WO2022024734A1

WO2022024734A1 - Thermal radical curable organopolysiloxane composition, article adhered, coated, or potted with said composition, and method for producing cured product of said composition

Info

Publication number: WO2022024734A1
Application number: PCT/JP2021/026130
Authority: WO
Inventors: 晃嗣藤原; 隆文坂本
Original assignee: 信越化学工業株式会社
Priority date: 2020-07-28
Filing date: 2021-07-12
Publication date: 2022-02-03
Also published as: JPWO2022024734A1

Abstract

Provided is a composition which contains a highly industrially versatile alkenyl group-containing organopolysiloxane and an organopolysiloxane having a hydrolysable silyl group at both ends of the molecular chain as base polymers, in combination with a crosslinking agent, a radical initiator, a moisture-curing initiator, and an inorganic filler. A thermal radical curable organopolysiloxane composition, in which the ratio (H₂/H₁) of the hardness (H₂) of a cured product of a secondary curing (1 day in an environment of 23°C and 50% RH) to the hardness (H₁) of a cured product of a primary curing (5-60 minutes at 80-150°C) is 1.00-1.20, is stable, can complete curing in a relatively short time, can give a cured product having a reduced oxygen inhibition effect, and can achieve low odor properties.

Description

A method for producing a thermally radically curable organopolysiloxane composition, an article bonded, coated or potted with the composition, and a cured product of the composition.

The present invention relates to a stable and thermally radically curable organopolysiloxane composition, more specifically, an organopolysiloxane having at least two alkenyl groups bonded to a silicon atom in one molecule, and a hydrolyzable silyl group as a molecular chain. Thermal radical curable organopolysiloxane composition containing organopolysiloxane, cross-linking agent, radical initiator, moisture curing initiator, and inorganic filler at both ends, bonded, coated or potted with the cured product of the composition. The present invention relates to an article and a method for producing a cured product of the composition.

A curable organopolysiloxane composition that cures to become an elastomer material (silicone rubber cured product) is already known. Examples of the curing method include moisture curing (condensation curing), thermal curing (hydrosilylated addition curing or radical curing with organic peroxide), radiation curing (radical curing with ultraviolet rays), and the like.

Moisture curing is a room temperature curable (RTV) silicone rubber composition that is crosslinked and cured by a condensation reaction at room temperature (23 ° C ± 15 ° C) due to the humidity in the air. It is easy to handle, and has weather resistance and electricity. Due to its excellent properties, it is used in various fields such as sealing materials for building materials and adhesives in the electrical and electronic fields. These RTV silicone rubber compositions are often designed starting from an organopolysiloxane (base polymer) having a silanol group or a hydrolyzable silyl group at the end. As the curing type of the room temperature curable (RTV) silicone rubber composition, a de-alcohol type, a de-oxime type, and a de-acetic acid type are generally known and are used in various applications. For example, in the de-alcohol type, it is widely used in component fixing adhesives and coating agents for electrical and electronic equipment, adhesives for automobiles, and the like. Since the de-oxime type and de-acetic acid type have relatively fast curability, they are often used mainly as sealing materials for building materials. I have a problem with. In addition, de-oxime type and deacetic acid type are also concerned about corrosiveness to adherends, so caution is required when using them. In all of these curing types, the curing progresses from the surface portion that comes into contact with the humidity in the air toward the inside, so the time until the curing is completed is greatly affected by the humidity. Moreover, since the reaction rate differs depending on the temperature, the curing rate changes depending on the environment in which it is used. Therefore, it is known that it is not suitable for applications such as thick places and large-area bonding.

In the thermosetting type, a composition containing an organopolysiloxane having an alkenyl group bonded to a silicon atom and an organohydrogensiloxane having a hydrogen atom (SiH group) bonded to a silicon atom is hydrosilylated by heating in the presence of a platinum-based catalyst. An addition reaction curing type organopolysiloxane composition for obtaining a cured elastic body (silicone rubber elastic body) by subjecting it to a chemical addition reaction is generally known. The thermosetting type by addition reaction does not require moisture for curing, cures in a relatively short time, and can be applied to thick places and large areas of bonding. However, if a compound having an unshared electron pair such as nitrogen, phosphorus, or sulfur (for example, an amine compound or an organic phosphorus compound), an organic acid such as a flux, or an organic tin is present at the application site, platinum may be produced by these compounds. The catalyst is inactivated and hardening inhibition can occur. As a result, sufficient properties originally required may not be exhibited.

For radiation curing, a UV-curable organopolysiloxane composition that is generally cured by radicals generated by irradiation with UV light (ultraviolet rays) is widely known. By containing an organopolysiloxane having an acrylic group or a vinyl group as a radical functional group and a compound (radical initiator) that generates a radical by UV light, the organopolysiloxanes are bonded to each other to form an elastomer material. Generally, many compositions are cured by UV light irradiation within 60 seconds, and are characterized by quick curing. However, the odor of acrylic groups is strong, and the adhesiveness is often insufficient. Further, it is known that the surface does not harden because it is a radical reaction and is hindered by oxygen. Curing in a nitrogen atmosphere can solve this problem, but it requires the introduction of dedicated equipment and the problem of asphyxiation must be fully taken into consideration.

Further, as a method for generating radicals other than radiation curing, a method by thermosetting using an organic peroxide is also known (peroxide curing type organopolysiloxane composition). However, as with the organopolysiloxane composition by UV light, the surface of the elastomer may be uncured due to oxygen inhibition due to the radical reaction. As a method for improving this, Patent Document 1 (Japanese Patent No. 6385370) exemplifies a silicone pressure-sensitive adhesive composition that is cured by condensation curing and thermal radical curing. Condensation curing and thermal radical curing can be achieved by using a clustered functional organopolysiloxane having a radical curable group selected from an acrylate group and a methacrylate group and a reactive polymer having an alkoxy group. The silicone pressure-sensitive adhesive composition obtained by the method described in Patent Document 1 has a demerit of oxygen inhibition because it is a system in which the surface of the composition subjected to oxygen inhibition by thermal radical curing is gradually cured by condensation curing. No. However, since the preparation of the clustered functional organopolysiloxane is complicated, the versatility is poor, and since it has an acrylate group and a methacrylate group, it has a strong odor.

Further, Patent Document 2 (International Publication No. 2018/186165) discloses a curing-reactive organopolysiloxane composition having a radical-reactive group and a condensation-reactive group. Storage elastic modulus G'1 of the cured product primary cured (condensation curing) at room temperature and storage elastic modulus _G'1 of the cured product secondary cured (thermal radical curing) by further heating the cured product at 100 ° C. or higher. For ' ₂ , the rate of increase of _G'2 with respect to G'1 is at _least 50%. The composition is highly useful as an organopolysiloxane composition that can be primary cured by moisture curing in a room temperature environment and then thermally radically cured (secondary curing), but is cured at room temperature (primary curing). The rate of increase of _G'2 with respect to _G'1 may fluctuate with time. In addition, since the time due to moisture curing (primary curing) is long, there is a demerit that the tact time in actual use becomes long.

Japanese Patent No. 6385370 International Publication No. 2018/186165

The present invention has been made in view of the above circumstances, and it is possible to provide a cured product (silicone rubber cured product) which can complete curing in a relatively short time and has a reduced effect of oxygen inhibition. Further, a stable and thermally radically curable organopolysiloxane composition having a low odor property, an article bonded, coated or potted with a cured product of the composition, and a cured product of the composition are produced. The purpose is to provide a method.

