Degradation and regeneration method of waste polyurethane urea

Abstract

The invention provides a waste polyurethane urea degradation and regeneration method, which belongs to the technical field of renewable resources, and comprises the following steps: mixing waste polyurethane urea, a compound alcoholysis agent and a compound catalyst, heating, stirring, and cooling to obtain a degraded recovery product. According to the method for degrading and regenerating the waste polyurethane urea, the waste polyurethane urea is recycled after being degraded, so that the purposes of improving the economic benefit and achieving environmental friendliness are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of renewable resources, and in particular to a method for degrading and regenerating waste polyurethane urea. Background Art

[0002] Polyurethane is a polymer material formed by the reaction of terminal isocyanate compounds and polyol compounds. The reaction requires a catalyst and a certain temperature. Its polymer chain contains a variety of chemical bonds, mainly carbamate bonds. Polyurea is formed by the reaction of terminal polyisocyanate and terminal polyamine. It does not require a catalyst and reacts quickly. Its polymer chain also contains a variety of chemical bonds, mainly urea bonds. Polyurethane urea is a special type of polyurethane. The polyurethane urea molecular chain is mainly composed of carbamate bonds and urea bonds, and has good elasticity and wear resistance.

[0003] Polyurethane is generally obtained by the reaction of oligomeric diols (or triols), diisocyanates and small molecule polyols (chain extenders and crosslinkers). The raw materials do not contain amine substances. This polyurethane can be prepared by a one-step method and a prepolymer method (two-step method). Polyurea is generally obtained by the direct reaction of amino-terminated polyethers (polyether diamines and polyether triamines), diisocyanates (commonly used liquefied MDI) and aromatic diamines (commonly used liquid diamines such as DETDA) to obtain spray polyurea elastomers (SPUA). Since amino groups react quickly with isocyanate groups, spray molding technology is required for preparation. If one component is a mixture of amino-terminated polyethers and aromatic diamines, and the other component is an isocyanate-terminated polyurethane prepolymer, what is obtained by spray molding is not a pure polyurea elastomer, but a polyurethane urea, because there are a small amount of carbamate groups in its molecular chain. Polyurethane urea is first obtained by the reaction of oligomeric diols (or triols) with diisocyanates to obtain a prepolymer, and then the prepolymer is cured by reaction with a polyamine chain extender.

[0004] It can be seen that there are similarities and differences between polyurethane, polyurea and polyurethane urea. Their similarities are as follows: in the formation of polyurethane, polyurea and polyurethane urea, they must react with compounds containing isocyanate; the types of chemical bonds of the hardened polymer chains are similar; waste polyurethane, waste polyurea and waste polyurethane urea have hazards such as insolubility and infusibility, and pollute the environment. Their differences are that although the polymer chain structure of the hardened materials is similar, the key functional group in the polyurethane material is the carbamate bond, the key functional group in the polyurea material is the urea bond, and the key functional groups in the polyurethane urea material are the carbamate bond and the urea bond.

[0005] The bond energy of urea bond is usually 148kJ / mol, and the bond energy of ester bond is usually 20-50kJl / mol. It can be seen that the strength of urea bond is higher than that of ester bond. Polyurethane is prone to thermal degradation at high temperature and is easily damaged in strong acid and strong base environment; polyurea has more urea bonds in its molecular chain, so its thermal stability and chemical stability are usually better; and polyurethane urea has better thermal stability and chemical stability than polyurethane due to the presence of urea bonds. Therefore, the degradation method of polyurethane cannot be directly applied to the degradation of polyurethane urea.

