Anti-aging rubber material for boots and preparation method thereof

Abstract

The invention relates to the field of rubber products, and particularly discloses an anti-aging rubber material for boots and a preparation method of the anti-aging rubber material. The anti-aging sole material comprises the following raw materials in parts by weight: 70-80 parts of silicone rubber, 20-30 parts of ethylene propylene diene monomer, 8-10 parts of low-density polyethylene, 5-8 parts of ethylene-octylene copolymer, 3-4 parts of compatilizer, 1-1.2 parts of vulcanizing agent, 30-37 parts of filler, 0.5-3 parts of accelerant, 18-20 parts of AC foaming agent, 1-3 parts of lubricant, 1-2 parts of anti-aging agent and 0.25-0.5 part of flame retardant. The anti-aging agent comprises POSS (Polyhedral Oligomeric Silsesquioxane) grafted aramid fibers and ionic liquid modified carbon nanotubes in a mass ratio of (1-1.5): 1. The rubber material disclosed by the invention has the advantages of high aging resistance and good compressive deformation resistance.

Description

Technical Field

[0001] The present application relates to the technical field of rubber products, and more specifically, to an aging-resistant rubber material for boots and a preparation method thereof. Background Art

[0002] Boots are shoes with a tube-shaped upper that is higher than the ankle. In winter, boots are the first choice for many people to keep warm due to their good thermal insulation performance. The soles of boots are generally made of natural rubber, which is a widely used natural polymer compound. 90% to 95% of the ingredients are cis-1,4-polyisoprene, with a molecular weight of 3×10 5 g / mol, and the remaining components are non-rubber materials such as sugars, ash, fatty acids and proteins. Natural rubber is the general-purpose rubber with the best comprehensive performance. Its vulcanized rubber has high elasticity, good processing performance, cold resistance and wear resistance.

[0003] With the continuous development of sole materials, comfort and lightness have become an important criterion for people to choose shoes and boots. Therefore, high elasticity and lightness have become the main direction of the current development of sole materials. Rubber, as a traditional sole material, has good wear resistance and anti-slip properties, and has environmental adaptability such as high and low temperature resistance, but the specific gravity of rubber is 1.0-1.4g / cm 3 , which makes the shoes very bulky to wear.

[0004] In the prior art, a Chinese invention patent with application number CN2011101493360 discloses a foamed rubber sole and a preparation method thereof. The weight percentage of the foamed rubber sole formula is: 40% to 60% natural rubber, 0.5% to 1.5% sulfur, 1% to 3% zinc oxide, 20% to 40% silicon dioxide, 1% to 3% recycled rubber powder, 1% to 3% stearic acid, 0.5% to 3% vulcanization accelerator, 10% to 20% engine oil, 0.1% to 0.5% toner, and 4% to 10% foaming agent. The foamed rubber sole is light in weight, good in vibration reduction performance, high in comfort, and has wear resistance and water resistance. However, in view of the above-mentioned related technologies, the inventors found that natural rubber contains unsaturated double bonds, has weak resistance to light, heat, ozone, radiation, etc., and has relatively poor aging resistance. When exposed to the external environment for a long time, the sole is prone to stickiness, hardening, and even cracking, which affects the wearing life of the sole. Summary of the invention

[0005] In order to improve the anti-aging ability of the foamed sole material, the present application provides an anti-aging sole material for boots and a preparation method thereof.

[0006] In a first aspect, the present application provides an anti-aging sole material for boots, which adopts the following technical solution: An anti-aging sole material for boots, comprising the following raw materials in parts by weight: 70-80 parts of silicone rubber, 20-30 parts of EPDM rubber, 8-10 parts of low-density polyethylene, 5-8 parts of ethylene-octene copolymer, 3-4 parts of compatibilizer, 1-1.2 parts of vulcanizer, 30-37 parts of filler, 0.5-3 parts of accelerator, 18-20 parts of AC foaming agent, 1-3 parts of lubricant, 1-2 parts of antioxidant, and 0.25-0.5 parts of flame retardant; The antioxidant comprises POSS grafted aramid fiber and ionic liquid modified carbon nanotube in a mass ratio of 1-1.5:1.

[0007] By adopting the above technical scheme, silicone rubber is used as the main material, and EPDM rubber, low-density polyethylene and ethylene-octene copolymer are added. The low-density polyethylene has good mechanical properties and can play an accelerating role when blended with silicone rubber, thereby improving the melt strength and ensuring the stable growth of the bubbles. During reciprocating compression, the partial crystallization areas produced by the low-density polyethylene can be used as physical cross-linking points inside the material, while the arrangement of the silicone rubber molecular chains will be more orderly, thereby reducing the internal shape entropy of the material. When the external force is removed, the compressed foamed silicone rubber recovers its deformation under the action of the entropy driving force, so that it has good elasticity and strong shape recovery ability. Ethylene-octene copolymer is a POE thermoplastic elastomer with excellent aging resistance, such as ozone resistance, heat resistance, and weather resistance. Its structural unit is octene, with a large number of side carbon atoms, good molecular chain flexibility, and high molecular chain entanglement density with silicone rubber. The molecular chain moves faster during heating and preferentially disentangles, so it can improve the heat resistance of foamed silicone rubber, maintain stable performance in high temperature environments, and help delay the aging process of silicone rubber at high temperatures. It can also enhance the tensile strength and other mechanical properties of foamed silicone rubber, which helps silicone rubber maintain good mechanical properties during thermal aging. Blending EPDM rubber with silicone rubber for foaming can improve processing convenience, make foaming smoother, and improve production efficiency. At the same time, it enhances the heat resistance of foamed silicone rubber and increases elastic deformation.

