A thermoplastic elastomer composition, its preparation method and applications

Abstract

The present invention relates to a thermoplastic elastomer composition, a preparation method and an application thereof. The thermoplastic elastomer composition comprises the following components: a first SEBS thermoplastic elastomer, a second SEBS thermoplastic elastomer, a third SEBS thermoplastic elastomer and a compatibilizer; the number-average molecular weights of the first SEBS thermoplastic elastomer, the second SEBS thermoplastic elastomer and the third SEBS thermoplastic elastomer are not equal; the compatibilizer comprises a graft copolymer formed by polypropylene, SEBS thermoplastic elastomer and maleic anhydride. The coating material formed by the thermoplastic elastomer composition of the present invention has both high fluidity and high bonding strength.

Description

Technical Field

[0001] The present invention relates to the technical field of track materials, and in particular to a thermoplastic elastomer composition, a preparation method thereof and an application thereof. Background Art

[0002] Styrene-based TPE elastomers have the characteristics of rubber. The physical properties and hardness can be adjusted. The hardness can be adjusted from 0 to 100 degrees Shore hardness, which is convenient and flexible. The excellent soft touch and anti-slip properties improve the comfort of the product and provide a variety of possible options for users with different material needs. It is widely used in sports equipment, electronic appliances, daily necessities, medical products, auto parts, hardware tools, etc. The tacit cooperation between TPE and hard plastics is common.

[0003] TPE components are generally 0.5 to 3mm thick. If they are too thick, the TPE material will not flow well, resulting in defects such as glue shortage and poor adhesion. Therefore, when producing TPE materials for high-flow encapsulation, SEBS is generally filled with as much oil as possible to improve the material's flow properties. However, this can easily cause gate breakage during injection molding, oil leakage in the finished product, and poor wear resistance. Insufficient interpenetration at the encapsulation contact interface can form a poor weld layer at the joint surface, preventing the TPE from firmly bonding to the hard plastic and effectively preventing effective adhesion, resulting in a weak TPE encapsulation.

[0004] CN103571125A discloses a method for preparing an elastomeric nylon coating material. The disclosed coating material is mainly composed of hydrogenated styrene butadiene block copolymer (i.e., SEBS), a compatibilizer, filler oil, filler, and hydrogenated petroleum resin. The disclosed coating material has a good coating effect on nylon 6, a low injection molding temperature (around 170°C), and a good hand feel. The disclosed coating material is mainly used for coating power tool handles.

[0005] CN101921417A discloses a special coating material for glass fiber reinforced polypropylene. The material is made from the following raw materials in the following weight ratios: 25-50% SEBS; 0-50% softener; 0-2% lubricant; 0-1% coupling agent; 0-25% filler; 0-15% polypropylene; 0.2-1% antioxidant AT-10; and 0.2-1% antioxidant AT-168. The disclosed beneficial effects are primarily reflected in: using existing elastomers, achieving a rubber-like effect without the need for dynamic vulcanization; and the material is reusable and provides excellent coating effects.

[0006] At present, in order to improve the bonding ability, generally the amount of the overmolding material is increased, that is, the amount of polypropylene is increased in the overmolding material when overmolding polypropylene, or the amount of the graft compatibilizer is increased. This easily leads to too high hardness of the overmolded product, loss of hand feeling, or a substantial increase in cost. Moreover, improving fluidity and bonding strength are contradictory to each other. When one of them is improved, the performance of the other will decline.

[0007] In summary, it is crucial to develop a coating material with both high fluidity and bonding strength. Summary of the Invention

[0008] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a thermoplastic elastomer composition, its preparation method and application. The thermoplastic elastomer composition has both high fluidity and bonding strength and is suitable as a coating material.

[0009] To achieve this purpose, the present invention adopts the following technical solutions:

[0010] In the first aspect, the present invention provides a thermoplastic elastomer composition, which comprises the following components:

[0011] The first SEBS thermoplastic elastomer, the second SEBS thermoplastic elastomer, the third SEBS thermoplastic elastomer and a compatibilizer;

[0012] The number-average molecular weights of the first SEBS thermoplastic elastomer, the second SEBS thermoplastic elastomer and the third SEBS thermoplastic elastomer are not equal;

[0013] The compatibilizer comprises a graft copolymer formed by polypropylene, SEBS thermoplastic elastomer and maleic anhydride.

