A method for preparing UV-resistant TPE thermoplastic elastomer material

Abstract

The present invention relates to the technical field of TPE elastomers, and discloses a method for preparing a UV-proof TPE thermoplastic elastomer material. The present invention blends hydrogenated styrene-butadiene-styrene block copolymer SEBS, polypropylene, polystyrene-based UV absorber, glycidyl methacrylate grafted polypropylene, and an antioxidant, and then adds them to a twin-screw extruder, melt-extrudes, and granulates to obtain a UV-proof TPE thermoplastic elastomer material. The polystyrene-based UV absorber of the present invention has good compatibility with SEBS in the elastomer material and polypropylene, so that the UV absorber is evenly dispersed in the elastomer material, which is beneficial to improving the tensile strength, elongation at break and hardness of the material. At the same time, the UV aging resistance of the elastomer material is improved.

Description

Technical Field

[0001] The invention relates to the technical field of TPE elastomers, in particular to a method for preparing an ultraviolet-proof TPE thermoplastic elastomer material. Background Art

[0002] TPE thermoplastic elastomer has the characteristics of traditional cross-linked vulcanized rubber and thermoplastic plastics, and has the advantages of high elasticity, good heat resistance, convenient processing, and various processing methods. It mainly includes styrene TPE, olefin TPE, diene TPE, etc. It is widely used in the fields of shoemaking industry, wires and cables, hoses and tapes, and plastic modification.

[0003] Patent CN105175977B discloses a low precipitation transparent TPE elastomer and its preparation method, and discloses that the TPE elastomer prepared by using SEBS, polypropylene-based elastomer, α-methylstyrene polymer, diacetyl epoxy vegetable oil acid glyceride, etc. as raw materials has the advantages of good demoulding effect, green environmental protection, health and safety, etc. Compared with the invention, the present invention adds a polystyrene-based ultraviolet absorber to the SEBS / polypropylene TPE thermoplastic elastomer material to avoid the influence of the ultraviolet absorber on the mechanical properties of the elastomer material, and at the same time enhances the mechanical strength and anti-ultraviolet aging performance of the material. Summary of the invention

[0004] (I) Technical problems to be solved: In view of the deficiencies in the prior art, the present invention provides a TPE thermoplastic elastomer material with good mechanical properties and UV protection.

[0005] (II) Technical solution: A method for preparing a UV-resistant TPE thermoplastic elastomer material, comprising the following steps:

[0006] (1) Add toluene into the flask, the structural formula is The benzotriazolyl styrene monomer is stirred and dissolved, and nitrogen is introduced. Azobisisobutyronitrile is added, and the mixture is stirred for reaction and then concentrated under reduced pressure. The mixture is washed with ethanol and dried to obtain a polystyrene-based ultraviolet absorber.

[0007] (2) Add hydrogenated styrene-butadiene-styrene block copolymer SEBS, polypropylene, polystyrene-based UV absorber, glycidyl methacrylate grafted polypropylene, and antioxidant into a high-speed mixer, add the materials into a twin-screw extruder after blending, melt-extrude, and granulate to obtain a UV-resistant TPE thermoplastic elastomer material.

[0008] Preferably, the reaction temperature in (1) is 70-80°C and the reaction time is 6-8h.

[0009] Preferably, in (1), the mass ratio of benzotriazolyl styrene monomer to azobisisobutyronitrile is 100:(0.5-0.6).

[0010] Preferably, in (2), the mass ratio of hydrogenated styrene-butadiene-styrene block copolymer SEBS, polypropylene, polystyrene-based UV absorber, and glycidyl methacrylate grafted polypropylene is (60-90):(10-40):(0.3-0.8):(0.02-0.06).

[0011] Preferably, in (2), during melt extrusion, the screw temperature is 195-205°C and the screw speed is 200-350 r / min.

