JP2643725B2 - Curable composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for adhesives and fixing of electric and electronic parts, coating and potting, seals and adhesives for construction, and seals and adhesives for automobile engine parts. It relates to a suitable curable composition.

[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.

[0003] However, among various silicone rubbers, condensation-type room temperature curable compositions are generally put into practical use as sealants and the like. It is necessary to use a larger amount of curing catalyst than usual for the purpose of accelerating the curing, and therefore, the storage stability when uncured is poor, the rubber physical properties after curing and its heat resistance, weather resistance, water resistance, adhesion, etc. There were problems such as bad.

Further, a silicone rubber composition obtained by subjecting an alkenyl group-containing organopolysiloxane and an SiH group-containing organopolysiloxane to a hydrosilylation reaction with a platinum-based catalyst is used as a potting agent or adhesive for electric or electronic parts. However, since this composition uses a platinum compound as a catalyst, a sulfur compound,
There is a problem that the catalyst is poisoned by a nitrogen compound, a phosphorus compound, and the like, and there is also a problem that it does not cure depending on the method of use.

Accordingly, it has been desired to improve the above-mentioned problems in a silicone rubber-based curable composition.

The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a curable composition which cures quickly to give a cured product of silicone rubber excellent in various physical properties, and also has good safety.

[0007]

The present inventors have made intensive studies to achieve the above object, and as a result, have found that an organopolysiloxane containing two or more ketimino groups represented by the following formula (1) in one molecule: A curable composition containing a siloxane (a component) and an organopolysiloxane (b component) containing two or more epoxy groups in one molecule as a main component is a tin compound or a titanium compound as a curing catalyst even at room temperature. Curing quickly by adding a normal amount, etc., and curing in a short time even without heating when heated, therefore, good storage stability when uncured, and no problem of poisoning by the catalyst, and The present inventors have found that a silicone rubber cured product having high hardness and excellent physical properties such as elongation and tensile strength is obtained by curing, and the present invention has been accomplished.

[0008]

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Therefore, the present invention provides: (a) an organopolysiloxane containing two or more ketimino groups represented by the above formula (1) in one molecule; and (b) two or more epoxy groups in one molecule. A curable composition containing an organopolysiloxane is provided.

Now, the present invention will be described in further detail. The component (a) of the present invention is an organopolysiloxane containing two or more ketimino groups represented by the following formula (1) in one molecule.

[0011]

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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.

[0016]

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

[0018]

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The structure of the organopolysiloxane (a) 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 curable 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; the same applies hereinafter).

[0020]

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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. And a fluoropropyl group.

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 above-mentioned component (a) having a ketimino group at the terminal include the following compounds (E:
t is an ethyl group, and isoBu is an isobutyl group. Hereinafter the same).

[0024]

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

[0026]

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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.

[0029]

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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 a 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 more 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.

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

[0034]

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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. (For example, a methyl group, an ethyl group, a butyl group, a phenyl group, etc.), and X is a silanol group or a hydrolyzable group (for example, 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 value in the range.

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 having two or more epoxy groups in one molecule include the following compounds.

[0038]

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 amount of component (a) and component (b) used is such that the number of moles of epoxy group contained in component (b) is 0.5 per mole of ketimino group contained in component (a).
It is desirable that the ratio be in the range of 10 to 10 mol, particularly 1 to 5 mol. If the above molar ratio is less than 0.5 mol or more than 10 mol, tackiness may remain after curing and tackiness may remain on the surface.

A catalyst may be added to the curable composition of the present invention, if necessary, in order to promote curing, in addition to the above essential components. 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) 100 parts by weight of component (parts by weight, the same applies hereinafter).
The content is preferably in the range of from 01 to 5 parts, particularly from 0.1 to 2 parts. If the amount is less than 0.01 part, the catalytic effect is poor, and it takes too much time for curing, which may not be practical. Curing may be too fast, the storage stability when stored in an uncured state for a long period of time may be poor, or it 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 amount of the basic compound added is 0.0 with respect to 100 parts of the total amount of the components (a) and (b).
It is preferable that the content be 1 to 1 part.

