US PATENT SUBCLASS 521 / 56
.~.~ Particle which is expandible, process of preparing an expandible particle, or process of expanding a particle 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}
56.~.~ Particle which is expandible, process of preparing an expandible particle, or process of expanding a particle to form a cellular product {4}
57  DF  .~.~.~> Including step of surface coating a particle or process of expanding a surface coated particle
58  DF  .~.~.~> Expanding utilizing plural expansion steps
59  DF  .~.~.~> Expandible system contains two or more solid polymers or at least one solid polymer and at least one polymer-forming system
60  DF  .~.~.~> Adding expanding agent subsequent to solid polymer formation

DEFINITION

Classification: 521/56

Particle which is expandable, process of preparing an expandable particle, or process of expanding a particle to form a cellular product:

(under subclass 50) Subject matter wherein a cellular product is produced from a particle.

(1) Note. This subclass provides (1) for processes of

forming a cellular product from an expandable particle; (2) for a particle which is claimed as being capable of forming a cellular product; or (3) for processes of preparing a particle which is capable of being formed into a cellular product.

(2) Note. This subclass does not require that the continuous phase of the particle be a solid synthetic polymer. It is sufficient if the particle merely contains a solid synthetic polymer.

(3) Note. This subclass requires that the particle nature be retained in the final cellular product and not be destroyed during or prior to the cell-forming step, e.g., melting particles for extruding is excluded herefrom, etc.

(4) Note. This subclass includes the process of treating a preexpanded particle so as to subsequently expand said particle.

(5) Note. Also search appropriate subclasses for a sintering sheet having structure insufficient for placement into Class 428.

SEE OR SEARCH THIS CLASS, SUBCLASS: 79, for processes of forming a cellular product from particles which are either completely or partially melted during extrusion. The term "extrusion", per se, connotes destruction of the particulate structure unless the disclosure indicates to the contrary.

82+, for forming a cellular product from bulk handled particulate material whose particulate nature is destroyed prior to or during the cell-forming step.

SEE OR SEARCH CLASS

264, Plastic and Nonmetallic Article Shaping or Treating: Processes, for a process of agglomerating or sintering wherein a sheet product may be formed having voids therein.

427, Coating Processes, for processes involving more than the mere coating of a particulate material and wherein said particulate material is nonexpendable.

428, Stock Material or Miscellaneous Articles, for mere processes of coating and for coated particles which are non-expandable.