A method of recovering raw materials from rigid polyurethane

Abstract

There is provided a method of recovering raw materials from a rigid polyurethane product, the method comprising: performing a glyco-hydrolysis reaction on a rigid polyurethane product to form a single-phase product mixture comprising a first polyol component and a polyamine component, wherein a glycolysis agent, water and the rigid polyurethane are reactants in the glyco-hydrolysis reaction, wherein the first polyol component comprises a polyol compound having an OH value of at least 250 KOH / g and an average hydroxyl functionality of at least 3, wherein the rigid polyurethane product is the reaction product of a second polyol component and an isocyanate component, the second polyol component comprising a polyol compound having an OH value of at least 250 KOH / g and an average hydroxyl functionality of at least 3, and wherein the polyol compound in the first polyol component is derived from the polyol compound in the second polyol component; adding water to the single-phase product mixture to form a split-phase mixture, wherein the split-phase mixture comprises a polyamine-rich organic phase and a polyol-rich aqueous phase; and separating the split-phase mixture to isolate the polyamine-rich organic phase and the polyol-rich aqueous phase.

Description

1 EU-51163A METHOD OF RECOVERING RAW MATERIALS FROM RIGID POLYURETHANEFIELD OF INVENTION

[0001] The present disclosure relates to an improved method of recovering raw materials from rigid polyurethane products, specifically an improved glyco-hydrolysis method. The recovered raw materials include polyol compounds and polyamine compounds. The recovered materials may be used to produce further polyurethane products.BACKGROUND

[0002] Recovering raw materials from polyurethane products (i.e., recycling of polyurethane products) is of fundamental importance in green chemistry. Much research has been focussed on finding suitable methods to recycle polyurethane products, including glycohydrolysis methods. Glyco-hydrolysis of a polyurethane refers to the breaking down of the polyurethane into its building blocks, namely polyols (derived from the polyols used to form the polyurethane) and poly amines (derived from the polyisocyanates used to form the polyurethane). A glycolysis agent and water are used as the reactive components, as well as polyurethane, in the glyco-hydrolysis. Glyco-hydrolysis is a well-known method, and it has been used with success to chemically recycle flexible polyurethanes.

[0003] However, when it comes to recycling rigid polyurethanes, glyco-hydrolysis has been less successful due to the difficult separation of polyols and polyamines. One reason for this is that rigid polyurethanes are made from rigid polyols, which are not as easy to separate from the polyamines as flexible polyols. A current method to chemically recycle rigid polyurethane is single-phase glycolysis. However, the obtained polyols usually have a higher hydroxyl value than the polyols used to make the polyurethane, and the obtained polyols often contain large amounts of polyamines. Moreover, the single-phase product contains large amounts of amines and short chain urethanes, which is non-ideal.

[0004] Thus, a simple method is needed to chemically recycle polyurethane products, in which the extraction of the polyols from the product mixture leads to (i) polyols more closely matched to the polyols used to make the polyurethane and (ii) a lower amount of polyamines in the obtained polyol.

[0005] The present disclosure addresses the problems and needs mentioned above.SUMMARY2 EU-51163

[0006] In a first aspect, there is provided a method of recovering raw materials from a rigid polyurethane product, the method comprising: i) performing a glyco-hydrolysis reaction on a rigid polyurethane product to form a single-phase product mixture comprising a first polyol component and a polyamine component, wherein a glycolysis agent, water and the rigid polyurethane are reactants in the glyco-hydrolysis reaction, wherein the first polyol component comprises a polyol compound having an OH value of at least 250 KOH / g and an average hydroxyl functionality of at least 3, wherein the rigid polyurethane product is the reaction product of a second polyol component and an isocyanate component, the second polyol component comprising a polyol compound having an OH value of at least 250 and an average hydroxyl functionality of at least 3, and wherein the polyol compound in the first polyol component is derived from the polyol compound in the second polyol component; ii) adding water to the single-phase product mixture to form a split-phase mixture, wherein the split-phase mixture comprises a polyamine-rich organic phase and a polyol-rich aqueous phase; and iii) separating the split-phase mixture to isolate the polyamine-rich organic phase and the polyol-rich aqueous phase.

[0007] Adding water to the single-phase product mixture to form a split-phase mixture enables the separation of the polyol-rich aqueous phase with a high amount of polyol and a low amount of polyamine present in the polyol-rich aqueous phase. Due to the low amount of polyamine present in the polyol-rich aqueous phase, this phase may be dried (water removed) and used directly in preparing a new polyurethane. The properties of the new polyurethane are better maintained if a high amount of polyol is present in the aqueous phase. The prior art methods to date typically extract the polyol-rich aqueous phase with an organic solvent (such as ethyl acetate), which leads to a higher amount of polyamines in the polyol-rich aqueous phase. These polyamines then need removing from the polyol-rich aqueous phase before it can be used to effectively prepare a new polyurethane.

[0008] In a second aspect, there is provided a polyol mixture obtained by the method according to the present disclosure.

