JP2003128924A - Room temperature curable polyorganosiloxane composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a room temperature curable polyorganosiloxane composition quickly curing, and having a large elongation rate and a strong tensile strength at elongation in its cured product. SOLUTION: The room temperature curable polyorganosiloxane composition comprises (A) (A1) a polydiorganosiloxane having >2 ketoximato groups in average in a molecule and having a viscosity of >=20,000 cP, and/or (A2) polydiorganosiloxane having >=2 silanol groups and/or ketoximato groups in a molecule, and a ketoximato-containing silane as a crosslinking agent. The composition contains (B) 0.01-10 pts.wt. of a curing catalyst and (C) 30-200 pts.wt. of calcium carbonate having an average particle size of 0.03-0.15 μm and a bulk density of >=280 ml/100 g, whose surfaces having been treated with a saturated or unsaturated linear fatty acid, or its alkali metal salt based on 100 pts.wt. of the component (A).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a room temperature curable polyorganosiloxane composition, and more particularly to a room temperature curable polyorganosiloxane composition, which is stable under sealed conditions in the absence of moisture and cured at room temperature upon contact with moisture in the air. To produce a rubber-like elastic body exhibiting high strength and high extensibility, which is useful as a structural elastic adhesive for low-to-middle-rise buildings or an elastic adhesive for products requiring rapid extensibility such as airbags. It relates to a curable polyorganosiloxane composition.

[0002]

2. Description of the Related Art Among polyorganosiloxane compositions which cure at room temperature to form a rubber-like elastic material, a so-called room-temperature-curable polyorganosiloxane composition which undergoes a curing reaction upon contact with moisture in the air is known. In general, a silanol group-terminated polydiorganosiloxane having a molecular terminal blocked with a hydroxyl group is mixed with a crosslinking agent having more than two hydrolyzable groups in the molecule and a filler such as silica or calcium carbonate. Since it is composed and has excellent adhesiveness, it is widely used as an elastic adhesive or a coating material in the electric and electronic industries and as a sealing material for construction. Further, recently, in order to protect drivers and passengers, it is being considered to use it for a seal portion of an airbag which is obliged to be installed in a vehicle.

Further, since the airbag needs to be rapidly inflated at the time of operation, not only the adhesive used for the sealing portion thereof is greatly expanded at the time of operation but also the strength required at the time of expansion is maintained. Required.

In general, detached houses generally do not require a highly stretchable adhesive due to their structure, but the number of relatively middle- and high-rise buildings has been increasing due to the recent deregulation, and the elasticity used. There is an increasing demand for adhesives with high stretchability.

[0005]

However, in the conventional room temperature-curable polyorganosiloxane composition, an elongation of about 300 to 500% is generally realized, but an organic amine, amide, or organic hydroxylamine is used as a crosslinking agent. When the elongation is further increased like the composition used in (1), there is a problem that the required tensile strength cannot be obtained.

That is, the room-temperature-curable polyorganosiloxane composition contains a carboxylic acid such as acetic acid, an organic amine, an amide, an organic hydroxylamine, an oxime compound, an alcohol, and acetone at the time of curing, depending on the kind of the crosslinking agent. discharge. In particular, deoxime type, deacetone type and dealcohol type are often used for the purpose of adhesives, coating materials and the like. On the other hand, a one-pack type room temperature curable composition comprising a polyorganosiloxane having an alkoxy group bonded to a terminal silicon atom, an alkoxysilane, and a curing catalyst is recently used as a material having good storage stability and fast curing. Is starting to appear.

Further, the room temperature curable polyorganosiloxane composition is blended with a filler for the purpose of improving thixotropy and mechanical strength of the cured product, and colloidal silica as a filler and calcium carbonate produced by precipitation (hereinafter, referred to as "filler"). It is known as precipitated calcium carbonate). However, with colloidal silica, the ability of the cured product to follow the adherend is poor and the extensibility is poor, and it is difficult to finely adjust the viscosity because a minute amount of high thixotropic property appears, and the thixotropic property decreases over time. In comparison with such colloidal silica, which has problems such as poor weather resistance and high price, a cured product having a low modulus can be obtained, and thus precipitated calcium carbonate has been widely used as a filler in recent years. When the precipitated calcium carbonate is used for a one-component room-temperature-curable polyorganosiloxane composition that is hardened by moisture in the air, the reaction starts with moisture adsorbed on the surface of calcium carbonate. Surface treatment of calcium carbonate with a surfactant such as an alkali metal salt is performed to stabilize it.

