High-surface-hardness polypropylene composite material and preparation method thereof

Abstract

The invention provides a polypropylene composite material with high surface hardness. The composite material is prepared from the following components in parts by weight: 60 to 100 parts of polypropylene resin, 6 to 12 parts of polymethyl methacrylate, 4 to 10 parts of polyhedral oligomeric silsesquioxane, 3 to 6 parts of organic silicon modified polyurethane, 1 to 3 parts of rare earth oxide, 5 to 10 parts of hollow glass beads, 0.5 to 1.5 parts of a coupling agent, 0.2 to 0.4 part of aluminum hydroxide and 0.4 to 0.8 part of an antioxidant. The preparation process is simple, not complex and easy to popularize, and the obtained polypropylene composite material overcomes the problem of low surface hardness in the prior art and has high surface hardness and excellent mechanical properties.

Description

Technical Field

[0001] The invention belongs to the field of polypropylene material preparation, and specifically relates to a polypropylene composite material with high surface hardness and a preparation method thereof. Background Art

[0002] Polypropylene is a thermoplastic made from the polymerization of propylene monomers. It has chemical resistance, heat resistance, electrical insulation, high-strength mechanical properties and good high-wear processing properties, and is widely used in many fields such as machinery, automobiles, electronic appliances, construction, textiles, packaging, agriculture, forestry, fisheries and food industries. However, polypropylene has the problem of low surface hardness.

[0003] Patent CN 104479218 A provides a low-gloss high-hardness polypropylene composite material and a preparation method thereof, which improves the hardness of the polypropylene composite material by adding PVC resin, nucleating agent and metal powder to the components, but the addition of PVC resin limits the application field of the material; Patent CN 106589552 A provides a preparation method of high-hardness plastic, which greatly improves the hardness of the plastic by adding metal, graphite, titanium dioxide and glass fiber, but this method greatly reduces the impact performance of the material, and it is difficult to balance the rigidity and toughness by adjusting the formula; Patent CN 111073158 A provides a high-hardness polypropylene heat shrink sleeve substrate and a preparation method thereof, which mainly prepares the product by adding a crosslinking agent and a nucleating agent to the components and then crosslinking by radiation. Although the surface hardness of the obtained product is improved, the product preparation process is complicated and not easy to promote. Summary of the invention

[0004] The present invention aims to provide a polypropylene composite material with high surface hardness and a preparation method thereof. By adding components such as polymethyl methacrylate, cage polysilsesquioxane, silicone-modified polyurethane, rare earth oxides, hollow glass microbeads and the like into polypropylene, the surface hardness of the polypropylene composite material is significantly improved without affecting other mechanical properties.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A high surface hardness polypropylene composite material comprises the following components in parts by weight: 60-100 parts of polypropylene resin, 6-12 parts of polymethyl methacrylate, 4-10 parts of cage-type polysilsesquioxane, 3-6 parts of organosilicon-modified polyurethane, 1-3 parts of rare earth oxide, 5-10 parts of hollow glass microspheres, 0.5-1.5 parts of coupling agent, 0.2-0.4 parts of aluminum hydroxide and 0.4-0.8 parts of antioxidant.

[0007] Preferably, the polypropylene resin has a melt index of 20-30 g / 10 min at 2.16 kg and 230° C.

[0008] Preferably, the polymethyl methacrylate has a molecular weight of 50,000-70,000 g / mol and a melt index of 18-22 g / 10 min.

[0009] Preferably, the number average molecular weight of the organosilicon-modified polyurethane is 40,000-80,000, and the proportion of organosiloxane is 40-50%.

[0010] Preferably, the rare earth oxide has a particle size of 20-40 nm and is one or a mixture of cerium oxide and lanthanum oxide.

[0011] Preferably, the hollow glass microspheres have a D50 of 8-12 μm and a tap density of 0.5-0.8 g / cc.

[0012] Preferably, the coupling agent is a silane coupling agent or a titanate coupling agent.

[0013] Preferably, the antioxidant is a composite antioxidant composed of a hindered phenol antioxidant and a phosphite antioxidant in a mass ratio of 1:1.3-1.5.

[0014] The method for preparing the above-mentioned high surface hardness polypropylene composite material comprises the following steps:

[0015] S1: Add 3-6 parts of organosilicon-modified polyurethane into a reaction kettle, raise the temperature to 70-80°C, add 0.5-1.5 parts of rare earth oxide while stirring, and continue stirring for 15-25 minutes after the addition is completed to obtain component A;

[0016] S2: Mix 6-12 parts of polymethyl methacrylate and 4-10 parts of cage-type polysilsesquioxane, raise the temperature to 130-140° C., add 5-10 parts of hollow glass microspheres while stirring, and continue stirring for 20-30 minutes after the addition is completed to obtain component B;

[0017] S3: 60-100 parts of polypropylene resin, component A obtained in step S1, component B obtained in step S2, 0.5-1.5 parts of coupling agent, 0.2-0.4 parts of aluminum hydroxide and 0.4-0.8 parts of antioxidant are mixed for 10-15 minutes, and then put into a twin-screw extruder for melt extrusion, cooling, pelletizing and packaging to obtain the high surface hardness polypropylene composite material.

