Process for preparing insoles by utilizing recycled leftover materials
By crushing, pickling and heating kneading of the recovered scraps, combined with the molding and foaming process of specific pretreatment agents and other materials, the problem of easy cracking insoles for recycling scraps is solved in the long-term use. The resulting insoles have excellent elasticity and bending resistance.
Patent Information
- Application Number
- CN202510443503.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-10
- Publication Date
- 2025-07-18
AI Technical Summary
In the prior art, insoles prepared by recycling scraps are prone to crease or breaking during long-term use, especially in scenarios such as sports shoes that require better elasticity and bending resistance.
The scraps are recovered by crushing and pickling treatment, and pretreatment agent containing long-chain ether group is added for heating and kneading, and then melt-extruded with polymethylvinyl ether/maleic anhydride copolymer, polyurethane elastomer, tetrapolymer ricinoleate, filler, foaming agent and antioxidant, and molded and foamed to obtain insole.
It significantly improves the elasticity, sweat resistance and bending resistance of the insole, extends the service life, and avoids crease or fracture problems during long-term use.
Smart Images
Figure BDA0005351828870000051 
Figure BDA0005351828870000061 
Figure BDA0005351828870000071
Abstract
Description
Technical Field
[0001] The present application relates to the field of recycling and processing of insole materials. More specifically, it relates to a process for preparing insoles using recycled scraps. Background Art
[0002] During the production of insoles, a molding and foaming process is required. The insole material foams and forms in the molding die, and scraps are generated in the edge area. If the scraps are treated as waste, it is easy to increase the waste treatment cost and raw material cost. Therefore, the scraps are generally recycled and reused, which can save production costs and reduce the energy consumption of waste treatment.
[0003] Insole materials are generally polyurethane materials. After molding and foaming, the recycled scraps are prone to compatibility problems with the new insole materials, resulting in a decrease in the mechanical strength of the prepared insoles. In the prior art, generally, after the scraps are crushed, some modifiers such as chitosan and silane coupling agents are added to modify the scraps. Although the compatibility between the scraps and the new insole materials can be improved and the mechanical strength can be improved, the prepared insoles have poor folding resistance after being used for a period of time, are prone to creases or even fractures, and reduce the applicability of the insoles in shoes such as sports shoes that require good elasticity and folding resistance. Summary of the Invention
[0004] In order to solve the problem that the insoles prepared using recycled scraps are prone to creases or fractures after long-term use when applied to sports shoes, etc., the present application provides a process for preparing insoles using recycled scraps.
[0005] The present application provides a process for preparing insoles using recycled scraps, adopting the following technical scheme: A process for preparing insoles using recycled scraps, comprising the following steps: S1. Crush the recycled scraps, perform pickling, water washing and drying to obtain scrap particles; S2. Add a pretreatment agent accounting for 2 - 4wt% of the scrap particles and perform heating and kneading to obtain pretreated scraps; S3. Melt-extrude, granulate, and perform molding and foaming on the pretreated scraps, poly(methyl vinyl ether / maleic anhydride) copolymer, polyurethane elastomer, tetraricinoleate, filler, foaming agent, foaming aid, and antioxidant to obtain insoles; The pretreatment agent in the step S2 is a substance containing a long-chain ether group.
[0006] By adopting the above technical solution, the process crushes and pickles the recycled scraps to remove some impurities in the recycled scraps, obtaining scrap particles and improving the raw material purity for subsequent insole processing. Then, a pretreatment agent containing long-chain ether groups is used to heat and knead the scrap particles, enabling the pretreatment agent to fully penetrate into the interior of the scraps, significantly enhancing the softness and compatibility of the scraps, and obtaining pretreated scraps. Subsequently, the pretreated scraps are melted with poly(methyl vinyl ether / maleic anhydride) copolymer, polyurethane elastomer, tetraricinoleate, filler, foaming agent, foaming aid, and antioxidant. Without the need to additionally add a compatibilizer, the various materials can be uniformly mixed and compatible. Then, it is molded by compression foaming. The obtained insole has excellent elasticity, sweat resistance, and bending resistance, can meet the requirements of high-demand scenarios such as sports shoes, avoids the problems of creases or fractures during long-term use, and extends the service life of the insole.
