Polypropylene composition containing plant fibers, and preparation method therefor and use thereof

Abstract

A polypropylene composition containing plant fibers, and a preparation method therefor and the use thereof. The polypropylene composition containing plant fibers comprises the following components in parts by weight: 60-75 parts of a polypropylene, 10-35 parts of plant fibers, 1-5 parts of a compatilizer, 1-4 parts of a phenolic compound and 0-5 parts of an auxiliary agent. The polypropylene composition containing plant fibers has a high plant fiber filling rate and excellent mechanical properties; in addition, the water absorption rate of a material, which has been subjected to secondary processing, is not sharply increased and is maintained within a relatively stable range, and the polypropylene composition has important practical application value.

Description

A polypropylene composition containing plant fiber and its preparation method and application Technical Field

[0001] The present application belongs to the field of polymer materials, and specifically relates to a polypropylene composition containing plant fibers, a preparation method, and an application thereof. Background Art

[0002] With the rapid development of the automotive industry in recent years, lightweighting, quality improvement, energy conservation, environmental protection, and functionalization have become key goals. Polypropylene, a versatile engineering plastic, is a key lightweight automotive material due to its low price, lightweight, solvent resistance, recyclability, and non-toxicity.

[0003] Combining polypropylene with plant fibers (such as wood fiber, rice husk fiber, and hemp fiber) creates plant-fiber-containing polypropylene composites. These composites leverage the advantages of polypropylene (such as low cost, good processing and mechanical properties) with the characteristics of plant fibers (such as lightweight, environmentally friendly, and renewable) to achieve a variety of applications. Among them, they can be used in automotive interior components such as seat backs, door panels, and dashboard trim. Because these composites combine the advantages of polypropylene and plant fibers, they can replace traditional plastic materials to some extent, reducing dependence on non-renewable resources and minimizing environmental impact.

[0004] For example, the patent document CN115521534A discloses a polypropylene composition and its preparation method and application, the components of which include: polypropylene resin, p-toluidine, compatibilizer, polyethylene, plant cellulose, antioxidant, and weathering agent. Such polypropylene composition can be secondary processed, and the performance of the secondary processing can also be well maintained. However, in specific use, it is found that after the secondary processing of conventional polypropylene composite materials containing plant fibers, such composite materials can generally maintain a certain degree of original mechanical properties before use, including tensile and impact properties. However, the water absorption rate of the material after the secondary processing will increase sharply, especially when it is used for a long time in a relatively humid environment. The water absorption rate of the composite material after the secondary processing will increase significantly, thereby affecting the mechanical properties of the actual material, which is not conducive to the actual use and recycling of the material. Summary of the Invention

[0005] The present application provides a polypropylene composition containing plant fibers, a preparation method thereof, and an application thereof, in order to solve the problem that the water absorption rate of the polypropylene composition containing plant fibers increases sharply after secondary processing.

[0006] The present application provides a polypropylene composition containing plant fibers, the raw materials for its preparation comprising the following components in parts by weight: 60-75 parts of polypropylene, 10-35 parts of plant fibers, 1-5 parts of a compatibilizer, 1-4 parts of a phenolic acid compound, and 0-5 parts of an additive.

[0007] In some embodiments, the plant fiber includes surfactant-modified plant fiber and / or unmodified plant fiber, and the plant fiber includes at least one of bamboo fiber, flax fiber, pine fiber, palm fiber, cotton stalk fiber, wheat straw fiber, rice straw fiber, and reed stalk fiber.

[0008] In some embodiments, the plant fiber includes flax fiber and bamboo fiber, and the mass ratio of the flax fiber to the bamboo fiber is 1:(0.5-4).

[0009] In some embodiments, the surfactant in the surfactant-modified plant fiber includes at least one of fatty alcohol polyoxyethylene ether, fatty alcohol polyether sulfate, and polycarboxylate surfactants.

[0010] In some embodiments, in the surfactant-modified plant fiber, the mass of the surfactant added during the process of using the surfactant to modify the plant fiber accounts for 0.1-4% of the mass of the plant fiber.

