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1. WO2019050402 - FLEXIBLE POLYOLEFIN THERMAL INSULATION FOAM AND USE THEREOF, AND A METHOD FOR PRODUCING A FLEXIBLE POLYOLEFIN THERMAL INSULATION FOAM

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[ EN ]

CLAIMS

1. A non-crosslinked polyolefin thermal insulation foam having a percentage of open cells of less than 10% based on the total cells in the foam, and which is obtainable by extruding a mixture comprising:

i) an ethylene/ a-olefin block copolymer, which comprises blocks of:

A) crystalline or semi-crystalline blocks characterized by comprising ethylene in an amount of higher than 95 weight %; and

B) elastomeric blocks characterized by comprising ethylene in an amount of 95 weight % or less and a comonomer content of 5 weight % or higher;

ii) one or more random polymers with a density of between 0, 880 g/cm3 and 960 g/cm3, selected from the group of a metallocene polyethylene and/or a polyethylene ; and

iii) a cell stabilizer;

in a process comprising the steps of

a) melting said mixture in the melting zone(s) of the extruder adjusted to temperatures of 160 to 220°C, at a pressure increasing from 1 bar up to 400 bar,

b) injecting said physical blowing agent at an injection temperature of 140 to 220°C and an injection pressure of 30 to 300 bar,

c) cooling the molten mixture in one or more cool-ing zones adjusted to temperatures of 85 to 115°C, and

d) extruding the mixture through an extrusion nozzle adjusted to a temperature of 85 to 115°C and a pressure sufficiently high to keep any gas present in the mixture dissolved in the mixture.

2. The non-crosslinked polyolefin thermal insulation foam according to claim 1, wherein the thermal insulation foam has a percentage of open cells of 6 (+/-3) % or less based on the total cells in the foam.

3. The non-crosslinked polyolefin thermal insulation foam according to claim 1 or 2, wherein cooling the molten mixture takes place gradually.

4. The non-crosslinked polyolefin thermal insulation foam according to any of the previous claims, wherein said oi-olefin is a C3-C10 a-olefin.

5. The non-crosslinked polyolefin thermal insulation foam according to any of the previous, wherein said ethylene/ α-olefin block copolymer comprises alternating blocks of crystalline blocks of linear medium-density polyethylene and elastomeric blocks of ethylene/l-octene .

6. The non-crosslinked polyolefin thermal insulation foam according to any of the previous claims, wherein said ethylene/ a-olefin block copolymer has a density between 800 and 880 g/cm3.

7. The non-crosslinked polyolefin thermal insulation foam according to any of the previous claims, wherein said polymers have MFI-values of < 1.2 g/10 minutes at 2.16 kg @ 190°C as determined in accordance with ASTM D1238

8. The non-crosslinked polyolefin thermal insulation foam according to any of the previous claims, wherein said polyethylene under ii) is LDPE .

9. The non-crosslinked polyolefin thermal insula-tion foam according to any of the previous claims, wherein said metallocene polyethylene under ii) is an ethylene based octane metallocene.

10. The non-crosslinked polyolefin thermal insula-tion foam according to any of the previous claims, wherein said one or more random polymers comprise both a said metallocene polyethylene and a said polyethylene.

11. The non-crosslinked polyolefin thermal insulation foam according to any previous claims, wherein said mixture comprises one or more additives selected from the group consisting of a flame retardant, a cell nucleator, a colourant, an isolation improver, an UV stabilizer, a processing aid, a processing stabilizer, and an anti-oxidant .

12. The non-crosslinked polyolefin thermal insulation foam according to any of the previous claims, wherein the mixture comprises between 25 and 80 weight % of said one or more olefin based polymers under ii) .

13. The non-crosslinked polyolefin thermal insulation foam according to any of previous claims, wherein the mix-ture comprises between 20 and 75 weight % of said ethylene/ oi-olefin block copolymer under i) .

14. The non-crosslinked polyolefin thermal insulation foam according to any of previous claims, wherein the mixture comprises 20-60 weight % of said ethylene/ a-olefin block copolymer, 10-20 weight % LDPE, and 20-40 weight% ethylene based octane metallocene based on the weight of the composition.

15. The non-crosslinked polyolefin thermal insulation foam according to any of the claims 1 to 14, which is in the form of a cylinder.

16. The non-crosslinked polyolefin thermal insulation foam according to any of the claims 1 to 14, which is in the form of a sheet.

17. A method for making non-crosslinked polyolefin thermal insulation foam comprising extruding, using a physical blowing agent, a mixture as defined in any of the claims 1 to 14, in an extruder, said method comprising the steps of

a) melting said mixture in one or more melting zones of the extruder adjusted to temperatures of 160 to 220°C, at a pressure increasing from 1 bar up to 400 bar, b) injecting said physical blowing agent at an in-jection temperature of 140 to 220°C and an injection pressure of 30 to 300 bar,

c) cooling the molten mixture in one or more cooling zones adjusted to temperatures of 85 to 115°C, and

d) extruding the mixture through an extrusion noz-zle adjusted to a temperature of 85 to 115°C and at a pressure sufficiently high to keep any gas present in the mixture dissolved in the mixture.

18. The method according to claim 17, wherein said mixture is a water-free mixture.

19. Use of a non-crosslinked polyolefin thermal insulation foam according to any of the claims 1-16 for thermal isolation.