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
1999-08-24
2001-01-16
Moore, Margaret G. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C528S016000, C528S043000, C556S466000, C556S467000, C556S462000
Reexamination Certificate
active
06174968
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to oil gel compositions for use in cosmetics and pharmaceutical products, cable packing, etc. More particularly, this invention relates to such compositions containing polysiloxane block copolymers and which utilize hydrogenated aromatic group-containing silicone oils.
BACKGROUND OF THE INVENTION
Silicone gel compositions have been used in a variety of products, including sunscreen gels, moisturizing creams, antiperspirant creams, liquid foundations, and hair gels. Known silicone gel compositions include compositions comprised of silicone oil and wax, silicone oil and silica, and silicone oil and polyoxyalkylene-containing organopolysiloxanes, such as described in European Published Patent Application No. 0,568,102. That application identifies a number of possibilities for components useful as the silicone oil including low and high viscosity diorganopolysiloxanes, including polydimethylsiloxane, cyclic siloxanes, cyclic siloxane solutions of polydimethylsiloxane gums, etc.
Linear block copolymers of polystyrene and polydimethylsiloxane have been synthesized, both by graft and block copolymerization. In block copolymerization of such linear polymers, polystyrene is produced by anionic polymerization with an organo lithium initiator and the living polymer (PS—Li+) created thereby is reacted with hexamethylcyclotrisiloxane, (Me
2
SiO)
3
, in the presence of a polar promoter wherein a block of polydimethylsiloxane grows on the end of the living vinyl aromatic hydrocarbon polymer block. U.S. Pat. No. 5,618,903 describes a block copolymer which is an anionically polymerized block copolymer which is comprised of at least one block of high density (HDPE) polyethylene and at least one block of a polysiloxane, e.g., polydimethylsiloxane. These polymers are useful for impact modification of engineering thermoplastics, flow promoters, and forming coatings with low energy surfaces but have not been used or suggested for use as components of oil gels.
SUMMARY OF THE INVENTION
This invention is a silicone oil gel composition which is comprised of a polysiloxane, preferably polydimethylsiloxane, block copolymer having at least two of the following types of blocks: polystyrene, polyethylene, and hydrogenated polyisoprene wherein the overall number average molecular weight is from 1000 to 50,000, the polystyrene content (PSC) is 15% or less by weight, the polystyrene block number average molecular weight is from 0 to 10,000, the hydrogenated polyisoprene block number average molecular weight is from 0 to 10,000, and the polyethylene number average block molecular weight is from 0 to 10,000, the polydimethyl-siloxane number average molecular weight is from 1000 to 49,000, wherein the block copolymer is dissolved in a hydrogenated aromatic group-containing silicone oil which is preferably a copolymer of polydimethylsiloxane and polymethylphenylsiloxane with a polydimethylsiloxane content greater than 50% by weight.
REFERENCES:
patent: 5618903 (1997-04-01), Hoxmeier et al.
patent: 5670688 (1997-09-01), Dinh et al.
patent: 5693713 (1997-12-01), Hoxmeier et al.
patent: 0568102 A1 (1993-04-01), None
patent: 0751170 A2 (1996-06-01), None
patent: 61-113646 (1986-05-01), None
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patent: 01079106 (1989-03-01), None
patent: 01207354 (1989-08-01), None
patent: 01250307 (1989-10-01), None
patent: 02088513 (1990-03-01), None
patent: 05178734 (1993-07-01), None
Haas Donald F.
Moore Margaret G.
Shell Oil Company
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