[0009] The embodiments described should not be read to limit or otherwise narrow the scope of any inventive concepts otherwise provided by the present disclosure. While multiple embodiments are disclosed, other embodiments will become apparent to those skilled in the art from the following description. Accordingly, the description is to be regarded as illustrative rather than restrictive.3 EU-51163DETAILED DESCRIPTION

[0010] [Method of recovering raw materials from a rigid polyurethane product]

[0011] As used herein, the term “method of recovering raw materials from a rigid polyurethane product” refers to chemically recycling a rigid polyurethane product in order to obtain raw materials. The term “raw materials” refers to the products derived from the break down of polyurethane by a glyco-hydrolysis method. These include polyols and polyamines.

[0012] [Rigid polyurethane product]

[0013] As used herein, the term “rigid polyurethane” refers to a polyurethane which is the reaction product of a second polyol component and an isocyanate component, the second polyol component comprising a polyol compound having an OH value of at least 250 and an average hydroxyl functionality of at least 3. Such a polyol compound is termed a “rigid polyol” in the art. The rigid polyol typically provides the polyurethane with rigidity, energy efficiency and dimensional stability. Polyols having an OH value and / or an average hydroxyl functionality below said values may be referred to as “flexible polyols”, which are suitable for producing flexible polyurethanes.

[0014] In one embodiment, the rigid polyurethane product is a foam. The product may be a waste product, which would otherwise be scrapped or go to landfill.

[0015] In one embodiment, the second polyol component comprises at least one polyol compound, and may comprise two, three, four, five or more different polyol compounds.

[0016] In one embodiment, the polyol compound has an OH value (hydroxyl value or hydroxyl number) of from 250 to 1000 KOH / g, or from 300 to 900 KOH / g, or from 300 to 800 KOH / g, or from 350 to 700 KOH / g, or from 400 to 600 KOH / g, or from 400 to 550 KOH / g. In one embodiment, the polyol compound has an OH value (hydroxyl value or hydroxyl number) of at least 250 KOH / g, or at least 300 KOH / g, or at least 350 KOH / g. The OH value of a polyol can be measured using ASTM-D4274-21.

[0017] In one embodiment, the polyol compound has an average hydroxyl functionality of from 3 to 10, or from 3 to 9, or from 3 to 8, or from 3 to 7, or from 3 to 6, or from 4 to 6. As used herein, the “average hydroxyl functionality” refers to the number average functionality, as commonly used in the art. The average hydroxyl functionality of a polyol compound refers to the average number of OH groups in each molecule.

[0018] In one embodiment, the viscosity at 25°C of the polyol compound may be at least 1000 mPa.s, or from 1000 to 50,000 mPa.s, or from 2500 to 40,000 mPa.s, or from 5000 to4 EU-5116340,000 mPa.s. The viscosity may be measured using a Brookfield DV-II viscometer at 25°C.

[0019] In one embodiment, the polyol compound has an OH value (hydroxyl value or hydroxyl number) of from 250 to 1000 KOH / g and an average hydroxyl functionality of from 3 to 10. In another embodiment, the polyol compound has an OH value (hydroxyl value or hydroxyl number) of from 300 to 900 KOH / g and an average hydroxyl functionality of from 3 to 9. In another embodiment, the polyol compound has an OH value (hydroxyl value or hydroxyl number) of from 350 to 700 KOH / g and an average hydroxyl functionality of from 3 to 6.

[0020] The polyol compound is not particularly limited, and any known polyol compound may be used, providing it fulfils the required OH value and average hydroxyl functionality. In one embodiment, the polyol compound may be any one selected from a polyether polyol, a polyester polyol, a polyether-ester polyol, a polycaprolactone polyol, a polycarbonate polyol, and a combination thereof.

[0021] In one embodiment, the polyol compound may be a poly ether compound. The poly ether compound may be prepared by reacting one or more initiators with one or more alkylene oxides in the presence of a suitable catalyst. Suitable initiators include glycerol, diethylene glycol, trimethylolpropane, pentaerythritol, glucose, mannitol, sucrose, sorbitol, triethanol amine, ethylene diamine, or a combination thereof. Combinations of initiators may be used, such as sucrose and DEG. Suitable alkylene oxides include ethylene oxide, propylene oxide, butylene oxide, or a combination thereof. In one embodiment, the polyol compound is selected from a sucrose-initiated polyol and a sorbitol -initiated polyol. Particularly preferred polyol compounds are formed from sorbitol (optionally in combination with water) or sucrose (optionally in combination with diethylene glycol) (as an initiator) and propylene oxide. The skilled person knows how to prepare such polyols as the method is common in the art, and a detailed description thereof is omitted. The present inventors have found that polyol compounds initiated from sucrose and sorbitol have an affinity for the aqueous phase during extraction of the product mixture. In contrast, aromatic amine-initiated polyol compounds have an affinity for the organic phase during extraction of the product mixture.

