Modified polypropylene material for automobile interior and preparation method thereof

Abstract

The present invention belongs to the field of polypropylene materials, and in particular to a kind of modified polypropylene material for automobile interior and preparation method thereof. Specifically, the modified polypropylene material for automobile interior includes the following raw materials according to parts by weight: 50-70 parts of polypropylene, 10-20 parts of modified natural rubber, 15-25 parts of amino-modified talcum powder, 0.5-1 part of cross-linking agent, 0.2-1.0 parts of antioxidant, 0.2-0.5 parts of light stabilizer, and 0.1-0.5 parts of processing aid. The present invention modifies natural rubber by adopting specific preparation method and specific stoichiometric ratio, introduces epoxy group and diene body on natural rubber, realizes the crosslinking of natural rubber and polypropylene and the coupling with amino-modified talcum powder at the same time, thereby significantly improving and balancing the rigidity and toughness of polypropylene material, making it more suitable for use as automobile interior material.

Description

Technical Field

[0001] The invention belongs to the field of polypropylene materials, and in particular relates to a modified polypropylene material for automobile interior decoration and a preparation method thereof. Background Art

[0002] Polypropylene is one of the five major general-purpose plastics. Compared to other general-purpose plastics, it offers superior overall performance and has gradually replaced engineering plastics such as ABS and PC / ABS in widespread use in automotive interior components. However, polypropylene generally suffers from poor toughness, failing to meet the impact resistance requirements of automotive interiors. Polypropylene is typically toughened with rubber or elastomers. These materials possess high elasticity and excellent low-temperature properties, and blending them with polypropylene can improve its impact strength and low-temperature brittleness. However, while the use of rubber or elastomers significantly improves material toughness, it also reduces the tensile strength and rigidity of the blend. To overcome this drawback, inorganic rigid particles are often added to compensate for the reduced rigidity caused by the rubber or elastomer toughening. However, inorganic rigid particles have poor compatibility with polypropylene, resulting in poor blending with polypropylene. Existing technologies typically address this issue by using relatively large amounts of polar monomer-grafted polymer compatibilizers. However, these compatibilizers often have a distinct sour odor, making them difficult to meet the low-odor requirements of automotive interior materials. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a modified polypropylene material for automotive interior decoration, which comprises the following raw materials in parts by weight: 50-70 parts of polypropylene, 10-20 parts of modified natural rubber, 15-25 parts of amino-modified talc, 0.5-1 part of cross-linking agent, 0.2-1.0 part of antioxidant, 0.2-0.5 part of light stabilizer, and 0.1-0.5 part of processing aid.

[0004] Furthermore, the modified polypropylene material for automobile interior includes the following raw materials in parts by weight: 65 parts of polypropylene, 15 parts of modified natural rubber, 20 parts of amino-modified talc, 0.5 parts of cross-linking agent, 0.5 parts of antioxidant, 0.3 parts of light stabilizer, and 0.2 parts of processing aid.

[0005] Furthermore, the polypropylene is copolymerized polypropylene, and the melt index is 20 g / 10 min-60 g / 10 min at 230° C. and 2.16 kgf, and the test method is GB / T 3682-2000.

[0006] Furthermore, the modified natural rubber is prepared as follows:

[0007] The natural rubber is reacted with hydrogen peroxide in the presence of formic acid to obtain epoxidized natural rubber, wherein the epoxidation degree of the epoxidized natural rubber is 45%.

[0008] The epoxidized natural rubber is dispersed in an organic solvent, 2-furylmethylamine is added, and the reaction is carried out at 50-100° C. for 3-24 hours under nitrogen protection. The organic solvent is removed by rotary evaporation to obtain a modified natural rubber, wherein the mass ratio of the epoxidized natural rubber to the 2-furylmethylamine is 3:1.

[0009] Furthermore, the reaction is carried out at 30°C-70°C.

[0010] Furthermore, the organic solvent is selected from one or more of chloroform, dichloromethane, toluene, acetone and tetrahydrofuran.

[0011] Furthermore, the natural rubber is natural latex.

[0012] Furthermore, the amino-modified talc is prepared as follows: talc, an aminosilane coupling agent and glacial acetic acid are mixed in a solvent at 60-70° C. for 4-12 hours, filtered and dried to obtain the amino-modified talc.

[0013] Furthermore, the aminosilane coupling agent is selected from 3-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane or N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0014] Furthermore, the solvent is selected from one or more of acetone, ethanol or toluene.

[0015] Furthermore, the cross-linking agent is any one of dicumyl peroxide and dibenzoyl peroxide.

