Scratch-resistant easily-colored polypropylene composite material as well as preparation method and application thereof

Abstract

The invention relates to a scratch-resistant easily-colored polypropylene composite material as well as a preparation method and application thereof, and belongs to the technical field of compositions of high-molecular compounds. The scratch-resistant easily-colored polypropylene composite material comprises the following components in parts by weight: 50-99 parts of polypropylene resin, 0-20 parts of a toughening agent, 0-25 parts of a filler, 0.05-1.1 parts of crystalline flake graphite and 0.5-4 parts of a scratch-resistant agent, the crystalline flake graphite comprises crystalline flake graphite A and crystalline flake graphite B, and the mesh number of the crystalline flake graphite A is greater than or equal to 1000; the mesh number of the crystalline flake graphite B is smaller than or equal to 400, and the space between the lamellar structures of the crystalline flake graphite B is filled with a scratch-resistant agent. The polypropylene composite material not only has excellent scratch resistance, but also has good coloring performance.

Description

Technical Field

[0001] The invention relates to the technical field of polymer compound compositions, and in particular to a scratch-resistant and easily colored polypropylene composite material, and a preparation method and application thereof. Background Art

[0002] Polypropylene is a polymer formed by free radical polymerization of propylene monomers. Due to its excellent electrical insulation, chemical corrosion resistance, heat resistance and fatigue resistance, it is widely used in the fields of automotive industry parts, electronic and electrical, packaging materials, pipes and fittings, etc., especially in automotive accessories, where its usage is much higher than other types of plastics. However, due to factors such as the high low-temperature brittleness and poor aging resistance of polypropylene, it is often necessary to perform toughening and filling modifications on it to better meet the application requirements of automotive accessories. At the same time, since automotive parts generally need to go through many links such as transportation, placement, and assembly from the manufacturer to the vehicle manufacturer, especially automotive interior parts, after being loaded on the vehicle and used by consumers, they will inevitably be scratched by sharp objects (such as keys), which will cause the polypropylene material to yield under the action of normal force, sliding force or lateral force, resulting in brittle failure and scratches, which will seriously affect the overall aesthetics of automotive interior parts.

[0003] In order to reduce the impact on the aesthetics of automotive interior parts during use, it is usually necessary to add scratch resistant agents to polypropylene materials to improve their scratch resistance. At present, the most widely used scratch resistant agents in modified polypropylene materials are amide scratch resistant agents or silicone scratch resistant agents. Among them, amide scratch resistant agents represented by erucamide or oleamide can quickly migrate to the surface of the material to form a thin lubricating layer and give the material good scratch resistance, but they are easy to make the surface of the parts sticky and easy to emit volatile gases; while silicone scratch resistant agents represented by silicone have poor compatibility with polypropylene, and as their dosage increases, they are easy to cause appearance problems such as flow marks or bright prints on polypropylene parts.

[0004] In order to solve the problem of the above-mentioned commonly used scratch-resistant agents, people began to look for suitable scratch-resistant synergists to reduce the amount of amide or silicone scratch-resistant agents, while effectively improving the scratch resistance of polypropylene materials. For example, the prior art (CN112480551A) discloses a polypropylene composition and a preparation method thereof, which uses flake graphite as a scratch-resistant synergist and utilizes the plasticity and lubricity of flake graphite to improve the surface scratch resistance of polypropylene materials. Although the automotive interior parts prepared with the polypropylene composition have improved the scratch resistance to a certain extent, it is still difficult to meet the higher appearance effect requirements of consumers for automotive interior parts. At the same time, in actual production, different color powders are often required to be added to meet consumers' demand for the diversity of colors of automotive interior parts, and the coloring performance of existing scratch-resistant polypropylene materials is poor. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a scratch-resistant and easily colored polypropylene composite material and a preparation method and application thereof.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a scratch-resistant and easily colored polypropylene composite material, comprising the following components by weight: 50 to 99 parts of polypropylene resin, 0 to 20 parts of toughening agent, 0 to 25 parts of filler, 0.05 to 1.1 parts of flake graphite, and 0.5 to 4 parts of scratch-resistant agent;

[0008] The flake graphite includes flake graphite A and flake graphite B, the mesh number of the flake graphite A is ≥1000 meshes; the mesh number of the flake graphite B is ≤400 meshes, and the flake structures of the flake graphite B are filled with a scratch-resistant agent.

