JPH0247158A - Organopolysiloxane composition - Google Patents

Abstract

PURPOSE:To obtain a composition which can give a foam of high methanical strengths when cured and formed by mixing three specified polysiloxanes with a polymer and a platinum metal catalyst. CONSTITUTION:The title composition comprises a vinylorganopolysiloxane of formula I, an organohydrogenpolysiloxane having at least two units of formula II in the molecule, an organohydroxypolysiloxane having at least three units of formula III in the molecule, a polymer containing units of formulas I and II (wherein R<2> is a monovalent hydrocarbon group), and SiO2 and containing 0.01-0.2mol/100g Si-bonded hydroxyls and a platinum metal catalyst. In the formulas, R<1> is an alkyl, a cycloalkyl or an aromatic group; n is 50-2000; a is 0, 1 or 2; b, a+b, c, d, c+d are each 1, 2 or 3; and R<2> is a monovalent hydrocarbon group.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an organopolysiloxane composition, and in particular, an organopolysiloxane composition that can be cured and foamed to obtain a foam having high mechanical strength. relating to things.

[Prior Art] Silicone rubber compositions that foam at room temperature or by slight heating are known, and include, for example, organohydrodiene polysiloxanes having hydrogen atoms bonded to silicon atoms;
A composition in which an organohydroxypolysiloxane having a hydroxyl group bonded to a silicon atom undergoes a dehydrogenation reaction in the presence of a quaternary ammonium salt, a heavy metal carboxylate, an alkali metal alkoxide, etc. as a dehydrogenation reaction catalyst (Japanese Patent Publication No. 33 -9297, Japanese Patent Publication No. 44-8755), compositions reacted using platinum group metal catalysts (Japanese Patent Publication No. 45-8755),
No. 12675, Special Publication No. 52-42826, Special Publication No. 1982
-23462, JP-A-59-196330), etc. are known.

[Problem to be solved by the invention]

However, silicone rubber foams obtained by curing and foaming these compositions all have low mechanical strength and are not suitable for use as heat insulating materials, covering materials, and the like.

Therefore, an object of the present invention is to provide an organopolysiloxane composition that can be cured and foamed to obtain a foam having high mechanical strength.

[Means to solve the problem]

In order to solve the above problems, the present invention provides (A) General formula (I): [In the formula, a plurality of R's may be the same or different, and are substituted or unsubstituted alkyl groups, cycloalkyl groups, or aromatic groups. group, n is an integer of 50 to 2000] Vinyl group-containing organopolysiloxane represented by (B) formula (■): R
' is the same as above, a is Oll or 2, b is 12
or 3, a + b is 1.2 or 3] Organohydrodiene polysiloxane (C) formula (■) having two or more units represented by the following in one molecule: R'c(OH)asioLLL, , (m) (R1 is the same as above, C is 0, 1 or 2, d is 1.2 or 3
, c+d is 1.2 or 3] Organohydroxypolysiloxane having three or more units in one molecule, (D) R'3SiO0,S , R'5 in one molecule
f01.5 [Here, R1 is the same as above, R2 represents a substituted or unsubstituted monovalent hydrocarbon group] and a unit represented by Sing, and a hydroxyl group bonded to a silicon atom is 0. 01-0.2 mol/10
0g of a polymer and (E) a platinum group metal catalyst.

The vinyl group-containing organopolysiloxane which is component (A) of the composition of the present invention is represented by the general formula (1). A plurality of R1s in the formula may be the same or different,
A substituted or unsubstituted alkyl group, cycloalkyl group, or aromatic group, such as an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group; a cycloalkyl group such as a cyclohexyl group; a phenyl group, a tolyl group, etc. aryl group; or a group in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with a halogen atom, a cyano group, etc., such as a chloromethyl group, a trifluoropropyl group,
A cyanoethyl group, etc., and from the viewpoint of raw material availability, price, etc., it is preferably a methyl group or a phenyl group, or a case where some of the plurality of R's are methyl groups and the rest are phenyl groups. . n is an integer from 50 to 2,000, preferably from 200 to 1,000.

