JP4522816B2 - Adhesive polyorganosiloxane composition having flame retardancy - Google Patents

Description

  The present invention relates to an adhesive polyorganosiloxane composition that cures by an addition reaction, and particularly relates to a polyorganosiloxane composition that exhibits adhesiveness even when cured at room temperature, and the cured product has flame retardancy.

  As a curable polyorganosiloxane composition that exhibits fluidity in an uncured state and forms a rubber-like elastic body upon curing, an addition reaction curable composition and a condensation reaction curable composition are available depending on the curing mechanism. is there. Although the former hardens | cures even at room temperature depending on a composition, in order to express adhesiveness, it is necessary to heat to 70 degreeC or more. The latter cures at room temperature and develops adhesion, but it takes a long time to cure, has poor deep-curing properties, is difficult to bond a wide surface, and generates by-products during curing Therefore, there are problems such as shrinkage and lack of dimensional stability.

  Alkenyl group-containing polyorganosiloxane, polyorganohydrogensiloxane, and platinum-based metal compounds, which are the basic composition of addition reaction-curing polyorganosiloxane compositions, do not have an element that develops adhesiveness, thus providing adhesion. For this purpose, various additive components that are bonded to the network structure by copolymerization during crosslinking are blended.

  In Patent Document 1, the ratio of the number of hydrogen atoms bonded to silicon atoms to the number of alkenyl groups bonded to silicon atoms, typically vinyl groups (hereinafter referred to as Si—H / Vi ratio) is 0.5. In the above basic composition which is ˜4.0, a hydrogen atom bonded to a silicon atom and a following formula bonded to the silicon atom:

(Wherein, Q ¹ and Q ² each independently represents a linear or branched alkylene group, and R ³ represents an alkyl group having 1 to 4 carbon atoms)
It is disclosed that the composition exhibits an excellent adhesive property under curing conditions of 70 ° C. and 8 hours by blending an organosilicon compound having a side chain represented by the formula:

  In Patent Document 2, an epoxy compound and an aluminum chelate or an aluminum alcoholate compound are blended with a basic composition having a Si—H / Vi ratio of 0.5 to 5.0, and at 100 ° C. for 1 hour under curing conditions, It is disclosed that excellent adhesiveness is expressed.

  Patent Document 3 discloses that at least two of a (meth) acryloxyalkyl group-containing alkoxysilane, an epoxy group-containing alkoxysilane, and an isocyanurate compound have a basic composition having a Si-H / Vi ratio of 0.3 to 5.0. It is disclosed that, by blending, it is heated to 120 ° C. and exhibits excellent adhesion to plastic.

  Patent Document 4 discloses a hydrogen atom bonded to a silicon atom having an unsaturated group-containing β-diketone compound or β-diketone structure in a basic composition having a Si—H / Vi ratio of 0.5 to 4.0. It has been disclosed that, by blending an organosilicon compound having the above, excellent adhesion to metals and plastics can be achieved by heating in a short time at 100 to 120 ° C.

  In Patent Document 5, a linear polydiorganosiloxane and a resinous polyorganosiloxane are used in combination as the alkenyl group-containing polyorganosiloxane in the basic composition, and the Si—H / Vi ratio is 0.6 to 20.0. The composition containing an epoxy group-containing organosilicon compound and an inorganic filler is excellent in permeability to synthetic fibers for air bags and thin film coating properties, and is cured by heating at 180 ° C. and exhibits excellent adhesive strength. Is disclosed.

  However, in the conventional techniques including the inventions described in these documents, a polyorganosiloxane composition that forms a rubber-like elastic body by curing by an addition reaction is used to exhibit adhesion to various adherends at room temperature. It was impossible to do. Therefore, mounting and sealing of semiconductor devices, adhesion in the vicinity using heat-unstable materials such as semiconductors and general-purpose plastics, adhesion to general-purpose plastics on a wide surface, adhesion of parts that require deep curability Thus, there is a demand for an addition reaction type polyorganosiloxane composition that cannot be used in a condensation reaction type polyorganosiloxane composition and that can be used in applications where it is desired to develop adhesion without heating.

  On the other hand, the application of the addition reaction type polyorganosiloxane composition that exhibits adhesiveness upon curing includes mounting and sealing of semiconductor devices, and various electronic devices, especially aircraft, automobiles, railway vehicles, homes, etc. There are many things that require flame retardancy, such as electronic equipment used in For such applications, it is necessary to combine the above-mentioned adhesion at room temperature and flame retardancy.

  In the case of an addition reaction type polyorganosiloxane, the platinum compound used as a curing catalyst exhibits a flame retarding effect specific to the polyorganosiloxane, but depending on the application, it does not exhibit sufficient flame retardancy alone, Various flame retardants are often used in combination depending on the conditions of use. Such flame retardants include carbon black (Patent Document 6), a combination of pulverized quartz, carbon black and a metal carbonate such as zinc carbonate (Patent Document 7) and a combination of aluminum hydroxide, zinc carbonate and a triazole compound (Patent Document 7). Patent Document 8) is exemplified. However, these relate to rubbers or gels that do not have adhesiveness, and no addition reaction type polyorganosiloxane that exhibits both adhesiveness and flame retardancy at room temperature is known.

