Patent GB-352140-A (GB)
Title: Improvements in and relating to synthetic resins and methods of manufacturing the same
IPC: C08G12/08
Filed: 1930-04-30
Abstract: Aldehyde-amine condensation products.-A fibrous pulp is added to the clear liquid resulting from the reaction of an aromatic amine such as aniline benzidine or diphenylamines and an excess of an aldehyde such as formaldehyde, acetaldehyde or furfural in acid solution at a rising temperature not exceeding 40 DEG  C. the whole being stirred or beaten, the acid being then neutralized to precipitate the resin and the temperature then being increased to flocculate the resin particles with or without the previous washing out of the salts.  The process may be effected in apparatus suitable for paper manufacture. Sheets produced from this mixture adhere together under heat and pressure.  In an example aniline and formaldehyde are condensed with hydrochloric acid in a paper beater and paper pulp is added to the clear liquor; the stock is diluted with water and lime is added, for instance to pH = 8,2, and the temperature is raised to 60 DEG  C. to flocculate the resin, beating being continued.  The stock is then diluted to 1 per cent and fed to the paper machine, the sheets being dried and calendered.  The sheets may be pressed at 150 DEG  C. and 1000 lbs. pressure or more.  Pulp other than cellulose pulp can be used if desired, and fibrous and/or non-fibrous fillers may be added, such as wood-flour, asbestos, clay or mica.  A suitable composition is kraft fibre 32 parts, mica 36 parts and resin 32 parts, but the resin content may be as high as 50 per cent.  The material prepared as above described may be used for the production of insulating tapes, slot insulating materials for dynamo-electric machines, transformer spacers, non-metallic gears, refrigerator strips for refrigerator doors and the like. Specifications 247,957, 266,358, [both in Class 2 (iii), Dyes &c.], and 342,326 are referred to.ALSO:A fibrous pulp is added to the clear liquid resulting from the reaction of an aromatic amine such as aniline, benzidine, or diphenylamine, and an excess of an aldehyde such as formaldehyde, acetaldehyde, or furfural in acid solution at a rising temperature not exceeding 40 DEG  C. the whole being stirred or beaten, the acid being then neutralized to precipitate the resin, and the temperature then being increased to flocculate the resin particles, with or without the previous washing out of the salts. The process may be effected in apparatus suitable for paper manufacture.  Sheets produced from this mixture adhere together under heat and pressure.  In an example aniline and formaldehyde are condensed with hydrochloric acid in a paper beater, and paper pulp is added to the clear liquid; the stock is diluted with water and lime is added, for instance to pH = 8,2, and the temperature is raised to 60 DEG  C. to flocculate the resin, beating being continued.  The stock is then diluted to 1 per cent, and fed to the paper machine, the sheets being dried and calendered. The sheets may be pressed at 150 DEG  C. and 1000 lbs. pressure or more. Pulp other than cellulose pulp can be used if desired, and fibrous and/or non-fibrous fillers may be added, such as wood-flour, asbestos, clay or mica.  A suitable composition is kraft fibre 32 parts, mica 36 parts, and resin 32 parts, but the resin content may be as high as 50 per cent.  The material prepared as above described may be used for the production of insulating tapes, slot insulating materials for dynamo-electric machines, transformer spacers, non-metallic gears, refrigerator strips for refrigerator doors and the like.  Specifications 247,957, 266,358, [both in Class 22, Cements &c.], and 342,326 are referred to.