Mixture and method based on recovered components

Abstract

Recovery component-based mixtures, methods and polyurethanes prepared from reaction systems comprising isocyanates and the recovery component-based mixtures are provided.

Description

Technical Field

[0001] The present disclosure relates to recycled content-based mixtures, in particular to recycled content-based mixtures from recycled synthetic leather and methods of making the recycled content-based mixtures. Background Art

[0002] Synthetic leather based on polyurethane chemistry has been widely used in many scenarios, including vehicle interiors, furniture, bags, packaging, and clothing. Traditionally, many synthetic leathers have a layered structure and contain a fabric layer made of polyamide, poly(ethylene terephthalate) or other synthetic fibers in addition to a polyurethane-based top layer and base layer.

[0003] End of life, post-industrial or post-consumer synthetic leather products pose a threat to the environment because these composite materials are made from fossil resources and are difficult to degrade. It has long been desired to recycle synthetic leather products. Conventional recycling technologies such as heat treatment or pyrolysis have difficulty converting finished leather into valuable and reusable products. At the same time, it remains a challenge to effectively mechanically separate the polyurethane resin from the fabric in synthetic leather. Summary of the invention

[0004] According to one aspect of the present disclosure, a mixture based on recycled components is provided, wherein the mixture based on recycled components comprises a hydroxyl-terminated copolyester, which comprises a C4 to C12 dicarboxylic acid structure represented by Formula 3 and a diol structure represented by Formula 3, wherein Q is a C2 to C10 alkylene group, and R is a C2 to C20 alkylene group.

[0005]

[0006] At least one of: a dispersed polyurethane or polyurea; and a hydroxyl terminated urethane or urea,

[0007] The mixture based on recycled components contains 1.0 wt % to 20.0 wt % of terephthalic acid structural units, calculated as C6H4(COOH)2 based on quantitative nuclear magnetic resonance measurement.

[0008] According to another aspect of the present disclosure, there is provided a method comprising: (a) dividing synthetic leather into a plurality of fragments; (b) mixing at least a portion of the fragments with a degradation agent to form a reaction mixture; (c) heating the reaction mixture at a temperature of 180° C. to 260° C.; and (d) obtaining a recycled component-based mixture from the heated reaction mixture, wherein the synthetic leather comprises a fabric layer of polyethylene terephthalate, a base layer and a top layer, at least one of the base layer and the top layer is made of polyurethane, and the degradation agent comprises a polyester polyol.

[0009] According to another aspect of the present disclosure, there is provided a polyurethane prepared from a reaction system comprising an isocyanate and a recycled component-based mixture.

[0010] The method disclosed herein can be used to process synthetic leather. In the past, the sorting, physical separation and recycling of synthetic leather consumed a lot of labor and energy. The method is simple and easy to perform. According to the method, post-production synthetic leather and post-consumer synthetic leather can be recycled without mechanical stratification, saving a lot of labor and energy. Since no catalyst or other reagents that may cause the urethane bond in the polyurethane to break are used in the disclosure, the urethane structure in the recycled synthetic leather is retained, and the mixture based on the recycled components produced by the method contains low amounts or no amine compounds, which are often present in high concentrations in chemical recycling methods (such as hydrolysis and alcoholysis). At the same time, the viscosity of the mixture based on the recycled components produced is appropriate and can be handled by conventional physical and chemical means. In addition, the mixture based on the recycled components obtained by the method can be directly used as a raw material for producing new polymers (such as polyurethane). The polyurethane product prepared from the mixture based on the recycled components has good properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 An exemplary flow chart of a method for preparing a recycled component based mixture according to one embodiment is shown. DETAILED DESCRIPTION

[0012] The term "hydroxyl number" refers to the mass (in milligrams) of potassium hydroxide (KOH) required to neutralize the acetic acid absorbed when one gram of a polyol or a blend of polyols is acetylated. The hydroxyl number is determined according to Deutsches Institut für Normung (DIN) 53240 in 2012 and is expressed in mgKOH / g. For mixtures such as a combination of several polyols, the total hydroxyl number is used, which can be calculated as a weighted average of the hydroxyl numbers of its individual components.

[0013] The term "acid value" refers to the mass (in milligrams) of potassium hydroxide (KOH) required to neutralize the acidic groups of one gram of a polyol or a blend of polyols. Acid value is determined by 2020 ASTM D4662 and is measured in mgKOH / g.

[0014] The term "fragments" refers to objects whose size, porosity, density or morphology has been changed by physical or chemical means, and may include blocks, particles or powders. The ways to obtain fragments from synthetic leather include manual disassembly, mechanical cutting, shredding or melt granulation.

