Thermoplastic elastomer composition, process for the preparation thereof and use thereof

Abstract

This invention discloses a thermoplastic elastomer composition, its preparation method, and its applications. The thermoplastic elastomer composition of this invention comprises the following components: PP resin I, SEBS, TPV, glass fiber powder, paraffin oil, antioxidant, and light stabilizer; wherein, the PP resin I conforms to ISO 1133-1-2011 standard, with a melt index of 80–130 g / 10 min at 230°C and 2.16 kg; the SEBS has a weight-average molecular weight of 80,000–160,000; and the TPV comprises PP resin II and EPDM. The thermoplastic elastomer composition of this invention combines PP resin with a specific melt index, SEBS with a specific weight-average molecular weight, and TPV, resulting in a thermoplastic elastomer composition that possesses both high fluidity and low gloss, as well as excellent high-temperature resistance.

Description

Technical Field

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

[0002] Thermoplastic elastomers not only possess the excellent elasticity of thermosetting rubbers but also the thermoplastic processability of plastics, making them widely used in the automotive, electronics, industrial components, and daily necessities industries. Especially in the automotive sector, thermoplastic elastomers are frequently used to manufacture large, thin-walled automotive interior components. This requires thermoplastic elastomer materials to have low odor, high flowability, low gloss, and good resistance to high and low temperatures.

[0003] Currently, commonly used thermoplastic elastomers mainly include polyvinyl chloride (PVC) elastomers, block styrene elastomers (TPS), dynamically vulcanized thermoplastic elastomers (TPV), and polyurethane elastomers (TPU). Among them, PVC elastomers are gradually being replaced by other elastomers due to their poor high and low temperature resistance, high specific gravity, and halogen content, which is not environmentally friendly. TPV (EPDM / PP) products have excellent high and low temperature resistance, low compression set, and low gloss, but due to the dynamic vulcanization process, the product manufacturing process is more complex, the product cost is higher, and the odor is stronger. Although TPS has excellent low temperature resistance, low odor, excellent resilience, and good processing performance, its gloss is relatively high and its flow properties are relatively poor. In other words, existing thermoplastic elastomers are difficult to meet the requirements of thin-walled large parts for automotive interiors.

[0004] To simultaneously improve the flowability and gloss of thermoplastic elastomers, the prior art discloses a TPV material composition and its preparation and application. This TPV material composition includes low melt flow index PP resin, high melt flow index PP resin, low Mooney EPDM rubber, high Mooney EPDM rubber, paraffin oil, vulcanizing agent, vulcanization accelerator, antioxidant, light stabilizer and lubricant. By combining the components such as low melt flow index PP resin, high melt flow index PP resin, low viscosity EPDM, and high viscosity EPDM rubber, a TPV material with low gloss is obtained, but the flowability of this material is poor. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and deficiencies of existing thermoplastic elastomers, which are difficult to achieve both high fluidity and low gloss, and to provide a thermoplastic elastomer composition.

[0006] Another object of the present invention is to provide a method for preparing a thermoplastic elastomer composition.

[0007] Another object of the present invention is to provide an application of the above-described thermoplastic elastomer composition in automotive dashboard skin or door panel skin.

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

[0009] This invention protects a thermoplastic elastomer composition, comprising, by weight, the following components:

[0010]

[0011] The PP resin I adopts the ISO 1133-1-2011 standard, and has a melt index of 80-130 g / 10 min at 230℃ and 2.16 kg; the weight-average molecular weight of the SEBS is 80,000-160,000; the TPV includes PP resin II and EPDM.

[0012] The total mass fraction of PP resin I, SEBS and TPV in the thermoplastic elastomer composition is ≥55%; PP resin I can be at least one of homopolymer PP, block copolymer PP or random copolymer PP; the weight average molecular weight of SEBS can be determined by gel chromatography as specified in GB / T21863-2008.

[0013] The PP resin II in the TPV is not particularly limited. For example, the PP resin II may conform to the ISO 1133-1-2011 standard and have a melt index of <2 g / 10 min at 230°C and 2.16 kg. Specifically, it can be at least one of homopolymer PP, block copolymer PP, or random copolymer PP. The EPDM is cross-linked EPDM. The total mass fraction of PP resin II and EPDM relative to the mass fraction of TPV is ≥90%, preferably ≥95%, and more preferably ≥99%.