[0011] In some embodiments, the phenolic acid compound includes at least one of 6-hydroxy-2-naphthoic acid, 1-naphthol-2-carboxylic acid, p-hydroxybenzoic acid, 2,5-dihydroxybenzoic acid, and cinnamphenolic acid.

[0012] In some embodiments, the compatibilizer includes a maleic anhydride grafted polyolefin.

[0013] In some embodiments, at least one of the following is included:

[0014] The melt flow rate of the polypropylene is 2 to 6 g / 10 min at 230° C. and 2.16 kg, and the test standard is ISO1133-2005;

[0015] The auxiliary agent comprises 0.2-0.4 parts by weight of a phenolic primary antioxidant, 0.2-0.4 parts by weight of a phosphite secondary antioxidant and 0.4-0.8 parts by weight of an ultraviolet stabilizer.

[0016] The present application also provides a method for preparing the polypropylene composition containing plant fibers, comprising the following steps:

[0017] Polypropylene and a compatibilizer are mixed to obtain a first premix; plant fibers and / or surfactant-modified plant fibers, phenolic acid compounds and additives are mixed to obtain a second premix; the first premix and the second premix are evenly mixed, melt-blended, and extruded into granules to obtain the polypropylene composition.

[0018] The present application also provides application of the polypropylene composition containing plant fibers in the field of automobile interior decoration.

[0019] Compared with the prior art, this application has the following beneficial effects:

[0020] (1) The present application achieves a polypropylene composition having a high plant fiber filling rate and excellent mechanical properties by compounding multiple components such as polypropylene, plant fiber, compatibilizer, and phenolic acid compound. At the same time, the water absorption rate of the material after secondary processing does not increase sharply and remains in a relatively stable range, which has important practical application value.

[0021] (2) The preparation method of the polypropylene composition containing plant fibers of the present application is simple and easy to implement, and is suitable for mass production. DETAILED DESCRIPTION

[0022] This application provides the following technical solutions:

[0023] A polypropylene composition containing plant fibers comprises the following raw materials in parts by weight: 60-75 parts of polypropylene, 10-35 parts of plant fibers, 1-5 parts of a compatibilizer, 1-4 parts of a phenolic acid compound, and 0-5 parts of an auxiliary agent.

[0024] Phenolic acid compounds are a class of organic compounds with phenolic and carboxylic acid groups. Their molecular structures usually contain one or more benzene rings with one or more carboxylic acid groups attached to the benzene rings. Phenolic acid compounds are added to polypropylene compositions containing plant fibers, which have the following characteristics: (1) Phenolic acid compounds have active functional groups that can react with hydroxyl groups in plant fibers to form cross-linked structures. Such cross-linking can enhance the strength and temperature resistance of the material; (2) After secondary processing, the material is susceptible to oxidation, resulting in an increase in water absorption. By introducing phenolic acid compounds, the phenolic acid compounds have excellent antioxidant properties and can effectively delay the aging process of the material and effectively slow down the aging rate of the material, thereby reducing the increase in water absorption after secondary processing; (3) Phenolic acid compounds can form stable chemical bonds in the material, enhance the molecular structure and stability of the material. At the same time, phenolic acid compounds have good water resistance and moisture resistance, can effectively block moisture from entering the material, reduce the increase in water absorption of the material, and help improve the long-term stability of the polypropylene composition containing plant fibers, reduce the performance degradation and water absorption increase of the material after secondary processing. (4) In addition, the addition of phenolic acid compounds also has a positive effect on the process performance of polypropylene compositions containing plant fibers. The small molecular structure of phenolic acid compounds can improve the processing stability and fluidity of the materials and reduce the problems of hygroscopic deformation and poor fluidity of the materials during processing, which is of great significance for achieving efficient production and reducing manufacturing costs.

