A transparent rubber outsole that is resistant to wet slip and ozone and its preparation method

Abstract

This invention provides a transparent rubber outsole that is wet-slip and ozone-resistant, prepared from the following raw materials: 75-90 parts by weight of primary form of polyurethane; 10-25 parts by weight of trans-butadiene rubber; 5-10 parts by weight of low molecular weight polyisobutylene; 5-10 parts by weight of maleic anhydride-modified liquid polybutadiene; 30-35 parts by weight of transparent silica; 2-3 parts by weight of methyl vinyl silicone oil; 3-5 parts by weight of paraffin oil; 1-1.5 parts by weight of nano-active zinc oxide; 1-2 parts by weight of polyethylene glycol; 0.3-0.5 parts by weight of stearic acid; 0.5-1.0 parts by weight of antioxidant; 0.5-1 part by weight of light stabilizer; 0-1 part by weight of pigment; and 0.5-0.7 parts by weight of peroxide crosslinking agent. The wet-slip and ozone-resistant transparent rubber outsole provided by this invention not only possesses excellent ozone crack resistance, slip resistance, and abrasion resistance, but also meets the mechanical performance indicators of rubber shoe soles.

Description

Technical Field

[0001] This invention relates to the field of transparent rubber technology, and more specifically, to a wet-slip and ozone-resistant transparent rubber outsole and its preparation method. Background Technology

[0002] Existing transparent rubbers are generally selected from one or a combination of six types of rubber: butadiene rubber, isoprene rubber, solution-polymerized styrene-butadiene rubber, EPDM rubber, methyl silicone rubber, and MPU. Butadiene rubber, because it lacks side chains, has excellent wear resistance; however, its high content of unsaturated double bonds in its main chain makes it highly susceptible to ozone and other harmful substances, resulting in poor slip resistance, aging resistance, yellowing resistance, ozone cracking resistance, and mechanical properties. Isoprene rubber has good elasticity and wear resistance, but its slip resistance is average. Similar to butadiene rubber, the unsaturated double bonds in its main chain lead to poor aging resistance, yellowing resistance, and ozone cracking resistance. Solution-polymerized styrene-butadiene rubber possesses excellent dry slip resistance due to the presence of benzene rings on its side groups; however, the benzene rings also cause a decrease in wear resistance and yellowing resistance. Similarly, the unsaturated double bonds in the main chain contribute to poor aging resistance, yellowing resistance, and ozone cracking resistance. EPDM rubber has good resistance to ozone cracking, aging, and yellowing due to its low content of unsaturated double bonds in the main chain. However, its low polarity and few double bonds result in poor adhesion and mechanical properties. To improve the ozone aging resistance of rubber soles, 5-10 phr of EPDM rubber is typically added. However, the resulting soles have an adhesion strength of less than 2 kg / cm² and fail to delaminate after 48 hours of hydrolysis testing. This necessitates grinding, washing, or special treatment, increasing the manufacturing costs of sole and finished shoe assembly and hindering continuous and automated production. Methyl silicone rubber exhibits good low-temperature resistance, aging resistance, yellowing resistance, and ozone cracking resistance, but its poor mechanical properties prevent it from being used alone as an outsole for athletic shoes. MPU rubber is the only material that can be used alone as a transparent rubber sole. It has a relatively balanced performance, but its anti-slip performance is slightly insufficient, and it is expensive, costing 2 to 3 times more than butadiene rubber, isoprene rubber, EPDM rubber, styrene-butadiene rubber, etc. Therefore, brands generally use it in high-end sports shoes, and it cannot be popularized in mid-to-low-end sports shoes. Its market prospects are limited, and it cannot be promoted and used on a large scale.

[0003] In published patents or documents, such as patent 200810207699.3, which mentions a pure compounded transparent polyurethane rubber, while offering good transparency and abrasion resistance, its anti-slip performance is only average. Another example is patent 201610757721.6, which uses solution-polymerized styrene-butadiene rubber, butadiene rubber, and EPDM rubber. While the high amount of EPDM rubber improves yellowing and aging, its poor mechanical properties and adhesion inevitably lead to a significant decrease in the overall mechanical properties of the rubber sole and a high risk of delamination. Patent 201610288182.6, which uses butadiene rubber and isoprene rubber, has a high content of unsaturated double bonds in the macromolecular chains of both butadiene and isoprene rubber, resulting in poor weather resistance in the rubber soles made from them. This makes them prone to yellowing, cracking, and aging, ultimately affecting the quality of the shoes. In addition, although the combination of EPDM and MPU used in patent 201710847984.0 has good resistance to aging, yellowing, and cracking, EPDM has extremely poor anti-slip and wear resistance. When combined with MPU, it will lead to a decrease in the overall anti-slip and wear resistance of the rubber. Summary of the Invention

[0004] Based on the above-mentioned technical bottlenecks, this invention aims to develop a wet-slip and ozone-resistant transparent rubber outsole and its preparation method. The wet-slip and ozone-resistant transparent rubber outsole provided by this invention not only has excellent ozone crack resistance, slip resistance, and wear resistance, but also meets the mechanical performance indicators of rubber shoe soles, and the cost is acceptable to the market.

