JP2006182935A - Room temperature-curing polyorganosiloxane composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a room temperature-curing polyorganosiloxane composition having further improved flame retardance and improved adhesiveness, etc., to a slightly adhesive member such as rubber and an engineering plastic. <P>SOLUTION: The room temperature-curing polyorganosiloxane composition comprises (A) a polyorganosiloxane composed of (A1) a silicon-functional polydiorganosiloxane and/or (A2) a silicon-functional polydiorganosiloxane and a cross-linking agent. The room temperature-curing polyorganosiloxane composition comprises (A) 100 pts.wt. of the polyorganosiloxane, (B) 0.5-15 pts.wt. of a curing catalyst and (C) 1.0-100 pts.wt. of zinc carbonate having 30-35% weight loss by evolution of gaseous carbon dioxide and ≥33% weight loss by heating, respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a room temperature curable polyorganosiloxane composition. More specifically, the present invention is stable under sealing conditions without moisture, and cures at room temperature by contact with moisture in the air to form a rubbery elastic body. The resulting room temperature curable polyorganosiloxane composition. In particular, the present invention relates to a room temperature curable polyorganosiloxane composition having excellent flame retardancy and good curability and storage stability.

  Among the polyorganosiloxane compositions that cure at room temperature to produce rubbery elastic bodies, the room temperature curable polyorganosiloxane composition of the type that undergoes a curing reaction by contact with moisture in the air is the main body immediately before use. The base polymer, cross-linking agent, catalyst, etc. are not weighed or mixed, and there are no mistakes in blending. It is widely used as an elastic adhesive and coating material, and as a sealing material for buildings.

  In general, such a composition is composed of a silanol group-terminated polydiorganosiloxane whose molecular terminal is blocked with a hydroxyl group, and a crosslinking agent having more than two hydrolyzable groups in the molecule. Upon curing, carboxylic acid such as acetic acid, organic amine, amide, organic hydroxylamine, oxime compound, alcohol, acetone and the like are released according to the kind of the crosslinking agent. In particular, when a room temperature-curable polyorganosiloxane composition is cured into a rubbery elastic body for the purpose of an adhesive, a coating material, etc., a deoxime type, a deacetone type, a dealcohol type type should be used. There are many.

  On the other hand, one-packaging type (one-component type) room temperature curable compositions comprising polyorganosiloxanes having alkoxy groups bonded to terminal silicon atoms, alkoxysilanes, and curing catalysts have recently been used. . A polyorganosiloxane in which an alkoxy group is bonded to a silicon atom at a terminal is characterized by good storage stability and quick curing compared to a polyorganosiloxane having a terminal hydroxyl group. Such a fast curable room temperature curable polyorganosiloxane composition is particularly useful as an adhesive or a coating material.

  In recent years, safety of products has been regarded as important in various fields including electric appliances, and further improvement in flame retardancy and heat resistance is desired. Under such circumstances, there is an increasing demand for a flame retardant sealing material.

  Conventionally, many kinds of materials have been found for imparting silicone-based polymer flame retardancy. Examples of flame retardant materials include fillers such as aluminum hydroxide, zinc carbonate, magnesium carbonate, titanium oxide, and silicon dioxide, and small amounts of noble metal compounds such as platinum compounds, triazoles, carboxylic acid amides, and ammonium chloride. Additives have been proposed.

Among these flame retardant imparting materials, zinc carbonate is useful in terms of economy and flame retardancy imparting effects. However, zinc carbonate, which is generally blended as a filler,
It has a structural formula: 2ZnCO ₃ .3Zn (OH) ₂ .H ₂ O, and the storage stability is lowered due to the contained moisture. Therefore, even if it performs dehydration by heating, there is a problem that the storage stability cannot be improved sufficiently.

  In order to solve such problems, the inventors have conducted intensive studies. As a result, zinc carbonate that does not contain hydroxyl groups and water of crystallization, has high purity and flame retardancy, and efficiently generates carbon dioxide is used. Therefore, a composition having excellent flame retardancy and excellent curability and storage stability was proposed. (For example, see Patent Document 1)

  However, generally, when such a filler having an effect of imparting flame retardancy is blended with the sealant, the cured sealant is likely to be peeled off or the thin layer is broken at the adhesive interface, and the adhesiveness is likely to be lowered. There was a problem. In particular, rubber used for so-called wedge-shaped members used for positioning of deflection yokes of television CRTs for electrical and electronic applications, engineering plastics such as polybutylene terephthalate resin used for bases, In addition, the adhesion to heat-resistant and flame-retardant rubbers used in OA equipment such as personal computers was insufficient.

In addition, the required value for the level of flame retardancy is increasing year by year, and the cured product of the sealing agent used for the above-described application is required to have elasticity that can follow a change due to contraction of the member to some extent. There were many issues.
JP 2000-38507 A

  The present invention has been made to solve these problems, and further improves the flame retardancy, and adheres to difficult-to-adhere members such as rubber and engineering plastics, and the follow-up ability of the sealant to changes in the members. It is an object to provide an improved room temperature curable polyorganosiloxane composition.

  As a result of diligent research to solve the above problems, the present inventors have improved adhesion to rubber and engineering plastics, which are difficult to adhere, by using high-purity zinc carbonate having a relatively large particle size. As a result, the present invention has been completed.

  That is, the room temperature curable polyorganosiloxane composition of the present invention comprises (A) (A1) a silicon functional polydiorganosiloxane having an average number of hydrolyzable groups exceeding 2 as silicon functional groups in the molecule, and / or Or (A2) a room temperature curable polyorganosiloxane composition comprising a polyorganosiloxane comprising a silicon functional polydiorganosiloxane having two or more silicon functional groups in the molecule and a cross-linking agent, (B) 0.5 to 15 parts by weight of the curing catalyst with respect to 100 parts by weight of the organosiloxane, and (C) the weight reduction rate due to heating is 33 to 36%, and the weight due to the generation of carbon dioxide during thermal decomposition It contains 1.0 to 100 parts by weight of zinc carbonate having a reduction rate of 30 to 35%.

  The room temperature curable polyorganosiloxane composition of the present invention is stable under sealing conditions in the absence of moisture, and is particularly excellent in storage stability. And it contacts the water | moisture content in air, and it hardens | cures at room temperature, The rubber-like elastic body which has the outstanding flame retardance and adhesiveness is obtained.

  Hereinafter, embodiments of the present invention will be described.