[0025] The weight percentage of polypropylene in the present application is between 60-75 parts, and the weight percentage of plant fiber is between 10-35 parts. This ratio can fully utilize the advantages of polypropylene and plant fiber and achieve a balance in material properties. Within the above content range, by increasing the content of plant fiber, the strength, stiffness, and heat resistance of the composition can be improved, while reducing the amount of polypropylene used, achieving more efficient utilization of sustainable resources.

[0026] In some embodiments, the weight percentage of polypropylene can be 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 63, 74, 75, etc., as well as specific point values ​​between the above point values ​​and range values ​​consisting of any two of the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0027] In some embodiments, the weight proportion of plant fiber can be 12.5, 15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, 35, etc., as well as specific point values ​​between the above point values ​​and range values ​​consisting of any two of the above point values. Due to space limitations and for the sake of simplicity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0028] In some embodiments, the plant fiber-containing polypropylene composition is prepared from raw materials comprising the following components in parts by weight: 62-70 parts of polypropylene, 20-30 parts of plant fiber, 2-3.5 parts of compatibilizer, 1.5-2.5 parts of phenolic acid compound, and 0.2-1 part of additive.

[0029] In some embodiments, the phenolic acid compound includes at least one of 6-hydroxy-2-naphthoic acid, 1-naphthol-2-carboxylic acid, p-hydroxybenzoic acid, 2,5-dihydroxybenzoic acid, and cinnamphenolic acid.

[0030] The phenolic acid compounds mentioned above can achieve better bonding between the fibers and the matrix in the polypropylene composition by reacting with hydroxyl groups in materials such as plant fibers, thereby improving the strength and durability of the material.

[0031] In some embodiments, the phenolic acid compound is p-hydroxybenzoic acid, which has excellent antioxidant properties and can more effectively inhibit the oxidation reaction of oxygen on materials.

[0032] In some embodiments, the phenolic acid compound is 2,5-dihydroxybenzoic acid.

[0033] In some embodiments, the mass ratio of the phenolic acid compound to the plant fiber is 1:6-30.

[0034] In some embodiments, the mass ratio of the phenolic acid compound to the plant fiber is 1:10-20.

[0035] In some embodiments, the plant fiber includes at least one of unmodified plant fiber and surface-modified plant fiber; the plant fiber includes at least one of bamboo fiber, flax fiber, pine fiber, palm fiber, cotton stalk fiber, wheat straw fiber, rice straw fiber, and reed stalk fiber.

[0036] In some embodiments, the plant fiber includes flax fiber and bamboo fiber, and the mass ratio of the flax fiber to the bamboo fiber is 1:(0.5-4).

[0037] In some embodiments, the mass ratio of the flax fiber to the bamboo fiber can be (1:0.5), (1:1), (1:1.5), (1:2), (1:2.5), (1:3), (1:3.5), (1:4), (1:4.5), (1:5), etc., as well as specific point values ​​between the above point values ​​and range values ​​consisting of any two of the above point values. Due to space limitations and for the sake of brevity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0038] In some embodiments, the mass ratio of the flax fiber to the bamboo fiber is 1:(1-2).

[0039] The plant fibers added to the polypropylene composition of the present application have good hygroscopicity and humidity-regulating properties. They can absorb and release moisture in the air, help regulate the humidity and temperature of the material, and also help improve the comfort and stability of the material. Moreover, plant fibers such as flax fiber, bamboo fiber and pine fiber have good plasticity and workability during processing, and they are well compatible with matrix materials such as polypropylene.

[0040] By mixing flax fiber and bamboo fiber in the above specific weight ratio, the mechanical properties of the polypropylene composition can be optimized and the strength, stiffness and toughness of the material can be balanced.

[0041] In some embodiments, the surface modification includes modifying the plant fiber with a surfactant, and the surfactant includes at least one of fatty alcohol polyoxyethylene ether, fatty alcohol polyether sulfate, and polycarboxylate surfactants.

