Radiation-free and polishing-free foamed sole material and application thereof

Abstract

The application belongs to the technical field of foamed materials, and particularly relates to a foamed sole material free of irradiation and polishing and application thereof; the foamed sole material has a density of 0.1-0.4 g / cm 3 , and a chlorine content of 2.0-42%; the foamed sole material is directly bonded with a sole or an upper without treatment agent treatment, irradiation and polishing processes, and has a bonding strength of >30 N / mm and a compression deformation of <30%. The raw material composition of the foamed sole material comprises: chloride rubber, 6-100 parts; ethylene-based elastomer, 0-94 parts; inorganic filler, 0-30 parts; crosslinking agent, 0.1-1.5 parts; lubricant, 0.2-2.5 parts; active agent, 0.5-3.5 parts; and foaming agent, 0.8-4.0 parts. The foamed sole material prepared by the application has high resilience, comfort and compression deformation resistance, is free of UV irradiation and polishing, and has a high finished product rate.

Description

Technical Field

[0001] This invention belongs to the field of foam material technology, and in particular relates to a foam shoe sole material that requires no irradiation or grinding and its application. Background Technology

[0002] As a typical labor-intensive traditional industry, the footwear manufacturing industry has a complex and intricate production process, encompassing multiple steps such as molding, bonding, finishing, and packaging. The entire production process requires a large amount of manual labor, making the industry highly dependent on workforce resources. In recent years, with the continuous rise in social labor costs and the widening labor shortage in the industry, the production and operating costs of footwear companies have continued to climb, increasing overall cost pressure on the industry. At the same time, with the continuous upgrading of consumer quality, consumers are increasingly demanding higher standards for the wearing experience and overall performance of footwear products. Especially in the athletic shoe sector, high resilience and ultimate comfort have become core indicators for consumers when choosing products.

[0003] To meet market demands, the industry commonly incorporates low-polarity polymers such as POE and EPDM into the foaming formula of shoe sole materials to optimize the flexibility and resilience of the sole. However, these polymers have extremely low surface activity, which significantly reduces the adhesion of the sole substrate, making it prone to quality problems such as delamination and peeling. Currently, the industry's common improvement method involves applying a special treatment agent for modification, followed by multiple post-treatment processes such as UV irradiation and mechanical polishing to improve the adhesion between the sole material and the outsole or upper. However, this series of processes continuously releases volatile organic compounds (VOCs) and large amounts of dust pollutants during production, which not only violates the trend of green and environmentally friendly industrial development but also seriously damages the respiratory system and health of frontline workers.

[0004] Patent document CN202110783783 discloses a non-grinding athletic shoe sole and its preparation method. By adding polymers such as ethylene ester-carbon monoxide copolymer, ethylene-acrylic acid copolymer, and ethylene-methacrylic acid ionized resin to the midsole foaming material for blending and foaming, the polarity of the foamed midsole is greatly improved, saving the midsole roughening process. Similarly, the addition of polyacrylate rubber (ACM rubber) to the rubber outsole also improves the outsole's polarity, saving the outsole roughening process. This technical solution improves adhesion by increasing the polarity of the formulation materials, achieving the goal of eliminating the need for sanding. However, the formulation uses ethylene-acrylic acid copolymer, ethylene-methacrylic acid ionized resin, and polyacrylate rubber, which are relatively expensive. While this reduces the cost of the sanding process, it further increases the overall formulation cost.

[0005] Patent document CN202110690855 discloses an EVA foam material, its preparation method, and its applications. The foamed shoe sole is prepared by combining liquid epoxidized polybutadiene resin with EVA in a formulation. The epoxy groups in the liquid epoxidized polybutadiene resin react with the substrate to form chemical bonds that are stronger than typical physical interactions, providing excellent adhesion. However, the large number of double bonds remaining in the liquid epoxidized polybutadiene resin leads to poor weather resistance in the foamed shoe sole, causing it to yellow after a period of wear, thus limiting its practical application.

[0006] Patent documents CN202411661221, CN202311343061, and CN202511272508 add polar materials or use additives to improve interaction forces in the formula, focusing on optimizing the shortcomings of the sole in terms of adhesion, but do not achieve the technical effect of direct bonding without irradiation or sanding.

[0007] Therefore, developing environmentally friendly foamed shoe sole materials that combine high resilience, comfort, and resistance to compression deformation, while being UV-free and requiring no polishing, has become the direction of research. Summary of the Invention

[0008] The purpose of this invention is to address the problem that existing foamed shoe sole materials cannot be directly bonded to the outsole or upper, requiring a treatment agent, irradiation, and polishing to improve bonding strength. This invention provides an irradiation-free and polishing-free foamed shoe sole material and its application. This material improves the adhesion of foamed shoe sole materials, allowing direct bonding to the outsole or upper without treatment agents, irradiation, or polishing. It meets bonding strength requirements while also providing comfort, high resilience, and resistance to compression deformation. Furthermore, it saves labor steps and reduces VOC release and dust issues during shoe material production. In addition, the method has cost and environmental advantages, and a high yield rate, mitigating the low yield rate caused by uneven irradiation.

