| 摘要 |
<p>Weakly crosslinked polyacrylic acid powder is prepd. by the pptn. polymerisation of 50-250 g/l acrylic acid in a mixt. of non-aromatic solvents, in the presence, w.r.t. acrylic acid, of 0.7-3.5 wt.% crosslinking monomer and of 0.05-1 wt.% radical -former, at 40-90 deg.C. Novelty consists in using a solvent mixt. contg., by vol., (1) 80-90% cyclohexane or an aliphatic satd. 1-5C hydrocarbon contg. 1-4 Cl and (2) 1-20% n-propanol, a satd. aliphatic 4-6C monohydric alcohol, a 3-6C aliphatic satd. carboxylic acid ester or MeEtCO. The prods. can be used in the prepn. of (i) pharmaceutical and cosmetic compsns., esp. clear gels, and also ointments and emulsions, (ii) printing pastes, e.g. for textiles and (iii) as thickeners for flooding water in sec. petroleum extn. The polyacrylic acids have improved thickening activity and their gels have increased clarity and reduced graininess.</p> |
