摘要:
Novel processes and compositions are provided for the preparation of foamed, crosslinked polyethylene utilizing cyclic peroxyketal crosslinking/blowing agents. The novel compositions include esters of thiodipropionic acid as activators.
摘要:
Gem-diperoxyesters of the formula: ##STR1## where R is selected from methyl and ethyl; R.sub.1 is ethyl when R is ethyl; R.sub.1 is hydroxyalkyl of 1 to 7 carbon atoms when R is methyl; and each R.sub.2 is ##STR2## where each of R.sub.3, R.sub.4, and R.sub.5 is selected from hydrogen and alkyl, provided not more than one of R.sub.3, R.sub.4, and R.sub.5 is hydrogen, R.sub.3, R.sub.4, and R.sub.5 collectively containing from 2 to 12 carbon atoms.The compounds are particularly efficient at varying temperatures from ambient to 60.degree. C. for the initiation of the polymerization of vinyl chloride. They also have high efficiency in the curing of polyester resins and in the polymerization of other monomers and comonomers having ethylenic unsaturation.
摘要:
Unsaturated polyester resin foams or cellular structures of varying low densities are prepared quickly at ambient temperatures from an admixture which comprises a liquid unsaturated curable polyester resin, an organic isocyanate compound, a suitable surfactant, an accelerator and a particular combination of peroxide curing agents, which also serves to initiate the release of gases that permit expansion of the resin in a controlled manner to obtain a foamed structure.
摘要:
Gem-diperoxyesters of the formula: ##STR1## where R is selected from methyl and ethyl; R.sub.1 is ethyl when R is ethyl; R.sub.1 is hydroxyalkyl of 1 to 7 carbon atoms when R is methyl; and each R.sub.2 is ##STR2## where each of R.sub.3, R.sub.4, and R.sub.5 is selected from hydrogen and alkyl, provided not more than one of R.sub.3, R.sub.4, and R.sub.5 is hydrogen, R.sub.3, R.sub.4, and R.sub.5 collectively containing from 2 to 12 carbon atoms.The compounds are particularly efficient at varying temperatures from ambient to 60.degree. C. for the initiation of the polymerization of vinyl chloride. They also have high efficiency in the curing of polyester resins and in the polymerization of other monomers and comonomers having ethylenic unsaturation.
摘要:
High density polyethylene is cross-linked with certain cyclic perketals including a group of novel cyclic perketals. Typical of the novel molecules is 3,6,6,9,9-pentamethyl-3-ethylacetate-1,2,4,5-tetraoxy cyclononane.
摘要:
High density polyethylene is cross-linked with certain cyclic perketals including a group of novel cyclic perketals. Typical of the novel molecules is 3,6,6,9,9-pentamethyl-3-ethylacetate-1,2,4,5-tetraoxy cyclononane.
摘要:
Acyl peroxycarbonic esters of the formula ##STR1## in which R is methyl or ethyl, R' is alkyl, and R and R' together have 17 or more carbon atoms. The compounds have unusual thermal stability, together with improved polymerization initiating efficiency. Particularly outstanding efficiency is found in connection with the polymerization of methyl methacrylate.
摘要:
Acyl peroxycarbonic esters of the formula ##STR1## in which R is methyl or ethyl, R' is alkyl, and R and R' together have 17 or more carbon atoms. The compounds have unusual thermal stability, together with improved polymerization initiating efficiency. Particularly outstanding efficiency is found in connection with the vulcanization of silicone rubber.
摘要:
Acyl peroxycarbonic esters of the formula ##STR1## in which R is methyl or ethyl, R' is alkyl, and R and R' together have 17 or more carbon atoms. The compounds have unusual thermal stability, together with improved polymerization initiating efficiency. Particularly outstanding efficiency is found in connection with the curing of polyester resins.
摘要:
Acyl peroxycarbonic esters of the formula ##STR1## in which R is methyl or ethyl, R' is alkyl, and R and R' together have 17 or more carbon atoms. The compounds have unusual thermal stability, together with improved polymerization initiating efficiency. Particularly outstanding efficiency is found in connection with the polymerization of methyl methacrylate.