[0009] To achieve the above objectives, the present invention provides the following technical solution: In the first aspect, a foamed shoe sole material that requires no irradiation or polishing is provided, wherein the density of the foamed shoe sole material is 0.1~0.4 g / cm³. 3 (For example, 0.12 g / cm) 3 0.15g / cm 3 0.20g / cm 3 0.25g / cm 3 0.30g / cm 3 0.35g / cm 3 0.38g / cm 3Chlorine content ranges from 2.0% to 42% (e.g., 2.5%, 3%, 4%, 5%, 8%, 10%, 15%, 20%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, etc.). The foamed sole material is directly bonded to the outsole or upper without treatment agents, irradiation, or polishing. Its bonding strength is >30N / mm (e.g., 32N / mm, 35N / mm, 40N / mm, 43N / mm, 45N / mm, 48N / mm, 50N / mm, 55N / mm, etc.), and its compression deformation is <30% (e.g., 29%, 28%, 26%, 25%, 24%, 20%, 18%, etc.).

[0010] According to the foamed shoe sole material provided by the present invention, in some embodiments, the raw material composition of the foamed shoe sole material comprises the following components in parts by weight: The main ingredients include: Chlorinated rubber, 6 to 100 parts (e.g., 8 parts, 12 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 65 parts, 80 parts, 85 parts), preferably 10 to 60 parts; Vinyl elastomer, 0 to 94 parts (e.g., 2 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 65 parts, 80 parts, 85 parts), preferably 1 to 90 parts; Inorganic filler, 0 to 30 parts (e.g., 0.5 parts, 1 part, 2 parts, 4 parts, 5 parts, 8 parts, 10 parts, 15 parts, 18 parts, 22 parts, 25 parts, 28 parts), preferably 0 to 20 parts; In the main ingredient, the total number of parts of each component is 100 parts by weight; The auxiliary materials include: Crosslinking agent, 0.1 to 1.5 parts (e.g., 0.15 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1.0 parts, 1.2 parts, 1.4 parts), preferably 0.2 to 1.0 parts; Lubricant, 0.2 to 2.5 parts (e.g., 0.25 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.5 parts, 2 parts, 2.4 parts), preferably 0.4 to 1.6 parts; Surfactant, 0.5 to 3.5 parts (e.g., 0.55 parts, 0.6 parts, 0.8 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.4 parts), preferably 0.7 to 2.5 parts; Foaming agent, 0.8 to 4.0 parts (e.g., 0.85 parts, 0.9 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 3.8 parts); The weight parts of each component in the excipients are based on 100 parts by weight of the main ingredient (i.e., each component in the excipients is a component added in addition to 100 parts by weight of the main ingredient).

[0011] In some embodiments, the chlorinated rubber is selected from at least one of chlorinated polyethylene rubber, chloroprene rubber, chlorosulfonated polyethylene, and ethylene-vinyl chloride-acrylate copolymer rubber; preferably, it is chlorinated polyethylene rubber.

[0012] In some embodiments, the chlorinated polyethylene rubber contains 20% to 44% chlorine (e.g., 25%, 30%, 35%, 36%, 38%, 40%).

[0013] In some embodiments, the chlorine content in the chloroprene rubber is 25% to 35% (e.g., 26%, 27%, 28%, 30%, 32%, 34%).

[0014] In some embodiments, the chlorine content in the chlorosulfonated polyethylene is 25% to 45% (e.g., 26%, 28%, 30%, 32%, 35%, 38%, 40%, 44%).

[0015] In some embodiments, the chlorine content in the ethylene-vinyl chloride-acrylate copolymer rubber is 20% to 44% (e.g., 22%, 25%, 26%, 28%, 30%, 32%, 35%, 38%, 40%, 42%).

[0016] In some embodiments, the vinyl elastomer is selected from at least one of ethylene-vinyl acetate copolymer, ethylene-octene copolymer, ethylene-butene copolymer, ethylene-propylene-conjugated diene copolymer, hydrogenated butadiene-styrene block copolymer, and oil-extended butadiene-styrene block copolymer.

[0017] In some embodiments, the inorganic filler is selected from at least one of calcium carbonate, sodium sulfate, talc, silica, barium sulfate, and calcium sulfate; and its mesh size is 800 to 5000 mesh (e.g., 1000 mesh, 1200 mesh, 1500 mesh, 2000 mesh, 3000 mesh, 4000 mesh, 4500 mesh).

