A polypropylene material and its preparation method

Abstract

The present invention relates to a polypropylene material and a preparation method thereof, comprising a polypropylene resin, an inorganic filler, a toughening agent, a compatibilizer and a nucleating agent. By means of a special compatibilizer, the present invention enables the PP resin to have good interfacial affinity with the inorganic filler, and at the same time can be well dispersed and compatible with the PP resin and the toughening agent, and the product has high dimensional stability; in addition, the compatibilizer can reduce the melting point of the PP resin, significantly improve the peel strength between the PP resin and other materials, especially improve the compatibility between the PP resin and the thermoplastic elastomer, and increase the peel strength between the PP resin and the thermoplastic elastomer.

Description

Technical Field

[0001] The present invention belongs to the field of modified plastics, and particularly relates to a polypropylene material and a preparation method thereof. Background Art

[0002] By encapsulating and compounding a thermoplastic elastomer (TPE) with polypropylene through processes such as co-extrusion or two-color injection molding, the soft feeling on the surface of the product can be improved, and performances such as anti-collision, waterproof, anti-slip, shock absorption, and comfort can be enhanced. Due to its excellent characteristics, it is currently widely used in automotive interior and exterior trim parts such as door trim panels, instrument panels, and water cutters and other encapsulated parts.

[0003] However, in the application of parts such as water cutters, due to the long product size and the existence of structures such as corners, the situation of TPE and PP encapsulation cracking easily occurs during the use of the parts. Currently, the main methods to improve the bonding performance of TPE and PP encapsulation are to solve it through the extrusion process or adjust the TPE material, but the optimal solution effect cannot be achieved. It is difficult to improve from the perspective of the PP material, so the service life of the extruded water cutter is greatly limited.

[0004] Patent CN 106497089 A discloses a TPE material for encapsulating a PP skeleton and a preparation method thereof. Through the research on the TPE material formula, a new type of TPE material is proposed. The new material is different from the current TPE materials, with low viscosity, good fluidity, and excellent encapsulation performance with PP materials. However, the PP material used is a common PP material, and the peel strength is still less than 2 N / mm. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a polypropylene material and a preparation method thereof, which solve the problem of low peel strength between PP and other materials, especially the problem of low peel strength between PP and thermoplastic elastomers.

[0006] The present invention provides a polypropylene material, which comprises the following components by weight:

[0007]

[0008] Among them, the compatibilizer is trimethylolpropane triacrylate TMPTA grafted polyolefin thermoplastic elastomer.

[0009] The polypropylene resin is at least one of homopolypropylene and copolymerized polypropylene, and the melt flow rate is 0.5 - 9 g / 10 min. The melt flow rate is detected according to the standard ISO 1133:2005 under the conditions of 230 °C / 2.16 kg. Preferably, the melt flow rate is 0.5 - 5 g / 10 min.

[0010] The inorganic filler is talcum powder with a particle size of 1250 - 5000 mesh, preferably 3000 - 5000 mesh.

[0011] As the mesh number of talcum powder increases, that is, the particle size decreases, the shrinkage rate and post - shrinkage degree of the polypropylene material decrease, thereby reducing the linear expansion coefficient of the material. Compared with calcium carbonate with a spherical structure, talcum powder with a flaky structure has a better nucleation effect. Therefore, at the same content, the linear expansion coefficient of the polypropylene material can be further reduced.

[0012] The toughening agent is one or more of ethylene - octene copolymer, ethylene - propylene - diene monomer rubber, propylene - α - olefin copolymer, and SEBS.

[0013] The trimethylolpropane triacrylate (TMPTA) grafted polyolefin thermoplastic elastomer comprises the following components: polyolefin thermoplastic elastomer, trimethylolpropane triacrylate (TMPTA), and styrene (St); the mass ratio is (2000 - 2500):(60 - 80):(60 - 80); the grafting rate of the trimethylolpropane triacrylate (TMPTA) grafted polyolefin thermoplastic elastomer is 8 - 18%. Preferably, the grafting rate of the trimethylolpropane triacrylate (TMPTA) grafted polyolefin thermoplastic elastomer is 10 - 15%.

[0014] Grafting rate measurement method: Use a Heracus - C.H.N.O.S elemental analyzer to measure the oxygen percentage content of the compatibilizer, and calculate the grafting rate M using the formula: P=(N1 / N2)×oxygen percentage content; M = P / (100 - P). Where N1 is the molecular weight of the reactive monomer and N2 is the molecular weight of oxygen.