JP 54-48853 A JP-A-60-101146 Japanese Patent Laid-Open No. 03-37265 JP 2000-73041 A JP 05-214295 A Japanese Patent Laid-Open No. 07-113045 Japanese Patent Application Laid-Open No. 06-016937 JP 09-316335 A

  An object of the present invention is to provide an addition reaction type adhesive polyorganosiloxane composition that is fluid in an uncured state, cures at room temperature, and exhibits excellent adhesion and excellent flame retardancy. It is.

  As a result of repeated studies to solve the above problems, the present inventor, as a base polymer, contains an alkenyl group-containing linear polyorganosiloxane having a viscosity at 23 ° C. of 1.0 to 500 Pa · s, and an alkenyl group-containing polymer. Using a combination of branched polyorganosiloxanes, blending at least two organosilicon compounds having a Si-H / Vi ratio of 0.2 to 1.5 and having a carbon functional group and a silicon functional group Thus, the inventors have found that the problem can be solved, and have completed the present invention.

That is, the present invention
(A) A linear polyorganosiloxane containing 2 or more R ¹ (wherein R ¹ represents an alkenyl group) in the molecule and having a viscosity at 23 ° C. of 1.0 to 500 Pa · s. 100 parts by weight;
(B) SiO _4/2 unit and R ₃ SiO _1/2 unit, and optionally further R ₂ SiO unit (wherein R is R ¹ or R ² , wherein R ¹ is as described above) R ² represents an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated carbon-carbon bond)
5 to 100 parts by weight of a branched polyorganosiloxane in which at least 3 per molecule are R ¹ in R;
(C) Polyorganohydrogensiloxane having three or more hydrogen atoms bonded to silicon atoms in the molecule (A) and (B) The number of hydrogen atoms bonded to silicon atoms for one alkenyl group present in (B) is An amount of 0.2 to 1.5;
(D) Platinum group metal compound The quantity which contains a platinum group metal atom 0.1-1,000 weight ppm with respect to the total amount of (A) and (B);
(E) (E1) to (E3) below:
(E1) A hydrogen atom bonded to a silicon atom and the following formula (I) bonded to the silicon atom:

An organosilicon compound having a side chain represented by
(E2) an organosilicon compound having a Si (OR ³ ) _n group and an epoxy group-containing group,
(E3) Si (OR ³ ) silane compound having an _n group and an aliphatic unsaturated hydrocarbon group (wherein Q ¹ is a carbon chain having two or more carbon atoms between a silicon atom and an ester bond) Q ² represents a linear or branched alkylene group having 3 or more carbon atoms between an oxygen atom and a silicon atom in the side chain. R ³ represents an alkyl group having 1 to 4 carbon atoms or a 2-methoxyethyl group; n is an integer of 1 to 3)
At least two of the organosilicon compounds of 1.0 to 20 parts by weight; and (F) zinc carbonate, basic zinc carbonate, or a mixture thereof,
The present invention relates to an adhesive polyorganosiloxane composition not containing 10 parts by weight or more of an alkenyl group-containing linear polyorganosiloxane having a number average degree of polymerization of 250 or less.

  According to the present invention, it has fluidity in an uncured state, cures at room temperature, and exhibits excellent adhesion to various adherends during curing. Also, by UL94, an addition reaction type adhesive polyorganosiloxane composition that exhibits excellent flame retardancy of V-1 to V-0 at a thickness of 1 mm and V-0 at a thickness of 2 mm can be obtained. .

The linear polyorganosiloxane (A) used in the present invention is a component that serves as a base polymer in the adhesive polyorganosiloxane composition of the present invention. This component (A) has two or more alkenyl groups bonded to a silicon atom in one molecule, and can form a network structure by addition reaction with the Si—H bond of component (C). Any one can be used, but typically, the general formula (II):
(R ¹ ) _a (R ² ) _b SiO _{(4-ab) / 2} (II)
(Where
R ¹ represents an alkenyl group;
R ² represents an unsubstituted or substituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated carbon-carbon bond;
a is 1 or 2;
b is an integer of 0 to 2, provided that a + b is 2 or 3.
Is an alkenyl group-containing polyorganosiloxane having at least two alkenyl group-containing siloxane units in the molecule.

Examples of R ¹ include vinyl, allyl, 3-butenyl, 5-hexenyl, etc., which are easy to synthesize and do not impair the fluidity of the composition before curing and the heat resistance of the composition after curing. Therefore, a vinyl group is most preferable. a is preferably 1 because it is easy to synthesize.

Examples of the organic group bonded to the silicon atom of R ² and other siloxane units in the component (A) include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl; Cycloalkyl group; aryl group such as phenyl; aralkyl group such as 2-phenylethyl and 2-phenylpropyl; substituted carbonization such as chloromethyl, chlorophenyl, 2-cyanoethyl and 3,3,3-trifluoropropyl A hydrogen group is illustrated. Of these, a methyl group is most preferred because it is easy to synthesize and has an excellent balance of properties such as mechanical strength and fluidity before curing.

R ¹ may be present at either the end or in the middle of the molecular chain of the polyorganosiloxane (A), or may be present at both of them, in order to give excellent mechanical properties to the composition after curing. Is preferably present at least at both ends thereof. The siloxane skeleton of the component (A) is substantially linear, but some branching may exist.