As a result of diligent studies to achieve the above object, the present inventors have found that industrially versatile alkenyl group-containing organopolysiloxane (particularly, organopolysiloxane containing alkenyl groups at both ends of the molecular chain) and the molecular chain. An organopolysiloxane composition in which an organopolysiloxane having a hydrolyzable silyl group at both ends is used as a base polymer and a cross-linking agent, a radical initiator, a water curing initiator, and an inorganic filler are combined is stable. An organopolysiloxane composition that can be thermally radically cured is obtained, and in particular, after being thermally radically cured in a relatively short time under the conditions of 80 to 150 ° C. as the primary curing, in a room temperature environment of 40 ° C. or lower as the secondary curing. By further curing the surface of the primary cured product by moisture curing for 1 day (24 hours), the primary / secondary curing can be completed in a relatively short time, and the primary / secondary curing can be completed. We have found that a thermoradical curable organopolysiloxane composition that can provide a cured product (cured silicone rubber product) with reduced effects of oxygen inhibition and that also achieves low odor can be obtained. I came to the point.

That is, the present invention provides the following thermally radical curable organopolysiloxane composition, an article bonded, coated or potted with the cured product of the composition, and a method for producing the cured product of the composition. It is a thing.
[1]
(A) Organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass,
(B) The following general formula (1)

(In the formula, R ¹ is an independently unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, n is an integer of 10 or more, and R ² is independently non-substituted with 1 to 6 carbon atoms. It is a substituted or substituted monovalent hydrocarbon group, X is an oxygen atom or an alkylene group having 1 to 4 carbon atoms, and a is 0 or 1 independently for each silicon atom to be bonded.)
Organopolysiloxane indicated by: 5-80 parts by mass,
(C) A (organo) silane compound having 3 or more hydrolyzable groups in one molecule and / or a partially hydrolyzed condensate thereof: 0.1 to 30% by mass with respect to the content of the component (B). amount,
(D) Radical initiator: 0.1 to 20 parts by mass,
(E) Moisture curing initiator: 0.01 to 10% by mass with respect to the content of the component (B),
(F) Inorganic filler: An organopolysiloxane composition containing an amount of 1 to 500% by mass based on the total amount of the components (A) and (B), and 80 to 150 as the primary curing. The hardness (H ₁ ) of the cured product obtained by heat-curing at ° C for 5 to 60 minutes, and as the secondary curing, the cured product was further subjected to an environment of a temperature of 23 ° C and a humidity of 50% RH for 1 day (H 1). 24 hours) A product that gives a cured product in which the ratio of H ₂ to H ₁ (H ₂ / H ₁ ) is 1.00 to 1.20 with respect to the hardness (H ₂ ) of the cured product after being cured by moisture. An organopolysiloxane composition that is thermosetting.
[2]
Further, the thermally radical curable organopolysiloxane according to [1], wherein (G) contains 1 to 20 parts by mass of an organic compound having two or more allyl groups in one molecule with respect to 100 parts by mass of the component (A). Composition.
[3]
The component (C) is organotrialkoxysilane, tetraalkoxysilane, tetraalkoxydisilane compound, tetraalkoxytrisilane compound, hexaalkoxydisilane compound, hexaalkoxytrisilane compound, (organo) acetoxysilane, (organo) isopropenoxysilane. The thermal radical curable organopolysiloxane composition according to [1] or [2], which is one or more selected from the group consisting of (organo) ketooxymsilane.
[4]
The thermally radical curable organopolysiloxane composition according to any one of [1] to [3], wherein the component (E) is an organic titanium compound or an organic tin compound.
[5]
An article bonded, coated or potted with a cured product of the thermally radically curable organopolysiloxane composition according to any one of [1] to [4].
[6]
The thermally radical curable organopolysiloxane composition according to any one of [1] to [4] can be thermally radically cured, including a step of thermally radical curing at 80 to 150 ° C. and then condensation curing at room temperature. A method for producing a cured product of an organopolysiloxane composition.

According to the present invention, it has an industrially versatile alkenyl group-containing organopolysiloxane (particularly, an organopolysiloxane containing an alkenyl group at both ends of the molecular chain) and a hydrolyzable silyl group at both ends of the molecular chain. By using organopolysiloxane in combination as a base polymer, it becomes an organopolysiloxane composition that is stable (especially good storage stability) and can be thermally radically cured. After thermal radical curing in a short period of time, the surface of the cured product, which was first cured in a room temperature environment of 40 ° C. or lower as the secondary curing, is further secondarily cured by moisture curing for a relatively short time. It is possible to complete the primary / secondary curing in the meantime, and it is possible to give a cured product (silicone rubber cured product) with a reduced effect of oxygen inhibition, and further, heat that realizes low odor. It is possible to provide an organopolysiloxane composition that can be radically cured.

Hereinafter, the present invention will be described in detail.
[(A) component]
The component (A) is the first base polymer of the composition of the present invention (that is, a base polymer having thermal radical curability), and is an organopoly having at least two alkenyl groups bonded to silicon atoms in one molecule. It is a siloxane. The molecular structure of the component (A) is not particularly limited, and examples thereof include a linear structure and a cyclic structure, and these structures may have branches. In particular, a linear diorganopolysiloxane in which the main chain basically consists of repeating diorganosiloxane units and both ends of the molecular chain are sealed with a triorganosyloxy group is preferably used.

The viscosity of the component (A) at 25 ° C. is preferably in the range of 100 to 500,000 mPa · s, and particularly preferably in the range of 100 to 100,000 mPa · s. When the viscosity is within the above range, the handling workability of the composition and the physical strength of the elastomer material (silicone rubber cured product) obtained from the composition can be sufficiently ensured. Viscosity can usually be measured at 25 ° C. with a rotational viscometer (eg, BL type, BH type, BS type, cone plate type, rheometer, etc.).

The degree of polymerization of the alkenyl group-containing organopolysiloxane having the above viscosity (the number of silicon atoms in the molecule or the number of repetitions of the diorganosiloxane unit constituting the main chain) is usually 50 to 2,000, particularly 80 to 80. About 1,200 is preferable. In the present invention, the degree of polymerization can be determined as a polystyrene-equivalent number average degree of polymerization (or number average molecular weight) or the like in gel permeation chromatography (GPC) analysis using, for example, toluene or the like as a developing solvent.

In the alkenyl group-containing organopolysiloxane of the component (A), the alkenyl group bonded to the silicon atom is preferably one having 2 to 8 carbon atoms and further preferably 2 to 4 carbon atoms, and for example, a vinyl group, an allyl group and a butenyl group. , Pentenyl group, hexenyl group, heptenyl group and the like. Of these, a vinyl group is preferable. When the organopolysiloxane has a linear structure, the alkenyl group may be bonded to a silicon atom at the end of the molecular chain but to a silicon atom in the side chain of the molecular chain (non-terminal of the molecular chain). It may be either of these, but it is preferable that it has an alkenyl group bonded to a silicon atom at both ends of the molecular chain, and both ends of the molecular chain are blocked by a triorganosilyl group having an alkenyl group. More preferably, it is a linear diorganopolysiloxane.

In the alkenyl group-containing organopolysiloxane of the component (A), the organic group other than the alkenyl group bonded to the silicon atom may be an unsubstituted or halogen-substituted monovalent hydrocarbon group, for example, a methyl group, an ethyl group, etc. Alkyl group having 1 to 10 carbon atoms such as propyl group, butyl group, pentyl group, hexyl group, cyclohexyl group, heptyl group and decyl group; Aryl group; aralkyl group having 7 to 14 carbon atoms such as benzyl group and phenethyl group; 1 to 3 carbon atoms such as chloromethyl group, bromoethyl group, 3-chloropropyl group and 3,3,3-trifluoropropyl group. Examples thereof include an alkyl halide group. Of these, a methyl group and a phenyl group are preferable.