[0018] In some embodiments, the crosslinking agent is selected from at least one of dicumyl peroxide (DCP), α,α-bis(tert-butylperoxide)dicumyl peroxide (BIBP), 2,5-dimethyl-2,5-bis(tert-butylperoxide)hexane, and 4,4-(bis-tert-butylperoxide)valerate n-butyl ester; preferably selected from at least one of dicumyl peroxide and α,α-bis(tert-butylperoxide)dicumyl peroxide.

[0019] In some embodiments, the lubricant is selected from at least one of stearic acid, oleic acid, polyethylene wax, calcium stearate, zinc stearate, oxidized polyethylene wax, paraffin wax, and white oil; preferably selected from at least one of stearic acid, zinc stearate, and calcium stearate.

[0020] In some embodiments, the activator is selected from at least one of zinc oxide, magnesium oxide, and triallyl isocyanurate (TAIC); preferably zinc oxide.

[0021] In some embodiments, the foaming agent is selected from at least one of azodicarbonamide (AC), sodium bicarbonate (NC), and N,N'-dinitrospentamethylenetetramine (H foaming agent); preferably azodicarbonamide.

[0022] In a second aspect, an application of the foamed sole material as described above is provided, wherein the foamed sole material is directly bonded to the outsole or upper without treatment with a processing agent, irradiation, or polishing.

[0023] The method for preparing the foamed shoe sole material described herein includes the following steps: (1) Internal mixing process: Weigh each material component of the foam shoe floor material composition according to the proportion, and pour the measured material into the internal mixer for internal mixing. The internal mixing time is 10-20 minutes. After the internal mixing reaches 110-120℃ (e.g., 112℃), the material is discharged and then granulated in a single screw granulator after open mixing. The granulation temperature is 80-90℃ (e.g., 85℃). After granulation, foam material granules are obtained and left to stand for later use. (2) Molding process: Weigh the foamed material granules obtained above, pour them into the mold, heat and pressurize them to crosslink and foam. Set the temperature to 160-200℃ (e.g., 180℃) and the time to 400-500 seconds (e.g., 450 seconds). After the crosslinking and foaming are completed, take out the foamed material shoe blank, cool it and trim the rough edges. Then put the shoe blank into the mold to heat and press it to shape it. Set the temperature to 160-200℃ (180℃) and the time to 400-500 seconds (450 seconds). Take out the mold and cool it. Take out the shoe sole to obtain the foamed shoe sole material.

[0024] Alternatively, the method for preparing the foamed shoe sole material includes the following steps: (1) Internal mixing process: Weigh each material component of the foam shoe floor material composition according to the proportion, and pour the measured material into the internal mixer for internal mixing. The internal mixing time is 10-20 minutes. After the internal mixing reaches 110-120℃ (e.g., 112℃), the material is discharged and then granulated in a single screw granulator after open mixing. The granulation temperature is 80-90℃ (e.g., 85℃). After granulation, foam material granules are obtained and left to stand for later use. (2) Injection molding process: Before each injection of material into the mold, the mold needs to be cleaned and a release agent is sprayed on the mold surface; the release agent can be a mixture of silicone oil (polydimethylsiloxane) and water; the foamed material particles obtained above are injected into the mold through an injection machine; the barrel temperature is set to 85-100℃ (e.g., 90℃), the mold vulcanization temperature is 160-180℃ (e.g., 175℃), the vulcanization time is adjusted and set, and after vulcanization is completed, the foamed shoe is taken out and cooled and shaped to obtain the foamed shoe sole material.

[0025] The application of the foamed shoe sole material described in this article includes the following steps: After the prepared foamed sole material is left at room temperature for 24 hours, it is bonded using a bonding process that requires no irradiation and no sanding. Without any coating agent treatment, UV irradiation, or polishing, the foamed sole material and upper fabric are directly brushed with water-based PU adhesive. The glued soles are then dried in an oven at 60-70℃. After drying in the oven, they are promptly bonded and pressed to obtain samples that are free from irradiation and polishing.

[0026] In existing technologies, the bonding process for foamed shoe sole materials to the outsole or upper involves irradiation and sanding. The procedure is as follows: a treatment agent (containing: vinyl acetate resin, methyl methacrylate, acrylic acid, photoinitiator, etc.; solvents can be ethyl acetate, toluene, acetone, or methyl ethyl ketone; solid content: 0.8~1.5%) is evenly applied to the inner side of the foamed shoe sole where bonding is required, and then allowed to air dry at room temperature. After treatment with the treatment agent, the foamed shoe sole must undergo UV irradiation within 2 hours, with an irradiation energy intensity of 0.45~0.55 W / cm². 2 After UV irradiation, the foamed soles are sanded with a wool roller or grinding wheel on the parts that need to be bonded. Water-based PU glue is brushed onto the treated foamed soles and the upper fabric. The glued soles are then dried in an oven production line at a temperature of 60-70℃. After drying in the production line oven, they are promptly bonded and pressed to obtain the irradiated and sanded samples.

