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Method for preparing high temperature nylon

A nylon, high-temperature technology, applied in the field of polymer material preparation, can solve the problems of difficult operation, increased thermal history, gelation, etc.

Active Publication Date: 2008-06-18
北京瑞宝知春时代印刷技术开发有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage is that the preparation process needs to be kept in a high temperature environment for a long time, so that the diamine component is extremely volatile during the high temperature polymerization process, and the polymerization time is long, which easily causes side reactions such as thermal degradation and gelation, which seriously Affects the quality of semi-aromatic polyamides
Potential polyamide degradation due to increased heat history due to prolonged reaction time
In addition, special polymerization equipment is required, because the commonly used stirring equipment cannot obtain enough power to keep the molten polyamide in the polymerization tank uniform, resulting in uneven molecular weight distribution of the synthesized nylon resin.
Moreover, compared with transferring low-viscosity polyamide, the operation of transferring molten medium / high viscosity polyamide out of the polymerization tank is much more difficult, and the amount of residual polyamide attached to the inner wall of the polymerization tank is also larger

Method used

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  • Method for preparing high temperature nylon
  • Method for preparing high temperature nylon
  • Method for preparing high temperature nylon

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preparation example Construction

[0063] Each step of the preparation method of the present invention is described in detail below:

[0064] three-step polymerization

[0065] The high temperature nylon (HPN) of the present invention is prepared by the following method.

[0066] Firstly, nylon salt is prepared at low temperature, and then the primary condensate is made under specific conditions, and then through the later solid-state polycondensation step, so as to achieve a high degree of polymerization. This is a three-step polymerization method.

[0067] For example:

[0068] (a) dissolving the aromatic dibasic acid with a content ≥ 99% in 2 to 5 times as much deionized water, heating to 60 to 130°C, preferably 80 to 100°C while stirring;

[0069] (b) dissolving the diamine in 1-3 times deionized water, and heating to 60-120°C, preferably 80-100°C while stirring;

[0070] (c) The two raw materials are injected into the mixed reaction kettle with a metering pump according to an equimolar ratio to react, t...

Embodiment 1

[0103] Add 166.13Kg of terephthalic acid into the dissolution tank, then add twice as much deionized water, and heat to 100°C while stirring. At the same time, 116.21 Kg of hexamethylenediamine was added into 1 times deionized water, and dissolved at a temperature of 80°C. Use metering pumps to send the two solutions into the mixer at the same time, and then into the neutralization tank, and control the neutralization temperature to 90°C and pH 7.1 to 7.2. The reactant enters the crystallizer and is cooled by chilled water to reduce the temperature to 25°C and form crystals. The material was put into a centrifuge, and 266.25Kg of wet nylon 6T salt was obtained after separation, with a yield of 94.3% and a water content of 13.6%. The melting point of nylon salt is 284.9°C, the content of free acid is 0.15%, and the content of free amine is 0.21%.

[0104] Add 3150g of terephthalic acid and hexamethylenediamine salt, 2100g of hexamethylene diammonium adipate (66 salt), 20g of ...

Embodiment 2

[0108] The salt that 3250g terephthalic acid and hexamethylenediamine form, 2100g hexamethylene diammonium adipate (66 salts), 40g acetic acid, 5g sodium hypophosphite monohydrate and 2.5 liters of distilled water are added to a 20L polymerization kettle, and then according to Example 1 The heating operation was performed to obtain a prepolymer having an intrinsic viscosity of 0.14 dl / g and a molecular weight distribution of 5.3. The prepolymer was dried under reduced pressure at 100° C. for 12 hours, and pulverized into particles having a particle diameter of not more than 2 mm. The particles were subjected to solid-state polymerization at 230° C. and a pressure of -0.1 MPa for 4 hours to obtain white high-temperature nylon (HPN) with an intrinsic viscosity [η] of 1.14 dl / g, a molecular weight distribution of 1.9, and a crystallization enthalpy of 62.24 J / g, heat distortion temperature is 157°C.

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Abstract

The present invention provides a preparation method of high-temperature nylon, including the following steps: (a) dicarboxylic acid and diamine are used to prepare 6T salt or 6I salt under the temperature of 80 to 110 DEG C and the carbon atomicity n of the obtained paraphthaloyl acidhexamethylene diamine salt or m-phthalic acryl acidhexamethylene diamine salt is 4 to 16; (b) 6T salt or 6I salt obtained in step (a) and 66 salt or hexanolactam are polymerized to obtain primary condensation compound and the characteristic viscosity of the primary condensation compound in dense sulfuric acid is 0.09 to 0.25dl / g under the temperature of 30 DEG C; (c) the primary condensation compound obtained in step (b) is under solid phase condensation and polymerization to obtain the high-temperature nylon under the temperature of not more than 250 DEG C. The method provided by the present invention can increase the polyamide size stability, mechanic performance and heat resistance, reduce the molecular weight distribution of the high-temperature nylon, and prevent the occurrence of amine exchange, thermal degradation, gelation and other side reactions.

Description

technical field [0001] The invention relates to a method for preparing a polymer material, in particular to a method for preparing high-temperature nylon. Background technique [0002] Crystalline polyamides represented by Nylon 6, Nylon 66, and Nylon 1212 have been widely used in clothing fibers and industrial materials due to their excellent performance and melt molding processability, and are widely used as general-purpose engineering plastics. In automotive, electronic and electrical fields. However, the general-purpose polyamide has disadvantages such as insufficient heat resistance and unstable dimensions due to water absorption. Especially in recent years, polyamides used in fields such as electrical and electronic components and automobile parts have been required to have high performance. For example, with the development of surface mount technology (SMT) in the field of electrical and electronic components, polyamides need to have high heat resistance, such as re...

Claims

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Application Information

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IPC IPC(8): C08G69/28
Inventor 张西奎张怀中杨桂生
Owner 北京瑞宝知春时代印刷技术开发有限公司
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