PROCESS OF PRODUCING A POLYOL COMPOSITION CONTAINING POLYOLS RELEASED FROM WASTE POLYURETHANE

Abstract

The invention relates to a process for producing a polyol composition containing polyols released from polyurethane waste, and also to a polyol composition produced using this process, and to the use thereof.

Claims

1. A process for producing a polyol composition containing polyols released from polyurethane waste, wherein, in a reaction mixture: (a) polyurethane waste is reacted with; (b) one or more compounds selected from the group consisting of; polyether polyols having an average molar mass of 200 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4, and polyester polyols having an average molar mass of 250 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4, (c) one or more compounds selected from the group consisting of dicarboxylic anhydrides and dicarboxylic acids; and (d) water, forming a polyol composition containing polyols released from the polyurethane waste.

2. The process as claimed in claim 1, wherein: the compounds (b) from the group of the polyether polyols have an average molar mass in the range from 200 g/mol to 6000 g/mol; and the compounds (b) from the group of the polyester polyols have an average molar mass in the range from 350 g/mol to 6000 g/mol.

3. The process as claimed in claim 1, wherein at least one of: the compounds (c) from the group consisting of dicarboxylic anhydrides and dicarboxylic acids are selected from the group consisting of adipic acid and the anhydrides of maleic acid, phthalic acid, hexahydrophthalic acid and succinic acid; and the reaction mixture includes one or more monocarboxylic acids.

4. The process as claimed in one of claim 1, wherein a mixture comprising: (b) the one or more compounds selected from the group consisting of; polyether polyols having an average molar mass of 200 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4, and polyester polyols having an average molar mass of 250 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4; (c) the one or more compounds selected from the group consisting of dicarboxylic anhydrides and dicarboxylic acids, and optionally one or more monocarboxylic acids; and (d) the water is initially charged and heated to a temperature of 130° C. to 230° C.; the polyurethane waste (a) is metered into this mixture such that the reaction mixture is formed, wherein the temperature is kept in the range from 130° C. to 230° C.; in parallel with the metering-in of the polyurethane waste (a), further water (d) is added in one or more portions, or continuously; the reaction mixture is kept at a temperature in the range from 150° C. to 240° C., for 1 to 5 hours; a further portion of the one or more compounds (c) from the group consisting of dicarboxylic anhydrides and dicarboxylic acids is added; following the addition of the further portion of the one or more compounds (c), the reaction mixture is kept at a temperature in the range from 170° C. to 240° C. for 0.5 to 3 hours; and thereafter, the reaction mixture is cooled.

5. The process as claimed in claim 1, wherein: (e) one or more compounds selected from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are added to the reaction mixture.

6. The process as claimed in claim 5, wherein the compounds (e) from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, 1,3-propaneglycol, 1,2-butanediol, 1,4-butaneglycol and glycerol.

7. The process as claimed in claim 5, wherein a mixture comprising: (b) the one or more compounds selected from the group consisting of; polyether polyols having an average molar mass of 200 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4, and polyester polyols having an average molar mass of 250 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4; (c) the one or more compounds selected from the group consisting of dicarboxylic anhydrides and dicarboxylic acids, and optionally one or more monocarboxylic acids; and (d) the water is initially charged and heated to a temperature of 130° C. to 230° C.; the polyurethane waste (a) is metered into this mixture such that the reaction mixture is formed, wherein the temperature is kept in the range from 130° C. to 230° C.; in parallel with the metering-in of the polyurethane waste (a), further water (d) is added in one or more portions, or continuously; one or more compounds (e) selected from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are added if the polyurethane waste (a) has been metered in at least to a third, preferably to a half, and has dissolved; or one or more compounds (e) from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are added if the polyurethane waste (a) has completely dissolved; the reaction mixture is kept at a temperature in the range from 150° C. to 240° C. for 1 to 5 hours; a further portion of the one or more compounds (c) selected from the group consisting of dicarboxylic anhydrides and dicarboxylic acids is added; and following the addition of the further portion of the one or more compounds (c), the reaction mixture is cooled or is kept at a temperature in the range from 150° C. to 240° C. for 0.25 to 1.5 hours; and is cooled thereafter.