[0015] The reason for preferably using a modified grafted polyolefin thermoplastic elastomer with a grafting rate of 10 - 15% as the compatibilizer is that when the grafting rate is less than 10%, the proportion of polar groups in the compatibilizer is relatively small, and the compatibility and mechanical properties of the PP material cannot be effectively improved. When the grafting rate is greater than 15%, the reaction time needs to be increased during the production of the modified grafted polyolefin thermoplastic elastomer, resulting in more side reactions and serious internal cross - linking, thus affecting the reactivity of the compatibilizer with the PP material.

[0016] The polyolefin thermoplastic elastomer is at least one of ethylene - octene copolymer and ethylene - butene copolymer.

[0017] The ethylene - octene copolymer used as the toughening agent and the ethylene - octene copolymer used as the polyolefin thermoplastic elastomer of the compatibilizer can be the same or different, preferably the same ethylene - octene copolymer.

[0018] The nucleating agent is at least one of polypropylene - based nucleating agents, aryl phosphate salt - based nucleating agents, polyethylene - based nucleating agents, and organic salt - based nucleating agents.

[0019] Preferably, the polypropylene resin is 35 - 45 parts; the inorganic filler is 25 - 30 parts; the compatibilizer is 8 - 10 parts.

[0020] The present invention also provides a preparation method of a high-performance extruded coated skeleton polypropylene material, comprising the following steps:

[0021] (1) Mix the polyolefin thermoplastic elastomer with trimethylolpropane triacrylate TMPTA, St, and DCP in a container according to the mass ratio of (2000 - 2500):(60 - 80):(60 - 80):(10 - 20), and then add it to a twin-screw extruder for melt grafting reaction. The extruded spline is granulated after air cooling to obtain trimethylolpropane triacrylate TMPTA-grafted polyolefin thermoplastic elastomer;

[0022] (2) Using trimethylolpropane triacrylate TMPTA-grafted polyolefin thermoplastic elastomer as a compatibilizer, add polypropylene, inorganic filler, toughening agent, and nucleating agent in proportion, mix in a high-speed mixer to obtain a premix; add the premix to the main feeding port of a twin-screw extruder, carry out melt extrusion, granulate and dry to obtain the polypropylene material.

[0023] The present invention also provides an application of the polypropylene material in automotive water cutters and sealing strips.

[0024] Beneficial effects

[0025] (1) The present invention has the characteristics of good dimensional stability, high bonding strength with TPE materials, and high peel strength after high and low temperature cycling. This is because by adding a compatibilizer, appropriate proportions of inorganic filler, toughening agent, and nucleating agent, the coefficient of linear thermal expansion CLTE of the material is significantly lower than that of ordinary PP modified materials.

[0026] (2) Through a special compatibilizer, the present invention has good interfacial affinity between the PP resin and the inorganic filler, and can be well dispersed and compatible with the PP resin and the toughening agent at the same time, resulting in high product dimensional stability; in addition, the compatibilizer can reduce the melting point of the PP resin, significantly improve the peel strength between the PP resin and other materials, especially improve the compatibility between the PP resin and the thermoplastic elastomer, and increase the peel strength between the PP resin and the thermoplastic elastomer. Specific Embodiments

[0027] The following combines specific embodiments to further elaborate the present invention. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0028] Unless otherwise specified, the reagents, methods, and equipment used in the present invention are all conventional reagents, methods, and equipment in this technical field.

[0029] The raw materials used in the following examples and comparative examples are as follows:

[0030] PP1: PP B1101, homopolypropylene, with a melt flow rate of 0.5 g / 10 min at 230 °C and 2.16 kg, purchased from Formosa Plastics in Taiwan, China;

[0031] PP2: PP K8303, copolymer polypropylene, with a melt flow rate of 3.5 g / 10 min at 230 °C and 2.16 kg, purchased from Yanshan Petrochemical;

[0032] PP3: PP SP179 (Lanzhou Petrochemical), copolymer polypropylene, with a melt flow rate of 9 g / 10 min at 230 °C and 2.16 kg, purchased from Lanzhou Petrochemical

[0033] Inorganic filler 1: Talc powder 3000 mesh, purchased from Liaoning Tianyuan;

[0034] Inorganic filler 2: Talc powder 1250 mesh, purchased from Liaoning Tianyuan;

[0035] Inorganic filler 3: Calcium carbonate, commercially available;

[0036] Toughening agent 1: POE, POE ENGAGE 7467, purchased from Dow;

[0037] Toughening agent 2: POE, POE ENGAGE 8137, purchased from Dow;

[0038] Nucleating agent 1: HPN-20E, purchased from Milliken;

[0039] Nucleating agent 2: HPN-68L, purchased from Milliken;

[0040] Compatibilizer 1: Modified grafted polyolefin thermoplastic elastomer 1;

[0041] The preparation method includes: mixing ethylene-octene copolymer with trimethylolpropane triacrylate TMPTA and St in a container at a mass ratio of 2000:60:60, and then using DCP with a mass ratio of 10:2000 to the ethylene-octene copolymer as an initiator, adding it to a twin-screw extruder for melt grafting reaction. The extruded spline is air-cooled and pelletized to obtain a modified grafted ethylene-octene copolymer with a grafting rate of 10%. The temperatures of each section of the extruder are 170 °C, 170 °C, 180 °C, 180 °C, 180 °C, 200 °C, 200 °C. The screw speed is 70 r / min.