[0006] The difference in molecular structure between polyurethane and polyurethaneurea leads to differences in the degradation process and performance of polyurethane and polyurethaneurea. The degradation process of polyurethane is usually explained as the urea ester group (such as -NHCOO-) in polyurethane will break under the action of alcohol and catalyst, and be replaced by a short alcohol chain, thereby releasing long-chain polyols and aromatic compounds. In this process, the molecular chain of polyurethane is interrupted to generate products with lower molecular weight. Transesterification reaction of polyurethane:

[0007] The degradation of polyurethane urea is different from that of urea urea. In addition to the carbamate bond, the urea bond and other possible chemical bonds in the polyurethane urea molecular chain are broken under the action of alcohol and catalyst. These broken fragments then react with alcohol compounds to generate polyols, amine compounds and other possible degradation products. The specific reaction process may involve various reaction types such as ester exchange and amide exchange. Ester exchange reaction of polyurethane urea:

[0008] Due to its performance advantages, polyurethane urea is widely used in fields such as architectural coatings. With the large-scale use of polyurethane urea, the treatment of waste polyurethane urea materials has become an urgent problem to be solved. Summary of the invention

[0009] In view of this, the present invention provides a method for degrading and regenerating waste polyurethane urea, which regenerates the waste polyurethane urea after degradation treatment, thereby improving economic benefits and achieving the purpose of being environmentally friendly.

[0010] To achieve the above object, the present invention provides a method for degrading waste polyurethane urea, comprising the following steps: mixing waste polyurethane urea, a compound alcoholysis agent and a compound catalyst, heating and stirring, and obtaining a degradation recovery product after cooling.

[0011] Optionally, the mass ratio of the compound alcoholysis agent to the waste polyurethane urea is 1:0.5-1.5; the amount of the compound catalyst added is 0.1-1% of the total mass of the reactants; and the heating and stirring conditions are a temperature of 160-220°C and a stirring time of 1-10 hours.

[0012] Optionally, the composite catalyst is a mixture of a nano titanium glycol catalyst and an inorganic catalyst; the inorganic catalyst is an alkali metal hydroxide or an alkaline earth metal hydroxide.

[0013] Optionally, the preparation method of the nano titanium glycolate comprises the following steps: dissolving a titanium-containing compound in ethylene glycol to form a solution, placing the solution in a polytetrafluoroethylene-lined reactor for a hydrothermal synthesis reaction; cooling naturally after the reaction, filtering, washing and drying to obtain the nano titanium glycolate.

[0014] Optionally, the mass ratio of the titanium-containing compound to ethylene glycol is 1:60-200; the temperature of the hydrothermal synthesis reaction is 120-200°C, and the reaction time is 2-24h; a porous PTFE filter membrane with a pore size of 0.10-0.35μm is used during the filtration; the washing is to wash the filtered solid 3-5 times with distilled water and ethanol in sequence; the drying is to dry the washed solid at a temperature of 50-100°C for at least 8 hours to obtain ethylene glycol titanium nanomaterial. Optionally, the titanium-containing compound is one or a combination of two or more of titanium isopropoxide, tetrabutyl titanate, titanyl sulfate, tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetraisopropyl titanate, tetrakis(trimethylsilyl)titanium, and diisopropyl bis(acetylacetonate) titanate.

[0015] Optionally, the alkali metal hydroxide catalyst is one or a combination of two or more of lithium hydroxide, sodium hydroxide, calcium hydroxide and potassium hydroxide.

[0016] Optionally, the composite alcoholysis agent is one or a combination of two or more of 1,4-butanediol, 1,3-butanediol, 1,3-propylene glycol, ethylene glycol, diethylene glycol, 1,2-propylene glycol, diethylene glycol, pentanediol, butynediol, 1,6-hexanediol, 1,2-hexanediol, 1,2-cyclohexanediol, and 1,3-cyclohexanediol.

[0017] In order to achieve the above object, the present invention provides a method for regenerating waste polyurethane urea, such as preparing a regenerated polyurethane foam insulation material or a regenerated polyurea material from the above-mentioned degradation recovery product.

[0018] Optionally, the preparation of the recycled polyurethane foam insulation material includes the following steps: the recycled degradation product is evenly mixed with a chain extender, a foaming agent, a foam stabilizer, a foaming catalyst and water to obtain a white material, which is then mixed with a black material to foam it, and cooled to obtain the recycled polyurethane foam insulation material.

