JP2001181507A - Abrasive-forming silicone rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abrasive-forming silicone rubber composition capable of forming a nonexpanded silicone rubber which excels in abrasive properties and durability. SOLUTION: The abrasive-forming silicone rubber composition comprises (A) 100 pts.wt. curable diorganopolysiloxane, (B) 10-1,000 pts.wt. abrasive particles, and (C) a sufficient amount of a curing agent to cure the composition and can form a nonexpanded silicone rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a silicone rubber composition for forming an abrasive, and more particularly, to a silicone rubber composition for forming an abrasive capable of forming a non-foamed silicone rubber having excellent abrasive properties and durability.

[0002]

2. Description of the Related Art Silicone rubber compositions containing abrasive particles include silicone rubber compositions consisting of silicone rubber, 90 to 150 grit, and primer.
(See JP-A-48-101694), and an expandable silicone rubber composition containing abrasive particles (see JP-A-6-101694).
No. 0-104654).

However, Japanese Patent Laid-Open No. 48-101694
Japanese Patent Laid-Open No. 60-104654 does not disclose a specific composition of a silicone rubber composition, and Japanese Patent Application Laid-Open No. 60-104654 discloses a foamable silicone rubber composition. The silicone rubber obtained by curing has a problem of poor abrasiveness and durability.

[0004]

The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, an object of the present invention is to provide a silicone rubber composition for forming an abrasive, which can form a non-foamed silicone rubber having excellent abrasiveness and durability.

[0005]

According to the present invention, there are provided (A) 100 parts by weight of a curable diorganopolysiloxane, (B) 10 to 1,000 parts by weight of abrasive particles, and (C) a curing agent. The present invention relates to a silicone rubber composition for forming an abrasive, which is formed in an amount sufficient for curing and forms a non-foamed silicone rubber.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The silicone rubber composition for forming an abrasive according to the present invention will be described in detail. The curable diorganopolysiloxane of the component (A) is the main component of the present composition and has a substantially linear molecular structure, but a part of the molecular chain may be branched. Examples of the group bonded to the silicon atom in the component (A) include an alkyl group such as a methyl group, an ethyl group and a propyl group; an alkenyl group such as a vinyl group, an allyl group and a hexenyl group; a phenyl group and a tolyl group. An aryl group; an aralkyl group such as a benzyl group or a phenethyl group;
Examples include substituted or unsubstituted monovalent hydrocarbon groups such as halogenated alkyl groups such as 3,3-trifluoropropyl group and 3-chloropropyl group, and other small amounts of hydroxyl groups. As such a component (A), a low-viscosity liquid diorganopolysiloxane to a high-viscosity raw rubber-like diorganopolysiloxane can be used. The degree of polymerization of component (A) is not limited, but the average degree of polymerization is from 3,000 to 10,000.
00 is preferred. When the present composition is of a hydrosilylation-curable type, the component (A) is preferably a diorganopolysiloxane having at least two alkenyl groups in one molecule.

The abrasive particles of the component (B) are components for imparting abrasiveness to the silicone rubber obtained by curing the present composition, and examples thereof include irregular shapes, spherical shapes, and flat shapes. The silicone rubber obtained may have various particle sizes depending on the degree of abrasiveness of the obtained silicone rubber.
The average particle diameter is preferably from 0.01 to 1000 μm, more preferably from 0.01 to 200 μm, and particularly preferably from 0.01 to 100 μm. As the abrasive particles of the component (B), fused silica particles, quartz particles, silicon oxide particles such as synthetic quartz particles, aluminum oxide particles, cerium oxide particles, silicon nitride particles, aluminum nitride particles, boron nitride particles, Silicon carbide particles are exemplified.

In the present composition, the content of the component (B) is
(A) 10 to 1,000 parts by weight, preferably 10 to 500 parts by weight, more preferably 50 to 300 parts by weight, particularly preferably 100 to 300 parts by weight per 100 parts by weight of component (A). Parts by weight. This is because if the content of the component (B) is less than the lower limit of the above range, the abrasiveness of the obtained silicone rubber tends to decrease,
On the other hand, when the content exceeds the upper limit of the above range, the moldability of the obtained composition tends to decrease.

