JP2734297B2 - Adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention is initially tacky,
More specifically, the present invention relates to a silicone-based adhesive composition that cures under moisture conditions.
The present invention relates to an adhesive composition suitable for applications such as sealing and adhesives for potting, potting and construction, and seals and adhesives for automobile engine parts.

[0002]

2. Description of the Related Art Silicone rubber is widely used in the electrical and electronic industries, the construction industry, the automobile industry, the office equipment industry, etc. because of its characteristics such as heat resistance and weather resistance. Have been.

In addition to such uses, in recent years, a method in which a silicone rubber molded article is adhered to an adherend and used is generally used. Particularly in the construction industry, a silicone rubber gasket material is used as a waterproof sealing material for buildings. It has come to be used as.

[0004] Silicone rubber gaskets are more resistant to weathering than gaskets made of other synthetic rubber materials.
In addition to having excellent properties such as flame retardancy, it has a small compression set, and has excellent properties as a waterproof sealing material for buildings requiring long-term reliability. Demand is soaring.

[0005] These architectural gaskets are produced by a method such as extrusion molding of a known silicone rubber composition, and are used as solid or sponge gaskets. These silicone rubber gaskets are used as waterproof sealing materials for building exterior wall panels such as metal curtain walls, concrete curtain walls, aluminum sashes, ALC panels, and the like. Is used.

[0006] This silicone sealant is a moisture-curing type, and requires a considerable amount of time to cure. In practice, a silicone rubber gasket must be adhered to the outer wall using a silicone sealant and the silicone rubber must be adhered to the outer wall for at least one day. Since the rubber gasket cannot be firmly adhered to the outer wall panel, the outer wall panel cannot be moved immediately, resulting in a very low factory productivity, and an improvement has been desired.

On the other hand, a pressure-sensitive adhesive containing an organopolysiloxane has an M unit represented by R ₃ SiO _1/2 and SiO 2
_{As a} composition consisting essentially of a mixture of a solvent-soluble copolymer consisting of Q units represented by _4/2 and a hydroxy-terminated organopolysiloxane, U.S. Pat.
No. 736,721, No. 2,814,601, No. 3,5
28,940 and the like. Japanese Patent Publication No. 54-37907 discloses a solvent-soluble copolymer consisting essentially of M units and Q units, an organopolysiloxane containing alkenyl groups, and an organopolysiloxane containing hydrogen atoms bonded to silicon. An adhesive of the type that cures a composition obtained by blending with a platinum-containing catalyst has been proposed.

However, these adhesives also have tackiness at the initial stage, but have a problem that heating at 80 ° C. to 150 ° C. is required in order to develop tackiness or adhesive strength. Improvement was desired.

The present invention has been made in view of the above circumstances,
An object of the present invention is to provide a silicone-based adhesive composition which has an initial tackiness, can be bonded in a short time by moisture when bonding a silicone rubber product or the like, and has excellent adhesiveness.

[0010]

The present inventor has conducted intensive studies to achieve the above object, and as a result, has found that R ₃ SiO
M units represented by _1/2 (where R represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms) and SiO
Solvent-soluble copolymer consisting of _4/2 Q units (a
Component) and an organopolysiloxane containing two or more ketimino groups represented by the following formula (1) in one molecule (component b):
And an organopolysiloxane (component (c)) containing two or more epoxy groups per molecule as a main component, has an initial tackiness, and is cured in a short time by moisture. The inventors have found that they show good adhesiveness, and have accomplished the present invention.

[0011]

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Accordingly, the present invention provides: (a) a solvent-soluble copolymer comprising the above-mentioned M units and Q units; (b) an organopolysiloxane containing two or more ketimino groups represented by the above formula (1) in one molecule. Provided is an adhesive composition comprising a siloxane, and (c) an organopolysiloxane containing two or more epoxy groups in one molecule.

