JPH04161459A - Organopolysiloxane composition - Google Patents

Abstract

PURPOSE:To obtain a polysiloxane composition, excellent in preservation stability at ambient temperature and capable of performing homogeneous curing in a short time by mild heating by blending an organopolysiloxane with an organosilicon compound having a specific structure as a preservation stabilizer. CONSTITUTION:An organopolysiloxane composition is obtained by blending (A) an alkenyl group-containing organopolysiloxane expressed by formula I [R<1> is alkenyl; R<2> is monofunctional (substituted) hydrocarbon without containing any aliphatic unsaturated group; a is 1-3; b is 0-2; (a+b) is 1-3] with (B) an organohydrogenpolysiloxane expressed by formula II [R<3> is (substituted) monofunctional hydrocarbon; c is 0-2; d is 1-3; (c+d) is 1-3], (C) a platinum group metallic catalyst and (D) a silane compound expressed by formula III [R<4> and R<5> are (substituted) monofunctional hydrocarbon; R<6> is (substituted) monofunctional hydrocarbon having -CidenticalC- bond; p is 2 or 3; q is 0-3; n is 2-10].

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an addition-curable organopolysiloxane composition having excellent storage stability, particularly at room temperature, and a cured product thereof.

(Prior art) Addition-curing organopolysiloxane compositions are generally
The main components are an alkenyl group-containing organopolysiloxane, an organohydrodiene polysiloxane, and a platinum-based catalyst. This composition is required to be able to be stored stably at room temperature for a long time in a mixed form of all its components, and to be able to cure only when heated.

For this purpose, the composition usually contains a storage stabilizer to improve storage stability at room temperature.

(Problems to be Solved by the Invention) Examples of the storage stabilizers include benzotriazole (Japanese Patent Publication No. 40-25069), acetylene group-containing alcohol (Japanese Patent Publication No. 44-31476), and acrylonitrile (Japanese Patent Publication No. 45-22018). Publications) etc. are known. However, these storage stabilizers do not have sufficient desired stabilizing effect, and when the composition is stored at room temperature for a long period of time, problems such as thickening and gelation occur. Furthermore, if a large amount of the above-mentioned storage stabilizer is blended in order to sufficiently suppress this thickening, etc., there arises the disadvantage that more heating or time than necessary is required during heat curing. Furthermore, since these storage stabilizers lack compatibility with polysiloxane, there is also the problem that phase separation occurs during storage at room temperature when a large amount of these is blended.

Especially when a large amount of acetylene group-containing alcohol or acrylonitrile is blended, if hot air curing is performed in an atmosphere at a high temperature of about 150°C, curing will occur only from the surface, resulting in fine wrinkles or unevenness on the surface of the cured product. occurs,
There is a problem that the commercial value of the cured product is significantly impaired.

Furthermore, it has been proposed to use an organopolysiloxane containing an alkenyloxy group as a storage stabilizer (Japanese Patent Publication No. 3774/1983). In this case, the problem of phase separation and the occurrence of wrinkles or unevenness on the surface during hot air curing in a high temperature atmosphere are solved, but the curing takes a long time under mild heating conditions of about 100°C. There is also the problem that the effect of suppressing thickening at room temperature is poor.

Furthermore, the following formula, CI3 (CH3) zSi (0-C-CmiCH)2°CH.

CI(.

glance Cf1zSi(0-C-CECH) 3.

■ A silane compound represented by CH3 has been proposed as a storage stabilizer (Japanese Patent Publication No. 53-35983, Japanese Unexamined Patent Publication No. 59-1
33252). When these storage stabilizers are used, problems of saccharification and phase separation at room temperature can be avoided. However, these silane compounds have a relatively high vapor pressure, and for this reason, most of them volatilize during the vacuum degassing operation performed after kneading with other components.
Curing properties are not constant, and when hot air curing is performed in a high temperature atmosphere, there are unavoidable problems such as wrinkles and unevenness on the surface of the cured product.

