US PATENT SUBCLASS 521 / 79
.~.~ Extruding a solid polymer containing material to form a cellular product

Current as of: June, 1999
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521 /   HD   SYNTHETIC RESINS OR NATURAL RUBBERS -- PART OF THE CLASS 520 SERIES

*  DD  SYNTHETIC RESINS (Class 520, Subclass 1) {3}
50  DF  .~ CELLULAR PRODUCTS OR PROCESSES OF PREPARING A CELLULAR PRODUCT, E.G., FOAMS, PORES, CHANNELS, ETC. {27}
79.~.~ Extruding a solid polymer containing material to form a cellular product {2}
80  DF  .~.~.~> Including solid polymer formation in or during extruding step
81  DF  .~.~.~> System contains a mixture of solid polymer or at least one solid polymer and at least one solid polymer-forming system

DEFINITION

Classification: 521/79

Extruding a solid polymer containing material to form a cellular product:

(under subclass 50) Subject matter drawn to processes of cell formation wherein said cell formation is achieved or initiated by a step of extrusion of a molten or liquid material from a region of high pressure through an orifice into a region of lower pressure.

(1) Note. Spinning, per se, is proper for this subclass as a specialized form of extrusion wherein a fiber or filament is produced.

(2) Note. Processes involving an extrusion step wherein cell formation and extrusion are incidental to one another, e.g., no cell formation initiated or achieved during the extruding step, etc., are not proper for this subclass.

(3) Note. For purposes of this subclass mere removal of material from a chamber by a step recited as "extrusion" is

not proper herein unless there is an intent to shape the removed material by the "extrusion step."

(4) Note. This subclass does not provide for compositions which are to be used in preparing a cellular product even if claimed as being extrudable, or for cellular products which are the result of an extruding procedure.

SEE OR SEARCH CLASS

264, Plastic and Nonmetallic Article Shaping or Treating: Processes, 41+, for processes of preparing a composite article wherein at least one member of the composite is of a porous nature; and subclasses 109+ for processes of bonding either cellular or noncellular particles of solid particles together so as to form a layer and wherein the solid particles may have voids between the bonded particles.