The linear diorganopolysiloxane includes a trimethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer at both ends of the molecular chain and a trimethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer at both ends of the molecular chain. , Molecular chain double-ended dimethylvinylsiloxy group-blocked dimethylpolysiloxane, Molecular chain double-ended dimethylvinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer, Molecular chain double-ended dimethylvinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methyl Examples thereof include a phenylsiloxane copolymer and a trivinylsiloxy group-blocked dimethylpolysiloxane having both ends of the molecular chain. The organopolysiloxane having a cyclic structure or a branched structure is represented by the formula: R ³ ₃ SiO _0.5 (R ³ is an unsubstituted or substituted monovalent hydrocarbon group other than an alkenyl group; the same applies hereinafter). Unit and formula: R ³ ₂ R ⁴ SiO _0.5 (R ⁴ is an alkenyl group; the same shall apply hereinafter) Siloxane unit and formula: R ³ ₂ SiO siloxane unit and formula: SiO ₂ Organosiloxane copolymer consisting of a siloxane unit, from a hydrocarbon unit represented by the formula: R ³ ₃ SiO _0.5 and a hydrocarbon unit represented by the formula: R ³ ₂ R ⁴ SiO _0.5 and a siloxane unit represented by the formula: SiO ₂ Organosiloxane copolymer, which consists of a siloxane unit represented by the formula: R ³ ₂ R ⁴ SiO and a siloxane unit represented by the formula: R ³ SiO _1.5 or a siloxane unit represented by the formula: R ⁴ SiO _1.5 . Examples include polymers.

In the above formula, R ³ is an unsubstituted or substituted monovalent hydrocarbon group other than the alkenyl group, which is the same as that exemplified as the organic group other than the alkenyl group described above, and is, for example, a methyl group, an ethyl group and a propyl group. An alkyl group having 1 to 10 carbon atoms such as a group, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group, a heptyl group and a decyl group; and an aryl having 6 to 14 carbon atoms such as a phenyl group, a trill group, a xylyl group and a naphthyl group. Group; Aralkyl group having 7 to 14 carbon atoms such as benzyl group and phenethyl group; Halogen having 1 to 3 carbon atoms such as chloromethyl group, bromoethyl group, 3-chloropropyl group and 3,3,3-trifluoropropyl group Examples thereof include an alkylated group. Further, R ⁴ is preferably an alkenyl group having 2 to 8 carbon atoms and further preferably a 2 to 4 carbon atoms, and examples thereof include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group and a heptenyl group.

The alkenyl group-containing organopolysiloxane of the component (A) can be used alone or in combination of two or more.

[(B) component]
The component (B) is a second base polymer of the composition of the present invention (that is, a base polymer having moisture curability (condensation curability)), and two or three silicons at both ends of the molecular chain, respectively. It is a linear organopolysiloxane sealed with a hydrolyzable silyl group having an organooxy group bonded to an atom, and is represented by the following general formula (1).

(In the formula, R ¹ is an independently unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, n is an integer of 10 or more, and R ² is independently non-substituted with 1 to 6 carbon atoms. It is a substituted or substituted monovalent hydrocarbon group, X is an oxygen atom or an alkylene group having 1 to 4 carbon atoms, and a is 0 or 1 independently for each silicon atom to be bonded.)

In the above formula (1), R ¹ is an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, and is, for example, a methyl group, an ethyl group, a propyl group, or a butyl group. Linear or branched alkyl group such as group, pentyl group, hexyl group, heptyl group, decyl group; cyclic alkyl group such as cyclohexyl group; vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group and the like. Alkenyl groups; aryl groups such as phenyl group, trill group, xylyl group, naphthyl group; aralkyl groups such as benzyl group and phenethyl group; and groups in which the hydrogen atom of these groups is partially substituted with a halogen atom, for example. Examples thereof include a chloromethyl group, a bromoethyl group, a 3-chloropropyl group, a 3,3,3-trifluoropropyl group and a chlorophenyl group. Among these, an unsubstituted monovalent hydrocarbon group having no aliphatic unsaturated bond (for example, an alkyl group, an aryl group, an aralkyl group, etc.) is preferable, an alkyl group or an aryl group is more preferable, and a methyl group is particularly preferable. Is preferable. Further, the plurality of R ^1s may be the same group or different groups.

N (the number of repetitions of the diorganosiloxane unit) in the above formula (1) is an integer of 10 or more, and is usually an integer of 10 to 2,000, preferably an integer of 20 to 1,500, and more preferably 30 to. It is an integer of 1,000, more preferably an integer of 50 to 800. Further, the value of n is an integer in which the viscosity of the organopolysiloxane of the component (B) at 25 ° C. is in the range of 25 to 500,000 mPa · s, preferably in the range of 100 to 100,000 mPa · s. Is desirable.

In the present invention, n (or the number of repetitions of the bifunctional diorganosiloxane unit represented by ((R ¹ ) ₂ SiO _2/2 ) constituting the main chain of the organopolysiloxane of the component (B)). The degree of polymerization) can usually be determined as a polystyrene-equivalent number average degree of polymerization (or number average molecular weight) or the like in gel permeation chromatography (GPC) analysis using toluene or the like as a developing solvent. Further, the viscosity can usually be measured at 25 ° C. with a rotational viscometer (for example, BL type, BH type, BS type, cone plate type, rheometer, etc.).

In the above formula (1), X is an oxygen atom or an alkylene group having 1 to 4 carbon atoms, and examples of the alkylene group having 1 to 4 carbon atoms include a methylene group, an ethylene group, a propylene group and a butylene group. A chain alkylene group and isomers thereof, for example, an isopropylene group and an isobutylene group are applicable. As X, an oxygen atom and an ethylene group are particularly preferable.
In the case of an ethylene group, it is very versatile because it can be easily produced by an addition reaction of the corresponding hydrosilane with the α, ω-divinyl-terminated organopolysiloxane in the presence of a metal catalyst.

Further, in the above formula (1), R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, and is, for example, an alkyl group such as a methyl group, an ethyl group or a propyl group; a methoxymethyl group, Alkoxy-substituted alkyl groups such as methoxyethyl group, ethoxymethyl group and ethoxyethyl group; cyclic alkyl groups such as cyclohexyl group; alkenyl groups such as vinyl group, allyl group and propenyl group, phenyl group and the like, and particularly methyl group. , Ethyl groups are preferred.

A is independently 0 or 1 for each silicon atom to be bonded, and is particularly preferably 0.

Examples of the component (B) include those shown below.

(In the formula, n1 is a number in which the viscosity of the organopolysiloxane at 25 ° C. is in the range of 25 to 500,000 mPa · s.)

The organopolysiloxane of the component (B) may be used alone or in combination of two or more.
In the composition of the present invention, the blending amount of the organopolysiloxane of the component (B) is 100 parts by mass of the component (A) from the viewpoint of the balance between the thermal radical curability and the moisture (condensation) curability of the composition. On the other hand, it is 5 to 80 parts by mass, preferably 10 to 60 parts by mass, and more preferably 15 to 40 parts by mass. If the amount of the component (B) is less than 5 parts by mass, moisture (condensation) curing does not proceed sufficiently, and it may be difficult to sufficiently moisture (condensate) cure the surface of the cured product subjected to oxygen inhibition. If it exceeds, it may be difficult to cure for a short time due to thermal radical curability.

