JP4766679B2 - Heat-curing organopolysiloxane composition - Google Patents

Description

  The present invention relates to a novel thermosetting organopolysiloxane composition.

Conventionally, various curable silicone rubber compositions that give rubber-like elastic bodies at room temperature or by heating are known. Silicone rubber is used in various fields because it has excellent weather resistance, durability, heat resistance, cold resistance, electrical characteristics, and the like compared to other organic rubbers.
The basic composition of the room temperature curable silicone rubber contains a base polymer having a hydrolyzable group, a silane compound having a hydrolyzable group, and, if necessary, an organic tin or organic titanium compound as a curing catalyst. Room temperature curable silicone rubber cures by reacting with moisture in the air, so that it does not require a special device and is widely used as a sealing material for construction, an adhesive seal material for electrical and electronic use, and the like. However, this type of rubber has a long curing time and is not suitable for mass production.

  On the other hand, the basic composition of heat-curable silicone rubber includes a base polymer (organopolysiloxane) having an alkenyl group, a silane or siloxane compound having a Si-H group, and a platinum catalyst or a rhodium catalyst as a curing catalyst. It is general (see, for example, Patent Documents 1 and 2).

JP 2005-89681 A JP 2005-175119 A

However, in the case of the thermosetting silicone rubber described in Patent Documents 1 and 2, the curing time can be shortened by heating, but there is a problem that it is susceptible to curing inhibition by sulfur, amine, etc., and the usage environment is limited. . Platinum catalysts and rhodium catalysts are expensive and disadvantageous economically.
Accordingly, an object of the present invention is to provide an inexpensive thermosetting organopolysiloxane composition that is excellent in curability even in the presence of sulfur or amine.

In order to achieve the above-mentioned object, the present inventors have replaced a conventional base polymer with a diorganopolysiloxane having a hydrolyzable group and a specific metal complex, thereby inhibiting the curing of sulfur, amine and the like. It has been found that a thermosetting organopolysiloxane composition which is not easily received and does not require a platinum catalyst can be obtained.
That is, in order to achieve the above object, the heat-curing organopolysiloxane compositions of the present invention, at least two organic and within each molecule (A) a hydroxyl and / or hydrolyzable groups bonded to silicon atoms , A diorganopolysiloxane having a viscosity of 20 to 1,000,000 mPa · s at 25 ° C. , and 0.01 to 20 parts by mass with respect to 100 parts by mass of the component (B) (A), and a group of zinc, copper and iron And an acetylacetonate complex of a metal selected from the group consisting of

The (A) diorganopolysiloxane has the following general formula (1)
(In the formula, R is an independent unsubstituted or monovalent hydrocarbon group substituted with a halogen atom and / or a cyano group, U is an independent oxygen atom or a divalent hydrocarbon group having 1 to 8 carbon atoms, Y Are independent hydroxyl groups or hydrolyzable groups, m is an integer of 0 to 2, and n is a natural number such that the viscosity of the obtained diorganopolysiloxane at 25 ° C. is 20 to 1,000,000 mPa · s). It is preferably represented.

(C) It is preferable to further contain 1 to 50 parts by mass of hydrophilic silica and / or hydrophobic silica having a BET specific surface area of 10 m ² / g or more as a filler with respect to 100 parts by mass of component (A) .
The heat curing temperature is preferably 60 ° C. or higher.

  According to the present invention, an inexpensive thermosetting organopolysiloxane composition which is not easily inhibited by sulfur and amines and does not require a platinum catalyst can be obtained.

  Hereinafter, the thermosetting organopolysiloxane composition according to the embodiment of the present invention will be described. The heat-curable organopolysiloxane composition of the present invention contains the following components (A) and (B) as essential components.

