Preparation method of automobile high-strength flame-retardant interior trim part

Abstract

The invention discloses an automobile high-strength flame-retardant interior trim part and a preparation method thereof. The method comprises the following steps: (1) preparing flame retardant modified titanium dioxide through a three-step reaction: firstly, modifying the surface of nano titanium dioxide with glycidyl ether oxypropyl trimethoxy silane to form an epoxy group, wherein the mass ratio of the epoxy group to the nano titanium dioxide is (1500-1800): (600-750): 100: (15-20); then reacting with p-hydroxybenzaldehyde in the presence of nitrogen to introduce aldehyde groups according to the mass ratio of (2000-2400): 100: (30-36), and carrying out 75-80 DEG C / 8-9 hours; and finally, reacting with DOPO at 0-5 DEG C to graft a phosphorus flame retardant, wherein the mass ratio of DOPO to phosphorus flame retardant is (900-1050): (105-120): 100. (2) blending 3 to 7 parts of modified titanium dioxide with 100 parts of polypropylene resin, 8 to 15 parts of ethylene propylene diene monomer, 0.2 to 0.6 part of antioxidant and 1.2 to 4 parts of maleic anhydride grafted polypropylene; (3) carrying out melt extrusion granulation at 180-215 DEG C; and (4) injection molding or compression molding. Through the surface functionalization design of the nano flame retardant, the oxygen index is greater than or equal to 28% under the condition of low addition amount, the tensile strength is greater than or equal to 25MPa, the notch impact strength is greater than or equal to 8kJ / m, and the problem that the mechanical property is damaged by the traditional flame retardant is solved.

Description

Technical Field

[0001] This invention belongs to the field of automotive parts, and more specifically, relates to a method for preparing high-strength flame-retardant automotive interior parts. Background Technology

[0002] Automotive interior parts (such as dashboards and door panels) must simultaneously meet the requirements of high strength and high flame retardancy. Currently, the mainstream approach is to add halogenated or phosphorus-based flame retardants to the polypropylene (PP) matrix, but this approach has significant drawbacks: Performance imbalance: Conventional flame retardants (such as decabromodiphenyl ether) need to be added at 15-20 wt% to meet the V-0 flame retardancy rating (oxygen index ≥28%) of GB / T 2408, but high addition amounts lead to material embrittlement, reducing tensile strength to below 20 MPa and impact strength to less than 5 kJ / m²; Nano-dispersion challenges: While nano-scale flame retardants (such as titanium dioxide) are highly efficient, they are prone to agglomeration, and direct addition can create stress concentration points, exacerbating the decline in mechanical properties; Processing heat damage risk: PP matrix processing temperatures typically need to be >220℃, while most phosphorus-nitrogen-based flame retardants (such as DOPO derivatives) have poor thermal stability and are prone to decomposition and failure during high-temperature processing.

[0003] Therefore, there is an urgent need to develop a new method that can achieve efficient loading of flame retardants through nanomaterial surface design, reducing the amount added, while maintaining the strength and toughness of the matrix and adapting to low-temperature processing. This invention constructs a "core-shell" flame-retardant structure by grafting DOPO flame-retardant groups onto the surface of titanium dioxide through a three-step chemical modification. Combined with EPDM toughening and maleic anhydride-grafted PP compatibilizer, a synergistic improvement in flame retardancy and mechanical properties is achieved within a low-temperature processing window of 180-215℃. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing high-strength flame-retardant automotive interior parts to solve the problems of performance imbalance, nano-dispersion and high risk of processing heat damage.