Now, the present invention will be described in further detail. The component (a) of the present invention is a solvent-soluble copolymer composed of M units of R ₃ SiO _1/2 and Q units of SiO _4/2 .

Here, R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms. Examples of such a monovalent hydrocarbon group include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group and a hexyl group; a cycloalkyl group such as a cyclohexyl group; an alkenyl group such as a vinyl group and an allyl group; An aryl group such as a tolyl group, and a chloromethyl group, a trifluoropropyl group, a cyanoethyl group, and the like, in which some or all of the hydrogen atoms of these groups are substituted with a halogen atom, a cyano group, or the like, can be given.

The ratio M / Q between the M unit and the Q unit is preferably in the range of 0.6 to 1, and the component (a) includes RSiO _3/2 unit and R ₂ SiO _2/2 The unit is (a)
It may be contained at a ratio of 30 mol% or less in the components.

To produce the copolymer of component (a),
For example, a known method such as blending an M unit represented by R ₃ SiCl and a Q unit represented by SiCl ₄ at a desired M / Q ratio and then co-hydrolyzing and condensing can be employed. A copolymer can be obtained.

The solvent-soluble copolymer of the component (a) may contain a ketimino group represented by -R ¹ N = Z, which will be described later, in a proportion of 20 mol% or less of R in a state bonded to a silicon atom. .

The component (b) of the present invention is an organopolysiloxane containing two or more ketimino groups represented by the following formula (1) in one molecule.

[0019]

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In the above formula, R ¹ is a substituted or unsubstituted divalent hydrocarbon group having 1 to 8 carbon atoms, or 1 to 8 carbon atoms.
Is a divalent organic group containing an ether bond, an ester bond or an —NH— bond.

Examples of the substituted or unsubstituted divalent hydrocarbon group having 1 to 8 carbon atoms include the following groups. -CH
_{2 -, - CH 2 CH 2} -, - CH 2 CH 2 CH 2 -, - CH 2
_{CH 2 CH 2 CH 2 CH 2} -, - CH 2 CH 2 CH 2 CH 2 CH
_{2 CH 2 CH 2 -, -} C 6 H 4 -

Examples of the divalent organic group having 1 to 8 carbon atoms containing an ether bond, an ester bond or an -NH-bond include the following groups. _{-CH 2 CH 2 OCH 2 CH 2} C
_{H 2 -, - CH 2 CH} 2 OCH 2 CH 2 OCH 2 CH 2 -, -
_{CH 2 COOCH 2 CH 2 OCOCH 2} -, - CH 2 COO
_{CH 2 (CH 3) CHOCOCH 2} -, - CH 2 CH 2 NH
_{CH 2 CH 2 -, - CH} 2 CH 2 NHCH 2 CH 2 NHCHH
₂ CH ₂ −

Z in the above formula (1) is a group represented by the following formula.

[0024]

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Specific examples of the above Z include the following groups (wherein isoBu represents an isobutyl group).

[0026]

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The structure of the organopolysiloxane of the component (b) of the present invention is not particularly limited as long as it has two or more ketimino groups represented by the above formula (1) in one molecule. , Branched or cyclic, and the ketimino group of the formula (1) may be bonded to either the terminal or the side chain of the molecular chain. In order to obtain a rubber composition giving the following formula, a linear organopolysiloxane represented by the following formula is more preferable (in the following formula, Me is a methyl group).
Hereinafter the same).

[0028]

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In this case, R ¹ in the above formula is the same as described above, and R ⁵ and R ⁶ are each an alkyl group, alkenyl group, aryl group, cyclohexyl group having 1 to 8 carbon atoms or a carbon atom of these groups. Is a group in which part or all of the hydrogen atoms bonded to is substituted with a halogen atom, a cyano group, or the like, such as a methyl group, an ethyl group, a propyl group, a vinyl group, an allyl group, a phenyl group, a tolyl group, a cyclohexyl group, And a fluoropropyl group.

