A method for recycling waste polyamide elastomer foamed material

Abstract

The application discloses a kind of high-efficiency recycling methods for waste polyamide elastomer foamed material, to ensure product performance while realizing the recycling of waste polyamide elastomer foamed material by innovative cleaning, crushing, melt blending regeneration technology, effectively reduce resource waste and environmental burden.

Description

Technical fields:

[0001] This invention relates to recycling technology for polyamide elastomer foam materials, and in particular to an environmentally friendly, economical, and efficient recycling method applicable to the treatment of various polyamide elastomer foam material wastes, so as to achieve resource recycling. Technical background:

[0002] Polyamide elastomers are a class of elastomer materials composed of high-rigidity polyamides as the hard segments and flexible polyethers as the soft segments. They possess advantages such as low density, a wide hardness range, high resilience, fatigue resistance, oil resistance, and chemical resistance. In recent years, polyamide elastomers have gained significant attention in the field of foam materials. Compared to thermoplastic elastomer foam materials such as polyurethane elastomers, polyolefin elastomers, or ethylene-vinyl acetate elastomers, foam materials prepared from polyamide elastomers exhibit superior resilience and lower density, leading to their widespread application in sports footwear materials, particularly in high-end running shoes.

[0003] Polyamide elastomer foam materials generate a large amount of foam material waste during processing and after use, which not only wastes resources but also causes environmental pollution. The effective recycling of this waste has become an urgent problem to be solved. Traditional physical recycling methods often face challenges such as complex processes and degradation of the physical properties of recycled materials, which limit the recycling rate and reuse value of these high-value materials. Summary of the Invention:

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

[0005] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows:

[0006] A method for recycling waste polyamide elastomer foam material includes the following steps:

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

[0008] 2) Crush the cleaned polyamide elastomer foam material to prepare polyamide elastomer foam waste particles;

[0009] 3) Mix polyamide elastomer foam 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 then feed the mixture into a twin-screw extruder for melt extrusion to prepare reusable recycled polyamide elastomer particles.

[0010] As a preferred embodiment, the total mass of the mixture is calculated as 100%, according to the following mass percentages:

[0011] The content of polyamide elastomer foam waste particles is 5%–90%; preferably 15%–80%; more preferably 25%–70%.

[0012] The low melt index polyamide elastomer comprises 5% to 90%; preferably 15% to 80%; more preferably 25% to 70%.

[0013] The epoxy compound comprises 0.01% to 5%; preferably 0.05% to 4%; more preferably 0.1% to 3%.

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

[0015] This invention proposes an efficient recycling method for waste polyamide elastomer foam materials. The method utilizes innovative washing, crushing, and melt-blending regeneration technologies. Waste polyamide elastomer foam materials are washed, crushed, and then mixed with at least one low melt index polyamide elastomer, at least one polyisocyanate or isocyanate prepolymer, and at least one epoxy resin before melt extrusion to prepare reusable recycled polyamide elastomer granules. The main technical advantage of this invention lies in the simultaneous introduction of polyisocyanate and epoxy resin during the melt-blending recycling process. This chain-extending effect is achieved, and the isocyanate groups react with epoxy groups, introducing polyazole ketone groups into the polyamide elastomer, thereby improving its heat resistance.

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

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

[0018] In this invention, the polyamide elastomer generally refers to a copolymer having polyamide blocks (hard segments) and polyether blocks (soft segments).

[0019] Examples of polyamide blocks include polyamide structures derived from poly(ε-decanoamide) (Nylon 6), poly(butylene adipamide) (Nylon 46), poly(hexamethylene adipamide) (Nylon 66), poly(hexamethylene decanediamide) (Nylon 610), poly(hexamethylene dodecanoyl)diamine (Nylon 612), poly(undecanediamine) (Nylon 116), polyundecanoamide (Nylon 11), poly(dodecanoamide) (Nylon 12), poly(hexamethylene isophthalamide) (Nylon 6I), poly(hexamethylene terephthalamide) (Nylon 6T), poly(nonadiamine terephthalamide) (Nylon 9T), and poly(m-phenylene adipamide) (Nylon MXD6). Polyamide blocks can be combinations of units that constitute these polyamide structures.

[0020] Examples of polyether blocks include polyether structures derived from polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMEG), etc. A polyether block can be a combination of units that constitute these polyether structures.

[0021] Polyamide blocks and polyether blocks can be randomly dispersed.