[0005] To address the aforementioned technical problems, this invention discloses a method for preparing high-strength flame-retardant automotive interior parts, comprising the following steps: Preparation of flame-retardant modified titanium dioxide: a. Anhydrous ethanol, deionized water, nano-titanium dioxide, and glycidyl etheroxypropyltrimethoxysilane were mixed and reacted at a mass ratio of 1500-1800:600-750:100:15-20, filtered and dried to obtain epoxy-modified titanium dioxide; b. N,N-dimethylformamide, the epoxy-modified titanium dioxide obtained in step a, and p-hydroxybenzaldehyde were reacted at a mass ratio of 2000-2400:100:30-36 under nitrogen at 75-80℃ for 8-9 h, filtered, washed and dried to obtain aldehyde-modified titanium dioxide; c. Organic solvent, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and the aldehyde-modified titanium dioxide obtained in step b were reacted at 0-5℃ for 2-6 hours in a mass ratio of 900-1050:105-120:100, and then separated and dried to obtain flame retardant modified titanium dioxide. Raw material blending: Take 100 parts by weight of polypropylene resin, 8-15 parts of EPDM rubber, 3-7 parts of flame retardant modified titanium dioxide obtained in step (1), 0.2-0.6 parts of antioxidant, and 1.2-4 parts of maleic anhydride grafted polypropylene, and mix them evenly. Melt granulation: The mixture from step (2) is melt-extruded and granulated at 180-215℃ to obtain a high-strength flame-retardant material; Molding: High-strength flame-retardant materials are injection molded or pressed into automotive interior parts.

[0006] According to one embodiment of the present invention, the glycidyl etheroxypropyltrimethoxysilane mentioned in step (1)a above is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0007] According to one embodiment of the present invention, the organic solvent in step (1)c above is tetrahydrofuran or N,N-dimethylformamide.

[0008] According to one embodiment of the present invention, the antioxidant mentioned in step (2) is selected from at least one of antioxidant 168, antioxidant 1010, and antioxidant 1076.

[0009] According to one embodiment of the present invention, the melt extrusion in step (3) above is performed using a twin-screw extruder with a screw length-to-diameter ratio of 40:1-48:1.

[0010] Compared with the prior art, the present invention can achieve the following technical effects: Of course, any product implementing this invention does not necessarily need to achieve all of the technical effects described above at the same time. Detailed Implementation

[0011] The following will describe the implementation of the present invention in detail with reference to the embodiments, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0012] A method for preparing high-strength flame-retardant automotive interior parts includes the following steps: Preparation of flame-retardant modified titanium dioxide: a. Anhydrous ethanol, deionized water, nano-titanium dioxide, and glycidyl etheroxypropyltrimethoxysilane were mixed and reacted in a mass ratio of 1500-1800:600-750:100:15-20, filtered and dried to obtain epoxy-modified titanium dioxide; b. N,N-dimethylformamide, the epoxy-modified titanium dioxide obtained in step a, and p-hydroxybenzaldehyde were reacted in a mass ratio of 2000-2400:100:30-36 under nitrogen at 75-80℃ for 8-9 h, filtered, washed and dried to obtain aldehyde-modified titanium dioxide; c. Organic solvent, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and the aldehyde-modified titanium dioxide obtained in step b were reacted at 0-5℃ for 2-6 hours in a mass ratio of 900-1050:105-120:100, and then separated and dried to obtain flame retardant modified titanium dioxide. Raw material blending: Take 100 parts by weight of polypropylene resin, 8-15 parts of EPDM rubber, 3-7 parts of flame retardant modified titanium dioxide obtained in step (1), 0.2-0.6 parts of antioxidant, and 1.2-4 parts of maleic anhydride grafted polypropylene, and mix them evenly. Melt granulation: The mixture from step (2) is melt-extruded and granulated at 180-215℃ to obtain a high-strength flame-retardant material; Molding: High-strength flame-retardant materials are injection molded or pressed into automotive interior parts.

[0013] In detail, the glycidyl etheroxypropyltrimethoxysilane mentioned in step (1)a is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0014] Specifically, the organic solvent mentioned in step (1)c is tetrahydrofuran or N,N-dimethylformamide.

[0015] In detail, the antioxidant mentioned in step (2) is selected from at least one of antioxidant 168, antioxidant 1010, and antioxidant 1076.

[0016] In detail, the melt extrusion in step (3) uses a twin-screw extruder with a screw length-to-diameter ratio of 40:1-48:1.

[0017] Therefore, three sets of examples with different proportions were carried out according to the above method. Example 1

[0018] A method for preparing high-strength flame-retardant automotive interior parts includes the following steps: Raw material preparation: Prepare 100 parts by weight of polypropylene resin, 8 parts by weight of EPDM rubber, 3 parts by weight of flame retardant modified titanium dioxide, 0.2 parts by weight of antioxidant, and 1.2 parts by weight of compatibilizer maleic anhydride grafted polypropylene. Antioxidant 168 is selected as the antioxidant.

