JPH07292254A - Room-temperature-curing organopolysiloxane composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which can be cured with moisture to form a silicone rubber excellent in heat resistance in a region of high temperatures by mixing a specified diorganopolysiloxane with a specified organosilicon compound, a curing catalyst and a fine yellow iron oxide powder. CONSTITUTION:This composition comprises 100 pts.wt. diorganopolysiloxane having at least two Si-bonded hydroxyl groups or Si-bonded alkoxyl groups and having a viscosity of 20-1000000cP at 25 deg.C [desirably the one represented by the formula (wherein R<1> is a monovalent hydrocarbon group; R<2> is OH or an alkoxy; R<3> is O or a bivalent hydrocarbon group; (a) is 1, 2 or 3; and (n) is a number to give the above viscosity to the compound], 0.1-25 pts.wt. organosilicon compound having at least two Si-bonded hydrolyzable groups in the molecule, 0.01-10 pts.wt. curing catalyst and 0.1-50 pts.wt. fine yellow iron oxide powder. The composition can cure with moisture to give a silicone rubber having excellent heat resistance in a region of high temperatures.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room temperature curable organopolysiloxane composition, and more particularly to a room temperature curable organopolysiloxane which is cured by moisture to form a silicone rubber having excellent heat resistance in a high temperature range. It relates to a composition.

[0002]

2. Description of the Related Art Room-temperature-curable organopolysiloxane compositions that cure at room temperature due to moisture in the air are suitable for use as sealing agents, adhesives, and coating agents for electric and electronic devices. However, there is a problem that the heat resistance of the silicone rubber obtained by curing the composition is low and the use of the composition is limited.

Various room-temperature-curable organopolysiloxane compositions which form silicone rubbers having excellent heat resistance have been investigated. For example, diorganopolysiloxanes whose both molecular chain ends are blocked with silicon-bonded hydroxyl groups,
Room temperature-curable organopolysiloxane composition comprising organosilane having a silicon atom-bonded hydrolyzable group and iron oxide ferrite fine powder in which a metal oxide is solid-dissolved (see JP-A-52-45655), molecular chain Room temperature-curable organopolysiloxane composition comprising dimethylpolysiloxane whose both ends are blocked by silicon-bonded hydroxyl groups, alkoxysilane, organic tin compound, and iron oxide fine powder (red iron oxide) (see JP-A-60-8361). , An organopolysiloxane having a hydroxyl group in the molecule, an organosilicon compound having a hydrolyzable group of a silicon atom bond, a curing catalyst, carbon black and iron oxide (α-Fe
_A room-temperature-curable organopolysiloxane composition composed of ₂ O ₃ ) fine powder (see JP-A-62-127348) has been proposed.

[0004]

However, Japanese Patent Laid-Open No. 52-
45655, JP-A-60-8361 and JP-A-6
The room temperature-curable organopolysiloxane composition proposed by JP-A-2-127348 has sufficient heat resistance at a temperature of less than 280 ° C. of the silicone rubber obtained by curing the composition, but the silicone rubber having a temperature of 280 ° C. or higher is obtained. There is a problem that the heat resistance in the high temperature region is insufficient.

The present inventors have arrived at the present invention as a result of extensive studies to solve the above problems.

That is, an object of the present invention is to provide a room temperature curable organopolysiloxane composition which is cured by moisture to form a silicone rubber having excellent heat resistance in a high temperature range.

[0007]

Means for Solving the Problem and Its Action The present invention provides (A) a viscosity at 25 ° C. of 20 to 1,000,000 centipoise, and at least two silicon atom-bonded hydroxyl groups or silicon atoms in one molecule. 100 parts by weight of diorganopolysiloxane having an atom-bonded alkoxy group, (B) 0.1 to 25 parts by weight of an organosilicon compound having at least two hydrolyzable groups having a silicon atom bond in one molecule, (C) A room temperature curable organopolysiloxane composition comprising 0.01 to 10 parts by weight of a curing catalyst and 0.1 to 50 parts by weight of (D) yellow iron oxide fine powder.

The room temperature curable organopolysiloxane composition of the present invention will be described in detail.

The room-temperature-curable organopolysiloxane composition of the present invention is a composition that is cured at room temperature by moisture in the air to form a silicone rubber, and is, for example, an alcohol elimination curing type or an oxime compound elimination curing type. , Acetic acid elimination-curing type, ketone elimination-curing type, amine compound elimination-curing type, amide compound elimination-curing type and hydroxyamine compound elimination-curing type room temperature curable organopolysiloxane composition.

