Recycling polyols produced from molded polyurethane foam

Abstract

The present application relates to a method for producing a molded recycled polyurethane foam for a seat, from a molded used polyurethane foam.

Description

Description Title: Recycling of polyol produced from molded polyurethane foam technical field

[0001] This disclosure relates to the field of molded polyurethane foams for automotive seating. Specifically, this disclosure relates to the recycling of these polyol foams to produce new molded polyurethane foams. Previous technique

[0002] The synthesis of polyurethane materials (rigid and flexible foams, elastomers, adhesives, etc.) relies on the polyaddition reaction between a polyol, for example, a polyphenol, and a polyisocyanate compound. A polyol must possess specific properties to be used in the manufacture of polyurethane materials. For example, a polyol intended for the manufacture of high-resilience molded polyurethane foam for automotive seats preferably has a viscosity at 25°C between 800 mPa·s and 1200 mPa·s, and a hydroxyl value between 26 mg(KOH) / g -1 and 32 mg (KOH).g -1 and an acid value of less than 0.1 mg(KOH).g -1Indeed, a polyol with such viscosity is liquid and mixes easily with the polyisocyanate compound and any additives during the conventional manufacturing of polyurethane foam at room temperature or in a mold heated between 50 and 75°C. Furthermore, the range of hydroxyl values ​​indicated above allows for the formation of a three-dimensional cross-linked network, giving the foam, among other things, mechanical properties suitable for use in automotive seating.

[0003] Polyols and polyisocyanate compounds are petrochemical-derived polymers whose production generates significant amounts of CO2. In order to reduce dependence on oil, and also decrease the amount of CO2 emitted, it is necessary to use polyols and polyisocyanate compounds of non-petrochemical origin or recycled.

[0004] Today, used molded polyurethane seat foams are primarily incinerated or landfilled, and are therefore not recycled. They represent an alternative source to petroleum for the production of polyols, which can then be used to produce new molded polyurethane seat foams, creating a virtuous cycle of foam recycling.

[0005] Producing a polyol from these used foams that possesses the desired properties for automotive seat foam production is no easy feat. Indeed, to produce a recycled molded polyurethane foam with comfortable properties that meets the requirements of automotive seating, the depolymerization of the polyurethane in these used foams must allow for the very precise cutting of the polyurethane's cross-linked structure in order to produce small molecules containing hydroxyl groups capable of subsequently reacting with isocyanates. It is therefore to the credit of the inventors that they have found a process that meets this need. Summary

[0006] A process for producing recycled molded polyurethane foam is proposed, particularly for seats, mattresses, or sofas, more particularly for vehicle seats such as those in automobiles or aircraft, for furniture seating, and more particularly for automobile seats. This process comprises the following steps: a) acidolysis treatment of molded polyurethane foam to obtain a viscous liquid; b) mixing the viscous liquid with a first polyol and a neutralizing agent to obtain a mixture of recycled polyols; and c) contacting the mixture of recycled polyols with an additive and a polyisocyanate compound to produce the recycled molded polyurethane foam. This process is characterized in that the molded polyurethane foam is a high-resilience molded polyurethane foam, particularly for seats, mattresses, or sofas.more particularly for vehicle seats such as automobiles or airplanes, for furniture seating, more particularly for automobile seats, and the mass ratio of viscous liquid to first polyol in the recycled polyol blend is between 90:10 and 10:90, particularly between 80:20 and 20:80, especially between 50:50 and 75:25.

[0007] During step a) of the acidolysis treatment, a conventional step known to those skilled in the art, the polyurethane in the molded polyurethane foam depolymerizes to form a viscous liquid comprising amino compounds and polyols. The polyols in this viscous liquid react with the polyisocyanate compound in step c) of the process of the present invention to produce recycled molded polyurethane foam, particularly for seating, which may comprise up to 30% by mass of molded polyurethane foam.

[0008] However, the inventors found that the viscous liquid cannot be implemented as such in step c) because of its high viscosity and high acid number. Indeed, its high viscosity disrupts pumping and injection into the mold used to produce molded polyurethane foam. Furthermore, the molded polyurethane foam produced is destabilized by the high viscosity and high acid value of the viscous liquid.

