A maleic anhydride grafted polypropylene and a method for its preparation

Abstract

The present application relates to the technical field of polypropylene production, and in particular to a maleic anhydride grafted polypropylene and a preparation method thereof. The preparation method of the maleic anhydride grafted polypropylene comprises the following steps: weighing 100-120 parts of polypropylene, 4-5 parts of maleic anhydride, 0.6-0.8 parts of a grafting aid, 0.3-0.4 parts of an initiator and 0.1-0.2 parts of an antioxidant, uniformly mixing them, and then extruding and granulating through a double-screw extruder to obtain the maleic anhydride grafted polypropylene; wherein the grafting aid is compounded from trimethylolpropane trimethacrylate, ethylene-propylene-diene rubber and 4,4-dihydroxydiphenyl sulfide at a mass ratio of 1:(0.7-0.9):(0.8-1). The preparation method can significantly improve the grafting rate of the maleic anhydride grafted polypropylene, and significantly improve the compatibility of the polypropylene and polar materials. The maleic anhydride grafted polypropylene prepared by the present application is a good compatibilizer.

Description

Technical Field

[0001] The present invention relates to the technical field of polypropylene production, in particular to maleic anhydride grafted polypropylene and a preparation method thereof. Background Art

[0002] As an important thermoplastic, polypropylene has excellent properties such as low density, easy processing, heat resistance, and electrical insulation. It is widely used in various fields such as machinery, automobiles, and electronic products. However, with the advancement of science and technology and the development of industry, the functional requirements for polypropylene materials are also increasing. Nowadays, polypropylene is usually modified by blending it with inorganic materials or polar polymers. However, since polypropylene is a non-polar material, it has poor compatibility with polar materials, resulting in a decrease in the mechanical properties and stability of the blended material, limiting its scope of application. Maleic anhydride grafted polypropylene, as a modified polypropylene, has good polarity and reactivity, and can effectively improve the compatibility of polypropylene with inorganic materials and polar polymers, broadening its application areas.

[0003] Maleic anhydride grafted polypropylene is typically prepared using a melt extrusion method. However, conventional maleic anhydride grafted polypropylene suffers from a low grafting rate. This is because a series of side reactions, such as chain scission, degradation, and chain transfer, occur during the melt grafting process, affecting the reaction between maleic anhydride and polypropylene, resulting in a low grafting rate and a large amount of residual maleic anhydride. This significantly reduces the compatibility of the resulting maleic anhydride grafted polypropylene, making it difficult to improve the compatibility of polypropylene with inorganic materials and polar polymers. Therefore, it is necessary to develop a new method for preparing maleic anhydride grafted polypropylene to increase the grafting rate between maleic anhydride and polypropylene, thereby further improving the compatibility of polypropylene with polar materials. Summary of the Invention

[0004] To address the low grafting rate of maleic anhydride-grafted polypropylene in the prior art, the present application provides a maleic anhydride-grafted polypropylene and a preparation method thereof. By introducing a grafting aid composed of trimethylolpropane trimethacrylate, ethylene propylene diene monomer (EPDM), and 4,4-dihydroxydiphenyl sulfide into the preparation method of maleic anhydride-grafted polypropylene, the present application significantly increases the grafting rate of the maleic anhydride-grafted polypropylene, thereby significantly improving the compatibility of polypropylene with polar materials.

[0005] In a first aspect, the present application provides a method for preparing maleic anhydride grafted polypropylene, which adopts the following technical solution:

[0006] A method for preparing maleic anhydride grafted polypropylene, characterized by comprising:

[0007] Step 1: Weigh 100-120 parts of polypropylene, 4-5 parts of maleic anhydride, 0.6-0.8 parts of grafting aid, 0.3-0.4 parts of initiator and 0.1-0.2 parts of antioxidant by mass, and mix them evenly;

[0008] Step 2: Extruding the mixture into pellets through a twin-screw extruder to obtain maleic anhydride grafted polypropylene;

[0009] The grafting auxiliary agent is prepared by compounding trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 1: (0.7-0.9): (0.8-1).