  Embodiments of the room temperature curable polyorganosiloxane composition according to the present invention include (A) (A1) a silicon functional polydiorganosiloxane having an average of more than two hydrolyzable groups as silicon functional groups in the molecule, And / or (A2) a room temperature curable polyorganosiloxane composition comprising a polyorganosiloxane comprising a silicon functional polydiorganosiloxane having two or more silicon functional groups in the molecule and a crosslinking agent, comprising: (B) 0.5 to 15 parts by weight of the curing catalyst with respect to 100 parts by weight of the polyorganosiloxane, and (C) the weight reduction rate due to heating is 33% or more, and the weight due to the generation of carbon dioxide during thermal decomposition 1.0 to 100 parts by weight of zinc carbonate having a reduction rate of 30 to 35% is contained.

  In the present invention, the (A) polyorganosiloxane used as the base polymer comprises a combination of the (A1) component having a silicon functional group and / or the (A2) component and a crosslinking agent. In itself, a crosslinking reaction is caused by the catalytic action of the component (B) described later to cure. Further, the combination of the component (A2) and the crosslinking agent cures by causing a crosslinking reaction between the component (A2) and the crosslinking agent by the catalytic action of the component (B). In either case, the reaction is a hydrolysis reaction and a subsequent condensation reaction, and the reaction proceeds in the presence of moisture in the air.

で表される実質的に直鎖状のポリオルガノシロキサンである。 The component (A1) and the component (A2) used in the embodiment of the present invention typically have the following general formula:

Is a substantially linear polyorganosiloxane.

In the formula, R ¹ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same as or different from each other, and R ² represents —ZSiR ³ _3-p X _p . Here, Z represents oxygen and / or a divalent hydrocarbon group, R ³ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same as or different from each other, and X represents a hydrolyzable group. A certain alkoxy group is represented, and p is an integer of 1 to 3. N is a number that makes the viscosity at 25 ° C. of the component (A1) or component (A2), which is the component (A), 20 to 1,000,000 mPa · s.

Thus, the terminal group R ² is a silicon functional siloxy unit having at least one hydrolyzable group X which is a silicon functional group, and the (A1) component and the (A2) component are respectively present at both ends of the molecule. It has at least one hydrolyzable group X.

R ¹ is a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other. R ¹ is an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a deseal group or a dodeceal group; an alkenyl group such as a vinyl group or an allyl group; a phenyl group And aryl groups such as tolyl group and xylyl group; aralkyl groups such as 2-phenylethyl group and 2-phenylpropyl group are exemplified, and a part of hydrogen atoms of these hydrocarbon groups is another atom or group. Substituted with, i.e., halogenated alkyl groups such as chloromethyl, 3-chloropropyl, 3,3,3-trifluoropropyl; substituted carbons such as cyanoalkyl such as 3-cyanopropyl A hydrogen group is illustrated. It is easy to synthesize, and the component (A) has a low viscosity with respect to the molecular weight, gives good extrudability to the composition before curing, and gives good physical properties to the composition after curing. Therefore, 85% or more of all organic groups are preferably methyl groups, and substantially all organic groups are more preferably methyl groups.

On the other hand, when imparting heat resistance, radiation resistance, cold resistance or transparency to the composition, a necessary amount of phenyl group as part of R ¹ , when imparting oil resistance and solvent resistance, In the case where a 3,3,3-trifluoropropyl group or 3-cyanopropyl group is provided as a part of R ¹ or a surface having paintability is provided, a long chain alkyl group or aralkyl is provided as a part of R ^1. A group can be arbitrarily selected depending on the purpose, for example, in combination with a methyl group.

R ³ bonded to the silicon atom in the end groups R ² is a monovalent hydrocarbon group or different even though good, and R ¹ and different they may also be substituted or unsubstituted at the same identical to one another, R ¹ The same thing is illustrated. A methyl group or a vinyl group is preferred because synthesis is easy and the reactivity of the hydrolyzable group X is excellent. 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. In view of easy synthesis, an oxygen atom and an ethylene group are preferable, and an oxygen atom is particularly preferable.

X is a silicon functional group present in at least one terminal group R ² , that is, an alkoxy group that is a hydrolyzable group. Examples of such X include an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group; a substituted alkoxy group such as a 2-methoxyethoxy group and a 2-ethoxyethoxy group; an enoxy group such as an isopropenoxy group, Examples include a ketoximato group such as a methyl ethyl ketoxime group, an acetoxy group, and the like, which may be the same or different. Alkoxy groups and ketoximato groups are preferred because of their ease of synthesis, physical properties of the composition before curing, stability during storage, curability, economy, and use in a wide range of applications.

Furthermore, the number p of silicon functional groups X in the terminal group R ² is preferably 1 to 3. Among them, the component (A2) used in the room temperature curable polyorganosiloxane composition containing the crosslinking agent is easy to synthesize and used in combination with various crosslinking agents, so that X is a hydroxyl group and p is 1. Is preferred. Such a silicon-functional polydiorganosiloxane is obtained by ring-opening polymerization or ring-opening copolymerization of a cyclic diorganosiloxane low monomer such as octamethylcyclosiloxane in the presence of water with an acidic catalyst or an alkaline catalyst, It can be obtained by introducing a hydroxyl group bonded to a silicon atom into the terminal of the obtained linear polydiorganosiloxane.

A compound in which X is a hydrolyzable group can be synthesized, for example, by condensing a silane having two or more arbitrary hydrolyzable groups to a polyorganosiloxane having a hydroxyl group at the terminal. In this case, since one hydrolyzable group possessed by the silane is consumed by the condensation reaction, the number p of X in the terminal group R ² of the polyorganosilosan obtained by the reaction contains the hydrolyzable group used. One less than the number of X that silane has.

  In addition, in order to give moderate extrudability to the composition before curing and to give excellent mechanical properties to the rubber-like elastic body after curing, the component (A) (that is, the component (A1) or the component (A2) N in the general formula representing) is selected so that the viscosity of the component (A) at 25 ° C. is 20 to 1,000,000 mPa · s. If the viscosity of the component (A) is less than 20 mPa · s, the rubber-like elastic body after curing is not sufficiently stretched. On the other hand, if it exceeds 1,000,000 mPa · s, it is difficult to obtain a uniform composition and extrusion workability Also decreases. In order to harmonize the properties required for the composition before and after curing in a well-balanced manner, the particularly preferred viscosity is in the range of 500 to 200,000 mPa · s.

  In a room temperature curable polyorganosiloxane composition that cures without using a crosslinking agent, X in the component (A), that is, the component (A1) serves as a crosslinking means, and the crosslinking reaction proceeds without a crosslinking agent, Curing produces a rubbery elastic body. Preferred X is an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, or a butoxy group; an acyloxy group such as an acetoxy group; and a ketoximato group such as a methylethylketoxime group. By using such a component (A1) as a base polymer, the composition before curing is stabilized and excellent curability is obtained.

  In addition, in a room temperature curable polyorganosiloxane composition of a type that is cured using a crosslinking agent, a crosslinked structure is formed by using the component (A2) in combination with the crosslinking agent as the component (A). As the component (A2), one in which X is a hydroxyl group or p is 1 (that is, in the molecule having a hydroxyl group and / or two hydrolyzable groups similar to the above) is used. it can.

