JP4678171B2 - Primer composition - Google Patents

Description

  The present invention is capable of bonding a heat-curable silicone rubber composition having excellent adhesiveness, particularly a silicone rubber obtained by curing a heat-curable silicone rubber composition having high thermal conductivity, to various adherends. It is related with the primer composition which can be performed.

Conventionally, in order to adhere silicone rubber to various adherends, a method of applying various primer compositions is generally employed. As this primer composition, for example, Japanese Patent Publication No. 61-2107 (Patent Document 1) discloses a primer composition comprising an organosilicon compound having an alkoxy group, an organotitanium compound, and an organosilicon compound having a SiH group, JP-A-6-25615 (Patent Document 2) proposes a primer composition comprising an organosilicon compound having a group represented by the general formula —CR ² R ³ (CH ₂ ) _n COOR ¹ .

  On the other hand, in recent years, with the increase in the speed of dry copying machines (PPCs) and laser beam printers (LBPs), the demand for high thermal conductive silicone rubber has increased. Also, silicone rubber with high thermal conductivity is used for automobile parts and computer parts, and high thermal conductivity of silicone rubber is a necessary condition. However, the high thermal conductivity silicone rubber often does not adhere to various adherends in the conventional primer composition as described above. For this reason, the above high thermal conductivity silicone rubber is not attached to the adherend. Development of a primer composition that can be bonded has been desired.

Japanese Examined Patent Publication No. 61-2107 JP-A-6-25615

  The present invention has been made in view of the above circumstances, and is a primer composition capable of adhering a cured product (silicone rubber) of a heat-curable silicone rubber composition having excellent adhesiveness and high thermal conductivity to various adherends. The purpose is to provide.

  The present inventors have found that a silicone rubber obtained by curing a heat-curable silicone rubber composition having high heat conductivity contains a large amount of heat-conductive filler, and therefore usually has a low crosslink density, which is sufficient with conventional primer compositions. It was thought that the reason why the interaction between the primer and the silicone rubber was caused by the fact that this interaction did not work. Therefore, in order to achieve the above object, as a result of various studies on compounds capable of enhancing the interaction with silicone rubber, organoalkoxysilane or siloxane of the following average composition formula (1), alkoxy of the following average composition formula (2) By compounding a silyl group-containing organohydrogensilane or siloxane and a dialkoxytitanium polymer, it gives a moderate stress relaxation action and is extremely effective in improving the adhesion of the primer composition. It has been found that the adhesiveness between the high thermal conductive silicone rubber and the primer can be dramatically improved, an appropriate stress relaxation effect can be obtained, and the adhesiveness with the high thermal conductive silicone rubber is excellent.

  In particular, the alkoxysilyl group-containing organohydrogensiloxane of the following average composition formula (2) has a SiH group at the end of the molecular chain represented by the following general formula (3) or (4) and has an alkoxysilyl group in the molecule. In the primer composition, the SiH group is effectively incorporated into the matrix of the primer to enhance the interaction between the high thermal conductivity silicone rubber and the primer composition, and to provide a stress relaxation action. It is extremely effective in improving adhesiveness, and can significantly improve the adhesiveness between the high thermal conductivity silicone rubber and the primer, and provides an appropriate stress relaxation effect. It has been found that the adhesiveness is particularly excellent, and has led to the present invention.