[(A) component]
The component (A) is a main component (base polymer) of the organopolysiloxane composition of the present invention, is a condensation-curing room temperature curing type, and one molecule of silicon atom to which a hydroxyl group and / or a hydrolyzable group is bonded. It is a diorganopolysiloxane having at least two therein.
In the component (A), the hydroxyl group and / or hydrolyzable group bonded to the silicon atom is crosslinked and cured during the reaction. In the component (A), the reason why the number of silicon atoms in the molecule is 2 or more is that if the number of silicon atoms is less than 2, a good rubber elastic body cannot be obtained as a composition.
The conventionally used platinum catalyst serves as a catalyst for the addition reaction between the alkenyl group-containing siloxane and the hydrosilyl group-containing siloxane. However, in the case of the component (A), the addition reaction does not occur. Is not used.

As the component (A), the following general formula (1)
Wherein R is an independent unsubstituted or substituted monovalent hydrocarbon group, U is an independent oxygen atom or divalent hydrocarbon group having 1 to 8 carbon atoms, and Y is an independent hydroxyl group or hydrolysis. M is an integer of 0 to 2, and n is a natural number such that the viscosity of the obtained diorganopolysiloxane at 25 ° C. is 20 to 1,000,000 mPa · s). It is preferable to use a diorganopolysiloxane in which the chain end is blocked with a hydroxyl group and / or a hydrolyzable group.

R is an alkyl group such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, octadecyl; cycloalkyl such as cyclopentyl, cyclohexyl, etc. Groups: vinyl groups, allyl groups, butenyl groups, pentenyl groups, hexenyl groups and other alkenyl groups; phenyl groups, tolyl groups, xylyl groups, aryl groups such as A- and B-naphthyl groups; benzyl groups and 2-phenylethyl groups An aralkyl group such as 3-phenylpropyl group; a group in which part or all of the hydrogen atoms of these groups are substituted with a halogen atom such as F, Cl, Br and / or a cyano group (for example, 3-chloropropyl Group, 3,3,3-trifluoropropyl group, 2-cyanoethyl group). Among these, a methyl group, a vinyl group, and a phenyl group are preferable, and a methyl group is particularly preferable.
In addition, each R in Formula (1) may be the same group, and may be different types of groups. This is expressed as “independent”.

  Examples of U include, for example, oxygen atom; alkylene group such as methylene group, ethylene group, propylene group, methylethylene group, butylene group, hexamethylene group; cycloalkylene group such as cyclohexylene group; phenylene group, tolylene group, A divalent hydrocarbon group selected from: an arylene group such as a xylylene group; a group in which some of the hydrogen atoms of these groups are substituted with a halogen atom; and a group in which the alkylene group and the arylene group are combined. An oxygen atom and / or an ethylene group are preferred.

  When Y is a hydrolyzable group, examples of the hydrolyzable group include an alkoxy group such as a methoxy group, an ethoxy group, and a propoxy group; an alkoxyalkoxy group such as a methoxyethoxy group, an ethoxyethoxy group, and a methoxypropoxy group; Groups, octanoyloxy groups, benzoyloxy groups and other acyloxy groups; vinyloxy groups, isopropenyloxy groups, 1-ethyl-2-methylvinyloxy groups and other alkenyloxy groups; dimethyl ketoxime groups, methyl ethyl ketoxime groups, diethyl keto groups Ketooxime groups such as oxime groups; amino groups such as dimethylamino groups, diethylamino groups, butylamino groups, and cyclohexylamino groups; aminoxy groups such as dimethylaminoxy groups and diethylaminoxy groups; N-methylacetamido groups, N-ethylacetamido groups , N Amide group such as a methyl benzamide group; and the like. Among these, an alkoxy group is preferable.

  m is an integer of 0 to 2, but when Y is a hydroxyl group, m is preferably 2, and when Y is a hydrolyzable group, m is preferably 0 or 1.

n is a natural number such that the viscosity of the obtained diorganopolysiloxane (component (A)) at 25 ° C. is 20 to 1,000,000 mPa · s. Preferably, n is determined so that the viscosity of component (A) at 25 ° C. is 100 to 500,000 mPa · s, more preferably 1,000 to 50,000 mPa · s.
When the viscosity at 25 ° C. of the component (A) is less than 20 mPa · s, it may be difficult to obtain a coating film having excellent physical and mechanical strength. 1,000,000 mPa · s (25 ° C. ) Exceeds the viscosity, the workability during use may be deteriorated.
In the present invention, the viscosity is a value at 25 ° C. measured with a rotational viscometer.