[0009] Without being bound by any theory, the inventors believe that the high viscosity of the viscous liquid is due to the incomplete and / or non-selective depolymerization of the hard urethane and urea segments of the molded polyurethane foam in step a), which produces small-diameter oligomer particles (much less than 100 µm) in a liquid medium. The high acid value of the viscous liquid, on the other hand, results from the use of acid during step a), the acidolysis of the molded polyurethane foam.

[0010] It is to the credit of the inventors that they found that step b) of the process of the invention makes it possible to solve this problem. Indeed, the inventors believe that the mixture of recycled polyols exhibits a viscosity and a acid values ​​suitable for step c) are achieved thanks to the first polyol and the neutralizing agent, respectively. In particular, the viscosity and acid value of the recycled polyol mixture allow step c) to be carried out in a normal industrial setting, therefore without modification of conventional equipment.

[0011] Thus, thanks to steps a), b) and c), the process of the present invention creates a virtuous circle of recycling a significant quantity of used molded polyurethane seat foam into recycled molded polyurethane seat foam, in particular, whereas this element is not normally recycled.

[0012] Thanks to this virtuous circle, the process of the present invention makes it possible to reduce the environmental impact, to reduce the pollution generated by the incineration of used molded polyurethane seat foam, and to reduce the CO2 emission from the production chain of this foam.

[0013] The process of the present invention also makes it possible to reduce and limit the volatility of the production costs of molded polyurethane foam, in particular for seating, by limiting the amount of petroleum-based polyols incorporated into this foam.

[0014] Furthermore, the foam produced by the process of the present invention exhibits mechanical properties, in particular a density, tear propagation strength, and compression set, of the same order of magnitude as an industrial molded foam produced from petrochemical polyols and commonly used in automobile seats. The molded foam produced by the process of the present invention also exhibits a reactivity, characterized by a foam rise profile, comparable to the rise profile of an industrial foam produced from petrochemical polyols and commonly used in seats.The foam produced by the process of the present invention can therefore be used in seats, mattresses, or sofas, particularly for vehicle seats such as those in automobiles or airplanes, and for furniture, especially automobile seats. Furthermore, this foam does not require modification of the conventional industrial process for producing molded polyurethane foam, particularly for seating. The foam produced by the process of the present invention can also be applied to armrests, seat components such as headrests, vehicle dashboards, or vehicle door panels.

[0015] According to another aspect, a molded polyurethane foam is proposed, in particular for seats, mattresses or sofas, more particularly for vehicle seats such as automobiles or airplanes, for furniture seating, and more particularly for automobile seats, which can be obtained by the process of the present invention. Brief description of the drawings

[0016] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which: Fig. 1

[0017] [Fig. 1] shows a foam rise profile according to the invention (Polyol 50% and Polyol 75%) and a comparative foam. Fig. 2

[0018] [Fig. 2] shows different photos of foams according to the invention and of a reference foam. Fig. 3

[0019] [Fig. 3] shows a graph comparing the density of a foam according to the invention and a reference foam. Fig. 4

[0020] [Fig. 4] shows a graph comparing the tear resistance of a foam according to the invention and a reference foam. Fig. 5

[0021] [Fig. 5] shows a graph comparing the compression set deformation at constant thickness of a foam according to the invention and a reference foam. Description of the implementation methods

[0022] A process for producing recycled molded polyurethane foam is proposed, particularly for seats, mattresses, or sofas, more particularly for vehicle seats such as those in automobiles or aircraft, for furniture seating, and more particularly for automobile seats. This process comprises the following steps: a) acidolysis treatment of molded polyurethane foam to obtain a viscous liquid; b) mixing the viscous liquid with a first polyol and a neutralizing agent to obtain a mixture of recycled polyols; and c) contacting the mixture of recycled polyols with an additive and a polyisocyanate compound to produce the recycled molded polyurethane foam. This process is characterized in that the molded polyurethane foam is a high-resilience molded polyurethane foam, particularly for seats, mattresses, or sofas.more particularly for vehicle seats such as automobiles or airplanes, for furniture seating, more particularly for automobile seats, and the mass ratio of viscous liquid to first polyol in the recycled polyol blend is between 90:10 and 10:90, particularly between 80:20 and 20:80, especially between 50:50 and 75:25.