[0022] Preferably, the number-average molecular weight (Mn) of the polyamide blocks is from 300 to 15,000. For example, the number-average molecular weight (Mn) of the polyamide blocks can be 300, 3,000, 6,000, 9,000, 12,000, and 15,000. Preferably, the number-average molecular weight (Mn) of the polyether blocks is from 100 to 6,000. For example, the number-average molecular weight (Mn) of the polyether blocks can be 100, 1,000, 2,000, 3,000, 4,000, 5,000, and 6,000. More preferably, the number-average molecular weight (Mn) of the polyamide blocks is from 600 to 5,000. Even more preferably, the number-average molecular weight (Mn) of the polyether blocks is from 200 to 3,000.

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

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

[0025] In this invention, the polyisocyanate or isocyanate prepolymer is selected from one or more aliphatic polyisocyanates and alicyclic polyisocyanates; preferably, it is one of aliphatic diisocyanates and alicyclic diisocyanates, and more preferably, it is 1,6-hexamethylene diisocyanate, pentamethylene diisocyanate, 1,10-decanediisocyanate, 1,3-cyclohexanediisocyanate, 1,4-cyclohexanediisocyanate, 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; more 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 this invention, the polyisocyanate or 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 polyols, polyester polyols, polycarbonate polyols, and polycaprolactone polyols with polyisocyanates, respectively; the NCO content in the prepolymer is preferably 0.2%-20%, more preferably 0.2%-10%.

[0027] The polyether polyol is selected from one or more of polyethylene oxide diol, polypropylene oxide diol, and polytetramethylene diol; 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 diols. The number average molecular weight n of the polyester polyol is 500 to 10,000 g / mol, particularly preferably 600 to 6,000 g / mol, and more preferably 800 to 4,000 g / mol.

[0029] The polycarbonate polyol is prepared by reacting aliphatic carbonates such as dimethyl carbonate, diethyl carbonate, and ethylene carbonate with small molecule diols as initiators to obtain a macromolecular polymer with terminal hydroxyl groups at both ends and repeating carbonate groups on the main chain. Commonly used initiators include 1,2-ethylene glycol, 1,4-butanediol, neopentyl glycol, and 1,6-hexanediol. Preferably, it is 1,2-ethylene glycol, 1,4-butanediol, or neopentyl glycol. Preferably, the molecular weight range is 500-4000 g / mol, and more preferably 1000-4000 g / mol.

[0030] The polycaprolactone polyol is prepared by ring-opening polymerization of ε-caprolactone in the presence of a catalyst and an initiator. Commonly used 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 this invention, the cleaning of polyamide elastomer foam material waste includes removing impurities and surface stains from the polyamide elastomer waste.

[0032] In this invention, the method for recycling and reusing waste polyamide elastomer foam material includes a step of drying the cleaned waste polyamide elastomer foam material before crushing.

[0033] In this 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 at a temperature of 235°C and a load of 2.16 kg, is 2–200 g / 10 min, preferably 3–150 g / 10 min, and more preferably 4–100 g / 10 min.

[0035] The prepared recycled polyamide elastomer can be used to re-foam polyurethane elastomer foam products or injection-molded extruded products.

[0036] A device for recycling and reusing waste polyamide elastomer foam material includes:

[0037] (1) A cleaning machine for cleaning waste polyamide elastomer foam material in shoe midsoles to remove impurities and surface contaminants;

[0038] (2) A dryer, connected to the discharge end of the cleaning machine, is used to dry the cleaned waste polyamide elastomer foam material.

[0039] (3) A pulverizer connected to the discharge end of the dryer is used to pulverize waste polyamide elastomer foam material and prepare polyamide elastomer foam waste particles.

[0040] (4) A twin-screw extruder is used to melt-blend pulverized polyamide elastomer foam 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 then extrude to prepare recycled polyamide elastomer.

[0041] Preferably, the extruder is divided into 11 temperature zones, the extruder temperature range is 80-250℃, the extruder screw length-to-diameter ratio is 30-120:1, preferably a co-directional double-threaded meshing screw of 40-75:1, and the screw speed is 80-1500RPM.

[0042] The beneficial effects of this invention are as follows:

[0043] This technology enables efficient physical recycling of polyamide elastomer foam materials, significantly improving the recycling rate and reducing reliance on raw materials.

[0044] Through special recycling processes, the mechanical strength, heat aging resistance, and other properties of recycled materials are made to be close to or better than those of virgin materials, thus broadening the application scope of recycled materials in high-value-added fields such as sports shoe materials and industrial products.