Further, m and n are each an integer of 5 or more, and the organopolysiloxane has a viscosity at 25 ° C. of 25 to 500,000 cst, particularly 1,000 to 1 cst.
It is preferable to be in the range of 00000 cst, and it is preferable to adjust m and n so that the viscosity is in this range.

Specific examples of the organopolysiloxane of the component (b) having a terminal ketimino group include the following compounds (in the following formula,
t is an ethyl group, and isoBu is an isobutyl group. Hereinafter the same).

[0032]

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As the organopolysiloxane containing a ketimino group in the side chain, the following compounds are specifically exemplified.

[0034]

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The polymerization degree of the organopolysiloxane of the component (b) is preferably in the range of 100 to 20,000, but in order to make the adhesive strength practical, the polymerization degree must be 3,000 or more. Preferably, the degree of polymerization is not more than 10,000 in consideration of workability.

The organopolysiloxane having a ketimino group of the formula (1) according to the present invention can be prepared by adding a ketone compound to an organopolysiloxane having an amino group, heating and reacting the resulting organopolysiloxane to the outside of the system. By removing it, it can be easily manufactured.

In this case, examples of the organopolysiloxane containing an amino group include the following.

[0038]

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Examples of the ketone compound include acetone, methyl ethyl ketone, methyl isobutyl ketone,
Cyclohexanone, cyclopentanone, cyclooctanone and the like are preferably used.

When the ketone compound is added to the above-mentioned amino group-containing organopolysiloxane, it is required to be added in an amount of not less than 1 mole, especially not less than 1 mole, per mole of amino group in the organopolysiloxane.
It is preferable to add at a ratio of 〜2 mol.

Further, the above reaction is desirably carried out in the presence of an organic solvent such as toluene, and the reaction conditions can be adjusted as appropriate. It is preferable to react for 1 to 3 hours while removing.

The components (a) and (b) are
It is preferable to use the composition in a weight ratio of 30:70 to 70:30 from the viewpoint of adhesive strength.

Next, as the organopolysiloxane having two or more epoxy groups in one molecule, which is the component (c) of the present invention, those represented by the following general formula (2) are preferably used.

[0044]

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Wherein E is a glycidoxypropyl group, a glycidoxymethyl group or a 3,4-epoxycyclohexylethyl group, and R ⁷ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms. (Eg, a methyl group, an ethyl group, a butyl group, a phenyl group, etc.), and X is a silanol group or a hydrolyzable group (eg, a methoxy group, an ethoxy group, etc.). A is 0.1 to 1, b is 0 to 2, c is 0 to 2, a
+ B + c is a number in the range of 0.1 ≦ a + b + c <4.

Further, the organopolysiloxane of the above formula (2) may be linear, branched or cyclic, and the position of the epoxy group may be either in the molecule or at the terminal.

Specific examples of the organopolysiloxane containing two or more epoxy groups in one molecule include the following compounds.

[0048]

Embedded image (E in the above formula is the same as above, n is an integer of 2 or more,
m is an integer of 0 or more. )

In the present invention, the amounts of the components (b) and (c) used are determined by the amount of the ketimino group contained in the component (b).
Component (a) also contains ketimino groups (total amount) The mole number of epoxy groups contained in component (c) per mole is from 0.5 to 10 moles, especially from 1 to 5 moles. It is desirable to set such a ratio. When the above molar ratio is 0.5
If the amount is less than 10 moles or more than 10 moles, tackiness may remain after curing, leaving a tacky feeling on the surface.

A catalyst may be added to the adhesive composition of the present invention, if necessary, in addition to the above essential components, in order to promote curing. Specific examples of the catalyst include tin carboxylate salts such as tin naphthenate, tin caprylate, and tin oleate, dibutyltin diacetate, dibutyltin octate, dibutyltin dilaurate, dibutyltin dioleate, and the like. Tin compounds such as diphenyltin diacetate, dibutyltin oxide, sibutyltin dimethoxide, dibutylbis (triethoxysiloxy) tin, dibutyltin benzyl maleate, tetraethoxytitanium, tetraisopropoxytitanium, tetra-n
-Titanium esters such as butoxytitanium, tetrakis (2-ethylhexoxy) titanium, dipropoxybis (acetylacetona) titanium and titanium isopropoxyoctylene glycol, and titanium chelate compounds.