Therefore, an object of the present invention is to improve the above-mentioned drawbacks of the prior art, to provide excellent long-term storage stability at room temperature, to cure uniformly in a short time by heating under relatively mild conditions, and to cure. An addition-curing organopolysiloxane composition and its cured product that can be cured uniformly without wrinkles or unevenness on the surface even when hot air curing is performed at high temperatures to shorten the time. It is to provide.

(Means for Achieving the Object) The present invention achieves the above object by using an organosilicon compound having a specific structure having Si-+Ct (, +, Si bonds in the -molecule) as a storage stabilizer. It was a success.

That is, according to the present invention, (A) the following general formula (1), (R')-(R2)bsiO□ [In formula 11, R1 is an alkenyl group, and R2 is an aliphatic unsaturated group. is a monovalent unsubstituted or substituted hydrocarbon group that does not contain, a is an integer of 1 to 3, and b is an integer of 0 to 2 (however, a+b is an integer of 1 to 3) An alkenyl group-containing organopolysiloxane having a structural unit represented by (B) the following general formula (II), R3(HdSiO□ [II] where R3 is a substituted or unsubstituted monovalent hydrocarbon group) , C is an integer of 0 to 2, and d is an integer of 1 to 3 (however, c+d is an integer of 1 to 3). (C) Platinum group metal catalyst; (D) the following general formula (I [I]; where R4 and R5 are each a substituted or unsubstituted monovalent hydrocarbon group; Rh is -C=C - a substituted or unsubstituted monovalent hydrocarbon group having a bond, P is a number of 2 or 3, q is an integer of 0 to 3, and n is an integer of 2 to 10. An organopolysiloxane composition containing a silane compound represented by the following and a cured product thereof are provided.

A Organopolysiloxane containing an alkenyl group as the component (A) used as a base polymer in the present invention has the formula [I], that is, (R') m (R2) bS io, (I
] (wherein R', R", a, b are as described above) as a constituent unit,
It consists of this structural unit and other siloxane units.

In this general formula [■], examples of the alkenyl group R1 include vinyl group, allyl group, l-butenyl group, 1-hexenyl group, etc. Vinyl group is the most advantageous from the viewpoint of ease of synthesis. . Further, as the monovalent hydrocarbon group R2 having no aliphatic unsaturated group, for example, the number of carbon atoms is 1 to
12 groups, preferably groups having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, isopropyl.

Butyl group, pentyl group, hexyl group, octyl group.

Alkyl groups such as decyl group and dodecyl group; cyclopentyl group, cyclohexyl group, cyclobutyl! [cycloalkyl group; aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl group such as benzyl group, phenylethyl group, phenylpropyl group; and a part of the hydrogen atom of these hydrocarbon groups or Groups entirely substituted with halogen atoms such as chlorine, fluorine, and bromine, cyano groups, etc. 2 For example, halogenated carbonization of chloromethyl group, trifluoropropyl group, chlorophenyl group, dibromophenyl group, tetrachlorophenyl group, difluorophenyl group, etc. hydrogen group or β
Examples include cyanoalkyl groups such as cyanoethyl group, T-cyanopropyl group, and β-cyanopropyl group. Most preferably, the group R2 is a methyl group because of its good properties.

In the present invention, the structural unit represented by the above-mentioned general formula [I] preferably contains two or more alkenyl groups in one molecule. In addition, the structural unit may be present at either the molecular end or the molecular chain of the organopolysiloxane, or both, but in order to provide excellent mechanical strength to the composition after curing, at least the molecular end Preferably, it exists in

Moreover, as a structural unit other than the above-mentioned structural unit, there can be mentioned a siloxane unit represented by the following formula in which a hydrocarbon group similar to R2 above is bonded to a silicon atom.

R2) SiO+zz, RlzSiOzzt
R”5i0372 The above-mentioned organopolysiloxane may be linear, branched, or cyclic, or may be a mixture thereof.The viscosity of this organopolysiloxane at 25°C is 25 to 500,000. cS
It is preferable that the value be within the range of t.

Specific examples of the organopolysiloxane preferably used in the present invention include, but are not limited to,
It is as follows.

