Soft non-slip rubber shoe material and preparation method thereof

Abstract

The invention relates to a soft non-slip rubber shoe material which comprises a rubber master batch, a mixture A and a mixture B, the rubber master batch comprises the following raw materials in percentage by mass: 20-35% of rare earth butadiene rubber, 10-25% of brominated butyl rubber, 5-12% of carboxy nitrile rubber, 5-10% of solution polymerized styrene-butadiene rubber, 5-10% of natural rubber and 3-5% of ethylene propylene diene monomer; the mixture A comprises the following raw materials in percentage by mass: 10%-15% of white carbon black, 2%-2.5% of polyethylene glycol, 2%-5% of softening oil, 3.5%-5% of a tackifier, 2%-3% of a coupling agent, 0.5%-1.0% of a lubricant, 1.5%-2.5% of zinc oxide, 0.4%-0.6% of an anti-aging agent and 0.4%-0.6% of an antioxidant; the mixture C comprises the following raw materials in percentage by mass: 1.5-2.5% of an accelerant and 2-3% of a cross-linking agent. The preparation method is simple, mild in processing condition and suitable for industrial production.

Description

Technical Field

[0001] The patent of this invention relates to the technical field of shoe materials, in particular to a soft non-slip rubber shoe material and a preparation method thereof. Background Art

[0002] Children are at a critical stage of growth and development, and their foot bones are soft and susceptible to damage. Soft, comfortable soles adapt to the natural shape of children's feet, ensuring healthy foot growth. Traditional rubber soles currently on the market are generally hard and stiff, failing to effectively conform to the natural curvature of the foot. This can easily lead to foot fatigue and is not suitable for children. Furthermore, the anti-slip properties of traditional rubber soles need to be further improved. On wet, slippery, or icy surfaces, they can easily cause children to slip, posing a safety hazard.

[0003] For sports shoes that play a role in sports competition, the research direction of their rubber soles is mainly to pursue wear resistance and anti-slip properties. Based on the need for sports support, this type of rubber soles is relatively hard and not comfortable, and is not suitable for use as children's soles.

[0004] Therefore, it is necessary to develop a children's shoe sole that is soft, comfortable and has good anti-slip effect. Summary of the Invention

[0005] The purpose of the present invention is to solve the existing technical problems and propose a soft non-slip rubber shoe material and a preparation method thereof. The soft non-slip rubber shoe material has suitable softness and excellent anti-wet and anti-slip properties on icy surfaces; the preparation method is simple, the processing conditions are mild, and it is suitable for industrial production.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: a soft non-slip rubber shoe material, comprising a masterbatch, a mixture A and a mixture B;

[0007] The masterbatch comprises the following raw materials in percentage by mass: 20% to 35% of rare earth cis-1,4-butadiene rubber, 10% to 25% of bromobutyl rubber, 5% to 12% of carboxylated nitrile rubber, 5% to 10% of solution-polymerized styrene-butadiene rubber, 5% to 10% of natural rubber, and 3% to 5% of EPDM rubber;

[0008] Mixture A includes the following raw materials in percentage by mass: 10% to 15% white carbon black, 2% to 2.5% polyethylene glycol, 2% to 5% softening oil, 3.5% to 5% tackifier, 2% to 3% coupling agent, 0.5% to 1.0% lubricant, 1.5% to 2.5% zinc oxide, 0.4% to 0.6% antioxidant, and 0.4% to 0.6% antioxidant;

[0009] Mixture C includes the following raw materials in percentage by mass: 1.5% to 2.5% of accelerator and 2% to 3% of cross-linking agent.

[0010] Preferably, the soft non-slip rubber shoe material has a hardness of 50±2A, a density of 1.1±0.1 g / cm3, and a tensile strength>9 MPa.

[0011] Preferably, the soft anti-slip rubber shoe material has a dynamic wet anti-slip coefficient of ≥0.40 and an ice anti-slip coefficient of ≥0.30.

[0012] Preferably, the white carbon black is fumed silica, and the specific surface area of ​​fumed silica is 210±25m 2 / g.

[0013] Furthermore, the model of the fumed silica is HP-200.