That is, the present invention is a primer composition for adhering silicone rubber to metal or plastic,
( I) The following average composition formula (1)
R ¹ _a R ² _b (OR ³ ) _c SiO _{(4-abc) / 2} (1)
(Wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group, R ² is a monovalent organic group having a functional group, R ³ is an unsubstituted or alkoxy-substituted alkyl group, and a, b, and c are (0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 0 <c ≦ 4, and 0 <a + b + c ≦ 4)
100 parts by mass (II) The following average composition formula (2)
H _d R ⁴ _e (XSiR ⁵ _g (OR ⁶ ) _h ) _f SiO _{(4-def) / 2} (2)
(Wherein R ⁴ and R ⁵ are each an unsubstituted or substituted monovalent hydrocarbon group, R ⁶ is an unsubstituted or alkoxy-substituted alkyl group, X is an unsubstituted or substituted divalent organic group or an oxygen atom. , D, e, and f are numbers satisfying 0 <d ≦ 2, 0 ≦ e ≦ 3, 0 <f ≦ 3, and 0 <d + e + f ≦ 4, g is 0, 1 or 2, h is 1, 2 or 3 and g + h = 3.)
A primer composition for silicone rubber, comprising 1 to 500 parts by mass of an alkoxysilyl group-containing organohydrogensilane or siloxane represented by formula (III) dialkoxytitanium polymer 0.1 to 500 parts by mass provide.
Also provided is a method for adhering silicone rubber, characterized in that the primer composition is applied to the surface of a metal or plastic adherend, and silicone rubber is adhered thereon. In this case, as a silicone rubber, a cured product of a highly thermally conductive thermosetting silicone rubber composition containing 100 to 1,000 parts by mass of a thermally conductive filler with respect to 100 parts by mass of the composition excluding the thermally conductive filler. Can be effectively bonded.

（式中、Ｒ⁷、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹はそれぞれ非置換又は置換の１価炭化水素基、Ｙは非置換又は置換の２価有機基、Ｒ¹²は非置換又はアルコキシ置換のアルキル基であり、ｋ、ｍ、ｍ’、ｒはそれぞれ０＜ｋ≦２０、０≦ｍ≦２０、１≦ｍ’≦２０、１≦ｒ≦２０を満たす整数であり、ｐは０、１又は２、ｑは１、２又は３であり、かつｐ＋ｑ＝３である。） In this case, as the (II) component alkoxysilyl group-containing organohydrogensiloxane, those represented by the following general formula (3) or (4) are suitable.

Wherein R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each an unsubstituted or substituted monovalent hydrocarbon group, Y is an unsubstituted or substituted divalent organic group, and R ¹² is unsubstituted or alkoxy. A substituted alkyl group, k, m, m ′, r are integers satisfying 0 <k ≦ 20, 0 ≦ m ≦ 20, 1 ≦ m ′ ≦ 20, 1 ≦ r ≦ 20, and p is 0 1 or 2, q is 1, 2 or 3, and p + q = 3.)

  The primer composition of the present invention has excellent adhesive properties, and heat-curable silicone rubber compositions, particularly silicone rubbers obtained by curing heat-curable silicone rubber compositions with high thermal conductivity, are firmly attached to various adherends. Can be glued.

  Among the various adherends, the primer composition of the present invention adheres silicone rubber, particularly high thermal conductivity silicone rubber to metals such as iron, aluminum, stainless steel, nickel, zinc, tin-plated steel sheets, and various plastics. It can be suitably used for bonding to a body, and can be used particularly effectively as a primer for bonding a metal or other various base materials used for, for example, a roll portion of a copying machine or parts around an engine to silicone rubber. It is also highly effective for fluororesins.

Hereinafter, the present invention will be described in more detail.
The primer composition of the present invention comprises:
(I) 100 parts by mass of an organoalkoxysilane or siloxane represented by the following average composition formula (1), and (II) 1 to 500 parts by mass of an alkoxysilyl group-containing organohydrogensiloxane represented by the following average composition formula (2): , (III) dialkoxytitanium polymer 0.1 to 500 parts by mass.

In the primer composition of the present invention, the organoalkoxysilane or siloxane as the component (I) is represented by the following average composition formula (1).
R ¹ _a R ² _b (OR ³ ) _c SiO _{(4-abc) / 2} (1)
(Wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group, R ² is a monovalent organic group having a functional group, R ³ is an unsubstituted or alkoxy-substituted alkyl group, and a, b, and c are (0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 0 <c ≦ 4, and 0 <a + b + c ≦ 4)

In the above formula (1), the unsubstituted or substituted monovalent hydrocarbon group of R ¹ is preferably one having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms not containing an aliphatic unsaturated bond, such as a methyl group Alkyl groups such as ethyl group, propyl group, butyl group, pentyl group, hexyl group and cyclohexyl group, aryl groups such as phenyl group, tolyl group and naphthyl group, aralkyl groups such as benzyl group and phenylethyl group, etc. Examples thereof include a chloromethyl group, a bromoethyl group, a trifluoropropyl group, a cyanoethyl group and the like in which the hydrogen atom of the group is substituted with a halogen atom, a cyano group or the like.