[(C) component]
The component (C) is a (organo) silane compound having three or more hydrolyzable groups in one molecule and / or a partially hydrolyzed condensate thereof, and hydrolyzes and condenses with the above component (B) by moisture. It acts as a cross-linking agent (hardener) that cross-links (hardens). The (organo) silane compound having three or more hydrolyzable groups in one molecule is preferably hydrolyzable (preferably hydrolyzable (organo) having three or more hydrolyzable groups in one molecule represented by the following general formula (2). Organo) A silane compound, or a bissilane type compound or a trisilane type compound having 3 or more (particularly 4 to 6) hydrolyzable groups in one molecule.
In the present invention, the partially hydrolyzed condensate is produced by partially hydrolyzing and condensing the hydrolyzable (organo) silane compound, and at least two, preferably three or more, in one molecule. In particular, it means a (organo) siloxane oligomer having 3 to 6 residual hydrolyzable groups.

(R ⁵ ) _3-m SiY _m (2)
(In the formula, R ⁵ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, Y is an independently hydrolyzable group, and m is 3 or 4).

In the above formula (2), R ⁵ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a heptyl group and a decyl. Alkyl groups such as groups; alkenyl groups such as vinyl groups, allyl groups, butenyl groups, pentenyl groups, hexenyl groups and heptenyl groups; aryl groups such as phenyl groups, trill groups, xsilyl groups and naphthyl groups; benzyl groups, phenethyl groups and the like Aralkyl group; chloromethyl group, bromoethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, halogen-substituted alkyl group such as chlorophenyl group, halogen-substituted aryl group and the like can be mentioned. Among these, an alkyl group is preferable, and a butyl group, a hexyl group, a heptyl group, and a decyl group are particularly preferable.

In the above formula (2), the hydrolyzable groups of Y are independently, for example, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group and the like having 1 to 4 carbon atoms, particularly 1 carbon atom. Or 2 alkoxy groups; alkoxy-substituted alkoxy groups having 2 to 4 carbon atoms such as methoxymethoxy group and methoxyethoxy group; ketooximes having 3 to 5 carbon atoms such as dimethylketooxime group, diethylketooxime group and ethylmethylketooxime group. Group; Alkoxyoxy group having 2 to 4 carbon atoms such as vinyloxy group, allyloxy group, propenoxy group, isopropenoxy group; acyloxy group having 2 to 4 carbon atoms such as acetoxy group and propeonoxy group; carbon number of carbon number 2 such as dimethylaminoxy group Examples thereof include the dialkylaminoxic group of 4 to 4, preferably an alkoxy group and an alkenyloxy group, and particularly preferably an alkoxy group.
In the above formula (2), m is 3 or 4.

The hydrolyzable (organo) silane compound of the component (C) is a silyl group having a hydrolyzable group such as two or three alkoxy groups such as a trialkoxysilyl group and a dialkoxy (organo) silyl group. Alkoxy-type compounds having 2 to 6 carbon atoms (that is, so-called bissilane-type compounds having 2 silyl groups at the end of the molecular chain), preferably having 2 to the end of the molecular chain (one at each end). Two hydrolyzable silyl groups such as a trialkoxysilyl group or a dialkoxy (organo) silyl group (at both ends) via an alkylene group such as an ethylene group or an alkenylene group such as an ethenylene group (vinylene group). A diorganosilylene compound having (one by one) (that is, a so-called trisilane type compound having three silyl groups or silylene groups in one molecule) can be used.

Here, in these bissilane type compounds and trisilane type compounds, as the hydrolyzable group, the same as those exemplified by Y in the above formula (2) can be exemplified, and the hydrolyzable group is bonded to a silicon atom other than the hydrolyzable group. As the group to be used, the same group as that exemplified by R ⁵ of the above-mentioned formula (2) can be exemplified.

Specific examples of the component (C) include methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane. Organotri such as n-propyltrimethoxysilane, n-propyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, isobutyltrimethoxysilane, n-hexyltrimethoxysilane, n-decyltrimethoxysilane Alkoxysilanes; tetraalkoxysilanes such as tetramethoxysilanes, tetraethoxysilanes, methylsilicates, ethylsilicates, methyl orthosilicates, ethyl orthosilicates and their partial hydrolysis condensates; 1,2-bis (dimethoxy (methyl) silyl) ethane. , 1,2-bis (diethoxy (methyl) silyl) ethane, 1,6-bis (dimethoxy (methyl) silyl) hexane, 1,6-bis (diethoxy (methyl) silyl) hexane and other tetraalkoxydisilane compounds; 1 Hexaalkenyl such as 2-bis (trimethoxysilyl) ethane, 1,2-bis (triethoxysilyl) ethane, 1,6-bis (trimethoxysilyl) hexane, 1,6-bis (triethoxysilyl) hexane. Disilane compounds; bis [2- (dimethoxy (methyl) silyl) ethyl] dimethylsilane, bis [2- (diethoxy (methyl) silyl) ethyl] dimethylsilane, bis [2- (dimethoxy (methyl) silyl) ethenyl] dimethylsilane , Tetraalkoxytrisilane compounds such as bis [2- (diethoxy (methyl) silyl) ethenyl] dimethylsilane, bis [2- (trimethoxysilyl) ethyl] dimethylsilane, bis [2- (triethoxysilyl) ethyl] dimethyl Hexaalkoxytrisilane compounds such as silane, bis [2- (trimethoxysilyl) ethenyl] dimethylsilane, bis [2- (triethoxysilyl) ethenyl] dimethylsilane; methyltriisopropenoxysilane, ethyltriisopropenoxysilane , Vinyl triisopropenoxysilane, (organo) isopropenoxysilane such as phenyltriisopropenoxysilane; methyltris (dimethylketooxym) silane, ethyltris (dimethylketooxym) silane, methyltris (methylethylketooxime) silane, ethyltris (methylethylke) (Organo) ketooxime silanes such as tooxime) silane, methyltris (methylisobutylketooxime) silane, ethyltris (methylisobutylketooxime) silane, vinyltris (methylethylketooxime) silane, phenyltris (methylethylketooxime) silane; methyltriacetoxysilane, Examples thereof include (organo) acetoxysilanes such as ethyltriacetoxysilanes and vinyltriacetoxysilanes.
As the component (C), one type may be used alone or two or more types may be used in combination.

The blending amount of the component (C) is 0.1 to 30% by mass, preferably 1 to 30% by mass, particularly preferably 1 to 25% by mass with respect to the content of the component (B). Is the amount. If the amount is less than 0.1% by mass, storage stability is lacking, sufficient cross-linking property due to moisture cannot be obtained, and it is difficult to obtain a cured product having the desired rubber elasticity. Further, if the amount exceeds 30% by mass, the obtained cured product tends to deteriorate in mechanical properties, and has drawbacks such as separation from the organopolysiloxane composition.

The hydrolyzable (organo) silane compound of the component (C) is a functional group containing at least one heteroatom selected from nitrogen, oxygen, and sulfur in the molecule, in addition to the hydrolyzable group Y. A silane coupling agent (ie, containing a carbon functional group) which is usually blended as an adhesion improver in a room temperature curable organopolysiloxane composition in that it does not have a monovalent hydrocarbon group substituted with. It is clearly distinguished from a hydrolyzable organosilane compound or a carbon functional silane).