8. The process as claimed in claim 5, wherein a mixture comprising (b) the one or more compounds selected from the group consisting of; polyether polyols having an average molar mass of 200 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4, and polyester polyols having an average molar mass of 250 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4, (c) the one or more compounds selected from the group consisting of dicarboxylic anhydrides and dicarboxylic acids, and optionally one or more monocarboxylic acids; and (d) the water is initially charged and heated to a temperature of 130° C. to 230° C.; the polyurethane waste (a) is metered into this mixture such that the reaction mixture is formed, wherein the temperature is kept in the range from 130° C. to 230° C.; in parallel with the metering-in of the polyurethane waste (a), further water (d) is added in one or more portions, or continuously; the reaction mixture is kept at a temperature in the range from 150° C. to 240° C. for 1 to 5 hours; a further portion of the one or more compounds (c) from the group consisting of dicarboxylic anhydrides and dicarboxylic acids is added; following the addition of the further portion of the one or more compounds (c), the reaction mixture is kept at a temperature in the range from 170° C. to 240° C. for 0.25 to 1.5 hours; one or more compounds (e) selected from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are added; following the addition of the one or more compounds (e), the reaction mixture is kept at a temperature in the range from 170° C. to 240° C. for 0.25 to 1.5 hours; and thereafter, the reaction mixture is cooled.

9. The process as claimed in claim 5, wherein a mixture comprising: (b) the one or more compounds selected from the group consisting of; polyether polyols having an average molar mass of 200 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4, and polyester polyols having an average molar mass of 250 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4; (c) the one or more compounds selected from the group consisting of dicarboxylic anhydrides and dicarboxylic acids, and optionally one or more monocarboxylic acids; and (d) the water is initially charged and heated to a temperature of 130° C. to 230° C.; the polyurethane waste (a) is metered into this mixture such that the reaction mixture is formed, wherein the temperature is kept in the range from 130° C. to 230° C.; in parallel with the metering-in of the polyurethane waste (a), further water (d) is added in one or more portions, or continuously; one or more compounds (e) selected from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are added if the polyurethane waste (a) has been metered in at least to a third and has dissolved; or the one or more compounds (e) selected from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are added if the polyurethane waste (a) has completely dissolved; the reaction mixture is kept at a temperature in the range from 150° C. to 240° C. for 1 to 5 hours; a further portion of the one or more compounds (c) selected from the group consisting of dicarboxylic anhydrides and dicarboxylic acids is added; following the addition of the further portion of the one or more compounds (c), the reaction mixture is kept at a temperature in the range from 170° C. to 240° C. for 0.25 to 1.5 hours; a further portion of the one or more compounds (e) selected from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms is added; following the addition of the further portion of one or more compounds (e), the reaction mixture is kept at a temperature in the range from 170° C. to 240° C. for 0.25 to 1.5 hours; and thereafter, the reaction mixture is cooled.

10. The process as claimed in claim 4, wherein, upon cooling the reaction mixture, adding a further portion of (b) the compounds selected from the group consisting of; polyether polyols having an average molar mass of 200 to 8000 g/mol and a hydroxyl functionality of 2 to 4; and polyester polyols having an average molar mass of 250 to 8000 g/mol and a hydroxyl functionality of 2 to 4.

11. The process as claimed in claim 1, wherein at least one of: (a) the polyurethane waste is added in a total amount of 30 wt % to 60 wt %; (b) the compounds selected from the group consisting of polyether polyols and polyester polyols are added in a total amount of 20 wt % to 60 wt %; (c) the compounds selected from the group consisting of dicarboxylic anhydrides and dicarboxylic acids and monocarboxylic acids are added in a total amount of 5 wt % to 20 wt %; (d) the water is added in an amount of 0.2 wt % to 10 wt; and (e) optional compounds selected from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are added in a total amount of 1 wt % to 30 wt %; in each case relative to the total mass of the reactants (a), (b), (c), (d) and (e) as 100 wt %.