[0010] In the above technical solution, the present application achieves a high grafting rate of maleic anhydride and polypropylene by introducing a grafting aid with a specific ratio. Specifically, trimethylolpropane trimethacrylate can provide multiple active sites to promote the grafting reaction of maleic anhydride and polypropylene, while the addition of ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide further improves the dispersibility of maleic anhydride in polypropylene. The present application combines trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide into a grafting aid in a specific mass ratio, which can give full play to their synergistic effect, significantly increase the collision probability of maleic anhydride and polypropylene macromolecular free radicals, effectively stabilize polypropylene macromolecular free radicals, and inhibit the degradation reaction of polypropylene macromolecular free radicals, thereby significantly improving the grafting rate of maleic anhydride grafted polypropylene.

[0011] Preferably, the initiator is prepared by compounding tert-butyl perbenzoate and dicumyl peroxide in a mass ratio of 1:(0.5-0.7).

[0012] In the above technical solution, the present application introduces a combination of t-butyl perbenzoate and dicumyl peroxide as initiators, allowing for more precise control of the grafting reaction process and further improving the grafting efficiency of maleic anhydride onto polypropylene. T-butyl perbenzoate and dicumyl peroxide, two common organic peroxides, exhibit different reactivity when initiating free radical reactions on the polypropylene molecular chain, ensuring the continued progress of the grafting reaction.

[0013] Preferably, the antioxidant is a compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0014] In the above technical solution, the present application introduces a compound of antioxidant 1010 and antioxidant 168 as an antioxidant, which can effectively inhibit the oxidative degradation of maleic anhydride grafted polypropylene during the preparation and storage process, and maintain the long-term stability and service life of maleic anhydride grafted polypropylene.

[0015] Preferably, the twin-screw extruder has eight sections, and the reaction temperature of each section is as follows:

[0016] Stage 1: 150-170℃, Stage 2: 160-170℃, Stage 3: 170-190℃, Stage 4: 170-190℃, Stage 5: 170-180℃, Stage 6: 160-170℃, Stage 7: 160-170℃, Stage 8: 160-170℃.

[0017] In the above technical solution, the present application provides suitable temperature conditions for the preparation of maleic anhydride grafted polypropylene by precisely controlling the reaction temperature of each section of the twin-screw extruder. This temperature gradient design not only ensures sufficient contact and reaction between maleic anhydride and polypropylene molecular chains, but also further reduces side reactions during the reaction process, thereby ensuring the grafting rate and quality of the maleic anhydride grafted polypropylene.

[0018] Preferably, the main engine screw speed is 180-200r / min.

[0019] In the above technical solution, the present application ensures sufficient mixing and reaction of maleic anhydride grafted polypropylene in the twin-screw extruder by precisely controlling the speed of the main screw. The appropriate speed can accelerate the flow and mixing of the materials in the extruder, improving the uniformity and efficiency of the grafting reaction.

[0020] Preferably, in step 1, 100 parts of polypropylene, 4.2 parts of maleic anhydride, 0.65 parts of grafting aid, 0.3 parts of initiator and 0.1 parts of antioxidant are weighed in parts by mass.

[0021] Preferably, the grafting aid is prepared by compounding trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 1:0.8:0.9.

[0022] In the above technical solution, this application further improves the grafting rate and finished product quality of maleic anhydride-grafted polypropylene by further optimizing the formula. The preferred ratio of polypropylene, maleic anhydride, grafting aid, initiator, and antioxidant can better promote the dispersion of maleic anhydride in polypropylene, increase the probability of grafting between maleic anhydride and polypropylene, and improve the grafting rate of maleic anhydride-grafted polypropylene, thereby obtaining maleic anhydride-grafted polypropylene with improved compatibility with polar materials.

[0023] In a second aspect, the present application also provides a maleic anhydride grafted polypropylene, which adopts the following technical solution:

[0024] A maleic anhydride grafted polypropylene is prepared by the preparation method of the maleic anhydride grafted polypropylene as described in the first aspect.