R ² is a monovalent organic group having a functional group. Examples of the functional group include alkenyl groups such as vinyl group, allyl group, propenyl group, and butenyl group, acrylic group, methacryl group, epoxy group, amino group, amino group. Examples include addition-reactive, condensation-reactive, or radical-reactive functional groups such as alkyl-substituted amino groups, mercapto groups, and α-alkoxycarbonyl groups. Moreover, as monovalent organic group which has such a functional group, following General formula (5)
R ′ − (Z) _x − (5)
(In the formula, R ′ is an alkenyl group such as vinyl group, allyl group, propenyl group, butenyl group, acrylic group, methacryl group, epoxy group, amino group, aminoalkyl-substituted amino group, mercapto group, α-alkoxycarbonyl group, etc. An addition-reactive, condensation-reactive or radical-reactive functional group, Z is an alkylene group having 1 to 10 carbon atoms, in particular 1 to 3 that may be interposed by an etheric oxygen atom, and x is 0 or 1 .)
What is shown by can also be illustrated.

As the unsubstituted or alkoxy-substituted alkyl group for R ³ , for example, a methyl group, an ethyl group, a propyl group, a butyl group, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group, etc. 4 groups are mentioned. a, b, and c are numbers satisfying 0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 0 <c ≦ 4, and 0 <a + b + c ≦ 4, and more preferably 0 ≦ a ≦ 1, 0 ≦ b ≦ It is a number satisfying 1, 2 ≦ c ≦ 4 and 2 ≦ a + b + c ≦ 4.

  Specific examples of such organoalkoxysilanes include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, methylvinyldiethoxysilane, allyltrimethoxysilane, and γ-acryloyloxymethyltrimethoxysilane. , Γ-methacryloyloxypropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxy Examples include silane, γ-mercaptopropyltrimethoxysilane, α- (ethoxycarbonyl) ethyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, and the like. Thus obtained, at least one in one molecule, preferably may be alkoxysiloxane two or more alkoxy groups remain. Two or more kinds of such organoalkoxysilanes or siloxanes can be used. In the case of organoalkoxysiloxane, those having 2 to 150 silicon atoms, particularly 2 to 100 silicon atoms are preferred.

（式中、Ｒ⁴、Ｒ⁵はそれぞれ非置換又は置換の１価炭化水素基、Ｒ⁶は非置換又はアルコキシ置換のアルキル基、Ｘは非置換又は置換の２価有機基又は酸素原子であり、ｄ、ｅ、ｆはそれぞれ０＜ｄ≦２、０≦ｅ≦３、０＜ｆ≦３、かつ０＜ｄ＋ｅ＋ｆ≦４を満たす数であり、ｇは０、１又は２、ｈは１、２又は３であり、かつｇ＋ｈ＝３である。なお、式（２ａ）の基を１分子中に１〜２０個、ＳｉＨ基は１〜５０個含有することが好ましく、またケイ素原子数は１〜１５０、特に１〜１００であることが好ましい。） Next, the alkoxysilyl group-containing organohydrogensilane or siloxane as the component (II) is an essential component for dramatically improving the adhesion of the primer composition of the present invention, and the following average composition formula (2) And an organohydrogensiloxane having a monovalent group represented by the following formula (2a) and a hydrogen atom bonded to a silicon atom (that is, a SiH group) in the molecule.
H _d R ⁴ _e (XSiR ⁵ _g (OR ⁶ ) _h ) _f SiO _{(4-def) / 2} (2)

(Wherein R ⁴ and R ⁵ are each an unsubstituted or substituted monovalent hydrocarbon group, R ⁶ is an unsubstituted or alkoxy-substituted alkyl group, X is an unsubstituted or substituted divalent organic group or an oxygen atom. , D, e, and f are numbers satisfying 0 <d ≦ 2, 0 ≦ e ≦ 3, 0 <f ≦ 3, and 0 <d + e + f ≦ 4, g is 0, 1 or 2, h is 1, 2 or 3 and g + h = 3 In addition, it is preferable that 1 to 20 groups of the formula (2a) and 1 to 50 SiH groups are contained in one molecule, and the number of silicon atoms is 1. -150, especially 1-100 are preferred.)

