POLYURETHANE INSULATING FOAMS AND PRODUCTION THEREOF

Abstract

A process is described for producing PU foams, especially rigid PU foams, based on foamable reaction mixtures containing polyisocyanates, compounds having reactive hydrogen atoms, blowing agents, foam stabilizers, and possibly further additives, wherein polymer particles are additionally used, the average particle size of the polymer particles being <100 μm, preferably <70 μm, especially 5 to 50 μm.

Claims

1-12. (canceled)

13. A composition for the production of rigid polyurethane foam, comprising at least one isocyanate component, a polyol component, and optionally, one or more components selected from the group consisting of: a catalyst which catalyses the formation of a urethane or isocyanurate bond; a blowing agent; and a foam stabilizer; and wherein the composition additionally comprises polymer particles with an average particle size of <100 μm.

14. The composition of claim 13, wherein the polymer particles have an average particle size of <70 μm.

15. The composition of claim 13, wherein the polymer particles have an average particle size of 5 to 50 μm.

16. The composition of claim 13, wherein the polymer particles are formed from a polymer selected from the group consisting of: polyethylene, polypropylene, polyamide, polyester, polystyrene, polyacrylate, polymethyl methacrylate, polycarbonate, styrene-acrylonitrile copolymers, polyether, polylactic acid, polyurethane, polysulfone, polyethersulfone, polyetherimide, polyimide and mixtures thereof.

17. The composition of claim 13, wherein the polymer particles are formed from a polymer selected from the group consisting of: a polyamide selected from the group consisting of: PA6, PA6.6, PA10, PA11 and PA12; a polyester selected from the group consisting of: polyethylene terephthalate, polybutylene terephthalat and poly-ε-caprolactone; and mixtures thereof.

18. The composition of claim 13, wherein the polymer particles are formed from polystyrene and/or polymethyl methacrylate.

19. The composition of claim 13, wherein the polymer particles are used in a total amount of 0.01 to 20 parts per 100 parts of polyol.

20. The composition of claim 13, wherein the polymer particles are used in a total amount of 0.1 to 5 parts per 100 parts of polyol.

21. The composition of claim 13, wherein the polymer particles are treated with a hydrocarbon having 3, 4 or 5 carbon atoms; a perfluorinated compound; a hydrochloro-fluorocarbon; a hydrohaloolefin; an oxygen-containing compound; or a chlorinated hydrocarbon.

22. The composition of claim 13, wherein the polymer particles are treated with a cyclo-, iso- or n-pentane hydrofluorocarbon; a perfluorinated compound selected from the group consisting of: perfluoropentane, perfluorohexane, and mixtures thereof; a hydrochloro-fluorocarbon selected form the group consisting of: HCFC 141b, hydrofluoroolefins (HFO) and mixtures thereof; a hydrohaloolefin selected from the group consisting of: 1234ze, 1234yf, 1224yd, 1233zd(E) and 1336mzz; an oxygen-containing compound selected from the group consisting of: ethyl formate, acetone and dimethoxymethane; or a chlorinated hydrocarbon selected from the group consisting of: dichloromethane and 1,2-dichloroethane.

23. The composition of claim 16, wherein the polymer particles have an average particle size of 5 to 50 μm.

24. The composition of claim 23, wherein the polymer particles are used in a total amount of 0.01 to 20 parts per 100 parts of polyol.

25. The composition of claim 24, wherein the polymer particles are treated with a hydrocarbon having 3, 4 or 5 carbon atoms; a perfluorinated compound; a hydrochloro-fluorocarbon; a hydrohaloolefin; an oxygen-containing compound; or a chlorinated hydrocarbon.

26. The composition of claim 25, wherein the polymer particles are formed from polystyrene and/or polymethyl methacrylate.

27. The composition of claim 26, wherein the polymer particles are used in a total amount of 0.1 to 5 parts per 100 parts of polyols.

28. A process for producing polyurethane foams, comprising reacting a foamable reaction mixture containing polyisocyanates, compounds having reactive hydrogen atoms, blowing agents, foam stabilizers, and, optionally, further additives, and wherein the reaction mixture additionally comprises polymer particles with an average particle size of <100 μm.

29. The process of claim 28, wherein the polymer particles have an average particle size of 5 to 50 μm.

30. The process of claim 29, wherein the polymer particles are formed from a polymer selected from the group consisting of: polyethylene, polypropylene, polyamide, polyester, polystyrene, polyacrylate, polymethyl methacrylate, polycarbonate, styrene-acrylonitrile copolymers, polyether, polylactic acid, polyurethane, polysulfone, polyethersulfone, polyetherimide, polyimide and mixtures thereof.

31. The process of claim 30, wherein the polymer particles are present in a total amount of 0.01 to 20 parts per 100 parts of polyols.

32. A dispersion comprising polymer particles having an average particle size of 5 to 50 μm, wherein the dispersion further comprises at least one polyol and/or solvent, optionally a blowing agent and/or dispersing additive, and wherein the polymer particles are treated with a fluorine-containing organic compound and/or a linear, branched or cyclic hydrocarbon.

Description

EXAMPLES

Example 1: Rigid PUR Foam

[0062] The following foam formulation was used for the performance comparison:

TABLE-US-00002 Component Proportion by weight Polyether polyol* 100 Catalyst** 2 Polyether siloxane*** 2 Water 1 Cyclopentane 14 Polymer particles according to the invention**** 1 MDI***** 154 *Daltolac ® R 471 from Huntsman, OH number 470 mg KOH/g **POLYCAT ® 8 from Evonik Industries AG ***TEGOSTAB ® B 84510 from Evonik Industries AG ****DEGACRYL ® M 527, polymethyl methacrylate powder, average particle size 33-41 μm according to ISO 13320-1, from Evonik Industries AG *****Polymeric MDI, 200 mPa*s, 31.5% NCO, functionality 2.7.