However, in the composition using the precipitated calcium carbonate surface-treated with the above-mentioned surfactant, the mechanical strength is insufficient and the followability to the movement of the adherend is insufficient, so that the extensibility Was desired.

The present invention has been made in order to solve such a problem, and is a room-temperature-curable polyorganosiloxane composition having a high curing rate and a cured product having a very large elongation and a large tensile strength during elongation. The purpose is to provide things.

[0010]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made earnest studies to obtain a room-temperature-curable polyorganosiloxane composition capable of following the movement of an adherend, having high extensibility, and having high strength. As a result of repeated experiments, by using a silicone-based polymer with a specific structure and using a specific surface-treated calcium carbonate as a filler, excellent high extensibility and high strength, which have never been seen before, can be obtained. The inventors have found that a cured product can be obtained and completed the invention.

That is, the room-temperature-curable polyorganosiloxane of the present invention has an average of more than 2 ketoximato groups as silicon functional groups in the (A) (A1) molecule.
A silicon-functional polydiorganosiloxane having a viscosity at 3 ° C. of 20,000 cP or more, and / or (A
2) A room temperature curable polyorganosiloxane composition comprising a silicon-functional polydiorganosiloxane having two or more silanol groups and / or ketoximato groups in the molecule and a silane having a ketoximato group as a cross-linking agent. 0.01 to 10 parts by weight of (B) a curing catalyst, based on 100 parts by weight of A) polydiorganosiloxane;
(C) The average particle size is 0.03 to 0.15 μm and JI
The bulk density specified in S5101 is 280 ml / 100g
The above is the calcium carbonate 30 surface-treated with a saturated or unsaturated linear fatty acid or its alkali metal salt.
˜200 parts by weight, respectively.

In the present invention, the (A) silicon-functional polydiorganosiloxane used as the base polymer comprises (A1) and / or (A2) having a silicon functional group as described above, and the (A1) component is By itself, the catalyst action of the component (B) causes a crosslinking reaction to cure. Further, in the case of the combination of the component (A2) and the crosslinking agent, the catalytic action of the component (B) causes a crosslinking reaction between the component (A2) and the crosslinking agent to cure. In each case, the reaction is a hydrolysis reaction followed by a condensation reaction,
The reaction proceeds due to the presence of water in the air.

The component (A) used in the present invention is typically represented by the general formula:

[Chemical 1] (In the formula, R ¹ represents a substituted or unsubstituted monovalent hydrocarbon group, which may be the same or different, and R ² represents —ZS.
iR ³ represents a _{3-p X} p. Here, Z represents an oxygen and / or divalent hydrocarbon group, R ³ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other, and X represents a hydrolyzable group. Represents a ketoximato group, and p represents a number from 1 to 3. Further, n is the viscosity of the component (A) at 23 ° C. of 20,000 to 1,000,000.
It is the number to make it 0 cP. ) Is a substantially linear polyorganosiloxane. And the terminal group R
² is a silicon-functional siloxy unit having at least one silicon functional group X. That is, the component (A) is
It has at least one silicon-functional group X at each end of the molecule.

R ¹ is a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other. R ¹ is a methyl group, an ethyl group, a propyl group, a butyl group,
Alkyl groups such as pentyl group, hexyl group, octyl group, decyl group, dodecyl group; alkenyl groups such as vinyl group, allyl group; aryl groups such as phenyl group, tolyl group, xylyl group; 2-phenylethyl group Aralkyl groups such as 2-phenylpropyl group, and those in which a part of hydrogen atoms of these hydrocarbon groups are substituted with other atoms or groups, that is, chloromethyl group, 3-chloropropyl group, 3 , A halogenated alkyl group such as a 3,3-trifluoropropyl group; and a substituted hydrocarbon group such as a cyanoalkyl group such as a 3-cyanopropyl group. Of these, the composition is easy to synthesize, the component (A) has a low viscosity relative to the molecular weight, provides good extrudability to the composition before curing, and has good physical properties to the composition after curing. Therefore, it is preferable that 85% or more of all the organic groups are methyl groups, and it is more preferable that substantially all the organic groups are methyl groups.