[0007] Preferably, the pretreatment agent in step S2 is composed of C12-C14 alkyl glycidyl ether and polyethylene glycol monoallyl ether with a weight ratio of 1:(1-2).
[0008] By adopting the above technical solution, using C12-C14 alkyl glycidyl ether and polyethylene glycol monoallyl ether with a relatively optimal weight ratio as the pretreatment agent for heating and kneading, C12-C14 alkyl glycidyl ether and polyethylene glycol monoallyl ether have a soft long-chain ether structure, can fully infiltrate and penetrate the scrap particles, enhance the flexibility and compatibility of the scrap particles, and can form a dense intertwined structure with the polyurethane elastomer system during the subsequent melting process, improving the flexibility of the obtained insole, and further improving the elasticity, sweat resistance, and bending resistance.
[0009] Preferably, the particle size of the crushed recycled scraps in step S1 is 0.2-2 mm.
[0010] By adopting the above technical solution, the recycled scraps with a relatively optimal crushed particle size can improve the pickling efficiency, and at the same time can improve the dispersion uniformity and melting compatibility during the subsequent processing.
[0011] Preferably, the kneading temperature in step S2 is 80-100 °C.
[0012] By adopting the above technical solution, a relatively optimal kneading temperature can effectively promote the dispersion of the pretreatment agent in the scrap particles and improve the penetration uniformity of the pretreatment agent in the scrap particles.
[0013] Preferably, the weight parts usage amounts of the respective components in step S3 are as follows: Pretreated scraps 30-50 parts Polyurethane elastomer 60-80 parts 6 - 12 parts of polymethyl vinyl ether / maleic anhydride copolymer 10 - 20 parts of filler 4 - 8 parts of tetraricinoleate 4 - 6 parts of foaming agent 3 - 5 parts of foaming aid 1 - 3 parts of antioxidant.
[0014] By adopting the above technical solution, further optimizing the dosage of each component, the prepared insole can use the scraps to a large extent, and at the same time can obtain better elasticity and bending resistance. The pretreated scraps and polyurethane elastomer with better weight ratio are compounded. The polyurethane elastomer endows the insole with excellent elasticity, flexibility and wear resistance. However, there is a problem of similarity between the single polyurethane elastomer and the pretreated scraps and filler. Therefore, under the synergistic effect of the pretreatment agent, polymethyl vinyl ether / maleic anhydride copolymer and tetraricinoleate, the above three can form a uniform and dense intertwined molecular structure, and can form a uniform foaming system after compression molding and foaming, thereby improving the elasticity, sweat resistance and bending resistance of the insole.
[0015] Preferably, the filler is any one or combination of silica, calcium carbonate, and diatomaceous earth.
[0016] By adopting the above technical solution, the above filler can preferably improve the wear resistance and tear strength of the insole.
[0017] Preferably, the foaming agent is azodicarbonamide, and the foaming aid is zinc oxide.
[0018] By adopting the above technical solution, using azodicarbonamide as the foaming agent and zinc oxide as the foaming aid, the foaming aid can adjust the decomposition temperature of the foaming agent, improve the foaming uniformity and stability of compression molding and foaming, and improve the comprehensive performance of the prepared insole.
[0019] Preferably, the antioxidant is a hindered phenol antioxidant and / or a phosphite antioxidant.
[0020] By adopting the above technical solution, using a hindered phenol antioxidant and / or a phosphite antioxidant can effectively improve the antioxidant performance of the insole, prevent material aging caused by long-term use, and further extend the service life of the insole.
[0021] Preferably, the melting temperature in the S3 step is 160 - 170 °C.
[0022] By adopting the above technical solution, a relatively optimal melting temperature can enable the full mixing of the pretreated scraps and other raw materials, ensuring good fluidity of the material within this temperature range while avoiding material degradation or performance decline caused by excessive temperature.
[0023] Preferably, the molding temperature in the step S3 is 180 - 190 °C, and the molding time is 10 - 15 min.
[0024] By adopting the above technical solution, relatively optimal molding temperature and time can enable the foaming agent to foam uniformly, improving the foaming uniformity and stability of the internal structure of the insole. The finally prepared insole has better elasticity, sweat resistance and bending resistance, and is not prone to creases or fractures during long-term use.