[0022] In one embodiment, the polyol compound is selected from a sucrose-initiated polyol, a sorbitol-initiated polyol, a sucrose-DEG-initiated polyol, and a sorbitol-water-initiated polyol. Preferably, the alkylene oxide which is used to form the sucrose-initiated polyol,5 EU-51163 the sorbitol-initiated polyol, the sucrose-DEG-initiated polyol, and the sorbitol-water- initiated polyol is propylene oxide.

[0023] The isocyanate component is not particularly limited, and any known isocyanate component may be used. The isocyanate component may comprise an aliphatic polyisocyanate, an aromatic polyisocyanate, a prepolymer of a polyisocyanate, or a combination thereof. Preferably, the isocyanate component comprises an aromatic polyisocyanate compound, more preferably a methylene diphenyl diisocyanate (MDGbased compound. The isocyanate component may be pure MDI, polymeric MDI, or may be a prepolymer thereof, i.e., a prepolymer made from MDI and a polyol. According to an embodiment, the isocyanate component may comprise at least 50 weight%, or at least 75 weight%, or at least 80 weight%, or at least 85 weight%, or at least 90 weight%, or at least 95 weight%, or about 100 weight%, of an aromatic polyisocyanate, such as MDI-based polyisocyanate, based upon the total weight of the isocyanate component.

[0024] Examples of aliphatic polyisocyanates suitable for use in the isocyanate component include, but are not limited to, hexamethylene diisocyanate (HDI), tetraalkyl xylene diisocyanate, cyclohexane diisocyanate, 1,12-dodecane diisocyanate, 1,4- tetramethylene diisocyanate, 1,3- and 1,4-cyclohexane diisocyanate, 1-isocyanato- 3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (isophorone diisocyanate), 4,4'-, 2,2'- or 2,4'-dicyclohexyl-methane diisocyanate, as well as the corresponding isomer mixtures.

[0025] Examples of aromatic polyisocyanates suitable for use in the isocyanate component include, but are not limited to, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'- or 2,4'- or 2,2'-diphenylmethane diisocyanate (MDI), polymeric MDI, 2,4- or 2,6- toluene diisocyanate (TDI), dianisidine diisocyanate, bitolylene diisocyanate, naphthal ene-l,4-diisocyanate and diphenylene 4,4'-diisocyanate.

[0026] Prepolymers formed from the reaction of a polyisocyanate (e.g., MDI, modified MDI and / or polymeric-MDI) with a polyol may also be suitable for use in the isocyanate component. The polyol may be a polyether polyol, a polyester polyol, a polycarbonate polyol, a polycaprolactone polyol, other polyol which may be used either individually or in combinations of two or more, or a combination thereof. In addition, the polyol may be a copolymer of one or more of a polyether polyol, a polyester polyol, a polyether-ester polyol, a polycarbonate polyol, a polycaprolactone polyol, or other polyol.6 EU-51163

[0027] According to an embodiment, the isocyanate component may comprise an isocyanate- terminated prepolymer. The isocyanate-terminated prepolymer may be prepared by reaction of an excessive amount of a polyisocyanate having at least 80 weight%, or at least 85 weight%, or at least 90 weight%, or at least 95 weight%, of MDI (such as 4,4'- MDI) with a suitable difunctional polyol in order to obtain a prepolymer having a desired NCO value. Methods to prepare prepolymers have been described in the art. The relative amounts of polyisocyanate and polyol depend on their equivalent weights and on the desired NCO value and can be determined easily by those skilled in the art. The NCO value of the isocyanate-terminated prepolymer is preferably above 3%, preferably above 5%, more preferably above 8%, and more preferably above 10%. The NCO value of the isocyanate-terminated prepolymer may be from 3% to 40%, or from 5% to 30%, or from 10% to 20%.

[0028] In one embodiment, the polyol compound is a polyether polyol having an OH value (hydroxyl value or hydroxyl number) of from 250 to 1000 KOH / g and an average hydroxyl functionality of from 3 to 10, and the isocyanate component comprises an aromatic polyisocyanate.

[0029] In one embodiment, the polyol component and the isocyanate component may be mixed at an isocyanate index suitable to form a rigid polyurethane, in the presence of suitable catalysts and optional additives such as surfactants and blowing agents. In one embodiment, the polyol component comprises from 10 to 100 wt%, or from 20 to 90 wt%, or from 30 to 90 wt%, or from 40 to 85 wt%, of the polyol compound having an OH value of at least 250 and an average hydroxyl functionality of at least 3, based upon the total weight of the polyol component.

[0030] In one embodiment, the isocyanate index is from 100 to 400, or from 100 to 350.

[0031] As used herein, the isocyanate index refers to the ratio of isocyanate groups (NCO- groups) over isocyanate-reactive hydrogen atoms present in a composition:[NCO] x 100[active hydrogen]In other words, the isocyanate index expresses the percentage of isocyanate used in a composition with respect to the amount of isocyanate theoretically required for reacting with the amount of isocyanate-reactive hydrogen used in the composition. It should be observed that the isocyanate index as used herein is considered from the point of view of the actual polymerisation process preparing the material involving the isocyanate ingredient and the isocyanate-reactive ingredients. Any isocyanate groups consumed7 EU-51163 in a preliminary step to produce modified polyisocyanates (including such isocyanatederivatives referred to in the art as prepolymers) or any active hydrogens consumed in a preliminary step (e.g. reacted with isocyanate to produce modified polyols or polyamines) are not taken into account in the calculation of the isocyanate index. Only the free isocyanate groups and the free isocyanate-reactive hydrogens (including those of water, if used) present at the actual polymerisation stage are taken into account.

