JPH05345859A - Curable composition - Google Patents

Abstract

PURPOSE:To obtain a curable composition, excellent in high hardness, elongation, tensile strength, heat resistance and adhesion and useful for bonding and fixing, etc., electrical and electronic parts, etc., by blending a specific ketimino group- containing organopolysiloxane with a specified epoxy group-containing organopolysiloxane. CONSTITUTION:This curable composition is obtained by blending (A) an organopolysiloxane, containing two or more ketimino groups expressed by the formula [R<1> is 1-8C (substituted)bivalent hydrocarbon, 1-8C bivalent organic group containing ether bond, ester bond or NH bond; Z is CR<2>R<3> (R<2> and R<3> are 1-8C monovalent hydrocarbon), etc.] in one molecule with (B) an organopolysiloxane containing two or more epoxy groups in one molecule. Furthermore, the components (A) and (B) are preferably used in amounts so as to provide the number of mol of the epoxy groups in the component (B) within the range of 1-5 mol based on 1 mol ketimino group in the component (A).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to applications such as adhesive fixing of electric / electronic parts, coating, potting, sealant and adhesive for construction, seal and adhesive of automobile engine parts. It relates to a suitable curable composition.

[0002]

BACKGROUND OF THE INVENTION Silicone rubber is widely used in the electric / electronic industry, the construction industry, the automobile industry, the office machine-related industry, etc. because of its characteristics such as heat resistance and weather resistance. Has been done.

However, among various silicone rubbers, the condensation type room temperature curable composition is generally put into practical use as a sealant or the like, but since it cures due to moisture, it cures slowly at room temperature, and thus it cures. It is necessary to use a larger amount of curing catalyst than usual for the purpose of accelerating curing, and therefore storage stability when uncured is poor, and physical properties of rubber after curing and its heat resistance, weather resistance, water resistance, adhesiveness, etc. There was a problem such as bad.

Further, a silicone rubber composition obtained by hydrosilylating an alkenyl group-containing organopolysiloxane and a SiH group-containing organopolysiloxane with a platinum catalyst is used as a potting agent or an adhesive agent for electric and electronic parts. However, since this composition uses a platinum compound as a catalyst, a sulfur compound,
There is a problem that the catalyst may be poisoned by a nitrogen compound, a phosphorus compound, etc. and may not be cured depending on the method of use.

Therefore, it has been desired to improve the above problems in the silicone rubber type 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 rapidly to give a cured silicone rubber excellent in various physical properties and which is good in terms of safety.

[0007]

Means for Solving the Problems and Actions The inventors of the present invention have conducted extensive studies in order to achieve the above-mentioned object, and as a result, an organopoly compound containing two or more ketimino groups represented by the following formula (1) in one molecule. A curable composition containing siloxane (a component) and an organopolysiloxane (b component) containing two or more epoxy groups in one molecule as main components is a tin compound or a titanium compound as a curing catalyst even at room temperature. Addition of the usual amount of the above causes rapid curing, and when heated, it cures in a short time even without a catalyst. Therefore, the storage stability when uncured is good, and there is no problem of poisoning by the catalyst. The present inventors have found that the curing gives a silicone rubber cured product having high hardness and excellent various physical properties such as elongation and tensile strength, and thus has accomplished the present invention.

[0008]

[Chemical 2]

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

The present invention will be described in more detail below. 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]

[Chemical 3]

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 a -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 an ether bond, an ester bond or a -NH- bond having 1 to 8 carbon atoms 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]

[Chemical 4]

Specific examples of Z are as follows (in the formula, isoBu represents an isobutyl group).

[0018]

[Chemical 5]

The organopolysiloxane of the component (a) of the present invention is not particularly limited in its structure as long as it has two or more ketimino groups represented by the above formula (1) in one molecule, and the structure is linear. , 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, but a cured product showing rubber elasticity after curing In order to obtain a curable rubber composition that gives the following formula, a linear organopolysiloxane represented by the following formula is more preferable (in the following formula, Me is a methyl group, and the same applies hereinafter).

[0020]

[Chemical 6]

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

Further, m and n are each an integer of 5 or more, and the above organopolysiloxane has a viscosity at 25 ° C. of 25 to 500,000 cst, particularly 1,000 to 1.
It is preferably in the range of 0,000 cst, and m and n are preferably adjusted 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 in the following formula:
t is an ethyl group and isoBu is an isobutyl group. The same applies below).

[0024]

[Chemical 7]

Specific examples of the organopolysiloxane having a ketimino group in its side chain include the following compounds.

[0026]

[Chemical 8]

The organopolysiloxane containing a ketimino group of the formula (1) according to the present invention is prepared, for example, by adding a ketone compound to an organopolysiloxane containing an amino group and heating and reacting the resulting organopolysiloxane with water generated outside the system. It can be easily manufactured by removing.

In this case, examples of the amino group-containing organopolysiloxane are as follows.

