JP6740917B2 - Primer composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel primer composition capable of favorably adhering a silicone rubber and an adherend, and more specifically, an alkoxytitanium and a hydrolyzable silyl group-containing β-ketoester, and at least two of them in a molecule. The present invention relates to a primer composition containing an organopolysiloxane resin having a three-dimensional network structure containing various types of constitutional units and capable of adhering a condensation-curing type silicone rubber to various adherends.

Since silicone rubber has excellent heat resistance, cold resistance, and UV resistance, it is generally widely used for electrical insulation materials, electronic component materials such as potting materials, and construction sealing materials. In order to adhere to an adherend, a method of applying various primer compositions to an adherend is adopted.

Conventionally, silane coupling agents and their condensates, their reaction products, and organotitanium compounds such as alkoxytitanium and titanate coupling agents are known as primer compositions for condensation-curing type silicone rubbers. (Patent Documents 1 to 3). However, the silane coupling agent and the alkoxytitanium used as the above-mentioned adhesive component each independently exert an adhesive action and do not have complementary roles to each other, and therefore the adhesiveness is insufficient. There is.
Further, as a primer capable of complementarily drawing out the adhesiveness between the alkoxytitanium and the silane coupling agent and adhering the silicone rubber to various adherends well, the alkoxytitanium and the hydrolyzable silyl group-containing β-ketoester can be used. A composition containing a titanium compound which is a reaction product has been proposed, but the adhesiveness was not sufficiently exhibited after water immersion because of poor film forming property (Patent Document 4).

Japanese Patent Publication No. 61-2107 JP, 11-209702, A JP, 2006-131830, A JP, 2016-069290, A

Therefore, the object of the present invention is to draw out the adhesiveness of each of the alkoxytitanium and the silane coupling agent complementarily, and to have good film-forming properties, and to apply silicone rubber to various adherends well even under the condition after water immersion. It is to provide a primer composition that can be adhered.

As a result of intensive studies on the above problems, the present inventors have found that by using a silicone resin (resin) having a specific structure as a primer component, the silicone rubber is suitable for various adherends even under the condition after water immersion. The present invention has been completed by finding that it can be adhered to

That is, the present invention provides the following primer composition .

<1>
(A) organic titanium compound,
(B) A three-dimensional network-structured organopolysiloxane resin composed of siloxane M units and siloxane Q units and containing 0.01 mol/100 g or more and less than 0.20 mol/100 g of silicon atom-bonded hydroxy groups. as well as
(C) solvent
A primer composition comprising
The above-mentioned (A) organotitanium compound has an average composition formula (I):
Ti(OR ¹ ) _4-a (Y ₃ Si-A-O-CO-CH=C(O)R) _a (I)
(In the formula, R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms; ¹ Is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, A is a divalent hydrocarbon group having 1 to 6 carbon atoms, Y is a hydrolyzable group, and a is 0.1 ≦a≦2)
A primer composition represented by:

<2>
The primer composition according to <1>, wherein the component (B) contains 0.02 to 0.10 mol/100 g of a hydroxy group bonded to a silicon atom.

<3>
The (A) organotitanium compound is
(A1) The following general formula (1):

(In the formula (1), R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, A is a divalent hydrocarbon group having 1 to 6 carbon atoms, and Y is a hydrolyzable group. It is.)
And a hydrolyzable silyl group-containing β-keto ester represented by
(A2) The following general formula (2):

(In the formula (2), R ¹ Is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms. )
Which is a reaction product with tetraalkoxytitanium, wherein (A1) the hydrolyzable silyl group-containing β-ketoester has an average coordination number of 0.1 to 2 with respect to titanium, < 1> or the primer composition described in <2>.

<4>
Content of the said (A) component is 1-30 mass parts with respect to 100 mass parts of said (C) components, The primer composition of any one of <1>-<3> characterized by the above-mentioned. Stuff.

< 5 >
Content of the said (B) component is 0.5-10 mass parts with respect to 100 mass parts of said (C) components, It is any one of <1>-< 4 > characterized by the above-mentioned. Primer composition.

< 6 >
The component (C) is any one kind or a mixture of two or more kinds selected from aromatic hydrocarbon solvents, alcohol solvents, ketone solvents, ether solvents, ester solvents and paraffin solvents. The primer composition according to any one of <1> to < 5 >, which is characterized.

