DISPERSANT FOR PRODUCING POLYOL DISPERSIONS FROM POLYURETHANE WASTE AND USES THEREOF

FIELD OF THE INVENTION

The invention relates to polymers obtained by polymerization of ethylenically unsaturated acids or anhydrides onto mercapto-functionalized polyether polyols, to their use for producing polyol dispersions by acidolysis of polyurethane waste, as well as to the use of the resulting polyol dispersions for producing polyurethanes.

BACKGROUND

Very high quantities of polyurethane waste from the post-consumer sector (mattresses, automobile seats, sofas, cushions, upholstery, etc.) are disposed of every year. Further, during the processing of polyurethane block foams, polyurethane waste is also generated, which is sometimes disposed of.

It is therefore desirable to recycle these materials as far as possible and return them to the raw materials circuit in an ecological and economical process.

Chemical conversion of polyurethanes by means of water (hydrolysis), amines (aminolysis), alcohols (alcoholysis) and acids or anhydrides (acidolysis) have been proposed in order to convert polyurethanes into recycled polyols.

DE 19512778 C1 refers to the acidolysis of polyurethane waste with dicarboxylic acids or anhydrides. This document discloses the use of polyether polyols grafted with ethylenically unsaturated monomers containing carbonyl groups in order to obtain stable polyol dispersions.

DE 102013106364 A1 also discloses the acidolysis of polyurethane foams in the presence of grafted polyether polyols. The use of specific duplex steel is proposed in this document in order to produce a high quality recycled polyol.

WO2018/091568 A1 is directed to a method for the acidolysis of polyurethane waste, wherein the resulting polyols are subjected to a reaction with a short-chain diol or triol to increase their hydroxyl number and reduce their acid number.

Mercapto-functionalized polyether polyols grafted with ethylenically unsaturated monomers have been reported in the prior art (e.g. GB1031039, US4016332, EP0213701 , WO9637520). However, these polyols have not been disclosed as suitable dispersants or stabilizers for polyols resulting from the acidolysis of polyurethanes.

Despite the methods for preparing recycled polyols disclosed in the prior art, there is still room for improvement. In this regard, further effective methods for preparing polyol dispersions from waste polyurethanes are desirable.

BRIEF DESCRIPTION OF THE INVENTION

The authors of the present invention have found that polymers obtained by: (i) functionalizing some of the hydroxyl groups of a polyether polyol with a mercaptocontaining group to provide a mercapto-terminated polyol, and (ii) grafting an ethylenically unsaturated acid or anhydride onto the mercapto-terminated polyol, can be advantageously used as dispersants or stabilizers of the (recycled) polyols obtained by acidolysis of (waste) polyurethanes.

Indeed, these polymers have been found to provide polyol dispersions with improved particle size and/or viscosity compared to polyol dispersions obtained by acidolysis of polyurethanes using a polymer resulting from the direct grafting of an ethylenically unsaturated acid onto the polyether polyol (without prior functionalization with a mercapto group), as disclosed in the prior art. These polyol dispersions present a very good stability and particle size for their subsequent use as raw material in the preparation of polyurethanes.

In addition to the very good stability and particle size, the resulting polyol dispersions also have a suitable (low) viscosity for their subsequent use in the manufacture of new polyurethanes. In particular, said viscosity allows its subsequent handling, pumping and blending with the other components to prepare new polyurethanes. In contrast, when polyol dispersions with a very high viscosity are obtained, they do not have proper processability for their use in the industrial manufacture of polyurethanes. Additionally, since no further dilution of the polyol dispersion would be needed to achieve a viscosity suitable for its processability in the manufacture of polyurethanes, this would allow the incorporation of a higher amount of the recycled polyol in the new polyurethanes.

Further, the polymers of the invention have been found to be very effective dispersants for this type of polyols and so can be used in very low amounts in the acidolysis process. Consequently, they provide a very efficient and economical method for the recycling of high amounts of polyurethanes into stable polyol dispersions using a low amount of dispersant.

In particular, it has been found that stable polyol dispersions are obtained even when the polymer of the invention is used as dispersant in an amount of about 2 wt% based on the total mass of all constituents (starting materials) used in the acidolysis. In contrast, DE 19512778 C1 and WO 2018/091568 A1 disclose the use of the dispersants therein (non-mercapto functionalized before grafting) in an amount of more than 20 wt% based on the total mass of all constituents used in the acidolysis. This high amount of dispersant increases the cost of the process and also highly reduces the amount of polyurethane waste that can be recycled per reaction, which results in a less economical process.

Thus, in a first aspect the invention is directed to the use of the polymer of the invention as dispersant or stabilizer in the acidolysis of polyurethanes.

In a second aspect, the invention is directed to the use of the polymer of the invention for preparing polyol dispersions by acidolysis of polyurethanes.

The polymer of the invention is a polymer obtainable by a process comprising: i) reacting a polyether polyol having a hydroxyl functionality of 2-6 and a number average molecular weight of 300-15.000 Da, with a compound of formula (I)

O

R 1O— C " — R 2 ² — SH

(I) wherein

R ¹ is selected from H and a linear or branched C1-C10 alkyl group, and

R ² is a linear or branched C1-C10 alkylene group, in a molar ratio of the compound of formula (I) to the polyether polyol of from 0.05:1 to x:1 , wherein x is the hydroxyl functionality of the polyether polyol minus 1 , to provide a mercapto-functionalized polyether polyol; and ii) reacting the mercapto-functionalized polyether polyol with an ethylenically unsaturated acid or anhydride monomer in the presence of a radical initiator.

In a third aspect, the invention is directed to a process for producing a polyol dispersion from polyurethane, wherein the process comprises reacting the polyurethane with a dicarboxylic acid or anhydride in the presence of the polymer of the invention at a temperature of from 150°C to 250°C.

In a fourth aspect, the invention relates to a polyol dispersion obtainable by the process defined in the third aspect.

In a fifth aspect, the invention relates to the use of the polyol dispersion according to the fourth aspect, for the manufacture of polyurethanes.

In a sixth aspect, the invention relates to a process for preparing polyurethanes which comprises reacting the polyol dispersion according to the fourth aspect with a polyisocyanate. In a further aspect, the invention is directed to the polyurethane obtainable by the process of the seventh aspect.

In another aspect, the invention is directed to a polymer obtainable by a process comprising: i) reacting a polyether polyol having a hydroxyl functionality of 3-6 and a number average molecular weight of 3.000-15.000 Da, with a compound of formula (I)

O

R 1O— C " — R 2 ² — SH

(I) wherein

R ¹ is selected from H and a linear or branched C1-C10 alkyl group, and

R ² is a linear or branched C1-C10 alkylene group, in a molar ratio of the compound of formula (I) to the polyether polyol of from 0.05:1 to x:1 , wherein x is the hydroxyl functionality of the polyether polyol minus 1 , to provide a mercapto-functionalized polyether polyol; and ii) reacting the mercapto-functionalized polyether polyol with an ethylenically unsaturated acid or anhydride monomer in the presence of a radical initiator.

DETAILED DESCRIPTION OF THE INVENTION

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. As used herein, the singular forms “a” “an” and “the” include plural reference unless the context clearly dictates otherwise.

The terms "comprising", “comprise” and variations thereof, encompass the terms "consist(ing) essentially of” and "consist(ing) of". Thus, at each occurrence in the present application, the terms "comprising", “comprise” and variations thereof, may be replaced with the terms "consist(ing) essentially of” and "consist(ing) of".

When a range is indicated in the present document, both lower and upper limits are included in said range.

When the amount of a component is given by a range with a lower limit of 0 or 0.0, this means that said component might not be present or it might be present in an amount not higher than the specified upper limit of the range.

As used herein, the term "wt%" means weight-weight percent (w/w).

As used herein, the term "mol%" means mole-mole percent (mol/mol).

When the amount or ratio of a particular component is disclosed herein, said amount or ratio is based on the total amount of said component. For example, if a mixture of two or more ethylenically unsaturated acids or anhydrides are used, the amount or ratio of the ethylenically unsaturated acid or anhydride disclosed herein is based on the total amount of all the ethylenically unsaturated acids or anhydrides used.

The skilled person readily understands that, when a composition is defined by the weight percentage values of all the components it comprises, these values can never sum up to a value which is greater than 100%. The amount of all components that said composition comprises adds up to 100% of the weight of the composition.

For the purposes of the invention the expressions "obtainable", "obtained" and equivalent expressions are used interchangeably, and in any case, the expression "obtainable" encompasses the expression "obtained".

Unless specifically stated otherwise, or unless they are clearly incompatible, all the embodiments disclosed in relation to an aspect of the invention are also applicable to the other aspects. Also, any combination of the embodiments and preferences described herein is encompassed by the present invention unless otherwise indicated herein, or otherwise clearly contradicted by context.

It should be understood that the scope of the present disclosure includes all the possible combinations of embodiments disclosed herein, either belonging to the same aspect or to different aspects of the invention.

The polymer of the invention can be obtained by a process comprising: i) reacting a polyether polyol having a hydroxyl functionality of 2-6 and a number average molecular weight of 300-15.000 Da, with a compound of formula (I) wherein

R ¹ is selected from H and a linear or branched C1-C10 alkyl group, and

R ² is a linear or branched C1-C10 alkylene group, in a molar ratio compound of formula (l):polyether polyol from 0.05:1 to x:1 , wherein x is the hydroxyl functionality of the polyether polyol minus 1 ; and ii) reacting the resulting mercapto-functionalized polyether polyol with an ethylenically unsaturated acid or anhydride monomer in the presence of a radical initiator.

