JPS61141757A - silicone rubber composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a silicone rubber composition, particularly a silicone rubber composition obtained by blending two or more silicone rubber materials without disadvantages such as delamination phenomena. It is related to.

(Conventional technology) Silicone rubber has heat resistance, cold resistance, chemical resistance, weather resistance,
It is used in a wide variety of applications because it has better solvent resistance than other synthetic rubbers and natural rubbers, but with the diversification of applications, rubber with higher properties has become available. requested. Therefore -722A4-4'3.3.3
Although products in which a -trifluoroglobyl group or the like is introduced into the side chain have also been developed, all of these have the disadvantage of being expensive.

Therefore, attempts have been made to modify silicone rubber by blending two or more organopolysiloxanes with different chemical structural formulas to obtain a composition that takes advantage of the strengths of each, and by changing the blend ratio. In this case, compatibility is important, although products with various properties can be easily and economically advantageously obtained.

Since it is a blend of two or more organopolysiloxanes with different reactivities, the molded product obtained by vulcanization peels off in a thin layer. A serious drawback arises in that a so-called delamination phenomenon occurs. and.

Molded products with this phenomenon do not pose much of a problem in static applications such as backing, but should not be used in applications such as seals on sliding parts that are subject to dynamic stress, as there is a risk of accidents. The disadvantage of not being able to do this is to counter this problem by adjusting the curing speed between different types of materials, or by tightening the mixing conditions in the blend ratio to uniformly mix and disperse these materials. A satisfactory solution has not yet been reached.

(Structure of the Invention) The present invention relates to a blend type silicone rubber composition that solves the above-mentioned disadvantages.
R is the same or different unsubstituted or substituted monovalent hydrocarbon group, a and b are a≧0. b>0.1.95<a+b<2.0
The organopolysiloxane represented by the general formula 0 (%) is the same or different type of unsubstituted or substituted monovalent hydrocarbon group (
However, −R is different from R1, R1, and R3 (σJ), C
, (l is C20, d>0.1.95<o+d<2.05
100 parts by weight of a mixture with an organopolysiloxane represented by a positive number],
R'', R' are the same as above, e, f+g+h<4
An organopolysiloxane expressed as a positive number 0.
1 to 100 parts by weight, 2) Fine powder silica filler 5 to 200 parts by weight
It is characterized by consisting of:

Namely, the present inventors conducted various studies on methods for solving the delamination phenomenon in silicone rubber molded products obtained from silicone rubber compositions made by blending different types of organopolysiloxanes, and found that When an organopolysiloxane containing at least one organosiloxane unit contained in each organopolysiloxane used as a raw material is added, this organopolysiloxane becomes an organosiloxane that is the same as the organopolysiloxane used as a blend material. unit, the presence of this organopolysiloxane alleviates the incompatibility between the organopolysiloxanes used as materials, and the molded product is free from the delamination phenomenon. The present invention was completed by conducting research on the type of organopolysiloxane material, the type of organopolysiloxane added to the material, its manufacturing method, and the blending amount thereof.

The organopolysiloxane as the a) component constituting the composition of the present invention is 1. It is represented by the general formula % (%), where R' and R'' are an alkyl group such as a methyl group, an ethyl group, a tetravir group, a butyl group, or a vinyl group.

alkenyl groups such as allyl groups, aryl groups such as phenyl groups and tolyl groups, cycloalkyl groups such as cyclohexyl groups, or some or all of the hydrogen atoms bonded to the carbon atoms of these groups). a≧O, b>0
．． It is considered to be a positive number of 1.95<a+b<2.05, but since it is a rubber material, it is preferable to have a substantially linear structure, and the end thereof is It may be a silanol group, a dolorganosilyl group, etc., and K is not limited to 4IK. Another invention σ)
The composition is cured to form a rubber-like elastic body.

This R
3. 0.025 to 1O of the monovalent hydrocarbon group represented by R1
Preferably, the mole percent is unsaturated groups such as vinyl groups.

