Recycling method of waste polyamide elastomer foaming material

Abstract

The invention discloses an efficient recycling method for a waste polyamide elastomer foaming material, and aims to realize recycling of the waste polyamide elastomer foaming material while ensuring product performance through innovative cleaning, crushing and melt blending regeneration technologies, so that resource waste and environmental burden are effectively reduced.

Description

Technical field:

[0001] The invention relates to a recycling technology of polyamide elastomer foaming materials, and in particular to an environmentally friendly, economical and efficient recycling method suitable for processing waste of various polyamide elastomer foaming materials to achieve the recycling of resources. Technical background:

[0002] Polyamide elastomers are a type of elastomeric material that consists of highly rigid polyamide as the hard segment and flexible polyether as the soft segment. They have the advantages of low density, wide hardness range, high resilience, fatigue resistance, oil resistance, and chemical resistance. In recent years, polyamide elastomers have received a lot of attention in the field of foaming materials. Compared with thermoplastic elastomer foaming materials such as polyurethane elastomers, polyolefin elastomers or ethylene-vinyl acetate, foaming materials prepared from polyamide elastomers have better rebound performance and lower density, and thus have been widely used in the field of sports shoes, especially high-end running shoes.

[0003] During the processing and after-use of polyamide elastomer foam materials, a large amount of foam material waste will be generated, which not only causes a waste of resources but also causes environmental pollution. The effective recycling of these wastes has become an urgent problem to be solved. Traditional physical recycling methods often face the challenges of complex processes and reduced physical properties of recycled materials, which limits the recovery rate and reuse value of such high-value materials. Summary of the invention:

[0004] The purpose of the present invention is to provide an environmentally friendly, economical and efficient recycling method for waste polyamide elastomer foaming materials.

[0005] In order to achieve the above invention object, the technical solution of the present invention is as follows:

[0006] A method for recycling waste polyamide elastomer foaming materials comprises the following steps:

[0007] 1) Cleaning polyamide elastomer foam material waste;

[0008] 2) crushing the cleaned polyamide elastomer foaming material to prepare polyamide elastomer foaming waste particles;

[0009] 3) The polyamide elastomer foaming waste particles are mixed with at least one low melt index polyamide elastomer, at least one epoxy compound, and at least one polyisocyanate or isocyanate prepolymer, and then put into a twin-screw extruder for melt extrusion to prepare recycled polyamide elastomer particles that can be reused.

[0010] As a preferred solution, the total mass of the mixture is 100%, and the mass percentages are as follows:

[0011] Polyamide elastomer foam waste particles 5% to 90%; preferably 15% to 80%; more preferably 25% to 70%

[0012] Low melt index polyamide elastomer 5% to 90%; preferably 15% to 80%; more preferably 25% to 70%

[0013] Epoxy compound 0.01% to 5%; preferably 0.05% to 4%; more preferably 0.1% to 3%

[0014] Polyisocyanate or isocyanate prepolymer 0.01% to 5%; preferably 0.05% to 4%; more preferably 0.1% to 3%.

[0015] The present invention proposes a highly efficient recycling method for waste polyamide elastomer foaming materials, which aims to prepare reusable polyamide elastomer recycled particles by washing and crushing the waste polyamide elastomer foaming materials through innovative washing, crushing, and melt blending regeneration technology, and then mixing and melt-extrude with at least one polyamide elastomer with a low melt index, at least one polyisocyanate or isocyanate prepolymer, and at least one epoxy resin. The main technical advantage of the present invention is that polyisocyanate and epoxy resin are introduced simultaneously during the melt recovery process of polyamide elastomer foaming materials, which not only has a chain extension effect, but also reacts with epoxy groups to introduce polyoxazolidone groups into the polyamide elastomer, thereby improving the heat resistance of the polyamide elastomer.

[0016] In the present invention, the low melt index polyamide elastomer has a melt index of 1 to 100 g / 10 min, preferably 2 to 75 g / 10 min, and more preferably 3 to 50 g / 10 min, measured at a temperature of 235° C. and a load of 2.16 kg according to ISO 1133-1-A method.