[0032] [Glyco-hydrolysis reaction and separation of products]

[0033] Step i) of the method of the present disclosure performs a glyco-hydrolysis reaction on the rigid polyurethane product to form a single-phase product mixture comprising a first polyol component and a polyamine component, wherein a glycolysis agent, water and the rigid polyurethane are reactants in the glyco-hydrolysis reaction.

[0034] A glyco-hydrolysis reaction refers to the breaking down of the polyurethane into its building blocks, namely polyols (derived from the polyols used to form the polyurethane) and poly amines (derived from the polyisocyanates used to form the polyurethane). A glycolysis agent and water are used as the reactive components, as well as polyurethane, in the glyco-hydrolysis. The method is well-known in the art.

[0035] In one embodiment, the glyco-hydrolysis reaction occurs for a length of time required to fully break down the polyurethane product, i.e. there is substantially no polyurethane left in the mixture. In one embodiment, the glyco-hydrolysis reaction occurs for from 1 hour to 10 hours, or from 2 hour to 8 hours, or from 2 hours to 5 hours. In one embodiment, the mixture is heated to a temperature of from 130°C to 250°C, or from 150°C to 230°C, or from 160°C to 210°C. The skilled person would be aware that the length of time and temperature required for glycolysis and hydrolysis depends on the reagents used in the reaction, such as the type and amount of foam and the glycolysis agent, and would choose suitable times and temperatures accordingly.

[0036] Any known way to perform the glyco-hydrolysis may be performed. In one embodiment, the glyco-hydrolysis reaction on the rigid polyurethane product comprises the steps: A) forming a reaction mixture comprising the glycolysis agent, water and the rigid polyurethane product; and B) reacting the reaction mixture to form the single-phase product mixture.

[0037] In another embodiment, the glyco-hydrolysis reaction on a rigid polyurethane product comprises the steps: 1) forming a single-phase glycolysis mixture comprising the glycolysis agent and the rigid polyurethane product; 2) reacting the glycolysis mixture to form a glycolysis product mixture; and 3) adding water to the glycolysis product8 EU-51163 mixture to form the single-phase product mixture. In one embodiment, in step 3), the water is added to the glycolysis product mixture at a rate of between 0.05 to 0.3 ml EbO / min per 100 grams of glycolysis product mixture, preferably between 0.05 to 0.2 ml EEO / min per 100 grams of glycolysis product mixture. In one embodiment, the glycolysis reaction (steps 1 and 2) occurs for a length of time from 30 mins to 4 hours, or from 1 hour to 4 hours, or from 2 hours to 4 hours. In one embodiment, the hydrolysis reaction (step 3) occurs for a length of time from 30 mins to 8 hours, or from 1 hour to 5 hours, or from 2 hours to 4 hours. The skilled person would be aware that the length of time and temperature required for glycolysis and hydrolysis depends on the reagents used in the reaction, such as the type and amount of foam and the glycolysis agent, and would choose suitable times and temperatures accordingly.

[0038] The glycolysis agent may be any known agent used in the art. In one embodiment, the glycolysis agent is a diol compound, preferably a diol compound containing 2 to 6 carbon atoms. Suitable diol compounds include monoethylene glycol (MEG), di ethylene glycol (DEG), propylene glycol, dipropylene glycol and 1,4-butanediol. Another suitable glycolysis agent is glycerol.

[0039] In one embodiment, the reaction mixture in step A) or the glycolysis mixture in step 1) further comprises a glycolysis catalyst. Suitable glycolysis catalysts are known in the art and include metal hydroxides, preferably KOH. Other non-limiting examples of catalysts suitable for use in the method of the present disclosure may include (organo)tin and bismuth catalysts such as dimethyltin dichloride, butyltin trichloride, dimethyltin dilaurate, dimethyltin dioleate, dimethyltin mercaptide, dibutyltin diacetate, dimethyltin dineodecanoate, bismuth(III) neodecanoate, bismuth 2- ethylhexanoate and triphenylbismuth, alkali metals, titanium(IV) alkoxides such as titanium(IV) propoxide, titanium(IV) butoxide and titanium(IV) tert- butoxide, alkoxide complexes of lithium and potassium such as lithium t-butoxide and potassium t-butoxide, tetrabutyltitanate, potassium acetate, potassium 2- ethylhexanoate, calcium 2-ethylhexanoate, bismuth(III) trifluoromethanesulfonate, iron(III) acetyl aceton ate, aluminium isopropoxide, dimethylimidazole, potassium adipate and in general urethane-reaction promoting catalysts.