[0019] Preparation of flame retardant modified titanium dioxide: The raw materials were mixed evenly with anhydrous ethanol, deionized water, nano-titanium dioxide, and glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1500:600:100:15, and the mixture was reacted under suitable reaction conditions. After the reaction was completed, the mixture was filtered to remove impurities, and then the product was dried in a drying device to obtain epoxy-modified titanium dioxide.

[0020] N,N-dimethylformamide, epoxy-modified titanium dioxide, and p-hydroxybenzaldehyde were mixed uniformly under a nitrogen atmosphere at a mass ratio of 2000:100:30. The reaction temperature was controlled at 75℃, and the reaction time was 8 hours. After the reaction was completed, the mixture was filtered and washed with a suitable solvent to remove unreacted substances. The mixture was then dried to obtain aldehyde-modified titanium dioxide.

[0021] Tetrahydrofuran was selected as the organic solvent. The organic solvent, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and aldehyde-modified titanium dioxide were mixed thoroughly at a mass ratio of 900:105:100. The reaction temperature was controlled at 0℃, and the reaction time was 2 hours. After the reaction was completed, appropriate separation methods were used to separate the components, followed by drying to obtain flame-retardant modified titanium dioxide.

[0022] Mixing and Processing: Polypropylene resin, EPDM rubber, flame retardant-modified titanium dioxide, antioxidant, and compatibilizer maleic anhydride-grafted polypropylene are placed in a mixing device and thoroughly mixed. Subsequently, the mixed raw materials are melt-extruded at 180°C, granulated, and cooled to obtain a high-strength flame-retardant material for manufacturing automotive interior parts. This high-strength flame-retardant material is then injection molded into automotive interior parts. Example 2

[0023] A method for preparing high-strength flame-retardant automotive interior parts includes the following steps: Raw material preparation: Prepare 100 parts by weight of polypropylene resin, 11 parts by weight of EPDM rubber, 5 parts by weight of flame retardant modified titanium dioxide, 0.4 parts by weight of antioxidant, and 2.6 parts by weight of compatibilizer maleic anhydride grafted polypropylene. Antioxidant 1010 is selected.

[0024] Preparation of flame retardant modified titanium dioxide: The raw materials were mixed thoroughly and reacted according to the mass ratio of anhydrous ethanol, deionized water, nano-titanium dioxide, and glycidyl etheroxypropyltrimethoxysilane of 1650:675:100:17. After the reaction was completed, the mixture was filtered and dried to obtain epoxy-modified titanium dioxide.

[0025] N,N-dimethylformamide, epoxy-modified titanium dioxide, and p-hydroxybenzaldehyde were mixed uniformly under a nitrogen atmosphere at a mass ratio of 2200:100:33. The reaction temperature was controlled at 77℃, and the reaction time was 8.5 h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain aldehyde-modified titanium dioxide.

[0026] N,N-dimethylformamide was selected as the organic solvent. The organic solvent, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and aldehyde-modified titanium dioxide were mixed in a mass ratio of 975:112:100 and reacted at 3°C ​​for 4 hours. After the reaction was completed, the mixture was separated and dried to obtain flame-retardant modified titanium dioxide.

[0027] Mixing and processing: After the raw materials are mixed evenly, they are melt-extruded, granulated and cooled at 195°C to obtain high-strength flame-retardant materials, which are then molded into automotive interior parts through molding process. Example 3

[0028] A method for preparing high-strength flame-retardant automotive interior parts includes the following steps: Raw material preparation: Prepare 100 parts by weight of polypropylene resin, 15 parts by weight of EPDM rubber, 7 parts by weight of flame retardant modified titanium dioxide, 0.6 parts by weight of antioxidant, and 4 parts by weight of compatibilizer maleic anhydride grafted polypropylene. Antioxidant 1076 is selected.

[0029] Preparation of flame retardant modified titanium dioxide: Anhydrous ethanol, deionized water, nano-titanium dioxide, and glycidyl etheroxypropyltrimethoxysilane were mixed in a mass ratio of 1800:750:100:20, reacted thoroughly, filtered, and dried to obtain epoxy-modified titanium dioxide.