  The viscosity of the component (A) is such that the uncured composition exhibits good fluidity, exhibits excellent workability during casting and potting, and the cured composition exhibits excellent mechanical strength. In order to show moderate elasticity and hardness, the viscosity at 23 ° C. is in the range of 1.0 to 500 Pa · s. This viscosity range is a typical (A) component, in the case of polymethylvinylsiloxane having both ends blocked with dimethylvinylsiloxane units and an intermediate unit consisting of dimethylsiloxy units, the number average degree of polymerization is 320-2, 000. The lower limit of the viscosity at 23 ° C. is preferably 3.0 Pa · s, more preferably 10.0 Pa · s. The upper limit is preferably 300 Pa · s, more preferably 200 Pa · s. In particular, the viscosity of the component (A) is preferably high in order to develop adhesiveness at room temperature, which is a feature of the present invention. The component (A) may be used alone or in combination of two or more. In the latter case, the viscosity means the viscosity of the mixed alkenyl group-containing polyorganosiloxane. . However, if the alkenyl group-containing linear polyorganosiloxane having a number average degree of polymerization of 250 or less is present in the composition of the present invention in an amount of 10 parts by weight or more with respect to 100 parts by weight of the component (A), the adhesiveness at room temperature. Is significantly inhibited. This degree of polymerization corresponds to about 0.5 Pa · s as a viscosity at 23 ° C. in the case of the representative component (A).

(B) component used for this invention becomes a base polymer of the composition of this invention with the above-mentioned (A) component, and is a component which gives the mechanical strength which was excellent in the composition especially after hardening. In particular, it is an indispensable component for obtaining a rubber-like elastic body having excellent mechanical strength when a Si-H / Vi region lower than that of a normal addition reaction type silicone rubber is selected. The component (B) is a branched polyorganosiloxane composed of SiO _4/2 units, R ₃ SiO _1/2 units, and optionally R ₂ SiO units (wherein R is as defined above). In particular, at least 3 Rs per molecule are R ¹ and the remainder is R ² so as to be crosslinking points in the curing reaction. To give the cured composition excellent mechanical strength, the ratio of R ₃ SiO _1/2 units to SiO _4/2 units is in the range of 1: 0.8 to 1: 3 as a molar ratio. A resinous solid or viscous semisolid at room temperature is preferred. In addition, although the silanol group exists in (B) component obtained by the method of cohydrolyzing and condensing organochlorosilanes, in this invention, silanol is processed by processing with alkaline substances, such as potassium hydroxide. It is preferable to use a group in which no silanol group is present by condensing groups.

Definition of R ¹ and R ^2, exemplary and preferred groups are respectively same as R ¹ and R ² of the above component (A). R ¹ may be present as R of the R ₃ SiO _1/2 unit, or may be present as R of the R ₂ SiO unit, but in order to obtain fast curing at room temperature, R ₃ SiO _1/2 It is preferably present in the unit, in other words, part or all of the R ₃ SiO _1/2 unit is preferably the R ¹ R ² ₂ SiO _1/2 unit.

  The amount of component (B) is in the range of 5 to 100 parts by weight with respect to 100 parts by weight of component (A), preferably 10 to 50 parts by weight. If it is less than 5 parts by weight, the effect of imparting mechanical strength is not sufficient, and if it exceeds 100 parts by weight, the apparent viscosity of the composition is remarkably increased and handling becomes difficult.

Polyorganohydrogensiloxane of component (C) used in the present invention, hydrosilyl group contained in the molecule, by addition reaction between R ¹ in component (A) and (B) in component ( It functions as a crosslinking agent for the component (A) and the component (B). In order to reticulate the cured product, it has at least three hydrogen atoms bonded to silicon atoms involved in the addition reaction. Such polyorganohydrogensiloxane is typically represented by the general formula (III):
(R ⁵ ) _c H _d SiO _{(4-cd) / 2} (III)
(Where
R ⁵ represents an unsubstituted or substituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated carbon-carbon bond;
c is an integer from 0 to 2;
d is 1 or 2, provided that c + d is an integer of 1 to 3)
At least 3 units in the molecule.

Examples of R ⁵ are the same as those of R ^{2 in the} component (A) described above, and among them, a methyl group is most preferable from the viewpoint of easy synthesis. Further, d is preferably 1 because synthesis is easy.

  The siloxane skeleton in the component (C) may be linear, branched or cyclic. Moreover, you may use these mixtures.

  The degree of polymerization of the component (C) is not particularly limited, but since polyorganohydrogensiloxane in which two or more hydrogen atoms are bonded to the same silicon atom is difficult to synthesize, it is preferably composed of three or more siloxane units. The number of siloxane units is more preferably 6 to 200, and particularly preferably 10 to 150, since it does not exhibit even when heated to the curing temperature and is excellent in fluidity and easily mixed with the component (A).

The amount of component (C) is such that sufficient adhesive strength is obtained, and the silicone rubber obtained by curing has excellent mechanical properties. Therefore, R ¹ group in component (A) and component (B) The amount of hydrogen atoms bonded to silicon atoms in the component (C) with respect to (Si-H / Vi) is 0.2 to 1.5, preferably 0.5 to 1.3. If Si-H / Vi is less than 0.2, a rubber-like elastic body having excellent mechanical strength cannot be obtained, and if it exceeds 1.5, sufficient adhesiveness at room temperature cannot be obtained.

  The platinum-based catalyst of the component (D) used in the present invention promotes the addition reaction between the alkenyl group in the component (A) and the component (B) and the hydrosilyl group in the component (C). It is a catalyst for introducing (E1) and / or (E3) into the siloxane network skeleton of the crosslinked polymer by addition reaction.