In addition, the organopolysiloxane as the above component is represented by the general formula, and Ra -R4 is an unsubstituted or substituted monovalent hydrocarbon group of the same kind or number having the same polarity as the above-mentioned R2 and R1, c -d is C10, d>0.1.95<c+d<
Although it is assumed to be a positive number of 2.05, it is preferable that it has a substantially K11-like structure as in component (a); there are no particular restrictions on its terminal group either.

Further, it is preferable that 0.025 to 10 mol% of R and R are unsaturated groups, however, R, R・σ]
Of these, RK is the R mentioned above.

It may be the same group as R'', but for this RK, R,
Furthermore, K is required to be σJ, which is different from RR.

Next, the organopolysiloxane as component c) constituting the composition of the present invention is represented by the general formula, where R1, RN, RN, and R4 are the same or different monovalent hydrocarbon groups as described above.

s, f, g, h are e≧0. f>O, g≧0. 13. It is a positive number where h>0 and O<e + f + g + h < 4. This is also preferably a substantially linear structure. However, since the organopolysiloxane as component c) is added to prevent the delamination phenomenon of the organopolysiloxane blend product as component 1) described above,
), it is necessary to contain at least one organosiloxane unit constituting the organopolysiloxane represented by formula 23.

The organopolysiloxane represented by the formula (3) may be produced by cocondensation polymerization of organosilanes containing monovalent hydrocarbon groups represented by R1, RR, R11, and R4; It may also be a block copolymer of organopolysiloxane shown in 2), and this block copolymer is produced by reacting a lithium compound with an organopolysiloxane end-blocked with a hydroxyl group, and then reacting this with another type of organopolysiloxane. A method of reacting siloxanes (see U.S. Pat. No. 3,337,497), a method of joining two organopolysiloxanes with a highly active silane or siloxane such as acinosilane, oxime silane, etc.

MK can be obtained by a method in which a trimer of each monomer based on chlorosilane or chlorocyclohexane is ring-opened in hexamethylphosphontrioxide (HMPA) and hydrolyzed.

The block copolymer thus obtained may be used as a base polymer for silicone rubber if it is a polymer, or it may be used as a mere additive. Further, the terminal group of this product may be a silanol group that is still condensed or hydrolyzed, but these are treated with dirane or the like and blocked with a trimethylsilyl group, a vinyldimethylsilyl group, etc. There may be. but,
This is because multiblock is better than monoblock from the purpose of preventing delamination, and there are also non-containing groups such as vinyl groups in the molecule that can be used as crosslinking points with the mixture of components that become the base polymer. It is preferable to include a saturated group. In addition.

The blending amount of this Han ingredient is a) 1 mouthful] mixture of ingredients 100
If it is less than 0.1 part by weight, the effect is not sufficient (but if it is more than 100 parts by weight, the effect on the physical properties of the cured product obtained from this composition becomes large, and the cured product does not have sufficient properties. Therefore, it is necessary to set the amount in the range of 0.1 to 100 parts by weight (G), but it is preferably in the range of 0.5 to 10 parts by weight. .

The silica filler used as the second component may be any one known for use in silicone rubber compositions.

Examples of this include hiemed silica, precipitated silica-quartz powder, and hiemed silica surface-treated with hexamethyldisilazane, dimethyldichlorosilane, octamethylschifftetrasiloxane, etc.
If this amount is less than 5 parts by weight based on 100 parts by weight of the mixture of the above-mentioned a)-rono component, the cured elastic body obtained from this composition will have poor mechanical strength, and if it is 200 parts by weight or more, a good quality rubber will be obtained. 5 because it will not be possible to obtain an elastic body.
-200 parts by weight, preferably 50-150 parts by weight.

The silicone rubber composition of the present invention can be obtained by uniformly mixing the above-mentioned components (a) to (ii). This mixing may be carried out by the cross-mixing method normally used in the manufacture of silicone rubber, especially a two-roll or Doug mixer.

There is no need to create elaborate cross-talk using Nei-Goo. In the production of this silicone rubber composition, it is optional to add the above-mentioned ingredients such as silicone oil and other polymers in the form of crude rubber. Even if you add fillers such as soil, calcium carbonate-mica, clay, aluminum hydroxide, heat resistance improvers, colorants, cerium monide, cerium hydroxide, iron oxide, carbon black, etc. good.

