Flexible polyurethane foams having improved air permeability

Abstract

The present invention relates to polyol mixtures comprising (b1) at least one polyether polyol having a hydroxyl value of 10 to 60 mg KOH/g and having a high proportion of ethylene oxide, (b2) at least one polyether polyol having a hydroxyl value of 10 to 100 mg KOH/g, a low proportion of ethylene oxide, and not less than 40% primary OH groups, and (b3) at least one polyether polyol having a hydroxyl value of 10 to 100 mg KOH/g, a low proportion of ethylene oxide, and not more than 30% primary OH groups. The invention further relates to a process for producing flexible polyurethane foams using the mixtures according to the invention, to the thereby obtainable flexible polyurethane foams, and to the use of the thereby obtainable flexible polyurethane foams as a mattress or cushion, as a cushioning element for furniture or as a seat element.

Claims

1. An elastic foam made from at least one polyisocyanate based on diphenylmethane diisocyanate, and a mixture b comprising the following components: b1) at least one polyether polyol having a hydroxyl value of 10 to 60 mg KOH/g, an OH functionality of more than 2, and oxyalkylene units comprising oxyethylene units in a proportion of 50 to 100% by weight based on the content of oxyalkylene units, b2) at least one polyether polyol having a hydroxyl value of 10 to 100 mg KOH/g, an OH functionality of more than 2, oxyalkylene units comprising oxyethylene units in a proportion of 2 to 30% by weight based on the content of oxyalkylene units, and a proportion of primary OH groups of 40 to 100% based on the total number of OH groups in component b2) b3) at least one polyether polyol having a hydroxyl value of 10 to 100 mg KOH/g, an OH functionality of more than 2, oxyalkylene units comprising oxyethylene units in a proportion of 0 to 30% by weight based on the content of oxyalkylene units, and a proportion of primary OH groups of greater than 0 to 30% based on the total number of OH groups in component b3) wherein b1) is present in an amount of 75 to 94% by weight, b2) is present in an amount of 3 to 20% by weight, and b3) is present in an amount of 3 to 20% by weight, in each case based on the total amount by weight of components b1) to b3), optionally b4) at least one further polyether polyol that differs from components b1) to b3), and optionally b5) a graft polyol based on one or more of components b1) to b3); wherein the amount of b4) is from 0 to 10 parts by weight and the amount of b5) is from 0 to 30 parts by weight based on 100 parts by weight of components b1) to b3); where the elastic foam has a rebound resilience measured according to DIN EN ISO 8307 of not less than 30%, and wherein the elastic foam exhibits an air permeability according to DIN EN ISO 7231 of at least 3.0 dm.sup.3/s.

2. The elastic foam according to claim 1, wherein the proportion of primary OH groups in component b2) based on the total number of OH groups in component b2) is from 50 to 100%.

3. The elastic foam according to claim 1, wherein the proportion of primary OH groups in component b3) based on the total number of OH groups in component b3) is from greater than 0 to 25%.

4. The elastic foam according to claim 1, wherein component b2) has an OH functionality of at least 2.4.

5. The elastic foam according to claim 1, wherein component b3) has an OH functionality of 2.4 to 3.

6. The elastic foam according to claim 1, wherein component b1) has an OH functionality of at least 2.4.

7. The elastic foam according to claim 1, wherein component b1) has a proportion of primary OH groups of 40 to 100% based on the total number of OH groups in component b1).

8. The elastic foam according to claim 1 comprising from to 92% by weight of component b1), from 4 to 16% by weight of component b2), and from 4 to 15% by weight of component b3).

9. The elastic foam according to claim 1, wherein component b) comprises from 0.5 to 8 parts by weight of filler present as a constituent of a graft polyol based on one or more of components b1) to b3), based on 100 parts by weight of components b1) to b3).