[0014] Preferably, the Mooney viscosity of the rare earth butadiene rubber is 40-70ML(1+4)125°C.

[0015] Furthermore, the rare earth butadiene rubber is one or both of CB22 and CB24.

[0016] Preferably, the Mooney viscosity of the brominated butyl rubber is 46±5ML(1+4)125°C.

[0017] Furthermore, the halogen content of the brominated butyl rubber is 1.8%, and the model of the brominated butyl rubber is BIIR X2.

[0018] Preferably, the mass fraction of acrylonitrile in the carboxylated nitrile rubber is 25-35%, and the Mooney viscosity is 40-55 ML (1+4) 125°C.

[0019] Furthermore, the model of the carboxylated nitrile rubber is one or both of XNBR1072 and XNBR3245C.

[0020] Preferably, the Mooney viscosity of the solution-polymerized styrene-butadiene rubber is 47±5ML(1+4)125°C.

[0021] Furthermore, the solution-polymerized styrene-butadiene rubber can be selected from PR-1205 with a styrene content of 25%.

[0022] Preferably, the Mooney viscosity of the EPDM rubber is 60±5ML(1+4)125°C.

[0023] Furthermore, the EPDM rubber contains 9% of a third monomer.

[0024] A method for preparing a soft non-slip rubber shoe material comprises the following steps:

[0025] S1: Add the masterbatch into the internal mixer according to the formula ratio and mix evenly; the initial temperature of the internal mixer is 90-100℃, and mix for 5-8 minutes to obtain the masterbatch;

[0026] S2: Add the mixed material A into the mixed masterbatch according to the formula ratio; the mixing time is 2 to 5 minutes. When the temperature of the rubber material reaches 120 to 150 ° C, the rubber is discharged and the sheet is discharged by the open mill. The sheet is parked for 24 hours and used as the mixed rubber sheet for standby;

[0027] S3: Mixture B and the mixed film obtained in S2 are mixed evenly in an open mill to obtain a sample film; the mixing temperature is 60±5°C and the mixing time is 10-15 minutes;

[0028] S4: Cut the sample film obtained in S3 and then hot-press it on a flat vulcanizer to produce a sole sample; the vulcanization temperature is 150-170° C., and the vulcanization time is 220-260 seconds.

[0029] The beneficial effects of the present invention are:

[0030] A soft anti-slip rubber used for shoe sole materials is obtained through the synergistic effect of rare earth cis-1,4-butadiene rubber, brominated butyl rubber, carboxyl nitrile rubber, solution-polymerized styrene-butadiene rubber, natural rubber and EPDM rubber.

[0031] Among them, brominated butyl rubber molecules contain active bromine, and nitrile rubber molecules contain cyanide. These two rubbers have strong polarity and produce strong intermolecular forces with water molecules, effectively improving the material's anti-slip performance. Combined with rare earth butyl rubber with excellent wear resistance and natural rubber with excellent low-temperature softness, the material's softness and wear resistance are improved. The solution-polymerized styrene-butadiene rubber in the formula has good comprehensive performance, and EPDM rubber has excellent anti-cracking performance. The fumed silica has a good reinforcement effect. The above materials are organically combined through chemical bonds to obtain a rubber material for children's soles with high softness and excellent anti-slip properties on ice and wet surfaces.

[0032] The brominated butyl rubber used in the present invention also has high damping and a low glass transition temperature. The high damping consumes a large amount of deformation energy and then generates a strong hysteresis friction force, while the low glass transition temperature ensures that the rubber can effectively fit the contact surface under a wide range of temperatures, thereby maximizing the frictional contact between the rubber and the contact surface.

[0033] The carboxyl nitrile rubber used in the present invention contains highly polar cyano and carboxyl groups in its molecular chain, which increases wet friction resistance through intermolecular forces with water molecules, thereby improving anti-slip performance.

[0034] The rare earth cis-1,2-butadiene rubber used in the present invention is neodymium-based cis-1,2-butadiene rubber, which is a high-cis cis-1,2-butadiene rubber polymerized with rare earth metal neodymium as the main catalyst system, with a cis content of more than 98%. Its relatively narrow molecular weight distribution and low degree of branching effectively improve the wear resistance of the rubber sole material.