In the above formula (2), R ⁴ and R ⁵ are each preferably an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms. Are preferable, and examples thereof include the same groups as those described above for R ¹ . The unsubstituted or alkoxy-substituted alkyl group for R ⁶ is preferably an alkyl group having 1 to 4 carbon atoms, and examples thereof include the same groups as R ³ described above. X represents an unsubstituted or substituted divalent organic group or an oxygen atom, and the unsubstituted or substituted divalent organic group preferably has 1 to 10 carbon atoms, particularly 1 to 3 carbon atoms, such as a methylene group, An alkylene group such as an ethylene group, a propylene group or a butylene group, an arylene group such as a phenylene group, a group in which an alkylene group and an arylene group are bonded, a group in which the hydrogen atom of these groups is substituted with a halogen atom, a cyano group, or the like Can be mentioned.

  d, e, and f are 0 <d ≦ 2, 0 ≦ e ≦ 3, 0 <f ≦ 3, and 0 <d + e + f ≦ 4, preferably 0 <d ≦ 1, 1 ≦ e ≦ 2, 0 < It is a number that satisfies f ≦ 1 and 2 ≦ d + e + f ≦ 3. G and h are numbers satisfying g of 0, 1 or 2, h is 1, 2 or 3, and g + h = 3, respectively, preferably g is 0 or 1, and h is 2 or 3. And a number satisfying g + h = 3.

を形成するケイ素原子に結合するものであることが好ましいが、この式（２ａ）の基としてはアルコキシシリルアルキル基が好ましい。このアルコキシシリルアルキル基としては、下記のトリアルコキシシリルアルキル基、アルキルジアルコキシシリルアルキル基等が挙げられるが、これに制限されるものではない。 The monovalent group represented by the above formula (2a) has the following siloxane structure:

It is preferable that it is bonded to the silicon atom that forms, but the group of the formula (2a) is preferably an alkoxysilylalkyl group. Examples of the alkoxysilylalkyl group include, but are not limited to, the following trialkoxysilylalkyl group and alkyldialkoxysilylalkyl group.

などのアルキルジアルコキシシリルアルキル基。 _{- (CH 2) 2 -Si (} OCH 3) 3, - (CH 2) 2 -Si (OC 2 H 5) 3, - (CH 2) 2 -Si (OC 3 H 7) 3, - (CH 2 ) _3- Si (OCH ₃ ) ₃ , — (CH ₂ ) ₃ —Si (OC ₂ H ₅ ) ₃ , — (CH ₂ ) ₃ —Si (OC ₃ H ₇ ) ₃ , trialkoxysilylalkyl groups,

Alkyl dialkoxysilylalkyl groups such as

  The shape of the alkoxysilyl group-containing organohydrogensiloxane represented by the above formula (2) is not particularly limited, and may be any of linear, cyclic, branched, and three-dimensional network.

（式中、Ｒ⁷、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹はそれぞれ非置換又は置換の１価炭化水素基、Ｙは非置換又は置換の２価有機基、Ｒ¹²は非置換又はアルコキシ置換のアルキル基であり、ｋ、ｍ、ｍ’、ｒはそれぞれ０＜ｋ≦２０、０≦ｍ≦２０、１≦ｍ’≦２０、１≦ｒ≦２０を満たす整数であり、ｐは０、１又は２、ｑは１、２又は３であり、かつｐ＋ｑ＝３である。） As the alkoxysilyl group-containing organohydrogensiloxane of the formula (2) described above, those represented by the following general formula (3) or (4) are particularly preferable.

