Method of making compressed sponges

• US 2,659,935 A
• Filed: 03/18/1950
• Issued: 11/24/1953
• Est. Priority Date: 03/18/1950
• Status: Expired due to Term

• Current Assignee: George Hammon Henry
• Original Assignee: George Hammon Henry
• Inventors: GEORGE HAMMON HENRY
• Application Number:
  US03/150,418
• Time in Patent Office: 1,347 Days
• US Class Current: 264/321
• CPC Class Codes: B29C 43/003 characterised by the choice of material
• CPC Class Codes: B29K 2105/04 cellular or porous
• CPC Class Codes: C08J 2329/00 Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Derivatives of such polymer
• CPC Class Codes: C08J 9/36 After-treatment C08J9/22 takes precedence

Claims

1. THE METHOD OF MAKING A COMPRESSED SPONGE WHICH COMPRISES PROVIDING A POLYVINYL FORMAL SPONGE HAVING INTERCONNECTED PORES THROUGHOUT, PREPARED FROM POLYVINYL ALCOHOL AND HAVING FROM 35 TO 80% OF THE HYDROXYL GROUPS OF THE ALCOHOL REACTED, SAID SPONGE CONTAINING NOT MORE THAN ABOUT 3% WATER, AND COMPRESSING SAID SPONGE UNDER A PRESSURE SUFFICIENT TO REDUCE MATERIALLY THE BULK OF SAID SPONGE, SAID SPONGE BEING MAINTAINED DURING THE COMPRESSING STEP AT A TEMPERATURE LESS THAN THAT AT WHICH THE SPONGE ASSUMES A PERMANENT SET.