[0012] Preferably, the preparation method of the benzotriazolyl styrene monomer is as follows: add ethanol, tetrahydrofuran or 1,4-dioxane solvent, 4-vinylbenzylamine, 2-(2'-hydroxy-3'-chloroacetylaminomethylene-5'-tert-butylphenyl)benzotriazole, and sodium carbonate in a mass ratio of (36-43):100:(28-40) to a flask, add water, heat to 50-80°C, stir to react for 5-12h, concentrate under reduced pressure, add water to dilute, add dichloromethane to extract, dry the dichloromethane extract with anhydrous sodium sulfate, filter, heat the filtrate to volatilize, cool in an ice water bath for recrystallization, and obtain the benzotriazolyl styrene monomer. The reaction formula is:

[0013]

[0014] (III) Technical effect: The present invention carries out a substitution reaction on 4-vinylbenzylamine and 2-(2'-hydroxy-3'-chloroacetamidomethyl-5'-tert-butylphenyl)benzotriazole to prepare a benzotriazole-based styrene monomer containing a styrene group and an active imino group, and then a self-polymerization reaction occurs in an azobisisobutyronitrile initiation system to obtain a polystyrene-based ultraviolet absorber.

[0015] The invention uses hydrogenated styrene-butadiene-styrene block copolymer and polypropylene as main components of TPE thermoplastic elastomer material, uses glycidyl methacrylate grafted polypropylene as a compatibilizer, and simultaneously adds a polystyrene-based ultraviolet absorber, and obtains the ultraviolet-proof TPE thermoplastic elastomer material through melt blending. The ultraviolet absorber contains a polystyrene structure with good mechanical properties, high strength and high modulus, and the ultraviolet absorber contains a polystyrene molecular chain, so it has good compatibility with the hydrogenated styrene-butadiene-styrene block copolymer SEBS. At the same time, the ultraviolet absorber contains active imino groups. In the process of melt blending and extrusion, the imino groups can react with the epoxy groups of glycidyl methacrylate grafted polypropylene, so that the glycidyl methacrylate grafted polypropylene can play the role of a compatibilizer, improve the compatibility between the ultraviolet absorber and the polypropylene component in the elastomer material, so that the polystyrene-based ultraviolet absorber has good compatibility with the SEBS in the elastomer material and the polypropylene, so that the ultraviolet absorber is evenly dispersed in the elastomer material, which is beneficial to improving the tensile strength, elongation at break and hardness of the material.

[0016] The polystyrene-based ultraviolet absorber of the present invention contains 2'-hydroxyphenylbenzotriazole anti-ultraviolet absorption groups, which can convert light energy into heat energy and release it by proton transfer, thereby significantly improving the anti-ultraviolet aging performance of the elastomeric material. After the ultraviolet light accelerated aging sample, the elastomeric material still has very high tensile strength, elongation at break and hardness. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and are not used to limit the invention.

[0018] The preparation method of 2g 2-(2'-hydroxy-3'-chloroacetylaminomethylene-5'-tert-butylphenyl)benzotriazole is as follows: 138g of concentrated sulfuric acid (mass fraction 98%), 33.4g of 2-(2'-hydroxy-5-tert-butylphenyl)benzotriazole, and 19.3g of N-hydroxymethylchloroacetamide are added to a flask, and the mixture is stirred at 25°C for 3h. After the reaction, the solution is added dropwise to ice water, stirred and allowed to stand, filtered, washed with water, and dried to obtain 2-(2'-hydroxy-3'-chloroacetylaminomethylene-5'-tert-butylphenyl)benzotriazole. The reaction formula is:

[0019]

[0020] The preparation method of glycidyl methacrylate grafted polypropylene is as follows: 50g of polypropylene, 3g of glycidyl methacrylate, and 0.26g of dibenzoyl peroxide are added to a torque rheometer, melt-grafted at 180°C for 6 minutes, the product is added to xylene, heated and stirred to dissolve, and then acetone is added for precipitation. After filtering, the product is placed in a Soxhlet extractor, extracted with acetone, and dried to obtain glycidyl methacrylate grafted polypropylene.