[0015] The term "functionality" of a polyol refers to the number of hydroxyl groups per polyol molecule. The functionality of a blend of several polyols refers to the molar average of the functionalities of all the polyol components.

[0016] The term "isocyanate index" or "NCO index" of a polyurethane system refers to the ratio of the number of NCO groups present in the polyurethane system to the number of isocyanate-reactive hydrogen atoms, given as a percentage:

[0017]

[0018] [NCO] is the number of NCO groups.

[0019] [Isocyanate-reactive hydrogens] is the number of isocyanate-reactive hydrogen atoms.

[0020] In other words, the isocyanate index expresses the percentage of isocyanate actually used in a formulation relative to the theoretically required amount of isocyanate to react with the isocyanate-reactive hydrogen used in the formulation.

[0021] The mixture based on recycled components in the present disclosure is obtained by processing polyurethane-based synthetic leather, and therefore contains nitrogen derived from isocyanate, which is present in urethane bonds or urea bonds. It can be determined by quantitative analysis methods such as quantitative nuclear magnetic resonance. For example, when determining the nitrogen content derived from diphenylmethane diisocyanate, the methylene content can be determined by nuclear magnetic resonance method first, and then the nitrogen content can be obtained based on the ratio of nitrogen to methylene.

[0022] As used in the present disclosure, the term "C2 to C10 alkylene" means a hydrocarbon diradical having 2 to 10 carbon atoms, wherein each hydrocarbon diradical is independently aromatic (6 carbon atoms or more) or non-aromatic, saturated or unsaturated, linear or branched, cyclic (including monocyclic and polycyclic, fused and non-fused polycyclic, including bicyclic; 3 carbon atoms or more) or non-cyclic, or a combination of two or more thereof; and each hydrocarbon diradical is independently the same as or different from another hydrocarbon diradical, and is independently unsubstituted or substituted with one or more substituents.

[0023] As used in the present disclosure, the term "C2 to C20 alkylene" means a hydrocarbon diradical having 2 to 20 carbon atoms, wherein each hydrocarbon diradical is independently aromatic (6 carbon atoms or more) or non-aromatic, saturated or unsaturated, linear or branched, cyclic (including monocyclic and polycyclic, fused and non-fused polycyclic, including bicyclic; 3 carbon atoms or more) or non-cyclic, or a combination of two or more thereof; and each hydrocarbon diradical is independently the same as or different from another hydrocarbon diradical, and is independently unsubstituted or substituted with one or more substituents.

[0024] The source of the alkylene group in the present disclosure is not particularly limited, for example, it can be derived from aliphatic hydrocarbons or aromatic hydrocarbons, saturated hydrocarbons or unsaturated hydrocarbons, straight-chain hydrocarbons, branched-chain hydrocarbons or cyclic hydrocarbons, hydrocarbons or heterohydrocarbons, etc. From the perspective of saturation, for example, it can be derived from alkanes, alkenes, alkynes, dienes, etc.; for cyclic hydrocarbons, for example, it can be derived from alicyclic hydrocarbons or aromatic hydrocarbons, monocyclic hydrocarbons or polycyclic hydrocarbons; for heterocyclic hydrocarbons, for example, it can be derived from alicyclic heterocyclic hydrocarbons or aromatic heterocyclic hydrocarbons.

[0025] Alkylene groups based on alkane are also called alkylene groups. Common alkylene groups include, but are not limited to, methylene, 1,2-ethylene, 1,3-propylene, 1,2-propylene, isopropylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene and the like.

[0026] The alkylene group based on unsaturated aliphatic hydrocarbon includes any basic unit such as —CH═CH—, —C≡C—, and the like.

[0027] For the cycloalkylene group, the positions of the two hydrogen atoms lost are not particularly limited, as long as they are not connected to the same carbon atom at the same time. When connected to the same carbon atom, the cyclic structure exists as a substituent of the carbon atom. Alicyclic hydrocarbons lose two hydrogen atoms on the same ring to form alicyclic hydrocarbon groups. Aromatic hydrocarbons lose two hydrogen atoms on the same aromatic ring to form arylene groups, such as p-phenylene, m-phenylene, and o-phenylene in phenylene when the two hydrogen atoms lost by aromatic hydrocarbons are located on the aromatic ring and one on its aliphatic hydrocarbon group.

[0028] The alkylene group may or may not contain substituents or side groups, including but not limited to linear, branched or cyclic structures.

[0029] In the absence of special definition, the two positions of the alkylene group connecting other groups are not particularly limited. For example, phenylene can include p-phenylene, o-phenylene, and m-phenylene. For example, propylene can include 1,2-propylene, 1,3-propylene, isopropylene, and the like.