[0018] Preferably, the process parameters of melt extrusion in step S3 are: the extruder screw speed is 400-500rpm, the feeding rate is 15-20Hz; the temperature of the extruder is: zone 1 temperature 190°C, zone 2 temperature 200°C, zone 3 temperature 215°C, zone 4 temperature 220°C, zone 5 temperature 230°C, zone 6 temperature 230°C, and head temperature 220°C.

[0019] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0020] 1. The present invention uses silicone-modified polyurethane to coat rare earth oxides, utilizes the larger atomic radius of rare earth elements to affect external lattice distortion, and improves surface hardness by increasing the difficulty of slip; at the same time, the silicone-modified polyurethane contains silicone structural units in a long-chain branched structure, and the silicone structure is easier to be outside the surface, synergistically increasing the scratch resistance and improving the hardness.

[0021] 2. In the present invention, polymethyl methacrylate and cage-type polysilsesquioxane include hollow glass microspheres, which migrate to the surface of the material during the molding process of the polypropylene composite material through the melting temperature difference between the polypropylene resin and the polypropylene resin, forming a protective layer film containing hollow glass microspheres, thereby further improving the wear resistance and surface hardness.

[0022] 3. The present invention optimizes the specific polypropylene resin, component A, component B and other components, and the components work synergistically and interweave with each other to form a spatial structure, so that the stability and mechanical properties are better. DETAILED DESCRIPTION

[0023] 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.

[0024] The raw materials used in the present invention are as follows:

[0025] Polypropylene resin was purchased from Wuhan Haishan Technology Co., Ltd. with item number 1638; polymethyl methacrylate was purchased from Shanghai Yuanye Biotechnology Co., Ltd. with item number S30622; cage polysilsesquioxane was purchased from Xi'an Ruixi Biotechnology Co., Ltd. with item number 1014; silicone-modified polyurethane was purchased from Shandong Haoming Chemical Technology Co., Ltd. with item number 0007; hollow glass microspheres were purchased from Hebei Wensheng New Materials Technology Co., Ltd. with item number 50; coupling agent was purchased from Jinan Yongyue Chemical Co., Ltd. with item number yy-3; 2,6-di-tert-butyl-4-methylphenol was purchased from Shanghai Yuanye Biotechnology Co., Ltd. with item number S30257; dioctadecyl phosphite was purchased from Hubei Henglvyuan Technology Co., Ltd. with item number 5121.

[0026] Example 1

[0027] This embodiment provides a method for preparing a polypropylene composite material with high surface hardness, comprising the following steps:

[0028] S1: Selecting a silicone-modified polyurethane with a number average molecular weight of 40,000 and a proportion of 40% of organosiloxane; cerium oxide with a particle size of 20 nm;

[0029] 3 g of organosilicon-modified polyurethane was added into the reaction kettle, the temperature was raised to 70°C, 0.5 g of cerium oxide was added while stirring at a rate of 600 r / min, and after the addition was completed, stirring was continued at a rate of 600 r / min for 15 min to obtain component A;

[0030] S2: Select polymethyl methacrylate with a molecular weight of 50000 g / mol and a melt index of 18 g / 10 min; hollow glass microspheres with a D50 of 8 μm and a tap density of 0.5 g / cc;

[0031] 6 g of polymethyl methacrylate and 4 g of cage-type polysilsesquioxane were mixed, the temperature was raised to 130° C., 5 g of hollow glass microspheres were added while stirring at a rate of 500 r / min, and after the addition was completed, the stirring was continued at a rate of 500 r / min for 20 min to obtain component B;

[0032] S3: Select a polypropylene resin with a melt index of 20 g / 10 min under the conditions of 2.16 kg and 230° C.; mix 60 g of the polypropylene resin, component A obtained in step S1, component B obtained in step S2, 0.5 g of coupling agent γ-aminopropyltriethoxysilane, 0.2 g of aluminum hydroxide and 0.4 g of an antioxidant (a composition of 2,6-di-tert-butyl-4-methylphenol and dioctadecyl phosphite in a mass ratio of 1:1.3) for 10 min, and then put it into a twin-screw extruder for melt extrusion, the screw speed of the extruder is 400 rpm, and the feeding rate is 15 Hz; the temperature of the extruder is: zone 1 temperature 190° C., zone 2 temperature 200° C., zone 3 temperature 215° C., zone 4 temperature 220° C., zone 5 temperature 230° C., zone 6 temperature 230° C., and die head temperature 220° C.; then cool, pelletize and package to obtain the high surface hardness polypropylene composite material.