[(D) component]
The component (D) is a radical initiator that generates radicals by heat, and is an important component for thermally radically curing the component (A). The component (D) is not particularly limited, but an organic peroxide is usually preferable, for example, dicumyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane. , Di-t-butyl peroxide, 2,5-di (t-butylperoxy) -2,5-dimethylhexane, 1,1-bis (t-amylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) ) Butane, 2,4-pentanedione peroxide, 2,5-bis (t-butylperoxy) -2,5-dimethylhexane, 2,5-di (t-butylperoxy) -2,5-dimethyl-3- Hexin, 2-butanone peroxide, benzoyl peroxide, cumene hydroperoxide, lauroyl peroxide, t-butyl hydroperoxide, t-butyl peroxybenzoate, t-butyl peroxy-2-ethylhexyl carbonate, di (2,4-dichlorobenzoyl) peroxide, Dichlorobenzoyl peroxide, di (t-butylperoxyisopropyl) benzene, di (4-methylbenzoyl) peroxide, di (2-methylbenzoyl) peroxide, butyl-4,4-di (t-butylperoxy) peroxide, 3,3 , 5,7,7-Pentamethyl-1,2,4-trioxepan, t-butylcumyl peroxide, di (4-t-butylcyclohexyl) peroxydicarbonate, disetylperoxydicarbonate, 2,3-dimethyl-2 , 3-Diphenylbutane, dioctanoyl peroxide, t-butylperoxy-2-ethylhexyl carbonate, t-amylperoxy-2-ethylhexanoate, 1,6-hexanediol-bis-t-butylperoxycarbonate, etc. Peroxides and combinations thereof can be mentioned.

The blending amount of the component (D) is in the range of 0.1 to 20 parts by mass, preferably 0.5 to 20 parts by mass, and particularly preferably 1 to 15 parts by mass with respect to 100 parts by mass of the component (A). If it is less than 0.1 part by mass, curability by thermal radicals is not exhibited, and it is difficult to obtain a cured product having the desired rubber elasticity. Further, if it exceeds 20 parts by mass, the desired rubber elasticity can be obtained, but there are disadvantages such as high cost.

[(E) component]
The water-curing initiator of the component (E) is used as a condensation reaction catalyst that accelerates curing by moisture, and is a Lewis acid, a primary, secondary, or tertiary organic amine compound, a metal oxide, or an organic titanium compound. , Organic tin compounds, organic zirconium compounds, or organic carboxylates of metals such as iron, antimony, bismuth, and manganese. The component (E) may be used alone or as a mixture of two or more.

Specific examples of the water-curing initiator include dibutyltin dilaurate, dibutyltin dioctate, dioctyltin dilaurate, dibutyltin malate ester, dimethyltindineodecanoate, dibutyltin dimethoxide, dioctyltin dineodecanoate, and star. Nasoctate, tetrabutyl titanate, tetra- (2-ethylhexyl) titanate, diisopropoxybis (acetylacetonate) titanium, diisopropoxybis (ethylacetoacetate) titanium, tetramethylguanidylpropyltrimethoxysilane and its like Examples include salt. Since the composition of the present invention has excellent curing properties by condensation curing, it is preferable to add an organic tin compound or an organic titanium compound, among which organic titanium compounds, particularly tetra- (2-ethylhexyl) titanate and diisopropoxybis ( Acetylacetate) titanium and diisopropoxybis (ethylacetacetate) titanium are preferable.

The amount of the component (E) added is 0.01 to 10% by mass, preferably 0.05 to 10% by mass, particularly preferably 0.1 with respect to the content of the component (B). It is an amount of up to 5% by mass. If the amount is less than 0.01% by mass, sufficient crosslinkability due to condensation hardening cannot be obtained. If the amount exceeds 10% by mass, there are drawbacks such as a disadvantage in terms of price and a decrease in the curing rate.

[(F) component]
The inorganic filler of the component (F) is a component added for the purpose of improving the strength, thixotropic property, flame retardancy, heat dissipation, etc. of the composition of the present invention, and specifically, pulverized silica and fumigant silica. (Fumed silica or dry silica), precipitate silica (wet silica), crystalline silica, spherical silica (molten silica), aluminum hydroxide, alumina, boehmite, magnesium hydroxide, magnesium oxide, calcium hydroxide, calcium carbonate, Examples thereof include zinc carbonate, basic zinc carbonate, zinc oxide, titanium oxide, carbon black, glass beads, glass balloons, resin beads, resin balloons, etc., which may be used alone or in combination of two or more. .. These inorganic fillers may not be surface-treated or may be surface-treated with a known treatment agent. As the known treatment agent, for example, the hydrolyzable group-containing polysiloxane described in JP-A-2000-256558 is preferable, but the treatment agent is not limited thereto.

The blending amount of the component (F) is 1 to 500% by mass, preferably 1 to 400% by mass, particularly preferably 1 to 1 to 500% by mass with respect to the total amount of the component (A) and the component (B). It is an amount of 200% by mass. If the amount is less than 1% by mass, the mechanical properties are poor. If the amount exceeds 500% by mass, it is difficult to obtain an organopolysiloxane composition that gives a cured product having rubber elasticity.

[Other ingredients]
In addition to the above components (A) to (F), the thermally radically curable organopolysiloxane composition of the present invention has, if necessary (in addition to the above components (A) to (F)), for the purpose of further improving the adhesiveness of the cured product to various substrates. G) As a component (arbitrary component), an aliphatic polyvalent carboxylic acid allyl ester such as diallyl malonate, diallyl awate, diallyl maleate, diallyl fumarate, diallyl phthalate, triallyl trimellitate, tetraallyl pyromellitic acid or fragrance. An organic compound having two or more (preferably 2 to 4) allyl groups in one molecule, such as a group polyvalent carboxylic acid allyl ester, is contained in an amount of 0 to 20 parts by mass, preferably 0 to 20 parts by mass with respect to 100 parts by mass of the component (A). About 1 to 10 parts by mass can be blended.

Further, in addition to the above components, an additive known as an additive for the organopolysiloxane composition may be added to the thermally radically curable organopolysiloxane composition of the present invention as long as the object of the present invention is not impaired. .. Examples thereof include polyether as a thixotropy improver, non-reactive dimethylsilicone oil as a plasticizer, isoparaffin, and a three-dimensional network methylpolysiloxane resin composed of trimethylsiloxy units and SiO ₂ units as a crosslink density improver. ..

Further, the thermally radically curable organopolysiloxane composition of the present invention may contain, if necessary, a colorant such as a pigment, a dye, a fluorescent whitening agent, a fungicide, an antibacterial agent, and a non-reactive phenyl as a bleed oil. Surface modifiers such as silicone oil, fluorosilicone oil, and organic liquids incompatible with silicone, and solvents such as toluene, xylene, solvent volatile oil, cyclohexane, methylcyclohexane, and low boiling point isoparaffin may also be added.

The thermally radical curable organopolysiloxane composition of the present invention is (A) an organopolysiloxane having at least two alkenyl groups bonded to a silicon atom in one molecule, and (B) two or two at both ends of the molecular chain. A linear organopolysiloxane sealed with a hydrolyzable silyl group having an organooxy group bonded to three silicon atoms, (C) a (organo) silane having three or more hydrolyzable groups in one molecule. It is formed by uniformly mixing a compound and / or a partially hydrolyzed condensate thereof, (D) a radical initiator, (E) a water curing initiator, and (F) an inorganic filler in any mixing order.

The thermally radically curable organopolysiloxane composition of the present invention is characterized in that the cross-linking reaction proceeds by radicals generated by heat, but the surface of the cured product poisoned by oxygen is gradually cured by the condensation reaction. ..
The method for curing the thermally radically curable organopolysiloxane composition of the present invention is more preferably after thermal radical curing at 80 to 150 ° C., particularly 100 to 130 ° C. for 5 to 60 minutes, particularly 10 to 30 minutes. Is preferably subjected to condensation curing at room temperature (23 ° C. ± 15 ° C.) for 12 to 36 hours, particularly 18 to 24 hours, in the air, more preferably in a humid environment.