The curing agent of component (C) is a component for curing the present composition. When the present composition is a radical reaction-curing type, it is an organic peroxide. In the case of a hydrosilylation reaction-curing type, an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule and a platinum-based catalyst are used.

The organic peroxides of component (C) include dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxide and t-butyl peroxide.
-Butylcumyl peroxide, 2,5-dimethyl-
2,5-di (t-butylperoxy) hexane, 1,1-
Bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, benzoyl peroxide, p-methylbenzoyl peroxide, o-methylbenzoyl peroxide, and t-butylperoxyisopropyl monocarbonate are exemplified.

In the present composition, the content of the organic peroxide is sufficient to cure the present composition, and is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the component (A). And particularly preferably 0.1 to 5 parts by weight. This is because if the content of the organic peroxide is less than the lower limit of the above range, the obtained composition tends to be hardened sufficiently, while if the content of the organic peroxide exceeds the upper limit of the above range, the resulting silicone This is because rubber tends to foam.

On the other hand, the organohydrogenpolysiloxane of the component (C) is a straight-chain, partially branched straight-chain,
It has a molecular structure such as a branched chain or a ring, and as a group other than a hydrogen atom bonded to a silicon atom, an alkyl group such as a methyl group, an ethyl group, or a propyl group; a phenyl group, a tolyl group, etc. Aryl group; a substituted or unsubstituted monovalent hydrocarbon group having no aliphatic unsaturated group such as a halogenated alkyl group such as a 3,3,3-trifluoropropyl group and a 3-chloropropyl group. The viscosity of the organohydrogenpolysiloxane is not limited, but is preferably 1 to 10,000 mPa · s at 25 ° C.

In the present composition, the content of the organohydrogenpolysiloxane is an amount sufficient to cure the present composition. Preferably, the content of silicon is based on 1 mol of the alkenyl group in the component (A). The atomic bond hydrogen atom is 0.
The amount is 5 to 10 mol. This is because if the content of the organohydrogenpolysiloxane is less than the lower limit of the above range, the obtained composition tends to be insufficiently cured, while if it exceeds the upper limit of the above range,
This is because the obtained silicone rubber tends to foam.

The platinum catalyst of the component (C) includes chloroplatinic acid, an alcohol solution of chloroplatinic acid, an olefin complex of platinum, an alkenylsiloxane complex of platinum, a carbonyl complex of platinum, and a platinum-based catalyst of these. contains,
Examples include particles made of a thermoplastic resin such as an acrylic resin, a polycarbonate resin, and a silicone resin.

In the present composition, the content of the platinum-based catalyst is an amount sufficient to cure the present composition, and preferably, the platinum metal is contained in the present composition in an amount of 0.1 to 100 by weight.
0 ppm, particularly preferably 0.1 to 500 ppm.
It is the amount that becomes ppm.

Further, the present composition contains (D) a reinforcing silica having a BET specific surface area of at least 50 m ² / g in order to improve the mechanical strength of the silicone rubber obtained by curing the composition. Is preferred. As the reinforcing silica of the component (D), a dry method silica powder, a wet method silica powder, and a surface thereof are treated with an organosilicon compound such as an organoalkoxysilane, an organochlorosilane, an organosilazane, or an organosiloxane oligomer. Examples thereof include silica powder. In the present composition, the content of the component (D) is not limited, but is preferably 1 to 50 parts by weight based on 100 parts by weight of the component (A). In addition, when the component (D) is blended with the component (A), a diorganosiloxane oligomer having a silanol group at both ends of the molecular chain may be added to improve the dispersibility.
Examples of the oligomer include a dimethylsiloxane oligomer having silanol groups at both ends of a molecular chain, a methylvinylsiloxane oligomer having silanol groups at both ends of a molecular chain, a dimethylsiloxane / methylvinylsiloxane copolymer oligomer having silanol groups at both ends of a molecular chain, and both ends of a molecular chain. Examples thereof include silanol group-blocked methylphenylsiloxane oligomers. The addition amount of this oligomer is 100 parts (D).
The amount is preferably 1 to 50 parts by weight with respect to parts by weight.

