METHOD FOR LOWERING EMISSIONS OF A POLYURETHANE FOAM

Abstract

The present invention relates to a process for producing polyurethanes, preferably polyurethane foams, by reaction of compounds containing isocyanate-reactive hydrogen atoms with di- and/or polyisocyanates in the presence of one or more compounds selected from the group consisting of:

NC—CHR.sup.1—CON R.sup.12—X  (I),

NC—CHR.sup.2—CONR.sup.3-aryl  (II),

NC—CHR.sup.4—CO.sub.2H  (III),

[NC—CHR.sup.5—CO.sub.2].sub.mY.sup.m+  (IV), wherein X represents NR.sup.6R.sup.7, OR.sup.8, CONR.sup.9R.sup.10 or COOR.sup.11, R.sup.1 to R.sup.12 each independently of one another represent H, an optionally substituted C.sub.1-C.sub.8 alkyl group or an optionally substituted aryl group, Y represents a monovalent or divalent cation and m represents 1 or 2.

The present invention further relates to the polyurethanes obtainable from this process, and to the use of such polyurethanes, for example in the interior of automobiles.

Claims

1. A process for producing a polyurethane comprising reacting a compound containing isocyanate-reactive hydrogen atoms with a di- and/or polyisocyanate in the presence of one or more compounds selected from the group consisting of:
NC—CHR.sup.1—CONR.sup.12—X  (I), and
NC—CHR.sup.2—CONR.sup.3-aryl  (II), wherein X represents NR.sup.6R.sup.7, OR.sup.8, CONR.sup.9R.sup.10 or COOR.sup.11, R.sup.1, R.sup.2, R.sup.3, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, and R.sup.12 each independently of one another represents H, an unsubstituted C.sub.1-C.sub.8 alkyl group, a substituted C.sub.1-C.sub.8 alkyl group, an unsubstituted aryl group, or an optionally substituted aryl group, Y represents a monovalent or divalent cation, and m represents 1 or 2.

2. A process for producing a polyurethane foam comprising reacting with one another A1 a compound containing isocyanate-reactive hydrogen atoms having an OH number according to DIN 53240 of ≥15 to <260 mg KOH/g, A2 optionally a compound containing isocyanate-reactive hydrogen atoms having an OH number according to DIN 53240 of ≥260 to <4000 mg KOH/g, A3 water and/or a physical blowing agent, A4 optionally auxiliary and additive, A5 one or more compounds selected from the group consisting of:
NC—CHR.sup.1—CON R.sup.12—X  (I), and
NC—CHR.sup.2—CONR.sup.3-aryl  (II), wherein X represents NR.sup.6R.sup.7, OR.sup.8, CONR.sup.9R.sup.10 or COOR.sup.11, R.sup.1, R.sup.2, R.sup.3, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, and R.sup.12 each independently of one another represent H, an unsubstituted C.sub.1-C.sub.8 alkyl group, a substituted C.sub.1-C.sub.8 alkyl group, an unsubstituted aryl group, or a substituted aryl group, Y represents a monovalent or divalent cation, and m represents 1 or 2, and B a di- and/or polyisocyanate.

3. The process as claimed in claim 2, wherein compound (I) and/or (II) is present in an amount of 1 to 100 grams, based on 1 kilogram of the compounds containing isocyanate-reactive hydrogen atoms and the di- and/or polyisocyanates.

4. The process as claimed in claim 2, wherein: A1 comprises 75 to 99.0 parts by weight, based on the sum of the parts by weight of components A1 to A4, of compounds containing isocyanate-reactive hydrogen atoms having an OH number according to DIN 53240 of ≥15 to <260 mg KOH/g, A2 comprises 0 to 10 parts by weight, based on the sum of the parts by weight of components A1 to A4, of compounds containing isocyanate-reactive hydrogen atoms having an OH number according to DIN 53240 of ≥260 to <4000 mg KOH/g, A3 comprises 0.5 to 24.5 parts by weight, based on the sum of the parts by weight of components A1 to A4, of water and/or physical blowing agents, A4 comprises 0.5 to 10 parts by weight, based on the sum of the parts by weight of components A1 to A4, of auxiliary and additive substances A5 comprises 1 to 100 grams, per kilogram of the sum of components A1 and B of one or more compounds structure (I) and/or structure (II), wherein all reported parts by weight for the components A1 to A4 are normalized such that the sum of the parts by weight of the components A1+A2+A3+A4 in the composition total 100 parts by weight.