  As a crosslinking agent, a silicon compound having a silicon functional group for reacting with the silicon functional group X in the component (A) (that is, the component (A2)) in the presence of water and a curing catalyst to cure the composition And / or partial hydrolysis condensates thereof.

This crosslinking agent has the general formula: R ⁴ _4-q SiY _q
(In the formula, 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 an average of more than 2 and 4 or less. ).

As R ⁴ , the same group as the organic group R ¹ directly bonded to the silicon atom of the component (A) can be exemplified, and since it is easily available and has an excellent crosslinking reaction rate, a methyl group or A vinyl group is preferred. Examples of the hydrolyzable reactive group Y are the same as those exemplified as X existing in the terminal group of the component (A).

  Examples of such crosslinkers include tetramethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, tetrapropoxy. Alkoxy group-containing compounds such as silane, tetraisopropoxysilane and partial hydrolysis condensates thereof; tetrakis (2-ethoxyethoxy) silane, methyltris (2-methoxyethoxy) silane, vinyl (2-ethoxyethoxy) silane, phenyl Substituted alkoxy group-containing compounds such as tris (2-methoxyethoxy) silane and partial hydrolysis condensates thereof; methyltriisopropenoxysilane, vinyltriisopropenoxysilane, phenyltrii Enoxy group-containing compounds such as propenoxysilane, dimethyldiisopropenoxysilane, methylvinyldiisopropenoxysilane and partial hydrolysis condensates thereof; methyltris (methylethylketoxime) silane, vinyltris (methylethylketoxime) silane and the like Examples thereof include ketoximato group-containing compounds such as partial hydrolysates; methyltriacetoxysilane and acyloxy group-containing compounds such as partial hydrolysates thereof. Of these, silane having q of 2 is used in combination with silane having q of 3 or 4.

  Among these cross-linking agents, tetramethoxysilane, tetraethoxysilane, methyltrimethyl are used because they are easy to synthesize, do not impair the storage stability of the composition, and provide a high crosslinking reaction rate, that is, a high curing rate. Use of methoxysilane, vinyltrimethoxysilane, methyltris (isopropenoxy) silane, vinyltris (isopropenoxy) silane, methyltris (methylethylketoxime) silane, vinyltris (methylethylketoxime) silane, methyltriacetoxysilane and partial hydrolysis condensates thereof preferable.

  The amount of the crosslinking agent is 0.5 to 25 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts by weight of component (A2). If the amount is less than 0.5 part by weight, crosslinking is not sufficiently performed, and not only a cured product having low hardness is obtained, but also the storage stability of the composition containing the crosslinking agent is poor. On the other hand, when it exceeds 25 parts by weight, not only a part of the cross-linking agent is separated from the system during storage, but also significant shrinkage occurs during curing, and the physical properties of the resulting rubbery elastic body are lowered.

  As (A) component, when X which is the above-described (A1) component is a hydrolyzable group and p exceeds an average of 1, as described above, curing is possible without a crosslinking agent. Even in such a case, it is preferable to use the above-mentioned crosslinking agent together in order to realize a good balance between the curability of the composition and the mechanical properties of the rubber-like elastic body obtained by curing. It is more preferable to use a crosslinking agent having the same hydrolyzable group Y. In this case, the amount of the crosslinking agent is 0.1 to 25 parts by weight, preferably 0.3 to 10 parts by weight, based on 100 parts by weight of component (A1). When the amount exceeds 25 parts by weight, the phenomenon described above is generated, which is not preferable.

In the embodiment of the present invention, the carbon functionality having a substituted monovalent hydrocarbon group in addition to the silicon functional compound having a monovalent hydrocarbon group as R ⁴ as listed in the specific examples above. These similar compounds may be used as part or all of the crosslinking agent. Examples of such R ⁴ include a substituted or unsubstituted amino group, epoxy group, isocyanato group, (meth) acryloxy group, mercapto group, or an alkyl group substituted with a halogen atom or a phenyl group. Examples of the substituted alkyl group include a substituted methyl group, a 3-substituted propyl group, and a 4-substituted butyl group, but a 3-substituted propyl group is preferable because of easy synthesis.

Examples of the compound having R ⁴ include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltriisopropoxysilane, 3-aminopropyltriacetamidosilane, N- (2-amino Ethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, N-methyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxy Silane, substituted or unsubstituted amino group-containing silane such as N, N-dimethyl-3-aminopropyltrimethoxysilane; 3-glycidoxytrimethoxysilane, 3-glycidoxymethyldimethoxysilane, 3,4-epoxy Of cyclohexylethyltrimethoxysilane Such epoxy group-containing silanes; isocyanato group-containing silanes such as 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropylmethyldimethoxysilane; 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3 (Meth) acryloxy group-containing silanes such as acryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane; mercapto group-containing silanes such as 3-mercaptopropyltrimethoxysilane; and 3-chloropropyltrimethoxysilane Such halogen atom-containing silanes are exemplified. Such substituted hydrocarbon group-containing silanes and the above-mentioned vinyl group-containing silanes are carbon-functional silanes, and by adding them, the adhesion to various substrates when the composition is cured is improved. Can do.

  Of these, it is preferable to use a substituted or unsubstituted aminoalkyl group-containing silane because of its high effect of improving the curability and adhesiveness of the composition and its rapid development. From this point of view, those having a primary amino group tend to easily burn because of the large shift to the surface of the sealant during the curing of the composition. Accordingly, those having a secondary amino group or a tertiary amino group are preferred. Examples of such hydrocarbon group-containing silanes include N-methyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, and N, N-dimethyl-3-aminopropyltrimethoxysilane. There are various substituted amino group-containing silanes.

  Also, the hydrogen atom part of the amino group of an unsubstituted amino group-containing silane such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltriisopropoxysilane, and 3-aminopropyltriacetamidosilane More preferably, is substituted with a hydrolyzable group-containing silyl group such as an alkyl group and / or an alkoxy group. Examples of such substituted amino group-containing silanes include N- (trimethoxysilyl) -3-aminopropyltrimethoxysilane and N- (trimethylsilyl) -3-aminopropyltriethoxysilane. Those in which the hydrogen atom part of the amino group is substituted with a silyl group also serve as a storage stabilizer when an organotin compound is used as the curing catalyst.

  The amount of the carbon-functional silane described above is preferably 0.05 to 25 parts by weight, more preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the component (A). If it is less than 0.05 part by weight, the effect of improving the adhesiveness is small and the onset thereof is slow. In addition, when it exceeds 25 parts by weight, it tends to cause separation of a liquid material such as a crosslinking agent during storage of the composition in a container, and the cured product tends to shrink when the composition is cured. In addition to causing harmful effects, workability is deteriorated and yellowing occurs.

