PRODUCTION OF PU FOAMS USING RECYCLED POLYOLS
20240368332 · 2024-11-07
Assignee
Inventors
Cpc classification
C08G18/4829
CHEMISTRY; METALLURGY
C08J9/02
CHEMISTRY; METALLURGY
C08G18/7621
CHEMISTRY; METALLURGY
C08G18/18
CHEMISTRY; METALLURGY
International classification
C08G18/18
CHEMISTRY; METALLURGY
C08J9/00
CHEMISTRY; METALLURGY
C08J9/02
CHEMISTRY; METALLURGY
Abstract
A process for producing polyurethane foams is developed by reacting at least one polyol component that includes recycled polyol with at least one isocyanate component, in the presence of one or more catalysts that catalyse the isocyanate-polyol and/or isocyanate-water and/or isocyanate trimerization reactions, at least one foam stabilizer and optionally one or more chemical or physical blowing agents. The polydispersity of the respective recycled polyol is <2. A composition is made that is suitable for production of a polyurethane foam, including at least one polyol component, at least one isocyanate component, a catalyst, a foam stabilizer, a blowing agent and optionally auxiliaries. The at least one polyol component includes a recycled polyol with a polydispersity of <2. A polyurethane foam is made using the above process, and a process is developed for manufacturing goods that include the polyurethane foam.
Claims
1. A process for producing polyurethane foams, comprising: reacting (a) at least one polyol component, comprising a recycled polyol, (b) at least one isocyanate component, in the presence of (c) one or more catalysts that catalyse isocyanate-polyol and/or isocyanate-water and/or isocyanate trimerization reactions, (d) at least one foam stabilizer and also (e) optionally one or more chemical or physical blowing agents, wherein a polydispersity of the recycled polyol is <2.
2. The process according to claim 1, wherein the at least one polyol component further comprises one or more further polyols, wherein a polydispersity of the one or more further polyols, where said further polyols make up at least 5% by weight of the proportion of total polyol, is likewise <2, with the proviso that the polydispersity of the recycled polyol is not more than 0.3 higher than the polydispersity of the one or more further polyols.
3. The process according to claim 1, wherein the polyurethane foam is at least one selected from the group consisting of a rigid PU foam, a flexible PU foam, a hot-cure flexible PU foam, a viscoelastic PU foam, an HR PU foam, a hypersoft PU foam, a semirigid PU foam, a thermoformable PU foam and an integral PU foam.
4. The process according to claim 1, wherein the reaction is carried out using f) water, g) one or more organic solvents, h) one or more stabilizers against oxidative degradation, i) one or more flame retardants, and/or j) one or more further additives.
5. The process according to claim 1, wherein the foam stabilizer is one or more silicon compounds that include carbon atoms as described by the formula (1c) and mixtures of two or more of said compounds:
[R.sup.1.sub.2R.sup.2SiO.sub.1/2].sub.a[R.sup.1.sub.3SiO.sub.1/2].sub.b[R.sup.1.sub.2SiO.sub.2/2].sub.c[R.sup.1R.sup.2SiO.sub.2/2].sub.d[R.sup.3SiO.sub.3/2].sub.e[SiO.sub.4/2].sub.fG.sub.gFormula (1c): with a=0 to 12, b=0 to 8, c=0 to 250, d=0 to 40, e=0 to 10, f=0 to 5, g=0 to 3, where:
(O.sub.1/2).sub.nSiR.sup.1.sub.mCH.sub.2CHR.sup.5R.sup.4CHR.sup.5CH.sub.2SiR.sup.1.sub.m(O.sub.1/2).sub.n,
(O.sub.1/2).sub.nSiR.sup.1.sub.mCH.sub.2CHR.sup.5R.sup.4CR.sup.5CH.sub.2,
(O.sub.1/2).sub.nSiR.sup.1.sub.mCH.sub.2CHR.sup.5R.sup.4CR.sup.5CR.sup.5CH.sub.3, R.sup.4=independently identical or different divalent organic radicals, preferably divalent organic radicals of 1 to 50 carbon atoms, optionally interrupted by ether, ester or amide groups and optionally functionalized with OH groups, or (SiR.sup.1.sub.2O).sub.xSiR.sup.1.sub.2 groups, R.sup.5=independently identical or different alkyl radicals consisting of 1 to 16 carbon atoms, aryl radicals having 6 to 16 carbon atoms or hydrogen where: n=1 or 2, m=1 or 2, n+m=3, R.sup.1=identical or different radicals selected from the group of saturated or unsaturated alkyl radicals having 1 to 16 carbon atoms or aryl radicals having 6 to 16 carbon atoms or hydrogen or OR.sup.6, R.sup.2=independently identical or different polyethers obtainable by the polymerization of ethylene oxide and/or propylene oxide and/or other alkylene oxides such as butylene oxide or styrene oxide having the general formula (2) or an organic radical corresponding to formula (3)