[0042] In some embodiments, the general formula of the fatty alcohol polyoxyethylene ether is RO(CH2CH2O)nH, where R is generally a saturated or unsaturated C12-C18 hydrocarbon group, which can be a straight-chain hydrocarbon group or a branched hydrocarbon group, and n is the addition number of ethylene oxide, n≥2, such as dodecaned / tetradeceded fatty alcohol polyoxyethylene ether (5EO), dodecaned / tetradeceded fatty alcohol polyoxyethylene ether (7EO), dodecaned / tetradeceded fatty alcohol polyoxyethylene ether (9EO), etc.

[0043] In some embodiments, the general formula of the fatty alcohol polyether sulfate is RO(CH2CH2O)nSO3M, where R is a saturated or unsaturated C12-C14 hydrocarbon group, which can be a linear hydrocarbon group or a branched hydrocarbon group, n is the addition number of ethylene oxide, n≥2, and M is a cation, including sodium ions, ammonium ions, etc., such as being selected from any one or more of lauryl / tetradecyl fatty alcohol polyoxyethylene ether (2EO) sodium sulfate, lauryl / tetradecyl fatty alcohol polyoxyethylene ether (3EO) sodium sulfate, lauryl / tetradecyl fatty alcohol polyoxyethylene ether (5EO) sodium sulfate, lauryl / tetradecyl fatty alcohol polyoxyethylene ether (7EO) sodium sulfate, lauryl / tetradecyl fatty alcohol polyoxyethylene ether (9EO) sodium sulfate, and alkyl alcohol polyoxyethylene (1-4) ether ammonium sulfate (DNS-360).

[0044] In some embodiments, the polycarboxylates include at least one of polyacrylamide carboxylates and polymethacrylates. In some embodiments, the polycarboxylates include but are not limited to sodium polyacrylamide carboxylate, potassium polyacrylamide carboxylate, sodium polymethacrylate, and potassium polymethacrylate.

[0045] In some embodiments, in the surfactant-modified plant fiber, the surfactant added during the process of using the surfactant to modify the plant fiber accounts for 0.1-4% of the mass of the plant fiber.

[0046] In some embodiments, the method for preparing the surfactant-modified plant fiber comprises the following steps:

[0047] (1) Immerse the plant fiber in a cleaning agent to clean and remove impurities, then rinse with water and dry;

[0048] (2) adding the plant fiber dried in step (1) into a surfactant solution to carry out a surface modification reaction, and drying to obtain the surfactant-modified plant fiber.

[0049] The amount of surfactant used is the amount commonly used in the art. In some embodiments, the surfactant added during the modification process accounts for 0.1-4% of the mass of the plant fiber. In some embodiments, the surfactant added during the modification process accounts for 1.5-4% of the mass of the plant fiber.

[0050] In some embodiments, the cleaning agent in step (1) is a sodium hexametaphosphate aqueous solution, and the mass percentage of sodium hexametaphosphate in the sodium hexametaphosphate aqueous solution is 4-8%.

[0051] In some embodiments, the mass ratio of the plant fiber to the cleaning agent in step (1) is 1:15-30.

[0052] In some embodiments, the cleaning and impurity removal time in step (1) is 5-30 minutes.

[0053] In some embodiments, the drying temperature in steps (1) and (2) is 80-120°C.

[0054] In some embodiments, the surface modification reaction in step (2) is a water bath reaction.

[0055] In some embodiments, the temperature of the surface modification reaction in step (2) is 70-90° C., and the time of the surface modification reaction is 10-20 min.

[0056] In some embodiments, the mass ratio of the dried plant fiber to the surfactant solution in step (2) is 1:15-40.

[0057] Plant fibers usually have high hydrophilicity, while hydrophobic matrix materials such as polypropylene have low hydrophilicity. This application uses surfactant active pretreatment to allow the surfactant to be fully chemically adsorbed on the surface of the plant fibers, which can improve the compatibility between the plant fibers and polypropylene, increase the adhesion and interaction between them, and thus achieve better fiber reinforcement effects.

[0058] In some embodiments, the compatibilizer comprises a maleic anhydride graft. In some embodiments, the compatibilizer can be selected from maleic anhydride grafted polyolefin. In some embodiments, the compatibilizer comprises (or can be selected from) at least one of maleic anhydride grafted polyethylene and maleic anhydride grafted polypropylene.

