Recycling of polyol produced from molded polyurethane foam

Abstract

The present application relates to a method for producing a recycled molded polyurethane foam for seating from a used molded polyurethane foam Abstract Figure: Figure 1

Description

Title of the invention: Recycling of polyol produced from molded polyurethane foam Technical field

[0001] The present disclosure relates to the field of molded polyurethane foams for automotive seating. In particular, the present disclosure relates to the recycling of these polyol foams to form new molded polyurethane foams. Prior Art

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

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

[0004] Today, used molded polyurethane seat foams are mainly incinerated or landfilled, so they are not recycled. They therefore 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 circle of recycling these foams.

[0005] Producing, from these used foams, a polyol which has the desired properties for the production of foams for automotive seats is not obvious. Indeed, to produce a recycled molded polyurethane foam having comfort properties and meeting the requirements of automotive seats, it is necessary that The depolymerization of the polyurethane in these used foams allows the crosslinked structure of the polyurethane to be cut very precisely in order to produce small molecules comprising hydroxyl groups capable of subsequently reacting with isocyanates. It is therefore to the credit of the inventors to have found a process which meets this need. Summary

[0006] A method for producing a recycled molded polyurethane foam for a seat, in particular for an automobile seat, for an airplane seat, for a seat for furniture, more particularly for an automobile seat, is proposed, comprising the following steps: (a) acidolysis treatment of a 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, an additive and a polyisocyanate compound to produce the recycled molded polyurethane foam for seating, said process being characterized in that the molded polyurethane foam is a high resilience molded polyurethane foam for seating, in particular for automobile seating, for aircraft seating, for seating for furniture, more particularly for automobile seating, and the viscous liquid:first polyol mass ratio in the recycled polyol mixture is between 90:10 and 10:90, in particular between 80:20 and 20:80, very particularly between 50:50 and 75:25.

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

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

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

[0010] It is to the credit of the inventors to have found that step b) of the method of the invention makes it possible to solve this problem. Indeed, the inventors are of the opinion that the mixture of recycled polyols has a viscosity and an acid number suitable for step c) thanks, respectively, to the first polyol and to the neutralizing agent. In particular, the viscosity and the acid number of the mixture of recycled polyols allows the implementation of step c) in a normal industrial context, therefore without modification of conventional equipment.

[0011] Thus, thanks to steps a), b) and c), the method of the present invention creates a virtuous circle of recycling a significant quantity of used molded polyurethane foam for seats into recycled molded polyurethane foam for seats, 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 foam for seats, and to reduce the CO2 emissions from the production chain of this foam.

[0013] The method of the present invention also makes it possible to reduce and limit the volatility of the production costs of molded polyurethane foam for seats by limiting the quantity of petroleum-based polyols incorporated into this foam.

[0014] In addition, the foam produced by the process of the present invention has mechanical properties, in particular a density, a tear propagation strength ("Tear propagation Strength" according to English terminology), a compression set after compression at constant thickness ("Compression set" according to English terminology) of the same order of magnitude as an industrial molded foam produced from polyols of petrochemical origin and commonly used in automobile seats. The molded foam produced by the process of the present invention also has a reactivity, characterized by a rise profile ("Joam rise profile" according to English terminology), comparable to the rise profile of an industrial foam produced from polyols of petrochemical origin and commonly used in seats.The foam produced by the process of the present invention can therefore be used in seats, in particular for automobile seats, for aircraft seats, for seats for furniture. Furthermore, this foam does not require . modify the classic industrial process for producing molded polyurethane foam for seating.

[0015] According to another aspect, there is provided a molded polyurethane foam for a seat, in particular for an automobile seat, for an airplane seat, for a seat for furniture, more particularly for an automobile seat, which can be obtained by the method of the present invention. Brief description of the drawings

[0016] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which: Fig.l

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

[0018] [Fig.2] shows different photos of foams according to the invention and of a foam of reference. 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 residual deformation after compression at constant thickness of a foam according to the invention and a reference foam. Description of the embodiments

[0022] A method for producing a recycled molded polyurethane foam for a seat, in particular for an automobile seat, for an airplane seat, for a seat for furniture, more particularly for an automobile seat, comprising the following steps: (a) acidolysis treatment of a 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, an additive and a polyisocyanate compound to produce the recycled molded polyurethane foam for seating, said process being characterized in that the molded polyurethane foam is a high resilience molded polyurethane foam for seating, in particular for automobile seating, for aircraft seating, for seating for furniture, more particularly for automobile seating, and the viscous liquid:first polyol mass ratio in the recycled polyol mixture is between 90:10 and 10:90, in particular between 80:20 and 20:80, very particularly 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", designates a compound with a three-dimensional cellular structure of the expanded type.