  As the platinum group metal compound, a compound of a platinum group metal atom such as platinum, rhodium, palladium is used, and chloroplatinic acid, a reaction product of chloroplatinic acid and an alcohol, a platinum-olefin complex, a platinum-vinylsiloxane complex, Examples include platinum compounds such as platinum-ketone complexes and platinum-phosphine complexes; rhodium compounds such as rhodium-phosphine complexes and rhodium-sulfide complexes; palladium compounds such as palladium-phosphine complexes.

  Of these, platinum-vinylsiloxane complexes are preferred because of their good catalytic activity, and they are cured in a short time at room temperature to exhibit adhesiveness. Therefore, platinum-1,1,3,3-tetramethyl-1 1,3-divinyldisiloxane complex is particularly preferred.

  Since the blending amount of the component (D) provides an excellent curing rate, when (E3) is used as the component (A) and the component (B) and the component (E) described later, the (E3) and Is usually from 0.1 to 1,000 ppm by weight, preferably from 0.5 to 200 ppm by weight, in terms of platinum group metal atoms.

  (E) component used for this invention is a component which provides adhesiveness to the composition of this invention, and combines with the polymerization degree and Si-H / Vi ratio of (A) component selectively used by this invention. Securing the expression of adhesiveness at room temperature. In addition, (E) component uses together at least 2 types among following (E1)-(E3) component, in order to provide the adhesiveness in the room temperature with respect to various adherends.

  (E1) is introduced into the crosslinked siloxane structure by the addition reaction with the component (A) and the component (B) during the addition reaction for curing the composition, and the side chain of the formula (I) is bonded. It is a component that contributes to the adhesiveness of the composition at room temperature as a part that exhibits the properties. Further, the alkoxy group present in the side chain of (E1) is converted into (E2) and / or (E3) as a siloxane skeleton by cohydrolysis / condensation reaction with the alkoxy group of (E2) and / or (E3). Also contribute to the introduction.

  The (E1) is a hydrogen atom bonded to a silicon atom and the following formula (I) bonded to the silicon atom:

(Wherein Q ¹ , Q ² and R ³ are as described above)
An organosilicon compound having a side chain represented by Examples of Q ¹ include an alkylene group such as ethylene, trimethylene, 2-methylethylene, and tetramethylene, and an ethylene group and a 2-methylethylene group are preferable because they are easy to synthesize and handle. Examples of Q ² include an alkylene group such as trimethylene, 2-methyltrimethylene, and tetramethylene, and a trimethylene group is preferable because synthesis and handling are easy. Examples of R ³ include alkyl groups such as methyl, ethyl, propyl, isopropyl, and butyl; and 2-methoxyethoxy groups, which give good adhesion and are liable to volatilize alcohol generated by hydrolysis. Group and ethyl group are preferred, and methyl group is particularly preferred.

  The hydrogen atom and the side chain, which are the characteristics of (E1), are preferably bonded to separate silicon atoms because they are easily synthesized. Therefore, the basic part of (E1) preferably forms a chain, branched or cyclic siloxane skeleton, and a cyclic siloxane skeleton is more preferable because a specific compound can be synthesized and purified with good control. The number of Si—H bonds contained in (E1) is an arbitrary number of 1 or more, and in the case of a cyclic siloxane compound, 2 or 3 is preferable.

  Examples of such (E1) include the following compounds, which may be used alone or in combination of two or more.

(E2) is an alkoxy group bonded to a silicon atom (hereinafter referred to as 2-methoxyethoxy group for OR ³ ) and an alkoxy group bonded to the silicon atom of (E1) and / or (E3). It is a component that is introduced into a crosslinked siloxane structure by a hydrolysis / condensation reaction and contributes to improving the adhesive property of the composition at room temperature, particularly to the plastic, as a portion where the epoxy group exhibits adhesiveness.

The (E2) is an organosilicon compound having a Si (OR ³ ) _n group and an epoxy group-containing group (wherein R ³ and n are as described above). Examples of R ³ are the same groups as in (E1), and a methyl group and an ethyl group are preferable, and a methyl group is particularly preferable because it provides good adhesion. As the epoxy group-containing group, an aliphatic epoxy group-containing group containing an ether oxygen atom, such as a 3-glycidoxypropyl group, is easy to synthesize, has no hydrolyzability, and exhibits excellent adhesiveness; An alicyclic epoxy group-containing group such as 2- (3,4-epoxycyclohexyl) ethyl group is preferred. The number of alkoxy groups bonded to the silicon atom is preferably 2 or more in the molecule. The OR ³ group and the epoxy group-containing group may be bonded to the same silicon atom or may be bonded to another silicon atom.

  Examples of such (E2) include 3-glycidoxypropyl groups such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropyl (methyl) dimethoxysilane. Containing alkoxysilanes; 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl (methyl) dimethoxy 2- (3,4-epoxycyclohexyl) ethyl group-containing alkoxysilanes such as silanes; partial hydrolysis condensates of these silanes with n being 2 or more; and some of the methyl groups of linear or cyclic methylsiloxanes , Trimethoxysiloxy group or 2- (trimethoxysilyl) ethyl If, such as carbon / silicon both functional siloxane which is replaced by the epoxy group-containing group mentioned above are illustrated, be used alone, no problem even in combination of two or more.