[0023] For the purposes of the present invention, the term "foam" as used, for example, in the expression "polyurethane foam", refers to a compound with a three-dimensional alveolar structure of the expanded type.

[0024] For the purposes of the present invention, the term "molded seat foam" means all or part of a foam having mechanical properties suitable for a seat element and produced in a mold having a shape suitable for a seat element, all or part of a waste product of this production, and mixtures thereof. Typically, molded seat foam can be foam from an End-of-Life Vehicle as defined in European Directive 2000 / 53 / EC of 18 September 2000.

[0025] For the purposes of the present invention, the term "high resilience" refers to a foam whose resilience is greater than 70% (at 5 ème compression cycle according to test method D45 5128 (PSA)).

[0026] Step a) of treatment by acidolysis is a classic step known to those skilled in the art. It is described, for example, in POLIMERY 2018, 63, no. 3, 234-238. Those skilled in the art will know how to implement it to obtain the viscous liquid, in particular a viscous liquid exhibiting the following properties: - a hydroxyl value between 20 mg(KOH).g -1 and 100 mg (KOH).g -1 , more specifically between 25 mg(KOH).g -1 and 60 mg (KOH).g -1 , - an acid value greater than 1 mg(KOH).g -1, in particular between 5 mg(KOH).g -1 20 mg (KOH) g 1 , And - a viscosity at 25°C greater than 15,000 mPa.s, in particular between 20,000 mPa.s and 50,000 mPa.s.

[0027] For the purposes of the present invention, "hydroxyl index" (also noted as 'OH index') represents the amount of potassium hydroxide in mg corresponding to the number of hydroxyl groups present in 1 g of material.

[0028] Advantageously, the range of hydroxyl index of the viscous liquid allows the obtaining of a three-dimensional cross-linked network giving the foam, among other things, mechanical properties suitable for its use in an automotive seat. However, the high viscosity of the viscous liquid disrupts its pumping and injection into the mold, enabling the production of the molded polyurethane foam. Furthermore, the molded polyurethane foam produced is destabilized by the high viscosity and high acid index of the viscous liquid.

[0029] For the purposes of this invention, "acid value" refers to the amount of residual acid in the polyol. It is expressed as the number of milligrams of potassium hydroxide required to neutralize the acid present in one gram of sample.

[0030] For the purposes of the present invention, "viscosity at 25°C" means Brookfield viscosity and / or viscosity measured by a cone-plate viscometer at 25°C.

[0031] The first polyol is a petrochemical, recycled, or bio-based polyol that allows the production of polyols with varying functionalities. The first polyol can, for example, be chosen from alkoxylated glycerol, alkoxylated sorbitol, alkoxylated diethyltriamine, alkoxylated sucrose, or polyols with polyoxypropylene glycol-based and their mixtures, in particular polyols based on polyoxypropylene glycol and their mixtures.

[0032] Caradol SA34-05, Wanol F3135, Lupranol 2095 and Lupranol 2090 are examples of commercial polyols suitable for use as the first polyol in the process of the present invention.

[0033] The neutralizing agent may be a basic inorganic salt, an amine compound or an alcohol or mixtures thereof, in particular a basic inorganic salt, an amine compound or mixtures thereof.

[0034] Typically, basic inorganic salts can be sodium hydroxide, potassium hydroxide, calcium chloride, calcium carbonate, sodium bicarbonate, and mixtures thereof.

[0035] Typically, the amino compound can be ammonia, dimethylaminopropylamine (DMAPA) and mixtures thereof.

[0036] A person skilled in the art will know how to adjust the neutralizing agent content to obtain the mixture of recycled polyols.

[0037] According to one embodiment, step b) of mixing can be carried out in 1 or more times, in particular in 1, 2, 3 or 4 times, more particularly in 1 or 2 times.

[0038] Advantageously, carrying out step b) in several stages allows the properties of the recycled polyol mixture to be adjusted at will according to demand, for example the content of molded polyurethane foam in the recycled molded polyurethane foam. This also allows step b) to be carried out at the viscous liquid production site to reduce its viscosity and facilitate its transport to the recycled molded polyurethane foam production site. At this second production site, step b) can be repeated to obtain the recycled polyol blend. This helps to limit the costs associated with transporting the first polyol.

