Polyurethane elastomer gel insulating composition and use thereof
View Patent ↗The invention relates to the use of a thermally insulating composition in the form of crosslinked polyurethane elastomer gel, obtained by reacting at least one polyol and at least one polyisocyanate in the presence of at least one inert organic filler, for the thermal insulation of pipeline systems present in a product-transfer conduit.
1. District heating conduit comprising at least one PVC pipeline system transporting hot water from a thermal power station to a housing, a tubular protective sheath made of a plastic, PVC or polyethylene through which the said PVC pipeline system passes, and a filling made of a thermally insulating material, wherein the thermally insulating material consists of an insulating composition in the form of a polyurethane elastomer gel composition prepared by reacting a crosslinkable composition comprising at least one polyol and at least one polyisocyanate in the presence of at least one liquid organic filler chemically inert to the polyisocyanates.
2. Process for thermal insulation of a conduit for transporting materials, the conduit having an outer surface and a protective sheath, the protective sheath having an inner surface, an interstitial space between the outer surface of the conduit and the inner surface of the protective sheath comprising a) intimately mixing of at least one polyol component and at least one insulating inert liquid organic filler component chemically inert to polyisocyanates b) adding to the mixture of step a) at least one polyisocyanate component with intimate mixing of all of the components, c) casting or injection moulding of the resultant mixture from step b) into the interstitial space and d) crosslinking and solidification in situ to obtain the thermally insulated conduit ready for use at its point of use.
3. Process according to claim 2 in which the steps c) moulding and d) crosslinking are implemented in a mould to obtain premoulded sections of thermal insulation for the conduit for transporting liquid materials, and comprising an additional step e) assembling these premoulded sections around the conduit.
4. Premolded sections of thermal insulation for a conduit which have been obtained by the process of claim 2 .
5. The method according to claim 2 , wherein the said organic filler is kerosene.
6. Conduit for sub-marine product transfer, comprising at least one pipeline system, optionally at least one pipeline system known as a service pipeline system, having a protective tubular sheath through which the said pipeline system passes and a filling made of a thermally insulating material, wherein the thermally insulating material consists of an insulating composition in the form of a gel obtained from a crosslinkable composition comprising at least one polyol and at least one polyisocyanate in the presence of at least one liquid organic filler chemically inert to the polyisocyanates.
7. The process according to claim 2 , wherein the inert liquid organic filler is more than 20% by weight of the entire composition.
8. The process according to claim 2 , wherein the inert liquid organic filler represents from 50 to 95% by weight of the entire composition.
9. The process according to claim 2 , wherein the inert liquid organic filler is selected from the group consisting of
C 18 –C 20 n- or iso-paraffins, chlorinated paraffins; heavy or light fuels; C 5 –C 12 naphthenic oils or resins; aromatic compounds and polyaromatic compounds, optionally containing one or more heteroatoms.
10. The process according to claim 2 , wherein the inert liquid organic filler is an n-paraffin or a mixture of n-paraffins.
11. The process according to claim 2 , wherein the inert liquid organic filler is a naphthenic resin.
12. The process according to claim 2 , wherein the inert liquid organic filler is an aviation fuel.
13. The process according to claim 2 , wherein the polyol is selected from the group consisting of polyester polyols, polyether polyols and polydiene polyols.
14. The process according to claim 2 , wherein the inert liquid organic filler is an optionally substituted aromatic or polyaromatic compound, optionally containing one or more heteroatoms.
15. The process according to claim 2 , wherein at least one polyol is polydiene polyol having a number-average molecular weight of no greater than 7 000, and a functionality of from 1 to 5.
16. The process according to claim 15 , wherein the polydiene polyol has a number-average molecular weight of about 1000 to 3000.
17. The process according to claim 15 , wherein the polydiene
polyol is a hydroxytelechelic oligomer of a conjugated diene.
18. The process according to claim 15 , wherein the polyol has a number-average molecular weight of about 1000 to 3000.
19. The process according to claim 15 , wherein the polydiene polyol is a hydroxytelechelic oligomer of butadiene.
20. The Process according to claim 2 , wherein the polyisocyanate is an aromatic, cycloaliphatic, or a prepolymer.
21. The process according to claim 2 , wherein the polyisocyanate is diphenylmethane 4,4′-diisocyanate (MDI) or a polymeric MDI.
22. The process according to claim 2 , wherein the polyisocyanate is a prepolymer prepared from a hydroxytelechelic oligomer of a conjugated diene, polyol and a polyisocyanate.
23. The process according to claim 2 , wherein the polyol comprises one or mare low-molecular weight polyols.
24. The process according to claim 23 , wherein the low-molecular weight polyol(s) has (have) a molecular weight of from 50 to 800.
25. The process according to claim 2 , wherein the NCO/OH molar ratio is between 0.5 and 2.
26. The process according to claim 2 , wherein the NCO/OH ratio is between 0.65 and 1.20.
27. The process according to claim 2 , comprising adding a crosslinking catalyst to the mixture.
28. The process according to claim 27 , wherein the said crosslinking catalyst is dibutyltin dilaurate.
29. The process according to claim 2 , the insulation having, after crosslinking, a thermal insulation factor below 0.25 W/m.k.