The Dow Chemical Company

Dow Global Technolgoies LLC

Gary C Welsh

Mehmet Demirors

Chau Van Vo

Edwin A Hallberg

Brian D Dalke

Michael Ballot

Peter Hendrikus Vollenberg

Jozef Julius Sleeckx

Roldolfo J Salmang

Eric K Lee

Michael M Ballot

The present invention is a process for producing a thermoplastic foam sheet comprising contacting a molten monovinylidene aromatic or olefinic polymer with a physical blowing agent to form a polymer/blowing agent mixture, and foaming the mixture into a region of lower pressure within a sheet extrusion line, wherein the extrudate is pulled and compressed to form a thermoplastic foam sheet having a uniform thickness.

Process for producing thermoformable foam sheet using a physical blowing agent

Monovinyl aromatic polymer compositions with high melt strength, good flow and good heat properties which are suitable for fast injection molding, blow molding and thermoforming applications, comprising non-linear monovinyl aromatic polymers and copolymers having comb-type structures with 3 branches, star type structures with 4 to 6 branches, and/or dendritic structures in which the branches themselves have attached branched units. These compositions possess inherent melt strength and can be blow molded or thermoformed without sagging or molded into articles in shorter cycle times using less material than linear monovinyl aromatic polymers and copolymers with the same flow and heat distortion temperatures. Also disclosed is a process for making high molecular weight branched monovinyl aromatic polymers, for example, Mw between 75,000 and 500,000, at high rates, comprising polymerizing pure styrene monomer or styrene monomer and polymerizable comonomer via a continuous free radial polymerization process using a peroxide initiator, for example, n-butyl tert-butyl peroxy fumarate, selected from a new class of vinyl peroxide initiators that contain both a copolymerizable double bond and an organic peroxide moiety.

Non-linear styrenic polymer compositions and articles prepared therefrom

An improved polystyrene foam having less corrugation is disclosed which uses carbon dioxide as the blowing agent and 1-30 weight percent endothermic agent, such as water, with the weight based on the total carbon dioxide blowing agent and endothermic agent weight. This combination of carbon dioxide and endothermic agent decreases the corrugation of the thermoplastic foam, while just slightly increasing density, when the process parameters, including throughput, are equivalent to using only carbon dioxide. The process an also allow an increased foaming temperature and greater process throughput of an equivalent density thermoplastic foam at approximately equivalent corrugation levels when compared to the use of only using only carbon dioxide.

Polystyrene foam and a process for making the same

The present invention is a styrenic polymer foam blown with solely carbon dioxide and a process for making that styrenic polymer foam. Foam sheet made by this process is especially useful for thermoforming purposes.

Polystyrene foam made with only carbon dioxide as a blowing agent and a

A rigid thermoformable packaging material is provided which includes an outer layer of a nonfoamed oriented polystyrene and an inner layer of a functional polymer resin. The laminated packaging material can be produced by either thermal lamination or coextrusion. The packaging material is readily thermoformed into containers for medical or dental products or foods and is heat sealable, tough, resistant to chemicals, and resistant to cracking and tearing during handling by thermoforming equipment.

Thermoformable laminated packaging material

A versatile, space-efficient rotary sheeter including a pair of roll assemblies synchronously driven and rotating at web speed. Each assembly carries cooperating revolving cutter rolls and backup slot rolls staggered on opposed supporting roll assemblies and being readily shiftable, through gearing, between time-controlled operative and inoperative phasing modes for conveniently converting a moving web of roll stock of sheet material into cut segments of selectable lengths. The apparatus is physically fixed in place during operation and operates without any need for an accumulation loop in the moving web. The sheeter is readily adjustable, easily maintained, and has enhanced safety features. It operates over a wide range of adjustable speeds to accommodate web stock of various compositions and thickness.

Growing community of inventors

Midland, MI, United States of America

Gary C Welsh