TPV (thermoplastic vulcanizate) modified polypropylene micro-foaming composite material and preparation method thereof

Abstract

The invention discloses a TPV (thermoplastic vulcanizate) modified polypropylene micro-foaming composite material and a preparation method thereof, and belongs to the field of blending modification processing of high polymer materials. The micro-foaming composite material comprises the following raw materials in percentage by mass: 50%-65% of polypropylene resin, 10%-25% of thermoplastic vulcanizate, 0%-10% of mineral powder, 2%-4% of a foaming agent, 0%-0.5% of a nucleating agent, 0.5%-1.5% of a deodorant and 0.5%-2.5% of a processing aid B. The prepared TPV modified polypropylene micro-foaming composite material has good appearance, a uniform foaming layer and low odor, the comprehensive weight reduction can reach 20%-30%, and the TPV modified polypropylene micro-foaming composite material can be applied to parts such as automobile door panels, stand columns and decorative plates.

Description

Technical Field

[0001] The invention relates to the field of polymer material blending and modification processing, and in particular to a TPV-modified polypropylene micro-foamed composite material and a preparation method thereof. Background Art

[0002] In recent years, with the development of the automotive industry and the increasing requirements for low-carbon and environmental protection, the application of lightweight parts has become more and more extensive. Among the lightweight methods such as thin-walling, replacing steel with plastic, and micro-foaming, since thin-walling has high requirements for material properties and the application of replacing steel with plastic is limited, reducing the weight of parts through micro-foaming technology has received widespread attention.

[0003] Micro-foamed polypropylene composite materials are made by mixing polypropylene composite materials with foaming agents in a certain proportion to achieve injection molding foaming. Generally, the open mold foaming process is used to produce plastic parts. Due to its crystallization properties, it is difficult for polypropylene resin to achieve an ideal foaming effect. It is mainly achieved by adding nucleating agents, filling and other methods to promote melt nucleation, thereby improving melt strength, obtaining uniform bubbles in the product, and obtaining a good appearance.

[0004] Patent CN201610875485.8 provides a low-shrinkage micro-foamed polypropylene material. The addition of low-shrinkage masterbatch reduces the shrinkage rate of the material and gives the material a certain dimensional stability. However, the low-shrinkage material cannot meet the application requirements of most automotive interior parts, resulting in limited application. Patent CN202110969752.9 uses copolymerized polyamide resin and nano-metal oxide to modify polypropylene materials, and prepares automotive interior parts by adding chemical foaming agents and secondary mold injection molding process, providing a new idea for high-performance micro-foamed polypropylene materials and their components.

[0005] The present invention provides a TPV-modified polypropylene micro-foam composite material, which improves the comprehensive mechanical properties of polypropylene resin by TPV blending modification and modified mineral powder filling, and provides foaming hole support points of the polypropylene composite material by chemical cross-linking bonds in the TPV component to improve the appearance and weight reduction ratio of the product, and finally obtains a product with excellent appearance and high weight reduction ratio.

[0006] The difficulties in the molding process of micro-foamed polypropylene composite materials are the formation and uniformity of bubbles, the appearance of the product, the foaming ratio, etc. Polypropylene materials have a certain crystallization rate, and the interaction between the molecular chains in the crystal area is strong. The gas generated during foaming is not easy to diffuse to the crystal area, which affects the formation and stability of bubbles, and then causes defects such as silver wire and pits in the product appearance. However, higher molding temperatures will cause the foaming agent to decompose prematurely, so that the foaming agent cannot achieve the corresponding foaming effect. Therefore, it is necessary to improve the crystallization and melt strength of polypropylene materials, foaming process, injection molding temperature, etc. to obtain products with excellent performance and appearance. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a TPV-modified polypropylene micro-foam composite material and a preparation method thereof.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] The first aspect of the present invention relates to a thermoplastic vulcanizate, comprising the following raw materials in percentage by mass:

[0010]

[0011] Optionally, the processing aid A includes an antioxidant, an ultraviolet absorber, an anti-aging agent and a lubricant.

[0012] The second aspect of the present invention relates to a TPV-modified polypropylene micro-foam composite material, comprising:

[0013]

[0014] Thermoplastic vulcanizate 10-25% of the above

[0015] Foaming agent 2-4%.