[0014] Optionally, the mass ratio of SEBS to TPV is (0.7-1.45):1, preferably (0.85-1.4):1, and more preferably (0.9-1.1):1.

[0015] Preferably, the thermoplastic elastomer composition comprises, by weight, the following components:

[0016]

[0017] Preferably, the PP resin I adopts the ISO 1133-1-2011 standard, and has a melt index of 100-120 g / 10 min at 230°C and 2.16 kg.

[0018] Preferably, the weight-average molecular weight of the linear SEBS is 100,000 to 150,000.

[0019] Optionally, the mass ratio of PP resin II to EPDM in the TPV is (10-40):(60-90), preferably (15-35):(65-85), and specifically can be 40:60, 35:65, 25:75, 15:85 or 10:90.

[0020] Specifically, the phase structure size of EPDM in the TPV is 0.5–10 μm, and D 50 The particle size is 1–5 μm. The phase structure size of EPDM can be determined by atomic force electron microscopy (ISO 23729:2022), and its density (D) can be obtained by sieving method in GB / T 21524-2008, which specifies the determination of particle size in inorganic chemical products. 50 The size is 1–5 μm.

[0021] Optionally, the glass fiber powder has a mesh size of 80-1000 mesh and an aspect ratio of (1-10):1. Preferably, the glass fiber powder has a mesh size of 200-600 mesh and an aspect ratio of (3-7):1.

[0022] Specifically, the antioxidant is one or more of antioxidants 1010, 1076, 1790, 168, and DLTP; the light stabilizer is a hindered amine light stabilizer and / or a triazine light stabilizer, for example, a mixture of a hindered amine light stabilizer and a triazine light stabilizer in a weight ratio of 2:1. The hindered amine light stabilizer can be one or more of light stabilizer 622, 944, 3853, or 123; the triazine light stabilizer can be one or more of UV-234, UV-236, or UV-237.

[0023] This invention also protects a method for preparing a thermoplastic elastomer composition, comprising the following steps:

[0024] S1. Mix SEBS with paraffin oil to obtain pre-filled SEBS;

[0025] S2. The pre-filled oil SEBS, PP resin I, TPV, glass fiber powder, antioxidant and light stabilizer in S1 are mixed and then melt-extruded to obtain a thermoplastic elastomer composition.

[0026] Specifically, the pre-filled SEBS from step S1 is left to stand for ≥3 days before step S2 is performed, so that the paraffin oil is fully adsorbed by the SEBS to reduce the viscosity of the SEBS. An oil filling machine can be used to mix the SEBS and paraffin oil, with the screw speed of the oil filling machine being 40-80 r / min and the mixing temperature being 40-80℃.

[0027] In step S2, a twin-screw extruder is used to melt-extrude and granulate the components. Optionally, the twin-screw extruder has a screw length-to-diameter ratio ≥ 56:1, a screw speed of 300–450 r / min, and a melt mixing temperature of 160–200℃. Preferably, in S2, water can be injected into the 9th or 10th section of the twin-screw extruder barrel, with the water injection weight being 5–10% of the total weight of the formulation materials. A vacuum is drawn in the 13th section of the twin-screw extruder barrel, with a vacuum degree ≤ 0.09 MPa.

[0028] The TPV in step S2 comprises PP resin II and EPDM, and can be prepared by the following method: PP resin II, EPDM, and crosslinking agent (bis(2,5-diphenyl)peroxide) are mixed evenly, and then melt-extruded to obtain the TPV. Specifically, a twin-screw extruder can be used for melt extrusion, wherein the temperature of the first zone of the twin-screw extruder is 100–140°C, the temperature of the second zone is 140–160°C, the temperature of the third zone is 180–200°C, and the temperature of the fourth to fourteenth zones is 200°C.

[0029] The crosslinking agent promotes the crosslinking of EPDM and its uniform dispersion in PP resin II, achieving a good phase structure and good phase size distribution. Optionally, the PP resin II is a low melt index homopolymer polypropylene with a melt index <2 g / 10 min (230℃, 2.16 kg); the Mooney viscosity (ML125℃1+4) of EPDM is 60-75.