The thermoradical curable organopolysiloxane composition of the present invention has the hardness (H ₁ ) of the cured product obtained by thermally curing at 80 to 150 ° C. for 5 to 60 minutes as the primary curing, and the secondary curing. As curing, the ratio of H ₂ to H ₁ (H) with respect to the hardness (H ₂ ) of the cured product after the cured product was further moisture-cured for 1 day in an environment of a temperature of 23 ° C. and a humidity of 50% RH. ₂ / H ₁ ) gives a cured product of 1.00 to 1.20, preferably 1.05 to 1.20. Here, the hardnesses H ₁ and H ₂ of the cured product are values measured by a type A durometer hardness tester according to JIS K 6249 (durometer type A hardness). When the ratio of H ₂ to H ₁ (H ₂ / H ₁ ) is less than 1.00, it means that the moisture curing has not progressed, and the surface of the cured product poisoned by oxygen does not cure. If it is larger than 1.20, thermal radical curing does not proceed so much and the desired curing characteristics may not be obtained.
In addition, in order to make the ratio of H ₂ to H ₁ (H ₂ / H ₁ ) in the above range, it can be achieved by mixing the component (A) and the component (B) in the blending ratio specified above. Moisture curing for one day means curing by allowing it to stand for 24 hours in an environment with a humidity of 50% RH.

The thermally radically curable organopolysiloxane composition of the present invention is useful as an adhesive, a coating agent, a potting agent, for example, liquid packing used in automobiles and electronics, coatings for various substrates, potting, sealants and the like. It can be used for various purposes. Further, it can be adhered to an adherend such as a metal such as aluminum, copper and stainless steel, and a polymer resin such as Fr-4, PBT, PPS and Bakelite. The method of using the thermally radically curable organopolysiloxane composition of the present invention as an adhesive, a coating agent, and a potting agent may follow a conventionally known method.

Hereinafter, examples and comparative examples that specifically explain the present invention will be shown, but the present invention is not limited to the following examples. The viscosity is a value measured by a B-type rotational viscometer, the specific surface area is a value measured by the BET adsorption method, and the room temperature means 23 ° C.

Preparation of Silicone Base A As a component (A), both ends of the molecular chain are sealed with a vinyldimethylsilyl group, 90 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 30,000 mPa · s, and hexamethyldisilazane 8 as a surface treatment agent. 40 parts by mass, 2 parts by mass of water, and 40 parts by mass of fumigant silica having a specific surface area of 300 m ² / g as a component (F) were mixed at room temperature for 30 minutes, and then mixed at 160 ° C. for 2 hours. The mixture was further cooled to 80 ° C. or lower, and then passed through three rolls once to obtain a silicone base A.

(D) Preparation of Radical Initiator A 50 parts by mass of dimethylpolysiloxane having both ends of the molecular chain sealed with a trimethylsilyl group as a plastic initiator and having a viscosity of 1,000 mPa · s at 25 ° C., and benzoyl peroxide 40 as a component (D). 10 parts by mass and 10 parts by mass of fumigant silica having a specific surface area of 200 m ² / g as a component (F) were mixed at room temperature for 30 minutes to obtain a radical initiator A.

(D) Preparation of Radical Initiator B As a plastic initiator, 48 parts by mass of dimethylpolysiloxane having both ends of the molecular chain sealed with a trimethylsilyl group and a viscosity of 500 mPa · s at 25 ° C., and di (4-methyl) as the component (D). 50 parts by mass of benzoyl) peroxide and 2 parts by mass of fumigant silica having a specific surface area of 200 m ² / g as a component (F) were mixed at room temperature for 30 minutes to obtain a radical initiator B.

[Example 1]
As a component (A), both ends of the molecular chain are sealed with a vinyldimethylsilyl group, and 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 10,000 mPa · s is a mixture of the components (A) and (F). 60 parts by mass of the silicone base A and both ends of the molecular chain as a component (B) are sealed with a trimethoxysilyl group, X in the above formula (1) is an ethylene group, R ¹ = R ² = a methyl group, and a. = 0, and 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 45,000 mPa · s was mixed at room temperature for 20 minutes. Then, 2.5 parts by mass of n-decyltrimethoxysilane as the component (C), 5 parts by mass of the radical initiator A as the component (D), and 0.1 of diisopropoxybis (ethylacetoacetate) titanium as the component (E). A mass portion and 2 parts by mass of diallyl maleate as a component (G) were mixed under normal pressure for 15 minutes and then mixed under reduced pressure conditions for 15 minutes to obtain Composition 1.

[Example 2]
As a component (A), both ends of the molecular chain are sealed with a vinyldimethylsilyl group, and 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 10,000 mPa · s is a mixture of the components (A) and (F). 60 parts by mass of the silicone base A and both ends of the molecular chain as a component (B) are sealed with a trimethoxysilyl group, X in the above formula (1) is an ethylene group, R ¹ = R ² = a methyl group, and a. = 0, and 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 45,000 mPa · s was mixed at room temperature for 20 minutes. Then, 2.5 parts by mass of 1,6-bis (trimethoxysilyl) hexane as the component (C), 5 parts by mass of the radical initiator A as the component (D), and diisopropoxybis (ethylacetoacetate) as the component (E). ) 0.1 part by mass of titanium and 2 parts by mass of diallyl maleate as a component (G) were mixed under normal pressure for 15 minutes and then mixed under reduced pressure for 15 minutes to obtain Composition 2.

[Example 3]
As a component (A), both ends of the molecular chain are sealed with a vinyldimethylsilyl group, and 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 10,000 mPa · s is a mixture of the components (A) and (F). 60 parts by mass of the silicone base A and both ends of the molecular chain as a component (B) are sealed with a trimethoxysilyl group, X in the above formula (1) is an ethylene group, R ¹ = R ² = a methyl group, and a. = 0, and 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 45,000 mPa · s was mixed at room temperature for 20 minutes. Then, 2.5 parts by mass of 1,6-bis (trimethoxysilyl) hexane as the component (C), 5 parts by mass of the radical initiator B as the component (D), and diisopropoxybis (ethylacetoacetate) as the component (E). ) 0.1 part by mass of titanium and 2 parts by mass of diallyl maleate as a component (G) were mixed under normal pressure for 15 minutes and then mixed under reduced pressure for 15 minutes to obtain Composition 3.

[Example 4]
As a component (A), both ends of the molecular chain are sealed with a vinyldimethylsilyl group, and 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 10,000 mPa · s is a mixture of the components (A) and (F). 60 parts by mass of the silicone base A and both ends of the molecular chain as a component (B) are sealed with a trimethoxysilyl group, X in the above formula (1) is an ethylene group, R ¹ = R ² = a methyl group, and a. = 0, and 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 45,000 mPa · s was mixed at room temperature for 20 minutes. Then, 2.5 parts by mass of 1,6-bis (trimethoxysilyl) hexane as the component (C), 5 parts by mass of the radical initiator A as the component (D), and diisopropoxybis (ethylacetoacetate) as the component (E). ) 0.1 part by mass of titanium and 1 part by mass of tetraallyl pyromellitic acid as a component (G) were mixed under normal pressure for 15 minutes and then mixed under reduced pressure for 15 minutes to obtain Composition 4.

[Example 5]
As a component (A), both ends of the molecular chain are sealed with a vinyldimethylsilyl group, and 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 10,000 mPa · s is a mixture of the components (A) and (F). 60 parts by mass of the silicone base A and both ends of the molecular chain as a component (B) are sealed with a trimethoxysilyl group, X in the above formula (1) is an oxygen atom, R ¹ = R ² = a methyl group, and a. = 0, and 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 23,000 mPa · s was mixed at room temperature for 20 minutes. Then, 2.5 parts by mass of 1,6-bis (trimethoxysilyl) hexane as the component (C), 5 parts by mass of the radical initiator A as the component (D), and diisopropoxybis (ethylacetoacetate) as the component (E). ) 0.1 part by mass of titanium and 2 parts by mass of diallyl maleate as a component (G) were mixed under normal pressure for 15 minutes and then mixed under reduced pressure for 15 minutes to obtain composition 5.