[0005] This invention provides a wet-slip and ozone-resistant transparent rubber outsole, prepared from raw materials comprising the following components:

[0006] 75-90 parts by weight of polyurethane in its primary form;

[0007] 10-25 parts by weight of trans-butadiene rubber;

[0008] 5-10 parts by weight of low molecular weight polyisobutylene;

[0009] 5-10 parts by weight of maleic anhydride-modified liquid polybutadiene;

[0010] 30-35 parts by weight of transparent silica;

[0011] 2-3 parts by weight of methyl vinyl silicone oil;

[0012] Paraffin oil 3-5 parts by weight;

[0013] 1-1.5 parts by weight of nano-active zinc oxide;

[0014] 1-2 parts by weight of polyethylene glycol;

[0015] Stearic acid 0.3-0.5 parts by weight;

[0016] Antioxidant 0.5–1.0 parts by weight;

[0017] Light stabilizer 0.5 to 1 part by weight;

[0018] 0-1 parts by weight of pigment;

[0019] Peroxide crosslinking agent 0.5 to 0.7 parts by weight.

[0020] Preferably, the Mooney viscosity of the primary polyurethane is 30 to 60 MU.

[0021] Preferably, in the molecular structure of the trans-butadiene rubber, the molar content of trans-1,4-butadiene in the butadiene structural unit is 70-80%, the molar content of cis-1,4-butadiene is 19-25%, and the molar content of 1,2-butadiene is 1-5%; the molar content of trans-1,4-isoprene in the isoprene structural unit is 80-92%, the molar content of cis-1,4-isoprene is 6-16%, and the molar content of 3,4-isoprene is 2-4%.

[0022] Preferably, the number average molecular weight of the low molecular weight polyisobutylene is 200 to 10,000.

[0023] Preferably, the transparent silica has a mesh size of 5000 mesh to 10000 mesh.

[0024] Preferably, the viscosity of the methyl vinyl silicone oil is 100,000 to 250,000 mPa·s.

[0025] Preferably, the specific surface area of ​​the nano-active zinc oxide is 80–120 m². 2 / g.

[0026] Preferably, the molecular weight of the polyethylene glycol is 3000 to 5000.

[0027] Preferably, the antioxidant is butylated hydroxytoluene; the light stabilizer is a transparent light stabilizer; and the peroxide crosslinking agent is 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane.

[0028] This invention also provides a method for preparing the above-described anti-slip, ozone-resistant transparent rubber outsole, comprising the following steps:

[0029] a) Pour the primary form of polyurethane, trans-butadiene rubber, low molecular weight polyisobutylene, and maleic anhydride-modified liquid polybutadiene into a mixer, start the mixer, mix for 5 to 10 minutes, and when the temperature of the mixer rises to 100°C to 120°C, pour out the mixed rubber compound.

[0030] b) Place the mixed rubber compound obtained in step a) into a two-roll mill, tumble it continuously 5 to 10 times, and produce a sheet with a thickness of 1 cm to 5 cm. Let it stand for 4 to 8 hours to obtain the mixed rubber compound after standing.

[0031] c) Pour the mixed rubber compound obtained in step b) back into the internal mixer, and add transparent silica, methyl vinyl silicone oil, paraffin oil, nano-active zinc oxide, polyethylene glycol, stearic acid, antioxidant, light stabilizer, and colorant into the internal mixer. Mix for 5 to 10 minutes. When the temperature of the internal mixer rises to 100°C to 120°C, pour out the rubber compound after the second mixing.

[0032] d) Pour the secondary mixed rubber compound obtained in step c) into a two-roll mill, tumble it continuously 5 to 8 times, add peroxide crosslinking agent, and produce a sheet with a thickness of 1 cm to 5 cm.

[0033] e) Cut the 1-5 cm thick sheet obtained in step d) into the size required by the mold, put it into the shoe sole mold, and vulcanize it for 200-300 seconds at 150-170℃ using a flat vulcanizing machine. Remove it to obtain a transparent rubber outsole that is wet-slip resistant and ozone resistant.