[0019] Optionally, the added amounts of the chain extender, foaming agent, foam stabilizer, foaming catalyst, water and black material are 1-30%, 1-20%, 0.1-2%, 0.1-10%, 1-10% and 1-60% of the total mass of the reactants, respectively; the added amount of the degradation recovery product is 5-10% of the total mass of the reactants, and the total mass proportion of the chain extender, foaming agent, foam stabilizer, foaming catalyst, water and black material is 100%.

[0020] Optionally, the chain extender is one or a combination of two or more of diethyltoluenediamine, dimethylthiotoluenediamine, 3,3′-dichloro-4,4′-diaminodiphenylmethane, N,N′-dialkylmethyldiphenylamine, polyether polyol, ethylene glycol, 1,4-butanediol, propylene glycol, glycerol, sorbitol, sucrose, and glucose.

[0021] The diethyltoluenediamine, dimethylthiotoluenediamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-dialkylmethyldiphenylamine used in the present invention contain two amino groups and can react with isocyanate to generate urea groups, thereby giving the polyurethane urea good physical and mechanical properties. At the same time, some amine chain extenders may generate alkaline substances during the degradation process, which helps to alleviate the self-catalytic phenomenon of acidic products generated by the degradation of polyester segments, thereby controlling the degradation rate; the polyether polyol used in the present invention reacts with isocyanate to generate carbamate and urea groups, thereby improving the structure and performance strength of the polyurethane urea; although the ethylene glycol, 1,4-butanediol and propylene glycol used in the present invention do not directly play a degradation role in the degradation process of the polyurethane urea, as part of the polyurethane urea molecular chain, their structure and properties will affect the overall degradability of the material, thereby facilitating the recycling of waste materials.

[0022] Optionally, the foaming agent is one or a combination of two or more of triethylenediamine, azodicarbonamide, N,N-azobisisobutyronitrile, dicyandiamide, antimony trioxide, 1,1-dichloro-1-fluoroethane, dichlorofluoroethane, monofluorodichloroethane, monofluorotrichloromethane, N,N-dinitrosopentamethylenetetramine, and N,N-dimethyl-N,N,-dinitrosotobenzene.

[0023] Optionally, the foam stabilizer is one or a combination of two or more of magnesium oxide, calcium aluminate, polyether, and silicone oil.

[0024] Optionally, the silicone oil is one or a combination of two or more of silicone oil L-600, silicone oil SE-232, silicone oil CGY-5, hexadecyl / octadecyl dimethyl tertiary amine, C12 tertiary amine, dodecyl / tetradecyl dimethyl tertiary amine, and dimethyl siloxane.

[0025] Optionally, the foaming catalyst is one or a combination of two or more of pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, dimethylethanolamine, 1,8-naphthalic anhydride, phthalic anhydride, cyclopentanoic anhydride, hexanodioic anhydride, cyclobutanetetracarboxylic anhydride, succinic anhydride, ethanolamine, diethanolamine, triethanolamine, 3-propanolamine, monoisopropylamine, diisopropylamine, triisopropylamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, and organotin.

[0026] Optionally, the black material is one or a combination of two or more of methyl methacrylate, diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, p-carboxybenzoic acid, neopentyl glycol diacrylate, neopentyl glycol diacrylate and neopentyl glycol diglycidyl ether.

[0027] Optionally, the preparation of the recycled polyurea material includes the following steps: the recycled degradation product is uniformly mixed with the amino-terminated polyether, liquid amine chain extender and additives to form a white material, which is then mixed with a semi-prepolymer to perform addition polymerization, and then sprayed to form a recycled polyurea material.

[0028] Optionally, the added amounts of the amino-terminated polyether, liquid amine chain extender, additives and semi-prepolymer are 8% to 20%, 10% to 20%, 1% to 10% and 50% to 60% of the total mass of the reactants, respectively; the added amount of the degradation recovery product is 10 to 25% of the total mass of the reactants, and the total mass proportion of the amino-terminated polyether, liquid amine chain extender, additives and semi-prepolymer is 100%.

[0029] Optionally, the amino-terminated polyether is a polyether polyol with a hydroxyl value controlled within the range of 25 to 1050 and a functionality selected within the range of 2 to 6.