The composition of the present invention is, for example, 50 ° C. to 150 ° C.
There is no particular need to add a catalyst when curing by heating to about ° C, but it is preferable to add a catalyst for curing at room temperature. The amount of catalyst added is
(A), (b), (c) 0.01 to 5 parts, preferably 0.1 to 5 parts by weight based on 100 parts (total parts by weight)
When the amount is less than 0.01 part, the catalytic effect is poor, and the curing takes too long, which may not be practical. When the amount exceeds 5 parts, the curing is too fast or uncured. May cause poor preservability when stored for a long time, or may be economically disadvantageous.

Further, in addition to the above catalyst, a basic compound may be used in combination to enhance the catalytic activity. Examples of the basic compound include amines such as octylamine and laurylamine, imidazoline, tetrahydropyrimidine and the like. Cyclic amidine, 1,8-diaza-bicyclo (5.
4.0) Super bases such as undecene-7 (DBU) and guanidine, tetramethylguanidylpropyltrimethoxysilane, tetramethylguanidylpropyldimethoxysilane, tetramethylguanidylpropyltris (totimethylsiloxy) silane Guanidyl group-containing silane such as
Further, a partial hydrolyzate thereof, a guanidyl group-containing siloxane, or the like is used. The basic compound is preferably added in an amount of 0.1 to 1 part based on 100 parts of the total of the components (a), (b) and (c).

A filler may be added to the composition of the present invention for the purpose of reinforcing or increasing the amount or imparting thixotropic properties. Here, known fillers are used, for example, fumed silica, calcined silica, precipitated silica, crushed silica, finely divided silica such as fused silica powder, diatomaceous earth, iron oxide, zinc oxide, titanium oxide, barium oxide. Metal oxides such as magnesium and magnesium oxide, metal carbonates such as calcium carbonate, magnesium carbonate and zinc carbonate, metal hydroxides such as cerium hydroxide and aluminum hydroxide, glass fibers, glass wool, carbon black and fine powder Examples thereof include mica, asbestos, spherical silica, spherical sesquioxane powder, and powders obtained by hydrophobizing the surface with silane or the like.

Among these fillers, carbon black is particularly preferably used as one which prevents sagging on a vertical surface and does not impair the initial tackiness. As the carbon black, those usually blended in a silicone rubber composition can be used. Specifically, acetylene black, conductive furnace black (C
F), Super Conductive Furnace Black (SC
F), Extra Conductive Furnace Black (X
CF), conductive channel black (CC), furnace black or channel black heat-treated at a high temperature of about 1500 ° C., and the like. .

Specific examples of acetylene black include electrified acetylene black (manufactured by Denki Kagaku), Shaunigan acetylene black (manufactured by Shaunigan Chemical), and specific examples of conductive furnace black include Continex CF (manufactured by Continental Carbon). Vulcan CF
As specific examples of (Cabot) and Super Conductive Furnace Black, Asahi HS-500 (Asahi Carbon) as specific examples of Continex SCF (Continental Carbon), Vulcan SC (Cabot), and Extra Conductive Furnace Black , Vulcan XC-72 (manufactured by Cabot), and Colux L (manufactured by Degussa) as a conductive channel black. In addition, Ketjen Black EC and Ketjen Black EC-60, which are one kind of furnace black, are used.
0JD (made by Ketjen Blackshi International)
Can also be used.

As for the type of carbon, it is preferable to use conductive carbon when conductivity is required.
Particularly preferred carbon blacks for the present invention include furnace black, Ketjen black, channel black, acetylene black and the like.

The filler may be added in such an amount that the adhesive strength is not impaired. Usually, (a), (b), (c)
It can range from 1 to 10 parts per 100 parts of the total amount of the components.