< 7 >
The primer composition according to < 6 >, wherein the component (C) is an aromatic hydrocarbon solvent or a paraffin solvent.

< 8 >
The primer composition according to any one of <1> to < 7 >, wherein the primer composition is for adhering silicone rubber to an adherend.

< 9 >
The primer composition according to < 8 >, wherein the silicone rubber is a condensation curing type room temperature curable silicone rubber.

< 10 >
Any of < 3 > to < 9 >, wherein (A1) a hydrolyzable silyl group-containing β-ketoester is reacted with (A2) tetraalkoxytitanium in the components (B) and (C). Item 1. A method for producing the primer composition according to item 1.

The primer composition of the present invention can favorably adhere silicone rubber to various adherends even under the condition after water immersion.

Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.
[Primer composition]
As described above, the primer composition of the present invention is
(A) organic titanium compound,
(B) a three-dimensional network-structured organopolysiloxane resin containing at least two kinds of structural units in the molecule, and
(C) Contains a solvent.

The primer composition of the present invention can be prepared by uniformly mixing the following components (A), (B) and (C), and optionally the following other components.

[(A)) ingredient]
The organic titanium compound as the component (A) is, as described above,
Average composition formula (I):
Ti(OR ¹ ) _4-a (Y ₃ Si-AO-CO-CH=C(O)R) _a (I)
(In the formula, R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, and A is a carbon atom. Which is a divalent hydrocarbon group of the formulas 1 to 6, Y is a hydrolyzable group, and a is a number of 0.1≦a≦2)
It is represented by.

The component (A) is represented by the following general formula (1):

(In the formula, R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, A is a divalent hydrocarbon group having 1 to 6 carbon atoms, preferably 3 to 6 carbon atoms, and Y is It is a hydrolyzable group.)
And a hydrolyzable silyl group-containing β-keto ester represented by
(A2) The following general formula (2):

(In the formula, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms.)
The reaction product with tetraalkoxy titanium represented by the formula (A1) has an average coordination number of 0.1 to 2, preferably 0.5 to 2.0 of (A1) hydrolyzable silyl group-containing β-keto ester with respect to titanium. , And more preferably 0.7 to 1.8.

Here, in the above general formulas (I) and (1), the substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms is a methyl group, an ethyl group, a propyl group, an isopropyl group. , Butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group, decyl group, dodecyl group and other alkyl groups; cyclopentyl group, cyclohexyl group and other cyclo groups Alkyl group; alkenyl group such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, pentenyl group, hexenyl group, cyclohexenyl group; phenyl group, tolyl group, xylyl group, α-, β-naphthyl group, etc. Aryl groups; aralkyl groups such as benzyl group, 2-phenylethyl group, 3-phenylpropyl group; and some or all of hydrogen atoms of these groups are halogen atoms such as F, Cl, Br, and cyano groups. And the like, for example, 3-chloropropyl group, 3,3,3-trifluoropropyl group, 2-cyanoethyl group and the like. Among these, a lower alkyl group having 1 to 4, more preferably 1 to 3, and especially 1 to 2 carbon atoms such as a methyl group and an ethyl group is preferable, and a methyl group is particularly preferable.

In the above general formulas (I) and (1), among the divalent hydrocarbon groups having 1 to 6 carbon atoms, preferably 3 to 6 carbon atoms represented by A, the divalent hydrocarbon group having 1 to 6 carbon atoms is It is preferably a saturated aliphatic divalent hydrocarbon group such as a linear alkylene group represented by —(CH ₂ ) _p — (p is 1 to 6) or a branched alkylene group, _{(CH 2)} p - (p is a is 3-6) is more preferably a linear alkylene group represented by. Among them, - _{(CH 2) 3} - is preferable.