[0030] The application of the above-mentioned thermoplastic elastomer composition in the dashboard or door panel skin of automobiles is also within the scope of protection of this invention.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] The thermoplastic elastomer composition of the present invention combines PP resin I with a specific melt index, SEBS with a specific weight-average molecular weight, and TPV to maintain good flowability of the composition, thereby enabling the thermoplastic elastomer composition to have both high flowability and low gloss, as well as excellent high temperature resistance. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0034] 1. Raw materials and reagents

[0035] (1) PP-1, grade PP H9018, manufactured by Lanzhou Petrochemical, has a melt index of 45 g / 10 min at 230℃ and 2.16 kg.

[0036] PP-2, grade PP EP648U, manufactured by CNOOC Shell, has a melt flow index of 65 g / 10 min at 230℃ and 2.16 kg.

[0037] PP-3, grade PP K7100, manufactured by Yanshan Petrochemical, has a melt flow index of 100g / 10min at 230℃ and 2.16kg.

[0038] PP-4, grade PP H7912, manufactured by Basel, has a melt index of 1200 g / 10 min at 230°C and 2.16 kg.

[0039] (2) SEBS rubber 1 (SEBS-1), grade YH-501, manufactured by Yueyang Petrochemical, with a weight-average molecular weight of 70,000;

[0040] SEBS rubber 2 (SEBS-2), grade YH-502, manufactured by Yueyang Petrochemical, has a weight-average molecular weight of 100,000;

[0041] SEBS rubber 3 (SEBS-3), grade Globapprene 7554, manufactured by Li Changrong, with a weight-average molecular weight of 150,000;

[0042] SEBS rubber 4 (SEBS-4), grade SEBS 9551, manufactured by Li Changrong, has a weight-average molecular weight of 200,000.

[0043] (3) Paraffin oil, brand name KP6030, manufactured by Karamay.

[0044] (4) The antioxidant is obtained by compounding antioxidant 1076 and antioxidant 168 in a mass ratio of 1:2, and the light stabilizer is obtained by compounding light stabilizer 944 and light stabilizer UV-234 in a mass ratio of 3:2;

[0045] Glass fiber powder, antioxidant 1076, antioxidant 168, light stabilizer 944, and light stabilizer UV-234 are all commercially available.

[0046] (5) TPV can be prepared by the following methods:

[0047] PP resin II, EPDM, and crosslinking agent (bis(2,5-diphenyl) peroxide, with a mass fraction of 0.5% to 1.5% relative to EPDM) are mixed evenly and then melt-extruded in a twin-screw extruder to obtain TPV. The twin-screw extruder has a screw length-to-diameter ratio of 56:1 or greater, a screw speed of 500 to 600 r / min, a zone temperature of 100 to 140℃, a zone temperature of 140 to 160℃, a zone temperature of 180 to 200℃, and a zone temperature of 200℃ for zones four to fourteen.

[0048] Among them, the melt index of the above-mentioned PP resin II is 1g / 10min (230℃, 2.16kg), the grade is PP K1001, and the manufacturer is Yanshan Petrochemical; the Mooney viscosity (ML125℃1+4) of EPDM is 70, the grade is 3080P, and the manufacturer is Jilin Petrochemical.

[0049] Table 1 Different TPVs

[0050]

[0051] 2. The thermoplastic elastomer compositions of the various embodiments and comparative examples of the present invention were prepared by the following method:

[0052] S1. Mix SEBS with paraffin oil to obtain pre-filled SEBS;

[0053] S2. After the pre-charged oil SEBS in S1 is left to stand for 3 days, it is mixed with PP resin I, TPV, glass fiber powder, antioxidant and light stabilizer, and then added to a twin-screw extruder for melt extrusion to obtain a thermoplastic elastomer composition; wherein, the screw length-to-diameter ratio of the twin-screw extruder is ≥56:1, the screw speed is 300~400r / min, and the melt mixing temperature is 160~200℃.

[0054] 3. Performance Testing

[0055] The spiral length was determined using an injection molding machine and a spiral mold. The injection temperature was 230℃, the injection pressure was 75%, the injection speed was 70%, and the mold temperature was 40℃.

[0056] Gloss was tested according to ASTM D523 standard at a test angle of 60°.

[0057] Examples 1-11 and Comparative Examples 1-8

[0058] The weight parts of each component in the thermoplastic elastomer compositions of Examples 1 to 11 are shown in Table 2.