[0027] Compared with existing technologies, the main advantages of the technical solution of this invention are: In the formulation of the raw material composition for the foamed shoe sole material of this invention, chlorinated rubber is selected as the main material. The flowability of the foamed material can be adjusted by combining it with a portion of vinyl elastomers. Chlorinated rubber is a highly polar material, which not only has good compatibility with polar adhesive layers, forming a strong intermolecular bond, but also has a high surface free energy, achieving molecular-level contact with the adhesive layer and improving the material's adhesion. The foamed shoe sole material itself has good adhesive properties, which can optimize the production process, reduce labor and equipment input, avoid the use of treatment agents and UV irradiation, reduce VOC release, eliminate the need for sanding, and avoid workshop dust, thereby optimizing the workshop production environment (by eliminating the irradiation and sanding steps, the production cost can be reduced by 1 yuan per pair of shoes).

[0028] Chlorinated rubber possesses excellent rubbery feel and melt strength, enabling the formation of a uniform and dense cell structure and high internal air pressure. This improves the comfort and resilience of foamed shoe sole materials. While achieving superior performance, it also reduces the use of weakly polar materials such as POE and EPDM, further enhancing its adhesive properties. Chlorinated rubber exhibits strong hydrogen bonding, resulting in strong intermolecular forces and a compact molecular structure. This significantly improves the airtightness of the cells, suppressing gas leakage and providing excellent resistance to compression set.

[0029] In the formulation of the raw material composition for the foamed shoe sole material, the use of chlorinated rubber can improve melt strength and inhibit the precipitation of small molecules, resulting in a good anti-sticking effect. Therefore, the concentration of release agent sprayed on the mold surface when producing foamed materials using a one-time injection molding process can be reduced. This can improve the sticking problem, increase the yield of production, and reduce costs (every 1% improvement in yield will increase the company's net profit by 1%, which has a huge impact on the company's profits). It can also avoid the adverse effects of excessive release agent on subsequent bonding, further improving the bonding strength. Detailed Implementation

[0030] To provide a detailed understanding of the technical features and content of this invention, preferred embodiments will be described in more detail below. While preferred embodiments are described in the examples, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply.

[0031] In the following examples and comparative examples, unless otherwise specified, the reagents or raw materials are all commercially available conventional products; among them, EVA: Jiangsu Sirbang Petrochemical Co., Ltd., UE3315; EVA: Ningxia Baofeng Energy Group Co., Ltd., EVA2806F; Ethylene-vinyl acetate copolymer (EVA): Taiwan Plastics Industrial Co., Ltd. (7350M); POE: LG Chem Ltd., LC170; POE: LG Chem Ltd., LC168; EPDM: Shanghai Sinopec Mitsui Elastomers Co., Ltd., 3092PM; SEBS: Sinopec Hunan Petrochemical Co., Ltd., YH688; Chlorinated polyethylene (CPE): Shandong Rike Rubber & Plastics Technology Co., Ltd. 3550, chlorine content approximately 35%; Chlorinated polyethylene (CPE): Shandong Rike Rubber & Plastics Technology Co., Ltd. 135A, chlorine content approximately 35%; Ethylene-vinyl chloride-acrylate copolymer rubber (PORE): Shandong Meideye Rubber Co., Ltd., PORE9168, chlorine content approximately 21%; Chloroprene rubber: Denka Co., Ltd., DCR36, chlorine content approximately 27%; Calcium carbonate: Qingzhou Yuxin Calcium Industry Co., Ltd., 1250 mesh light calcium carbonate; Talc: Quanzhou Xufeng Powder Raw Materials Co., Ltd., BHS805; Zinc oxide: Weifang Aolong Zinc Industry Co., Ltd., 99.7% purity; Stearic acid: Shijiazhuang Lumen Chemical Co., Ltd., 1801; Zinc stearate: Anhui Ruihua New Materials Co., Ltd.; DCP: Akzo Nobel NV, DCP3106; BIBP: Akzo Nobel NV, KNOX 140F; AC foaming agent: Fujian Jinlang New Material Technology Co., Ltd., AC6000.

[0032] <Testing Methods> (1) Hardness, Shore C: According to the national standard GB / T 531.1-2008 "Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness tester method (Shore hardness)", the Shore C hardness tester method.

[0033] (2) Chlorine content: According to the national standard GB / T 7139-2023 "Determination of chlorine content in polyvinyl chloride homopolymers and copolymers", the combustion bottle method was used.

[0034] (3) Adhesion strength: Tested according to GB / T21396-2022 "Test Methods for Adhesion Strength of Upper and Sole in Footwear", with a peeling speed of 100 mm / min and the result accurate to 0.1 N / mm.