[0016] The polypropylene has a melt flow rate of 30-100 g / min at 230° C. and 2.16 kg, and has a hyperbranched structure in the molecular chain.

[0017] The mineral powder is modified talc powder, which is talc powder treated with a silane coupling agent and has a mesh size of 2000 or more. The specific modification method is as follows: silane coupling agent: talc powder = 1:50 to 1:25 mass percentage is added to a high-speed mixer, and at the same time, one of calcium stearate and zinc stearate is added at a mass percentage of 4% to 5%, and mixed at 2000r / min for more than 10 minutes.

[0018] The nucleating agent is an aromatic phosphate salt nucleating agent, and the processing aids are an antioxidant, a light stabilizer and a lubricant.

[0019] The foaming agent is a foaming masterbatch of a PE carrier, and its foaming agent component is one of NaHCO3 or azodicarbonamide. The preparation method is as follows: (1) adding 95-95% by mass of PE resin and 3%-5% of foaming agent into an internal mixer at a temperature of 110°C-130°C, and the speed of the internal mixer is 50-55r / min; (2) after underwater circulation pelletization, drying at 80°C for standby use.

[0020] The vulcanizing agent is one of DCP and BIBP, and the vulcanization accelerator is TAIC.

[0021] The third aspect of the present invention relates to a method for preparing a TPV-modified polypropylene micro-foam composite material, comprising the following steps:

[0022] Add polypropylene, EPDM rubber, SEBS and plasticizer into an internal mixer, put the product into an open mixer, grind it through an open mixer, crush it and add it back into the internal mixer, then add processing aid A and accelerator; crush the obtained mixed rubber and add it into a twin-screw extruder together with a vulcanizer for granulation to obtain a thermoplastic vulcanizate;

[0023] Putting polypropylene and thermoplastic vulcanizate into an extruder, and obtaining a TPV-modified polypropylene composite material through plasticizing, blending, distributing, cooling, drying, and pelletizing;

[0024] The TPV-modified polypropylene composite material is mixed with a foaming agent and then added into an injection molding machine for molding to obtain a TPV-modified polypropylene micro-foamed composite material.

[0025] More specifically, the above method may include the following steps:

[0026] 1) Weigh the raw materials according to the formula ratio, and put the remaining raw materials except the foaming agent into a high-speed mixing pot and mix for 6-10 minutes to prepare a premix.

[0027] 2) Adding the premix to a co-rotating meshing twin-screw extruder, plasticizing, blending, distributing, cooling, drying, and pelletizing, finally obtaining a TPV-modified polypropylene composite material, wherein the extrusion temperature of the twin-screw extruder is 190° C.-210° C., the screw speed is 500-600 r / min, and the vacuum degree is above -0.08 MPa.

[0028] 3) When injection molding, the TPV modified polypropylene composite material obtained above is mixed with a foaming agent and then added into an injection molding machine at an injection molding temperature of 190° C.-210° C.

[0029] Beneficial effects of the present invention:

[0030] (1) The polypropylene composite material obtained by the method provided by the present invention has excellent comprehensive mechanical properties, and can achieve the requirements of automobile parts for material properties under the premise of reducing the weight of automobile parts;

[0031] (2) The polypropylene composite material obtained in the present invention is used to obtain automobile parts with significantly reduced weight through chemical foaming and injection molding secondary mold opening process, and the foam cells in the middle of the cross section of the part are dense and uniform.

[0032] (3) The use of TPV-modified polypropylene matrix in the present invention can improve the mechanical properties of the matrix while providing the matrix with chemical cross-linking points to support the pores obtained by chemical foaming, thereby reducing the weight of automobile parts while achieving excellent appearance. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The reagents or raw material models and manufacturers mentioned in the following examples and comparative examples are as follows:

[0035] Polypropylene resin 1 is PP BX3800 (Sino-Korea Petrochemical), polypropylene resin 2 is PP LCB-IPC (Yanshan Petrochemical), polypropylene resin 3 is PP BX3900 (Sino-Korea Petrochemical), polypropylene resin 4 is PP BX3920 (Sino-Korea Petrochemical), polypropylene resin 5 is PP K9017H (Sino-Korea Petrochemical), and polypropylene resin 6 is PP NS06 (Sino-Korea Petrochemical). Polypropylene resin 1, polypropylene resin 5, and polypropylene resin 6 can be used for the preparation of TPV, and their specific combination and mass ratio can be set as: polypropylene resin 1: 10-15%, polypropylene resin 5 or polypropylene resin 6: 20%-30%;

