Thermoplastic elastomer composite material as well as preparation method and application thereof

Abstract

The invention relates to a thermoplastic elastomer composite material as well as a preparation method and application thereof. 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 disclosed by the invention not only has good tensile strength, has good bonding strength to nylon at normal temperature, but also has good bonding strength to nylon at low temperature, and is very suitable for being used as a nylon encapsulation material in a cold application scene.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material modification, and more specifically, to a thermoplastic elastomer composite material, a preparation method thereof, and an application thereof. Background Art

[0002] A thermoplastic elastomer (TPE for short) is a material that has both the characteristics of high elasticity, high strength, and high resilience of rubber and the characteristics of being injection-moldable. TPE has many advantages such as environmental protection, non-toxicity, safety, a wide hardness range, excellent coloring property, soft touch, weather resistance, fatigue resistance, temperature resistance, superior processing performance, and no need for vulcanization. Therefore, as a new type of multifunctional environmental protection material, TPE has a very broad application market.

[0003] An important application of TPE materials is as overmolding materials, that is, TPE is overmolded on other materials. Nylon is a widely used engineering plastic with high mechanical strength, good heat resistance, and good friction resistance. In recent years, nylon has been widely used in toys, daily necessities, industrial products, etc. The products made of nylon materials often have a hard and smooth surface, with poor hand feeling during use and are prone to slipping. To solve this problem, a layer of TPE material can be coated on the surface of nylon to make it have a good hand feeling, increase the comfort of users, and can also greatly improve the aesthetics of the products. For example, a Chinese patent, a nylon overmolded TPE composite material, a preparation method thereof, and an application thereof, provides a TPE composite material for overmolding nylon.

[0004] Due to the wide application fields of nylon products, it is required that the TPE material used as the overmolding material for nylon can also adapt to the use environment of nylon products. In winter, the outdoor environmental temperature in northern China, especially in regions such as Northeast China, Inner Mongolia, and the Xinjiang Uygur Autonomous Region, can often reach about -30°C. When the natural environment is at -30°C, common TPE materials will become stiff, hard, have poor elasticity, and are prone to falling off from the adhered nylon, affecting the use effect of nylon products. Summary of the Invention

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

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

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

[0008] The above objects of the present invention are achieved by the following technical solutions:

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

[0010] 10 - 30 parts of a hydrogenated styrenic elastomer,

[0011] 20 - 60 parts of a softening oil,

[0012] 5 - 15 parts of polypropylene,

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

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

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

[0016] 5 - 15 parts of a 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 kinematic viscosity of the softening oil at 40°C ≥ 85 mm 2 / s.

[0019] In the present invention, the addition of polypropylene can provide certain mechanical strength to the material; the addition of maleic anhydride - grafted polypropylene can improve the compatibility between components, which is helpful for improving the mechanical strength and adhesion performance of the thermoplastic elastomer composite material.

[0020] The thermoplastic polyester elastomer has good low - temperature resistance, but the compatibility between the thermoplastic polyester elastomer and the hydrogenated styrenic elastomer is poor. Especially at low temperatures, the two are prone to separation, resulting in the thermoplastic polyester elastomer being unable to effectively endow the thermoplastic elastomer composite material mainly composed of the hydrogenated styrenic elastomer with low - temperature resistance.

[0021] The inventors of the present invention have found through research that by regulating the viscosity of the softening oil within a certain range, it can make the hydrogenated styrenic elastomer and the thermoplastic polyester elastomer well - compatible during the processing; on this basis, adding a maleic anhydride - grafted olefin copolymer elastomer, which has the characteristics of less crystallization and slow cooling, can not only increase the toughness of the material, but also improve the dispersibility of the thermoplastic polyester elastomer at low temperatures in the thermoplastic elastomer composite material as a compatibilizer. Further adding an ethylene - vinyl acetate copolymer with a specific VA content can improve the compatibility between the thermoplastic polyester elastomer and the hydrogenated styrenic elastomer. The combined action of the three enables the thermoplastic polyester elastomer to endow the thermoplastic elastomer composite material with good low - temperature resistance and good adhesion strength to nylon at low temperatures.

[0022] In addition, the combined action of a softening oil with a specific viscosity, a maleic anhydride-grafted olefin copolymer elastomer, and an ethylene-vinyl acetate copolymer with a specific VA content improves the compatibility of the materials, and further enhances the tensile strength of the thermoplastic elastomer composite material.

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

[0024] In the present 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 measured by titration.

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

[0026] In the present invention, the hydrogenated styrenic elastomer is used as the main resin, and its content accounts for at least 10wt% or more of the thermoplastic elastomer composite material.

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

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

[0029] In the present invention, the viscosity of the hydrogenated styrene-based elastomer can be measured in accordance with Q / SH1085 130-2006.

[0030] Preferably, the kinematic viscosity of the softening oil at 40 °C is ≥90 mm 2 / s.

[0031] More preferably, the kinematic viscosity of the softening oil at 40 °C is 90-150 mm 2 / s.