[0016] Furthermore, an example of the antioxidant may be at least one of hindered phenols and phosphite antioxidants; specifically, the antioxidant is at least one of antioxidants 168, 264, 1010, 1076, and 1098; more specifically, the antioxidant is a compound antioxidant composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0017] Furthermore, examples of the light stabilizer may include hindered amine light stabilizers, such as light stabilizer 622, chemical name: polymer of succinic acid and (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol); light stabilizer 770, chemical name: bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate.

[0018] Furthermore, the processing aid is stearate.

[0019] The present invention also provides a method for preparing the modified polypropylene material for automotive interior decoration as described in any one of the above, comprising the following steps:

[0020] (1) Dispersing modified natural rubber and amino-modified talc in dimethylformamide, keeping the temperature at 50-100°C for 10-48 hours, and vacuum drying to obtain a composite component.

[0021] (2) The composite components of step (1) are mixed with a cross-linking agent, stirred for 5-10 minutes, and then polypropylene, an antioxidant, a light stabilizer and a processing aid are added. After mixing evenly, the mixture is kneaded at 180-190° C. for 20-25 minutes, and then extruded, granulated and dried to obtain the modified polypropylene material for automotive interior.

[0022] Beneficial effects of the present invention

[0023] The present invention utilizes the compatibility of natural rubber in a polypropylene matrix that is superior to that of talc, and improves the compatibility of talc with polypropylene through the reaction between epoxidized natural rubber and amino-modified talc. At the same time, the present invention also introduces a diene into the epoxidized natural rubber, allowing it to cross-link with polypropylene through a crosslinking agent, thereby improving the compatibility of natural rubber with polypropylene, and further improving the compatibility of talc with polypropylene. The present invention modifies natural rubber by adopting a specific preparation method and a specific stoichiometric ratio, introducing epoxy groups and diene into the natural rubber, and simultaneously achieving crosslinking of natural rubber with polypropylene and coupling with talc, thereby significantly improving and balancing the rigidity and toughness of the polypropylene material, making it more suitable for use as an automotive interior material. DETAILED DESCRIPTION

[0024] The present invention is further described below with reference to specific examples, which, however, are not intended to limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0025] Example 1

[0026] This embodiment provides a method for preparing modified natural rubber, comprising:

[0027] 60g of natural rubber latex was added to a three-necked flask with mechanical stirring, along with 150ml of distilled water and 2g of Triton. The mixture was stirred for 1 hour to form a stable emulsion. 10ml of formic acid and 50ml of hydrogen peroxide solution were then slowly added dropwise, followed by reaction at 50°C for 10 hours. Finally, after precipitation, washing, and drying, epoxidized natural rubber with an epoxidation degree of 45% was obtained. The epoxidation degree was calculated based on the NMR integral using the following formula:

[0028]

[0029] 30 g of the prepared epoxidized natural rubber was dispersed in 80 mL of tetrahydrofuran, 10 g of 2-furylamine was added, and the mixture was reacted at 65° C. for 24 h under nitrogen protection. The tetrahydrofuran was removed by rotary evaporation to obtain modified natural rubber.

[0030] Example 2

[0031] This embodiment provides a method for preparing amino-modified talc, comprising:

[0032] 50 g of talc, 10 g of γ-aminopropyltriethoxysilane and 50 g of glacial acetic acid were mixed in anhydrous ethanol at 65° C. for 10 h, filtered and dried to obtain amino-modified talc.

[0033] Example 3

[0034] This embodiment provides a modified polypropylene material for automotive interior decoration and a preparation method thereof. The modified polypropylene material includes the following raw materials, in parts by weight: 65 parts of polypropylene (copolymer polypropylene PP M2600R, Shanghai Petrochemical, with a melt index of 30 g / 10 min under the test conditions of GB / T 3682-2000, 230°C, 2.16 kgf), 15 parts of modified natural rubber, 20 parts of amino-modified talc, 0.5 parts of dicumyl peroxide, 0.5 parts of an antioxidant (a composite antioxidant composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1), 0.3 parts of a light stabilizer 622, and 0.2 parts of zinc stearate.

[0035] Its preparation method is:

[0036] (1) Modified natural rubber and amino-modified talc were dispersed in dimethylformamide, kept at 65°C for 12 hours, and vacuum-dried to obtain a composite component.

[0037] (2) The composite components of step (1) are mixed with dicumyl peroxide, stirred for 10 minutes, and then polypropylene, antioxidant, light stabilizer 622 and zinc stearate are added. After mixing evenly, the mixture is kneaded at 185° C. for 20 minutes, and then extruded, granulated and dried to obtain the modified polypropylene material for automotive interior.

[0038] Example 4

[0039] This embodiment provides a modified polypropylene material for automotive interiors and a preparation method thereof. The modified polypropylene material comprises the following raw materials, in parts by weight: 50 parts of polypropylene, 10 parts of modified natural rubber, 15 parts of amino-modified talc, 0.5 parts of dicumyl peroxide, 0.5 parts of an antioxidant (a composite antioxidant composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1), 0.3 parts of a light stabilizer 622, and 0.2 parts of zinc stearate.

