A low-haze scratch-resistant polypropylene composite material and a preparation method and application thereof

Abstract

This invention provides a low-haze, scratch-resistant polypropylene composite material. The low-haze, scratch-resistant polypropylene composite material comprises, by weight, the following components: 100 parts polypropylene, 0-55 parts filler, 5-30 parts acrylamide, 10-55 parts POSS, 0.01-0.1 parts amide-based scratch-resistant agent, and 0-1 parts other additives. By adding acrylamide and POSS to the polypropylene composite material, the thermal scratch resistance of the material at both room temperature and high temperature is synergistically improved, while the influence of the amide-based scratch-resistant agent on the haze of the polypropylene material is reduced. This results in a polypropylene composite material that possesses both excellent room-temperature and high-temperature aging scratch resistance and low haze.

Description

Technical Field

[0001] This invention relates to the field of engineering plastics technology, and more specifically, to a low-haze, scratch-resistant polypropylene composite material, its preparation method, and its application. Background Technology

[0002] Polypropylene, with its low density, high cost-effectiveness, excellent heat resistance, rigidity, chemical resistance, ease of processing and recycling, is widely used in automobiles, becoming the most widely used and fastest-growing plastic in the automotive industry. In recent years, the rapid development of the automotive industry has placed increasingly higher demands on interior and exterior trim materials, such as dashboards, door panels, and bumpers, requiring high strength, impact resistance, scratch resistance, and good dimensional stability.

[0003] Polypropylene (PP) is easily scratched by external forces, which significantly affects the appearance of finished products and limits its widespread application in automotive interior materials. Currently, scratch-resistant agents are mainly added to improve the scratch resistance of PP. However, these agents are primarily amide-based and silicone-based. Amide-based agents affect the light transmittance of PP, especially increasing haze and impacting appearance. Furthermore, amide-based agents degrade and precipitate under photothermal conditions, further reducing scratch resistance and failing to meet the requirements for high-temperature outdoor applications in automotive interiors during summer. While silicone-based scratch-resistant agents have less impact on the light transmittance of PP, their larger molecular weight limits their mobility in the matrix compared to amide-based agents, resulting in poorer scratch resistance. Additionally, silicone-based agents require larger quantities, increasing manufacturing costs.

[0004] Chinese patent CN117126493A discloses a highly scratch-resistant and transparent polypropylene material. This invention employs a specially designed hardening and light-reflecting agent, which is a copolymer of POSS (methacryloyloxypropyl cage-type polysilsesquioxane), norbornene, glycidyl methacrylate, and / or maleic anhydride. It also uses a composite of highly transparent random copolymer polypropylene and homopolymer polypropylene with high surface hardness, matched with a highly transparent elastic material. A light-diffusing agent is used to achieve uniform light distribution and transmission, while a nucleating agent reduces crystal size, thus improving the material's light transmittance and scratch resistance. However, the hardening and light-reflecting agent and scratch-resistant agent have limited effect on improving the scratch resistance of the polypropylene composite surface, and excessive use of the scratch-resistant agent can affect the material's light transmittance.

[0005] Therefore, how to provide a polypropylene composite material that combines excellent scratch resistance at both room and high temperatures with low haze remains a technical problem that urgently needs to be solved. Summary of the Invention

[0006] The primary objective of this invention is to overcome the aforementioned problems in the prior art and to provide a low-haze, scratch-resistant polypropylene composite material.

[0007] A second objective of this invention is to provide a method for preparing a low-haze, scratch-resistant polypropylene composite material.

[0008] A third objective of this invention is to provide the application of the aforementioned low-haze, scratch-resistant polypropylene composite material in the manufacture of automotive parts.

[0009] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0010] A low-haze, scratch-resistant polypropylene composite material, comprising the following components by weight:

[0011] 100 parts polypropylene, 0-55 parts filler, 5-30 parts acrylamide, 10-55 parts POSS, 0.01-0.1 parts amide-based scratch-resistant agent, and 0-1 parts other additives.

[0012] The propylene groups in the acrylamide added in this invention ensure its compatibility and diffusion ability within the polypropylene matrix. The combined action of acrylamide and POSS further enhances the migration speed of amide-based scratch-resistant agents within the polypropylene matrix, allowing more scratch-resistant agents to rapidly migrate to the polypropylene material surface during crystallization, forming a scratch-resistant film and significantly improving the scratch resistance of the polypropylene composite material at both room and high temperatures. Simultaneously, the polarity of the amide bonds in acrylamide and their adsorption effect on the silicon-oxygen bonds in POSS enable the POSS to form stable, small-particle-size aggregates within the polypropylene matrix. This ensures a uniform distribution of the polypropylene crystalline phase and forms a network structure, preventing the precipitation of small molecules from the amide-based scratch-resistant agents onto the material surface, thus reducing haze and further improving the material's light transmittance. Furthermore, the POSS's cage-like network structure provides support within the system, enhancing the tensile strength of the polypropylene composite material.