In an aspect, the invention is directed to a polymer of the invention that is obtained by a process comprising: i) reacting a polyether polyol having a hydroxyl functionality of 3-6 and a number average molecular weight of 3.000-15.000 Da, with a compound of formula (I) wherein

R ¹ is selected from H and a linear or branched C1-C10 alkyl group, and

R ² is a linear or branched C1-C10 alkylene group, in a molar ratio compound of formula (l):polyether polyol from 0.05:1 to x:1 , wherein x is the hydroxyl functionality of the polyether polyol minus 1 ; and ii) reacting the resulting mercapto-functionalized polyether polyol with an ethylenically unsaturated acid or anhydride monomer in the presence of a radical initiator.

The following embodiments in relation to the polymer of the invention apply to all aspects of the invention, unless specifically stated otherwise, or unless they are clearly incompatible.

The polyether polyol used to prepare the polymer of the invention is a polyol having ether groups within the polymer chain, also usually referred to as polyalkylene polyether polyol, having a hydroxyl functionality of 2-6 and a number average molecular weight of 300-15.000 Da.

In an embodiment, the polyether polyol is the product of polymerization of alkylene oxides having from 2 to 4 carbon atoms (e.g. ethylene oxide, propylene oxide, butylene oxide and mixtures thereof) in the presence of a starting compound having 2-6 active hydrogen atoms.

Suitable starting compounds for the obtention of the polyether polyol include, for example, polyhydroxyl compounds such as ethylene glycol, propylene glycol, 1 ,3- dihydroxypropane, 1 ,3-dihydroxybutane, 1 ,4-dihydroxybutane, 1 ,4-, 1 ,5-, 1 ,6- dihydroxyhexane, 1 ,2-, 1 ,3-, 1 ,4-, 1 ,6-, 1 ,8-di hydroxyoctane, 1 ,10-dihydroxydecane, 1 ,2,4-trihydroxybutane, 1 ,2,6-trihydroxyhexane, 1 ,1 ,1-trimethyl-olethane, 1 ,1 ,1- trimethylol propane, glycerol, sorbitol, pentaerythritol, xylitol, arabitol, mannitol, glucose, sucrose and the like. By alkoxylation of the starter, a suitable polyether polyol can be formed. The alkoxylation reaction may be catalysed using any conventional catalyst including, for example, potassium hydroxide or a double metal cyanide (DMC) catalyst.

Therefore, polyether polyols suitable to prepare the polymer of the invention include alkylene oxide adducts of ethylene glycol, propylene glycol, 1 ,3- dihydroxypropane, 1 ,3-dihydroxybutane, 1 ,4-dihydroxybutane, 1 ,4-, 1 ,5-, 1 ,6- dihydroxyhexane, 1 ,2-, 1 ,3-, 1 ,4-, 1 ,6-, 1 ,8-di hydroxyoctane, 1 ,10-dihydroxydecane, 1 ,2,4-trihydroxybutane, 1 ,2,6-trihydroxyhexane, 1 ,1 ,1-trimethyl-olethane, 1 ,1 ,1- trimethylol propane, glycerol, sorbitol, pentaerythritol, xylitol, arabitol, mannitol, glucose, sucrose and the like; particularly adducts of alkylene oxides having from 2 to 4 carbon atoms.

According to an embodiment, when the polyether polyol is the product of polymerization of two or more, such as two or three, alkylene oxides, the alkylene oxides may be added simultaneously or sequentially so that the polyether polyol has internal blocks, terminal blocks or a random distribution of different oxyalkylene groups.

Examples of suitable polyether polyols include polyoxyethylene diols, triols, tetrols, pentols and hexols; polyoxypropylene diols, triols, tetrols, pentols and hexols; and mixtures thereof.

When ethylene oxide and propylene oxide mixtures are used to produce the polyether polyol, the ethylene oxide and propylene oxide may be added simultaneously or sequentially so that the polyether polyol has internal blocks, terminal blocks or a random distribution of oxyethylene groups and/or oxypropylene groups.

In an embodiment, the polyether polyol is built up of propylene oxide units, ethylene oxide units, or mixtures thereof. That is, the polymeric part of the polyether polyol (i.e. excluding the starting compound) consists only of propylene oxide units, ethylene oxide units, or mixtures thereof. Therefore, it is a poly(ethylene oxide and/or propylene oxide).

In a further embodiment, the polyether polyol is built up of propylene oxide and ethylene oxide units; that is, it is a propylene oxide-ethylene oxide copolymer. In an embodiment, the polyether polyol is a random or blocked propylene oxide-ethylene oxide copolymer with or without ethylene oxide terminal (cap) groups.

In another embodiment, the polyether polyol is a propylene oxide polymer with ethylene oxide terminal groups.

Therefore, the polyether polyol may be a propylene oxide homopolymer or an ethylene oxide homopolymer or a random or blocked propylene oxide-ethylene oxide copolymer with or without ethylene oxide terminal groups.

In a particular embodiment, the polyether polyol is a poly(ethylene oxide and/or propylene oxide) adduct of a polyhydric alcohol, particularly a polyhydric alcohol selected from ethylene glycol, propylene glycol, 1 ,3-dihydroxypropane, 1 ,3-dihydroxybutane, 1 ,4- dihydroxybutane, 1 ,4-, 1 ,5-, 1 ,6-dihydroxyhexane, 1 ,2-, 1 ,3-, 1 ,4-, 1 ,6-, 1 ,8- di hydroxyoctant, 1 ,10-dihydroxydecane, glycerol, sorbitol, 1 ,1 ,1 -trimethylol propane, 1 ,2,4-trihydroxybutane, 1 ,2,6-trihydroxyhexane, 1 ,1 ,1 -trimethyl-olethane, pentaerythritol, xylitol, arabitol, mannitol, glucose and sucrose; more particularly, from glycerol and sorbitol.

In an embodiment, the polyether polyol is built up of propylene oxide monomers and 0-95 wt%, or even 0-75 wt%, of ethylene oxide monomers based on the weight of the monomers (propylene oxide+ethylene oxide monomers). In an embodiment, the polyether polyol is built up of propylene oxide and 0-50 wt%, or even 0-30 wt%, of ethylene oxide based on the weight of the monomers (propylene oxide+ethylene oxide monomers). In an embodiment, the polyether is a propylene oxide homopolymer, i.e. it is built up of propylene oxide units or monomers.

In another embodiment, the polyether polyol is built up of ethylene oxide monomers and 0-95 wt%, or even 0-75 wt%, of propylene oxide monomers based on the weight of the monomers (propylene oxide+ethylene oxide monomers). In another embodiment, the polyether polyol is built up of ethylene oxide and 0-50 wt%, or even 0-30 wt%, of propylene oxide based on the weight of the monomers (propylene oxide+ethylene oxide monomers). In an embodiment, the polyether polyol is an ethylene oxide homopolymer, i.e. it is built up of ethylene oxide units or monomers.

In an embodiment, the polyether polyol is built up of propylene oxide and ethylene oxide and comprises 5-95 wt% of propylene oxide monomers and 5-95 wt% of ethylene oxide monomers, based on the weight of the monomers (propylene oxide+ethylene oxide monomers). In an embodiment, the polyether polyol is built up of propylene oxide and ethylene oxide and comprises 5-50 wt%, or even 8-30 wt%, of ethylene oxide, based on the weight of the monomers (propylene oxide+ethylene oxide monomers). In a particular embodiment, the polyether polyol is a propylene oxide polymer comprising 5-50 wt%, or even 8-30 wt%, of polyethylene oxide terminal groups, based on the weight of the monomers (propylene oxide+ethylene oxide monomers). In a further embodiment, the polyether polyol is propylene oxide adduct of glycerol or sorbitol comprising 5-50 wt%, or even 8-30 wt%, of polyethylene oxide terminal groups, based on the weight of the monomers (propylene oxide+ethylene oxide monomers). In some embodiments, the content of ethylene oxide in the poly(ethylene oxide and propylene oxide) polymer is IQ- 25 wt% based on the weight of the monomers. The ethylene oxide and propylene oxide content can be determined, for example, by ¹³ C-NMR.

The polyether polyol may have hydroxyl functionality of 2, 3, 4, 5 or 6. In an embodiment, it has a functionality of 3 to 6, for example a functionality of 3 or 6. In a particular embodiment, it has a functionality of 3. In another embodiment, it has a functionality of 6.

According to an embodiment, the polyether polyol has a molecular weight from 1.000 to 15.000 Da, or even from 2.000 to 15.000 Da. In an embodiment, it has a molecular weight from 3.000 to 14.000 Da., or even from 4.000 to 13.000 Da.

In further embodiments, the polyether polyol has a hydroxyl number in the range from 15 to 100 mgKOH/g, or even from 20 to 60 mgKOH/g.

In accordance with particular embodiments, the polyether polyol has a viscosity from 200 to 8.000 mPa s. In further embodiments, is has a viscosity from 400 to 5.000 mPa s, or even from 500 to 2.000 mPa s.

In a particular embodiment, the polyether polyol has hydroxyl functionality of 3-6 and a molecular weight from 2.000 to 15.000 Da.

According to an embodiment, the polyether polyol is a poly(ethylene oxide and/or propylene oxide) polymer having a hydroxyl functionality of 3-6.

In a further embodiment, the polyether polyol is a poly(ethylene oxide and/or propylene oxide) polymer having a hydroxyl functionality of 3-6 and a molecular weight from 3.000 to 15.000 Da.

In a particular embodiment, the polyether polyol is a poly(ethylene oxide and/or propylene oxide) adduct of a polyhydric alcohol selected from glycerol, sorbitol, 1 ,1 ,1- trimethylol propane, 1 ,2,4-trihydroxybutane, 1 ,2,6-trihydroxyhexane, 1 ,1 , 1 -trimethyl- olethane, pentaerythritol, xylitol, arabitol, mannitol, glucose and sucrose, having a hydroxyl number from 15 to 100 mgKOH/g.