[0025] In summary, the present application includes at least one of the following beneficial technical effects: 1. By crushing and pickling the recycled scraps, some impurities in the recycled scraps are removed to obtain scrap particles. Then, a pretreatment agent containing a long-chain ether group is used to heat and knead the scrap particles, enabling the pretreatment agent to fully penetrate into the interior of the scraps, significantly improving the softness and compatibility of the scraps, and obtaining pretreated scraps. Then, the pretreated scraps are melted with poly(methyl vinyl ether / maleic anhydride) copolymer, polyurethane elastomer, tetra ricinoleate, filler, foaming agent, foaming aid and antioxidant. There is no need to additionally add a compatibilizer, enabling the uniform mixing and compatibility of each material. Then, it is molded by compression molding and foaming to obtain an insole with excellent elasticity, sweat resistance and bending resistance, which can meet the requirements of high-demand scenarios such as sports shoes, avoiding the problems of creases or fractures during long-term use and extending the service life of the insole.
[0026] 2. Using C12 - C14 alkyl glycidyl ether and polyethylene glycol monoallyl ether in a relatively optimal weight ratio as the pretreatment agent for heating and kneading, C12 - C14 alkyl glycidyl ether and polyethylene glycol monoallyl ether have a soft long-chain ether structure, which can fully infiltrate and penetrate the scrap particles, improving the flexibility and compatibility of the scrap particles, enhancing the flexibility of the prepared insole, and further improving the elasticity, sweat resistance and bending resistance.
[0027] 3. By compounding the pretreated scraps and polyurethane elastomer in a relatively optimal weight ratio, and compounding with poly(methyl vinyl ether / maleic anhydride) copolymer, tetra ricinoleate, filler, foaming agent, foaming aid and antioxidant, the prepared insole has good flexibility, elasticity, sweat resistance and bending resistance. Detailed implementation mode
[0028] The sources and specifications of some raw materials of the present application are as follows. The raw materials used in the preparation examples and examples of the present application can all be obtained commercially, including but not limited to the raw materials of the following models and manufacturers. Raw materials with the same performance can all be used: 1. Recycled scraps: polyurethane insole scraps, hardness 60 - 65A, 0.6 - 0.9 g / cm 3 ; 2. Poly(methyl vinyl ether / maleic anhydride) copolymer: Shuer Biology, CAS No. 9011 - 16 - 9, content 99%; 3. Polyurethane elastomer: BASF Elastollan 1185A; 4. Tetrameric castor oil acid ester: average molecular weight about 1138, acid value 50 - 62 mgKOH / g, saponification value 205, iodine value 84 - 94 g / 100 g, density about 0.971 - 1.02 g / cm 3 ; 5. C12 - C14 alkyl glycidyl ether: Lanabai, CAS No. 68609 - 97 - 2; 6. Polyethylene glycol monoallyl ether: Lanabai, CAS No. 27274 - 31 - 3, content 99%; 7. Fumed silica: Cabot, fumed silica, particle size 10 - 30 μm; 8. Calcium carbonate: light calcium carbonate, particle size 800 - 1000 mesh; 9. Diatomite: calcined diatomite, particle size 800 - 1000 mesh; 10. Zinc oxide: particle size 20 - 50 nm. Examples
[0029] Example 1 Example 1 discloses a process for preparing insoles using recycled scraps, including the following steps: S1. Crush 20 kg of recycled scraps to a crushing particle size of 0.2 - 1 mm, then perform pickling with an acid pickling agent, pickle for 60 min at a temperature of 40°C, then wash with water and dry to obtain scrap particles; S2. Take 10 kg of scrap particles, add 0.2 kg of dodecyl glycidyl ether as a pretreatment agent and knead for 60 min at a temperature of 80°C to obtain pretreated scraps; S3. Add 3 kg of pretreated scraps, 0.6 kg of poly(methyl vinyl ether / maleic anhydride) copolymer, 6 kg of polyurethane elastomer, 0.4 kg of tetraricinoleate, 1 kg of filler (composed of fumed silica and calcium carbonate with a weight ratio of 2:1), 0.4 kg of azodicarbonamide as a blowing agent, 0.3 kg of zinc oxide as a foaming aid, and 0.1 kg of antioxidant (composed of antioxidant 1010 and antioxidant 168 with a weight ratio of 1:1) into a screw extruder for melt extrusion. Control the temperatures at each stage as follows: the temperature of zone 1 is 160 °C, the temperature of zone 2 is 165 °C, the temperature of zone 3 is 170 °C, the temperature of zone 4 is 170 °C, and the die temperature is 165 °C. Then cool and pelletize; place it in a compression molding foaming device for compression molding and foaming, control the compression molding temperature at 190 °C, the compression molding pressure at 8 MPa, and compress for 10 - 15 min to obtain insoles; The pickling agent is prepared from 2 wt% hydrochloric acid, 2 wt% glycolic acid, 1 wt% sodium dodecylbenzenesulfonate, and 5 wt% water.