In the above general formulas (I) and (1), Y is a hydrolyzable group, for example, an alkoxy group such as a methoxy group, an ethoxy group and a propoxy group; an alkoxy group such as a methoxyethoxy group, an ethoxyethoxy group and a methoxypropoxy group. Alkoxy group: Acyloxy group such as acetoxy group, octanoyloxy group, benzoyloxy group; Alkenyloxy group such as vinyloxy group, allyloxy group, propenyloxy group, isopropenyloxy group, 1-ethyl-2-methylvinyloxy group; Ketoxime groups such as dimethylketoxime group, methylethylketoxime group and diethylketoxime group; amino groups such as dimethylamino group, diethylamino group, butylamino group, cyclohexylamino group; aminoxy groups such as dimethylaminoxy group and diethylaminoxy group; Examples thereof include amide groups such as N-methylacetamide group, N-ethylacetamide group and N-methylbenzamide group. Among these, an alkoxy group is preferable, and a lower alkoxy group having 1 to 4 carbon atoms, such as a methoxy group and an ethoxy group, more preferably 1 to 3 carbon atoms, especially 1 to 2 carbon atoms is preferable.

Next, in the above general formulas (I) and (2), the substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms represented by R ¹ is a methyl group, an ethyl group, a propyl group or isopropyl group. Group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group, decyl group, dodecyl group and other alkyl groups; cyclopentyl group, cyclohexyl group, etc. Cycloalkyl group; alkenyl group such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, pentenyl group, hexenyl group, cyclohexenyl group; phenyl group, tolyl group, xylyl group, α-, β-naphthyl group Aryl groups such as benzyl, aralkyl groups such as benzyl, 2-phenylethyl, and 3-phenylpropyl; some or all of the hydrogen atoms of these groups are halogen atoms such as F, Cl, Br, and cyano. Examples thereof include groups substituted with a group such as a 3-chloropropyl group, a 3,3,3-trifluoropropyl group and a 2-cyanoethyl group. Among these, a lower alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group and an isopropyl group is preferable, and an isopropyl group is particularly preferable.

Preparation of (A1) The above-mentioned (A1) hydrolyzable silyl group-containing β-keto ester represented by the general formula (1) is, for example, the following general formula (3):

（式中、Ｒは前記の通りであり、Ａ^１は炭素数１〜４の二価炭化水素基である）
で表される不飽和脂肪族基含有β−ケトエステルと、
下記一般式（４）：

(In the formula, R is as described above, and A ¹ is a divalent hydrocarbon group having 1 to 4 carbon atoms.)
An unsaturated aliphatic group-containing β-keto ester represented by
The following general formula (4):

（式中、Ｙは前記の通りである）
で表される加水分解性シラン化合物とを反応させる等、公知の方法（特開２００５-３１４３２５号公報）を参照して調製することができる。なお、Ａ^１は、一般式（１）中のＡからエチレン基（−（ＣＨ_２）_２−）を除いた基に該当する。

(In the formula, Y is as described above)
It can be prepared by referring to a known method (Japanese Patent Application Laid-Open No. 2005-314325), such as a reaction with a hydrolyzable silane compound represented by Note that A ¹ corresponds to a group obtained by removing the ethylene group (—(CH ₂ ) ₂ —) from A in the general formula (1).

In the general formula (3), the divalent hydrocarbon group having 1 to 4 carbon atoms represented by A ¹ is a linear alkylene group or a branched alkylene group represented by —(CH ₂ ) _p —. it is preferably a saturated aliphatic divalent hydrocarbon group such _{as, - (CH 2) p -} (p is 1-4) is more preferably a linear alkylene group represented by. Among them, - (CH ₂₎ - are preferred.

The content of the component (A) is preferably 1 to 30 parts by mass, more preferably 1 to 20 parts by mass, and 2 to 15 parts by mass with respect to 100 parts by mass of the component (C). It is more preferable that the amount is 5 to 10 parts by mass.
In the primer composition of the present invention, the component (A) is preferably contained in an amount of 1 to 20% by mass, more preferably 2 to 15% by mass, and further preferably 5 to 10% by mass.

The organotitanium compound as the component (A) may be prepared in advance before formulation of the primer composition, or may be prepared in-system at the time of formulation of the primer composition. That is, (A1) a hydrolyzable silyl group-containing β-ketoester and (A2) a tetraalkoxytitanium reaction product (A) an organotitanium compound are mixed with a component (B) and a component (C) to prepare a primer composition. In addition, the component (B) and the component (C), (A1) hydrolyzable silyl group-containing β-keto ester and (A2) tetraalkoxytitanium is reacted to produce (A) an organotitanium compound. The primer composition may be included.