[0030] Optionally, the liquid amine chain extender is one or a combination of two or more of diethyltoluenediamine, 3,3′-dichloro-4,4′-diaminodiphenylmethane, dimethylthiotoluenediamine, and N,N′-dialkylmethyldiphenylamine.

[0031] Optionally, the auxiliary agents include antioxidants, ultraviolet light stabilizers, colorants, dispersants, anti-settling agents and water absorbents.

[0032] Optionally, the semi-prepolymer is obtained by prepolymerizing carbodiimidized diisocyanate or polymethylene polyphenyl polyisocyanate, and the isocyanate content of the semi-prepolymer is 12% to 27%.

[0033] The above technical solution of the present invention includes at least the following beneficial effects: (1) The present invention compounds waste polyurethane urea with a compound alcoholysis agent, a nano-titanium glycolate catalyst and an inorganic catalyst, which, on the one hand, promotes the degradation of waste polyurethane urea, and on the other hand, helps to prepare recycled materials from waste polyurethane urea. The nano-titanium glycolate catalyst has a large specific surface area and high surface energy, thereby providing more catalytic active sites. In the preparation process of recycled polyurethane materials or recycled polyurea materials, it can fully react with various raw materials, improve production efficiency, and facilitate large-scale production; (2) Nano-titanium glycolate catalyst can accurately promote the reaction between isocyanate and hydroxyl groups. It may be more inclined to reduce the activation energy of the main reaction and relatively less to reduce the activation energy of the side reaction. It can stabilize certain reaction intermediates, thereby reducing the occurrence of side reactions and ensuring that the reaction proceeds in the desired direction, so as to improve the purity and quality of the recycled materials and make the relevant properties of the recycled materials meet the requirements; (3) In addition, the nano-titanium ethylene glycol catalyst and the inorganic catalyst have good stability when combined. The nano-titanium ethylene glycol catalyst and the inorganic catalyst may have different active sites. When the two are combined, these active sites can complement each other to form a more comprehensive and efficient catalytic system. At the same time, inorganic catalysts generally have a higher melting point or higher thermal stability, which can protect the nano-titanium ethylene glycol catalyst from being damaged by high temperatures. In addition, inorganic catalysts may have higher chemical inertness, which can prevent the nano-titanium ethylene glycol catalyst from being damaged by active substances in the reaction medium. Therefore, it helps to extend the service life of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the SEM image of nano titanium glycolate in the embodiment; Figure 2 This is an electron microscope scanning image of the recycled polyurethane (PU) material in Example 1 of the present invention; Figure 3 This is an electron microscope scanning image of PU of comparative example 1 of the present invention; Figure 4 This is the infrared scanning FT-IR diagram of Comparative Example 1 of the present invention; Figure 5 This is a physical picture of the hard polyurethane urea material prepared in Examples 4, 5, and 6; Figure 6 This is a physical picture of the hard polyurethane urea material prepared in Comparative Example 2. DETAILED DESCRIPTION

[0035] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the following will be combined with the appended drawings of the embodiments of the present invention. Figures 1 to 6, the technical scheme of the embodiment of the present invention is clearly and completely described. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0036] Example 1 1. Preparation of Nano-Titanium Glycol Take 500 μL of tetrabutyl titanate and dissolve it in 60 mL of ethylene glycol, and stir at room temperature (25 ° C) until a clear solution is formed. The density of tetrabutyl titanate is 1 g / ml and the density of ethylene glycol is 1.11 g / cm³. Transfer this solution to a 100 mL polytetrafluoroethylene-lined autoclave and stir vigorously at 160 ° C for 8 hours. After cooling naturally to room temperature, collect the precipitated solid through a PTFE filter with a pore size of 0.1 μm. Repeatedly wash with distilled water and ethanol for 3 times each. Dry the washed solid in a vacuum oven at 70 ° C for 8 hours to obtain ethylene glycol titanium white solid powder.

[0037] 2. Preparation of rigid polyurethane foam (1) 100 g of waste polyurethane urea was mixed with 50 g of diethylene glycol, 50 g of 1,3-propylene glycol, 0.6 g of potassium hydroxide, and 0.4 g of nano-titanium glycolate, stirred at 160° C. for 2 hours, and cooled to room temperature to obtain a degraded recovery product.

