US PATENT SUBCLASS 521 / 61
.~.~ Process of preparing a cellular product by removal of material from a solid polymer-containing matrix without expanding the matrix; composition which is nonexpandible and is designed to form a cellular product by said process; or process of preparing said composition

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}
61.~.~ Process of preparing a cellular product by removal of material from a solid polymer-containing matrix without expanding the matrix; composition which is nonexpandible and is designed to form a cellular product by said process; or process of preparing said composition {3}
62  DF  .~.~.~> Mixture of solid polymers present during cell formation
63  DF  .~.~.~> Cellular product-forming process wherein the removable material is present or is produced in situ during the solid polymer formation step
64  DF  .~.~.~> Removing a liquid to form a cellular product

DEFINITION

Classification: 521/61

Process of preparing a cellular product by removal of material from a solid polymer- containing matrix without expanding the matrix; composition which is nonexpandible and is designed to form a cellular product by said process; or process of preparing said composition:

(under subclass 50) Subject matter wherein a cellular product is produced by removing a material from a polymeric composition containing a solid polymer and wherein removal is accomplished without the composition being expanded.

(1) Note. This subclass provides for (1) processes of forming a cellular product by removal of a material from a previously formed solid polymer composition; or (2) a solid polymer containing composition which is claimed as being capable of preparing a cellular product by removal of material therefrom; or (3) processes of preparing the composition of (2) above.

(2) Note. In general, the operations proper for this subclass are characterized as leaching, extracting, evaporation, etc.

(3) Note. Two step processes wherein an additional cell-forming operation is accomplished subsequent to the removal operation are proper herein unless an additional material is added subsequent to the removal which reacts with the polymer or forms a desired composition therewith.

(4) Note. Processes involving a temporary base wherein a polymeric composition is placed on a temporary base and where the base is merely used as a work holder and is subsequently removed after the cell-forming operation of the polymeric composition are proper for this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:

53+, for two-step processes (1) wherein an additional cell-forming operation is accomplished subsequent to the removal operation, and (2) an additional material is added subsequent to the removal which reacts with the polymer or forms a desired composition therewith.

SEE OR SEARCH CLASS 264, Plastic and Nonmetallic Article Shaping or Treating: Processes,

41+, for a process claim involving preparing a cellular article by removal of material from a sheet, film, or

oriented or stretched fiber. Terms in claims such as forming a "mass", "forming an article", "forming a desired shape", or "shaping in a mold to provide a product of desired shape" preparatory to the removal operation are considered insignificant process limitations and such claims are proper for Class 521.

427, Coating Processes, for a process of permanently coating a base and removing material from the coating, from the base, or from both, to produce a cellular product.