[0009] The present invention combines small flake graphite of a specific particle size with large flake graphite filled with a scratch-resistant agent between the lamella structures of a specific particle size, so that the small flake graphite can be used to improve the coloring performance of the polypropylene composite material, while making it easier for the scratch-resistant agent to drive the small flake graphite to migrate to the surface of the polypropylene composite material during the migration process, and the scratch-resistant agent between the lamellae of the large flake graphite can be used to quickly migrate to the surface of the polypropylene composite material to form a lubricating layer, and the small flake graphite can also be better dispersed between the large flake graphite to form a continuous graphite heat-conducting layer, thereby effectively dispersing the heat generated when the polypropylene composite material rubs against metal or other sharp hard objects, thereby significantly improving the scratch resistance of the polypropylene composite material.

[0010] The mass fraction of the polypropylene resin in the scratch-resistant and easily colored polypropylene composite material is greater than or equal to 45%, and the polypropylene resin can be at least one of homopolymer polypropylene, block copolymer polypropylene or random copolymer polypropylene; the polypropylene resin adopts the ISO1133-2011 standard, and the melt mass flow rate at 230°C and 2.16kg can be 10 to 30g / 10min. The above-mentioned toughening agent is a conventional toughening agent suitable for the polypropylene system, and the toughening agent adopts the ISO1133-2011 standard, and the melt mass flow rate at 190°C and 2.16kg can be 0.1 to 10g / 10min.

[0011] Optionally, the weight proportion of the polypropylene resin in the scratch-resistant and easily colored polypropylene composite material can be 55, 60, 65, 70, 75, 80, 85, 90, or 95 parts; the weight proportion of the toughening agent can be 2, 4, 6, 8, 10, 12, 14, 16, or 18 parts; the weight proportion of the filler can be 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, or 24 parts; the weight proportion of the flake graphite can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9 parts; and the scratch-resistant agent can be 1, 1.5, 2, 2.5, 3, or 3.5 parts.

[0012] In addition, the mesh number of the above-mentioned flake graphite A ≥1000 mesh means that the particle size of the flake graphite A is less than or equal to the sieve aperture (13 μm) corresponding to the 1000 mesh sieve, and the mesh number of the flake graphite B ≤400 mesh means that the particle size of the flake graphite B is greater than or equal to the sieve aperture (38 μm) corresponding to the 400 mesh sieve.

[0013] As a preferred embodiment of the scratch-resistant and easily colorable polypropylene composite material of the present invention, the scratch-resistant and easily colorable polypropylene composite material comprises the following components in parts by weight: 60 to 80 parts of polypropylene resin, 5 to 15 parts of toughening agent, 10 to 20 parts of filler, 0.1 to 1 part of flake graphite, and 1 to 3 parts of scratch-resistant agent.

[0014] As a preferred embodiment of the scratch-resistant and easily colorable polypropylene composite material of the present invention, the mesh size of the flake graphite A is 1000-2000 mesh, which is equivalent to an average particle size of the flake graphite A of 6.5-13 μm.

[0015] As a preferred embodiment of the scratch-resistant and easily colorable polypropylene composite material of the present invention, the mesh size of the flake graphite B is 325-400 meshes, which is equivalent to an average particle size of the flake graphite B of 38-45 μm.

[0016] As a preferred embodiment of the scratch-resistant and colorable polypropylene composite material of the present invention, the mass ratio of the flake graphite A to the flake graphite B is 1:(0.3-3). Optionally, the mass ratio of the flake graphite A to the flake graphite B can be 1:0.4, 1:0.6, 1:0.8, 1:1, 1:1.5, 1:2, 1:2.5.