[0038] (2) 10 g of the recycled product after degradation was mixed with 20 g of polyether polyol 4110, 13 g of monofluorodichloroethane, 2.5 g of silicone oil CGY-5, 1.0 g of succinic anhydride, 0.1 g of triethanolamine, 0.1 g of organotin and 7.6 g of water to obtain a white material, which was then stirred with 45.70 g of methyl methacrylate for 25 seconds to foam the material. The recycled polyurethane foam insulation material was obtained by cooling, which was a rigid polyurethane foam material.

[0039] Example 2 1. Preparation of Nano-Titanium Glycol Take 500 μL of tetrabutyl titanate and dissolve it in 60 mL of ethylene glycol, and stir at room temperature (25 ° C) until a clear solution is formed. The density of tetrabutyl titanate is 1 g / ml and the density of ethylene glycol is 1.11 g / cm³. Transfer this solution to a 100 mL polytetrafluoroethylene-lined autoclave and stir vigorously at 180 ° C for 12 hours. After cooling naturally to room temperature, collect the precipitated solid through a PTFE filter with a pore size of 0.22 μm. Repeatedly wash with distilled water and ethanol for 5 times each. The solid obtained after washing is dried in a vacuum oven at 50 ° C for 12 hours to obtain ethylene glycol titanium white solid powder.

[0040] 2. Preparation of rigid polyurethane foam (1) 100 g of waste polyurethane urea was mixed with 45 g of 1,4-butanediol, 55 g of 1,2-propylene glycol, 0.6 g of sodium hydroxide, 0.4 g of nano-titanium glycol, and 0.6 g of potassium hydroxide, stirred at 180° C. for 3 hours, and cooled to room temperature to obtain a degraded recovery product.

[0041] (2) 10 g of the recovered product after degradation was mixed with 20 g of polyether polyol 4110, 13 g of triethylene diamine, 2.5 g of silicone oil L-600, 0.1 g of ethanolamine, 0.1 g of adipic anhydride and 8.6 g of water to form a white material, which was then stirred with 45.70 g of toluene diisocyanate for 25 seconds to foam the material. The recycled polyurethane foam insulation material was obtained by cooling, which was a rigid polyurethane foam material.

[0042] Example 3 1. Preparation of Nano Titanium Glycol Take 1 mL of titanyl sulfate and dissolve it in 100 mL of ethylene glycol, and stir it at room temperature until it is clear. The density of titanyl sulfate is 1.40 g / cm³, and the density of ethylene glycol is 1.11 g / cm³. Transfer the solution to an autoclave and react at 140°C for 6 hours. After cooling naturally to room temperature, collect the precipitated solid through a PTFE filter with a pore size of 0.25 μm. Repeatedly wash with distilled water and ethanol for 3 times each. Dry the washed solid in a vacuum oven at 70°C for 12 hours to obtain a white solid powder of ethylene glycol titanium.

[0043] 2. Preparation of rigid polyurethane foam (1) 100 g of waste polyurethane urea was mixed with 40 g of diethylene glycol, 30 g of pentanediol, 30 g of 1,3-butanediol, 0.6 g of calcium hydroxide, and 0.4 g of nano-titanium glycol, stirred at 220° C. for 1 hour, and cooled to room temperature to obtain a degraded recovery product.

[0044] (2) 10 g of the recovered product after degradation was mixed with 20 g of polyether polyol 4110, 13 g of N,N-azobisisobutyronitrile, 2.5 g of octadecyldimethyl tertiary amine, 1.0 g of monoethanolamine, 0.1 g of 3-propanolamine, 0.1 g of diisopropanolamine, and 7.6 g of water to form a white material, and then stirred with 45.70 g of hexamethylene diisocyanate for 25 seconds to foam it, and cooled to obtain a recycled polyurethane foam insulation material, which is a rigid polyurethane foam material.

