Mobil Oil Corporation

Basf Corporation

Binnur Z Gunesin

Paul A Pindris

James G Murray

Frederick C Schwab

Alex W Kawczak

Allan B Furtek

Viren P Trivedi

Patricia J Nelson

Ronald J Gustafson

An anionic dispersion polymerization process is described for preparing linear block copolymers containing an odd number of blocks including blocks of polymerized styrenic compound, e.g., styrene, (A blocks) which are the end or terminal blocks of the polymer and which alternate along the polymer chain with elastomeric blocks of polymerized conjugated diene units (B blocks). The process includes initially contacting the total amount of styrenic compound to be utilized in forming the block copolymer under polymerization conditions with an anionic initiator and dispersant in an inert dispersion medium in which the polymer is insoluble and carrying out the process in stages wherein less than the total amount of styrenic compound is allowed to polymerize, alternating with stages wherein amounts of diene are added and allowed to polymerize completely. The addition of diene interrupts the polymerization of styrenic compound due to the greater tendency of diene to polymerize.

Block copolymer process

Butadiene is polymerized alone or with a monomer such as styrene in a dispersion in propane, butane or its mixtures with minor amounts of other C.sub.4 -C.sub.6 alkanes, e.g., n-pentane and a dispersant which is preferably a hydrogenated styrene/ conjugated diene block copolymer to achieve stable dispersions at higher solids and butadiene levels possible with similar alkane dispersants.

Process of dispersion polymerization of butadiene in propane or butane

Supported olefin, e.g., alpha-olefin, polymerization catalyst compositions, such as Ziegler-Natta catalysts, are modified by using porous, polymer particles having an average pore diameter of at least about 10 .ANG. as the catalyst support. The resulting catalyst composition is more active than refractory oxide-supported catalysts and it is not susceptible to deactivation by catalyst poisons, such as oxygen or water. Additionally, the polymer particles need not be calcined prior to the catalyst synthesis.

Particulate polymer-supported olefin polymerization catalyst

Butadiene is polymerized alone or with a monomer such as styrene in a dispersion in propane, butane or its mixtures with minor amounts of other C.sub.4 -C.sub.6 alkanes, e.g., n-pentane and a dispersant which is preferably a styrene/hydrogenated isoprene block copolymer to achieve stable dispersions at higher solids and butadiene levels possible with similar alkane dispersants.

The viscosity of the dispersing medium, such as cyclohexane, in the anionic dispersion polymerization of monomers, such as styrene, is increased by adding a higher viscosity inert miscible liquid, such as hexadecane, or a soluble inert solid, or by using a liquid having a viscosity of greater than about 2 cp. The increased viscosity assists in the formation of dispersed polymer particles having a narrower particle size distribution than those produced in the lower viscosity dispersing medium.

Anionic polymerization in high viscosity dispersing medium to form

High molecular weight linear block copolymers containing 5 or more alternating blocks of (A) polymerized styrene or alkyl substituted styrene units, and (B) polymerized conjugated diene units, terminated by (A) units, are prepared by anionic dispersion polymerization to give clear polymers having excellent physical properties.

High impact, highly transparent linear styrene-diene block copolymers

Styrene or other anionically polymerizable monomer is anionically homopolymerized in a dispersion using a non-solvent, e.g., hexane using three or more stages to obtain spherical microparticles, e.g., 2-5 microns, with a narrow size distribution.

Multi-stage anionic dispersion homopolymerization to form microparticles

The impact strength of containers made from foams of aromatic olefins such as polystyrene and poly-(para-methylstyrene) is improved by the addition of a small amount e.g., 2 to 25 weight percent of a polyethylene such as linear low density polyethylene. Meat trays made of such foams can be processed in automatic packaging equipment and exhibit reduced damage, such as cracking, in processing.

Container made from polystyrene foams containing polyethylene

Crystalline isotactic poly(para-methylstyrene) previously unreported in the literature is prepared by polymerizing para-methylstyrene with a TiCl.sub.3 /aluminum alkyl catalyst and fractionating the product to obtain a crystalline fraction with a crystalline melting point of 205.degree. C.

Crystalline isotactic poly(para-methylstyrene)

The present invention provides a non-staining, non-sticking styrenic polymer containing a siloxane. The invention further provides a method for forming the styrene/siloxane copolymer blend.

Non-staining, non-sticking styrenic polymers

This invention provides a high molecular weight copolymer blend of polyethylene and poly(para-methylstyrene) in the absence of any compatibilizing agent. Preferably, the polyethylene is linear low density polyethylene.

P-methylstyrene polymer blends

The present invention provides a method for improving the environmental stress crack resistance of high impact poly(p-methylstyrene) by blending high impact poly(p-methylstyrene) with an additive copolymer having a higher environmental stress crack resistance. The invention further provides a shaped container resistant to fats.

High impact poly(p-methylstyrene) polymers

This invention provides a high molecular weight copolymer blend of polyethylene and poly(para-methylstyrene) or high impact poly(p-methylstyrene) in the presence of a hydrogenated compatibilizing agent, such as a hydrogenated butadiene diblock.

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New York, NY, United States of America

Binnur Z Gunesin