[0014] In the present invention, three SEBS (styrene-ethylene-butene-styrene block copolymer) thermoplastic elastomers with molecular weight gradients are adopted to make the thermoplastic elastomer composition have both high strength and high fluidity. Then, in combination with a specific compatibilizer, the compatibility of each component is increased, and the fluidity and bonding strength of the thermoplastic elastomer composition are further improved, which is suitable for coating materials.

[0015] Preferably, the number-average molecular weight of the first SEBS thermoplastic elastomer is 200,000-360,000 g / mol, such as 220,000 g / mol, 240,000 g / mol, 260,000 g / mol, 280,000 g / mol, 300,000 g / mol, 320,000 g / mol, 340,000 g / mol, etc.

[0016] Preferably, the number-average molecular weight of the second SEBS thermoplastic elastomer is 80,000 - 200,000 g / mol and not equal to 200,000 g / mol, such as 100,000 g / mol, 120,000 g / mol, 140,000 g / mol, 160,000 g / mol, 180,000 g / mol, etc.

[0017] Preferably, the number-average molecular weight of the third SEBS thermoplastic elastomer is 40,000 - 70,000 g / mol, such as 45,000 g / mol, 50,000 g / mol, 55,000 g / mol, 60,000 g / mol, 65,000 g / mol, etc.

[0018] Preferably, the thermoplastic elastomer composition comprises the following components by weight parts:

[0019]

[0020] In the present invention, SEBS thermoplastic elastomers with different molecular weights and the compatibilizer are used in combination at specific addition amounts, which can form a thermoplastic elastomer composition with high fluidity and high adhesion strength to the greatest extent. The weight parts of the first SEBS thermoplastic elastomer are 5 - 20 parts. If the addition amount is too high, it will lead to insufficient fluidity, resulting in lack of glue and water flow marks during injection molding; if the addition amount is too low, it will lead to insufficient physical and mechanical properties such as impact resistance and tensile strength. The weight parts of the second SEBS thermoplastic elastomer are 15 - 30 parts. If the addition amount is too high, it will lead to insufficient fluidity, resulting in lack of glue and water flow marks during injection molding; if the addition amount is too low, it will lead to insufficient physical and mechanical properties such as impact resistance and tensile strength. The weight parts of the third SEBS thermoplastic elastomer are 5 - 15 parts. If the addition amount is too high, it will lead to insufficient physical and mechanical properties such as impact and tensile strength; if the addition amount is too low, it will lead to insufficient fluidity and cannot improve the processability of the product. The weight parts of the compatibilizer are 5 - 10 parts. If the addition amount is too high, it will lead to excessive polarity, too high peel strength, and easy breakage of the rubber strip; if the addition amount is too low, it will lead to insufficient bonding performance between the composition and the physical properties of the coated material, and easy peeling.

[0021] In the present invention, the weight parts of the first SEBS thermoplastic elastomer are 5 - 20 parts, such as 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, etc.

[0022] The weight parts of the second SEBS thermoplastic elastomer are 15 - 30 parts, such as 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, etc.

[0023] The weight parts of the third SEBS thermoplastic elastomer are 5 - 15 parts, such as 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, etc.

[0024] The weight parts of the compatibilizer are 5-10 parts, such as 6 parts, 7 parts, 8 parts, 9 parts, etc.

[0025] Preferably, in the compatibilizer, the weight parts of the polypropylene are 70-80 parts, such as 72 parts, 74 parts, 76 parts, 78 parts, etc.;

[0026] The weight parts of the SEBS thermoplastic elastomer are 20-30 parts, such as 22 parts, 24 parts, 26 parts, 28 parts, etc.;

[0027] The weight parts of the maleic anhydride are 2-3 parts, such as 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts, etc.

[0028] Preferably, the number-average molecular weight of the SEBS thermoplastic elastomer is 40000-70000 g / mol, such as 45000 g / mol, 50000 g / mol, 55000 g / mol, 60000 g / mol, 65000 g / mol, etc.

[0029] In the present invention, the product of the graft reaction of the SEBS thermoplastic elastomer, maleic anhydride and polypropylene in a specific ratio is used as the compatibilizer, which is more conducive to improving the compatibility of different components.

[0030] Preferably, the thermoplastic elastomer composition further comprises other resins and / or additives.

[0031] Preferably, the other resin comprises polypropylene.

