Maleic anhydride grafted polypropylene and preparation method thereof

Abstract

The invention relates to the technical field of polypropylene production, in particular to maleic anhydride grafted polypropylene and a preparation method thereof. The invention relates to a preparation method of maleic anhydride grafted polypropylene, which comprises the following steps: weighing 100-120 parts of polypropylene, 4-5 parts of maleic anhydride, 0.6-0.8 part of a grafting auxiliary agent, 0.3-0.4 part of an initiator and 0.1-0.2 part of an antioxidant, uniformly mixing, and extruding and granulating by a double-screw extruder to obtain the maleic anhydride grafted polypropylene, wherein the grafting auxiliary agent is prepared by compounding trimethylolpropane trimethacrylate, ethylene propylene diene monomer and 4, 4-dihydroxy diphenyl sulfide according to a mass ratio of 1: (0.7 to 0.9): (0.8 to 1). According to the preparation method disclosed by the invention, the grafting rate of the maleic anhydride grafted polypropylene can be remarkably improved, the compatibility of the polypropylene and a polar material is remarkably improved, and the maleic anhydride grafted polypropylene prepared by the preparation method disclosed by the invention is a compatibilizer with good performance.

Description

Technical Field

[0001] The 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 decreased 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, which can effectively improve the compatibility of polypropylene with inorganic materials and polar polymers, and broaden its application field.

[0003] Maleic anhydride grafted polypropylene is usually prepared by melt extrusion, but the traditional maleic anhydride grafted polypropylene has a low grafting rate. This is because a series of side reactions such as chain breaking, degradation, and chain transfer will 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. The compatibility of the maleic anhydride grafted polypropylene obtained in this way is greatly reduced, and it is difficult to improve the compatibility of polypropylene with inorganic materials and polar polymers. Therefore, it is necessary to develop a new preparation method for maleic anhydride grafted polypropylene to increase the grafting rate of maleic anhydride and polypropylene, thereby further improving the compatibility of polypropylene with polar materials. Summary of the invention

[0004] In order to solve the problem of 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. The present application introduces a grafting aid compounded from trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide into the preparation method of maleic anhydride grafted polypropylene, thereby significantly improving the grafting rate of maleic anhydride grafted polypropylene, thereby significantly improving the compatibility of polypropylene with polar materials.

[0005] In the first aspect, the present application provides a method for preparing maleic anhydride grafted polypropylene, using the following technical solution: A method for preparing maleic anhydride grafted polypropylene, characterized by comprising: 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 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).

[0006] In the above technical scheme, the present application achieves a high grafting rate of maleic anhydride and polypropylene by introducing a grafting aid of a specific ratio. Specifically, trimethylolpropane trimethacrylate can provide multiple active sites to promote the grafting reaction of maleic anhydride and polypropylene, and the addition of ethylene propylene rubber and 4,4-dihydroxydiphenyl sulfide further improves the dispersibility of maleic anhydride in polypropylene. The present application can give full play to its synergistic effect by compounding trimethylolpropane trimethacrylate, ethylene propylene rubber and 4,4-dihydroxydiphenyl sulfide into a grafting aid in a specific mass ratio, which can 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.

[0007] Preferably, the initiator is prepared by compounding tert-butyl perbenzoate and dicumyl peroxide in a mass ratio of 1:(0.5-0.7).

[0008] In the above technical scheme, the present application can more accurately control the progress of the grafting reaction by introducing a compound of tert-butyl perbenzoate and diisopropylbenzene peroxide as an initiator, thereby further improving the grafting efficiency of maleic anhydride and polypropylene. Tert-butyl perbenzoate and diisopropylbenzene peroxide are two common organic peroxides, which have different activities when initiating free radical reactions on the polypropylene molecular chain, and can ensure the continuous progress of the grafting reaction.

[0009] Preferably, the antioxidant is a compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0010] In the above technical scheme, 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.

[0011] Preferably, 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℃.

[0012] In the above technical solution, the present application provides suitable temperature conditions for the preparation of maleic anhydride grafted polypropylene by accurately controlling the reaction temperature of each section of the twin-screw extruder. This temperature gradient design can not only ensure the full contact and reaction between maleic anhydride and polypropylene molecular chains, but also further reduce the side reactions in the reaction process, thereby ensuring the grafting rate and finished product quality of maleic anhydride grafted polypropylene.