[0008] There is a cation-π bond between the ionic liquid and the carbon nanotube, which can improve the dispersion of the carbon nanotube in the silicone rubber matrix and improve the compatibility of the carbon nanotube and the silicone rubber matrix. The double bonds in the ionic liquid are used to participate in the thermal cross-linking reaction of the silicone rubber, so that the ionic liquid is more inclined to disperse in the silicone rubber phase, thereby inducing the migration of the carbon nanotube phase to the silicone rubber phase, so that it builds a dense network in the silicone rubber phase, and enhances the interfacial force between the carbon nanotube and the silicone rubber phase, improves the tensile strength and thermal conductivity of the silicone rubber, and helps the foamed silicone rubber to maintain good mechanical properties during the thermal aging process, while better dissipating heat, slowing down the aging rate, delaying the side methyl oxidation of the foamed silicone rubber in the early stage of degradation, and improving its thermal stability; POSS is a polyhedral cage-type sesquiterpene polyhedron. Siloxane is an organic / inorganic hybrid material of a molecular machine. It has a hexahedral inorganic framework core of Si-O-Si nanostructure and is surrounded by organic groups. Its three-dimensional size is about 1-3nm, with nanometer size effect and good thermal stability. Aramid fiber has ultra-high strength and high modulus, and is resistant to high temperature, acid and alkali, and has low density. It is grafted with POSS to improve the dispersibility of aramid fiber. The aramid fiber is evenly dispersed in the foamed silicone rubber to provide mechanical strength support for the pores of the foamed silicone rubber, which is beneficial to reduce the compression deformation of the pores and enhance the tensile and tear resistance, thereby improving the overall mechanical properties of silicone rubber. In addition, the addition of aramid fiber can also reduce the penetration of aging factors such as oxygen and improve the anti-aging ability.

[0009] Optionally, the POSS grafted aramid fiber is made by the following method: The aramid fiber is immersed in a phosphoric acid solution, filtered, washed and dried to obtain the carboxylated aramid fiber; The carboxylated aramid fiber is dispersed in tetrahydrofuran, N,N'-carbonyldiimidazole is added, and the mixture is activated at 60-70°C. A tetrahydrofuran solution of amino cage silsesquioxane is added while nitrogen is introduced, and the mixture is kept warm for 10-12 hours, filtered, and dried. The mass ratio of the carboxylated aramid fiber, N,N'-carbonyldiimidazole, and amino cage silsesquioxane is 1:0.3-0.5:1-1.2.

[0010] By adopting the above technical scheme, the aramid fiber is first impregnated with a phosphoric acid solution. Under the action of phosphoric acid, the amide bonds on the surface of the aramid fiber will be hydrolyzed and broken to form functional groups with carboxyl groups, thereby obtaining carboxylated aramid fiber, which can improve the interfacial bonding force between the aramid fiber and the silicone rubber, help the fiber to better play a reinforcing role, and can also hinder the penetration of aging factors such as oxygen into the silicone rubber to a certain extent, thereby reducing the aging rate of the rubber; the carboxylated aramid fiber is mixed and activated with N,N'-carbonyldiimidazole, the carboxyl group can react with N,N'-carbonyldiimidazole, and then amino-cage silsesquioxane is grafted to construct a POSS particle modification layer on the surface of the aramid fiber to form a hybrid structure. When the aramid fiber is subjected to stress, the silicone rubber matrix and the POSS grafted aramid fiber are relatively displaced. The rough surface hinders the movement of the matrix chain segments. At the same time, after POSS modification, the interaction area between the aramid fiber and the matrix is ​​increased, the probability of interaction is increased, and the stress transfer is more effective; the grafting of POSS improves the dispersion of the aramid fiber in the silicone rubber matrix, improves its dispersibility, and improves the mechanical strength of the foamed silicone rubber. POSS has a three-dimensional cage-type inorganic framework as its core and has excellent thermal stability. At high temperatures, the alkyl bonds on the POSS are mainly decomposed, and the Si-O-Si bonds in its inorganic core will only break at higher temperatures. The decomposition of the organic part of the POSS itself will consume part of the heat, slowing down the aging rate. During the aging process, it decomposes into silica to form a deposition, forming a protective layer on the surface of the aramid fiber, which slows down heat transfer to a certain extent and inhibits the occurrence of aging.

[0011] Optionally, the aramid fiber is pretreated as follows before being immersed in the phosphoric acid solution: The aramid fiber was treated with oxygen plasma, then dispersed in deionized water, hydrotalcite and cinnamic acid were added, ultrasonically treated, vacuum pumped at 0.05-0.08 MPa for 10-12 h, and dried. The mass ratio of aramid fiber, hydrotalcite, cinnamic acid and deionized water was 15:0.1-0.2:0.1-0.2:100.

[0012] By adopting the above technical scheme, during the process of aramid fiber being treated with oxygen plasma, a large number of electrons are accelerated and bombarded onto the surface of aramid fiber. Since the electrons have a small mass and a fast speed, they can quickly reach the fiber surface and accumulate, so that the fiber surface is negatively charged. Hydrotalcite is a layered double metal hydroxide with a positive charge. Therefore, through electrostatic adsorption, the hydrotalcite with the positive charge induces self-assembly into a multi-layer core-shell structure on the aramid fiber, which to a certain extent organizes the formation and migration of oxygen-containing free radicals in the organic polymer layer, thereby improving the photothermal stability of the aramid fiber. In addition, the hydrotalcite silicone rubber has a good reinforcement effect, effectively improves the rigidity-toughness balance, and makes it have more excellent mechanical properties. In addition, the interlayer anions of the hydrotalcite are exchangeable, and the introduction of cinnamic acid into the interlayer of the hydrotalcite can improve the ultraviolet shielding ability and enhance the photothermal stability of the foamed silicone rubber.