Specific examples of the component (A) include the following.
(In the above formulas (3) to (6), R, Y and n are the same as in the above formula (1), and m ′ is 0 or 1.)
Formula (3)-(6) can be used individually by 1 type or in combination of 2 or more types.

[Component (B)]
The metal complex as the component (B) is an essential component for curing the component (A), and is composed of a metal complex selected from the group consisting of zinc, copper, iron, and zirconium.
Specific examples of the component (B) include, for example, acetylacetonate copper (II), trifluoroacetylacetonate copper (II), acetylacetonate iron (III), trifluoroacetylacetonate iron (III), and acetylacetate. Nato zinc (II) hydrate, hexafluoroacetylacetonate zinc (II) dihydrate, zinc dibutyldithiocarbamate (II), acetylacetonate zirconium (IV), hexafluoroacetylacetonate zirconium, etc. These can be used alone or in combination of two or more.
The blending amount of the component (B) is not particularly limited and may be an amount that effectively acts as a catalyst, but is usually preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the component (A), particularly It is preferable that it is 0.1-10 mass parts. If the blending ratio of the component (B) is less than 0.01 parts by mass, the resulting composition may have insufficient curability, and if it exceeds 20 parts by mass, the resulting composition has storage stability. May decrease.

[Other ingredients]
[Component (C)]
Further, in the heat-curable organopolysiloxane composition of the present invention, a filler may be used as the component (C) for the purpose of reinforcing or increasing the amount. Examples of such a filler include hydrophilic silica such as fumed silica and precipitated silica, silica, quartz obtained by hydrophobizing these silica surfaces with hexamethyldisilazane, cyclic dimethylsiloxane, dimethyldichlorosilane, and the like. Diatomaceous earth, titanium oxide, aluminum oxide, lead oxide, iron oxide, carbon black, bentonite, graphite, calcium carbonate, mica, clay, glass beads, glass microballoon, shirasu balloon, glass fiber, polyvinyl chloride beads, polystyrene beads And acrylic beads. Among these, BET specific surface area of 10 m ² / g or more, it is preferable to use a hydrophilic silica and / or hydrophobic silica is particularly 50 to 500 m ² / g.
If the BET specific surface area is less than 10 m ² / g, sufficient rubber strength may not be obtained.

  (C) Although the compounding quantity of a component is not restrict | limited in particular, Usually, it is preferable that it is 1-50 mass parts with respect to 100 mass parts of (A) component, and it is especially 5-30 mass parts. preferable. If the content of the component (C) is less than 5 parts by mass, the physical properties of the rubber after curing may be reduced. If the content exceeds 30 parts by mass, the viscosity of the composition becomes too high, and work during mixing and construction May be worse.

[(D) component]
In order to further improve the crosslinking density, a hydrolyzable silane and / or a partially hydrolyzed condensate thereof may be added as a component (D) to the thermosetting organopolysiloxane composition of the present invention. The component (D) needs to have in one molecule a silicon atom to which at least two hydrolyzable groups are bonded. Component (D) is represented by the following general formula (2)
R ¹ _a SiX _4-a (2)
(In the formula, each R ¹ is an independent unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, X is an independent hydrolyzable group, and a is an integer of 0 to 2) It is preferable that it is the silane represented by these, and / or its partial hydrolysis-condensation product.