12. The process as claimed in claim 1, wherein at least one of: no radical formers are added; and one or more antioxidants are added to the compounds (b) from the group of the polyether polyols.

13. A polyol composition produced according to claim 1.

14. Using a polyol composition produced according to claim 1 to make polyurethanes.

15. The process as claimed in claim 2, wherein at least one of: the compounds (c) from the group consisting of dicarboxylic anhydrides and dicarboxylic acids are selected from the group consisting of adipic acid and the anhydrides of maleic acid, phthalic acid, hexahydrophthalic acid and succinic acid; and the reaction mixture also contains, in addition to the one or more compounds (c) from the group consisting of dicarboxylic anhydrides and dicarboxylic acids, one or more monocarboxylic acids.

16. The process as claimed in claim 6, wherein a mixture comprising: (b) the one or more compounds selected from the group consisting of; polyether polyols having an average molar mass of 200 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4, and polyester polyols having an average molar mass of 250 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4; (c) the one or more compounds selected from the group consisting of dicarboxylic anhydrides and dicarboxylic acids, and optionally one or more monocarboxylic acids; and (d) the water is initially charged and heated to a temperature of 130° C. to 230° C.; the polyurethane waste (a) is metered into this mixture such that the reaction mixture is formed, wherein the temperature is kept in the range from 130° C. to 230° C.; in parallel with the metering-in of the polyurethane waste (a), further water (d) is added in one or more portions, or continuously; one or more compounds (e) selected from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are added if the polyurethane waste (a) has been metered in at least to a third and has dissolved; or one or more compounds (e) from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are added if the polyurethane waste (a) has completely dissolved; the reaction mixture is kept at a temperature in the range from 150° C. to 240° C. for 1 to 5 hours; a further portion of the one or more compounds (c) selected from the group consisting of dicarboxylic anhydrides and dicarboxylic acids is added; and following the addition of the further portion of the one or more compounds (c), the reaction mixture is cooled or is kept at a temperature in the range from 150° C. to 240° C. for 0.25 to 1.5 hours, and is cooled thereafter.

17. The process as claimed in claim 6, wherein a mixture comprising (b) the one or more compounds selected from the group consisting of; polyether polyols having an average molar mass of 200 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4, and polyester polyols having an average molar mass of 250 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4, (c) the one or more compounds from the group consisting of dicarboxylic anhydrides and dicarboxylic acids, and optionally one or more monocarboxylic acids; and (d) the water is initially charged and heated to a temperature of 130° C. to 230° C.; the polyurethane waste (a) is metered into this mixture such that the reaction mixture is formed, wherein the temperature is kept in the range from 130° C. to 230° C.; in parallel with the metering-in of the polyurethane waste (a), further water (d) is added in one or more portions, or continuously; the reaction mixture is kept at a temperature in the range from 150° C. to 240° C. for 1 to 5 hours; a further portion of the one or more compounds (c) from the group consisting of dicarboxylic anhydrides and dicarboxylic acids is added; following the addition of the further portion of the one or more compounds (c), the reaction mixture is kept at a temperature in the range from 170° C. to 240° C. for 0.25 to 1.5 hours; one or more compounds (e) selected from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are added; following the addition of the one or more compounds (e), the reaction mixture is kept at a temperature in the range from 170° C. to 240° C. for 0.25 to 1.5 hours; and thereafter, the reaction mixture is cooled.

