Preparation method of semi-aromatic polyamide

A semi-aromatic and polyamide technology, applied in the field of preparation of semi-aromatic polyamides, can solve the problems of difficult control of monomer ratio, incomplete reaction, difficult solid-liquid separation, etc., and achieves less harsh preparation conditions and avoids mixing. The effect of ratio imbalance and easy industrial promotion

Inactive Publication Date: 2020-02-28
JIANGMEN DENGZHONGTAI ENG PLASTICS CO LTD
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

The problem with the one-step preparation of semi-aromatic polyamides is that it is difficult to control the proportion of monomers, because the industrial preparation of semi-aromatic polyamides is made by reaction and polycondensation in a high-temperature and high-pressure environment, and monomeric diamines are produced in high-temperature environments. Volatile, it will cause imbalance of monomer ratio, resulting in poor physical properties of semi-aromatic polyamide resin obtained after polymerization
Although the two-step preparation of semi-aromatic polyamide can effectively control the ratio of monomers, since the long carbon chain semi-aromatic nylon salt and aromatic dibasic acid are basically insoluble in water, the salt formed by the reaction will adhere to the unreacted aromatic polyamide. family dibasic acid surface, resulting in incomplete reaction, inaccurate determination of the reaction end point, the purity of nylon salt is reduced, so there are difficulties in the synthesis of long carbon chain semi-aromatic nylon salt
In addition, the two-step method also has complex process and low yield. The long carbon chain nylon salt prepared by organic solvent has finer particles and difficult solid-liquid separation, which is easy to cause the loss of nylon salt, and the long carbon chain nylon salt prepared by organic solvent Need to wash with a lot of water to remove problems such as organic solvents

Method used

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  • Preparation method of semi-aromatic polyamide
  • Preparation method of semi-aromatic polyamide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0082] In this example, a semi-aromatic polyamide is actually prepared, and the steps include:

[0083] (1) Put 1344.6g (8.1mol) of terephthalic acid, 149.4g (0.9mol) of isophthalic acid, 1548g (9mol) of decanediamine, 5Kg of ethanol and 5kg of deionized water in a magnetically coupled stirring, condensing In a 20L autoclave with pipe, exhaust port and pressure explosion-proof port, heat up to 90°C and keep it warm for 30min;

[0084] (2) Control the temperature at 90°C, evaporate and collect the condensed ethanol, and the collected ethanol can be reused until no obvious fraction is distilled out;

[0085] (3) Add 24.4g (0.2mol) of benzoic acid and 8g of sodium hypophosphite and continue to heat up to 300°C. During this period, the water is slowly discharged, and the pressure is maintained at 2.5MPa, and then reduced to 0.6MPa, and the semi-aromatic is obtained by discharging. The polyamide prepolymer can be obtained after being crushed and increased in solid phase at 200°C f...

Embodiment 2

[0088] In this example, a semi-aromatic polyamide is actually prepared, and the steps include:

[0089] (1) Put 1660g (10mol) of terephthalic acid, 2043g (10.2mol) of dodecanediamine, 8Kg of ethanol and 4kg of deionized water in a place equipped with magnetic coupling stirring, condenser, exhaust port and pressure explosion-proof port In a 20L autoclave, heat up to 80°C and keep warm for 30min;

[0090] (2) Control the temperature at 90°C, evaporate and collect the condensed ethanol, and the collected ethanol can be reused until no obvious fraction is distilled out;

[0091] (3) Add 12.2g (0.1mol) of benzoic acid and 10g of sodium hypophosphite and continue to heat up to 310°C. During this period, the water is slowly discharged to maintain the pressure of 3.5MPa, and then the pressure is reduced to 0.6MPa, and the semi-aromatic poly The amide prepolymer can be obtained after being crushed and increased in solid phase at 240°C for 2 hours.

[0092] Test its intrinsic viscosit...

Embodiment 3

[0094] In this example, a semi-aromatic polyamide is actually prepared, and the steps include:

[0095](1) Put 1660g (10mol) of terephthalic acid, 1614g (10.2mol) of nonanediamine, 5Kg of ethanol and 10kg of deionized water in a 20L high pressure equipped with magnetic coupling stirring, condenser, exhaust port and pressure explosion-proof port In the kettle, heat up to 95°C and keep warm for 30min;

[0096] (2) Control the temperature at 90°C, evaporate and collect the condensed ethanol, and the collected ethanol can be reused until no obvious fraction is distilled out;

[0097] (3) Without adding 46.6g (0.5mol) of aniline, continue to heat up to 310°C, during which the water is slowly discharged, and the pressure is maintained at 3MPa, and then the pressure is reduced to 0.6MPa, and the semi-aromatic polyamide prepolymer is obtained by discharging, which is crushed After solid phase thickening at 200°C for 4h, it can be obtained.

[0098] Test its intrinsic viscosity, melt...

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Abstract

The invention provides a preparation method of semi-aromatic polyamide. The preparation method comprises the following steps: adding an aqueous solution of dibasic acid, diamine and fatty alcohol intoa reaction kettle to prepare a semi-aromatic nylon salt, evaporating the alcohol to remove the alcohol, and carrying out polymerizing to obtain the semi-aromatic polyamide. According to the preparation method, based on the characteristic that the long-carbon-chain semi-aromatic nylon salt has low solubility in water or alcohol but good solubility in a mixed solution of alcohol and water, dibasicacid and diamine are used as raw materials, the long-carbon-chain semi-aromatic nylon salt is prepared in the aqueous solution of fatty alcohol, then a distillation temperature is controlled, the fatty alcohol is removed through evaporation before a polymerization reaction temperature is reached, and heating is continued and polymerization is performed to obtain the semi-aromatic polyamide, thereby avoiding proportion imbalance caused by the volatile loss of diamine in a high-temperature environment.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a preparation method of semi-aromatic polyamide. Background technique [0002] Polyamide is commonly known as nylon, and it is also called nylon when used as fiber. Polyamides can be classified into aliphatic polyamides, polyimides, copolyamides, fully aromatic polyamides and semiaromatic polyamides. [0003] Semi-aromatic polyamides are synthesized by condensation polymerization of aliphatic dibasic amines or dibasic acids and aromatic dibasic acids or dibasic amines. The characteristics of semi-aromatic polyamides are: the glass transition temperature is mostly above 100°C, and the heat resistance is good; the heat and oxygen aging resistance is good; the electrical insulation performance is good; the water absorption of the product is small and the dimensional stability is good; Compared with aromatic polyamide, it has better processing performance; its...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G69/26C08G69/28
CPCC08G69/26C08G69/265C08G69/28
Inventor 曾建平
Owner JIANGMEN DENGZHONGTAI ENG PLASTICS CO LTD
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