TPE composite material for elastic tube and preparation method thereof

Abstract

This invention discloses a TPE composite material for elastic tubes and its preparation method. The TPE composite material, by weight, comprises 80-120 parts of styrene-based thermoplastic elastomer, 60-80 parts of white oil, 5-15 parts of polyolefin elastomer, 10-20 parts of rigid material, 10-30 parts of inorganic filler, 2-5 parts of lubricant, 2-5 parts of compatibilizer, and 5-15 parts of modified carbon black. The preparation method of the modified carbon black includes mixing carbon black, a quaternary ammonium salt cationic surfactant, and a fatty amine, followed by ultrasonic treatment to obtain the modified carbon black. This invention modifies carbon black by intercalating it with a fatty amine, improving the specific surface area of ​​the carbon black. The addition of modified carbon black enhances the tensile strength and resilience of the TPE composite material, while also improving its resistance to ultraviolet aging. The TPE composite material of this invention has widely available raw materials and a simple preparation process, making it suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of composition technology of vinyl aromatic monomers and conjugated diene block copolymers, and particularly to a TPE composite material for elastic tubes and its preparation method. Background Technology

[0002] Elastic resistance bands (or resistance ropes) are portable strength training equipment that improves muscle strength, endurance, and flexibility by generating resistance when stretched. They are widely used in home fitness, rehabilitation training, and outdoor sports, and are popular due to their portability and ability to simulate various machine movements. Thermoplastic elastomers (TPEs) possess excellent elasticity and high resilience, quickly returning to their original shape after being subjected to external force. They also have good weather resistance and are safe and environmentally friendly, making them the mainstream material for manufacturing elastic resistance bands.

[0003] Currently, styrene-based thermoplastic elastomers account for the largest share of usage, including styrene-butadiene-styrene block copolymers (SBS), styrene-isoprene-styrene block copolymers (SIS), styrene-ethylene / butene-styrene block copolymers (SEBS), and styrene-ethylene / propylene-styrene block copolymers (SEPS). Improving the durability and applicability of elastic tubes is the current market trend. CN113416375A discloses a TPE material for extruded fitness equipment tension tubes and its molding process. The raw material components in the TPE material are as follows by mass: SEBS 85~125 parts, polypropylene 30~70 parts, inorganic additives 20~40 parts, plasticizer 20~40 parts, rubber additives 3~5 parts, crosslinking agent 1~3 parts, polypropylene nucleating agent 1~2 parts, plastic antibacterial agent 0.1~1 part, heat stabilizer 2~3 parts, antifungal agent 4~7 parts, and activated carbon 1~5 parts. This method utilizes an organometallic compound formed by combining organotin compounds and o-phenylphenol to create an antifungal agent, thereby improving the antibacterial properties and extending the service life of TPE materials. However, o-phenylphenol is classified as a Group 3 carcinogen, and organotin compounds have high irritant properties. CN114773768A discloses a TPE resistance band material and its preparation method. The material, by weight, comprises 100 parts SEBS, 10 parts poly(pentafluoroallyl fluorosulfate), 80-120 parts white oil, 2-5 parts PP, 2-5 parts POE, 0.1-0.5 parts antioxidant, 0.1-0.5 parts light stabilizer, and 1-3 parts silicone. This TPE resistance band material can significantly improve the compression set performance of resistance bands and extend their service life. However, the high proportion of poly(pentafluoroallyl fluorosulfate) in its formulation reduces the strength of the composite material, and segregation may occur with long-term use.

[0004] There is still a need to provide a safe, environmentally friendly, highly elastic, and stable TPE composite material. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a TPE composite material for elastic tubes, comprising, by weight, 80-120 parts of styrene-based thermoplastic elastomer, 60-80 parts of white oil, 5-15 parts of polyolefin elastomer, 10-20 parts of rigid material, 10-30 parts of inorganic filler, 2-5 parts of lubricant, 2-5 parts of compatibilizer, and 5-15 parts of modified carbon black; The method for preparing the modified carbon black includes, Modified carbon black is obtained by mixing carbon black, quaternary ammonium salt cationic surfactant, and fatty amine and then ultrasonically treating the mixture.