[0030] Examples 2 - 3 The differences between Examples 2 - 3 and Example 1 lie in the raw material dosages and preparation parameters. See Table 1 below for details.
[0031] Table 1 Parameter Table of Examples 1 - 3 Example 4 The difference between Example 4 and Example 1 is that the pretreatment agent in step S2 is composed of C12 - C14 alkyl glycidyl ether and polyethylene glycol monoallyl ether with a weight ratio of 1:1, and the others are the same as in Example 1.
[0032] Example 5 The difference between Example 5 and Example 1 is that the pretreatment agent in step S2 is composed of C12 - C14 alkyl glycidyl ether and polyethylene glycol monoallyl ether with a weight ratio of 1:2, and the others are the same as in Example 1.
[0033] Comparative Examples Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that dodecyl glycidyl ether in step S2 is equally replaced by vinyltrimethoxysilane, and the others are the same as in Example 1.
[0034] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the poly(methyl vinyl ether / maleic anhydride) copolymer in step S3 is equally replaced by styrene - grafted maleic anhydride with a maleic anhydride content of 18%, and the others are the same as in Example 1.
[0035] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the polymethyl vinyl ether / maleic anhydride copolymer in Step S3 is replaced with an ethylene-vinyl acetate copolymer in equal amount, Yangzi Petrochemical, V5110J.
[0036] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the tetraricinoleate is replaced with dioctyl phthalate in equal amount, and the others are the same as in Example 1.
[0037] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the scrap particles are not pretreated in Step S2, and other raw materials in Step S3, as well as 0.2 kg of dodecyl glycidyl ether, are directly added to the prepared scrap particles, and the others are the same as in Example 1.
[0038] Performance detection test The insoles prepared in Examples 1-5 and Comparative Examples 1-5 were subjected to performance tests as follows: Insole parameters: size 38; thickness: 6 mm at the front, 12 mm at the arch, and 8.8 mm at the heel U-cup; 1. Resilience test: Using a compression testing machine, the insole was compressed by 50%, and after recovering for 30 s, the cyclic test was continued. The cyclic compression was carried out 25 times, and then the resilience rate (unit: %) at the heel position of the insole was detected with reference to the falling ball method resilience test standard of GB / T 6670, and the test results were tested and calculated.
[0039] 2. Bending test: The insole was subjected to a bending resistance test. Under the temperature condition of 25 °C, it was folded at 90° using a bending resistance tester, and the bending rate was controlled at 80 times / min. Observation was carried out every 10,000 tests, and the number of times the insole broke (unit: 10,000 times) was recorded, and the test results were tested and recorded.
[0040] 3. Sweat resistance test: The insole was immersed in neutral standard artificial sweat for 72 h. After drying, the insole was subjected to a bending resistance test. Under the temperature condition of 25 °C, it was folded at 90° using a bending resistance tester, and the bending rate was controlled at 80 times / min. Observation was carried out every 10,000 tests, and the number of times the insole broke (unit: 10,000 times) was recorded, and the test results were tested and recorded.
[0041] The following are the performance test data of the insoles prepared in Examples 1-5 and Comparative Examples 1-5, as specifically shown in Table 2 below.
