阅读说明：本技术 一种耐高温聚酰胺材料及其制备方法 (High-temperature-resistant polyamide material and preparation method thereof ) 是由 武嘉 亓玉刚 王朝进 田国锋 张全福 毕燕 李亚弛 李慧敏 于 2020-06-19 设计创作，主要内容包括：本发明公开了一种耐高温聚酰胺材料及其制备方法。本发明通过加热-脱水缩合的方法,以成盐、预聚、固相增黏的过程制备耐高温聚酰胺材料,制备的耐高温聚酰胺材料同时包括芳香性聚酰胺组分与短链脂肪性聚酰胺组分,此耐高温聚酰胺材料中的芳香性聚酰胺网络组分中接枝含有短链脂肪性聚酰胺网络组分,形成半结晶性耐高温聚酰胺材料。该耐高温聚酰胺兼具耐高温性和易加工性,可应用于发动机配件、回流焊等方面。(The invention discloses a high-temperature-resistant polyamide material and a preparation method thereof. The invention prepares the high temperature resistant polyamide material by heating-dehydration condensation through the processes of salifying, prepolymerization and solid-phase adhesion, the prepared high temperature resistant polyamide material simultaneously comprises an aromatic polyamide component and a short-chain aliphatic polyamide component, and the aromatic polyamide network component in the high temperature resistant polyamide material is grafted with the short-chain aliphatic polyamide network component to form the semicrystalline high temperature resistant polyamide material. The high-temperature resistant polyamide has high-temperature resistance and easy processability, and can be applied to aspects such as engine accessories, reflow soldering and the like.)

1. The preparation method of the high-temperature-resistant polyamide material is characterized by comprising the following steps of:

1) taking 0.8-1.2 parts by mass of short-chain diamine, 0.4-0.7 part by mass of short-chain dibasic acid, 0.5-0.9 part by mass of aromatic diacid and 1.5-2.5 parts by mass of mixed solvent, dissolving the short-chain diamine, the short-chain diacid and the aromatic diacid in the mixed solvent, and heating and dissolving to form a colorless transparent solution to obtain a high-temperature resistant polyamide salt solution;

2) adding the high-temperature resistant polyamide salt solution obtained in the step 1) into a polymerization kettle, and pre-polymerizing for 1-3 hours at the temperature of 180-300 ℃ for 5-15 minutes for the second time when the temperature is increased to 280-300 ℃;

3) and (3) raising the temperature to 300-310 ℃, vacuumizing for 3-15 minutes, and increasing the pressure in the kettle to extrude and discharge when the viscosity is 1-2.2, so as to obtain the high-temperature-resistant polyamide material.

2. The method of claim 1, wherein the short-chain diamine in step 1) is one of pentamethylenediamine, hexamethylenediamine and decamethylenediamine.

3. The method according to claim 1, wherein the short-chain dibasic acid in the step 1) is one of glutaric acid, adipic acid and sebacic acid.

4. The method according to claim 1, wherein the aromatic diacid in step 1) is one of terephthalic acid, isophthalic acid and phthalic acid.

5. The method according to claim 1, wherein the mixed solvent in step 1) is water and an organic solvent in a mass ratio of 1-1.1:100-200, and the organic solvent is one of ethanol, N-dimethylformamide and N, N-dimethylacetamide.

6. The method of claim 1, wherein the heating in step 1) is carried out at a heating temperature of 80 to 100 ℃ for 0.4 to 1.5 hours.

7. The process according to any one of claims 1 to 7, wherein the increase in the pressure in the vessel in step 3) means that the pressure in the vessel is increased to 0.7 MPa.

Technical Field

The invention relates to a high-temperature-resistant polyamide material and a preparation method thereof, belonging to the field of high polymers.

Background

Polyamides are classified into aliphatic polyamides, wholly aromatic polyamides and semi-aromatic polyamides according to the composition of the monomers. Aliphatic polyamides, such as polycaprolactam (PA6) and polyhexamethylene adipamide (PA66), can be produced by melt processing at low cost, and they have high crystallinity and high crystallization rate, and are widely used in industrial fields. However, PA6 and PA66 have low melting temperature and glass transition temperature, poor dimensional stability, and are not suitable for high temperature environments. Wholly aromatic polyamides, such as poly (p-phenylene terephthalamide) (PPTA) and poly (m-phenylene isophthalamide) (PMIA), are recognized as high performance polymers due to their excellent thermal and physico-mechanical properties due to their high density of rigid aromatic rings and strong inter-chain attraction. However, they have melting points well above the decomposition temperature and are therefore not amenable to post-melt processing and injection molding, and can only be processed in highly polar organic solvents, making their processing prohibitively expensive. Semi-aromatic polyamides, such as polyhexamethylene terephthalamide (PA6T), polynaphthalenediamide (PA9T) and polydecamethylene terephthalamide (PA10T), combine the advantages of wholly aromatic polyamides and aliphatic polyamides, exhibiting excellent high temperature resistance, chemical resistance, dimensional stability and good processability.