[0006] This invention uses styrene-based elastomers as the matrix to provide the main elasticity and processability of modified TPE materials. White oil, a mixture of refined liquid hydrocarbons derived from petroleum, primarily a mixture of saturated alkanes and chain alkanes, can reduce hardness and improve melt flow during processing. Polyethylene and / or polypropylene possess excellent flexibility, chemical resistance, and processing performance; as relatively inexpensive plastic materials, their addition to the matrix can also reduce costs. Polyolefin elastomers (POEs), with their superior molecular chain flexibility compared to pure SEBS, not only increase the toughness of composite materials but also reduce density, contributing to lightweight design. Inorganic fillers can improve the rigidity and dimensional stability of composite materials, but their addition should not be excessive. Lubricants can reduce extruder screw torque, improving the user experience. Compatibilizers can increase the dispersibility of inorganic components, enhance the adhesion between inorganic components and the matrix interface, and improve overall performance.

[0007] Carbon black's structure is neither typical layered (like graphene) nor simple spherical or blocky, but rather possesses a unique quasi-graphitic microcrystalline aggregate morphology, somewhere between "branched clusters" and "twisted layers." Its specific surface area ranges extremely wide (5~1500 m²). 2 (g), specifically depending on the production process and application. This invention uses fatty amines to intercalate carbon black. Under ultrasonication, the fatty amines penetrate into the layered structure or pores of the carbon black. Their long-chain alkyl groups widen the interlayer spacing of the carbon black microcrystals, exposing more internal surface area and thus increasing the specific surface area. Surfactants can reduce interfacial tension, improve the wettability of fatty amines on the carbon black surface, and optimize intercalation uniformity. Among different types of surfactants, quaternary ammonium cationic surfactants have a stronger promoting ability compared to anionic and nonionic surfactants. This may be because the presence of ammonium ions can further enhance the interaction between fatty amines and carbon black, improve the intercalation effect, and increase the surface area of ​​the carbon black.

[0008] Furthermore, the mass ratio of the carbon black, the quaternary ammonium salt cationic surfactant, and the fatty amine is 2~10:0.2~0.5:50~100; The ultrasonic treatment was performed at 100-200W for 1-3 hours. The fatty amine is selected from straight-chain alkylamines with 12 to 18 carbon atoms.

[0009] Intercalated carbon black is immersed in a zinc ion solution. After adsorbing zinc ions, the zinc is reduced under heat treatment, enabling in-situ etching of the carbon black. The reduced zinc on the carbon black surface further increases the specific surface area under low zinc ion concentration, enhancing the interaction between carbon black and other materials. Simultaneously, the modified carbon black prepared under these conditions significantly improves the UV aging resistance of composite materials.

[0010] Furthermore, after ultrasonic treatment, the obtained product is soaked in a zinc ion solution and stirred for 2-5 hours to obtain a precursor; the precursor is then heat-treated to obtain modified carbon black.

[0011] Furthermore, the concentration of the zinc ion solution is 0.01~0.05 mol / L; The heat treatment is carried out in a protective gas atmosphere at 600~900℃ for 1~5 hours.

[0012] The ratio of the product to the zinc ion solution does not need to be strictly limited. Preferably, the mass ratio of the product to the zinc ion solution is 5~10:50~150.

[0013] It should be noted that the type of styrene-based elastomer in this invention is not strictly limited. Exemplarily, it can be at least one of styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene / butene-styrene block copolymer (SEBS), and styrene-ethylene / propylene-styrene block copolymer (SEPS). The solute and solvent of the zinc ion solution are not strictly limited. Exemplarily, the solute can be at least one of zinc nitrate hexahydrate, zinc chloride, and zinc acetate dihydrate; the solvent can be at least one of water, ethanol, acetone, dimethyl sulfoxide, and N,N-dimethylacetamide.

[0014] Furthermore, the rigid material includes at least one of polyethylene and polypropylene.

[0015] Furthermore, the inorganic filler includes at least one of titanium dioxide (2000-3000 mesh), calcium carbonate, barium sulfate, and talc.

[0016] Furthermore, the lubricant includes at least one of stearic acid, magnesium stearate, zinc stearate, ethylene bis-stearamide, erucamide, paraffin wax, polypropylene wax, polyethylene wax, oleamide, and silicone.

[0017] Furthermore, the compatibilizer includes at least one of maleic anhydride-grafted polypropylene, maleic anhydride-grafted styrene-ethylene-butene block copolymer, and vinylpyridine-grafted styrene-ethylene-butene block copolymer.

[0018] This invention also provides a method for preparing the above-mentioned TPE composite material for elastic tubes, including, A mixture is prepared by mixing styrene-based thermoplastic elastomers with white oil. The mixture is combined with polyolefin elastomer, rigid material, inorganic filler, lubricant, compatibilizer and modified carbon black and then extruded and granulated to obtain TPE composite material for elastic tubes.

[0019] The present invention also provides the application of the above-mentioned TPE composite material for elastic tubes in fitness equipment.