[0030] The term "polyol" refers to an organic compound having two or more hydroxyl (-OH) groups attached to different carbon atoms of the organic compound.

[0031] Unless indicated otherwise, temperature refers to room temperature and pressure refers to ambient pressure.

[0032] According to the present disclosure, there is provided a recycled content-based mixture, the recycled content-based mixture comprising:

[0033] A hydroxyl-terminated copolyester comprising a C4 to C12 dicarboxylic acid structure as represented by Formula 5 and a diol structure as represented by Formula 6, wherein Q is a C2 to C10 alkylene group, R is a C2 to C20 alkylene group,

[0034]

[0035] At least one of the following:

[0036] Dispersed polyurethanes or polyureas; and

[0037] Hydroxyl terminated carbamate or urea,

[0038] The mixture based on recycled components contains 1.0 wt % to 20.0 wt % of terephthalic acid structural units, expressed as C6H4(COOH)2, calculated based on quantitative nuclear magnetic resonance measurements.

[0039] The terephthalic acid structural unit exists in the polyester polyol in the form of terephthalate in the mixture. The polyester polyol is one of the products formed by reactions such as transesterification of synthetic leather.

[0040] Preferably, the hydroxyl-terminated copolyester further comprises a triol-based structure derived from glycerol, trimethylolpropane or pentaerythritol, as represented by Formulas 7 to 9, respectively.

[0041]

[0042] Preferably, the recycled content based mixture comprises hydroxyl terminated oligomeric polyethylene terephthalate. The hydroxyl terminated oligomeric polyethylene terephthalate structure can be represented by Formula 10, wherein n is a positive integer.

[0043]

[0044] Preferably, the mixture based on recycled components contains less than 0.3% by weight of diamine based on the total weight of the mixture based on recycled components; more preferably, it contains less than 0.06% by weight of diamine, which is determined according to gas chromatography mass spectrometry (GCMS). More preferably, the diamine is selected from toluenediamine, methylenedianiline, naphthalenediamine, isophoronediamine, hexamethylenediamine, methylenebis(cyclohexylamine) and any combination thereof. The technician understands that the presence or amount of diamine can also be detected or measured via other characterization methods such as high performance liquid chromatography (HPLC), proton nuclear magnetic resonance, carbon-13 nuclear magnetic resonance or Fourier transform infrared spectroscopy (FTIR). Due to the extremely small amount present, it is not necessary to use acid or organic anhydride to neutralize the diamine.

[0045] The mixture based on the recycled content has a total hydroxyl value of preferably 20 to 250 mgKOH / g, more preferably 40 to 120 mgKOH / g, further preferably 40 to 100 mgKOH / g.

[0046] Preferably, the recycled content-based mixture further comprises a polyether polyol having a number average molecular weight of 1,000 to 10,000 g / mol.

[0047] Preferably, the mixture further comprises from 0.01 wt. % to 1.50 wt. % of nitrogen from isocyanates based on recycled content, the nitrogen from isocyanates being present in urethane bonds and / or urea bonds, calculated based on quantitative nuclear magnetic resonance measurements.

[0048] Preferably, the mixture based on recycled content has an acid value of 0 to 10.0 mgKOH / g. More preferably, the mixture based on recycled content has an acid value of 0 to 4.0 mgKOH / g.

[0049] Figure 1 An exemplary flow chart of a method is shown. The method can be used to prepare a mixture based on recycled components or to produce polyurethane. Although the flow chart depicts a specific order, the order can be changed without departing from the scope of the present disclosure. For example, some of the operations depicted can be performed in parallel or in a different order without substantially affecting the function. In other examples, different components of the example device or system implementing the routine can perform functions substantially simultaneously or in a specific order.

[0050] At the end of the process, a mixture based on recovered components is obtained.

[0051] According to some examples, the method includes, at block 102 , segmenting the synthetic leather into a plurality of pieces.

[0052] The synthetic leather comprises a fabric layer, a base layer and a top layer of poly(ethylene terephthalate) in order. Two surfaces of the base layer are in contact with the fabric layer and the top layer, respectively. At least one of the base layer and the top layer is made of polyurethane. The base layer can be dense or foamed. The top layer is usually made of water-based or solvent-based polyurethane / polyurea resin. In some embodiments, the synthetic leather comprises a four-layer structure, which, in addition to the top layer, the base layer and the fabric layer in order, also comprises a layer of soft foam, which is in direct contact with the fabric layer or attached to the fabric layer through an adhesive (e.g., a polyurethane-based adhesive). The soft foam may be based on a polyurethane chemical structure. In other embodiments, the synthetic leather comprises a five-layer structure, in addition to the top layer, the base layer, the fabric layer and the soft foam in order, the soft foam in the synthetic leather is in direct contact with a non-woven fabric layer through a surface not in contact with the fabric layer or attached through an adhesive. The non-woven fabric layer may be based on poly(ethylene terephthalate), polylactic acid or other thermoplastic polymers. The synthetic leather may be post-production synthetic leather, post-consumer synthetic leather, or a combination of both.