[0013] Preferably, the melt flow rate of the polypropylene at 230°C and 2.16 kg is 1–60 g / 10 min.

[0014] In this invention, the melt flow rate of the polypropylene can be 1 g / 10 min, 5 g / 10 min, 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, 50 g / 10 min, 55 g / 10 min, 60 g / 10 min, or any value within the range.

[0015] More preferably, the melt flow rate of the polypropylene at 230°C and 2.16 kg is 10–35 g / 10 min. That is, the melt flow rate of the polypropylene can be 10 g / 10 min, 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, 30 g / 10 min, 32 g / 10 min, 35 g / 10 min, etc., or any range formed by the above values, such as 10–20 g / 10 min, 25–35 g / 10 min, etc., but is not limited thereto.

[0016] When the melt flow rate of the polypropylene is within this range, the polypropylene composite system exhibits good fluidity, which is beneficial for the uniform mixing of the various raw material components. This allows for the preparation of polypropylene with both high light transmittance and scratch resistance. The melt flow rate (MFR) of the polypropylene was measured according to the standard method of ISO 1133-1:2011.

[0017] Preferably, in the low-haze scratch-resistant polypropylene composite material, the mass content of polypropylene is not less than 42%.

[0018] Preferably, the polypropylene includes at least one of block copolymer polypropylene, homopolymer polypropylene, and random copolymer polypropylene.

[0019] More preferably, the polypropylene is block copolymer polypropylene.

[0020] Preferably, the filler includes at least one of talc, calcium carbonate, and basic magnesium sulfate whiskers.

[0021] Preferably, the POSS comprises at least one of octaaminopropyl cage-type polysilsesquioxane and its derivatives, octacyclooxypropyl cage-type polysilsesquioxane and its derivatives, octacarboxyethylenide cage-type polysilsesquioxane and its derivatives, and octamethacryloxypropyl cage-type polysilsesquioxane and its derivatives.

[0022] Preferably, the amide-based scratch-resistant agent includes at least one of erucamide and oleamide.

[0023] Preferably, the other additives are antioxidants.

[0024] Preferably, the antioxidant is a hindered phenolic antioxidant and / or a phosphite antioxidant.

[0025] The preferred amount of hindered phenolic antioxidant is 0.1 to 0.3 parts.

[0026] The preferred amount of the phosphite antioxidant is 0.1 to 0.3 parts. More preferably, the hindered phenolic antioxidant is antioxidant 1010; and the phosphite antioxidant is antioxidant 168.

[0027] The preparation method of the above-mentioned low-haze scratch-resistant polypropylene composite material includes the following steps:

[0028] According to the above-mentioned weight proportions, polypropylene, filler, acrylamide, POSS, amide-based scratch-resistant agent, and antioxidant are mixed evenly and then melt-extruded to prepare the low-haze scratch-resistant polypropylene composite material.

[0029] Preferably, the temperature of the melt extrusion is 170–210°C.

[0030] Preferably, the melt extrusion is performed using a twin-screw extruder, wherein the temperature range from the feeding section to the die head in the twin-screw extruder is 170±5℃, 200±5℃, 200±5℃, 210±5℃, 210±5℃, 205±5℃, 205±5℃, 200±5℃, 200±5℃.

[0031] The application of the aforementioned low-haze, scratch-resistant polypropylene composite material in the manufacture of automotive parts.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] This invention overcomes the effects of amide-based scratch-resistant agents on the haze of polypropylene materials and the impact of their easy decomposition at high temperatures on the scratch resistance of the material by adding acrylamide and POSS to a polypropylene system using amide-based scratch-resistant agents. The resulting polypropylene composite material has both excellent scratch resistance at room temperature and high temperature and low haze. Surprisingly, its tensile properties are also further improved.