[0039] The recycled polyol mixture may have an acid value less than or equal to 1 mg(KOH).g -1 , in particular less than or equal to 0.5 mg(KOH).g -1 and at least one, in particular the following two characteristics: - a viscosity at 25°C between 500 mPa.s and 15,000 mPa.s, and - a hydroxyl value between 20 mg(KOH).g -1 and 100 mg (KOH).g -1 , in particular between 25 mg(KOH).g -1 and 60 mg (KOH).g -1 .

[0040] These characteristics depend on the properties of the viscous liquid, particularly its viscosity and acid number, the nature of the first polyol, and the viscous liquid:first polyol mass ratio described above. A person skilled in the art will be able to adjust these parameters to obtain a blend of recycled polyols that may possess at least one, and especially two, of these characteristics.

[0041] The inventors noted that molded polyurethane foam produced from such a mixture of recycled polyols incorporated into a formulation including an additive and a polyisocyanate compound exhibits mechanical properties suitable for use in a seat. In particular, the range of hydroxyl index indicated above allows the obtaining of a three-dimensional cross-linked network giving the foam, among other things, mechanical properties suitable for its use in an automotive seat. Furthermore, molded polyurethane foam produced from such a mixture of recycled polyols is not destabilized by the viscosity and acid number of the recycled polyol mixture. In addition, the viscosity at 25°C of the recycled polyol mixture allows said recycled polyol mixture to be advantageously liquid at 25°C and to be easily incorporated into a formulation including the additive and the polyisocyanate compound during step c) to produce the recycled molded polyurethane seat foam.

[0042] According to one embodiment, the process of the present invention may further comprise, between step b) and step c): - a step of mixing the recycled polyol mixture with a second polyol to obtain a formulated polyol mixture which is then implemented in step c), the mass ratio of recycled polyol mixture:second polyol in the formulated polyol mixture being between 1:99 and 99:1, in particular between 20:80 and 80:20, especially between 50:50 and 75:25.

[0043] This mixing step can also be carried out at the same time as step b). In this case, the viscous liquid is mixed simultaneously with the first polyol and the second polyol.

[0044] Advantageously, this embodiment makes it possible to obtain the necessary conditions for casting recycled molded polyurethane foams with standard equipment such as feed pumps, injection pumps and mixing heads.

[0045] Typically, the second polyol can be chosen from among the glycerol-initiated polyoxypropylene-polyoxyethylene glycol-based polyols (triols).

[0046] Nextyol Y-3322N and Rokopol 6010 are examples of commercial polyols suitable for use as a second polyol in the process of the present invention.

[0047] The formulated polyol mixture may have an acid value of less than 1 mg(KOH).g -1 , in particular less than or equal to 0.5 mg(KOH).g -1 and at least one, in particular the following two characteristics: - a viscosity at 25°C between 500 mPa.s and 10000 mPa.s, and - a hydroxyl value between 20 mg(KOH).g -1 and 100 mg (KOH).g -1 , in particular between 25 mg(KOH).g -1 and 60 mg (KOH).g -1 .

[0048] These characteristics depend on the properties of the recycled polyol blend, the nature of the second polyol, and the first polyol:second polyol mass ratio described above. A person skilled in the art will be able to adjust these parameters to obtain a formulated polyol blend that may include at least one, and in particular two, and especially all of these characteristics.

[0049] Typically, the polyisocyanate compound can be chosen from m-phenylene diisocyanate, toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, hexamethylene 1,6-diisocyanate, tetramethylene 1,4-diisocyanate, cyclohexane 1,4-diisocyanate, hexahydrotoluene diisocyanate, naphthylene 1,5-diisocyanate, methoxyphenyl-2,4-diisocyanate, diphenylmethane 4,4'-diisocyanate and its isomers, biphenylene 4,4'-diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate, 4,4'-3,3'-dimethyldiphenylmethane diisocyanate, 4,4',4'-triphenylmethane triisocyanate, polymethylene polyphenylisocyanate, polymeric diphenylmethane diisocyanate, isophorone diisocyanate, 2,4,6-toluene triisocyanate, 4,4'-dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate, polymethylenepolyphenyl ester of isocyanic acid and mixtures thereof, in particular among 2,4-Toluene diisocyanate, 2,6-Toluene diisocyanate, 1,6-Hexamethylene diisocyanate, 4,4'-Diphenylmethane diisocyanate, polymethylene polyphenylisocyanate, polymeric diphenylmethane diisocyanate, isophorone diisocyanate, polymethylene polyphenyl ester of isocyanic acid and mixtures thereof, particularly among 4,4'-Diphenylmethane diisocyanate and its isomers, polymethylene polyphenylisocyanate, polymeric diphenylmethane diisocyanate, 2,4-Toluene diisocyanate, 2,6-Toluene diisocyanate, polymethylene polyphenyl ester of isocyanic acid and mixtures thereof, particularly again polymeric diphenylmethane diisocyanate.