  (E3) is introduced into the crosslinked siloxane structure by a hydrolysis / condensation reaction between an alkoxy group bonded to a silicon atom and (E1) and / or (E2) an alkoxy group bonded to the silicon atom of the molecule, or The aliphatic unsaturated hydrocarbon group of (E3) is introduced into the crosslinked siloxane structure by addition reaction with the component (C) during the addition reaction for curing the composition, whereby the alkoxy group is converted into an alkoxy group. When used in combination with another (E3) alkoxy group and (E2), the other (E3) and / or (E2) is converted to a siloxane structure by cohydrolysis / condensation reaction with the (E2) alkoxy group. Introduce. And the remaining alkoxy group is a component which contributes to the improvement of the adhesiveness at room temperature of a composition, especially the adhesiveness with respect to a metal as a part which exhibits adhesiveness.

The (E3) is a silane compound having a Si (OR ³ ) _n group and an aliphatic unsaturated hydrocarbon group (wherein R ³ and n are as described above). Examples of R ³ are the same groups as in (E1), and a methyl group and an ethyl group are preferable, and a methyl group is particularly preferable because it provides good adhesion. n is preferably 2 or 3. In the case of an alkenyl group such as vinyl, allyl, and 3-butenyl, the aliphatic unsaturated hydrocarbon group may be directly bonded to the silicon atom, such as 3-acryloxypropyl and 3-methacryloxypropyl, The unsaturated acyloxy group may be bonded to the silicon atom via 3 or more carbon atoms. The unsaturated hydrocarbon group-containing group is preferably a vinyl group or a methacryloxypropyl group because it can be easily synthesized and handled.

  Examples of such (E3) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, methylvinyldimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, and methylallyldimethoxysilane. Alkenylalkoxysilanes; 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-acryloxypropyl (methyl) dimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxy (Meth) acryloxypropylalkoxysilanes such as silane and 3-methacryloxypropyl (methyl) dimethoxysilane are exemplified, and one kind may be used alone, or two or more kinds may be used in combination. Permissible not.

  (E) component contains the above-mentioned (E1) and (E2); (E1) and (E3); (E2) and (E3); or (E1), (E2) and (E3), Along with other components, the composition functions to exhibit adhesiveness to a wide range of adherends at room temperature. The component (E) preferably contains a combination of (E1) and (E2) and / or (E3). (E) The compounding quantity of a component is the range of 1.0-20 weight part with respect to 100 weight part of (A) component as a total amount of this (E) component, and 3.0-15 weight part is preferable. . When the component (E) is less than 1 part by weight, the adhesiveness at room temperature is not sufficient, and when it exceeds 20 parts by weight, the density of crosslinking due to the addition reaction between the components (A), (B) and (C) is low. Not only does the mechanical strength of the adhesive layer obtained by curing decrease, but also when exposed to a high temperature of 200 ° C. or higher, crosslinking by the condensation reaction of the alkoxy groups remaining in the adhesive layer proceeds, and the hard layer becomes hard. Increases, elongation decreases, and the adhesive layer is destroyed. In addition, when (E) component is said 2 types of mixture, in order to obtain favorable adhesiveness, in (E) component, one is the range of 0.05-20 times of the other by weight ratio. Is preferred. Moreover, when (E) component is a mixture of (E1), (E2), and (E3), it is preferable that each is mix | blended 5 weight% or more of (E) component.

The component (F) used in the present invention is a flame retardant that imparts flame retardancy to the cured composition. (D) The catalytic ability of the component is not hindered, and carbon dioxide is generated by heat to produce an oxygen blocking effect, so that sufficient flame retardancy is imparted to the cured composition without blending in excessive amounts. Therefore, the uncured composition maintains sufficient fluidity, and the system exhibits sufficient adhesiveness when cured at around room temperature. As the component (F), zinc carbonate, that is, ZnCO ₃ , basic zinc carbonate, that is, 2ZnCO ₃ .3Zn (OH) ₂ .H ₂ O, and a mixture thereof (hereinafter collectively referred to as zinc carbonates) are used. As such zinc carbonates, the hardened composition exhibits better flame retardancy with a small amount of blending, and does not interfere with its function by reacting with the component (E). The main component is zinc, and high purity zinc carbonate having a purity of 95% by weight or more, a thermal weight reduction rate of 33 to 36% in thermal analysis, and a carbon dioxide gas generation amount of 30% by weight or more is particularly preferable.

  (F) The compounding quantity of a component is 3.0-50 weight part with respect to 100 weight part of (A) component, and 6.0-25 weight part is preferable. When the component (F) is less than 3.0 parts by weight, the cured composition cannot be provided with sufficient flame retardancy, and when it exceeds 50 parts by weight, sufficient adhesiveness is obtained at the time of curing near room temperature. It cannot be expressed.

In the present invention, a tetraalkoxysilane represented by Si (OR ⁴ ) ₄ (wherein R ⁴ represents an alkyl group having 1 to 3 carbon atoms), or a partially hydrolyzed condensate thereof, as the component (G). This may further improve the adhesion to metal at room temperature.

Examples of R ⁴ include linear or branched alkyl groups such as methyl, ethyl, propyl, and isopropyl, which are easily available, easy to handle, and have a remarkable effect of improving adhesiveness. Groups are preferred.

  Since the silicone rubber obtained by curing imparts excellent adhesion to metal at room temperature, the amount of component (G) is 0.1 to 10 parts by weight per 100 parts by weight of component (A). Is preferably 0.5 to 5 parts by weight.