[0034] This invention provides a transparent rubber outsole that is wet-slip resistant and ozone-resistant, prepared from raw materials comprising the following components: 75-90 parts by weight of primary-shaped polyurethane; 10-25 parts by weight of trans-butadiene rubber; 5-10 parts by weight of low molecular weight polyisobutylene; 5-10 parts by weight of maleic anhydride-modified liquid polybutadiene; 30-35 parts by weight of transparent silica; 2-3 parts by weight of methyl vinyl silicone oil; 3-5 parts by weight of paraffin oil; 1-1.5 parts by weight of nano-active zinc oxide; 1-2 parts by weight of polyethylene glycol; 0.3-0.5 parts by weight of stearic acid; 0.5-1.0 parts by weight of antioxidant; 0.5-1 parts by weight of light stabilizer; 0-1 parts by weight of pigment; and 0.5-0.7 parts by weight of peroxide crosslinking agent. Compared with the prior art, the anti-slip and ozone-resistant transparent rubber outsole provided by the present invention uses specific components in specific amounts to achieve better overall interaction. The resulting anti-slip and ozone-resistant transparent rubber outsole not only has excellent ozone crack resistance, slip resistance, and wear resistance, but also meets the mechanical performance indicators of rubber shoe soles, and the cost is acceptable to the market.

[0035] In addition, the preparation method provided by this invention is simple in process and easy to control in conditions, making it suitable for large-scale production and with broad application prospects. Detailed Implementation

[0036] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] This invention provides a wet-slip and ozone-resistant transparent rubber outsole, prepared from raw materials comprising the following components:

[0038] 75-90 parts by weight of polyurethane in its primary form;

[0039] 10-25 parts by weight of trans-butadiene rubber;

[0040] 5-10 parts by weight of low molecular weight polyisobutylene;

[0041] 5-10 parts by weight of maleic anhydride-modified liquid polybutadiene;

[0042] 30-35 parts by weight of transparent silica;

[0043] 2-3 parts by weight of methyl vinyl silicone oil;

[0044] Paraffin oil 3-5 parts by weight;

[0045] 1-1.5 parts by weight of nano-active zinc oxide;

[0046] 1-2 parts by weight of polyethylene glycol;

[0047] Stearic acid 0.3-0.5 parts by weight;

[0048] Antioxidant 0.5–1.0 parts by weight;

[0049] Light stabilizer 0.5 to 1 part by weight;

[0050] 0-1 parts by weight of pigment;

[0051] Peroxide crosslinking agent 0.5 to 0.7 parts by weight.

[0052] In this invention, the anti-slip and ozone-resistant transparent rubber outsole is prepared from raw materials including primary-shaped polyurethane, trans-butylene rubber, low molecular weight polyisobutylene, maleic anhydride-modified liquid polybutadiene, transparent silica, methyl vinyl silicone oil, paraffin oil, nano-activated zinc oxide, polyethylene glycol, stearic acid, antioxidants, light stabilizers, pigments, and peroxide crosslinking agents. Preferably, it is prepared from primary-shaped polyurethane, trans-butylene rubber, low molecular weight polyisobutylene, maleic anhydride-modified liquid polybutadiene, transparent silica, methyl vinyl silicone oil, paraffin oil, nano-activated zinc oxide, polyethylene glycol, stearic acid, antioxidants, light stabilizers, pigments, and peroxide crosslinking agents. This invention does not impose any special restrictions on the source of the above-mentioned raw materials; commercially available products well-known to those skilled in the art can be used.

[0053] In this invention, the Mooney viscosity (ML1+4@100℃) of the primary polyurethane is preferably 30-60 MU, more preferably 45-55 MU; the preferred variety is T19760.

[0054] Polyether-type primary polyurethane has the characteristics of high transparency (light transmittance greater than 90%), strong polarity, good adhesion, and good wear resistance and slip resistance. Adding primary polyurethane can improve the polarity of trans-butadiene rubber soles, thereby improving the adhesion of the soles.

[0055] In this invention, the trans-butadiene-pentadiene rubber is a block copolymer synthesized from butadiene and isoprene, and its molecular structure mainly consists of trans-butadiene and trans-isoprene. In the molecular structure of the trans-butadiene-pentadiene rubber, the molar content of trans-1,4-butadiene in the butadiene structural unit is preferably 70-80%, more preferably 75%, the molar content of cis-1,4-butadiene is preferably 19-25%, more preferably 21%, and the molar content of 1,2-butadiene is preferably 1-5%, more preferably 4%. In the isoprene structural unit, the molar content of trans-1,4-isoprene is preferably 80-92%, more preferably 85%, the molar content of cis-1,4-isoprene is preferably 6-16%, more preferably 12%, and the molar content of 3,4-isoprene is preferably 2-4%, more preferably 3%. The preferred variety is TBIR 2249.

[0056] As a multi-block copolymer, TBIR's trans-isoprene macromolecular backbone structure suffers from reduced crystallinity due to the introduction of trans-1,4-polybutadiene (TPB) structural units. This leads to a decrease in the regularity of the isoprene macromolecular backbone structure, but not a complete loss of crystallinity. Therefore, TBIR is a rubber material with certain crystallinity. Crystalline TBIR plays a crucial role in reinforcing conventional amorphous rubber materials. The numerous amorphous regions of TBIR ensure sufficient anti-slip properties, elasticity, and low-temperature resistance, while the crystalline regions have a positive impact on the properties of vulcanizates. They can improve the physical and mechanical properties of blended vulcanizates, enhance their abrasion resistance and flexural fatigue resistance, and reduce compression set, which is highly beneficial for designing high-performance shoe soles.

