CN111978192A

CN111978192A - Preparation method of polypropylene nucleating agent

Info

Publication number: CN111978192A
Application number: CN201910444400.4A
Authority: CN
Inventors: 曹晨刚; 潘峥
Original assignee: Tianjin University of Science and Technology
Current assignee: Tianjin University of Science and Technology
Priority date: 2019-05-21
Filing date: 2019-05-21
Publication date: 2020-11-24

Abstract

The invention discloses a preparation method of a polypropylene nucleating agent. The nucleating agent is an aromatic amide compound which can induce polypropylene crystallization. The preparation method of the compound is obtained by simple chemical reaction of 1, 3, 5-benzene trimethyl acyl chloride and alkylamine. The compound is a good polypropylene crystallization nucleating agent, the beta crystal form content in polypropylene crystals is more than 80%, the crystal size is reduced by 70%, and the transparency of polypropylene products can be obviously improved.

Description

Preparation method of polypropylene nucleating agent

Technical Field

The invention relates to a preparation method of a polypropylene nucleating agent.

Background

Although polypropylene has good mechanical properties, its application in medical supplies, packaging and daily necessities is greatly restricted due to poor transparency. By adding the nucleating agent into the polypropylene, the advantages of light weight, low cost and easy processing are maintained, and the transparency and other properties of the polypropylene are also greatly improved compared with the common polypropylene. Under different environments, the polypropylene can obtain five types of alpha, beta, gamma, pseudo-hexagons and the like, wherein alpha and beta crystal forms are common. PP with different crystal forms has different crystallization parameters and processing and application properties.

The alpha crystal form is a monoclinic system, is the most common form of the formed crystal forms, and is also the most stable crystal form, and the current commercialized polypropylene nucleating agent mainly induces polypropylene to generate the alpha crystal form, but the spherulite formed by the alpha crystal form has larger size, and the size is larger than the wavelength of incident light, so that the transparency of a product is poor.

The beta crystal form is another common crystal form of polypropylene, belongs to a hexagonal crystal system, is in a metastable state, and can only be rapidly cooled to a certain temperature in a specific temperature gradient field or under the action of shear stress or in a molten state to be crystallized at an isothermal temperature to obtain the beta crystal form polypropylene. The beta crystalline form is very effective for the performance improvement of polypropylene materials. Currently, beta-nucleating agents are relatively few.

Disclosure of Invention

Based on the above background, the present invention provides an aromatic amide compound having a structure represented by formula (1),

wherein R is methyl, ethyl, propyl or cyclohexyl.

The aromatic amide compound can be prepared by the following method: adding 100-200ml of N-methylpyrrolidone, most preferably 50-100ml of N-methylpyrrolidone and 5-20ml of triethylamine into 10-30ml of methylamine, ethylamine or propylamine, most preferably 5-10ml of cyclohexylamine, dripping 5-10g of 1, 3, 5-benzene tricarboxychloride at the temperature of 0-5 ℃, reacting for 4-8h at the temperature of 50-80 ℃, precipitating, filtering, drying in a drying box, and obtaining the aromatic amide compound nucleating agent.

The aromatic amide compound can induce polypropylene to crystallize by blending with polypropylene to generate a beta crystal form with the content of more than 80%, and the transparency of a polypropylene product can be obviously improved while the original performance of the polypropylene is kept.

Detailed Description

Example 1

In a 500ml three-necked flask, 10ml of cyclohexylamine and 2.0g of lithium chloride for drying were charged, followed by 200ml of N-methylpyrrolidone and 20ml of triethylamine, and stirred in an ice-water bath until the temperature became 5 ℃. The weighed 6.3g of 1, 3, 5-benzenetricarbonyl chloride reagent was dissolved in a separating funnel containing 40ml, and slowly added dropwise at a dropping rate of 2-3s to the mixed solution, the solution in the three-necked flask changed from colorless clear liquid to yellow turbid liquid which is not clear any more, and after the addition was successful, the solution was heated to 75 ℃ with stirring. After reacting for 4 hours, stopping stirring, pouring the obtained product into 300ml of ice-water mixture, precipitating, filtering, putting the product into a drying oven for 5 hours, and taking out the product to obtain the 1, 3, 5-benzenetricarboxylic acid tri (cyclohexylamine) nucleating agent with the yield of 89%.

Example 2

Extruding and granulating at 210 ℃ under the blending action of the 1, 3, 5-benzenetricarboxylic acid (cyclohexylamine) nucleating agent and polypropylene, and repeatedly extruding twice to obtain the polypropylene composite material with the nucleating agent content of 0.25 wt%. The tensile strength is increased by 20.32%, and the haze is reduced by 81%.

Claims

1. An aromatic amide compound has a structure shown in a formula (1),

wherein R is methyl, ethyl, propyl or cyclohexyl.

2. The process for producing an aromatic amide compound according to claim 1, which comprises the main steps of: adding 100-200ml of N-methyl pyrrolidone and 5-20ml of triethylamine into 10-30ml of alkylamine, dripping 5-10gl, 3, 5-benzene tricarboxychloride at the temperature of 0-5 ℃, reacting for 4-8h at the temperature of 50-80 ℃, precipitating the precipitate, filtering, drying in a drying oven, and obtaining the aromatic amide compound nucleating agent.

3. A process for producing an aromatic amide compound as claimed in claim 2, wherein the alkylamine is methylamine, ethylamine, propylamine or cyclohexylamine.

4. The aromatic amide compound of claim 1, wherein the compound can induce polypropylene crystallization to form beta-form with content of more than 80%, and can significantly improve transparency of polypropylene products.