[0032] Even more preferably, the kinematic viscosity of the softening oil at 40 °C is 120-135 mm 2 / s.

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

[0034] Preferably, the polypropylene is at least one of homopolypropylene or copolymerized polypropylene.

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

[0036] Even more preferably, the copolymerized polypropylene is a copolymer of propylene and ethylene.

[0037] Even more preferably, the polypropylene is random copolymerized polypropylene. Selecting random copolymerized polypropylene, which has a lower crystallinity, can make the adhesion strength of the thermoplastic elastomer composite to nylon better at both room temperature and low temperature.

[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 the present invention, the melt flow rate of the polypropylene can be measured in accordance with 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 35-72.

[0043] In the present invention, the Shore hardness D of the thermoplastic polyester elastomer can be measured in accordance with the 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 obtained by testing with the chemical titration method (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 obtained by testing with the chemical titration method (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 select to add 0 - 50 parts of filler according to the actual requirements of the product. The filler is at least one of silica, wollastonite, calcium carbonate, glass microspheres, talc powder, kaolin, diatomite, barium sulfate or mica.

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

[0050] More preferably, the other additives are at least one of antioxidant, light stabilizer or lubricant.

[0051] Further 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] Further preferably, the light stabilizer is at least one of hindered amine light stabilizers or triazine light stabilizers.

[0053] Further 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; the triazine light stabilizer is at least one of UV - 234, UV - 236 or UV - 2373.

[0054] Further preferably, the lubricant is at least one of vinyl bisstearamide, hydroxy fatty acid lubricants, erucamide, zinc stearate, magnesium stearate or polyethylene wax.

[0055] The preparation method of the above-mentioned thermoplastic elastomer composite material comprises the following steps: first, a hydrogenated styrene-based elastomer and a softening oil are mixed, then mixed with the remaining components, melt-extruded, and granulated to obtain the thermoplastic elastomer composite material.

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

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

[0058] The application of the above-mentioned thermoplastic elastomer composite material in preparing the overmolding material for nylon products is also within the protection scope of the present invention.

[0059] Preferably, the nylon product is a product used at low temperature; 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 normal temperature, but also has good adhesion strength to nylon at low temperature, and is very suitable as the overmolding material for nylon in cold application scenarios. Specific Embodiments

[0062] In order 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 used to explain the present invention and are not used to limit the present invention, and various changes can be made within the scope defined by the claims of the present invention.

[0063] Some of the reagents selected in the embodiments and comparative examples of the present invention are described as follows:

[0064] Hydrogenated styrene-based elastomer 1#: Hydrogenated styrene-butadiene block copolymer, SEBS 7551, Li Changrong, Taiwan, China, viscosity 2000 cp;

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

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

[0067] Softening oil 2#: Naphthenic oil, 500SN, Beiran Industry, kinematic viscosity at 40 °C is 96 mm 2 / s;

[0068] Softening oil No. 3: Naphthenic oil, 350SN, Shanghai Daopu, with a kinematic viscosity of 65 - 72 mm 2 / s at 40°C;

[0069] Polypropylene No. 1: Random copolymer polypropylene, grade PP RJ766MO, manufacturer Borouge Chemical;

[0070] Polypropylene No. 2: Block copolymer polypropylene, grade PP K7100, manufacturer Yanshan Petrochemical;

[0071] Polypropylene No. 3: Homopolymer polypropylene, grade PP HP - 500N, manufacturer Basel;

[0072] Thermoplastic polyester elastomer No. 1: DH600, Shin Kwang of Taiwan, China, hardness 60D;

[0073] Thermoplastic polyester elastomer No. 2: DH400, Shin Kwang of Taiwan, China, hardness 40D;

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

[0075] Ethylene - vinyl acetate copolymer No. 1: VA content 22 wt%, UE631, Polymer Chemicals;

[0076] Ethylene - vinyl acetate copolymer No. 2: VA content 10 wt%, UE510, Polymer Chemicals;

[0077] Ethylene - vinyl acetate copolymer No. 3: VA content 8 wt%, UE508, Polymer Chemicals;

[0078] Ethylene - vinyl acetate copolymer No. 4: VA content 37 wt%, P3307, Mitsui of Japan;

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

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

[0081] Maleic anhydride grafted olefin copolymer elastomer No. 1: FB521A, maleic anhydride grafted ethylene - octene copolymer, Jia Yirong;

[0082] Maleic anhydride grafted olefin copolymer elastomer No. 2: CMG5805, maleic anhydride grafted ethylene - octene copolymer, Jia Yirong;

[0083] Other additive No. 1: Obtained by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1, both antioxidant 1010 and antioxidant 168 are commercially available;

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

[0085] Unless otherwise specified, each component selected in the parallel examples and comparative examples (such as Other additive 1# and Other additive 2#) is the same commercially available product.