  In the embodiment of the present invention, the component (B) contains X contained in itself as a crosslinking means for the component (A), and / or X of the component (A) and the crosslinking agent Y, and the presence of moisture. It is a curing catalyst for obtaining a rubber-like elastic body by reacting downward to form a crosslinked structure.

  Examples of the component (B) include iron octoate, manganese octoate, zinc octoate, tin naphthate, tin caprylate, tin oleate and carboxylic acid metal salts; dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin dioleate Organic tin compounds such as diphenyltin diacetate, dibutyltin oxide, dibutyltin dimethoxide, dibutylbis (triethoxysiloxy) tin, dioctyltin dilaurate; tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, 1,3-propoxytitaniumbis ( Alkoxytitanium such as ethyl acetylacetate; aluminum trisacetylacetonate, aluminum trisethylacetoacetate, dii Organic aluminum compounds such as propoxyaluminum ethyl acetoacetate and triethoxyaluminum; organic zirconium compounds such as zirconium tetraacetylacetonate, tetraisopropoxyzirconium, tetrabutoxyzirconium, tributoxyzirconium acetylacetonate, and tributoxyzirconium stearate Is done.

  Organotin compounds and alkoxy titaniums are preferred because they have a large catalytic ability in a small amount. That is, an organotin compound is more preferable because it has a large catalytic effect in the presence of a small amount, is excellent in compatibility, and has little influence of coloring or the like. Moreover, alkoxy titanium is more preferable from the point of a flame retardance and the elastic characteristic of the hardened | cured material obtained.

  The blending amount of the curing catalyst as the component (B) is 0.02 to 10 parts by weight, preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the component (A). When the blending amount of the component (B) is less than 0.02 parts by weight, it does not act sufficiently as a curing catalyst, and not only takes a long time for curing, but also cures particularly in the deep part of the rubber layer far from the contact surface with air. It becomes insufficient. When the blending amount of the component (B) exceeds 10 parts by weight, not only an effect commensurate with the blending amount cannot be obtained, but also flame retardancy is adversely affected, resulting in an economical disadvantage.

  In the embodiment of the present invention, the component (C), zinc carbonate, has a weight reduction rate of 33 to 36% due to heating (for example, heating in thermogravimetry (TG)), and is due to the generation of carbon dioxide during thermal decomposition. A weight reduction rate is 30 to 35%, and a carbon dioxide gas generation amount per unit weight is large. In thermogravimetry (TG), since zinc carbonate begins to decompose from a temperature of about 130 ° C, the temperature is gradually raised from room temperature (25 ° C) and heated to 500 ° C. Is measured. The gas generated during pyrolysis is measured by a quantitative method using GC-MS and a weight method such as weighing the dissolved gas in an aqueous alkaline solution.

In general, zinc carbonate blended as a filler for silicone rubber is basic zinc carbonate (transparent zinc white) obtained by a wet process, and is represented by the chemical formula: 2ZnCO ₃ .3Zn (OH) ₂ .H ₂ O. The In such zinc carbonate (basic zinc carbonate), the weight reduction rate in TG is around 28%, and the weight reduction rate due to the generation of carbon dioxide during thermal decomposition is about 15 to 16%. On the other hand, the zinc carbonate used as the component (C) in the embodiment of the present invention has a weight reduction rate of 33 to 36%, more preferably 34 to 36% in TG, and carbon dioxide gas during pyrolysis. The weight reduction rate due to generation is 30 to 35%. Moreover, the weight loss rate in 105 degreeC x 3 hour heating conditions used as the standard of the amount of crystallization water and the amount of adsorption | suction moisture is 0.1 to 0.2 weight%.

From these physical property values, it can be said that the component (C) used in the embodiment of the present invention is zinc carbonate having a high purity represented by the chemical formula: ZnCO ₃ . According to XRF (X-ray fluorescence analysis) for Zn, the purity is 95% or more. In addition, since the above-mentioned normal zinc carbonate (basic zinc carbonate) contains crystallization water and has a large amount of adsorbed water, the weight loss rate in heating at 105 ° C. for 3 hours is about 2-3%.

  Furthermore, as the (C) zinc carbonate of the embodiment of the present invention, the average particle diameter is 3.0 to 8.0 μm as measured by a laser method (for example, using LASER MICRON SIZER 7000S), and the Fischer method (for example, FISHER SUB-SIEVE). A size of 1.0 to 4.0 μm is preferable as measured by SIZER. Incidentally, in consideration of the effect as a flame retardant imparting agent, the average particle diameter of zinc carbonate is preferably in the range of 0.01 to 10 μm, the flame retardancy after curing of the composition and the roughness of the cured product surface In view of the feeling, it is preferable that the particle diameter is small. However, the adhesiveness tends to decrease as the particle size decreases.

  A preferred method for preparing (C) zinc carbonate used in the embodiment of the present invention is shown below. For example, zinc oxide is produced in the same way as the French method from zinc continuously distilled in a vertical round electric furnace similar to the St. Joseph method, which is one of the zinc electrorefining methods, and this is dissolved in sulfuric acid. Then, a trace amount of lead, iron, manganese and the like are removed with a permanganate solution to obtain a high purity zinc oxide sulfuric acid solution. This is reacted with a carbonate compound such as sodium carbonate. The carbonation rate and particle size are controlled by the temperature, pH and stirring speed of the reaction solution at this time. After the reaction, sufficient washing with water, filtration and drying can be carried out to obtain (C) zinc carbonate used in the embodiment of the present invention. As an example of the amount of impurities in the obtained zinc carbonate, K: 0.001 wt%, Na: 0.02 wt%, Cl: 0.001 wt%, Fe: 0.0003 wt%, Pb: 0.0001 wt%, Mn: 0.0002 wt% were detected. The Zn content was 51.71% by weight.

  Zinc carbonate used as the component (C) in the embodiment of the present invention contains almost no hydroxide, so that it has little deterioration in curability and is excellent in storage stability and used for electric / electronic parts. A composition having excellent adhesion to heat and flame retardant rubbers and heat resistant engineering plastics can be obtained. The amount of component (C) having such an effect is 1.0 to 100 parts by weight, more preferably 5 to 50 parts by weight, per 100 parts by weight of component (A). If it exceeds 100 parts by weight, the elasticity of the cured product is lowered and the adhesiveness is lowered, and if it is less than 1.0 part by weight, the flame retardancy becomes insufficient.