[0063] The comparative foamings were carried out by hand mixing. For this purpose, polyol, catalysts, water, foam stabilizer, particles and blowing agent were weighed into a beaker and mixed by means of a disc stirrer (diameter 6 cm) at 1000 rpm for 30 s. By reweighing, the amount of blowing agent that had evaporated in the mixing operation was determined and added again. The MDI was now added, the reaction mixture was stirred with the stirrer described at 2500 rpm for 7 s and immediately transferred into an aluminium mould thermostatted to 45° C. and having a size of 145 cm×14 cm×3.5 cm, the mould being inclined at an angle of 10° (along the 145 cm long side) and lined with polyethylene film. The foam formulation was in this case introduced at the lower side, so that the expanding foam fills the mould in the feed region and rises in the direction of the higher side. The amount of foam formulation used was calculated such that it was 10% above the amount necessary for minimum filling of the mould.

[0064] After 10 min, the foams were demoulded. One day after foaming, the foams were analysed. Surface and internal defects were assessed subjectively on a scale from 1 to 10, where 10 represents an (idealized) impeccable foam and 1 represents a very significantly defective foam. The thermal conductivity coefficient was measured on 2.5 cm thick discs using a Hesto A Control instrument at temperatures of 10° C. and 36° C. for the bottom side and the top side of the sample. For the determination of an ageing value for the thermal conductivity, the test specimens were stored at 70° C. over 7 days and then measured again. The open-cell content was measured using an AccuPyc II 1340 gas pycnometer from Micromeritics.

[0065] The results are compiled in the table which follows:

TABLE-US-00003 Reference According to Parameter (without particles) the invention Density kg/m.sup.3 50.2 50.2 Thermal conductivity 22.8 21.7 mW/m*K initial Thermal conductivity 24.4 23.4 mW/m*K aged Open-cell content % 6.6 6.1 Defects 5/5.5/4 5/5/4.5 (top/bottom/internal)

[0066] The results show that a significant improvement in the thermal conductivity can be achieved with the particles according to the invention. The values, both in the fresh and in the aged state, are very significantly below the reference value of the foam without addition of polymer particles. All other application-relevant foam properties are only insignificantly affected, if at all, by the particles according to the invention. Even in the case of the quite sensitive surface quality of the foam test specimens, no deterioration, or only a marginal deterioration, is found.

Example 2: Rigid PIR Foam

[0067] The following foam formulation was used for the performance comparison:

TABLE-US-00004 Component Proportion by weight Polyester polyol* 100 Amine catalyst** 0.6 Potassium trimerization catalyst*** 4 Polyether siloxane**** 2 Water 1 Cyclopentane 16 Flame retardant TCPP 15 Polymer particles according to the invention***** 1 MDI****** 199 *Stepanpol ® PS 2352 from Stepan, OH number 250 mg KOH/g **POLYCAT ® 5 from Evonik Industries AG ***KOSMOS ® 75 from Evonik Industries AG ****TEGOSTAB ® B 84510 from Evonik Industries AG *****DEGACRYL ® M 527, polymethyl methacrylate powder, average particle size 33-41 μm according to ISO 13320-1, from Evonik Industries AG ******Polymeric MDI, 200 mPa*s, 31.5% NCO, functionality 2.7.

[0068] The comparative foamings were carried out by hand mixing. For this purpose, polyol, catalysts, water, foam stabilizer, flame retardant, particles and blowing agent were weighed into a beaker and mixed by means of a disc stirrer (diameter 6 cm) at 1000 rpm for 30 s. By reweighing, the amount of blowing agent that had evaporated in the mixing operation was determined and added again. The MDI was now added, the reaction mixture was stirred with the stirrer described at 3000 rpm for 5 s and immediately transferred into an aluminium mould thermostatted to 60° C. and having a size of 25 cm×50 cm×7 cm, the mould being lined with polyethylene film.

[0069] After 10 min, the foams were demoulded. One day after foaming, the foams were analysed. Surface and internal defects were assessed subjectively on a scale from 1 to 10, where 10 represents an (idealized) impeccable foam and 1 represents a very significantly defective foam. The thermal conductivity coefficient was measured on 2.5 cm thick discs using a Hesto A Control instrument at temperatures of 10° C. and 36° C. for the bottom side and the top side of the sample. For the determination of an ageing value for the thermal conductivity, the test specimens were stored at 70° C. over 7 days and then measured again. The open-cell content was measured using an AccuPyc II 1340 gas pycnometer from Micromeritics.

[0070] The results are compiled in the table which follows:

TABLE-US-00005 Reference According to Parameter (without particles) the invention Density kg/m.sup.3 37.1 37.2 Thermal conductivity 21.0 20.2 mW/m*K initial Thermal conductivity 24.5 23.3 mW/m*K aged Open-cell content % 12.2 13.1

[0071] The results again show that a significant improvement in the thermal conductivity can be achieved with the polymer particles according to the invention, with the values both in the fresh and in the aged state here too being significantly below the reference value of the foam without addition of polymer particles.

[0072] It should be particularly emphasized here that even a very small addition of particles according to the invention leads to measurable improvements.

[0073] All other application-relevant foam properties are only insignificantly affected, if at all, by the particles according to the invention. Even in the case of the quite sensitive surface quality of the foam test specimens, no deterioration, or only a marginal deterioration, is found.