[0057] In this invention, the number average molecular weight of the low molecular weight polyisobutylene is preferably 200 to 10,000, more preferably 350 to 3,500; the preferred variety is PB2400.

[0058] Polyisobutylene (PIB) is a colorless, odorless, and non-toxic viscous or semi-solid polymer. PIB can be classified into low molecular weight PIB, medium molecular weight PIB, and high molecular weight PIB according to its molecular weight. Generally, PIB with a molecular weight between 350 and 3500 is called low molecular weight PIB. Due to its excellent adhesion, low molecular weight PIB is an excellent tackifier and is often used to produce wrapping films such as cling film. These films have a certain degree of viscoelasticity and tensile strength, which allows them to wrap and protect goods. Considering PIB's excellent and lasting adhesion, good compatibility with many resins, and non-toxic and harmless applications, it is used in rubber shoe soles to improve their dry grip performance.

[0059] In this invention, the maleic anhydride-modified liquid polybutadiene is preferably maleic anhydride-modified liquid polybutadiene, with Polyvest MA-75 being a preferred variety.

[0060] Polyurethane rubber contains many repeating urethane segments in its polymer backbone, and its molecular structure has very few double bonds. Trans-butadiene rubber is a low-polarity material. Therefore, these two types of materials have poor compatibility. Maleic anhydride-modified liquid polybutadiene is a stereooriented, low-viscosity, hydroxyl-terminated liquid polybutadiene with a high content of double bonds and α-W-terminated hydroxyl functional groups. These groups are randomly distributed on the polymer backbone, which can polarize the non-polar polybutadiene, thereby giving it high reactivity and crosslinking density. This can effectively improve the compatibility between polyurethane and trans-butadiene rubber.

[0061] In this invention, the mesh size of the transparent silica is preferably 5000 mesh to 10000 mesh, more preferably 5000 mesh to 6000 mesh; the preferred variety is LM150.

[0062] Although the refractive index of silica differs significantly from that of rubber, the small particle size of transparent silica allows light to diffract, resulting in good transparency in rubber products. This invention uses highly dispersed transparent silica of 5000-10000 mesh, which not only fills and improves the physical and processing properties of the rubber compound, but also enhances the abrasion resistance, hardness, tensile strength, and tear strength of the shoe sole, while maintaining high transparency of the rubber.

[0063] In this invention, the methyl vinyl silicone oil includes medium molecular weight vinyl silicone oil, wherein it is a methyl vinyl polysiloxane with vinyl groups in the middle of the molecular chain; the viscosity of the methyl vinyl silicone oil is preferably 100,000 to 250,000 mPa·s; the preferred variety is TNVF-200M.

[0064] This invention introduces a crosslinkable vinyl silicone oil abrasion-resistant agent with double bonds. On the one hand, the Si-O structure in the silicone oil achieves abrasion resistance, while peroxide free radicals can abstract hydrogen atoms from the vinyl groups, thereby increasing the degree and speed of crosslinking of the vinyl silicone oil, which is beneficial to improving the abrasion resistance of rubber shoe soles. On the other hand, methyl vinyl silicone oil can act as a coupling agent between silica and the rubber matrix, reducing the hydrophilicity of the silica surface and improving the bonding ability between rubber and silica, thereby improving the strength and hardness of the rubber.

[0065] In this invention, the paraffin oil preferably includes grades that are transparent and colorless with a viscosity of <40 at 40°C, with 150N being a preferred grade.

[0066] In this invention, the specific surface area (BET) of the nano-active zinc oxide is preferably 80–120 m². 2 / g, more preferably 95-105m 2 / g; preferably, the grade with an effective ingredient zinc oxide content >99%, among which the preferred variety is ZnO 997.

[0067] In this invention, the molecular weight of the polyethylene glycol is preferably 3000-5000, more preferably 3600-4400; a preferred variety is PEG4000.

[0068] In this invention, the antioxidant is preferably butylated hydroxytoluene (BHT); the preferred variety is butylated hydroxytoluene (BHT).

[0069] In this invention, the light stabilizer is preferably a transparent light stabilizer; the preferred variety is PR-25.

[0070] In this invention, the peroxide crosslinking agent is preferably 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane; the preferred variety is Luperox231.

[0071] This invention provides a transparent rubber outsole that is wet-slip and ozone-resistant. It is produced by organically combining trans-butadiene rubber, primary-shaped polyurethane, low-molecular-weight polyisobutylene, methyl vinyl silicone oil, transparent silica, and maleic anhydride-modified liquid polybutadiene, resulting in an outsole with a hardness of 63±3A, ozone resistance ≥4, dry slip resistance ≥1.3, wet slip resistance ≥0.8, and DIN abrasion resistance ≤70mm. 3 The product features a semi-transparent rubber outsole with a tensile strength ≥20MPa and a right-angle tear strength ≥35N / cm. It boasts excellent ozone resistance and superior slip resistance, overcoming the technical bottlenecks of existing transparent rubbers being unresistant to ozone and compounded polyurethane rubbers being costly and lacking sufficient slip resistance. It also possesses good wear resistance and mechanical properties, making it a promising product with significant market potential.