The development of semi-aromatic high temperature resistant polyamides has been particularly rapid over the last 20 years. The semi-aromatic high-temperature resistant polyamides which are industrialized at present mainly comprise PA6T, PA9T and PA 10T. Among them, PA6T has a melting point (370 ℃) higher than its decomposition temperature (350 ℃), and therefore, a copolymer of PA6T (CN 109749080A) is mainly present on the market at present. PA6T and its copolymer have a shorter molecular chain and a higher density of amide groups, resulting in a higher water absorption (CN 110818892A). PA9T has a melting point of 308 ℃ and has low water absorption, but the price of PA9T is too expensive due to the complicated preparation process of the polymerized monomer nonane diamine and monopolization of the production of the nonane diamine by Kuraray of Japan. In the 21 st century, PA10T was developed and industrially produced by Jinfa science and technology Co., Ltd in China, and since decamethylene diamine, a main raw material of the PA10T, is castor oil, PA becomes the only bio-based semi-aromatic high temperature resistant polyamide. With the recent increase of environmental awareness, the concept of green development has been infiltrated into various industries (WO 2019/072012 a 1). However, the melting point (316 ℃) of PA10T is close to its decomposition temperature (350 ℃) so that decomposition easily occurs during melt modification and injection molding, and therefore its processability must be improved by widening the processing window. The comprehensive conditions of PA6T, 9T and 10T are synthesized, the processability of the high-temperature-resistant nylon is improved, the high-temperature-resistant nylon has high temperature resistance, and the high-temperature-resistant polyamide material is constructed in the aspects of network structure, preparation materials and process control.

Disclosure of Invention

The invention overcomes the defects of the prior art and provides a high-temperature resistant polyamide material and a preparation method thereof. The invention provides a method for preparing high-temperature-resistant polyamide, which is characterized in that a heating-dehydration condensation method is adopted to prepare a high-temperature-resistant polyamide material through the processes of salifying, prepolymerization and solid-phase tackifying, the prepared high-temperature-resistant polyamide material comprises an aromatic polyamide component and a short-chain aliphatic polyamide component, and the aromatic polyamide network component in the high-temperature-resistant polyamide material is grafted with the short-chain aliphatic polyamide network component to form a semi-crystalline high-temperature-resistant polyamide material.

The high-temperature-resistant polyamide material simultaneously contains an aromatic polyamide component and a short-chain aliphatic polyamide component, wherein the aromatic polyamide component is grafted with the aliphatic polyamide component.

The preparation method for preparing the high-temperature resistant polyamide material comprises the following steps:

1) taking 0.8-1.2 parts by mass of short-chain diamine, 0.4-0.7 part by mass of short-chain dibasic acid, 0.5-0.9 part by mass of aromatic diacid and 1.5-2.5 parts by mass of mixed solvent, dissolving the short-chain diamine, the short-chain diacid and the aromatic diacid in the mixed solvent, and heating and dissolving to form a colorless transparent solution to obtain a high-temperature resistant polyamide salt solution;

2) adding the high-temperature resistant polyamide salt solution obtained in the step 1) into a polymerization kettle, and pre-polymerizing for 1-3 hours at the temperature of 180-300 ℃ for 5-15 minutes for the second time when the temperature is increased to 280-300 ℃;

3) and (3) raising the temperature to 300-310 ℃, vacuumizing for 3-15 minutes, and increasing the pressure in the kettle to extrude and discharge when the viscosity is 1-2.2, so as to obtain the high-temperature-resistant polyamide material.

Further, the short-chain diamine in the step 1) is one of pentamethylene diamine, hexamethylene diamine and decamethylene diamine.

Further, the short-chain dibasic acid in the step 1) is one of glutaric acid, adipic acid and sebacic acid.

Further, the aromatic diacid in the step 1) is one of terephthalic acid, isophthalic acid and phthalic acid.

Further, the mixed solvent in the step 1) is water and an organic solvent which is one of ethanol, N-dimethylformamide and N, N-dimethylacetamide, and is mixed according to a mass ratio of 1-1.1: 100-200.

Further, the heating temperature in the step 1) is 80-100 ℃, and the heating time is 0.4-1.5 hours.

Further, the step of increasing the pressure in the kettle in the step 3) means that the pressure in the kettle is increased to 0.7 MPa.

Has the advantages that:

(1) the invention creatively utilizes short-chain diamine, short-chain diacid and aromatic binary acid to prepare the high-temperature-resistant polyamide material, and can control the viscosity of the supermolecule polyamide by adjusting the pH value of salt and the process. The high-temperature resistant polyamide material comprises aromatic polyamide and short-chain aliphatic polyamide, wherein a network component containing aliphatic polyamide is grafted in the component structure of the aromatic polyamide to form a semi-crystalline high-temperature resistant polyamide material. The high-temperature resistant polyamide has high-temperature resistance and easy processability, and can be applied to aspects such as engine accessories, reflow soldering and the like.

(2) The preparation method of the high-temperature resistant polyamide has the advantages of simple process, easy control and convenient operation, and is suitable for large-scale industrial production.

Drawings

FIG. 1 melting diagram of polyhexamethylene diamine-co-adipic acid-co-phthalic acid.

FIG. 2 melting diagram of polyhexamethylene diamine-co-adipic acid-co-isophthalic acid.

FIG. 3 melting diagram of polyhexamethylene diamine-co-adipic acid-co-terephthalic acid.

Detailed Description

In order to make the technical solutions in the present application better understood, the present invention is further described below with reference to examples, which are only a part of examples of the present application, but not all examples, and the present invention is not limited by the following examples.