[0042] Compatibilizer 2: Modified grafted polyolefin thermoplastic elastomer 2;

[0043] The preparation method includes: mixing ethylene-butene copolymer with trimethylolpropane triacrylate (TMPTA) and St in a container according to a mass ratio of 2500:80:80 respectively, then using DCP with a mass ratio of 20:2500 to the ethylene-butene copolymer as an initiator, adding it to a twin-screw extruder for melt grafting reaction. The extruded sample bars are air-cooled and pelletized to obtain a modified grafted ethylene-butene copolymer with a grafting rate of 15%. The temperatures of each section of the extruder are 170°C, 170°C, 180°C, 180°C, 180°C, 200°C, 200°C. The screw speed is 70 r / min.

[0044] Compatibilizer 3: Modified grafted polyolefin thermoplastic elastomer 3;

[0045] The preparation method includes: mixing ethylene-butene copolymer with trimethylolpropane triacrylate (TMPTA) and St in a container according to a mass ratio of 2000:60:60 respectively, then using DCP with a mass ratio of 10:2000 to the ethylene-butene copolymer as an initiator, adding it to a twin-screw extruder for melt grafting reaction. The extruded sample bars are air-cooled and pelletized to obtain a modified grafted ethylene-butene copolymer with a grafting rate of 8%. The temperatures of each section of the extruder are 170°C, 170°C, 180°C, 180°C, 180°C, 180°C, 180°C. The screw speed is 60 r / min.

[0046] Compatibilizer 4: Modified grafted polyolefin thermoplastic elastomer 4;

[0047] The preparation method includes: mixing ethylene-butene copolymer with trimethylolpropane triacrylate (TMPTA) and St in a container according to a mass ratio of 2500:80:80 respectively, then using DCP with a mass ratio of 20:2500 to the ethylene-butene copolymer as an initiator, adding it to a twin-screw extruder for melt grafting reaction. The extruded sample bars are air-cooled and pelletized to obtain a modified grafted ethylene-butene copolymer with a grafting rate of 18%. The temperatures of each section of the extruder are 170°C, 170°C, 180°C, 180°C, 180°C, 220°C, 220°C. The screw speed is 80 r / min.

[0048] Compatibilizer 5: PP-g-MAH, CMG9801 Jia Yirong Compatibilizer Co., Ltd.

[0049] Compatibilizer 6: Polyolefin elastomer grafted with MAH (POE-g-MAH), CMG5805 Jia Yirong Compatibilizer Co., Ltd.

[0050] Compatibilizer 7: Polyolefin elastomer grafted with GMA (POE-g-GMA), SOG-03 Jiayirong Compatibilizer Jiangsu Co., Ltd.

[0051] The composite materials of each example and comparative example were prepared through the following process:

[0052] Add polypropylene, inorganic filler, toughener, nucleating agent and compatibilizers 1-7 in proportion, mix in a high-speed mixer for 1-3 min to obtain a premix; add the premix to the main feeding port of a twin-screw extruder, carry out melt extrusion, pelletize and dry to obtain the high-performance extruded coated skeleton polypropylene material.

[0053] The conditions of the melt extrusion step are as follows: the temperature of the first zone is 140-180 °C, the temperature of the second zone is 220-240 °C, the temperature of the third zone is 230-270 °C, the temperature of the fourth zone is 230-270 °C, the temperature of the fifth zone is 230-270 °C, the temperature of the sixth zone is 230-270 °C, the temperature of the seventh zone is 230-270 °C, the temperature of the eighth zone is 230-270 °C, the temperature of the ninth zone is 230-270 °C, and the main machine speed is 250-600 revolutions per minute; the length-diameter ratio of the twin-screw extruder is 40:1.

[0054] The examples and comparative examples were tested by the following test methods or standards:

[0055] The test of the coefficient of linear thermal expansion (CLTE) of the material was carried out with reference to ASTM D696. The temperature range was -30 °C - 80 °C, and the test direction was parallel to the flow direction.

[0056] Adhesive stripping strength: The test method was in accordance with VDI 2019. The specific process was as follows: First, the prepared PP material was made into a rectangular plate with a thickness of 2.0 mm and a size of 150*40 mm by injection molding or compression molding. Then, the rectangular plate was placed in an adhesive mold, and the thermoplastic elastomer material was adhesively bonded to the surface of the prepared PP material plate by injection molding at a temperature of 200 °C. A universal testing machine and a special fixture were used to peel the TPE soft rubber from the adhesive test plate. The force during the peeling process was measured and recorded.