[0021] Example 1

[0022] (1) Add 30 mL of 1,4-dioxane solvent, 0.78 g of 4-vinylbenzylamine, 2 g of 2-(2'-hydroxy-3'-chloroacetamidomethyl-5'-tert-butylphenyl)benzotriazole, and 0.8 g of sodium carbonate to a flask, add 5 mL of water, heat to 80° C., stir and react for 5 h, concentrate under reduced pressure, add water to dilute, add dichloromethane to extract, dry the dichloromethane extract with anhydrous sodium sulfate, filter, heat the filtrate to evaporate, cool in an ice water bath and recrystallize to obtain a benzotriazole-based styrene monomer.

[0023] (2) Add 40 mL of toluene and 5 g of benzotriazolyl styrene monomer into a flask, stir to dissolve, then introduce nitrogen, add 25 mg of azobisisobutyronitrile, heat to 80° C., stir to react for 6 h, concentrate under reduced pressure, wash with ethanol, and dry to obtain a polystyrene-based UV absorber.

[0024] (3) Add 900 g of hydrogenated styrene-butadiene-styrene block copolymer SEBS, 100 g of polypropylene, 3 g of polystyrene-based UV absorber, 0.2 g of glycidyl methacrylate grafted polypropylene, and 0.4 g of antioxidant 1010 to a high-speed mixer, and after blending, add the materials to a twin-screw extruder for melt extrusion. During the melt extrusion, the screw temperature is 195° C. and the screw speed is 250 r / min. Granulation is performed to obtain a UV-resistant TPE thermoplastic elastomer material.

[0025] Example 2

[0026] (1) Add 25 mL of tetrahydrofuran solvent, 0.72 g of 4-vinylbenzylamine, 2 g of 2-(2'-hydroxy-3'-chloroacetamidomethyl-5'-tert-butylphenyl)benzotriazole, and 0.56 g of sodium carbonate to a flask, add 4 mL of water, heat to 50° C., stir to react for 12 h, concentrate under reduced pressure, add water to dilute, add dichloromethane to extract, dry the dichloromethane extract with anhydrous sodium sulfate, filter, heat the filtrate to evaporate, cool in an ice-water bath for recrystallization, and obtain a benzotriazolyl styrene monomer.

[0027] (2) Add 50 mL of toluene and 5 g of benzotriazolyl styrene monomer into a flask, stir to dissolve, then introduce nitrogen, add 30 mg of azobisisobutyronitrile, heat to 70° C., stir to react for 6 h, concentrate under reduced pressure, wash with ethanol, and dry to obtain a polystyrene-based UV absorber.

[0028] (3) Add 800 g of hydrogenated styrene-butadiene-styrene block copolymer SEBS, 200 g of polypropylene, 4.5 g of polystyrene-based UV absorber, 0.3 g of glycidyl methacrylate grafted polypropylene, and 0.4 g of antioxidant 1010 to a high-speed mixer, and after blending, add the materials to a twin-screw extruder for melt extrusion. During the melt extrusion, the screw temperature is 200° C. and the screw speed is 350 r / min. Granulation is performed to obtain a UV-resistant TPE thermoplastic elastomer material.

[0029] Example 3

[0030] (1) Add 30 mL of 1,4-dioxane solvent, 0.72 g of 4-vinylbenzylamine, 2 g of 2-(2'-hydroxy-3'-chloroacetamidomethyl-5'-tert-butylphenyl)benzotriazole, and 0.68 g of sodium carbonate to a flask, add 5 mL of water, heat to 80° C., stir and react for 5 h, concentrate under reduced pressure, add water to dilute, add dichloromethane to extract, dry the dichloromethane extract with anhydrous sodium sulfate, filter, heat the filtrate to evaporate, cool in an ice water bath and recrystallize to obtain a benzotriazole-based styrene monomer.

[0031] (2) Add 50 mL of toluene and 5 g of benzotriazolyl styrene monomer into a flask, stir to dissolve, then introduce nitrogen, add 30 mg of azobisisobutyronitrile, heat to 75° C., stir to react for 8 h, concentrate under reduced pressure, wash with ethanol, and dry to obtain a polystyrene-based UV absorber.