[0072] This invention also provides a method for preparing the above-described anti-slip, ozone-resistant transparent rubber outsole, comprising the following steps:

[0073] a) Pour the primary form of polyurethane, trans-butadiene rubber, low molecular weight polyisobutylene, and maleic anhydride-modified liquid polybutadiene into a mixer, start the mixer, mix for 5 to 10 minutes, and when the temperature of the mixer rises to 100°C to 120°C, pour out the mixed rubber compound.

[0074] b) Place the mixed rubber compound obtained in step a) into a two-roll mill, tumble it continuously 5 to 10 times, and produce a sheet with a thickness of 1 cm to 5 cm. Let it stand for 4 to 8 hours to obtain the mixed rubber compound after standing.

[0075] c) Pour the mixed rubber compound obtained in step b) back into the internal mixer, and add transparent silica, methyl vinyl silicone oil, paraffin oil, nano-active zinc oxide, polyethylene glycol, stearic acid, antioxidant, light stabilizer, and colorant into the internal mixer. Mix for 5 to 10 minutes. When the temperature of the internal mixer rises to 100°C to 120°C, pour out the rubber compound after the second mixing.

[0076] d) Pour the secondary mixed rubber compound obtained in step c) into a two-roll mill, tumble it continuously 5 to 8 times, add peroxide crosslinking agent, and produce a sheet with a thickness of 1 cm to 5 cm.

[0077] e) Cut the 1-5 cm thick sheet obtained in step d) into the size required by the mold, put it into the shoe sole mold, and vulcanize it for 200-300 seconds at 150-170℃ using a flat vulcanizing machine. Remove it to obtain a transparent rubber outsole that is wet-slip resistant and ozone resistant.

[0078] The preparation method provided by this invention mainly includes: first mixing, first sheeting, second mixing, second sheeting, and vulcanization; preferably:

[0079] a) Pour the primary form of polyurethane, trans-butadiene rubber, low molecular weight polyisobutylene, and maleic anhydride-modified liquid polybutadiene (base rubber, rubber compatibilizer, and low molecular weight polyisobutylene) into a mixer, start the mixer, and mix for 8 minutes to ensure that the rubber and compatibilizer are fully mixed. When the temperature of the mixer rises to 110°C, pour out the mixed rubber compound.

[0080] b) Place the mixed rubber compound obtained in step a) into a two-roll mill, tumble it continuously 5 to 10 times, and produce a sheet with a thickness of 2 cm. Let it stand for 4 to 8 hours to obtain the mixed rubber compound after standing.

[0081] c) Pour the mixed rubber compound obtained in step b) back into the internal mixer, and add transparent silica, methyl vinyl silicone oil, paraffin oil, nano active zinc oxide, polyethylene glycol, stearic acid, antioxidant, light stabilizer, and color powder into the internal mixer. Mix for 8 minutes. When the temperature of the internal mixer rises to 110°C, pour out the rubber compound after the second mixing.

[0082] d) Pour the secondary mixed rubber compound obtained in step c) into a two-roll mill, tumble it continuously 5 to 8 times, add peroxide crosslinking agent, and produce a 2 cm thick sheet.

[0083] e) Cut the 1-5 cm thick sheet obtained in step d) into the size required by the mold, put it into the shoe sole mold, and vulcanize it at 160°C for 250 seconds using a flat vulcanizing machine. Remove it to obtain a transparent rubber outsole that is wet-slip resistant and ozone resistant.

[0084] The preparation method provided by this invention is simple in process and easy to control under certain conditions, making it suitable for large-scale production and with broad application prospects.

[0085] Compared with existing sports shoe rubber outsoles, this invention introduces trans-butadiene rubber (TBIR) with excellent properties into transparent rubber for the first time. The numerous amorphous regions in TBIR molecules have excellent anti-slip properties, while the crystalline regions in TBIR molecules can improve the wear resistance and mechanical properties of the rubber. Ultimately, this improves the anti-slip and wear resistance of the polyurethane rubber and TBIR blend, while simultaneously reducing material costs.

[0086] Compared with existing transparent rubber outsoles for athletic shoes, this invention is the first to improve the dry slip performance of the sole by introducing low molecular weight polyisobutylene with excellent adhesion. Combined with trans-butadiene rubber (TBIR), it results in a rubber sole with excellent dry and wet slip performance.