5. The process as claimed in claim 2, wherein A1 comprises 25 to 45 parts by weight, based on the sum of the parts by weight of components A1 to A4, of compounds containing isocyanate-reactive hydrogen atoms having an OH number according to DIN 53240 of ≥15 to <260 mg KOH/g, A2 comprises 20 to 74 parts by weight, based on the sum of the parts by weight of components A1 to A4, of compounds containing isocyanate-reactive hydrogen atoms having an OH number according to DIN 53240 of ≥260 to <4000 mg KOH/g, A3 comprises 0.5 to 25 parts by weight, based on the sum of the parts by weight of components A1 to A4, of water and/or physical blowing agents, A4 comprises 0.5 to 10 parts by weight, based on the sum of the parts by weight of components A1 to A4, of auxiliary and additive substances and A5 comprises 1 to 100 grams, per kilogram of the sum of components A1 and B, of one or more compounds of structure (I) and/or structure (II), wherein all reported parts by weight for the components A1 to A4 are normalized such that the sum of the parts by weight of the components A1+A2+A3+A4 in the composition adds up to 100.

6. (canceled)

7. The process as claimed in claim 2, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, and R.sup.12 each independently of one another represent H or a C.sub.1-C.sub.6 alkyl group.

8. The process as claimed in claim 7, wherein R.sup.1 and R.sup.2 each represent H.

9. The process as claimed in claim 2, wherein component A1 comprises at least two hydroxyl-containing polyethers, optionally in admixture with at least two hydroxyl-containing polyesters.

10. The process as claimed in claim 2, wherein component A1 comprises at least 30% by weight of at least one polyoxyalkylene copolymer of a starter, propylene oxide and ethylene oxide and an end block made of ethylene oxide, wherein the total weight of the end blocks made of ethylene oxide is on average 3-20% by weight, based on the total weight of all polyoxyalkylene copolymers.

11. The process as claimed in claim 2, component B is a diphenylmethane diisocyanate mixture consisting of a) 45% to 90% by weight of 4,4′-diphenylmethane diisocyanate, b) 10% to 55% by weight of 2,2′-diphenylmethane diisocyanate and/or 2,4′-diphenylmethane diisocyanate, and c) 0% to 45% by weight of polyphenylpolymethylene polyisocyanate and/or 2,2′-, 2,4′-, 4,4′-diphenylmethane diisocyanate-based and/or pMDI-based carbodiimides, uretdiones or uretdioneimines.

12. The process as claimed in claim 2, wherein component B is a diphenylmethane diisocyanate mixture consisting of: a) 35% to 45% by weight of 4,4′-diphenylmethane diisocyanate, b) 1% to 5% by weight of 2,2′-diphenylmethane diisocyanate and/or 2,4′-diphenylmethane diisocyanate, and c) 50% to 64% by weight of polyphenylpolymethylene polyisocyanate and/or 2,2′-, 2,4′-, 4,4′-diphenylmethane diisocyanate-based and/or pMDI-based carbodiimides, uretdiones or uretdioneimines.

13. A polyurethane/polyurethane foam obtained by the process as claimed in claim 2.

14. The polyurethane/polyurethane foam as claimed in claim 13, wherein the polyurethane/polyurethane foam has a density of 4 to 600 kg/m.sup.3.

15. Furniture cushioning, textile inlay, a mattress, an automotive seat, a headrest, an armrest, a sponge, a headlining, a door trim, a seat cover or a constructional element comprising the polyurethane/polyurethane foam of claim 13.

Description

EXAMPLES

[0464] Test Methods:

[0465] Compressive strength, damping and apparent density of the foams were determined in the foam expansion direction according to DIN EN ISO 3386-1. The test specimens had a volume of 5*5*5 cm.sup.3. A pre-loading of 2 kPa was established. The advancing rate was 50 mm/min.

[0466] The hydroxyl number was determined according to DIN 53240.

