Synthetic rubber material for thin-sole shoe material and preparation method of synthetic rubber material

Abstract

The invention relates to the technical field of modification of rubber and plastic materials in shoe materials, in particular to a synthetic rubber material for a thin-sole shoe material and a preparation method of the synthetic rubber material. According to the invention, two kinds of specific thermoplastic styrene-butadiene rubber are compounded with the polyolefin elastomer, so that the obtained synthetic rubber has high elasticity and high wear resistance; through the synergistic effect of the flexibilizer and the compatilizer, the synthetic rubber has good adhesive tension, and the problems of degumming, glue failure and the like when the synthetic rubber is applied to shoe soles are prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of modification of rubber and plastic materials in shoe materials, and in particular to a synthetic rubber material for thin-soled shoes and a preparation method thereof. Background Art

[0002] Polyvinyl chloride (PVC) and vulcanized rubber are two major sources of shoe materials. PVC, with its low production cost, is commonly used in the production of low-cost footwear such as slippers, sandals, and rain boots. Vulcanized rubber, a traditional shoe material, is commonly used in footwear requiring high wear resistance and elasticity, such as athletic shoes and hiking boots.

[0003] However, PVC produces toxic substances such as vinyl chloride monomer (VCM) and dioxins during its production and disposal process, which pollute the environment. The improved wear resistance of vulcanized rubber after vulcanization is also its drawback. Vulcanization significantly increases production and recycling costs. Furthermore, vulcanized rubber has a high density, making the resulting soles, while wear-resistant, very thick and heavy. Lightweighting is a key characteristic in the preparation of thin-soled shoe materials, and vulcanized rubber presents significant challenges in this regard.

[0004] To address the numerous issues that arise with PVC and vulcanized rubber in thin-soled shoe applications, researchers have turned their attention to materials such as thermoplastic elastomers (TPE), thermoplastic polyurethanes (TPU), and thermoplastic rubbers (TPR). Compared to PVC and vulcanized rubber, TPE has a lower density and is free of halogens and heavy metals, while still offering excellent elasticity and wear resistance. Similarly, TPU and TPR also offer good elasticity and wear resistance, and their production process produces no toxic substances, while TPR is also low-cost.

[0005] However, when TPE is used as a thin-soled shoe material, it is found to have poor adhesion and tensile strength, making it prone to debonding. Generally speaking, the use of a single material will have application limitations in some areas; therefore, modifying and compounding single materials is necessary to achieve thin-soled shoe materials with more comprehensive performance. Summary of the Invention

[0006] The present invention provides a synthetic rubber material for thin-soled shoes and a preparation method thereof. The synthetic rubber material for thin-soled shoes can achieve higher elasticity than TPR material, higher hardness than TPE material, and has good peel strength.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] The present invention provides a synthetic rubber material for thin-soled shoes, which comprises, by weight:

[0009] Polyolefin elastomer: 5-15 parts,

[0010] The first thermoplastic styrene-butadiene rubber: 30-45 parts,

[0011] Second thermoplastic styrene-butadiene rubber: 30-45 parts,

[0012] Compatibilizer: 3-10 parts,

[0013] Toughening agent: 5-10 parts,

[0014] Antioxidant: 0.1-5 parts,

[0015] Inorganic filler: 5 to 20 parts.

[0016] This application uses a compound of thermoplastic styrene-butadiene rubber (TPR) and polyolefin elastomer (POE) to replace PVC or vulcanized rubber, which is greener and safer. TPR, a type of styrene-based plastic (TPR), boasts high hardness and excellent wear resistance; POE, a type of TPE, exhibits excellent elasticity and toughness. The compound of TPR and PPE combines the properties of TPR and TPE to create a matrix that is both elastic and wear-resistant.

[0017] On this basis, a compatibilizer, a toughening agent, an inorganic filler, and an antioxidant are added to balance the other properties of the entire synthetic rubber system, resulting in the synthetic rubber material for thin-soled shoes exhibiting high elasticity, high wear resistance, strong adhesive tension, and aging resistance, meeting the performance requirements of thin-soled shoes for raw materials. The thin-soled shoes made from the synthetic rubber material for thin-soled shoes provided in this application exhibit a long service life and are light and comfortable to wear.

