Flame-retardant polypropylene composition for automotive trim and preparation method of flame-retardant polypropylene composition

Abstract

The invention relates to the technical field of flame-retardant polypropylene materials, and discloses a flame-retardant polypropylene composition for automotive interiors and a preparation method thereof.The composition is prepared from, by mass, 30-60 parts of polypropylene hydrocarbon, 10-40 parts of methyl vinyl silicone rubber, 8-12 parts of compatilizer, 1-10 parts of dimethyl silicone oil, 0.01-0.1 part of catalyst, 1-2 parts of hydrogen-containing silicone oil, 0.5-2 parts of dispersing agent, 0.1-0.5 part of antioxidant and 16-21 parts of flame retardant. The flame retardant is formed by mixing a first flame retardant and a second flame retardant according to a mass ratio of 1: (1-2); the first flame retardant is prepared from the following raw materials: melamine, phosphonitrilic chloride trimer, diphenyl disilanol, triethylamine and a solvent; the second flame retardant is at least one of piperazine pyrophosphate, melamine polyphosphate MPP, aluminum diethylphosphinate, aluminum phosphite and ammonium polyphosphate. According to the invention, the problem that flame-retardant polypropylene for automotive interiors in the prior art cannot give consideration to both flame retardance and mechanical properties well is solved.

Description

Technical Field

[0001] The invention relates to the technical field of flame-retardant polypropylene materials, and in particular to a flame-retardant polypropylene composition for automobile interior decoration and a preparation method thereof. Background Art

[0002] Polypropylene (PP), as an important thermoplastic, has been widely used in many industrial fields. Its relatively low cost, good processability, excellent mechanical properties, corrosion resistance and weather resistance make polypropylene one of the ideal materials for automotive interior parts. Polypropylene is often used in automotive dashboards, pillars, door panels and other parts, and can maintain stable performance under harsh environmental conditions. However, polypropylene materials have poor flame retardant properties and are easy to burn at high temperatures, causing fires. In order to solve this problem, flame retardants are usually added to polypropylene for flame retardant modification to improve its flame retardant properties, making it less likely to burn at high temperatures, effectively preventing the spread of flames, and thus reducing the losses caused by fire accidents.

[0003] In the production process of polypropylene materials for automotive interior parts, a large amount of flame retardants are usually added. At present, there are two main types of commonly used flame retardants: halogen flame retardants and halogen-free flame retardants. Halogenated flame retardants, such as bromine-containing and chlorine-containing flame retardants, will release toxic halogen compounds when burned, posing potential risks to the environment and human health. In order to reduce these potential risks, it has become a trend to restrict the use of halogenated flame retardants; halogen-free flame retardants are widely used due to their environmental protection and high efficiency. Among them, phosphorus-containing flame retardants are a more common type of halogen-free flame retardant. However, the phosphorus-containing flame retardants commonly used at present, such as ammonium polyphosphate (APP) and melamine polyphosphate (MPP), require a large amount of addition to obtain ideal flame retardant properties, which can easily cause irreversible damage to the mechanical properties of polypropylene materials and affect the practical application of the product. Therefore, it is urgent to develop a new type of flame-retardant polypropylene for automotive interiors, which can achieve high-efficiency flame retardancy while taking into account the mechanical properties of the material. Summary of the invention

[0004] The present invention aims to provide a flame retardant polypropylene composition for automobile interior and a preparation method thereof, so as to solve the problem that the flame retardant polypropylene for automobile interior in the prior art cannot well balance the flame retardancy and mechanical properties.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a flame-retardant polypropylene composition for automobile interior, which comprises, by weight, 30 to 60 parts of polypropylene, 10 to 40 parts of methyl vinyl silicone rubber, 8 to 12 parts of a compatibilizer, 1 to 10 parts of dimethyl silicone oil, 0.01 to 0.1 parts of a catalyst, 1 to 2 parts of hydrogenated silicone oil, 0.5 to 2 parts of a dispersant, 0.1 to 0.5 parts of an antioxidant, and 16 to 21 parts of a flame retardant, wherein the flame retardant is a mixture of a first flame retardant and a second flame retardant in a mass ratio of 1:1 to 2; the raw materials of the first flame retardant include melamine, hexachlorocyclotriphosphazene, diphenyldisilanol, triethylamine and a solvent; the second flame retardant is at least one of piperazine pyrophosphate, melamine polyphosphate MPP, aluminum diethylphosphinate, aluminum phosphite and ammonium polyphosphate.