[0467] The open-cell content was measured with an AccuPyc 1330 gas displacement pycnometer.

[0468] The glass transition reported is the maximum of tan δ according to DIN EN ISO 6721-2 B (torsion pendulum method).

[0469] Determination of Aldehyde Emissions:

[0470] VDA 275 is a standardized test method of the organization Verband der Automobilindustrie (VDA). The version current at the date of filing is employed here. [0471] a) measurement method 1 (bottle method according to VDA 275): [0472] Charged into a glass bottle of 1 liter in volume are 50 milliliters of water. A foam sheet having dimensions of 40*10*2 cm.sup.3 is fixed freely suspended from the lid so that the foam is not in contact with the aqueous solution at the bottom of the bottle. The bottle is closed and stored in a recirculating air drying cabinet at 60° C. for 3 hours. The bottle is allowed to cool to room temperature and the foam is withdrawn. An aliquot of the aqueous solution is reacted with a solution of 0.3 mmol/liter of dinitrophenylhydrazine (DNPH) in 3 mM phosphoric acid-acidified acetonitrile. The composition of the aqueous solution is analyzed by LC-MS/MS for the hydrazones of the aldehydes recited below. For each foam quality three bottles are analyzed. For each test run a further three bottles without foam are coanalyzed. The average reference value is subtracted from the measured values. The emission of the respective aldehydes per kilogram of foam are extrapolated on this basis. This is reported in mg of aldehyde per kg of foam. [0473] b) measurement method 2 (modified bottle method): [0474] Charged into a glass bottle of one liter in volume are 25 milliliters of water and 25 millilitres of a solution of 0.3 mmol/liter of dinitrophenylhydrazine (DNPH) in 3 mM phosphoric acid-acidified acetonitrile. The content of DNPH is 7.5 μmol per bottle. A foam sheet having dimensions of 40*10*4 cm.sup.3 is fixed freely suspended from the lid so that the foam is not in contact with the aqueous solution at the bottom of the bottle. The bottle is closed and stored in a recirculating air drying cabinet at 65° C. for 3 hours. The bottle is allowed to cool to room temperature, the foam is withdrawn and the composition of the aqueous solution is analyzed by LC/MS-MS for the hydazones of the aldehydes recited below. For each foam quality three bottles are analyzed. For each test run a further three bottles without foam are coanalyzed. The average reference value is subtracted from the measured values. The emission of the respective aldehydes per kilogram of foam are extrapolated on this basis. This is reported in mg of aldehyde per kg of foam.

[0475] Description of Tests

[0476] The production of the polyurethane foams is carried out by mixing a polyol formulation A and an isocyanate component B.

[0477] The reported OH numbers are obtained according to DIN 53240 in the version current at the date of filing.

[0478] Test Series 1: Molded Flexible Foam, for Example for Sound Absorption

[0479] Description of Raw Materials [0480] A1-1: Polyether mixture of a glycerol-started polyalkylene oxide having a molar weight of 4.8 kg/mol, an OH number of 35 mg KOH/g and a content of ethylene oxide of <50% by weight and a propylene glycol-started polyalkylene oxide having a molar weight of 4 kg/mol and an OH number of 28 mg KOH/g in a weight ratio of 55:45. [0481] A2-1: Triethanolamine [0482] A3-1: Water [0483] A4-1: Isopur N black colour paste, commercially available from [0484] A4-2: Tegostab B8734 LF2 foam stabilizer, commercially available from Evonik Nutrition & Care, Essen [0485] A4-3: Glycerol-started polyalkylene oxide having an OH number of 37 mg KOH/g and a content of ethylene oxide of ≥50% by weight used as a cell-opener [0486] A4-4: Catalyst mixture of Jeffcat® DPA (commercially available from Huntsman) and Dabco® NE 300 (commercially available from Air Products) in a ratio of 6:1 (by weight) [0487] A5-1: Cyanoacetic acid 67% in DEG (diethylene glycol) [0488] B-1: Mixture of MDI isomers and homologs having a density of 1.24 kg/l, an isocyanate content of 323 g/kg and a viscosity of 0.05 Pa*s. The content of 4,4′-MDI is 55% by weight. The sum of 2,2′-MDI, 2,4′-MDI and 4,4′-MDI is 70% by weight.