On the other hand, when heat resistance, radiation resistance, cold resistance or transparency is imparted, a necessary amount of phenyl group is added as a part of R ¹ to impart oil resistance and solvent resistance.
When a 3,3,3-trifluoropropyl group or 3-cyanopropyl group is provided as a part of R ¹ or a surface having coating aptitude is provided, a long chain alkyl group or an aralkyl group is provided as a part of R ^1. , And each of them may be used together with a methyl group, etc., and can be arbitrarily selected according to the purpose.

The R ³ groups bonded to the silicon atom in the terminal group R ² may be the same or different from each other and R ¹
And a substituted or unsubstituted monovalent hydrocarbon group which may be the same as or different from, and are similar to R ¹ .
A methyl group or a vinyl group is preferable because it is easy to synthesize and the reactivity of X is excellent. Further, Z may be the same or different from each other, and examples thereof include an oxygen atom; an alkylene group such as a methylene group, an ethylene group and a trimethylene group; and a divalent hydrocarbon group such as a phenylene group.
Oxygen atom and ethylene group are preferable, and oxygen atom is particularly preferable, because of easy synthesis.

X is at least one hydroxyl group present in the terminal group R ² , or a ketoximato group which is a hydrolyzable group. As the component (A1), those in which X is a ketoximato group are used. Examples of the ketoximato group include a methylethylketoxime group, a dimethylketoxime group, and a diethylketoxime group. One or more Xs in R ² may be the same or different from each other. Ease of synthesis, physical properties of composition before curing, stability during storage, curability,
The methylethylketoxime group is preferred because of its economy and wide range of applications.

The number p of the hydroxyl groups or ketoximato groups X in the terminal group R ² is 1 to 3. Among them, the component (A2) used in the room-temperature-curable polyorganosiloxane composition containing a crosslinking agent is easy to synthesize and can be used in combination with various crosslinking agents. Therefore, X is a hydroxyl group (silanol group) or / Or a ketoximato group, and p is preferably 1. Such silicon-functional polydiorganosiloxanes include, for example, cyclic diorganosiloxane oligomers such as octamethylcyclosiloxane which undergo ring-opening polymerization or ring-copolymerization in the presence of water with an acidic or alkaline catalyst. It can be obtained by introducing a hydroxyl group bonded to a silicon atom into the end of the linear polydiorganosiloxane.

The ketoximato group in which X is a hydrolyzable group can be synthesized, for example, by condensing a polyorganosiloxane having a hydroxyl group at a terminal with two or more silanes having an arbitrary ketoximato group. . In this case, since one ketoximato group of the silane is consumed by this condensation reaction, the number p of X in the terminal group R ² of the polyorganosilosan obtained by the reaction is p.
Is one less than the number of X in the ketoximato group-containing silane used.

Further, in order to impart an appropriate extrudability to the composition before curing and to impart excellent mechanical properties to the rubber-like elastic body after curing, n of the component (A) is the same as the component (A). The viscosity at 23 ° C. is 20,000 cP or more, preferably 20,000 to 1,000,000 cP. When the viscosity of the component (A) is less than 20,000 cP, the stretchability of the rubber-like elastic body after curing is insufficient. On the other hand, when the viscosity exceeds 1,000,000 cP, it is difficult to obtain a uniform composition and the extrusion workability is deteriorated, which is not preferable. A particularly preferable viscosity is 20, from the viewpoint of balancing the properties required for the composition before and after curing.
It is in the range of 000 cP to 300,000 cP.

In the room-temperature-curable polyorganosiloxane composition which is curable without using a crosslinking agent, among the above-mentioned components (A), the component (A1), that is, a ketoximato group in which X is a hydrolyzable group is used. And p is an average of more than 1 (ie, an average of more than 2 X's in the molecule).
Are used as the base polymer,
X in the component (A1) serves as a crosslinking means, and the crosslinking reaction proceeds even without a crosslinking agent and cures to give a rubber-like elastic body.
By using such a base polymer, it is possible to stabilize the composition before curing and to provide excellent curability.