As X, those exemplified as the hydrolyzable group other than the hydroxyl group among Y of the component (A) can be similarly used. X is preferably an alkoxy group, a ketoxime group, or an isopropenoxy group.
a is preferably 0 or 1 (that is, 3 or more of X are bonded to a silicon atom). The molecular structure of component (D) may be either a silane or siloxane structure, and in the case of a siloxane structure, it may be linear, branched or cyclic.
Examples of R ¹ include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group; a cycloalkyl group such as a cyclopentyl group and a cyclohexyl group; an aryl group such as a phenyl group and a tolyl group; Aralkyl groups such as benzyl group and 2-phenylethyl group; Alkenyl groups such as vinyl group, allyl group, butenyl group, pentenyl group and hexenyl group; 3,3,3-trifluoropropyl group, 3-chloropropyl group and the like Examples include halogenated alkyl groups. Among these, a methyl group, an ethyl group, a phenyl group, and a vinyl group are preferable.

  (D) It is preferable that the compounding quantity of a component is 0.5-20 mass parts with respect to 100 mass parts of (A) component, More preferably, it is 1-10 mass parts. When the blending amount of component (D) exceeds 20 parts by mass, the cured product may become too hard or economically disadvantageous.

  Specific examples of the component (D) include, for example, ethyl silicate, propyl silicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, methyltris (methoxyethoxy) silane, vinyltris (methoxyethoxy). Silane, methyltripropenoxysilane, methyltriacetoxysilane, vinyltriacetoxysilane, methyltri (methylethylketoxime) silane, vinyltri (methylethylketoxime) silane, phenyltri (methylethylketoxime) silane, propyltri (methylethylketoxime) silane, tetra ( Methylethylketoxime) silane, 3,3,3-trifluoropropyltri (methylethylketoxime) silane, 3-chloropropyltri (methylethyl) Ruketokishimu) silane, methyltri (dimethyl ketoxime) silane, methyltri (diethyl ketoxime) silane, methyltri (methyl isopropyl ketoxime) silane, tri (cyclohexanoxime) silane, and partial hydrolytic condensates thereof. These can be used individually by 1 type or in combination of 2 or more types.

  In addition, the thermosetting organopolysiloxane composition of the present invention includes a plasticizer, a colorant such as a pigment, a flame retardant, a thixotropic agent, an antibacterial and antibacterial agent, so-called carbon functional silane as necessary. Adhesion improvers such as (for example, alkoxysilanes having amino groups, epoxy groups, thiol groups, etc. such as γ-glycidoxypropyltrimethoxysilane and aminopropyltriethoxysilane) do not inhibit the effects of the present invention. You may mix | blend suitably in the range.

The thermosetting organopolysiloxane composition of the present invention is cured by the reaction of the components (A) and (B) during use. Therefore, before use, the composition is in such a form that the components (A) and (B) (and (C) and (D) as necessary) are present in an unreacted state.
And the thermosetting organopolysiloxane composition of this invention hardens | cures by mixing said (A), (B) component and (C), (D) component according to a conventional method as needed. Provided for use. Moreover, the curing conditions of the obtained composition are not particularly limited as long as it is heat-cured, but the heat-curing temperature is preferably 60 ° C. or higher. When the heat curing temperature is less than 60 ° C., the crosslinking reaction by the component (B) may not be sufficient. The heating time can be adjusted depending on the process.

<Example>
EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Further, “parts” and “%” shown in the examples represent parts by mass and mass% unless otherwise specified.

Hydroxyl end-capped dimethylpolysiloxane having a viscosity of 20,000 mPa · s at 25 ° C.—100 parts (component A: R = CH ₃ , U = O, m = 2, n = 615 in formula (1), The same as in Examples and Comparative Examples) and 1 part (component B) of acetylacetonate copper (II) were mixed until uniform to prepare a thermosetting organopolysiloxane composition. The viscosity of component A was measured with a rotational viscometer.
The obtained composition was filled into a glass petri dish, (1) heated for 24 hours in a 60 ° C. dryer, (2) heated for 3 hours in a 150 ° C. dryer, and (3) 23 ° C., 50%. After leaving for 5 days in RH, the presence or absence of curing was visually confirmed for each of the three conditions.