Wherein R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each an unsubstituted or substituted monovalent hydrocarbon group, Y is an unsubstituted or substituted divalent organic group, and R ¹² is unsubstituted or alkoxy. A substituted alkyl group, k, m, m ′, r are integers satisfying 0 <k ≦ 20, 0 ≦ m ≦ 20, 1 ≦ m ′ ≦ 20, 1 ≦ r ≦ 20, and p is 0 1 or 2, q is 1, 2 or 3, and p + q = 3.)

In the above formulas (3) and (4), R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each an unsubstituted or substituted monovalent hydrocarbon group, preferably a carbon number not containing an aliphatic unsaturated bond. 1 to 10, particularly 1 to 6, and specifically, the same groups as the above R ¹ can be mentioned. Further, the unsubstituted or alkoxy-substituted alkyl group for R ¹² is preferably an alkyl group having 1 to 4 carbon atoms, and examples thereof include the same groups as R ³ described above. Y is an unsubstituted or substituted divalent organic group, preferably having 1 to 10 carbon atoms, particularly 1 to 4 carbon atoms, such as an alkylene group such as methylene group, ethylene group, propylene group, butylene group, Examples include an arylene group such as a phenylene group, a group in which an alkylene group and an arylene group are bonded, and a group in which a hydrogen atom of these groups is substituted with a halogen atom, a cyano group, or the like.

  k, m, m ′, and r are integers satisfying 0 <k ≦ 20, 0 ≦ m ≦ 20, 1 ≦ m ′ ≦ 20, 1 ≦ r ≦ 20, respectively, particularly 5 ≦ k ≦ 15, 2 ≦ m ≦ 10. 2 ≦ m ′ ≦ 10, 1 ≦ r ≦ 10, p and q are p is 0, 1 or 2, q is 1, 2 or 3, and p + q = 3, preferably p is 0 or 1, q is 2 or 3, and is a number satisfying p + q = 3.

の好適な例としては、上記式（２ａ）で例示したものと同様のものが挙げられる。 In the above formulas (3) and (4), a group represented by the following formula (2b) corresponding to the group represented by the formula (2a) of the alkoxysilyl group-containing organohydrogensiloxane represented by the above formula (2).

Preferable examples include those similar to those exemplified in the above formula (2a).

  The above-mentioned organohydrogensiloxane having an alkoxysilyl group may be an addition reaction between a corresponding various organohydrogensiloxane and an organoalkoxysilane having an alkenyl group such as a vinyl group or an allyl group in the presence of a platinum catalyst. Can be obtained by equilibrating various organohydrogensiloxanes and organoalkoxysilanes in the presence of an acid catalyst.

  In the present invention, one of the above organohydrogensiloxanes may be used alone, or two or more of these may be used in combination. The amount of component (II) is 100 masses of component (I). 1 to 500 parts by weight, preferably 2 to 200 parts by weight, and if the amount of component (II) is less than 1 part by weight, the film strength of the composition is insufficient and sufficient adhesive strength is obtained. When the amount exceeds 500 parts by mass, the coating film of the composition is brittle and sufficient adhesive strength cannot be obtained.

  In the present invention, the dialkoxytitanium polymer as the component (III) is necessary to condense and cure the primer composition to give air drying and to improve the adhesion between the film and the adherend.

The dialkoxytitanium polymer of the component (III) has the following composition formula (6)
^{R 13 O- [Ti (OR 13} ) 2 -O] n -R 13 (6)
N represents the degree of polymerization, and n is an integer of 2 or more, preferably an integer of 7 or more. The upper limit of n is not particularly limited, but is usually an integer of 100 or less, preferably 50 or less.

R ¹³ is a monovalent hydrocarbon group, preferably one having 1 to 10 carbon atoms, and examples thereof include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group and octyl group. It is done. There is no restriction | limiting in the shape of this monovalent hydrocarbon group, A linear or branched thing may be sufficient.

  The blending amount of such dialkoxytitanium polymer of component (III) is 0.1 to 500 parts by weight, preferably 0.3 to 100 parts by weight with respect to 100 parts by weight of component (III), and (III) When the amount of the component is less than 0.1 parts by mass, the air drying does not proceed, the strength of the film of the composition is insufficient, and sufficient adhesive strength cannot be obtained, and when it exceeds 500 parts by mass, the film of the composition is brittle. Sufficient adhesive strength cannot be obtained.