TABLE-US-00001 Polyol formulation A Comparative Inventive 90V 90A Polyether mixture (A1-1) 91.7 87.8 Cell opener (A4-3) 1.5 1.5 Colour paste (A4-1) 0.2 0.2 Foam stabilizer (A4-2) 0.8 0.7 Crosslinker (A2-1) 0.6 0.6 Blowing agent (A3-1) 3.8 3.7 Catalyst (A4-4) 1.4 2.6 Cyanoacetic acid 67% in DEG (A5-1) — 2.9

[0489] Production of the Foams:

[0490] The ratio of isocyanate groups to isocyanate-reactive groups multiplied by 100 is described as the index. The following tests always compare foams produced using the same index. In two test series an index below 100 (excess of isocyanate-reactive groups) and an index above 100 were established.

TABLE-US-00002 Polyol component Isocyanate Isocyanate usage amount usage amount usage amount Index 90 grams grams grams Foam 90V 100 59 Foam 90A 100 61 Polyol component Isocyanate Isocyanate usage amount usage amount usage amount Index 105 grams grams grams Foam 105V 100 69 Foam 105A 100 71

[0491] To produce the foams the required amount of polyol is initially charged into a cardboard beaker having a sheet metal bottom (volume: about 850 ml) and loaded with air using a stirring means (Pendraulik) fitted with a standard stirring disk (d=64 mm) at 4200 rpm for 45 seconds.

[0492] The isocyanate/isocyanate mixture/prepolymer is weighed into a suitable beaker and emptied again (efflux time: 3 s). This beaker still having wet internal walls is tared and refilled with the reported isocyanate quantity. The isocyanate is added to the polyol formulation (efflux time: 3 s). The mixture is subjected to intensive mixing for 5 seconds using a stirring means (Pendraulik). A stopwatch is started at commencement of the mixing and the characteristic reaction times are read-off therefrom. About 93 g of the reaction mixture are poured into a teflon film-lined aluminum box mold having a volume of 1.6 dm.sup.3 and a temperature of 23° C. The mold is closed and locked. After six minutes the mold is unlocked, decompressed and the mold pressure is qualitatively assessed via the height by which the mold lid has been raised by the molding [mm]. The demolded foam cushion is qualitatively assessed for reaction completeness and for skin and pore structure.

[0493] The reaction kinetics are determined using the residual reaction mixture in the beaker.

[0494] The cream time has been attained when an expanding of the mixture is observable.

[0495] The fiber time has been attained when strings can be pulled from the surface of the rising foam by dabbing with a wooden spatula. Alternatively, lumps form on the spatula.

[0496] The rise time has been attained when the foam finally ceases to expand. It should be noted here that some systems have a propensity to undergo some sagging before rising again.

TABLE-US-00003 90V 90A 105V Reaction kinetics Comparative Inventive Comparative Cream time seconds 10 8 10 Fiber time seconds 50 55 52 Rise time seconds 69 80 80

[0497] Conditioning of the Foams:

[0498] After production all foams were stored in a fume cupboard at 20-23° C. for 7 days.

[0499] Some of the foams were packaged in aluminum foil and stored in a circulating air drying cabinet at 90° C. before measurement of the aldehyde emissions. These foams are described as “aged”.

[0500] Mechanical Characterization of the Foams

[0501] The compressive strength was measured at 40% compression parallel to the foaming direction. A pre-loading of 2 kPa was established. The advancing rate was 50 mm/min.

TABLE-US-00004 Comparative Comparative Inventive Apparent density 90V 105V 90A Before ageing 49 50 48 Kg/m.sup.3 After 7 days at 110° C. 49 50 49 Kg/m.sup.3 Compressive strength 90V 105V 90A at 40% compression Before ageing 8.4 11.7 8.7 kPa After 7 days at 110° C. 8.2 11.7 8.6 kPa Damping at 40% 90V 105 V 90A compression Before ageing 0.42 0.47 0.38 After 7 days at 110° C. 0.41 0.47 0.39

[0502] Aldehyde Emissions

[0503] Measurement Method 1 (Bottle Method According to VDA 275):

TABLE-US-00005 90V 105V 90A VDA275 Comparative Comparative Inventive Formaldehyde mg/kg 4.2 3.6 3.8

[0504] The familiar effect that increasing the index reduces aldehyde emissions is observed. At an identical index the foams according to the invention show moderately to markedly reduced aldehyde emissions.