  A thermosetting organopolysiloxane composition was prepared and cured in exactly the same manner as in Example 1 except that 1 part of acetylacetonate iron (III) was added instead of 1 part of acetylacetonate copper (II). The condition was evaluated.

  A thermosetting organopolysiloxane composition was prepared and cured in the same manner as in Example 1 except that 1 part of acetylacetonate zinc (II) was blended in place of 1 part of acetylacetonate copper (II). The condition was evaluated.

  A thermosetting organopolysiloxane composition was prepared and cured in exactly the same manner as in Example 1 except that 1 part of acetylacetonate zirconium (IV) was added instead of 1 part of acetylacetonate copper (II). The condition was evaluated.

  A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 1 except that a trimethoxy group was used instead of a hydroxyl group as a terminal group of the component A, and the cured state was evaluated.

  A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 2 except that a trimethoxy group was used instead of a hydroxyl group as a terminal group of the component A, and the cured state was evaluated.

  A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 3 except that a trimethoxy group was used in place of the hydroxyl group as the terminal group of the component A, and the cured state was evaluated.

  A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 4 except that a trimethoxy group was used instead of a hydroxyl group as a terminal group of the component A, and the cured state was evaluated.

  A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 1 except that a trimethoxysylethylene group was used in place of the hydroxyl group as the terminal group of the component A, and the cured state was evaluated.

  A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 2 except that a trimethoxysilethylene group was used in place of a hydroxyl group as a terminal group of the component A, and the cured state was evaluated.

  A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 3 except that a trimethoxysylethylene group was used instead of a hydroxyl group as a terminal group of the component A, and the cured state was evaluated.

  A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 4 except that a trimethoxysylethylene group was used in place of the hydroxyl group as the terminal group of the component A, and the cured state was evaluated.

  Furthermore, a thermosetting organopolysiloxane composition was prepared in the same manner as in Example 1 except that 1 part of 3-aminopropyltriethoxysilane was added as an amine component, and the cured state was evaluated.

  Furthermore, a thermosetting organopolysiloxane composition was prepared in the same manner as in Example 2 except that 1 part of 3-aminopropyltriethoxysilane was added as an amine component, and the cured state was evaluated.

<Comparative Example 1>
A thermosetting organopolysiloxane composition was prepared and cured exactly as in Example 1 except that 1 part of acetylacetonate manganese (III) was added instead of 1 part of acetylacetonate copper (II). The condition was evaluated.

<Comparative Example 2>
A thermosetting organopolysiloxane composition was prepared and cured in the same manner as in Example 1 except that 1 part of acetylacetonate cobalt (III) was added instead of 1 part of acetylacetonate copper (II). The condition was evaluated.

<Comparative Example 3>
A thermosetting organopolysiloxane composition was prepared and cured exactly as in Example 1, except that 1 part of acetylacetonate nickel (II) was added instead of 1 part of acetylacetonate copper (II). The condition was evaluated.

<Comparative Example 4>
A thermosetting organopolysiloxane composition was prepared and cured in exactly the same manner as in Example 5 except that 1 part of acetylacetonate manganese (III) was added instead of 1 part of acetylacetonate copper (II). The condition was evaluated.

<Comparative Example 5>
A thermosetting organopolysiloxane composition was prepared and cured in the same manner as in Example 9 except that 1 part of acetylacetonate manganese (III) was blended in place of 1 part of acetylacetonate copper (II). The condition was evaluated.

<Comparative Example 6>
A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 1 except that 1 part of copper powder was added instead of 1 part of acetylacetonate copper (II), and the cured state was evaluated.

<Comparative Example 7>
A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 1 except that 1 part of zinc powder was added instead of 1 part of acetylacetonate copper (II), and the cured state was evaluated.

<Comparative Example 8>
A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 1 except that 1 part of iron powder was added instead of 1 part of acetylacetonate copper (II), and the cured state was evaluated.

<Comparative Example 9>
A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 2 except that a dimethylvinylsiloxy group was used in place of the hydroxyl group as the terminal group of the component A, and the cured state was evaluated.