[(B) component]
The organopolysiloxane resin as the component (B) contains T units (trifunctional organosilsesquioxane units) and/or Q units (tetrafunctional SiO _4/2 units), and the T units and And/or at least one siloxane unit selected from M units (monofunctional triorganosiloxy units) and D units (difunctional diorganosiloxane units) as constitutional units other than Q units. An organopolysiloxane resin (so-called silicone resin) having a three-dimensional network structure containing at least two types of structural units is preferable. For example, an MQ resin containing R ² ₃ SiO _1/2 units (M units) and SiO _4/2 units (Q units) as main components, R ² SiO _3/2 units (T units), and R ² ₂ SiO _{2 /2} unit (D unit) as a main component, MD unit consisting of M unit, D unit and Q unit, MDT resin consisting of M unit, D unit and T unit, and M unit, D unit, T Examples thereof include MDTQ resin composed of units and Q units. In the above, R ² is, independently of each other, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, a hydroxyl group, and a hydrolyzable group having 1 to 6 carbon atoms. The monovalent hydrocarbon group, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl Group, alkyl group such as decyl group, dodecyl group; cycloalkyl group such as cyclopentyl group, cyclohexyl group; vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, pentenyl group, hexenyl group, cyclohexenyl group, etc. Alkenyl group; aryl group such as phenyl group, tolyl group, xylyl group, α-, β-naphthyl group; aralkyl group such as benzyl group, 2-phenylethyl group, 3-phenylpropyl group; hydrogen of these groups A group in which some or all of the atoms are substituted with a halogen atom such as F, Cl, Br, or a cyano group, for example, a 3-chloropropyl group, 3,3,3-trifluoropropyl group, 2-cyanoethyl group Etc. can be illustrated. Examples of the hydrolyzable group include alkoxy groups such as methoxy group and ethoxy group. However, at least one of R ² is a hydroxyl group or a hydrolyzable group. In the present invention, MQ resin is most preferable as the organopolysiloxane resin.

In the organopolysiloxane resin as the component (B), the ratio of T units and/or Q units to all the constituent units is 45 to 65 mol %, preferably 50 to 65 mol %.
In particular, in the MQ resin, the molar ratio of M units to Q units is 0.6 to 1.2, preferably 0.6 to 1.0, and the MQ resin is a hydroxy group bonded to a silicon atom. The group (silanol group) is preferably less than 0.20 mol/100 g, and the lower limit is preferably 0.01 mol/100 g or more. The content of hydroxy groups bonded to silicon atoms is particularly preferably 0.02 to 0.10 mol/100 g. The MQ resin may contain a small amount of T units and/or D units.

The content of the component (B) is preferably 0.5 to 10 parts by mass, more preferably 0.7 to 7 parts by mass, and 1 to 5 with respect to 100 parts by mass of the component (C). It is more preferably part by mass, and particularly preferably 1 to 3 parts by mass.

[(C) component]
The solvent of the component (C) may be any solvent as long as it dissolves each component in the primer composition at an arbitrary ratio and is volatile at the same time. Specifically, for example, aromatic hydrocarbon solvents such as benzene, toluene and xylene; alcohol solvents such as methanol, ethanol, isopropyl alcohol and ethylene glycol monomethyl; ketone solvents such as acetone and methyl ethyl ketone; Examples thereof include ester solvents such as ligroin and ethyl acetate; ether solvents such as tetrahydrofuran and dioxane; and paraffin solvents such as hexane and cyclohexane. These may be used alone or as a mixed solvent of two or more kinds. Can also be used. Among these, aromatic hydrocarbon solvents or paraffin solvents are preferable, and toluene and hexane are particularly preferable.