[0505] Test Method 2 (Modified Bottle Method):

TABLE-US-00006 90 V 105V 90 A Formaldehyde Comparative Comparative Inventive Before ageing mg/kg 7.0 6.1 5.3 After 7 days at 90° C. mg/kg 8.8 9.8 7.8

[0506] The modified method increases the visibility of formaldehyde. Surprisingly, the ageing results in a reversing of the initially positive effect of a higher index.

[0507] Before and after aging the addition of cyanoacetic acid has a positive effect on formaldehyde emissions.

[0508] Test Series 2: Semi-Rigid Slabstock Foam, for Example for Sound Absorption

[0509] (Delimitation from EP 1674515)

[0510] Description of Raw Materials [0511] (A1/A2)-1: Polyether mixture of a glycerol/sorbitol-co-started polyalkylene oxide having an equivalent weight of 1.8 kg/mol and an OH number of 31 mg KOH/g, a glycerol-started polyalkylene oxide having an equivalent weight of 0.1 kg/mol and an OH number of 560 mg KOH/g and a propylene glycol-started polyalkylene oxide having an equivalent weight of 0.2 kg/mol and an OH number of 280 mg KOH/g in a weight ratio of 38:50:12. [0512] A2-2: Glycerol [0513] A3-1: Water [0514] A4-5: Polyether-polydimethylsilicone foam stabilizer [0515] A4-6: Catalyst: Reaction product of oleic acid and dimethylaminopropylamine (1:1 molar) [0516] A5-2: Acethydrazide [0517] A5-3: Cyanoacethydrazide [0518] A5-4: DHBH: Reaction product of hydrazine hydrate und cyclic propylene carbonate (1:2 molar) [0519] A5-5: CMPA: 2-cyano-N-methyl-N-phenylacetamide [0520] A5-6: KCA: Potassium cyanoacetate [0521] B-2: Mixture of MDI isomers and homologs having a density of 1.22 kg/l, an isocyanate content of 322 g/kg and a viscosity of 0.05 Pa*s. The content of 4,4′-MDI is 47% by weight. The sum of 2,2′-MDI, 2,4′-MDI and 4,4′-MDI is 70%.

TABLE-US-00007 % by weight in polyol formulation Polyether mixture (A1/A2)-1 82.0 Polyether-polydimethylsilicone 1.5 foam stabilizer A4-5 Crosslinker A2-2 7.0 Blowing agent A3-1 6.5 Catalyst A4-6 3.0

[0522] Additives A5 in Polyol Formulation:

TABLE-US-00008 90 V2 90 V3 90 C 90 D 90 V4 90 V5 90 E 90 F Comparative Inventive Comparative Inventive Type CH.sub.3—CO—NH—NH.sub.2 A5-NC—CH.sub.2—CO—NH—CO—NH.sub.2 A5-DHBH A5- None CMPAA5-KCA A5- 2 3 4 5 6 Content in 7.1 7.1 7.7 7.1 7.7 — 7.7 7.7 g/kg Content in 96 96 61 56 33 — 44 63 mmol/kg Addition as Solution in Solution in Solid Suspension in Liquid Solid Solution in blowing agent crosslinker crosslinker blowing agent

[0523] The content is reported in % by weight. DHBH is the reaction product of hydrazine hydrate and cyclic propylene carbonate (1:2 molar), KCA is potassium cyanoacetate K.sup.+[NC—CH.sub.2—CO.sub.2].sup.−. CMPA is 2-cyano-N-methyl-N-phenylacetamide NC—CH.sub.2—CO—N(CH.sub.3)(C.sub.6H.sub.5)

[0524] All foams are produced with an index of 90.