[0045] The recycling process is simple and does not use organic solvents, effectively reducing energy consumption and environmental emissions, which aligns with the development trends of green manufacturing and circular economy. Detailed Implementation

[0046] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

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

[0048] Unless otherwise specified, all percentages used in the embodiments and comparative examples of this invention are mass percentages.

[0049] The performance testing methods for the foamed 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 flow index: Tested according to the method described in ISO 1133-1-A;

[0052] (3) Hardness: The Shore hardness tester was used to test the hardness 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 shall be conducted according to the method described in ASTM D3045, with an aging temperature of 113℃ and an aging time of 168h.

[0056] Preparation of polyamide elastomer foam waste granules:

[0057] (1) Put 20Kg of polyamide elastomer foam material processing scraps and polyamide elastomer foam shoe midsole waste into the cleaning machine, wash with water to remove impurities and surface stains from the materials.

[0058] (2) Put the cleaned polyamide elastomer foam material scraps and waste into the dryer and dry them at 100°C for 4 hours.

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

[0060] Example 1

[0061] (1) 1.8 kg of the polyamide elastomer foaming 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 test conditions of 235℃ / 2.16 kg), 100 g of epoxy resin ERH-186 (Shanghai Zhongsi Industrial Co., Ltd., epoxy equivalent 129 g / eq), and 0.2 g of... HDI (Wanhua Chemical Group Co., Ltd.), 8g antioxidant 1010 (Tianjin Lianlong New Material Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Material Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Material Co., Ltd.) were mixed and extruded to granulate recycled polyamide elastomer particles PEBA-1. The temperature in zones 1-11 of the twin-screw extruder (Nanjing Ruya, L / D ratio 44) was 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, 180℃.

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

[0063] Example 2

[0064] (1) Mix 0.1 kg of the polyurethane elastomer foamed fertilizer granules prepared above with 1.8 kg of nylon elastomer WHE-4011 (Wanhua Chemical Group Co., Ltd., melt index 33 g / 10 min, hardness 95A under test conditions of 235℃ / 2.16 kg), 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 Material Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Material Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Material Co., Ltd.) were mixed and extruded to granulate recycled polyamide elastomer particles PEBA-2. The temperature in zones 1-11 of the twin-screw extruder (Nanjing Ruya, L / D ratio 44) was 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, 180℃.

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

[0066] Example 3

[0067] (1) Mix 1.0 kg of the polyurethane elastomer foaming waste particles prepared above with 0.8 kg of nylon elastomer WHE-4011 (Wanhua Chemical Group Co., Ltd., melt index 33 g / 10 min, hardness 85A under test conditions of 235℃ / 2.16 kg), 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 Material Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Material Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Material Co., Ltd.) were mixed and extruded to granulate recycled polyamide elastomer particles PEBA-3. The temperature in zones 1-11 of the twin-screw extruder (Nanjing Ruya, length-to-diameter ratio 44) was 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, 180℃.

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

[0069] Example 4

[0070] (1) Mix 0.8 kg of the polyurethane elastomer foaming waste particles prepared above with 1.0 kg of nylon elastomer WHE-5011 (Wanhua Chemical Group Co., Ltd., melt index 27.1 g / 10 min, hardness 50 D under test conditions of 235℃ / 2.16 kg), 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 Material Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Material Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Material Co., Ltd.) were mixed and extruded to granulate recycled polyamide elastomer particles PEBA-4. The temperature in zones 1-11 of the twin-screw extruder (Nanjing Ruya, L / D ratio 44) was 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, 180℃.

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

[0072] Example 5

[0073] (1) Mix 1.4 kg of the polyurethane elastomer foaming waste particles prepared above with 0.4 kg of nylon elastomer WHE-4011 (Wanhua Chemical Group Co., Ltd., melt index 33 g / 10 min, hardness 95A under test conditions of 235℃ / 2.16 kg), 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 Material Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Material Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Material Co., Ltd.) were mixed and extruded to granulate recycled polyamide elastomer particles PEBA-5. The temperature in zones 1-11 of the twin-screw extruder (Nanjing Ruya, L / D ratio 44) was 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, 180℃.

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

[0075] Example 6

[0076] (1) 1.2 kg of the polyurethane elastomer foaming waste particles prepared above 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 test conditions of 235℃ / 2.16 kg), 40 g of epoxy resin ERH-186 (Shanghai Zhongsi Industrial Co., Ltd., epoxy equivalent 129 g / eq), and 60 g of WANNATE. 3T3242 (isocyanate prepolymer, Wanhua Chemical Group Co., Ltd., NCO content 4.7%), 8g antioxidant 1010 (Tianjin Lianlong New Material Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Material Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Material Co., Ltd.) were mixed and extruded to granulate recycled polyamide elastomer particles PEBA-6. The temperature in zones 1-11 of the twin-screw extruder (Nanjing Ruya, L / D ratio 44) was 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, 180℃.