[0035] The assessment of the failure pattern of the adhesive layer is carried out in accordance with Clause 7.2 of this national standard, and is divided into: A. Adhesive failure, C. Filamentation failure, N. Cohesive failure, S. Material delamination, and M. Material failure.

[0036] (4) Density: The density was tested according to GB / T 6343 2009 "Determination of apparent density of foamed plastics and rubber". Five samples were tested for each example and comparative example, and the average value was taken.

[0037] (5) Resilience rate: According to industry standard HG / T4993-2016 "Test method for resilience of microporous materials for footwear", the unit is %.

[0038] (6) Compression deformation: HGT2876-2009 "Test method for compression deformation of microporous materials for rubber and plastic shoes", compression time of 6h at 50℃, unit is %, accurate to one decimal place.

[0039] In the following preparation examples, embodiments, and comparative examples, the amounts of raw materials used are all expressed in parts by weight.

[0040] Example 1: The raw material composition for foamed shoe sole material, by weight, includes: 70 parts of ethylene-vinyl acetate copolymer (EVA2806F), 25 parts of chlorinated polyethylene rubber (CPE 3550), and 5 parts of talc, which constitute the main material, with a total usage of 100 parts; 1.2 parts of zinc oxide, 0.45 parts of stearic acid, 0.6 parts of zinc stearate, 0.32 parts of BIBP, and 3.10 parts of AC foaming agent.

[0041] The preparation of foamed shoe sole materials includes the following steps: (1) Internal mixing process: Weigh the materials according to the above components and proportions, and pour the weighed materials into the internal mixer for internal mixing. The internal mixing time is 10 minutes. After the internal mixing reaches 112°C, the materials are discharged and then granulated in a single screw granulator after open mixing. The granulation temperature is 85°C. Granulation is completed to obtain foamed material granules, which are then left to stand for later use. (2) Molding process: Weigh the foamed material granules obtained above, pour them into the mold, heat and pressurize them to crosslink and foam. Set the temperature to 180℃ and the time to 450 seconds. After the crosslinking and foaming are completed, take out the foamed material shoe blank, cool it and trim the rough edges. Then put the shoe blank into the mold, heat and press it to shape it. Set the temperature to 180℃ and the time to 450 seconds. Then take out the mold and cool it. Take out the sole material to obtain the foamed sole material.

[0042] After the prepared foamed shoe sole material is left at room temperature for 24 hours, it is then bonded together.

[0043] For bonding foamed shoe sole materials, either an irradiation and sanding bonding process or a non-irradiation and non-sanding bonding process can be used. The irradiation, polishing, and bonding processes are as follows: Apply the treatment agent evenly to the inner side of the foamed sole material where bonding is required (the treatment agent contains: vinyl acetate resin, methyl methacrylate, acrylic acid, photoinitiator, etc.; solvents can be ethyl acetate, toluene, acetone, methyl ethyl ketone; solid content: 0.8~1.5%) and allow it to dry at room temperature. After treatment, the foamed sole material must be subjected to UV irradiation within 2 hours, with an irradiation energy intensity of 0.45~0.55W / cm². 2 The foamed soles, after being irradiated with UV light, are then sanded at the areas to be bonded using a wool roller or grinding wheel. Water-based PU adhesive is then applied to both the sanded foamed soles and the upper fabric. The glued soles are then dried in an oven at 60-70℃. After drying, they are promptly bonded together and pressed to obtain the irradiated and sanded test samples.

[0044] The bonding process that requires no irradiation and no sanding is as follows: Without any treatment agent, UV irradiation, or polishing, the foamed sole material and upper fabric are directly coated with water-based PU adhesive. After the adhesive is applied, the sole is dried in an oven at 70°C. After drying in the oven, the sole is immediately bonded and pressed to obtain a test sample that is free from irradiation and polishing.

[0045] The foamed shoe sole material prepared in Example 1 was bonded using a non-irradiation, non-grinding bonding process to prepare test sample 1.

[0046] Comparative Example 1: The foamed shoe sole material prepared in Example 1 was bonded using an irradiation and grinding bonding process to prepare test sample 2.

[0047] Test samples 1 and 2 were tested separately, and the test results are shown in Table 1.

[0048] Table 1 Performance test results of the obtained test samples

[0049] The peeling interface state is divided into: material damage and adhesion damage.

[0050] Material failure refers to: under tensile force, when the adhesive interface is strong, the stress exceeds the limit of delamination tearing of the sole, and the breakage occurs at the sole, resulting in a tear in the sole; Adhesion failure refers to the separation of the adhesive surface under tensile force, with cracking occurring at the adhesive joint between the sole and the upper.