  Other adhesiveness-imparting agents may be used in combination with the composition of the present invention as long as the catalytic ability of the component (D) is not impaired. Such adhesion promoters include aluminum alkoxides such as aluminum triethoxide, aluminum tripropoxide, aluminum tributoxide; titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, titanium. Examples include titanium alkoxides such as tetraisobutoxide and titanium tetraisopropenyl oxide; zirconium alkoxides such as zirconium tetraisopropoxide and zirconium tetrabutoxide, and the like. By the combined use of such metal alkoxides, the adhesion strength can be further increased. The compounding amount of the metal alkoxide is preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the component (A).

  Other flame retardants may be used in combination with the composition of the present invention as long as the catalytic ability of the component (D) is not impaired. Examples of such a flame retardant include triazole compounds such as benzotriazole; aluminum hydroxide and the like. Of the materials listed as fillers described later, carbon black and pulverized quartz also have the property of imparting flame retardancy, so they may be used in combination.

  Examples of the adhesion-imparting agent that may be blended in the composition of the present invention include organic compounds containing a polar group in the molecule, such as diallyl maleate. This type of adhesion-imparting agent suppresses the curing reaction rate of the composition and contributes to improvement in handling workability and the balance between the expression of adhesiveness and the curing rate. As the curing inhibitor, known compounds including unsaturation such as acetylene alcohols and derivatives thereof can be used in addition to the above.

  In order to give the composition of the present invention appropriate fluidity at the stage before curing, and to give the rubber-like elastic body obtained by curing high mechanical strength required according to its use, it is filled with an inorganic material. It is preferable to add an agent. Such inorganic fillers include fumed silica, calcined silica, silica aerogel, precipitated silica, fumed titanium oxide, and reinforcements such as those hydrophobized with polyorganosiloxanes, hexamethyldisilazane, etc. Fillers; and non-reinforcing like diatomaceous earth, ground silica, aluminum oxide, zinc oxide, aluminosilicate, calcium carbonate, organic acid surface treated calcium carbonate, magnesium carbonate, calcium silicate, talc, ferric oxide Fillers are exemplified, and are selected according to extrusion workability and physical properties required for a rubber-like elastic body obtained by curing. Further, a conductive filler such as carbon black may be blended depending on the purpose. The addition amount of these fillers is not limited as long as the purpose of use of the composition is not impaired.

  Furthermore, the composition of the present invention includes various pigments, thixotropy imparting agents, viscosity modifiers for improving extrusion workability, UV inhibitors, fungicides, heat resistance improvers, etc., depending on the purpose. Additives may be added. Depending on the application, the composition of the present invention may be dissolved or dispersed in an organic solvent such as toluene or xylene.

  The composition of the present invention can be prepared by uniformly kneading the components (A) to (F) and other components to be blended as necessary with a mixing means such as a universal kneader or a kneader. . In order to facilitate handling, a solid or semi-solid resinous material as component (B) may be blended as a hydrocarbon solution such as toluene or xylene. In that case, a part or all of the component (A) is mixed with the above solution containing the component (B), and then the solvent is distilled off by heating under reduced pressure to obtain a solution of the component (A) and the component (B). It can be used for the preparation of the composition. In addition, in order to stably store for a long period of time, the component (D) is divided into two containers and stored so that the component (D) becomes a separate container with respect to the component (C) and the component (E1). They may be mixed immediately before use and defoamed under reduced pressure for use.

  The polyorganosiloxane composition of the present invention is adhered to an object to be bonded by a method such as injection, dripping, casting, casting, extrusion from a container, or integral molding by transfer molding or injection molding. The silicone rubber can be obtained by allowing it to stand at room temperature and curing it, and at the same time, it can be adhered to the object to be bonded. Usually, the surface is dry to the touch when left at room temperature for 18 hours. The standing time for developing adhesiveness is usually 18 hours or longer, preferably 24 hours or longer. The touch drying time and the adhesive development time can be arbitrarily set by changing the type and amount ratio of the component (D) and the reaction inhibitor. If necessary, curing and adhesion can be performed by heating at a relatively low temperature, for example, 80 ° C. for 30 minutes or 100 ° C. for 10 minutes.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In these examples, parts indicate parts by weight, and the viscosity indicates the viscosity at 23 ° C. The present invention is not limited by these examples.

The following polysiloxanes were used in Examples and Comparative Examples. Hereinafter, siloxane units are indicated by the following symbols.
M Unit: (CH ₃ ) ₃ SiO _1/2 −
M ^v unit: (CH ₃ ) ₂ (CH ₂ ═CH) SiO _1/2 −
D Unit: - (CH _{3) 2} SiO-
D ^H units: - (CH ₃₎ HSiO-
D ^v _{Unit: - (CH 3) (CH} 2 = CH) SiO-
Q Unit: SiO _4/2 (tetrafunctional)
A-1: Linear polymethylvinylsiloxane having both ends blocked with ^Mv units, an intermediate unit consisting of D units, and a viscosity at 23 ° C. of 100 Pa · s;
A-2: linear polymethylvinylsiloxane having both ends blocked with ^Mv units, intermediate units consisting of D units, and a viscosity at 23 ° C. of 10 Pa · s;
A-3: both ends are blocked with M ^v basis, will intermediate units from D units, linear polymethylvinylsiloxane having a viscosity at 23 ° C. is at 3.0 Pa · s;
A-4: both terminals blocked with M ^v basis, will intermediate units from D units, linear polymethylvinylsiloxane having a viscosity at 23 ° C. is at 0.35 Pa · s;
B-1: Branched polymethylvinylsiloxane consisting of M units, M ^v units and Q units and having a molar unit ratio of M ₅ M ^v Q ₈ ;
C-1: Linear polymethylhydrogen having both ends blocked with M units, an intermediate unit consisting of 50 mol% ^DH units and the remaining D units, and a viscosity at 23 ° C. of 0.2 Pa · s Siloxane.