[Comparative Example 1]
The same component as described in Example 2 was blended to obtain composition 6 except that 1,6-bis (trimethoxysilyl) hexane as the component (C) was not added.

[Comparative Example 2]
The same component as described in Example 2 was blended except that titanium diisopropoxybis (ethylacetate acetate) as a component (E) was not added to obtain a composition 7.

[Comparative Example 3]
As a component (A), both ends of the molecular chain are sealed with a vinyldimethylsilyl group, 40 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 10,000 mPa · s, and a mixture of the components (A) and (F). 60 parts by mass of the silicone base A was mixed at room temperature for 20 minutes. Then, 2.5 parts by mass of 1,6-bis (trimethoxysilyl) hexane as the component (C), 5 parts by mass of the radical initiator A as the component (D), and diisopropoxybis (ethylacetoacetate) as the component (E). ) 0.1 part by mass of titanium and 2 parts by mass of diallyl maleate as a component (G) were mixed under normal pressure for 15 minutes and then mixed under reduced pressure for 15 minutes to obtain Composition 8.

The following characteristics were evaluated using the prepared compositions 1 to 8. The results are shown in Tables 1 and 2.

-Properties The properties of the prepared compositions 1 to 8 were visually confirmed.

-Curing characteristics The prepared compositions 1 to 8 are sandwiched between iron plates so that the thickness is about 3 mm, heated in a hydraulic molding machine (manufactured by Shoji Co., Ltd.) at 120 ° C for 10 minutes, and further 23 ° C / 50%. A cured product was obtained by leaving it in an RH atmosphere for 24 hours. The hardness (durometer type A), tensile strength (MPa), and elongation at cutting (%) of the obtained cured product were measured according to JIS K 6249. In each case, the third digit of the measured value was rounded off to two significant figures.

-Confirmation of hardness change rate The hardness (durometer type A) after being heat-cured for 10 minutes under the above 120 ° C. condition is left for 1 day (24 hours) in a room temperature environment of H ₁ and an additional 23 ° C./50% RH. The hardness (durometer type A) after the above was defined as H ₂ , and the ratio of H ₂ to H ₁ (H ₂ / H ₁ ) was calculated. For each numerical value, the fourth digit of the calculated value was rounded off to three significant figures.

-Surface curability The prepared compositions 1 to 8 were placed in a glass petri dish having a diameter of 10 mm and a height of 13 mm, and left in a dryer at 120 ° C. for 10 minutes. After 10 minutes, the glass petri dish containing the compositions 1 to 8 was taken out from the dryer and left in a 23 ° C./50% RH atmosphere for 24 hours. After 24 hours, the surface tack of the cured compositions 1 to 8 was confirmed. The index of surface tack is as follows.
◯: No tackiness on the surface of the cured product ×: The surface of the cured product is not cured at all

-The adhesive compositions 1 to 8 are sandwiched between the following adherends so as to have a thickness of 2 mm, left in a dryer at 120 ° C. for 20 minutes, and further left in a 23 ° C./50% RH atmosphere for 24 hours. The compositions 1-8 were completely cured. Using the obtained test piece, the shear adhesive force (MPa) was measured according to JIS K 6249. In each case, the third digit of the measured value was rounded off to two significant figures. The coagulation fracture rate (%) was also measured.
Substrate: Aluminum, Polybutylene terephthalate (PBT), Polyphenylene sulfide (PPS)

-Storage stability The compositions 1 to 8 were placed in a sealable container and left at room temperature for 30 days to confirm the stability (presence or absence of change) of the composition, and the one without change was regarded as good.

In Examples 1 to 5 (Compositions 1 to 5), the curing properties, surface curability, adhesiveness, and storage stability were good.
Although Comparative Example 1 (Composition 6) had good curing properties, surface curability, and adhesiveness, rapid thickening was confirmed only by placing it in a sealable container and leaving it at room temperature for 1 day.
Comparative Example 2 (Composition 7) had good curability, adhesiveness, and storage stability, but did not exhibit surface curability at all. It is probable that room temperature curing due to humidity did not proceed because the component (E) was not added.
Comparative Example 3 (Composition 8) had good curability, adhesiveness, and storage stability, but did not exhibit surface curability. It is probable that room temperature curing due to humidity did not proceed because the organopolysiloxane component (B) was not added.

As described above, good curing characteristics are achieved by performing thermal radical curing at 120 ° C. for 10 to 20 minutes as the first curing, and room temperature curing at 23 ° C./50% RH atmosphere for 24 hours as the second curing. It can be seen that surface curability and adhesiveness are exhibited.

The following shows examples and comparative examples that are considered to be useful for coating and potting applications.

[Example 6]
As a component (A), both ends of the molecular chain are sealed with a vinyldimethylsilyl group, 70 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 400 mPa · s, and the above silicone base which is a mixture of the components (A) and (F). 10 parts by mass of A and both ends of the molecular chain as a component (B) are sealed with a trimethoxysilyl group, X in the above formula (1) is an ethylene group, R ¹ = R ² = methyl group, and a = 0. 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 45,000 mPa · s was mixed at room temperature for 20 minutes. Then, 2 parts by mass of 1,6-bis (trimethoxysilyl) hexane as the component (C), 5 parts by mass of the radical initiator A as the component (D), and diisopropoxybis (ethylacetoacetate) titanium as the component (E). 0.5 parts by mass, 0.1 part by mass of tetra- (2-ethylhexyl) titanate, and 4 parts by mass of diallyl maleate as a component (G) are mixed for 15 minutes under normal pressure, and then mixed for 15 minutes under reduced pressure conditions. , Composition 9 was obtained.

[Example 7]
As a component (A), both ends of the molecular chain are sealed with a vinyldimethylsilyl group, 70 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 400 mPa · s, and the above silicone base which is a mixture of the components (A) and (F). 10 parts by mass of A and both ends of the molecular chain as a component (B) are sealed with a trimethoxysilyl group, X in the above formula (1) is an ethylene group, R ¹ = R ² = methyl group, and a = 0. 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 45,000 mPa · s was mixed at room temperature for 20 minutes. Then, 2 parts by mass of 1,6-bis (trimethoxysilyl) hexane as the component (C), 5 parts by mass of the radical initiator A as the component (D), and diisopropoxybis (ethylacetoacetate) titanium as the component (E). Mix 0.5 parts by mass, 0.1 part by mass of tetra- (2-ethylhexyl) titanate, and 1 part by mass of tetraallyl pyromellitic acid as a component (G) under normal pressure for 15 minutes, and then mix under reduced pressure for 15 minutes. And the composition 10 was obtained.

[Example 8]
As a component (A), both ends of the molecular chain are sealed with a vinyldimethylsilyl group, 70 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 400 mPa · s, and the above silicone base which is a mixture of the components (A) and (F). 10 parts by mass of A and both ends of the molecular chain as a component (B) are sealed with a trimethoxysilyl group, X in the above formula (1) is an ethylene group, R ¹ = R ² = methyl group, and a = 0. 20 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of 45,000 mPa · s was mixed at room temperature for 20 minutes. Then, 2 parts by mass of n-decyltrimethoxysilane as the component (C), 5 parts by mass of the radical initiator A as the component (D), and 0.5 parts by mass of diisopropoxybis (ethylacetacetate) titanium as the component (E). , 0.1 part by mass of tetra- (2-ethylhexyl) titanate and 1 part by mass of tetraallyl pyromellitic acid as a component (G) are mixed under normal pressure for 15 minutes and then mixed under reduced pressure for 15 minutes to form composition 11. Got

[Comparative Example 4]
The same component as described in Example 6 was blended except that 1,6-bis (trimethoxysilyl) hexane as the component (C) was not added to obtain a composition 12.