18. The process as claimed in claim 6, wherein a mixture comprising: (b) the one or more compounds selected from the group consisting of; polyether polyols having an average molar mass of 200 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4, and polyester polyols having an average molar mass of 250 g/mol to 8000 g/mol and a hydroxyl functionality of 2 to 4; (c) the one or more compounds selected from the group consisting of dicarboxylic anhydrides and dicarboxylic acids, and optionally one or more monocarboxylic acids; and (d) the water is initially charged and heated to a temperature of 130° C. to 230° C.; the polyurethane waste (a) is metered into this mixture such that the reaction mixture is formed, wherein the temperature is kept in the range from 130° C. to 230° C.; in parallel with the metering-in of the polyurethane waste (a), further water (d) is added in one or more portions, or continuously; one or more compounds (e) selected from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are added if the polyurethane waste (a) has been metered in at least to a third and has dissolved; or one or more compounds (e) selected from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms are added if the polyurethane waste (a) has completely dissolved; the reaction mixture is kept at a temperature in the range from 150° C. to 240° C. for 1 to 5 hours; a further portion of the one or more compounds (c) selected from the group consisting of dicarboxylic anhydrides and dicarboxylic acids is added; following the addition of the further portion of the one or more compounds (c), the reaction mixture is kept at a temperature in the range from 170° C. to 240° C. for 0.25 to 1.5 hours; a further portion of the one or more compounds (e) selected from the group consisting of diols having 2 to 8 carbon atoms and triols having 3 to 8 carbon atoms is added; following the addition of the further portion of the one or more compounds (e), the reaction mixture is kept at a temperature in the range from 170° C. to 240° C. for 0.25 to 1.5 hours; and thereafter, the reaction mixture is cooled.

Description

EXAMPLE 1

[0182] In a heatable stainless steel stirred reactor equipped with a fractionation column, under stirring, [0183] (b) 37 wt % of a long-chain polyether triol (Lupranol® 3300, BASF) having an average molar mass of 420 g/mol [0184] (c) 8 wt % of phthalic anhydride, and [0185] (d) 2 wt % of demineralized water
were initially charged and heated to 150° C. within 90 minutes. At this temperature, under stirring, [0186] (a) 40 wt % of polyurethane waste (post-consumer mattresses, unsorted, shredded to approximately 2 cm×2 cm×2 cm in size)
were added, with the temperature being kept in the range from 150° C. to 210° C. until the polyurethane waste (a) had dissolved. During the addition of the polyurethane waste (a), [0187] (d) a further 2 wt % of demineralized water
were added in steps. Thereafter, stirring was carried out for an hour, and subsequently [0188] (e) 7 wt % of short-chain glycol (diethylene glycol)
were added, with the temperature being kept in the range from 220° C. to 235° C. The mixture was then stirred for an hour at a temperature of 220° C. and subsequently, under stirring, [0189] (c) 2 wt % of maleic anhydride,
and, after 10 minutes, under stirring, [0190] (e) 2 wt % of dipropylene glycol
were added. The mixture was kept at 220° C. for a further 30 min and thereafter was cooled to 80° C., under stirring.

[0191] The polyol composition obtained was then pumped off, filtered using a self-cleaning filter (150 μm), and cooled to room temperature.

[0192] After filtration, the polyol composition has the following properties: [0193] Hydroxyl number: 268 mg KOH/g determined according to DIN 53240 [0194] Acid number: 0.7 mg KOH/g determined according to DIN 53402 [0195] Viscosity: 5600 m Pa*s at 25° C. determined according to DIN 53019 [0196] Amine number: 18 mg KOH/g determined according to DIN 53176.

[0197] This polyol composition is suitable for producing rigid polyurethane foam. The low acid number prevents a negative influence on catalysis in the subsequent production of rigid polyurethane foam.