[0024] For the purposes of the present invention, the term "molded seat foam" designates 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 from this production, and mixtures thereof. Typically, the molded seat foam may be End of Life Vehicle foam as defined in European Directive 2000 / 53 / EC of September 18, 2000.

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

[0026] Step a) of treatment by acidolysis is a conventional step known to those skilled in the art. It is described for example in POLIMERY 2018, 63, nr 3 234-238. Those skilled in the art will know how to implement it to obtain the viscous liquid, in particular a viscous liquid having the following properties: - a hydroxyl number between 20 mg(KOH).g 1 and 100 mg(KOH).g *, more particularly between 25 mg(KOH).g 1 and 60 mg(KOH).g *, - an acid number greater than 1 mg(KOH).g *, in particular between 5 mg(KOH).g 1 and 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 number" (also noted as "OH number") represents the quantity of potassium hydroxide in mg corresponding to the number of hydroxyl groups present in 1 g of material.

[0028] Advantageously, the hydroxyl index range of the viscous liquid allows the production of a crosslinked three-dimensional network giving the foam, among other things, mechanical properties suitable for its use in an automobile seat. On the other hand, the high viscosity of the viscous liquid disrupts its pumping and injection into the mold allowing the production of the molded polyurethane foam. In addition, the produced molded polyurethane foam is destabilized by the high viscosity and high acid number of the viscous liquid.

[0029] For the purposes of the present invention, "acid number" means the amount of residual acidic material in the polyol. It is reported in terms of 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 the Brookfield viscosity and / or the viscosity measured by a cone-plate viscometer at 25°C.

[0031] The first polyol is a petrochemical, recycled or biosourced polyol allowing the production of polyols of variable functionality. The first polyol may, for example, be chosen from alkoxylated glycerol, alkoxylated sorbitol, alkoxylated diethyl triamine, alkoxylated sucrose, polyols based on polyoxypropylene glycol and mixtures thereof, in particular from polyols based on polyoxypropylene glycol and mixtures thereof.

[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 amino compound or an alcohol or mixtures thereof, in particular a basic inorganic salt, an amino compound or mixtures thereof.

[0034] Typically the basic inorganic salt may be sodium hydroxide, potassium hydroxide, calcium chloride, calcium carbonate, sodium bicarbonate and mixtures thereof.

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

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

[0037] According to one embodiment, the mixing step b) 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 makes it possible to adjust the properties of the mixture of recycled polyols at will depending on the 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 site of production of the viscous liquid in order to reduce its viscosity and facilitate its transport to the site of production of recycled molded polyurethane foam. At this second production site, step b) can be carried out again to obtain the recycled polyol blend. This limits the costs associated with transporting the first polyol.

[0039] The mixture of recycled polyols may have an acid number less than or equal to 1 mg(KOH).g *, 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 number between 20 mg(KOH).g 1 and 100 mg(KOH).g *, in particular between 25 mg(KOH).g 1 and 60 mg(KOH).g *.

[0040] These characteristics depend on the properties of the viscous liquid, in particular its viscosity and acid number, the nature of the first polyol and the viscous liquid:first polyol mass ratio described above. Those skilled in the art will know how to adjust these parameters to obtain the mixture of recycled polyols which may comprise at least one, in particular two, and particularly all of these characteristics.

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

[0042] According to one embodiment, the method of the present invention may further comprise, between step b) and step c): - a step of mixing the mixture of recycled polyols with a second polyol to obtain a mixture of formulated polyols which is then used in step c), the mass ratio of mixture of recycled polyols:second polyol in the mixture of formulated polyols being between 1:99 and 99:1, in particular between 20:80 and 80:20, very particularly 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 may be chosen from polyols based on glycerol-initiated polyoxypropylene-polyoxyethylene glycols (triols).

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

[0047] The mixture of formulated polyols may have an acid number of less than 1 mg(K0H).g *, in particular less than or equal to 0.5 mg(K0H).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 number between 20 mg(K0H).g 1 and 100 mg(KOH).g *, in particular between 25 mg(K0H).g 1 and 60 mg(KOH).g *.

[0048] These characteristics depend on the properties of the mixture of recycled polyols, the nature of the second polyol and the mass ratio of first polyol:second polyol described above. Those skilled in the art will know how to adjust these parameters to obtain a mixture of formulated polyols which can comprise at least one, in particular two, and particularly all of these characteristics.