[0040] The single-phase product mixture comprises a first polyol component and a polyamine component. As used herein, single-phase mixture refers to a liquid mixture which is substantially a single phase, i.e. the components are mixed throughout the mixture and there is no visible and / or substantial separation between the components.9 EU-51163

[0041] The first polyol component and the polyamine component are products derived from the glyco-hydrolysis of the polyurethane. The first polyol component comprises a polyol compound, which is derived from the polyol compound in the second polyol component described above. One or more polyol compounds may be present in the first polyol component. When the polyurethane is broken down, the polyol(s) used to form the polyurethane is a product. The polyamine component comprises a polyamine, which is derived from the polyisocyanate used to form the polyurethane. For example, if MDI is used to form the polyurethane, the polyamine will typically include DADPM (any isomer thereof, such as 4,4’ -diaminodiphenylmethane). One or more polyamine compounds may be present in the polyamine component.

[0042] The polyol compound in the first polyol component and the polyol compound in the second polyol component may be the same in chemical structure. The above description regarding the properties of the polyol compound in the second polyol component apply to the polyol compound in the first polyol component. More than one polyol compound in the first polyol component and the second polyol component may be the same in each polyol component. Each of the first and second polyol components may comprise further polyol compounds which are only present in that polyol component.

[0043] The polyol compound in the first polyol component is derived from the rigid polyurethane product. In one embodiment, the polyol compound in the first polyol component is the same in chemical structure as the polyol compound in the second polyol component.

[0044] In step ii) of the method of the present disclosure, water is added to the single-phase product mixture to form a split-phase mixture. As used herein, split-phase mixture refers to a mixture in which there are two visibly distinct phases.

[0045] Once water is added, the mixture may be shaken or agitated. The split-phase will form over time.

[0046] In one embodiment, the amount of water added to the single-phase product mixture is at least a quarter, or at least a half, of the weight of the total single-phase product mixture. In one embodiment, the amount of water added to the single-phase product mixture is from a half to twice, or equal to twice, the weight of the total single-phase product mixture. In one embodiment, the amount of water added to the single-phase product mixture is approximately equivalent to the weight of the total single-phase product mixture.10 EU-51163

[0047] In one embodiment, the method comprises a further water wash / extraction of the isolated polyamine-rich organic phase. Then, the collected aqueous phase is added to the polyol-rich aqueous phase.

[0048] The split-phase mixture comprises a polyamine-rich organic phase and a polyol-rich aqueous phase. As used herein, polyamine-rich organic phase refers to an organic phase which has a larger total amount of polyamine component relative to the polyol-rich aqueous phase. As used herein, the polyol-rich aqueous phase refers to an aqueous phase which has a larger total amount of first polyol component relative to the polyamine-rich organic phase. The polyol-rich aqueous phase contains the polyol compound of the first polyol component. Substantially no polyol compound of the first polyol component is present in the polyamine-rich organic phase (however trace amounts may be present). In one embodiment, the split-phase mixture consists essentially of, or consists of, a polyamine-rich organic phase and a polyol-rich aqueous phase. Small amounts of solids may be present in the mixture.

[0049] In one embodiment, the polyol-rich aqueous phase contains more than 50 weight%, or at least 55 weight%, or at least 60 weight%, or at least 65 weight%, or at least 70 weight%, or at least 75 weight%, of the first polyol component in the split-phase mixture, based upon the total weight of the first polyol component in the split-phase mixture.

[0050] In one embodiment, the polyol-rich aqueous phase contains less than 20 weight%, or less than 15 weight%, or less than 10 weight%, or less than 5 weight%, or less than 1 weight%, of polyol compounds which contain an amine group, based upon the total weight of the polyol compounds containing an amine group in the split-phase mixture.

[0051] In one embodiment, the polyol -rich aqueous phase contains less than 20 weight0 / ), or less than 15 weight0 / ), or less than 10 weight0 / ), or less than 7 weight0 / ), or less than 5 weight0 / ), or less than 2 weight0 / ), of the polyamine component, based upon the total weight of the polyamine component in the split-phase mixture.

[0052] In one embodiment, the polyol-rich aqueous phase does not contain any compounds which have a urethane or urea functional group. In one embodiment, the polyol-rich aqueous phase contains less than 5 weight0 / ), or less than 3 weight0 / ), or less than 1 weight0 / ), based upon the total weight of the polyol-rich aqueous phase, of compounds which have a urethane or urea functional group.

[0053] In one embodiment, the polyamine-rich organic phase contains at least 70 weight0 / ), or at least 75 weight0 / ), or at least 80 weight0 / ), or at least 85 weight0 / ), or at least 90 weight0 / ), or at least 93 weight0 / ), or at least 95 weight0 / ), or at least 98 weight0 / ), of the11 EU-51163 polyamine component in the split-phase mixture, based upon the total weight of the polyamine component in the split-phase mixture.