EXAMPLE 2

[0198] In a heatable stainless steel stirred reactor equipped with a fractionation column, under stirring, [0199] (b) 38 wt % of a polyether triol (Dow Chemical Company, VORANOL CP 450) having an average molar mass of 440 g/mol [0200] (c) 7 wt % of phthalic anhydride, and 2 wt % of succinic anhydride, and [0201] (d) 1.5 wt % of demineralized water
were initially charged and heated to 165° C. within 100 minutes. At this temperature, under stirring, [0202] (a) 40 wt % of polyurethane waste (post-consumer mattresses, unsorted, shredded to approximately 2 cm×2 cm×2 cm in size)
were added, with the temperature being kept in the range from 165° C. to 200° C. until the polyurethane waste had dissolved. In parallel to the addition of the polyurethane waste (a), [0203] (d) a further 2.5 wt % of demineralized water
were added in steps. After the polyurethane waste (a) was completely metered into the reactor, under stirring, [0204] (e) 9 wt % of diethylene glycol
were added, with the temperature being kept in the range from 200° C. to 220° C. Alternatively, the diethylene glycol can be added when at least half, preferably at least two thirds of the polyurethane waste (a) has been metered into the reactor. The mixture was stirred in the range from 210° C. to 225° C. for 1.5 hours. Subsequently, under stirring, [0205] (c) 2 wt % of maleic anhydride
were added, and immediately thereafter the mixture was cooled to 120° C., under stirring.

[0206] The polyol composition obtained was then pumped off, filtered using a self-cleaning filter (150 μm), and cooled to room temperature.

[0207] A polyol composition was obtained having an acid number of less than 1.5 mg KOH/g and a content of primary aromatic amines of less than 0.05 wt %. After filtration, the polyol composition has the following properties: [0208] Hydroxyl number: 270 mg KOH/g determined according to DIN 53240 [0209] Acid number: 1.2 mg KOH/g determined according to DIN 53402 [0210] Viscosity: 4800 m Pa*s at 25° C. determined according to DIN 53019 [0211] Amine number: 14 mg KOH/g determined according to DIN 53176.

[0212] This polyol composition is suitable for producing rigid polyurethane foams (PUR and/or PUR/PIR). In experiments for producing PUR/PIR foam panels, use was made of polyol and primary polyol (i.e., polyol not obtained by cleavage of polyurethane) recovered from polyurethane waste by the process according to the invention, according to example 1 or 2, in a weight ratio of 10:90 to 50:50. PUR/PIR panels were obtained which had properties that were not adversely affected compared to the corresponding original PUR products (without addition of polyol recovered from polyurethane waste). In particular, the compressive strength, dimensional stability and thermal conductivity of the products were comparable or equivalent.

EXAMPLE 3

[0213] In a heatable stainless steel stirred reactor equipped with a fractionation column, under stirring, [0214] (b) 38 wt % of a long-chain polyether polyol (Arcola) Polyol 1108, Covestro) having a hydroxyl number of 48 mg KOH/g [0215] (c) 6 wt % of phthalic anhydride, and 4 wt % of acrylic acid [0216] (d) 1 wt % of demineralized water
were initially charged and heated to 160° C. within 90 minutes. At this temperature, under stirring, [0217] (a) 41 wt % of flexible polyurethane foam waste (unsorted)
were added, with the temperature being kept in the range from 160° C. to 210° C. In parallel to the addition of the polyurethane waste, [0218] (d) a further 4 wt % of demineralized water
were added in steps. Thereafter, stirring was carried out for an hour at 210° C. until the polyurethane waste had completely dissolved. Subsequently, the temperature was kept in the range from 220° C. to 225° C. for two hours, under stirring. The mixture was stirred for a further half hour at a temperature of 225° C. Then, under stirring, [0219] (c) 2 wt % of maleic anhydride
and, after 10 minutes, under stirring, [0220] (e) 1 wt % of dipropylene glycol
were added. The mixture was stirred at 220° C. for a further 30 min and thereafter was cooled to 130° C., under stirring, and [0221] (b) 3 wt. % of Arcola) Polyol 1108 were added.

[0222] The polyol composition obtained was filtered off at 100° C. by means of a 250 μm filter and cooled to room temperature.

[0223] After filtration, the polyol composition has the following properties: [0224] Hydroxyl number: 53 mg KOH/g determined according to DIN 53240 [0225] Acid number: 0.7 mg KOH/g determined according to DIN 53402 [0226] Viscosity: 8700 m Pa*s at 25° C. determined according to DIN 53019 [0227] Amine number: 9 mg KOH/g determined according to DIN 53176.