[0087] To achieve compatibility between polar polyurethane rubber and non-polar trans-butyl pentadiene rubber, this invention adds maleic anhydride-modified liquid polybutadiene compatibilizer. The polybutadiene structure is similar to and compatible with trans-butyl pentadiene rubber. Maleic anhydride modification causes α-W-terminated hydroxyl functional groups to be randomly distributed on the polybutadiene backbone. These hydroxyl functional groups can connect with the urethane segments in the polyurethane rubber. Through chemical bonding and similar physical interactions, the polyurethane rubber, trans-butyl pentadiene rubber, and maleic anhydride-modified liquid polybutadiene are tightly bonded together, significantly improving the compatibility between the two.

[0088] Compared with existing rubber shoe soles that use ordinary silane coupling agents, this invention introduces methyl vinyl silicone oil, which not only plays a coupling role in the silica and rubber matrix like silane coupling agents, improving the bonding ability between the two; at the same time, the presence of vinyl can improve the overall crosslinking degree and crosslinking speed of the rubber matrix, which is beneficial to improving the wear resistance of the rubber shoe sole, which is something that silane coupling agents do not have.

[0089] This invention provides a transparent rubber outsole that is wet-slip resistant and ozone-resistant, prepared from raw materials comprising the following components: 75-90 parts by weight of primary-shaped polyurethane; 10-25 parts by weight of trans-butadiene rubber; 5-10 parts by weight of low molecular weight polyisobutylene; 5-10 parts by weight of maleic anhydride-modified liquid polybutadiene; 30-35 parts by weight of transparent silica; 2-3 parts by weight of methyl vinyl silicone oil; 3-5 parts by weight of paraffin oil; 1-1.5 parts by weight of nano-active zinc oxide; 1-2 parts by weight of polyethylene glycol; 0.3-0.5 parts by weight of stearic acid; 0.5-1.0 parts by weight of antioxidant; 0.5-1 parts by weight of light stabilizer; 0-1 parts by weight of pigment; and 0.5-0.7 parts by weight of peroxide crosslinking agent. Compared with the prior art, the anti-slip and ozone-resistant transparent rubber outsole provided by the present invention uses specific components in specific amounts to achieve better overall interaction. The resulting anti-slip and ozone-resistant transparent rubber outsole not only has excellent ozone crack resistance, slip resistance, and wear resistance, but also meets the mechanical performance indicators of rubber shoe soles, and the cost is acceptable to the market.

[0090] In addition, the preparation method provided by this invention is simple in process and easy to control in conditions, making it suitable for large-scale production and with broad application prospects.

[0091] To further illustrate the present invention, the following embodiments are provided for detailed description. All raw materials used in the following embodiments of the present invention are commercially available.

[0092] Examples and Comparative Examples

[0093] The formula composition is shown in Tables 1 and 2 below.

[0094] Table 1. Rubber outsole material formulations for comparative examples.

[0095]

[0096]

[0097] Table 2. Rubber outsole material formulations from the examples.

[0098]

[0099] In the table:

[0100] Primary form polyurethane T19760: Mooney viscosity 50±5 (ML1+4@100℃), Guangdong Shouli Company.

[0101] Trans-butadiene rubber TBIR 2249: Mooney viscosity 49±5 (ML1+4@100℃), Shandong Jingbo Petrochemical Co., Ltd.

[0102] Polyisobutylene PB2400: Number average molecular weight 2450, viscosity at 100℃ 4700±200 (cst), Daelim Corporation, South Korea.

[0103] Maleic anhydride-modified liquid polybutadiene Polyvest MA-75: molecular weight 3000, viscosity at 40℃ 6000~9000 (cst), Evonik Degussa.

[0104] Transparent silica LM150: 6000 mesh, Cabot Corporation.

[0105] Methyl vinyl silicone oil TNVF-200M: viscosity 200,000 (mpa.s), Dongguan Tianan Silicone Rubber Technology Co., Ltd.

[0106] Paraffin oil 150N: Shandong Zhuyou Lubrication Technology Co., Ltd.

[0107] ZnO 997: Specific surface area 100±5m² 2 / g brand, Tai-Hsiang Company.

[0108] Polyethylene glycol PEG 4000: molecular weight 3600-4400, Haian Petrochemical Plant, Jiangsu Province.

[0109] Light stabilizer PR-25: [(4-methoxyphenyl)methylene]dimethyl ester, Clariant.

[0110] Stearic acid: Dukuda Indonesia.

[0111] Antioxidant BHT: Zhengzhou Dexin Chemical Industry Co., Ltd.

[0112] Crosslinking agent Luperox 231: Arkema.

[0113] Pigment: Blue, Ching Feng Company, Taiwan, China.

[0114] SSBR 303: Mooney viscosity 45 (ML1+4@100℃), Asahi Kasei, Japan.

[0115] BR1208: Mooney viscosity 45 (ML1+4@100℃), LG Corporation, South Korea.

[0116] IR0307: Mooney viscosity 50 (ML1+4@100℃), Kraton Pharmaceuticals, USA.

