Process for preparing halogenated polymers
The invention concerns a process for the aqueous suspension, micro-suspension, emulsion or micro-emulsion polymerization of at least one halogenated monomer, in particular chlorinated, for example vinyl chloride, by itself or with one or more other vinyl monomers, preferably less than 50% by weight of one or more other vinyl monomers, in which at least one shortstopper and at least one perhalogenate, acting as a whitening agent, are added. The invention also concerns the use of an association of at least one shortstopper and at least one perhalogenate, acting as a whitening agent, in reactions for the polymerization of halogenated monomers. The invention further concerns compositions comprising at least one shortstopper and at least one perhalogenate.
1. Process for the aqueous suspension, micro-suspension, emulsion or micro-emulsion polymerization of at least one halogenated monomer by itself or with one or more other vinyl monomers, comprising adding at least one shortstopper and at least one perhalogenate, acting as a whitening agent.
2. Process according to claim 1 , wherein the polymerization is carried out in the presence of at least one polymerization initiator.
3. Process according to claim 1 , wherein the shortstopper is selected from phenolic derivatives and mono-alkyl-N- or dialkyl-N,N-substituted hydroxylamines, each alkyl radical containing 1 to 4 carbon atoms, as well as mixtures of two or more thereof in any proportions.
4. Process according to claim 1 , wherein the at least one perhalogenate is an organic or mineral perhalogenate selected from metallic perhalogenates, alkali metal or alkaline-earth metal perhalogenates.
5. Process according to claim 1 , further comprising initiating the polymerization with at least one polymerization initiator selected from dialkyl peroxydicarbonates, peroxy-tert-alkanoates, diacyl peroxides, and alkyl hydroperoxides.
6. Process according to claim 1 , wherein the polymerization comprises adding an initiation system comprising at least one compound selected from dialkyl peroxydicarbonates, peroxy-tert-alkanoates, diacyl peroxides and alkyl hydroperoxides and the at least one shortstopper, wherein the shortstopper comprises at least one of N-mono-alkylhydroxylamine or an N,N-dialkylhydroxylamine, and the at least one perhalogenate.
7. Process according to claim 1 , further comprising adding at least one thermal stability additive selected from the following thermal stabilizers or thermal co-stabilizers: 2-ethylhexylmercapto-acetic acid, thioglycolic acid, and esters thereof, alkali metal carbonates, β-diketones, epoxidized vegetable oils, phosphites, β-ketone esters, metallic salts or soaps, hydrazides, the mineral compounds hydrotalcites and zeolites, alcohols and polyols, glycidyl derivatives, a-phenylindole, compounds of the dihydropyridine type, enamines, and alkanolamine type derivatives, by themselves or as mixtures of two or more thereof, in any proportions.
8. A method of preparing a halogenated polymer or copolymer comprising adding at least one shortstopper and at least one perhalogenate.
9. The method according to claim 8 , wherein the shortstopper is selected from phenolic derivatives and mono-alkyl-N- or dialkyl-N,N-substituted hydroxylamines, each alkyl radical containing 1 to 4 carbon atoms.
10. The method according to claim 9 , wherein the shortstopper is selected from di-ethylhydroxylamine and 4-OH-Tempo (1,4-dihydroxy-2,2,6,6-tetramethylpiperidine), as well as mixtures of two or more thereof in any proportions.
11. Composition comprising at least one shortstopper and at least one perhalogenate.
12. Composition according to claim 11 , wherein the shortstopper is diethylhydroxylamine and the perhalogenate is sodium perchlorate.
13. Composition according to claim 11 , comprising:
5% to 40% by weight of diethylhydroxylamine;
5% to 40% by weight of sodium perchlorate;
optionally, up to 20% by weight of one or more stabilizers and/or co-stabilizers; and
the complement to 100% by weight of water.
14. Process according to claim 1 , wherein the at least one halogenated monomer is chlorinated.
15. Process according to claim 1 , wherein the at least one halogenated monomer comprises vinyl chloride.
16. Process according to claim 1 , wherein the one or more other vinyl monomers comprises less than 50% by weight.
17. Process according to claim 1 , wherein the at least one perhalogenate is chosen from alkali metal and alkaline-earth metal perchlorates.
18. Process according to claim 1 , wherein the at least one perhalogenate comprises sodium perchlorate.
19. Process according to claim 7 , wherein the at least one thermal stability additive is chosen from stearates, adipates, amino-uracil derivatives, and/or thio-uracil derivatives.
20. The method according to claim 8 , wherein the at least one perhalogenate comprises a metal, alkali metal or alkaline-earth metal perhalogenate.
21. Composition according to claim 11 , wherein the at least one perhalogenate is at least one alkali metal or alkaline-earth metal perhalogenate.
22. Composition according to claim 11 , comprising:
10% to 30% by weight of diethylhydroxylamine;
10% to 30% by weight of sodium perchlorate;
optionally, up to 20% by weight of one or more stabilizers and/or co-stabilizers; and
the complement to 100% by weight of water.