Further, the silicone rubber composition may be cured by a conventional curing method used for silicone rubber. That is, for this curing, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, p
-Chlorobenzoyl peroxide.

Di-t-butyl peroxide, dicumyl peroxide, t-butyl perbenzoate, 2,5-dimethyl-
2,5-di(t-butylperoxy)hexane, 2,5
-dimethyl-2,5-di(t-butylperoxy)hexyne, 1-%', ? -1. /:;, Do-0-chlorobenzoyl peroxide 1.1-bis(1-butylperoxy)3.3.5-) Method of curing with organic peroxides such as cyclohexane- or =6
It may be hardened by a hydrosilation addition reaction in which the 1 (aH=on,) group and the SiH bond are hardened with a platinum compound.

Next, examples of the present invention will be given, in which parts are parts by weight, and viscosity is a value measured at 25°C.

Reference Example 1 The molecular chain terminal was blocked with a hydroxyl group. Viscosity is 9.0OOc
Surdimethylsilicone oil 501 containing 0.15 mol% of S vinyl groups and R in the side chain.

r, r -) 500 g of cyclotrisiloxane having a refluoropropyl group was heated at 120°C for 2 hours under a nitrogen gas stream in a 2 t flask, cooled to 70°C after dehydration, and then added with butyllithium. After adding 10i% hexane solution B a, a, and raising the temperature to 150° C. while removing hexane from the ester adapter, viscosity increased +1. After about 3 hours, 975 g of raw rubber-like material (hereinafter referred to as block polymer ①) was obtained with a yield of 97.5%.

Next, this block polymer IttNMR, IR-GP
When analyzed with O, it was confirmed that this product was represented by the following formula (% formula %).

Reference Example 2 The molecular chain terminal was blocked with a hydroxyl group. Dimethyl silicone oil 148L with a viscosity of 16c8, fluorosilicone oil 312I with a viscosity of 120c8 and toluene 150.9, which has a side chain K r # rr-) fluoropropyl group, and toluene 150.9. Xt
After stirring at 70°C in a flask, add (
Bisdiethylacet) dimethylsilane 34. ! After about 7 hours, a transparent oily substance was obtained, which was washed with water, dried, passed through an IJ tube, and the toluene was removed. An oily substance 423I (hereinafter referred to as block polymer I) having a refractive index of 1.3875 was obtained in a yield of 92%.

Next, this block polymer ■ was subjected to NMR.

Analysis by IR and GPO confirmed that this was expressed by the following formula.

Reference Example 3 Cyclotrisiloxane 400I with r # r # r-F lifluoropropyl group in the side chain! , 100 g of hexamethylcyclotrisilane and 74 p of tetrachlorosilane were thoroughly stirred in 7 rass of 1z, and then 69 hexamethylphosone triamide () IMPA) was added, generating 1 heat and producing a transparent oily substance. was obtained, and after stirring at room temperature for 2 hours, 300 d of methyl chloride was added and dissolved, and this was dissolved in 20 d of sodium hydrogen carbonate.
It was dropped into an aqueous solution of 2,500Ii in which 0g was dissolved and hydrolyzed, washed with water, dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure.
．． 3870. Transparent oily substance with specific gravity of 1.2425 5
15JiN or less (referred to as block polymer ■) has a yield of 95
Obtained in %.

Next, this block polymer ■ is subjected to NMR and IR.

When analyzed by GPO, it was found to be represented by the following formula.

Reference Example 4 When 16.110.1 mol of vinyltrichlorosilane) and 744.4 fl (0.2 mol) of hexamethylcyclotrisiloxane were stirred in the presence of HMP 0.6II for 2 hours, the result was shown by formula 1. Chlorooil ■ was obtained.

In addition, vinyltrichlorosilane 16.1, li' (
Cyclotrisiloxane 46.8Ii (0.1 mol) with r, r, r-)rifluoroglobyl groups
When the mixture was stirred for 2 hours in the presence of &HMPA o, 6.9, chlorooil (2) represented by formula 1 was obtained.