(R.sup.7).sup.hO[C.sub.2H.sub.4O].sub.i[C.sub.3H.sub.6O].sub.j[CR.sup.8.sub.2CR.sup.8.sub.2O].sub.kR.sup.9,(2)
O.sub.hR.sup.10,(3) where h=0 or 1, R.sup.7=divalent organic radical, preferably divalent organic alkyl or aryl radical optionally substituted with OR.sup.6, i=0 to 150, j=0 to 150, k=0 to 80, p=1-18, where
6. The process according to claim 1, wherein the catalyst for production of the PU foam is at least one selected from the group consisting of triethylenediamine, 1,4-diazabicyclo[2.2.2]octane-2-methanol, diethanolamine, N-[2-[2-(dimethylamino)ethoxy]ethyl]-N-methyl-1,3-propanediamine, 2-[[2-(2-(dimethylamino)ethoxy)ethyl]methylamino]ethanol, 1,1-[(3-{bis[3-(dimethylamino)propyl]amino}propyl)imino]dipropan-2-ol, [3-(dimethylamino)propyl]urea, 1,3-bis[3-(dimethylamino)propyl]urea, and amine catalysts of general structure (1a) and/or of structure (1b): ##STR00003## wherein X comprises oxygen, nitrogen, hydroxyl, amino groups of the structure NR.sup.III or NR.sup.IIIR.sup.IV, or urea groups (N(R.sup.V)C(O)N(R.sup.VI) or N(R.sup.VII)C(O)NR.sup.VIR.sup.VII), Y comprises amino groups NR.sup.VIIIR.sup.IX or alkoxy groups OR.sup.IX, R.sup.I,II comprise identical or different, linear or cyclic, aliphatic or aromatic hydrocarbon groups having 1-8 carbon atoms that are optionally functionalized with an OH group and/or comprise hydrogen, R.sup.III-IX comprise identical or different, linear or cyclic, aliphatic or aromatic hydrocarbon groups having 1-8 carbon atoms that are optionally functionalized with an OH group, an NH or NH.sub.2 group and/or comprise hydrogen, m=0 to 4, n=2 to 6, i=0 to 3, ##STR00004## R.sup.X comprises at least one identical or different radicals selected from the group consisting of hydrogen and/or linear, branched or cyclic, aliphatic, and aromatic hydrocarbon groups having 1-18 carbon atoms, which may be substituted with 0-1 hydroxyl groups and 0-1 NH.sub.2 groups, Z comprises oxygen, NR.sup.X or CH.sub.2, and/or metal compounds selected from the group consisting of organometallic metal salts, organic metal salts, inorganic metal salts, organometallic compounds of the metals Sn, Bi, Zn, Al or K, and mixtures thereof.
7. The process according to claim 1, wherein, based on a total employed polyol component, more than 30% by weight of recycled polyol having a polydispersity of <2 is used.
8. The process according to claim 1, wherein the recycled polyol is a recycled polyol produced from polyurethane waste, the recycled polyol and/or recycled polymer having been obtained by solvolysis.
9. The process according to claim 1, wherein the recycled polyol was obtained from a polyurethane hydrolysis comprising the reaction of the polyurethane with water in the presence of a base-catalyst combination (I) or (II), where (I) comprises a base having a pK.sub.b at 25 C. of 1 to 10 and at least one catalyst selected from the group consisting of quaternary ammonium salts containing an ammonium cation comprising 6 to 30 carbon atoms and an organic sulfonate containing at least 7 carbon atoms, or where (II) comprises a base having a pK.sub.b at 25 C. of <1 and at least one catalyst selected from the group consisting of quaternary ammonium salts containing an ammonium cation having 6 to 14 carbon atoms in the case the ammonium cation does not contain a benzyl substituent, and quaternary ammonium salts containing an ammonium cation having 6 to 12 carbon atoms in the case the ammonium cation contains a benzyl substituent.
10. The process according to claim 1, wherein the recycled polyol was obtained from recycling of a polyurethane, a polydispersity of the resulting recycled polyol being not more than 0.5 higher than a polydispersity of the original polyols of the original polyurethane from which the recycled polyol is obtained.