[0017] In the present invention, the Shore hardness of the low melt index polyamide elastomer is selected from 50A to 80D, preferably 60A to 70D, and more preferably 70A to 60D.

[0018] In the present invention, the polyamide elastomer generally refers to a copolymer having a polyamide block (hard segment) and a polyether block (soft segment).

[0019] Examples of the polyamide block include polyamide structures derived from poly-ε-decamide (nylon 6), polybutylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene adipamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecanediamide (nylon 116), polyundecamide (nylon 11), polydodecanamide (nylon 12), polyhexamethylene isophthalamide (nylon 6I), polyhexamethylene terephthalamide (nylon 6T), polynonamethylene terephthalamide (nylon 9T), and polymethylene adipamide (nylon MXD6), etc. The polyamide block may be a combination of units constituting these polyamide structures.

[0020] Examples of the polyether block include polyether structures derived from polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMEG), etc. The polyether block may be a combination of units constituting these polyether structures.

[0021] The polyamide blocks and the polyether blocks may be randomly dispersed.

[0022] It is preferred that the number average molecular weight Mn of the polyamide block is 300 to 15,000. For example, the number average molecular weight Mn of the polyamide block can be 300, 3,000, 6,000, 9,000, 12,000, and 15,000. It is preferred that the number average molecular weight Mn of the polyether block is 100 to 6,000. For example, the number average molecular weight Mn of the polyether block can be 100, 1,000, 2,000, 3,000, 4,000, 5,000, and 6,000. It is more preferred that the number average molecular weight Mn of the polyamide block is 600 to 5,000. It is more preferred that the number average molecular weight Mn of the polyether block is 200 to 3,000.

[0023] In the present invention, the epoxy compound is an epoxy resin, preferably an alicyclic epoxy resin.

[0024] Preferably, the epoxy equivalent of the epoxy compound is 100 to 300 g / eq.

[0025] In the present invention, in the polyisocyanate or isocyanate prepolymer, the polyisocyanate is selected from one or more of aliphatic polyisocyanates and aliphatic cyclopolyisocyanates; preferably one of aliphatic diisocyanates and aliphatic cyclodiisocyanates, and more preferably 1,6-hexamethylene diisocyanate, pentamethylene diisocyanate, 1,10-decane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4 ,4-trimethylhexamethylene diisocyanate, 2,4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, isophorone diisocyanate; further preferably one or more of 1,6-hexamethylene diisocyanate, pentamethylene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

[0026] In the present invention, in the polyisocyanate or isocyanate prepolymer, the isocyanate prepolymer is selected from one or more of polyether type, polyester type, PCDL type and PCL type isocyanate prepolymers; the polyether type, polyester type, PCDL type and PCL type prepolymers are obtained by reacting polyether polyol, polyester polyol, polycarbonate polyol and polycaprolactone polyol with polyisocyanate respectively, and the NCO mass content in the prepolymer is preferably 0.2%-20%, and more preferably 0.2%-10%.

[0027] The polyether polyol is selected from: one or more of polyethylene glycol, polypropylene glycol, polytetramethylene glycol; the molecular weight of the polyether polyol is 500-4000 g / mol, more preferably 800-4000 g / mol.

[0028] The polyester polyol is selected from dicarboxylic acids and polyols having 2 to 12 carbon atoms, preferably 4 to 6 carbon atoms, such as one or more of ethylene glycol polyadipate, 1,4-butanediol polyadipate, ethylene glycol-1,4-butanediol polyadipate, 1,6-hexanediol-neopentyl glycol polyadipate, and 1,6-hexanediol-1,4-butanediol polyadipate diol. The number average molecular weight n of the polyester polyol is 500 to 10000 g / mol, particularly preferably 600 to 6000 g / mol, and more preferably 800-4000 g / mol.

