Bamboo fiber modified polypropylene composite material filled with high-content bamboo fibers and imitating wood grains and preparation method of bamboo fiber modified polypropylene composite material

Abstract

The invention discloses a bamboo fiber modified polypropylene composite material filled with high-content bamboo fibers and imitating wood grains and a preparation method of the bamboo fiber modified polypropylene composite material. The composite material is composed of the following raw materials in percentage by weight: 30-60% of polypropylene; 45-50% of bamboo fiber; 5-10% of polyethylene powder; 0-10% of talcum powder; 0.2 to 0.8 percent of compatilizer; 0.5-2% of an antioxidant; 0.2 to 2% of a scratch-resistant auxiliary agent; 0.2 to 2% of an anti-UV agent; and 1-5% of a lubricant. The bamboo fiber is used for replacing traditional talcum powder, mineral filler and glass fiber, and a high-torque double-screw extruder and a multi-side feeding system are combined, so that the light-weight and high-strength polypropylene composite material can be obtained; in addition, due to the low fluidity of the composite material, a special wood-grain-like appearance can be obtained through a specific injection molding process under the condition that mold leather grains are not needed. The high-content bamboo fiber filled wood-grain-imitated polypropylene composite material for the automobile, prepared by the preparation method disclosed by the invention, has an appearance effect equal to that of a wood patch or wood leather grain by combining the later color and mold design, and has a wide application space in automotive interior products.

Description

Technical Field

[0001] The invention relates to a bamboo fiber modified polypropylene composite material filled with high content of bamboo fiber and imitating wood grain and a preparation method thereof. The obtained material has the characteristics of light weight, imitating flocking, high strength and the like, and belongs to the technical field of polymer material processing and modification. Background Art

[0002] In recent years, the national and local governments have issued various industrial policies to promote and facilitate the healthy development of the bamboo products manufacturing industry, and continue to advance the construction process of "replacing wood with bamboo" and "replacing plastic with bamboo". Bamboo is a fast-growing, renewable resource with a short growth cycle. It can generally be cut down in 3-5 years and has a high yield, which provides sufficient raw material guarantee for the production of bamboo fiber materials and meets the requirements of sustainable development. In addition, in the application fields of composite materials such as automobiles, aviation, and construction, the demand for high-performance, lightweight, and environmentally friendly materials is increasing. Bamboo fiber reinforced composite materials have the advantages of light weight, high strength, recyclability, and green environmental protection, which can meet the needs of these fields and have therefore received widespread attention.

[0003] Polypropylene, as the most widely used material in automotive interiors, is usually blended with other types of materials to prepare new interior materials with excellent performance and unique appearance. Summary of the invention

[0004] The present invention provides a bamboo fiber modified polypropylene composite material with high content of bamboo fiber filling and imitation wood grain and a preparation method thereof. The obtained material replaces part of talcum powder, mineral filler and glass fiber in the traditional material formula with bamboo fiber, and combines a high-torque twin-screw extruder and a multi-side feeding system to obtain a lightweight and high-strength bamboo fiber / polypropylene composite material; in addition, due to the low fluidity of the composite material, a special appearance of imitation wood grain can be obtained through a specific injection molding process without the need for mold leather grain.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A bamboo fiber-modified polypropylene composite material with high bamboo fiber content filling and imitation wood grain is made of the following raw materials in parts by weight:

[0007] Polypropylene 30-60 parts;

[0008] 45-50 parts of bamboo fiber;

[0009] 5-10 parts of polyethylene powder;

[0010] Talc 0-10 parts;

[0011] Compatibilizer 0.2-0.8 parts;

[0012] 0.5-2 parts of antioxidant;

[0013] 0.2-2 parts of scratch-resistant additive;

[0014] Anti-UV agent 0.2-2 parts;

[0015] 1-5 parts of lubricant.

[0016] The polypropylene material is one or more of homopolymer polypropylene and copolymer polypropylene, and the specific requirement is that the melt flow rate is between 10 and 15 g / 10 min at 230° C. and 2.16 kg.

[0017] The mesh numbers of the bamboo fiber are 500-1000 meshes and 1500-2000 meshes, and the adding ratio is strictly controlled within a range of 2:1 to 1:1.

[0018] The polyethylene powder material is one or more of LLDPE-8320, LLDPE-2650 or LLDPE-6101.

[0019] The talc powder material is one or more of 3000 mesh, 5000 mesh or 10000 mesh.