The component (A), which is the main component of the present composition, has a viscosity at 25 ° C. of 20 to 1,000,000.
It is a centipoise and is a diorganopolysiloxane having at least two silicon atom-bonded hydroxyl groups or silicon atom-bonded alkoxy groups in one molecule. Specific examples of the silicon atom-bonded alkoxy group in the component (A) include a methoxy group, an ethoxy group, a propoxy group and a butoxy group, and since the curability of the resulting composition is good,
A methoxy group is preferred. The bonding position of the silicon atom-bonded hydroxyl group or the silicon atom-bonded alkoxy group in the component (A) is not particularly limited, and examples thereof include a molecular chain terminal and / or a molecular chain side chain, and the curability of the resulting composition is good. Therefore, the end of the molecular chain is preferable. Specific examples of the silicon atom-bonded organic group other than the silicon atom-bonded alkoxy group in the component (A) include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group and octyl group. Alkyl group; cycloalkyl group such as cyclopentyl group, cyclohexyl group; alkenyl group such as vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group; phenyl group, tolyl group, xylyl group, naphthyl group, etc. Aryl groups; aralkyl groups such as benzyl group, phenethyl group, phenylpropyl group; halo-substituted alkyl groups such as chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, etc., and particularly methyl group A phenyl group is preferred.

The component (A) is linear or partially branched and preferably has the general formula:

[Chemical 1] (In the formula, R ¹ is a monovalent hydrocarbon group, R ² is a hydroxyl group or an alkoxy group, R ³ is an oxygen atom or a divalent hydrocarbon group, a is 1, 2 or 3, and n Is a number such that the viscosity of the diorganopolysiloxane represented by the above formula at 25 ° C. is 20 to 1,000,000 centipoise.).
In the above formula, R ¹ is a monovalent hydrocarbon group, specifically, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group; a cyclopentyl group. , Cycloalkyl groups such as cyclohexyl groups; alkenyl groups such as vinyl groups, allyl groups, butenyl groups, pentenyl groups, hexenyl groups; aryl groups such as phenyl groups, tolyl groups, xylyl groups, naphthyl groups; benzyl groups, phenethyl groups, Aralkyl groups such as phenylpropyl group; chloromethyl group, 3-chloropropyl group, 3,
Examples thereof include halo-substituted alkyl groups such as 3,3-trifluoropropyl group, and methyl group and phenyl group are particularly preferable.
Further, in the above formula, R ² is a hydroxyl group or an alkoxy group, and specific examples of the alkoxy group of R ² include a methoxy group, an ethoxy group, a propoxy group and a butoxy group, and a methoxy group is particularly preferable. Further, in the above formula, R ³ is an oxygen atom or a divalent hydrocarbon group, and specific examples of the divalent hydrocarbon group of R ³ include a methylmethylene group, an ethylene group, a propylene group, a butylene group and a hexenylene group. And an arylalkylene group such as a phenylethylene group and a phenylpropylene group, and an oxygen atom or an ethylene group or a propylene group is particularly preferable as R ³ . In the above formula, a is 1, 2 or 3,
n is the viscosity of the component (A) at 25 ° C. of 20 to 1,000.
The number is within the range of 10,000 centipoise.

The viscosity of the component (A) at 25 ° C. is 20 to
It is necessary to be within the range of 1,000,000 centipoise, and particularly preferably within the range of 100 to 500,000 centipoise. This is (A) component 2
This is because when the viscosity at 5 ° C. is less than 20 centipoise, the physical properties of the obtained silicone rubber, such as flexibility and elongation, deteriorate, and this is 1,000,00.
This is because if it exceeds 0 centipoise, the workability of the obtained composition deteriorates.

In order to accelerate the curing rate of the room temperature curable organopolysiloxane composition of the present invention, as the component (A),
It is preferable to use a diorganopolysiloxane having at least two silicon atom-bonded alkoxy groups in one molecule, and further, a diorganopolysiloxane in which both ends of the molecular chain are blocked with a trialkoxysilylalkyl group or a trialkoxysiloxy group. Preference is given to using siloxanes.

As a method for preparing a diorganopolysiloxane whose both molecular chain ends are blocked with trialkoxysiloxy groups, for example, a diorganopolysiloxane whose both molecular chain ends are blocked with silicon-bonded hydroxyl groups and a tetraalkoxysilane are used. Examples of the method for preparing a diorganopolysiloxane in which both molecular chain ends are blocked with trialkoxysilylalkyl groups include, for example, a method in which both molecular chain ends are silicon. A method for carrying out an addition reaction of a diorganopolysiloxane blocked with an atom-bonded alkenyl group and a trialkoxysilane in the presence of a catalyst for a hydrosilylation reaction, and a diorganopolysiloxane having both molecular chain ends blocked with silicon atom-bonded hydrogen atoms. Existence of catalyst for hydrosilylation of alkenyltrialkoxysilane In a method of adding reaction.