In the room-temperature-curable polyorganosiloxane composition of the type which is cured using a crosslinking agent, (A)
A crosslinked structure is formed by using the component (A2) as a component in combination with a crosslinking agent. As the component (A2), X is a hydroxyl group or a ketoximato group, and p is 1
(That is, having two X which are a hydroxyl group and / or a ketoximato group in the molecule) can be used.

As the crosslinking agent, a silicon compound having a silicon functional group for curing the composition by reacting with the silicon functional group X in the component (A) in the presence of water and a curing catalyst, and / or the same. A partially hydrolyzed condensate is used.

This cross-linking agent is, for example, represented by the following general formula: R ⁴ _4-q SiY _q (wherein, R ⁴ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other. , Y represents a hydrolyzable group, and q is a number exceeding 2 on average and 4 or less.).

As R ⁴ , a group similar to the organic group R ¹ directly bonded to the silicon atom of the component (A) can be exemplified, and because it is easily available and an excellent crosslinking reaction rate can be obtained. , Methyl group or vinyl group is preferred. Also,
Examples of the hydrolysis-reactive group Y include the ketoximato group mentioned as X existing in the terminal group of the component (A).

Examples of such crosslinking agents are methyltris (methylethylketoxime) silane, vinyltris (methylethylketoxime) silane, phenyltris (methylethylketoxime) silane, methyltris (dimethylketoxime) silane, tetrakis (methylethylketoxime) silane, Examples thereof include silane containing ketoximato group such as methyldi (methylethylketoxime) silane, vinyldi (methylethylketoxime) silane, phenyldi (methylethylketoxime) silane, methyldi (dimethylketoxime) silane and partial hydrolysates thereof. Among these, the silane in which q is 2 is 3 in q.
Alternatively, it is used in combination with a silane which is 4.

Considering that it is easy to synthesize and does not impair the storage stability of the composition, and gives a high crosslinking reaction rate and thus a high curing rate, among these crosslinking agents, methyltris (methylethylketoxime) silane,
It is preferable to use vinyltris (methylethylketoxime) silane, phenyltris (methylethylketoxime) silane and their partial hydrolysis-condensation products.

The amount of the cross-linking agent blended is usually 0.5 to 25 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts by weight of the component (A2). If the amount is less than 0.5 part by weight, crosslinking is not sufficiently performed, and only a cured product having a low hardness can be obtained, and the storage stability of the composition containing the crosslinking agent is poor. On the other hand, if it is blended in excess of 25 parts by weight, a part of it will separate from the system during storage, causing significant shrinkage during curing,
The physical properties of the obtained rubber-like elastic body deteriorate.

As the component (A), the above-mentioned (A1)
When X is a ketoximato group and p is more than 1 on average, curing can be basically performed without a cross-linking agent, as described above. In order to realize the mechanical properties of the obtained rubber-like elastic body in a well-balanced manner, it is preferable to use the above-mentioned crosslinking agent in combination. Further, it is more preferable to use a crosslinking agent in which the hydrolyzable group Y is the same as X. In this case, the compounding amount of the crosslinking agent is usually 0.1 to 100 parts by weight of the component (A1).
It is 25 parts by weight, preferably 0.3 to 10 parts by weight. If the amount is more than 25 parts by weight, the above-mentioned phenomenon occurs, which is not preferable.

In the present invention, in addition to the silicon-functional compound (ketoximato group-containing silane) having an unsubstituted monovalent hydrocarbon group as R ⁴ as enumerated above as specific examples, a substituted carbon Silanes having hydrogen groups may be used as part of the crosslinker.

Here, the substituted monovalent hydrocarbon group includes a substituted or unsubstituted amino group, an epoxy group, an isocyanato group, a (meth) acryloxy group, a mercapto group or an alkyl group substituted with a halogen atom. A phenyl group is exemplified. Examples of the substituted alkyl group include a substituted methyl group, a 3-substituted propyl group, a 4-substituted butyl group and the like, but a 3-substituted propyl group is preferable because of easy synthesis.