[0020] Compared with the prior art, the present invention has the following beneficial effects: This invention modifies carbon black by intercalation with aliphatic amines, improving the specific surface area of ​​the carbon black. The addition of modified carbon black enhances the tensile strength and resilience of the TPE composite material, while also improving its resistance to ultraviolet aging. The TPE composite material of this invention has widely available raw materials and a simple preparation process, making it suitable for industrial production. Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0022] Description of some of the raw materials used in the embodiments and comparative examples of this invention: The styrene-based elastomer selected was SEBS, model YH-503, purchased from Baling Petrochemical Co., Ltd. White oil, model KN4010, purchased from Dongguan Beishan Lubricating Oil Co., Ltd. Polyolefin elastomer, grade 8150, purchased from Dow Chemical Company, USA; Polypropylene, model T30S, purchased from Sinopec Shanghai Engineering Co., Ltd. Maleic anhydride-grafted polypropylene, grade 50E725, purchased from DuPont, USA. Carbon black, type N220, has a specific surface area of ​​approximately 115.3 m². 2 / g, purchased from Hefeng New Energy Co., Ltd.

[0023] All other unmentioned raw materials are common raw materials. The above content is only for illustrative purposes and should not be construed as a strict limitation of the present invention. Those skilled in the art can directly purchase commercially available raw materials or prepare the same / similar raw materials themselves. These contents will not be repeated in the embodiments.

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1 A method for preparing a TPE composite material for elastic tubes, comprising the following steps: S1. Weigh 100kg SEBS, 75kg white oil, 5kg polyolefin elastomer, 15kg polypropylene, 20kg 2500 mesh calcium carbonate, 3kg polyethylene wax, 3kg maleic anhydride grafted polypropylene and 7kg modified carbon black. S2. After drying SEBS at 100℃ for 3 hours, it is added to a mixer with white oil and stirred at 80℃ and 500 rpm for 30 minutes. Then, polyolefin elastomer, polypropylene, calcium carbonate, polyethylene wax, maleic anhydride grafted polypropylene and modified carbon black are added. The temperature is maintained at 80℃ and the speed is increased to 800 rpm and stirring is continued for 20 minutes. Then, the temperature is increased to 175℃ and stirred at 350 rpm for 15 minutes to obtain the premix. S3. The premixed material is fed into a twin-screw extruder for extrusion granulation to obtain the modified TPE material.

[0026] The preparation method of modified carbon black is as follows: 7.5 kg of carbon black, 0.3 kg of dodecyl dimethyl benzyl ammonium chloride, and 60 kg of n-pentadecanine were ultrasonically treated at 350 rpm and 150 W for 2 hours. After treatment, the mixture was washed three times each with acetone and water, and then dried at 120 °C for 12 hours to obtain modified carbon black.

[0027] Example 2 A method for preparing a TPE composite material for elastic tubes, comprising the following steps: S1. Weigh 100kg SEBS, 75kg white oil, 5kg polyolefin elastomer, 15kg polypropylene, 20kg 2500 mesh calcium carbonate, 3kg polyethylene wax, 3kg maleic anhydride grafted polypropylene and 7kg modified carbon black. S2. After drying SEBS at 100℃ for 3 hours, it is added to a mixer with white oil and stirred at 80℃ and 500 rpm for 30 minutes. Then, polyolefin elastomer, polypropylene, calcium carbonate, polyethylene wax, maleic anhydride grafted polypropylene and modified carbon black are added. The temperature is maintained at 80℃ and the speed is increased to 800 rpm and stirring is continued for 20 minutes. Then, the temperature is increased to 175℃ and stirred at 350 rpm for 15 minutes to obtain the premix. S3. The premixed material is fed into a twin-screw extruder for extrusion granulation to obtain the modified TPE material.

[0028] The preparation method of modified carbon black is as follows: T1. 7.5 kg of carbon black, 0.3 kg of dodecyl dimethyl benzyl ammonium chloride, and 60 kg of n-pentadecanine were ultrasonically treated at 350 rpm and 150 W for 2 hours. After the treatment, the mixture was washed three times with acetone and three times with water, and then dried at 120 °C for 12 hours to obtain intercalated carbon black. T2. Soak 5 kg of intercalated carbon black in 60 kg of 0.01 mol / L zinc chloride aqueous solution and stir at 300 rpm for 3 h. Then filter and collect the insoluble matter and dry it at 120 ℃ for 8 h to obtain the precursor. Then calcine the precursor at 800 ℃ under nitrogen atmosphere for 2 h. After the calcination, let it cool naturally. Wash the black solid with water and ethanol three times each and then transfer it to 120 ℃ to dry for 12 h to obtain modified carbon black.