[0117] EPDM 5565: Mooney viscosity 65 (ML1+4@100℃), Dow Chemical Company.

[0118] M97: Mooney viscosity 45±10 (ML1+4@100℃), Guangdong Shunli Company.

[0119] Silane coupling agent A-172: colorless and transparent liquid, Guangdong Shouli Company.

[0120] The specific preparation method is as follows:

[0121] Mixing 1: Pour the base rubber, rubber compatibilizer, and low molecular weight polyisobutylene into the internal mixer, start the internal mixer, and mix for 8 minutes to fully mix the rubber and compatibilizer. When the temperature of the internal mixer rises to 110°C, pour out the mixed rubber compound.

[0122] Sheeting 1: Place the mixed rubber compound into a two-roll mill, tumble it continuously 5 to 10 times, and produce a sheet with a thickness of 2 cm. Let it stand for 4 to 8 hours before use.

[0123] Mixing 2: After the mixed rubber compound has been left to stand for 4-8 hours, pour it back into the internal mixer. Add the transparent silica, methyl vinyl silicone oil, paraffin oil, nano-active zinc oxide, polyethylene glycol, stearic acid, antioxidants, light stabilizers, colorants and other compounding agents into the internal mixer. Mix for 8 minutes. When the temperature of the internal mixer reaches 110°C, pour out the mixed rubber compound.

[0124] Sheet 2: Pour the mixed rubber compound into the open mill, tumble it continuously 5 to 8 times, add peroxide crosslinking agent, and produce a 2 cm thick sheet.

[0125] Vulcanization: Cut a 2cm thick sheet into the size required by the mold, place it into the shoe sole mold, and vulcanize it for 250 seconds at 160℃ using a flat vulcanizing machine. Remove the vulcanized rubber sole to obtain the product.

[0126] The performance of the products obtained from each embodiment and comparative example was tested, and the results are shown in Tables 3 and 4 below.

[0127] Table 3. Physical property data of the rubber outsole materials of the comparative examples.

[0128]

[0129] Table 4. Physical property data of the rubber outsole material in the examples.

[0130]

[0131]

[0132] Experimental results show that:

[0133] (1) The test data of Comparative Examples 1 and 3 show that if transparent rubber is prepared by using butadiene rubber and isoprene rubber or butadiene rubber and solution-polymerized styrene-butadiene rubber, although butadiene rubber has excellent wear resistance, it has extremely poor anti-slip properties. Moreover, butadiene rubber, isoprene rubber and styrene-butadiene rubber contain a large number of double bonds in their molecular structure, so their aging resistance, yellowing resistance and ozone resistance are not ideal and cannot meet the basic requirements of rubber shoe soles.

[0134] (2) The test data from Comparative Example 2 show that: using solution-polymerized styrene-butadiene rubber to improve the anti-slip properties of butadiene rubber and adding a small amount of EPDM rubber to improve ozone resistance, the anti-slip properties, aging resistance, yellowing resistance and ozone resistance of the final product are improved, but the wear resistance and mechanical properties will decrease; moreover, the ozone resistance, aging resistance and yellowing resistance are still not ideal.

[0135] (3) The test data from Comparative Examples 4 and 5 show that if MPU (polyurethane mixed rubber) is used alone to prepare rubber shoe soles, although the wear resistance, mechanical properties, aging resistance, yellowing resistance, and ozone resistance are relatively balanced, the material cost of MPU is more than twice that of ordinary rubber, and the anti-slip performance is insufficient. If a small amount of EPDM rubber, which is also ozone resistant, is added to the MPU matrix rubber, the cost can be reduced by about 10%, but the poor mechanical properties of EPDM rubber lead to a decrease in the wear resistance, anti-slip performance, and mechanical properties of the MPU+EPDM rubber shoe sole.

[0136] (4) The test data from Examples 1 to 7 show that different combinations of polyurethane (75-90 parts by weight), trans-butadiene rubber (10-25 parts by weight), low molecular weight polyisobutylene (5-10 parts by weight), maleic anhydride-modified liquid polybutadiene (5-10 parts by weight), transparent silica (30-35 parts by weight), and methyl vinyl silicone oil (2-3 parts by weight) can all achieve a hardness of 63±3A, ozone resistance ≥4, dry slip resistance ≥1.3, wet slip resistance ≥0.8, and DIN abrasion resistance ≤70mm. 3 Rubber outsole with tensile strength ≥20MPa and right-angle tear strength ≥35N / cm.

[0137] (5) Comparison of the test data of Comparative Example 6 and Example 1 shows that without the addition of maleic anhydride liquid polybutadiene compatibilizer, the polar polyurethane rubber and the non-polar trans-butadiene rubber have poor compatibility, which greatly affects the tensile strength and tear strength of the rubber shoe sole; at the same time, the anti-slip performance and wear resistance also decrease.

