发明授权
US4332850A Vinyl acetate-ethylene emulsions for nonwoven goods 失效
醋酸乙烯酯 - 非织造布的乙烯乳液

Vinyl acetate-ethylene emulsions for nonwoven goods
摘要:
This invention relates to a vinyl acetate-ethylene copolymer containing emulsion particularly adapted for the preparation of nonwoven goods. The vinyl acetate-ethylene emulsion is prepared by an improved process for producing an aqueous emulsion suitably adapted for producing non-woven goods said emulsion containing a vinyl acetate-ethylene copolymer wherein said copolymer contains from about 75-96% by weight of vinyl acetate. It is produced by forming an aqueous suspension of vinyl acetate, ethylene, and stabilizer, initiating the polymerization of the reaction mixture by the addition of catalysts, and adding from about 0.5-10% by weight of the vinyl acetate of a crosslinkable monomer. The improvement for enhancing the absorptivity of the copolymer comprises:pressurizing the reactor with ethylene to an initial ethylene equilibrium pressure of from about 100 to 1,000 psig;initiating the reaction mixture by the addition of catalyst at a temperature from about 10.degree.-35.degree. C. and bringing the reaction mixture to a reaction temperature of from 45.degree.-85.degree. C. and operating pressure within a period of not more than 2 hours and the reaction temperature exceeds the initiation temperature by at least 20.degree. C.;adding the crosslinkable monomer at a substantially uniform rate such that the major portion of monomer has been added by the time the vinyl acetate content in the emulsion has been reduced to a level of from 3-25% by weight of the emulsion;andcontinuing polymerization of the reaction mixture until the vinyl acetate content in said emulsion is reduced below about 1% by weight.
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