[0525] Mechanical Characterization of the Foams

TABLE-US-00009 90 V2 90 V3 90 B 90 C 90 V4 90 V5 90D 90 E Comparative Inventive Comparative Inventive Density Kg/ 26 24 24 25 24 21 27 22 m.sup.3 ε 6.6% 6.1% 7.0% 7.4% 5.2% 5.4% 5.3% 3.2% Modulus kPa 103 91 112 122 112 94 122 79 Maximum kPa 82 79 93 101 92 82 124 force

[0526] The compressive strength was measured at 10% compression parallel to the foaming direction.

[0527] The inventive examples show a somewhat higher hardness at slightly better elasticity compared to use of acethydrazide. This is advantageous in use as a core ply in sandwich components such as automotive headlinings.

[0528] The open-cell content was measured with an AccuPyc 1330 gas displacement pycnometer.

TABLE-US-00010 Comparative Inventive Comparative Inventive 90 V2 90 V3 90 B 90 C 90 V4 90 V5 90 D 90 E average value 88% 89% 90% 92% 89% 87% 88% 90%

[0529] The inventive examples show somewhat higher open-cell content compared to use of acethydrazide. This is advantageous for use in sound-absorbing applications.

[0530] Emissions According to Test Method 2 (Modified Bottle Method)

TABLE-US-00011 Comparative Inventive Comparative Inventive 90 V2 90 V3 90 B 90 C 90 V4 90 V5 90 D 90 E Formaldehyde mg/kg 3.7 3.6 0.7 0.3 4.8 4.4 2.2 1.3 Deviation −16% −18% −84% −93% −50% −70% compared to standard ΔFA/Additive mmol/ −7 −8 −61 −73 −49 −49 mol

[0531] The results confirm the literature: Acethydrazide is in principle suitable for reducing the formaldehyde emissions from foams. However, cyanoacetylurea and other derivatives of cyanoacetic acid are significantly more effective.

[0532] In the experiments 90 D and 90 E the acetaldehyde emissions were reduced from 0.6 mg/kg (comparative 90V5) to 0.5 and 0.3 mg/kg respectively.

[0533] Test Series 3: Semi-Rigid Slabstock Foam, for Example for Headlinings

[0534] (Delimitation from EP2138520)

[0535] Description of Raw Materials [0536] (A1/A2)-2: Polyether mixture of a glycerol/sorbitol-co-started polyalkylene oxide having an equivalent weight of 1.8 kg/mol and an OH number of 31 mg KOH/g, a glycerol-started polyalkylene oxide having an equivalent weight of 0.1 kg/mol an OH number of 560 mg KOH/g and a propylene glycol-started polyalkylene oxide having an equivalent weight of 0.2 kg/mol and an OH number of 280 mg KOH/g in a weight ratio of 39:49:12. [0537] A2-2: Glycerol [0538] A3-1: Water [0539] A4-5: Silicone foam stabilizer [0540] A4-6: Reaction product of oleic acid and dimethylaminopropylamine (1:1 molar) [0541] A5-3: Cyanoacethydrazide [0542] A5-7: Cyanoacetamide [0543] B2-2: Mixture of MDI isomers and homologs having a density of 1.22 kg/liter, an isocyanate content of 322 g/kg and a viscosity of 0.05 Pa*s. The content of 4,4′-MDI is 47% by weight. The sum of 2,2′-MDI, 2,4′-MDI and 4,4′-MDI is 70%.

TABLE-US-00012 % by weight in polyol formulation Polyether mixture (A1/A2)-2 82.75 Silicone foam stabilizer A4-5 0.75 Crosslinker A2-2 7.00 Blowing agent A3-1 6.50 Catalyst A4-6 3.00

[0544] Cyanoacetamide is known as a cell opener. It is accordingly not surprising that foams that contained cyanoacetamide were unstable and in one case collapsed. In the case of the foams 80 V2, 90 V6 and 100 V2 the blowing agent content was increased by 0.5 parts by weight and 1.5 parts by weight of Jeffcat DPA were added to obtain an approximately comparable apparent density.

[0545] Usage amounts of additives A5:

[0546] In the comparative tests 80 V1, 90 V6, 110 V1 and 110 V1, no additive was employed.

