| 摘要 |
<p>Unsaturated polyester resins are homopolymerized or copolymerized with an ethylenically unsaturated comonomer using as catalyst 3,5 - dimethyl - 3,5 - dihydroxy - 1,2 - peroxycyclopentane. The peroxycyclopentane is employed as a paste or liquid composition in an organic liquid selected from alkanols, glycols, ethers, ketones, esters, heterocyclic amides and heterocyclic alcohols. Mixtures of two or more of such liquids may be present and water is also preferably present. Conventional metal activators and inhibitors may be present. In the examples, an unsaturated polyester formed from maleic and phthalic anhydrides and propylene glycol is copolymerized with styrene, in the presence of hydroquinone, using (a) the peroxycyclopentane, water, N - methyl-2-pyrrolidinone and triethyl phosphate; (b) cobalt naphthenate plus (a); (c) the peroxycyclopentane, water and N-methyl-2-pyrrolidone; and (d) the peroxycyclopentane, water and "Cellosolve" (R.T.M.) acetate. In (c) and (d) glass fibre laminates are formed. Two component systems comprising (i) resin + promoter, and (ii) the peroxide catalyst system may be formed.ALSO:A stable solution of 3,5-dimethyl-3,5-dihydroxy - 1,2 - peroxycyclopentane is formed by using as solvent an organic liquid selected from alkanols, glycols including ether glycols, ethers, ketones, esters, heterocyclic amides and heterocyclic alcohols. Mixtures of two or more of such liquids may be used and water is preferably also present. Instead of a solution a paste may be formed by dispersing solid peroxycyclopentane in the organic liquid which is preferably a phthalate ester. The concentration of the peroxycyclopentane is preferably such that the formulation has an active oxygen content of from 1 to 6% by weight. Preferably at least part of the solvent is an N-alkyl-2-pyrrolidone in which the alkyl group contains 1 to 4 carbon atoms. Other preferred solutions are those in which at least part of the organic solvent is a propylene glycol or tetrahydrofurfuryl alcohol. Phosphate esters such as triethyl phosphate are preferably added to increase the burning resistance.</p> |