The component (B) is an organosilicon compound having at least two hydrolyzable groups having a silicon atom in each molecule, which acts as a curing agent for the composition. Specific examples of the hydrolyzable group having a silicon atom bond in the component (B) include an alkoxy group, an oxime group, an alkenoxy group, an acetoxy group, an amino group, an amido group and an aminoxy group. Specific examples of the organosilicon compound as the component (B) include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetra (2-chloroethoxy) silane, methylcellosolve orthosilicate, and methyltrioxide. Methoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, octadecyltrimethoxysilane, propyltris (4-chlorobutoxy) silane Alkoxysilanes such as methyltris (methoxyethoxy) silane, diphenyldimethoxysilane and dimethyldimethoxysilane; alkoxysilanes such as ethylpolysilicate and dimethyltetramethoxydisiloxane. Sun; tetra (methyl ethyl ketoxime) silane, tetra (dimethyl ketoxime) silane, methyl tris (methyl ethyl ketoxime) silane, methyltris (diethyl ketoxime)
Silane, vinyltris (dimethylketoxime) silane, methyltris (acetoneoxime) silane, vinyltris (dimethylketoxime) silane, phenyltris (dimethylketoxime) silane, phenyltris (dimethylketoxime) silane, dimethylbis (dimethylketoxime) Silanes, oxime silanes such as dimethylbis (acetoxime) dimethylsilane; alkenoxysilanes such as methyltris (propenyloxy) silane, vinyltris (butenyloxy) silane, phenyltris (propenyloxy) silane, dimethylbis (propenonyloxy) silane Methyltriacetoxysilane, methyltrioctanoyloxysilane, methyltribenzoyloxysilane, triacetoxybutoxysilane, phenyltriaceto Acetoxysilanes such as silane, vinyltriacetoxysilane, dimethyldiacetoxysilane, methylvinyldiacetoxysilane, di-t-butyldiacetoxysilane, diphenyldiacetoxysilane; methyltris (dimethylamino) silane, vinyltris (dimethylamino) silane, Vinyl Tris (N-
Aminosilane such as butylamino) silane, phenyltris (dimethylamino) silane, methyltris (cyclohexylamino) silane, dimethyl-bis (diethylamino) silane, diphenyl-bis (diethylamino) silane, methylphenyl-bis (diethylamino) silane;
Methyltris (N-methylacetamido) silane, methyltris (N-butylacetamido) silane, methyltris (N-cyclohexylacetamido) silane, dimethylbis (N-methylacetamido) silane, dimethylbis (N-ethylacetamido) silane, methylvinylbis Amidosilanes such as (N-methylacetamido) silane; aminoxysilanes such as methyltris (N, N-diethylaminoxy) silane; and siloxanes obtained by partially hydrolyzing and condensing a part of these silanes or siloxanes. May be used alone or as a mixture of two or more kinds.

As component (A), at least 2 in one molecule
When a diorganopolysiloxane having a silicon atom-bonded hydroxyl group is used, it is preferable to use the above-mentioned alkoxysilane or alkoxysiloxane or a partial hydrolyzate thereof as the component (B). It is a curable room temperature curable organopolysiloxane composition. When the component (A) is a diorganopolysiloxane having at least two silicon atom-bonded hydroxyl groups in one molecule, the component (B) is an oxime silane or a partial hydrolyzate thereof. Is preferred, and the resulting composition is a room temperature-curable organopolysiloxane composition of the oxime compound elimination curing type. When the component (A) is a diorganopolysiloxane having at least two silicon-bonded hydroxyl groups in one molecule, the component (B) is the acetoxysilane or a partial hydrolyzate thereof. Is preferred, and the resulting composition is an acetic acid elimination curing type room temperature curable organopolysiloxane composition. When a diorganopolysiloxane having at least two silicon-bonded hydroxyl groups in one molecule is used as the component (A), the alkenoxysilane or a partial hydrolyzate thereof is used as the component (B). It is preferably used, and the resulting composition is a ketone elimination curing type room temperature curable organopolysiloxane composition. When the component (A) is a diorganopolysiloxane having at least two silicon atom-bonded hydroxyl groups in one molecule, the component (B) is preferably the aminosilane or a partial hydrolyzate thereof. Preferably, the resulting composition is an amine compound elimination curing type room temperature curable organopolysiloxane composition. Further, as the component (A), at least 2 in one molecule.
When using a diorganopolysiloxane having silicon atom-bonded hydroxyl groups, it is preferable to use the above-mentioned amide silane or a partial hydrolyzate thereof as the component (B), and the resulting composition is an amide compound elimination-curing type. The room temperature curable organopolysiloxane composition is obtained. Also, (A)
When a diorganopolysiloxane having at least two silicon atom-bonded hydroxyl groups in one molecule is used as the component, it is preferable to use the above aminoxysilane or a partial hydrolyzate thereof as the component (B). The composition obtained is a room temperature-curable organopolysiloxane composition of a hydroxyamine compound elimination curing type. Furthermore, (A)
When a diorganopolysiloxane having at least two silicon atom-bonded alkoxy groups in one molecule is used as the component, the above-mentioned alkoxysilane or alkoxysiloxane or a partial hydrolyzate thereof is used as the component (B). Preferably, the resulting composition is an alcohol elimination curing type room temperature curable organopolysiloxane composition.