[0050] The mass ratio of recycled polyols to corn-based polyisocyanate mixture can range from 1:99 to 95:5, particularly from 20:80 to 80:20, and especially from 55:50 to 75:25. A person skilled in the art will be able to adjust this ratio according to the desired properties of the high-resilience molded polyurethane foam.

[0051] An additive is also used during step c) of contacting. It allows for the modification and / or improvement of the properties of the high-resilience molded polyurethane foam produced.

[0052] Typically the additive can be chosen from a surfactant, a crosslinker, a flame retardant, a blowing agent, a release agent, an anti-hydrolysis agent, a biocide and mixtures thereof, in particular chosen from a surfactant, a crosslinker, a flame retardant, a blowing agent and mixtures thereof, more particularly be a mixture of surfactant, blowing agent and crosslinker.

[0053] For the purposes of this invention, "flame retardant (also called flame retardant)" means a compound having the property of reducing or preventing the combustion or heating of the materials it impregnates or coats. The flame retardant may, for example, be antimony, graphite, a silicate, boron, a nitrogenous, halogenated or phosphorus compound such as tris(1-chloro-2-propyl) phosphate (TCPP), triethylene phosphate (TEP), triaryl phosphate ester, ammonium polyphosphate, red phosphorus, trishalogenaryl or mixtures thereof.

[0054] For the purposes of this invention, "crosslinking agent" means a compound that generates the formation of one or more three-dimensional networks in high-resilience molded polyurethane foam. The crosslinking agent may be selected from glycerol, diethanolamine, triethanolamine, glycols with a molecular weight less than 1000 and a functionality greater than or equal to 3, and mixtures thereof, in particular diethanolamine.

[0055] For the purposes of this invention, "blowing agent" means a compound that, through chemical and / or physical action, induces the expansion of a composition during a foaming step. Typically, the chemical blowing agent is selected from water, formic acid, phthalic anhydride, and acetic acid. The physical blowing agent can be selected from pentane and pentane isomers, hydrocarbons, hydrofluorocarbons, hydrochlorofluoroolefins, hydrofluoroolefins (HFOs), ethers, and mixtures thereof. Methylal is an example of an ether-type blowing agent. According to the invention, a mixture of chemical and physical blowing agents is, for example, a mixture of water / pentane isomer, formic acid / pentane isomer, water / hydrofluoroolefins, pentane isomer / methylal / water, or water / methylal.

[0056] According to a particular embodiment, the blowing agent is water.

[0057] For the purposes of this invention, "surfactant" means an agent that provides physical stability to the polymer matrix during the progression of reactions, particularly through anti-coalescent stabilization during polymerization. Typically, the surfactant is selected from any of the following copolymers: silicone glycol, a non-hydrolyzable silicone glycol copolymer, a polyalkylene siloxane copolymer, a methylsiloxane polyoxyalkylene copolymer, a polyetherpolysiloxane copolymer, a polydimethylsiloxane polyether copolymer, a polyethersiloxane, a modified polyether-polysiloxane copolymer, a block polyoxyalkylene polysiloxane copolymer, and their derivatives or mixtures.

[0058] The release agent may be talc, a paraffin solution, silicone or mixtures thereof, or a suspension or emulsion of paraffin waxes or oils dispersed in water, a water-solvent (hybrid) mixture, or in a solvent or mixture of solvents.

[0059] The polyurethane foam produced by the process of the invention is molded. Step c) can therefore be implemented in a mold with a shape suitable for a seat element, in particular a car seat, an airplane seat, a seat for furniture, especially a car seat. Step c) can alternatively be carried out in a mold not representing a suitable shape for a seat element to produce a molded polyurethane foam, then this foam is shaped to present a suitable shape for a seat element.