[0036] EPDM 1 is EPDM 3072EPM (Mitsui Chemicals), EPDM 2 is EPDM 3092PM (Sinopec Mitsui), SEBS is SEBS YH-503T (Baling Petrochemical), and elastomer is POE LC565 (SK, South Korea);

[0037] Mineral powder 1 is talcum powder 9276 (Xinda, Liaoning), and mineral powder 2 is talcum powder AHCP250 (Haicheng, Liaoning);

[0038] Foaming agent 1 is NaHCO3 (Aladdin), foaming agent 2 is AC foaming agent (Shenzhen Wansuyuan);

[0039] The plasticizer is No. 10 white oil (Sinopec);

[0040] The vulcanizing agent was vulcanizing agent DCP (Akzo Nobel), and the accelerator was TAIC (Akzo Nobel);

[0041] Processing aid B includes:

[0042] Antioxidant 1010 (BASF SE),

[0043] Antioxidant 168 (BASF SE),

[0044] Light stabilizer 3808PP5 (U.S. Cytec Chemical),

[0045] Nucleating agent NA-11 (Japan Aidico),

[0046] Deodorant JH-200CX (Ningbo Jiahe),

[0047] Lubricant, silicone masterbatch HG-600S (Zhejiang Jiahua);

[0048] All materials are commercially available conventional products.

[0049] The above reagents are only for illustrating the sources and components of the reagents used in the experiments of the present invention so as to fully disclose the information, and do not mean that the present invention cannot be realized by using other similar reagents or reagents provided by other suppliers.

[0050] A method for preparing a TPV-modified polypropylene micro-foam composite material comprises the following steps:

[0051] 1) Add polypropylene, EPDM rubber, SEBS and plasticizer to an internal mixer in sequence, with the temperature of the internal mixer being 180-190°C; (2) The mixed rubber in (1) is thinly kneaded in an open mixer, crushed and added back to the internal mixer, and then processing aid A and accelerator are added in sequence; (3)

[0052] The rubber compound obtained in (2) is crushed and added to a twin-screw extruder together with a vulcanizing agent for granulation at an extrusion temperature of 160-170°C. After underwater circulation granulation, it is dried at 80°C for later use. The processing aid A includes antioxidant 1790, antioxidant DSTP, ultraviolet absorber UV-P, antioxidant RD and lubricant zinc stearate.

[0053] In the above step 1), the polypropylene uses polypropylene resin 1 and polypropylene resin 6, and the mass ratio of the above components can be set to:

[0054] Polypropylene resin 1 10%,

[0055] Polypropylene resin 6 25%

[0056] EPDM 45%,

[0057] SEBS 5%,

[0058] Plasticizer 5%,

[0059] Vulcanizing agent 0.8%,

[0060] Accelerator 0.5%,

[0061] Processing aid A 1.5%.

[0062] 2) Weigh the raw materials according to the formula ratio in Table 1, and put the remaining raw materials except the foaming agent into a high-speed mixing pot and mix for 6-10 minutes to prepare a premix.

[0063] 3) adding the premix to a co-rotating meshing twin-screw extruder, and finally obtaining a TPV-modified polypropylene composite material through plasticizing, blending, distribution, cooling, drying, and pelletizing, wherein the extrusion temperature of the twin-screw extruder is 190° C.-210° C., the screw speed is 500-600 r / min, and the vacuum degree is above -0.08 MPa.

[0064] When injection molding, the TPV modified polypropylene composite material obtained above is blended with the foaming agent according to Table 1 and then added into the injection molding machine. The injection molding temperature is 190°C-210°C.