[0020] The compatibilizer is one or more of vinyl silane coupling agents A151, A171 or A172.

[0021] The antioxidant includes a primary antioxidant and a secondary antioxidant; the primary antioxidant is a hindered amine; the secondary antioxidant is a combination of one or more of phosphites, thiodipropionates and thiols.

[0022] The scratch-resistant additive is an amide scratch-resistant additive.

[0023] The anti-UV agent is a compound of one or more of benzophenone, benzotriazole and hindered amine.

[0024] The lubricant is a compound of one or more of zinc stearate, magnesium stearate and calcium stearate.

[0025] The above-mentioned bamboo fiber-modified polypropylene composite material with high content of bamboo fiber filling and imitation wood grain has the following specific steps:

[0026] (1) Polypropylene, polyethylene powder, talcum powder, lubricant, antioxidant, anti-UV additive and anti-scratch agent are mixed and stirred uniformly to obtain premix A. Two types of bamboo fibers (500-1000 mesh and 1500-2000 mesh) are mixed uniformly with compatibilizer aqueous solution to obtain premixes B and C respectively;

[0027] (2) Premix A is added to the main feed port of the twin-screw extruder, premix B is added from the side feed port 1 of the twin-screw extruder, and premix C is added from the side feed port 2, melt blended at 180-200°C, extruded, cooled, granulated, and dried to obtain the final product (see the relevant feeding position for details). Figure 1 );

[0028] (3) The processing temperatures of zones 1-11 of the twin-screw extruder in step (2) are 105°C, 135°C, 165°C, 175°C, 175°C, 185°C, 185°C, 195°C, 195°C, 190°C, 190°C, respectively. The main screw speed is 300-500r / min, the water tank temperature is 23°C-50°C, the melt temperature should be controlled within 200°C, the side feed port 1# should be placed after the melting section and before the mixing section of the twin-screw extruder; the side feed port 2# should be placed after the mixing section and before the metering section of the twin-screw extruder.

[0029] The advantages of the present invention are:

[0030] 1. By using bamboo fiber to replace traditional inorganic fillers, it plays a role in low-carbon emission reduction while ensuring the basic mechanical properties of the original composite materials.

[0031] 2. The polypropylene / bamboo fiber composite material prepared by the method of the present invention has a bamboo fiber content in the range of 0-55wt%, and the maximum content of 55wt% has basically reached the plant fiber filling amount of the hot-pressed plant fiber felt board, and the material can be injection molded, providing more possibilities for the category of part design.

[0032] 3. The polypropylene / bamboo fiber composite material prepared by the present invention can be designed with different appearances by combining a specific mold and injection molding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The appearance effects of Example 1 and Comparative Example 1;

[0034] Figure 2 This is the appearance effect of Example 3 and Example 4;

[0035] Figure 3 This is the appearance effect of the sample of Example 1;

[0036] Figure 4 This is the appearance effect of the sample of Example 4. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below by way of examples and comparative examples, but the present invention is not limited to the scope of the examples.

[0038] The composite material formulas of the embodiments and comparative examples are shown in Table 1. The specific production and processing methods and the processing temperature of the extruder are shown above and will not be described in detail here.

[0039] Table 1 Material composition of Examples 1-4 and Comparative Examples 1-2 (percent by weight)

[0040]

[0041]

[0042] Table 2 Material performance test results of Examples 1-4 and Comparative Examples 1-2

[0043]

[0044] From the material performance test results of Example 1 and Example 2, it can be seen that as the bamboo fiber content in the material formula increases from 20wt% to 30wt%, the bending modulus of the material increases by 6.25%, the tensile strength remains basically unchanged, but the impact strength and notched impact strength decrease by 5.6% and 6.7% respectively. At the same time, Example 3 and Example 4 also present the same change trend.

[0045] From the test results of material properties of Example 2 and Example 3: both are 40wt% filled materials, Example 2 is 30wt% bamboo fiber + 10wt% talcum powder, and Example 3 is 40wt% bamboo fiber. The latter has a smaller density and ash content, and has an overall weight reduction effect of 3.7%. In addition, the bending modulus of the two is basically the same, but the tensile strength, impact strength and notched impact strength of Example 3 are significantly reduced. Similarly, the same argument can be drawn by combining Example 1 and Comparative Example 1, and Example 3 and Comparative Example 2.