[0049] Typically, the polyisocyanate compound may be 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, 4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate, 4,4'-3,3'-dimethyldiphenylmethane diisocyanate, 4,4',4"-triphenyl methane 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, a , polymethylene polyphenylisocyanate, polymeric diphenylmethane diisocyanate, isophorone diisocyanate, polymethylenepolyphenyl ester of isocyanic acid and mixtures thereof, especially among 4,4'-diphenylmethane diisocyanate and its isomers, polymethylene polyphenylisocyanate, polymeric diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, polymethylenepolyphenyl ester of isocyanic acid and mixtures thereof, especially still polymeric diphenylmethane diisocyanate.

[0050] The mass ratio of recycled polyol mixture:polyisocyanate compound may be between 1:99 and 95:5, in particular between 20:80 and 80:20, most particularly between 55:50 and 75:25. Those 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 makes it possible to modify and / or improve the properties of the high resilience molded polyurethane foam produced.

[0052] Typically the additive may be chosen from a surfactant, a crosslinker, a flame retardant, a swelling agent, a mold release agent, an antihydrolysis agent, a biocide and mixtures thereof, in particular chosen from a surfactant, a crosslinker, a flame retardant, a swelling agent and mixtures thereof, more particularly being a mixture of surfactant, swelling agent and crosslinker.

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

[0054] For the purposes of the present invention, "crosslinker" designates a compound which generates the formation of one or more three-dimensional networks in the high resilience molded polyurethane foam. The crosslinker may be chosen from glycerol, diethanolamine, triethanolamine, glycols with a molecular mass of less than 1000 and a functionality of greater than or equal to 3 and mixtures thereof, in particular being diethanolamine.

[0055] For the purposes of the present invention, "blowing agent" means a compound inducing, by chemical and / or physical action, an expansion of a composition during a foaming step. Typically, the chemical blowing agent is chosen from water, formic acid, phthalic anhydride and acetic acid. The physical blowing agent may be chosen from pentane and pentane isomers, hydrocarbons, hydrofluorocarbons, hydrochlorofluoroolefins, hydrofluoroolefins (HFOs), ethers and mixtures thereof. Methylal may be mentioned as 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 or formic acid / pentane isomer or water / hydrofluoroolefins or pentane isomer / methylal / water or water / methylal.

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

[0057] For the purposes of the present invention, "surfactant" designates an agent allowing the physical stability of the polymer matrix during the progress of the reactions, in particular by anti-coalescent stabilization during the polymerization. Typically, the surfactant is chosen from any of the silicone glycol copolymers, 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 polysiloxane polyoxyalkylene block 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 mixture (hybrid) or in a solvent or mixture of solvents.

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

[0060] The mixture of recycled polyols, the additive and the polyisocyanate compound can be premixed 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, the reaction step c) can be carried out at a temperature between 30°C and 100°C, in particular between 40°C and 80°C, most particularly between 50°C and 65°C.

[0062] A catalyst may be used to accelerate the kinetics of the reaction 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 quantity of catalyst used in the process for manufacturing a polyurethane foam of the invention depends on the compounds used in said process. Those skilled in the art will know how to adapt this quantity.

[0065] Typically, the catalyst may be chosen from catalysts known to catalyze expansion (water-isocyanate) and gelation (polyol-isocyanate) reactions. N,N,N'-trimethyl-N'-hydroxyethyl-bisaminoethylether, bis (2-dimethyl-aminoethyl) ether, 1,3-bis[3-(dimethylamino)propyl]urea, 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-l,3-propanediamine (DABCO NE300), 1,4-diazabicyclooctane (TEGOAMIN 33), N'-[3-(dimethylamino)propyl]-N,N-dimethylpropane-l,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 method may further comprise, before step a) of treatment by acidolysis, a step of grinding the molded polyurethane foam to obtain particles having a diameter of between 1 mm and 20 mm, in particular between 3 mm and 10 mm, very particularly between 4 mm and 6 mm, which are then implemented in step a) of treatment by acidolysis.

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

[0068] The use of particles having a diameter in these ranges makes it possible to facilitate and accelerate the depolymerization of the molded polyurethane foam.

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

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

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

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

[0073] The amine compounds of the viscous liquid can alter the implementation of step c) of the process of the present invention.

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

[0075] According to another aspect, there is provided a molded polyurethane foam for a seat, in particular for an automobile seat, for an airplane seat, for a seat for furniture, more particularly for an automobile seat, which can be obtained by the method of the present invention.