[0025] In the above technical solution, the maleic anhydride-grafted polypropylene of the present application is prepared using the preparation method described in the first aspect. This maleic anhydride-grafted polypropylene has a high grafting rate and good compatibility with polar materials, and has broad application prospects in fields such as plastic modification, coatings, and adhesives. Furthermore, the maleic anhydride-grafted polypropylene of the present application can also be used as a compatibilizer to improve the compatibility between different polymers, thereby broadening the application range of polymer materials.

[0026] In summary, this application has the following beneficial technical effects:

[0027] 1. This application introduces a grafting aid composed of trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide. The three interact with each other in multiple dimensions, such as providing active sites for grafting reactions, improving the dispersibility of maleic anhydride and stabilizing polypropylene macromolecular free radicals, thereby significantly improving the grafting rate of maleic anhydride grafted polypropylene, thereby significantly improving the compatibility of maleic anhydride grafted polypropylene with polar materials, and significantly improving the compatibilization of maleic anhydride grafted polypropylene.

[0028] 2. This application further optimizes the initiator and antioxidant to further ensure the smooth progress of the grafting reaction of maleic anhydride grafted polypropylene and further improve the grafting rate of maleic anhydride grafted polypropylene.

[0029] 3. This application further optimizes the reaction temperature of each section of the twin-screw extruder and the main screw speed to ensure sufficient contact and reaction between maleic anhydride and polypropylene molecular chains, reduce side reactions during the reaction process, ensure the smooth progress of the reaction of maleic anhydride grafted polypropylene, and ensure the quality of the finished product. DETAILED DESCRIPTION

[0030] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0031] Unless otherwise specified, the raw materials used in the following specific embodiments are all common commercial products and can be purchased from the market.

[0032] Polypropylene: Source: Sinopec, brand EPT30R.

[0033] Maleic anhydride: sourced from Shanghai MacLean Biochemical Technology Co., Ltd., industrial grade, purity ≥99%.

[0034] Trimethylolpropane trimethacrylate: Source: Youming (Shanghai) Chemical Co., Ltd., brand Changxing, grade EM331 TMPTMA.

[0035] EPDM rubber: Source: Guangzhou Degao New Materials Co., Ltd., brand: ENI, grade: TER 4436.

[0036] 4,4-Dihydroxydiphenyl sulfide: Source: Hubei Xingyan New Material Technology Co., Ltd.

[0037] Antioxidant 1010: Originated from Dongguan Xingyuan Chemical Co., Ltd., chemical name: Pentaerythritol Tetrakis[B-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0038] Antioxidant 168: Originated from Dongguan Xingyuan Chemical Co., Ltd., chemical name: tris(2,4-di-tert-butylphenyl) phosphite.

[0039] Twin-screw extruder: Source: Nanjing Rubber and Plastic Machinery Factory Co., Ltd., model is SJSH-30.

[0040] Example 1

[0041] A maleic anhydride grafted polypropylene comprises 100 kg of polypropylene, 4.2 kg of maleic anhydride, 0.65 kg of a grafting aid, 0.3 kg of an initiator and 0.1 kg of an antioxidant.

[0042] The grafting auxiliary agent is prepared by compounding trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 1:0.8:0.9.

[0043] The initiator is a compound of tert-butyl perbenzoate and diisopropylbenzene peroxide in a mass ratio of 1:0.6.

[0044] The antioxidant is prepared by compounding antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0045] Wherein, the preparation method of maleic anhydride grafted polypropylene comprises:

[0046] The raw materials in the above formula amounts were mixed evenly, put into a twin-screw extruder, melted under a nitrogen atmosphere, and extruded into granules to obtain maleic anhydride grafted polypropylene.

[0047] Among them, the twin-screw extruder is divided into eight sections, and the settings of the twin-screw extruder are as follows:

[0048] Section 1: 150℃, Section 2: 160℃, Section 3: 180℃, Section 4: 190℃, Section 5: 180℃, Section 6: 170℃, Section 7: 170℃, Section 8: 170℃, the main screw speed is 180r / min, and the feeding screw speed is 15r / min.

