Thermoplastic elastomer composite material, method for preparing same, and use thereof

Abstract

This invention relates to a thermoplastic elastomer composite material, its preparation method, and its applications. The thermoplastic elastomer composite material comprises the following components in parts by weight: 10-30 parts of hydrogenated styrene elastomer, 20-60 parts of softening oil, 5-15 parts of polypropylene, 4-16 parts of thermoplastic polyester elastomer, 3-11 parts of ethylene-vinyl acetate copolymer, 5-15 parts of maleic anhydride-grafted polypropylene, and maleic anhydride-grafted olefin copolymer elastomer. The thermoplastic elastomer composite material of this invention not only possesses good tensile strength and good adhesion strength to nylon at room temperature, but also good adhesion strength to nylon at low temperatures, making it highly suitable as a coating material for nylon in cold-weather applications.

Description

Technical Field

[0001] This invention relates to the field of polymer material modification technology, and more specifically, to a thermoplastic elastomer composite material, its preparation method, and its application. Background Technology

[0002] Thermoplastic elastomer (TPE) is a material that combines the high elasticity, high strength, and high resilience of rubber with the characteristics of injection molding. TPE boasts numerous advantages, including being environmentally friendly, non-toxic, safe, having a wide hardness range, excellent colorability, a soft touch, weather resistance, fatigue resistance, temperature resistance, superior processing performance, and requiring no vulcanization. Therefore, as a novel, multifunctional, and environmentally friendly material, TPE has a very broad application market.

[0003] One important application of TPE materials is as overmolding materials, which involves overmolding TPE onto other materials. Nylon is a widely used engineering plastic with advantages such as high mechanical strength, good heat resistance, and good abrasion resistance. In recent years, nylon has been widely used in toys, daily necessities, and industrial products. Products made of nylon often have a hard and smooth surface, resulting in a poor feel during use and a tendency to slip. To solve this problem, a layer of TPE material can be coated onto the nylon surface, giving it a better feel, increasing user comfort, and greatly improving the product's aesthetics. For example, a Chinese patent, "A Nylon-Coated TPE Composite Material, Its Preparation Method, and Its Application," provides a TPE composite material coated with nylon.

[0004] Because nylon products have a wide range of applications, the TPE materials used as overmolding materials for nylon must also be able to adapt to the operating environment of nylon products. In northern my country, especially in the Northeast, Inner Mongolia, and Xinjiang Uygur Autonomous Region, outdoor temperatures in winter often reach around -30℃. When the natural environment is at -30℃, common TPE materials become stiff and hard, lose elasticity, and are prone to detaching from the bonded nylon, affecting the performance of the nylon products. Summary of the Invention

[0005] The primary objective of this invention is to overcome the problem of poor low-temperature performance of existing TPE materials used for nylon overmolding, and to provide a thermoplastic elastomer composite material.

[0006] A further object of the present invention is to provide a method for preparing the above-mentioned thermoplastic elastomer composite material.

[0007] A further object of the present invention is to provide the application of the above-mentioned thermoplastic elastomer composite material in the preparation of overcoating materials for nylon products.

[0008] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0009] A thermoplastic elastomer composite material comprising the following components in parts by weight:

[0010] 10-30 parts of hydrogenated styrene elastomer

[0011] 20-60 parts softening oil

[0012] 5-15 parts of polypropylene

[0013] 4-16 parts of thermoplastic polyester elastomer,

[0014] 3 to 11 parts of ethylene-vinyl acetate copolymer

[0015] 5-15 parts of maleic anhydride-grafted polypropylene.

[0016] 5-15 parts of maleic anhydride-grafted olefin copolymer elastomer;

[0017] The VA (vinyl acetate unit) content in the ethylene-vinyl acetate copolymer is 9-30 wt%.

[0018] The softened oil has a kinematic viscosity ≥85 mmHg at 40°C. 2 / s.

[0019] In this invention, the addition of polypropylene can provide the material with a certain mechanical strength; the addition of maleic anhydride-grafted polypropylene can improve the compatibility between components and help improve the mechanical strength and bonding performance of thermoplastic elastomer composites.

[0020] Thermoplastic polyester elastomers have good low-temperature resistance, but their compatibility with hydrogenated styrene elastomers is poor, especially at low temperatures, where they are prone to separation. This means that thermoplastic polyester elastomers cannot effectively impart low-temperature resistance to thermoplastic elastomer composites based on hydrogenated styrene elastomers.

