CN-119039487-B - Modified polypropylene and preparation method and application thereof

Abstract

The invention provides modified polypropylene and a preparation method and application thereof, wherein the preparation method comprises the following steps of adding an initiator into a first raw material system to perform a first grafting reaction to obtain a first grafting product; and enabling the first grafting product and a second raw material system to generate a second grafting reaction to obtain modified polypropylene, wherein the first raw material system comprises first polypropylene, glycidyl methacrylate and styrene, and the second raw material system comprises second polypropylene and carboxylic acid compounds with hindered phenol groups. Through two-step grafting reaction, the hindered phenol group is partially grafted on the polypropylene, so that the defect that an antioxidant is easy to separate out can be effectively overcome, and the modified polypropylene with excellent extraction resistance and thermal oxygen stability is finally obtained.

Inventors

• WANG ZHUONI
• HUANG ANPING
• LI GUANGQUAN
• YANG XIN
• FENG JIACHUN
• CHENG PENGFEI
• GAO LIN
• TANG JING
• TU XIAOYAN
• WU JIAN

Assignees

• 中国石油天然气股份有限公司

Dates

Publication Date

20260512

Application Date

20230529

Claims (8)

1. 1. The preparation method of the modified polypropylene is characterized by comprising the following steps of: adding an initiator into the first raw material system to perform a first grafting reaction to obtain a first grafting product; enabling the first grafting product and a second raw material system to generate a second grafting reaction to obtain modified polypropylene; Wherein the first raw material system comprises first polypropylene, glycidyl methacrylate and styrene; the second raw material system comprises a carboxylic acid compound containing a hindered phenol group and second polypropylene, wherein the first raw material system comprises, by mass, 100 parts of first polypropylene, 1-20 parts of glycidyl methacrylate, 1-20 parts of styrene and 0.1-5 parts of an initiator; the second raw material system comprises, by mass, 100 parts of second polypropylene, 1-30 parts of first grafted products, and 0.1-10 parts of carboxylic acid compounds containing hindered phenol groups; the carboxylic acid compound containing hindered phenol groups is selected from 3, 5-di-tert-butyl-4-hydroxyphenyl fatty acid.
2. 2. The method according to claim 1, wherein the carboxylic acid compound containing a hindered phenol group is at least one selected from the group consisting of 3, 5-di-t-butyl-4-hydroxyphenylpropionic acid, 3, 5-di-t-butyl-4-hydroxyphenylcarboxylic acid, and 3, 5-di-t-butyl-4-hydroxyphenylacetic acid.
3. 3. The method according to any one of claims 1 to 2, wherein the first grafting reaction temperature is 170 ℃ to 280 ℃ and the second grafting reaction temperature is 160 ℃ to 280 ℃.
4. 4. The process according to any one of claim 1 to 2, wherein, The first raw material system comprises, by mass, 100 parts of first polypropylene, 10-20 parts of glycidyl methacrylate, 10-14 parts of styrene and 0.5-2 parts of an initiator; the second raw material system comprises, by mass, 100 parts of second polypropylene, 4-25 parts of first grafted products, and 0.5-2 parts of carboxylic acid compounds containing hindered phenol groups.
5. 5. The method according to any one of claims 1 to 2, wherein the initiator is at least one selected from dicumyl peroxide and di-t-butyl peroxide.
6. 6. Modified polypropylene, characterized in that it is obtained according to the preparation process according to any one of claims 1 to 5.
7. 7. The modified polypropylene according to claim 6, wherein the mass content of the hindered phenol group in the modified polypropylene is 0.01 to 5%.
8. 8. A polypropylene article comprising the modified polypropylene of claim 6 or 7.

Description

Modified polypropylene and preparation method and application thereof Technical Field The invention belongs to the technical field of high polymer materials, and particularly relates to modified polypropylene and a preparation method and application thereof. Background Polypropylene is subjected to light and heat and oxidized by oxygen in the air, resulting in loss of mechanical properties. Therefore, it is necessary to add an antioxidant to polypropylene to improve the thermo-oxidative stability of polypropylene, and to delay or inhibit the progress of the thermo-oxidative process of polypropylene, thereby preventing the aging of polypropylene and extending its service life. The hindered phenol antioxidant is a compound with hydroxyl on a benzene ring and substituent groups on one side or two sides of the hydroxyl, has the advantages of low volatility, strong antioxidant capacity and the like, is widely applied to polypropylene and is used for reducing the thermo-oxidative aging of the polypropylene. However, since polypropylene is nonpolar and hindered phenol antioxidants are polar, the compatibility of the two is poor. In practical application, the hindered phenol antioxidant is easy to migrate and separate out to the surface of the polypropylene product, thereby affecting the appearance and the thermo-oxidative stability of the polypropylene. At present, most of polypropylene is chemically modified and then mixed with an antioxidant to enhance the thermal stability of polypropylene, for example, patent document CN109439240A discloses a preparation method of a heat-resistant PP hot melt adhesive, amino acid is grafted on polypropylene by chemical grafting modification, and after the grafted product is mixed with the antioxidant, the mixture is completely melted with terpene phenolic resin and a hybrid composite material to prepare the heat-resistant polyolefin hot melt adhesive so as to enhance the thermal stability of polypropylene. The patent document CN106633267A discloses synthesis of a reactive hindered phenol antioxidant polyolefin auxiliary agent, wherein the synthesized allyl hindered phenol auxiliary agent is used for carrying out melt grafting blending with polyolefin, namely the reactive hindered amine antioxidant polyolefin auxiliary agent, the reactive hindered phenol antioxidant polyolefin auxiliary agent, an initiator and polyolefin resin are placed in a screw blender for carrying out melt blending grafting, and a peroxide initiator is added in the processing process to connect the hindered phenol antioxidant polyolefin auxiliary agent to a macromolecular chain, so that the addition of the peroxide initiator can cause degradation of matrix PP and reduce mechanical properties of the material. Therefore, how to overcome the defect that the antioxidant is easy to migrate and separate out, and provide a polypropylene material with good extraction resistance and good thermo-oxidative stability, which is a technical problem to be solved in the field. Disclosure of Invention The invention provides a preparation method of modified polypropylene, which enables hindered phenol groups to be grafted on polypropylene through two-step grafting reaction, can effectively overcome the defect that an antioxidant is easy to separate out, and finally obtains the modified polypropylene with excellent extraction resistance and thermal oxygen stability. The present invention provides a modified polypropylene which is excellent in extraction resistance and thermal oxygen stability. The invention provides a polypropylene product, which has excellent service performance and long service cycle due to the inclusion of the modified polypropylene. In one aspect of the present invention, there is provided a method for preparing a modified polypropylene, comprising the steps of: adding an initiator into the first raw material system to perform a first grafting reaction to obtain a first grafting product; enabling the first grafting product and a second raw material system to generate a second grafting reaction to obtain modified polypropylene; adding an initiator into the first raw material system to perform a first grafting reaction to obtain a first grafting product; enabling the first grafting product and a second raw material system to generate a second grafting reaction to obtain modified polypropylene; the first raw material system comprises first polypropylene, glycidyl methacrylate and styrene, and the second raw material system comprises carboxylic acid compounds containing hindered phenol groups and second polypropylene. A method of making as described above wherein said hindered phenol group is selected from 3, 5-di-tert-butyl-4-hydroxyphenyl. The preparation method as described above, wherein the hindered phenol group-containing carboxylic acid compound is selected from 3, 5-di-t-butyl-4-hydroxyphenyl fatty acids. The preparation method as described above, wherein the carboxylic acid compound containing a hin