[0013] Optionally, the preparation method of the ionic liquid modified carbon nanotubes is as follows: The tea polyphenols are added to a nanocellulose slurry having a concentration of 2-2.5 wt%, and carbon nanotubes are added. The mixture is evenly mixed and freeze-dried to prepare a mixed aerogel, wherein the mass ratio of the nanocellulose, the tea polyphenols and the carbon nanotubes is 1:1-1.25:0.5-1; The mixed aerogel and the ionic liquid are mixed and ground for 30-50 minutes to obtain ionic liquid modified carbon nanotubes, and the mass ratio of the mixed aerogel to the ionic liquid is 4-5:1.

[0014] By adopting the above technical scheme, tea polyphenols have antioxidant properties, can delay the aging performance of silicone rubber, and enhance the anti-aging ability. Nanocellulose is a polymer material with high strength, high modulus and high specific surface area. Its unique nanoscale structure enables it to form a physical cross-linked structure. The obtained aerogel can be used as a reinforcing phase to improve the tensile strength, tear strength and compression strength of silicone rubber, and can also improve the high-temperature stability of silicone rubber and reduce the molecular chain breakage caused by thermal oxidation aging. The hydroxyl groups on its surface can capture free radicals and slow down the aging rate. Tea polyphenols are polyphenols with multiple hydroxyl groups and cyclobenzene structures. Nanocellulose contains Hydroxyl groups and these structural features enable tea polyphenols and nanocellulose to interact with carbon nanotubes. Carbon nanotubes can be evenly adsorbed on the surface of the mixed aerogel, thereby reducing the agglomeration of carbon nanotubes. The addition of tea polyphenols increases the hydrogen bonds between molecules and forms a stable three-dimensional network structure, which improves the stability of the overall structure of the aerogel and the mechanical properties, making the aerogel have a strong elastic recovery rate and improving the compression deformation resistance of silicone rubber. Moreover, after grinding the ionic liquid with the mixed aerogel, a substance with high viscosity is obtained, which can increase the stability of the pore structure, enhance the elastic recovery ability, and further improve the anti-deformation effect.

[0015] Optionally, the carbon nanotubes are carbon nanotube-loaded zinc oxide particles, and the mass ratio of the carbon nanotubes to the zinc oxide is 1:0.2-0.5.

[0016] By adopting the above technical solution, zinc oxide is a new type of wide bandgap straight-band n-type semiconductor material. Carbon nanotubes are impregnated with a solution containing zinc ions to load zinc oxide-loaded particles on the carbon nanotubes. The hydroxyl groups on the carbon nanotubes provide active sites for zinc ions, so that the zinc ions are adsorbed on the carbon nanotubes, thereby improving the ultraviolet light shielding of the carbon nanotubes and improving the ultraviolet aging resistance of the silicone rubber.

[0017] Optionally, the ionic liquid is selected from one of 1-vinyl-3-ethylimidazolium bromide, 1-butyl-3-methylimidazolium chloride and 1-octyl-3-methylimidazolium tetrafluoroborate.

[0018] By adopting the above technical solution, the above ionic liquids can modify carbon nanotubes through "cation-π" bonds, thereby improving the compatibility and dispersibility of carbon nanotubes with matrix materials such as silicone rubber, and improving the rigidity-toughness balance of rubber materials.

[0019] Optionally, the melt index of the low-density polyethylene is 1.5-2 g / 10 min.

[0020] By adopting the above technical solution, the low-density polyethylene has a large melt index and good melt fluidity. In the molten state at high temperature, the viscosity is reduced, which increases the thermal motion ability of the moving unit and the activity space, thereby enhancing the activity of the molecular chain, which is conducive to the formation of bubbles.

[0021] Optionally, the compatibilizer is hydroxypropyl silicone oil modified low-density polyethylene grafted with maleic anhydride.

[0022] By adopting the above technical scheme, the low-density polyethylene grafted with maleic anhydride and hydroxypropyl silicone oil can be made to improve the compatibility of low-density polyethylene and silicone rubber, increase the heterogeneous nucleation points, increase the number of bubbles, make the pore size distribution more uniform, and reduce the average pore size, thereby achieving a better volume expansion effect, thereby improving the tensile strength and compressive stress resistance of the foamed silicone rubber and reducing the deformation of the bubbles.

[0023] Optionally, the flame retardant includes at least one of ammonium polyphosphate, calcium silicate, aluminum hydroxide and magnesium hydroxide; The vulcanizing agent is selected from sulfur or 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; The filler is selected from at least one of carbon black, calcium carbonate, silicon dioxide, kaolin, talc, glass powder, and mica powder; The lubricant is selected from at least one of hydroxy silicone oil, stearic acid, zinc stearate and polyethylene wax; The accelerator is selected from at least one of accelerator DM, accelerator TMTD and accelerator TBBS.

[0024] In a second aspect, the present application provides a method for preparing an aging-resistant sole material for boots, using the following technical solution: A preparation method of an anti-aging sole material for boots comprises the following steps: mixing silicone rubber, EPDM rubber, ethylene-octene copolymer and filler, kneading at 120-130°C, adding lubricant, low-density polyethylene and compatibilizer, adding AC foaming agent, accelerator, antioxidant and flame retardant after kneading, adding vulcanizer after kneading again, continuing kneading, letting the mixed rubber stand, hot pressing at 130-140°C and 18-20MPa, and drying at 170-180°C to obtain the anti-aging sole material for boots.

[0025] By adopting the above technical solution, the appropriate foaming temperature can make the pores grow moderately, increase the crosslinking density, make the pore size uniform and more evenly distributed, reduce the damage caused by stress concentration, and improve the mechanical properties of the rubber material.

[0026] In summary, this application has the following beneficial effects: 1. Since the present application adopts silicone rubber as the foaming substrate, adds low-density polyethylene, EPDM rubber, ethylene-octene copolymer, etc., to improve the mechanical strength of the foaming material and enhance its aging resistance, and uses POSS grafted aramid fiber and ionic liquid modified carbon nanotubes as antioxidants, the aramid fiber and carbon nanotubes can be evenly dispersed in the foaming matrix, enhancing the tensile and tearing resistance of the foaming material, while reducing the compression deformation of the pores, enhancing its compression deformation resistance, and improving the UV aging resistance and heat aging resistance of the foamed silicone rubber material.