  The primer composition of the present invention can be obtained by uniformly mixing a predetermined amount of the above-described components (I) to (III). If necessary, hexane, heptane, toluene, xylene, acetone, methyl ethyl ketone, One or two or more solvents selected from ethyl acetate, ethanol, isopropanol, methylene chloride, trichlorethylene and the like may be added for dilution.

  In addition, in order to confirm that the composition is applied as another optional component to the composition of the present invention, various pigments such as inorganic pigments such as carbon, bengara and titanium oxide, or various organic pigments are used. May be added. Various inorganic fillers such as fumed silica, bengara, cerium oxide, titanium oxide and the like may be added to improve the strength and heat resistance of the resulting film. In addition, the addition amount of the said arbitrary component can be made into the arbitrary amount according to the objective in the range which does not prevent the effect of this invention.

  In use, the primer composition of the present invention is applied to the surface of an adherend, and silicone rubber or the like is adhered to the surface to be applied. Particularly when diluted with a solvent, the primer composition is used for 10 to 60 minutes after application. It is preferable to dry it to the extent that it is allowed to adhere to silicone rubber, etc. If the primer layer flows during the processing of this silicone rubber, the coated surface is heated to about 100 to 200 ° C. and baked for about 5 to 60 minutes. Treatment may be performed to adjust the strength of this coating.

  In this case, the primer composition of the present invention is a variety of cured products (silicone rubbers) of high heat conductivity heat curable silicone rubber compositions, particularly high heat conductivity heat curable silicone rubber compositions containing a heat conductive filler. It can be effectively used for bonding to an adherend, and in particular, the content of the heat conductive filler is 100 parts by weight or more, preferably 100 to 1,000 parts by weight with respect to 100 parts by weight of the composition excluding the heat conductive filler. It is effective for adhering some silicone rubber. Further, as the adherend, for example, metals such as iron, aluminum, stainless steel, nickel, zinc, tin-plated steel plate, various plastics, and the like can be used. Furthermore, it is highly effective for fluororesins, and can be suitably used when the adherend is a fluororesin.

  Here, in particular, as the heat-curable silicone rubber composition that gives a highly heat-conductive silicone rubber to which the primer composition of the present invention is effectively applied, an organic peroxide-curable silicone rubber composition, an addition-curable silicone rubber composition Products, condensation curable silicone rubber compositions and the like, and addition curable silicone rubber compositions are preferred. Various fillers having thermal conductivity can be used as a filler in the silicone rubber composition that gives such a high thermal conductivity silicone rubber. Specific examples include quartz powder, diatomaceous earth, aluminum oxide (alumina), aluminum hydroxide, zinc oxide, silicon carbide, silicon nitride, magnesium oxide, aluminum nitride, boron nitride, etc., especially quartz powder, alumina and zinc oxide. Are preferably used.

  The silicone rubber composition further includes reinforcing silica fillers such as silica hydrogel (hydrous silicic acid), silica airgel (anhydrous silicic acid-fumed silica), clay, calcium carbonate, titanium dioxide and the like as necessary. Addition and mixing heat resistance improver such as filler, iron oxide, cerium oxide, iron octylate, various carbon functional silanes to improve adhesion and moldability, nitrogen compounds to give flame retardancy, halogen compounds May be.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In the following examples, the viscosity indicates a measured value at 23 ° C.

Preparation of high thermal conductive liquid silicone rubber composition (1):
Hydrophobized fumed silica having 100 parts by weight of a dimethylsiloxane polymer having both ends blocked with trimethylsiloxy groups and vinyl groups in the side chains and a viscosity of about 15 Pa · s, and a specific surface area of 110 cm ² / g (R-972, manufactured by Nippon Aerosil Co., Ltd.) 0.7 parts by weight, 200 parts by weight of quartz powder (trade name Crystallite A-1, manufactured by Tatsumori Co., Ltd.) having an average particle size of 12 μm was placed in a planetary mixer. Stirring was performed at room temperature (23 ° C.) for 2 hours. The mixture was spread on three rolls to disperse the filler, and then returned to the planetary mixer, and 3 parts by mass of hydrogen methylpolysiloxane having a viscosity represented by the following formula (i) of 0.01 Pa · s. As a reaction control agent, 0.1 part by mass of ethynylcyclohexanol and 0.1 part by mass of a platinum catalyst (Pt concentration 1%) were added and stirred for 15 minutes, and the resulting composition was designated as liquid rubber composition 1. This liquid rubber composition 1 was press-cured at 120 ° C. for 10 minutes and post-cured at 200 ° C. for 4 hours. The thermal conductivity of the obtained cured product was measured. The thermal conductivity was 0.7 W / m · ° C.