In addition, the vinyl group-containing organopolysiloxane that is component (A) usually has a viscosity of 20 to 10 at 25°C.
,000,0OOcP, preferably 5,000-10
It is of 0.000 cP. If the viscosity is too high, the resulting composition will have a high viscosity, and the workability during foaming and curing will decrease.

The organohydrodiene polysiloxane which is component (B) of the composition of the present invention has two or more units represented by the above formula (II) in the molecule.

R1 in formula (II) is a substituted or unsubstituted alkyl group, cycloalkyl group, or aromatic group, as in general formula (I), a is 0, ■, or 2, and b is l , 2 or 3, a+b is 1.2 or 3.

25°C of this organohydrodiene polysiloxane
The viscosity at is usually 1 to 10,000 cP, preferably 50 to 500 cP. If the viscosity is too high, the resulting composition will have a high viscosity and the workability of foaming and curing will decrease.

The organohydroxypolysiloxane which is component (C) of the composition of the present invention is linear, branched or cyclic having three or more units represented by the above formula (III) in the molecule. R1 in formula (I[I) is a substituted or unsubstituted monovalent hydrocarbon group that is not an aliphatic unsaturated group, and C is 0.1 or 2, as in the above general formula (1). , d is 1.
2 or 3, c+d is 1.2 or 3.

The viscosity of this organohydroxypolysiloxane at 25°C is usually 10 to 10,000 cP, preferably 50 to 500 cP. If the viscosity is too high, the resulting composition will have a high viscosity and workability will decrease.

The organohydroxypolysiloxane which is the component (C) of the composition of the present invention can be produced by, for example, mixing the organohydrodiene polysiloxane (the component (B)) and water with an organic solvent such as acetone, 1,4-dioxane, tetrahydrofuran, etc. This can be easily carried out by carrying out a dehydrogenation reaction in a solvent in the presence of a platinum compound.

Specific examples of the organohydroxypolysiloxane that is component (C) of the composition of the present invention include those represented by the following formula.

The polymer which is component (D) of the composition of the present invention contains units represented by the formulas: R'3Si06.5, R"SiO,,5 and 5i02 in one molecule, and is bonded to a silicon atom. 0.01 to 0.2 mol/loo
g, preferably 0.02 to 0.05 mol/100 g.

R2 in the formula is a substituted or unsubstituted monovalent hydrocarbon group, and for example, in addition to the groups exemplified for R' in the general formula (1), alkenyl groups such as vinyl group and allyl group; vinyloxy group and aliphatic unsaturated groups such as alkenyloxy groups such as isopropenoxy groups. Also this (D
) component has the above formula: RZSiOo, S , R25iO
In addition to the units represented by 1,5 and SiO□, the formula, R1□
It may also contain a unit represented by SiO. This R'
is the same as R1 in the general formula (1).

In the polymer that is component (D) of the present invention, if the amount of hydroxyl groups bonded to silicon atoms is less than 0.01 mol/100g, the crosslinking of the polymer will be insufficient and a foam with sufficient strength will not be obtained. If the amount exceeds 0.2 mol/100 g, the foam regulating properties of the cured foam will decrease.

In this polymer as component (D), R', 5iO
0,.

/Sing molar ratio is preferably 0.01 to 2.0,
More preferably, it is 0.05 to 1.0, and R”5
i01. The molar ratio of s/Sing is preferably 0.01-
1.0, more preferably 0.05 to 1.0.

When the molar ratio of R' 3sioo, 5/5iOz is within the above range, the viscosity of the resulting composition will be favorable for curing and foaming operations, and the strength of the cured product will also be higher. Further, when the molar ratio of R''S!01.S/Si0g is within the above range, the viscosity of the resulting composition will be favorable for curing and foaming operations, and the strength of the cured product will be higher.

