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
1999-11-17
2001-12-18
Mullis, Jeffrey (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S09200D, C525S09200D, C525S09200D, C525S09200D, C525S090000, C525S091000
Reexamination Certificate
active
06331589
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to compositions comprising organic polymers and diblock copolymers of polyethylene or polystyrene and a polysiloxane such as polydimethylsiloxane which are incorporated as melt processing aids.
BACKGROUND OF THE INVENTION
It has long been known that organo polysiloxanes may be incorporated into organic polymer compositions to modify the processing characteristics thereof. For example, it is known that extrudability and calendering of such materials may be improved by incorporating therein liquid dimethylpolysiloxanes. U.S. Pat. No. 3,691,257 describes the addition of polystyrene-polydimethylsiloxane-polystyrene triblock copolymers to organic polymers in order to beneficially modify the surface properties of organic polymers and compositions containing them.
SUMMARY OF THE INVENTION
The present invention provides organic polymers and compounds containing such polymers which have enhanced melt processing characteristics. A composition of the present invention includes at least one organic polymer and from 0.1 percent by weight to 5, preferably 0.5 to 3.0, percent by weight of a diblock copolymer of polystyrene and a polysiloxane or polyethylene and a polysiloxane. The copolymers of this invention should have a polysiloxane content of from 20 to 90, preferably 40 to 75, percent by weight. The overall weight average molecular weight of the diblock copolymer ranges from 500 to 50,000, preferably 1000 to 25,000. The weight average molecular weight of the polydimethylsiloxane block may range from 500 to 40,000. The weight average molecular weight of the polyethylene block may range from 500 to 10,000 and the weight average molecular weight of the polystyrene block may range from 4000 to 30,000.
The organic polymer incorporating the above-described melt processing aid can be incorporated into a compound of the organic polymer and another polymer and/or an oil and/or a filler material. For example, block copolymers of styrene and butadiene or isoprene may constitute the organic polymer of the compound wherein the other polymeric material may be polypropylene, polyethylene, ethylene/propylene copolymers, and polystyrene, and the composition may or may not include oil or a filler material. Such compositions may contain 100 parts by weight of one organic polymer, 8 to 50 parts by weight of a second organic polymer, and 20 to 200 parts of an oil.
DETAILED DESCRIPTION OF THE INVENTION
The melt processing aids of this invention may be used to advantage with a wide variety of organic polymers and compounds containing those polymers. The organic polymer of the present invention may comprise any organic polymer or composition containing an organic polymer which is susceptible to the incorporation therein of the diblock copolymers of the present invention. The organic polymer may, for example, be a thermoplastic such as polyolefins (for example polyethylene, polypropylene, polybutylene, copolymers of ethylene and propylene or other alpha olefins such as butylene, hexane, octene, etc.) polyamides, polyethylene-terphthalate, polyvinylchloride, polyvinylidenechloride, polystyrene, and polymethylmethacrylate, an organic rubber, for example natural rubber, polyisoprene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, polycarbonate, polyacetal, polyphenylene sulfide, cyclo-olefin copolymers, styrene-acrylonitrile copolymer, ABS, styrene-maleic anhydride copolymers, chloroprene polymers, and isobutylene polymers, and cellulosic compounds such as cellulose acetate and cellulosic butyrate.
The most highly preferred organic polymers for use herein are block copolymers of a vinyl aromatic hydrocarbon such as styrene and a conjugated diene such as butadiene or isoprene, particularly triblock copolymers such as polystyrene-polybutadiene-polystyrene or polystyrene-polyisoprene-polystyrene. These polymers may be hydrogenated or unhydrogenated. Other preferred polymers for use herein are polyolefin polymers made using metallocene catalysts including ethylene-octene copolymers (such as Affinity® polymers made by Dow and Engage® polymers made by Dupont-Dow) ethylene-hexene copolymers, and ethylene-butene copolymers (such as Exact® polymers made by Exxon).
Polysiloxane block copolymers and methods of making them are fully described in U.S. Pat. No. 5,618,903, which is herein incorporated by reference. In block copolymerization of linear polystyrene-polydimethylsiloxane polymers, for example, 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.
In general, when solution anionic techniques are used, polymers of anionically polymerizable monomers are prepared by contacting the monomer to be polymerized simultaneously or sequentially with an anionic polymerization initiator such as Group IA metals, their alkyls, amides, silanolates, naphthalides, biphenyls and anthracenyl derivatives. It is preferable to use an organo alkali metal (such as sodium or potassium) compound in a suitable solvent at a temperature within the range from −150° C. to 300° C. preferably at a temperature within the range from 0° C. to 100° C. Particularly effective anionic polymerization initiators are organo lithium compounds having the general formula:
RLi
n
wherein R is an aliphatic, cycloaliphatic, aromatic or alkyl-substituted aromatic hydrocarbon radical having from 1 to 20 carbon atoms; and n is an integer of 1-4.
In general, any of the solvents known in the prior art to be useful in the preparation of such polymers may be used. Suitable solvents, then, include straight- and branched-chain hydrocarbons such as pentane, hexane, heptane, octane and the like, as well as, alkyl-substituted derivatives thereof; cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane and the like, as well as, alkyl-substituted derivatives thereof; aromatic and alkyl-substituted derivatives thereof; aromatic and alkyl-substituted aromatic hydrocarbons such as benzene, naphthalene, toluene, xylene and the like; hydrogenated aromatic hydrocarbons such as tetralin, decalin and the like; linear and cyclic ethers such as methyl ether, methyl ethyl ether, diethyl ether, tetrahydrofuran and the like.
Ethylene may be polymerized as described above with the addition that it is usually best to include a promoter, such as a diamine, to facilitate the reaction. Examples of these amines which include but are not limited to follow: N,N,N′,N′-tetramethylmethylenediamine (TMMDA), N,N,N′,N′-tetramethylethylenediamine (TMEDA), N,N,N′,N′-tetraethylethylenediamine (TEEDA), N,N,N′,N′-tetramethyl-1,3-propanediamine (TMPDA), N,N,N′,N′ tetra-methyl-1,4-butanediamine (TMBDA), dipiperidinomethane (DIPIM), 1,2dipiperidinoethane (DIPIE), 1,8-bis(dimethylamino)naphthalene, N,N,N′,N′ tetramethyl-o-phenylenediamine (TMOPDA), 1,2-dipyrolidinoethane (DIPIP), 1,3dipiperidinopropane (DIPIP), 1,2-bis(2.6-dimethylpiperidino)cyclohexane (BDMPC), sparteine, and the like.
The ethylene polymerization reaction can be carried out at 0° C. to 100° C. preferably 25° C. to 60° C. The ethylene pressure can be from 10 psig to 1000 psig, preferably 100 to 500 psig, The polymerization time can run from 10 minutes to 2 hours, preferably 30 minutes to 1 hour.
When the polymerization of the ethylene is complete, living polyethylene blocks are present in the polymerization mixture. These are perfectly linear polyethylene-alkyllithiums. These living polyethylenes can then be reacted isoprene or styrene or with cyclic siloxane monomers including those of the formula (R
1
R
2
SiO)
n
, where n=3-10, R
1
and R
2
=alkyl (C
1
-C
20
), alkenyl (C
2
-C
20
), hydrogen, benzyl or phenyl (including alkyl substituted aromatics and polycyclics) and R
1
and R
2
can
Kraton Polymers U.S. LLC
Mullis Jeffrey
LandOfFree
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