[0086] The performance of the thermoplastic elastomer composites provided in the examples and comparative examples of the present invention was determined by the following test methods:

[0087] (1) Tensile strength test method: Tested in accordance with the ISO527-2012 standard. After injection molding into a 2*100*100mm standard square plate, it was cut into Type 2 specimens using a cutter, and after standing at room temperature for 24h, it was tested on a tensile machine. The molding cycle was based on the cycle of injection molding tensile specimens.

[0088] (2) Adhesive strength test method: Includes adhesive strength at room temperature and adhesive strength at low temperature. Adhesive strength at room temperature: In accordance with the requirements of the GB / T 7760-2003 standard, the thermoplastic elastomer composite to be tested was injection molded onto a PA substrate specimen using an injection molding machine in a specific mold. The injection temperature was 255°C. After standing at room temperature (25°C) for 24h, 90° peeling was carried out to test the bonding strength between the thermoplastic elastomer composite and the PA substrate specimen; Adhesive strength at low temperature: After the sample was injection molded into a 2*100*100mm standard square plate and coated with a PA substrate, it was placed at -35°C for 8h and then its adhesive strength was tested. Generally, it is considered that the peel force ≥ 2.0N / mm is of practical value.

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

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

[0091] 2) Mix the premix with other components, and then add it to the twin-screw extruder from the main feeder. After melting and extrusion, granulation is carried out to obtain the thermoplastic elastomer composite; among them, the length-diameter ratio of the screw of the twin-screw extruder is 26:1; the screw speed is 450r / min, and the temperatures of each zone of the melting temperature are 80°C, 120°C, 190°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C and 210°C.

[0092] Examples 1 to 10

[0093] Examples 1 to 10 provide a series of thermoplastic elastomer composites, and their formulations are shown in Table 1.

[0094] Table 1 Formulations of Examples 1 to 10 (parts by weight)

[0095]

[0096]

[0097] Comparative Examples 1-8

[0098] Comparative Examples 1-8 provide a series of thermoplastic elastomer composites, and their formulations are shown in Table 2.

[0099] Table 2 Formulations of Comparative Examples 1-8 (parts by weight)

[0100]

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

[0102] Table 3 Property results of the thermoplastic elastomer composites of each example and comparative example

[0103]

[0104]

[0105] It can be seen from Table 3 that:

[0106] The tensile strength of the thermoplastic elastomer composites of Examples 1-10 is all above 5.0 MPa, the normal temperature bonding strength is all above 3.3 N / mm, and the low temperature bonding strength is all above 2.6 N / mm, indicating that the present invention not only has good tensile strength and good bonding strength to nylon at normal temperature, but also has good bonding strength to nylon at low temperature, and is very suitable as a coating material for nylon in cold application scenarios.

[0107] The viscosity of the softening oil selected in Comparative Example 1 was too low, resulting in poor compatibility between the hydrogenated styrene-based elastomer and the thermoplastic polyester elastomer, and poor properties of the thermoplastic elastomer composite. The VA content of the ethylene-vinyl acetate copolymer selected in Comparative Example 2 was too low to enable the thermoplastic polyester elastomer to be well dispersed in the hydrogenated styrene-based elastomer, and the properties of the thermoplastic elastomer composite were poor. The VA content of the ethylene-vinyl acetate copolymer selected in Comparative Example 3 was too high, resulting in the polar groups of the thermoplastic polyester elastomer being overly coated, leading to a decrease in the polarity of the thermoplastic elastomer composite and a decrease in the adhesion strength. In Comparative Example 4, the maleic anhydride-grafted olefin copolymer elastomer was not added, resulting in the thermoplastic polyester elastomer being unable to be well dispersed, and the properties of the thermoplastic elastomer composite were poor. In Comparative Example 5, the thermoplastic polyester elastomer was not added, and the low-temperature adhesion strength of the thermoplastic elastomer composite was very poor. In Comparative Example 6, the ethylene-vinyl acetate copolymer was not added, and the adhesion strength of the thermoplastic elastomer composite at room temperature and low temperature was low. In Comparative Example 7, the thermoplastic polyurethane elastomer was added, and the room-temperature adhesion strength of the thermoplastic elastomer composite was good, but the low-temperature adhesion strength was poor. In Comparative Example 8, the ethylene-acrylic acid copolymer was added, and the room-temperature adhesion strength and low-temperature adhesion strength of the thermoplastic elastomer composite were poor.

[0108] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

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

2. The thermoplastic elastomer composite material according to claim 1, characterized in that: The hydrogenated styrene elastomer is at least one of a hydrogenated styrene-butadiene block copolymer and a 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 homopolypropylene 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 35-72.

6. The thermoplastic elastomer composite material according to claim 1, characterized in that: The maleic anhydride grafting rate of 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 a maleic anhydride grafted ethylene-propylene copolymer elastomer and a 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. The method for preparing the thermoplastic elastomer composite material according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: firstly mixing hydrogenated styrene elastomer and softening oil, then mixing with remaining components, melt-extruding, and granulating to obtain the thermoplastic elastomer composite material.

10. Use of the thermoplastic elastomer composite material according to any one of claims 1 to 8 in preparing a coating material for nylon products.

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