[0051] Test sample 1 and test sample 2 used the same foamed sole material, but adopted two different bonding processes. The test data shows that after testing, test sample 1 did not show peeling at the bonding surface. Compared with test sample 2, which was irradiated and polished, the test data of the two were basically the same, indicating that test sample 1 made of the foamed sole material obtained in Example 1 still has a good bonding effect without irradiation and polishing, and the irradiation and polishing process can be omitted.

[0052] Examples 2-5, Comparative Examples 2-4 (Changes in the amount of chlorinated rubber): The components and their amounts in the raw material composition for foamed shoe sole materials, by weight, are shown in Table 2.

[0053] The preparation of the foamed shoe sole material follows the preparation method and process described in Example 1.

[0054] Table 2 Material composition and formulation of Examples 2-5 and Comparative Examples 2-4 (unit: parts by weight)

[0055] The corresponding foamed shoe sole material was prepared and bonded after being left at room temperature for 24 hours.

[0056] The irradiation, polishing and bonding process, as well as the irradiation-free and polishing-free bonding process, were carried out according to the methods described above to obtain the corresponding test samples.

[0057] The bonding process used for the foamed shoe sole material, the corresponding test samples obtained, and the parameters of the foamed shoe sole are shown in Table 3.

[0058] Table 3. Bonding processes and performance test results for foamed shoe sole materials.

[0059] The test samples obtained above were tested to evaluate their adhesive strength. Specific data are shown in Table 4.

[0060] Table 4 Performance Test Results

[0061] As can be seen from the data in Table 4, test samples 3-6 used the foamed shoe sole material prepared in Examples 2-5, and used a radiation-free and sanding-free bonding process. The material has high bonding strength and good bonding effect. When the bonding effect is good, the material bonding interface shows a material failure state when subjected to peel force test, and it does not peel off at the bonding interface.

[0062] The test data from Comparative Examples 3 and 4 show that Test Sample 9 uses the foaming material obtained from Comparative Example 4 (without added chlorinated rubber), but adopts an irradiation and grinding bonding process, which has a good bonding effect. When the bonding interface is in a state of material failure, the bonding strength is greatly improved.

[0063] Test data from Comparative Examples 2 and 3 and Examples 2-5 revealed that, under the same bonding process, the bonding strength of the material increased with the increase of the amount of chlorinated polyethylene rubber added and the chlorine content in the foaming material composition. Although 5 parts of chlorinated rubber were added to the raw material composition of Comparative Example 2, when the chlorine content was below a certain level, although the performance was slightly better than the test sample prepared without chlorinated polyethylene rubber (Comparative Example 3), the bonding effect of the sole was still poor, and it still required irradiation and polishing treatment.

[0064] Examples 6-8, Comparative Example 5 (Selection of Chlorinated Rubber Type): The components and their amounts in the raw material composition for foamed shoe sole materials, by weight, are shown in Table 5.

[0065] The preparation of the foamed shoe sole material follows the preparation process and method described in Example 1.

[0066] Table 5. Material composition and formulation of Examples 6-8 and Comparative Example 5 (unit: parts by weight)

[0067] The corresponding foamed shoe sole material was prepared and bonded after being left at room temperature for 24 hours.

[0068] The foamed sole material adopts a bonding process that is free from irradiation and sanding: it is not treated with a treatment agent or subjected to UV irradiation, nor is it sanded; the foamed sole material and the outsole are directly brushed with water-based PU adhesive; the sole after applying the adhesive is put into an oven production line for drying at an oven temperature of 70℃. After drying in the production line oven, it is promptly bonded and pressed to obtain corresponding test samples that are free from irradiation and sanding, resulting in test samples 10 to 13.

[0069] The bonding process used for the foamed shoe sole material, the corresponding test samples obtained, and the parameters of the foamed shoe sole are shown in Table 6.

[0070] Table 6. Bonding processes and performance test results for foamed shoe sole materials.

[0071] The test samples obtained above were tested to evaluate their adhesive strength. Specific data are shown in Table 7.

[0072] Table 7 Performance Test Results

[0073] As can be seen from the data in Table 7, adding other rubbers containing chlorine to the composition formulation also results in high adhesive strength and improved bonding effect, achieving a process that eliminates the need for irradiation and sanding. Adding chlorinated rubber to the formulation significantly improves the compression set performance of foamed shoe soles. This is because the addition of chlorine forms hydrogen bonds, increasing the material's airtightness, thereby alleviating deformation problems during shoe wear and extending the shoe's lifespan.

[0074] Examples 9-10, Comparative Examples 6-8: The components and their amounts in the raw material composition for foamed shoe sole materials, by weight, are shown in Table 8.