The composition of the present invention may further contain, as other optional components, inorganic fillers such as diatomaceous earth, mica, talc, magnesium oxide, aluminum hydroxide, and magnesium hydroxide; carbon black, red iron oxide, titanium dioxide and the like. Pigment; heat-resistance imparting agent such as rare earth oxide, rare earth hydroxide, cerium silanolate, cerium fatty acid salt; flame retardant imparting agent such as fumed titanium dioxide, manganese carbonate, zinc carbonate; internal addition such as calcium stearate Mold release agent; may contain a plasticizer and the like.

The method for preparing the present composition is not limited. For example, the above components (A) to (C) and, if necessary, component (D) and / or other components may be mixed with a kneader mixer, a Henschel mixer. , A loss mixer, a method of mixing with a kneading device such as a two-roller. In particular, since the properties of the present composition and the properties of the silicone rubber obtained by curing the composition are excellent, a silicone rubber base compound prepared by heating and kneading the components (A) and (D) is used.
It is preferable to knead the components (B) and (C).

The silicone rubber obtained by curing the present composition has a small amount of deformation at the time of polishing and improves both abrasion and durability. Therefore, the type A durometer hardness specified in JIS K 6253 is 50. The hardness is preferably 70 or more, more preferably 70 or more, more preferably 80 or more, and particularly preferably 90 or more. preferable. Further, since the silicone rubber is not easily broken when a load is applied, the tensile strength specified in JIS K6251 is preferably 3 MPa or more, and in particular, the tensile strength is preferably 5 MPa or more. preferable.

The present composition can be cured to form a silicone rubber having excellent abrasiveness and durability. This silicone rubber can be formed into a disk shape, a sheet shape, or a tape shape. The abrasive made of silicone rubber can be used as an abrasive for optical parts such as lenses, an abrasive for metal parts such as precision mechanical parts, and an abrasive for electronic parts such as semiconductor wafers.

[0021]

EXAMPLES The silicone rubber composition for forming an abrasive according to the present invention will be described in more detail with reference to Examples. In addition, the viscosity in an Example is a value in 25 degreeC.

EXAMPLE 1 A dimethylsiloxane-methylvinylsiloxane copolymer having a molecular weight of 5,000 and a dimethylvinylsiloxy group at both ends of the molecular chain having a degree of polymerization of 5,000 (molar ratio of dimethylsiloxane unit to methylvinylsiloxane unit = 99.
85: 0.15) 100 parts by weight, BET specific surface area 200
35 parts by weight of dry-processed silica powder of m ² / g and 10.0 parts by weight of a dimethylsiloxane oligomer having a viscosity of 60 mPa · s and capped with silanol groups at both ends of a molecular chain are charged into a kneader mixer and kneaded under heating to obtain a silicone rubber. A base compound was prepared. Next, 100 parts by weight of the base compound and an average particle size of 5 prepared by a pulverization method were used.
200 parts by weight of irregularly shaped quartz particles of 200 μm are kneaded on a two-roll mill, and further, 2,5-dimethyl-2,5-di (t
-Butyl peroxy) hexane was kneaded with 0.4 part by weight to prepare a silicone rubber composition for forming an abrasive.

The silicone rubber composition is heated at 170 ° C. for 1 hour.
After press vulcanization for 0 minutes, secondary vulcanization was performed at 200 ° C. for 4 hours to prepare a non-foamed silicone rubber sheet. The hardness of this silicone rubber was 93 as measured by a type A durometer specified in JIS K6253.
Also, from this silicone rubber sheet, JIS K62
A dumbbell-shaped No. 3 test piece specified in No. 51 was prepared, and its tensile strength and elongation at break were measured according to JIS K6251.
The tensile strength was measured according to the method specified in 8.
It was 6 MPa, and the elongation at break was 60%.

Next, an abrasive test was performed using the silicone rubber sheet. The test method was 40 ° C, 90% R
A 15 mm × 25 mm × 2 mm silicone rubber was pressed against the surface of a cold-rolled steel sheet having a uniform rust on the surface thereof under running water with a force of 78 N in a H atmosphere.
The polishing was performed 00 times. After polishing, the state of rust on the steel sheet and the presence or absence of scratches on the steel sheet metal part were visually observed. As a result, the rust on the steel plate can be removed uniformly,
There were no abrasive scratches on the steel plate. The silicone rubber sheet was not damaged.