[0060] The mixture of recycled polyols, the additive and the polyisocyanate compound can be pre-mixed and the resulting mixture is introduced into the mold.

[0061] It is possible to heat the mold in which step c) is carried out. Thus, reaction step c) can be implemented at a temperature between 30°C and 100°C, in particular between 40°C and 80°C, especially between 50°C and 65°C.

[0062] A catalyst can be used to accelerate the reaction kinetics between the polyol mixture and the polyisocyanate compound and between the polyisocyanate compound and the chemical blowing agent during the contacting step of the polyurethane foam manufacturing process.

[0063] Thus, according to one embodiment, step c) of the process of the present invention can be carried out in the presence of a catalyst.

[0064] The amount of catalyst used in the manufacturing process of the polyurethane foam of the invention depends on the compounds used in said process. A person skilled in the art will be able to adjust this amount.

[0065] Typically, the catalyst can be chosen from among those known to catalyze expansion (water-isocyanate) and gelation (polyol-isocyanate) reactions. Examples include N,N,N'-trimethyl-N'-hydroxyethyl-bisaminoethyl ether, bis(2-dimethyl-aminoethyl) ether, 1,3-bis[3-(dimethylamino)propyl]urea, and 2-[2-(Dimethylamino)ethoxy]ethyl[3-[[[2-[2-] (dimethylamino)ethoxy]ethoxy]carbonyl]amino]methyl]-3,5,5-trimethylcyclohexyl]carbamate, N-[2- [2-(dimethylamino) ethoxy]ethyl]-N-methyl-1,3-propanediamine (DABCO NE300), 1,4-diazabicyclooctane (TEGOAMIN 33), N'-[3-(dimethylamino)propyl]-N,N-dimethylpropane-1,3-diamine (POLYCAT 15) or mixtures thereof are catalysts that can be used in the process of the present invention.

[0066] According to one embodiment, the process may further include, before step a) of acidolysis treatment, a step of grinding the molded polyurethane foam to obtain particles having a diameter between 1 mm and 20 mm, in particular between 3 mm and 10 mm, especially between 4 mm and 6 mm, which are then implemented in step a) of acidolysis treatment.

[0067] The particle size can be determined by sieving.

[0068] The use of particles with a diameter within these ranges makes it easier and faster to depolymerize molded polyurethane foam.

[0069] Typically, this grinding step can be carried out by cryogenics followed by grinding using a vibrating ball mill, a knife mill, a hammer mill, a shredder, a centrifuge, or pulsed energy grinding, or combinations thereof. These methods are familiar to those skilled in the art. They will be able to select and implement the most suitable method for the molded polyurethane foam to be ground.

[0070] The viscous liquid obtained at the end of step a) may contain solid impurities such as pieces of foam that have not reacted with the acid. These solid impurities can affect step c) and thus alter the production process of the molded polyurethane foam produced.

[0071] To overcome these problems, the process of the present invention may further include, between step a) and step b): - a step of filtering the viscous liquid to obtain a viscous liquid free of solid particles.

[0072] The filtration stage is a standard step familiar to those skilled in the art. They will therefore know how to implement it.

[0073] Amino compounds in the viscous liquid may alter the implementation of step c) of the process of the present invention.

[0074] To overcome this problem, the process of the present invention may further include, between step a) and step b): - a deamination step of the viscous liquid to obtain a viscous liquid totally or partially free of amine compounds.

[0075] According to another aspect, a molded polyurethane foam for seating is proposed, in particular for automobile seats, for airplane seats, for furniture seating, more particularly for automobile seats, which can be obtained by the process of the present invention.

[0076] Advantageously, this molded polyurethane seat foam exhibits properties, particularly density, resistance to tear propagation, and compression set at constant thickness, of the same order of magnitude as industrial polyurethane foam produced from petrochemical-derived polyols and commonly used in automotive seats. This polyurethane foam can therefore be used in automotive seating. Examples

[0077] The following examples illustrate the invention without limiting it.