[0057] Stripping strength after high and low temperatures: The test of the stripping strength after high and low temperature cycling was carried out with reference to the modern automotive standard MS210-05 and VDI 2019. The high temperature was 90 °C, the low temperature was -30 °C, and the time for one cycle was 24 h. The larger the value, the greater the adhesive stripping strength. When the adhesive stripping strength reached 3.0 N / mm, it indicated that the application requirements could be met.

[0058] Table 1 Raw material ratios and performance test results of examples and comparative examples

[0059]

[0060]

[0061] As can be seen from the above table, in Examples 1-16, a special compatibilizer was used, and the peel strength of the obtained polypropylene material was significantly improved, and at the same time, it had excellent high and low temperature resistance and a low linear expansion coefficient. Specifically, the linear expansion coefficient could reach 29-39 μm / (m·°C), the encapsulation peel strength could reach 4.1-5.5 N / mm, and the peel strength after high and low temperatures was 3.3-4.8 N / mm. Comparing Comparative Example 1 with Example 1, when the addition amount of PP resin was too much, the high and low temperature resistance of the material decreased. Comparative Examples 2 and 6 show that when the toughening agent or nucleating agent is not added to the material, only adding a special compatibilizer cannot solve the technical problems of the present invention. Comparative Examples 3 and 4 show that using a general compatibilizer cannot achieve the effect of the present invention, and Comparative Example 5 shows that using only POE-g-GMA, the compatibilization effect is not very good. Comparative Example 7 shows that when the addition amount of the compatibilizer is too small, the compatibility between PP and TPE is poor, and the CLTE and peel strength are relatively poor. Comparative Example 8 shows that when other inorganic fillers are used, the CLTE of the material is large and the peel strength after high and low temperatures is poor.

Claims

1. A polypropylene material, characterized in that: By weight parts, it includes the following components: 25 - 65 parts of polypropylene resin; 20 - 40 parts of inorganic filler; 10 - 20 parts of toughening agent; 5 - 15 parts of compatibilizer; 0.2 - 1 part of nucleating agent; Among them, the compatibilizer is trimethylolpropane triacrylate TMPTA grafted polyolefin thermoplastic elastomer; the preparation method of the trimethylolpropane triacrylate TMPTA grafted polyolefin thermoplastic elastomer includes the following steps: Mix polyolefin thermoplastic elastomer with trimethylolpropane triacrylate TMPTA, St, and DCP in a container according to the mass ratio of (2000 - 2500) : (60 - 80) : (60 - 80) : (10 - 20), then add it to a twin-screw extruder for melt grafting reaction. The extruded sample bars are cooled by air and pelletized to obtain trimethylolpropane triacrylate TMPTA grafted polyolefin thermoplastic elastomer; The polyolefin thermoplastic elastomer is at least one of ethylene-octene copolymer and ethylene-butene copolymer; The inorganic filler is talcum powder with a particle size of 1250 - 5000 mesh; The toughening agent is one or several of ethylene-octene copolymer, ethylene-propylene-diene monomer rubber, propylene-α-olefin copolymer, and SEBS; The nucleating agent is an organic salt nucleating agent.

2. The polypropylene material according to claim 1, wherein: The polypropylene resin is at least one of homopolypropylene and copolymer polypropylene, and its melt flow rate under the conditions of 230°C and 2.16 kg is 0.5 - 9 g / 10min.

3. The polypropylene material according to claim 1, wherein: 35 - 45 parts of the polypropylene resin; 25 - 30 parts of inorganic filler; 8 - 10 parts of compatibilizer.

4. A preparation method of a polypropylene material as described in any one of claims 1 - 3, including the following steps: (1) Mix polyolefin thermoplastic elastomer with trimethylolpropane triacrylate TMPTA, St, and DCP in a container according to the mass ratio of (2000 - 2500) : (60 - 80) : (60 - 80) : (10 - 20), then add it to an extruder for melt grafting reaction. The extruded sample bars are cooled by air and pelletized to obtain trimethylolpropane triacrylate TMPTA grafted polyolefin thermoplastic elastomer; (2) Using trimethylolpropane triacrylate TMPTA grafted polyolefin thermoplastic elastomer as a compatibilizer, add polypropylene, inorganic filler, toughening agent, and nucleating agent in proportion, mix to obtain a premix; add the premix to the main feeding port of the extruder, carry out melt extrusion, pelletize and dry to obtain the polypropylene material.

5. An application of a polypropylene material as described in any one of claims 1 - 3 in a sealing strip.

6. The application according to claim 5, wherein: The sealing strip includes an automotive water cut.

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