[0049] Example 2

[0050] A maleic anhydride grafted polypropylene, which is different from Example 1, includes 100 kg of polypropylene, 4 kg of maleic anhydride, 0.6 kg of grafting aid, 0.3 kg of initiator and 0.1 kg of antioxidant.

[0051] The grafting aid is prepared by compounding trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 1:0.9:0.8.

[0052] The initiator is prepared by mixing tert-butyl perbenzoate and diisopropylbenzene peroxide in a mass ratio of 1:0.5.

[0053] Wherein, the preparation method of maleic anhydride grafted polypropylene comprises:

[0054] The raw materials in the above formula amounts were mixed evenly, put into a twin-screw extruder, melted under a nitrogen atmosphere, and extruded into granules to obtain maleic anhydride grafted polypropylene.

[0055] Among them, the twin-screw extruder is divided into eight sections, and the settings of the twin-screw extruder are as follows:

[0056] Stage 1: 160℃, Stage 2: 170℃, Stage 3: 170℃, Stage 4: 170℃, Stage 5: 170℃, Stage 6: 160℃, Stage 7: 160℃, Stage 8: 160℃, the main screw speed is 200r / min, and the feeding screw speed is 20r / min.

[0057] Example 3

[0058] A maleic anhydride grafted polypropylene, which is different from Example 1 in that it includes 120 kg of polypropylene, 5 kg of maleic anhydride, 0.8 kg of grafting aid, 0.4 kg of initiator and 0.2 kg of antioxidant.

[0059] The grafting aid is prepared by compounding trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 1:0.7:1.

[0060] The initiator is a mixture of tert-butyl perbenzoate and diisopropylbenzene peroxide in a mass ratio of 1:0.7.

[0061] Wherein, the preparation method of maleic anhydride grafted polypropylene comprises:

[0062] The raw materials in the above formula amounts were mixed evenly, put into a twin-screw extruder, melted under a nitrogen atmosphere, and extruded into granules to obtain maleic anhydride grafted polypropylene.

[0063] Among them, the twin-screw extruder is divided into eight sections, and the settings of the twin-screw extruder are as follows:

[0064] Stage 1: 150℃, Stage 2: 160℃, Stage 3: 190℃, Stage 4: 180℃, Stage 5: 180℃, Stage 6: 160℃, Stage 7: 160℃, Stage 8: 160℃. The main screw speed is 200r / min and the feeding screw speed is 15r / min.

[0065] Comparative Example 1

[0066] A maleic anhydride grafted polypropylene, which is different from Example 1 in that the grafting auxiliary agent is prepared by compounding ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 0.8:0.9.

[0067] Comparative Example 2

[0068] A maleic anhydride grafted polypropylene, which is different from Example 1 in that the grafting auxiliary agent is trimethylolpropane trimethacrylate and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 1:0.9.

[0069] Comparative Example 3

[0070] A maleic anhydride grafted polypropylene, which is different from Example 1 in that the grafting auxiliary agent is trimethylolpropane trimethacrylate and ethylene propylene diene monomer rubber compounded in a mass ratio of 1:0.8.

[0071] Comparative Example 4

[0072] A maleic anhydride grafted polypropylene, which is different from Example 1 in that no grafting auxiliary agent is added.

[0073] Test 1: Determination of grafting rate by acid-base titration

[0074] Sample: purified maleic anhydride-grafted polypropylene of the above examples and comparative examples.

[0075] Detection method: First, add 100 mL of xylene to dissolve 0.5 g of sample. Heat until completely dissolved, then add phenolphthalein standard solution. Then titrate with 0.01 mol / L sodium hydroxide / ethanol standard solution. After titration, record the amount of titration solution V. Calculate the grafting rate according to the following formula:

[0076] Grafting rate = (V*98.06*0.01) / (0.5*2000)*100%

[0077] The above test results are shown in Table 1.

[0078] Test 2: Performance test of composite materials

[0079] Sample: maleic anhydride grafted polypropylene of the above embodiments and comparative examples.