[0029] The polycarbonate polyol uses a small molecule diol as an initiator and reacts with an aliphatic carbonate such as dimethyl carbonate, diethyl carbonate, vinyl carbonate, etc. to obtain a macromolecular polymer with terminal hydroxyl groups at both ends of the long-chain molecule and repeating unit carbonate groups on the main chain; common initiators include 1,2-ethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, etc.; preferably 1,2-ethylene glycol, 1,4-butanediol, neopentyl glycol; preferably the molecular weight range is 500-4000g / mol, more preferably 1000-4000g / mol.

[0030] The polycaprolactone polyol is prepared by ring-opening polymerization of ε-caprolactone in the presence of a catalyst and an initiator. Common initiators include ethylene glycol, diethylene glycol, neopentyl glycol, etc. The preferred molecular weight range is 500-4000 g / mol, and more preferably 800-4000 g / mol.

[0031] In the present invention, the cleaning of polyamide elastomer foaming material waste includes removing impurities and surface stains in the polyamide elastomer waste.

[0032] In the present invention, the method for recycling and reusing waste polyamide elastomer foaming materials comprises the step of drying the washed waste polyamide elastomer foaming materials before crushing.

[0033] In the present invention, the component used for melt blending with waste polyamide elastomer foam particles may further include antioxidants, ultraviolet absorbers, light stabilizers, colorants, etc., such as antioxidant 1098, antioxidant 1010, antioxidant 1076, antioxidant 168, ultraviolet absorber UV-234, light stabilizer UV-770, etc.

[0034] The melt index of the prepared recycled polyamide elastomer measured according to ISO 1133-1-A method at a temperature of 235°C and a load of 2.16 kg is 2 to 200 g / 10 min, preferably 3 to 150 g / 10 min, and more preferably 4 to 100 g / 10 min.

[0035] The prepared recycled polyamide elastomer can be used for re-foaming to prepare polyurethane elastomer foamed products or injection molding extrusion products.

[0036] A device for recycling and reusing waste polyamide elastomer foaming materials, comprising:

[0037] (1) a cleaning machine for cleaning discarded polyamide elastomer foaming materials from shoe midsoles to remove impurities and surface contaminants;

[0038] (2) A dryer connected to the discharge end of the cleaning machine and used for drying the cleaned waste polyamide elastomer foaming material.

[0039] (3) A pulverizer connected to the discharge end of the dryer, used for pulverizing the discarded polyamide elastomer foaming material to prepare polyamide elastomer foaming waste particles.

[0040] (4) A twin-screw extruder, used for melt-blending the crushed polyamide elastomer foaming waste particles with at least one low melt index polyamide elastomer, at least one epoxy compound, and at least one polyisocyanate or isocyanate prepolymer, and extruding to prepare the recycled polyamide elastomer.

[0041] Preferably, the extruder is divided into 11 temperature zones, the temperature range of the extruder is 80-250°C, the aspect ratio of the extruder screw is 30-120:1, preferably 40-75:1, the same-direction double-thread meshing screw, and the screw speed is 80-1500RPM.

[0042] The beneficial effects of the present invention are:

[0043] Realize efficient physical recycling of polyamide elastomer foam materials, significantly improve the recycling rate and reduce dependence on raw materials.

[0044] Through a special recycling process, the mechanical strength, heat resistance and other properties of the recycled materials are close to or better than those of the original materials, broadening the application scope of recycled materials in high value-added fields such as sports shoes and industrial products.

[0045] The recycling process is simple and does not use organic solvents, which effectively reduces energy consumption and environmental emissions, and is in line with the development trend of green manufacturing and circular economy. Specific implementation method:

[0046] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments.

[0047] Unless otherwise specified, the chemicals used in the examples and comparative examples of the present invention are all commercially available products with industrial grade purity.

[0048] The percentages used in the embodiments and comparative examples of the present invention are all mass percentages unless otherwise specified.

