Crystalline copolymer polyimide resin low in melt viscosity and prone to melt processing and application

A polyimide resin, melt viscosity technology, used in adhesives, coatings, etc., can solve the problems of high melting point and melt viscosity, processing temperature over 400 ℃, poor melt crystallization ability, etc., to reduce processing temperature. and melt viscosity, excellent melt crystallinity, easy melt processing effect

Active Publication Date: 2016-11-30
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, there are very few polyimide resins with both crystallinity and melt processability, mainly because the prior art mainly has the following disadvantages: (1) the rigid structure of the molecular chain of polyimide and the strong interaction between molecules lead to its melting point And the melt viscosity is too high, the processing temperature often exceeds 400°C, and the processing is difficult
(2) Most crystalline polyimides lose or greatly reduce their crystallization ability after melting, and the parts cannot show high temperature resistance
(3) Even if a small number of polyimides still show crystallization ability after melting, their crystallization rate is very slow, and the parts need to undergo a long period of high-temperature post-treatment to show crystallinity
However, the crystallization ability of the polymer melt is poor, and it is necessary to add a low-molecular nucleating agent or carbon nanofiller as a nucleating agent to show repeated crystallinity, and cannot be used directly as a crystalline resin.
At the same time, in order to obtain crystalline polyimide with a lower melting point and a higher glass transition temperature in the above-mentioned documents, monomers with low versatility, difficulty in synthesis, and high specificity have to be used, resulting in higher raw material costs and difficult Realize mass production and form products with market competitiveness
[0008] In summary, in the prior art, most of the crystalline polyimides with a glass transition temperature greater than 190°C and a melting point lower than 385°C with a fully aromatic structure have the disadvantages of poor melt crystallization ability and high melt viscosity

Method used

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  • Crystalline copolymer polyimide resin low in melt viscosity and prone to melt processing and application
  • Crystalline copolymer polyimide resin low in melt viscosity and prone to melt processing and application
  • Crystalline copolymer polyimide resin low in melt viscosity and prone to melt processing and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] Add 14.6165g (50.0mmol) TPER, 2.8966g (7.2mmol) 3,3',4,4'-triphenylene ether tetracarboxylic dianhydride to a three-necked flask equipped with a stirrer, reflux condenser and nitrogen gas guide tube (referred to as HQDPA), 12.0042g (40.8mmol) BPDA, 0.5925g (4.0mmol) PA, 180g m-cresol, 10 drops of isoquinoline, react under nitrogen atmosphere, stir evenly, heat up to 200°C for 8 hours , cooled to room temperature, adding ethanol as a precipitant, the polymer was precipitated in powder form, washed with a large amount of ethanol and water, and then dried in a vacuum oven at 150° C. for 10 hours to obtain polyimide resin PI-1.

[0056] The inherent viscosity of PI-1 measured by an Ubbelohde viscometer in a m-cresol solution with a concentration of 0.5 g / dL at 30° C. is 0.51 dL / g.

[0057] The X-ray powder diffraction pattern of the polymer is shown in figure 1 As shown, it has the sharp characteristic diffraction peaks of crystalline polymers (with high crystallinity).

...

Embodiment 2

[0061] Add 14.6165g (50.0mmol) TPER, 1.9311g (4.8mmol) HQDPA, 12.7103g (43.2mmol) BPDA, 0.5925g (4.0mmol) PA, 180g m-cresol, 10 drops of isoquinoline, react under nitrogen atmosphere, stir evenly, heat up to 200 ° C for 8 hours, cool to room temperature, add ethanol as a precipitant, the polymer is precipitated in powder form, use a large amount of ethanol and washed with water, and then dried in a vacuum oven at 150° C. for 10 hours to obtain polyimide resin PI-2.

[0062] The obtained PI-2 was measured by DSC, as a result, only the melting point T was observed in the first heating curve m is 376°C, no clear observation of Tg and T c (with a high degree of crystallinity). T is observed in the second warming g 193°C, T m It is 378°C. Its 5% thermal decomposition temperature in air is measured to be 543°C. The inherent viscosity is 0.60dL / g. The melt complex viscosity measured by rotational rheometer is 1240 Pa·s (at 423° C.).

Embodiment 3

[0064] Add 14.6165g (50.0mmol) TPER, 3.8622g (9.6mmol) HQDPA, 11.2980g (38.4mmol) BPDA, 0.5925g (4.0mmol) PA, 180g m-cresol, 10 drops of isoquinoline, react under nitrogen atmosphere, stir evenly, heat up to 200 ° C for 8 hours, cool to room temperature, add ethanol as a precipitant, the polymer is precipitated in powder form, use a large amount of ethanol and washed with water, and then dried in a vacuum oven at 150° C. for 10 hours to obtain polyimide resin PI-3.

[0065] The obtained PI-3 was measured by DSC, as a result, only the melting point T was observed in the first heating curve m is 358°C, no clear observation of T g and T c (with a high degree of crystallinity). T is observed in the second warming g 191°C, T m It is 356°C. Its 5% thermal decomposition temperature in air is measured to be 546° C., and the inherent viscosity is 0.55 dL / g. The melt complex viscosity measured by rotational rheometer is 750 Pa·s (at 417° C.).

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Abstract

The invention discloses crystalline copolymer polyimide resin low in melt viscosity and prone to melt processing. The crystalline copolymer polyimide resin is prepared from aromatic dianhydride monomers, aromatic diamine monomers and capping agent by means of condensation polymerization, mixtures of 3,3',4,4'-triphenyldiether tetracarboxylic acid dianhydride and other dianhydrides are taken as aromatic dianhydride monomers, and phthalic anhydride is taken as capping agent. The copolymer polyimide resin has high glass transition temperature, good heat stability, low melt viscosity, excellent repeated melt crystallization capacity and easy-melting processability, the melting range is 320-380 DEG C, and the polymer has broad application in preparation of materials such as composite material matrix resin, high-temperature adhesives, powder coating, high-performance films, 3D-printing polymer powder and the like.

Description

technical field [0001] The invention relates to a polyimide resin, in particular to a crystalline copolymerized polyimide resin with low melt viscosity and excellent melt repeated crystallization ability and its application. Background technique [0002] Polyimide resin is currently one of the highest heat-resistant polymer materials in industrial practical applications. Due to its comprehensive properties such as high thermal stability, solvent resistance, high mechanical strength, excellent insulation, and radiation resistance, it has been Widely used in aerospace, mechanization, electrical and electronic fields. Due to the rigid molecular chain and the strong interaction force between molecules, polyimide is difficult to dissolve and melt. Therefore, most polyimide resins can only be processed by solution molding and hot pressing, and cannot be used in engineering. Extrusion and injection molding (hereinafter referred to as melt processing) are commonly used in plastics....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G73/10C08L79/08C09D179/08C09J179/08
CPCC08G73/1014C08G73/1071C08L79/08C09D179/08C09J179/08
Inventor 方省众张鸿飞王玮陈国飞
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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