The blending amount of the component (B) is required to be in the range of 0.1 to 25 parts by weight, particularly 0.5 to 10 parts by weight, relative to 100 parts by weight of the component (A). Is preferred. This is based on 100 parts by weight of component (A) (B)
This is because if the amount of the component is less than 0.1 parts by weight, the resulting composition will not be sufficiently cured, or thickening or gelation will easily occur during storage under exclusion of moisture. If it exceeds, the curing rate of the obtained composition is remarkably slowed and it is uneconomical.

Component (C) is a curing catalyst for accelerating the curing of the composition, and is not particularly limited as long as it is a curing catalyst used in a condensation reaction. Specific examples of the curing catalyst for the component (C) include di-n-butyltin diacetate and di-n-butyltin diacetate.
Organotin such as n-butyltin di-2-ethylhexoate, n-butyltin tri-2-ethylhexoate, di-n-butyltin dilaurate, di-n-butyltin dioctoate, stannas octoate Compounds: tetra-n-butyl titanate, tetraisopropyl titanate, tetra-
Organic titanate ester compounds such as 2-ethylhexyl titanate and ethylene glycol titanate; diisopropoxybis (acetylacetone) titanium, diisopropoxybis (ethylacetoacetate) titanium, diisopropoxybis (methylacetoacetate) titanium, dimethoxybis ( Organic titanium complex compounds such as titanium acetoacetate) and titanium dibutoxybis (ethyl acetoacetate); stannous caprylate, tin naphthenate, cobalt naphthenate, iron naphthenate, tin oleate, zinc naphthenate, zinc stearate, Titanium naphthenate, tin octoate, iron octoate, lead octoate, etc. tin, titanium, zirconium, iron,
Examples thereof include organic acid salts of metals such as antimony, cobalt, bismuth, manganese, and lead.

When a diorganopolysiloxane having at least two silicon-bonded hydroxyl groups in one molecule is used as the component (A), an organotin compound or an organic acid salt of tin is used as the component (C). Is preferably used.
When a diorganopolysiloxane having at least two silicon-bonded alkoxy groups in one molecule is used as the component (A), an organic titanate ester, an organic titanium complex compound or titanium is used as the component (C). It is preferable to use the organic acid salt of.

The blending amount of the component (C) must be within the range of 0.01 to 10 parts by weight, especially within the range of 0.1 to 5 parts by weight, relative to 100 parts by weight of the component (A). Is preferred. This is (C) for 100 parts by weight of component (A).
This is because if the amount of the component is less than 0.01 parts by weight, the curing rate of the obtained composition will be significantly slowed down.
This is because if it exceeds 0 parts by weight, the storage stability of the resulting composition under the exclusion of moisture is significantly deteriorated.