[0017] As a preferred embodiment of the scratch-resistant and colorable polypropylene composite material of the present invention, the flake graphite B is obtained by mixing flake graphite with a mesh number of ≤400 and a part of the scratch-resistant agent and then melt-extruding. Optionally, the mass ratio of flake graphite with a mesh number of ≤400 in the flake graphite B to the part of the scratch-resistant agent is (0.1-1):(0.001-0.008), preferably (0.2-0.8):0.004, specifically 0.15:0.004, 0.25:0.004, 0.3:0.004, 0.35:0.004, 0.4:0.004, 0.5:0.004, 0.6:0.004, 0.7:0.004, 0.9:0.004.

[0018] As a preferred embodiment of the scratch-resistant and easily colorable polypropylene composite material of the present invention, the toughening agent includes at least one of ethylene-octene copolymer, ethylene-butene copolymer, ethylene propylene diene monomer rubber, and ethylene-vinyl acetate copolymer.

[0019] As a preferred embodiment of the scratch-resistant and easily colorable polypropylene composite material of the present invention, the filler is at least one of talcum powder, calcium carbonate, mica powder, barium sulfate and wollastonite.

[0020] As a preferred embodiment of the scratch-resistant and easily colorable polypropylene composite material of the present invention, the scratch-resistant agent is at least one of an amide scratch-resistant agent and a silicone scratch-resistant agent; specifically, the scratch-resistant agent is at least one of vinyl bisstearamide (EBS), oleamide, erucamide, and silicone.

[0021] As a preferred embodiment of the scratch-resistant and colorable polypropylene composite material of the present invention, the components of the scratch-resistant and colorable polypropylene composite material also include 0.1 to 3 parts by weight of a processing aid, and the processing aid includes at least one of an antioxidant, a heat stabilizer, and a light stabilizer.

[0022] As a preferred embodiment of the scratch-resistant and colorable polypropylene composite material of the present invention, the components of the scratch-resistant and colorable polypropylene composite material also include carbon black, and the mass fraction of the carbon black relative to the scratch-resistant and colorable polypropylene composite material is 0.5% to 1.5%.

[0023] In a second aspect, the present invention provides a method for preparing the above-mentioned scratch-resistant and easily colored polypropylene composite material, which comprises the following steps: mixing the components evenly and then melt-extruding to obtain the scratch-resistant and easily colored polypropylene composite material; wherein the melt extrusion can be specifically carried out using a twin-screw extruder, the aspect ratio of the twin-screw extruder is (36-48):1, and the temperature setting of the twin-screw extruder is: the temperature of zone 1 is 80-120°C, the temperature of zones 2 to 5 is 180-200°C, and the temperature of other zones is 200-230°C.

[0024] In a third aspect, the present invention provides the use of the scratch-resistant and easily colored polypropylene composite material in the preparation of automotive parts. Specifically, automotive parts refer to bumpers, interior trims (instrument panels, door trims, seats, steering wheels, etc.), engine peripheral parts (intake manifolds, cooling fans, fan covers, etc.), and electrical components such as wire insulation and battery housings.

[0025] In a fourth aspect, the present invention provides an automotive interior or exterior trim mainly made of the scratch-resistant and easily colorable polypropylene composite material.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention combines small flake graphite of a specific particle size with large flake graphite filled with a scratch-resistant agent between the lamella structures of a specific particle size, so that the small flake graphite can be used to improve the coloring performance of the polypropylene composite material, while the scratch-resistant agent can be more easily driven to migrate to the surface of the polypropylene composite material during the migration process, and the scratch-resistant agent between the lamellae of the large flake graphite can be used to quickly migrate to the surface of the polypropylene composite material to form a lubricating layer, and the small flake graphite can also be better dispersed between the large flake graphite to form a continuous graphite heat-conducting layer, thereby effectively dispersing the heat generated when the polypropylene composite material rubs against metal or other sharp hard objects, thereby significantly improving the scratch resistance of the polypropylene composite material, and at the same time having good coloring performance. DETAILED DESCRIPTION

[0028] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0029] Unless otherwise specified, other materials, reagents, etc. used in the examples and comparative examples can be obtained from commercial sources.