[0040] Its preparation method is:

[0041] (1) Dispersing modified natural rubber and amino-modified talc in dimethylformamide, keeping the mixture at 80°C for 20 hours, and vacuum drying the mixture to obtain a composite component.

[0042] (2) The composite components of step (1) are mixed with dicumyl peroxide, stirred for 5 minutes, and then polypropylene, antioxidant, light stabilizer 622 and zinc stearate are added. After mixing evenly, the mixture is kneaded at 190° C. for 25 minutes, and then extruded, granulated and dried to obtain the modified polypropylene material for automotive interior.

[0043] Example 5

[0044] This embodiment provides a modified polypropylene material for automotive interior decoration and a preparation method thereof. The modified polypropylene material includes the following raw materials, in parts by weight: 70 parts of polypropylene, 20 parts of modified natural rubber, 25 parts of amino-modified talc, 0.5 parts of dicumyl peroxide, 0.5 parts of antioxidant (a composite antioxidant composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1), 0.3 parts of light stabilizer 622, and 0.2 parts of zinc stearate.

[0045] Its preparation method is:

[0046] (1) Modified natural rubber and amino-modified talc were dispersed in dimethylformamide, kept at 55°C for 124 hours, and vacuum-dried to obtain a composite component.

[0047] (2) The composite components of step (1) are mixed with dicumyl peroxide, stirred for 10 minutes, and then polypropylene, antioxidant, light stabilizer 622 and zinc stearate are added. After mixing evenly, the mixture is kneaded at 180° C. for 22 minutes, and then extruded, granulated and dried to obtain the modified polypropylene material for automotive interior.

[0048] Comparative Example 1

[0049] This comparative example provides a modified polypropylene material for automotive interior and a preparation method thereof. The modified polypropylene material includes the following raw materials in parts by weight: compared with Example 3, the amount of modified natural rubber added is increased to 25 parts by weight, and the other parts are the same.

[0050] Comparative Example 2

[0051] This comparative example provides a modified polypropylene material for automotive interior and a preparation method thereof. The modified polypropylene material comprises raw materials in parts by weight, compared with Example 3, except that the amount of amino-modified talc added is increased to 30 parts by weight, and other aspects are the same.

[0052] Comparative Example 3

[0053] This comparative example provides a modified polypropylene material for automobile interior and a preparation method thereof. Compared with Example 3, the modified natural rubber used in the preparation process is obtained by reacting 30g of epoxidized natural rubber with 20g of 2-furylamine.

[0054] Comparative Example 4

[0055] This comparative example provides a modified polypropylene material for automobile interior and a preparation method thereof. Compared with Example 3, the modified natural rubber used in the preparation process is obtained by reacting 40g of epoxidized natural rubber with 10g of 2-furylamine.

[0056] Comparative Example 5

[0057] This comparative example provides a modified polypropylene material for automobile interior decoration and a preparation method thereof. Compared with Example 3, unmodified natural rubber is used.

[0058] Comparative Example 6

[0059] This comparative example provides a modified polypropylene material for automobile interior and a preparation method thereof. Compared with Example 3, epoxidized natural rubber is used.

[0060] Comparative Example 7

[0061] This comparative example provides a modified polypropylene material for automobile interior decoration and a preparation method thereof. Compared with Example 3, unmodified talcum powder is used.

[0062] Comparative Example 8

[0063] This comparative example provides a modified polypropylene material for automobile interior decoration and a preparation method thereof. Compared with Example 3, no cross-linking agent is used.

[0064] Performance testing:

[0065] The modified polypropylene materials for automotive interiors prepared in Examples 3-5 and Comparative Examples 1-8 were subjected to the following performance tests. The test results are shown in Table 1:

[0066] Tensile strength: tested according to GB / T 1040-2006 standard, tensile rate is 50mm / min;

[0067] Flexural strength and flexural modulus: tested according to GB / T 9341-2008 standard, with a test speed of 2mm / min;

[0068] Impact strength: tested according to GB / T 1843-2008 standard, the test temperature is 23℃.

[0069] Table 1

[0070]

[0071]

[0072] From the results in Table 1, it can be seen that when the amount of modified natural rubber used exceeds the range specified in the present invention (Comparative Example 1), although the notched impact strength increases, the rigidity of the material decreases significantly; when the amount of amino-modified talc used exceeds the range specified in the present invention (Comparative Example 2), the rigidity of the material does not increase, but decreases. This shows that when the amount of talc is too much, its dispersibility cannot be guaranteed, thereby affecting the reinforcing effect on the material.