The component (D) is yellow iron oxide fine powder, which is a characteristic component of the present composition, and is a component which imparts excellent heat resistance to the silicone rubber obtained by curing the composition.
The component (D) has the formula: α-FeO · OH or α-FeO
It is a fine powder of iron oxyhydroxide represented by (OH) · mH ₂ O (in the formula, m is a positive number), and its shape is needle-like belonging to the orthorhombic form. The particle size of the component (D) is not particularly limited, but the average particle size thereof is 50 because the workability of the resulting composition and the heat resistance of the silicone rubber are excellent.
It is preferably a fine powder having a size of less than μm, and further 325
It is preferable that the powder is a fine powder having a sieve residue of 1% by weight or less due to a mesh (opening of mesh = about 44 μm). Component (D) is obtained by directly using a commercially available thermoplastic organic resin or an inorganic pigment for paints, or by heating these yellow iron oxide fine powders to remove a part of the water of crystallization. It is also possible to use a slightly yellowish yellow iron oxide fine powder. The method for preparing the component (D) is not particularly limited. For example, iron is added to a dilute aqueous solution of ferrous sulfate, and the solution is heated to 50 to 60 ° C. in the presence of suitable crystal-forming nuclei while blowing air. However, a method of preparing by precipitating on crystal-forming nuclei by hydrolysis reaction, a method of preparing a precipitate formed by adding an alkali to an aqueous solution of ferric salt by hydrothermal treatment in an autoclave at a pH of 11 or more, are exemplified. To be Further, by using, as the component (D), yellow iron oxide fine powder in which aluminate such as aluminate or sodium aluminate or potassium aluminate is dissolved, the heat resistance of the obtained silicone rubber can be further improved. it can. A method for preparing a yellow iron oxide fine powder in which aluminic acid or an aluminate is solid-dissolved is not particularly limited, and, for example, yellow iron oxide is added to an aqueous ferric chloride solution,
100 after adding aluminate or aluminate
The method of preparing by performing hydrothermal treatment in the range of ˜250 ° C. may be mentioned.

The blending amount of the component (D) must be within the range of 0.1 to 50 parts by weight, and particularly within the range of 1 to 20 parts by weight, relative to 100 parts by weight of the component (A). It is preferable. This is because when the amount of the component (D) is less than 0.1 parts by weight with respect to 100 parts by weight of the component (A), the resulting silicone rubber has insufficient heat resistance in a high temperature range. This is because if the amount exceeds 50 parts by weight, the handling workability of the obtained composition deteriorates.

Further, the room temperature-curable organopolysiloxane composition of the present invention is (E) in order to impart heat resistance in a wide temperature range to the silicone rubber obtained by curing the same.
It is preferable to add the red iron oxide fine powder as a component.
The component (E) is represented by the formula: Fe ₂ O ₃ and is generally commercially available as red iron oxide. Although the particle size of the component (E) is not particularly limited, it is preferably a fine powder having an average particle size of 50 μm or less because the composition obtained has excellent workability in handling and the heat resistance of the silicone rubber is further preferably 325. It is preferable that the fine powder has a sieving residue of 1% by weight or less due to a mesh (opening of mesh = about 44 μm). Further, by using a yellow iron oxide fine powder in which aluminic acid or an aluminate is solid-dissolved as the component (D) and combining this with the component (E), the obtained silicone rubber is provided with further excellent heat resistance. be able to.

When the component (E) is blended with the room temperature curable organopolysiloxane composition of the present invention, the amount of the component (E) blended is 0.1 to 50 parts by weight per 100 parts by weight of the component (A). It is preferably within the range of 1 part by weight, and particularly preferably within the range of 1 to 20 parts by weight. This is component (A) 10
This is because if the amount of component (E) is less than 0.1 parts by weight relative to 0 parts by weight, the heat resistance of the resulting silicone rubber in a wide temperature range will be insufficient, and if it exceeds 50 parts by weight. This is because the workability of the obtained composition is reduced.

The room temperature-curable organopolysiloxane composition of the present invention can be prepared by uniformly mixing the components (A) to (D) and, if necessary, the component (E). In the room temperature-curable organopolysiloxane composition of the present invention, as components other than the above, for example, in order to improve the physical properties of the obtained silicone rubber, dry silica, wet silica, calcined silica, ground quartz, calcium carbonate, fumed Inorganic fillers such as titanium dioxide, diatomaceous earth, aluminum hydroxide, aluminum oxide, magnesium carbonate, magnesium oxide, zinc oxide, zinc carbonate and fine powder mica, and the surface of these inorganic fillers is treated with an organosilazane compound, an organocyclosiloxane. Compounds, organochlorosilane compounds, organoalkoxysilane compounds, inorganic fillers hydrophobized with low molecular weight linear siloxanes, organic solvents, fungicides, flame retardants, plasticizers, thixotropic agents, adhesion promoters , Curing accelerator, pigment, black iron oxide, car It can be formulated heat stabilizers such as down black.

The room-temperature-curable organopolysiloxane composition of the present invention can be stored for a long time in the absence of moisture, and can be cured by humidity at room temperature to have excellent heat resistance in a high temperature range. To form
The composition is used as a sealing agent for electric and electronic devices, an adhesive,
It can be used as a coating agent, and in addition, it requires a stable heat resistance in the high temperature range. Sheath heater sealing agent, iron sealing agent, oven range window frame sealing agent,
It can be used as a joint sealant for chimneys.