[Comparative Example 5]
The same components as described in Example 6 were blended to obtain the composition 13 except that the components (E), diisopropoxybis (ethylacetoacetate) titanium and tetra- (2-ethylhexyl) titanate, were not added. rice field.

The following characteristics were evaluated using the prepared compositions 9 to 13. The results are shown in Table 3.

-Initial Viscosity The prepared compositions 9 to 13 were used to measure the viscosity in a 23 ° C./50% RH environment in accordance with JIS K 6249.

-Curing characteristics The prepared compositions 9 to 13 are sandwiched between iron plates so that the thickness is about 3 mm, heated in a hydraulic molding machine (manufactured by Shoji Co., Ltd.) at 120 ° C for 15 minutes, and further 23 ° C / 50%. A cured product was obtained by leaving it in an RH atmosphere for 24 hours. The hardness (durometer type A), tensile strength (MPa), and elongation at cutting (%) of the obtained cured product were measured according to JIS K 6249. In each case, the third digit of the measured value was rounded off to two significant figures.

-Confirmation of hardness change rate The hardness (durometer type A) after being heat-cured for 15 minutes under the above 120 ° C. condition is left for 1 day (24 hours) in a room temperature environment of H ₁ and an additional 23 ° C./50% RH. The hardness (durometer type A) after the above was defined as H ₂ , and the ratio of H ₂ to H ₁ (H ₂ / H ₁ ) was calculated. For each numerical value, the fourth digit of the calculated value was rounded off to three significant figures.

-Surface curability The prepared compositions 9 to 13 were placed in a glass petri dish having a diameter of 10 mm and a height of 13 mm, and left in a dryer at 120 ° C. for 20 minutes. After 20 minutes, the glass petri dish containing the compositions 9 to 13 was taken out from the dryer and left in a 23 ° C./50% RH atmosphere for 24 hours. After 24 hours, the surface tack of the cured compositions 9 to 13 was confirmed by touch. The indexes of surface curability (presence or absence of surface tack) are as follows.
◯: There is no tackiness on the surface of the cured product (no surface tackiness)
×: The surface of the cured product is not cured at all (there is surface tack).

-Applying the adhesive compositions 9 to 13 to a Fr-4 substrate (printed circuit board, Flame Retardant Type 4) so as to have a thickness of 1 mm, leaving it in a dryer at 120 ° C. for 20 minutes, and further 23 ° C./50%. The compositions 9 to 13 were completely cured by leaving them in an RH atmosphere for 24 hours. The obtained test piece was evaluated by the following index as to whether or not the cured product of the compositions 9 to 13 was adhered to the Fr-4 substrate.
◯: The cured product of the composition is adhered to Fr-4 (adhesion is good).
X: The cured product of the composition is peeled off from Fr-4 (poor adhesion).

-Storage stability The compositions 9 to 13 were placed in a sealable container and left at room temperature for 30 days to confirm the stability (presence or absence of change) of the composition, and the one without change was regarded as good.

In Examples 6 to 8 (compositions 9 to 11), the curing characteristics, surface curability, adhesiveness, and storage stability were good. In addition, it is a low-viscosity composition considered to be useful for coating and potting.
Comparative Example 4 (composition 12) had good curability, surface curability, and adhesiveness. In addition, although the adhesiveness was good, rapid thickening was confirmed only by placing the bottle in a sealable bottle and leaving it at room temperature for 3 days. The viscosity after standing at room temperature for 3 days was 5,600 mPa · s, suggesting that the composition lacks storage stability.
Comparative Example 5 (Composition 13) had good curability, adhesiveness, and storage stability, but did not exhibit surface curability at all. It is probable that room temperature curing did not proceed due to humidity because the organic titanium compound (E) was not added.

The composition used in the above examples is characterized in that it is radically cured by heat as the first curing and then cured at room temperature and humidity as the second curing. Normally, only the first curing using thermal radicals causes the portion in contact with oxygen to be inhibited from curing and becomes uncured. By incorporating the second curing, the uncured portion is gradually cured at room temperature so that the uncured portion no longer exists. Another feature is that there is little change in hardness after the second curing.

It is considered that the heat radical curable organopolysiloxane composition of the present invention is most suitable for a sealing agent, a coating agent, and a potting agent for automobile-related products having a short tact time.
Further, since the organopolysiloxane composition of the present invention that can be thermally radically cured uses a versatile organopolysiloxane, it has a great cost advantage and is a polymer having an acrylic group that is usually used in thermal radical curing. It is considered that one of the merits is that the odor is less than that of the above.

Claims

(A) Organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass,
(B) The following general formula (1)

(In the formula, R 1 is an independently unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, n is an integer of 10 or more, and R 2 is independently non-substituted with 1 to 6 carbon atoms. It is a substituted or substituted monovalent hydrocarbon group, X is an oxygen atom or an alkylene group having 1 to 4 carbon atoms, and a is 0 or 1 independently for each silicon atom to be bonded.)
Organopolysiloxane indicated by: 5-80 parts by mass,
(C) A (organo) silane compound having 3 or more hydrolyzable groups in one molecule and / or a partially hydrolyzed condensate thereof: 0.1 to 30% by mass with respect to the content of the component (B). amount,
(D) Radical initiator: 0.1 to 20 parts by mass,
(E) Moisture curing initiator: 0.01 to 10% by mass with respect to the content of the component (B),
(F) Inorganic filler: An organopolysiloxane composition containing an amount of 1 to 500% by mass based on the total amount of the components (A) and (B), and 80 to 150 as the primary curing. The hardness (H 1 ) of the cured product obtained by heat-curing at ° C. for 5 to 60 minutes, and as the secondary curing, the cured product is further moistened for 1 day in an environment of a temperature of 23 ° C. and a humidity of 50% RH. Regarding the hardness (H 2 ) of the cured product after curing, a thermal radical that gives the cured product in which the ratio of H 2 to H 1 (H 2 / H 1 ) is 1.00 to 1.20. Curable organopolysiloxane composition.
The thermally radical curable organopolysiloxane according to claim 1, further comprising (G) 1 to 20 parts by mass of an organic compound having two or more allyl groups in one molecule with respect to 100 parts by mass of the component (A). Composition.
The component (C) is organotrialkoxysilane, tetraalkoxysilane, tetraalkoxydisilane compound, tetraalkoxytrisilane compound, hexaalkoxydisilane compound, hexaalkoxytrisilane compound, (organo) acetoxysilane, (organo) isopropenoxysilane. The thermoradical curable organopolysiloxane composition according to claim 1 or 2, which is one or more selected from the group consisting of (organo) ketooxymsilane.
The thermally radical curable organopolysiloxane composition according to any one of claims 1 to 3, wherein the component (E) is an organic titanium compound or an organic tin compound.
An article bonded, coated or potted with a cured product of the organopolysiloxane composition according to any one of claims 1 to 4.
The thermally radical curable organopolysiloxane composition according to any one of claims 1 to 4 can be thermally radically cured, which comprises a step of thermally radically curing the organopolysiloxane composition at 80 to 150 ° C. and then condensing curing at room temperature. A method for producing a cured product of an organopolysiloxane composition.