  Since the zinc carbonate (C) of the embodiment has a relatively large particle size, it tends to cause sedimentation / separation during storage and storage of the composition, and the original excellent flame retardancy may not be effectively exhibited. Therefore, in order to suppress such precipitation and separation of high-purity zinc carbonate and to suppress secondary aggregation, silicon-functional polydiorganosiloxane having hydrolyzable groups and / or hydrolyzable silane and its partial hydrolysis It is preferable to treat the surface of zinc carbonate, which is component (C), by mixing the products with a mixer or the like at a predetermined ratio.

  The silicon-functional polyorganosiloxane having hydrolyzable groups used for the surface treatment of zinc carbonate has polyorganosiloxane hydrolyzable groups only at both ends of the molecular chain as long as the desired properties of the rubber elastic body are not impaired. There can be any number in the molecule. Moreover, it is also possible and preferable to use the component (A) of the present invention. Moreover, in order to coat | cover the surface of zinc carbonate, hydrolysable silane and its partial hydrolyzate can be mix | blended.

  Examples of such silanes include tetramethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, tetrapropoxysilane, Alkoxy group-containing compounds such as tetraisopropoxysilane and partial hydrolysis condensates thereof; tetrakis (2-ethoxyethoxy) silane, methyltris (2-methoxyethoxy) silane, vinyl (2-ethoxyethoxy) silane, phenyltris ( Substituted alkoxy group-containing compounds such as 2-methoxyethoxy) silane and partial hydrolysis condensates thereof; methyltriisopropenoxysilane, vinyltriisopropenoxysilane, phenyltriiso Enoxy group-containing compounds such as lopenoxysilane, dimethyldiisopropenoxysilane, methylvinyldiisopropenoxysilane and their partial hydrolysis condensates; methyltris (methylethylketoxime) silane, vinyltris (methylethylketoxime) silane and their partial hydrolysis Ketoximato group-containing compounds such as degradation products; Acyloxy group-containing compounds such as methyltriacetoxysilane and partial hydrolysates thereof; 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethyl Isopropoxysilane, 3-aminopropyltriacetamidosilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrie Contains substituted or unsubstituted amino groups such as xylsilane, N-methyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N, N-dimethyl-3-aminopropyltrimethoxysilane Silane; 3-glycidoxytrimethoxysilane, 3-glycidoxymethyldimethoxysilane, epoxy group-containing silane such as 3,4-epoxycyclohexylethyltrimethoxysilane; 3-isocyanatopropyltrimethoxysilane, 3-isocyanate Isocyanato group-containing silane such as natopropylmethyldimethoxysilane; 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-methacryloxypropyl Mercapto group-containing silanes such as 3-mercaptopropyltrimethoxysilane; a (meth) acryloxy group-containing silane as chill dimethoxysilane a halogen atom-containing silanes such as and 3-chloropropyl trimethoxysilane and the like.

  Because it is inexpensive and easy to handle, tetramethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, tetrapropoxysilane, tetra Alkoxy group-containing compounds such as isopropoxysilane and partial hydrolysis condensates thereof are preferred. Further, trifunctional silanes such as methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, and phenyltriethoxysilane are more preferable.

  The amount of such silanes is preferably 0.1 to 5.0% by weight of the silicon-functional polyorganosiloxane having a hydrolyzable group provided simultaneously. In the surface treatment, it is preferable to heat to less than 130 ° C. during mixing with a mixer. When heating exceeds 130 ° C., zinc carbonate starts to decompose and begins to generate carbon dioxide gas. Since zinc carbonate exhibits weak basicity, the decomposition and crosslinking of hydrolyzable groups are promoted by heating, but dibutylamine is used as a catalyst so that crosslinking is promoted by the degree of heat generated when mixing from room temperature. A complex salt of dialkylamine (secondary amines) such as carboxylic acids such as formic acid and acetic acid is used in an amount of 0.0001 to 0.2% by weight of the silicon-functional polyorganosiloxane having a hydrolyzable group to be provided. More preferably. As the mixer, a wide variety of mixers such as a universal mixer, a roll machine, and a ball mill can be used. However, since they are economical and easy to handle, Use is preferred.

  In the embodiment of the present invention, in order to further improve the flame retardancy, (D1) a platinum-based compound or a complex compound thereof can be blended. Such (D1) platinum compounds or complex compounds thereof include chloroplatinic acid and solutions in which it is dissolved in alcohol or other solvents, and platinum compounds such as chloroplatinic acid containing ethylene, cyclooctadiene or vinyl groups. Examples include those obtained by reacting with siloxane and those obtained by coordination of a ligand (for example, a nitrile group-containing compound such as benzonitrile) with platinum. The blending amount of such (D1) platinum-based compound or its complex compound is preferably 1 to 2000 ppm as a platinum atom.

  Thus, when (D1) a platinum compound or its complex compound is blended, combustion due to resination of the cured product can be suppressed by the platinum atom in component (D1). However, in such a case, there may be inconveniences in actual use such as UL94 or the like when the test body is turned up during combustion or the test body becomes brittle and falls down. At this time, together with (D1) the platinum compound or its complex compound, (D2) a cyclic isocyanurate compound (for example, a silane-modified isocyanurate compound or a siloxane-modified isocyanurate compound) is added to the metal atom of (D1) component. The above-mentioned inconvenience can be eliminated by blending ˜60 times molar amount.

Examples of (D2) isocyanurate compounds include those having the structural formula shown below.

Here, R ⁵ , R ⁶ and R ⁷ are all unsubstituted or substituted monovalent hydrocarbon groups, or a general formula: —CH ₂ CH═CH ₂ or — (CH ₂ ) _r —SiR ⁸ (wherein , R ⁸ represents an alkyl group, an alkoxy group or — (O—SiR ⁹ R ¹⁰ ) _w R ¹¹ group, R ⁹ , R ¹⁰ and R ¹¹ represent an alkyl group or an alkoxy group, and r is an integer of 2 to 6. , W is an integer of 0 to 8) or — (CH ₂ ) _s COOH (wherein s is an integer of 1 to 8).

  Specific examples of such isocyanurate compounds include compounds represented by the following chemical formula and partial hydrolysates thereof, tris (2-carboxyethyl) isocyanurate and bis (2-carboxyethyl) isocyanurate, also called chic acid. Is exemplified. Among them, those having a hydrolyzable reactive group such as an alkoxysilyl group are preferable because they are incorporated into the curing reaction system.

  As described above, the amount of such an isocyanurate compound is 10 to 60 times, preferably 20 to 50 times the amount of the amide bond unit with respect to the metal atom of the component (D1). When the amount is less than 10 times mol, the deformation that the cured product is turned up due to generation of carbon dioxide gas during combustion is suppressed, and the effect of maintaining the shape of the cured product is small. When the amount exceeds 60 times mol, combustion is promoted. It is not preferable.