Furthermore, the polymer that is component (D) of the composition of the present invention is
When containing a unit represented by the formula, R1□SiO, R1
□SiO/5i (molar ratio of h is preferably 0.01 to 1
．． 0, more preferably 0.05 to 0.5. In this case, when the molar ratio of R1□S iO/S iOz is within the above range, the viscosity of the resulting composition will be favorable for curing and foaming operations, and the strength of the cured product will be higher.

Specific examples of the polymer that is component (D) include those represented by the following average composition formula.

((CH+)+5iOa, s) ((Ctl+') 5siOo, s),. (CH2
SiO,,3], (SiO□) aa (00,5H
)24 (CHz・C1l-5iO+, s ]2 (
CIIsSiO+, s) b[SiO□]4゜[0
゜, J]z ((CI+3) zsio.,,],.[]C11□-
Ctl-3iO,,5, (C113SiOI,5) 4
(Sing) 4゜[0゜,, II).

((CH3)isiOo,s) za (Cdl,5i
Ot, s ) 3 (Si(lz) xy[0°, 5
ll): + In the composition of the present invention, the blending ratio of component (B) is usually 1 to 1 of component (B) to 100 parts by weight of component (A).
The amount of component (B) is 5 to 60 parts by weight per 200 parts by weight, preferably 100 parts by weight of component (A). If the amount of component (B) is too large, the resulting composition will have a high viscosity and the workability of foaming and curing will be reduced, and if it is too small, a foam with sufficient strength will not be obtained. The blending amount of component (B) is (silicon bonded to the hydrogen atom in component (B))/(silicon bonded to the aliphatic unsaturated group and hydroxyl group in component (D), and (B). ) The molar ratio of the total amount of silicon bonded to hydroxyl groups in component (B) is adjusted to be 0.6 to 40.The amount of component (B) is small;
If the molar ratio is less than 0.6, the amount of gas generated by the dehydrogenation reaction of component (B), component (C), and component (D) will decrease, and the expansion ratio of the resulting foam will decrease. B)
If the amount of the components blended is too large and the molar ratio exceeds 40, the hardness of the resulting foam will decrease and physical properties such as tensile strength will deteriorate.

In the composition of the present invention, the blending ratio of component (C) is usually 1 to 1 to 100 parts by weight of component (8).
The amount is 200 parts by weight, preferably 5 to 40 parts by weight of component (C). If the amount of component (C) is too large, a foam with sufficient hardness and strength will not be obtained; if it is too small, (B)
The amount of I+2 gas generated by reacting with the components decreases, and the foaming ratio decreases. . In addition, the blending amount of this (C) component is (silicon bonded to the hydroxyl group in the (C) component)
The molar ratio of /(total of aliphatic unsaturated groups in component (D) and vinyl groups in component (A)) is adjusted to be 0.1 to 10. If the blending amount of component (B) is small and the above molar ratio is less than 0.1, the amount of gas generated by the dehydrogenation reaction with component (B) will be small, and the expansion ratio of the resulting foam will be reduced. , the blending amount of component (C) is too large and the above molar ratio is 1.
If it exceeds 0, the resulting foam will have a lower hardness and a lower tensile strength.

In the composition of the present invention, the blending ratio of component (D) is (
1 to 200 parts of component (D) per 100 parts by weight of component A)
parts by weight, preferably based on 100 parts by weight of component (A) (
D) component is 20 to 100 parts by weight. If the amount of component (D) is too large, the resulting composition will have a high viscosity, resulting in poor foaming and curing workability, and if it is too small, a foam with sufficient strength will not be obtained.

The platinum group metal catalyst that is component (IE) of the composition of the present invention is not particularly limited, and may be the same as those used for foaming and curing conventional silicone rubber foams.

Examples include chloroplatinic acid, a complex of platinum and an olefin, a complex of platinum and a vinyl group-containing silane or siloxane, a phosphite complex of platinum, a phosphine complex of platinum, and the like.