[0228] This polyol composition is suitable for producing flexible polyurethane foams.

EXAMPLE 4

[0229] In a heatable stainless steel stirred reactor equipped with a fractionation column, under stirring, [0230] (b) 36 wt % of a polyester polyol (Lupraphen 5608/1, BASF) having an average molar mass of 2000 g/mol, [0231] (c) 7 wt % of phthalic anhydride, and 3 wt % of adipic acid [0232] (d) 2 wt % of demineralized water
were initially charged and heated to 150° C. within 90 minutes. At this temperature, under stirring, [0233] (a) 41 wt. % of polyurethane waste (polyester-based shoe soles, unsorted)
were added, with the temperature being kept in the range from 150° C. to 210° C. In parallel to the addition of the polyurethane waste (a), a further [0234] (d) 1 wt % of demineralized water
were added in steps. Thereafter, stirring was carried out for an hour at 210° C. until the polyurethane waste (a) had completely dissolved. Subsequently, the temperature was kept in the range from 220° C. to 225° C. for two hours, under stirring. The mixture was stirred for a further half hour at a temperature of 225° C. Then, under stirring, [0235] (c) 1.5 wt % of hexahydrophthalic anhydride
and, after 10 minutes, under stirring, [0236] (e) 1.5 wt % of dipropylene glycol
were added. The mixture was kept at 220° C. for a further 30 min, under stirring, and thereafter was cooled to 130° C., under stirring, and [0237] (b) 7 wt. % of polyester polyol
were added.

[0238] The polyol composition obtained was filtered off at 100° C. by means of a 200 μm filter and cooled to room temperature.

[0239] After filtration, the polyol composition has the following properties: [0240] Hydroxyl number: 54 mg KOH/g determined according to DIN 53240 [0241] Acid number: 1.5 mg KOH/g determined according to DIN 53402 [0242] Viscosity: 4700 m Pa*s at 25° C. determined according to DIN 53019 [0243] Amine number: 5 mg KOH/g determined according to DIN 53176.

[0244] This polyol composition is suitable for producing polyester-based polyurethane shoe soles.

EXAMPLE 5

[0245] In a heatable stainless steel stirred reactor equipped with a fractionation column, under stirring, [0246] (b) 32 wt % of a polyester polyol (STEPANPOL® PS-3152) having an average molar mass of 350 g/mol, [0247] (c) 7 wt % of phthalic anhydride and 2 wt % of maleic anhydride [0248] (d) 2 wt % of demineralized water
were initially charged and heated to 150° C. within 90 minutes. At this temperature, under stirring, [0249] (a) 40 wt % of flexible polyurethane foam waste (unsorted)
were added, with the temperature being kept in the range from 150° C. to 210° C. In parallel to the addition of the polyurethane waste (a), [0250] (d) a further 1.5 wt % of demineralized water
and, in steps, [0251] (e) 14 wt % of diethylene glycol
were added, with the temperature being kept in the range from 180° C. to 210° C. Thereafter, stirring was carried out for an hour at 210° C. until the polyurethane waste had completely dissolved. Subsequently, the temperature was kept in the range from 220° C. to 235° C. for two hours, under stirring. The mixture was stirred for a further half hour at a temperature of 225° C. Then, under stirring, [0252] (c) 1.5 wt % of maleic anhydride
were added and stirred at 220° C. for a further 30 min and thereafter cooling was carried out to 100° C., under stirring.

[0253] The polyol composition obtained was filtered off at 100° C. by means of a 150 μm filter and cooled to room temperature.

[0254] After filtration, the polyol composition has the following properties: [0255] Hydroxyl number: 264 mg KOH/g determined according to DIN 53240 [0256] Acid number: 1.8 mg KOH/g determined according to DIN 53402 [0257] Viscosity: 7500 m Pa*s at 25° C. determined according to DIN 53019 [0258] Amine number: 16 mg KOH/g determined according to DIN 53176.

[0259] This polyol composition is suitable for producing rigid polyurethane foams (PUR and/or PUR/PIR).