[0073] When the mass ratio of epoxidized natural rubber and 2-furylamine used in the preparation process of modified natural rubber is adjusted to 3:2 (Comparative Example 3), the rigidity of the material decreases significantly, while the toughness changes little, indicating that when there are fewer or even no epoxy groups on the modified natural rubber, the modified natural rubber and amino-modified talc cannot work synergistically to promote the dispersion of talc in the polypropylene matrix, resulting in a weakening of the reinforcing effect of talc on the polypropylene material; when the mass ratio of epoxidized natural rubber and 2-furylamine used in the preparation process of modified natural rubber is adjusted to 4:1 (Comparative Example 4), the rigidity and toughness of the material decrease simultaneously, indicating that when there are fewer dienes grafted on the modified natural rubber, it will affect the dispersion of the modified natural rubber in the polypropylene matrix, thereby affecting the toughening of the natural rubber to the polypropylene, and also affecting the reinforcing effect of talc on the polypropylene.

[0074] When unmodified natural rubber and epoxidized natural rubber that has not reacted with 2-furylamine are used (Comparative Examples 5 and 6), the rigidity and toughness of the material are reduced because the natural rubber cannot cooperate with talc and the dispersion of natural rubber in polypropylene cannot be improved.

[0075] When unmodified talc is used (Comparative Example 7), the unmodified talc cannot cooperate with natural rubber, resulting in poor dispersion of talc in the polypropylene matrix, which weakens the reinforcing effect of talc on the polypropylene material and has little effect on the toughness of the material.

[0076] When no crosslinking agent is used (Comparative Example 8), the dispersion of natural rubber in the polypropylene matrix is not improved, resulting in a weakened toughening effect on the material. It also affects the dispersion of talc powder, causing a slight decrease in the rigidity of the material.

[0077] It should be noted that the description of the present invention provides preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this description. These embodiments are not intended to be additional limitations on the content of the present invention. The purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present invention. In addition, the above-mentioned technical features can be combined with each other to form various embodiments not listed above, which are all considered to be within the scope of the description of the present invention. Furthermore, it is obvious to those skilled in the art that improvements or changes can be made based on the above description, and all such improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A modified polypropylene material for automobile interior, characterized in that: The following raw materials are included in parts by weight: 50-70 parts of polypropylene, 10-20 parts of modified natural rubber, 15-25 parts of amino-modified talc, 0.5-1 parts of crosslinking agent, 0.2-1.0 parts of antioxidant, 0.2-0.5 parts of light stabilizer, and 0.1-0.5 parts of processing aid; The modified natural rubber is prepared as follows: natural rubber is reacted with hydrogen peroxide in the presence of formic acid to obtain epoxidized natural rubber, wherein the epoxidized natural rubber has an epoxidation degree of 45%; the epoxidized natural rubber is dispersed in an organic solvent, 2-furylmethylamine is added, and the mixture is reacted at 50-100° C. for 3-24 hours under nitrogen protection, and the organic solvent is removed by rotary evaporation to obtain the modified natural rubber, wherein the mass ratio of the epoxidized natural rubber to the 2-furylmethylamine is 3:1; The amino-modified talc is prepared as follows: talc, aminosilane coupling agent and glacial acetic acid are mixed in a solvent at 60-70° C. for 4-12 hours, filtered and dried to obtain amino-modified talc; The cross-linking agent is any one of dicumyl peroxide and dibenzoyl peroxide.

2. The modified polypropylene material according to claim 1, characterized in that The following raw materials are included in parts by weight: 65 parts of polypropylene, 15 parts of modified natural rubber, 20 parts of amino-modified talc, 0.5 parts of a cross-linking agent, 0.5 parts of an antioxidant, 0.3 parts of a light stabilizer, and 0.2 parts of a processing aid.

3. The modified polypropylene material according to claim 1, characterized in that The polypropylene is copolymerized polypropylene, and its melt index is 20 g / 10 min to 60 g / 10 min at 230° C. and 2.16 kgf.

4. The modified polypropylene material according to claim 1, characterized in that The organic solvent is selected from one or more of chloroform, dichloromethane, toluene, acetone and tetrahydrofuran.

5. The modified polypropylene material according to claim 1, characterized in that: The solvent is selected from one or more of acetone, ethanol or toluene.

6. The modified polypropylene material according to claim 1, characterized in that: The processing aid is stearate.

7. A method for preparing a modified polypropylene material for automotive interior according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Dispersing modified natural rubber and amino-modified talc in dimethylformamide, keeping the temperature at 50-100°C for 10-48 hours, and vacuum drying to obtain a composite component. (2) The composite components of step (1) are mixed with a cross-linking agent, stirred for 5-10 minutes, and then polypropylene, an antioxidant, a light stabilizer and a processing aid are added. After mixing evenly, the mixture is kneaded at 180-190° C. for 20-25 minutes, and then extruded, granulated and dried to obtain the modified polypropylene material for automotive interior.

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