[Other ingredients]
The primer composition of the present invention may contain, in addition to the above-mentioned components, one or more kinds of silane coupling agents, metal alkoxides and the like, as long as the object of the present invention is not impaired. Examples of the silane coupling agent include alkenyl functional group-containing alkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane; γ-aminopropyltriethoxysilane, and 3-2-( Aminoethylamino)propyltrimethoxysilane and other aminofunctional group-containing alkoxysilanes; γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and other epoxy functional group-containing Examples thereof include alkoxysilanes; or silane coupling agents (carbon functional functional group-containing hydrolyzable silanes) such as isocyanate functional group-containing alkoxysilanes. These silane coupling agents can be added in an amount of 0 to 20% by mass, particularly 0 to 5% by mass, based on the entire primer composition. Examples of the metal alkoxide include zirconium alkoxides represented by zirconium tetraalkoxides such as zirconium tetrapropoxide, zirconium tetra-n-butoxide, and zirconium tetra-tert-butoxide. The amount of the metal alkoxide compounded is 0 to 20% by mass, particularly 0 to 10% by mass, based on the entire primer composition.

The primer composition of the present invention has no curability by itself, and therefore, for example, a hydroxyl group (silanol group) bonded to at least two silicon atoms and/or a silicon atom bond in the molecule. A room-temperature-curable linear room-temperature-curable resin that has a room-temperature-curable functional group selected from hydrolyzable groups at the both ends of its molecular chain is liquid before curing. It is essentially different from the so-called room temperature curable organopolysiloxane composition (RTV silicone rubber composition) in that it does not contain a resin component.

The primer composition of the present invention contains a hydrolyzable silyl group-containing β-ketoester, which is a metal coordinating silane coupling agent, and an organotitanium compound, which is a reaction product of tetraalkoxytitanium, to thereby provide a metal coordinating compound. Of the adhesive silane coupling agent and the alkoxytitanium are complementarily drawn out, and in particular, condensation-curable silicone rubber, preferably room-temperature-curable silicone rubber, is applied to various adherends (for example, glass such as flow glass). Substrate; metal substrate made of aluminum, alumite, copper, stainless steel, etc.; resin substrate such as polycarbonate resin; metal substrate coated with acrylic electrodeposition coating or fluorine resin coating) .. Furthermore, the primer composition of the present invention contains the organopolysiloxane resin having high rigidity, so that good adhesiveness can be maintained even under deterioration conditions such as water immersion.
The condensation-curable silicone rubber has a curable functional group selected from a hydroxyl group (silanol group) bonded to at least two silicon atoms or a hydrolyzable group in the molecule, and preferably at 25° C. The viscosity is 100 to 1,000,000 mPa·s, more preferably 300 to 500,000 mPa·s, particularly preferably 500 to 100,000 mPa·s, and particularly 1,000 to 80,000 mPa·s. Here, the viscosity is a numerical value measured by a rotational viscometer (Brookfield type viscometer).

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following specific examples, “part” means “part by mass”.

[Example 1]
MQR-85T (manufactured by Shin-Etsu Chemical Co., Ltd., MQ/0.75 (molar ratio)) which is MQ resin (organopolysiloxane resin having a three-dimensional network structure) in 100 parts of hexane (manufactured by Kanto Chemical Co., Inc.) , OH value: 0.06 mol/100 g) and 5 parts of tetrabutyl orthotitanate (manufactured by Tokyo Chemical Industry Co., Ltd.) were charged and stirred for 4 hours. Next, 3 parts of trimethoxysilylpropyl acetoacetate, which is a reaction product (molar ratio 1:1) of allyl acetoacetate and trimethoxysilane, (however, containing trace amounts of impurities such as isomers. , The same.) is added dropwise and the mixture is stirred for 1 hour to react the tetraalkoxytitanium with the hydrolyzable silyl group-containing β-ketoester in the mixed solution, and the average coordination number a in the average composition formula (I) is calculated. To give a pale yellow primer composition 1 containing a reaction product corresponding to about 0.78.

[Comparative Example 1]
A primer composition 2 was obtained in the same manner as in Example 1 except that 2 parts of a silicate 40 (manufactured by Tama Chemical Industry Co., Ltd.), which is a Q resin, was charged instead of the MQ resin.

[Comparative Example 2]
A primer composition 3 was obtained in the same manner as in Example 1 except that 2 parts of KC-89E (manufactured by Shin-Etsu Chemical Co., Ltd.), which was a T resin, was used instead of the MQ resin.

[Comparative Example 3]
A primer composition 4 was obtained in the same manner as in Example 1 except that the MQ resin was not added.