[0027]

EXAMPLES The room temperature curable organopolysiloxane composition of the present invention will be described in detail with reference to Examples. In the examples, the viscosity is a value measured at 25 ° C. The physical properties of the silicone rubber obtained by curing the room temperature curable organopolysiloxane composition were measured by the following methods.

Initial physical properties of silicone rubber: The room temperature curable organopolysiloxane composition was allowed to stand for 1 week at 20 ° C. and 55% RH to prepare a silicone rubber sheet having a thickness of 1 mm. This silicone rubber sheet is JIS K
Cut out as a No. 3 dumbbell specified in 6301. The physical properties (hardness, tensile strength, elongation) of this silicone rubber dumbbell were measured according to the method specified in JIS K6301.

Physical properties of silicone rubber after heat resistance test: The silicone rubber dumbbell prepared by the above method was allowed to stand for 10 days at 340 ° C., and the physical properties of this silicone rubber dumbbell were measured by the same methods as described above.

[Example 1] 100 parts by weight of dimethylpolysiloxane having a viscosity of 3,000 centipoise and having both ends of the molecular chain blocked with trimethoxysiloxy groups, BET
10 parts by weight of dry silica fine powder having a specific surface area of 110 m ² / g and having its surface hydrophobized with hexamethyldisilazane, and a sieving residue of 325 mesh of 0.0
After mixing 5 parts by weight of 2% by weight of yellow iron oxide fine powder (manufactured by Nippon Benji Industry Co., Ltd .; trade name NYB-40) at room temperature for 30 minutes until uniform, further under reduced pressure of 40 mmHg,
Heated to 150 ° C. and mixed. Then, this was cooled to room temperature, 2 parts by weight of methyltrimethoxysilane and 0.5 part by weight of diisopropoxy-bis (ethyl acetoacetate) titanium were added thereto under moisture exclusion, and then uniformly mixed, A room temperature curable organopolysiloxane composition of the present invention was prepared. The properties of the silicone rubber obtained by curing this room temperature curable organopolysiloxane composition were measured after the initial stage and after the heat resistance test, and the results are shown in Table 1.

Example 2 100 parts by weight of dimethylpolysiloxane having a viscosity of 3,000 centipoise and having both ends of the molecular chain blocked with trimethoxysiloxy groups, BET
5 parts by weight of dry silica fine powder having a specific surface area of 110 m ² / g and hydrophobizing the surface with hexamethyldisilazane, and a sieving residue of 325 mesh of 0.02
After mixing 10 parts by weight of yellow iron oxide fine powder (manufactured by Nippon Beni Kogyo Co., Ltd .; trade name NYB-40) in an amount of 30% by weight until uniform at room temperature for 30 minutes, further under reduced pressure of 40 mmHg,
Heated to 150 ° C. and mixed. Then, this was cooled to room temperature, 2 parts by weight of methyltrimethoxysilane and 0.5 part by weight of diisopropoxy-bis (ethyl acetoacetate) titanium were added thereto under moisture exclusion, and then uniformly mixed, A room temperature curable organopolysiloxane composition of the present invention was prepared. The properties of the silicone rubber obtained by curing this room temperature curable organopolysiloxane composition were measured after the initial stage and after the heat resistance test, and the results are shown in Table 1.

Example 3 100 parts by weight of dimethylpolysiloxane having a viscosity of 3,000 centipoise and having both ends of the molecular chain blocked with trimethoxysiloxy groups, BET
10 parts by weight of dry silica fine powder having a specific surface area of 110 m ² / g and having its surface hydrophobized with hexamethyldisilazane, and a sieving residue of 325 mesh of 0.0
2% by weight of yellow iron oxide fine powder (manufactured by Nippon Beni Kogyo Co., Ltd .; trade name NYB-40) 2 parts by weight of red iron oxide fine powder having a sieve residue of 325 mesh of 0.22% by weight (Japan 5 parts by weight of Bengara Kogyo Co., Ltd. (trade name: Bengala) were mixed at room temperature for 30 minutes until uniform, and further heated to 150 ° C. under reduced pressure of 40 mmHg to mix. Then, after cooling this to room temperature, 2 parts by weight of methyltrimethoxysilane and diisopropoxy-bis (ethylacetoacetate) titanium were added thereto in an amount of 0.
After adding 5 parts by weight, the mixture was uniformly mixed to prepare a room temperature curable organopolysiloxane composition of the present invention. The properties of the silicone rubber obtained by curing this room temperature curable organopolysiloxane composition were measured after the initial stage and after the heat resistance test, and the results are shown in Table 1.