Examples of the silane having such a substituted hydrocarbon group include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltriisopropoxysilane and 3-aminopropyltriacetamidosilane. , N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N-
(2-Aminoethyl) -3-aminopropyltriethoxysilane, N-methyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N, N-dimethyl-3-aminopropyltrimethoxysilane Substituted or unsubstituted amino group-containing silane such as methoxysilane; 3-glycidoxytrimethoxysilane, 3
An epoxy group-containing silane such as glycidoxymethyldimethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane; an isocyanato group-containing silane such as 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropylmethyldimethoxysilane ; 3-
(Meth) acryloxy group-containing silane such as acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane; 3-mercaptopropyltrimethoxy Examples thereof include mercapto group-containing silanes such as silane; and halogen atom-containing silanes such as 3-chloropropyltrimethoxysilane.

Such substituted hydrocarbon group-containing silanes and vinyl group-containing silanes are carbon-functional silanes, and by blending them, the adhesiveness to various substrates when the composition is cured is improved. Can be made. In particular, it is preferable to use a substituted or unsubstituted aminoalkyl group-containing silane because of its effect of improving the curability and adhesiveness of the composition and its rapid expression.

Further, the silicon-functional polydiorganosiloxane having an average of more than 2 ketoximato groups as silicon functional groups in the molecule which is the component (A1) is a moisture barrier to a polydiorganosiloxane having silanol groups at both ends. It is possible to easily obtain by blending the ketoximatosilane below, at which time by blending the above-mentioned carbon functional silane and introducing a silicon functional group having a substituted hydrocarbon group, A composition having high strength and high extensibility and having excellent curability and adhesiveness can be obtained.

The amount of the carbon-functional silane compounded is preferably 0.05 to 25 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the component (A). If the amount is less than 0.05 parts by weight, the effect of improving the adhesiveness is small and the expression is slow. In addition, if the amount is more than 25 parts by weight, in addition to the above-mentioned problems, storage stability and workability are deteriorated, and a yellowing phenomenon occurs.

In the present invention, the curing catalyst of the component (B) is
X contained as a cross-linking means of the component (A) itself, and / or X of the component (A) and a cross-linking agent Y are reacted in the presence of water to form a cross-linked structure, and a rubber-like elastic body is obtained. It is a catalyst for obtaining. Examples of the component (B) include carboxylic acid metal salts such as iron octoate, manganese octoate, zinc octoate, tin naphthate, tin caprylate and tin oleate; dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin dioleate. , Organotin compounds such as diphenyltin diacetate, dibutyltin oxide, dibutyltin dimethoxide, dibutylbis (triethoxysiloxy) tin, dioctyltin dilaurate; tetraethoxytitanium, tetrapropoxytitanium,
Alkoxytitaniums such as tetrabutoxytitanium, 1,3-propoxytitanium bis (ethylacetylacetate); organoaluminums such as aluminum trisacetylacetonate, aluminum trisethylacetoacetate, diisopropoxyaluminum ethylacetoacetate, triethoxyaluminum; Examples thereof include organic zirconium compounds such as zirconium tetraacetylacetonate, tetraisopropoxyzirconium, tetrabutoxyzirconium, tributoxyzirconium acetylacetonate, and tributoxyzirconium stearate. Organotin compounds and alkoxytitaniums are preferable because they have a large catalytic ability even in the presence of a trace amount.

The blending amount of the component (B) is 100 parts of the component (A).
0.01 to 10 parts by weight, preferably 0.0
5 to 5 parts by weight. If it is less than 0.01 parts by weight, it does not sufficiently act as a curing catalyst, and it not only takes a long time to cure, but also the curing in the deep part of the rubber layer far from the contact surface with air becomes insufficient, and conversely When the amount exceeds the range, there is no effect commensurate with the blending amount, which is meaningless and economically unfavorable.

The surface-treated calcium carbonate of the component (C) of the present invention imparts an appropriate fluidity to the composition of the present invention before curing, and after curing, the obtained rubber-like elastic body, for example, a sealing material. , It provides the high mechanical strength required for adhesives, in-situ molded gaskets, etc.

This surface-treated calcium carbonate can be obtained by surface-treating calcium carbonate such as precipitated calcium carbonate with a fatty acid and a fatty acid alkali metal salt by a conventional method.