[0035] The natural rubber molecular structure used in the present invention is mainly composed of polyisoprene, and its molecular chain is a chain structure. The molecular chain is flexible and can be easily deformed, so it has excellent low-temperature softness, which can effectively improve the comfort of the sole material. When it is subjected to pressure at low temperatures (for example, when stepped on), it can still increase the effective contact area with the ground through deformation, thereby improving the anti-slip performance.

[0036] The solution-polymerized styrene-butadiene rubber used in the present invention is a linearly arranged butadiene / styrene copolymer with high molecular weight and narrow molecular weight distribution. The styrene in the molecular structure provides rigidity and the butadiene provides flexibility, so that it has excellent elasticity, wear resistance and wet-slip resistance.

[0037] The EPDM rubber used in the present invention is a copolymer of ethylene, propylene and non-conjugated dienes. The main chain in its molecular structure is a saturated hydrocarbon chain. This property enables it to effectively resist corrosion from heat, light, oxygen and ozone, thereby improving the aging resistance and anti-cracking properties of the sole material.

[0038] The silica used in this invention is fumed silica. Compared to traditional precipitated silica, fumed silica has smaller particle size, larger specific surface area, stronger surface adsorption, higher surface energy, and better dispersibility, resulting in superior reinforcing properties. The addition of a small amount of fumed silica effectively improves the softness of the sole.

[0039] The soft non-slip rubber sole material prepared according to the formula of the present invention can still maintain a dynamic wet anti-slip coefficient of ≥0.40, an ice anti-slip coefficient of ≥0.30, a footwear wear resistance of ≤10mm, and a rubber wear resistance of ≤155mm when its hardness is 50±2A after testing. 3 、Density 1.1±0.1g / cm 3 The material exhibits excellent properties, including tensile strength >9MPa, right-angle tear strength ≥40N / mm, yellowing resistance ≥3-4, and no cracking in ozone resistance tests. Compared to current rubber sole materials in the industry, which typically have a hardness of 55-65A, a dynamic wet skid resistance coefficient of only 0.25, and an ice skid resistance coefficient of less than 0.3, the sole rubber material obtained by the present invention is both soft and comfortable while also offering both ice and wet skid resistance.

[0040] At the same time, the preparation method of the present invention is simple, the processing conditions are mild, and it is suitable for industrial production. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0042] A method for preparing a soft non-slip rubber shoe material comprises the following steps:

[0043] S1: Add the masterbatch into the internal mixer according to the formula ratio and mix evenly; the initial temperature of the internal mixer is 90-100℃, and mix for 5-8 minutes to obtain the masterbatch;

[0044] S2: Add the mixed material A into the mixed masterbatch according to the formula ratio; the mixing time is 2 to 5 minutes. When the temperature of the rubber material reaches 120 to 150 ° C, the rubber is discharged and the sheet is discharged by the open mill. The sheet is parked for 24 hours and used as the mixed rubber sheet for standby;

[0045] S3: Mixture B and the mixed film obtained in S2 are mixed evenly in an open mill to obtain a sample film; the mixing temperature is 60±5°C and the mixing time is 10-15 minutes;

[0046] S4: Cut the sample film obtained in S3 and then hot-press it on a flat vulcanizer to produce a sole sample; the vulcanization temperature is 150-170° C., and the vulcanization time is 220-260 seconds.