In the compound of formula (I), R ² is a linear or branched alkylene group, i.e. a linear or branched saturated divalent hydrocarbon chain having from 1 to 10 carbon atoms. The term hydrocarbon chain refers to a chain radical consisting of hydrogen and carbon atoms. In a particular embodiment, R ² is a Ci-Ce linear or branched alkylene group. In a further embodiment, R ² is a C1-C4 linear or branched alkylene group, such as methylene, ethylene, propylene or butylene groups.

In an embodiment, R ¹ is selected from H and a linear or branched Ci-Ce alkyl group, or from H and a linear or branched C1-C4 alkyl, such as methyl, ethyl, propyl or butyl groups.

In a particular embodiment, the compound of formula (I) is selected from 2- mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, 2- mercaptobutiric acid, 3-mercaptobutiric acid, 4-mercaptobutiric acid, 2-mercapto-4- methyl-valeric acid, 2-mercaptopentanoic acid, 3-mercaptopentanoic acid, 5- mercaptopentanoic acid, 6-mercaptohexanoic acid, 7-mercaptoheptanoic acid, 8- mercaptooctanoic acid, 9-mercaptononanoic acid, 10-mercaptodecanoic acid, 3- mercapto-2-(mercaptomethyl)propionic acid and the C1-C10 alkyl, preferably Ci-Ce alkyl, esters thereof, such as methyl, ethyl or propyl 2-mercaptoacetate, methyl, ethyl or propyl 2-mercaptopropionate, methyl, ethyl or propyl 3-mercaptopropionate, methyl, ethyl or propyl 2-mercaptobutiroate, methyl, ethyl or propyl 3-mercaptobutiroate, methyl, ethyl or propyl 4-mercaptobutiroate, and mixtures thereof.

According to an embodiment, the compound of formula (I) is selected from 2- mercaptoacetic acid, 2-mercaptopropionic acid and 3-mercaptopropionic acid. In a particular embodiment, the compound of formula (I) is 2-mercaptoacetic acid. In another embodiment, the compound of formula (I) is 3-mercaptopropionic acid.

It is particularly suitable that the mercapto-functionalized polyether polyol obtained after step i) maintains one or more non-functionalized hydroxyl (-OH) groups, on average. Accordingly, the molar ratio of the compound of formula (I) to the polyether polyol in step i) is from 0.05:1 to x:1 , wherein x is the hydroxyl functionality of the polyether polyol minus 1 (f-1).

In a particular embodiment, the molar ratio of the compound of formula (I) to the polyether polyol in step i) is from 0.1 :1 to x:1 , or even from 0.5:1 to x:1. In a further embodiment, it is from 0.8: 1 to x: 1 , wherein x is the hydroxyl functionality of the polyether polyol minus 1. In another embodiment, said ratio is from 1 :1 to x:1.

In a particular embodiment, x is the hydroxyl functionality of the polyether polyol minus 1.5.

According to an embodiment, the molar ratio of compound of formula (I) to polyether polyol in step i) is 0.05-4:1 , or even 0.1 -3:1 (provided that it is equal or lower than x:1 , x being the hydroxyl functionality of the polyether polyol minus 1). In a further embodiment, said molar ratio is 0.5-3:1 , or even 0.8-3: 1 (provided that it is equal or lower than x:1 , x being the hydroxyl functionality of the polyether polyol minus 1). In another embodiment, said ratio is from 1 :1 to 3:1.

According to an embodiment, the molar ratio of compound of formula (I) to polyether polyol in step i) is 0.05-2:1 , or even 0.1 -2:1 (provided that it is equal or lower than x:1 , x being the hydroxyl functionality of the polyether polyol minus 1). In a further embodiment, said molar ratio is 0.5-1.8:1 , or even 0.8-1.5:1 (provided that it is equal or lower than x:1 , x being the hydroxyl functionality of the polyether polyol minus 1).

In a particular embodiment, when the polyether polyol has a functionality of 2, the molar ratio compound of formula (l):polyether polyol is 0.05-1 :1. In a further embodiment, it is 0.05-0.8:1 , or even 0.1-0.8:1. In another embodiment, it is 0.5-1 :1 , or even 0.5-0.8:1.

In a particular embodiment, when the polyether polyol has a functionality of 3, the molar ratio compound of formula (l):polyether polyol is 0.05-2:1 or 0.1-2:1. In a further embodiment, it is 0.05-1.5:1 , or even 0.05-1.3:1. In an embodiment, it is 0.1-1.5:1 , or even 0.1-1.3:1. In another embodiment, it is 0.5-2:1 , or even 0.5-1.5:1. According to a particular embodiment, said ratio is 0.8-1.5:1.

In a particular embodiment, when the polyether polyol has a functionality of 4, the molar ratio compound of formula (l):polyether polyol is 0.05-3:1 or 0.1-3:1. In a further embodiment, it is 0.05-2.5:1 , or even 0.05-2:1. In an embodiment, it is 0.1 -2.5:1 , or even 0.1-2:1. In another embodiment, it is 0.5-3: 1 , or even 0.5-2.5:1. According to a particular embodiment, said ratio is 0.8-2.5:1.

In a particular embodiment, when the polyether polyol has a functionality of 5, the molar ratio compound of formula (l):polyether polyol is 0.05-4:1 or 0.1-4:1. In a further embodiment, it is 0.05-3:1 , or even 0.05-2:1. In an embodiment, it is 0.1 -3:1 , or even 0.1- 2:1. In another embodiment, it is 0.5-4: 1 , or even 0.5-3: 1. According to a particular embodiment, said ratio is 0.8-3: 1.

In a particular embodiment, when the polyether polyol has a functionality of 6, the molar ratio compound of formula (l):polyether polyol is 0.05-5:1 or 0.1-5:1. In a further embodiment, it is 0.05-4:1 , or even 0.05-3:1. In an embodiment, it is 0.1-4:1 , or even 0.1- 3:1. In another embodiment, it is 0.05-2:1. In another embodiment, it is 0.5-5:1 , or even 0.5-3: 1. According to a particular embodiment, said ratio is 0.8-3:1.

In a particular embodiment, when the polyether polyol has a functionality of 6, the molar ratio compound of formula (l):polyether polyol is 1-5:1. In a further embodiment, it is 1.5-4:1 , or even 2-4:1. In another embodiment, it is 1-4:1 , or even 1-3:1.

The reaction between the polyether polyol and the compound of formula (I) in step i) may be performed by means known in the art. In an embodiment, step i) is performed in the presence of a catalyst, in order to accelerate the esterification reaction between the hydroxyl group in the polyether polyol and the carboxylic acid or ester group in the compound of formula (I), for example in an amount from 0.5 to 30 mol%, or even 1 to 10 mol%, with respect to the polyether polyol.

Suitable esterification catalysts include sulfuric acid, p-toluenesulfonic acid, methanesulphonic acid, phosphoric acid, tin oxides (such as di(n-butyl)tin oxide, n- butyltin hydroxide oxide), phosphorous oxides, tin alkanoates (such as tin bis-octanoate, tin bis-(2-ethylhexanoate), butyl tin tris-(2-ethylhexanoate), tin tetraoctanoate, tin tetra- (2-ethylhexanoate)), tetra alkyl titanates (such as tetra-(n-butyl) titanate, tetra- (isopropyl). In an embodiment, the catalyst is an acid catalyst, such as sulfuric acid or p- toluenesulfonic acid. In a particular embodiment, step i) is performed in the presence of sulfuric acid, preferably concentrated sulfuric acid, as catalyst.

Step i) may be performed at a temperature from 50°C to 200°C, such as 100- 150°C.

Reaction of the polyether polyol with the compound of formula (I) in step i) may be carried out for 0.5 to 24 hours, or even for 2 to 24 hours. In a particular embodiment, step i) is carried out for 3 to 15 hours, or even for 5 to 10 hours.

The reaction in step i) may be performed in the presence of a solvent or diluent, such as mono-ols (i.e., monohydroxy alcohols), polyols, hydrocarbons, ethers, and mixtures thereof. In a particular embodiment, said reaction is performed without addition of a solvent or diluent.

The reaction in step i) might be performed under vacuum in order to remove the subproducts of the reaction (e.g. water). In another embodiment, the reaction in step i) may be performed under azeotropic distillation conditions, e.g. in the presence of toluene, so that the water generated in the reaction is removed by azeotropic distillation with toluene.

After step i), a mercapto-functionalized (or mercapto-terminated) polyether polyol is obtained. In accordance with particular embodiments, the mercapto-functionalized polyether polyol has a viscosity from 500 to 8.000 mPa s. In further embodiments, it has a viscosity from 500 to 5.000 mPa s, or even from 500 to 3.000 mPa s.

In a particular embodiment, the mercapto-functionalized polyether polyol contains, on average, from 0.05 to 4.0 moles of mercapto groups per mole of mercapto- functionalized polyether polyol (provided that said value is equal to or lower than x, wherein x is the hydroxyl functionality of the starting polyether polyol minus 1); that is, the starting polyether polyol is reacted with from 0.05 to 4.0 moles of the compound of formula (I). In an embodiment, it contains, on average, 0.1-3.0, or even 0.5-3.0, moles of mercapto groups per mole of mercapto-functionalized polyether polyol (provided that said value is equal to or lower than x, wherein x is the hydroxyl functionality of the starting polyether polyol minus 1).