[0075] Table 8. Material composition and formulation of Examples 9-10 and Comparative Examples 6-8 (unit: parts by weight)

[0076] The preparation of foamed shoe sole materials includes the following steps: (1) Internal mixing process: Weigh the materials according to the components and their proportions in Table 8, and put the weighed materials into the internal mixer for internal mixing. The temperature is raised by the shear heat during the internal mixing process, and the temperature is controlled by circulating water. The internal mixing time is maintained for 9 minutes. When the material temperature rises to 106℃, the internal mixing is stopped, the material is discharged, and it is processed by the open mill and enters the single screw granulation equipment. The barrel temperature is set to 80℃, and the material is extruded and granulated to complete the granulation and obtain foamed material granules, which are then left to stand for later use.

[0077] (2) Injection molding process: The foamed material particles prepared above are injected through an injection machine. The barrel temperature is set to 90℃ and the mold vulcanization temperature is 175℃. The vulcanization time is adjusted and set. After vulcanization is completed, the foamed shoe is taken out and cooled and shaped to obtain the foamed shoe sole material.

[0078] After the prepared foamed shoe sole material is left at room temperature for 24 hours, it is then bonded together.

[0079] The bonding process used for the foamed shoe sole material, the corresponding test samples obtained, and the parameters of the foamed shoe sole are shown in Table 9.

[0080] Table 9. Bonding processes and performance test results for foamed shoe sole materials.

[0081] The test samples obtained above were tested to evaluate their adhesive strength. Specific data are shown in Table 10.

[0082] Table 10 Performance Test Results

[0083] As can be seen from the data in Table 10, for Comparative Example 6 and Comparative Example 7, under the same bonding process conditions, after adding POE to the formulation, Comparative Example 7 tore at the bonding interface during the bonding performance test, showing an adhesive failure state. Compared with Comparative Example 6, the resilience of its foamed sole was improved, but the adhesion decreased, indicating that the addition of weakly polar POE material further reduced the bonding performance.

[0084] Comparative Example 8 and Comparative Example 7 have the same composition formulation (neither of which contains chlorinated rubber), but the foamed sole materials use different bonding processes; the test results show that after irradiation and grinding processes, the bonding interface is in a state of material damage.

[0085] By comparing the adhesive strength data of Examples 9 and 10, it was found that even with the presence of POE in the formulation of Example 10, the resulting foamed sole maintained excellent adhesion, with the adhesive interface showing material failure. Furthermore, compared to the addition of POE, the foamed sole with added chlorinated rubber exhibited better rebound.

[0086] Example 11, Comparative Examples 9-10: The components and their amounts in the raw material composition for foamed shoe sole materials, by weight, are shown in Table 11.

[0087] Table 11 Material composition and formulation of Example 11 and Comparative Examples 9-10 (unit: parts by weight)

[0088] The preparation of foamed shoe sole materials includes the following steps: (1) Internal mixing process: Weigh the materials according to the components and their proportions in Table 11, and put the weighed materials into the internal mixer for internal mixing. The temperature is raised by the shear heat during the internal mixing process, and the temperature is controlled by circulating water. The internal mixing time is maintained for 10 minutes. When the material temperature rises to 105℃, the internal mixing is stopped, the material is discharged, and it is processed by the open mill and enters the single screw granulation equipment. The barrel temperature is set to 78℃, and the material is extruded and granulated to complete the granulation and obtain foamed material granules, which are then left to stand for later use.

[0089] (2) Injection molding process: Before each injection of material into the mold, the mold needs to be cleaned and a release agent is sprayed on the mold surface; the foamed material granules prepared above are injected through the injection machine, the barrel temperature is set to 85℃, the mold vulcanization temperature is 175℃, the vulcanization time is adjusted and set, and after vulcanization is completed, the foamed shoe is taken out and cooled and shaped to obtain the foamed shoe sole material.

[0090] After the prepared foamed shoe sole material is left at room temperature for 24 hours, it is then bonded together.

[0091] The bonding process used for the foamed shoe sole material, the corresponding test samples obtained, and the parameters of the foamed shoe sole are shown in Table 12.

[0092] Table 12 Bonding Processes and Performance Test Results for Foamed Shoe Sole Materials

[0093] Yield: Production site data obtained based on one continuous shift (8 hours) of production.

[0094] Mold release agent: It is made by mixing silicone oil (polydimethylsiloxane) with water. The concentration of the mold release agent refers to the proportion of silicone oil in the mold release agent; the higher the proportion, the higher the concentration.

[0095] In a single injection molding process, the mold needs to be cleaned and a release agent sprayed on the mold surface before each injection of material into the mold. This prevents material and small molecules from contacting and adhering to the mold surface, thereby reducing product defects and improving yield.

[0096] The test samples obtained above were tested to evaluate their adhesive strength. Specific data are shown in Table 13.

