| 摘要 |
<p>Plasticised vinyl acetate (co)polymer latex adhesive of setting time less than 10 secs., contg. 50-70 wt.% solids, is prepd. by aq. emulsion polymsn. of vinyl acetate opt. with other monomer(s) in the presence of PVA, and then opt. adding a plasticiser to the obtd. latex. The improvement is that the polymsn. medium whose pH is 2.5-6 contains water, 40-65 wt.% (w.r.t. medium) vinyl acetate or its mixt. with other monomers, 1-10 wt.% (w.r.t. monomers) chain regulator and 0.5-3 wt.% (w.r.t. monomers + chain regulator) PVA, and the plasticiser comprises 0-30 wt.% of the polymer formed. The vinyl acetate polymer has a particle size of 0.1-3 microns and its mol. wt. is 10,000-300,000. The adhesive sets rapidly and can therefore be used in high speed, automatic machines for bonding porous materials such as wood, paper and cardboard. It is partic. useful for the packaging industry.</p> |