  Furthermore, since the cured product obtained from the composition of the embodiment of the present invention is generally hard and difficult to follow the movement of the seal part and the adhesion part, the member is sufficiently protected as a flame retardant by peeling at the adhesion interface. May cause problems such as being unable to do so. It can be improved by blending the (D2) isocyanurate compound described above, but by blending the (E) phosphorous acid compound, the hardness of the cured product can be suppressed without reducing the flame retardancy. . Examples of such phosphite compounds include triphenyl phosphite, tributyl phosphite, tri (2-ethylhexyl) phosphite, tridodecyl phosphite, and the like.

  Such (E) phosphorous acid compound is 0.005 to 1.0-fold mol amount, preferably 0.01 to 0.5-fold mol amount based on the metal atom of the curing catalyst which is component (B). Blended. If the amount is less than 0.005 moles, there is no effect. On the other hand, if it exceeds 1.0 moles, it not only causes inhibition of curing but also adversely affects adhesiveness. (B) In the case where the curing catalyst has a high catalytic activity such as an organotin compound, it is 0.05 to 1.0 times mol, preferably 0.1 to 0.7 times mol. In the case where the catalytic activity is smaller than that of the organotin compound such as zirconium, 0.005 to 0.5 times mol, preferably 0.01 to 0.2 times mol is used.

  Furthermore, in the embodiment of the present invention, it is preferable to blend (F) an organosilicon compound having a silazane bond as a storage stabilizer. Examples of such compounds include hexamethyldisilazane, disilazane such as 1,3-divinyltetramethyldisilazane, silazanes such as hexamethylcyclotrisilazane; N-trimethylsilyl-3-aminopropyltrimethoxysilane, N- Trimethylsilyl-3-aminopropyltriethoxysilane, N-methyldimethoxysilyl-3-aminopropyltrimethoxysilane, N-dimethylmethoxysilyl-3-aminopropyltrimethoxysilane, 1-sila-2-aza-1,1- Examples include silylaminoalkylsilanes such as dimethoxy-2-trimethylsilylcyclopentane and polycondensates thereof; compounds obtained by silylated aminoalkyl group-containing organopolysiloxanes with alkylsilanes, alkoxysilanes, and the like.

  The blending amount of the (F) organosilicon compound is 0.05 to 25 parts by weight, more preferably 0.5 to 15 parts by weight with respect to 100 parts by weight of the component (A). If it is less than 0.05 parts by weight, the curability is greatly deteriorated, and stable curing is not sufficient. Moreover, the blending of more than 25 parts by weight is not only meaningless but also disadvantageous economically, and adversely affects flame retardancy.

  In the embodiment of the present invention, it is required when a rubbery elastic body obtained by imparting appropriate fluidity to a composition before curing and used for curing, for example, as a sealing material, an adhesive, an in-situ molded gasket or the like. In order to impart a high mechanical strength, a filler usually used in a room temperature curable polyorganosiloxane composition can be blended.

  Examples of such fillers include inorganic fillers such as fumed silica, calcined silica, precipitated silica, and fumed titanium oxide, and their surfaces are hydrophobized with organochlorosilanes, polyorganosiloxanes, and hexamethyldisilazane. Reinforcing fillers such as things, diatomaceous earth, ground silica, aluminum silicate, zinc oxide, aluminum oxide, calcium carbonate, organic acid surface treatment calcium carbonate, magnesium carbonate, calcium silicate, talc, ferric oxide Examples of such non-reinforcing fillers are selected according to the physical properties required for the rubber-like elastic body after curing.

  When it is requested | required that it should have especially a low modulus as a sealing material for construction, it is preferable to use a non-reinforcing filler among these. If the amount of the reinforcing filler is too small, the effect of improving the mechanical properties hardly appears. Conversely, if the amount is too large, the modulus increases and the elongation at break decreases. Moreover, the addition amount of pulverized silica, aluminosilicate, zinc oxide, aluminum oxide, calcium carbonate, organic acid surface-treated calcium carbonate, magnesium carbonate, calcium silicate, talc, and ferric oxide, which are heavy fillers, is (A ) The range of 1 to 100 parts by weight is preferable with respect to 100 parts by weight of the component, and 5 to 50 parts by weight is more preferable.

  Furthermore, the composition of the embodiment includes a pigment, a thixotropic agent, a viscosity modifier for improving extrusion workability, an ultraviolet absorber, a fungicide, a heat resistance improver, and other flame retardants depending on the purpose. Various additives such as an agent may be added.

  The room temperature curable polyorganosiloxane composition of the embodiment of the present invention can be obtained by mixing all the above components and, if necessary, various additives in a state where moisture is blocked. The obtained composition can be used as a so-called one-packaging room temperature curable composition which is stored only in a sealed container and cured only by exposure to moisture in the air during use. In addition, the composition of the embodiment is prepared as a composition in which, for example, a crosslinking agent and a curing catalyst are separated, and is stored in two or three separate containers as appropriate, and these are mixed at the time of use. It can also be used as a room temperature curable composition.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to a following example. In the examples, “parts” means parts by weight, and all physical properties such as viscosity are values at 23 ° C. and relative humidity 50%.

Example 1
70 weight parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s has a weight loss rate of 0.07% when heated at 105 ° C. for 3 hours, and a weight loss rate of 34. 50% zinc carbonate (made by Toho Zinc Co., Ltd .; zinc carbonate-S) having a weight loss rate of 34% at 7%, an average particle size of 5.02 μm by LASER method, and 1.91 μm by FISHER method Was added and mixed uniformly, and then 30 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s was added and mixed uniformly.

  Next, 0.4 parts of a benzonitrile-chloroplatinic acid complex solution (platinum content 6.0%), methyltrimethoxysilane 3.0 parts, N-trimethylsilyl-3-aminopropyltrimethoxysilane 2.5 parts And 0.4 parts of dibutyltin dilaurate were added and mixed uniformly while blocking moisture to obtain a polyorganosiloxane composition.

Example 2
To 70 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s, 9.0 parts of zinc carbonate used in Example 1 and silicon dioxide powder (manufactured by Tatsumori Co., Ltd .; Crystallite) 5X) After adding 51 parts and mixing uniformly, 30 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s was added and mixed uniformly.

  Next, 0.4 parts of a benzonitrile-chloroplatinic acid complex solution (platinum content 6.0%), 5.0 parts of methyltrimethoxysilane, and 2.5 parts of diisopropoxytitanium bis (ethylacetylacetate) were added thereto. In addition, the mixture was uniformly mixed under moisture shielding to obtain a polyorganosiloxane composition.

Example 3
After adding 50 parts of zinc carbonate used in Example 1 to 70 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s and mixing them uniformly, a viscosity of 20,000 mPa · s is obtained. 30 parts of α, ω-bis (trimethoxysiloxy) polydimethylsiloxane was added and mixed uniformly.