[0053] Preferably, the weight ratio of polyurethane to poly(ethylene terephthalate) in the synthetic leather is 20:80 to 70:30.

[0054] Preferably, the fabric layer and the base layer are substantially not separated in the plurality of pieces obtained at block 102. The step of dividing the synthetic leather can be achieved using mechanical comminution equipment such as a shredder, a cutting machine, a knife roll, a roller crusher, a shredder, etc. The dividing step can be simple and does not involve complex machines or time-consuming processes.

[0055] Preferably, the fragments have an average size of no more than 10 x 10 cm.

[0056] According to some examples, the method includes mixing at least a portion of the fragments with a degradation agent to form a reaction mixture at block 104. The degradation agent includes a polyester polyol.

[0057] The polyester polyol in the degradation agent comprises a polyester terminated with two or more hydroxy groups and based on a C4 to C12 dicarboxylic acid.

[0058] The polyester polyol may be obtained by polymerizing a reaction system including a C4 to C12 dicarboxylic acid represented by Formula 11 and a diol represented by Formula 12.

[0059]

[0060] Wherein, Q is a C2 to C10 alkylene group, and R is a C2 to C20 alkylene group.

[0061] The above reaction system may further comprise other components, for example, triols such as glycerol and trimethylolpropane and / or tetraols such as pentaerythritol.

[0062] According to the present disclosure, the degradation agent may react with both poly(ethylene terephthalate) and / or polyurethane.

[0063] For each kilogram of debris at box 104, preferably, 0.5 to 100 kilograms of degradation agent are added, for example, 0.5, 0.6, 0.8, 1.0, 1.2, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 6.0, 8.0, 10.0, 12.0, 15.0, 20.0, 25.0, 30.0, 40.0, 50.0, 60.0, 70.0, 80.0, 90.0 or 100.0 kilograms of degradation agent may be added. More preferably, 1.2 to 10 kilograms of degradation agent are added at box 104. Further preferably, 1.5 to 3 kilograms of degradation agent are added at box 104.

[0064] For each kilogram of fragments at box 104, preferably, the weight of polyester polyol present in the degradation agent is in the range of 0.5 to 30 kilograms, for example, the weight of polyester polyol can be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 12.0, 14.0, 16.0, 20.0, 24.0 or 30.0 kilograms. More preferably, the weight of polyester polyol is in the range of 1 to 8 kilograms. Further preferably, the weight of polyester polyol is in the range of 1.2 to 2 kilograms.

[0065] Preferably, the polyester polyol has a number average molecular weight of 300 to 6,000 g / mol, preferably 500 to 3,000 g / mol, more preferably 1,000 to 2,500 g / mol. For example, the polyester polyol as a degradation agent has 300 g / mol, 500 g / mol, 750 g / mol, 1,000 g / mol, 1,500 g / mol, 2,000 g / mol, 2,500 g / mol, 3,000 g / mol, 4,000 g / mol, 5,000 g / mol, 6,000 g / mol or any molecular weight between these values. The polyester polyol with a relatively low molecular weight has sufficient reactivity in the ester exchange reaction with the ester bond in poly (ethylene terephthalate) and / or polyurethane, and does not react with the urethane bond in the polyurethane. The ester exchange reaction does not require the additional addition of a catalyst and can occur only under certain temperature conditions (such as 180-260 ° C).

[0066] The polyester polyol suitable for use as a degradation agent can be prepared by condensing an organic diacid with a polyol. The organic diacid has 4 to 12 carbon atoms, preferably a C4 to C10 saturated diacid or a C8 to C12 aromatic diacid. The polyol is preferably a diol with 2 to 20 carbon atoms or a higher alcohol with 3 to 20 carbon atoms, and is particularly preferably a diol or triol of an aliphatic, cycloalkane, and aromatic hydrocarbon with 2 to 14 carbon atoms.

[0067] The weight content of the polyester polyol in the degradation agent is preferably 10% to 100%; more preferably 20% to 100%; further preferably 30% to 100%; further preferably 40% to 100%.

[0068] Preferably, at block 104, the degradation agent further includes a polyether polyol having a number average molecular weight of 1,000 to 10,000 g / mol. At this time, the polyether polyol can be used as a dispersion medium to reduce the viscosity of the product after the reaction.