11. A composition suitable for production of a polyurethane foam, comprising at least one polyol component, at least one isocyanate component, a catalyst, a foam stabilizer, a blowing agent and optionally auxiliaries, wherein the polyol component comprises a recycled polyol, wherein a polydispersity of said recycled polyol is <2.
12. The composition according to claim 11, wherein, based on a total polyol component, more than 30% by weight of the recycled polyol having a polydispersity of <2 is present.
13. A polyurethane foam, obtained by the process according to claim 1.
14. A process of manufacturing goods, comprising: incorporating the polyurethane foam according to claim 13 into at least one selected from the group consisting of refrigerator insulation, insulation panels, sandwich elements, pipe insulation, imitation wood, mattresses, furniture cushioning, automotive seat cushioning, headrests, instrument panels, automotive interior trim, automotive headlining, sound absorption material, steering wheels, shoe soles, carpet backing foam, and filter foam.
15. The process according to claim 1, wherein the polydispersity of the recycled polyol is 1.2.
16. The process according to claim 1, wherein the at least one polyol component further comprises one or more further polyols, wherein a polydispersity of the one or more further polyols, where said further polyols make up at least 20% by weight of the proportion of total polyol, is likewise 1.2, with the proviso that the polydispersity of the recycled polyol is not more than 0.1, higher than the polydispersity of the one or more further polyols.
17. The process according to claim 1, wherein the polyurethane foam is at least one selected from the group consisting of a hot-cure flexible PU foam, a HR PU foam, a hypersoft PU foam and a viscoelastic PU foam.
18. The process according to claim 1, wherein the polyurethane foam is a hot-cure flexible PU foam.
19. The process according to claim 1, wherein the reaction is carried out using f) water, g) one or more organic solvents, h) one or more antioxidants, i) one or more flame retardants, and/or j) one or more further additives.
Description
EXAMPLES
Production of Flexible PU Foams
[0171] To test the recycled polyols in respect of their foaming properties and their influence on the physical properties of the foam, the following formulation was used for producing the hot-cure flexible foam. This means, for example, that 1.0 part (1.0 pphp) of a component refers to 1 g of said substance per 100 g of polyol.
TABLE-US-00002 TABLE 1 Formulation for production of hot-cure flexible PU foams Formulation 1 Parts by mass (pphp) Polyol.sup.1) 100 pphp Water 4.00 pphp Kosmos T9.sup.2) 0.20 pphp Dabco DMEA.sup.3) 0.15 pphp Tegostab BF2370.sup.4) 1.0 pphp Desmodur T 80.sup.5) Variable, constant index .sup.1)Polyol: Standard polyether polyol Arcol 1104 obtainable from Covestro; this is a glycerol-based polyether polyol having an OH value of 56 mg KOH/g and a number-average molar mass of 3000 g/mol or recycled polyols of the invention or non-inventive recycled polyol. The recycled polyols are produced from hot-cure flexible PU foams via a chemical recycling process. The recycling processes respectively used for production of the recycled polyol of the invention and of the non-inventive recycled polyol are described in the following section. .sup.2)Kosmos T9, obtainable from Evonik Industries: tin(II) salt of 2-ethylhexanoic acid. .sup.3)Dabco DMEA: dimethylethanolamine, available from Evonik Industries. Amine catalyst for production of polyurethane foams .sup.4)Polyether-modified polysiloxane, available from Evonik Industries. .sup.5)Toluene diisocyanate T 80 (80% 2,4-isomer, 20% 2,6-isomer) from Covestro, 3 mPa .Math. s, 48% NCO, functionality 2.
GPC Measurements for Determining the Polydispersity of Polyols
[0172] The polydispersity and average molecular weights M.sub.n and M.sub.w of the recycled polyols were determined by gel-permeation chromatography based on ISO 13885-1:2020 under the following conditions: Separation column combination SDV 1000/10000 with guard column (length 65 cm, column temperature 30 C.), THF as mobile phase, flow rate 1 ml/min, sample concentration 10 g/l, injected volume 20 l, refractive index detector (RI detector) at 30 C., calibration with polystyrene (162-2 520 000 g/mol). The values obtained are polystyrene mass equivalents.
Production of the Recycled Polyols
Recycled Polyol 1 (Non-Inventive)
[0173] The non-inventive recycled polyol 1 was produced according to a procedure from H&S Anlagentechnik from 2012: https://www.dbu.de/OPAC/ab/DBU-Abschlussbericht-AZ-29395.pdf.