[0045] Example 4 1. Preparation of Nano Titanium Glycol Take 1 mL of titanyl sulfate and dissolve it in 100 mL of ethylene glycol, and stir it at room temperature until it is clear. The density of titanyl sulfate is 1.40 g / cm³, and the density of ethylene glycol is 1.11 g / cm³. Transfer the solution to an autoclave and react at 190°C for 24 hours. After cooling naturally to room temperature, collect the precipitated solid through a PTFE filter with a pore size of 0.30 μm. Repeatedly wash with distilled water and ethanol for 3 times each. Dry the washed solid in a vacuum oven at 70°C for 12 hours to obtain a white solid powder of ethylene glycol titanium.

[0046] 2. Preparation of rigid polyurea materials (1) 100 g of waste polyurethane urea was mixed with 30 g of 1,6-hexanediol, 40 g of ethylene glycol, 30 g of ‌1,2-hexanediol, 0.6 g of lithium hydroxide, and 0.4 g of nano-titanium glycol, stirred at 190° C. for 5.0 hours, and cooled to room temperature to obtain a degraded recovery product.

[0047] (2) 3.0 g of the recovered degradation product and 2.4 g of polyether polyol, the hydroxyl value of the polyether polyol being controlled within the range of 25 to 1050 and the functionality being selected within the range of 2 to 6; 2.0 g of diethyltoluenediamine, 2 g of 3,3′-dichloro-4,4′-diaminodiphenylmethane and 1.0 g of an auxiliary agent are stirred evenly, and mixed with 11 g of carbodiimide diisocyanate to obtain a regenerated polyurea material, i.e., a hard polyurea material.

[0048] Example 5 1. Preparation of Nano-Titanium Glycol Take a mixture of 750 μL of tetrabutyl titanate and 250 μL of titanyl sulfate and dissolve it in 80 mL of ethylene glycol, and stir it at room temperature until it is clear. The density of tetrabutyl titanate is 1 g / ml, the density of titanyl sulfate is 1.40 g / cm³, and the density of ethylene glycol is 1.11 g / cm³. Transfer the solution to an autoclave and react at 150°C for 10 hours. After cooling naturally to room temperature, collect the precipitated solid through a PTFE filter with a pore size of 0.32 μm. Repeatedly wash with distilled water and ethanol for 3 times each. Dry the washed solid in a vacuum oven at 70°C for 12 hours to obtain a white solid powder of ethylene glycol titanium.

[0049] 2. Preparation of rigid polyurea materials (1) 100 g of waste polyurethane urea was mixed with 35 g of 1,3-cyclohexanediol, 30 g of pentanediol, 35 g of 1,2-propylene glycol, 0.6 g of lithium hydroxide, and 0.4 g of nano-titanium glycol, and stirred at 210° C. for 6.0 hours. After cooling to room temperature, a degraded recovery product was obtained.

[0050] (2) 3.9 g of the recycled product after degradation and 2.0 g of polyether polyol, the hydroxyl value of the polyether polyol being controlled within the range of 25 to 1050 and the functionality being selected within the range of 2 to 6; 2.2 g of dimethylthiotoluenediamine, 2 g of N,N'-dialkylmethyldiphenylamine and 1.0 g of an auxiliary agent were stirred evenly, and mixed with 11.5 g of polymethylene polyphenyl polyisocyanate to obtain a recycled polyurea material, i.e., a hard polyurea material.

[0051] Example 6 1. Preparation of Nano-Titanium Glycol Take a mixture of 750 μL of tetrabutyl titanate and 250 μL of tetrapropyl titanate and dissolve it in 120 mL of ethylene glycol, and stir it at room temperature until it is clear. The density of tetrabutyl titanate is 1 g / ml, the density of tetrapropyl titanate is 0.96 g / ml, and the density of ethylene glycol is 1.11 g / cm³. Transfer the solution to an autoclave and react at 120°C for 8 hours. After cooling naturally to room temperature, collect the precipitated solid through a PTFE filter with a pore size of 0.35 μm. Repeatedly wash with distilled water and ethanol for 4 times each. Dry the washed solid in a vacuum oven at 50°C for 20 hours to obtain a white solid powder of ethylene glycol titanium.