[0018] The specific raw materials in the specific content in this application support and cooperate with each other in terms of function, which can improve the comprehensive performance of the synthetic rubber material for thin-soled shoes.

[0019] Preferably, the compatibilizer includes at least a maleic anhydride grafted compatibilizer.

[0020] More preferably, the maleic anhydride grafted compatibilizer is one or more of maleic anhydride grafted SBS, maleic anhydride grafted SEBS, maleic anhydride grafted EPDM, maleic anhydride grafted PP, maleic anhydride grafted POE and maleic anhydride grafted TPE.

[0021] More preferably, the compatibilizer is maleic anhydride grafted SBS.

[0022] The compatibilizer can aid in mixing the polyolefin elastomer, the first thermoplastic styrene butadiene rubber, the second thermoplastic styrene butadiene rubber, and the inorganic filler.

[0023] Preferably, the toughening agent comprises at least ethylene-vinyl acetate copolymer.

[0024] More preferably, the toughening agent is ethylene-vinyl acetate copolymer and / or maleic anhydride grafted EVA.

[0025] More preferably, the toughening agent is ethylene-vinyl acetate copolymer.

[0026] Toughening agents help improve the toughness and flexibility of synthetic rubber. At the same time, the combined use of toughening agents and compatibilizers can help improve the bonding tension of synthetic rubber, allowing synthetic rubber to be tightly bonded to the upper when used as a sole material, preventing degumming and opening, which affects the life of the shoes.

[0027] Preferably, the inorganic filler is one or more of calcium carbonate, magnesium carbonate, barium sulfate, talc, wollastonite, and white carbon black.

[0028] Preferably, the inorganic filler is white carbon black.

[0029] Preferably, the particle size of the inorganic filler is 20 to 50 nm.

[0030] Preferably, the antioxidant is one or more of antioxidant 1010 , antioxidant 168 and antioxidant 1076 .

[0031] Preferably, it further comprises 0 to 3 parts of lubricant, 0 to 2 parts of plasticizer and 0 to 3 parts of colorant.

[0032] Preferably, the first thermoplastic styrene butadiene rubber is a styrene-butadiene-styrene block copolymer of model SBS3546, and the second thermoplastic styrene butadiene rubber is a styrene-butadiene-styrene block copolymer of model SBS1475.

[0033] The present invention also provides a method for preparing the above-mentioned synthetic rubber material for thin-soled shoe materials, comprising: weighing a polyolefin elastomer, a first thermoplastic styrene-butadiene rubber, a second thermoplastic styrene-butadiene rubber, a compatibilizer, a toughening agent, an antioxidant and an inorganic filler, kneading and mixing them, then extruding and pelletizing them, and air-cooling them to obtain a composite material A; melt-kneading the composite material A, then extruding, sheeting, cooling, cutting and roughening them to obtain the synthetic rubber material for thin-soled shoe materials.

[0034] The present invention also provides a method for preparing the above-mentioned synthetic rubber material for thin-soled shoe materials, comprising: weighing a first thermoplastic styrene-butadiene rubber and a second thermoplastic styrene-butadiene rubber and stirring them evenly, then adding a polyolefin elastomer, a compatibilizer, a toughening agent, an antioxidant and an inorganic filler, stirring them evenly again, then extruding and pelletizing, and air-cooling to obtain a composite material B; melt-kneading the composite material B, then extruding, sheeting, cooling, cutting, and roughening to obtain the synthetic rubber material for thin-soled shoe materials.

[0035] Therefore, the present invention has the following beneficial effects:

[0036] (1) The present invention selects two specific thermoplastic styrene-butadiene rubbers and polyolefin elastomers to compound, thereby ensuring that the obtained synthetic rubber has both high elasticity and high wear resistance; and through the synergistic effect of the toughening agent and the compatibilizer, the synthetic rubber is ensured to have good bonding tension, thereby preventing problems such as degumming and opening when used in the soles of shoes.