[0174] A reactor from Parr (Parr Instrumental Company) equipped with a glass inner container and a mechanical stirrer was filled with 300.2 g of compressed PU foam pieces (approx. 1 cm1 cm). The polyurethane foam used was produced according to formulation 1, in which the conventional polyol Arcol 1104 had been used. To the foam pieces was then added 152.64 g of the polyol Arcol 1104, 75.63 g of phthalic acid and 11.97 g of aqueous hydrogen peroxide solution (30% in water). The reaction mixture was heated to 250 C. and held within a temperature range of 237 C. and 256 C. for five hours. At the end of the reaction time, the heating was switched off and, on reaching a reaction temperature of 160 C., a second portion of 140.63 g of Arcol 1104 was added under a nitrogen counterflow. The liquid reaction mixture was cooled to room temperature and, after decanting, was used as recycled polyol 1 having a polydispersity of 4.38 The recycling process was repeated so as to provide a sufficiently large amount of recycled polyol for the foaming experiments
Recycled Polyol 2 (Inventive)
[0175] The recycled polyol 2 of the invention was obtained by hydrolysis of polyurethane in the presence of a saturated K.sub.2CO.sub.3 solution and tetrabutylammonium hydrogen sulfate as catalyst:
[0176] A reactor from Parr (Parr Instrumental Company) equipped with a PTFE inner container and a mechanical stirrer was filled with 25 g of compressed foam pieces (approx. 1 cm1 cm). The polyurethane foam used was produced according to formulation 1, in which the conventional polyol Arcol 1104 had been used. To this was then added 75 g of saturated K.sub.2CO.sub.3 solution (pK.sub.b 3.67 at 25 C.). The tetrabutylammonium hydrogen sulfate catalyst was then added to a content of 5% by weight based on the mass of the reaction mixture. The reactor was closed and the reaction mixture was heated to an internal temperature of 150 C. for 14 hours. At the end of the 14 hours, heating was stopped and the reaction mixture was cooled to room temperature. After opening the reactor, the reaction mixture was transferred to a round-bottomed flask. The water was removed by rotary evaporation and the residual reaction mixture was extracted with cyclohexane. The cyclohexane solution was washed with 1 N aqueous HCl solution and then dried over magnesium sulfate. Removal of the cyclohexane by rotary evaporation afforded the recycled polyol 2 having a polydispersity of 1.07 in the form of a liquid. The hydrolysis process was repeated so as to provide a sufficiently large amount of recycled polyol for the foaming experiments.
Recycled Polyol 3 (Inventive)
[0177] The recycled polyol 3 of the invention was obtained by hydrolysis of polyurethane in the presence of a 20% sodium hydroxide solution and tributylmethylammonium chloride as catalyst:
[0178] A reactor from Parr (Parr Instrumental Company) equipped with a PTFE inner container and a mechanical stirrer was filled with 25 g of compressed foam pieces (approx. 1 cm1 cm). The polyurethane foam used was produced according to formulation 1, in which the conventional polyol Arcol 1104 had been used. To this was then added 75 g of sodium hydroxide solution (20% by weight solution in water).
[0179] The tributylmethylammonium chloride catalyst was then added to a content of 2.5% by weight based on the mass of the reaction mixture. The reactor was closed and the reaction mixture was heated to an internal temperature of 130 C. for 14 hours. At the end of the 14 hours, heating was stopped and the reaction mixture was cooled to room temperature. After opening the reactor, the reaction mixture was transferred to a round-bottomed flask. The water was removed by rotary evaporation and the residual reaction mixture was extracted with cyclohexane. The cyclohexane phase was washed with 1 N aqueous HCl solution and then dried over magnesium sulfate. Removal of the cyclohexane by rotary evaporation afforded the recycled polyol 3 having a polydispersity of 1.06 in the form of a liquid, and this was used for foaming experiments. The hydrolysis process was repeated so as to provide a sufficiently large amount of recycled polyol for the foaming experiments.
General Procedure for Production of Hot-Cure Flexible PU Foams
[0180] The polyurethane foams were produced in the laboratory in the form of what are called handmade foams. The production of the foams was carried out at 22 C. and air pressure of 762 mmHg according to the details below. The polyurethane foams according to formulation 1 were in each case produced using either 300 or 400 g of polyol. The other formulation constituents were adjusted accordingly. This meant, for example, that 1.0 part (1.0 pphp) of a component refers to 1 g of said substance per 100 g of polyol.