[0030] 1. Raw materials and reagents

[0031] Polypropylene resin 1: brand PP EP548R, manufacturer is CNOOC Shell;

[0032] Polypropylene resin 2: brand PP K9930 (GUANGZHOU), manufacturer is Guangzhou Petrochemical;

[0033] The toughening agent is ethylene-butene copolymer, brand name POE ENGAGE 7447, manufacturer is Dow;

[0034] The filler is talcum powder, brand TYT-777A, manufacturer is Beihai Tianyuan;

[0035] Flake graphite A1, mesh number is 1000 mesh, brand is flake graphite-1000, manufacturer is Qingdao Haiheda Graphite Co., Ltd.;

[0036] Flake graphite A2, mesh number is 2000 mesh, brand name is flake graphite-2000 mesh, manufacturer is Qingdao Xintianhe Carbon Materials Co., Ltd.;

[0037] Flake graphite B1, mesh number is 325 mesh, brand name is Flake Graphite-325 mesh, manufacturer is Qingdao Xintianhe Carbon Material Co., Ltd.;

[0038] Flake graphite B2, mesh number is 399 mesh, brand is flake graphite-399, manufacturer is Qingdao Haiheda Graphite Co., Ltd.;

[0039] Flake graphite C, mesh number is 500 mesh, brand name is flake graphite-500 mesh, manufacturer is Qingdao Xintianhe Carbon Materials Co., Ltd.;

[0040] The anti-scratch agent 1 is erucamide, the brand is lubricant-erucamide, and the manufacturer is Sichuan Xipuheda;

[0041] The scratch resistant agent 2 is a silicone masterbatch (composed of carrier resin PP and dimethyl polysiloxane in a mass ratio of 1:1), the brand is BZPP301, and the manufacturer is Chongqing Baozhuan;

[0042] The processing aid is prepared by compounding antioxidant 168, antioxidant 1010 and hindered amine light stabilizer (LA-402AF) in a mass ratio of 1:1:1, wherein antioxidant 168, antioxidant 1010 and hindered amine light stabilizer are all commercially available.

[0043] 2. Examples 1 to 12 and Comparative Examples 1 to 5

[0044] Table 1 Weight percentage of each component of the scratch-resistant and colorable polypropylene composite material in Examples 1 to 12

[0045]

[0046]

[0047] In Example 4 in Table 1, 4 parts by weight of the scratch-resistant agent 2 (ie, silicone masterbatch) is added, which is equivalent to adding 2 parts by weight of dimethylpolysiloxane.

[0048] The preparation method of the scratch-resistant and easily colored polypropylene composite material in the above-mentioned embodiments 1 to 12 comprises the following steps: according to the formula, firstly, a part of the scratch-resistant agent (accounting for 0.2% of the mass fraction of the total scratch-resistant agent) is mixed with flake graphite B, and then melt-extruded through a twin-screw extruder; then, the mixture is uniformly mixed with polypropylene resin, toughening agent, filler, flake graphite A, the remaining scratch-resistant agent and processing aid, and then added into a twin-screw extruder for melt-extruded to obtain a scratch-resistant and easily colored polypropylene composite material; wherein, the aspect ratio of the twin-screw extruder is 48:1, and the temperature setting of the twin-screw extruder is: the temperature of zone 1 is 80-120°C, the temperature of zones 2 to 5 is 180-200°C, and the temperature of other zones is 200-230°C.