Preparation of highly heat conductive liquid silicone rubber composition (2):
Except for changing 200 parts by mass of quartz powder to 300 parts by mass of aluminum oxide (alumina AS-30, Showa Denko Co., Ltd.) having an average particle diameter of 18 μm, the same as the preparation (1) of the above highly heat conductive liquid silicone rubber composition Thus, a composition was prepared, which was designated as Liquid Rubber Composition 2. Liquid rubber composition 2 was press-cured at 120 ° C. for 10 minutes and post-cured at 200 ° C. for 4 hours. The thermal conductivity of the obtained cured product was measured. The thermal conductivity was 0.75 W / m · ° C.

Preparation of highly heat conductive liquid silicone rubber composition (3):
A composition was prepared in the same manner as in the preparation (1) of the above highly heat-conductive liquid silicone rubber composition, except that 200 parts by mass of quartz powder was changed to 300 parts by mass of calcined zinc oxide (manufactured by Hakusui Tech Co., Ltd.) having an average particle diameter of 10 μm. This was prepared as a liquid rubber composition 3. Liquid rubber composition 3 was press-cured at 120 ° C. for 10 minutes and post-cured at 200 ° C. for 4 hours. The thermal conductivity of the obtained cured product was measured. The thermal conductivity was 0.72 W / m · ° C.

[Example 1]
100 parts by mass of tetraethoxysilane, 50 parts by mass of methylhydrogensiloxane having a trimethoxysilyl group having a viscosity of 0.015 Pa · s represented by the following formula (ii) and tetra-n-butoxytitanium represented by the following formula (iii) A primer composition 1 was prepared by mixing 50 parts by mass of polymer B-10 (manufactured by Nippon Soda Co., Ltd.), adding 1,000 parts by mass of heptane and mixing well.

[Comparative Example 1]
For comparison, a primer was prepared in the same manner as in Example 1 except that 50 parts by mass of the tetra-n-butoxytitanium polymer B-10 (Nippon Soda Co., Ltd.) of the above formula (iii) was changed to tetrabutyl titanate. Composition 2 was prepared.

  After applying the primer compositions 1 and 2 to a PFA resin film placed with the surface treated with liquid ammonia as the upper surface, the liquid rubber composition 1 was poured and uniformly applied to a thickness of 2 mm. This uncured integrated product was cured by heating at 100 ° C. for 15 minutes, and further heated at 200 ° C. for 4 hours to obtain a product that was firmly integrated with the PFA resin film. The obtained integrally molded product was cut into a strip shape (length 50 mm × width 5 mm × thickness 2 mm) to prepare a test piece. A cut was made with a knife at the center (25 mm from the end) from the silicone rubber layer side of the test piece of the integrally molded product, and pulled on both sides to examine the adhesion of the integrally molded product. The results are shown in Table 1.

[Example 2]
100 parts by mass of tetraethoxysilane, 50 parts by mass of vinyltriethoxysilane, 50 parts by mass of methylhydrogensiloxane having a trimethoxysilyl group having a viscosity of 0.015 Pa · s represented by the following formula (iv), and the above formula (iii) A primer composition 3 was prepared by mixing 50 parts by mass of tetra-n-butoxytitanium polymer B-10 (manufactured by Nippon Soda Co., Ltd.), adding 1,000 parts by mass of heptane and mixing well.