The amount of mercapto groups in relation to the mercapto-functionalized polyether polyol, means the average mercapto groups and refers to the moles of mercapto groups (by reaction with a compound of formula (I)) per mole of said polyether polyol. Therefore, said amount of mercapto groups corresponds basically to the moles of the compound of formula (I) with respect to the moles of polyether polyol. The mercapto-functionalized polyether polyol obtained in step i) is subsequently reacted with an ethylenically unsaturated acid or anhydride monomer (also referred herein as ethylenically unsaturated acid or anhydride) in the presence of a free-radical initiator, and optionally in the presence of a diluent and/or of other ethylenically unsaturated monomers different from the ethylenically unsaturated acid or anhydride monomer. Suitable ethylenically unsaturated acids or anhydrides include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, angelic acid, tiglic acid, citraconic acid, 2,3-dimethylmaleic acid, 3-butenoic acid, itaconic acid, maleic anhydride, citraconic anhydride, 2,3-dimethylmaleic anhydride, and mixtures thereof.

In a particular embodiment, the ethylenically unsaturated acid or anhydride is selected from acrylic acid, methacrylic acid and mixtures thereof. In a further embodiment, the ethylenically unsaturated acid is acrylic acid.

In an embodiment, the molar ratio of the ethylenically unsaturated acid or anhydride to the mercapto-functionalized polyether polyol in step ii) is from 3:1 to 30:1. In a particular embodiment, the molar ratio ethylenically unsaturated acid or anhydride:mercapto-functionalized polyether polyol in step ii) is from 4:1 to 20:1 or even from 5:1 to 15:1.

According to an embodiment, the weight ratio of the ethylenically unsaturated acid or anhydride to the mercapto-functionalized polyether polyol in step ii) is from 0.01 :1 to 0.3:1. In a particular embodiment, the weight ratio ethylenically unsaturated acid or anhydride:mercapto-functionalized polyether polyol in step ii) is from 0.02:1 to 0.3:1 or even from 0.03:1 to 0.2:1.

Preferably, the molar ratio of the ethylenically unsaturated acid or anhydride in step ii) to the compound of formula (I) in step i) is equal to or higher than 2. In an embodiment, the molar ratio of the ethylenically unsaturated acid or anhydride in step ii) to the compound of formula (I) in step i) is from 2:1 to 30:1 , or even from 3:1 to 30:1. In a particular embodiment, said molar ratio is from 3:1 to 20:1 or even from 4:1 to 15:1.

In addition to the ethylenically unsaturated acid or anhydride monomer, other ethylenically unsaturated monomers might be present in step ii). These other ethylenically unsaturated monomers will also polymerize, along with the ethylenically unsaturated acid or anhydride, in the presence of the radical initiator.

The other ethylenically unsaturated monomers might be present in step ii) in an amount equal to or lower than 85 wt%, or equal to or lower than 70 wt%, based on the total weight of the ethylenically unsaturated monomers present in step ii) (i.e. the total weight of the ethylenically unsaturated acid or anhydride monomers + the other ethylenically unsaturated monomers). In an embodiment, they might be present in an amount equal to or lower than 50 wt%, or equal to or lower than 40 wt%, based on the total weight of the ethylenically unsaturated monomers present in step ii). Therefore, in a particular embodiment, step ii) comprises 0-85 wt%, or even 0-70 wt%, of other ethylenically unsaturated monomers, based on the total weight of the ethylenically unsaturated monomers present in step ii). In a further embodiment, step ii) comprises 0- 50 wt%, or even 0-40 wt%, of other ethylenically unsaturated monomers, based on the total weight of the ethylenically unsaturated monomers present in step ii).

In step ii), the molar ratio of other ethylenically unsaturated monomers to the ethylenically unsaturated acid or anhydride might be equal to or lower than 3:1 , or even equal to or lower than 1 :1. In an embodiment, the molar ratio of other ethylenically unsaturated monomers to the ethylenically unsaturated acid or anhydride might be equal to or lower than 0.5:1 , or even equal to or lower than 0.4:1. In a particular embodiment, step ii) comprises 0-75 mol%, or even 0-50 mol%, of other ethylenically unsaturated monomers, based on the total moles of ethylenically unsaturated monomers present in step ii). In a further embodiment, step ii) comprises 0-40 mol%, or even 0-30 mol%, of other ethylenically unsaturated monomers based on the total moles of the ethylenically unsaturated monomers present in step ii).

In a particular embodiment, the only ethylenically unsaturated monomer present in step ii) is the ethylenically unsaturated acid or anhydride. That is, no other ethylenically unsaturated monomers different from the ethylenically unsaturated acid or anhydride are added.

The term “ethylenically unsaturated” as used herein refers to a monomer containing an ethylenic unsaturation (>C=C<, i.e. two double bonded carbon atoms) that is capable to undergoing free radically induced addition polymerization reactions.

The other ethylenically unsaturated monomers might be selected from styrene, a- methylstyrene, butylstyrene, chlorostyrene, cyanostyrene, bromostyrene, methyl acrylate, methyl methacrylate, ethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl acrylate, butyl acrylate, isopropylmethacrylate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N,N-dimethyl acrylamide, N- (dimethylaminomethyl)acrylamide, vinyl acetate, and mixtures thereof. In an embodiment, the other ethylenically unsaturated monomer is styrene.

In a particular embodiment, step ii) comprises reacting the mercapto-functionalized polyether polyol obtained in step i) with an ethylenically unsaturated monomer in the presence of a radical initiator, wherein 15-100 wt% of the ethylenically unsaturated monomer, or even 30-100 wt% of the ethylenically unsaturated monomer, is an ethylenically unsaturated acid or anhydride. In a particular embodiment, 50-100 wt% of the ethylenically unsaturated monomer, or even 60-100 wt% of the ethylenically unsaturated monomer, is an ethylenically unsaturated acid or anhydride.

In a particular embodiment, step ii) comprises reacting the mercapto-functionalized polyether polyol obtained in step i) with an ethylenically unsaturated monomer in the presence of a radical initiator, wherein 15-100 mol% of the ethylenically unsaturated monomer, or even 30-100 mol% of the ethylenically unsaturated monomer, is an ethylenically unsaturated acid or anhydride. In a particular embodiment, 50-100 mol% of the ethylenically unsaturated monomer, or even 60-100 mol% of the ethylenically unsaturated monomer, is an ethylenically unsaturated acid or anhydride.

The molar ratio of the total ethylenically unsaturated monomers (ethylenically unsaturated acid or anhydride + other ethylenically unsaturated monomers, if any) to the mercapto-functionalized polyether polyol in step ii) might be from 4:1 to 50:1. In a particular embodiment, the molar ratio total ethylenically unsaturated monomers:mercapto-functionalized polyether polyol in step ii) is from 4:1 to 30:1 or even from 5:1 to 20:1.

Step ii) might be optionally performed in the presence of a diluent. In a particular embodiment, step ii) is performed without addition of a diluent.

Suitable diluents include mono-ols (i.e., monohydroxy alcohols), polyols, hydrocarbons, ethers, and mixtures thereof. Preferably, the diluent in step ii) is a polyol.

Suitable polyols for use as diluents in step ii) include polyols having a hydroxyl functionality from 2 to 8; or even from 2 to 6. In a particular embodiment, the polyol has a molecular weight from 300 Da to 15.000 Da, or from 1.000 to 12.000 Da. In an embodiment, is has a molecular weight from 2.000 to 6.000 Da. In a further embodiment, the polyol has a hydroxyl number in the range from 10 to 400, or from 15 to 150, or even from 15 to 100 mg KOH/g.

In an embodiment, the polyol used as diluent in step ii) is a polyol having a hydroxyl functionality from 2 to 6, a molecular weight from 300 to 15.000 Da, and a hydroxyl number from 15 to 150 mg KOH/g.

In an embodiment, the polyol is selected from a polyether polyol, a polyester polyol and a polycarbonate polyol, that is, a polyol as defined above having ether groups, ester groups or carbonate groups, respectively, within the polymer chain.

In a preferred embodiment, the polyol is a polyether polyol also usually referred to as polyalkylene polyether polyol. In a preferred embodiment, said polyether polyol is the product of polymerization of alkylene oxides having from 2 to 4 carbon atoms (e.g. ethylene oxide, propylene oxide, butylene oxide and mixtures thereof) in the presence of a starting compound having at least one active hydrogen atom, preferably from 2 to 6.

Suitable starting compounds for the obtention of polyether polyol that might be used as diluent in step ii) include, for example, polyhydroxyl compounds such as, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, tripropylene glycol, 1 ,3-dihydroxypropane, 1 ,3-dihydroxybutane, 1 ,4-dihydroxybutane, 1 ,4-, 1 ,5-, 1 ,6- dihydroxyhexane, 1 ,2-, 1 ,3-, 1 ,4-, 1 ,6-, 1 ,8-di hydroxyoctane, 1 ,10-dihydroxydecane, 1 ,2,4-trihydroxybutane, 1 ,2,6-trihydroxyhexane, 1 ,1 ,1-trimethyl-olethane, 1 ,1 ,1- trimethylol propane, glycerol, sorbitol, pentaerythritol, xylitol, arabitol, mannitol, glucose, sucrose and the like; water; ammonia; amino alcohols such as ethanolamine, diethanolamine, triethanolamine; and primary and/or secondary amine or polyamines such as ethylenediamine, aniline and toluene diamine. By alkoxylation of the starter, a suitable polyether polyol can be formed. The alkoxylation reaction may be catalysed using any conventional catalyst including, for example, potassium hydroxide or a double metal cyanide (DMC) catalyst.

In an embodiment, the polyether polyol that might be used as diluent in step ii) is built up of propylene oxide units, ethylene oxide units, or mixtures thereof. That is, it is a poly(ethylene oxide and/or propylene oxide).

In a further embodiment, the polyether polyol that might be used as diluent in step ii) is built up of propylene oxide and ethylene oxide units; that is, it is a propylene oxideethylene oxide copolymer. In an embodiment, said polyether polyol is a random or blocked propylene oxide-ethylene oxide copolymer with or without ethylene oxide terminal (cap) groups.

Therefore, the polyether polyol that might be used as diluent in step ii) may be a propylene oxide homopolymer or an ethylene oxide homopolymer or a random or blocked propylene oxide-ethylene oxide copolymer with or without ethylene oxide terminal groups.