[0032] Preferably, the polypropylene comprises first polypropylene and / or second polypropylene;

[0033] The melt index of the first polypropylene is 10-30 g / 10 min, such as 12 g / 10 min, 14 g / 10 min, 16 g / 10 min, 18 g / 10 min, 20 g / 10 min, 22 g / 10 min, 24 g / 10 min, 26 g / 10 min, 28 g / 10 min, etc.

[0034] The melt index of the second polypropylene is 31-80 g / 10 min, such as 40 g / 10 min, 50 g / 10 min, 60 g / 10 min, 70 g / 10 min, etc.

[0035] In the present invention, the test conditions of the melt index are: at 230 °C and 2.16 kg.

[0036] In the present invention, the reason for using polypropylene with two melt indices is to simultaneously possess excellent physical and mechanical strength and excellent processing performance - the high molecular weight part is used to ensure its physical and mechanical strength, and the low molecular weight part plays a lubricating role in the resin to improve the processability of the product.

[0037] Preferably, the additives include lubricants and / or antioxidants.

[0038] Preferably, the lubricant includes any one or a combination of at least two of zinc stearate, white oil or naphthenic oil. Typical but non-limiting combinations include: the combination of zinc stearate and white oil, the combination of white oil and naphthenic oil, the combination of zinc stearate, white oil and naphthenic oil, etc.

[0039] Preferably, the antioxidant includes antioxidant 1010 and / or antioxidant 168.

[0040] Preferably, the weight parts of the other resin are 5 - 60 parts, such as 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, etc.

[0041] Preferably, the weight parts of the polypropylene are 5 - 50 parts, such as 10 parts, 15 parts, 20 parts, 30 parts, 35 parts, 40 parts, 45 parts, etc.

[0042] Preferably, the weight parts of the first polypropylene are 5 - 20 parts, such as 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, etc.

[0043] Preferably, the weight parts of the second polypropylene are 5 - 30 parts, such as 10 parts, 15 parts, 20 parts, 25 parts, etc.

[0044] Preferably, the weight parts of the additives are 0 - 100 parts, such as 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, etc.

[0045] Preferably, the weight parts of the lubricant are 0 - 82 parts, such as 5 parts, 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, etc.

[0046] Preferably, the weight parts of the zinc stearate are 0 - 2 parts, such as 0.1 part, 0.2 part, 0.4 part, 0.6 part, 0.8 part, 1 part, 1.2 part, 1.4 part, 1.6 part, 1.8 part, etc.

[0047] Preferably, the weight parts of the white oil are 30 - 50 parts, such as 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 parts, etc.

[0048] Preferably, the weight parts of the naphthenic oil are 20 - 30 parts, such as 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, etc.

[0049] Preferably, the weight parts of the antioxidant are 0.1 - 0.4 parts, such as 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, etc.

[0050] Preferably, the weight parts of the antioxidant 1010 are 0.1 - 0.2 parts, such as 0.12 parts, 0.14 parts, 0.16 parts, 0.18 parts, etc.

[0051] Preferably, the weight parts of the antioxidant 168 are 0.1 - 0.2 parts, such as 0.12 parts, 0.14 parts, 0.16 parts, 0.18 parts, etc.

[0052] In a second aspect, the present invention provides a method for preparing the thermoplastic elastomer composition described in the first aspect, and the preparation method includes the following steps:

[0053] Mix the first SEBS thermoplastic elastomer, the second SEBS thermoplastic elastomer, the third SEBS thermoplastic elastomer and the compatibilizer, and process to obtain the thermoplastic elastomer composition;

[0054] Among the first SEBS thermoplastic elastomer, the second SEBS thermoplastic elastomer, and the third SEBS thermoplastic elastomer, the first SEBS thermoplastic elastomer has the highest number-average molecular weight, the second SEBS thermoplastic elastomer has a medium number-average molecular weight, and the third SEBS thermoplastic elastomer has the lowest number-average molecular weight;

[0055] The compatibilizer includes a graft copolymer formed by polypropylene, SEBS thermoplastic elastomer and maleic anhydride.

[0056] Preferably, the mixing method includes stirring.

[0057] Preferably, the rotation speed of the stirring is 10 - 500 r / min, such as 50 r / min, 100 r / min, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, etc.

[0058] Preferably, other resins and / or additives are added after the mixing.

[0059] Preferably, stirring is carried out during the addition of other resins and / or additives.