[0059] Polypropylene and plant fibers have large differences in chemical properties and hydrophilicity, so their compatibility is limited. The above-mentioned compatibilizer can be introduced to help improve the compatibility between polypropylene and plant fibers, enhance the adhesion and interaction between them, which helps to improve the overall performance of the composition and ensure its stability and consistency during the secondary processing. Therefore, the polypropylene composition provided by the present application has a high plant fiber filling rate and excellent mechanical properties. At the same time, the water absorption rate of the material after secondary processing does not increase sharply, and is maintained in a relatively stable range, which has important practical application value.

[0060] Maleic anhydride-grafted polyethylene is an amphiphilic molecule with excellent compatibility. By introducing it into a polypropylene composition as a compatibilizer, it can significantly increase the compatibility between polypropylene and plant fibers, promoting mixing and interaction between the two, and balancing the material's impact resistance. Because maleic anhydride-grafted polyethylene is more fluid than maleic anhydride-grafted polypropylene, this increased fluidity helps to more evenly distribute stress under impact loading and slow crack propagation. In some embodiments, the compatibilizer is maleic anhydride-grafted polyethylene.

[0061] In some embodiments, the polypropylene includes homopolypropylene, and the melt flow rate of the polypropylene is 2 to 6 g / 10 min at 230° C. and 2.16 kg, and the test standard is ISO1133-2005.

[0062] In some embodiments, the auxiliary agent includes at least one of an antioxidant, a UV stabilizer, a toughening agent, a flame retardant, and a lubricant. In some embodiments, the auxiliary agent includes 0.2-0.4 parts by weight of a phenolic primary antioxidant, 0.2-0.4 parts by weight of a phosphite secondary antioxidant, and 0.4-0.8 parts by weight of a UV stabilizer.

[0063] In some embodiments, in the polypropylene composition, the mass content of the polypropylene resin is not less than 55%.

[0064] The present application also provides a method for preparing the polypropylene composition containing plant fibers, comprising the following steps: mixing polypropylene and a compatibilizer to obtain a first premix; mixing plant fibers and / or surfactant-modified plant fibers, phenolic acid compounds, and additives to obtain a second premix; and uniformly mixing the first premix and the second premix, melt blending, and extrusion granulation to obtain the polypropylene composition.

[0065] In some embodiments, the extrusion temperature is 200-240° C. In some embodiments, the base temperature is set as follows: the temperature of the first stage is 200-210° C.; the temperature of the second to fourth stages is 230-240° C.; the temperature of the fifth to eighth stages is 215-225° C.; and the temperature of the ninth stage is 230-240° C.

[0066] The present application also provides the application of the polypropylene composition containing plant fibers in the field of automobile interior decoration. In some embodiments, the polypropylene composition is used as a seat back panel, door panel, dashboard trim, and other parts of an automobile.

[0067] It is understandable that the present application also discloses a raw material composition for preparing the polypropylene composition containing plant fibers described in any of the above embodiments.

[0068] To better illustrate the purpose, technical solutions, and advantages of this application, the present application will be further described below through specific examples. Unless otherwise specified, the experimental methods used in the examples and / or comparative examples are conventional methods; the materials and reagents used are all commercially available unless otherwise specified.

[0069] Table 1 below lists the sources and types of raw materials used in the examples and comparative examples of the present application. Unless otherwise specified, all reagents were commercially available.

[0070] Table 1 - Sources and types of raw materials in Examples and Comparative Examples

[0071] Examples 1-14 and Comparative Examples 1-3

[0072] A polypropylene composition comprises polypropylene, plant fiber, a phenolic acid compound, a compatibilizer, and other additives. The contents of the components are shown in Tables 2 and 3. The preparation method comprises the following steps:

[0073] (1) mixing polypropylene and a compatibilizer to obtain a first premix;

[0074] (2) combining plant fiber, phenolic acid compound, and additive to obtain a second premix;

[0075] (3) The first premix and the second premix are then uniformly mixed and added to a twin-screw extruder, and subjected to melt blending and extrusion granulation. The extrusion temperature of the twin-screw extruder is 200°C to 240°C, the temperature of the first section is 200°C, the temperature of the 2nd to 4th sections is 240°C, the temperature of the 5th to 8th sections is 220°C, and the temperature of the 9th section of the die head is 240°C to obtain the polypropylene composition.