In an embodiment, the polyether polyol that might be used as diluent in step ii) is built up of propylene oxide monomers and 0-95 wt%, or even 0-75 wt%, of ethylene oxide monomers based on the weight of the monomers (propylene oxide+ethylene oxide monomers). In an embodiment, said polyether polyol is built up of propylene oxide and 0-50 wt%, or even 0-30 wt%, of ethylene oxide based on the weight of the monomers (propylene oxide+ethylene oxide monomers). In an embodiment, said polyether is a propylene oxide homopolymer. In an embodiment, the polyether polyol that might be used as diluent in step ii) is built up of ethylene oxide monomers and 0-95 wt%, or even 0-75 wt%, of propylene oxide monomers based on the weight of the monomers (propylene oxide+ethylene oxide monomers). In another embodiment, said polyether polyol is built up of ethylene oxide and 0-50 wt%, or even 0-30 wt%, of propylene oxide based on the weight of the monomers (propylene oxide+ethylene oxide monomers). In an embodiment, said polyether polyol is an ethylene oxide homopolymer.

In another embodiment, the polyether polyol that might be used as diluent in step ii) is built up of propylene oxide and ethylene oxide and comprises 2-98 wt% of propylene oxide monomers and 2-98 wt% of ethylene oxide monomers, based on the weight of the monomers (propylene oxide+ethylene oxide monomers. In an embodiment, the polyether polyol that might be used as diluent in step ii) is built up of propylene oxide and ethylene oxide and comprises 2-50 wt%, or even 5-30 wt% of ethylene oxide based on the weight of the monomers (propylene oxide + ethylene oxide monomers).

The polyether polyol used as diluent in step ii) may have hydroxyl functionality of 2, 3, 4, 5, 6, 7 or 8. In an embodiment, it has a functionality of 3 to 6. In a particular embodiment, it has a functionality of 2 to 5, or even of 2-4. In another embodiment, it has a functionality of 3.

In a particular embodiment, the polyether polyol that might be used as diluent in step ii) is a poly(ethylene oxide and/or propylene oxide) having a hydroxyl functionality from 2 to 6, and a molecular weight from 300 to 15.000 Da.

The polyether polyol that might be used as diluent in step ii) might be the same as or different from the polyether polyol used in step i) to prepare the mercaptofunctionalized polyether polyol.

If a polyol is used as diluent in step ii), said step is performed in a mixture of polyols (the polyol and the mercapto-functionalized polyether polyol). It is preferred that the polyol that might be used as diluent in step ii) has not been subjected to any reaction or treatment to induce mercapto functionalization. In that case, the mixture of polyols in step ii) will have a level of amount of mercapto groups lower than that of the mercaptofunctionalized polyether polyol obtained in step i).

In a particular embodiment, step ii) is optionally performed in the presence of a polyol as diluent and the mixture of polyols in step ii) (polyol if any + mercaptofunctionalized polyether polyol) has, on average, an amount of less than 4 moles, or even less than 3 moles, of mercapto groups per mole of total polyols (i.e. the mixture of polyols present in step ii)), provided that said value is equal to or lower than x, wherein x is the hydroxyl functionality of the starting polyether polyol minus 1. In a particular embodiment, the mixture of polyols in step ii) has, on average, an amount of mercapto groups from 0.05 to 4.0, or even from 0.05 to 3.0 mole per mole of total polyols present in step ii), provided that said value is equal to or lower than x, wherein x is the hydroxyl functionality of the starting polyether polyol minus 1. In an embodiment, it contains, on average, 0.1-3.0, or even 0.5-3.0, moles of mercapto groups per mole of polyols present in step ii), provided that said value is equal to or lower than x, wherein x is the hydroxyl functionality of the starting polyether polyol minus 1 .

In a particular embodiment, the mercapto-functionalized polyether polyol that is reacted in step ii) contains from 0.05 to 4.0, or even from 0.05 to 3.0 moles of mercapto groups per mole of total polyols present in step ii) (i.e. mercapto-functionalized polyether polyol + other polyols present in step ii), if any, such as the optional diluent) provided that said value is equal to or lower than x, wherein x is the hydroxyl functionality of the starting polyether polyol minus 1. In another embodiment, it contains 0.1-3.0, or even 0.5-3.0, moles of mercapto groups per total moles of polyols present in step ii). In a further embodiment, it contains 0.8-3.0 moles of mercapto groups per total moles of polyols present in step ii), provided that said value is equal to or lower than x, wherein x is the hydroxyl functionality of the starting polyether polyol minus 1 .

According to an embodiment, the diluent might be present in step ii) in an amount of 0 to 400 wt% with respect to the weight of the mercapto-functionalized polyether polyol. In an embodiment, it is present in an amount of 5 to 400 wt% with respect to the weight of the mercapto-functionalized polyether polyol. In a further embodiment, the diluent may be present in step ii) in an amount of 0 to 300 wt% with respect to the weight of the mercapto-functionalized polyether polyol, or even from 0 to 250 wt%.

Step ii) is performed in the presence of a radical initiator. The term “radical initiator” or “free-radical initiator” refers to a compound that generates a radical when energy (e.g. from light or heat) is imparted to the compound. This radical initiator might generate a thiyl radical by reacting with the mercapto-functionalized polyether polyol. This thiyl radical might also induce a reaction with the carbon-carbon double bonds in the ethylenically unsaturated acid or anhydride (or the other ethylenically monomers, if present), thus leading to the polymerization of the ethylenically unsaturated acid or anhydride (and the other ethylenically monomers, if present) with itself.

Suitable radical initiators for step ii) include conventional free-radical initiators which are known in the art, such as thermal initiators and photoinitiators. Suitable free- radical initiators include thermal initiators such as alkyl and aryl peroxides, alkyl and aryl hydroperoxides, acyl peroxides, peroxyesters, persulfates, perborates, percarbonates and azo compounds. Some specific examples include hydrogen peroxide, dibenzoyl peroxide, didecanoyl peroxide, dilauroyl peroxide, t-butyl hydroperoxide, benzoyl peroxide, di-t-butyl peroxide, di(3,5,5-trimethylhexanoyl)peroxide, diisobutyryl peroxide, t-butylperoxy diethyl acetate, t-butyl peroctoate, t-butyl peroxy isobutyrate, t-butyl peroxy 3,5,5-trimethyl hexanoate, t-butyl perbenzoate, t-butyl peroxy pivalate, t-butyl peroxy-2- ethyl hexanoate, tert-amyl peroxy-2-ethylhexanoate, 1 ,1 ,3,3-tetramethylbutyl peroxy-2- ethyl hexanoate, cumene hydroperoxide, azobis(isobutyronitrile) and 2,2’-azo bis-(2- methylbutyronitrile). Suitable photoinitiators include benzoin ethers, benzils, a-hydroxyl- or a-alkoxy- or a-aminoalkylphenones, acylphenyl oxides, thioxanthones and benzophenones. Some specific examples include benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-propyl ether, benzoin isobutyl ether, benzoin n-butyl ether, benzoin, benzil, acetophenone, 2,2-diethoxyacetophenone, 4'- hydroxyacetophenone, p-dimethylaminoacetophenone, benzophenone, 2- chlorobenzophenone, 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, diphenyl(2,4,6-trimethyl-benzoyl)phosphine oxide, thioxanthen-9-one, 2- chlorothioxanthen-9-one, 4-(dimethylamino)benzophenone, and 4,4'- dihydroxybenzophenone.

In an embodiment, initiators include acyl peroxides such as didecanoyl peroxide, lauroyl peroxide, diisobutyryl peroxide and di(3,5,5-trimethylhexanoyl)peroxide, peroxyesters such as tert-amyl peroxy-2-ethyl hexanoate, 1 ,1 ,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, hydroperoxides such as cumene hydroperoxide, and azo compounds such as azobis(isobutyronitrile) and 2,2’-azo bis-(2-methylbutyronitrile).

In an embodiment, the molar ratio of the radical initiator to the mercaptofunctionalized polyether polyol in step ii) is from 0.005:1 to 0.5:1. In a particular embodiment, the molar ratio of radical initiatormercapto-functionalized polyether polyol in step ii) is from 0.005:1 to 0.2:1 , or even from 0.005:1 to 0.1 :1. In an embodiment, said ratio is 0.01-0.2:1 , or even 0.01-0.1 :1.

In a particular embodiment, the amount of the radical initiator used in step ii) is from 0.01 to 3 wt%, or from 0.05 to 2 wt%, with respect to the weight of the mercaptofunctionalized polyether polyol. In another embodiment, the amount of the radical initiator in step ii) is from 0.01 to 0.3 wt%, or from 0.03 to 0.25 wt%, with respect to the weight of the mercapto-functionalized polyether polyol.

In an embodiment, the mercapto-functionalized polyether polyol is present in step ii) in an amount of 20-98 wt%, or even 50-98 wt%, with respect to the total weight of all the components in step ii). In a particular embodiment, the mercapto-functionalized polyether polyol is present in step ii) in an amount of 80-98 wt% based on the total weight of all the components in step ii), or even 85-98 wt%.

In an embodiment, the diluent might be present in step ii) in an amount of 0-80 wt%, or even 0-50 wt%, with respect to the total weight of all the components in step ii). In a particular embodiment, the diluent might be present in step ii) in an amount of 0-20 wt%, based on the total weight of all the components in step ii), or even 0-10 wt%.

In an embodiment, the ethylenically unsaturated acid or anhydride is present in step ii) in an amount of 2-30 wt%, or even 2-20 wt%, with respect to the total weight of all the components in step ii). In a particular embodiment, the ethylenically unsaturated acid or anhydride is present in step ii) in an amount of 2-15 wt%, or 3-20 wt%, based on the total weight of all the components in step ii). In a further embodiment, it is 3-15 wt%.