[0069] When the degradation agent includes polyester polyol and polyether polyol having a number average molecular weight of 1,000 to 10,000 g / mol, the polyester polyol and the polyether polyol may be mixed with the fragments simultaneously as components of the degradation agent or may be mixed with the fragments separately.

[0070] For example, in some embodiments, polyester polyols are first mixed with polyether polyols to obtain a uniform degradation agent, which is then mixed with the fragments.

[0071] Alternatively, the polyester polyol is first mixed with the chips and then the polyether polyol is added. The interval between the two steps can be 15, 30, 60, 90, 120, 150, 180, 240, 300 or 360 minutes. During this interval, the mixed system of chips and polyester polyol can be heated to, for example, 180, 190, 200, 210, 220, 230, 240, 250 or 260°C.

[0072] Alternatively, the polyether polyol is first mixed with the chips and then the polyester polyol is added. The interval between the two steps can be 15, 30, 60, 90, 120, 150, 180, 240, 300 or 360 minutes. During this interval, the mixed system of chips and polyether polyol can be heated to, for example, 180, 190, 200, 210, 220, 230, 240, 250 or 260°C.

[0073] The step at box 104 can be performed in a reactor equipped with a mechanical stirrer. The preferred stirring speed is 50 to 500 rpm.

[0074] According to some examples, the method includes heating the reaction mixture at a temperature of 180° C. to 260° C. at block 106. Preferably, the reaction mixture is heated at a temperature of 180° C. to 250° C. More preferably, the reaction mixture is heated at a temperature of 210° C. to 250° C.

[0075] The above temperature can accelerate the reaction between the synthetic leather and the degradation agent. In addition, since the reaction mixture contains a small amount of ethylene glycol as a transesterification product of polyethylene terephthalate, the temperature of 180° C. to 260° C. is conducive to the removal of ethylene glycol. In addition, the elevated temperature can promote the melting and dispersion of polyurethane or polyurea into the degradation agent.

[0076] Preferably, the heating is accompanied by stirring at block 106. Stirring can be achieved using equipment known to the skilled person, such as a stirring paddle, a magnetic stirrer, or a bubbler.

[0077] Preferably, at block 106, the reaction mixture is heated for at least 1 hour; more preferably, the reaction mixture is heated for 1 to 48 hours; and even more preferably, the reaction mixture is heated for 2 to 24 hours. For example, the reaction mixture may be heated for 1, 2, 3, 4, 6, 8, 12, 15, 18, 24, 30, 36, or 48 hours.

[0078] Preferably, the reaction mixture is heated in a protective atmosphere at block 106. The protective atmosphere may be an atmosphere of nitrogen, carbon dioxide, argon, or any mixture thereof.

[0079] At block 106, the reaction mixture is heated in the absence of a catalyst. Catalysts include alkali metal hydroxides, alkaline earth metal hydroxides, organometallic catalysts, alcohol amine catalysts, and tertiary amine catalysts. In the absence of a catalyst, heating the reaction mixture generates no or very little diamine. Even if present, the diamine does not need to be neutralized with an acid or an organic anhydride.

[0080] The presence of alkali metal hydroxides or alkaline earth metal hydroxides can promote the decomposition of carbamates, which releases unpleasant and harmful diamines. In addition, the reaction system without such hydroxides will not have excessively high alkalinity, thus reducing safety hazards and operational complexity.

[0081] Organic metal catalysts include organic titanium catalysts, organic tin catalysts and organic bismuth catalysts. Organic titanium catalysts include titanates. Organic tin catalysts include dibutyltin dilaurate, stannous octoate, dibutyltin didodecylsulfide and dibutyltin diacetate. Organic bismuth catalysts include bismuth octoate and bismuth laurate.

[0082] The tertiary amine organic catalyst includes triethylenediamine, N-methylmorpholine, dimethylaminopropylamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-isopropyldiethanolamine, N-n-butyldiethanolamine, dipropanolamine, N-methyldipropanolamine, N-ethyldipropanolamine or N-isopropyldipropanolamine.

[0083] The presence of a catalyst can promote carbamate cleavage, which is an undesirable reaction. No catalyst is added at frame 106, resulting in the final recovered component being free of organometallic compound catalysts, alcohol amine catalysts and tertiary amine catalysts, which is conducive to stable storage. At the same time, when the mixture based on the recovered component is used again to synthesize new polyurethane, some potential side reactions are also avoided. According to some examples, the method includes obtaining a mixture based on the recovered component from the heated reaction mixture at frame 108.

[0084] Box 108 may be performed when or after all visible solids or particulates disappear. Alternatively, box 108 may be performed when or after the heated reaction mixture has a constant hydroxyl value and / or acid value and viscosity over a period of, for example, 1 hour, 2 hours, or 30 minutes.