Further, the composition of the present invention may optionally contain other optional components such as a thixotropic agent such as polyethylene glycol or a derivative thereof, a pigment, a dye, an antioxidant, an antioxidant and an antistatic agent. Flame retardants such as antimony oxide, antimony oxide, and paraffin chloride; thermal conductivity improvers such as boron nitride and aluminum oxide; organic silicon compounds having reactive organic groups such as amino groups, epoxy groups, and mercapto groups as adhesion promoters, so-called Conventionally known various additives such as a silane coupling agent, a plasticizer, an anti-sagging agent, an antifouling agent, an antiseptic, a bactericide and an antifungal agent may be added.

The composition of the present invention is preferably prepared from toluene, xylene,
It may be diluted with a hydrocarbon solvent such as petroleum ether or a solvent such as ketones or esters. The use amount of these solvents is not particularly limited, but is usually used in the range of 5 to 50% by weight from the viewpoint of ease of operation.

[0060]

The adhesive composition of the present invention has an initial tackiness, can be bonded in a short time by moisture when bonding a silicone rubber product or the like, and is excellent in adhesiveness. is there.

[0061]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. All parts in each example are parts by weight.

[Examples 1 and 2, Comparative Example] Consists of 98.975% by mole of dimethylsiloxane unit and 1.0% by mole of methyl γ-aminopropylsiloxane unit, and the molecular chain end is blocked with a dimethyl γ-aminopropylsilyl group. 25
100 parts of an organopolysiloxane having a viscosity of 8,000,000 cs at 50 ° C. was dissolved by adding 50 parts of toluene, and 150 parts of a solvent-soluble silicone resin polymer and 5 parts of methyl isobutyl ketone were added thereto. The mixture was heated for 2 hours while removing water to remove 0.25 g of generated water, and the reaction was completed. The obtained liquid had a viscosity of 25,000 cs at 25 ° C. and a uniform liquid (L) having a non-volatile content of 69.3%.

This liquid contained an organopolysiloxane having a ketimino group represented by the following formula and the solvent-soluble resin polymer.

[0064]

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To 100 parts of the obtained liquid (L), 5 parts of acetylene black (manufactured by Denki Kagaku Co., Ltd.) was added, and the mixture was uniformly mixed with a three-roll mill. A rubber composition was manufactured.

Next, the above silicone rubber composition was uniformly applied to a thickness of 0.5 mm on an aluminum test panel having a length of 50 mm, a width of 25 mm and a thickness of 2 mm, and left at room temperature for 15 minutes. A silicone rubber sheet molded and vulcanized to 2 mm was pressure-bonded at a pressure of about 1 kgf / cm ² to prepare a test body as shown in FIG. 1, and a change with time of the adhesive force was measured. In FIG. 1, 1 is an aluminum test panel, 2 is a silicone rubber composition,
3 is a silicone rubber sheet.

[0067]

[Table 1]

[Brief description of the drawings]

FIG. 1 is an explanatory view of the measurement of the adhesive force of the silicone rubber composition of the present invention.

[Description of Signs] 1 Aluminum test panel 2 Silicone composition 3 Silicone rubber sheet

Claims (1)

(57) [Claims] 1. A _(a) R _{3 SiO 1/2} units (Here, R
Represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms) and a SiO _4/2 unit, (b) represented by the following formula (1) in one molecule: An organopolysiloxane containing two or more ketimino groups, -R ¹ N = Z (1) wherein R ¹ is a substituted or unsubstituted divalent hydrocarbon group having 1 to 8 carbon atoms; Or an ether bond having 1 to 8 carbon atoms,
An ester bond or -NH- bond A substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R
⁴ is a substituted or unsubstituted divalent hydrocarbon group having 1 to 8 carbon atoms. ). (C) An adhesive composition comprising an organopolysiloxane containing two or more epoxy groups in one molecule.