[0052] 2. Preparation of rigid polyurea materials (1) 100 g of waste polyurethane urea was mixed with 40 g of butynediol, 30 g of 1,3-propylene glycol, 30 g of 1,2-cyclohexanediol, 0.6 g of potassium hydroxide, and 0.4 g of nano-titanium glycol, and stirred at 200° C. for 9 hours. After cooling to room temperature, a degraded recovery product was obtained.

[0053] (2) 4.0 g of the recycled product after degradation and 3.0 g of polyether polyol, the hydroxyl value of the polyether polyol being controlled within the range of 25 to 1050 and the functionality being selected within the range of 2 to 6; 1.5 g of dimethylthiotoluenediamine, 2 g of diethyltoluenediamine and 1.0 g of an auxiliary agent are stirred evenly, and mixed with 12 g of carbodiimidized diisocyanate to obtain a regenerated polyurea material, i.e., a hard polyurea material.

[0054] Comparative Example 1 Compared with Example 1, the only difference is that polyether polyol 4110 is used to replace the recycled product after degradation, and the remaining steps are consistent with the raw materials to obtain a rigid polyurethane foam material.

[0055] Comparative Example 2 Compared with Example 6, the only difference is that polyether polyol is used to replace the recovered product after degradation, and the remaining steps are consistent with the raw materials to obtain a hard polyurea material.

[0056] The properties of the rigid polyurethane foam materials prepared in Examples 1 to 3 and Comparative Example 1 were tested, and the results are shown in Table 1.

[0057] Table 1 Performance of rigid polyurethane foam materials prepared in Examples 1 to 3 and Comparative Example 1

[0058] Electron microscope scanning was performed on Example 1 and Comparative Example 1 to obtain Figure 2 and Figure 3 , infrared scanning was performed on Example 1 to obtain Figure 4 .

[0059] Figure 2 This is an electron microscope scanning image of the recycled polyurethane (PU) material of Example 1. The pores of the recycled PU are smaller, and the pore structure is relatively more uniform and complete, with a thicker skeleton and thicker pore walls. Figure 3 This is an electron microscope scanning image of the PU of comparative example 1. The pore size of the PU is uneven and the arrangement is irregular. Figure 4 This is the FT-IR image of Comparative Example 1, 3409-3418 cm -1 The stretching vibration of NH bond is 2950-2850cm -1 The stretching vibration of methyl and methylene is at 2280-2260cm -1 The left and right sides are the asymmetric stretching vibration of -NCO, 1745-1730cm -1 The stretching vibration of the ester carbonyl C=O is 1708-1703cm -1 The stretching vibration of the amide carbonyl C=O, 1690-1640cm -1 The stretching vibration of C=O in urea is 1600-1580cm -1 Benzene ring skeleton vibration, 1500-1450cm -1 Benzene ring skeleton vibration and CH angle vibration, 1540-1530cm -1 and 1315-1305cm -1 They are amide II and amide III bands, 1230-1220 cm -1 and 1115-1080cm -1 650-590cm-1 is the stretching vibration of -NCO in ester and ether groups respectively. Figure 4 It can be seen that the material prepared in Comparative Example 1 is a polyurethane foam material. Figure 2 and Figure 3 It can be seen that the recycled polyurethane material prepared by the present invention is superior to the polyurethane material in terms of structural performance.

[0060] As shown in Table 1, the recycled polyurethane materials prepared in Examples 1 to 3 have greater strength, lower density, and similar thermal conductivity than the polyurethane material prepared in Comparative Example 1.

[0061] Figure 5This is a diagram of the hard polyurethane urea material prepared in Examples 4, 5, and 6, whose appearance and performance are similar to those of Comparative Example 2. Figure 6 This is a picture of the hard polyurethane urea material prepared in Comparative Example 2.

[0062] The performance of the hard polyurea materials prepared in Examples 4 to 6 and Comparative Example 2 was tested and the results are shown in Table 2.