[Example 2] Dimethylvinylsiloxy group-blocked dimethylsiloxane at both ends of a molecular chain having a polymerization degree of 5,000.
Methyl vinyl siloxane copolymer (molar ratio of dimethyl siloxane unit to methyl vinyl siloxane unit = 99.8
5: 0.15) 100 parts by weight, BET specific surface area 200 m
² / g dry process silica powder 35 parts by weight and viscosity 6
10.0 parts by weight of a dimethylsiloxane oligomer having a silanol group at both ends of a molecular chain of 0 mPa · s was charged into a kneader mixer and kneaded under heating to prepare a silicone rubber-based compound. Next, 100 parts by weight of this base compound and an average particle size of 5 μm prepared by a pulverization method were used.
200 parts by weight of irregularly shaped quartz particles having a m of 2 m were kneaded on a two-roll mill. With respect to 1 mol of vinyl groups contained in the dimethylsiloxane / methylvinylsiloxane copolymer in the base compound, 3.3 mol of silicon-bonded hydrogen atoms contained in the dimethylsiloxane / methylhydrogensiloxane copolymer were used. ), 0.03 parts by weight of 1-ethynyl-cyclohexanol, and two rolls of 1,3-divinyltetramethyldisiloxane complex of platinum (in the present composition, the amount of platinum metal becomes 2 ppm by weight). The above mixture was kneaded to prepare a silicone rubber composition for forming an abrasive.

This silicone rubber composition was cured in the same manner as in Example 1 to prepare a non-foamed silicone rubber sheet. The hardness of this silicone rubber is determined according to JIS K6
It was 90 when measured with a type A durometer specified in 253. A dumbbell-shaped No. 3 test piece specified in JIS K6251 was prepared from this silicone rubber sheet, and its tensile strength and elongation at break were determined according to J.
The tensile strength was 9.4 MPa and the elongation at break was 75% when measured according to the method specified in IS K6251.

Next, an abrasion test was conducted in the same manner as in Example 1 using this silicone rubber sheet. After polishing, the state of rust on the steel sheet and the presence or absence of scratches on the steel sheet metal part were visually observed. As a result, the rust on the steel sheet could be uniformly removed, and the steel sheet had no polishing scratches. The silicone rubber sheet was not damaged.

COMPARATIVE EXAMPLE 1 A dimethylsiloxane-methylvinylsiloxane copolymer having a molecular weight of 5,000 and a dimethylvinylsiloxy group at both ends of the molecular chain having a polymerization degree of 5,000 (molar ratio of dimethylsiloxane units to methylvinylsiloxane units = 99.
85: 0.15) 100 parts by weight, BET specific surface area 200
35 parts by weight of dry-processed silica powder of m ² / g and 10.0 parts by weight of a dimethylsiloxane oligomer having a viscosity of 60 mPa · s and capped with silanol groups at both ends of a molecular chain are charged into a kneader mixer and kneaded under heating to obtain a silicone rubber. A base compound was prepared. Next, 100 parts by weight of this base compound and 2,5-dimethyl-2,5-di (t
0.4 parts by weight of -butylperoxy) hexane was kneaded on a two-roll mill to prepare a silicone rubber composition for forming an abrasive.

This silicone rubber composition was cured in the same manner as in Example 1 to prepare a non-foamed silicone rubber sheet. The hardness of this silicone rubber is determined according to JIS K6
It was 48 when measured with a type A durometer specified in 253. A dumbbell-shaped No. 3 test piece specified in JIS K6251 was prepared from this silicone rubber sheet, and its tensile strength and elongation at break were determined according to J.
The tensile strength was 9.2 MPa and the elongation at break was 350% when measured according to the method specified in IS K6251.
Met.