[0060] Preferably, the mixed materials are heated before adding other resins and / or additives.

[0061] Preferably, the other resin includes polypropylene.

[0062] Preferably, the additives include lubricants and / or antioxidants.

[0063] Preferably, the lubricant includes any one or a combination of at least two of zinc stearate, white oil or naphthenic oil. Typical but non-limiting combinations include: the combination of zinc stearate and white oil, the combination of white oil and naphthenic oil, the combination of zinc stearate, white oil and naphthenic oil, etc.

[0064] Preferably, when adding the other resin and / or additives, after adding white oil and / or naphthenic oil, other components are added.

[0065] Preferably, the processing method sequentially includes melt extrusion, strand drawing, air cooling, pelletizing and drying.

[0066] Preferably, the temperature of the melt extrusion is 180 - 240 °C, such as 190 °C, 200 °C, 210 °C, 220 °C, 230 °C, etc.

[0067] Preferably, the preparation method of the compatibilizer includes: mixing polypropylene, SEBS thermoplastic elastomer, maleic anhydride and processing aids, and performing melt processing to obtain the compatibilizer.

[0068] Preferably, the processing aids include initiators and / or anti-crosslinking agents.

[0069] In a third aspect, the present invention provides a coating material, and the coating material includes the thermoplastic elastomer composition described in the first aspect.

[0070] Compared with the prior art, the present invention has the following beneficial effects:

[0071] (1) The coating material formed by the thermoplastic elastomer composition of the present invention has both high fluidity and high bonding strength.

[0072] (2) The melt flow rate of the coating material formed by the thermoplastic elastomer composition of the present invention is above 82 g / 10 min, and the peel strength is above 3.41 MPa. Detailed Embodiments

[0073] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0074] In the present invention, the raw material information of each raw material is as follows:

[0075] 1. Raw materials of the compatibilizer:

[0076] SEBS: produced by Zhonghe;

[0077] Initiator: Named 2,5-dimethyl-2,5-di-tert-butyl peroxyethane, purchased from the market, grade 101;

[0078] Graft monomer: Named maleic anhydride;

[0079] 2. Raw materials of the thermoplastic elastomer composition

[0080] First SEBS thermoplastic elastomer: The average number-average molecular weight is 320,000, produced by Zhonghe, grade S3001;

[0081] Second SEBS thermoplastic elastomer: The average number-average molecular weight is 180,000, produced by Zhonghe, grade 3004;

[0082] Third SEBS thermoplastic elastomer: The average number-average molecular weight is 60,000, produced by Zhonghe, grade 3002;

[0083] Medium melt index polypropylene: The melt index is 26 g / 10 min, the test standard is 230 °C - 2.16 kg, grade K7726;

[0084] High melt index polypropylene: The melt index is 60 g / 10 min, the test standard is 230 °C - 2.16 kg, grade MN60;

[0085] Naphthenic oil: KN4006;

[0086] White oil: 32#;

[0087] White oil: 68#;

[0088] K-resin: Produced by Zhonghe, grade SL803G;

[0089] SBS: Produced by Zhonghe, grade S3008;

[0090] SEBS-g-MAH: Produced by Zhonghe.

[0091] Example 1

[0092] This example provides a coating material, which is prepared by the following method. The preparation method includes the following steps:

[0093] (1) In a high-speed mixer at 500 liters, add 75 kg of polypropylene, 25 kg of SEBS, 2.5 kg of maleic anhydride, 0.25 kg of initiator and 0.25 kg of anti-crosslinking agent, start stirring and mixing for 3 minutes; then, discharge the mixture and transfer it to the feeder of a twin-screw extruder, start the twin-screw extruder and the feeder, carry out grafting reaction at 190 °C, pelletize to obtain a compatibilizer;

[0094] (2) In a 500-liter high-speed mixer, add 10 kg of the first SEBS thermoplastic elastomer, 20 kg of the second SEBS thermoplastic elastomer, and 6 kg of the third SEBS thermoplastic elastomer. Then start the high-speed mixer and stir at a low speed of 144 r / min (5 Hz). While stirring, evenly sprinkle 35 kg of naphthenic oil. After adding the oil, let it stand for 12 hours until the oil is absorbed. During this process, it is necessary to start the mixer from time to time to turn over the material to avoid caking, and obtain the oil-extended SEBS;

[0095] (3) After the oil is completely absorbed, add 7 kg of compatibilizer, 10 kg of medium melt index polypropylene, 7 kg of high melt index polypropylene, 1 kg of zinc stearate, 0.15 kg of antioxidant 1010, and 0.15 kg of antioxidant 168, and mix evenly;

[0096] (4) After the mixed material is kneaded, extruded, drawn into strips, air-cooled, pelletized, and dried by a twin-screw extruder at 210 °C, the coated material is obtained.