[0021] The inventors of this invention discovered that controlling the viscosity of softening oil within a certain range allows for good compatibility between hydrogenated styrene elastomers and thermoplastic polyester elastomers during processing. Building upon this, the addition of maleic anhydride-grafted olefin copolymer elastomers, characterized by low crystallization and slow cooling, not only increases the material's toughness but also acts as a compatibilizer, improving the dispersibility of thermoplastic polyester elastomers in thermoplastic elastomer composites at low temperatures. Further addition of ethylene-vinyl acetate copolymers with a specific VA content further enhances the compatibility between thermoplastic polyester elastomers and hydrogenated styrene elastomers. The combined effect of these three components endows thermoplastic polyester elastomers with excellent low-temperature resistance in thermoplastic elastomer composites, exhibiting good adhesive strength to nylon at low temperatures.

[0022] In addition, the combined effects of softening oil of specific viscosity, maleic anhydride grafted olefin copolymer elastomer, and ethylene-vinyl acetate copolymer with specific VA content improve the compatibility of the material, which in turn enhances the tensile strength of thermoplastic elastomer composites.

[0023] In this invention, the amount of hydrogenated styrene elastomer used can be 10, 12, 15, 18, 20, 22, 25, 27, or 30 parts by weight. The amount of softening oil used can be 20, 23, 25, 28, 30, 33, 35, 38, 40, 42, 45, 48, 50, 52, 55, 58, or 60 parts by weight. The amount of polypropylene used can be 5, 7, 9, 11, 13, or 15 parts by weight. The amount of thermoplastic polyester elastomer used can be 4, 5, 6, 8, 10, 12, 14, 15, or 16 parts by weight. The amount of ethylene-vinyl acetate copolymer used can be 3, 4, 6, 8, 10, or 11 parts by weight. The amount of maleic anhydride-grafted polypropylene used can be 5, 7, 9, 11, 13, or 15 parts by weight. The specific amount of maleic anhydride-grafted olefin copolymer elastomer used can be 5, 7, 9, 11, 13 or 15 parts by weight.

[0024] In this invention, the VA content in the ethylene-vinyl acetate copolymer can specifically be 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 20wt%, 22wt%, 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, or 30wt%. The VA content in the ethylene-vinyl acetate copolymer can be determined by titration.

[0025] In this invention, the kinematic viscosity of the softened oil at 40°C can specifically be 85, 88, 90, 95, 100, 110, 120, 130, 140, 145, or 150 mm⁻¹. 2 / s. The kinematic viscosity of softened oil can be determined according to standard ASTM D455-2015.

[0026] In this invention, hydrogenated styrene elastomer is used as the main resin, and its content is at least 10 wt% of the thermoplastic elastomer composite material.

[0027] Preferably, the hydrogenated styrene elastomer is at least one of hydrogenated styrene-butadiene block copolymer or hydrogenated styrene-isoprene block copolymer.

[0028] Preferably, the viscosity of the hydrogenated styrene elastomer, measured at 25°C, with toluene as the solvent and a styrene elastomer concentration of 10 wt%, is 350–2500 cp.

[0029] In this invention, the viscosity of the hydrogenated styrene elastomer can be measured according to Q / SH1085 130-2006.

[0030] Preferably, the softened oil has a kinematic viscosity ≥90 mmHg at 40°C. 2 / s.

[0031] More preferably, the softened oil has a kinematic viscosity of 90–150 mmHg at 40°C. 2 / s.

[0032] More preferably, the softened oil has a kinematic viscosity of 120–135 mmHg at 40°C. 2 / s.

[0033] Preferably, the softening oil is a mineral oil; the mineral oil includes, but is not limited to, cycloalkane oil.

[0034] Preferably, the polypropylene is at least one of homopolymer polypropylene or copolymer polypropylene.

[0035] More preferably, the copolymer polypropylene is at least one of block copolymer polypropylene or random copolymer polypropylene.

[0036] More preferably, the copolymer polypropylene is a copolymer of propylene and ethylene.

[0037] More preferably, the polypropylene is random copolymer polypropylene. Random copolymer polypropylene has lower crystallinity, which allows for better adhesion strength of the thermoplastic elastomer composite material to nylon at both room temperature and low temperatures.

[0038] Preferably, the melt flow rate of the polypropylene measured at 190°C and 2.16 kg is 10–20 g / 10 min.

[0039] In this invention, the melt flow rate of polypropylene can be measured according to ISO 1133:2022.

[0040] Preferably, the hard segment of the thermoplastic polyester elastomer is polyester, and the soft segment is aliphatic polyester and / or polyether.

[0041] More preferably, the hard segment is polybutylene terephthalate (PBT).

[0042] Preferably, the Shore hardness D of the thermoplastic polyester elastomer is 35 to 72.

