Polymerization process for liquid copolymers of ethylene and hydroxyalkyl(meth)acrylate
The present invention relates to a continuous high-pressure polymerization process for the preparation of a liquid ethylene copolymer which comprises in polymerized for methylene; and a reactive acrylate which is selected from hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate, where a monomer feed comprising the ethylene and the reactive acrylate is polymerized in the presence of at least 2 wt % of a chain transfer agent. The present invention also relates to the liquid ethylene copolymer, to a coating material comprising the liquid ethylene copolymer and to a use of the liquid ethylene copolymer to produce a coating material.
1. A continuous high-pressure polymerization process for the preparation of a liquid ethylene copolymer which comprises in polymerized form
ethylene;
a reactive acrylate which is selected from hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate, and
an alkyl (meth)acrylate which is selected from C 1 -C 22 alkyl (meth)acrylate;
wherein a monomer feed comprising the ethylene and the reactive acrylate is polymerized in the presence of at least 2 wt % of a chain transfer agent.
2. The polymerization process according to claim 1 , wherein the chain transfer agents are saturated or unsaturated hydrocarbons, aliphatic ketones, aliphatic aldehydes, or hydrogen, or mixtures thereof.
3. The polymerization process according to claim 1 , wherein the chain transfer agents are propionaldehyde, methyl ethyl ketone, or hydrogen, or mixtures thereof.
4. The polymerization process according to claim 1 , wherein the monomer feed is polymerized in the presence at least 8 wt % of the chain transfer agent.
5. The polymerization process according to claim 1 , wherein the chain transfer agent is a mixture of propionaldehyde and methyl ethyl ketone in a weight ratio of 4:1 to 1:4.
6. The polymerization process according to claim 1 , wherein the polymerization process is carried out at a pressure in the range from 1000 to 4000 bar.
7. The polymerization process according to claim 1 , wherein the polymerization process is carried out at a pressure in the range from 1200 to 2500 bar.
8. The polymerization process according to claim 1 , wherein the polymerization process is carried out at a pressure in the range from 1600 to 2000 bar.
9. The polymerization process according to claim 1 , wherein the ethylene copolymer comprises in polymerized form 20 to 60 wt % of the ethylene.
10. The polymerization process according to claim 1 , wherein the ethylene copolymer comprises in polymerized form more than 2 wt % of the reactive acrylate.
11. The polymerization process according to claim 1 , wherein the ethylene copolymer comprises in polymerized form at least 10 wt % of the alkyl (meth)acrylate.
12. The polymerization process according to claim 1 , wherein the alkyl (meth)acrylate is selected from C 1 -C 12 alkyl (meth)acrylate.
13. The polymerization process according to claim 1 , wherein the ethylene copolymer comprises from 15 to 70 wt % of the alkyl (meth)acrylate.
14. The polymerization process according to claim 1 , wherein the ethylene copolymer is free of further monomers beside the ethylene, the reactive acrylate, and the alkyl (meth)acrylate.
15. A liquid ethylene copolymer produced by the process as defined in claim 1 .
16. A coating material comprising the liquid ethylene copolymer as defined in claim 15 .
17. A continuous high-pressure polymerization process for the preparation of a liquid ethylene copolymer which comprises in polymerized form
ethylene; and
a reactive acrylate which is selected from hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate,
wherein a monomer feed comprising the ethylene and the reactive acrylate is polymerized in the presence of at least 2 wt % of a chain transfer agent and wherein the chain transfer agent is a mixture of propionaldehyde and methyl ethyl ketone in a weight ratio of 4:1 to 1:4.