[0063] Table 2 Performance of hard polyurea materials prepared in Examples 4 to 6 and Comparative Example 2

[0064] As shown in Table 2, the regenerated polyurea materials prepared in Examples 4 and 6 of the present invention have shorter gel time and higher hardness than the hard polyurea material prepared in Comparative Example 2, and the regenerated polyurea material prepared in Example 5 has better comprehensive performance than the hard polyurea material prepared in Comparative Example 2. It can be seen that the regenerated polyurea material prepared in the present invention has better performance than the existing polyurea material, and the use of waste polyurethane urea as raw material in the present invention can greatly save raw materials, protect the environment, and have good economic and social benefits.

[0065] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for degrading waste polyurethane urea, characterized in that: The method comprises the following steps: mixing waste polyurethane urea, a compound alcoholysis agent and a compound catalyst, heating and stirring, and obtaining a degradation recovery product after cooling.

2. The method for degrading waste polyurethane urea according to claim 1, characterized in that: The mass ratio of the compound alcoholysis agent to the waste polyurethane urea is 1:0.5-1.5; the amount of the compound catalyst added is 0.1-1% of the total mass of the reactants; the heating and stirring conditions are a temperature of 160-220°C and a stirring time of 1-10 hours.

3. The method for degrading waste polyurethane urea according to claim 1, characterized in that: The composite catalyst is a mixture of a nano titanium glycol catalyst and an inorganic catalyst; the inorganic catalyst is an alkali metal hydroxide or an alkaline earth metal hydroxide.

4. The method for degrading waste polyurethane urea according to claim 3, characterized in that: The alkali metal hydroxide catalyst is one or a combination of two or more of lithium hydroxide, sodium hydroxide, calcium hydroxide and potassium hydroxide.

5. The method for degrading waste polyurethane urea according to claim 1, characterized in that: The composite alcoholysis agent is one or a combination of two or more of 1,4-butanediol, 1,3-butanediol, 1,3-propylene glycol, ethylene glycol, diethylene glycol, 1,2-propylene glycol, diethylene glycol, pentanediol, butynediol, 1,6-hexanediol, 1,2-hexanediol, 1,2-cyclohexanediol, and 1,3-cyclohexanediol.

6. A method for regenerating waste polyurethane urea, characterized in that: The recycled degradation product as claimed in any one of claims 1 to 5 is used to prepare a recycled polyurethane foam insulation material or a recycled polyurea material.

7. The method for regenerating waste polyurethane urea according to claim 6, characterized in that: The preparation of the recycled polyurethane foam insulation material comprises the following steps: the recycled degradation product is uniformly mixed with a chain extender, a foaming agent, a foam stabilizer, a foaming catalyst and water to obtain a white material, which is then mixed with a black material to foam the white material, and then cooled to obtain the recycled polyurethane foam insulation material.

8. The method for regenerating waste polyurethane urea according to claim 7, characterized in that: The added amounts of the chain extender, foaming agent, foam stabilizer, foaming catalyst, water and black material are 1-30%, 1-20%, 0.1-2%, 0.1-10%, 1-10% and 1-60% of the total mass of the reactants, respectively; the added amount of the degradation recovery product is 5-10% of the total mass of the reactants, and the total mass proportion of the chain extender, foaming agent, foam stabilizer, foaming catalyst, water and black material is 100%.

9. The method for regenerating waste polyurethane urea according to claim 6, characterized in that: The preparation of the recycled polyurea material comprises the following steps: the recycled degradation product is uniformly mixed with amino-terminated polyether, liquid amine chain extender and auxiliary agent to form a white material, which is then mixed with semi-prepolymer to make addition polymerization reaction, and then sprayed to form recycled polyurea material.

10. The method for regenerating waste polyurethane urea according to claim 9, characterized in that: The added amounts of the amino-terminated polyether, liquid amine chain extender, auxiliary agent and semi-prepolymer are 8%-20%, 10%-20%, 1%-10% and 50%-60% of the total mass of the reactants, respectively; the added amount of the degradation recovery product is 10-25% of the total mass of the reactants, and the total mass proportion of the amino-terminated polyether, liquid amine chain extender, auxiliary agent and semi-prepolymer is 100%.

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