The calcium carbonate to be used may be, for example, precipitated calcium carbonate obtained by conducting carbon dioxide gas in a water slurry of slaked lime, or solution-processed calcium carbonate produced by reacting a carbonate solution with a calcium salt solution. is a selectable, in order to obtain a high thixotropy, BET specific surface area of ^{5m 2} / ^g~120m 2 / g, more preferably 1
Calcium carbonate 0m ² / g~30m ² / g is used. If the BET specific surface area is less than 5 m ² / g, it is difficult to impart high viscosity, and if it exceeds 120 m ² / g, it is necessary to increase the amount of the surface treatment agent and the cost becomes too high.

The average particle size is 0.03 to 0.15 μm.
m and the bulk density specified in JIS 5101 is 2
By using 80 ml / 100 g or more of calcium carbonate, it is possible to exhibit excellent extensibility while maintaining excellent mechanical strength. The bulk density of calcium carbonate is 2
When the amount is less than 80 ml / 100 g, although high extensibility is obtained, mechanical strength is insufficient and problems such as being unable to withstand sudden movement of the adherend occur. When the average particle size of calcium carbonate exceeds 0.15 μm, it is difficult to obtain desired mechanical strength, and 0.03 μm is obtained.
If it is less than μm, the workability of the composition before curing is significantly reduced, which is not preferable.

As the linear fatty acid used in the present invention, either saturated fatty acid or unsaturated fatty acid can be used, but from the viewpoint of storage stability and thixotropy, it is desirable that the linear fatty acid has 8 or more carbon atoms. .

Specific examples thereof include saturated fatty acids such as caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid and aragic acid, and unsaturated fatty acids such as oleic acid, elaidic acid, linoleic acid and ricinoleic acid. .
Stearic acid, oleic acid, palmitic acid, and linoleic acid are preferable, and stearic acid is more preferably used in terms of strength, in order to obtain a composition that is inexpensive and has excellent extensibility.

The amount of linear fatty acid or its alkali metal salt used for such surface treatment is preferably 2.7 to 4.5% by weight with respect to calcium carbonate. When the amount of the surface treatment agent is less than 2.7% by weight, the treated coated surface is not uniform and the workability such as ejection and sagging is deteriorated, the adhesiveness is deteriorated, and the curing stability is improved. Does not appear enough. On the other hand, if it exceeds 4.5% by weight, an excessive amount causes a decrease in extensibility, which is not preferable.

In the present invention, the compounding amount of the surface-treated calcium carbonate as the component (C) is 30 to 200 parts by weight, more preferably 50 to 50 parts by weight, relative to 100 parts by weight of the component (A).
It is in the range of 150 parts by weight. If it is less than 30 parts by weight, the effect of improving the mechanical properties due to the addition of calcium carbonate hardly appears, and if it exceeds 200 parts by weight, the modulus of the cured product becomes large and the elongation at break becomes small, which is not preferable. .

Further, the composition of the present invention contains a pigment, a thixotropy-imparting agent, a viscosity modifier for improving extrusion workability, an ultraviolet absorber, a fungicide, depending on the purpose.
Various additives such as a heat resistance improver and a flame retardant may be added.

The composition of the present invention can be obtained by mixing all the above components and, if necessary, various additives in a state in which moisture is blocked. The obtained composition can be used as a so-called one-pack type room temperature curable composition which is stored as it is in a closed container and is cured only when exposed to moisture in the air during use. In addition, the composition of the present invention is prepared, for example, as a composition in which a cross-linking agent and a curing catalyst are separated, and appropriately stored in 2 to 3 separate containers, which are mixed at the time of use, a so-called multi-pack type It can also be used as a room temperature curable composition.

The room-temperature-curable polyorganosiloxane composition obtained according to the present invention is stable under a sealed condition in the absence of moisture, and when exposed to moisture in the air,
It cures at room temperature to give a rubber-like elastic body. In particular, the present invention is
Provided is a room-temperature-curable polyorganosiloxane which has a fast curing rate, a cured product having a very large elongation and a high tensile strength at the time of elongation.

[0049]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to Examples, but the present invention is not limited to the following Examples. In the examples, “parts” means “parts by weight”, and all physical properties such as viscosity are values at 23 ° C. and relative humidity of 50%.

