Scratch-resistant blow molding grade TPO (thermoplastic polyolefin) elastomer with smooth hand feeling and preparation method of scratch-resistant blow molding grade TPO elastomer

Abstract

The invention discloses a scratch-resistant blow molding grade TPO (thermoplastic polyolefin) elastomer with smooth hand feeling and a preparation method of the scratch-resistant blow molding grade TPO elastomer. The TPO elastomer is prepared from the following components in parts by weight: 40 to 60 parts of polypropylene, 20 to 35 parts of ethylene propylene rubber, 5 to 15 parts of thermoplastic polyurethane, 2 to 5 parts of nano aluminum oxide, 1 to 3 parts of silicone master batch, 0.1 to 0.3 part of dynamic vulcanizing agent, 2 to 4 parts of compatilizer, 0.2 to 0.5 part of antioxidant and 0.1 to 0.3 part of light stabilizer. The preparation method comprises the following steps: carrying out surface modification on the nano aluminum oxide, pre-mixing the components, and carrying out dynamic vulcanization blending and granulation at a specific temperature and a specific rotating speed by using a double-screw extruder. Through multi-component cooperation and a dynamic vulcanization process, the material has excellent surface smooth hand feeling (the static friction coefficient is less than or equal to 0.4) and scratch resistance (the pencil hardness is greater than or equal to 3H) while keeping high toughness and high elasticity, and is particularly suitable for blow molding products with high requirements on touch feeling and surface durability, such as automotive interiors and household appliance shells.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a scratch-resistant blow molding grade TPO elastomer with smooth hand feeling and a preparation method thereof, which is suitable for automotive interior parts, household appliance shells and other blow molding products with high requirements for touch and surface durability. BACKGROUND

[0002] Thermoplastic polyolefin is a high polymer material formed by blending elastomers such as polypropylene, ethylene-propylene rubber or terpolymer ethylene-propylene rubber with polyolefin, which has both flexibility of rubber and processability of plastic and is widely used in automotive interior and exterior, industrial products and other fields. However, the traditional blow molding grade TPO has two key defects: first, the surface friction coefficient is high, the touch is dry and rough, and the user experience is poor; second, the scratch resistance is insufficient, and the surface is easily damaged under external force, affecting the appearance and service life.

[0003] In the existing improvement scheme, the smoothness is often improved by adding silicone oil, but the silicone oil is easy to migrate to the surface to cause pollution, and the smoothness effect decreases after long-term use; the scratch resistance depends on the addition of nano silicon dioxide, polytetrafluoroethylene and the like, but high filling amount will significantly reduce the toughness of the material, and the nano silicon dioxide is easy to agglomerate, which damages the surface smoothness. In addition, the blow molding process has strict requirements on the melt strength, flowability and processing stability of the material, and the conventional modification method is difficult to meet multiple requirements.

[0004] Therefore, it is of important engineering value to develop a blow molding grade TPO elastomer with smooth hand feeling and scratch resistance by synergistic effect of multiple components (elastomer phase state regulation, interface compatibility optimization, functional filler dispersion) and precise process control (such as dynamic vulcanization, melt treatment). SUMMARY

[0005] The present application aims to provide a scratch-resistant blow molding grade TPO elastomer with smooth hand feeling and a preparation method thereof, which solves the problems of poor touch, easy scratching and insufficient processability of the existing materials.

[0006] The technical scheme provided by the present application is as follows: a scratch-resistant blow molding grade TPO elastomer with smooth hand feeling, which comprises the following components by weight: Polypropylene resin: 40-60 parts; Ethylene-propylene rubber: 20-35 parts; Thermoplastic polyurethane: 5-15 parts; Silicone master batch: 1-3 parts; Nano alumina: 2-5 parts; Dynamic vulcanizing agent: 0.1-0.3 parts; Compatibility agent: 2-4 parts; Antioxidant: 0.2-0.5 parts; Light stabilizer: 0.1-0.3 parts.

[0007] A scratch-resistant blow molding grade TPO elastomer with a smooth hand feeling as described above, the melt flow rate of the polypropylene resin is 5-15 g / 10 min (230℃, 2.16 kg), selected from homopolymer polypropylene, copolymer polypropylene or a mixture thereof.

[0008] A scratch-resistant blow molding grade TPO elastomer with a smooth hand feeling as described above, the Mooney viscosity of the ethylene-propylene rubber is 40-60 (ML 125℃), the content of the third monomer ENB is 4-8%.

[0009] A scratch-resistant blow molding grade TPO elastomer with a smooth hand feeling as described above, the hardness of the thermoplastic polyurethane is 80A-90A, and the molecular weight is 20000-50000.