[0054] In one embodiment, the polyamine-rich organic phase does not contain any compounds which have a urethane or urea functional group. In one embodiment, the polyamine- rich organic phase contains less than 5 weight%, or less than 3 weight%, or less than 1 weight%, based upon the total weight of the polyamine-rich organic phase, of compounds which have a urethane or urea functional group.

[0055] The organic phase and aqueous phase form separate layers and can be separated and isolated by conventional means.

[0056] In one embodiment, the method described herein further comprises a step of removing the water from the polyol-rich aqueous phase to form a polyol mixture. Any known method of removing water from the mixture may be applied, including evaporation. The polyol mixture comprises polyol compounds from the first polyol component. In one embodiment, the polyol mixture may be used to prepare a new rigid polyurethane product.

[0057] The present disclosure also provides a polyol mixture obtained by the method described herein. The polyol mixture is derived from the rigid polyurethane product, and includes the polyol compound in the first polyol component. The polyol mixture obtained by the method described herein is the above-described polyol mixture obtained after removal of water from the polyol-rich aqueous phase.

[0058] [Non-limiting embodiments]

[0059] In an embodiment of the present disclosure, there is provided a method of recovering raw materials from a rigid polyurethane product, the method comprising: i) performing a glyco-hydrolysis reaction on a rigid polyurethane product to form a single-phase product mixture comprising a first polyol component and a polyamine component, wherein a glycolysis agent, water and the rigid polyurethane are reactants in the glyco-hydrolysis reaction, wherein the first polyol component comprises a polyol compound having an OH value of at least 250 KOH / g and an average hydroxyl functionality of at least 3, wherein the rigid polyurethane product is the reaction product of a second polyol component and an isocyanate component, the second polyol component comprising a polyol compound having an OH value of at least 250 and an average hydroxyl functionality of at least 3, and12 EU-51163 wherein the polyol compound in the first polyol component is derived from the polyol compound in the second polyol component; ii) adding water to the single-phase product mixture to form a split-phase mixture, wherein the split-phase mixture comprises a polyamine-rich organic phase and a polyol-rich aqueous phase; and iii) separating the split-phase mixture to isolate the polyamine-rich organic phase and the polyol-rich aqueous phase, wherein the polyol-rich aqueous phase comprises the polyol compound in the first polyol component, and wherein the polyol-rich aqueous phase contains less than 10 weight% of poly amine component, based upon the total weight of the poly amine component in the split-phase mixture.

[0060] In an embodiment of the present disclosure, there is provided a method of recovering raw materials from a rigid polyurethane product, the method comprising: i) performing a glyco-hydrolysis reaction on a rigid polyurethane product to form a single-phase product mixture comprising a first polyol component and a polyamine component, wherein a glycolysis agent, water and the rigid polyurethane are reactants in the glyco-hydrolysis reaction, wherein the first polyol component comprises a polyol compound having an OH value of at least 350 KOH / g and an average hydroxyl functionality of at least 3.5, wherein the rigid polyurethane product is the reaction product of a second polyol component and an isocyanate component, the second polyol component comprising a polyol compound having an OH value of at least 350 KOH / g and an average hydroxyl functionality of at least 3.5, and the isocyanate component comprising an aromatic polyisocyanate, and wherein the polyol compound in the first polyol component is derived from the polyol compound in the second polyol component; ii) adding water to the single-phase product mixture to form a split-phase mixture, wherein the split-phase mixture comprises a polyamine-rich organic phase and a polyol-rich aqueous phase, wherein the amount of water added to the singlephase product mixture is at least a half of the weight of the total single-phase product mixture; and13 EU-51163 iii) separating the split-phase mixture to isolate the polyamine-rich organic phase and the polyol-rich aqueous phase, wherein the polyol-rich aqueous phase comprises the polyol compound in the first polyol component, and wherein the polyol-rich aqueous phase contains less than 10 weight% of poly amine component, based upon the total weight of the poly amine component in the split-phase mixture.

[0061] In an embodiment of the present disclosure, there is provided a method of recovering raw materials from a rigid polyurethane product, the method comprising: i) performing a glyco-hydrolysis reaction on a rigid polyurethane product to form a single-phase product mixture comprising a first polyol component and a polyamine component, wherein a glycolysis agent, water and the rigid polyurethane are reactants in the glyco-hydrolysis reaction, wherein the first polyol component comprises a polyol compound having an OH value of at least 350 KOH / g and an average hydroxyl functionality of at least 3.5, wherein the rigid polyurethane product is the reaction product of a second polyol component and an isocyanate component, the second polyol component comprising a polyol compound having an OH value of at least 350 KOH / g and an average hydroxyl functionality of at least 3.5, and the isocyanate component comprising an aromatic polyisocyanate, wherein the polyol compound is obtained by reacting at least one initiator selected from sucrose and sorbitol with at least one alkylene oxide selected from ethylene oxide and propylene oxide, and wherein the polyol compound in the first polyol component is derived from the polyol compound in the second polyol component; ii) adding water to the single-phase product mixture to form a split-phase mixture, wherein the split-phase mixture comprises a polyamine-rich organic phase and a polyol-rich aqueous phase, wherein the amount of water added to the singlephase product mixture is at least a half of the weight of the total single-phase product mixture; and iii) separating the split-phase mixture to isolate the polyamine-rich organic phase and the polyol-rich aqueous phase, wherein the polyol-rich aqueous phase comprises the polyol compound in the first polyol component, and14 EU-51163 wherein the polyol-rich aqueous phase contains less than 10 weight% of poly amine component, based upon the total weight of the poly amine component in the split-phase mixture.