[0027] 2. In the present application, it is preferred that the aramid fiber be subjected to oxygen plasma treatment in advance, and then mixed with hydrotalcite and cinnamic acid and vacuum-sucked to load the hydrotalcite on the surface of the aramid fiber, and the interaction between cinnamic acid and hydrotalcite is utilized to improve the light and heat stability of the aramid fiber and show better ultraviolet shielding ability.

[0028] 3. In the present application, nanocellulose, tea polyphenols and carbon nanotubes are preferably used to prepare a mixed aerogel, and then the mixed aerogel is ground with ionic liquid. The prepared ionic liquid-modified carbon nanotubes have a good effect on improving the anti-aging ability of the foamed silicone rubber material, and can also improve its compression resilience, reduce compression deformation, and improve its overall mechanical strength. DETAILED DESCRIPTION

[0029] The following examples further illustrate the present application in detail.

[0030] Preparation Examples 1-8 of POSS Grafted Aramid Fibers In the following preparation examples, the sources of the raw materials are as follows: the aramid fiber is aramid chopped fiber with a length of 3 mm, selected from Yantai Taihexing Material Technology, the amino cage silsesquioxane is selected from Xi'an Qiyue Biology, with the product number 54521, and the hydrotalcite is selected from Tianjin Jinheng Blue Ocean Technology, with the model number Jinheng F9.

[0031] Preparation Example 1: (1) Aramid fiber was placed in a 30 wt % phosphoric acid solution for 8 h, filtered, washed with deionized water, and dried at 60° C. to obtain carboxylated aramid fiber; (2) Disperse 10 g of carboxylated aramid fiber in 200 mL of tetrahydrofuran, add 5 g of N,N'-carbonyldiimidazole, activate at 60°C for 3 h, add a tetrahydrofuran solution of amino-type cage silsesquioxane (prepared by ultrasonically dispersing 10 g and 200 mL of tetrahydrofuran for 1 h) while passing nitrogen, keep the reaction at 60°C for 12 h, filter, and vacuum dry at 60°C for 72 h.

[0032] Preparation Example 2: (1) Aramid fiber was placed in a 30 wt% phosphoric acid solution for 8 h, filtered, washed with deionized water, and dried at 60° C. to obtain carboxylated aramid fiber; (2) Disperse 10 g of carboxylated aramid fiber in 200 mL of tetrahydrofuran, add 3 g of N,N'-carbonyldiimidazole, activate at 70°C for 2 h, add a tetrahydrofuran solution of amino-type cage silsesquioxane (prepared by ultrasonically dispersing 12 g and 200 mL of tetrahydrofuran for 1 h) while passing nitrogen, and react at 70°C for 10 h, filter, and vacuum dry at 60°C for 72 h.

[0033] Preparation Example 3: The difference from Preparation Example 1 is that the tetrahydrofuran solution of N,N'-carbonyldiimidazole and amino-type cage silsesquioxane is not added, and only the phosphoric acid solution is used to carboxylate the aramid fiber.

[0034] Preparation Example 4: The difference from Preparation Example 1 is that in step (1), before the aramid fiber is immersed in the phosphoric acid solution, the following treatment is carried out: 15 g of aramid fiber is treated with oxygen plasma, then dispersed in 100 g of deionized water, 0.2 g of hydrotalcite and 0.2 g of cinnamic acid are added, and after ultrasonic treatment at 600 W for 5 min, vacuum suction is carried out at 0.05 MPa for 12 h, and dried at 30°C for 24 h. The oxygen pressure value of the oxygen plasma treatment is 0.1 MPa, the vacuum degree is 100 Pa, the power is 250 W, and the treatment time is 120 s.

[0035] Preparation Example 5: The difference from Preparation Example 1 is that in step (1), before the aramid fiber is immersed in the phosphoric acid solution, the following treatment is carried out: 15 g of aramid fiber is treated with oxygen plasma, then dispersed in 100 g of deionized water, 0.1 g of hydrotalcite and 0.1 g of cinnamic acid are added, and after ultrasonic treatment at 600 W for 5 min, vacuum suction is carried out at 0.08 MPa for 10 h, and dried at 30°C for 24 h. The oxygen pressure value of the oxygen plasma treatment is 0.1 MPa, the vacuum degree is 100 Pa, the power is 250 W, and the treatment time is 120 s.

[0036] Preparation Example 6: The difference from Preparation Example 4 is that cinnamic acid is not added.

[0037] Preparation Example 7: The difference from Preparation Example 4 is that cinnamic acid and hydrotalcite are not added.

[0038] Preparation Example 8: The difference from Preparation Example 4 is that the aramid fiber is not treated with oxygen plasma.

[0039] Preparation Examples 9-13 of Ionic Liquid Modified Carbon Nanotubes In the following preparation examples, the sources of various raw materials are: nanocellulose is selected from Zhejiang Jinjiahao Green Nanotechnology, model CNF-85, and carbon nanotubes are multi-walled carbon nanotubes selected from Sichuan Kenye Technology, model KYMWC1.

[0040] Preparation Example 9: The carbon nanotubes and the ionic liquid were mixed and then ground for 30 minutes, the mass ratio of the carbon nanotubes to the ionic liquid was 1:4, and the ionic liquid was 1-vinyl-3-ethylimidazolium bromide.