[0030] N,N-dimethylformamide, epoxy-modified titanium dioxide, and p-hydroxybenzaldehyde were mixed uniformly under a nitrogen atmosphere at a mass ratio of 2400:100:36. The reaction temperature was controlled at 80℃, and the reaction time was 9 hours. After the reaction was completed, the mixture was filtered, washed, and dried to obtain aldehyde-modified titanium dioxide.

[0031] A mixed solvent of tetrahydrofuran and N,N-dimethylformamide was selected as the organic solvent. The organic solvent, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and aldehyde-modified titanium dioxide were mixed in a mass ratio of 1050:120:100 and reacted at 5°C for 6 hours. After the reaction was completed, the mixture was separated and dried to obtain flame-retardant modified titanium dioxide.

[0032] Mixing and processing: After the raw materials are mixed evenly, they are melt-extruded, granulated and cooled at 215℃ to obtain high-strength flame-retardant materials. Then, according to the needs, injection molding or compression molding processes are selected to make automotive interior parts.

[0033] In the above embodiments, during the preparation of flame-retardant modified titanium dioxide, the reaction conditions at each step, such as temperature, time, and raw material ratio, are strictly controlled to ensure optimal modification results. During the mixing and processing stage, the melt extrusion temperature needs to be precisely controlled according to the characteristics of the raw materials to ensure sufficient melting and mixing, thereby improving the strength and flame-retardant properties of the finished automotive interior parts. In summary, the automotive interior parts prepared in Example 2 possess high strength and excellent flame-retardant properties, meeting the stringent requirements for safety and service life in automotive interior parts. Furthermore, the preparation method is simple, easy to operate, and suitable for large-scale industrial production.

[0034] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for preparing high-strength flame-retardant automotive interior parts, characterized in that, Includes the following steps: (1) Preparation of flame retardant modified titanium dioxide: a. Anhydrous ethanol, deionized water, nano titanium dioxide, and glycidyl etheroxypropyltrimethoxysilane are mixed and reacted in a mass ratio of 1500-1800:600-750:100:15-20, filtered and dried to obtain epoxy-modified titanium dioxide. b. N,N-dimethylformamide, epoxy-modified titanium dioxide obtained in step a, and p-hydroxybenzaldehyde are reacted at 75-80℃ under nitrogen atmosphere for 8-9 hours in a mass ratio of 2000-2400:100:30-36. The mixture is then filtered, washed, and dried to obtain aldehyde-modified titanium dioxide. c. The organic solvent, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and the aldehyde-modified titanium dioxide obtained in step b are reacted at 0-5℃ for 2-6 hours in a mass ratio of 900-1050:105-120:100, and then separated and dried to obtain flame retardant modified titanium dioxide. (2) Raw material blending: Take 100 parts by weight of polypropylene resin, 8-15 parts of EPDM rubber, 3-7 parts of flame retardant modified titanium dioxide obtained in step (1), 0.2-0.6 parts of antioxidant, and 1.2-4 parts of maleic anhydride grafted polypropylene, and mix them evenly. (3) Melt granulation: The mixture from step (2) is melt-extruded and granulated at 180-215℃ to obtain a high-strength flame-retardant material; (4) Molding: High-strength flame-retardant materials are injection molded or molded into automotive interior parts.

2. The method for preparing high-strength flame-retardant automotive interior parts according to claim 1, characterized in that: The glycidyl etheroxypropyltrimethoxysilane mentioned in step (1)a is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

3. The method for preparing high-strength flame-retardant automotive interior parts according to claim 1, characterized in that: The organic solvent mentioned in step (1)c is tetrahydrofuran or N,N-dimethylformamide.

4. The method for preparing high-strength flame-retardant automotive interior parts according to claim 1, characterized in that: The antioxidant mentioned in step (2) is selected from at least one of antioxidant 168, antioxidant 1010, and antioxidant 1076.

5. The method for preparing high-strength flame-retardant automotive interior parts according to claim 1, characterized in that: In step (3), a twin-screw extruder is used for melt extrusion with a screw length-to-diameter ratio of 40:1-48:

1.

6. The method for preparing high-strength flame-retardant automotive interior parts according to any one of claims 1-5, characterized in that: Prepared by the method described in any one of claims 1-5, the oxygen index is ≥28%, the tensile strength is ≥25MPa, and the notched impact strength is ≥8kJ / m².