[0049] Table 2 Weight percentage of each component of the scratch-resistant and colorable polypropylene composite material in Comparative Examples 1 to 4

[0050]

[0051]

[0052] The preparation method of the scratch-resistant and easily colored polypropylene composite material in the above-mentioned comparative examples 1 to 4 comprises the following steps: according to the formula, firstly, a part of the scratch-resistant agent (accounting for 0.2% by mass of the total scratch-resistant agent) is mixed with flake graphite B and then melt-extruded through a twin-screw extruder, and then, the mixture is mixed evenly with polypropylene resin, toughening agent, filler, flake graphite A or flake graphite C, the remaining scratch-resistant agent and processing aid, and then added into a twin-screw extruder for melt-extruded to obtain a scratch-resistant and easily colored polypropylene composite material; wherein, the aspect ratio of the twin-screw extruder is 48:1, and the temperature setting of the twin-screw extruder is: the temperature of zone 1 is 80-120°C, the temperature of zones 2 to 5 is 180-200°C, and the temperature of other zones is 200-230°C.

[0053] Comparative Example 5

[0054] A comparative example of the scratch-resistant and easily colored polypropylene composite material of the present invention, the components of the polypropylene composite material are basically the same as those of Example 1 (i.e., 70 parts by weight of polypropylene resin 1, 10 parts by weight of toughening agent, 20 parts by weight of filler, 0.4 parts by weight of flake graphite A1, 0.4 parts by weight of flake graphite B1, 2 parts by weight of scratch-resistant agent, and 0.6 parts by weight of processing aid), the difference being that the preparation method thereof comprises the following steps:

[0055] According to the formula, polypropylene resin, toughening agent, filler, flake graphite A, flake graphite B, scratch-resistant agent and processing aid are directly mixed together and then added into a twin-screw extruder for melt extrusion to obtain a scratch-resistant and easily colorable polypropylene composite material; wherein, the aspect ratio of the twin-screw extruder is 48:1, and the temperature setting of the twin-screw extruder is: the temperature of zone 1 is 80-120°C, the temperature of zones 2 to 5 is 180-200°C, and the temperature of other zones is 200-230°C.

[0056] 3. Performance testing

[0057] 1) Scratch resistance: The polypropylene composite materials in the embodiments and comparative examples were tested on injection molded samples using the cross-hatch method according to Volkswagen PV3952-2002 standard, with a needle contact load of 10N, a needle diameter of 1mm, and a scratching speed of 1000mm / min; the severity of the scratch was determined by measuring the change in the color whiteness value L (△L) before and after the scratch using a colorimeter. The smaller the △L value, the lighter the surface scratch, indicating that the scratch resistance of the polypropylene composite material is better.

[0058] 2) Coloring performance: The polypropylene composite materials in each embodiment and comparative example were randomly divided into group A and group B, wherein the polypropylene composite materials in group A were directly injection molded into samples and the L value (L A ); the polypropylene composite material in group B was added with carbon black (the mass fraction of carbon black relative to the polypropylene composite material was 1%) and then injection molded into a sample and the L value (L B ), △L=L B -L A , three groups were tested to obtain △L1, △L2, and △L3, and the average value of the three groups of △L values ​​((△L1+△L2+△L3) / 3) was used to evaluate the coloring performance of the polypropylene composite material. The larger the average value, the better the coloring performance of the polypropylene composite material.

[0059] Table 3 Properties of scratch-resistant and colorable polypropylene composite materials in various embodiments and comparative examples

[0060] serial number Scratch resistance Coloring performance Example 1 0.43 65.3 Example 2 0.48 64.5 Example 3 0.38 66.4 Example 4 0.41 65.1 Example 5 0.45 65.2 Example 6 0.65 63.2 Example 7 0.56 62.4 Example 8 0.41 63.5 Example 9 0.24 63.1 Example 10 0.73 63.1 Embodiment 11 0.71 63.2 Example 12 0.67 63.5 Comparative Example 1 1.02 56.3 Comparative Example 2 1.34 51.2 Comparative Example 3 0.89 45.5 Comparative Example 4 1.23 40.3 Comparative Example 5 1.03 43.1