[0034] Furthermore, the polypropylene composite material preparation formula and process of the present invention are simple, which can reduce production costs and has practical application value. Detailed Implementation

[0035] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0036] The embodiments of the present invention use the following raw materials:

[0037] Polypropylene:

[0038] Polypropylene 1: BX3500 (block copolymer polypropylene, MFR = 10g / 10min at 230℃ and 2.16kg load), purchased from SKIC Korea;

[0039] Polypropylene 2: BX3800 (block copolymer polypropylene, MFR = 30 g / 10 min at 230℃ and 2.16 kg load), purchased from SKIC Korea;

[0040] Polypropylene 3: SZ30S (homopolymer polypropylene, MFR=30g / 10min at 230℃ and 2.16kg load), purchased from Sinopec-Korea Petrochemical (Wuhan);

[0041] Polypropylene 4: SM198 (random copolymer polypropylene), MFR = 2.5g / 10min at 230℃ and 2.16kg load, purchased from Tateng, Malaysia;

[0042] Polypropylene 5: BX3900 (random copolymer polypropylene, MFR=60g / 10min at 230℃ and 2.16kg load), purchased from SKIC Korea;

[0043] filler:

[0044] Calcium carbonate: 75T, purchased from Changxing Oumia;

[0045] Whiskers: WS-1S2 (basic magnesium sulfate whiskers), purchased from Yingkou Kangru Technology;

[0046] Talc powder: TYT-777A (3000 mesh talc powder), purchased from Liaoning Tianyuan;

[0047] Scratch-resistant agent:

[0048] Erucamide: purchased from Shanghai Kaiyin Chemical Co., Ltd.

[0049] Oleamide: purchased from Shanghai Kaiyin Chemical Co., Ltd.

[0050] Silicone masterbatch: MB25-502, purchased from Dow Corning, USA;

[0051] Acrylamide: Commercially available;

[0052] POSS:

[0053] Octamethacryloyloxypropyl cage-type polysilsesquioxane (MMA-□POSS): Purchased from HybridPlastics, USA;

[0054] Octaaminopropyl cage-type polysilsesquioxane: purchased from HybridPlastics, USA;

[0055] Antioxidants:

[0056] Antioxidant 1010: Commercially available;

[0057] Antioxidant 168: Commercially available.

[0058] Unless otherwise specified, all components used in the parallel embodiments and comparative examples are the same commercially available products.

[0059] Example 1

[0060] A low-haze, scratch-resistant polypropylene composite material, the weight parts of the raw materials used are shown in Table 1.

[0061] The preparation method of the above-mentioned low-haze scratch-resistant polypropylene composite material includes the following steps:

[0062] According to the weight proportions in Table 1, polypropylene, filler, acrylamide, POSS, amide-based scratch-resistant agent, and antioxidant were mixed evenly and then melt-extruded to prepare the low-haze scratch-resistant polypropylene composite material. The melt extrusion was performed using a twin-screw extruder, with the following temperatures from the feed section to the die head: 170℃, 200℃, 200℃, 210℃, 210℃, 205℃, 205℃, 205℃, 200℃, 200℃.

[0063] Examples 2 to 14 and Comparative Examples 1 to 4

[0064] The weight proportions of raw materials used in Examples 2 to 14 and Comparative Examples 1 to 4 are shown in Table 1. The preparation steps of Examples 2 to 14 and Comparative Examples 1 to 4 are the same as those in Example 1.

[0065] Table 1 Formulation components of Examples 1 to 14

[0066]

[0067]

[0068] Continued from Table 1

[0069]

[0070] Table 2 Formulation components of Comparative Examples 1 to 4

[0071]

[0072] Performance testing

[0073] The properties of the polypropylene composite materials obtained in the above embodiments and comparative examples were characterized. The specific test items, test methods, and results are as follows:

[0074] (1) The scratch resistance test was conducted according to PV3952, with a load of 10N. The scratch resistance performance was judged by measuring the ΔL value (i.e. the change of black and white color) on the surface of the scratched sample. The smaller the value of ΔL, the better the scratch resistance performance of the material. The scratch resistance test results after room temperature (25℃) and heat aging (102℃, 168h) are shown in Table 2.

[0075] The scratch resistance after heat aging is characterized by the ΔL retention rate, calculated as follows: ΔL retention rate (%) = (ΔL / ΔL) / ΔL ... t -ΔL0) / ΔL0×100%, ΔL t The result represents the scratch resistance test after thermal aging, while ΔL0 represents the scratch resistance test result at room temperature.

[0076] (2) Tensile strength was tested according to standard ISO 527-2:2012. The sample size was 170mm×10mm×4mm, the tensile rate was 50mm / min, and the test results are shown in Table 2.