Example 4 100 parts by weight of dimethylpolysiloxane having a viscosity of 3,000 centipoise and having both ends of its molecular chain blocked with trimethoxysiloxy groups, BET
5 parts by weight of dry silica fine powder having a specific surface area of 110 m ² / g and hydrophobizing the surface with hexamethyldisilazane, and a sieving residue of 325 mesh of 0.02
% By weight, and yellow iron oxide fine powder in which aluminate was solid-solved (manufactured by Titanium Industry Co., Ltd .; trade name LL-KLO) 10
The parts by weight were mixed at room temperature for 30 minutes until uniform, and further heated to 150 ° C. under reduced pressure of 40 mmHg to mix. Then, after cooling this to room temperature, under moisture exclusion,
To this, 2 parts by weight of methyltrimethoxysilane and 0.5 parts by weight of diisopropoxy-bis (ethylacetoacetate) titanium were added and mixed uniformly to prepare a room temperature curable organopolysiloxane composition of the present invention. did. The properties of the silicone rubber obtained by curing this room temperature curable organopolysiloxane composition were measured after the initial stage and after the heat resistance test, and the results are shown in Table 1.

Example 5 100 parts by weight of dimethylpolysiloxane having a viscosity of 3,000 centipoise and having both ends of the molecular chain blocked with trimethoxysiloxy groups, BET
10 parts by weight of dry silica fine powder having a specific surface area of 110 m ² / g and having its surface hydrophobized with hexamethyldisilazane, and a sieving residue of 325 mesh of 0.0
2% by weight of yellow iron oxide fine powder in which aluminate was solid-solved (manufactured by Titanium Industry Co., Ltd .; trade name LL-XLO) 2
5 parts by weight of red iron oxide fine powder (manufactured by Nippon Benji Kogyo Co., Ltd .; trade name Tensho Mark Bengala) having a 325 mesh sieve residue of 0.22% by weight until uniform at room temperature for 30 minutes. After mixing, further under reduced pressure of 40 mmHg,
Heated to 150 ° C. and mixed. Then, after cooling this to room temperature, 2 parts by weight of methyltrimethoxysilane and 0.5 part by weight of diisopropoxy-bis (ethyl acetoacetate) titanium were added thereto under moisture exclusion, and then uniformly mixed. A room temperature curable organopolysiloxane composition of the present invention was prepared. The properties of the silicone rubber obtained by curing this room temperature curable organopolysiloxane composition were measured after the initial stage and after the heat resistance test, and the results are shown in Table 1.

COMPARATIVE EXAMPLE 1 100 parts by weight of dimethylpolysiloxane having a viscosity of 3,000 centipoise and having both ends of the molecular chain blocked with trimethoxysiloxy groups, BET
10 parts by weight of dry silica fine powder having a specific surface area of 110 m ² / g and having its surface hydrophobized with hexamethyldisilazane, and a sieving residue of 325 mesh of 0.2
After mixing 5 parts by weight of 2% by weight of red iron oxide fine powder (manufactured by Nippon Beni Kogyo Co., Ltd .; trade name Tengara Mark Bengala) at room temperature for 30 minutes until uniform, further under reduced pressure of 40 mmHg and 150 ° C. Heated to mix. Then, after cooling this to room temperature, 2 parts by weight of methyltrimethoxysilane and 0.5 part by weight of diisopropoxy-bis (ethyl acetoacetate) titanium were added thereto under moisture exclusion, and then uniformly mixed. A comparative room temperature curable organopolysiloxane composition was prepared. The properties of the silicone rubber obtained by curing this room temperature curable organopolysiloxane composition were measured after the initial stage and after the heat resistance test, and the results are shown in Table 1.

Comparative Example 2 100 parts by weight of dimethylpolysiloxane having a viscosity of 3,000 centipoise and having both ends of the molecular chain blocked with trimethoxysiloxy groups, BET
5 parts by weight of dry silica fine powder having a specific surface area of 110 m ² / g and having its surface hydrophobized with hexamethyldisilazane, and a sieve residue of 325 mesh of 0.22
After mixing 25 parts by weight of red iron oxide fine powder (manufactured by Nippon Benji Kogyo Co., Ltd .; trade name Tenshi-Bengara) in a weight percentage of 30 minutes at room temperature until uniform, further under reduced pressure of 40 mmHg up to 150 ° C. Heated and mixed. Then, after cooling this to room temperature, 2 parts by weight of methyltrimethoxysilane and 0.5 part by weight of diisopropoxy-bis (ethyl acetoacetate) titanium were added thereto under moisture exclusion, and then uniformly mixed. A comparative room temperature curable organopolysiloxane composition was prepared. The properties of the silicone rubber obtained by curing this room temperature curable organopolysiloxane composition were measured after the initial stage and after the heat resistance test, and the results are shown in Table 1.