In an embodiment, the other ethylenically unsaturated monomer different from the ethylenically unsaturated acid or anhydride is present in step ii) in an amount of 0-30 wt%, or even 0-20 wt%, with respect to the total weight of all the components in step ii). In a particular embodiment, the other ethylenically unsaturated monomer different from the ethylenically unsaturated acid or anhydride is present in step ii) in an amount of 0-15 wt%, or even 0-10 wt%, based on the total weight of all the components in step ii).

In an embodiment, the total ethylenically unsaturated monomers (ethylenically unsaturated acid or anhydride + other ethylenically unsaturated monomers, if any) are present in step ii) in an amount of 2-60 wt%, or even 3-60 wt%, with respect to the total weight of all the components in step ii). In a particular embodiment, the total amount of ethylenically unsaturated monomers in step ii) is of 2-40 wt%, or even 3-25 wt%, based on the total weight of all the components in step ii). In a further embodiment, it is 3-20 wt%, or even 3-15 wt%.

In an embodiment, the radical initiator is present in step ii) in an amount of 0.01-5 wt%, or even 0.03-1 wt%, with respect to the total weight of all the components in step ii). In another embodiment, the radical initiator is present in step ii) in an amount of 0.01- 0.2 wt%, with respect to the total weight of all the components in step ii).

In an embodiment, step ii) comprises reacting 50-98 wt% of mercaptofunctionalized polyether polyol, 0-50 wt% of diluent, 2-30 wt% of ethylenically unsaturated acid or anhydride, 0.01-5 wt% of radical initiator, and 0-30 wt% of other ethylenically unsaturated monomers different from the ethylenically unsaturated acid or anhydride with respect to the total weight of all the components in step ii).

According to an embodiment, step ii) comprises reacting 80-98 wt% of mercapto- functionalized polyether polyol, 0-20 wt% of diluent, 2-30 wt% of ethylenically unsaturated acid or anhydride, 0.01-5 wt% of radical initiator, and 0-15 wt% of other ethylenically unsaturated monomers different from the ethylenically unsaturated acid or anhydride, with respect to the total weight of all the components in step ii).

If a thermal radical initiator is used, the temperature at which step ii) takes place should be selected to allow the thermal decomposition of the free-radical initiator leading to free-radicals that enable initiating the polymerization reactions. In a particular embodiment, step ii) is carried out at a temperature from 25°C to 200°C, such as 60- 160°C, or even 60-150°C.

Reaction in step ii) may be carried out for 0.5 to 24 hours, or even for 2 to 24 hours. In a particular embodiment, step ii) is carried out for 2 to 15 hours, or even for 4 to 10 hours.

Step ii) (polymerization reaction) may be carried out in several ways, including batch, semi-batch and continuous processes.

After step ii), the polymer of the invention is obtained.

In accordance with particular embodiments, the polymer of the invention has a molecular weight from 600 to 18.000 Da. In an embodiment, it has a molecular weight from 3.200 to 18.000 Da., or even from 4.500 to 16.000 Da.

In some particular embodiments, the polymer of the invention has an acid number in the range from 20 to 150 mgKOH/g. In an embodiment, it has an acid number from 20 to 100 mgKOH/g, or even from 25 to 80 mgKOH/g.

In accordance with particular embodiments, the polymer of the invention has a viscosity from 5.00 to 250.000 mPa s. In further embodiments, it has a viscosity from 5.000 to 210.000 mPa s, or even from 10.000 to 150.000 mPa s.

The polymer of the invention has been found to be useful as dispersant of the polyols obtained by acidolysis of polyurethanes. The term “acidolysis” refers to the treatment of polyurethanes, preferably (waste) polyurethane foams, with a carboxylic acid or carboxylic acid derivative, e.g. anhydride, to convert the polyurethanes into (recycled) polyols by chemical degradation.

The terms “dispersant” and “stabilizer” are used interchangeably herein. These terms generally refer to an agent that is added to a medium to prevent coalescence or settling of the particles contained therein and/or to provide a uniform dispersion.

Therefore, in another aspect, the invention is directed to the use of the polymer of the invention as dispersant in the acidolysis of polyurethanes.

In another aspect, the invention is directed to the use of the polymer of the invention for preparing polyol dispersions by acidolysis of polyurethanes.

In a further aspect, the invention refers to a process for producing polyol dispersions from polyurethane, wherein the process comprises reacting the polyurethane with a dicarboxylic acid or anhydride in the presence of a polymer according to the present invention at a temperature of from 150°C to 250°C (acidolysis process).

In an embodiment, the polyurethane in the acidolysis of the invention is a polyurethane foam.

Preferably the polyurethane or polyurethane material used as raw material in the acidolysis is polyurethane waste, including flexible, semi-rigid and rigid (such as PUR foam and PIR foam) polyurethane waste, such as flexible, semi-rigid and rigid polyurethane waste foams.

A non-limiting exemplary definition for the term polyurethane refers to a polymer containing urethane groups resulting from the reaction of a polyol with an isocyanate. In an embodiment, these polymers might be obtained from formulations having an isocyanate index from 70 to 550. In the context of the invention, the term polyurethane is also intended to include polyisocianurates (PIR). The term polyisocianurates is intended to denote polymers resulting from the reaction of polyols with isocyanates that contain, in addition to urethane functional groups, other types of functional groups, in particular triisocyanuric rings formed by trimerization of isocyanates. Polyisocyanurates are typically obtained from formulations exhibiting an isocyanate index number from 180 to 550. In an embodiment, the polyurethane used in the present invention is a polymer obtained from a formulation having an isocyanate index from 70 to 140, or from 80 to 120. In a further embodiment, it is a polymer obtained from a formulation having an isocyanate index from 90 to 110. The isocyanate index is defined as the ratio of isocyanate-groups over isocyanate-reactive hydrogen atoms present in a polyurethane formulation. Thus, the isocyanate index expresses the percentage of isocyanate actually used in a formulation with respect to the amount of isocyanate theoretically required for reacting with the amount of isocyanate-reactive hydrogen used in a formulation.

Flexible polyurethane foams are polyurethanes which have an open cell structure and a hardness of from 30 to 900 N at 40% loading measured in accordance with EN ISO 2439:2008 (E).

Semi-rigid polyurethane foams are polyurethanes which have an open cell structure but have a compressive strength of at least 100 kPa measured in accordance with EN ISO 844:2009. Rigid polyurethane foams are polyurethanes which, in the region of the polyurethane, have a closed cell structure and a compressive strength of at least 100 kPa measured in accordance with EN ISO 844:2009. In the context of the present invention, the term rigid polyurethane foam shall also encompass rigid polyisocyanurate foam.

For the purposes of the present invention, polyurethane waste includes waste from the post-consumer, in particular, polyurethane materials which are envisaged for disposal by the end consumer. These materials preferably comprise polyurethane foam, high-resilience polyurethane foam, polyurethane viscoelastic foam and/or other polyurethane foams. Preferred polyurethane waste is waste originating from cushions, upholstery and mattresses.

Optionally, the polyurethane waste can be polyurethane mixed with other polymers and/or fillers, for example those based on polyether or polyester, as well as polyureas and their copolymers are suitable for the acidolysis process according to the invention. The invention is also suitable for polyurethanes that are associated with thermoplastic polymers, such as polyolefins, ABS or PVC. Such thermoplastics can be filtered out from the recycled polyol after the acidolysis reaction.

However, it is preferred to use polyurethane waste that is free of textiles, metal, wood and other foreign materials. It is also preferred that the polyurethane waste is in comminuted form.

In a particular embodiment, the polyurethane waste is sorted to separate the polyurethane from other foreign materials (e.g. other polymers different from polyurethanes) and/or comminuted before the acidolysis.

Suitable dicarboxylic acids or anhydrides for the acidolysis include succinic acid, glutaric acid, maleic acid, malic acid, phthalic acid, adipic acid, succinic anhydride, glutaric anhydride, maleic anhydride, malic anhydride, phthalic anhydride, adipic anhydride and mixtures thereof.

The dicarboxylic acid or anhydride might be used in a total amount of from 3 to 50 wt%, or even from 5 to 40 wt%, based on the total mass of all the starting materials or components in the acidolysis (i.e. total mass of the acidolysis reaction). The starting materials or components in the acidolysis of the invention include the polyurethane, the polymer of the invention, the dicarboxylic acid or anhydride and any other optional components present in the reaction mixture.

In an embodiment, the dicarboxylic acid or anhydride is used in the acidolysis in an amount of from 3 to 50 wt%, or even from 5 to 40 wt%, based on the sum of the mass of the polyurethane, the polymer of the invention and the dicarboxylic acid or anhydride.

In an embodiment, the weight ratio of dicarboxylic acid or anhydride to polyurethane in the acidolysis is from 0.05: 1 to 1 : 1 , or even from 0.1 :1 to 0.5: 1.

The polymer of the invention might be used in an amount of from 0.5 to 40 wt%, or even from 1.0 to 40 wt%, based on the total mass of all the starting materials or components in the acidolysis. In a particular embodiment, the polymer of the invention might be used in an amount of from 1.5 to 40 wt%, or even from 1.5 to 20 wt%, based on the total mass of the starting materials or components in the acidolysis. In a particular embodiment, the polymer of the invention might be used in an amount of from 2 to 40 wt%, or from 2 to 20 wt%, or even from 2 to 10 wt%, based on the total mass of the starting materials or components in the acidolysis.

In an embodiment, the polymer of the invention is used in the acidolysis in an amount of from 0.5 to 40 wt%, or even from 1 .0 to 40 wt%, based on the sum of the mass of the polyurethane, the polymer of the invention and the dicarboxylic acid or anhydride. In a particular embodiment, the polymer of the invention is used in an amount of from 1.5 to 40 wt%, or from 2 to 40 wt%, or even from 2 to 20 wt%, based on the sum of the mass of the polyurethane, the polymer of the invention and the dicarboxylic acid or anhydride.