[0041] Preparation Example 10: 4 g of nanocellulose was dispersed in deionized water to form a nanocellulose slurry with a concentration of 2.5 wt %; 5g of tea polyphenols were added to the nanocellulose slurry, and 4g of carbon nanotubes were added. After mixing evenly, the mixture was freeze-dried to obtain a mixed aerogel. The carbon nanotubes were carbon nanotube-loaded zinc oxide particles. The specific preparation method was as follows: 0.5mol / L of urea and 1.5mol / L of sodium hydroxide were dissolved in 20mL of distilled water, and the carbon nanotubes were added to obtain a mixed solution. The mixed solution was added to 20mL of a 0.1mol / L zinc sulfate solution, and the mixture was heated to 150°C, stirred for 3h, filtered, washed, and dried. The mass ratio of the carbon nanotubes to the zinc oxide was 1:0.5. The mixed aerogel and the ionic liquid were mixed and ground for 30 minutes to obtain ionic liquid modified carbon nanotubes. The mass ratio of the mixed aerogel to the ionic liquid was 4:1, and the ionic liquid was 1-vinyl-3-ethylimidazolium bromide.

[0042] Preparation Example 11: 4 g of nanocellulose was dispersed in deionized water to form a nanocellulose slurry with a concentration of 2 wt%; 4g of tea polyphenols were added to the nanocellulose slurry, and 2g of carbon nanotubes were added. After mixing evenly, the mixture was freeze-dried to obtain a mixed aerogel. The carbon nanotubes were carbon nanotube-loaded zinc oxide particles. The specific preparation method was as follows: 0.5mol / L of urea and 1.5mol / L of sodium hydroxide were dissolved in 20mL of distilled water, and the carbon nanotubes were added to obtain a mixed solution. The mixed solution was added to 20mL of a 0.1mol / L zinc sulfate solution, and the mixture was heated to 150°C, stirred for 3h, filtered, washed, and dried. The mass ratio of the carbon nanotubes to the zinc oxide was 1:0.2. The mixed aerogel and the ionic liquid were mixed and ground for 30 minutes to obtain ionic liquid modified carbon nanotubes. The mass ratio of the mixed aerogel to the ionic liquid was 5:1, and the ionic liquid was 1-butyl-3-methylimidazolium chloride.

[0043] Preparation Example 12: The difference from Preparation Example 10 is that no zinc oxide particles are loaded on the carbon nanotubes.

[0044] Preparation Example 13: The difference from Preparation Example 10 is that tea polyphenols are not added. Example

[0045] Embodiment 1: A kind of anti-aging sole material for boots, the raw material dosage is as shown in Table 1, wherein the silicone rubber is vinyl silicone rubber, selected from Shenzhen Anchengxing Technology, with a brand of 110-2, and a vinyl content of 0.23%, the EPDM rubber is selected from Dow of the United States, with a brand of 4520, the melt index of low-density polyethylene is 2g / 10min, selected from Singapore Polyolefin, model LD185JD, the ethylene-octene copolymer is selected from Dow of the United States, with a brand of 8003, the vulcanizing agent is sulfur, the filler is carbon black 330, the accelerator is accelerator DM, the lubricant is stearic acid, the antioxidant comprises POSS grafted aramid fiber and ionic liquid modified carbon nanotubes in a mass ratio of 1.5:1, the POSS grafted aramid fiber Prepared by Preparation Example 1, ionic liquid modified carbon nanotubes are prepared by Preparation Example 9, the flame retardant is ammonium polyphosphate and calcium silicate in a mass ratio of 1:1, and the compatibilizer is hydroxypropyl silicone oil modified low-density polyethylene grafted maleic anhydride. The preparation method is: 12g low-density polyethylene grafted maleic anhydride is mixed with 240g xylene, stirred and dissolved at 120°C, 5g concentrated sulfuric acid and 58g hydroxypropyl silicone oil are added, and the reaction is filtered and washed after 8 hours, and the filter cake is dried at 60°C to constant weight, wherein the low-density polyethylene grafted maleic anhydride is selected from Dongguan Sujia Polymer Raw Materials, with a brand name of IM300N, and the hydroxypropyl silicone oil is a double-ended hydroxypropyl silicone oil selected from Wuhan Lanabai Pharmaceutical Chemical, with a model of EFWE32 and a product number of AEF3434.

[0046] The method for preparing the above-mentioned anti-aging sole material for boots comprises the following steps: Silicone rubber, EPDM rubber, ethylene-octene copolymer and filler are mixed, kneaded at 120°C for 10 minutes, lubricant, low-density polyethylene and compatibilizer are added, AC foaming agent, accelerator, antioxidant and flame retardant are added after kneading for 10 minutes, vulcanizer is added after kneading again for 10 minutes, and kneading is continued for 10 minutes. After the kneaded rubber is allowed to stand for 24 hours, it is hot-pressed at 130°C and 20MPa, and dried at 170°C for 4 hours to obtain an aging-resistant sole material for boots.

[0047] Table 1 Amount of raw materials used for the aging-resistant sole material for boots in Examples 1-3 Raw material / kg Example 1 Example 2 Example 3 Silicone Rubber 75 80 70 EPDM 25 20 30 Low density polyethylene 9 10 8 Ethylene-octene copolymer 6 8 5 Compatibilizer 3.5 4 3 Vulcanizing agent 1.1 1.2 1 filler 33 37 30 Accelerator 1.5 3 0.5 AC foaming agent 18 20 19 Lubricants 2 3 1 Antioxidant 1.4 2 1 Flame retardants 0.4 0.5 0.25 Embodiment 2: A kind of anti-aging sole material for boots, the raw material dosage is as shown in Table 1, wherein the silicone rubber is vinyl silicone rubber, selected from Shenzhen Anchengxing Technology, with a grade of 110-2 and a vinyl content of 0.23%, the EPDM rubber is selected from Dow of the United States, with a grade of 4520, the melt index of low-density polyethylene is 1.5g / 10min, selected from Daqing Petrochemical, with a model of 18D, the ethylene-octene copolymer is selected from Dow of the United States, with a grade of 8003, the vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane, the filler is calcium carbonate, the accelerator is accelerator TMTD, the lubricant is polyethylene wax, and the antioxidant includes POSS grafted aramid fiber and ionic liquid modified polyol with a mass ratio of 1:1. The carbon nanotubes are prepared by Preparation Example 2, the POSS grafted aramid is prepared by Preparation Example 2, the ionic liquid modified carbon nanotubes are prepared by Preparation Example 9, the flame retardant is aluminum hydroxide, and the compatibilizer is hydroxypropyl silicone oil modified low-density polyethylene grafted maleic anhydride. The preparation method is: 12g low-density polyethylene grafted maleic anhydride is mixed with 240g xylene, stirred and dissolved at 120°C, 5g concentrated sulfuric acid and 58g hydroxypropyl silicone oil are added, and the reaction is filtered and washed after 8h, and the filter cake is dried at 60°C to constant weight, wherein the low-density polyethylene grafted maleic anhydride is selected from Dongguan Sujia Polymer Raw Materials, with a brand name of IM300N, and the hydroxypropyl silicone oil is a double-terminal hydroxypropyl silicone oil selected from Wuhan Lanabai Pharmaceutical Chemical, with a model of EFWE32 and a product number of AEF3434.