[0033] Example 2

[0034] This embodiment provides a method for preparing a polypropylene composite material with high surface hardness, comprising the following steps:

[0035] S1: Selecting a silicone-modified polyurethane with a number average molecular weight of 80,000 and a proportion of 50% of organosiloxane; lanthanum oxide with a particle size of 40 nm;

[0036] 6 g of organosilicon-modified polyurethane was added into the reaction kettle, the temperature was raised to 80°C, 1.5 g of lanthanum oxide was added while stirring at a rate of 500 r / min, and after the addition was completed, the mixture was stirred at a rate of 600 r / min for 25 min to obtain component A;

[0037] S2: Select polymethyl methacrylate with a molecular weight of 70000 g / mol and a melt index of 22 g / 10 min; hollow glass microspheres with a D50 of 12 μm and a tap density of 0.8 g / cc;

[0038] 12g of polymethyl methacrylate and 10g of cage-type polysilsesquioxane were mixed, the temperature was raised to 140°C, 10g of hollow glass microspheres were added while stirring at a rate of 500r / min, and stirring was continued for 30min after the addition was completed to obtain component B;

[0039] S3: Select a polypropylene resin with a melt index of 30 g / 10 min under the conditions of 2.16 kg and 230° C.; mix 100 g of the polypropylene resin, component A obtained in step S1, component B obtained in step S2, 1.5 g of coupling agent γ-aminopropyltriethoxysilane, 0.4 g of aluminum hydroxide and 0.8 g of an antioxidant (a composition of 2,6-di-tert-butyl-4-methylphenol and dioctadecyl phosphite in a mass ratio of 1:1.5) for 15 min, and then put it into a twin-screw extruder for melt extrusion, the extruder screw speed is 500 rpm, and the feeding rate is 20 Hz; the temperature of the extruder is: zone 1 temperature 190° C., zone 2 temperature 200° C., zone 3 temperature 215° C., zone 4 temperature 220° C., zone 5 temperature 230° C., zone 6 temperature 230° C., and die head temperature 220° C.; then cool, pelletize and package to obtain the high surface hardness polypropylene composite material.

[0040] Example 3

[0041] This embodiment provides a method for preparing a polypropylene composite material with high surface hardness, comprising the following steps:

[0042] S1: Selecting a silicone-modified polyurethane with a number average molecular weight of 65,000 and a proportion of 45% of organosiloxane; cerium oxide and lanthanum oxide with a particle size of 20-40 nm;

[0043] 5 g of organosilicon-modified polyurethane was added to the reaction kettle, the temperature was raised to 75°C, 0.6 g of cerium oxide and 0.4 g of lanthanum oxide were added while stirring at a rate of 600 r / min, and after the addition was completed, stirring was continued at a rate of 600 r / min for 20 min to obtain component A;

[0044] S2: Select polymethyl methacrylate with a molecular weight of 60000 g / mol and a melt index of 20 g / 10 min; hollow glass microspheres with a D50 of 10 μm and a tap density of 0.7 g / cc;

[0045] 10 g of polymethyl methacrylate and 7 g of cage-type polysilsesquioxane were mixed, the temperature was raised to 135° C., 7 g of hollow glass microspheres were added while stirring at a rate of 500 r / min, and stirring was continued for 25 min after the addition was completed to obtain component B;

[0046] S3: Select a polypropylene resin with a melt index of 25g / 10min under the conditions of 2.16kg and 230°C; mix 80g of the polypropylene resin, component A obtained in step S1, component B obtained in step S2, 1g of coupling agent γ-aminopropyltriethoxysilane, 0.3g of aluminum hydroxide and 0.6g of an antioxidant (a composition of 2,6-di-tert-butyl-4-methylphenol and dioctadecyl phosphite in a mass ratio of 1:1.4) for 12min, and then put it into a twin-screw extruder for melt extrusion, the screw speed of the extruder is 450rpm, and the feeding rate is 18Hz; the temperature of the extruder is: zone 1 temperature 190°C, zone 2 temperature 200°C, zone 3 temperature 215°C, zone 4 temperature 220°C, zone 5 temperature 230°C, zone 6 temperature 230°C, and head temperature 220°C; then cool, pelletize and package to obtain the high surface hardness polypropylene composite material.

[0047] Comparative Example 1

[0048] The difference from Example 1 is that step S1 is omitted, that is, component A is not added in step S3, and the other steps remain unchanged.

[0049] Comparative Example 2

[0050] The difference from Example 1 is that step S1 lacks cerium oxide, and the other steps remain unchanged.