(However, in the above formula, i is 1, 2 or 3, e+g.

j and 2 represent positive integers, and f, h, k and m represent 0 or positive integers. ) B Organohydrodiene polysiloxane The organohydrodiene polysiloxane as component (B) used in the present invention is represented by the general formula % (wherein R', c, and d are as described above). It has a structural unit and acts as a crosslinking agent. That is, the cured product is formed by the addition reaction of the SiH group contained in the above structural unit with the alkenyl group in the organopolysiloxane (A).

In the above general formula (It), the substituted or unsubstituted monovalent hydrocarbon group R3 is exemplified by the same groups as the group R2 in the above general formula (I), but from the viewpoint of ease of synthesis, the methyl group is the most preferred.The structural unit may be present either at the end of the molecule or in the middle of the molecular chain.

Moreover, as structural units other than the above-mentioned structural units, the structural units shown by the following formula can be mentioned, which are similar to the structural units other than general formula (1) in component (A).

R"3SiO,, □, R1□5iOzz□, R"5
The organohydrodiene polysiloxane having such structural units as i037□, SiO□ may be linear, branched, or cyclic, or may be a mixture thereof, and its viscosity at 25°C is 0. 5-10,00
0 cst(7) range.

Specific examples of such organohydrodiene polysiloxanes include, but are not limited to, the following.

(a) Branched organohydrodiene polysiloxane consisting of (CH:+)JSiO+zz units and Sing units.

0)) A linear organohydrodiene polysiloxane represented by the following formula: l CH3HCHi CH3 (wherein p is 3 to 300. q is an integer theal of 0-100771).

(C) A linear organohydrodiene polysiloxane represented by the following formula: (wherein P is an integer from 1 to 100. q is an integer from 0 to 1oo).

It is desirable to use the above-mentioned organohydrodiene polysiloxane that has good compatibility with the organopolysiloxane of component (A), depending on the type of organopolysiloxane.

Such an organohydrodiene polysiloxane has: SiH4 of 0.25 to 4.0 mol per mol of alkenyl group of the organopolysiloxane of component (A);
In particular, it is preferable to use it in an amount of 0.3 to 3.0 mol. By using such an amount of organohydrodiene polysiloxane, curing of the composition proceeds sufficiently, and a cured product having favorable properties such as hardness and strength can be obtained.

C7 The platinum metal catalyst of component (C) used in the present invention promotes the addition reaction between the alkenyl group of component (A) and the hydrosilyl group (3SiH group) of component (B). , for example, simple platinum (platinum black), chloroplatinic acid,
There are platinum-olefin complexes, platinum-alcohol complexes, platinum coordination compounds, platinum held on a carrier such as alumina or silica, and palladium-based and rhodium-based ones, but platinum-based ones are preferred. It is. In particular, chloroplatinic acid or a platinum-olefin complex is preferably used after being dissolved in an alcohol solvent, a ketone solvent, an ether solvent, a hydrocarbon solvent, or the like. In addition, solid materials need to be finely pulverized to improve dispersibility, and it is preferable that the carrier used has a small powder diameter and a large specific surface area.

Such a catalyst usually has a platinum equivalent of 0 with respect to component (A).
．． It is blended in a proportion of 1 to 500 ppm. When the amount is less than this range, the desired addition reaction promoting effect cannot be obtained, and even if a large amount is used, no improvement in the curing rate can be obtained at a given yield, which is only economically disadvantageous.

D Scene Person In the present invention, the silane compound used as component (D) has the general formula [■], that is, (in the formula, R4 to R6+
p+ Q+ n is represented by (as described above). - As is clear from the general formula (II[), this silane compound is a molecule having a Si+CHz+-fiSi bond and at the same time a hydrocarbon group having a -C=C- bond bonded to a silicon atom via an oxygen atom. It has a structure. In relation to such a molecular structure, this silane compound acts as a storage stabilizer, imparting long-term storage stability to the composition at room temperature, and at the same time, extremely high temperature dependence during heat curing. Furthermore, it provides uniform curing properties even in hot air curing at high temperatures. In particular, the Sr + CHz ) 115I bond contained in the molecule gives the composition significant temperature dependence during heat curing.