[0043] In this invention, the Shore hardness D of the thermoplastic polyester elastomer can be measured according to standard ISO 7619-1-2004.

[0044] Preferably, the maleic anhydride grafting rate in the maleic anhydride-grafted polypropylene is 0.5–1.5 wt%. The maleic anhydride grafting rate can be determined by chemical titration (KOH-ethanol solution).

[0045] Preferably, the maleic anhydride grafting rate in the maleic anhydride-grafted olefin copolymer elastomer is 0.4–1.2 wt%. The maleic anhydride grafting rate can be determined by chemical titration (KOH-ethanol solution).

[0046] Preferably, the maleic anhydride-grafted olefin copolymer elastomer is at least one of maleic anhydride-grafted ethylene-propylene copolymer elastomer or maleic anhydride-grafted ethylene-octene copolymer elastomer.

[0047] More preferably, the ethylene content in the maleic anhydride-grafted olefin copolymer elastomer is 60-86 wt%.

[0048] The thermoplastic elastomer composite material of the present invention can also be supplemented with 0 to 50 parts of filler according to the actual needs of the product. The filler is at least one selected from silica, wollastonite, calcium carbonate, glass microspheres, talc, kaolin, diatomaceous earth, barium sulfate, or mica.

[0049] Preferably, the thermoplastic elastomer composite material further includes 0 to 2 parts of other additives.

[0050] More preferably, the other additives are at least one of antioxidants, light stabilizers, or lubricants.

[0051] More preferably, the antioxidant is at least one of 2,6-di-tert-butyl-4-methylphenol, antioxidant 1010, antioxidant 1076, antioxidant 1790, antioxidant 168, or antioxidant 626.

[0052] More preferably, the light stabilizer is at least one of hindered amine light stabilizers or triazine light stabilizers.

[0053] More preferably, the hindered amine light stabilizer can be at least one of light stabilizer 622, light stabilizer 770, light stabilizer 944, light stabilizer 783, light stabilizer 791, light stabilizer 3853, light stabilizer 292 or light stabilizer 123; and the triazine light stabilizer can be at least one of UV-234, UV-236 or UV-2373.

[0054] More preferably, the lubricant is at least one of vinyl bis-stearamide, hydroxy fatty acid lubricant, erucamide, zinc stearate, magnesium stearate, or polyethylene wax.

[0055] The preparation method of the above-mentioned thermoplastic elastomer composite material includes the following steps: first, mixing hydrogenated styrene elastomer and softening oil, then mixing with the remaining components, melt extruding, and granulating to obtain the thermoplastic elastomer composite material.

[0056] Preferably, the temperature of the melt extrusion is 80–220°C.

[0057] Preferably, the screw speed of the melt extrusion extruder is 300-500 r / min; the length-to-diameter ratio of the screw is 20-30:1.

[0058] The application of the above-mentioned thermoplastic elastomer composite material in the preparation of overcoating materials for nylon products is also within the scope of protection of this invention.

[0059] Preferably, the nylon product is a product used at low temperatures; the low temperature is -30 to -40°C.

[0060] Compared with the prior art, the beneficial effects of the present invention are:

[0061] The thermoplastic elastomer composite material of the present invention not only has good tensile strength and good adhesion strength to nylon at room temperature, but also has good adhesion strength to nylon at low temperature, making it very suitable as a coating material for nylon in cold application scenarios. Detailed Implementation

[0062] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0063] The reagents used in the various embodiments and comparative examples of this invention are described below:

[0064] Hydrogenated styrene elastomer 1#: Hydrogenated styrene-butadiene block copolymer, SEBS 7551, produced by Lee Chang Yung (Taiwan), viscosity 2000 cp;

[0065] Hydrogenated styrene elastomer #2: Hydrogenated styrene-butadiene block copolymer, SEBS6552, Zhejiang Zhongli, viscosity 370cp;

[0066] Softening oil #1: Naphthenic oil, 650SN, Shanghai Daopu, kinematic viscosity at 40℃ is 120-135 mmHg. 2 / s;

[0067] Softening oil #2: Naphthenic oil, 500SN, Beiran Industry, kinematic viscosity at 40℃ is 96 mmHg. 2 / s;

[0068] Softening oil #3: Naphthenic oil, 350SN, Shanghai Daopu, kinematic viscosity at 40℃ is 65-72 mmHg. 2 / s;

[0069] Polypropylene 1#: Random copolymer polypropylene, grade PP RJ766MO, manufacturer Bolu Chemical;

[0070] Polypropylene 2#: Block copolymer polypropylene, grade PP K7100, manufacturer Yanshan Petrochemical;