A filler may be added to the composition of the present invention for the purpose of reinforcing or increasing the weight. Here, known fillers are used, for example, fumed silica,
Fine powdered silica such as calcined silica, precipitated silica, pulverized silica, fused silica powder, diatomaceous earth, iron oxide, zinc oxide, titanium oxide, metal oxides such as barium oxide, magnesium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, etc. Metal carbonates, metal hydroxides such as cerium hydroxide and aluminum hydroxide, glass fibers, glass wool, carbon black, fine mica, asbestos, spherical silica, spherical sesquioxane powder and their surfaces with silane, etc. Examples include those subjected to a hydrophobic treatment.

The amount of the filler is not particularly limited, but is 1 to 100 parts of the total of the components (a) and (b).
It is preferable to use it in the range of 200 parts.

The composition of the present invention may further contain, as necessary, other thixotropy-imparting agents such as polyethylene glycol or a derivative thereof, pigments, dyes, antioxidants, antioxidants, and antistatic agents. 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, for example, toluene, xylene,
It may be diluted with a hydrocarbon solvent such as petroleum ether or a solvent such as ketones or esters.

When the curable composition of the present invention is left at room temperature, it cures quickly in about 1 to 3 days.
When heated to ℃, it cures in less than 1-3 hours,
Provides a cured rubber material with excellent physical properties.

[0048]

The curable composition of the present invention cures quickly to give a rubber cured product having high hardness, excellent elongation and tensile strength, and is also excellent in safety. Therefore, the composition of the present invention can be used for adhesive fixing of electric / electronic parts, coating, potting and the like, or for architectural sealing.
It can be suitably used for applications such as runts and adhesives, and seals and adhesives for automobile engine parts.

[0049]

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.

First, a synthesis example of the organopolysiloxane used in the present invention will be described.

[Synthesis Example 1] 2.48 g of a compound represented by the following formula, 444 g of octamethyltetrasiloxane, and 300 ppm of TBPH (tetrabutylphosphonium hydroxide) were added to a 1-liter flask.
The reaction was carried out by heating to 120 ° C. under nitrogen gas flow. About 3
After reacting for hours, the temperature was raised to 170 ° C. and maintained at that temperature for about 30 minutes to deactivate the catalyst.

[0052]

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When the obtained colorless and transparent liquid was analyzed by gel chromatography or infrared spectrometer, the viscosity at 25 ° C. represented by the following formula was 30,000 cp and the refractive index was 1.4.
No. 01 aminoorganopolysiloxane.

[0054]

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Next, 50 g of methyl isobutyl ketone and 200 g of toluene were added to 400 g of the aminoorganopolysiloxane, and the mixture was heated to the reflux temperature of toluene and reacted for 3 hours while removing generated water out of the system. And methyl isobutyl ketone were removed under reduced pressure.

When the obtained colorless and transparent liquid was analyzed by gel chromatography and infrared spectrometer, it was represented by the following formula, and had a viscosity at 25 ° C. of 31,000 cp and a refractive index of 1.4.
02 organopolysiloxane (polymer
A).

[0057]

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[Synthesis Examples 2 and 3] The following compounds were prepared in the same manner as in Synthesis Example 1 and reacted with methyl isobutyl ketone to obtain organopolysiloxanes (polymer B and polymer C) represented by the following formulas. Was.

[0059]

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[0060]

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[Examples 1, 2, 3] Using the organopolysiloxanes (polymers A, B, C) obtained in the above synthesis examples, the components shown in Table 1 were mixed to obtain curable compositions.

Each of these curable compositions was formed into a sheet having a thickness of 2 mm, left for 7 days at a temperature of 20 ° C. and a humidity of 55%, and various physical properties were measured in accordance with JIS K-6301. The results are also shown in Table 1.

[0063]

[Table 1]

From the results shown in Table 1, it was confirmed that the curable composition of the present invention was quickly cured to give a cured rubber having excellent physical properties.

Claims (1)

(57) [Claims] (A) an organopolysiloxane containing two or more ketimino groups represented by the following formula (1) in one molecule: (B) A curable composition comprising an organopolysiloxane containing two or more epoxy groups in one molecule.