[0078] In these examples, we measure: - the hydroxyl index according to ISO 14900:2017, - acid number per ASTM D7253-22 (2022), - density according to DIN EN ISO 845 (2006) standard, - tear resistance according to standard PV3410 (2017), and - compression set according to DIN EN ISO 1856 (2018) standard,

[0079] In these examples, the foam rise profile is determined according to the following protocol. The polyol, the polyisocyanate compound, and the additives are mixed and then poured into a container for a specified duration (5 seconds). At the end of this time, a device (Universal Foam Qualification System, FORMAT Messtechnik) measures the height of expansion over time.

[0080] Example 1a: Obtaining the recycled polyol mixture

[0081] Molded polyurethane foam particles with a particle size of less than 6 mm are brought into contact with adipic acid to obtain a viscous liquid by acidolysis treatment.

[0082] The viscous liquid has the following characteristics: - hydroxyl value of 30 mg (KOH).g -1 , - acid value of 8 mg(KOH).g -1 , And - viscosity at 25°C of 35,000 mPa.s. Therefore, it cannot be used, as such, in the production of molded polyurethane foam. Its high viscosity disrupts its pumping and injection into the mold used to produce the molded polyurethane foam. Furthermore, the resulting molded polyurethane foam would be destabilized by its high viscosity and acid value.

[0083] This viscous liquid is then mixed with a first polyol, which is the Lupranol 2095 polyol (BASF), and a neutralizing agent (KOH) to obtain a mixture of recycled polyols. The mass ratio of viscous liquid to first polyol of the recycled polyol mixture is 65:35.

[0084] The recycled polyol blend has the following characteristics: - hydroxyl value of 28 mg (KOH).g -1 , - acid number of 0.5 mg(KOH).g -1 , And - viscosity at 25°C of 6500 mPa.s. It can be implemented, as such, in a molded polyurethane foam production reaction because it has a viscosity, hydroxyl index and acid index suitable for the high-resilience mattress molding process on standard production machines.

[0085] Example 1b: Obtaining formulated polyol mixtures

[0086] The recycled polyol mixture from Example 1 b is mixed, in different proportions, with a second polyol, which is Rokopol 6010, to obtain different formulated polyols. The mass ratio of recycled polyol mixture: second polyol of the formulated polyol mixture, hereinafter referred to as 50% polyol, is 50:50. The mass ratio of recycled polyol mixture: second polyol of the formulated polyol mixture, hereinafter referred to as 75% polyol, is 75:25.

[0087] The 50% polyol has the following characteristics: - hydroxyl value of 28 mg (KOH).g -1 , - acid number of 0.25 mg(KOH).g -1 , And - viscosity at 25°C of 3000 mPa.s.

[0088] The 75% polyol has the following characteristics: - hydroxyl value of 28 mg (KOH).g -1 , - acid number of 0.4 mg(KOH).g -1 , And - viscosity at 25°C of 5000 mPa.s.

[0089] They can be implemented, as such, in a molded polyurethane foam production reaction because it has a viscosity, hydroxyl index and acid index suitable for the high-resilience mattress molding process on standard production machines.

[0090] Example 2: Production of high-resilience molded polyurethane foams from the polyols formulated in Example 1b.

[0091] Example 2a: Polyol 50%.

[0092] A rise profile of a foam obtained by mixing 57% by mass of 50% polyol, 38% by mass of an isocyanate compound (ISO 135 / 161 (BASF)), 1.9% by mass of water (blowing agent), 1% by mass of TEGOSTAB® B 8715 LF2 (surfactant), 1% by mass of diethanolamine (crosslinking agent), 0.1% by mass of DABCO NE 300 (catalyst) and 1% by mass of POLYCAT 15 (catalyst) is determined.

[0093] As highlighted by [Fig.1] and [Fig.2], this foam exhibits a foam rise profile and structure comparable to a reference foam suitable for use in a seat and obtained from Rokopol 6010, i.e. a petrochemical polyol.

[0094] It can therefore be used in a seat.

[0095] Example 2a: Polyol 75%.

[0096] The foam rise profile obtained by mixing 57% by mass of 75% polyol, 38% by mass of an isocyanate compound (ISO 135 / 161 (BASF)), 1.9% by mass of water (blowing agent), 1% by mass of TEGOSTAB® B 8715 LF2 (surfactant), 1% by mass of diethanolamine (crosslinking agent), 0.2% by mass of DABCO NE 300 (catalyst) and 0.9% by mass of POLYCAT 15 (catalyst) is determined.