[0062] [Examples]

[0063] The present disclosure will be described in more detail with reference to the Examples. The present disclosure is not limited to the following Examples.

[0064] The rigid foam used in the following examples corresponds to a foam made from the foam A composition below:

[0065] SUPRASEC® 5025 (polymeric MDI, Fn 2.7)

[0066] Polyol A: sucrose / DEG initiated poly ether polyol of OH value 160, Fn=2.4

[0067] Polyol B: sucrose / DEG initiated poly ether polyol of OH value 440, Fn=4.2

[0068] Polyol C: Sorbitol initiated polyether polyol of OH value 510, Fn=5.5

[0069] Polyol D: DADPM / DEG initiated polyether polyol of OH value 500, Fn = 3.3

[0070] Polyols A-D were made by reacting the initiator with propylene oxide (PO).

[0071] As used herein, “Fn” refers to the average functionality of the polyisocyanate (NCO groups) or the polyol (OH groups). The OH value are measured as described herein.

[0072] [Example 1]

[0073] 1.5 parts (60 grams) diethylene glycol with 1 weight% KOH (based upon the amount of foam used) was poured into a glass vessel and was heated to 200°C while stirring under a nitrogen blanket. 1.0 part (40 grams) of small cut pieces of rigid foam (Foam A) was gradually added in small amounts, leaving time to dissolve the foam in between15 EU-51163 each addition of foam. After addition of the foam, the glycolysis mixture was reacted for 3 hours, at 200°C. After this time, 16.7 ml of water was added at a rate of 0.1 ml / min to start hydrolysis for 167 mins. The reaction of urethane groups to DADPM was monitored via thin layer chromatography to determine the end of the hydrolysis. After 167 mins, the single-phase product mixture was cooled down and water was added (in an amount equal to the weight of the product mixture, a 1 : 1 weight ratio of the product mixture to the added water). The reaction vessel was shaken, and the mixture was allowed to settle into two phases. The top phase (polyol-rich phase) was collected and the water removed by rotavap. The bottom phase was a polyamine-rich phase.

[0074] 13C NMR analysis on the top and bottom phases showed the following:

[0075] Top phase: contained approximately 67 wt% of the total polyols in the two phases. In the top phase, sucrose-PO and sorbitol-PO polyols were present. However, only trace amounts of DADPM-PO polyol was present. 5.7 wt% of the total aromatic amines (polyamines) in the two phases were present in the top phase. No urethane or urea groups were detected in the top phase.

[0076] Bottom phase: contained approximately 33 wt% of the total polyols in the two phases. In the bottom phase, sucrose / DEG-PO, sorbitol-PO and all of the DADPM-PO polyols were present. 94.3 wt% of the total aromatic amines (polyamines) in the two phases were present in the bottom phase. Traces of urethane or urea groups were detected in the bottom phase.

[0077] [Comparative Example 1]

[0078] Approximately 1.5 parts (303 grams) diethylene glycol with 1 weight% KOH (based upon the amount of foam) was poured into a glass vessel and was heated to 200°C while stirring under a nitrogen blanket. 1.0 part (200 grams) of small cut pieces of rigid foam (Foam A) was gradually added in small amounts, leaving time to dissolve the foam in between each addition of foam. After addition of the foam, the glycolysis mixture was reacted for 3 hours, at 200°C. However, no split phase was formed.

[0079] [Comparative Example 2]

[0080] Approximately 5 parts (101 grams) monoethylene glycol with 10 weight% KOH (based upon the amount of foam) was poured into a glass vessel and was heated to 170°C while stirring under a nitrogen blanket. 1 part (18 grams) of small cut pieces of rigid foam (Foam A) was gradually added in small amounts, leaving time to dissolve the foam in between each addition of foam. After addition of the foam, the glycolysis mixture was reacted for 2 hours, at 170°C. However, no split phase was formed.16 EU-51163

[0081] As can be seen from Example 1 and Comparative Examples 1 and 2, the method according to the present disclosure allows for isolation and separation, in good yields, of the polyols when recycling polyurethane. In contrast, known glycolysis methods do not form a split phase when recycling rigid polyurethane foams. Moreover, the amount of polyamine compounds in the polyol-rich phase in Example 1 is low, and therefore the isolated polyol-rich phase may be used in preparing a polyurethane without further purification.