[0029] Example 3 and Example 4 The method is basically the same as Example 2, except that the concentrations of zinc chloride aqueous solution in the preparation method of modified carbon black are 0.03 mol / L and 0.05 mol / L, respectively.

[0030] Comparative Example 1 The preparation method is basically the same as in Example 2, except that the modified carbon black is prepared by soaking 5 kg of carbon black in a 0.03 mol / L zinc chloride aqueous solution and stirring at 300 rpm for 3 h. Then, the insoluble matter is collected by filtration and dried at 120 °C for 8 h to obtain the precursor. The precursor is then calcined at 800 °C under a nitrogen atmosphere for 2 h. After the calcination, the carbon black is naturally cooled. The black solid is washed three times each with water and ethanol and then dried at 120 °C for 12 h to obtain the modified carbon black.

[0031] Comparative Example 2 The method is basically the same as Example 3, except that dodecyl dimethyl benzyl ammonium chloride is not added in step T1 of the method for preparing modified carbon black.

[0032] Comparative Example 3 The method is basically the same as Example 3, except that in step T1 of the modified carbon black preparation method, sodium dodecylbenzenesulfonate, an anionic surfactant, is used instead of dodecyl dimethyl benzyl ammonium chloride.

[0033] Comparative Example 4 The method is basically the same as Example 3, except that in step T1 of the modified carbon black preparation method, the nonionic surfactant polyethylene glycol 6000 is used instead of dodecyl dimethyl benzyl ammonium chloride.

[0034] Comparative Example 5 It is basically the same as Example 3, except that the modified carbon black is replaced with carbon black.

[0035] Test case The specific surface area of ​​the carbon black materials in the examples and comparative examples was tested using the BET specific surface area test method, and the results are shown in Table 1.

[0036] Table 1 Specific surface area test results The specific surface area of ​​untreated carbon black is 115.3 μm. 2 / g, as shown in Table 1, the specific surface area of ​​Comparative Example 1, which only underwent zinc ion immersion without intercalation treatment, showed the least significant increase. This may be due to the low zinc ion concentration and the weak etching effect of zinc on the carbon black matrix. Comparative Example 2 underwent intercalation treatment without surfactant followed by zinc ion immersion and calcination. Comparative Examples 3 and 4 used sodium dodecylbenzenesulfonate and polyethylene glycol 6000, respectively. It can be seen that intercalation treatment without surfactant did not significantly improve the specific surface area. The specific surface areas of Examples 1-4 were significantly higher than those of Comparative Examples 1-4, indicating that intercalation under the action of quaternary ammonium salt cationic surfactant had a better promoting effect. This is not only because it reduced the surface tension and strengthened the interaction between carbon black and n-pentadecanamine, but also because ammonium ions had a certain promoting effect on intercalation. Optimizing the intercalation uniformity effectively ensured the improvement of the interlayer spacing of the distorted layers of carbon black. Examples 2-4 showed that intercalation treatment followed by zinc ion immersion and calcination under the action of quaternary ammonium salt cationic surfactant could further improve the specific surface area, while the concentration of zinc ions should not be too high.

[0037] The properties of the TPE composite materials for elastic tubes prepared in the examples and comparative examples were tested. Specifically, the thermal conductivity was tested according to standard GB / T 3399-1982 "Test Method for Thermal Conductivity of Plastics - Heat-Protected Plate Method"; the compression recovery rate was tested according to standard GB / T 6342-1996 "Determination of Linear Dimensions of Foamed Plastics and Rubber"; and the tensile strength and elongation at break were tested according to standard GB / T 1040.2-2022 "Determination of Tensile Properties of Plastics - Part 2: Test Conditions for Molded and Extruded Plastics". The test results are shown in Table 2.