[0071] Polypropylene 3#: Homopolymer polypropylene, grade PP HP-500N, manufacturer: Basel;

[0072] Thermoplastic polyester elastomer 1#: DH600, Shin Kong Pharmaceutical Co., Ltd., Taiwan, China, with a hardness of 60D;

[0073] Thermoplastic polyester elastomer #2: DH400, Shin Kong Pharmaceutical Industries Co., Ltd., Taiwan, China, with a hardness of 40D;

[0074] Thermoplastic polyurethane elastomer: Desmopan 385E, Covestro;

[0075] Ethylene-vinyl acetate copolymer 1#: VA content 22wt%, UE631, polymerization chemicals;

[0076] Ethylene-vinyl acetate copolymer #2: VA content 10wt%, UE510, polymer chemicals;

[0077] Ethylene-vinyl acetate copolymer #3: VA content 8wt%, UE508, polymerization chemicals;

[0078] Ethylene-vinyl acetate copolymer #4: VA content 37wt%, P3307, Mitsui, Japan;

[0079] Ethylene-acrylic acid copolymer; DuPont, 5900I, acrylic acid content 20wt%;

[0080] Maleic anhydride-grafted polypropylene: AD-10, Nanhai Baichen Polymer;

[0081] Maleic anhydride-grafted olefin copolymer elastomer 1#: FB521A, maleic anhydride-grafted ethylene octene copolymer, Jia Yi Rong;

[0082] Maleic anhydride-grafted olefin copolymer elastomer 2#: CMG5805, maleic anhydride-grafted ethylene octene copolymer, Jia Yi Rong;

[0083] Other additives #1: Antioxidant 1010 and Antioxidant 168 are mixed in a mass ratio of 2:1. Both Antioxidant 1010 and Antioxidant 168 are commercially available.

[0084] Other additives #2: Light stabilizer, Cyasorb UV-3808pps, Cypermethrin;

[0085] Unless otherwise specified, all components used in the parallel examples and comparative examples (e.g., other additives 1# and other additives 2#) are the same commercially available products.

[0086] The thermoplastic elastomer composite materials provided in the embodiments and comparative examples of the present invention were subjected to performance testing according to the following test methods:

[0087] (1) Tensile strength test method: Tested according to ISO527-2012 standard. After injection molding into a standard square plate of 2*100*100mm, cut into type 2 strips with a cutter. After being placed at room temperature for 24 hours, the tensile test was performed. The molding cycle is based on the cycle of injection molding tensile strips.

[0088] (2) Adhesion strength test methods: including adhesion strength at room temperature and adhesion strength at low temperature. Adhesion strength at room temperature: According to GB / T 7760-2003 standard, the thermoplastic elastomer composite material to be tested is injected onto a PA substrate sample using an injection molding machine on a specific mold at an injection temperature of 255℃. After being placed at room temperature (25℃) for 24 hours, a 90° peel is performed to test the adhesion strength between the thermoplastic elastomer composite material and the PA substrate sample. Adhesion strength at low temperature: After the sample is injection molded into a standard 2*100*100mm square plate and then covered with a PA substrate, it is placed at -35℃ for 8 hours before testing its adhesion strength. Generally, a peel force ≥ 2.0 N / mm is considered usable.

[0089] The thermoplastic elastomer composite materials provided in the embodiments and comparative examples of the present invention were prepared by the following method:

[0090] 1) Weigh each component according to the formula, mix the styrene elastomer and softening oil evenly to obtain a premix, and let it stand for more than 24 hours.

[0091] 2) The premix is ​​mixed with other components and then fed into a twin-screw extruder from the main feeder. After melt extrusion and granulation, a thermoplastic elastomer composite material is obtained. The twin-screw extruder has a screw length-to-diameter ratio of 26:1, a screw speed of 450 r / min, and melt temperature zones of 80℃, 120℃, 190℃, 200℃, 200℃, 200℃, 200℃, 200℃, 200℃, and 210℃.

[0092] Examples 1-10

[0093] Examples 1-10 provide a series of thermoplastic elastomer composite materials, the formulations of which are shown in Table 1.

[0094] Table 1. Formulations (parts by weight) for Examples 1-10

[0095]

[0096]

[0097] Comparative Examples 1-8

[0098] Comparative Examples 1–8 provide a series of thermoplastic elastomer composite materials, the formulations of which are shown in Table 2.

[0099] Table 2 shows the formulations (parts by weight) for Comparative Examples 1–8.

[0100]

[0101] The properties of the thermoplastic elastomer composite materials of each embodiment and comparative example were determined according to the test methods mentioned above, and the test results are shown in Table 3.