[0048] The method for preparing the above-mentioned anti-aging sole material for boots comprises the following steps: Silicone rubber, EPDM rubber, ethylene-octene copolymer and filler are mixed, kneaded at 130°C for 8 minutes, lubricant, low-density polyethylene and compatibilizer are added, AC foaming agent, accelerator, antioxidant and flame retardant are added after kneading for 8 minutes, vulcanizer is added after kneading again for 8 minutes, and kneading is continued for 5 minutes. After the mixed rubber is allowed to stand for 20 hours, it is hot-pressed at 140°C and 18MPa, and dried at 180°C for 2 hours to obtain an aging-resistant sole material for boots.

[0049] Embodiment 3: A kind of anti-aging sole material for boots, the raw material dosage is as shown in Table 1, wherein the silicone rubber is vinyl silicone rubber, selected from Shenzhen Anchengxing Technology, brand 110-2, vinyl content 0.23%, EPDM rubber is selected from Dow, USA, brand 4520, low density polyethylene melt index is 1.5g / 10min, selected from Daqing Petrochemical, model 18D, ethylene-octene copolymer is selected from Dow, USA, brand 8003, vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane, filler is silicon dioxide, accelerator includes accelerator TD and accelerator TMTD with a mass ratio of 1:1, lubricant is zinc stearate, antioxidant includes POSS grafted aromatic with a mass ratio of 1.3:1 The invention discloses a method for preparing a polyurethane foam composite fiber and an ionic liquid modified carbon nanotube, wherein the POSS grafted aramid fiber is prepared by Preparation Example 1, the ionic liquid modified carbon nanotube is prepared by Preparation Example 9, the flame retardant is aluminum hydroxide, and the compatibilizer is hydroxypropyl silicone oil modified low-density polyethylene grafted maleic anhydride. The preparation method is as follows: 12g low-density polyethylene grafted maleic anhydride is mixed with 240g xylene, and the mixture is stirred and dissolved at 120°C, 5g concentrated sulfuric acid and 58g hydroxypropyl silicone oil are added, and the mixture is filtered and washed after reacting for 8h, and the filter cake is dried at 60°C to constant weight, wherein the low-density polyethylene grafted maleic anhydride is selected from Dongguan Sujia Polymer Raw Materials, with the brand name IM300N, and the hydroxypropyl silicone oil is a double-terminal hydroxypropyl silicone oil, which is selected from Wuhan Lanabai Pharmaceutical Chemical, with the model number EFWE32 and the item number AEF3434.

[0050] The method for preparing the above-mentioned anti-aging sole material for boots comprises the following steps: Silicone rubber, EPDM rubber, ethylene-octene copolymer and filler are mixed, kneaded at 120°C for 8 minutes, lubricant, low-density polyethylene and compatibilizer are added, AC foaming agent, accelerator, antioxidant and flame retardant are added after kneading for 10 minutes, vulcanizer is added after kneading again for 8 minutes, and kneading is continued for 8 minutes. After the mixed rubber is allowed to stand for 220 hours, it is hot-pressed at 130°C and 18MPa, and dried at 170°C for 2 hours to obtain an aging-resistant sole material for boots.

[0051] Example 4: An aging-resistant sole material for boots, which is different from Example 1 in that the POSS grafted aramid is made from Preparation Example 3.

[0052] Example 5: An aging-resistant sole material for boots, which is different from Example 1 in that the POSS grafted aramid is made from Preparation Example 4.

[0053] Example 6: An aging-resistant sole material for boots, which is different from Example 1 in that the POSS grafted aramid is made from Preparation Example 5.

[0054] Example 7: An aging-resistant sole material for boots, which is different from Example 5 in that the POSS grafted aramid is made from Preparation Example 6.

[0055] Example 8: An aging-resistant sole material for boots, which is different from Example 5 in that the POSS grafted aramid is made from Preparation Example 7.

[0056] Example 9: An aging-resistant sole material for boots, which is different from Example 5 in that the POSS grafted aramid is made from Preparation Example 8.

[0057] Example 10: An aging-resistant sole material for boots, which is different from Example 5 in that the ionic liquid-modified carbon nanotubes are made from Preparation Example 10.

[0058] Example 11: An aging-resistant sole material for boots, which is different from Example 5 in that the ionic liquid-modified carbon nanotubes are made from Preparation Example 11.

[0059] Example 12: An aging-resistant sole material for boots, which is different from Example 10 in that the ionic liquid-modified carbon nanotubes are made from Preparation Example 12.

[0060] Example 13: An aging-resistant sole material for boots, which is different from Example 10 in that the ionic liquid-modified carbon nanotubes are made from Preparation Example 13.