[0076] Advantageously, this molded polyurethane foam for a seat has properties, in particular a density, resistance to tear propagation, and residual deformation after compression at constant thickness of the same order of magnitude as an industrial polyurethane foam produced from polyols of petrochemical origin and commonly used in automobile seats. This polyurethane foam can therefore be used in an automobile seat. Examples

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

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

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

[0080] Example 1a: Obtaining the mixture of recycled polyols

[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 number of 30 mg(KOH).g *, - acid number of 8 mg(KOH).g *, and - viscosity at 25°C of 35,000 mPa.s. It cannot therefore be used as such in a reaction to produce molded polyurethane foam. Indeed, its high viscosity disrupts its pumping and injection into the mold, allowing the production of molded polyurethane foam. In addition, the molded polyurethane foam produced would be destabilized by its high viscosity and acid number.

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

[0084] The mixture of recycled polyols has the following characteristics: - hydroxyl number of 28 mg(KOH).g *, - acid number of 0.5 mg(KOH).g *, and - viscosity at 25°C of 6500 mPa.s. It can be used, as such, in a reaction for producing a molded polyurethane foam because it has a viscosity, a hydroxyl number and an acid number suitable for the molding process of high resilience padding on standard production machines.

[0085] Example 1b: Obtaining the _ formulated polyol mixtures

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

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

[0088] The 75% polyol has the following characteristics: - hydroxyl index of 28 mg(K0H).g *, - acid number of 0.4 mg(K0H).g *, and - viscosity at 25°C of 5000 mPa.s.

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

[0090] Example 2: P reduction of high resilience molded polyurethane foams _ from the polyols _ formulated from 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 (crosslinker), 0.1% by mass of DABCO NE 300 (catalyst) and 1% by mass of POLYCAT 15 (catalyst) is determined.

[0093] As highlighted by [Fig.l] and [Fig.2], this foam has a foam rise profile and a 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 (crosslinker), 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.l] and [Fig.2], the foam obtained from the 75% polyol has a foam rise profile and a 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 show that the foam obtained from the 75% polyol has properties of the same order of magnitude as the properties of the reference foam.

Claims

Claims

1. A method for producing a recycled molded polyurethane foam for seating comprising the following steps: a) acidolysis treatment of a molded polyurethane foam to obtain a viscous liquid, b) mixing the viscous liquid with a first polyol and a neutralizing agent to obtain a recycled polyol mixture, and c) contacting the recycled polyol mixture, an additive and a polyisocyanate compound to produce the recycled molded polyurethane foam for seating, said method being characterized in that the molded polyurethane foam is a high resilience molded polyurethane foam for seating, the viscous liquid:first polyol mass ratio in the recycled polyol mixture is between 90:10 and 10:90, wherein the viscous liquid has the following properties: - a hydroxyl number between 20 mg(KOH).g 1 and 100 mg(KOH).g *, - an acid number greater than 1 mg(KOH).g *, and - a viscosity at 25°C greater than 15,000 mPa.s.

2. Process according to claim 1 in which the mixture of recycled polyols has an acid number less than or equal to 1 mg(KOH).g 1 and at least one of the following characteristics: - a viscosity at 25°C of between 500 mPa.s and 15,000 mPa.s, and - a hydroxyl number of between 20 mg(KOH).g 1 and 100 mg(KOH).g *.

3. The method of claim 1 or 2 wherein the first polyol is selected from alkoxylated glycerol, alkoxylated sorbitol, alkoxylated diethyl triamine, alkoxylated sucrose, polyoxypropylene glycol-based polyols and mixtures thereof.

4. Method according to any one of claims 1 to 3 in which step b) is carried out in 1 or more times.

5. Method according to any one of claims 1 to 4 further comprising, between step b) and step c): - a step of mixing the mixture of recycled polyols with a second polyol to obtain a mixture of formulated polyols which is then implemented in step c),

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9. the mass ratio of recycled polyol mixture:second polyol in the formulated polyol mixture being between 1:99 and 99:

1. Method according to claim 5 in which the second polyol is chosen from polyols based on polyoxypropylene-polyoxyethylene glycols initiated with glycerol. A process according to any one of claims 1 to 6 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, 4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate, 4,4'-3,3'-dimethyldiphenylmethane diisocyanate, 4,4',4"-triphenyl methane triisocyanate, polymethylene polyphenylisocyanate, polymeric diphenylmethane diisocyanate, isophorone diisocyanate, 2,4,6-toluene triisocyanate, 4,4'-dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate, isocyanic acid polymethylenepolyphenyl ester and mixtures thereof. Process according to any one of claims 1 to 7 in which the mass ratio of recycled polyol mixture:polyisocyanate compound is between 1:99 and 95:

5. A method according to any one of claims 1 to 8 wherein the additive is chosen from a surfactant, a crosslinker, a flame retardant, a swelling agent, a mold release agent, an anti-hydrolysis agent, a biocide and mixtures thereof.

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