[0102] Table 3. Performance results of thermoplastic elastomer composite materials in each embodiment and comparative example.

[0103]

[0104]

[0105] As can be seen from Table 3:

[0106] The tensile strength of the thermoplastic elastomer composite materials in Examples 1 to 10 is all above 5.0 MPa, the room temperature bonding strength is all above 3.3 N / mm, and the low temperature bonding strength is all above 2.6 N / mm. This shows that the present invention not only has good tensile strength and good bonding strength to nylon at room temperature, but also good bonding strength to nylon at low temperature, making it very suitable as a nylon overmolding material for cold application scenarios.

[0107] In Comparative Example 1, the viscosity of the softening oil used was too low, resulting in poor compatibility between the hydrogenated styrene elastomer and the thermoplastic polyester elastomer, leading to poor properties of the thermoplastic elastomer composite. In Comparative Example 2, the VA content of the ethylene-vinyl acetate copolymer used was too low, failing to allow for good dispersion of the thermoplastic polyester elastomer in the hydrogenated styrene elastomer, resulting in poor properties of the thermoplastic elastomer composite. In Comparative Example 3, the VA content of the ethylene-vinyl acetate copolymer used was too high, leading to excessive coating of the polar groups of the thermoplastic polyester elastomer, resulting in reduced polarity and decreased adhesive strength of the thermoplastic elastomer composite. In Comparative Example 4, the absence of maleic anhydride-grafted olefin copolymer elastomer resulted in poor dispersion of the thermoplastic polyester elastomer, leading to poor properties of the thermoplastic elastomer composite. In Comparative Example 5, the absence of thermoplastic polyester elastomer resulted in very poor low-temperature adhesive strength of the thermoplastic elastomer composite. In Comparative Example 6, the absence of ethylene-vinyl acetate copolymer resulted in low adhesive strength of the thermoplastic elastomer composite at both room and low temperatures. Comparative Example 7 contained thermoplastic polyurethane elastomer. The thermoplastic elastomer composite material exhibited good bonding strength at room temperature, but poor bonding strength at low temperatures. Comparative Example 8 contained ethylene-acrylic acid copolymer. The thermoplastic elastomer composite material showed poor bonding strength at both room temperature and low temperatures.

[0108] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A thermoplastic elastomer composite material, characterized in that, The components include the following parts by weight: 10-30 parts of hydrogenated styrene elastomer 20-60 parts softening oil 5-15 parts of polypropylene 4-16 parts of thermoplastic polyester elastomer, 3 to 11 parts of ethylene-vinyl acetate copolymer 5-15 parts of maleic anhydride-grafted polypropylene. 5-15 parts of maleic anhydride-grafted olefin copolymer elastomer; The VA content in the ethylene-vinyl acetate copolymer is 9-30 wt%. The softened oil has a kinematic viscosity ≥85 mmHg at 40°C. 2 / s.

2. The thermoplastic elastomer composite material according to claim 1, characterized in that, The hydrogenated styrene elastomer is at least one of hydrogenated styrene-butadiene block copolymer or hydrogenated styrene-isoprene block copolymer.

3. The thermoplastic elastomer composite material according to claim 1, characterized in that, The polypropylene is at least one of homopolymer polypropylene or copolymer polypropylene.

4. The thermoplastic elastomer composite material according to claim 1, characterized in that, The hard segment of the thermoplastic polyester elastomer is polyester, and the soft segment is aliphatic polyester and / or polyether.

5. The thermoplastic elastomer composite material according to claim 1, characterized in that, The Shore hardness D of the thermoplastic polyester elastomer is 35 to 72.

6. The thermoplastic elastomer composite material according to claim 1, characterized in that, The maleic anhydride grafting rate in the maleic anhydride-grafted polypropylene is 0.5–1.5 wt%.

7. The thermoplastic elastomer composite material according to claim 1, characterized in that, The maleic anhydride-grafted olefin copolymer elastomer is at least one of maleic anhydride-grafted ethylene-propylene copolymer elastomer or maleic anhydride-grafted ethylene-octene copolymer elastomer.

8. The thermoplastic elastomer composite material according to claim 1, characterized in that, The thermoplastic elastomer composite material also includes 0 to 2 parts of other additives.

9. A method for preparing the thermoplastic elastomer composite material according to any one of claims 1 to 8, characterized in that, The process includes the following steps: first, mixing hydrogenated styrene elastomer and softening oil, then mixing with the remaining components, melt extruding, and granulating to obtain the thermoplastic elastomer composite material.

10. The use of the thermoplastic elastomer composite material according to any one of claims 1 to 8 in the preparation of overcoating materials for nylon products.

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