[0085] According to some examples, the method further includes producing polyurethane by reacting the mixture based on the recycled components with polyisocyanates at frame 110. The polyurethane can be a thermoplastic polyurethane, a foamed polyurethane or a cross-linked / compacted polyurethane. Exemplary polyisocyanates are known in the art, including aromatic, aliphatic and alicyclic polyisocyanates, whose molecules contain two or more isocyanate groups. The reaction can further involve a chain extender such as butanediol or propylene glycol, a cross-linking agent such as glycerol or other triols, a catalyst (including but not limited to a metal catalyst and an amine catalyst), etc.

[0086] pass Figure 1 The exemplary method described in the above can obtain a mixture based on recycled components. In some embodiments, the mixture has a viscosity of about 1.10 to 1.30 g / cm 3 The inventors have found that the recycled content-based mixture unexpectedly contains only a relatively small amount of diamines, which are usually released in large quantities after alcoholysis of polyurethane or polyurea. Therefore, the obtained recycled content-based mixture is less harmful to the environment or health. Alternatively, by Figure 1 The method can obtain polyurethane, which can be used as a material in various applications and has a low content of diamine.

[0087] According to the present disclosure, a polyurethane prepared by a reaction system comprising an isocyanate and a mixture based on recycled components is further provided. The mixture based on recycled components (due to the presence of isocyanate reactive functional groups) can react with isocyanates such as diisocyanates or polyisocyanates to form polyurethane. The polyurethane can be dense or foamed, depending on whether there is a blowing agent in the reaction system. Polyurethane can be used in various applications, including construction, transportation, consumer electronics, electrical appliances, clothing, accessories, bags and packaging, etc. Specifically, polyurethane can be used to produce a base layer and / or top layer in a synthetic leather product.

[0088] Examples

[0089] The following examples are intended to illustrate the present disclosure.

[0090] The materials used in the examples are as follows:

[0091] Post-consumer synthetic leather 1 comprises three layers, a fabric layer of polyethylene terephthalate, a base layer of polyester-based polyurethane and a top layer of polyurethane.

[0092] Post-consumer synthetic leather 2 comprises three layers, a fabric layer of polyethylene terephthalate, a base layer of polyether-based polyurethane and a top layer of polyurethane.

[0093] Post-consumer synthetic leather 3 comprises five layers, a polyethylene terephthalate nonwoven fabric layer, a diphenylmethane diisocyanate (MDI)-based polyurethane soft foam layer, a polyethylene terephthalate fabric layer, a polyether-based polyurethane base layer and a polyurethane top layer.

[0094] Polyether polyol PEOL-1, from BASF, is based on ethylene oxide and propylene oxide, has a functionality of 3 and a number average molecular weight of 5,000 g / mol, and a viscosity of 850 mPa s at 25°C.

[0095] Polyester polyol PESOL-1, based on adipic acid, butanediol and ethylene glycol, has a hydroxyl value of 56 mgKOH / g and a number average molecular weight of 2,000 g / mol, is a waxy solid at 25°C, and is from BASF.

[0096] Polyester polyol PESOL-2, based on adipic acid and diethylene glycol, having a hydroxyl value of 112 mgKOH / g and a number average molecular weight of 1,000 g / mol, and a viscosity of 1,864 mPa s at 25°C, was obtained from BASF.

[0097] Polyester polyol PESOL-3, based on adipic acid, glycerol and diethylene glycol, with a hydroxyl value of 56 mgKOH / g, a number average molecular weight of 2,500 g / mol, a functionality of 2.5, and a viscosity of 20,000 mPa s at 25° C., was obtained from BASF.

[0098] Measurement and test methods

[0099] The measurement and test methods are shown in Table 1.

[0100] The instantaneous peel strength is measured when the synthetic leather is peeled off from the release paper just after curing. The second peel strength of the synthetic leather refers to the peel strength measured 24 hours after the synthetic leather is cured. The test, including sample preparation and testing, is completed within 20 minutes.

[0101] Using POROS TM The amine content was determined by GCMS on a ThermoFisher TRACE 1300GC system with an R1 10 μm column. The carrier gas was helium. The injection temperature was 200° C. and the injection volume was 1 μL. The flow rate was 1 mL / min and the split ratio was 1:5. The flame ionization detector temperature was 290° C.

[0102] The content of nitrogen from isocyanate and terephthalic acid structural units in the mixture based on the recycled components was determined using quantitative nuclear magnetic resonance. The nitrogen from isocyanate was converted from the methylene content in the diphenylmethane diisocyanate (MDI) based polyurethane and / or polyurea structure, which was determined based on the 13C signal with a chemical shift of 40.0-42.0 ppm. The content of terephthalate structural units was determined based on the 13C signal with a chemical shift of 165.0-167.0 ppm.