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

[0078] Example 7

[0079] (1) Mix 1.1 kg of the polyurethane elastomer foaming waste particles prepared above with 0.8 kg of nylon elastomer WHE-6011 (Wanhua Chemical Group Co., Ltd., melt index 22 g / 10 min, hardness 60 D under test conditions of 235℃ / 2.16 kg), 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 Material Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Material Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Material Co., Ltd.) were mixed and extruded to granulate recycled polyamide elastomer particles PEBA-7. The temperature in zones 1-11 of the twin-screw extruder (Nanjing Ruya, L / D ratio 44) was 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, 180℃.

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

[0081] Example 8

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

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

[0084] Example 9

[0085] (1) Mix 0.8 kg of the polyurethane elastomer foaming waste particles prepared above with 1.1 kg of nylon elastomer WHE-3011 (Wanhua Chemical Group Co., Ltd., melt index 66.3 g / 10 min, hardness 80A under test conditions of 235℃ / 2.16 kg), 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 Material Co., Ltd.), 4g ultraviolet absorber UV234 (Tianjin Lianlong New Material Co., Ltd.), and 4g light stabilizer UV770 (Tianjin Lianlong New Material Co., Ltd.) were mixed and extruded to granulate recycled polyamide elastomer particles PEBA-9. The temperature in zones 1-11 of the twin-screw extruder (Nanjing Ruya, L / D ratio 44) was 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, 180℃.

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

[0087] Comparative Example 1

[0088] (1) 1.9 kg of the polyurethane elastomer foaming waste particles prepared above, 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 Material Co., Ltd.), 4 g of ultraviolet absorber UV234 (Tianjin Lianlong New Material Co., Ltd.), and 4 g of light stabilizer UV770 (Tianjin Lianlong New Material Co., Ltd.) were mixed and extruded to granulate and prepare recycled polyamide elastomer particles PEBA-10. The temperature of zones 1-11 of the twin-screw extruder (Nanjing Ruya, length-to-diameter ratio 44) was 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, 180℃.

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

[0090] Comparative Example 2

[0091] (1) Mix 1.0 kg of the polyurethane elastomer foaming waste particles prepared above with 0.8 kg of nylon elastomer WHE-4011 (Wanhua Chemical Group Co., Ltd., melt index 33 g / 10 min, hardness 95A under test conditions of 235℃ / 2.16 kg), 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 Material Co., Ltd.), and 4 g of purple Recycled polyamide elastomer particles PEBA-11 were prepared by extrusion granulation after mixing UV234 (Tianjin Lianlong New Material Co., Ltd.) and 4g of UV770 (Tianjin Lianlong New Material Co., Ltd.). The temperature of zones 1-11 of the twin-screw extruder (Nanjing Ruya, L / D ratio 44) was 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, and 180℃.

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

[0093] Comparative Example 3

[0094] (1) 1.0 kg of the polyurethane elastomer foaming 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 test conditions of 235℃ / 2.16 kg), 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 Material Co., Ltd.), and 4 g of light stabilizer UV770 (Tianjin Lianlong New Material Co., Ltd.) and then extruded and granulated to prepare recycled polyamide elastomer particles PEBA-12. The temperature of zones 1-11 of the twin-screw extruder (Nanjing Ruya, length-to-diameter ratio 44) was 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, 180℃.

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

[0096] Table 1

[0097]

[0098]

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

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

Claims

1. A method for recycling waste polyamide elastomer foam material, characterized in that, It includes the following steps: 1) Cleaning waste polyamide elastomer foam material; 2) Crush the cleaned polyamide elastomer foam material to prepare polyamide elastomer foam waste particles; 3) The polyamide elastomer foam 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 fed into a twin-screw extruder for melt extrusion to prepare recycled polyamide elastomer particles for secondary use. In step 3), the total mass of the mixture is taken as 100%, and the following mass percentages are used: Polyamide elastomer foaming waste particles account for 5%~90%. Low melt index polyamide elastomers: 5%~90% Epoxy compounds 0.01%~5%, Polyisocyanates or isocyanate prepolymers: 0.01%~5%; The low melt flow index polyamide elastomer described herein was measured to be 1~100 g / 10 min at a temperature of 235 °C and a load of 2.16 kg according to ISO 1133-1-A method.