[0049] The performance testing methods of the foaming materials prepared in the embodiments and comparative examples of the present invention are as follows:

[0050] (1) Density: tested according to the method described in ASTM D792-2013;

[0051] (2) Melt index: tested by the method described in ISO 1133-1-A;

[0052] (3) Hardness: tested using a Shore durometer according to the method described in ASTM D2240;

[0053] (4) Tensile strength and elongation at break: tested according to the method described in ASTM D412;

[0054] (5) Tear resistance: tested according to the method described in ASTM D624;

[0055] (6) Material heat resistance test: The test was conducted using the method described in ASTM D3045, with an aging temperature of 113°C and an aging time of 168 h.

[0056] Preparation of polyamide elastomer foam waste particles:

[0057] (1) 20 kg of polyamide elastomer foam material processing scraps and polyamide elastomer foam shoe midsole waste are put into a cleaning machine and washed with water to remove impurities in the material and surface stains.

[0058] (2) The cleaned polyamide elastomer foam material scraps and waste are placed in a dryer and dried at 100° C. for 4 hours.

[0059] (3) The dried polyamide elastomer foaming material scraps and waste are put into a crusher and crushed to obtain 19.5 kg of polyamide elastomer foaming waste particles with a diameter of 0.2 cm to 1 cm.

[0060] Example 1

[0061] (1) 1.8 kg of the polyamide elastomer foam waste particles prepared above were mixed with 0.1 kg of nylon elastomer WHE-7211 (Wanhua Chemical Group Co., Ltd., melt index 22.3 g / 10 min, hardness 72D under 235°C / 2.16 kg test conditions), 100 g of epoxy resin ERH-186 (Shanghai Zhongsi Industrial Co., Ltd., epoxy equivalent 129 g / eq), 0.2 g HDI (Wanhua Chemical Group Co., Ltd.), 8g antioxidant 1010 (Tianjin Lianlong New Materials Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Materials Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Materials Co., Ltd.) were mixed and extruded into granules to prepare recycled polyamide elastomer particles PEBA-1. The temperatures of zones 1-11 of the twin-screw extruder (Nanjing Ruiya, aspect ratio 44) were 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, 185°C, and 180°C.

[0062] (2) The recycled polyamide elastomer particles prepared above were injection molded on an injection molding machine (Haitian, KMA600 / 100) to prepare the specimens required for various performance tests. After standing for 24 hours, various performance tests were performed. The test results are shown in Table 1.

[0063] Example 2

[0064] (1) 0.1 kg of the polyurethane elastomer foamed fertilizer particles prepared above were mixed with 1.8 kg of nylon elastomer WHE-4011 (Wanhua Chemical Group Co., Ltd., melt index 33 g / 10 min, hardness 95A under 235°C / 2.16 kg test conditions), 0.2 g of epoxy resin ERH-184 (Shanghai Zhongsi Industrial Co., Ltd., epoxy equivalent 175 g / eq), and 100 g of HMDI (Wanhua Chemical Group Co., Ltd.), 8g antioxidant 1010 (Tianjin Lianlong New Materials Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Materials Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Materials Co., Ltd.) were mixed and extruded into granules to prepare recycled polyamide elastomer particles PEBA-2. The temperatures of zones 1-11 of the twin-screw extruder (Nanjing Ruiya, aspect ratio 44) were 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, 185°C, and 180°C.

[0065] (2) The recycled polyamide elastomer particles prepared above were injection molded on an injection molding machine (Haitian, KMA600 / 100) to prepare the specimens required for various performance tests. After standing for 24 hours, various performance tests were performed. The test results are shown in Table 1.