Example 1 100 parts of α, ω-dihydroxypolydimethylsiloxane having a viscosity of 40,000 cSt was treated with stearic acid in a proportion of 4.0% to prepare synthetic calcium carbonate (average particle size 0.05 μm, BET specific surface area). 20 m ² / g, bulk density 3
50 ml / 100 g) 100 parts, and polydimethylsiloxane 3 having a viscosity of 100 cP with a terminal blocked with a methyl group 3
0 part was blended and kneaded. Next, to this, 7 parts of methyltris (methylethylketoxime) silane, 3 parts of vinyltris (methylethylketoxime) silane, 3- (2-
Aminoethyl) propyltrimethoxysilane (1 part) and dibutyltin dilaurate (0.1 part) were added in a moisture-proof state and uniformly mixed to obtain a polyorganosiloxane composition.

Example 2 100 parts of α, ω-dihydroxypolydimethylsiloxane having a viscosity of 100,000 cP was treated with stearic acid at a ratio of 3.0% to prepare synthetic calcium carbonate (average particle diameter 0.07 μm, BET specific surface area). 17m ² / g, bulk density 3
120 parts of 50 ml / 100 g) and 35 parts of polydimethylsiloxane having a viscosity of 100 cP with a terminal blocked with a methyl group were mixed and kneaded. After that, under the condition of moisture blocking,
Phenyltris (methylethylketoxime) silane 10
Part, 3- (2-aminoethyl) propyltrimethoxysilane (1 part) and dibutyltin dilaurate (0.08 part) were further added and mixed uniformly to obtain a polyorganosiloxane composition.

Example 3 100 parts of α, ω-dihydroxypolydimethylsiloxane having a viscosity of 40,000 cP was added with stearic acid (45
%), Oleic acid (30%), palmitic acid (25%)
Synthetic calcium carbonate (average particle diameter 0.05 μm, BET specific surface area 16.0 m ² / g, bulk density 300 ml / 100 g) treated with the mixture of (treatment agent ratio 2.7%) 8
0 parts and 35 parts of polydimethylsiloxane having a viscosity of 100 cP in which the terminal was blocked with a methyl group were mixed and kneaded. Then, in a state of being protected from moisture, 7 parts of methyltris (methylethylketoxime) silane, 3 parts of vinyltris (methylethylketoxime) silane, 1 part of 3-aminopropyltriethoxysilane and 1.0 part of dibutyltin dilaurate.
One part was further added and mixed uniformly to obtain a polyorganosiloxane composition.

Example 4 As calcium carbonate, average particle size 0.05 μm, BE
T specific surface area 16.0 m ^Two/ G, bulk density 350ml / 10
The amount of surface treatment agent is 2.0%.
Otherwise in the same manner as in Example 1, the polyorganosiloxane group
I got a product.

Comparative Example 1 Calcium carbonate having an average particle diameter of 0.08 μm and B
ET specific surface area of 16.0 m ² / g, bulk density of 230 ml
A polyorganosiloxane composition was obtained in the same manner as in Example 1 except that the composition of 100 g / 100 g was used.

Comparative Example 2 Calcium carbonate having an average particle size of 0.17 μm and B
ET specific surface area is 9.0 m ² / g, bulk density is 155 ml /
A polyorganosiloxane composition was obtained in the same manner as in Example 3 except that 100 g was used.

Comparative Example 3 A polyorganosiloxane composition was obtained in the same manner as in Example 1 except that the surface treating agent for calcium carbonate was rosin acid.

Comparative Example 4 Instead of using 7 parts of methyltris (methylethylketoxime) silane and 3 parts of vinyltris (methylethylketoxime) silane as a crosslinking agent, 3.2 parts of methyltrimethoxysilane and 1.4 parts of vinyltrimethoxysilane were used.
A polyorganosiloxane composition was obtained in the same manner as in Example 1 except that parts were used.

Next, with respect to the polyorganosiloxane compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 4 and sealed and stored, as follows, touch dry time, physical properties and storage stability were obtained. The adhesiveness was measured and evaluated. The results of these measurements are shown in Table 1.