[0010] A scratch-resistant blow molding grade TPO elastomer with a smooth hand feeling as described above, the content of polydimethylsiloxane in the silicone masterbatch is 10-15%.

[0011] A scratch-resistant blow molding grade TPO elastomer with a smooth hand feeling as described above, the dynamic vulcanizing agent is peroxide DCP.

[0012] A scratch-resistant blow molding grade TPO elastomer with a smooth hand feeling as described above, the compatibilizer is maleic anhydride grafted polypropylene, and the grafting rate is 0.8-1.5%.

[0013] The preparation method of the TPO elastomer as described above comprises the following steps: S1, raw material pretreatment: mixing nano alumina and silane coupling agent according to the mass ratio of 100:1 to 100:3, reacting at 80-100℃ for 30-40 minutes to obtain surface modified nano alumina; the rest of the raw materials are dried; S2, preparation of premix: after drying, the polypropylene, ethylene-propylene rubber, thermoplastic polyurethane, compatibilizer, antioxidant, light stabilizer are added into a high-speed mixer and mixed at 500-600 rpm for 5-8 minutes, then the surface modified nano alumina, silicone masterbatch and dynamic vulcanizing agent are added and continue to mix for 3-5 minutes to obtain the premix; S3, dynamic vulcanization blending: the premix is put into a twin-screw extruder, and melt blending, dynamic vulcanization and granulation are carried out at a temperature range of 160-210℃ and a screw speed of 300-400 rpm.

[0014] Compared with the prior art, the present application has the following advantages: 1. Smooth hand feeling benefit: The low surface energy lubricating layer provided by the silicone masterbatch and the micro-convex structure of the nano-alumina synergistically work together to reduce the static friction coefficient of the material to 0.3-0.4, and the touch is delicate and smooth, close to the touch experience of silicone or soft PVC; 2. Outstanding scratch resistance: The hard particles of nano-alumina resist external scratches, and the surface cross-linked structure inhibits silicone migration, with a pencil hardness of 3H-4H, and a surface color difference E≤1.0 after random scratching, significantly improving the durability; 3. Balanced comprehensive performance: Through TPU toughening and dynamic vulcanization cross-linking, the elongation at break of the material is ≥300%, balancing flexibility, strength and surface functionality. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0016] Embodiment 1: The present embodiment provides a TPO elastomer, The raw material composition (by weight) is: PP (MFR: 10 g / 10 min): 50 parts EPDM (Mooney viscosity 50): 30 parts TPU (hardness 85A): 10 parts Silicone masterbatch (12% siloxane): 2 parts Nano-alumina: 3 parts DCP: 0.2 parts Grafted PP (compatibilizer): 3 parts Antioxidant: 0.3 parts Light stabilizer: 0.2 parts The preparation method is: S1, raw material pretreatment: mix the nano-alumina and silane coupling agent KH550 in a mass ratio of 100:1-100:3, place in a mixing machine and stir for 10-15 min, heat to 80-100°C and react for 30-40 min, so that the coupling agent coats the surface of the nano-particles, obtaining surface-modified nano-alumina; the other raw materials are dried to remove water; S2, premix preparation: add the dried PP, EPDM, TPU, compatibilizer, antioxidant, light stabilizer into a high-speed mixer, mix at a speed of 500-600 rpm for 5-8 min, then add the surface-modified alumina, silicone masterbatch and dynamic vulcanizing agent, continue to mix for 3-5 min, to obtain a uniform premix; S3, dynamic vulcanization blending: put the premix into a twin-screw extruder and melt blend according to the following process parameters: Zone 1 temperature: 160-170℃ Zone 2-4 temperature: 180-200℃ Zone 5-7 temperature: 200-210℃ Zone 8-head temperature: 190-210℃ Screw speed: 300-400rpm After shearing and melting in the screw, the dynamic vulcanizing agent decomposes to initiate mild crosslinking of EPDM and part of PP, while the nano-alumina and silicone masterbatch are uniformly dispersed, obtaining TPO elastomer granules.

[0017] Material test results: static friction coefficient 0.38, pencil hardness 3H, MFR 3.2g / 10min, color difference ΔE=0.8 after scratching, smooth surface of blow molding products without defects.

[0018] The material composition and preparation of the TPO elastomer of this embodiment have the characteristics of a multiphase synergistic system design, which is specifically embodied in: Basic elastic skeleton: PP provides rigid support and processing fluidity, and EPDM gives the material flexibility and resilience, and the two are blended to form an island structure. TPU as a toughening phase, improves the interfacial bonding of EPDM and PP through molecular chain entanglement, and its flexible segment can buffer external impact to avoid the increase of brittleness caused by hard fillers.