[Comparative Example 2]
For comparison, a primer was prepared in the same manner as in Example 2 except that 50 parts by mass of tetra-n-butoxytitanium polymer B-10 (Nippon Soda Co., Ltd.) of the above formula (iii) was changed to tetrabutyl titanate. Composition 4 was prepared.

  After applying the primer compositions 3 and 4 to a PFA resin film placed with the surface treated with liquid ammonia as the upper surface, the liquid rubber composition 2 was flowed and uniformly applied with a thickness of 2 mm. This uncured integrated product was cured by heating at 100 ° C. for 15 minutes, and further heated at 200 ° C. for 4 hours to obtain a product that was firmly integrated with the PFA resin film. The obtained integrally molded product was cut into a strip shape (length 50 mm × width 5 mm × thickness 2 mm) to prepare a test piece. A cut was made with a knife at the center (25 mm from the end) from the silicone rubber layer side of the test piece of the integrally molded product, and pulled on both sides to examine the adhesion of the integrally molded product. The results are shown in Table 1.

Claims (6)

A primer composition for adhering silicone rubber to metal or plastic,
( I) The following average composition formula (1)
R ¹ _a R ² _b (OR ³ ) _c SiO _{(4-abc) / 2} (1)
(Wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group, R ² is a monovalent organic group having a functional group, R ³ is an unsubstituted or alkoxy-substituted alkyl group, and a, b, and c are (0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 0 <c ≦ 4, and 0 <a + b + c ≦ 4)
100 parts by mass (II) The following average composition formula (2)
H _d R ⁴ _e (XSiR ⁵ _g (OR ⁶ ) _h ) _f SiO _{(4-def) / 2} (2)
(Wherein R ⁴ and R ⁵ are each an unsubstituted or substituted monovalent hydrocarbon group, R ⁶ is an unsubstituted or alkoxy-substituted alkyl group, X is an unsubstituted or substituted divalent organic group or an oxygen atom. , D, e, and f are numbers satisfying 0 <d ≦ 2, 0 ≦ e ≦ 3, 0 <f ≦ 3, and 0 <d + e + f ≦ 4, g is 0, 1 or 2, h is 1, 2 or 3 and g + h = 3.)
A primer composition for silicone rubber, comprising 1 to 500 parts by mass of an alkoxysilyl group-containing organohydrogensilane or siloxane represented by formula (III) dialkoxytitanium polymer 0.1 to 500 parts by mass. The alkoxysilyl group-containing organohydrogensiloxane as the component (II) is represented by the following general formula (3) or (4)

Wherein R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each an unsubstituted or substituted monovalent hydrocarbon group, Y is an unsubstituted or substituted divalent organic group, and R ¹² is unsubstituted or alkoxy. A substituted alkyl group, k, m, m ′, r are integers satisfying 0 <k ≦ 20, 0 ≦ m ≦ 20, 1 ≦ m ′ ≦ 20, 1 ≦ r ≦ 20, and p is 0 1 or 2, q is 1, 2 or 3, and p + q = 3.)
The primer composition of Claim 1 which is shown by these. The component (III) dialkoxytitanium polymer has the following compositional formula (6):
R ¹³ O- [Ti (OR ¹³ ) ₂ -O] _n -R ¹³             (6)
(Wherein R ¹³ Is a monovalent hydrocarbon group having 1 to 10 carbon atoms, and n is an integer of 2 to 100. )
The primer composition of Claim 1 or 2 which is shown by these. The silicone rubber is a cured product of a highly thermally conductive thermosetting silicone rubber composition containing 100 to 1,000 parts by mass of a thermally conductive filler with respect to 100 parts by mass of the composition excluding the thermally conductive filler. Item 4. The primer composition according to any one of Items 1 to 3. A method for adhering silicone rubber, comprising applying the primer composition according to any one of claims 1 to 3 to a surface of a metal or plastic adherend, and adhering silicone rubber onto the primer composition. The silicone rubber is a cured product of a highly thermally conductive thermosetting silicone rubber composition containing 100 to 1,000 parts by mass of a thermally conductive filler with respect to 100 parts by mass of the composition excluding the thermally conductive filler. Item 6. The method for bonding silicone rubber according to Item 5.