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 following mass percentages are used: Polyamide elastomer foaming waste particles account for 15%~80%. Low melt index polyamide elastomer 15%~80%, Epoxy compounds 0.05%~4%, Polyisocyanates or isocyanate prepolymers: 0.05% to 4%.

3. The method according to claim 2, characterized in that, In step 3), the total mass of the mixture is taken as 100%, and the following mass percentages are used: Polyamide elastomer foaming waste particles account for 25%~70%. Low melt index polyamide elastomer 25%~70%, Epoxy compounds 0.1%~3%, 0.1% to 3% of polyisocyanates or isocyanate prepolymers.

4. The method according to claim 1, characterized in that, The low melt flow index polyamide elastomer described herein was measured to be 2~75 g / 10 min at a temperature of 235 °C and a load of 2.16 kg according to ISO 1133-1-A method.

5. The method according to claim 4, characterized in that, The low melt flow index polyamide elastomer described herein was measured to be 3~50 g / 10 min at a temperature of 235 °C and a load of 2.16 kg according to ISO 1133-1-A method.

6. The method according to any one of claims 1-5, characterized in that, The Shore hardness of the low melt flow index polyamide elastomer is 50A~80D.

7. The method according to claim 6, characterized in that, The Shore hardness of the low melt flow index polyamide elastomer is 60A~70D.

8. The method according to claim 7, characterized in that, The Shore hardness of the low melt flow index polyamide elastomer is 70A~60D.

9. The method according to any one of claims 1-5, characterized in that, The epoxy compound mentioned above is an epoxy resin.

10. The method according to claim 9, characterized in that, The epoxy compound is an alicyclic epoxy resin.

11. The method according to claim 10, characterized in that, The epoxy equivalent of the epoxy compound is 100~300 g / eq.

12. The method according to any one of claims 1-5, characterized in that, In the aforementioned polyisocyanate or isocyanate prepolymer, the polyisocyanate is selected from one or more aliphatic and alicyclic polyisocyanates; and / or, in the aforementioned polyisocyanate or isocyanate prepolymer, the isocyanate prepolymer is selected from one or more 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 polyols, polyester polyols, polycarbonate polyols, and polycaprolactone polyols with polyisocyanates, respectively.

13. The method according to claim 12, characterized in that, The polyisocyanate is selected from one or more of pentamethylene diisocyanate, hexamethylene diisocyanate, isoflurone diisocyanate, dicyclohexylmethane 2,4-diisocyanate, and dicyclohexylmethane 4,4-diisocyanate.

14. The method according to claim 12, characterized in that, The NCO content in the prepolymer is 0.2%-20% by mass.

15. The method according to claim 14, characterized in that, The NCO content in the prepolymer is 0.2%-10% by mass.

16. The method according to any one of claims 1-5, characterized in that, In step 3), the component used for melt blending with polyamide elastomer foam waste particles also includes one or more of antioxidants, ultraviolet absorbers, light stabilizers, and colorants.

17. The method according to claim 16, characterized in that, In step 3), the component used for melt blending with polyamide elastomer foam waste particles also includes 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.

18. The method according to any one of claims 1-5, characterized in that, The melt index of the prepared recycled polyamide elastomer was measured according to ISO 1133-1-A at a temperature of 235℃ and a load of 2.16Kg, and was 2~200g / 10min.

19. The method according to claim 18, characterized in that, The melt index of the prepared recycled polyamide elastomer was measured according to ISO 1133-1-A at a temperature of 235℃ and a load of 2.16Kg, and was 3~150g / 10min.

20. The method according to claim 19, characterized in that, The melt index of the prepared recycled polyamide elastomer was measured according to ISO 1133-1-A at a temperature of 235℃ and a load of 2.16Kg, and was 4~100g / 10min.

21. The method according to any one of claims 1-5, characterized in that, The extruder is divided into 11 temperature zones, with a temperature range of 80-250℃. The extruder screw is a co-directional double-threaded meshing screw with a length-to-diameter ratio of 30 to 120:1 and a screw speed of 80-1500 RPM.

22. The method according to claim 21, characterized in that, The length-to-diameter ratio of the extruder screw is 40 to 75:

1.

23. Use of the polyamide elastomer particles prepared by any one of 1-22 for re-foaming to prepare polyurethane elastomer foamed articles or injection-molded extruded articles.

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