[0019] Smooth functional layer: low molecular weight polydimethylsiloxane in silicone masterbatch migrates to the material surface during melt processing, forming a continuous lubricating film; nano-alumina treated with silane coupling agent is uniformly dispersed in the matrix, and its high-hardness particles are embedded in the surface micro-convex structure, which can avoid migration and precipitation; Dynamic vulcanization process optimization: dynamic vulcanization blending is carried out using a twin-screw extruder, with temperature controlled at 180-210℃ and screw speed at 300-400rpm. Dynamic vulcanizing agent DCP decomposes to produce free radicals at high temperature, initiating mild crosslinking of EPDM and part of PP, making the particle size of EPDM dispersed phase 0.5-2 microns, thereby reducing stress concentration points and improving the overall toughness of the material; at the same time, the correlation structure limits the excessive migration of silicone molecules, ensuring the durability of the smooth effect.

[0020] Blow molding process adaptability regulation: by adjusting the ratio of TPU to PP, the melt flow rate of the material is controlled at 1.5g / 10min, which not only meets the good flowability required for blow molding, but also ensures sufficient melt strength; the addition amount of nano-alumina is optimized, and the surface roughness of the material is controlled at 0.2-0.5 microns, which not only forms an effective anti-skid layer, but also avoids surface defects caused by particle aggregation.

[0021] Example 2: This example provides a TPO elastomer, the raw material composition (parts by weight) is: PP (MFR: 10 g / 10 min): 55 parts EPDM (Mooney viscosity 50): 32 parts Silicone masterbatch (12% siloxane): 3 parts DCP: 0.2 parts Grafted PP: 3 parts Antioxidant: 0.3 parts Light stabilizer: 0.2 parts No TPU and nano-alumina is added Material test results: static friction coefficient 0.52, pencil hardness 2H, color difference ΔE = 2.1 after scratching, the surface is obviously whitened, and the performance is significantly reduced.

[0022] The above examples show that the present application successfully realizes the comprehensive improvement of TPO elastomer in smooth feel, scratch resistance and processability through multi-component synergy and process optimization.

[0023] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A scratch resistant blow molded TPO elastomer with a slipperier feel, characterized in that, The composition comprises the following components by weight parts: Polypropylene resin: 40-60 parts; Ethylene-propylene rubber: 20-35 parts; Thermoplastic polyurethane: 5-15 parts; Silicone masterbatch: 1-3 parts; Nano-alumina: 2-5 parts; Dynamic vulcanizing agent: 0.1-0.3 parts; Compatibilizer: 2-4 parts; Antioxidant: 0.2-0.5 parts; Light stabilizer: 0.1-0.3 parts.

2. A scratch resistant blow molded TPO elastomer with a smooth touch according to claim 1, characterized in that, The melt flow rate of the polypropylene resin is 5-15 g / 10 min (230℃, 2.16 kg), selected from homopolymer polypropylene, copolymer polypropylene or a mixture thereof.

3. A scratch resistant blow molded TPO elastomer with a slipperier feel according to claim 1, characterized in that, The Mooney viscosity of the ethylene-propylene rubber is 40-60 (ML 125℃), and the content of the third monomer ENB is 4-8%.

4. A scratch resistant blow molded TPO elastomer with a slipperier feel according to claim 1, characterized in that, The hardness of the thermoplastic polyurethane is 80A-90A, and the molecular weight is 20000-50000.

5. A scratch resistant blow molded TPO elastomer with a slipperier feel according to claim 1, wherein, The content of polydimethylsiloxane in the silicone masterbatch is 10-15%.

6. A scratch resistant blow molded TPO elastomer with a slipperier feel according to claim 1, wherein, The dynamic vulcanizing agent is peroxide DCP.

7. A scratch resistant blow molded TPO elastomer with a slipperier feel according to claim 1, wherein, The compatibilizer is maleic anhydride grafted polypropylene with a grafting rate of 0.8-1.5%.

8. A process for the preparation of the TPO elastomer according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: S1, raw material pretreatment: mix nano-alumina and silane coupling agent at a mass ratio of 100:1 to 100:3, react at 80-100℃ for 30-40 minutes to obtain surface-modified nano-alumina; the rest of the raw materials are dried; S2, preparation of premix: add dried polypropylene, ethylene-propylene rubber, thermoplastic polyurethane, compatibilizer, antioxidant, light stabilizer into a high-speed mixer, mix at 500-600 rpm for 5-8 minutes, then add surface-modified nano-alumina, silicone masterbatch and dynamic vulcanizing agent, continue to mix for 3-5 minutes to obtain a premix; S3, dynamic vulcanization blending: put the premix into a twin-screw extruder, melt blend, dynamically vulcanize and granulate at a temperature range of 160-210℃ and a screw speed of 300-400 rpm.