[0037] (2) The synthetic rubber obtained by the present invention has multiple properties such as good flexibility, good toughness, high elasticity, high strength, and high wear resistance. It can also ensure the wearing comfort and wearing life of the shoes when preparing thin-soled shoes, and has good application prospects in the direction of thin-soled shoe materials.

[0038] (3) The synthetic rubber obtained by the present invention can achieve higher elasticity than TPR material and higher hardness than TPE material, and at the same time has better peel strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of mixing process 1;

[0040] Figure 2 Schematic diagram of mixing process 2;

[0041] Figure 3 Schematic diagram of the preparation process of thin-soled shoe materials. DETAILED DESCRIPTION

[0042] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below generally represent only a portion of the present invention, rather than all of the embodiments. Therefore, all other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0043] Materials in this section: SBS3546, styrene-butadiene-styrene block copolymer, thermoplastic styrene-butadiene rubber, purchased from Dongguan Suwei New Materials Co., Ltd.; SBS1475, styrene-butadiene-styrene block copolymer, thermoplastic styrene-butadiene rubber, purchased from Dongguan Bailing New Materials Co., Ltd.; SBS YH-792, styrene-butadiene-styrene block copolymer, thermoplastic styrene-butadiene rubber, purchased from Dongguan Shuo Plastic Raw Materials Co., Ltd.; SBS4452, styrene-butadiene-styrene block copolymer, thermoplastic styrene-butadiene rubber, purchased from Shanghai Jingying Materials Co., Ltd.; POE, polyolefin elastomer, Dow ENGAGE 8480, purchased from Dongguan Shuo Plastic Raw Materials Co., Ltd.; EVA, ethylene-vinyl acetate copolymer, VA910, Lotte, South Korea, purchased from Shanghai Huihang New Materials Co., Ltd.; white carbon black, CAS10279-57-9, purchased from Shanghai Yuanye Biotechnology Co., Ltd.; maleic anhydride grafted SBS, CAS112-84-5, purchased from Dongguan Bailing New Materials Co., Ltd.; antioxidant 1010, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropionate, purity 98%, purchased from Shanghai Yuanye Biotechnology Co., Ltd.; antioxidant 168, tris(2,4-di-tert-butyl)phenyl phosphite, purity 98%, purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0044] [Example]

[0045] Example 1

[0046] The formula was weighed in parts by mass: 32 parts of SBS3546, 35 parts of SBS1475, 9.3 parts of POE, 6.4 parts of EVA, 11.7 parts of white carbon black (30 nm), 5 parts of maleic anhydride grafted SBS, 0.3 parts of antioxidant 1010, and 0.3 parts of antioxidant 168.

[0047] like Figure 1 As shown, when the mixer temperature reaches 90°C, open the mixer and add all the ingredients according to the above formula. After mixing into a dough, turn the mixture over and pressurize and mix until the mixer temperature reaches 120°C. The mixed material is added to the forced feeding granulator and the forced feeding granulator temperature is set as follows: 90°C for the first stage, 110°C for the second stage, 100°C for the third stage, and 140°C-150°C for the fourth stage. The mixture is extruded and pelletized, and then passes through two stages of air cooling before flowing into a vibrating screen. After the particles are shaken and cooled again, they are bagged and packaged.

[0048] like Figure 3As shown, the obtained mixed granules are fed into a perforated wire extruder (i.e., a sleeve outside the screw has vent holes on it to remove moisture from the rubber compound). The sheet is then extruded through a die head and rolled through a mold to obtain a sheet of the desired thickness. The sheet is then pulled through a tractor and cut into the desired lengths by an automatic cutter. After being arranged and naturally cooled, the cooled sheet is placed in a cutting machine, where a die is used to cut the thin sole material into the desired shape. The cut thin sole is then placed in an automatic roughing machine, where it is roughened on both sides to obtain the final thin-soled shoe material.

[0049] Example 2

[0050] The formula was weighed in parts by mass: 40.1 parts of SBS3546, 30.9 parts of SBS1475, 5.2 parts of POE, 6.5 parts of EVA, 11.7 parts of white carbon black (30 nm), 5 parts of maleic anhydride grafted SBS, 0.3 parts of antioxidant 1010, and 0.3 parts of antioxidant 168.