[0097] As highlighted by [Fig.1] and [Fig.2], the foam obtained from the 75% polyol exhibits a foam rise profile and structure comparable to a reference foam suitable for use in a seat and obtained from Rokopol 6010, i.e. a petrochemical polyol.

[0098] It can therefore be used in a seat.

[0099] This is confirmed by [Fig.3] to [Fig.5]. Indeed, these figures highlight that the foam obtained from the 75% polyol exhibits properties of the same order of magnitude as the properties of the reference foam.

Claims

Demands

1. A process for producing a recycled molded polyurethane foam comprising the following steps: a) treating a molded polyurethane foam by acidolysis to obtain a viscous liquid, b) mixing the viscous liquid with a first polyol and a neutralizing agent to obtain a mixture of recycled polyols, and c) contacting the mixture of recycled polyols with an additive and a polyisocyanate compound to produce the recycled molded polyurethane foam, said process being characterized in that the molded polyurethane foam is a high-resilience molded polyurethane foam, and the mass ratio of viscous liquid:first polyol in the mixture of recycled polyols is between 90:10 and 10:

90.

2. A method according to claim 1 wherein the recycled molded polyurethane foam is for seating.

3. A method according to claim 1 wherein the recycled molded polyurethane foam is for a mattress, a sofa, an armrest, a seating element such as a headrest, a vehicle dashboard or a vehicle door panel.

4. A method according to any one of claims 1 to 3, wherein the viscous liquid has the following properties: - a hydroxyl value between 20 mg(KOH).g -1 and 100 mg (KOH).g -1 , - an acid value greater than 1 mg(KOH).g -1 , And - a viscosity at 25°C greater than 15,000 mPa.s.

5. A method according to any one of claims 1 to 4 wherein the first polyol is selected from alkoxylated glycerol, alkoxylated sorbitol, alkoxylated diethyl triamine, alkoxylated sucrose, polyoxypropylene glycol-based polyols and mixtures thereof.

6. A method according to any one of claims 1 to 5 wherein step b) is carried out in one or more steps.

7. A process according to any one of claims 1 to 6 wherein the recycled polyol mixture has an acid value less than or equal to 1 mg(KOH).g -1 and at least one of the following characteristics: - a viscosity at 25°C between 500 mPa.s and 15,000 mPa.s, and - a hydroxyl value between 20 mg(KOH).g -1 and 100 mg (KOH).g -1 .

8. A method according to any one of claims 1 to 7 further comprising, between step b) and step c): - a step of mixing the recycled polyol mixture with a second polyol to to obtain a mixture of formulated polyols which is then implemented in step c), the mass ratio of recycled polyol mixture:second polyol in the mixture of formulated polyols being between 1:99 and 99:

1.

9. A process according to claim 8 wherein the second polyol is selected from glycerol-initiated polyoxypropylene-polyoxyethylene glycols.

10. A process according to any one of claims 1 to 9 wherein the polyisocyanate compound is selected from m-phenylene diisocyanate, toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, hexamethylene 1,6-diisocyanate, tetramethylene 1,4-diisocyanate, cyclohexane 1,4-diisocyanate, hexahydrotoluene diisocyanate, naphthylene 1,5-diisocyanate, methoxyphenyl-2,4-diisocyanate, diphenylmethane 4,4'-diisocyanate and its isomers, biphenylene 4,4'-diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, diisocyanate of 3,3'-dimethyl-4,4'-biphenyl, 3,3'-dimethyldiphenylmethane 4,4'-diisocyanate, 4,4',4'-triphenylmethane triisocyanate, polymethylene polyphenylisocyanate, polymeric diphenylmethane diisocyanate, isophorone diisocyanate, 2,4,6-toluene triisocyanate, 4,4'-dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate,Polymethylenepolyphenyl ester of isocyanic acid and mixtures thereof.

11. A process according to any one of claims 1 to 10 wherein the mass ratio of recycled polyols mixture:polyisocyanate compound is between 1:99 and 95:

5.

12. A method according to any one of claims 1 to 11 wherein the additive is selected from a surfactant, a crosslinker, a flame retardant, a blowing agent, a release agent, an anti-hydrolysis agent, a biocide and mixtures thereof.

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