[0077] (3) Haze test: The haze of the polypropylene composition was tested using a 2mm thick disc with a diameter of 80mm according to the TSM0503G ordinary B method. The lower the transmittance F (%) of all glass discs, the higher the haze of the material and the more volatile small molecules it contains. The test temperature was 100℃. The test results are shown in Table 2.

[0078] Table 3 Performance test results of Examples 1-15 and Comparative Examples 1-4

[0079]

[0080]

[0081] Data from Examples 1-15 show that by adding acrylamide and POSS to a polypropylene system using amides as scratch-resistant agents, the effects of amides on the haze of polypropylene materials and the effects of the easy decomposition of amides at high temperatures on the scratch resistance of the material were overcome. The resulting polypropylene composite material exhibits both excellent scratch resistance at room temperature and high temperature and low haze. Surprisingly, the tensile properties were further improved. The transmittance F-value of the polypropylene composite material under the TSM0503G ordinary B method test conditions is above 80%, reaching as high as 88%; the scratch resistance can reach ΔL < 0.4, and the ΔL retention rate after heat aging is above 80%.

[0082] The results of Examples 1 and 6 show that reducing the amount of added filler will reduce the tensile strength of the polypropylene composite material. At the same time, due to the increased content of scratch-resistant agent in the polypropylene composite material, the scratch resistance and haze of the material are improved.

[0083] The results of Examples 1 and 7-8 show that, within the dosage range provided by this invention, the scratch resistance and mechanical strength initially increase and then decrease with increasing acrylamide dosage. The addition of acrylamide can work synergistically with POSS to improve the light transmittance of the composite material; however, since acrylamide is a polar compound and polypropylene is a non-polar polymer, further increasing the acrylamide content beyond a certain point in the polypropylene matrix may lead to phase separation. The polar acrylamide adsorbs more POSS, resulting in agglomerated particles in the polypropylene matrix, which in turn worsens the dispersibility of the components, leading to a decrease in scratch resistance and mechanical strength.

[0084] Examples 1 and 9-10 show that when the content of POSS increases to a certain amount, further increases will cause agglomeration in the matrix, leading to a decrease in mechanical properties. Within the dosage range of the present invention, the impact on scratch resistance is relatively small.

[0085] The results of Comparative Examples 1-3 show that acrylamide and POSS have a synergistic effect, which can improve the scratch resistance, tensile strength and light transmittance F-value of polypropylene composites.

[0086] The results of Comparative Example 4 show that replacing the amide-based scratch-resistant agent with a non-amide-based scratch-resistant agent results in a decrease in the room temperature and high temperature aging scratch resistance of the prepared polypropylene composite material.

[0087] Obviously, 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 can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments 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 low haze, scratch resistant polypropylene composite, characterized in that, By weight, it includes the following components: 100 parts polypropylene, 0-55 parts filler, 5-30 parts acrylamide, 10-55 parts POSS, 0.01-0.1 parts amide-based scratch-resistant agent, and 0-1 parts other additives; The POSS includes at least one of the following: octaaminopropyl cage polysilsesquioxane and its derivatives, octacyclooxypropyl cage polysilsesquioxane and its derivatives, octacarboxyethyl cage polysilsesquioxane and its derivatives, and octamethacryloxypropyl cage polysilsesquioxane and its derivatives. The preparation method of the low-haze scratch-resistant polypropylene composite material includes the following steps: After the raw material components are mixed evenly, they are melt-extruded to prepare the low-haze scratch-resistant polypropylene composite material.

2. The low haze, scratch resistant polypropylene composite of claim 1, wherein, The polypropylene has a melt flow rate of 1–60 g / 10 min at 230 °C and 2.16 kg.

3. The low haze, scratch resistant polypropylene composite of claim 1, wherein, The polypropylene includes at least one of block copolymer polypropylene, homopolymer polypropylene, and random copolymer polypropylene.

4. The low haze, scratch resistant polypropylene composite of claim 1, wherein, The polypropylene has a melt flow rate of 10–35 g / 10 min at 230 °C and 2.16 kg.

5. The low haze, scratch resistant polypropylene composite of claim 1, wherein, The filler includes at least one of talc, calcium carbonate, and basic magnesium sulfate whiskers.

6. The low haze, scratch resistant polypropylene composite of claim 1, wherein, The amide-based scratch-resistant agent includes at least one of erucamide and oleamide.

7. The low-haze, scratch-resistant polypropylene composite material according to claim 1, characterized in that, The other additives are antioxidants.

8. The use of the low-haze scratch-resistant polypropylene composite material according to any one of claims 1 to 7 in the preparation of automotive parts.

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