[0138] (6) Comparison of the test data of Comparative Example 7 and Example 1 shows that the anti-slip performance of rubber shoe soles is improved after adding low molecular weight polyisobutylene. The improvement is greater when the amount added is 10 parts than when it is 5 parts. Moreover, the adverse effects of low molecular weight polyisobutylene on other properties are minimal.

[0139] (7) Comparison of the test data of Comparative Example 8 and Example 1 shows that adding methyl vinyl silicone oil is more effective than adding silicone oil coupling agent, and the wear resistance, slip resistance, tensile strength and tear strength of the final rubber shoe sole are improved to a certain extent.

[0140] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A transparent rubber outsole that is wet-slip resistant and ozone-resistant, characterized in that, It is prepared from raw materials including the following components: 75-90 parts by weight of polyurethane in its primary form; 10-25 parts by weight of trans-butadiene rubber; 5-10 parts by weight of low molecular weight polyisobutylene; 5-10 parts by weight of maleic anhydride-modified liquid polybutadiene; 30-35 parts by weight of transparent silica; 2-3 parts by weight of methyl vinyl silicone oil; Paraffin oil 3-5 parts by weight; 1-1.5 parts by weight of nano-active zinc oxide; 1-2 parts by weight of polyethylene glycol; Stearic acid 0.3-0.5 parts by weight; Antioxidant 0.5–1.0 parts by weight; Light stabilizer 0.5 to 1 part by weight; 0-1 parts by weight of pigment; Peroxide crosslinking agent 0.5 to 0.7 parts by weight.

2. The anti-slip, ozone-resistant transparent rubber outsole according to claim 1, characterized in that, The Mooney viscosity of the primary form of polyurethane is 30–60 MU.

3. The anti-slip, ozone-resistant transparent rubber outsole according to claim 1, characterized in that, In the molecular structure of the trans-butadiene rubber, the molar content of trans-1,4-butadiene in the butadiene structural unit is 70-80%, the molar content of cis-1,4-butadiene is 19-25%, and the molar content of 1,2-butadiene is 1-5%; in the isoprene structural unit, the molar content of trans-1,4-isoprene is 80-92%, the molar content of cis-1,4-isoprene is 6-16%, and the molar content of 3,4-isoprene is 2-4%.

4. The anti-slip, ozone-resistant transparent rubber outsole according to claim 1, characterized in that, The number average molecular weight of the low molecular weight polyisobutylene is 200 to 10,000.

5. The anti-slip, ozone-resistant transparent rubber outsole according to claim 1, characterized in that, The transparent silica has a mesh size of 5000 to 10000 mesh.

6. The anti-slip, ozone-resistant transparent rubber outsole according to claim 1, characterized in that, The viscosity of the methyl vinyl silicone oil is 100,000 to 250,000 mPa·s.

7. The anti-slip, ozone-resistant transparent rubber outsole according to claim 1, characterized in that, The specific surface area of ​​the nano-active zinc oxide is 80–120 m². 2 / g.

8. The anti-slip, ozone-resistant transparent rubber outsole according to claim 1, characterized in that, The molecular weight of the polyethylene glycol is 3000-5000.

9. The anti-slip, ozone-resistant transparent rubber outsole according to claim 1, characterized in that, The antioxidant is butylated hydroxytoluene; the light stabilizer is a transparent light stabilizer; and the peroxide crosslinking agent is 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane.

10. A method for preparing a wet-slip, ozone-resistant transparent rubber outsole according to any one of claims 1 to 9, characterized in that, Includes the following steps: a) Pour the primary form of polyurethane, trans-butadiene rubber, low molecular weight polyisobutylene, and maleic anhydride-modified liquid polybutadiene into a mixer, start the mixer, mix for 5 to 10 minutes, and when the temperature of the mixer rises to 100°C to 120°C, pour out the mixed rubber compound. b) Place the mixed rubber compound obtained in step a) into a two-roll mill, tumble it continuously 5 to 10 times, and produce a sheet with a thickness of 1 cm to 5 cm. Let it stand for 4 to 8 hours to obtain the mixed rubber compound after standing. c) Pour the mixed rubber compound obtained in step b) back into the internal mixer, and add transparent silica, methyl vinyl silicone oil, paraffin oil, nano-active zinc oxide, polyethylene glycol, stearic acid, antioxidant, light stabilizer, and colorant into the internal mixer. Mix for 5 to 10 minutes. When the temperature of the internal mixer rises to 100°C to 120°C, pour out the rubber compound after the second mixing. d) Pour the secondary mixed rubber compound obtained in step c) into a two-roll mill, tumble it continuously 5 to 8 times, add peroxide crosslinking agent, and produce a sheet with a thickness of 1 cm to 5 cm. e) Cut the 1-5 cm thick sheet obtained in step d) into the size required by the mold, put it into the shoe sole mold, and vulcanize it for 200-300 seconds at 150-170℃ using a flat vulcanizing machine. Remove it to obtain a transparent rubber outsole that is wet-slip resistant and ozone resistant.

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