| 摘要 |
Water-resistant protein plastics are prepared by modifying a protein with formaldehyde and a mononuclear aromatic monocarboxylic acid, 2-15 parts of said acid being used per 100 parts of protein. The protein may be rennet or lactic casein, soya bean glycinin, peanut protein, hordein, gliadin or zein, and formaldehyde solution, formaldehyde polymers or compounds liberating formaldehyde with heating or catalysts may be used. Casein may be blended with the acid in an edge runner mill, formed, immersed in formaldehyde, and dried. With prolamines such as zein, it is preferred to blend with a plasticizer the acid, and paraformaldehyde, and then form. The preferred acids include cumic, salicylic, acetyl salicylic, m- and p-hydroxy benzoic, benzoic, o-chlorbenzoic, o-, m-, and p-toluic, cinnamic, and 3,5-dinitrobenzoic acids. In examples: (1) rennet casein is mixed with water and benzoic acid and extruded into rods which are treated with 5 per cent formaldehyde or, after air exposure, repressed into sheets which are formaldehyde treated; (2) casein is blended with cumic acid, pressed into sheets, and hardened; (3) ground nut protein is blended with benzoic acid, paraformaldehyde, and water, and pressed into sheets.
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