In the composition of the present invention, the blending amount of the platinum group metal catalyst as the component (IE) is as follows (A), (B), and (C).
Usually 1 to 200 p based on the total amount of component (D)
pm, preferably 5 to 50 ppm.

The composition of the present invention includes the above (A), (B), and (C).
, (D) and (E) by uniformly mixing predetermined amounts of the components.

In addition, the composition of the present invention contains finely powdered silica, calcium carbonate, calcium silicate, titanium dioxide, ferric oxide, etc., in order to further improve the mechanical strength of the foam obtained by foaming this composition. An inorganic filler such as zinc oxide or carbon black may be added in an amount of 1 to 100 parts by weight. Furthermore, in order to promote foaming, an organic foaming agent such as azobisisobutyronitrile, N,N'-dimethyl-N,N'-dinitrosoterephthalamide, etc. may be added, or methanol, It is also optional to add low boiling point compounds such as cyclohexane and freon, surfactants, pigments, dyes, heat resistance improvers, flame retardance improvers, adhesiveness improvers, and the like.

Curing and foaming of the composition of the present invention can be carried out by leaving it at room temperature, but it can be carried out in a shorter time by heating it to 30 to 70°C.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples and Comparative Examples.

Synthesis Example 1 (Synthesis of component (C)) Methylhydrodiene polysiloxane 600 represented by the formula:
Dissolve g in 2000 g of acetone and add 1% of chloroplatinic acid.
Add 9.7g of isopropyl alcohol solution to 50-6
After heating to 0°C, drop 50g of water to 50-60"
The reaction was carried out at C for 3 hours. Next, 3 hours of activated carbon and 250 g of anhydrous sodium sulfate were added and stirred for 2 hours, and then the reaction mixture was filtered and acetone was removed at 40°C and 30 Torr to obtain methylhydroxypolysiloxane represented by the following formula.

When the viscosity, specific gravity and refractive index of the obtained methylhydroxypolysiloxane were measured, they were 63 cP and 1, respectively.
．． 018 and 1.410. Also, from the above formula,
The content of silicon-bonded hydroxyl groups in this methylhydroxypolysiloxane is 0.40 mol/100
It is calculated as g.

Synthesis Example 2 (Synthesis of component (D)) To a mixture consisting of 378.0 g of tetraethoxysilane, 1 g of methyltrimethoxysilane, 153.0 g of hexamethyldisiloxane, 100 g of toluene, and 10 g of isopropyl alcohol, 5.0 g of a 35% aqueous solution of hydrochloric acid was added. 0 g and further 133.2 g of pure water were added dropwise, and the mixture was reacted at 77° C. for 5 hours. Next, after cooling, 5.5 g of sodium hydrogen carbonate and 500 g of toluene were added, and the mixture was heated to 111° C. to distill off isopropyl alcohol and water. After that, it was further heated to 113°C for 3
After heating for an hour, it was cooled. Next, after adding 7 g of a 35% aqueous solution of hydrochloric acid and curing at 85 to 90°C for 6 hours, it was cooled, 6.0 g of sodium hydrogen carbonate and 30 g of anhydrous sodium sulfate were added, and after being left for 1 hour, it was filtered. A polymer represented by the following average composition formula: % formula %) (hereinafter, this polymer will be referred to as [polymer A-
1) was obtained.

The viscosity, specific gravity, pi, and nonvolatile content of the obtained polymer A-1 were measured, and they were 6.1 cP, 1, and 0, respectively.
27, 4.59 and 52%. Further, from the above formula, the content of hydroxyl groups bonded to silicon atoms in polymer A-1 is calculated to be 0.04 mol/100 g.

Furthermore, in the same manner as above, the following average composition formula: % formula %: Content of hydroxyl group bonded to silicon atom 70.0
4 mol/long Polymer A-3: ((Cll3)+5iOo,s) x4(C1l□・C
ll-5iO+, s) z(Cll3SiO+, s)
b (SiOz) 40 (Oo, 5ll) z Content of hydroxyl groups bonded to silicon atoms: 0.03
Mol/100g Polymer A-4: ((C113)3sioo,s) 24 (Cnflq
SiO+,s) :1(SiO□) :+i(o.,
5H)z Polymers A-2 to A-4 having a content of hydroxyl groups bonded to silicon atoms of 70.04 mol/100 g were produced.