[0061] According to the data in Table 3, the color whiteness value change △L of the polypropylene composite materials in Examples 1 to 12 before and after scratching is less than or equal to 0.73, and the average value of the whiteness value change △L after coloring is greater than or equal to 62.4, indicating that the polypropylene composite material of the present invention not only has excellent scratch resistance, but also has good coloring performance. According to Comparative Examples 1 and 2, it can be found that adding small-particle flake graphite A or large-particle flake graphite B alone is difficult to effectively improve the scratch resistance and coloring performance of the polypropylene composite material; at the same time, it can be seen from Comparative Examples 3 and 4 that when flake graphite A is compounded with flake graphite C, although the scratch resistance of the polypropylene composite material can be improved to a certain extent, it is difficult to improve its coloring performance; and when flake graphite B is compounded with flake graphite C, the improvement effect on the scratch resistance and coloring performance of the polypropylene composite material is extremely limited, which fully illustrates that only the combination of small flake graphite of a specific particle size and large flake graphite of a specific particle size can effectively improve the scratch resistance and coloring performance of the polypropylene composite material. In addition, according to Comparative Example 5, when flake graphite A, flake graphite B and the scratch resistant agent are directly mixed with other components and then melt-extruded (at this time, due to the presence of other components, the scratch resistant agent is difficult to fill between the lamellar structures of flake graphite B), the scratch resistance and coloring properties of the polypropylene composite material cannot be significantly improved.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A scratch-resistant and easily colored polypropylene composite material, characterized in that: By weight, it includes the following components: 50-99 parts of polypropylene resin, 0-20 parts of toughening agent, 0-25 parts of filler, 0.05-1.1 parts of flake graphite, 0.5-4 parts of scratch resistance agent; The flake graphite includes flake graphite A and flake graphite B, the mesh number of the flake graphite A is ≥1000 meshes; the mesh number of the flake graphite B is ≤400 meshes, and the flake structures of the flake graphite B are filled with a scratch-resistant agent.

2. The scratch-resistant and easily colored polypropylene composite material according to claim 1, characterized in that: The invention comprises the following components by weight: 60 to 80 parts of polypropylene resin, 5 to 15 parts of toughening agent, 10 to 20 parts of filler, 0.1 to 1 part of flake graphite and 1 to 3 parts of scratch-resistant agent.

3. The scratch-resistant and easily colored polypropylene composite material according to claim 1, characterized in that: The mesh number of the flake graphite A is 1000-2000 meshes.

4. The scratch-resistant and easily colored polypropylene composite material according to claim 1, characterized in that: The mesh number of the flake graphite B is 325-400 meshes.

5. The scratch-resistant and easily colorable polypropylene composite material according to claim 1, characterized in that: The mass ratio of the flake graphite A to the flake graphite B is 1:(0.3-3).

6. The scratch-resistant and easily colorable polypropylene composite material according to claim 1, characterized in that: The flake graphite B is obtained by mixing flake graphite with a mesh number of ≤400 meshes with a scratch-resistant agent and then melt-extruding the mixture.

7. The scratch-resistant and easily colorable polypropylene composite material according to any one of claims 1 to 6, characterized in that: Satisfy at least one of the following: (1) The toughening agent includes at least one of ethylene-octene copolymer, ethylene-butene copolymer, ethylene propylene diene monomer rubber, and ethylene-vinyl acetate copolymer; (2) The filler is at least one of talc, calcium carbonate, mica powder, barium sulfate, and wollastonite; (3) The scratch resistant agent is at least one of an amide scratch resistant agent and a silicone scratch resistant agent; (4) The components of the scratch-resistant and easily colored polypropylene composite material also include a processing aid, and the processing aid includes at least one of an antioxidant, a heat stabilizer, and a light stabilizer; (5) The invention also includes carbon black, wherein the mass fraction of the carbon black relative to the scratch-resistant and colorable polypropylene composite material is 0.5% to 1.5%.

8. The method for preparing the scratch-resistant and easily colorable polypropylene composite material according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: mixing the components uniformly and then melting and extruding them to obtain the scratch-resistant and easily colored polypropylene composite material.

9. Use of the scratch-resistant and easily colorable polypropylene composite material according to any one of claims 1 to 7 in the preparation of automotive parts.

10. An automobile interior or exterior decoration mainly made of the scratch-resistant and easily colorable polypropylene composite material according to any one of claims 1 to 7.

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