[0082] All ranges described herein are exemplary in nature and include any and all values in between. The terms “substantially”, “approximately” and “about” used herein are interchangeable and refer to a measurement that includes the stated measurement and any measurements reasonably close to the stated measurement. Measurements that are reasonably close to the stated measurement deviate from the stated measurement by a reasonably small amount as understood and readily ascertained by individuals having ordinary skill in the relevant art. Such deviations may be attributable to measurement error, differences in measurement and / or manufacturing equipment calibrations, human error in reading and / or setting measurements, minor adjustments made to optimize performance and / or structural parameters in view of differences in measurement associated with other components, particular implementation scenarios, imprecise adjustment and / or manipulation of objects by a person or machine. In the event it is determined that individuals having ordinary skill in the relevant art would not readily ascertain values for such reasonably small differences, the terms “about” and “approximately” can be understood to mean plus or minus 10% of the stated value.

[0083] Throughout the description and claims, the terms take the meanings explicitly defined herein, unless the context clearly dictates otherwise.

[0084] The phrases “in one embodiment”, “in an embodiment” and “in some embodiments” etc. as used herein do not necessarily refer to the same embodiment(s), though they may. Furthermore, the phrases “in another embodiment” and “in some other embodiments” as used herein do not necessarily refer to a different embodiment, though they may. All embodiments of the present disclosure are intended to be combinable.

[0085] The terms “comprises” and “comprising” mean to include but not limited to, such that further features may be present. The terms may also mean to consist of or consist essentially of.

[0086] All references and test methods cited herein are incorporated by reference in their entireties.

Claims

17 EU-51163CLAIMS1. A method of recovering raw materials from a rigid polyurethane product, the method comprising: i) performing a glyco-hydrolysis reaction on a rigid polyurethane product to form a single-phase product mixture comprising a first polyol component and a polyamine component, wherein a glycolysis agent, water and the rigid polyurethane are reactants in the glyco-hydrolysis reaction, wherein the first polyol component comprises a polyol compound having an OH value of at least 250 KOH / g and an average hydroxyl functionality of at least 3, wherein the rigid polyurethane product is the reaction product of a second polyol component and an isocyanate component, the second polyol component comprising a polyol compound having an OH value of at least 250 KOH / g and an average hydroxyl functionality of at least 3, and wherein the polyol compound in the first polyol component is derived from the polyol compound in the second polyol component; ii) adding water to the single-phase product mixture to form a split-phase mixture, wherein the split-phase mixture comprises a polyamine-rich organic phase and a polyol-rich aqueous phase; and iii) separating the split-phase mixture to isolate the polyamine-rich organic phase and the polyol-rich aqueous phase.

2. A method according to Claim 1, wherein performing the glyco-hydrolysis reaction on a rigid polyurethane product comprises the steps:A) forming a reaction mixture comprising the glycolysis agent, water and the rigid polyurethane product; andB) reacting the reaction mixture to form the single-phase product mixture.

3. A method according to Claim 1, wherein performing the glyco-hydrolysis reaction on a rigid polyurethane product comprises the steps:1) forming a glycolysis mixture comprising the glycolysis agent and the rigid polyurethane product;2) reacting the glycolysis mixture to form a glycolysis product mixture; and18 EU-511633) adding water to the glycolysis product mixture to form the single-phase product mixture.

4. A method according to any preceding claim, wherein the polyol compound in the second polyol component is obtained by reacting an initiator selected from diethylene glycol (DEG), glycerol, sucrose, sorbitol and a combination thereof, with an alkylene oxide selected from ethylene oxide, propylene oxide, and a combination thereof.

5. A method according to Claim 2 or Claim 3, wherein the reaction mixture in step A) of Claim 2 or the glycolysis mixture in step 1) of Claim 3 further comprises a glycolysis catalyst.

6. A method according to any preceding claim, wherein the glycolysis agent is any one selected from monoethylene glycol (MEG), diethylene glycol (DEG), propylene glycol, dipropylene glycol, 1,4-butanediol, and a combination thereof.

7. A method according to any preceding claim, wherein the amount of water added to the single-phase product mixture is at least a half of the weight of the total single-phase product mixture, preferably from an equal to twice the weight of the total single-phase product mixture.

8. A method according to any preceding claim, further comprising a step of removing the water from the isolated polyol-rich aqueous phase to form a polyol mixture.

9. A method according to any preceding claim, wherein the polyol-rich aqueous phase contains at least 60 weight% of the first polyol component in the split-phase mixture, based upon the total weight of the first polyol component in the split-phase mixture10. A method according to any preceding claim, wherein the polyol-rich aqueous phase contains less than 15 weight% of the poly amine component, based upon the total weight of the poly amine component in the split-phase mixture.

11. A method according to any preceding claim, wherein the polyol compound in the first and second polyol component has an OH value of at least 350 KOH / g.19 EU-5116312. A method according to any preceding claim, wherein the polyol compound in the first and second polyol component has an average hydroxyl functionality of at least 3.5.

13. A method according to any preceding claim, wherein the isocyanate component comprises an aromatic polyisocyanate, preferably a methylene diphenyl diisocyanate (MDI)-based polyisocyanate.

14. A polyol mixture obtained by the method according to Claim 8.