[0076] Table 2 - Content of each component in Examples 1-12

[0077] Table 3 Content of each component in Examples 13-14 and Comparative Examples 1-3

[0078] Example 15

[0079] A polypropylene composition, wherein the steps, reagents used in the steps, and process parameters of the preparation method are the same as those in Example 1, except that the plant fiber is subjected to an active pretreatment, and the active pretreatment specifically includes the following steps:

[0080] (1) Immersing the plant fiber in a 5% by weight sodium hexametaphosphate aqueous solution at a mass ratio of 1:20 to clean and remove impurities for 15 minutes, then washing with water, and drying at 100°C;

[0081] (2) The dried plant fibers were added to an aqueous solution of a fatty alcohol polyoxyethylene ether AEO-9 surfactant at a mass ratio of 1:20, and the solution was placed in a water bath at 80°C for 10 minutes to allow the surfactant to be fully adsorbed on the surface of the plant fibers, thereby obtaining surfactant-modified plant fibers, wherein the mass of the surfactant used accounted for 1.5% of the mass of the plant fibers.

[0082] Example 16

[0083] A polypropylene composition, wherein the steps, reagents used in the steps, and process parameters of the preparation method are the same as those in Example 15, except that the surfactant is alkyl alcohol polyoxyethylene (1-4) ether ammonium sulfate DNS-360.

[0084] Example 17

[0085] A polypropylene composition, wherein each step, reagents used in each step, and process parameters in its preparation method are the same as those in Example 15, except that the surfactant is sodium polyacrylamide carboxylate 5040.

[0086] Example 18

[0087] A polypropylene composition, wherein the process parameters of each step in the preparation method are the same as those in Example 16, except that the reagents used in each step are the same as those in Example 9.

[0088] Performance testing

[0089] 1. Tensile strength: tested in accordance with ISO 527-2-2016, with a tensile speed of 50 mm / min;

[0090] 2. Simple supported beam notched impact strength: tested in accordance with ISO179-2010 standard, specimen size is 80×10×4mm, A-notch;

[0091] 3. Water absorption: according to ISO 62-2008 Plastics - Determination of water absorption;

[0092] 4. The material performance test items and methods after secondary processing are the same as above.

[0093] Among them, the secondary processing process is: after the polypropylene composition is injection-molded into a seat back panel, it is crushed again and put into a twin-screw extruder for melt blending and secondary extrusion granulation. The parameters are the same as those of the first processing.

[0094] The test results are shown in Table 4

[0095] Table 4 - Performance test results of Examples 1-18 and Comparative Examples 1-3

[0096] As shown in Table 4, the tensile strength of the polypropylene composite prepared in this application is 42-48 MPa, and the Izod notched impact strength is 13.5-18 (KJ / m 2 ), the water absorption rate is 0.7-1.1%. After secondary processing, the tensile strength of the polypropylene combination is still maintained at 42-48MPa, and the cantilever beam notched impact strength is still maintained at 13.5-18 (KJ / m 2 ), the water absorption rate remains at 0.7-1.1%.

[0097] Combining the performance test results of Example 1 and Comparative Examples 1 and 3 in Table 4, it can be seen that the present application uses an appropriate amount of phenolic acid compounds as special linkers to form stable chemical bonds in the material, enhance the molecular structure and stability of the material, and reduce the performance degradation and water absorption increase of the material after secondary processing. However, if the phenolic acid compound is too little (for example, in Comparative Example 1, the amount of plant fiber is too much, resulting in a relatively small amount of phenolic acid compound), its effect is not significant and basically has no effect in the composition. If the phenolic acid compound is too much, it is a polyhydroxy substance and will absorb water, resulting in an increase in water absorption.