[0047] Table 1 Raw material formula of the sole samples of Examples 1-7

[0048] raw materials Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Rare earth butadiene rubber CB24 35％ 30％ 25％ 20％ 31％ 22％ 21％ Bromobutyl rubber BIIR X2 10％ 15％ 20％ 25％ 20％ 15％ 15％ Carboxylated nitrile rubber XNBR3245C 8％ 8％ 8％ 8％ 5％ 8％ 12％ Natural rubber 3L 7％ 7％ 7％ 7％ 5％ 10％ 5％ Solution polymerized styrene butadiene rubber PR-1205 6％ 6％ 6％ 6％ 5％ 10％ 5％ EPDM 9950C 3％ 3％ 3％ 3％ 5％ 5％ 5％ Fumed silica HP-200 12％ 12％ 12％ 12％ 10％ 10％ 15％ Polyethylene glycol PEG4000 2％ 2％ 2％ 2.2％ 2％ 2.5％ 2％ Softening oil 4006 2.5％ 2％ 2％ 2％ 2％ 3％ 5％ Tackifier PR-803 3.5％ 4％ 4.5％ 4％ 5％ 4％ 4％ Coupling agent SI-75 2.5％ 3％ 2％ 2.3％ 2％ 2％ 2.5％ Lubricant ST 0.5％ 0.8％ 0.6％ 0.5％ 0.6％ 0.6％ 1.0％ Zinc oxide ZNO 2.5％ 1.5％ 2.5％ 2％ 1.5％ 1.5％ 1.6％ Antioxidant SP 0.4％ 0.5％ 0.6％ 0.5％ 0.5％ 0.5％ 0.5％ Antioxidant BHT 0.6％ 0.5％ 0.4％ 0.5％ 0.5％ 0.5％ 0.5％ Accelerator D 0.8％ 0.9％ 0.8％ 0.9％ 0.8％ 0.8％ 0.8％ Accelerator DM 1.1％ 1.3％ 1.5％ 1.5％ 1.5％ 1.5％ 1.5％ Accelerator TS 0.1％ 0.1％ 0.1％ 0.1％ 0.1％ 0.1％ 0.1％ Crosslinking agent S-80 2.5％ 2.4％ 2％ 2.5％ 2.5％ 3％ 2.5％

[0049] According to the formulation in Table 1, the sole samples of Examples 1-7 were obtained by the above preparation method; wherein the softening oil was naphthenic oil 4006, the tackifier was highly hydrogenated petroleum resin PR-803 (ENEOS, Japan); the accelerators included accelerator D, accelerator DM, and accelerator TS; and the crosslinking agent was sulfur S-80.

[0050] Table 2 Raw material formula of the sole samples of comparative examples 1-10

[0051]

[0052] According to the formulation in Table 2, the shoe sole samples of Comparative Examples 1-10 were obtained by the above-described preparation method. The rare earth cis-1,1-butadiene rubber, bromobutyl rubber, carboxylated nitrile rubber, EPDM rubber, fumed silica, and polyethylene glycol were the same as those in Table 1; the cis-1,1-butadiene rubber model was BR9000, the nitrile rubber model was 4155, and the precipitated silica model was JS-260.

[0053] The sole samples obtained from Examples 1-7 and Comparative Examples 1-10 were tested for hardness (GB / T3903.4-2017), density (GB / T533-2008), rubber wear resistance (GB / T 9867-2008), footwear wear resistance (GB / T3903.2-2017), dry anti-slip coefficient (GB / T3903.6-2017), wet anti-slip coefficient (GB / T3903.6-2017), ice anti-slip coefficient (SATRA TM144:2021), tensile strength (GB / T528-2009), elongation at break (GB / T528-2009), tear strength (GB / T529-2009), yellowing resistance (HG / T3689-2014), ozone cracking resistance test (GB / T7762-2014, temperature 40°C, humidity 65%, ozone concentration 50pphm, time 24H), the test results are shown in Tables 3 and 4.

[0054] Table 3 Performance test results of sole samples of Examples 1-7

[0055]

[0056] It can be seen from the test results of Examples 1-4 that as the amount of rare earth cis-1,4-butadiene rubber added decreases, the amount of brominated butyl rubber added increases, and the anti-wet and ice anti-skid performance of the obtained rubber sole sample improves, but the wear resistance deteriorates. Mainly because the extremely high cis content, quite narrow molecular weight distribution and relatively low degree of branching of rare earth cis-1,4-butadiene rubber effectively improve the wear resistance of the rubber sole material; and brominated butyl rubber molecules have high polarity, high damping and low glass transition temperature, and high damping consumes a large amount of deformation energy and then produces powerful hysteresis friction, and low glass transition temperature ensures that rubber can effectively fit the contact surface at a wide range of temperatures, so that rubber and contact surface maximize friction contact. Therefore, the present invention achieves a balance between the anti-skid performance and wear resistance of the sole material by rationally matching the amount of rare earth cis-1,4-butadiene rubber and brominated butyl rubber.