[0061] Comparative Example Comparative Example 1: An anti-aging sole material for boots, which differs from Example 1 in that an equal amount of ionic liquid-modified carbon nanotubes is used in the antioxidant to replace an equal amount of POSS grafted aramid fibers.

[0062] Comparative Example 2: An anti-aging sole material for boots, which is different from Example 1 in that no ionic liquid-modified carbon nanotubes are added to the antioxidant.

[0063] Comparative Example 3: An anti-aging sole material for boots, which is different from Example 1 in that the aramid fiber in the antioxidant has not been subjected to any modification treatment.

[0064] Comparative Example 4: An anti-aging sole material for boots, which is different from Example 1 in that the antioxidant is 2,2,4-trimethyl-1,2-dihydroquinoline polymer (anti-aging agent RD).

[0065] Comparative Example 5: An aging-resistant sole material for boots, which differs from Example 1 in that an equal amount of low-density polyethylene is used to replace the ethylene-octene copolymer.

[0066] Performance testing The rubber material was prepared according to the methods in the examples and comparative examples, and the performance was tested according to the following methods. The test results are recorded in Table 2.

[0067] 1. Tensile properties: Tested in accordance with GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber".

[0068] 2. Tear resistance: Tested in accordance with GB / T529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-type, right-angle and crescent-shaped specimens)".

[0069] 3. Heat aging performance: The rubber material is hung in a 300°C blast oven. After heat aging for 12 hours, its tensile strength and tear strength are tested again, and the rate of change compared with the initial value is calculated.

[0070] 4. UV-heat aging: The test equipment: UV lamp (40W, λmax=300nm) and a clean table with a 50×50cm heating plate (40cm directly below the lamp). The sample is placed on the plate and aged for 12 hours at a fixed time and temperature. The tensile strength and tear strength are tested again, and the rate of change with the initial value is calculated.

[0071] 5. Compression set rate: The test is carried out in accordance with GB / T7759-1996 "Determination of compression set of vulcanized rubber and thermoplastic rubber at room temperature, high temperature and low temperature". The test temperature is 125℃ and the test time is 72h.

[0072] Table 2 Performance test of aging-resistant rubber materials for boots Combining the data in Table 2 with the raw materials in Examples 1-3, it can be seen that the rubber materials prepared in Examples 1-3 have strong initial mechanical strength, and after heat aging and UV aging, the decrease rate of tensile strength and tear strength is small, and at the same time, they have good resistance to compression deformation.

[0073] In Example 4, compared with Example 1, the POSS grafted aramid fiber prepared in Preparation Example 3 was used. Compared with Preparation Example 1, the aramid fiber was not immersed in phosphoric acid solution, and the surface of the aramid fiber was not carboxylated. Therefore, N,N'-carbonyldiimidazole could not graft POSS on the surface of the aramid fiber. It can be seen that the initial tensile strength and tear strength of the rubber material decreased, and after heat aging and UV aging, the change rate of tensile strength and tear strength increased, while the compression permanent deformation rate did not change significantly.

[0074] In Example 5 and Example 6, the POSS grafted aramid fibers prepared in Preparation Example 4 and Preparation Example 5 were used respectively. Compared with Preparation Example 1, the aramid fibers were pretreated with oxygen plasma, hydrotalcite, cinnamic acid, etc. in Preparation Examples 4 and 5. It can be seen that the tensile strength and tear strength of the rubber materials prepared in this way are increased, the heat aging resistance and UV aging resistance are increased, and the compression permanent deformation is further reduced, indicating that the pretreatment of the aramid fibers can effectively improve the initial mechanical strength of the rubber materials, increase the anti-aging ability, and improve the anti-deformation ability.

[0075] In Example 7, the POSS grafted aramid fiber prepared in Preparation Example 6 was used, to which cinnamic acid was not added. Compared with Example 5, the tensile strength, breaking strength and compression deformation resistance of the rubber material did not change much, but its resistance to ultraviolet aging and heat aging was reduced.

[0076] Example 8 Compared with Example 5, the POSS grafted aramid fiber prepared in Preparation Example 7 was used without adding cinnamic acid and hydrotalcite. It can be seen that the compression permanent deformation rate is slightly increased, and the heat aging resistance and ultraviolet aging resistance are reduced.

[0077] In Example 9, the POSS grafted aramid fiber prepared in Preparation Example 8 is used, wherein the aramid fiber is not treated with oxygen plasma, so that the negative charge cannot be carried on the surface of the aramid fiber, and therefore, no electrostatic adsorption effect can be generated with the hydrotalcite. Compared with Example 5, it can be seen that the UV resistance and aging resistance of the rubber material are slightly reduced.

[0078] Compared with Example 5, Example 10 and Example 11 respectively use the ionic liquid modified carbon nanotubes prepared in Preparation Example 10 and Preparation Example 11, and use nanocellulose, tea polyphenols and carbon nanotubes to prepare mixed aerogels, which are then ground with ionic liquids. The ionic liquid modified carbon nanotubes thus prepared can increase the mechanical properties of the rubber material, while increasing its anti-aging ability and improving its compression deformation ability.

[0079] Example 12 and Example 13 respectively use the ionic liquid modified carbon nanotubes prepared in Preparation Example 12 and Preparation Example 13. In Preparation Example 12, zinc oxide is not loaded on the carbon nanotubes, and in Preparation Example 13, tea polyphenols are not added. Compared with Example 10, the rubber materials prepared in Example 12 and Example 13 have reduced resistance to ultraviolet aging and heat aging.

[0080] Compared with Example 1, in Comparative Example 1, the antioxidant is ionic liquid modified carbon nanotubes. The data in Table 2 show that the initial tensile strength and tear strength of the rubber material decrease, and the aging resistance weakens, and the compression deformation increases.