In an embodiment, the weight ratio of the polymer of the invention to polyurethane in the acidolysis is 0.02-0.25: 1 , or even 0.2-0.15:1.

The polyurethane might be used in an amount of from 45 to 95 wt%, or even from 50 to 90 wt%, based on the total mass of all the starting materials or components in the acidolysis. The polyurethane might be used in an amount of from 50 to 85 wt%, or even from 50 to 80 wt%, based on the total mass of all the starting materials or components in the acidolysis.

In an embodiment, the polyurethane is used in the acidolysis in an amount of from 45 to 95 wt%, or even from 50 to 90 wt%, based on the sum of the mass of the polyurethane, the polymer of the invention and the dicarboxylic acid or anhydride. In an embodiment, the polyurethane is used in the acidolysis in an amount of from 50 to 85 wt%, or even from 50 to 80 wt%, based on the sum of the mass of the polyurethane, the polymer of the invention and the dicarboxylic acid or anhydride.

Optionally, the acidolysis might be performed in the presence of other additional components, such as a diluent. Suitable diluents include those mentioned herein in relation to the optional diluent in step ii) of the process for preparing the polymer of the invention. In a particular embodiment, said diluent is a polyol selected from those disclosed above in relation to the diluent in step ii) of the process for preparing the polymer of the invention. The optional diluent in the acidolysis might be the same or different from the optional diluent in step ii) of the process for preparing the polymer of the invention.

In a particular embodiment, a diluent might be used in the acidolysis in an amount of 0-20 wt%, or even 0-10 wt%, based on the total mass of all the starting materials or components in the acidolysis.

The polyurethane used in the acidolysis may include other components typically present in polyurethanes, such as fillers, surfactants, flame retardants, catalysts, and/or colorants (pigments or dyes), for example calcium carbonate, styrene-acrylonitrile copolymers, triethylenediamine, N,N- dimethylethanolamine, dibutyltin dilaurate, tin octoate, melamine, polysiloxane-polyoxyalkylene block copolymers, ureas, and/or imides.

The acidolysis might be carried out at a temperature of from 150 to 250°C. According to a particular embodiment, the acidolysis might be performed at a temperature of from 170 to 250°C, or even from 170 to 220°C.

Acidolysis may be carried out for 1 to 24 hours, or from 1 to 8 hours, or even for 2 to 6 hours

In some embodiments of the invention, the acidolysis is performed in a reactor or vessel made of stainless steel. In further embodiments, all the apparatus and equipment that come into contact with the starting materials or reactants of the acidolysis (e.g. containers, stirrers, reactors) are made of stainless steel.

The acidolysis according to the present invention can be carried out in a batch, semi-batch or continuous process.

After acidolysis, the polyol dispersion of the invention is obtained.

In accordance with particular embodiments, the polyol dispersion of the invention has a hydroxyl number in the range from 5 to 650 mgKOH/g. In a particular embodiment, when the polyurethane used in the acidolysis is a flexible polyurethane foam, the resulting polyol dispersion has a hydroxyl number in the range from 20 to 50 mgKOH/g.

In some particular embodiments, the polyol dispersion of the invention has an acid number in the range from 5 to 20 mgKOH/g. In an embodiment, it has an acid number from 5 to 15 mgKOH/g.

In accordance with particular embodiments, the polyol dispersion of the invention has a viscosity from 5.000 to 30.000 mPa s. In further embodiments, it has a viscosity from 5.000 to 25.000 mPa s. In accordance with particular embodiments, the polyol dispersion of the invention has a particle size D50 equal to or lower than 50 pm. In an embodiment, the polyol dispersion of the invention has a particle size D50 equal to or lower than 20 pm, or even equal to or lower than 10 pm. In further embodiments, it has a particle size D50 from 0.5 to 20 pm, or even 0.5 to 10 pm. In an embodiment, it has a particle size D50 from 0.8 to 10 pm.

The polyol dispersion of the invention can be directly used in the manufacture of polyurethanes or it can be reacted or mixed with other components in order to adjust its properties (e.g., hydroxyl number, acid number and/or viscosity) before it is used in the manufacture of polyurethanes.

For example, it can be reacted with a diol or triol as disclosed in WO 2018/091568 A1 , in order to increase its OH number and/or reduce its acid number, before being used in the manufacture of polyurethanes.

Alternatively or additionally, it can be mixed with a polyether poyol (different from the polyol dispersion of the invention), e.g. in order to reduce its viscosity, before being used in the manufacture of polyurethanes. Suitable polyether polyols include those disclosed hereinabove in relation to the preparation of the polymer of the invention.

The polyol dispersion obtained after the acidolysis is an isocyanate-reactive polyol dispersion and can therefore be used in the manufacture of polyurethanes.

Accordingly, in another aspect the invention refers to the use of the polyol dispersion of the invention for producing polyurethanes.

In a further aspect, the invention is directed to a process for preparing polyurethanes which comprises reacting the polyol dispersion of the invention with a polyisocyanate. In another aspect, the invention is directed to the polyurethanes obtainable by said process (denoted herein as final polyurethanes).

According to an embodiment, the final polyurethane is a polyurethane foam, including flexible, semi-rigid and rigid polyurethane foams.

Conventional additives for the preparation of polyurethanes, amounts thereof and reaction conditions will vary depending on the type and desired properties of the polyurethane to be prepared. The skilled person knows different reagents, additives and conditions necessary to prepare the polyurethane.

The process for preparing polyurethanes comprises reacting the polyol dispersion of the invention with a polyisocyanate, optionally in the presence of further additives for the preparation of polyurethanes, such as additional polyols, chain transfer agents, catalysts, stabilizers, blowing agents, flame retardants, fillers and/or pigments. Suitable methods for the preparation of polyurethanes are well known in the art.

Suitable polyisocyanates include aromatic, aliphatic, cycloaliphatic polyisocyanates and combinations thereof. Representative of these types are diisocyanates such as m-phenylene diisocyanate, toluene-2,4- and 2,6-diisocyanates, mixtures of 2,4- and 2,6-hexamethylene-1 ,6-diisocyanate, tetramethylene- 1 ,4- diisocyanate, cyclo-hexane-1 ,4-diisocyanate, hexahydrotolylene diisocyanate (and isomers), naphthylene-1 ,5-diisocyanate, 1-methoxy-phenyl-2,4-diisocyanate, diphenylmethane-4,4'-, 2,4’ and 2,2’-diisocyanates, 4,4'-biphenylene diisocyanate, 3,3'- dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate, and 3,3'- dimethyldiphenylmethane-4,4'-diisocyanate; triisocyanates such as 4, 4', 4'- triphenylmethane triisocyanate, polymethylene polyphenylisocyanate and tolylene 2,4,6- triisocyanate; and tetraisocyanates such as 4,4'-dimethyldiphenylmethane-2,2',5,5'- tetraisocyanate, and mixtures thereof. Especially useful are 4,4'-, 2,4' and 2,2'-isomers of diphenylmethane diisocyante (MDI), toluene-2,4- and 2,6-diisocyanates (TDI), and mixtures thereof.

In an embodiment, the polyisocyanate is used in the preparation of polyurethane at an isocyanate index of from 60 to 140, or from 80 to 120, or even from 90 to 110.

Suitable blowing agents are known in the art, such as the carbon dioxide generated by the decarboxylation of the carbamic acid generated by the reaction of water with the isocyanate, liquid carbon dioxide, methylene chloride, HCFC or pentane.

Suitable catalysts include aminic compounds, such as triethylenediamine, N- methylmorpholine, N,N-dimethylcyclohexylamine, pentamethyldiethylenetriamine, tetramethylethylenediamine, bis(dimethylaminoethyl)ether, 1 -methyl-4- dimethylaminoethyl-piperazine, 3-methoxy-N- dimethylpropylamine, N-ethylmorpholine, dimethylethanolamine, N-cocomorpholine, N,N-dimethyl-N',N'-dimethyl isopropylpropylenediamine, N,N-diethyl-3-diethylaminopropylamine and dimethylbenzylamine; and metal catalyst based on tin, zinc or bismuth such as tin octoate, tin dibutyldilaurate or zinc octoate.

Additional additives that may be employed in preparing the polyurethane include fillers (e.g., talc, silica, titania, magnesia, calcium carbonate, carbon black, graphite, magnesium silicate or clays such as kaolinite and montmorillinite); flame retardants (e.g., halogenated flame retardants, such as hexabromocyclododecane and brominated polymers, or phosphorus flame retardants such as triphenylphosphate, dimethyl methylphosphonate, red phosphorus or aluminium diethyl phosphinate); acid scavengers (e.g., calcium stearate, magnesium oxide, zinc oxide, tetrasodium pyrophosphate or hydrotalcite); antioxidants (e.g., sterically hindered phenols, phosphites and mixtures thereof); surfactans (e.g. silicon surfactants) and pigments.

Unless otherwise specified, the term “molecular weight” as used herein refers to the number average molecular weight. The number average molecular weight is determined by gel permeation chromatography. Preferably, molecular weight means the number average molecular weight as measured by gel permeation chromatography using polyethylene glycol as standard.

Viscosities disclosed therein are determined at 25°C. The viscosity is determined according to EN ISO 3219 at 25°C and 25 s-1. Viscosity measurements (in mPa.s) can be obtained employing a Haake iQ viscotester rheometer using the spindle CC25DIN/Ti.

By the term “hydroxyl functionality” or “functionality” it should be understood the average number of hydroxyl groups per molecule of polyol, which is theoretically equal to the number of hydroxyl groups of the initiator molecule used in the polyol synthesis. As used herein, term “hydroxyl functionality” or “functionality” in relation to the polyol refers to the functionality of the initiator used for its preparation.