[0103] Nitrogen content from isocyanate and terephthalic acid structural unit content in recovered polyols: About 200 mg of recovered polyol liquid sample was added to a 10 mL sample bottle, along with about 5 mg of chromium triacetylacetonate and about 5 mg of 1,3,5-trimethoxybenzene, the latter as an internal standard. The mass of the sample and internal standard should be recorded to an accuracy of 0.01 mg. About 600 μL of deuterated acetone was added to dissolve the sample and internal standard. The resulting mixture was transferred to a 5 mm NMR tube. If insoluble particles were present in the mixture, the sample bottle was rinsed with an additional 100 μL of deuterated acetone and the residue in the sample bottle was transferred to ensure complete sampling. The contents of the NMR tube should be mixed thoroughly by shaking or vortexing. Quantitative carbon NMR spectroscopy experiments were performed on a BRUKER 600 MHz spectrometer using the following parameters: pulse sequence zg30, 2048 scans, wait time D1 of 6 seconds, and sampling data points set to 65536. Phase correction and baseline correction were performed to achieve accurate integration. The methyl carbon spectrum shift of the solvent acetone was calibrated to 29.84 ppm.

[0104] After identifying the peaks corresponding to the methylene group and the internal standard in the MDI-based polyurethane and / or polyurea structure, the methylene content in the recovered polyol sample is calculated using the sample mass, the internal standard mass, and the peak area ratio of the methylene group in the MDI-based polyurethane and / or polyurea structure relative to the internal standard. Two parallel experiments were performed and the difference between the results should be less than 7%. The nitrogen content from the isocyanate was calculated based on the corresponding relationship between the methylene content and 1 methylene corresponding to 2 nitrogen atoms.

[0105] After identifying the peaks corresponding to the carbonyl carbon atom in the terephthalate structure and the internal standard, the sample mass, the internal standard mass, and the peak area ratio of the carbonyl carbon atom in the terephthalate structure relative to the internal standard are used to convert the terephthalic acid structural unit content in the recovered polyol sample, calculated as free terephthalic acid, i.e., C6H4(COOH)2. Two parallel experiments are performed and the difference between the results should be less than 7%. Two carbonyl carbon atoms correspond to one terephthalic acid molecule.

[0106] For further confirmation, the methylene carbon atom signals and carbonyl carbon atom signals in the MDI-based polyurethane and / or polyurea structure mentioned herein should form correlation peaks with hydrogen atoms with a chemical shift of 7.0-8.5 ppm in the 1H spectrum in the 1H-13C heteronuclear multi-carbon correlation spectrum (1H-13C HMBC).

[0107] Table 1 Measurement and test standards

[0108]

[0109] Degradation of synthetic leather

[0110] Post-consumer synthetic leather from discarded sofas was shredded into fragments. Post-consumer synthetic leather 1 was based on polyester polyols, and post-consumer synthetic leathers 2 and 3 were based on polyether polyols. Most of the fragments had a complete layered structure, and the fragment size was about 3 cm×3 cm×1.1 mm. These fragments were mixed with the liquid formulations listed in Table 2 to form a reaction system. The reaction system was then placed in a flask and heated at 230°C under a nitrogen atmosphere for 8 hours. After the heating was completed, a viscous mixture with a brown or dark color was obtained.

[0111] Nine recycling examples were carried out, marked as RE 1 to RE 9. The weights of synthetic leather fragments and liquid formulations and the degradation temperatures are given in Table 2. Sodium hydroxide catalyst was added to the reaction system of RE 9 in the form of an aqueous solution. Nine recycled mixtures (PD 1 to PD 9) were obtained. PD 1 to PD 5 and PD 7 to PD 9 appeared as suspensions with generally small solid particles; while flakes with a size greater than 1 cm x 1 cm were present in the liquid phase of PD 6. Their properties were tested. The viscosity of PD 6 could not be measured. Since PD 9 contained a large amount of free amines sufficient to interfere with the determination of the hydroxyl value, the titration experiment of the hydroxyl value was abandoned.

[0112] Table 2

[0113]

[0114] As can be seen from Table 2, when the degradation agent does not contain polyester polyol but only contains polyether polyol, the system obtained after heating has solid-liquid phase separation; while heating the degradation agent containing polyester polyol and synthetic leather fragments can obtain a uniform mixture. Comparing RE 4 and RE 9, if the reaction system contains alkali metal hydroxide, even if the addition amount is low (the addition amount in RE 9 is 0.24 weight % of the total reactants), a large amount of diamine is generated due to the catalytic effect of the base. Comparing RE 2 and RE 5, it is found that replacing a part of the polyester polyol PESOL-2 with a low-viscosity and non-reactive polyether polyol PEOL-1 can effectively reduce the viscosity of the final product.