[0066] Example 3

[0067] (1) 1.0 kg of the above-prepared polyurethane elastomer foam waste particles were mixed with 0.8 kg of nylon elastomer WHE-4011 (Wanhua Chemical Group Co., Ltd., melt index 33 g / 10 min, hardness 85A under 235°C / 2.16 kg test conditions), 70 g of epoxy resin ERH-186 (Shanghai Zhongsi Industrial Co., Ltd., epoxy equivalent 129 g / eq), and 30 g of WANNATE 3T3242 (isocyanate prepolymer, Wanhua Chemical Group Co., Ltd., NCO content 4.7%), 8g antioxidant 1010 (Tianjin Lianlong New Materials Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Materials Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Materials Co., Ltd.) were mixed and extruded and granulated to prepare recycled polyamide elastomer particles PEBA-3. The temperatures of zones 1-11 of the twin-screw extruder (Nanjing Ruiya, aspect ratio 44) were 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, 185°C, and 180°C.

[0068] (2) The recycled polyamide elastomer particles prepared above were injection molded on an injection molding machine (Haitian, KMA600 / 100) to prepare the specimens required for various performance tests. After standing for 24 hours, various performance tests were performed. The test results are shown in Table 1.

[0069] Example 4

[0070] (1) 0.8 kg of the above-prepared polyurethane elastomer foam waste particles were mixed with 1.0 kg of nylon elastomer WHE-5011 (Wanhua Chemical Group Co., Ltd., melt index 27.1 g / 10 min, hardness 50D under 235°C / 2.16 kg test conditions), 40 g of epoxy resin ERH-184 (Shanghai Zhongsi Industrial Co., Ltd., epoxy equivalent 175 g / eq), and 60 g of HDI (Wanhua Chemical Group Co., Ltd.), 8g antioxidant 1010 (Tianjin Lianlong New Materials Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Materials Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Materials Co., Ltd.) were mixed and extruded into granules to prepare recycled polyamide elastomer particles PEBA-4. The temperatures of zones 1-11 of the twin-screw extruder (Nanjing Ruiya, aspect ratio 44) were 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, 185°C, and 180°C.

[0071] (2) The recycled polyamide elastomer particles prepared above were injection molded on an injection molding machine (Haitian, KMA600 / 100) to prepare the specimens required for various performance tests. After standing for 24 hours, various performance tests were performed. The test results are shown in Table 1.

[0072] Example 5

[0073] (1) 1.4 kg of the above-prepared polyurethane elastomer foam waste particles were mixed with 0.4 kg of nylon elastomer WHE-4011 (Wanhua Chemical Group Co., Ltd., melt index 33 g / 10 min, hardness 95A under 235°C / 2.16 kg test conditions), 60 g of epoxy resin YX8034 (Mitsubishi Chemical, epoxy equivalent 290 g / eq), and 40 g of HMDI (Wanhua Chemical Group Co., Ltd.), 8g antioxidant 1010 (Tianjin Lianlong New Materials Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Materials Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Materials Co., Ltd.) were mixed and extruded into granules to prepare recycled polyamide elastomer particles PEBA-5. The temperatures of zones 1-11 of the twin-screw extruder (Nanjing Ruiya, aspect ratio 44) were 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, 185°C, and 180°C.

[0074] (2) The recycled polyamide elastomer particles prepared above were injection molded on an injection molding machine (Haitian, KMA600 / 100) to prepare the specimens required for various performance tests. After standing for 24 hours, various performance tests were performed. The test results are shown in Table 1.

[0075] Example 6

[0076] (1) 1.2 kg of the above-prepared polyurethane elastomer foam waste particles were mixed with 0.7 kg of nylon elastomer WHE-4012 (Wanhua Chemical Group Co., Ltd., melt index 24 g / 10 min, hardness 95A under 235 ° C / 2.16 kg test conditions), 40 g of epoxy resin ERH-186 (Shanghai Zhongsi Industrial Co., Ltd., epoxy equivalent 129 g / eq), 60 g of WANNATE 3T3242 (isocyanate prepolymer, Wanhua Chemical Group Co., Ltd., NCO content 4.7%), 8g antioxidant 1010 (Tianjin Lianlong New Materials Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Materials Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Materials Co., Ltd.) were mixed and extruded and granulated to prepare recycled polyamide elastomer particles PEBA-6. The temperatures of zones 1-11 of the twin-screw extruder (Nanjing Ruiya, aspect ratio 44) were 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, 185°C, and 180°C.