[0013] Preferably, the main engine screw speed is 180-200r / min.

[0014] In the above technical solution, the present application ensures the full mixing and reaction of maleic anhydride grafted polypropylene in the twin-screw extruder by precisely controlling the rotation speed of the main screw. The appropriate rotation speed can accelerate the flow and mixing of the material in the extruder and improve the uniformity and efficiency of the grafting reaction.

[0015] 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 by mass.

[0016] Preferably, the grafting aid is a compound of trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 1:0.8:0.9.

[0017] In the above technical solution, the present application further improves the grafting rate and finished product quality of maleic anhydride grafted polypropylene by further optimizing the formula. Under such a ratio of polypropylene, maleic anhydride, grafting aid, initiator and antioxidant, it is possible to better promote the dispersion of maleic anhydride in polypropylene, increase the grafting probability of maleic anhydride and polypropylene, and improve the grafting rate of maleic anhydride grafted polypropylene, thereby obtaining maleic anhydride grafted polypropylene with better compatibility with polar materials.

[0018] In the second aspect, the present application also provides a maleic anhydride grafted polypropylene, which adopts the following technical solution: A maleic anhydride grafted polypropylene is prepared by the preparation method of the maleic anhydride grafted polypropylene as described in the first aspect.

[0019] In the above technical solution, the maleic anhydride grafted polypropylene of the present application is prepared by the preparation method as described in the first aspect. Such maleic anhydride grafted polypropylene has a high grafting rate and good compatibility with polar materials, and has broad application prospects in the fields of plastic modification, coatings, adhesives, etc. In addition, the maleic anhydride grafted polypropylene of the present application can also be used as a compatibilizer to improve the compatibility between different polymers and broaden the application range of polymer materials.

[0020] In summary, this application includes the following beneficial technical effects: 1. The present application introduces a grafting aid compounded from trimethylolpropane trimethacrylate, ethylene propylene diene monomer rubber and 4,4-dihydroxydiphenyl sulfide. The three cooperate with each other and interact with each other in multiple dimensions, such as providing active sites for grafting reactions, improving the dispersibility of maleic anhydride and stabilizing the free radicals of polypropylene macromolecules, 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.

[0021] 2. The present application further optimizes the initiator and the antioxidant, thereby further ensuring the smooth progress of the grafting reaction of maleic anhydride grafted polypropylene and further improving the grafting rate of maleic anhydride grafted polypropylene.

[0022] 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

[0023] 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.

[0024] Unless otherwise specified, the raw materials used in the following specific embodiments are all common commercial products and can be purchased from the market.

[0025] Polypropylene: Source: Sinopec, brand EPT30R.

[0026] Maleic anhydride: source: Shanghai MacLean Biochemical Technology Co., Ltd., industrial grade, purity ≥99%.

[0027] Trimethylolpropane trimethacrylate: Source: Youming (Shanghai) Chemical Co., Ltd., brand Changxing, grade EM331 TMPTMA.

[0028] EPDM rubber: Source: Guangzhou Degao New Materials Co., Ltd., brand: Eni, grade: TER 4436.

[0029] 4,4-Dihydroxydiphenyl sulfide: Source: Hubei Xingyan New Material Technology Co., Ltd.

[0030] Antioxidant 1010: Originated from Dongguan Xingyuan Chemical Co., Ltd., chemical name: pentaerythritol tetrakis[B-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0031] Antioxidant 168: Originated from Dongguan Xingyuan Chemical Co., Ltd., chemical name: tris(2,4-di-tert-butylphenyl) phosphite.

[0032] Twin-screw extruder: from Nanjing Rubber & Plastic Machinery Factory Co., Ltd., model is SJSH-30.

[0033] Example 1 A maleic anhydride grafted polypropylene comprises 100 kg of polypropylene, 4.2 kg of maleic anhydride, 0.65 kg of grafting aid, 0.3 kg of initiator and 0.1 kg of antioxidant.

[0034] The grafting auxiliary agent is prepared by compounding trimethylolpropane trimethacrylate, ethylene propylene rubber and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 1:0.8:0.9.

[0035] The initiator is a compound of tert-butyl perbenzoate and diisopropylbenzene peroxide in a mass ratio of 1:0.6.