[0057] Table 4 Comparative Examples 1-10 Sole Sample Performance Test Results

[0058]

[0059] Comparing the performance test results of the sole samples in Table 3 and Table 4, it can be seen that the overall physical and mechanical properties of the rubber sole prepared in Example 3 are more balanced, the sole hardness is soft, and the anti-skid effect on ice and wet surface is excellent (at the same time, the dynamic wet anti-skid coefficient is ≥0.40 and the anti-skid coefficient on ice is ≥0.30). At the same time, other performance test results such as rubber wear resistance meet the needs of children's daily wear.

[0060] The performance test results of Comparative Example 1 and Example 3 show that when the rare earth cis-1,4-butadiene rubber in the formula is replaced with ordinary cis-1,4-butadiene rubber, the wear resistance of the prepared rubber sole is significantly reduced. This is mainly because rare earth cis-1,4-butadiene rubber has a higher cis structure content than ordinary cis-1,4-butadiene rubber, giving the molecular chain a highly stereoregular structure, and thus outperforming traditional nickel-based cis-1,4-butadiene rubber in terms of wear resistance and tear strength.

[0061] The performance test results of Comparative Example 2 and Example 3 show that when the carboxylated nitrile rubber in the formula is replaced with ordinary nitrile rubber, the anti-slip performance of the prepared rubber sole is significantly reduced. This is mainly because the carboxylated nitrile rubber has a higher polarity and can form stronger intermolecular forces with the water film on the ground or ice surface.

[0062] The test data from Comparative Example 3 and Example 3 show that when precipitated silica is substituted for fumed silica in the formulation, the wear resistance and tear strength of the resulting rubber soles significantly decrease. This is primarily because fumed silica has a larger specific surface area, allowing it to better reinforce the rubber.

[0063] By the test data of comparative example 4 and embodiment 3, it is known that after the natural rubber in the formula is replaced by rare earth cis-1,4-butadiene rubber, prepared rubber sole wear resistance is improved significantly, but material softness and anti-skid performance decline significantly. Mainly because the natural rubber molecular chain has high flexibility, and extremely low glass transition temperature, the softness and viscosity of material can be effectively improved, the effective contact area of ​​material and ground can be increased, the anti-skid performance of material is improved. Main purpose of the present invention is to obtain a kind of both comfortable soft and non-slip rubber material, the relationship between the need to balance shoe material softness, anti-skid performance and wear resistance, it is ensured that the sole material physical property can meet the requirements, therefore the present invention selects rare earth cis-1,4-butadiene rubber to promote the wear resistance of material, and selects natural rubber to promote the softness and anti-skid performance of material.

[0064] It can be seen from the test data of Comparative Example 5 and Example 3 that when the solution-polymerized styrene-butadiene rubber in the formula is replaced with rare earth cis-1,4-dimethyl-1-butyl rubber, the wear resistance of the prepared rubber sole is improved, but the anti-slip performance of the material decreases, mainly because the solution-polymerized styrene-butadiene rubber has a regular molecular structure and a good molecular chain flexibility, which enables it to still maintain a higher elasticity at low temperatures. In a slippery environment, when the sole contacts the ground, good elasticity can make the sole fit closely with the ground when under pressure, increase the actual contact area, thereby improving friction and enhancing anti-slip performance. Therefore, the present invention selects rare earth cis-1,4-dimethyl-1-butyl rubber to improve the wear resistance of the material, and selects solution-polymerized styrene-butadiene rubber to improve the anti-slip performance of the material.

