(under subclass 544) Subject matter comprising at least in part, a nonfibrous, nonparticulate material which contains tiny openings, often microscopic, through which certain fluids may pass. Generally the pore opening is of such irregular direction and small dimension that light will not pass through the porous component without distortion or diffusion.
(1) Note. An originally porous material, the pores of which have been filled, is not considered to be porous.
SEE OR SEARCH THIS CLASS, SUBCLASS:
155, for a nonmetallic* sheet, web or component which contains crevices of relatively small lateral dimensions extending thereto, but not therethrough.
158+, for a nonmetallic* sheet or web varying in thickness and having a foamed or cellular component.
304+, for a nonmetallic* sheet or web with a second component that is either porous or cellular. See especially subclasses 310+ for foamed or expanded material.
539.5, for the product which results when a metal or nonmetal composition, having an interconnected void structure, is impregnated with a nonmetal or metal composition, respectively, in a fluent form. 546+, for stock-material* of or containing consolidated metal powder, which materials often are porous, especially subclass 550 for such materials specified as having a porous component.
596, for stock-material having apertures, that is, openings which generally permit the passage of undiffused light.
605, for fibrous masses which generally are porous.
SEE OR SEARCH CLASS
51, Abrasive Tool Making Process, Material, or Composition,
296, for a tool making process or composition involving pore-forming.
75, Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,
228+, for consolidated metal powder compositions, which compositions often are porous.
106, Compositions: Coating or Plastic,
601+, for porous articles comprising alkali metal silicate; subclasses 672+ for porous cement, slag, and plaster compositions; and subclass 122 for porous organic compositions within the class (106) definition.
164, Metal Founding, 79, for a process of that class employing a pore-forming agent.
429, Chemistry: Electrical Current Producing Apparatus, Product and Process,
145, for a battery separator having plural layers of defined porosity.