In the above general formula CI [[), P is a number of 2 or 3, and q is an integer of 0 to 3, but from the viewpoint of storage stability of the composition at room temperature, p = q = 3. It is preferable that there be.

Further, n is an integer of 2 to 10, but from the viewpoint of ease of synthesis of the siloxane compound and availability of raw materials for synthesis, it is most preferable that n=2.

R4 and R5 each represent a substituted or unsubstituted monovalent hydrocarbon group, and those having 1 to 1 o carbon atoms are particularly preferred, such as alkyl groups such as methyl, ethyl, and propyl groups, phenyl groups, Aryl group such as tolyl group, 2-
Examples include aralkyl groups such as phenylethyl group and 2-phenylpropyl group, and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as chlorine atoms or fluorine atoms.

Further, R6 is a substituted or unsubstituted monovalent hydrocarbon group having a -C=C- bond, for example, the following general formula: Examples include a group represented by the following, which represents a lower alkyl group having 6 or less carbon atoms, such as a group, or a phenyl group, which may be bonded to each other to form a ring.A particularly preferable group R6 is , as follows.

CHx C) 12CH3Ph In the present invention, specific examples of the silane compound used as the above i+E (D) component are as shown below, although they are not limited thereto.

CH2’cn.

CH3CH3GHz (HC:CC0):+5iCHzCHzSi(OCCmiCH)z.

CH3CH3 CHy CHz CHz I I+ (HC=-CCO) :+5iC)lzcHzsi(O
CC=CH).

l　　　　　　lI C1, CH3CH.

CH□ CHff (HC::CC0)+5iCHzCHzSi CH:
l.

CH3ctt3 CH, CH3CHff CL l 1 1 1 (HCECCO)zsicHzcHzsi(OCCEC
H)z.

lI CI (3CH.

CH3CHs CH3CH3 1I 1 1 (HCCIC0)zsicHzcHzsi (OCCI:
CH).

l 11 CFI:l CH:l CH3CI(3C
H3 CH3Ph Ph CH3 II 11 (HCECCO)zsicHzcl(zsi(OCCE
CH)z.

CHj　　　　　　　CH.

CB, CH2Cl:l
CH3 (HCECCO) 5sicHzcHzsi (OCC
= CI)s.

ph ph These silane compounds are generally used in an amount of 2 to 10 gram equivalents of the platinum group metal of the platinum group metal catalyst of component (C).
It is preferred to use an amount sufficient to provide ,000 gram equivalents of -C=C- bonds.

In addition to the above-mentioned components, various compounding agents known per se can be added to the composition of the present invention.

For example, by blending an inorganic filler as necessary, it is possible to provide flowability, hardness after curing, tensile strength, elongation, modulus, etc. suitable for the intended use. Such inorganic fillers include fumed silica, silica aerogel, precipitated silica, ground silica, diatomaceous earth, iron oxide,
Examples include zinc oxide, titanium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, and carbon black. The blending amount of these inorganic fillers is arbitrary as long as it does not impair the purpose of the present invention.

It is also possible to add appropriate pigments, dyes, antioxidants, etc., if necessary.

Organopolysiloxane The organopolysiloxane composition of the present invention is easily prepared by uniformly mixing the above-mentioned components, can be stored stably at room temperature for a long period of time, and when heat-cured, the curing temperature dependence is low. Because it is significantly larger than conventional compositions, it cures quickly with gentle heating, and even when hot air cured at high temperatures, it cures uniformly from the surface to the inside without creating wrinkles or unevenness on the surface. It has the characteristic of being able to

This composition is useful as a so-called wave type composition, but it can also be used as a so-called condensate type composition in which each component is divided into two or more liquids and mixed at the time of use.

The composition of the present invention is useful for silicone rubbers such as potting materials and coating materials in the electrical and electronic industries, briping materials in the general industry, rubber materials for mold molds, molding materials, coating materials for release paper, and dental impression materials. , silicone gel, silicone resin, etc.

(Example) In the following examples, all "parts" mean "parts by weight",
In addition, the preparation of mixtures, defoaming operations, and viscosity measurements are carried out at 25°
I went with C.