Examples 1 to 4 Average compositional formula: α,ω-divinyldimethylpolysiloxane (
Viscosity: 10,000 cP), methylhydroxypolysiloxane obtained in Synthesis Example 1 above, formula: methylhydrodiene polysiloxane, and polymers A-1 to A-4 obtained in Synthesis Example 2 above, in a formulation shown in Table 1. This was mixed with an isopropyl alcohol solution of chloroplatinic acid (platinum amount: 2% by weight) and fine powdered silica (manufactured by Tatsumori, Crystallite V).
X-X) was added in the amount shown in Table 1 and mixed uniformly to obtain an organopolysiloxane composition.

The obtained organopolysiloxane composition was heated at 20°C for 5
When kept in an atmosphere of 5% (relative humidity) for 1 hour,
It cured and foamed to become a silicone rubber foam. The expansion ratio, hardness (Asuka C), elongation rate, and tensile strength of this foam were measured according to the following methods. The results are shown in Table 1.

Foaming ratio: 20 x 20 x 20am+ from two foams
A sample with the dimensions was prepared and measured using the underwater displacement method.

Elongation and tensile strength: 2 from a sheet of thickness 3III11
A No. 1 dumbbell was punched out and used for measurement.

Comparative Examples 1 to 2 Instead of Polymers A-1 to 4, Polymer-B (Comparative Example 1) represented by the average composition formula: % formula %) or the average composition formula:
((C11,), SiO,,□)□. (SiO□〕4
Polymer-C represented by ゜[0,7□11]3 (Comparative Example 2
) A composition was obtained in the same manner as in Example 1, except that the following was used. The obtained composition was cured and foamed in the same manner as in Example 1 to obtain a silicone rubber foam, and the foaming ratio and hardness (
Asuka C), elongation and tensile strength were measured.

The results are shown in Table 1.

〔Effect of the invention〕

The organopolysiloxane composition of the present invention has high mechanical strength as a foam obtained by curing and foaming.
It is suitable for use as a heat insulator, covering material, etc.

Claims (2)

[Claims] (1) (A) General formula (I): ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [In the formula, multiple R^1 may be the same or different, substituted or unsubstituted alkyl group, represents a cycloalkyl group or an aromatic group, and n is an integer of 50 to 2000.] A vinyl group-containing organopolysiloxane represented by (B) formula (II):
)_}_/_2(II) [R^1 is the same as above, a is 0, 1 or 2, b is 1, 2 or 3, a+b is 1, 2 or 3] Represented by Organohydrodiene polysiloxane having two or more units in one molecule, (C) formula (III): R^1_c(OH)_dSiO_{_4_-_(_c_
+_d)_}_/_2(III) [R^1 is the same as above, c is 0, 1 or 2, d is 1, 2 or 3, c+d is 1, 2 or 3] organohydroxypolysiloxane having three or more units in one molecule; (D) an organohydroxypolysiloxane having three or more units in one molecule; _5, R
^2SiO_1_. _5 [Here, R^1 is the same as above, R^2 represents a substituted or unsubstituted monovalent hydrocarbon group] and contains a unit represented by SiO_2 and a hydroxyl group bonded to a silicon atom. 0.01-0.2 mol/1
An organopolysiloxane composition comprising a polymer containing 0.00 g and (E) a platinum group metal catalyst. (2) The organopolysiloxane composition according to claim 1, wherein R^1_3Si of the component (D)
O_0_. The molar ratio of units represented by _5/units represented by SiO_2 is 0.01 to 2.0, and R^2SiO_
1_. A composition in which the molar ratio of units represented by _5/units represented by SiO_2 is 0.01 to 1.0.