EXAMPLE 6

[0260] In a heatable stainless steel stirred reactor equipped with a fractionation column, under stirring, [0261] (b) 38 wt % of a long-chain polyether polyol (VORANOL™ 8136, DOW Chemicals) having an average molar mass of 3100 g/mol and a hydroxyl number of 55 mg KOH/g [0262] (c) 7 wt % of phthalic anhydride, and 3 wt % of acrylic acid [0263] (d) 1 wt % of demineralized water
were initially charged and heated to 160° C. within 90 minutes. At this temperature, under stirring, [0264] (a) 41 wt % of flexible polyurethane foam waste (unsorted)
were added, with the temperature being kept in the range from 160° C. to 210° C. In parallel to the addition of the polyurethane waste (a), [0265] (d) a further 3.5 wt % of demineralized water
were added in steps. Thereafter, stirring was carried out for an hour at 210° C. until the polyurethane waste (a) had completely dissolved. Subsequently, the temperature was kept in the range from 220° C. to 225° C. for two hours, under stirring. The mixture was stirred for a further half hour at a temperature of 225° C. Then, under stirring, [0266] (c) 1.75 wt % of maleic anhydride
and, after 10 minutes, under stirring, [0267] (e) 1.75 wt % of dipropylene glycol
were added and the mixture was stirred at 220° C. for a further 30 min and thereafter cooled to 130° C., under stirring, and [0268] (b) 3 wt. % of VORANOL™ 8136, DOW Chemicals
were added.

[0269] The polyol composition obtained was filtered off at 100° C. by means of a 250 μm filter and cooled to room temperature.

[0270] After filtration, the polyol composition has the following properties: [0271] Hydroxyl number: 53 mg KOH/g determined according to DIN 53240 [0272] Acid number: 0.7 mg KOH/g determined according to DIN 53402 [0273] Viscosity: 8700 m Pa*s at 25° C. determined according to DIN 53019 [0274] Amine number: 9 mg KOH/g determined according to DIN 53176.

[0275] This polyol composition is suitable for producing flexible polyurethane foams.

EXAMPLE 7

[0276] In a heatable stainless steel stirred reactor equipped with a fractionation column, [0277] (b) 33 wt % of a long-chain polyether polyol (VORANOL™ 3322, DOW Chemicals) having a hydroxyl number of 48 mg KOH/g and an average molar mass of 3400 g/mol, together with [0278] (c) 9.5 wt % of phthalic anhydride, and 1 wt % of acrylic acid, and [0279] (d) 1.8 wt % of demineralized water
were initially charged and heated to 160° C. within 90 minutes. At this temperature, [0280] (a) 42 wt % of flexible polyurethane foam waste (unsorted)
were added, with the temperature being kept in the range from 160° C. to 210° C. In parallel to the addition of the polyurethane waste (a), [0281] (d) a further 1.5 wt % of demineralized water
were added in steps. Thereafter, stirring was continued for an hour at 210° C. until the polyurethane materials had completely dissolved. Subsequently, the temperature was kept in the range from 220° C. to 225° C. for two hours, under stirring. The mixture was stirred for a further half hour at a temperature of 225° C. Then, [0282] (c) 1 wt % of maleic anhydride
were added. The mixture was stirred at 220° C. for a further 30 min and thereafter was cooled to 130° C., under stirring, and [0283] (b) 10.2 wt. % of VORANOL™ 3322 were added.

[0284] The polyol composition obtained was filtered off at 100° C. by means of a 250 μm filter and cooled to room temperature.

[0285] After filtration, the polyol composition has the following properties: [0286] Hydroxyl number: 54 mg KOH/g determined according to DIN 53240 [0287] Acid number: 1.8 mg KOH/g determined according to DIN 53402 [0288] Viscosity: 8900 m Pa*s at 25° C. determined according to DIN 53019 [0289] Amine number: 10 mg KOH/g determined according to DIN 53176.

[0290] This polyol composition is suitable for producing flexible polyurethane foams.