100 parts of dimethylpolysiloxane (viscosity 1, 0OOcP) whose molecular terminals are capped with vinyldimethylsilyl groups.The following formula: CHz CH3CH3 CHzSiO+5iO) + s+5iO) + 5s
Mix 8 parts of methylhydrodiene polysiloxane represented by icH3CH, CH, H and further mix 0.01 part of any one of the following silane compounds (a) to (d) to prepare a mixture of four types. did.

CFl, CH.

(a) (HCECCO) :+5iCIhCHzS
i (OCCE:CH) 3CH3C1(ff CH:l CHs CH:+ l II (c) (HCECCO) 3SiCHzCHzSi
(OCC”:CH) zCH3CH:I C1,CH,CH3CHff l l 1 1 (c) (IC:CC0)zsicHzcHzsi(
OCC:CH)zCH3CHi CHz CH3CHx C1h II II (d) (HCECCO)zsicHzcHzsi(
OCC=CH)CHz CH3CH3 Next, a 2-ethylhexyl alcohol solution of chloroplatinic acid was added to each mixture so that the amount of platinum was 5 ppm based on the total amount, and the mixture was uniformly mixed to form compositions (a) to (d) was prepared.

Furthermore, the above compositions (a) to (d) were left to stand under conditions of a certain degree of vacuum for a certain period of time to perform defoaming. After defoaming, 25°
Table 1 shows the viscosity of each composition after 30 minutes and 6 hours after the completion of mixing. Further, Table 2 shows the time required for curing the above composition when heated to 150°C and the appearance after curing.

Comparison ■Soil In Example 1, the composition (e ) to ((2) were prepared.

lh (e)　CHzSi+OCC:CH)z“ CI3 CH3 Ge) (CH3)zsi+OccmiC))2CI.

CH3 (g) (CH:l) zsi + 0CC=CH)
CH.

For the compositions (e) to (turbidity), the viscosity after defoaming under reduced pressure, the time required for heat curing, and the appearance after curing were measured in the same manner as in Example 1, and the results are shown in Tables 1 and 2. Shown in the table.

This flλ In Example 1, a composition (5) was prepared without blending each of the silane compounds (a) to (d) at all. This composition cures at 25°C 5 minutes after mixing the components,
It became rubbery.

(Effects of the Invention) According to the present invention, the storage stability of an addition-curing organopolysiloxane composition at room temperature is significantly improved, and it can be cured uniformly in a short time by heating under relatively mild conditions. Furthermore, even when curing is performed using high-temperature hot air to shorten the curing time, uniform curing can be achieved without wrinkles or unevenness on the surface.

By using the organopolysiloxane composition of the present invention having the above characteristics, it is possible to shorten various manufacturing steps, extend the working time of the composition, and save energy by curing by heating at low temperatures.

Claims (2)

[Claims] (1) (A) The following general formula [I], (R^1)_a(R^2)_bSiO_{_4_-_(
_a_+_b_)_}_/_{_1_} [I] In the formula, R^1 is an alkenyl group, and R^2 is a monovalent unsubstituted or substituted hydrocarbon group containing no aliphatic unsaturated group. , a is an integer of 1 to 3, and b is an integer of 0 to 2 (however, a+b is an integer of 1 to 3). Siloxane, (B) General formula [II] below, R^3_cH_dSiO_{_4_-_(_c_+_d
_)_}_/_{_2_}[II] In the formula, R^3 is a substituted or unsubstituted monovalent hydrocarbon group, c is an integer from 0 to 2, and d is 1 An organohydrodiene polysiloxane having a structural unit represented by (C) a platinum group metal catalyst, (D) the following general formula [III ], ▲There are mathematical formulas, chemical formulas, tables, etc.▼[III] In the formula, R^4 and R^5 are each a substituted or unsubstituted monovalent hydrocarbon group, and R^6 is -C≡C - a substituted or unsubstituted monovalent hydrocarbon group having a bond, p is a number of 2 or 3, q is an integer of 0 to 3, and n is an integer of 2 to 10. An organopolysiloxane composition containing a silane compound represented by: (2) A cured product obtained by curing the composition according to claim (1).