Plasticized sponge material and method of making same

• US 2,664,366 A
• Filed: 09/19/1949
• Issued: 12/29/1953
• Est. Priority Date: 09/19/1949
• Status: Expired due to Term

• Current Assignee: Lumley Wilson Christopher
• Original Assignee: Lumley Wilson Christopher
• Inventors: LUMLEY WILSON CHRISTOPHER
• Application Number:
  US03/116,642
• Time in Patent Office: 1,562 Days
• US Class Current: 15/244.4
• CPC Class Codes: C08J 2329/14 Homopolymers or copolymers of acetals or ketals obtained by polymerisation of unsaturated acetals or ketals or by after-treatment of polymers of unsaturated alcohols
• CPC Class Codes: C08J 9/40 Impregnation

Claims

1. THE METHOD OF MAKING A SOFT, RESILIENT SPONGE MATERIAL HAVING INTERCONNECTED PORES BY REACTING POLYVINYL ALCOHOL AND FORMALDEHYDE, WHICH COMPRISES:

PROVIDING AN AQUEOUS SOLUTION OF FORMALDEHYDE, POLYVINYL ALCOHOL CONTAINING LESS THAN 10% RESIDUAL HYDROLYZABLE MATERIAL IN THE MOLECULE, AN ACID CATALYST IN WHICH THE ACID FUNCTIONAL GROUP IS INORGANIC AND HAVING A DISSOCIATION CONSTANT OF AT LEAST 10-2 AND A FROTHSTABILIZING WETTING AGENT SOLUBLE IN AND SUBSTANTIALLY STABLE TO SAID SOLUTION;

FORMING A SUBSTANTIALLY STABLE AND HOMOGENEOUS FROTH WITH SAID SOLUTION STABILIZED WITH THE WETTING AGENT;

REACTING THE POLYVINYL ALCOHOL AND FORMALDEHYDE IN THE SOLUTION THEREBY CAUSING GELLATION AND SOLIDIFICATION OF THE FROTH WITH THE PRODUCTION OF INTERCONNECTED PORES SIMULTANEOUSLY WITH THE PROGRESSION OF THE REACTION, THE FROTH BEING FORMED PRIOR TO APPRECIABLE REACTION BETWEEN THE POLYVINYL ALCOHOL AND THE FORMALDEHYDE;

STOPPING SAID REACTION WHEN APPROXIMATELY 35-80% OF THE HYDROXYL GROUPS OF THE POLYVINYL ALCOHOL HAVE BEEN REACTED WITH THE FORMALDEHYDE;

WHEREBY A SPONGE MATERIAL IS FORMED IMPREGNATING SAID SPONGE WITH AN AQUEOUS SOLUTION OF A POLYHYDRIC ALCOHOL AND THEN REMOVING EXCESS OF SAID SOLUTION UNTIL THERE REMAINS DEPOSITED ON SAID SPONGE ABOUT 20-100% OF SAID POLYHYDRIC ALCOHOL BASED ON THE DRY WEIGHT OF THE SPONGE.