10. A process for producing flexible elastic polyurethane foams in which the following components are mixed to form a reaction mixture and converted into the flexible polyurethane foam: a) at least one polyisocyanate, wherein at least one of the polyisocyanates present is based on diphenylmethane diisocyanate, b) a mixture b comprising the following components: b1) at least one polyether polyol having a hydroxyl value of 10 to 60 mg KOH/g, an OH functionality of more than 2, and oxyalkylene units comprising oxyethylene units in a proportion of 50 to 100% by weight based on the content of oxyalkylene units, b2) at least one polyether polyol having a hydroxyl value of 10 to 100 mg KOH/g, an OH functionality of more than 2, oxyalkylene units comprising oxyethylene units in a proportion of 2 to 30% by weight based on the content of oxyalkylene units, and a proportion of primary OH groups of 40 to 100% based on the total number of OH groups in component b2) b3) at least one polyether polyol having a hydroxyl value of 10 to 100 mg KOH/g, an OH functionality of more than 2, oxyalkylene units comprising oxyethylene units in a proportion of 0 to 30% by weight based on the content of oxyalkylene units, and a proportion of primary OH groups of greater than 0 to 30% based on the total number of OH groups m component b3) wherein b1) is present in an amount of 75 to 94% by weight, b2) is present in an amount of 3 to 20% by weight, and b3) is present in an amount of 3 to 20% by weight, in each case based on the total amount by weight of components b1) to b3), optionally b4) at least one further polyether polyol that differs from components b1) to b3), and optionally b5) a graft polyol based on one or more of components b1) to b3); wherein the amount of b4) is from 0 to 10 parts by weight and the amount of b5) is from 0 to 30 parts by weight based on 100 parts by weight of components b1) to b3), c) optionally chain extenders and/or crosslinkers, d) at least one catalyst, and e) at least one blowing agent comprising water, and f) optionally one or more additives; where the elastic foam has a rebound resilience measured according to DIN EN ISO 8307 of not less than 30%, and wherein the elastic foam exhibits an air permeability according to DIN EN ISO 7231 of at least 3.0 dm.sup.3/s.

11. The process according to claim 10, wherein component a) comprises from 60 to 100% by weight of 4,4-diphenylmethane diisocyanate based on the total weight of component a).

12. The process according to claim 10, wherein component a) comprises from 65 to 90% by weight of 4,4-diphenylmethane diisocyanate, from 0 to 20% by weight of 2,4-diphenylmethane diisocyanate, and from 10 to 30% by weight of multiring diphenylmethane diisocyanate, in each case based on the total weight of component a).

13. The process according to claim 10, wherein component a) comprises from 68 to 90% by weight of 4,4-diphenylmethane diisocyanate, from 0 to 20% by weight of 2,4-diphenylmethane diisocyanate, and from 10 to 30% by weight of multiring diphenylmethane diisocyanate, in each case based on the total weight of component a).

14. The process according to claim 10, wherein water is used as the sole blowing agent e).

15. The process according to claim 10, wherein the foam density according to DIN EN ISO 3386 of the flexible polyurethane foams is from 25 to 60 kg/m.sup.3.

16. The process according to claim 10, wherein the compression hardness at 40% according to DIN EN ISO 3386 of the flexible polyurethane foams is from 2 to 10 kPa.

17. The process according to claim 10, wherein the rebound resilience of the flexible polyurethane foams according to DIN EN ISO 8307 is at least 45%.

18. A flexible polyurethane foam obtained by the process according to claim 10.

19. A mattress, cushion, or seat element comprising the flexible polyurethane foam according to claim 18.

Description

EXAMPLES

(1) The constituents listed in Tables 2, 3, 5, and 7 were foamed to a flexible polyurethane foam using water as blowing agent.

(2) For this purpose, a poyol component was produced by mixing the specified polyether polyols, catalysts, and additives. The polyol component was mixed with the specified polyisocyanates at an index of 100 and introduced into an open mold.

(3) The properties of the resulting flexible polyurethane foams are given in Tables 4, 6, and 8 below.

(4) Starting materials used: Polyol A: OH value 42 mg KOH/g, polyether polyol based on propylene oxide and ethylene oxide (72% by weight) having 77% primary OH groups, starter glycerol. The mean functionality is 2.7. Polyol B: OH value 35 mg KOH/g, polyether polyol based on propylene oxide and ethylene oxide (13% by weight) having 72% primary OH groups, starter glycerol. The mean functionality is 2.7. Polyol C: OH value 48 mg KOH/g, polyether polyol based on propylene oxide and ethylene oxide (10% by weight) having fewer than 5% primary OH groups, starter glycerol, ethylene glycol. The mean functionality is 2.5. Polyol D: OH value 20 mg KOH/g, graft polyol having a 45% content of solids (styrene-acrylonitrile) in polyol B as carrier polyol. The mean functionality is 2.7. Polyol E: OH value 29 mg KOH/g, polyether polyol based on propylene oxide and ethylene oxide (16% by weight) having 79% primary OH groups, starter glycerol. The mean functionality is 2.7. DEOADiethanolamine 80% in water DABCO33 LVGel catalyst in dipropylene glycol (Air Products) Niax A1Blowing catalyst (Momentive) DABCO NE 300Blowing catalyst (Air Products) Tegostab B 4900Silicone stabilizer (Evonik) Tegostab B8783 LF2Silicone stabilizer (Evonik) Isocyanate A: NCO content 31.5% by weight, mixture of two-ring and multiring MDI having a functionality of 2.7 Isocyanate B: NCO content 33.5% by weight, 4,4-MDI (99%) Isocyanate C: NCO content 33.5% by weight, 4,4-MDI (50%) and 2,4-MDI (50%) isomer mixture

(5) TABLE-US-00001 TABLE 1 Standards used for foam tests Property Unit Standard Foam density kg/m.sup.3 DIN EN ISO 3386 Compression hardness kPa DIN EN ISO 3386 40% Hysteresis % DIN EN ISO 3386 Tensile strength kPa DIN EN ISO 1798 Elongation at break % DIN EN ISO 1798 Tear resistance N/mm DIN EN ISO 34-1, B(b) Air permeability.sup.2 dm.sup.3/s DIN EN ISO 7231 Rebound resilience % DIN EN ISO 8307 FT.sup.1 - Loss of hardness % DIN EN ISO 3385 .sup.1FTFatigue test .sup.2Measured after fulling the foam to achieve complete cell opening.

