Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-04-11
2001-12-11
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S265000, C524S266000, C525S100000, C525S393000, C525S446000, C528S029000
Reexamination Certificate
active
06329460
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a polysiloxane composition and a rubber composition containing a surface-treated inorganic solid particle treated, on the surface thereof, with the same well as a resin composition containing a resin, an inorganic filler and a polysiloxane suitable for use as a paint, adhesive, sealant, etc. due to a superior stability of dispersion of a filler.
2. Description of the Related Art
In the past, inorganic solid particles such as carbon black, calcium carbonate, alumina, aluminum sulfate, barium sulfate, calcium sulfate, silica, talc, clay, diatomaceous earth, and mica have been used in numerous fields such as rubber, cosmetics, synthetic resins, paints, adhesives, and magnetic tape. Among these, inorganic solid particles are extensively used as fillers for various types of rubber. These inorganic solid particles sometimes have polar groups on their surface. The inclusion of inorganic solid particles is problematic in that it causes a drop in the knit of the mix with the rubber. Rubber compositions containing metal oxides containing silica, in particular silica, among these inorganic solid particles are used for tire tread rubber compositions low in heat buildup and superior in abrasion resistance. Rubber compositions containing silica are problematic in that the viscosity at the time before vulcanization rises, the vulcanization is delayed, and the knit of the mix falls and the productivity consequently deteriorates. Further, in a rubber composition containing silica, poor dispersion of the silica occurs and the properties of the silica are not sufficiently utilized.
To solve the above problem, the present inventors previously found that the unvulcanized physical properties and vulcanized physical properties of the rubber composition containing silica can be improved by blending an alkoxysilyl group-containing polysiloxane in a rubber composition containing silica, whereby a reaction between the silanol groups on the surface of the silica and alkoxysilyl groups is caused to thereby cover the surface of the silica (see Japanese Unexamined Patent Publication (Kokai) No. 9-111044). However, it was found that, when the polysiloxane is stored for a long period, an increase in the viscosity is seen and the improvement in the unvulcanized physical properties and vulcanized physical properties in a rubber composition containing silica using such a polysiloxane is small.
In addition, resin compositions for paints, adhesives, sealants, etc. use pigments and other fillers for coloring, blocking, reinforcement, extension, imparting weather resistance, or imparting conductivity, a magnetic property, or other properties. Fillers are classified into inorganic fillers and organic fillers, but the former is generally low in affinity with various resins, and therefore, poor dispersion, aggregation, settling, etc. easily occur and, in turn, painting or installation become impossible, uneven coloring, blocking, etc. occur, and other problems arise.
Among the inorganic fillers, silica is used in paints as an extender pigment or delustering agent and is used in adhesives for improvement of the hardness etc., but due to the aggregating force arising from the silanol groups on the surface, poor dispersion and settling in particular easily occur or, once precipitating, redispersion is extremely difficult.
To solve this problem, various dispersants and anti-settling agents for use for paints, adhesives, sealants, and other resin compositions have been studied in the past.
For example, Japanese Unexamined Patent Publication (Kokai) No. 5-163463 describes that a “condensate of an organoalkoxysiloxane having the general formula:
RSi(OR′)
3
where R represents a C
1
to C
8
organic group and R′ represents a C
1
to C
5
alkyl group or C
1
to C
4
acyl group, i.e. an organosiloxane having a weight average molecular weight converted to polystyrene of 3,000 to 100,000” improves the dispersion of the pigment and acts as a condensing agent in a coating composition.
However, in the above system, dual use of colloidal silica is essential. Further, the publication does not describe anything about the effect of an organopolysiloxane as a dispersant and anti-settling agent in a coating composition where the pigment is silica and does not solve the problem of poor dispersion, aggregation, settling, and difficult redispersion of silica.
SUMMARY OF THE INVENTION
Accordingly, the objects of the present invention are to solve the above-mentioned problems and to provide a polysiloxane superior in storage stability, surface-treated inorganic solid particles giving good unvulcanized physical properties and vulcanized physical properties and improved abrasion resistance when blended in a rubber, and a rubber composition containing the same and superior in processability when unvulcanized, low heat buildup of the vulcanized product, abrasion resistance, and other properties.
Accordingly, another object of the present invention is to provide a resin composition containing an inorganic filler which is superior in the stability of dispersion of the inorganic filler, etc.
The present inventors found that, when adding a specific polysiloxane to a resin composition for a paint, adhesive, sealant, etc., it is possible to make poor dispersion, aggregation, settling, etc. of the filler harder to occur and enable easy redispersion of the filler by stirring etc. when it settles, whereby the present invention has been completed.
In accordance with the present invention, there is provided a polysiloxane composition comprising (i) an alkoxysilyl group-containing polysiloxane containing at least six siloxane structures having the following formula (I) in a molecule:
wherein R
1
represents a methyl group, ethyl group or phenyl group, and R
2
represents a group selected from the group consisting of hydrocarbon group and ether bond-containing hydrocarbon groups having 1 to 6 carbon atoms; and
(ii) an alcohol having the formula
R
4
(OR
5
)
n
—OH
wherein R
4
represents a C
1
-C
18
alkyl group (e.g., a methyl, ethyl, propyl, butyl, hexyl, pentyl, heptyl, octyl, octadecyl group), a phenyl group or a benzyl group, R
5
is C
1
-C
6
alkylene group (e.g., a methylene group, ethylene group, propylene group, butylene group, penten group, hexene group) and n is an integer of 0-20.
The alkoxysilyl group-containing polysiloxane is preferably a compound having the formula (II):
wherein R
1
and R
2
are as defined above, R
3
represents a group selected from the group consisting of hydrogen atom and organic groups having a molecular weight of not more than 3000, n is an integer of 6 to 1000, and m is an integer of 0 to 100.
Preferably, the present composition contains 1 to 100 parts by weight of the alcohol, based upon 100 parts by weight of the alkoxysilyl group-containing polysiloxane.
Further, the present invention provides a surface-treated inorganic solid particle obtained by surface treating 100 parts by weight of the inorganic solid particle with 1 to 50 parts by weight of the above-mentioned polysiloxane composition.
Further, the present invention provides a rubber composition containing 5 to 100 parts by weight of inorganic solid particles, based upon 100 parts by weight of rubber and 0.1 to 30% by weight, in terms of polysiloxane, of the polysiloxane composition based upon the content of the inorganic solid particle.
Further, the present invention provides a rubber composition containing 5 to 100 parts by weight of the surface-treated inorganic solid particle, based upon 100 parts by weight of the rubber.
Preferably the inorganic solid particle is a metal oxide containing silicon.
In accordance with the present invention, there is further provided a resin composition comprising (A) 100 parts by weight of a resin for a paint or adhesive, (B) 0.5 to 100 parts by weight of an inorganic filler, and (C) 0.1 to 30 parts by weight, based upon 100 parts by weight of the component (B), of a polysiloxane having the following formula (III):
wherein, R
6
Adachi Naoya
Ishikawa Kazunori
Kaido Hiroyuki
Yatsuyanagi Fumito
Arent Fox Kintner & Plotkin & Kahn, PLLC
Dawson Robert
The Yokohama Rubber Co. Ltd.
Zimmer Marc S.
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