[0051] like Figure 2 As shown, according to the above formula, SBS1475 and SBS3546 are weighed and put into a high-speed stirring barrel. The temperature is set at 80℃. When the temperature reaches 80℃, stirring is stopped. All the remaining raw materials in the above formula are added to the high-speed stirring barrel, and the high-speed stirring barrel is restarted to mix for 5-10 seconds. Subsequently, the discharged material is added to the twin-screw extruder granulator. The temperature of the twin-screw extruder granulator is set as follows: 80℃ for the first section, 100℃ for the second section, 120℃ for the third section, 120℃ for the fourth section, 100℃ for the fifth section, 80℃ for the sixth section, 80℃ for the seventh section, and 120℃ for the eighth section. The extruded pellets are then air-cooled in two sections and flow into a horizontal stirring cooling barrel. After cooling, they are bagged for later use.

[0052] like Figure 3 As shown, the obtained mixed granules are fed into a perforated wire extruder (i.e., a sleeve outside the screw has vent holes on it to remove moisture from the rubber compound). The sheet is then extruded through a die head and rolled through a mold to obtain a sheet of the desired thickness. The sheet is then pulled through a tractor and cut into the desired lengths by an automatic cutter. After being arranged and naturally cooled, the cooled sheet is placed in a cutting machine, where a die is used to cut the thin sole material into the desired shape. The cut thin sole is then placed in an automatic roughing machine, where it is roughened on both sides to obtain the final thin-soled shoe material.

[0053] Comparative Example 1 (without SBS)

[0054] This comparative example is substantially the same as Example 1, except that:

[0055] The formula was weighed in parts by mass: 76.3 parts of POE, 6.4 parts of EVA, 11.7 parts of white carbon black (30 nm), 5 parts of maleic anhydride grafted SBS, 0.3 parts of antioxidant 1010, and 0.3 parts of antioxidant 168.

[0056] Comparative Example 2 (without POE)

[0057] This comparative example is substantially the same as Example 1, except that:

[0058] The formula was weighed in parts by mass: 41.3 parts of SBS3546, 35 parts of SBS1475, 6.4 parts of EVA, 11.7 parts of white carbon black (30 nm), 5 parts of maleic anhydride grafted SBS, 0.3 parts of antioxidant 1010, and 0.3 parts of antioxidant 168.

[0059] Comparative Example 3 (without EVA)

[0060] This comparative example is substantially the same as Example 1, except that:

[0061] The formula was weighed in parts by mass: 32 parts of SBS3546, 35 parts of SBS1475, 9.3 parts of POE, 11.7 parts of white carbon black (30 nm), 11.4 parts of maleic anhydride grafted SBS, 0.3 parts of antioxidant 1010, and 0.3 parts of antioxidant 168.

[0062] Comparative Example 4 (no maleic anhydride grafted SBS)

[0063] This comparative example is substantially the same as Example 1, except that:

[0064] The formula was weighed in parts by mass: 32 parts of SBS3546, 35 parts of SBS1475, 9.3 parts of POE, 11.4 parts of EVA, 11.7 parts of white carbon black, 0.3 parts of antioxidant 1010, and 0.3 parts of antioxidant 168.

[0065] Comparative Example 5

[0066] This comparative example is substantially the same as Example 1, except that:

[0067] According to mass, weigh 67 parts of SBS3546, 9.3 parts of POE, 6.4 parts of EVA, 11.7 parts of white carbon black (30nm), 5 parts of maleic anhydride grafted SBS, 0.3 parts of antioxidant 1010, and 0.3 parts of antioxidant 168.

[0068] Comparative Example 6

[0069] This comparative example is substantially the same as Example 1, except that:

[0070] The formula was weighed in parts by mass: 32 parts of SBS YH-792, 35 parts of SBS1475, 9.3 parts of POE, 6.4 parts of EVA, 11.7 parts of white carbon black (30 nm), 5 parts of maleic anhydride grafted SBS, 0.3 parts of antioxidant 1010, and 0.3 parts of antioxidant 168.