TABLE-US-00013 80 V2 90 V7 110 V2 80 A 90 F 100 A 110 A Additive Cyanoacetamide (comparative) A5-7 Cyanoacethydrazide (inventive) A5-3 g/kg of foam 8.3 7.7 7.2 8.0 7.4 6.9 6.5 mmol/kg of foam 98 92 86 80 75 70 66

[0547] Kinetic Characterization of the Foams

TABLE-US-00014 Cream time (seconds) Index 80 90 100 110 Designation 80 V1 90 V6 100 V1 110 V1 Additive None Comparative 35 27 25 43 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 22 24 23 Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 22 25 25 28 Fiber time (seconds) Index 80 90 100 110 Designation 80 V1 90 V6 100 V1 110 V1 Additive None Comparative 170 170 175 215 Designation 80 V2 100 V2 Additive Cyanoacetamide Comparative 290 255 Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 180 200 210 225 Rise time (seconds) Index 80 90 100 110 Designation 80 V1 90 V6 100 V1 110 V1 Additive None Comparative 225 267 285 277 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 330 275 300 Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 246 250 255 305

[0548] The test comprising employing cyanoacethydrazide as an additive results in foam collapse at an index of 100. The test with an index of 110 was not performed.

[0549] Mechanical Characterization of the Foams

TABLE-US-00015 Core apparent density in kg/m.sup.3 Index 80 90 100 110 Before ageing Designation 80 V1 90 V6 100 V1 110 V1 Additive None Comparative 25 28 32 32 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 31 31 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 26 30 30 29 Core apparent density in kg/m.sup.3 Index 80 90 100 110 After 7 days at 90° C. Designation 80 V1 90 V6 100 V1 110 V1 Additive None Comparative 28 28 29 29 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 28 30 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 25 28 28 31 Compressive elastic modulus Index 80 90 100 110 in MPa Designation 80 V1 90 V6 100 V1 110 V1 Additive None Comparative 0.11 0.13 0.17 0.17 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 0.14 0.14 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 0.10 0.14 0.15 0.14 Compressive elastic modulus Index 80 90 100 110 in MPa After 7 days at 90° C. Designation 80 V1 90 V6 100 V1 110 V1 Additive None Comparative 0.14 0.13 0.16 0.15 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 0.12 0.15 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 0.10 0.14 0.13 0.17 Open-cell content in % Index 80 90 100 110 Gas displacement pycnometer Designation 80 V1 90 V6 100 V1 110 V1 AccuPyk 1330 Additive None Comparative 47 60 66 69 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 81 88 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 60 52 47 43 Glass transition temperature Index 80 90 100 110 by DSC in ° C. Designation 80 V1 90 V6 100 V1 110 V1 Additive None Comparative 244 204 202 229 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 187 173 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 240 247 228

[0550] Formaldehyde Emissions (all Amounts in Mg/Kg of Foam)

TABLE-US-00016 Before ageing Index 80 90 100 110 Test method 1 Designation 80 V1 90 V6 100 V1 110 V1 Additive None Comparative 1.5 1.1 0.9 1.2 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 0.4 0.3 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 0.2 0.5 0.3 0.2 After 7 days at 90° C. Index 80 90 100 110 Test method 1 Designation 80 V1 90 V6 100 V1 110 V1 Additive None Comparative 3.6 3.2 3.4 3.2 Designation 80 V2 90 V7 100 V2 110 V3 Additive Cyanoacetamide Comparative 1.6 2.5 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 0.9 0.9 1.3 1.2 Before ageing Index 80 90 100 110 Test method 2 Designation 80 V1 90 V6 100 V1 110 V1 Additive None Comparative 4.5 6.1 6.2 6.7 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 0.3 0.5 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 0.5 0.8 0.7 0.6 After 7 days at 90° C. Index 80 90 100 110 Test method 2 Designation 80 V1 90 V6 100 V1 110 V1 Additive None Comparative 15.0 13.6 18.0 13.9 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 3.2 3.9 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 3.0 3.0 3.0 4.3

[0551] Formaldehyde Reduction (all Amounts in Mmol of Formaldehhyde/Mol of Additive)

TABLE-US-00017 Before ageing, test method 1 Index 80 90 100 110 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 11 9 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 16 8 9 15 After 7 days at 90° C. Index 80 90 100 110 Test method 1 Designation 80 V2 90 V7 100 V2 110 V3 Additive Cyanoacetamide Comparative 20 8 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 34 31 30 30 Before ageing, test method 2 Index 80 90 100 110 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 43 61 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 50 71 79 92 After 7 days at 90° C. Index 80 90 100 110 Test method 2 Designation 80 V2 90 V7 100 V2 Additive Cyanoacetamide Comparative 120 105 Collapses Designation 80 A 90 F 100 A 110 A Additive Cyanoacethydrazide Invention 150 141 214 145

[0552] The results confirm the literature: Cyanoacetamide is suitable for reducing formaldehyde emissions.