[0065] The material proportions used in each embodiment and comparative example are shown in Table 1 below:

[0066] The material ratio used in the example is shown in Table 1 below:

[0067] Table 1 Material ratios used in various embodiments and comparative examples

[0068]

[0069]

[0070] The performance tests and test conditions of the modified polypropylene materials (before foaming) prepared in the above embodiments and comparative examples are as follows: the density of the material is tested according to ISO 1183-1 standard, the test condition is 23° C., and an alcohol density tester is used; the tensile test is tested according to ISO 527-2 standard, the spline shape is a dumbbell spline, and the test speed is 50 mm / min; the bending performance is tested according to ISO 178 standard, wherein the test speed is 2 mm / min, the spline shape is a rectangular spline, and the spline size is 80 mm×10 mm×4 mm; the cantilever beam notched impact is tested according to ISO 180 standard, the notch depth is 2 mm, the spline shape is a rectangular spline, and the spline size is 80 mm×10 mm×4 mm; the melt index is tested according to ISO 1133-1 / 2 standard, and the test conditions are 230° C., 2.16 kg.

[0071] The product properties of Examples 1-6 and Comparative Examples 1-5 are shown in Table 2.

[0072] Table 2 Test results of product mechanical properties and weight reduction ratio

[0073]

[0074]

[0075] According to the data in Table 2, it can be seen that the use of polypropylene resin with a branched structure and TPV modification can greatly improve the melt strength and mechanical properties of polypropylene materials, and a uniform pore structure and excellent weight loss effect can be obtained in the obtained micro-foamed product. This is mainly because the polypropylene resin with a branched structure increases the melt viscosity of the composite material, so that the material will not have pore rupture during the foaming process; TPV-modified polypropylene resin can improve the toughness of the composite material without reducing the strength of the material, and the cross-linking structure in TPV gives the composite material chemical cross-linking points, which provides support for the formation of pores; modified mineral powder can improve the processing process and improve the dispersion of powder in the resin matrix, thereby improving the material performance; nucleating agents will increase the crystallization temperature and number of crystal nuclei of the melt, give the material physical cross-linking points, improve the mechanical properties of the material, and provide a support structure for the pores.

[0076] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0077] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A thermoplastic vulcanizate, characterized in that: The following raw materials are included in mass percentage:

2. The thermoplastic vulcanizate according to claim 1, characterized in that The processing aid A includes: antioxidant, ultraviolet absorber, anti-aging agent and lubricant.

3. The thermoplastic vulcanizate according to claim 1, characterized in that The vulcanizing agent is vulcanizing agent DCP or BIBP; the accelerator is TAIC; and the plasticizer is white oil.

4. A TPV modified polypropylene micro-foam composite material, characterized in that: include: Polypropylene 50-65% 10-25% of the thermoplastic vulcanizate according to any one of claims 1 to 3 Foaming agent 2-4%.

5. The TPV modified polypropylene micro-foam composite material according to claim 4, characterized in that: The following ingredients are also included:

6. The TPV modified polypropylene micro-foam composite material according to claim 5, characterized in that: The mineral powder is talcum powder modified by a silane coupling agent; and the nucleating agent is an aromatic phosphate salt nucleating agent.

7. The TPV-modified polypropylene micro-foam composite material according to claim 4, characterized in that: The foaming agent is a foaming masterbatch of a PE carrier.

8. The TPV modified polypropylene micro-foam composite material according to claim 5, characterized in that: The processing aid B includes one or more of an antioxidant, a light stabilizer, a lubricant, and a deodorant.

9. The TPV-modified polypropylene micro-foam composite material according to claim 8, characterized in that: The antioxidant is antioxidant 1010 and / or antioxidant 168.

10. A method for preparing a TPV-modified polypropylene micro-foam composite material, characterized in that: The following steps are involved: Add polypropylene, EPDM rubber, SEBS and plasticizer into an internal mixer, put the product into an open mixer, grind it through an open mixer, crush it and add it back into the internal mixer, then add processing aid A and accelerator; crush the obtained mixed rubber and add it into a twin-screw extruder together with a vulcanizer for granulation to obtain a thermoplastic vulcanizate; Putting polypropylene and thermoplastic vulcanizate into an extruder, and obtaining a TPV-modified polypropylene composite material through plasticizing, blending, distributing, cooling, drying, and pelletizing; The TPV-modified polypropylene composite material is mixed with a foaming agent and then added into an injection molding machine for molding to obtain a TPV-modified polypropylene micro-foamed composite material.

Images