(A) Drying time to the touch: The composition was kept at 23 ° C. for 5
After extruding in an atmosphere of 0% RH, the time until contacting the surface with a finger and confirming that it was in a dry state was measured.

(B) Physical properties: The composition was extruded into a sheet having a thickness of 2 mm, and the obtained sheet was heated at 23 ° C. and 50%.
It was left standing at RH for 168 hours to be cured by moisture in the air, and the physical properties of the cured product were measured according to JIS K6301.

(C) Storage stability: The composition was placed in a container protected from moisture and heated at 70 ° C. for 5 days, and then the touch dry time was measured in an atmosphere of 23 ° C. and 50% RH. Also, extruded into a sheet shape with a thickness of 2 mm, and this was 23 ° C, 50%
Let stand at RH for 168 hours to cure with moisture in the air, and set the physical properties of the cured product to JISK as in (b) above.
6301.

(D) Adhesiveness: The composition was applied onto various adhesive members, a glass cloth having a width of 25 mm was laid thereon, and the composition was adjusted to have a thickness of 2 mm. The product was applied to a thickness of about 2 mm. Then, it was left standing at 23 ° C. and 50% RH for 168 hours, cured by moisture in the air, and its adhesive strength was measured by an autograph (manufactured by Shimadzu Corporation). In addition, the cohesive failure rate of the adhesive was measured.

[0063]

[Table 1]

As can be seen from Table 1, the polyorganosiloxane compositions prepared in Examples 1 to 4 have excellent storage stability, are stable under a sealed condition without moisture, and have a moisture content in the air. It only cures at room temperature when it comes into contact with it, giving rise to a rubber-like elastic material with excellent physical properties. Further, compared with the cured products obtained in Comparative Examples 1 to 4, the cured product has a large elongation and has an extremely large tensile strength at the time of elongation, and has excellent adhesiveness to various materials, particularly metal materials. .

[0065]

As is apparent from the above description, the room-temperature-curable polyorganosiloxane composition of the present invention is stable under sealed conditions without moisture, and can be stored at room temperature by contact with moisture in the air. Curing yields a rubber-like elastomer with good mechanical properties and excellent adhesion. Also,
Curing is fast, and the cured product has a very large elongation and a high tensile strength when stretched.

Therefore, the room-temperature-curable polyorganosiloxane of the present invention is suitable as an elastic adhesive particularly for products requiring rapid stretchability such as airbags.

Claims (5)

[Claims] 1. An (A) (A1) molecule having an average of more than 2 ketoximato groups as silicon functional groups,
A silicon-functional polydiorganosiloxane having a viscosity of 20,000 cP or more at 0 ° C., and / or (A
2) A room temperature curable polyorganosiloxane composition comprising a silicon-functional polydiorganosiloxane having two or more silanol groups and / or ketoximato groups in the molecule and a silane having a ketoximato group as a cross-linking agent, A) 0.01 to 10 parts by weight of a curing catalyst (B), and (C) to 100 parts by weight of polydiorganosiloxane.
The average particle size is 0.03 to 0.15 μm and JIS 51
Calcium carbonate 30 to 20 having a bulk density defined by 01 of 280 ml / 100 g or more and surface-treated with a saturated or unsaturated linear fatty acid or an alkali metal salt thereof.
A room-temperature-curable polyorganosiloxane composition, characterized by containing 0 parts by weight each. 2. The room temperature-curable polyorgano according to claim 1, wherein the crosslinking agent contains silane having a substituted hydrocarbon group in a proportion of 0.05 to 25 parts by weight as at least a part of the crosslinking agent. Siloxane composition. 3. The linear fatty acid or alkali metal salt thereof is at least one selected from stearic acid, oleic acid, palmitic acid, and alkali metal salts thereof.
The room temperature curable polyorganosiloxane composition according to claim 1 or 2, which is a seed. 4. The room temperature curable polyorganosiloxane composition according to claim 1, wherein the calcium carbonate has a BET specific surface area of 10 to 30 m ² / g. 5. The surface treatment amount of the linear fatty acid or its alkali metal salt is 2.
The room-temperature-curable polyorganosiloxane composition according to any one of claims 1 to 4, wherein the proportion is 7 to 4.5% by weight.