[0077] (2) The recycled polyamide elastomer particles prepared above were injection molded on an injection molding machine (Haitian, KMA600 / 100) to prepare the specimens required for various performance tests. After standing for 24 hours, various performance tests were performed. The test results are shown in Table 1.

[0078] Example 7

[0079] (1) 1.1 kg of the above-prepared polyurethane elastomer foam waste particles were mixed with 0.8 kg of nylon elastomer WHE-6011 (Wanhua Chemical Group Co., Ltd., melt index 22 g / 10 min, hardness 60D under 235°C / 2.16 kg test conditions), 30 g of epoxy resin ERH-184 (Shanghai Zhongsi Industrial Co., Ltd., epoxy equivalent 175 g / eq), and 70 g of HDI (Wanhua Chemical Group Co., Ltd.), 8g antioxidant 1010 (Tianjin Lianlong New Materials Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Materials Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Materials Co., Ltd.) were mixed and extruded into granules to prepare recycled polyamide elastomer particles PEBA-7. The temperatures of zones 1-11 of the twin-screw extruder (Nanjing Ruiya, aspect ratio 44) were 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, 185°C, and 180°C.

[0080] (2) The recycled polyamide elastomer particles prepared above were injection molded on an injection molding machine (Haitian, KMA600 / 100) to prepare the specimens required for various performance tests. After standing for 24 hours, various performance tests were performed. The test results are shown in Table 1.

[0081] Example 8

[0082] (1) 0.7 kg of the above-prepared polyurethane elastomer foam waste particles were mixed with 1.2 kg of nylon elastomer WHE-4011 (Wanhua Chemical Group Co., Ltd., melt index 33 g / 10 min, hardness 95A under 235°C / 2.16 kg test conditions), 100 g of epoxy resin YX8034 (Mitsubishi Chemical, epoxy equivalent 290 g / eq), 0.2 g HMDI (Wanhua Chemical Group Co., Ltd.), 8g antioxidant 1010 (Tianjin Lianlong New Materials Co., Ltd.), 4g ultraviolet absorber UV326 (Tianjin Lianlong New Materials Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Materials Co., Ltd.) were mixed and extruded into granules to prepare recycled polyamide elastomer particles PEBA-8. The temperatures of zones 1-11 of the twin-screw extruder (Nanjing Ruiya, aspect ratio 44) were 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, 185°C, and 180°C.

[0083] (2) The recycled polyamide elastomer particles prepared above were injection molded on an injection molding machine (Haitian, KMA600 / 100) to prepare the specimens required for various performance tests. After standing for 24 hours, various performance tests were performed. The test results are shown in Table 1.

[0084] Example 9

[0085] (1) 0.8 kg of the above-prepared polyurethane elastomer foam waste particles were mixed with 1.1 kg of nylon elastomer WHE-3011 (Wanhua Chemical Group Co., Ltd., melt index 66.3 g / 10 min, hardness 80A under 235°C / 2.16 kg test conditions), 50 g of epoxy resin ERH-186 (Shanghai Zhongsi Industrial Co., Ltd., epoxy equivalent 129 g / eq), and 50 g of WANNATE 3T3242 (isocyanate prepolymer, Wanhua Chemical Group Co., Ltd., NCO content 4.7%), 8g antioxidant 1010 (Tianjin Lianlong New Materials Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Materials Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Materials Co., Ltd.) were mixed and extruded and granulated to prepare recycled polyamide elastomer particles PEBA-9. The temperatures of zones 1-11 of the twin-screw extruder (Nanjing Ruiya, aspect ratio 44) were 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, 185°C, and 180°C.

[0086] (2) The recycled polyamide elastomer particles prepared above were injection molded on an injection molding machine (Haitian, KMA600 / 100) to prepare the specimens required for various performance tests. After standing for 24 hours, various performance tests were performed. The test results are shown in Table 1.