[0046] Combined with material properties and sample and sample appearance (see Figure 1 , 2 , 3, 4) It can be seen that when the bamboo fiber content increases, under the same injection molding process, the appearance of the sample changes significantly, and the number and shape of wood grain waves are greatly improved. From the appearance of the parts, the appearance of Example 1 is the best, and the effect of imitating wood grain has been achieved. This effect can be achieved only by materials and processes, and no additional process treatment is required. It not only greatly reduces the production time, but also reduces the production cost, which has a significant effect on reducing the overall cost of automotive parts.

Claims

1. A bamboo fiber-modified polypropylene composite material filled with high content of bamboo fiber and imitating wood grain, characterized in that: Made from the following raw materials in parts by weight: Polypropylene 30-60 parts; 45-50 parts of bamboo fiber; 5-10 parts of polyethylene powder; Talc 0-10 parts; Compatibilizer 0.2-0.8 parts; 0.5-2 parts of antioxidant; 0.2-2 parts of scratch-resistant additive; Anti-UV agent 0.2-2 parts; 1-5 parts of lubricant.

2. The bamboo fiber-modified polypropylene composite material with high bamboo fiber content filling and imitation wood grain according to claim 1, characterized in that: The polypropylene material is one or more of homopolymer polypropylene and copolymer polypropylene, and the specific requirement is that the melt flow rate is between 10 and 15 g / 10 min at 230° C. and 2.16 kg.

3. The bamboo fiber-modified polypropylene composite material with high bamboo fiber content filling and imitation wood grain according to claim 1, characterized in that: The mesh numbers of the bamboo fiber are 500-1000 meshes and 1500-2000 meshes, and the addition ratio is 2:1 to 1:

1.

4. The bamboo fiber-modified polypropylene composite material with high bamboo fiber content filling and imitation wood grain according to claim 1, characterized in that: The polyethylene powder material is one or more of LLDPE-8320, LLDPE-2650 or LLDPE-6101.

5. The bamboo fiber-modified polypropylene composite material with high bamboo fiber content filling and imitation wood grain according to claim 1, characterized in that: The talc powder material is one or more of 3000 mesh, 5000 mesh or 10000 mesh.

6. The bamboo fiber-modified polypropylene composite material with high bamboo fiber content filling and imitation wood grain according to claim 1, characterized in that: The compatibilizer is one or more of vinyl silane coupling agents A151, A171 or A172.

7. The bamboo fiber-modified polypropylene composite material with high bamboo fiber content filling and imitation wood grain according to claim 1, characterized in that: The antioxidant comprises a primary antioxidant and a secondary antioxidant; the primary antioxidant is selected from hindered amines; the secondary antioxidant is a combination of one or more of phosphites, thiodipropionates and thiols.

8. The bamboo fiber-modified polypropylene composite material with high bamboo fiber content filling and imitation wood grain according to claim 1, characterized in that: The scratch-resistant additive is an amide scratch-resistant additive.

9. The bamboo fiber-modified polypropylene composite material with high bamboo fiber content filling and imitation wood grain according to claim 1, characterized in that: The anti-UV agent is a compound of one or more of benzophenone, benzotriazole and hindered amine; the lubricant is a compound of one or more of zinc stearate, magnesium stearate and calcium stearate.

10. The method for preparing the bamboo fiber-modified polypropylene composite material with high bamboo fiber content filling and imitation wood grain according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: polypropylene, talcum powder, polyethylene powder, lubricant, antioxidant, anti-UV additive and anti-scratch agent are mixed and stirred to obtain premix A. Two types of bamboo fibers (500-1000 mesh and 1500-2000 mesh) are respectively mixed with a compatibilizer aqueous solution to obtain premixes B and C; Step 2: Add premix A to the main feed port of the twin-screw extruder, add premix B from the 1# side feed port of the twin-screw extruder, and add premix C from the 2# side feed port. After melt blending at 180-200° C., extrude, cool, granulate, and dry to obtain the final product.

11. The method for preparing a bamboo fiber-modified polypropylene composite material with high bamboo fiber content filling and imitation wood grain according to claim 10, characterized in that: The processing temperatures of zones 1-11 of the twin-screw extruder involved are 105°C, 135°C, 165°C, 175°C, 175°C, 185°C, 185°C, 195°C, 195°C, 190°C, 190°C, respectively; the main screw speed is 300-500r / min, the water tank temperature is 23°C-50°C, and the melt temperature should be controlled within 200°C; The side feed port 1# should be placed after the melting section and before the mixing section of the twin-screw extruder; The side feed port 2# should be placed after the mixing section and before the metering section of the twin-screw extruder.

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