[0051] Comparative Example 3

[0052] The difference from Example 1 is that step S2 is missing, that is, component B is not added in step S3, and the other steps remain unchanged.

[0053] Comparative Example 4

[0054] The difference from Example 1 is that polymethyl methacrylate is missing in step S2, and the other steps remain unchanged.

[0055] Comparative Example 5

[0056] The difference from Example 1 is that the cage-type polysilsesquioxane is missing in step S2, and the other steps remain unchanged.

[0057] Comparative Example 6

[0058] The difference from Example 1 is that hollow glass microspheres are missing in step S2, and the other steps remain unchanged.

[0059] Performance Test:

[0060] The surface hardness was tested according to the pencil test method for coating hardness of GB / T 6739-1996; the tensile strength was tested according to GB / T1447-2005; the bending strength was tested according to GB / T 9341-2000; and the notched impact strength was tested according to GB / T1843-2008. The results are shown in the following table.

[0061] Table 1

[0062]

[0063]

[0064] It can be seen from the above performance test results that the products prepared in Examples 1-3 have excellent surface hardness, tensile strength and toughness. In particular, the comprehensive performance of Example 3 is the most outstanding. However, since Comparative Examples 1-6 do not adopt the necessary technical solutions, their corresponding performance tests are significantly worse than those of the Examples. The above experimental results further prove the importance of the technical solutions defined in the present invention for its technical effects.

[0065] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high surface hardness polypropylene composite material, characterized in that: The invention comprises the following components in parts by weight: 60-100 parts of polypropylene resin, 6-12 parts of polymethyl methacrylate, 4-10 parts of cage-type polysilsesquioxane, 3-6 parts of organosilicon-modified polyurethane, 1-3 parts of rare earth oxide, 5-10 parts of hollow glass microspheres, 0.5-1.5 parts of coupling agent, 0.2-0.4 parts of aluminum hydroxide and 0.4-0.8 parts of antioxidant.

2. The high surface hardness polypropylene composite material according to claim 1, characterized in that: The polypropylene resin has a melt index of 20-30 g / 10 min at 2.16 kg and 230° C.

3. The high surface hardness polypropylene composite material according to claim 1, characterized in that: The polymethyl methacrylate has a molecular weight of 50,000-70,000 g / mol and a melt index of 18-22 g / 10 min.

4. The high surface hardness polypropylene composite material according to claim 1, characterized in that: The number average molecular weight of the organosilicon-modified polyurethane is 40,000-80,000, and the proportion of organosiloxane is 40-50%.

5. The high surface hardness polypropylene composite material according to claim 1, characterized in that: The rare earth oxide has a particle size of 20-40 nm and is one or a mixture of cerium oxide and lanthanum oxide.

6. The high surface hardness polypropylene composite material according to claim 1, characterized in that: The hollow glass microspheres have a D50 of 8-12 μm and a tap density of 0.5-0.8 g / cc.

7. The high surface hardness polypropylene composite material according to claim 1, characterized in that: The coupling agent is a silane coupling agent or a titanate coupling agent.

8. The high surface hardness polypropylene composite material according to claim 1, characterized in that: The antioxidant is a composite antioxidant composed of a hindered phenol antioxidant and a phosphite antioxidant in a mass ratio of 1:1.3-1.

5.

9. A method for preparing a polypropylene composite material with high surface hardness, characterized in that: The steps include: S1: Add 3-6 parts of organosilicon-modified polyurethane into a reaction kettle, raise the temperature to 70-80°C, add 0.5-1.5 parts of rare earth oxide while stirring, and continue stirring for 15-25 minutes after the addition is completed to obtain component A; S2: Mix 6-12 parts of polymethyl methacrylate and 4-10 parts of cage-type polysilsesquioxane, raise the temperature to 130-140° C., add 5-10 parts of hollow glass microspheres while stirring, and continue stirring for 20-30 minutes after the addition is completed to obtain component B; S3: 60-100 parts of polypropylene resin, component A obtained in step S1, component B obtained in step S2, 0.5-1.5 parts of coupling agent, 0.2-0.4 parts of aluminum hydroxide and 0.4-0.8 parts of antioxidant are mixed for 10-15 minutes, and then put into a twin-screw extruder for melt extrusion, cooling, pelletizing and packaging to obtain the high surface hardness polypropylene composite material.

10. The method for preparing a polypropylene composite material with high surface hardness according to claim 9, characterized in that: The process parameters of melt extrusion in step S3 are: the extruder screw speed is 400-500rpm, the feeding rate is 15-20Hz; the temperature of the extruder is: zone 1 temperature 190°C, zone 2 temperature 200°C, zone 3 temperature 215°C, zone 4 temperature 220°C, zone 5 temperature 230°C, zone 6 temperature 230°C, and head temperature 220°C.

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