[0087] Comparative Example 1

[0088] (1) 1.9 kg of the above-prepared polyurethane elastomer foaming waste particles, 100 g of epoxy resin ERH-186 (Shanghai Zhongsi Industrial Co., Ltd., epoxy equivalent 129 g / eq), 0.2 g of HDI (Wanhua Chemical Group Co., Ltd.), 8 g of antioxidant 1010 (Tianjin Lianlong New Materials Co., Ltd.), 4 g of ultraviolet absorber UV234 (Tianjin Lianlong New Materials Co., Ltd.), and 4 g of light stabilizer UV770 (Tianjin Lianlong New Materials Co., Ltd.) were mixed and extruded into granules to prepare recycled polyamide elastomer particles PEBA-10. The temperatures of zones 1-11 of a twin-screw extruder (Nanjing Ruiya, aspect ratio 44) were 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, 185°C, and 180°C.

[0089] (2) The recycled polyamide elastomer particles prepared above were injection molded on an injection molding machine (Haitian, KMA600 / 100) to prepare the specimens required for various performance tests. After standing for 24 hours, various performance tests were performed. The test results are shown in Table 1.

[0090] Comparative Example 2

[0091] (1) 1.0 kg of the above-prepared polyurethane elastomer foam waste particles were mixed with 0.8 kg of nylon elastomer WHE-4011 (Wanhua Chemical Group Co., Ltd., melt index 33 g / 10 min, hardness 95A under 235°C / 2.16 kg test conditions), 70 g of epoxy resin ERH-186 (Shanghai Zhongsi Industrial Co., Ltd., epoxy equivalent 129 g / eq), 8 g of antioxidant 1010 (Tianjin Lianlong New Materials Co., Ltd.), 4 g of purple The ultraviolet absorber UV234 (Tianjin Lianlong New Materials Co., Ltd.) and 4g of light stabilizer UV770 (Tianjin Lianlong New Materials Co., Ltd.) were mixed and extruded into granules to prepare recycled polyamide elastomer particles PEBA-11. The temperatures of zones 1-11 of the twin-screw extruder (Nanjing Ruiya, aspect ratio 44) were 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, 185°C, and 180°C.

[0092] (2) The recycled polyamide elastomer particles prepared above were injection molded on an injection molding machine (Haitian, KMA600 / 100) to prepare the specimens required for various performance tests. After standing for 24 hours, various performance tests were performed. The test results are shown in Table 1.

[0093] Comparative Example 3

[0094] (1) 1.0 kg of the polyurethane elastomer foam waste particles prepared above were mixed with 0.8 kg of nylon elastomer WHE-4011 (Wanhua Chemical Group Co., Ltd., melt index 33 g / 10 min, hardness 95A under 235°C / 2.16 kg test conditions), 30 g of WANNATE 3T3242 (isocyanate prepolymer, Wanhua Chemical Group Co., Ltd., NCO content 4.7%), 4 g of ultraviolet absorber UV234 (Tianjin Lianlong New Materials Co., Ltd.), and 4 g of light stabilizer UV770 (Tianjin Lianlong New Materials Co., Ltd.), and then extruded and granulated to prepare recycled polyamide elastomer particles PEBA-12. The temperatures of zones 1-11 of a twin-screw extruder (Nanjing Ruiya, aspect ratio 44) were 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 195°C, 190°C, 185°C, and 180°C.

[0095] (2) The recycled polyamide elastomer particles prepared above were injection molded on an injection molding machine (Haitian, KMA600 / 100) to prepare the specimens required for various performance tests. After standing for 24 hours, various performance tests were performed. The test results are shown in Table 1.

[0096] Table 1

[0097]

[0098]

[0099] Unless otherwise defined, the terms used in the present invention have the meanings commonly understood by those skilled in the art.

[0100] The embodiments described in the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art may make various other substitutions, changes and improvements within the scope of the present invention. Therefore, the present invention is not limited to the above embodiments, but is only limited by the claims.