[0038] Table 2 Test Results Thermal conductivity W / (m·K) Compression recovery rate (%) Tensile strength (MPa) Elongation at break (%) Example 1 0.162 79.8 19.6 690 Example 2 0.211 81.5 21.2 730 Example 3 0.227 84.2 22.8 750 Example 4 0.205 80.7 20.4 710 Comparative Example 1 0.175 75.6 17.4 630 Comparative Example 2 0.183 77.4 18.2 650 Comparative Example 3 0.191 78.2 18.8 670 Comparative Example 4 0.196 78.7 19.3 690 Comparative Example 5 0.156 73.6 15.8 600 As can be seen from the test results in Table 2, the TPE composite material for elastic tubes prepared in the embodiments of the present invention has higher compression recovery rate, tensile strength, and elongation at break, indicating that the material has higher resilience and mechanical strength. This is because the carbon black material with a larger specific surface area is uniformly dispersed in the matrix, playing a good reinforcing role, while improving the interfacial bonding force and thus improving the resilience. Regarding the lower thermal conductivity of Example 1 compared to Examples 2-4 and Comparative Examples 1-4, this is because zinc is reduced to elemental zinc under high-temperature calcination, and zinc has a high thermal conductivity. The oxidized zinc oxide also has a higher thermal conductivity than the composite matrix and the carbon black. Simultaneously, the modified carbon black with a larger pore size is more easily dispersed in the composite matrix, forming an effective thermally conductive network and improving the thermal conductivity of the material.

[0039] The modified TPE materials prepared in the examples and comparative examples were also aged by irradiating them with 340nm ultraviolet light for 360h, and the compression recovery rate of the aged materials was tested. The results are shown in Table 3. Compression recovery rate (%) Example 1 69.3 Example 2 77.4 Example 3 81.6 Example 4 76.8 Comparative Example 1 70.2 Comparative Example 2 72.3 Comparative Example 3 73.9 Comparative Example 4 74.5 Comparative Example 5 62.3

[0040] As can be seen from the test results in Table 3, Examples 2-4 of the present invention exhibit good resistance to ultraviolet aging. This is because the introduction of zinc enhances the absorption capacity of ultraviolet light, and the carbon black matrix also acts as a good ultraviolet barrier. The carbon black with a large specific surface area is uniformly dispersed in the matrix and the zinc species on the surface play a good role in blocking ultraviolet light. In the absence of light stabilizer, the resistance to ultraviolet aging of the TPE composite material is significantly improved.

[0041] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A TPE composite material for elastic tubes, characterized in that, By weight, it includes 80-120 parts of styrene-based thermoplastic elastomer, 60-80 parts of white oil, 5-15 parts of polyolefin elastomer, 10-20 parts of rigid material, 10-30 parts of inorganic filler, 2-5 parts of lubricant, 2-5 parts of compatibilizer and 5-15 parts of modified carbon black; The method for preparing the modified carbon black includes, Modified carbon black is obtained by mixing carbon black, quaternary ammonium salt cationic surfactant, and fatty amine and then ultrasonically treating the mixture. The fatty amine is selected from straight-chain alkylamines with 12 to 18 carbon atoms; The rigid material includes at least one of polyethylene and polypropylene.

2. The TPE composite material for elastic tubes according to claim 1, characterized in that, The mass ratio of carbon black, quaternary ammonium salt cationic surfactant, and fatty amine is 2~10:0.2~0.5:50~100; The ultrasonic treatment was performed at 100-200W for 1-3 hours.

3. The TPE composite material for elastic tubes according to claim 1, characterized in that, After ultrasonic treatment, the obtained product is soaked in zinc ion solution and stirred for 2-5 hours to obtain a precursor; the precursor is then heat-treated to obtain modified carbon black.

4. The TPE composite material for elastic tubes according to claim 3, characterized in that, The concentration of the zinc ion solution is 0.01~0.05 mol / L; The heat treatment is carried out in a protective gas atmosphere at 600~900℃ for 1~5 hours.

5. The TPE composite material for elastic tubes according to claim 1, characterized in that, The inorganic filler includes at least one of titanium dioxide (2000-3000 mesh), calcium carbonate, barium sulfate, and talc.

6. The TPE composite material for elastic tubes according to claim 1, characterized in that, The lubricant includes at least one of stearic acid, magnesium stearate, zinc stearate, ethylene bis-stearamide, erucamide, paraffin wax, polypropylene wax, polyethylene wax, oleamide, and silicone.

7. The TPE composite material for elastic tubes according to claim 1, characterized in that, The compatibilizer includes at least one of maleic anhydride-grafted polypropylene, maleic anhydride-grafted styrene-ethylene-butene block copolymer, and vinylpyridine-grafted styrene-ethylene-butene block copolymer.

8. A method for preparing a TPE composite material for elastic tubes as described in any one of claims 1 to 7, characterized in that, include, A mixture is prepared by mixing styrene-based thermoplastic elastomers with white oil. The mixture is combined with polyolefin elastomer, rigid material, inorganic filler, lubricant, compatibilizer and modified carbon black and then extruded and granulated to obtain TPE composite material for elastic tubes.

9. The application of a TPE composite material for elastic tubes as described in any one of claims 1 to 7 in fitness equipment.

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