction in the same manner as in Reference Example 1 to obtain a hydrogenated product of butadiene liquid polymer (hydrogenation rate 98%).

Reference example 3 Nl5SOPBG-200 which is a butadiene liquid polymer
0 (manufactured by Nippon Soda, 1.2 vinyl 90%, 1.4 bond 10
%, OH value 58) was subjected to a reduction reaction in the same manner as in Reference Example 1 to obtain a hydrogenated product of butadiene liquid polymer (hydrogenation rate 98%).

Example 1 50 g of hydrogenated 1.4PB obtained in Reference Example 1 and 50 g of hydrogenated 1.2PB obtained in Reference Example 3 were mixed with 8.0 g of toluene diisocyanate.
Add 7g and mix, then pour into a polypropylene mold 1
It was cured at 20°C for 8 hours.

The properties of this cured product are as follows, and are superior in elongation, electrical properties, and heat deterioration resistance compared to conventional products.

Initial value Value after 15 days at 100°C Tensile strength (kii) 50 72 Elongation (%
) 625 470 tanδ (%) 1,81 1.65
ε2.70 2.70 Pv (ΩcrrL) 5.0X10 5.5X1
Example 2 To 860 g of hydrogenated 1.4P obtained in Reference Example 1 and 40 g of hydrogenated 1.2PB obtained in Reference Example 3, 12.5 g of diphenylmethane diisocyanate and 0.05 g of dibutyltin dilaurate were added and mixed.

A portion of this mixture was applied to a 100μ thick steel plate, two sheets were stacked together and pressed together with a roll, and then
'CX Cured in 1 hour.

The peel adhesion strength of the steel plate thus obtained was 7 at room temperature.
．． 2 kg/crrL, and has very good adhesiveness.

Example 3 To 40 g of hydrogenated 1.4PB obtained in Reference Example 1 and 860 g of hydrogenated 1.2P obtained in Reference Example 3, 8.4 g of hexamethylene diisocyanate and 0.05 g of dibutyltin dilaurate were added and mixed.

A portion of this mixture was applied to a 100 μm thick ethylene propylene rubber sheet, two sheets were stacked together and pressed together with a roll, and then cured at 180° C. for 2 hours.

The peeling adhesive strength of the ethylene propylene rubber sheet thus obtained was 3.7 kg/cm at room temperature, indicating very excellent adhesiveness.

Example 4 50 g of hydrogenated 1.4PB obtained in Reference Example 1, 50 g of hydrogenated 1.2PB obtained in Reference Example 3, and 1 naphthalene diisocyanate
Add 0.5g11-lyethylenediamine 0.1g and mix.

A portion of this mixture was applied to a 3 cfn butyl rubber sheet to a thickness of 100 μm, the two sheets were stacked together, pressed together with a roll, and then cured at 180° C. for 2 hours.

The peel adhesion strength of the butyl rubber sheet thus obtained was 4.7 kg/cIIL at room temperature, indicating very excellent adhesion.

Examples 5 to 8 Hydrogenated 1.4PB obtained in Reference Example 2 and Hydrogenated 1B obtained in Reference Example 3
．． 2PB was mixed with diphenylmethane diisocyanate at different mixing ratios, applied to a 200μ thick steel plate to a thickness of 100μ, laminated and crimped with a roll, and then
It was cured at 0°C for 2 hours.

The adhesive strength of the cured product was as shown in the table below.

In order to clarify the effect of changing the mixing ratio of hydrogenated 1.4PB and hydrogenated 1.2PB, the properties of the cured product were compared when hydrogenated 1.2PB was not added and when a large amount of hydrogenated 1.2PB was added.

Comparative Example 1 100 g of hydrogenated 1.4PB obtained in Reference Example 2, 12.5 g of diphenylmethane diisocyanate, and 0.05 g of dibutyltin dilaurate were mixed to obtain a cured product in the same manner as in Example 5.

Comparative Example 2 100 g of hydrogenated 1.4PB obtained in Reference Example 2, 350 g of hydrogenated 1.2PB obtained in Reference Example 3, dibutyltin dilaure-1-
A cured product was obtained in the same manner as in Example 5.

Claims (1)

[Claims] 1. Hydrogenated butadiene liquid polymer having two or more hydroxyl groups per molecule and 60% by weight or more of butadiene residues consisting of 1.4 bonds in the polymer chain in a polyisocyanate compound and per molecule 70% by weight of butadiene residues with one or more hydroxyl groups and 1.2 bonds in the polymer chain
A curable rubber composition characterized by being blended with a hydrogenated product of the butadiene liquid polymer as described above.