  Subsequently, 0.4 parts of benzonitrile-chloroplatinic acid complex solution (platinum content 6.0%), 0.8 parts of cyclotri [N- (3-trimethoxypropyl) isocyanate] (30 parts per platinum atom) Polytriorganosilane, 3.0 parts of methyltrimethoxysilane, 2.5 parts of N-trimethylsilyl-3-aminopropyltrimethoxysilane, and 0.4 parts of dibutyltin dilaurate, respectively, and mixed uniformly under a moisture barrier. A siloxane composition was obtained.

Example 4
To 70 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s, 9.0 parts of zinc carbonate and 51 parts of silicon dioxide powder (crystallite 5X) used in Example 1 were added and uniform. Then, 30 parts of α, ω-bis (trimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s was added and mixed uniformly.

  Next, 0.4 parts of benzonitrile-chloroplatinic acid complex solution (platinum content 6.0%), 1.4 parts of cyclotri [N- (3-trimethoxypropyl) isocyanate] (45 parts per platinum atom). Double moles), 5.0 parts of methyltrimethoxysilane and 2.5 parts of diisopropoxytitanium bis (ethylacetylacetate) were added and mixed uniformly while blocking moisture to obtain a polyorganosiloxane composition.

Example 5
After adding 50 parts of zinc carbonate used in Example 1 to 70 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s and mixing uniformly, α having a viscosity of 20,000 mPa · s is used. , Ω-bis (trimethoxysiloxy) polydimethylsiloxane was added and mixed uniformly.

  Subsequently, 0.4 parts of benzonitrile-chloroplatinic acid complex solution (platinum content 6.0%), 0.8 parts of cyclotri [N- (3-trimethoxypropyl) isocyanate] (30 parts per platinum atom) Double moles), 3.0 parts of methyltrimethoxysilane, 2.5 parts of N-trimethylsilyl-3-aminopropyltrimethoxysilane, 0.4 parts of dibutyltin dilaurate and 0.1 part of triphenyl phosphite (on the tin atom) 0.5 moles relative to each other) was added and mixed uniformly while blocking moisture to obtain a polyorganosiloxane composition.

Example 6
To 70 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s, 9.0 parts of zinc carbonate and 51 parts of silicon dioxide powder (crystallite 5X) used in Example 1 were added and uniform. Then, 30 parts of α, ω-bis (trimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s was added and mixed uniformly.

  Next, 0.4 parts of benzonitrile-chloroplatinic acid complex solution (platinum content 6.0%), 5.0 parts of methyltrimethoxysilane, cyclotri [N- (3-trimethoxypropyl) isocyanate] 1. 4 parts (45 moles per platinum atom), 2.5 parts diisopropoxytitanium bis (ethylacetylacetate) and 0.03 part triphenyl phosphite (0.015 moles per titanium atom) Each was added and mixed uniformly while blocking moisture to obtain a polyorganosiloxane composition.

Example 7
After adding 50 parts of zinc carbonate used in Example 1 to 70 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s and mixing uniformly, α having a viscosity of 20,000 mPa · s is used. , Ω-bis (methyldimethoxysiloxy) polydimethylsiloxane was added and mixed uniformly.

  Next, 2.0 parts of 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane-chloroplatinic acid complex solution (platinum content 1.8%), cyclotri [N- (3-trimethoxypropyl) Isocyanate] 1.0 part (25 moles relative to platinum atoms), 3.0 parts of methyltrimethoxysilane, 2.5 parts of N-trimethylsilyl-3-aminopropyltrimethoxysilane, and 0.4 parts of dibutyltin dilaurate 0.1 parts of triphenyl phosphite (0.5 moles with respect to tin atoms) were added and mixed uniformly while blocking moisture to obtain a polyorganosiloxane composition.

Example 8
50 parts of zinc carbonate used in Example 1, 70 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s, 3.0 parts of vinyltrimethoxysilane, and diisobutylamine / formate 0 0.022 parts were mixed uniformly for 30 minutes with a universal mixer and the zinc carbonate particle surface was treated with polyorganosiloxane by passing the mixture through three rolls three times. Next, 70 parts of α, ω-bis (methyldimethoxysiloxy) polydimethylsiloxane having a viscosity of 20,000 mPa · s and 10 parts of silicon dioxide powder (crystallite 5X) were added and mixed uniformly.

  Next, 0.4 parts of triphenyl phosphite, 2.0 parts of 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane-chloroplatinic acid complex solution (platinum content 1.8%), cyclotri [ N- (3-trimethoxypropyl) isocyanate] 1.0 part (25-fold moles with respect to platinum atoms), 3-aminopropyltrimethoxysilane and hexamethyldisilazane in equimolar amounts using a catalytic amount of chlorosilane Add 3.0 parts of high molecular weight silazane bond-containing compound obtained by polycondensation, 0.4 part of dibutyltin dilaurate tin and 0.1 part of triphenyl phosphite (0.5 mol per tin atom). Then, the mixture was uniformly mixed under moisture shielding to obtain a polyorganosiloxane composition.

Example 9
Zinc carbonate used in Example 1 (weight loss rate when heated at 105 ° C. × 3 hours is 0.07%, weight loss rate at TG is 34.4%, weight loss rate due to generation of carbon dioxide gas is 33%, average particle size) Instead of 5.02 μm in diameter by LASER method and 1.91 μm in FISHER method), the weight loss rate of heating at 105 ° C. for 3 hours is 0.06%, the weight loss rate at TG is 34.4%, and carbon dioxide Zinc carbonate having a weight reduction rate due to generation of 33%, an average particle diameter of 0.51 μm by LASER method, and 0.18 μm by FISHER method was used. Other than that was carried out similarly to Example 1, and obtained the polyorganosiloxane composition.

Example 10
Instead of the zinc carbonate used in Example 2, the zinc carbonate used in Example 9 was used. Other than that was carried out similarly to Example 2, and obtained the polyorganosiloxane composition.

Example 11
A polyorganosiloxane composition was obtained in the same manner as in Example 1 except that the amount of zinc carbonate was 55 parts.

Example 12
A polyorganosiloxane composition was obtained in the same manner as in Example 2 except that 3 parts of zinc carbonate and 57 parts of silicon dioxide powder were used.

Comparative Example 1
Instead of zinc carbonate used in Example 1 (weight loss rate at heating at 105 ° C. for 3 hours is 0.07%, weight loss rate at TG is 34.7%, and weight loss rate due to carbon dioxide generation is 34%) In addition, basic zinc carbonate with a weight loss rate of 2.8% at 105 ° C for 3 hours, a weight loss rate of 27.4% with TG, and a weight loss rate of 14.8% due to the generation of carbon dioxide is blended did. Otherwise in the same manner as in Example 1, a polyorganosiloxane composition was prepared.