[0065] It can be seen from the test data of Comparative Example 6 and Example 3 that when the EPDM rubber in the formula is replaced with rare earth butadiene rubber, the wear resistance of the prepared rubber sole is improved, but the anti-cracking performance of the material is significantly reduced. This is mainly because the main chain in the molecular structure of EPDM rubber is a saturated hydrocarbon chain, which can effectively resist heat, light, oxygen, and especially ozone corrosion, thereby improving the aging resistance of the sole. Therefore, the present invention uses EPDM rubber to improve the anti-cracking and aging resistance of the material.

[0066] It can be seen from Comparative Examples 7-10 that when the mass percentage of the raw materials used in the comparative examples exceeds the set range of the formula, the comprehensive physical properties are significantly reduced, and the tested physical properties deviate to varying degrees.

[0067] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A soft non-slip rubber shoe material, characterized in that: Including masterbatch, mixture A and mixture B; The masterbatch comprises the following raw materials in percentage by mass: 20% to 35% of rare earth cis-1,4-butadiene rubber, 10% to 25% of bromobutyl rubber, 5% to 12% of carboxylated nitrile rubber, 5% to 10% of solution-polymerized styrene-butadiene rubber, 5% to 10% of natural rubber, and 3% to 5% of EPDM rubber; Mixture A includes the following raw materials in percentage by mass: 10% to 15% white carbon black, 2% to 2.5% polyethylene glycol, 2% to 5% softening oil, 3.5% to 5% tackifier, 2% to 3% coupling agent, 0.5% to 1.0% lubricant, 1.5% to 2.5% zinc oxide, 0.4% to 0.6% antioxidant, and 0.4% to 0.6% antioxidant; Mixture C includes the following raw materials in percentage by mass: 1.5% to 2.5% of accelerator and 2% to 3% of cross-linking agent.

2. The soft non-slip rubber shoe material according to claim 1, characterized in that: The hardness of the soft non-slip rubber shoe material is 50±2A and the density is 1.1±0.1g / cm 3 , tensile strength>9MPa.

3. The soft non-slip rubber shoe material according to claim 2, characterized in that: The soft anti-slip rubber shoe material has a dynamic wet anti-slip coefficient of ≥0.40 and an ice anti-slip coefficient of ≥0.

30.

4. The soft non-slip rubber shoe material according to claim 1, characterized in that: The white carbon black is fumed silica, and the specific surface area of ​​fumed silica is 210±25m 2 / g.

5. The soft non-slip rubber shoe material according to claim 1, characterized in that: The Mooney viscosity of the rare earth butadiene rubber is 40-70ML (1+4) at 125°C.

6. The soft non-slip rubber shoe material according to claim 1, characterized in that: The Mooney viscosity of the brominated butyl rubber is 46±5ML(1+4)125°C.

7. The soft non-slip rubber shoe material according to claim 1, characterized in that: The mass fraction of acrylonitrile in the carboxyl nitrile rubber is 25-35%, and the Mooney viscosity is 40-55ML(1+4)125°C.

8. The soft non-slip rubber shoe material according to claim 1, characterized in that: The Mooney viscosity of the solution-polymerized styrene-butadiene rubber is 47±5ML(1+4)125°C.

9. The soft non-slip rubber shoe material according to claim 1, characterized in that: The Mooney viscosity of the EPDM rubber is 60±5ML(1+4)125°C.

10. A method for preparing a soft non-slip rubber shoe material according to any one of claims 1 to 9, comprising the following steps: S1: Add the masterbatch into an internal mixer according to the formula ratio and mix evenly; the initial temperature of the internal mixer is 90-100℃, and mix for 5-8 minutes to obtain the masterbatch; S2: Add the mixed material A into the mixed masterbatch according to the formula ratio; the mixing time is 2 to 5 minutes. When the temperature of the rubber material reaches 120 to 150 ° C, the rubber is discharged and the sheet is discharged by the open mill. The sheet is parked for 24 hours and used as the mixed rubber sheet for standby; S3: Mixture B and the mixed film obtained in S2 are mixed evenly in an open mill to obtain a sample film; the mixing temperature is 60±5°C and the mixing time is 10-15 minutes; S4: Cut the sample film obtained in S3 and then hot-press it on a flat vulcanizer to produce a sole sample; the vulcanization temperature is 150-170° C., and the vulcanization time is 220-260 s.

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