[0097] Table 13 Performance Test Results

[0098] Combining the data in Tables 12 and 13, it can be seen that neither of the foaming material compositions in Comparative Examples 9 and 10 contained chlorinated rubber. Increasing the concentration of the release agent in the single injection molding process could improve the yield rate in the sole material production process to some extent and alleviate the problem of mold sticking, but a relatively large scrap rate still existed. Every 1% increase in the scrap rate would reduce the company's profit margin by nearly 1%; therefore, the yield rate is crucial for manufacturing companies. However, increasing the concentration of the release agent leads to poor adhesion; test sample 20 had the lowest adhesion strength.

[0099] Example 11 shows that by adding chlorinated rubber to the formulation, even in a small proportion, the scrap rate caused by sticking to the mold can be significantly improved. This not only increases the yield and the company's profit margin, but also improves the adhesion.

[0100] As can be seen from Example 11 and Comparative Example 2, a change of only 1 part by weight in the amount of chlorinated polyethylene can lead to a significant improvement in the adhesive strength of the material. This is because the change in the amount of chlorinated rubber added from 5 parts by weight to 6 parts by weight improves the adhesion, so that the failure state of the adhesive interface changes from adhesion failure to material failure when testing the adhesive strength, thereby greatly improving the adhesive strength.

[0101] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A foamed shoe sole material that requires no irradiation or polishing, characterized in that, The density of the foamed shoe sole material is 0.1~0.4 g / cm³. 3 The chlorine content is 2.0-42%; The foamed sole material is directly bonded to the outsole or upper without treatment agents, irradiation, or polishing. Its bonding strength is >30N / mm and its compression deformation is <30%.

2. The foamed shoe sole material according to claim 1, characterized in that, The raw material composition of this foamed shoe sole material comprises the following components in parts by weight: The main ingredients include: Chlorinated rubber, 6-100 parts, preferably 10-60 parts; Vinyl elastomer, 0-94 parts, preferably 1-90 parts; Inorganic filler, 0-30 parts, preferably 0-20 parts; In the main ingredient, the total number of parts of each component is 100 parts by weight; The auxiliary materials include: Crosslinking agent, 0.1 to 1.5 parts, preferably 0.2 to 1.0 parts; Lubricant, 0.2 to 2.5 parts, preferably 0.4 to 1.6 parts; Surfactant, 0.5-3.5 parts, preferably 0.7-2.5 parts; Foaming agent, 0.8~4.0 parts; The weight parts of each component in the auxiliary materials are based on 100 parts by weight of the main material.

3. The foamed shoe sole material according to claim 1, characterized in that, The chlorinated rubber is selected from at least one of chlorinated polyethylene rubber, chloroprene rubber, chlorosulfonated polyethylene and ethylene-vinyl chloride-acrylate copolymer rubber; preferably chlorinated polyethylene rubber.

4. The foamed shoe sole material according to claim 3, characterized in that, The chlorinated polyethylene rubber contains 20% to 44% chlorine. The chloroprene rubber contains 25% to 35% chlorine. The chlorosulfonated polyethylene contains 25% to 45% chlorine. The chlorine content in the ethylene-vinyl chloride-acrylate copolymer rubber is 20%~44%.

5. The foamed shoe sole material according to claim 1, characterized in that, The vinyl elastomer is selected from at least one of ethylene-vinyl acetate copolymer, ethylene-octene copolymer, ethylene-butene copolymer, ethylene-propylene-conjugated diene copolymer, hydrogenated butadiene-styrene block copolymer, and oil-extended butadiene-styrene block copolymer.

6. The foamed shoe sole material according to claim 1, characterized in that, The inorganic filler is selected from at least one of calcium carbonate, sodium sulfate, talc, silica, barium sulfate, and calcium sulfate; its mesh size is 800-5000 mesh.

7. The foamed shoe sole material according to any one of claims 1-6, characterized in that, The crosslinking agent is selected from at least one of dicumyl peroxide, α,α-bis(tert-butylperoxide)dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxide)hexane and 4,4-(bis-tert-butylperoxide)valerate n-butyl ester; preferably selected from at least one of dicumyl peroxide and α,α-bis(tert-butylperoxide)dicumyl peroxide.

8. The foamed shoe sole material according to any one of claims 1-6, characterized in that, The lubricant is selected from at least one of stearic acid, oleic acid, polyethylene wax, calcium stearate, zinc stearate, oxidized polyethylene wax, paraffin wax, and white oil; preferably selected from at least one of stearic acid, zinc stearate, and calcium stearate. The activator is selected from at least one of zinc oxide, magnesium oxide, and triallyl isocyanurate; preferably zinc oxide. The foaming agent is selected from at least one of azodicarbonamide, sodium bicarbonate and N,N'-dinitrospentamethylenetetramine; preferably azodicarbonamide.

9. The application of the foamed shoe sole material according to any one of claims 1-8, characterized in that, Without treatment agents, irradiation, or polishing, the foamed sole material is directly bonded to the outsole or upper.

Images