(6) TABLE-US-00002 TABLE 2 Composition of component A used (isocyanates A, B, and C and polyether polyol A) in parts by weight. This was used to calculate the composition of component a) in % by weight. The missing amount to 100% by weight is in each case 2,2-MDI. Multi- Poly- 4,4 2,4 ring ether MDI MDI MDI Iso Iso Iso polyol [% by [% by [% by A B C A weight] weight] weight] Isocyanate 1 37.5 20.4 42.1 54.8 22.4 21.8 Isocyanate 2 30.0 36.3 33.7 63.5 18.2 17.5 Isocyanate 3 35.2 35.2 17.1 12.5 64.3 11.8 23.4 Isocyanate 4 2.63 44.3 29.5 68.0 16.1 15.3 isocyanate 5 40.0 50.0 10.0 71.4 2.7 25.9 Isocyanate 6 31.3 53.5 15.2 71.9 9.5 18.2 Isocyanate 7 28.2 48.2 13.7 10.0 71.9 9.5 18.2 Isocyanate 8 24.6 54.6 12.0 8.8 75.6 8.4 15.7 Isocyanate 9 29.0 61.0 10.0 78.9 2.3 18.8

(7) TABLE-US-00003 TABLE 3 Amounts used of the freely-foamed flexible polyurethane foams (total weight of the components used: isocyanate, polyols, and additives approx. 2.5 kg). All data in parts by weight. Example V1 V2 V3 V4 V5 V6 1 2 3 4 Polyol A 65.0 70.0 80.0 80.0 80.0 80.0 75.0 80.0 80.0 80 Polyol B 15.0 10.0 7.0 5.0 13.0 Polyol C 7.0 7.0 20.0 2.0 7.0 12.0 7.0 7.0 Polyol D 13.0 13.0 20.0 13.0 18.0 13.0 8.0 13.0 Isoc. 7 49.7 49.8 50.6 49.4 49.6 49.5 49.8 50.3 49.9 50.3 33 LV 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.1 NE 300 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.3 B 4900 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Water 2.45 2.45 2.45 2.45 2.45 2.45 2.45 2.45 2.45 2.45 Index 100 100 100 100 100 100 100 100 100 100 % by weight of polyol A 69.0 74.3 80.0 87.9 85.0 87.1 79.7 83.0 85.0 80.0 (comp. b1) % by weight of polyol B 23.5 18.2 12.1 15.0 10.8 12.9 4.6 7.6 13.0 (comp. b2) % by weight of polyol C 7.5 7.5 20.0 2.1 7.4 12.4 7.4 7.0 (comp. b3) Further parts by weight of 5.9 5.9 9.0 5.9 8.1 5.9 3.6 5.9 filler SAN (comp. b5)

(8) The amounts by weight indicated by A, B, and C are % by weight and come to 100% by weight. The amount indicated by SAN is further parts by weight in addition to 100 parts by weight of components A, B, and C.

(9) A foam comprising 50 parts polyol A, 30 parts poyol B, 7 parts poyol C, and 13 parts polyol D collapsed and could not be characterized.

(10) TABLE-US-00004 TABLE 4 Mechanical properties of the resulting flexible foams. Example V1 V2 V3 V4 V5 V6 1 2 3 4 Foam density 42.4 42.3 42.3 41.4 41.8 41.6 41.7 41.4 41.6 43.0 (kg/m.sup.3) Compression 2.6 2.7 2.5 4.4 3.6 3.5 2.7 2.4 3.0 3.5 hardness 40% (kPa) Hysteresis (%) 26.5 26.1 24.2 24.8 22.5 23.7 24.1 23.7 23.5 24.7 Tensile strength 98 85 35 34 38 37 68 61 72 37 (kPa) Elongation at 176 168 102 55 75 71 145 136 152 93 break (%) fear resistance 0.75 6.73 6.44 0.30 0.33 0.33 0.68 0.62 0.58 0.40 (N/mm) Air permeability.sup.2 2.0 2.9 6.4 2.6 2.5 2.6 3.8 6.0 4.8 3.9 (dm.sup.3/s) Rebound 45 46 47 47 50 48 47 48 49 48 resilience (%) FT.sup.1 - Loss of 16.7 16.3 21.1 22.2 17.3 16.7 14.2 15.2 14.9 15.6 hardness (%) .sup.1FTFatigue test .sup.2Measured after fulling the foam to achieve complete cell opening.

