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Process for preparing semi-aromatic polyamides

A technology of semi-aromatic and polyamide, which is applied in the field of preparation of semi-aromatic polyamide, can solve the problems of increasing reaction pressure, side reactions, poor product application, etc., and achieves the effect of avoiding loss and improving quality

Inactive Publication Date: 2009-07-29
KINGFA SCI & TECH CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Increasing the pre-polymerization temperature will lead to the occurrence of side reactions, and will also increase the reaction pressure, and the requirements for equipment will also increase accordingly
Draining the water in the reaction will volatilize the unreacted diamine, resulting in a large difference between the monomer unit ratio of the prepolymer and the initial monomer ratio added to the reactor, and it cannot guarantee that the monomer dicarboxylic acid and Molar ratio balance of diamines
[0011] In the existing semi-aromatic polyamide preparation method, dehydration begins when the temperature rises to 230°C. At this time, the amine group value of the prepared semi-aromatic polyamide is far lower than the carboxyl value, which will have a negative impact on the application of the product.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Add 3323g (20mol) of terephthalic acid, 3446g (20mol) of decanediamine, and 73.27g (0.6mol) of benzoic acid into a 20L autoclave equipped with magnetic coupling stirring, condenser, gas phase port, feed port, and pressure explosion-proof port , 6.77g (0.1wt% based on the total weight of the raw material) sodium hypophosphite, 2.2L deionized water, and the temperature was raised after nitrogen purging. The temperature was raised to 170° C. under stirring to start dehydration, and the temperature was raised to 220° C. after dehydration, and the reaction mixture was stirred at 220° C. for 1 hour, and then the temperature of the reactant was raised to 230° C. under stirring. The reaction was continued for 2 hours at a constant temperature of 230° C. and a constant pressure of 2.5 MPa. After the reaction was completed, the material was discharged to obtain a prepolymer with an intrinsic viscosity [η] of 0.152 dl / g. The prepolymer was vacuum-dried at 80°C for 24 hours, and th...

Embodiment 2

[0044] Repeat Example 1, except that the dehydration temperature is changed to 180°C. The results are shown in Table 1.

Embodiment 3

[0046] Repeat Example 1, except that the dehydration temperature is changed to 190°C. The results are shown in Table 1.

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Abstract

The invention discloses a method for preparing semi-aromatic polyamide. The method adopts low temperature of 170 DEG C to 190 DEG C for dehydration firstly, and then adopts a method for temperature-raising and prepolymerization to prepare the semi-aromatic polyamide, thus avoiding the loss of diamine and being capable of accurately controlling the molar ratio of the dicarboxylic acids and the diamine, obtaining the polyamide with high intrinsic viscosity and improving the quality of semi-aromatic polyamide. By the prepolymerization reaction, the prepolymer which is measured in 96 percent of sulphuric acid with the temperature of 25 DEG C and has the intrinsic viscosity Eta of 0.06 to 0.3dl / g can be obtained. After viscosifying reaction, the intrinsic viscosity Eta of the semi-aromatic polyamide is 0.8 to 2.5 dl / g and the melting point of the semi-aromatic polyamide is 270 to 330 DEG C; the content of terminal carboxyl group is 15 to 80 mol / t; and the content of amino-terminated group is 15 to 80 mol / t.

Description

technical field [0001] The invention relates to the preparation technology of semi-aromatic polyamide. Background technique [0002] Aliphatic polyamides, such as PA6 and PA66, have excellent mechanical strength, heat resistance, chemical resistance, wear resistance and self-lubricating properties, and low coefficient of friction. Their applications include electronic appliances, automotive parts, furniture , building materials and fibers, has become one of the most important engineering plastics. [0003] Semi-aromatic polyamide is a polyamide resin prepared by polycondensation of diamines or dicarboxylic acids with aromatic rings and aliphatic dicarboxylic acids or diamines, and is one of the aromatic polyamides. Due to the introduction of aromatic rings into the main chain of polyamide molecules, the heat resistance and mechanical properties are improved, the water absorption rate is reduced, and it has a more suitable performance / price ratio. It is between general engin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G69/28
Inventor 罗湘安蔡彤旻曾祥斌曹民陈健
Owner KINGFA SCI & TECH CO LTD
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