[0080] Testing method: The sample, polypropylene and short glass fiber were mixed in a mass ratio of 10:70:30 to prepare a polypropylene / short glass fiber composite material. The tensile strength (MPa), flexural strength (MPa) and notched impact strength (KJ / m 2 ).

[0081] The above test results are shown in Table 2.

[0082] Table 1:

[0083] Group Grafting rate / % Example 1 1.83 Example 2 1.76 Example 3 1.81 Comparative Example 1 1.02 Comparative Example 2 1.10 Comparative Example 3 1.13 Comparative Example 4 0.86

[0084] Table 2:

[0085]

[0086]

[0087] Combining Examples 1-3, Comparative Examples 1-4 and Table 1-2, it can be seen that the maleic anhydride grafted polypropylene of Examples 1-3 has good grafting rate and compatibility.

[0088] Specifically analyzing Example 1 and Comparative Examples 1-4, the difference between Example 1 and Comparative Examples 1-4 is that the grafting aid of Example 1 is compounded by trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber, and 4,4-dihydroxydiphenyl sulfide. From the test results, the grafting rate of the maleic anhydride grafted polypropylene of Example 1 is maintained at a high level, and the prepared polypropylene / short glass fiber composite material is superior to Comparative Examples 1-4 in terms of tensile strength, flexural strength, and notched impact strength. Based on the above test results, the applicant deduces that the grafting aid compounded by trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber, and 4,4-dihydroxydiphenyl sulfide has a significant impact on the preparation and performance of maleic anhydride grafted polypropylene. The grafting aid of the present application can effectively increase the grafting rate of maleic anhydride grafted polypropylene and significantly improve the compatibilization of the finished product, thereby obtaining an excellent compatibilizer and enhancing the performance of the composite material.

[0089] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing maleic anhydride grafted polypropylene, characterized in that: include: Step 1: Weigh 100-120 parts of polypropylene, 4-5 parts of maleic anhydride, 0.6-0.8 parts of grafting aid, 0.3-0.4 parts of initiator and 0.1-0.2 parts of antioxidant by mass, and mix them evenly; Step 2: Extruding the mixture into pellets through a twin-screw extruder to obtain maleic anhydride grafted polypropylene; The grafting auxiliary agent is prepared by compounding trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 1: (0.7-0.9): (0.8-1); The brand of the EPDM rubber is TER 4436.

2. The method for preparing maleic anhydride grafted polypropylene according to claim 1, wherein: The initiator is prepared by compounding tert-butyl perbenzoate and dicumyl peroxide in a mass ratio of 1:(0.5-0.7).

3. The method for preparing maleic anhydride grafted polypropylene according to claim 1, wherein: The antioxidant is prepared by compounding antioxidant 1010 and antioxidant 168 in a mass ratio of 1:

1.

4. The method for preparing maleic anhydride grafted polypropylene according to claim 1, wherein: The twin-screw extruder has eight sections, and the reaction temperature of each section is as follows: Stage 1: 150-170℃, Stage 2: 160-170℃, Stage 3: 170-190℃, Stage 4: 170-190℃, Stage 5: 170-180℃, Stage 6: 160-170℃, Stage 7: 160-170℃, Stage 8: 160-170℃.

5. The method for preparing maleic anhydride grafted polypropylene according to claim 4, wherein: The main screw speed of the twin-screw extruder is 180-200 r / min.

6. The method for preparing maleic anhydride grafted polypropylene according to claim 1, wherein: In the step 1, 100 parts of polypropylene, 4.2 parts of maleic anhydride, 0.65 parts of grafting aid, 0.3 parts of initiator and 0.1 parts of antioxidant were weighed in parts by mass.

7. The method for preparing maleic anhydride grafted polypropylene according to claim 6, wherein: The grafting auxiliary agent is prepared by compounding trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 1:0.8:0.

9.

8. A maleic anhydride grafted polypropylene, characterized in that: The maleic anhydride grafted polypropylene is prepared by the preparation method of maleic anhydride grafted polypropylene according to any one of claims 1 to 7.

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