[0032] (3) Add 700 g of hydrogenated styrene-butadiene-styrene block copolymer SEBS, 300 g of polypropylene, 6 g of polystyrene-based UV absorber, 0.45 g of glycidyl methacrylate grafted polypropylene, and 0.4 g of antioxidant 1010 to a high-speed mixer, and after blending, add the materials to a twin-screw extruder for melt extrusion. During the melt extrusion, the screw temperature is 205° C. and the screw speed is 200 r / min. Granulation is performed to obtain a UV-resistant TPE thermoplastic elastomer material.

[0033] Example 4

[0034] (1) Add 30 mL of ethanol solvent, 0.86 g of 4-vinylbenzylamine, 2 g of 2-(2'-hydroxy-3'-chloroacetylaminomethylene-5'-tert-butylphenyl)benzotriazole, and 0.56 g of sodium carbonate to a flask, add 3 mL of water, heat to 70° C., stir to react for 12 h, concentrate under reduced pressure, add water to dilute, add dichloromethane to extract, dry the dichloromethane extract with anhydrous sodium sulfate, filter, heat the filtrate to evaporate, cool in an ice water bath for recrystallization, and obtain a benzotriazole-based styrene monomer.

[0035] (2) Add 50 mL of toluene and 5 g of benzotriazolyl styrene monomer into a flask, stir to dissolve, then introduce nitrogen, add 28 mg of azobisisobutyronitrile, heat to 80° C., stir to react for 6 h, concentrate under reduced pressure, wash with ethanol, and dry to obtain a polystyrene-based UV absorber.

[0036] (3) Add 600 g of hydrogenated styrene-butadiene-styrene block copolymer SEBS, 400 g of polypropylene, 8 g of polystyrene-based UV absorber, 0.6 g of glycidyl methacrylate grafted polypropylene, and 0.4 g of antioxidant 1010 to a high-speed mixer, and after blending, add the materials to a twin-screw extruder for melt extrusion. During the melt extrusion, the screw temperature is 200° C. and the screw speed is 200 r / min. Granulation is performed to obtain a UV-resistant TPE thermoplastic elastomer material.

[0037] Comparative Example 1

[0038] (1) Add 900 g of hydrogenated styrene-butadiene-styrene block copolymer SEBS, 100 g of polypropylene, 0.2 g of glycidyl methacrylate grafted polypropylene, and 0.4 g of antioxidant 1010 into a high-speed mixer, blend and add the materials into a twin-screw extruder for melt extrusion. During the melt extrusion, the screw temperature is 195° C. and the screw speed is 250 r / min. Granulation is performed to obtain a UV-resistant TPE thermoplastic elastomer material.

[0039] Comparative Example 2

[0040] (1) Add 30 mL of 1,4-dioxane solvent, 0.78 g of 4-vinylbenzylamine, 2 g of 2-(2'-hydroxy-3'-chloroacetamidomethyl-5'-tert-butylphenyl)benzotriazole, and 0.8 g of sodium carbonate to a flask, add 5 mL of water, heat to 80° C., stir and react for 5 h, concentrate under reduced pressure, add water to dilute, add dichloromethane to extract, dry the dichloromethane extract with anhydrous sodium sulfate, filter, heat the filtrate to evaporate, cool in an ice water bath and recrystallize to obtain a benzotriazolyl styrene monomer.

[0041] (2) Add 900 g of hydrogenated styrene-butadiene-styrene block copolymer SEBS, 100 g of polypropylene, 3 g of benzotriazole-based styrene monomer, 0.2 g of glycidyl methacrylate grafted polypropylene, and 0.4 g of antioxidant 1010 to a high-speed mixer, and after blending, add the materials to a twin-screw extruder for melt extrusion. During the melt extrusion, the screw temperature is 195° C. and the screw speed is 250 r / min. Granulation is performed to obtain a UV-resistant TPE thermoplastic elastomer material.