[0036] The antioxidant is prepared by compounding antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0037] Wherein, the preparation method of maleic anhydride grafted polypropylene comprises: The raw materials in the above formula were mixed evenly, put into a twin-screw extruder, melted and extruded into granules under a nitrogen atmosphere to obtain maleic anhydride grafted polypropylene.

[0038] Among them, the twin-screw extruder is divided into eight sections, and the twin-screw extruder is set as follows: 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 engine screw speed is 180r / min, and the feeding screw speed is 15r / min.

[0039] Example 2 A maleic anhydride grafted polypropylene, which is different from Example 1 in that it 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.

[0040] The grafting aid is prepared by compounding trimethylolpropane trimethacrylate, ethylene propylene rubber and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 1:0.9:0.8.

[0041] The initiator is a compound of tert-butyl perbenzoate and diisopropylbenzene peroxide in a mass ratio of 1:0.5.

[0042] Wherein, the preparation method of maleic anhydride grafted polypropylene comprises: The raw materials in the above formula were mixed evenly, put into a twin-screw extruder, melted and extruded into granules under a nitrogen atmosphere to obtain maleic anhydride grafted polypropylene.

[0043] Among them, the twin-screw extruder is divided into eight sections, and the twin-screw extruder is set as follows: 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 engine screw speed is 200r / min, and the feeding screw speed is 20r / min.

[0044] Example 3 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.

[0045] The grafting aid is prepared by compounding trimethylolpropane trimethacrylate, ethylene propylene rubber and 4,4-dihydroxydiphenyl sulfide in a mass ratio of 1:0.7:1.

[0046] The initiator is a compound of tert-butyl perbenzoate and diisopropylbenzene peroxide in a mass ratio of 1:0.7.

[0047] Wherein, the preparation method of maleic anhydride grafted polypropylene comprises: The raw materials in the above formula were mixed evenly, put into a twin-screw extruder, melted and extruded into granules under a nitrogen atmosphere to obtain maleic anhydride grafted polypropylene.

[0048] Among them, the twin-screw extruder is divided into eight sections, and the twin-screw extruder is set as follows: 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 engine screw speed is 200r / min, and the feeding screw speed is 15r / min.

[0049] Comparative Example 1 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.

[0050] Comparative Example 2 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 compounded in a mass ratio of 1:0.9.

[0051] Comparative Example 3 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.

[0052] Comparative Example 4 A maleic anhydride grafted polypropylene, which is different from Example 1 in that no grafting aid is added.

[0053] Test 1: Determination of grafting rate by acid-base titration Sample: the purified maleic anhydride grafted polypropylene of the above embodiments and comparative examples.

[0054] Detection method: First add 100mL of xylene to dissolve 0.5g of sample, heat until completely dissolved, then add phenolphthalein calibration solution, and then titrate with 0.01mol / L sodium hydroxide / ethanol standard solution. After titrating until it turns red, record the amount of titration solution V, and calculate the grafting rate according to the following formula: Grafting rate = (V*98.06*0.01) / (0.5*2000)*100% The above test results are shown in Table 1.

[0055] Test 2: Performance test of composite materials Sample: maleic anhydride grafted polypropylene of the above embodiments and comparative examples.

[0056] 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 ).

[0057] The above test results are shown in Table 2.

[0058] Table 1: 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 Table 2: 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.

[0059] Specifically combined with 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 rubber and 4,4-dihydroxydiphenyl sulfide. From the test results, the grafting rate of 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, bending strength and notched impact strength. Based on the above test results, the applicant thus infers that the grafting aid compounded by trimethylolpropane trimethacrylate, ethylene propylene rubber and 4,4-dihydroxydiphenyl sulfide has an important influence on the preparation and performance of maleic anhydride grafted polypropylene. The grafting aid of the present application can effectively improve the grafting rate of maleic anhydride grafted polypropylene, and can also significantly improve the compatibilization of the finished product, obtain a compatibilizer with excellent performance, and enhance the performance of the composite material.

[0060] 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 modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

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 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).

2. The method for preparing maleic anhydride grafted polypropylene according to claim 1, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: The main engine screw has a rotation speed of 180-200 r / min.

6. The method for preparing maleic anhydride grafted polypropylene according to claim 1, characterized in that: 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 are weighed by mass.

7. The method for preparing maleic anhydride grafted polypropylene according to claim 6, characterized in that: 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 as described in any one of claims 1 to 7.

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