[0181] For the foams according to formulation 1, a paper cup was initially charged with the tin catalyst tin(II) 2-ethylhexanoate, polyol, the water, the amine catalysts and the respective foam stabilizer, and the contents were mixed with a disc stirrer at 1000 rpm for 60 s. After the first stirring, the isocyanate was added and incorporated with the same stirrer at 2500 rpm for 7 s and the reaction then immediately transferred to a paper-lined box (30 cm30 cm base area and 30 cm height). After the foam had been poured in, it rose up in the foaming box. In the ideal case, the foam blew off on reaching the maximum rise height and then receded slightly. This opened the cell membranes of the foam bubbles to afford an open-pore cell structure in the foam.
[0182] To assess the properties, the following characteristic parameters were in the following section determined.
Performance Tests
[0183] The foams produced were assessed on the basis of the following physical properties [0184] a) Settling of the foam at the end of the rise phase (=fall-back): [0185] The settling, or the further rise, is calculated as the difference in the foam height immediately after blow-off and after 3 minutes after foam blow-off. The foam height is measured at the maximum in the centre of the foam crest by means of a needle secured to a centimetre scale. A positive value here describes the settling of the foam after blow-off; a negative value correspondingly describes the further rise of the foam [0186] b) Foam height is the height of the freely risen foam formed after 3 minutes. The foam height is reported in centimetres (cm). [0187] c) Rise time [0188] The period of time between the end of mixing of the reaction components and the blow-off of the polyurethane foam. The rise time is reported in seconds (s). [0189] d) Porosity [0190] The air permeability of the foam was determined based on DIN EN ISO 4638:1993-07 by a dynamic pressure measurement on the foam. The measured dynamic pressure was reported in mm water column, lower dynamic pressure values being characteristic of a more open foam. The values were measured within a range from 0 to 300 mm water column. The dynamic pressure was measured by means of an apparatus comprising a nitrogen source, reducing valve with pressure gauge, flow-regulating screw, wash bottle, flowmeter, T-piece, applicator nozzle and a graduated glass tube filled with water. The applicator nozzle has an edge length of 100100 mm, a weight of 800 g, an internal diameter at the outlet opening of 5 mm, an internal diameter at the lower applicator ring of 20 mm and an external diameter at the lower applicator ring of 30 mm. [0191] The measurement is carried out by setting the nitrogen inlet pressure to 1 bar by adjusting the reducing valve and setting the flow rate to 480 l/h. The amount of water in the graduated glass tube is set so that no pressure difference builds up and none can be read off. For the measurement on the test specimen having dimensions of 25025050 mm, the applicator nozzle is applied to the corners of the test specimen, flush with the edges, and also once to the (estimated) centre of the test specimen (in each case on the side having the greatest surface area). The result is read off when a constant dynamic pressure has been established. The evaluation is based on the calculated average of the five measurements obtained. [0192] e) Number of cells per cm (cell count): This is determined visually on a cut surface (measured to DIN EN 15702.2009-04). [0193] f) Hardness CLD 40% to DIN EN ISO 3386-1:1997+A1:2010 Measured values are reported in kilopascals (kPa). [0194] g) Compression set [0195] Five test specimens having dimensions of 5 cm5 cm2.5 cm were in each case cut out of the finished foams. The starting thickness was measured. Compression set was measured no earlier than 72 h after production in accordance with DIN EN ISO 1856:2018-11. The test specimens were placed between the plates of the deforming device and were compressed by 90% of their thickness (i.e. to 2.5 mm). Within 15 minutes, the test specimens were placed in an oven at 70 C. and left therein for 22 h. At the end of this time, the apparatus was removed from the oven, the test specimens were removed from the apparatus within 1 min, and they were placed on a wood surface. After relaxing for 30 min, the thickness was measured again and the compression set was calculated. The results are reported in percent according to the following formula. DVR=(d0dr)/d0100% [0196] h) Tensile strength and elongation at break to DIN EN ISO 1798: 2008-2008-04. Measured values for tensile strength are reported in kilopascals (kPa) and measured values for elongation at break in percent (%). [0197] i) Rebound resilience to DIN EN ISO 8307:2008-03. Measured values are reported in percent (%).
Results of the Foamings
[0198] The recycled polyols 2 and 3 and the non-inventive recycled polyol 1 are tested in formulation 1, Table 1, versus the conventional polyol Arcol 1104 The results of the performance tests for the use of the various polyols are given in Tables 2 and 3.