[0097] Example 2

[0098] This example provides a coated material, which is prepared by the following method. The preparation method includes the following steps:

[0099] (1) In a 500-liter high-speed mixer, add 80 kg of polypropylene, 20 kg of SEBS, 2.5 kg of maleic anhydride, 0.25 kg of initiator, and 0.25 kg of anti-crosslinking agent. Start stirring and mixing for 3 minutes. Then, discharge the mixed material and transfer it to the feeder of the twin-screw extruder. Start the twin-screw extruder and the feeder, and carry out graft reaction at 200 °C, and pelletize to obtain the compatibilizer;

[0100] (2) In a 500-liter high-speed mixer, add 8 kg of the first SEBS thermoplastic elastomer, 18 kg of the second SEBS thermoplastic elastomer, and 10 kg of the third SEBS thermoplastic elastomer. Then start the high-speed mixer and stir at a low speed of 144 r / min (5 Hz) and heat up to 80 °C. While stirring, evenly sprinkle 45 kg of naphthenic oil. After adding the oil, let it stand for 20 min to 24 hours;

[0101] (3) After the oil is completely absorbed, add 7 kg of compatibilizer, 18 kg of medium melt index polypropylene, 5 kg of high melt index polypropylene, 8 kg of K-resin or SBS, 1 kg of zinc stearate, 0.15 kg of antioxidant 1010, and 0.15 kg of antioxidant 168, and mix evenly;

[0102] (4) After the mixed material is kneaded, extruded, drawn into strips, air-cooled, pelletized, and dried by a twin-screw extruder at 210 °C, the coated material is obtained.

[0103] Example 3

[0104] The difference between this example and Example 2 is that the medium melt index polypropylene is replaced with an equal mass of high melt index polypropylene, and the rest are the same as in Example 2.

[0105] Example 4

[0106] The difference between this example and Example 2 is that the high melt index polypropylene is replaced with an equal mass of medium melt index polypropylene, and the rest are the same as in Example 2.

[0107] Comparative Example 1

[0108] This comparative example provides a coating material, and the coating material is prepared by the following method. The preparation method includes the following steps:

[0109] (1) In a high-speed mixer at 500 liters, add 36 kg of medium molecular weight SEBS, then start the high-speed mixer and stir at a low speed of 144 r / min (5 Hz). While stirring, evenly sprinkle 45 kg of naphthenic oil. After adding the oil, let it stand for 12 hours until the oil is absorbed. During this process, it is necessary to start the mixer from time to time to turn over the material to avoid agglomeration of the material, and obtain oil-extended SEBS;

[0110] (2) After the oil is completely absorbed, add 5 kg of compatibilizer SEBS-g-MAH, 18 kg of medium melt index polypropylene, 5 kg of high melt index polypropylene, 1 kg of zinc stearate, 0.15 kg of antioxidant 1010 and 0.15 kg of antioxidant 168 and mix evenly;

[0111] (3) After the mixed material is treated by processes such as kneading and extruding, strip drawing, air cooling, pelletizing and drying through a twin-screw extruder at 210 °C, the coating material is obtained.

[0112] Comparative Example 2

[0113] This comparative example provides a coating material, and the coating material is prepared by the following method. The preparation method includes the following steps:

[0114] (1) In a high-speed mixer at 500 liters, add 32 kg of the second SEBS thermoplastic elastomer, then start the high-speed mixer and stir at a low speed of 144 r / min (5 Hz). While stirring, evenly sprinkle 29 kg of naphthenic oil. After adding the oil, let it stand for 20 min to 24 hours until the oil is absorbed. During this process, it is necessary to start the mixer from time to time to turn over the material to avoid agglomeration of the material, and obtain oil-extended SEBS;

[0115] (2) After the oil is completely absorbed, add 5 kg of compatibilizer SEBS-g-MAH, 30 kg of high melt index polypropylene, 5 kg of high melt index polypropylene, 8 kg of K-resin, 1 kg of zinc stearate, 0.15 kg of antioxidant 1010, and 0.15 kg of antioxidant 168, and mix evenly;

[0116] (3) After the above-mentioned mixed materials are processed through processes such as kneading and extruding at 210 °C by a twin-screw extruder, strand drawing, air cooling, pelletizing, and drying, the coated material is obtained.