[0115] Liquid chromatography-mass spectrometry and nuclear magnetic resonance analysis were performed on PD 1 to PD 5, PD 7 and PD 8, and the results showed that the PD 1 sample contained a structure represented by Formula 13, and the PD 2 to PD 5, PD 7 and PD 8 samples all contained a structure represented by Formula 14. This indicates that the degradation agent and the poly (ethylene terephthalate) in the synthetic leather underwent an ester exchange reaction.

[0116]

Claims

1. A recycled content based mixture comprising: A hydroxyl-terminated copolyester comprising a C4-C12 dicarboxylic acid structure represented by Formula 1 and a diol structure represented by Formula 2, wherein Q is a C2-C10 alkylene group and R is a C2 to C20 alkylene group; and —O—R—O— Formula 2; and at least one of the following: Dispersed polyurethanes or polyureas; and Hydroxyl terminated carbamate or urea, in, The recycled content-based mixture contains 1.0 wt. % to 20.0 wt. % of terephthalic acid structural units, expressed as C6H4(COOH)2, calculated based on quantitative nuclear magnetic resonance measurements.

2. The recycled content based mixture of claim 1 further comprising hydroxyl terminated oligomeric polyethylene terephthalate.

3. The recycled content based mixture of claim 1, wherein: The recycled content-based mixture contains less than 0.3 wt. % diamine, preferably less than 0.06 wt. % diamine, based on the total weight of the recycled content-based mixture, as determined by gas chromatography-mass spectrometry.

4. The recycled content based mixture according to claim 3, wherein: The diamine is selected from toluenediamine, methylenedianiline, naphthalenediamine, isophoronediamine, hexamethylenediamine, pentamethylenediamine, methylenebis(cyclohexylamine) and any combination thereof.

5. The recycled content based mixture of claim 1, wherein: The mixture based on recycled content has a total hydroxyl value of 20 to 250 mgKOH / g, preferably 40 to 120 mgKOH / g, more preferably 40 to 100 mgKOH / g.

6. The recycled content-based mixture of claim 1, further comprising a polyether polyol having a number average molecular weight of 1,000 to 10,000 g / mol.

7. The recycled content based mixture of claim 1, wherein: The recycled content based mixture contains 0.01 wt % to 1.50 wt % of isocyanate derived nitrogen present in urethane bonds and / or urea bonds, calculated based on quantitative nuclear magnetic resonance measurements.

8. A method comprising: (a) dividing the synthetic leather into a plurality of pieces; (b) mixing at least a portion of the fragments with a degradation agent to form a reaction mixture; (c) heating the reaction mixture at a temperature of 180°C to 260°C; and (d) obtaining a mixture based on the recovered components from the heated reaction mixture, The synthetic leather comprises a fabric layer of polyethylene terephthalate, a base layer and a top layer, at least one of the base layer and the top layer is made of polyurethane, The degradation agent includes a polyester polyol, and In step (c), the reaction mixture is heated in the absence of a catalyst.

9. The method of claim 8, wherein: In the plurality of fragments obtained in step (a), the fabric layer and the base layer are substantially not delaminated.

10. The method of claim 8, further comprising: (e) producing a polyurethane by reacting the recycled content based mixture with a polyisocyanate.

11. The method of claim 8, wherein: For each kg of fragments in step (b), 0.5 to 100 kg, preferably 1.2 to 10 kg, more preferably 1.5 to 3 kg of the degradation agent are added.

12. The method of claim 8, wherein: The weight content of the polyester polyol in the degradation agent is 10% to 100%, preferably 20% to 100%, more preferably 30% to 100%, and further preferably 40% to 100%.

13. The method of claim 8, wherein: The polyester polyol has a number average molecular weight of 300 to 6,000 g / mol, preferably 500 to 3,000 g / mol, more preferably 1,000 to 2,500 g / mol.

14. The method of claim 8, wherein: The polyester polyol has an average functionality of 1.8 to 3.

2.

15. The method of claim 8, wherein: The degradation agent includes a polyether polyol having a number average molecular weight of 1,000 to 10,000 g / mol.

16. The method of claim 8, wherein: In step (c), the reaction mixture is heated for at least one hour, preferably in step (c), the reaction mixture is heated for 1 to 48 hours, more preferably in step (c), the reaction mixture is heated for 2 to 24 hours.

17. The method of claim 8, wherein: In step (c), the reaction mixture is heated under a protective atmosphere.

18. A polyurethane prepared from a reaction system comprising an isocyanate and the recycled content-based mixture according to any one of claims 1 to 7.

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