[0006] Preferably, as an improvement, the preparation method of the first flame retardant comprises the following steps:

[0007] S1. dissolving melamine in acetonitrile or pyridine, dissolving hexachlorocyclotriphosphazene in acetonitrile or pyridine;

[0008] S2, slowly adding the hexachlorocyclotriphosphazene solution to the melamine solution in an ice bath and ultrasonic state, then adding triethylamine, stirring and reacting to obtain system I;

[0009] S3, dissolving diphenyldisilanol in acetonitrile or pyridine, and pouring into the above system I, stirring at room temperature, and then slowly heating to react, to obtain system II;

[0010] S4. Filter out the precipitate from system II, wash it repeatedly with hot deionized water and ethanol, and vacuum dry it to obtain the final product, the first flame retardant.

[0011] Preferably, as an improvement, the melt index of the polypropylene is 2 to 25 g / 10 min.

[0012] Preferably, as an improvement, the molecular weight of the methyl vinyl silicone rubber is 400,000 to 600,000, and the molar content of vinyl is 0.04 to 0.24%.

[0013] Preferably, as an improvement, the compatibilizer is PP grafted vinyl triethoxysilane, and the grafting rate is 1.0%.

[0014] Preferably, as an improvement, the viscosity of the dimethyl silicone oil is 350-1000 mPa·s.

[0015] Preferably, as an improvement, the catalyst is a Castaplatin catalyst; the hydrogen molar content of the hydrogen-containing silicone oil is 0.5-1.5%; the dispersant is E525; and the antioxidant is antioxidant 168.

[0016] Preferably, as an improvement, a method for preparing a flame retardant polypropylene composition for automobile interior decoration comprises the following steps:

[0017] Step 1, mixing methyl vinyl silicone rubber, dimethyl silicone oil, hydrogen-containing silicone oil and a catalyst, and kneading;

[0018] Step 2, adding flame retardant, polypropylene, compatibilizer and antioxidant, and continuing to mix;

[0019] Step 3: Using a twin-screw extruder to melt extrude and granulate, flame-retardant polypropylene masterbatch for automotive interiors is obtained.

[0020] Preferably, as an improvement, in step one, the banburying temperature is 80-90° C., and the banburying time is 30-50 min; in step two, the banburying time is 3-10 min.

[0021] Preferably, as an improvement, in step three, the temperatures of each extrusion section are: feeding section 130-160°C, melting section: 160-180°C, conveying section: 180-200°C, and die head temperature 190-200°C.

[0022] The principle and advantage of this solution are: in actual application, in this technical solution, the inventor comprehensively optimizes the raw materials, formula and preparation process of the polypropylene composition in view of the problem that the flame-retardant polypropylene used for automobile interior decoration in the prior art cannot well take into account the flame retardancy and mechanical properties. In view of the raw materials, the inventor creatively designed a composite flame retardant, firstly taking the phosphazene flame retardant with relatively high natural effect and low smoke and low toxicity of combustion products as the starting point, and found through research and testing that the flame retardant performance of the single phosphorus-containing flame retardant is poor. Through continuous testing and research, the inventor creatively introduced other flame retardant elements Si / N into the phosphorus-containing flame retardant to achieve synergistic flame retardancy, and formed a ternary integrated flame retardant containing P / N / Si by designing the molecular structure of the first flame retardant, which can make the polypropylene material obtain high-efficiency flame retardancy at a relatively small addition amount. In addition, due to the reduction of the addition amount of the flame retardant, the polypropylene composition prepared by this technical solution also has the advantages of high mechanical properties and has unexpected technical effects. Through experimental verification, it is shown that the flame-retardant polypropylene material obtained by this technical solution has excellent flame retardant properties, reduces the amount of flame retardant added, while maintaining ideal flame retardant properties (UL-94V-0), and the flame retardant has good compatibility with the matrix material, and the mechanical properties are not significantly affected. DETAILED DESCRIPTION

[0023] The following is further described in detail through specific implementations, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the technical means used in the following implementations are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; the materials, reagents, etc. used can all be obtained from commercial channels.

[0024] Program Overview:

[0025] A flame-retardant polypropylene composition for automobile interior decoration comprises, by weight, 30-60 parts of polypropylene, 10-40 parts of methyl vinyl silicone rubber, 8-12 parts of a compatibilizer, 1-10 parts of dimethyl silicone oil, 0.01-0.1 parts of a catalyst, 1-2 parts of hydrogenated silicone oil, 0.5-2 parts of a dispersant, 0.1-0.5 parts of an antioxidant and 16-21 parts of a flame retardant.