[0098] Comparing the data from Examples 1 and 6 shows that phenolic acid compounds can improve the performance and stability of the composition, further optimizing the mechanical properties and water absorption of the polypropylene composition. 2,5-Dihydroxybenzoic acid also enhances the bonding between polypropylene and plant fibers at high temperatures, thereby improving the performance and stability of the composition and further optimizing the mechanical properties and water absorption of the polypropylene composition.

[0099] From the comparison of the data of Examples 1-3 and 7-9, it can be seen that when the plant fibers are flax fibers and bamboo fibers, the mechanical properties and water absorption properties of the polypropylene composition can be further regulated, and the preferred weight ratio of flax fibers to bamboo fibers is 1:(1-2).

[0100] As shown in Examples 15-18, active pretreatment of plant fibers exhibits improved mechanical properties and lower water absorption after secondary processing, representing a superior optimization solution. In addition to the fatty alcohol polyoxyethylene ethers described in the examples, surfactants such as fatty alcohol polyether sulfates and polycarboxylates also meet the pretreatment requirements and achieve similar technical effects.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A polypropylene composition containing plant fibers, characterized in that: The raw materials for preparing the method include the following components in parts by weight: 60-75 parts of polypropylene, 10-35 parts of plant fiber, 1-5 parts of a compatibilizer, 1-4 parts of a phenolic acid compound and 0-5 parts of an auxiliary agent.

2. The polypropylene composition containing plant fibers according to claim 1, characterized in that The plant fiber includes surfactant-modified plant fiber and / or unmodified plant fiber; the plant fiber includes at least one of bamboo fiber, flax fiber, pine fiber, palm fiber, cotton stalk fiber, wheat straw fiber, rice straw fiber and reed stalk fiber.

3. The polypropylene composition containing plant fibers according to claim 2, characterized in that: The plant fibers include flax fibers and bamboo fibers, and the mass ratio of the flax fibers to the bamboo fibers is 1:(0.5-4).

4. The polypropylene composition containing plant fibers according to claim 1, characterized in that The surfactant in the surfactant-modified plant fiber includes at least one of fatty alcohol polyoxyethylene ether, fatty alcohol polyether sulfate, and polycarboxylate surfactants.

5. The polypropylene composition containing plant fibers according to claim 1, characterized in that: In the surfactant-modified plant fiber, the mass of the surfactant added in the process of using the surfactant to modify the plant fiber accounts for 0.1-4% of the mass of the plant fiber.

6. The polypropylene composition containing plant fibers according to claim 1, characterized in that: The phenolic acid compound includes at least one of 6-hydroxy-2-naphthoic acid, 1-naphthol-2-carboxylic acid, p-hydroxybenzoic acid, 2,5-dihydroxybenzoic acid and cinnamphenolic acid.

7. The polypropylene composition containing plant fibers according to claim 1, characterized in that: The compatibilizer includes maleic anhydride grafted polyolefin.

8. The polypropylene composition containing plant fibers according to claim 1, characterized in that: Include at least one of the following: The melt flow rate of the polypropylene is 2-6 g / 10 min at 230° C. and 2.16 kg, and the test standard is ISO1133-2005; The auxiliary agent comprises 0.2-0.4 parts by weight of a phenolic primary antioxidant, 0.2-0.4 parts by weight of a phosphite secondary antioxidant and 0.4-0.8 parts by weight of an ultraviolet stabilizer.

9. A method for preparing a polypropylene composition containing plant fibers according to any one of claims 1 to 8, characterized in that: The steps include: The polypropylene and the compatibilizer are mixed to obtain a first premix; the plant fiber and / or the surfactant-modified plant fiber, the phenolic acid compound and the auxiliary agent are mixed to obtain a second premix; the first premix and the second premix are mixed evenly, melt-blended and extruded to granulate to obtain the polypropylene composition.

10. Use of the polypropylene composition containing plant fibers according to any one of claims 1 to 8 in the field of automobile interior decoration.

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