[0117] Comparative Example 3

[0118] The difference between this comparative example and Example 2 is that 8 kg of the first SEBS thermoplastic elastomer, 18 kg of the second SEBS thermoplastic elastomer, and 10 kg of the third SEBS thermoplastic elastomer are replaced with 18 kg of the first SEBS thermoplastic elastomer and 18 kg of the second SEBS thermoplastic elastomer, and the rest are the same as in Example 2.

[0119] Comparative Example 4

[0120] The difference between this comparative example and Example 1 is that 10 kg of the first SEBS thermoplastic elastomer, 20 kg of the second SEBS thermoplastic elastomer, and 6 kg of the third SEBS thermoplastic elastomer are replaced with 12 kg of the first SEBS thermoplastic elastomer and 20 kg of the third SEBS thermoplastic elastomer, and the rest are the same as in Example 1.

[0121] Comparative Example 5

[0122] The difference between this comparative example and Example 1 is that 8 kg of the first SEBS thermoplastic elastomer, 18 kg of the second SEBS thermoplastic elastomer, and 10 kg of the third SEBS thermoplastic elastomer are replaced with 26 kg of the first SEBS thermoplastic elastomer, and the rest are the same as in Example 2.

[0123] Performance Test

[0124] The coated materials described in Examples 1-4 and Comparative Examples 1-5 were tested as follows:

[0125] (1) Melt flow rate: Conducted on 5 kg of raw materials at 190 °C in accordance with GB / T 3682;

[0126] (2) Peel strength: Conducted in accordance with GB / T 2790.

[0127] The test results are summarized in Table 1.

[0128] Table 1

[0129]

[0130]

[0131] Analysis of the data in Table 1 shows that the melt flow rate of the coating material formed by the thermoplastic elastomer composition of the present invention is above 82 g / 10 min, and the peel strength is above 3.41 MPa. The coating material formed by the thermoplastic elastomer composition has both high fluidity and high adhesive strength.

[0132] Analysis of Comparative Examples 1-2 and Examples 1-2 shows that the performance of Comparative Examples 1-2 is inferior to that of Examples 1-2, proving that the thermoplastic elastomer composition formed by using the compatibilizer of the present invention has better performance.

[0133] Analysis of Comparative Example 3 and Example 2 shows that the performance of Comparative Example 3 is inferior to that of Example 2, proving that the thermoplastic elastomer composition formed by SEBS with three molecular weight gradients has better performance than that formed by SEBS with two molecular weight gradients.

[0134] The results of analyzing Comparative Example 4 and Example 1 are the same as above.

[0135] Analysis of Comparative Example 5 and Example 2 shows that the performance of Comparative Example 5 is inferior to that of Example 2, proving that the thermoplastic elastomer composition formed by SEBS with three molecular weight gradients has better performance than that formed by SEBS with a single molecular weight.

[0136] Analysis of Examples 3-4 and Example 2 shows that the performance of Examples 3-4 is inferior to that of Example 2, proving that the thermoplastic elastomer composition formed by adding polypropylene with two melt indices has better performance.

[0137] The present invention uses the above examples to illustrate the detailed method of the present invention, but the present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and public scope of the present invention.

Claims

1. A thermoplastic elastomer composition, characterized in that, The thermoplastic elastomer composition comprises the following components by weight parts: The compatibilizer comprises a graft copolymer formed from polypropylene, SEBS thermoplastic elastomer, and maleic anhydride; The number-average molecular weight of the first SEBS thermoplastic elastomer is 200,000 - 360,000 g / mol; The number-average molecular weight of the second SEBS thermoplastic elastomer is 80,000 - 200,000 g / mol and is not equal to 200,000 g / mol; The number-average molecular weight of the third SEBS thermoplastic elastomer is 40,000 - 70,000 g / mol; The melt index of the first polypropylene is 10 - 30 g / 10 min; The melt index of the second polypropylene is 31 - 70 g / 10 min.