[0071] Comparative Example 7

[0072] This comparative example is substantially the same as Example 1, except that:

[0073] The formula was weighed in parts by mass: 32 parts of SBS YH-792, 35 parts of SBS4452, 9.3 parts of POE, 6.4 parts of EVA, 11.7 parts of white carbon black (30 nm), 5 parts of maleic anhydride grafted SBS, 0.3 parts of antioxidant 1010, and 0.3 parts of antioxidant 168.

[0074]

Performance test

[0075] Table 1 Physical properties of various embodiments / comparative examples

[0076]

[0077] From the data in Table 1, it can be seen that after compounding SBS and POE, the base material has both elasticity and wear resistance. However, when it lacks the effects of compatibilizers and toughening agents, it cannot achieve a high peel strength, making it unsuitable for use in a wide range of footwear products. After adding EVA and maleic anhydride grafted SBS, the compounding of the two synergistically increases the adhesion of the SBS / POE matrix. At the same time, this application screened multiple types of SBS for compounding and found that only when the SBS3546 and SBS1475 screened by this application were combined, balanced elasticity and wear resistance were exhibited. Otherwise, a thin-soled shoe material with balanced performance could not be obtained.

Claims

1. A synthetic rubber material for thin-soled shoes, characterized in that: Calculated by mass, including: Polyolefin elastomer: 5-15 parts, The first thermoplastic styrene-butadiene rubber: 30-45 parts, Second thermoplastic styrene-butadiene rubber: 30-45 parts, Compatibilizer: 3-10 parts, Toughening agent: 5-10 parts, Antioxidant: 0.1-5 parts, Inorganic filler: 5 to 20 parts.

2. The synthetic rubber material for thin-soled shoes according to claim 1, wherein: The compatibilizer at least includes a maleic anhydride grafted compatibilizer.

3. The synthetic rubber material for thin-soled shoes according to claim 1, wherein: The toughening agent at least includes ethylene-vinyl acetate copolymer.

4. The synthetic rubber material for thin-soled shoes according to claim 1, wherein: The inorganic filler is one or more of calcium carbonate, magnesium carbonate, barium sulfate, talc, wollastonite, and white carbon black.

5. The synthetic rubber material for thin-soled shoes according to claim 1, wherein: The particle size of the inorganic filler is 20 to 50 nm.

6. The synthetic rubber material for thin-soled shoes according to claim 1, wherein: The antioxidant is one or more of antioxidant 1010 , antioxidant 168 and antioxidant 1076 .

7. The synthetic rubber material for thin-soled shoes according to any one of claims 1 to 6, characterized in that: It also includes 0 to 3 parts of lubricant, 0 to 2 parts of plasticizer and 0 to 3 parts of colorant.

8. The synthetic rubber material for thin-soled shoes according to any one of claims 1 to 6, characterized in that: The first thermoplastic styrene butadiene rubber is a styrene-butadiene-styrene block copolymer of model SBS3546, and the second thermoplastic styrene butadiene rubber is a styrene-butadiene-styrene block copolymer of model SBS1475.

9. The method for preparing a synthetic rubber material for thin-soled shoes according to any one of claims 1 to 8, characterized in that: include: A polyolefin elastomer, a first thermoplastic styrene-butadiene rubber, a second thermoplastic styrene-butadiene rubber, a compatibilizer, a toughening agent, an antioxidant and an inorganic filler are weighed and mixed, and then extruded, pelletized and air-cooled to obtain a composite material A; the composite material A is melt-kneaded, and then extruded, sheeted, cooled, cut into pieces and roughened to obtain a synthetic rubber material for thin-soled shoes.

10. The method for preparing a synthetic rubber material for thin-soled shoes according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: weighing a first thermoplastic styrene-butadiene rubber and a second thermoplastic styrene-butadiene rubber and stirring them evenly; then adding a polyolefin elastomer, a compatibilizer, a toughening agent, an antioxidant and an inorganic filler; stirring them evenly again; then extruding, pelletizing and air-cooling to obtain a composite material B; and melting and kneading the composite material B, then extruding, tableting, cooling, cutting and roughening to obtain a synthetic rubber material for thin-soled shoes.

Images