[0081] In Comparative Example 2, no ionic liquid modified carbon nanotubes were added, and only POSS grafted aramid fibers were used. Compared with Example 1, the mechanical strength such as tensile strength of the rubber material decreased, and the aging resistance was weakened, and the overall decrease was higher than that in Comparative Example 1.

[0082] Compared with Example 1, in Comparative Example 3, the aramid fiber is not subjected to POSS grafting treatment. It can be seen that the rubber material prepared in Comparative Example 3 has poor initial tensile strength and other properties, and its anti-aging ability is reduced.

[0083] Comparative Example 4 uses an equal amount of antioxidant RD to replace ionic liquid modified carbon nanotubes and POSS grafted aramid fibers. It can be seen that its improvement in the resistance to ultraviolet aging and thermal oxidation of rubber materials is not as good as the antioxidant of the present application, and the compression deformation rate is increased, and the deformation resistance is poor.

[0084] In Comparative Example 5, low-density polyethylene is used instead of ethylene-octene copolymer. It can be seen that the tensile strength and tear strength of the rubber material decrease, and the compression deformation rate increases, indicating that excessive use of low-density polyethylene will lead to stress concentration, decreased mechanical properties, and more energy dissipated in the process of molecular chain recovery deformation, resulting in weakened compression rebound ability.

[0085] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An anti-aging sole material for boots, characterized in that: The invention comprises the following raw materials in parts by weight: 70-80 parts of silicone rubber, 20-30 parts of EPDM rubber, 8-10 parts of low-density polyethylene, 5-8 parts of ethylene-octene copolymer, 3-4 parts of compatibilizer, 1-1.2 parts of vulcanizer, 30-37 parts of filler, 0.5-3 parts of accelerator, 18-20 parts of AC foaming agent, 1-3 parts of lubricant, 1-2 parts of antioxidant, 0.25-0.5 parts of flame retardant; The antioxidant comprises POSS grafted aramid fiber and ionic liquid modified carbon nanotube in a mass ratio of 1-1.5:

1.

2. The anti-aging sole material for boots according to claim 1, characterized in that: Described POSS grafted aramid fiber is made by the following method: The aramid fiber is immersed in a phosphoric acid solution, filtered, washed and dried to obtain the carboxylated aramid fiber; The carboxylated aramid fiber is dispersed in tetrahydrofuran, N,N'-carbonyldiimidazole is added, and the mixture is activated at 60-70°C. A tetrahydrofuran solution of amino cage silsesquioxane is added while nitrogen is introduced, and the mixture is kept warm for 10-12 hours, filtered, and dried. The mass ratio of the carboxylated aramid fiber, N,N'-carbonyldiimidazole, and amino cage silsesquioxane is 1:0.3-0.5:1-1.

2.

3. The anti-aging sole material for boots according to claim 2, characterized in that: Before the aramid fiber is immersed in the phosphoric acid solution, the following pretreatment is performed: The aramid fiber was treated with oxygen plasma, then dispersed in deionized water, hydrotalcite and cinnamic acid were added, ultrasonically treated, vacuum pumped at 0.05-0.08 MPa for 10-12 h, and dried. The mass ratio of aramid fiber, hydrotalcite, cinnamic acid and deionized water was 15:0.1-0.2:0.1-0.2:

100.

4. The anti-aging sole material for boots according to claim 1, characterized in that: The preparation method of the ionic liquid modified carbon nanotube is as follows: The tea polyphenols are added to a nanocellulose slurry having a concentration of 2-2.5 wt%, and carbon nanotubes are added. The mixture is mixed evenly and freeze-dried to prepare a mixed aerogel, wherein the mass ratio of the nanocellulose, the tea polyphenols and the carbon nanotubes is 1:1-1.25:0.5-1; The mixed aerogel and the ionic liquid are mixed and ground for 30-50 minutes to obtain ionic liquid modified carbon nanotubes, and the mass ratio of the mixed aerogel to the ionic liquid is 4-5:

1.

5. The anti-aging sole material for boots according to claim 4, characterized in that: The carbon nanotubes are carbon nanotube-loaded zinc oxide particles, and the mass ratio of the carbon nanotubes to the zinc oxide is 1:0.2-0.

5.

6. The anti-aging sole material for boots according to claim 4, characterized in that: The ionic liquid is selected from one of 1-vinyl-3-ethylimidazolium bromide, 1-butyl-3-methylimidazolium chloride and 1-octyl-3-methylimidazolium tetrafluoroborate.

7. The anti-aging sole material for boots according to claim 1, characterized in that: The low-density polyethylene has a melt index of 1.5-2 g / 10 min.

8. The anti-aging sole material for boots according to claim 1, characterized in that: The compatibilizer is hydroxypropyl silicone oil modified low-density polyethylene grafted with maleic anhydride.

9. The anti-aging sole material for boots according to claim 1, characterized in that: The flame retardant comprises at least one of ammonium polyphosphate, calcium silicate, aluminum hydroxide and magnesium hydroxide; The vulcanizing agent is selected from sulfur or 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; The filler is selected from at least one of carbon black, calcium carbonate, silicon dioxide, kaolin, talc, glass powder, and mica powder; The lubricant is selected from at least one of hydroxy silicone oil, stearic acid, zinc stearate and polyethylene wax; The accelerator is selected from at least one of accelerator DM, accelerator TMTD and accelerator TBBS.

10. The method for preparing the anti-aging sole material for boots according to any one of claims 1 to 9, characterized in that: The following steps are involved: Silicone rubber, EPDM rubber, ethylene-octene copolymer and filler are mixed, and lubricant, low-density polyethylene and compatibilizer are added during kneading at 120-130°C. AC foaming agent, accelerator, antioxidant and flame retardant are added after kneading. Vulcanizer is added after kneading again, and kneading is continued. After the mixed rubber is allowed to stand, hot pressing is performed at 130-140°C and 18-20MPa, and drying is performed at 170-180°C to obtain an aging-resistant sole material for boots.

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