[0026] Among them, the melt index of polypropylene is 2 to 25 g / 10 min;

[0027] The molecular weight of methyl vinyl silicone rubber is 400,000-600,000, and the vinyl molar content is 0.04-0.24%;

[0028] The compatibilizer is PP grafted vinyl triethoxysilane, with a grafting rate of 1.0%;

[0029] The viscosity of dimethyl silicone oil is 350-1000 mPa·s;

[0030] The catalyst is a Castaplatin catalyst;

[0031] The hydrogen molar content of hydrogen-containing silicone oil is 0.5-1.5%;

[0032] The dispersant is E525;

[0033] The antioxidant is antioxidant 168;

[0034] The flame retardant is a composite flame retardant, which is formed by mixing a first flame retardant and a second flame retardant in a mass ratio of 1:1 to 2; wherein the second flame retardant is at least one of piperazine pyrophosphate, melamine polyphosphate MPP, aluminum diethylphosphinate, aluminum phosphite, and ammonium polyphosphate; the structural formula of the first flame retardant is shown in formula (I):

[0035]

[0036] The preparation method of the first flame retardant comprises the following steps:

[0037] S1. Dissolve 0.3 mol of melamine (MEA, 126 g / mol) in 400 mL of acetonitrile or pyridine, and dissolve 0.1 mol of hexachlorocyclotriphosphazene (HCCP, 347.6 g / mol) in acetonitrile or pyridine (100 mL);

[0038] S2. In an ice bath and ultrasonic state, slowly add the HCCP solution to the MEA solution, then add 6 ml of triethylamine, and then stir and react for 2 to 12 hours to obtain system I;

[0039] S3, dissolving 0.1 mol of diphenyldisilanol (216.3 g / mol) in 300 mL of acetonitrile or pyridine, and pouring into the above system I, stirring at room temperature for 0.5 to 2 h, then slowly heating to 40 to 80° C., reacting for 4 to 24 h, to obtain system II;

[0040] S4. Filter out the precipitate from system II, wash it repeatedly with hot deionized water and ethanol, and vacuum dry it at 120° C. for 12 hours to obtain the final product, the first flame retardant.

[0041] A method for preparing a flame-retardant polypropylene composition for automobile interior, comprising the following steps:

[0042] Step 1: Mix methyl vinyl silicone rubber, dimethyl silicone oil, hydrogen-containing silicone oil and catalyst, and knead at 80-90° C. for 30-50 minutes;

[0043] Step 2: Add flame retardant, polypropylene, compatibilizer and antioxidant, and continue mixing for 3 to 10 minutes;

[0044] Step 3: Use a twin-screw extruder to melt extrude and granulate. The temperatures of each extrusion section are as follows: feeding section 130-160°C, melting section: 160-180°C, conveying section: 180-200°C, and die head temperature 190-200°C to obtain flame-retardant polypropylene masterbatch for automotive interior.

[0045] Examples 1-4 are examples of the present invention, and Comparative Examples 1-5 are comparative examples of the present invention. The preparation processes and raw material properties of each example and comparative example are basically the same as those in the general description of the above scheme, except that the composition and addition amount of the raw materials are different, as shown in Table 1. Note: " / " means no addition.

[0046] Table 1

[0047]

[0048] Taking Example 1 as an example, a method for preparing a flame-retardant polypropylene composition for automobile interior decoration of the present invention is described in detail, comprising the following steps:

[0049] Step 1: Mix 10 kg of methyl vinyl silicone rubber, 5 kg of dimethyl silicone oil, 1 kg of hydrogen-containing silicone oil and 0.02 kg of Castaplatin catalyst, and knead at 85° C. for 45 minutes;

[0050] Step 2: Add 14 kg of piperazine pyrophosphate, 7 kg of the first flame retardant, 60 kg of polypropylene, 10 kg of a compatibilizer, 1 kg of a dispersant, and 0.3 kg of an antioxidant, and continue mixing for 6 minutes;

[0051] Step 3: Use a twin-screw extruder to melt extrude and granulate. The temperatures of each extrusion section are as follows: feeding section 145°C, melting section: 165°C, conveying section: 190°C, and die head temperature 195°C to obtain flame-retardant polypropylene masterbatch for automotive interior.

[0052] Experimental Example 1 Flame retardant and mechanical properties test

[0053] The flame retardant polypropylene compositions for automotive interior prepared in the above embodiments and comparative examples were tested for flame retardant properties and mechanical properties. The flame retardant properties and mechanical properties were tested as follows:

[0054] The flame retardant performance test method is carried out in accordance with GB / T 2408-2008 and ASTM D2863;

[0055] The mechanical properties testing method is carried out with reference to GB / T 1040.1-2018 and GB / T 1843-2008.

[0056] The experiment was repeated three times for each group, and the test results are shown in Table 2: The results show that the flame retardancy and mechanical properties of the flame retardant polypropylene compositions prepared in each embodiment of the present invention are significantly higher than those of the comparative examples, and the composite flame retardant using the present technical solution has outstanding advantages over the use of the first flame retardant or piperazine pyrophosphate alone. Comparative Examples 1 to 3 use piperazine pyrophosphate in combination with MPP, and their flame retardant effects and mechanical properties are not comparable to those of the present technical solution.