Claims

1. A method for recycling waste polyamide elastomer foaming materials, characterized in that: The following steps are included: 1) Cleaning polyamide elastomer foam material waste; 2) crushing the cleaned polyamide elastomer foaming material to prepare polyamide elastomer foaming waste particles; 3) The polyamide elastomer foaming waste particles are mixed with at least one low melt index polyamide elastomer, at least one epoxy compound, at least one polyisocyanate and / or isocyanate prepolymer, and then put into a twin-screw extruder for melt extrusion to prepare recycled polyamide elastomer particles for secondary use.

2. The method according to claim 1, characterized in that In step 3), the total mass of the mixture is taken as 100%, and the mass percentages are as follows: Polyamide elastomer foam waste particles 5% to 90%; preferably 15% to 80%; more preferably 25% to 70%, Low melt index polyamide elastomer 5% to 90%; preferably 15% to 80%; more preferably 25% to 70%, Epoxy compound 0.01% to 5%; preferably 0.05% to 4%; more preferably 0.1% to 3%, Polyisocyanate or isocyanate prepolymer 0.01% to 5%; preferably 0.05% to 4%; more preferably 0.1% to 3%.

3. The method according to claim 1 or 2, characterized in that: The low melt index polyamide elastomer has a melt index of 1 to 100 g / 10 min, preferably 2 to 75 g / 10 min, and more preferably 3 to 50 g / 10 min, measured according to ISO 1133-1-A method at a temperature of 235° C. and a load of 2.16 kg.

4. The method according to any one of claims 1 to 3, characterized in that The Shore hardness of the low melt index polyamide elastomer is selected from 50A to 80D, preferably 60A to 70D, and more preferably 70A to 60D.

5. The method according to any one of claims 1 to 4, characterized in that The epoxy compound is an epoxy resin, preferably an alicyclic epoxy resin; more preferably, the epoxy equivalent of the epoxy compound is 100 to 300 g / eq.

6. The method according to any one of claims 1 to 5, characterized in that In the polyisocyanate or isocyanate prepolymer, the polyisocyanate is selected from one or more of aliphatic and alicyclic polyisocyanates, preferably selected from one or more of pentamethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane 2,4-diisocyanate, and dicyclohexylmethane 4,4-diisocyanate; and / or, in the polyisocyanate or isocyanate prepolymer, the isocyanate prepolymer is selected from one or more of polyether type, polyester type, PCDL type and PCL type isocyanate prepolymers; the polyether type, polyester type, PCDL type and PCL type prepolymers are obtained by reacting polyether polyol, polyester polyol, polycarbonate polyol and polycaprolactone polyol with polyisocyanate, respectively, and the NCO mass content in the prepolymer is preferably 0.2%-20%, and more preferably 0.2%-10%.

7. The method according to any one of claims 1 to 6, characterized in that The component used for melt blending with the polyamide elastomer foaming waste particles further includes one or more of an antioxidant, an ultraviolet absorber, a light stabilizer, and a colorant, such as one or more of antioxidant 1098, antioxidant 1010, antioxidant 1076, antioxidant 168, ultraviolet absorber UV-234, ultraviolet absorber UV-312, and light stabilizer UV-770.

8. The method according to any one of claims 1 to 7, characterized in that The melt index of the prepared recycled polyamide elastomer measured according to ISO 1133-1-A method at a temperature of 235° C. and a load of 2.16 kg is 2 to 200 g / 10 min, preferably 3 to 150 g / 10 min, and more preferably 4 to 100 g / 10 min.

9. The method according to any one of claims 1 to 8, characterized in that The extruder is divided into 11 temperature zones, the temperature range of the extruder is 80-250°C, the aspect ratio of the extruder screw is 30-120:1, preferably 40-75:1 co-directional double-thread meshing screw, and the screw speed is 80-1500RPM.

10. Use of the polyamide elastomer particles prepared by the method according to any one of 1 to 9 for re-foaming to prepare polyurethane elastomer foamed products or injection molded extruded products.

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