[0553] It is apparent that cyanoacethydrazide is not only likewise well suited for reducing the formaldehyde emissions. This applies in particular after aging.

[0554] The use of cyanoacethydrazide also makes it possible to produce foams over a wider index range.

[0555] This is of great advantage for industrial use since foams are easier to adapt to customer requirements.

[0556] Test Series 4: Flexible Molded Foam

[0557] (Delimitation from EP2138520).

[0558] Description of Raw Materials [0559] A1-2: Glycerol-started polyalkylene oxide having a molar weight of 6.1 kg/mol, an OH number of 28 mg KOH/g and a content of ethylene oxide of <50% by weight. [0560] A2-3: Diethanolamine [0561] A3-1: Water [0562] A4-2: Tegostab® B8734 LF2 foam stabilizer, commercially available from Evonik Nutrition & Care, Essen [0563] A4-3: Glycerol-started polyalkylene oxide having an OH number of 37 mg KOH/g and a content of ethylene oxide of ≥50% by weight (cell opener) [0564] A4-7: Catalyst mixture of Jeffcat® ZR50 (commercially available from Huntsman) and Dabco® NE 300 (commercially available from Air Products) in a ratio of 4:1 (by weight) [0565] A5-3: Cyanoacethydrazide [0566] A5-7: Cyanoacetamide [0567] B1-3: Mixture of MDI isomers and homologs having a density of 1.24 kg/liter, an isocyanate content of 325 g/kg and a viscosity of 0.03 Pa*s. The content of 4,4′-MDI is 60% by weight. The sum of 2,2′-MDI, 2,4′-MDI and 4,4′-MDI is 83% by weight.

TABLE-US-00018 Comparative Comparative Inventive 90V8 90V9 90G Polyether A1-2 931 931 945 g/kg Cell opener A4-3 19 19 19 g/kg Crosslinker A2-3 11 11 11 g/kg Blowing agent A3-1 33 33 33 g/kg Catalyst A4-7 5 5 5 g/kg Cyanoacetamide A5-7 0 1 0 g/kg Cyanacethydrazide A5-3 0 0 1 g/kg

[0568] The two components A and B were brought to reaction with an index of 100.

[0569] The usage amounts of cyanoacetamide A5-7 and cyanoacethydrazide A5-3 are 7.1 and 6.0 mmol/kg of foam respectively.

[0570] The input materials recited in the examples are reacted with one another in the one-stage process in the manner of processing customary for the production of flexible moulded polyurethane foams in the cold-cure process. The reaction mixture at a temperature of 24° C. is introduced into a metal mold (volume 9.7 dm.sup.3) that has been heated to 60° C. and previously coated with a release agent (PURA E1429H NV (Chem-Trend)). The usage amount is employed according to the desired apparent density and mold volume. The moldings were demolded and wrung-out after 4 minutes.

[0571] After 4 hours the moldings were sealed in aluminum composite film.

[0572] The formaldehyde emissions were determined according to method 2.

TABLE-US-00019 90V8 90V9 90G Comparative Comparative Inventive Formaldehyde 3.0 1.8 1.5 mg/kg Difference compared Reference 1.2 1.5 mg/kg to foam without additive Specific reduction Reference 5.6 8.3 mmol/mol

[0573] The acetaldehyde emissions are 0.6 mg/kg without an additive. Both additives reduce the acetaldehyde emissions to below the limit of detection of 0.3 mg/kg.

[0574] It is apparent here too that cyanoacetamide is suitable for reducing emissions of formaldehyde.

[0575] Here too, cyanacethydrazide is even more effective.