Next, 60.5 g of this Chlorooil ■, 62.9II of Chlorooil ■, and 100 g of trichlorethylene were mixed, and this was dropped into 300 d of water for hydrolysis.
After stirring for an hour, the liquid was separated, washed with water, dried, and the solvent was removed with a strip, resulting in a viscosity of 48.7°. Refractive index 1.4
A clear oil of 012 was obtained.

Next, add bis(diethylamino) to this oily substance 80I.
Dimethylsilane 4! After adding i and stirring at 25° C. for 4 hours, excess 7-minosilane was removed by stripping under reduced pressure of 4 mtHg, and an oily substance with a viscosity of 70 cS (hereinafter referred to as block polymer ①) was obtained.

Next, this block polymer ■ is subjected to NMR and IR.

When analyzed using ()PO, it was confirmed that this was represented by the following formula.

Reference Example 5 Raw rubber-like block poly 1-110 obtained in Reference Example 1
0 part has a specific surface area of 200n? /11 smoke-quality silica 28 parts 1 molecular chain end blocked with hydroxyl group, viscosity 150c8 r
, r, r-) 5 parts of refluoropropylmethylsiloxane oil were kneaded.

A silicone rubber paste was prepared by heat treatment at 150° C. for 1 hour.

2.5-dimethyl-2 to 100 parts of this rubber paste
, 5-di(t-butylperoxy)hexane, 5 parts were added and thoroughly kneaded with a mixing wheel, and then 30
Press release for 10 minutes at 165°C under pressure of Kf/clI 1
to create a rubber elastic body.

I investigated the physical properties of this product at 25°C.

The following results were obtained.

Hardness (JIE3), 46 elongation (%)
200 tensile strength Kf/cd) 7° body! lI change rate (after 70 hours immersion at VC25°C in Fuel D) 110
% Fluorosilicone rubber compound FE-251U (product name behind Shin-Etsu Chemical Co., Ltd.) whose basic unit is the siloxane unit shown in Examples 1 and 2, and dimethyl silicone rubber compound KE-171U (product name manufactured by Shin-Etsu Chemical Co., Ltd.) ) and the block polymer ■ obtained in reference f111 were blended in the proportions shown in Table 1, and a sheet-shaped molded product was made in the same manner as in Reference Example 5. The dumbbell characteristics of this product were as listed in Table 1. ], no delamination phenomenon was observed in these K's.

Examples 3 to 9 When the block polymer in Example 1 (block polymer @ obtained in Reference Example 3.4 instead of IIK) was blended as shown in Table 2, I
] The results were obtained.

Claims (1)

[Claims] 1. A) General formula R^1_aR^1_bSiO_[_4_
−_(_a_+_b_)_]_/_2(R^1 here,
R^2 is the same or different unsubstituted or substituted monovalent hydrocarbon group, a, b are positive numbers where a≧0, b>0, 1.95<a+b<2.05) Siloxane and b) General formula R^3_cR^4_dSiO_[_4_-_
(＿c＿＋＿d＿)＿]＿／＿２〔Here is R^3, R^
4 is the same or different unsubstituted or substituted monovalent hydrocarbon group (however, R^4 is different from R^1, R^2, R^3) c,
d is a positive number with c≧0, d>0.1.95<c+d<2.05] 100 parts by weight, c) General formula R^1_eR^2_fR^3_gR^ 4_hSiO_[
＿４＿−＿(＿e＿＋＿f＿＋＿g＿＋＿h＿)＿／＿
2 (here R^1, R^2, R^3, R^4 are the same as above, e, f, g, h are e≧0, f>0, g≧0, h>0, 0 A silicone rubber composition characterized by comprising: 0.1 to 100 parts by weight of an organopolysiloxane represented by <e+f+g+h<4); and d) 5 to 200 parts by weight of a finely powdered silica filler. 2. The silicone rubber composition according to claim 1, wherein organopolysiloxanes a) and b) contain 0.025 to 10 mol% of unsaturated groups. 3. The silicone rubber composition according to claim 1, wherein the organopolysiloxane (2) contains at least one unsaturated group in its molecule. 4. The silicone rubber composition according to claim 1, wherein R^4 is a 1,1,1-trifluoropropyl group.