In the examples and comparative examples, the following platinum-vinylsiloxane complex was used as a catalyst.
D-1: a complex obtained by heating chloroplatinic acid with a siloxane dimer represented by M ^v M ^v and having a platinum content of 2% by weight;
D-2: A complex obtained by heating chloroplatinic acid with a cyclic siloxane represented by D ^v ₄ and having a platinum content of 2% by weight.

In the examples and comparative examples, the following organosilicon compounds were used as the component (E).
E-1: Formula:

An isomer mixture of cyclic siloxanes represented by:
E-2: 3-glycidoxypropyltrimethoxysilane;
E-3: Vinyltriethoxysilane.

In Examples and Comparative Examples, the following zinc carbonates were used as the component (F).
F-1: 97 wt% purity by XFR, 34% carbon dioxide gas generation amount determined by GC-MS quantitative method, thermal analysis of measurement temperature range 25-500 ° C. (Seiko Electronics Co., Ltd., TG / DTA220) Zinc carbonate with a thermal weight loss rate of 34.7%.

The following pulverized silica was used in Examples and Comparative Examples.
S-1: pulverized quartz having an average particle diameter of 1.2 μm

Examples 1-6, Comparative Examples 1-4
As shown in Table 1, a polyorganosiloxane composition was prepared by the following method using the raw materials. A-1 and a B-1 toluene solution having a concentration of 50% by weight prepared in advance are placed in a container equipped with a stirrer, a heating device, and a decompression device, and mixed uniformly to 150 ° C. and 0.13 kPa. Toluene was distilled off with {1 Torr} to prepare a polysiloxane solution. Transfer this to a universal kneader, add F-1 and optionally S-1, knead under reduced pressure at 100 ° C for 3 hours, cool to 40 ° C or lower, and mix diallyl maleate and D-1 did. Next, defoaming is performed by adding a mixture of A-3, C-1, E-1, E-2 and E-3 prepared in advance and quickly kneading under reduced pressure for 10 minutes. A polyorganosiloxane composition was prepared.

Examples 7-10, Comparative Examples 5-8
In the same manner as in Example 1, Example 7 in which tetraethoxysilane was blended instead of diallyl maleate in the composition of Example 2, Example 8 in which tetraethoxysilane was blended instead of E-3, and C Each composition of Comparative Example 5 containing -1 in excess was prepared. In addition, A-2 was used in place of A-3, and the composition ratio of each component was changed in Example 9, and (A) all components were used as A-2. Example 10 was prepared, with 65 parts devoted to preparing a solution with B-1 and the remainder devoted to preparing a solution with C-1 and an adhesion-imparting component. Furthermore, Comparative Example 6 using each of the compositions of Example 9 using A-4 having a low molecular weight instead of A-2, Comparative Example 7 using only E-1 as the component (E), and (E) Each composition of Comparative Example 8 using only E-3 as a component was prepared.

Evaluation Method and Results Evaluation of hardness, flame retardancy and adhesiveness of the compositions of Examples 1 to 10 and Comparative Examples 1 to 8 was performed using the following methods.
(1) Hardness Each composition was cast from a coker and allowed to stand at room temperature for 24 hours to prepare a sheet having a thickness of 2 mm. Three sheets were stacked and the hardness was measured using a type E durometer according to JIS K6253. However, in Example 4, the hardness after being left for 72 hours was measured.
(2) Flame retardance 1 mm and 2 mm thick sheets were produced by casting similar to the above, and allowed to stand at room temperature for 24 hours, and then flame retardancy was evaluated by a UL94 20 mm vertical combustion test.
(3) Adhesiveness Each coker was filled with a composition. The composition was extruded on a test piece (80 × 25 × 2 mm) of various materials shown in Table 2 from a coker so as to form a bead having a diameter of 10 mm and a length of 60 mm, and left at room temperature for 24 hours or 72 hours. Then, it was cured and bonded to obtain a rubber-like cured product. Thereafter, a 20 mm incision was made with a knife at the end of the interface between the cured product and the specimen, and the cured product was pulled in the direction of 90 ° upward until breaking, and the adhesiveness was evaluated according to the breaking condition.
○: Excellent adhesiveness (the cured product is broken, and the cured product adheres to 100% of the adhesion surface with the specimen)
Δ: Good adhesion (cured product partially adheres to the adhesive surface with the specimen, and part of it peels off)
×: No adhesion (the cured product peels off from the specimen, and the cured product does not adhere to the adhesive surface)

  The evaluation results are shown in Table 3 and Table 4.

