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Preparation method of polyimide fiber insulating paper

A polyimide fiber and insulating paper technology, which is applied in the direction of insulators, organic insulators, plastic/resin/wax insulators, etc., can solve the problem of large linear expansion coefficient of polytetrafluoroethylene powder, poor product dimensional stability, and large linear expansion coefficient and other problems, to achieve the effect of low cost, excellent performance and good flame retardancy

Inactive Publication Date: 2012-07-18
TIANJIN POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although PTFE powder has the advantages of strong corrosion resistance, good heat resistance and excellent electrical properties, it also has many disadvantages, such as poor radiation resistance, non-stickiness, and large linear expansion coefficient. Ethylene powder is non-sticky, adding it to polyimide fibers will cause problems such as surface defects and delamination in the prepared paper, and the linear expansion coefficient of polytetrafluoroethylene powder is large, which will increase with the Very irregular changes occur due to temperature changes, and the material will undergo large deformation during the hot rolling process, resulting in poor dimensional stability and poor quality of the product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] (1) Web making: select polyimide fibers with a length of 20mm and a fineness of 0.7dtex, open and card them conventionally, and cross-lay at 90° vertically and horizontally to obtain a polyimide fiber web;

[0027] (2) Chemical bonding and drying process: dissolve the polyamic acid resin in the solvent DMF and stir for 30 minutes to obtain a polyamic acid adhesive solution with a volume concentration of 30%, and then impregnate the fiber web in the prepared In the binder solution, soak for 30min, and the squeeze rate is 100%; finally, dry the prepared wet fiber web in an oven at 110°C for 1.5h;

[0028] (3) Compression molding: The dried fiber web is molded by a molding machine to obtain insulating paper; the molding process parameters are: molding temperature 150°C, molding pressure 25Mpa, molding time 90min.

[0029] After inspection, the insulating paper weighs 48g / m 2 , thickness 0.05mm, longitudinal tensile strength 120N / 15mm, transverse tensile strength 100N / 15mm...

Embodiment 2

[0031] (1) Net making: select polyimide fibers with a length of 78 mm and a denier of 1.5 dtex, open and card them conventionally, and cross-lay at 90° vertically and horizontally to obtain a polyimide fiber web;

[0032] (2) Chemical bonding and drying process: dissolve the polyamic acid resin in the solvent DMAc and stir for 30 minutes to obtain a polyamic acid adhesive solution with a volume concentration of 0.3%, and then impregnate the fiber web in the prepared In the binder solution, soak for 25min, and the squeeze rate is 300%; finally, dry the prepared wet fiber web in an oven at 40°C for 6h;

[0033] (3) Compression molding: The dried fiber web is molded by a molding machine to obtain insulating paper; the molding process parameters are: molding temperature 350°C, molding pressure 2Mpa, molding time 30min.

[0034] After inspection, the insulating paper weighs 190g / m 2 , thickness 0.18mm, longitudinal tensile strength 143N / 15mm, transverse tensile strength 121N / 15mm,...

Embodiment 3

[0036] (1) Net making: select polyimide fibers with a length of 45mm and a fineness of 2.0dtex, open and card them conventionally, and cross-lay at 90° vertically and horizontally to obtain a polyimide fiber web;

[0037] (2) Chemical bonding and drying process: Dissolve the polyamic acid resin in the solvent NMP and stir for 30 minutes to obtain a polyamic acid adhesive solution with a volume concentration of 12%, and then impregnate the fiber web in the prepared In the binder solution, soak for 10 minutes, the squeeze rate is 135%, and finally dry the prepared wet fiber web in an oven at 90°C for 2.2 hours;

[0038] (3) Compression molding: The dried fiber web is molded by a molding machine to obtain insulating paper; the molding process parameters are: molding temperature 220°C, molding pressure 20Mpa, molding time 50min.

[0039] After inspection, the insulating paper weighs 100g / m 2 , thickness 0.15mm, longitudinal tensile strength 158N / 15mm, transverse tensile strength ...

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Abstract

The invention discloses a preparation method of polyimide fiber insulating paper. The preparation method comprises the following steps of: adopting a polyimide fiber with a length of 20-78 mm and a fiber number of 0.7-8.0 dtex as a raw material, and obtaining a polyimide fiber net through conventional opening, carding and lapping; and then, impregnating the fiber net into a polyamic acid adhesive solution for 10-30 minutes, passing the fiber net through a mangle with a mangle expression of 100-300%, and then, drying the fiber net, and finally, preparing the polyimide fiber insulating paper through a mould pressing process, wherein the adhesive solution is prepared from polyamic acid resin with the same components as the polyimide fiber and a solvent according to a requirement that the volume concentration is 0.3-30%; the solvent is selected from one or two of DMF (dimethyl formamide), DMAc (dimethyl acetamide ) and NMP (N-methyl pyrrolidone) mixed in any proportion; the drying temperature is 40-130 DEG C and the drying time is 0.5-6 hours; and the mould pressing process is that the mould pressing temperature is 150-350 DEG C, the mould pressing pressure is 2-25 MPa, and the mould pressing time is 5-90 minutes.

Description

technical field [0001] The invention relates to an insulating material preparation technology, in particular to a preparation method of polyimide fiber insulating paper. The insulating paper is mainly used for insulation between slots and layers of high-frequency special transformers, high-voltage high-frequency transformers, hydroelectric generators and other equipment. Background technique [0002] Insulating paper is widely used as insulating materials for electrical equipment (generators, transformers, etc.), household appliances, electric tools and other equipment, and is also the main component material of insulating materials such as laminated products, composite materials and prepreg materials. Due to the special use of insulating paper, it is required to have some characteristics different from other paper types, mainly including mechanical properties, electrical properties and thermal stability. And because all kinds of electrical equipment are used in different e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21H27/12
Inventor 焦晓宁程博闻李书干庄旭品
Owner TIANJIN POLYTECHNIC UNIV
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