2. The thermoplastic elastomer composition according to claim 1, wherein In the compatibilizer, the weight parts of the polypropylene are 70 - 80 parts; The weight parts of the SEBS thermoplastic elastomer are 20 - 30 parts; The weight parts of the maleic anhydride are 2 - 3 parts.

3. The thermoplastic elastomer composition according to claim 1, wherein In the compatibilizer, the number-average molecular weight of the SEBS thermoplastic elastomer is 40,000 - 70,000 g / mol.

4. The thermoplastic elastomer composition according to claim 1, wherein The thermoplastic elastomer composition further comprises additives.

5. The thermoplastic elastomer composition according to claim 4, characterized in that, The additives comprise a lubricant and / or an antioxidant.

6. The thermoplastic elastomer composition according to claim 5, wherein The lubricant comprises any one or a combination of at least two of zinc stearate, white oil, or naphthenic oil.

7. The thermoplastic elastomer composition according to claim 5, characterized in that, The antioxidant comprises antioxidant 1010 and / or antioxidant 168.

8. The thermoplastic elastomer composition according to claim 4, wherein The weight parts of the additives are 0 - 100 parts.

9. The thermoplastic elastomer composition according to claim 5, wherein The weight parts of the lubricant are 0 - 82 parts.

10. The thermoplastic elastomer composition according to claim 6, characterized in that, The weight parts of the zinc stearate are 0 - 2 parts.

11. The thermoplastic elastomer composition according to claim 6, wherein The weight parts of the white oil are 30 - 50 parts.

12. The thermoplastic elastomer composition according to claim 6, wherein The weight parts of the naphthenic oil are 20 - 30 parts.

13. The thermoplastic elastomer composition according to claim 5, wherein The weight parts of the antioxidant are 0.1 - 0.4 parts.

14. The thermoplastic elastomer composition according to claim 7, characterized in that, The weight parts of the antioxidant 1010 are 0.1 - 0.2 parts.

15. The thermoplastic elastomer composition according to claim 7, characterized in that, The weight parts of the antioxidant 168 are 0.1 - 0.2 parts.

16. A method for preparing the thermoplastic elastomer composition according to any one of claims 1-15, characterized in that, The preparation method comprises the following steps: Mix the first SEBS thermoplastic elastomer, the second SEBS thermoplastic elastomer, the third SEBS thermoplastic elastomer, the first polypropylene, the second polypropylene, and the compatibilizer, and process to obtain the thermoplastic elastomer composition; Among the first SEBS thermoplastic elastomer, the second SEBS thermoplastic elastomer, and the third SEBS thermoplastic elastomer, the first SEBS thermoplastic elastomer has the highest number-average molecular weight, the second SEBS thermoplastic elastomer has a medium number-average molecular weight, and the third SEBS thermoplastic elastomer has the lowest number-average molecular weight; The compatibilizer comprises a graft copolymer formed from polypropylene, SEBS thermoplastic elastomer, and maleic anhydride.

17. The preparation method according to claim 16, characterized in that, The mixing method comprises stirring.

18. The preparation method according to claim 17, characterized in that, The rotation speed of the stirring is 10 - 500 r / min.

19. The preparation method according to claim 16, characterized in that, After mixing, adding additives is further included.

20. The preparation method according to claim 19, wherein Stirring is carried out during the process of adding additives.

21. The preparation method according to claim 19, wherein, Before adding the additives, heat the mixed materials.

22. The preparation method according to claim 19, wherein The additives comprise a lubricant and / or an antioxidant.

23. The preparation method according to claim 22, wherein The lubricant comprises any one or a combination of at least two of zinc stearate, white oil, or naphthenic oil.

24. The preparation method according to claim 23, characterized in that, When adding the additives, after adding white oil and / or naphthenic oil, then add other components.

25. The preparation method according to claim 16, wherein, The processing method sequentially includes melt extrusion, strand drawing, air cooling, pelletizing, and drying.

26. The preparation method according to claim 25, characterized in that, The temperature of the melt extrusion is 180 - 240 °C.

27. The preparation method according to claim 16, wherein, The preparation method of the compatibilizer includes: mixing polypropylene, SEBS thermoplastic elastomer, maleic anhydride, and a processing aid, and performing melt processing to obtain the compatibilizer.

28. The preparation method according to claim 27, wherein The processing aid includes an initiator and / or an anti-crosslinking agent.

29. A coating material, characterized in that, The coating material includes the thermoplastic elastomer composition according to any one of claims 1 - 15.

Images