[0057] Table 2

[0058] Group UL-94(1.6mm) Oxygen Index Tensile strength / MPa <![CDATA[Notched impact strength / kJ / m 2 > Example 1 V-0 39.6 19.8 21.8 Example 2 V-1 37.7 22.5 25.7 Example 3 V-0 38.9 21.8 23.7 Example 4 V-0 39.0 20.3 24.6 Comparative Example 1 Not extinguished 36.1 16.0 16.1 Comparative Example 2 V-2 37.0 15.5 16.6 Comparative Example 3 Not extinguished 36.7 15.4 15.7 Comparative Example 4 V-1 37.1 18.8 19.4 Comparative Example 5 Not extinguished 33.2 13.5 10.3

[0059] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A flame retardant polypropylene composition for automobile interior, characterized in that: The invention comprises, by weight, 30 to 60 parts of polypropylene, 10 to 40 parts of methyl vinyl silicone rubber, 8 to 12 parts of a compatibilizer, 1 to 10 parts of dimethyl silicone oil, 0.01 to 0.1 parts of a catalyst, 1 to 2 parts of hydrogenated silicone oil, 0.5 to 2 parts of a dispersant, 0.1 to 0.5 parts of an antioxidant, and 16 to 21 parts of a flame retardant. The flame retardant is prepared by mixing a first flame retardant and a second flame retardant in a weight ratio of 1:1 to 2. The raw materials of the first flame retardant include melamine, hexachlorocyclotriphosphazene, diphenyldisilanol, triethylamine, and a solvent. The second flame retardant is at least one of piperazine pyrophosphate, melamine polyphosphate MPP, aluminum diethylphosphinate, aluminum phosphite, and ammonium polyphosphate.

2. The flame-retardant polypropylene composition for automotive interior according to claim 1, characterized in that: The preparation method of the first flame retardant comprises the following steps: S1. dissolving melamine in acetonitrile or pyridine, dissolving hexachlorocyclotriphosphazene in acetonitrile or pyridine; S2, slowly adding the hexachlorocyclotriphosphazene solution to the melamine solution in an ice bath and ultrasonic state, then adding triethylamine, stirring and reacting to obtain system I; S3, dissolving diphenyldisilanol in acetonitrile or pyridine, and pouring into the above system I, stirring at room temperature, and then slowly heating to react, to obtain system II; S4. Filter out the precipitate from system II, wash it repeatedly with hot deionized water and ethanol, and vacuum dry it to obtain the final product, the first flame retardant.

3. The flame retardant polypropylene composition for automotive interior according to claim 2, characterized in that: The melt index of the polypropylene is 2 to 25 g / 10 min.

4. The flame retardant polypropylene composition for automotive interior according to claim 3, characterized in that: The molecular weight of the methyl vinyl silicone rubber is 400,000-600,000, and the molar content of vinyl is 0.04-0.24%.

5. The flame retardant polypropylene composition for automotive interior according to claim 4, characterized in that: The compatibilizer is PP grafted vinyl triethoxysilane, and the grafting rate is 1.0%.

6. The flame-retardant polypropylene composition for automotive interior according to claim 5, characterized in that: The viscosity of the dimethyl silicone oil is 350-1000 mPa·s.

7. The flame-retardant polypropylene composition for automotive interior according to claim 6, characterized in that: The catalyst is a Castaplatin catalyst; the hydrogen molar content of the hydrogen-containing silicone oil is 0.5-1.5%; the dispersant is E525; and the antioxidant is antioxidant 168.

8. The method for preparing a flame-retardant polypropylene composition for automobile interior decoration according to any one of claims 1 to 7, characterized in that: The steps include: Step 1, mixing methyl vinyl silicone rubber, dimethyl silicone oil, hydrogen-containing silicone oil and a catalyst, and kneading; Step 2, adding flame retardant, polypropylene, compatibilizer and antioxidant, and continuing to mix; Step 3: Using a twin-screw extruder to melt extrude and granulate, flame-retardant polypropylene masterbatch for automotive interiors is obtained.

9. The method for preparing a flame-retardant polypropylene composition for automobile interior according to claim 8, characterized in that: In step 1, the banburying temperature is 80-90° C. and the banburying time is 30-50 min; in step 2, the banburying time is 3-10 min.

10. The method for preparing a flame-retardant polypropylene composition for automobile interior according to claim 9, characterized in that: In step 3, the temperatures of each extrusion section are: feeding section 130-160°C, melting section: 160-180°C, conveying section: 180-200°C, and die head temperature 190-200°C.

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