[0029]

[Chemical 9]

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, 1 mol or more, especially 1 mol, per 1 mol of amino groups in the organopolysiloxane are added.
It is preferable to add it in 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 appropriately adjusted. However, by heating from 50 ° C. to 150 ° C., the produced water is removed from the system. It is preferable to react for 1 to 3 hours while removing.

Next, as the organopolysiloxane having 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]

[Chemical 10]

Here, 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.). Also, 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 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.

[0038]

[Chemical 11] (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 component (a) and the component (b) used are such that the mole number of the epoxy group contained in the component (b) is 0.5 per mol of the ketimino group contained in the component (a).
It is desirable that the proportion be in the range of 10 to 10 mol, particularly 1 to 5 mol. If the 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.

In addition to the above-mentioned essential components, a catalyst may be added to the curable composition of the present invention, if necessary, to accelerate the curing. Specific examples of the catalyst include tin carboxylates such as tin naphthenate, tin caprylate and tin oleate, dibutyltin diacetate, dibutyltin octate, dibutyltin dilaurate, dibutyltin dioleate, Tin compounds such as diphenyltin diacetate, dibutyltin oxide, cibutyltin dimethoxide, dibutylbis (triethoxysiloxy) tin, dibutyltin benzyl maleate, tetraethoxy titanium, tetraisopropoxy titanium, tetra-n
Examples include titanic acid esters such as butoxytitanium, tetrakis (2-ethylhexoxy) titanium, dipropoxybis (acetylacetona) titanium, titanium isopropoxyoctyleneglycol, and titanium chelate compounds.

The composition of the present invention is, for example, 50 ° C to 150 ° C.
It is not particularly necessary to add a catalyst when the composition is heated to about 0 ° C. for curing, but it is preferable to add a catalyst for curing at room temperature. In case of room temperature curing, the amount of catalyst added is
For 100 parts of component (a) (parts by weight, the same applies hereinafter), 0.
It is preferably in the range of 01 to 5 parts, particularly 0.1 to 2 parts. When it is less than 0.01 parts, the catalytic effect is poor and curing may take too long to be practical, and more than 5 parts. In some cases, the curing may be too fast, the storage stability may be poor when the uncured product is stored for a long period of time, or it may be economically disadvantageous.

Further, in addition to the above-mentioned catalyst, a basic compound may be used in combination for enhancing the catalytic activity. Examples of the basic compound include amines such as octylamine and laurylamine, imidazoline, tetrahydropyrimidine and the like. The cyclic amidine of 1,8-diaza-bicyclo (5.
4.0) Ultra strong base such as undecene-7 (DBU) and guanidine, tetramethylguanidylpropyltrimethoxysilane, tetramethylguanidylpropyldimethoxysilane, tetramethylguanidylpropyltris (totimethylsiloxy) silane Silane containing guanidyl group, such as
Further, its partial hydrolyzate and guanidyl group-containing siloxane are 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 preferably 1 to 1 part.

A filler may be added to the composition of the present invention for the purpose of reinforcing or increasing the amount. Known fillers are used here, for example, fumed silica,
Fine silica such as calcined silica, precipitated silica, crushed silica, fused silica powder, diatomaceous earth, iron oxide, zinc oxide, titanium oxide, barium oxide, metal oxides such as 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, finely powdered mica, asbestos, spherical silica, spherical sesquioxane powder and their surfaces with silane, etc. Those that have been hydrophobized may be mentioned.

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

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

The composition of the present invention is, for example, toluene, xylene, from the viewpoint of convenience in use when it is applied to a substrate.
It may be diluted with a hydrocarbon solvent such as petroleum ether, or a solvent such as ketones or esters.

The curable composition of the present invention cures rapidly in about 1 to 3 days when left at room temperature, but 50 to 150
When heated to ℃, it hardens in less than 1 to 3 hours,
It gives a cured rubber product with excellent physical properties.

[0048]

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

[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 a nitrogen gas atmosphere. About 3
After reacting for a time, the temperature was raised to 170 ° C. and maintained at that temperature for about 30 minutes to deactivate the catalyst.

[0052]

[Chemical formula 12]

The colorless transparent liquid thus obtained was analyzed by gel chromatography and an infrared spectrometer. As a result, the viscosity at 25 ° C. represented by the following formula was 30,000 cp and the refractive index was 1.4.
It was No. 01 aminoorganopolysiloxane.

[0054]

[Chemical 13]

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

The colorless and transparent liquid thus obtained was analyzed by gel chromatography and an 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.
No. 02 organopolysiloxane (polymer
A).

[0057]

[Chemical 14]

[Synthesis Examples 2 and 3] The following compounds were produced in the same manner as in Synthesis Example 1 and reacted with methyl isobutyl ketone to obtain an organopolysiloxane (polymer B, polymer C) represented by the following formula. It was

[0059]

[Chemical 15]

[0060]

[Chemical 16]

[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 a curable composition.

These curable compositions were molded into a sheet having a thickness of 2 mm and allowed to stand for 7 days under the conditions of 20 ° C. and 55% humidity, and then various physical properties were measured according to JISK-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 rapidly cured to give a rubber cured product having excellent physical properties.

Claims (1)

[Claims] 1. (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.