[Test example]
The primer compositions 1 to 4 prepared in the above Examples and Comparative Examples were prepared by applying an adherend having a width of 50 mm and a length of 50 mm (float glass, alumite, a fluororesin-coated aluminum substrate, acrylic electrodeposition-coated aluminum (matte), A thin coating was applied by brush coating on acrylic electrodeposition-coated aluminum (lustered), and a tensile adhesion test was conducted according to JIS A-1439 using a condensation curing type room temperature curable silicone sealing material. The initial curing conditions were 23° C. and 50% RH for 7 days, and then 50° C. for 7 days to perform the test. The post-immersion curing conditions were the initial curing conditions, and the test was conducted after further immersing in warm water at 50° C. for 7 days.

The results are shown in Table 1 below. A sealant 70 (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the condensation curing type room temperature curable silicone sealing material.

As shown in Table 1, the primer composition 1 of Example 1 containing MQ resin exhibited higher adhesive strength and higher cohesive failure rate even after flooding, as compared with the primer compositions 2 to 4 of Comparative Examples 1 to 3. Indicated.

From the above, a specific organotitanium compound, which is a reaction product of tetraalkoxytitanium and a hydrolyzable silyl group-containing β-ketoester, and a polyorganosiloxane resin composed of M units and Q units having favorable film-forming properties are contained. It is shown that the primer composition of the present invention has better adhesiveness after the water immersion test than when the organopolysiloxane resin composed of a single constitutional unit is used and when the organopolysiloxane resin is not added. Was done.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the invention having substantially the same configuration as the technical idea described in the scope of the claims of the present invention and exhibiting the same action and effect is the present invention Within the technical scope of.

Claims (10)

(A) organic titanium compound,
(B) Organopolysiloxane resin having a three-dimensional network structure , which is composed of siloxane M units and siloxane Q units, and further contains 0.01 mol/100 g or more and less than 0.20 mol/100 g of a hydroxy group bonded to a silicon atom. as well as
(C) a primer composition containing a solvent,
The above-mentioned (A) organotitanium compound has an average composition formula (I):
Ti(OR ¹ ) _4-a (Y ₃ Si-AO-CO-CH=C(O)R) _a (I)
(In the formula, R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, and A is a carbon atom. Which is a divalent hydrocarbon group of the formulas 1 to 6, Y is a hydrolyzable group, and a is a number of 0.1≦a≦2)
A primer composition represented by: The primer composition according to claim 1, wherein the component (B) contains 0.02 to 0.10 mol/100 g of a hydroxy group bonded to a silicon atom. The (A) organotitanium compound is
(A1) The following general formula (1):

(In the formula (1), R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, A is a divalent hydrocarbon group having 1 to 6 carbon atoms, and Y is a hydrolyzable group. It is.)
And a hydrolyzable silyl group-containing β-keto ester represented by
(A2) The following general formula (2):

(In the formula (2), R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms.)
Which is a reaction product with tetraalkoxytitanium, wherein the average coordination number of titanium of the (A1) hydrolyzable silyl group-containing β-ketoester is 0.1 to 2, The primer composition according to claim 1 or 2 . Content of the said (A) component is 1-30 mass parts with respect to 100 mass parts of said (C) component, The primer composition of any one of Claims 1-3 characterized by the above-mentioned. Content of the said (B) component is 0.5-10 mass parts with respect to 100 mass parts of the said (C) component, The primer composition of any one of Claims 1-4 characterized by the above-mentioned. Stuff. The component (C) is any one kind or a mixture of two or more kinds selected from aromatic hydrocarbon solvents, alcohol solvents, ketone solvents, ether solvents, ester solvents and paraffin solvents. the primer composition according to any one of claims 1 to 5, wherein. The primer composition according to claim 6 , wherein the component (C) is an aromatic hydrocarbon solvent or a paraffin solvent. The primer composition is for adhering silicone rubber to an adherend, the primer composition according to any one of claims 1-7. The primer composition according to claim 8 , wherein the silicone rubber is a condensation curing type room temperature curable silicone rubber. (B) a component and (C) component, (A1) to any one of claims 3-9 which comprises reacting a hydrolyzable silyl group-containing β- ketoester and a (A2) tetraalkoxy titanium A method for producing the primer composition according to item 1.