[0042] Comparative Example 3

[0043] (1) Add 30 mL of 1,4-dioxane solvent, 0.78 g of 4-vinylbenzylamine, 2 g of 2-(2'-hydroxy-3'-chloroacetamidomethyl-5'-tert-butylphenyl)benzotriazole, and 0.8 g of sodium carbonate to a flask, add 5 mL of water, heat to 80° C., stir and react for 5 h, concentrate under reduced pressure, add water to dilute, add dichloromethane to extract, dry the dichloromethane extract with anhydrous sodium sulfate, filter, heat the filtrate to evaporate, cool in an ice water bath and recrystallize to obtain a benzotriazolyl styrene monomer.

[0044] (2) Add 40 mL of toluene and 5 g of benzotriazolyl styrene monomer into a flask, stir to dissolve, then introduce nitrogen, add 25 mg of azobisisobutyronitrile, heat to 80° C., stir to react for 6 h, concentrate under reduced pressure, wash with ethanol, and dry to obtain a polystyrene-based UV absorber.

[0045] (3) Add 900 g of hydrogenated styrene-butadiene-styrene block copolymer SEBS, 100 g of polypropylene, 3 g of polystyrene-based UV absorber, and 0.4 g of antioxidant 1010 to a high-speed mixer, add the materials to a twin-screw extruder after blending, and melt extrude the materials. During the melt extrusion, the screw temperature is 195° C. and the screw speed is 250 r / min. Granulation is performed to obtain a UV-resistant TPE thermoplastic elastomer material.

[0046] The UV-resistant TPE thermoplastic elastomer material was made into test specimens by an injection molding machine at an injection molding temperature of 200°C.

[0047] The tensile properties of the samples were tested according to GB / T528-2009 method.

[0048] The hardness of the sample was tested according to GB / T531.1-2008 method.

[0049] The test sample was placed in a UV accelerated aging tester for 240 hours of UV aging. The wavelength of the UV lamp was 340nm and the radiation intensity was 0.74W / m 2 , relative humidity is 40%, and the temperature of the test chamber is 60℃. Then the tensile properties and hardness are tested. The effect test is shown in Table 1-3.

[0050] Table 1: Tensile strength and retention rate before and after aging

[0051]

[0052] Table 2: Elongation at break and retention before and after aging

[0053]

[0054]

[0055] Table 3: Shore A hardness and retention rate before and after aging

[0056]

[0057] After testing, compared with Comparative Example 1, the polystyrene-based ultraviolet absorber is added to the thermoplastic elastomer material of Example 1. Before irradiation, the tensile strength, elongation at break and hardness of the elastomer material are improved to a certain extent. This is mainly because the ultraviolet absorber contains a polystyrene structure with good mechanical properties, high strength and high modulus, and the polystyrene molecular chain contained in the ultraviolet absorber has good compatibility with the hydrogenated styrene-butadiene-styrene block copolymer SEBS. At the same time, the ultraviolet absorber contains active imino groups. During the melt blending and extrusion process, the imino groups can react with the epoxy groups of glycidyl methacrylate grafted polypropylene, so that the glycidyl methacrylate grafted polypropylene can play the role of a compatibilizer, improve the compatibility between the ultraviolet absorber and the polypropylene component in the elastomer material, so that the polystyrene-based ultraviolet absorber has good compatibility with the SEBS in the elastomer material and the polypropylene. The ultraviolet absorber is evenly dispersed in the elastomer material, which is beneficial to improving the tensile strength, elongation at break and hardness of the material. In addition, the polystyrene-based UV absorber contains 2'-hydroxyphenylbenzotriazole anti-UV absorption groups, which can convert the energy of light into heat energy and release it through proton transfer, significantly improving the anti-UV aging performance of the elastomeric material. After the accelerated UV aging test specimen, the elastomeric material still has high tensile strength, elongation at break and hardness.

[0058] Comparative Example 1 does not add anti-ultraviolet absorber. After the ultraviolet light accelerated aging test, the tensile strength, elongation at break and hardness of the elastomeric material decrease significantly, and the retention rate is low.

