Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2001-10-31
2003-12-09
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S104000, C525S106000, C525S539000, C524S492000
Reexamination Certificate
active
06660807
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an additive for organic resin and an organic resin composition. More specifically, the present invention relates to an additive for organic resin capable of imparting superior water repellency and surface lubricity to organic resin, and to an organic resin composition possessing superior water repellency and surface lubricity.
BACKGROUND OF THE INVENTION
It is known in the art to add liquid organopolysiloxanes to organic resins in order to impart water repellency and surface lubricity thereto and it is known to add powdery materials made up of the aforementioned organopolysiloxanes and inorganic powders (see Japanese Unexamined Patent Application Publication No. Hei 03(1991)-054236, Japanese Unexamined Patent Application Publication No. Hei 03(1991)-134050, and Japanese Unexamined Patent Application Publication No. 10(1998)-330617) in order to improve their compoundability. Although dimethylpolysiloxanes are typically used as the liquid organopolysiloxanes, they either cannot impart sufficient water repellency and surface lubricity to organic resins, or cause poor external appearance when resins are molded. In particular, liquid organopolysiloxanes with silicon-bonded hydrogen atoms have been disclosed in Japanese Unexamined Patent Application Publication No. 03(1991)-134050 and Japanese Unexamined Patent Application Publication No. 10(1998)-330617, but the above publications do not imply that the use of such liquid organopolysiloxanes can eliminate the above-mentioned problems.
It is an object of the present invention to provide an additive for organic resin capable of imparting superior water repellency and surface lubricity to organic resin and an organic resin composition possessing superior water repellency and surface lubricity.
SUMMARY OF THE INVENTION
The present invention is an additive for organic resin comprising a powder comprising (A) a liquid organopolysiloxane having at least 0.001 wt % of silicon-bonded hydrogen atoms and at least 50 dimethylsiloxy repeating units and (B) an inorganic powder; and an organic resin comprising the additive.
DESCRIPTION OF THE INVENTION
The present invention is an additive for organic resin comprising a powder comprising (A) a liquid organopolysiloxane having at least 0.001 wt % of silicon-bonded hydrogen atoms and at least 50 dimethylsiloxy repeating units and (B) an inorganic powder; and an organic resin comprising the additive.
First of all, detailed explanations are provided regarding the additive for organic resin. Component (A) is a liquid organopolysiloxane used to impart water repellency and surface lubricity to organic resin and it contains at least 0.001 wt %, preferably at least 0.005 wt %, of silicon-bonded hydrogen atoms. This is due to the fact that when the content of silicon-bonded hydrogen atoms is below the above-mentioned lower limits, the moldability of the organic resin composition may decrease. In addition, although there are no particular limitations concerning the upper limit of the content of silicon-bonded hydrogen atoms in component (A), preferably, it is not more than 1.5 wt %, more preferably, not more than 1 wt %, and, especially preferably, not more than 0.5 wt %. This is due to the fact that when the content of silicon-bonded hydrogen atoms exceeds the above-mentioned upper limits, it may not be possible to impart sufficient water repellency and surface lubricity to the organic resin composition. Component (A) is also characterized in that the number of dimethylsiloxy repeating units contained therein is at least 50, preferably at least 100, and especially preferably at least 200. This is due to the fact that when the number of dimethylsiloxy ((CH
3
)
2
SiO) repeating units is below the above-mentioned lower limits, it may not be possible to impart sufficient water repellency and surface lubricity to the organic resin composition. Organosiloxy repeating units other than the dimethylsiloxy repeating units in component (A) are exemplified by methylphenylsiloxy ((CH
3
)C
6
H
5
SiO), diphenylsiloxy ((C
6
H
5
)
2
SiO), methylhydrogensiloxy ((CH
3
)HSiO), methylsiloxy (CH
3
SiO), and phenylsiloxy (C
6
H
5
SiO). In addition, although there are no limitations concerning the viscosity of component (A) at 25° C., preferably, the viscosity is 40 to 100,000,000 mPa·s, more preferably 50 to 1,000,000 mPa·s, and especially preferably 100 to 1,000,000 mPa·s. This is due to the fact that if the viscosity at 25° C. is below the lower limit of the above-mentioned ranges, it may not be possible to impart sufficient water repellency and surface lubricity to the organic resin composition, and if it exceeds the upper limit of the above-mentioned ranges the compoundability of component (B) tends to decrease.
There are no particular limitations concerning the molecular structure of component (A), which can be, for example, linear, branched, linear with partial branching, cyclic, or resin-like. Component (A) is exemplified by liquid organopolysiloxanes described by general formula
In the above formula, R
1
represents a monovalent hydrocarbon group or a hydrogen atom and R
2
represents a hydrogen atom or a monovalent hydrocarbon group exclusive of methyl, with at least one of R
1
and R
2
in the molecule representing a hydrogen atom. The monovalent hydrocarbon groups of R
1
are exemplified by methyl, ethyl, propyl, and other alkyl groups; phenyl, tolyl, and other aryl groups; and vinyl, allyl, and other alkenyl groups. The monovalent hydrocarbon groups represented by R
2
are exemplified by ethyl, propyl, and other alkyl groups; phenyl, tolyl, and other aryl groups; and vinyl, allyl, and other alkenyl groups. R
3
is a monovalent hydrocarbon group exemplified by the same groups as R
1
. The subscript m in the above formula is an integer of at least 50. The subscript n in the above formula is an integer of 0 or greater, and when all R
1
in the formula are monovalent hydrocarbon groups, n is an integer of at least 1.
Component (A) is exemplified by the following liquid organopolysiloxanes. The subscript m in the formulas is the same as above, subscript p is at least 1, and subscript q is at least 1.
The inorganic powder of component (B) is exemplified by silica, alumina, magnesia, iron oxide, titania, zinc oxide, and other metal oxides; magnesium hydroxide, aluminum hydroxide, hydrotalcite, calcium aluminate hydrate, barium hydroxide, hard clay and other metal hydroxides; and, in addition to the above, calcium carbonate, calcium silicate, barium sulfate, talc, mica, clay, boron nitride, magnetite sand, glass beads, glass flakes, glass microballoons, diatomaceous earth, or powders consisting of metal, with metal oxide powders being especially preferable. Among such metal oxide powders, silica powder is particularly preferable. Such silica powder is exemplified by dry process silica (fumed silica) powder, wet process silica (precipitated silica) powder, fused silica powder, and crystalline silica powder. Although there are no limitations concerning the average particle size of component (B), preferably, it is not more than 100 &mgr;m, and, especially preferably, not more than 10 &mgr;m. In particular, in case of silica powder, its BET specific surface area is preferably at least 20 m
2
/g, more preferably at least 50 m
2
/g, and especially preferably at least 100 m
2
/g.
Although there are no limitations concerning the content of the above-described component (B) in the additive for organic resin of the present invention, preferably its content is 50 to 250 parts by weight, more preferably 50 to 200 parts by weight, and especially preferably 75 to 150 parts by weight per 100 parts by weight of the above-described component (A). This is due to the fact that when the content of component (B) is below the lower limit of the above-mentioned ranges, it may not be possible to impart sufficient water repellency and surface lubricity to the organic resin composition, and when it exceeds the upper limit of the above-mentioned ranges it is difficult to grind it into powder for
Furukawa Haruhiko
Morita Yoshitsugu
Shiromoto Koji
Ueki Hiroshi
Dow Corning Toray Silcone Co., Ltd.
Lee Rip A.
Wu David W.
Zombeck Alan
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