High pressure radial polymerisation process for a copolymer of ethylene silane groups containing comonomer
A copolymer of ethylene with silane groups containing comonomer that is produced in a high pressure radical polymerisation process comprising the steps of: (a) compressing ethylene together with the silane groups containing comonomer under pressure in a compressor, wherein a compressor lubricant is used for lubrication, (b) polymerising ethylene together with the silane groups containing comonomer in a polymerisation zone, (c) separating the obtained ethylene from the unreacted products and recovering the separated ethylene copolymer in a recovery zone, wherein in step a) the compressor lubricant comprises a mineral oil and ethylene copolymer has a silane groups containing comonomer content of 0.5 to 3 wt % and an MFR2 of 0.3 to 10 g/10 min. The copolymer of ethylene with silane groups containing comonomer can be used.
1. A high pressure radical process for producing a copolymer of ethylene with a silane groups containing comonomer, the process comprising:
(a) compressing the ethylene together with the silane groups containing comonomer under pressure in a compressor, wherein a compressor lubricant is used for lubrication,
(b) polymerising the ethylene together with the silane groups containing comonomer in a polymerisation zone to form the ethylene copolymer,
(c) separating the ethylene copolymer from unreacted products and recovering the separated ethylene copolymer in a recovery zone,
wherein in step (a) the compressor lubricant comprises a mineral oil;
wherein the ethylene copolymer has a silane groups containing comonomer content of 0.5 to 3 wt % and an MFR 2 of 0.3 to 10 g/10 min;
wherein the copolymer has a hot set elongation percentage y satisfying:
y<−81.205x+193.16, wherein x represents wt % of the silane groups containing comonomer, and
wherein the polymerisation step b) is operated at a pressure of up to 4000 bar and at a temperature of from 80 to 350° C.
2. The process of claim 1 , wherein the MFR 2 is from 0.5 to 2 g/10 min.
3. The process of claim 1 , wherein the MFR 2 is from 0.7 to 1.5 g/10 min.
4. The process of claim 1 , wherein the silane groups containing comonomer content is 0.5 wt % to 2 wt %.
5. The process of claim 1 , wherein the silane groups containing comonomer content is 0.5 wt % to 1 wt %.
6. The process of claim 1 , wherein the mineral oil is a petroleum product, or wherein the mineral oil comprises paraffinic hydrocarbons, or wherein the mineral oil does not comprise polyalkyleneglycol base components.
7. The process of claim 1 , wherein the copolymer of ethylene with silane groups containing comonomer is crosslinked with a condensation reaction catalyst that is acidic.
8. The process of claim 7 , wherein the condensation reaction catalyst is a sulphonic acid or a Bronsted acid.