[0059] Compared with Comparative Example 1, Comparative Example 2 adds benzotriazolyl styrene monomer, which has poor compatibility with SEBS and polypropylene. After blending, the tensile strength, elongation at break and hardness of the elastomeric material before ultraviolet irradiation tend to decrease.

[0060] Compared with Example 1, Comparative Example 3 does not add glycidyl methacrylate grafted polypropylene. Although the compatibility between the polystyrene-based UV absorber added in Comparative Example 3 and SEBS is poor, the compatibility between the UV absorber and polypropylene is poor, resulting in the compatibility and dispersibility of the UV absorber with the elastomeric material being lower than that in Example 1, and the tensile strength, elongation at break and hardness before UV irradiation are lower than those in Example 1.

[0061] The above description is a preferred embodiment of the invention and is not intended to limit the invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the invention should be included in the protection scope of the invention.

Claims

1. A method for preparing a UV-resistant TPE thermoplastic elastomer material, characterized in that: The preparation method comprises the following steps: (1) Add toluene into the flask, the structural formula is The benzotriazolyl styrene monomer is stirred and dissolved, and nitrogen is introduced, and azobisisobutyronitrile is added, and the mixture is stirred and reacted, and then concentrated under reduced pressure, washed with ethanol, and dried to obtain a polystyrene-based ultraviolet absorber; (2) Add hydrogenated styrene-butadiene-styrene block copolymer SEBS, polypropylene, polystyrene-based UV absorber, glycidyl methacrylate grafted polypropylene, and antioxidant into a high-speed mixer, add the materials into a twin-screw extruder after blending, melt-extrude, and granulate to obtain a UV-resistant TPE thermoplastic elastomer material.

2. The method for preparing the UV-resistant TPE thermoplastic elastomer material according to claim 1, characterized in that: The reaction temperature in (1) is 70-80°C and the reaction time is 6-8h.

3. The method for preparing the UV-resistant TPE thermoplastic elastomer material according to claim 1, characterized in that: In the above (1), the mass ratio of benzotriazolyl styrene monomer to azobisisobutyronitrile is 100:(0.5-0.6).

4. The method for preparing the UV-resistant TPE thermoplastic elastomer material according to claim 1, characterized in that: In the above (2), the mass ratio of hydrogenated styrene-butadiene-styrene block copolymer SEBS, polypropylene, polystyrene-based UV absorber, and glycidyl methacrylate grafted polypropylene is (60-90):(10-40):(0.3-0.8):(0.02-0.06).

5. The method for preparing the UV-resistant TPE thermoplastic elastomer material according to claim 1, characterized in that: In the above (2), during melt extrusion, the screw temperature is 195-205°C and the screw speed is 200-350 r / min.

6. The method for preparing the UV-resistant TPE thermoplastic elastomer material according to claim 1, characterized in that: The preparation method of the benzotriazolyl styrene monomer is as follows: adding a solvent and 4-vinylbenzylamine, the structural formula of which is 2-(2'-hydroxy-3'-chloroacetamidomethyl-5'-tert-butylphenyl)benzotriazole, sodium carbonate, water, stirred for reaction, concentrated under reduced pressure, diluted with water, extracted with dichloromethane, dried with anhydrous sodium sulfate, filtered, heated and volatilized the filtrate, cooled in an ice-water bath and recrystallized to obtain benzotriazole-based styrene monomer.

7. The method for preparing the UV-resistant TPE thermoplastic elastomer material according to claim 6, characterized in that: The solvent is ethanol, tetrahydrofuran or 1,4-dioxane.

8. The method for preparing the UV-resistant TPE thermoplastic elastomer material according to claim 6, characterized in that: The mass ratio of the 4-vinylbenzylamine, 2-(2'-hydroxy-3'-chloroacetamidomethyl-5'-tert-butylphenyl)benzotriazole and sodium carbonate is (36-43):100:(28-40).

9. The method for preparing the UV-resistant TPE thermoplastic elastomer material according to claim 6, characterized in that: In the method for preparing the benzotriazolyl styrene monomer, the reaction temperature is 50-80° C. and the reaction time is 5-12 hours.

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