Comparative Example 2
A polyorganosiloxane composition was prepared in the same manner as in Example 2 using the basic zinc carbonate used in Comparative Example 1.

Comparative Example 3
Instead of the zinc carbonate used in Example 1, the weight loss rate after heating at 105 ° C. for 3 hours was 0.08%, the weight loss rate at TG was 31.4%, and the thermal weight loss rate due to the generation of carbon dioxide was 29. %, Zinc carbonate having an average particle diameter of 4.82 μm by LASER method and 1.73 μm by FISHER method was used. Other than that was carried out similarly to Example 1, and obtained the polyorganosiloxane composition.

Comparative Example 4
Instead of the zinc carbonate used in Example 1, the weight loss rate of heating at 105 ° C. for 3 hours was 0.04%, the thermal weight reduction rate at TG was 36.2%, and the thermal weight reduction rate due to carbon dioxide gas generation was Zinc carbonate having an average particle diameter of 29%, LASER method of 4.91 μm, and FISHER method of 1.82 μm was used. Other than that was carried out similarly to Example 1, and obtained the polyorganosiloxane composition.

  Next, for the polyorganosiloxane compositions prepared and sealed in Examples 1 to 12 and Comparative Examples 1 to 4, respectively, the touch drying time, physical properties, storage stability, The followability of the cured product with respect to adhesiveness and changes in members was measured and evaluated. Moreover, the flame retardance test was done and the flame retardance was measured and evaluated. Furthermore, about the polyorganosiloxane composition obtained in Examples 7-8, 11-12, and Comparative Example 3, respectively, the external appearance and specific gravity after standing for 6 months were measured, and sedimentation / separability was evaluated.

(A) Drying time of finger touch: After extruding the composition in an atmosphere of 23 ° C. and 50% RH, the time to contact the surface with a finger and confirm 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, left at 168 ° C. and 50% RH for 168 hours, cured by moisture in the air, and its physical properties were changed to JIS K 6301. Measured according to
(C) Storage stability: The composition was put in a container where moisture was cut off, heated at 70 ° C. for 5 days, and then the touch drying time was measured in an atmosphere of 23 ° C. and 50% RH. Further, the sheet was extruded in the form of a sheet having a thickness of 2 mm, allowed to stand at 23 ° C. and 50% RH for 168 hours, cured by moisture in the air, and its physical properties were measured according to JIS K 6301.
(D) Flame retardancy test:
(1); Evaluation was performed by a method based on UL94. At this time, the length of the test body after the combustion test was measured.
(2); 30 test specimens 1 (a = 3 mm, b = 3 mm, c = 2 mm) shown in FIG. 1 are prepared, and the state of the heat-resistant vinyl electric wire 2 inside the test specimen 1 is determined by a test method based on UL94. Observed. And the number of the test bodies 1 in which the state of the coating of the heat-resistant vinyl electric wire 2 changed, such as combustion or dissolution, was measured. In addition, the heat-resistant vinyl electric wire 2 is WLH-0.08 manufactured by Interwire Corporation having a maximum outer diameter of 1.00 mm, a conductor outer diameter of 0.4 mm, and a heat-resistant vinyl coating thickness of 0.2 mm.
(E) Flammability test: The oxygen index was measured according to JIS K7201-2.
(F) Adhesiveness: Adhesiveness to the adherend shown in Table 1 was qualitatively evaluated. The evaluation results are indicated by ◯ for good, Δ for good but insufficient, and x for non-adhesive. Also, the composition is applied onto each adherend, left standing at 23 ° C. and 50% RH for 168 hours and cured by moisture in the air, and then the cured product and the adherend are peeled in the direction of 180 °. The cohesive failure rate was measured.
(G) Followability: The composition was subjected to a 30% shear deformation repeated test according to the 9030G endurance test method described in JIS A5758, and the followability to changes in the cured material was evaluated.
(H) Sedimentation / separation: After leaving at room temperature for 6 months under moisture blocking, the appearance and specific gravity of the composition were measured to evaluate separation, sedimentation and aggregation. These measurement results are shown in Tables 1 and 2.

  According to the room temperature curable polyorganosiloxane composition of the present invention, the composition is stable under moisture-tight sealing conditions and particularly excellent in storage stability, and is cured at room temperature by contact with moisture in the air. A rubber-like elastic body having flame retardancy and adhesiveness is obtained. Therefore, the rubber-like elastic body obtained from the composition of the present invention is useful as a sealing material or as an adhesive or a coating agent.

In the Example of this invention, it is a figure which shows the structure of the test body used for a flame retardance test.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Test body, 2 ... Heat resistant vinyl electric wire.

Claims (7)

(A) (A1) silicon functional polydiorganosiloxane having an average number of hydrolyzable groups exceeding two as silicon functional groups in the molecule, and / or (A2) two or more silicon functional groups in the molecule. A room temperature curable polyorganosiloxane composition comprising a polyorganosiloxane comprising a silicon functional polydiorganosiloxane and a cross-linking agent comprising:
With respect to 100 parts by weight of the (A) polyorganosiloxane,
(B) 0.5 to 15 parts by weight of a curing catalyst;
(C) It contains 1.0 to 100 parts by weight of zinc carbonate having a weight reduction rate of 33 to 36% due to heating and a weight reduction rate of 30 to 35% due to generation of carbon dioxide during thermal decomposition. A room temperature curable polyorganosiloxane composition characterized by the above.   2. The room temperature-curable polyorganosiloxane composition according to claim 1, wherein an average particle diameter of zinc carbonate as the component (C) is 1.0 to 10 μm.   2. The carbon functional silane is contained as 0.05 to 25 parts by weight with respect to 100 parts by weight of the (A) polyorganosiloxane as at least a part of the crosslinking agent of the component (A2). 2. The room temperature curable polyorganosiloxane composition according to 2.   The flame retardant additive contains (D1) a platinum compound or a complex compound thereof, and (D2) isocyanurate compound is 10 to 60 times mol of the metal atom of the (D1) platinum compound or the complex compound. The room temperature-curable polyorganosiloxane composition according to any one of claims 1 to 3, which is contained in an amount.   The (E) phosphite is contained in an amount of 0.005 to 1.0 times the molar amount of the metal atom of the (B) curing catalyst, according to any one of claims 1 to 4. Room temperature curable polyorganosiloxane composition.   The (C) zinc carbonate is surface-treated with a silicon-functional polyorganosiloxane having a hydrolyzable group and / or a hydrolyzable silane or a partial hydrolyzate thereof. 6. The room temperature-curable polyorganosiloxane composition according to any one of 5 above.   7. A storage stabilizer containing 0.05 to 20 parts by weight of (F) an organosilicon compound having a silazane bond with respect to 100 parts by weight of the (A) polyorganosiloxane. 2. A room temperature curable polyorganosiloxane composition according to item 1.

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