Other

Exxon Research and Engineering Company

The Dow Chemical Company

Nordson Corporation

Chan I Chung

Laurence B Saidman

Walter H Cobbs, Jr

Robert A Barr

Robert J Huddleston

Miao Yong Cao

A novel barrier screw scientifically designed with new structural features that eliminate the shortcomings of the previous barrier screws and further improve their performance. The important new structural features include a structure of originating the barrier flight without creating any dead-spot while maintaining a constant solid channel width, a structure of terminating the barrier flight without creating any dead-spot while assuring good melt quality, a melt channel structure of avoiding excessively deep channel depth while assuring sufficient melt conveying capacity, and a solid channel structure of avoiding excessively large channel area with shallow channel depth while assuring good melt quality.

Scientifically designed barrier screw

A new class of binders for binding finely divided inert inorganic molding particles when shaped into objects by known mechanical shaping techniques such as injection molding. The novel binders are solid polymer solutions containing a major fraction of a low molecular weight solid relatively non-volatile chemical as solvent in which is substantially dissolved a minor fraction of at least one high molecular weight solid polymer. The solid polymer solution binders when molten are homogeneous solutions and can be readily uniformly mixed with the usual inorganic molding particles into a readily flowable mixture which can be shaped and solidified. When solidified, the polymer and solid chemical remain a substantially homogeneous solution without appreciable phase separation. The solid chemical fraction can be eliminated from the solid object by selective solvent extraction, leaving the solidified polymer fraction essentially undisturbed as a porous matrix for the molding particles so that the shape of the object is faithfully preserved. The resultant porous body can be used as is or have the remaining polymer fraction eliminated, if desired, e.g. by thermal decomposition of the polymer, to obtain a shaped part of the inert inorganic material ready, if desired, for sintering. A coupling agent, such as a plastic or other additive, may be included to improve binder-particle adhesion.

Solid polymer solution binders for shaping of finely-divided inert

The processibility during fabrication of a vinyl chloride polymer is improved by reducing the melt viscosity of the polymer when heated for shaping, by the admixture therewith of a small amount up to about 5% by wt of at least one melt-compatible normally crystalline solid solvent as a processing aid. At temperatures below the melting point of the solid solvent and the glass transition temperature of the polymer, the solid solvent deposits within the solid polymer as microdispersed solid microparticles which do not significantly adversely affect the mechanical properties of the solid polymer, whereas upon heating above the melt temperature of the mixture, the molten solid solvent is compatible with the molten polymer thereby effectively reducing its melt temperatures and melt viscosity during processing. Solid solvents found suitabe for vinyl chloride polymers are saturated carboxylic acids and their low molecular weight derivatives which have a crystalline melting point of at least about 80.degree. C., preferably about 100.degree. C., but not higher than about 180.degree. C. and do not exert substantial permanent solvent effect on PVC. The solid solvent can be mixed directly with the polymer or via a carrier polymer containing the same.

Solid solvents for improved processing of vinyl chloride polymers

This invention involves polyethylene blends prepared by a particular method to achieve a unique solid state processability. More specifically, the polyethylene blends of this invention are high density polyethylenes (HDPE) blended in solution with a minor fraction of branched low density polyethylene, linear low density polyethylene or other polyethylene copolymers with a melting point significantly lower than that of HDPE. The HDPE blends described herein possess a unique large scale deformation characteristics below the melting pointing of the major HDPE component, such that the HDPE blends are suitable for solid state processing such as stamping or forging, etc.

Solid state processing of polymer blends

The present invention relates to compositions and methods for reducing the melt viscosity of vinylidene chloride containing polymers having a majority of polymerized vinylidene chloride. The methods involve introducing a solid solvent into a vinylidene chloride containing polymer. The solid solvent is compatible with vinylidene chloride containing polymers at a processing temperature above the solid solvent melting point and will reduce the melt viscosity and improve processing of the vinylidene chloride containing polymer. Upon cooling below the solid solvent melting point the solid solvent will beocme microdispersed in the vinylidene chloride containing polymer with little or no solid solvent remaining dissolved in the vinylidene chloride containing polymer. One such solid solvent is dimethyl sulfone. The solid solvents are introduced into the vinylidene chloride containing polymer directly, or indirectly through the use of a polymer or additive containing the solid solvent which is blended into the vinylidene chloride containing polymer.

Dimethyl sulfone as a solid solvent for vinylidene chloride containing

Polymer materials having viscosities ranging from about 50,000 up to above 1,000,000 centipoises are mixed with a gaseous foaming agent to provide a polymer/gas solution under pressure such that when the polymer/gas solution is subsequently dispensed at atmospheric pressure the gas is released from the solution and becomes entrapped in the polymeric material to form a homogeneous polymer foam. Mixing is accomplished by force feeding the gas and polymeric material into and through a low energy input disk mixer with a low pressure drop across the mixer such that premature foaming or reaction of the polymeric material is avoided. The disk mixer includes a tubular housing, one or more driven shafts extending along the length of the housing, and a series of disks spaced along the shafts. The foaming gas enters into solution in the polymer in the compartments between the rotating disks. The process is characterized in that relatively high viscosity polymeric materials are mixed with gas and foamed with relatively low horsepower requirements, high throughput and low temperature rise of the polymer from conversion of the work of mixing to heat.

Method and apparatus for foaming high viscosity polymer materials

Extruders are widely used to transform solid plastic materials into molten plastic materials. Because of the low thermal conductivity of plastic materials and the inefficient mixing of the plastic materials inside an extruder, the heat is not evenly distributed in the material being processed and some portion of the material emerges from the extruder with excessive heat. This invention discloses a new screw with a novel mixing section which promotes mixing of the hot, molten material with the cold, unmolten material inside the screw channel by its unique geometry, thereby improving the heat transfer from the hot, molten material to the cold, unmolten material and increasing the energy efficiency of the extruder.

Energy efficient extruder screw

This invention relates to heterogeneous elastomeric blends having improved rheological properties of a major portion of a neutralized sulfonated elastomeric polymer with a minor portion of a polystyrene thermoplastic resin or a neutralized sulfonated polystyrene resin and mixtures thereof. Both the sulfonated elastomeric polymer and the sulfonated thermoplastic resin have about 0.2 to about 10.0 mole percent of SO.sub.3 H groups, at least 90% of which are neutralized with an organic amine.

Elastomer blend composition of a sulfonated EPDM terpolymer and a

An extruder screw for plastic extruding apparatus effects continuous separation of the molten plastic from the unmolten plastic with minimal interference with the flow of the plastic material being processed. Optionally, means are provided for additional mixing and homogenization of the molten plastic.

Growing community of inventors

Schenectady, NY, United States of America

Chan I Chung