  As is apparent from Tables 3 and 4, the polyorganosiloxane composition of the present invention is cured at room temperature and exhibits excellent adhesion, and the silicone rubber obtained by curing has a V thickness of 1 mm according to UL94. Excellent flame retardancy of V-0 was exhibited at -1 to V-0 and a thickness of 2 mm. On the other hand, the composition of Comparative Example 1 in which F-1 was not blended and the composition of Comparative Example 2 with a small amount of F-1 were both excellent in adhesion to various adherends, but were obtained. Silicone rubber did not exhibit flame retardancy at a thickness of 1 mm, and did not exhibit sufficient flame retardance even at a thickness of 2 mm. In addition, the composition of Comparative Example 3 having a large amount of F-1 provides an excellent flame-retardant silicone rubber, but does not exhibit adhesiveness to many metals and plastics, and instead of F-1. In the composition of Comparative Example 4 in which a large amount of pulverized silica was blended, a silicone rubber exhibiting some flame retardancy was obtained, but the adhesion was even worse.

  The composition of Comparative Example 5 has a Si—H / Vi ratio of 2.5, which is a general range for ordinary addition-reactive silicone rubber, and has a Si—H bond excess region for the present invention. In spite of blending various adhesion-imparting agents, the adherend other than glass did not exhibit adhesion at room temperature. The composition of Comparative Example 6 uses a vinyl group-containing linear polyorganosiloxane having a low degree of polymerization. It did not show any adhesiveness. Further, the composition of Comparative Example 7 uses only E-1 as the component (E), and the composition of Comparative Example 8 similarly uses only E-3. Although the composition of Comparative Example 7 exhibited excellent adhesion to glass, the adhesion to other adherends was poor, and the composition of Comparative Example 8 did not exhibit sufficient adhesion.

  The polyorganosiloxane composition of the present invention provides a silicone rubber that exhibits excellent adhesion when cured at room temperature and also exhibits excellent flame retardancy of UL94V-0 at a thickness of 2 mm. Therefore, the polyorganosiloxane composition of the present invention is a semiconductor device mounting and sealing, adhesion in the vicinity using a thermally unstable material such as semiconductors and general-purpose plastics, adhesion in a wide area to general-purpose plastics, Applications that require both flame retardancy and adhesiveness in applications where heating cannot be performed and condensation reaction type adhesive polyorganosiloxane compositions cannot be used, such as adhesion of sites that require deep curing It is very useful industrially.

Claims (7)

(A) A linear polyorganosiloxane containing 2 or more R ¹ (wherein R ¹ represents an alkenyl group) in the molecule and having a viscosity at 23 ° C. of 1.0 to 500 Pa · s. 100 parts by weight;
(B) SiO _4/2 unit and R ₃ SiO _1/2 unit, and optionally further R ₂ SiO unit (wherein R is R ¹ or R ² , wherein R ¹ is as described above) R ² represents an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated carbon-carbon bond)
5 to 100 parts by weight of a branched polyorganosiloxane in which at least 3 per molecule are R ¹ in R;
(C) Polyorganohydrogensiloxane having three or more hydrogen atoms bonded to silicon atoms in the molecule (A) and (B) The number of hydrogen atoms bonded to silicon atoms for one alkenyl group present in (B) is An amount of 0.2 to 1.5;
(D) Platinum group metal compound An amount containing 0.1 to 1,000 ppm by weight of a platinum-based metal atom with respect to the total amount of (A) and (B);
(E) (E1) to (E3) below:
(E1) A hydrogen atom bonded to a silicon atom and the following formula (I) bonded to the silicon atom:

An organosilicon compound having a side chain represented by
(E2) an organosilicon compound having a Si (OR ³ ) _n group and an epoxy group-containing group,
(E3) Si (OR ³ ) silane compound having an _n group and an aliphatic unsaturated hydrocarbon group (wherein Q ¹ is a carbon chain having two or more carbon atoms between a silicon atom and an ester bond) Q ² represents a linear or branched alkylene group having 3 or more carbon atoms between an oxygen atom and a silicon atom in the side chain. R ³ represents an alkyl group having 1 to 4 carbon atoms or a 2-methoxyethyl group; n is an integer of 1 to 3)
At least two of the organosilicon compounds of 1.0 to 20 parts by weight; and (F) zinc carbonate, basic zinc carbonate, or a mixture thereof,
An adhesive polyorganosiloxane composition containing no more than 10 parts by weight of an alkenyl group-containing linear polyorganosiloxane having a number average degree of polymerization of 250 or less.   The adhesive polyorganosiloxane composition according to claim 1, wherein the viscosity of (A) at 23 ° C is 3.0 to 300 Pa · s. The adhesive polyorganosiloxane composition according to claim 1 or 2, wherein R ^{1 in} (A) and (B) is a vinyl group.   The adhesive polyorganosiloxane composition according to any one of claims 1 to 3, wherein (D) is a platinum-vinylsiloxane complex.   The adhesive polyorganosiloxane composition according to claim 4, wherein (D) is a platinum-1,1,3,3-tetramethyl-1,3-divinyldisiloxane complex. (F) is a mixture of zinc carbonate and basic zinc carbonate, wherein the purity of zinc carbonate is 95% by weight or more, the weight reduction rate in thermal analysis is 33 to 36%, and the amount of carbon dioxide generation is 30% by weight or more. there, adhesive polyorganosiloxane composition of any one of claims 1 to 5. Furthermore, tetraalkoxysilane represented by (G) Si (OR ⁴ ) ₄ (wherein R ⁴ represents an alkyl group having 1 to 3 carbon atoms), or a partial hydrolysis condensate thereof 0.1 to 10 weights The adhesive polyorganosiloxane composition of any one of Claims 1-6 containing a part.