Example 6 100 parts by weight of dimethylpolysiloxane having a viscosity of 2,250 centipoise and having both ends of its molecular chain blocked with dimethylhydroxysiloxy groups,
A yellow iron oxide fine powder having a BET specific surface area of 110 m ² / g and a dry silica fine powder 5 parts by weight obtained by hydrophobizing the surface with hexamethyldisilazane, and a sieving residue of 325 mesh of 0.02% by weight. After mixing 10 parts by weight of powder (manufactured by Nippon Benigaku Co., Ltd .; trade name NYB-40) at room temperature for 30 minutes until uniform, the mixture was further heated to 150 ° C. under reduced pressure of 40 mmHg and mixed. Then, after cooling this to room temperature, 9 parts by weight of methyltrioxime silane and 0.5 parts by weight of dibutyltin dilaurate were added thereto under moisture exclusion, and then uniformly mixed to obtain the room temperature curable organo of the present invention. A polysiloxane composition was prepared.
The properties of the silicone rubber obtained by curing this room temperature curable organopolysiloxane composition were measured after the initial stage and after the heat resistance test, and the results are shown in Table 1.

[Comparative Example 3] 100 parts by weight of dimethylpolysiloxane having a viscosity of 2,250 centipoise and having both ends of its molecular chain blocked with dimethylhydroxysiloxy groups,
Red iron oxide fine particles having a BET specific surface area of 110 m ² / g and 5 parts by weight of dry silica fine powder obtained by hydrophobizing the surface with hexamethyldisilazane and having a sieve residue of 0.02% by weight with 325 mesh. After mixing 10 parts by weight of powder (manufactured by Nippon Beni Kogyo Co., Ltd .; trade name Tengara Mark Bengala) at room temperature for 30 minutes until uniform, further 40 mmHg
Under reduced pressure, heated to 150 ° C. and mixed. Then, after cooling this to room temperature, 9 parts by weight of methyltrioxime silane and 0.5 part by weight of dibutyltin dilaurate were added thereto under moisture exclusion, and then uniformly mixed to give a comparative room temperature curable organopolyene. A siloxane composition was prepared.
The properties of the silicone rubber obtained by curing this room temperature curable organopolysiloxane composition were measured after the initial stage and after the heat resistance test, and the results are shown in Table 1.

[0039]

[Table 1]

[0040]

The room temperature-curable organopolysiloxane composition of the present invention is characterized by being cured by moisture to form a silicone rubber having excellent heat resistance in a high temperature range.

Front page continuation (72) Inventor Harumi Kodama 2-2 Chikusaigan, Ichihara, Chiba Toray Dow Corning Silicone Co., Ltd.

Claims (3)

[Claims] 1. (A) A diorganopolysiloxane having a viscosity of 20 to 1,000,000 centipoise at 25 ° C. and having at least two silicon atom-bonded hydroxyl groups or silicon atom-bonded alkoxy groups in one molecule. 100 parts by weight, (B) 0.1 to 25 parts by weight of an organosilicon compound having at least two hydrolyzable groups of silicon atom bonds in one molecule, (C) 0.01 to 10 parts by weight of a curing catalyst, and ( D) A room temperature curable organopolysiloxane composition comprising 0.1 to 50 parts by weight of yellow iron oxide fine powder. 2. (A) A diorganopolysiloxane having a viscosity of 20 to 1,000,000 centipoise at 25 ° C. and having at least two silicon atom-bonded hydroxyl groups or silicon atom-bonded alkoxy groups in one molecule. 100 parts by weight, (B) 0.1 to 25 parts by weight of an organosilicon compound having at least two hydrolyzable groups of silicon atom bonds in one molecule, (C) 0.01 to 10 parts by weight of a curing catalyst, ( A room temperature curable organopolysiloxane composition comprising D) yellow iron oxide fine powder 0.1 to 50 parts by weight and (E) red iron oxide fine powder 0.1 to 50 parts by weight. 3. The room temperature curable organopolysiloxane composition according to claim 1 or 2, wherein the component (D) is a yellow iron oxide fine powder in which aluminate or an aluminate is solid-dissolved.