As used herein, the hydroxyl number is defined as the number of milligrams of potassium hydroxide required for the complete hydrolysis of the fully phthalylated derivative prepared from 1 gram of polyol. The hydroxyl number can be determined according to ASTM -E1899.

The hydroxyl number can also be defined by the equation:

OH = (56.1x1000xf)/mol. wt. wherein:

OH: represents the hydroxyl number of the polyol, f: represents the functionality of the polyol, and mol. wt. represents the molecular weight of the polyol.

The acid number is defined as the number of milligrams of potassium hydroxide required for the complete neutralization of the sample and can be determined in accordance with ASTM D1662. It can be measured by titration of the polyol with KOH in a mixture of isopropyl alcohol and water (62.5/37.5 wt/wt).

The particle size D50 (or Dx(50)) means the median diameter (50% volume of the particles present a particle size within the specified value of D50). It can be determined by laser diffraction; for example, using a Mastersizer 3000 spectometer dispersing the sample in ethanol and calculating the particle size distribution using Fraunhofer theory. The invention is illustrated by means of the following examples, which in no case limit the scope of the invention.

EXAMPLES

Methods

Hydroxyl number, acid number, molecular weight, viscosity and particle size D50 values disclosed in the following examples were determined according to the standards or methods mentioned above.

Materials

Polyol A: A sorbitol (functionality 6) initiated polyether polyol (PO/EO) with a molecular weight of 11.410 Da, a hydroxyl number of 29.5 mgKOH/g, a content of polyethylene oxide terminal blocks of 16.2 wt %, based on the total weight of the ethylene oxide and propylene oxide monomers (i.e. OE/(OE+OP), without considering the weight of the starter), and a viscosity at 25° C of 1500 mPa s

Polyol B: A glycerol (functionality 3) initiated polyether polyol (PO/EO) with a molecular weight of 4.800 Da, a hydroxyl mumber of 35 mg KOH/g, and a content of polyethylene oxide terminal blocks of 18 wt%, based on the total weight of the ethylene oxide and propylene oxide monomers, and a viscosity at 25 °C of 870 mPa s

Sulfuric acid (98 %) was purchased from sigma Aldrich.

Mecaptoacetic acid (98 %) was purchased form Sigma Aldrich.

Acrylic acid (98 %) was purchased form Acros Organics.

Cumyl Hydroperoxide (80 %) (CHP) was purchased from Acros Organics.

Trigonox 421 was purchased form Nuryon.

Alcupol® F4811 is a polyol from Repsol. It is glycerol propoxylated with 12% ethylene oxide; with 3500 molecular weight and 48 mgKOH/g hydroxyl number.

Tegoamin®BDE and Tegoamin®33 are amine catalysts purchased from Evonik. Kosmos®29 is a stannous octoate-based metal catalyst purchased from Evonik. Tegostab®B 8255 is a silicone based surfactant purchased from Evonik.

TDI T80/20 is a mixture of the two isomeric forms 2,4-toluene diisocyanate and 2,6-toluene diisocyanate in a ratio 80:20, purchased from Covestro (Desmodur® T80). i-functionalized

The polyol, the compound of formula (I), and concentrated sulfuric acid were loaded in a 1 L glass reactor equipped with stirring, jacket and connection to a vacuum pump. The temperature was raised up to 120 °C and kept at that temperature for 7 h. Vacuum (150 mbar) was applied during the entire process to remove water from the system.

The particulars of each example and the properties of the resulting products are shown in the following table.

Examples 4-8: General process for the polymerization (grafting) reaction

A 250 mL glass reactor equipped with mechanical stirring, heating jacket and a condenser, was loaded with the mercapto-functionalized polyol and acrylic acid. Nitrogen was bubbled into the mixture for 5 min in order to remove the oxygen, and then the radical initiator was added into the system. The temperature was raised to 90 °C under nitrogen and kept for 8 h.

The particulars of each example and the properties of the resulting products are shown in the following table. Examples 9-16: General process for the acidolysis of polyurethane foam

Polyurethane foam acidolysis was performed following the procedure described in DE 19512778 C1. Basically, an electrically heated and temperature-controlled threenecked glass reactor equipped with a stirrer was used for the process. Initially the dispersant was introduced in the reactor. Then the temperature was raised to 200°C, and water blown toluene diisocyanate (TDI) flexible polyurethane foam waste and the dicarboxylic acid were added over the dispersant. The mixture was stirred for 2-6 hours at 200°C and then cooled while stirring.

The particulars of each example and the properties of the resulting products are shown in the following table. The indicated wt% are based on the total mass of the components added into the reactor.

All the resulting recycled polyols had finely dispersed particles and were stable against sedimentation at room temperature for at least 1 month. No gels were found in the recycled polyol.

Comparative example 1 (use of non-grafted mercapto-functionalized polyol as dispersant)

Polyurethane foam acidolysis was performed following the same procedure as described above for examples 9-16 and using 8.62 wt% of the mercapto-functionalized polyol prepared in example 1 as dispersant.

The recycled polyol thus obtained had a very high viscosity that could not be even measured. The particle size Dx(50) was 386 pm and solid particles precipitated in less than 24 h.

Comparative examples 2-5 (use of grafted non-functionalized polyol as dispersant) In comparative examples 2-5 a polyol according to DE 19512778 C1 and WO 2018/091568 A1 was used as dispersant in the acidolysis of polyurethane foam. That is a polyether polyol that was directly reacted with an ethylenically unsaturated monomer in the presence of a radical initiator, without the prior functionalization of the polyether polyol with a mercapto group.

These dispersants, obtained by grafting acrylic acid directly onto the polyether polyol (Polyol B), were used in the acidolysis reaction under the same conditions as in examples 9-16 above according to the invention.

The particulars of each example are shown in the following table. The indicated wt% are based on the total mass of the components added into the reactor.

In comparative examples 2 and 4, the dispersant was used in an amount similar to that disclosed for this same type of dispersants in DE 19512778 C1 and WO 2018/091568 A1 , i.e. about 30 wt%. In comparative example 3 and 5, the dispersant was used in an amount similar to that used in the examples according to the invention above.

The properties of the resulting recycled polyols were as follows:

- Comparative example 2: the viscosity of the recycled polyol was very high and could not be even measured, which makes it unsuitable for its direct use in the manufacture of polyurethanes. Further, the recycled polyol also contained gels, which make it unsuitable for the manufacture of polyurethanes.

- Comparative example 3: the recycled polyol contained gels, which make it unsuitable for the manufacture of polyurethanes.

- Comparative example 4: the recycled polyol had a very high viscosity (81430 mPa s), which makes it unsuitable for its direct use in the manufacture of polyurethanes.

- Comparative example 5: the recycled polyol had a big particle size D50 (23.9 pm), which denotes that the polyol dispersion is not stable. Indeed, solid particles precipitated in less than 5 days.

This comparative examples prove that non-mercapto functionalized grafted polyols, as those disclosed in DE 19512778 C1 and WO 2018/091568 A1 , are less efficient as dispersants in the acidolysis of polyurethanes and cannot be used in an amount as low as those according to the present invention. Further, when used in higher amounts, they provide polyol dispersions with a very high viscosity, which might prevent their (direct) use in the industrial production of polyurethanes.

Examples 17-20 and Comparative Examples 6-9: General process for the preparation of polyurethane foams

Recycled polyols of the present invention (Ex. 9, Ex. 11 , Ex.12 and Ex.15) and recycled polyols of the present invention (comparative Ex. 2-5) were used as starting material for the preparation of polyurethane foams. The reagents used for the preparation of the foams and their amounts expressed in parts per hundred parts of polyol (pphp) are detailed in the table below.

The following process was followed to prepare the polyurethane foams. The polyols, water, amine catalysts (TegoaminOBDE and Tegoamin® 33), stannous octoate catalyst (Kosmos®29) and silicone surfactant (Tegostab® B8255) were added in relation to 500 g of polyol in a 1 liter container. The contents were mixed at 2.000 rpm for 60 seconds with an agitator. The mixture thus obtained was then degassed for 10 seconds. While the mixer was still rotating, the amount needed of toluene diisocyanate was added to the container and the content was mixed at 2.000 rpm for 10 seconds. The mixture was then poured into a 25x25 cm square box test, where the foam rose until the reaction was complete. The foam was then heated in an oven at 150°C for 30 minutes. Subsequently, the foam was allowed to cure for 24 hours at room temperature before proceeding to its evaluation.

¹⁾ 10% tolerance for density value can be accepted.

²⁾ Compression stress is a measure of the load-bearing properties of the foam and defines the application in which the foam can be used. In seating or beading applications, the first determining parameter for optimal comfort is foam hardness. If the foam is too hard (i.e. higher compression stress), it may restrict flow in the capillary blood vessels under the skin and induce discomfort.

³⁾ Highly resilience foams (i.e. higher resilience values) are targeted at high quality furniture and bedding applications, which need improved durability and comfort characteristics.

⁴⁾ Higher compression set values compared to the target indicate worse recovery of the foam with use.

⁵⁾ Higher porosity values mean better breathability, which is more desired in flexible polyurethane foams.

As shown in the table above, the flexible polyurethane foams obtained by substituting 6 parts of Alcupol® F4811 with the polyols from comparative examples 2-5 (see polyurethane foams in comparative examples 6-9) have worse porosity, compression set75% values, resilience and compression stress values than those obtained by substituting 6 parts of Polyol Alcupol@ F4811 with the polyols of the present invention (see polyurethane foams in examples 17-20). The recycled polyols of the invention provide polyurethane foams with very good properties, comparable to the target values with only Alcupol® F4811 as polyol source.