TABLE-US-00003 TABLE 2 Foaming results for the hot-cure flexible PU foams produced according to formulation 1, Table 1, using recycled polyols 1 and 2 and the conventional polyol Arcol 1104. 400 g of polyol was used in each case. The other formulation constituents were recalculated accordingly. Foam specimen #1 #2 #3 #4 #5 Arcol 1104, OH value 56, 100 70 70 reference, polydispersity 1.14, (pphp) Recycled polyol 1 (non- 100 30 inventive), OH value 82 mg/KOH/g, polydispersity 4.38, (pphp) Recycled polyol 2 (inventive), 100 30 OH value 55 mg KOH/g, polydispersity 1.07, (pphp) Index 105 105 105 105 105 Rise time (s) 122 123 122 129 Foam height (cm) 33.2 30.4 32.8 29.4 Settling (cm) 0.3 0.1 0.2 0.1 Cell count (cm.sup.1) 12 12 12 12 Porosity (mm water column) 14 14 15 89 Hardness CLD 40% (kPa) 3.5 3.0 3.4 2.5 Elongation at break (%) 143 180 140 124 Tensile strength (kPa) 118 136 125 110 Rebound resilience (%) 38 38 38 34 Compression set 90%, 22 h 6 8 6 12 at 70 C. (%) Comments Standard Collapse* Standard Standard Standard foam foam foam foam *collapse/collapsed foams are understood as meaning ones that fall in on themselves during foam formation.
[0199] The results in Table 2 show that, when using 100 pphp of recycled polyol 2 of the invention, the foam during production exhibits foaming behaviour comparable to that when 100 pphp of Arcol 1104 is used. Similarly, the physical foam propertiesporosity, cell count, rebound resilience and compression setof foam #3 produced from 100 pphp of recycled polyol 2 are comparable to reference foam #1 based on 100 pphp of Arcol 1104. For the physical foam properties elongation at break and tensile strength, measured values even better than those of reference foam #1 were obtained. Only the hardness showed a slightly lower value, in the case of foam #3 with recycled polyol 2. In contrast, when 100 pphp of non-inventive recycled polyol 1 was used, it was not possible to obtain a standard foam. Foam #2 collapsed completely. Only when using a reduced amount of 30 pphp of recycled polyol in combination with 70 pphp of the conventional polyol Arco 1104 was an evaluable foam obtained (foam #5) However, even when using a reduced amount of 30 pphp of recycled polyol 2, the physical foam propertiesporosity, hardness, elongation at break, tensile strength, rebound resilience and compression setare poorer by comparison with reference foam
TABLE-US-00004 TABLE 3 Foaming results for the hot-cure flexible PU foams produced according to formulation 1, Table 1, using recycled polyols 1 and 3 and the conventional polyol Arcol 1104. A total of 300 g of polyol was used. The other formulation constituents were recalculated accordingly. Foam specimen #6 #7 #8 Arcol 1104, OH value 56, 100 reference, polydispersity 1.14, (pphp) Recycled polyol 1 (non- 100 inventive), OH value 82 mg KOH/g, polydispersity 4.38, (pphp) Recycled polyol 3 (inventive), 100 OH value 54 mg KOH/h, polydispersity 1.06, (pphp) Index 105 105 105 Rise time (s) 117 122 Foam height (cm) 24.0 24.1 Settling (cm) 0.2 0.2 Cell count (cm.sup.1) 14 14 Porosity (mm water column) 15 10 Hardness CLD 40% (kPa) 3.4 3.5 Elongation at break (%) 160 150 Tensile strength (kPa) 113 116 Rebound resilience (%) 43 43 Compression set 90%, 22 h 5 7 at 70 C. (%) Comments Standard Collapse Standard foam foam
[0200] The results in Table 3 show that, when using 100 pphp of recycled polyol 3 of the invention, the foam during production exhibits foaming behaviour comparable to that when 100 pphp of Arcol 1104 is used. Similarly, the physical foam propertiesporosity, cell count, elongation at break, tensile strength, rebound resilience and compression setof foam #8 produced from 100 pphp of recycled polyol 3 are comparable to reference foam #6 based on 100 pphp of Arcol 1104. The hardness showed a slightly higher value in the case of foam #8 with recycled polyol 3. In contrast, when 100 pphp of non-inventive recycled polyol 1 was used, it was not possible to obtain a standard foam. Foam #7 collapsed completely.