[0059] Table 2 shows the weight parts of each component in the thermoplastic elastomer compositions of Examples 1-11.

[0060]

[0061] Table 3 shows the weight parts of each component in the thermoplastic elastomer compositions of Comparative Examples 1–8.

[0062]

[0063]

[0064] The performance test results of the thermoplastic elastomer compositions in each embodiment and comparative example according to the methods mentioned above are shown in Table 4.

[0065] Table 4 Test results for each embodiment and comparative example

[0066]

[0067] As shown in Table 4, the helix length of the thermoplastic elastomer compositions in Examples 1-11 is ≥70cm, and their room temperature gloss is ≤1.4, indicating that the thermoplastic elastomer compositions of the present invention possess both high fluidity and low gloss. Furthermore, the gloss of the thermoplastic elastomer compositions remains below 1.6 after aging at 135℃ for 24h, further demonstrating that the thermoplastic elastomer compositions of the present invention not only possess high fluidity and low gloss, but also exhibit excellent high-temperature resistance, enabling them to maintain low gloss for extended periods during practical applications and achieving good low-gloss stability.

[0068] Examples 1-2 and Comparative Examples 1-2 show that the flowability of the thermoplastic elastomer composition increases with the increase of the PP melt index, but its gloss first decreases and then increases with the increase of the PP melt index. Similarly, Examples 1, 3, and Comparative Examples 3-4 show that the flowability of the thermoplastic elastomer composition decreases with the increase of the SEBS weight-average molecular weight, but its gloss first decreases and then increases with the increase of the SEBS weight-average molecular weight. That is, the flowability and gloss of the thermoplastic elastomer composition are jointly affected by the PP resin melt index and the SEBS weight-average molecular weight. Only when the melt index or weight-average molecular weight of both are within a specific range can the thermoplastic elastomer composition simultaneously possess good flowability and low gloss. Furthermore, Comparative Examples 5 and 6, and Comparative Examples 7 and 8 show that when the amount of SEBS added is too high or too low, or the amount of TPV added is too high or too low, it is impossible to obtain a thermoplastic elastomer composition that combines high flowability and low gloss.

[0069] 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 will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all possible implementations 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 composition, characterized by, By weight, it includes the following components: PP resin I20~35 parts, SEBS 25~40 portions, TPV 25~40 units, 5-15 parts of glass fiber powder 25-40 parts of paraffin oil Antioxidant 0-0.5 parts, Light stabilizer 0~0.6 parts, The PP resin I adopts the ISO 1133-1-2011 standard, and has a melt index of 80~130g / 10min at 230℃ and 2.16kg; the SEBS has a weight-average molecular weight of 80,000~160,000; the TPV includes PP resin II and EPDM. The glass fiber powder has a mesh size of 80-1000 mesh.

2. The thermoplastic elastomer composition according to claim 1, characterized in that, The PP resin I adopts the ISO1133-1-2011 standard, and its melt index is 100~120 g / 10min under the conditions of 230℃ and 2.16kg.

3. The thermoplastic elastomer composition according to claim 1, wherein The linear SEBS has a weight-average molecular weight of 100,000 to 150,000.

4. The thermoplastic elastomer composition according to claim 1, characterized in that, The mass ratio of PP resin II to EPDM in the TPV is (10~40):(60~90).

5. The thermoplastic elastomer composition according to claim 1, characterized in that, The phase structure size of the EPDM in the TPV is 0.5-10 μm, and the D 50 is 1-5 μm.

6. The thermoplastic elastomer composition according to claim 1, characterized in that, The glass fiber powder has a mesh size of 200-600.

7. The thermoplastic elastomer composition according to claim 1, characterized in that, The antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 1790, antioxidant 168 and antioxidant DLTP; the light stabilizer is a hindered amine light stabilizer and / or a triazine light stabilizer.

8. A method for preparing the thermoplastic elastomer composition according to any one of claims 1 to 7, comprising the following steps: S1. Mix SEBS with paraffin oil to obtain pre-filled SEBS; S2. The pre-filled oil SEBS, PP resin I, TPV, glass fiber powder, antioxidant and light stabilizer in S1 are mixed and then melt-extruded to obtain a thermoplastic elastomer composition.

9. The use of the thermoplastic elastomer composition according to any one of claims 1 to 7 in the dashboard skin or door panel skin of an automobile.

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