(11) TABLE-US-00005 TABLE 5 Constituents of the freely-foamed flexible polyurethane foams (total weight of the components used: isocyanate, polyether polyols, and additives approx. 2.5 kg). All data in parts by weight. Example 5 6 7 8 9 10 3 11 12 Polyol A 80.0 80.0 80.0 80.0 80.0 80.0 80.0 80.0 80.0 Polyol C 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 Polyol D 13.0 13.0 13.0 13.0 13.0 13.0 13.0 13.0 13.0 Iso # Iso 1 Iso 2 Iso 3 Iso 4 Iso 5 Iso 6 Iso 7 Iso 8 Iso 9 Parts 44.3 44.1 51.9 44.0 49.4 44.1 49.9 49.0 49.0 33 LV 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 NE 300 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 B 4900 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Water 2.45 2.45 2.45 2.45 2.45 2.45 2.45 2.45 2.45 Index 100 100 100 100 100 100 100 100 100 % by weight of polyol A 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 (comp. b1) % by weight of polyol B 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.6 (comp. b2) % by weight of polyol C 7.4 7.4 7.4 7.4 7.4 7.4 7.4 7.4 7.4 (comp. b3) Further parts by weight 5.9 5.9 5.9 5.9 5.9 5.9 5.9 5.9 5.9 of filler SAN (comp. b5)

(12) The amounts by weight indicated by A, B, and C are % by weight and come to 100% by weight. The amount indicated by SAN is further parts by weight in addition to 100 parts by weight of components A, B, and C.

(13) TABLE-US-00006 TABLE 6 Mechanical properties of the resulting flexible foams. Example 5 6 7 8 9 10 3 11 12 Foam density (kg/m.sup.3) 39.8 38.8 42.2 39.6 42.1 40.4 41.6 41.8 42.1 Compression hard- 1.1 1.9 1.4 2.9 2.5 3.1 3.0 3.2 3.2 ness 40% (kPa) Hysteresis (%) 19.3 23.1 16.7 26.2 21.7 25.1 23.5 22.6 21.1 Tensile strength (kPa) 48 55 54 56 67 55 72 54 59 Elongation at break 142 152 134 127 139 115 152 107 124 (%) Tear resistance 0.54 0.61 0.45 0.60 0.52 0.51 0.58 0.45 0.44 (N/mm) Air permeability.sup.2 4.7 4.8 5.0 4.4 4.5 4.5 4.8 4.6 5.0 (dm.sup.3/s) Rebound resilience 33 42 35 48 45 46 49 52 54 (%) FT.sup.1 - Loss of hard- 12.5 12.0 12.3 16.4 12.1 15.4 14.9 15.7 15.0 ness (%) .sup.1FTFatigue test .sup.2Measured after fulling the foam to achieve complete cell opening.

(14) TABLE-US-00007 TABLE 7 Constituents of the freely-foamed flexible polyurethane foams (total weight of the components used: isocyanate, polyols, and additives approx. 2.5 kg). All data in parts by weight. Example V7 V8* V9 V10* 3 Polyol A 1.0 1.0 80.0 Polyol B 17.6 17.6 Polyol C 7.0 Polyol D 10.2 10.2 13.0 Polyol E 72.5 72.5 99.0 99.0 DEOA 1.2 1.2 1.2 1.2 Iso # Iso 1 Iso 7 Iso1 Iso 7 Iso 7 Parts 49.7 56.0 51.1 56.8 49.9 33 LV 0.25 0.25 0.25 0.25 0.1 NE 300 0.15 0.15 0.3 Niax A1 0.05 0.05 B8783 LF2 0.35 0.35 0.35 0.35 B 4900 1.00 Water 2.75 2.75 3.25 3.25 2.45 Index 100 100 90 90 100 *Foams V8 and V10 collapsed and could not be characterized.

(15) TABLE-US-00008 TABLE 8 Mechanical properties of the resulting flexible foams Example V7 V9 3 Foam density (kg/m.sup.3) 45.3 39.0 41.6 Compression hardness 4.5 2.8 3.0 40% (kPa) Hysteresis (%) 28.3 26.6 23.5 Tensile strength (kPa) 74 85 72 Elongation at break (%) 92 124 152 Tear resistance (N/mm) 0.34 0.45 0.58 Air permeability.sup.2 (dm.sup.3/s) 0.8 1.0 4.8 Rebound resilience (%) 56 60 49 FT.sup.1 - Loss of hardness (%) 28.0 29.9 14.9 .sup.1FTFatigue test .sup.2Measured after fulling the foam to achieve complete cell opening.