Next, an abrasion test was performed in the same manner as in Example 1 using this silicone rubber sheet. After polishing, the state of rust adhesion of the steel sheet, and the presence or absence of scratches on the steel sheet metal part were visually observed, but there was no polishing scratch on the steel sheet,
Rust of the steel plate could be removed only about half of Example 1. The silicone rubber sheet was not damaged.

Comparative Example 2 A dimethylsiloxane-methylvinylsiloxane copolymer having a molecular weight of 5,000 and a dimethylvinylsiloxy group at both ends of the molecular chain having a degree of polymerization of 5,000 (molar ratio of dimethylsiloxane units to methylvinylsiloxane units = 99.
85: 0.15) 100 parts by weight, BET specific surface area 200
35 parts by weight of dry-processed silica powder of m ² / g and 10.0 parts by weight of a dimethylsiloxane oligomer having a viscosity of 60 mPa · s and capped with silanol groups at both ends of a molecular chain are charged into a kneader mixer and kneaded under heating to obtain a silicone rubber. A base compound was prepared. Next, 100 parts by weight of this base compound and an average particle size of 5 prepared by a pulverization method were used.
μm irregular shaped quartz particles 200 parts by weight, azobisisobutyronitrile 2 parts by weight, bis (4-methylbenzoyl) peroxide 0.5 part by weight, and 2,5-dimethyl-2,5-di (t- Butylperoxy) hexane 1
A part by weight was kneaded on a two-roll mill to prepare a silicone rubber composition for forming an abrasive.

The silicone rubber composition is separated into sheets, vulcanized in an oven at 250 ° C. for 5 minutes, and secondarily vulcanized at 200 ° C. for 4 hours to obtain a foam having an expansion ratio of about 2 times. A silicone rubber sheet was made. The hardness of this silicone rubber is defined as Type A specified in JIS K6253.
It was 40 when measured with a durometer. In addition, JIS K 625 is obtained from this silicone rubber sheet.
A dumbbell-shaped No. 3 test piece specified in 1 was prepared, and its tensile strength and elongation at break were measured in accordance with the method specified in JIS K6251. The tensile strength was 3.8 M
Pa, and the elongation at break was 150%.

Next, an abrasion test was performed using this silicone rubber sheet in the same manner as in Example 1. As a result of the polishing, the foamed silicone rubber sheet was damaged and almost no rust was removed from the steel sheet. could not.

[0034]

The silicone rubber composition for forming an abrasive according to the present invention is characterized in that it can form a non-foamed silicone rubber having excellent abrasiveness and durability.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/14 C08K 5/14 C08L 83/05 C08L 83/05 83/07 83/07 F-term (reference) 3C063 AA01 BB01 BB03 BC04 FF23 4J002 CP031 CP032 CP081 DD028 DE096 DE146 DE168 DF016 DJ006 DJ016 EK037 EK047 EK087 EZ008 FD010 FD060 FD090 FD130 FD160 GT00

Claims (5)

[Claims] (A) 100 parts by weight of a curable diorganopolysiloxane, (B) 10 to 1,000 parts by weight of abrasive particles, and (C) a curing agent in an amount sufficient to cure the present composition. A silicone rubber composition for forming an abrasive, characterized by forming a non-foamed silicone rubber. 2. The method according to claim 1, wherein (D) a reinforcing silica powder having a BET specific surface area of at least 50 m ² / g is added to the component (A).
The silicone rubber composition for forming an abrasive according to claim 1, wherein the silicone rubber composition is contained in an amount of 1 to 50 parts by weight based on 0 part by weight. 3. The at least one type of polishing wherein the component (B) is selected from the group consisting of silicon oxide particles, aluminum oxide particles, cerium oxide particles, silicon nitride particles, aluminum nitride particles, boron nitride particles, and silicon carbide particles. 2. The silicone rubber composition for forming an abrasive according to claim 1, wherein the composition is an abrasive particle. 4. The silicone rubber composition for forming an abrasive according to claim 1, wherein the component (C) is an organic peroxide. 5. The component (A) is a diorganopolysiloxane having at least two alkenyl groups in one molecule, and the component (C) is an organopolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule. 2. A hydrogen catalyst comprising a hydrogen polysiloxane and a platinum catalyst.
The silicone rubber composition for forming an abrasive according to the above.