<Comparative Example 10>
A thermosetting organopolysiloxane composition was prepared in the same manner as in Example 2 except that a trimethylsiloxy group was used instead of a hydroxyl group as a terminal group of the component A, and the cured state was evaluated.

<Comparative Example 11>
100 parts of vinyl end-capped organopolysiloxane (V-Sx; Vi-Me ₂ -Si-O-(-Si-Me ₂ -O-) ₄₀₀ -Si-Me ₂ -Vi; viscosity 4990 mPa · S) and hydro Genpolysiloxane (H-Sx; Me ₃ -Si-O-(-Si-Me ₂ -O-) ₁₅ -(-Si-MeH-O-) ₂₀ Si-Me ₃ ; Viscosity 50 mPa · S) 2.5 parts A platinum catalyst (platinum and 1,2-divinyl-1,1,2,2-tetramethyl-disiloxane complex / toluene solution; Pt = 0.5 wt%) and a control agent (ethynyl-cyclohexanol / (Toluene solution; 50 wt%) was mixed with 0.2 part until uniform to prepare a thermosetting organopolysiloxane composition, and the cured state was evaluated.

<Comparative Example 12>
Further, a thermosetting organopolysiloxane composition was prepared in the same manner as Comparative Example 11 except that 1 part of 3-aminopropyltriethoxysilane was added as an amine component, and the cured state was evaluated.

  The obtained results are shown in Table 1.

  As is clear from Table 1, in each example, it was sufficiently cured by heating at 60 ° C. and 150 ° C. Further, in Examples 13 and 14 in which amine was contained in the heat-curable organopolysiloxane composition of Examples 1 and 2, it was found that heat curing was performed even in the presence of amine.

On the other hand, in the case of Comparative Examples 1-5 using a metal complex of manganese, cobalt, or nickel instead of the component (B), the composition did not heat cure. In addition, in the case of Comparative Examples 6 to 8 using metal powder instead of the component (B), the composition was not heat cured.
In the case of Comparative Examples 9 and 10 using a group that did not hydrolyze instead of a hydroxyl group as a terminal group of the component A, the composition did not heat cure.
Comparative Example 11 is a reference example of a conventional thermosetting organopolysiloxane composition using a SiH group-containing siloxane and a platinum catalyst, and requires an expensive platinum catalyst.
In the case of Comparative Example 12 in which an amine was contained in a conventional heat-curable organopolysiloxane composition (Comparative Example 11), the resin was not heat-cured because of the presence of amine.

Claims (4)

And at least two have a silicon atom (A) a hydroxyl and / or hydrolyzable group is bonded in one molecule, and the diorganopolysiloxane having a viscosity at 25 ° C. is 20~1000000mPa · s,
(B) Thermosetting organopolysiloxane composition containing 0.01 to 20 parts by mass per 100 parts by mass of component (A) and containing an acetylacetonate complex of a metal selected from the group consisting of zinc, copper and iron object. The (A) diorganopolysiloxane has the following general formula (1)
(In the formula, R is an independent unsubstituted or monovalent hydrocarbon group substituted with a halogen atom and / or a cyano group, U is an independent oxygen atom or a divalent hydrocarbon group having 1 to 8 carbon atoms, Y Are independent hydroxyl groups or hydrolyzable groups, m is an integer of 0 to 2, and n is a natural number such that the viscosity of the obtained diorganopolysiloxane at 25 ° C. is 20 to 1,000,000 mPa · s). The heat-curable organopolysiloxane composition according to claim 1 , which is represented by: (C) The filler further comprises 1 to 50 parts by mass of hydrophilic silica and / or hydrophobic silica having a BET specific surface area of 10 m ² / g or more based on 100 parts by mass of the component (A). Item 3. The heat-curable organopolysiloxane composition according to Item 1 or 2 . The thermosetting organopolysiloxane composition according to any one of claims 1 to 3 , wherein the thermosetting temperature is 60 ° C or higher.