[0042] Table 2 Performance data table of Examples 1-5 and Comparative Examples 1-5 Combined with Examples 1-3, Examples 4-5, and Comparative Example 1 and Table 2, it can be concluded that using a substance containing a long-chain ether group as a pretreatment agent to knead the scrap particles can improve the resilience, sweat resistance, and bending resistance of the prepared insole. In Examples 4-5, the substance containing a long-chain ether group was further optimized. It was found that using C12-C14 alkyl glycidyl ether and polyethylene glycol monoallyl ether in a preferred weight ratio as the pretreatment agent improved the performance of the prepared insole. This may be because using a substance containing a long-chain ether group in a preferred type and ratio as the pretreatment agent can improve the flexibility and compatibility of the pretreated scrap, thereby improving the performance of the prepared insole.
[0043] Combined with Example 1 and Comparative Examples 2-4 and Table 2, it can be concluded that compared with Comparative Examples 2-4, in Example 1, the performance of the prepared insole was significantly improved by compounding the pretreated scrap, polyurethane elastomer, poly(methyl vinyl ether / maleic anhydride) copolymer, and tetraricinoleate in a preferred dosage ratio. This may be because it can improve the compatibility and dispersion uniformity of the pretreated scrap in the polyurethane elastomer system, and also improve the uniformity and stability of subsequent melting and compression molding and foaming.
[0044] Combined with Example 1 and Comparative Example 5 and Table 2, it can be concluded that in this application, first using a pretreatment agent to pretreat the scrap particles to prepare pretreated scrap, and then compounding the pretreated scrap with other substances improved the performance of the prepared insole. This may be because the pretreatment process can improve the softness and compatibility of the scrap, so that in the subsequent melting process, an insole material with a more dense molecular structure can be formed.
[0045] This specific embodiment is only an explanation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.
Claims
1. A process for preparing insole by using recycled scraps, characterized in that, It includes the following steps: S1. Crush the recycled scraps, pickle them with acid, wash them with water and dry them to obtain scrap particles; S2. Add a pretreatment agent accounting for 2-4 wt% of the scrap particles and conduct heat kneading to obtain pretreated scraps; S3. Melt-extrude the pretreated scraps, poly(methyl vinyl ether / maleic anhydride) copolymer, polyurethane elastomer, tetraricinoleic acid ester, filler, foaming agent, foaming aid and antioxidant, granulate them, and conduct compression molding and foaming to obtain insoles; The pretreatment agent in step S2 is a substance containing a long-chain ether group.
2. The process for preparing insoles using recycled scraps according to claim 1, wherein: The pretreatment agent in step S2 is composed of C12-C14 alkyl glycidyl ether and polyethylene glycol monoallyl ether with a weight ratio of 1:(1-2).
3. A process for preparing insole by using recycled scraps according to claim 1, characterized in that: The particle size of the crushed recycled scraps in step S1 is 0.2-2 mm.
4. The process for preparing insole by using recycled scraps according to claim 1, characterized in that: The kneading temperature in step S2 is 80-100 °C.
5. A process for preparing insole by using recycled scraps according to claim 1, characterized in that: The weight parts usage amounts of the components in step S3 are as follows: Pretreated scraps 30-50 parts Polyurethane elastomer 60-80 parts Poly(methyl vinyl ether / maleic anhydride) copolymer 6-12 parts Filler 10-20 parts Tetraricinoleic acid ester 4-8 parts Foaming agent 4-6 parts Foaming aid 3-5 parts Antioxidant 1-3 parts.
6. A process for preparing insole by using recycled scraps according to claim 1, characterized in that: The filler is any one or a combination of silica, calcium carbonate, and diatomaceous earth.
7. A process for preparing insole by using recycled scraps according to claim 1, characterized in that: The foaming agent is azodicarbonamide, and the foaming aid is zinc oxide.
8. A process for preparing insole by using recycled scraps according to claim 1, characterized in that: The antioxidant is a hindered phenol antioxidant and / or a phosphite antioxidant.
9. A process for preparing insole by using recycled scraps according to claim 1, characterized in that: The melting temperature in step S3 is 160-170 °C.
10. A process for preparing insole by using recycled scraps according to claim 1, characterized in that: The compression molding temperature in step S3 is 180-190 °C, and the compression molding time is 10-15 min.