RU2004554C1 - Prepreg - Google Patents

Abstract

Usage: insulating parts of electrical machines. The inventive prepreg on the basis of fiberglass, mica paper and a binder, in the following ratio of components, wt.% 1 epoxy resin based on polyphenol 25 - 33, epoxy Dianova resin 8 - 13.5, 50% solution of a complex of boron trifluoride (BF) with monoethanolamine in diethylene glycol 0.9 - T, 75. thermoplastic polymer from the group: polyvinyl-cetapi, polystyrene, copolymer of styrene with acrylonitrile and styrene with acrylonitrile and butadiene rubber 0.4 - 0.9, mica on paper and fiberglass in the ratio -1.3 - 2.61 1 rest. 3 tab.

Description

The invention relates to the field of electrical engineering, in particular to the production of pre-impregnated materials (prepregs) for insulating parts of electrical machines

Insulating prepregs based on fiberglass and mica-containing materials, e.g., based on fiberglass and mica with a thermosetting binder, are known. A prepreg based on a polyester support fabric with micanite and a binder containing an epoxy resin and diaminodiphenylsulfone as a hardener is also known. The use of a solvent-free binder allows this prepreg to be made without air inclusions, but it requires the application of mica powder after impregnation to prevent sticking, which creates significant technological difficulties and increases labor intensity.

The closest technical solution to the proposed prepreg, taken as a prototype, is a prepreg made of fiberglass, mica paper and an epoxy binder containing epoxynolac resin (polyfunctional epoxy resin based on polyphenol) and a complex of boron trifluoride (BP3) with amines as a hardener . This prepreg is used in the form of a tape to insulate the winding rods of large electrical machines. This insulation has the advantages of high heat resistance and good electrical insulation characteristics.

The disadvantage of this prepreg is the use of imported hardener for its manufacture in connection with certain difficulties in its manufacture in our country, the greater rigidity of isolation from it, which leads to significant internal stresses, delamination from copper and delamination; poor maintainability due to poor softening of the pressed material at the applied heating temperatures; relatively short shelf life (3 months in sealed packaging) and the need to heat the prepreg tape when it is applied to the rod, etc. The purpose of the invention is to improve the prepreg processability and increase the adhesion of the prepreg insulation to copper and its maintainability.

This goal is achieved in that in a prepreg based on fiberglass, mica paper and a binder comprising an epoxy resin based on polyphenol and a complex of boron trifluoride (BP3) with amines, the binder further comprises an epoxy resin in a ratio of 1: 1.85-4 with polyphenol-based epoxy and

a thermoplastic polymer selected from the group consisting of polyvinyl acetate, polystyrene, its copolymers with acrylonitrile and butadiene rubber, as a complex of boron trifluoride (BP3) with amines, the prepreg contains BP3 with monoethanolamine in the form of a 50% solution in diethylene glycol, on paper and fiberglass were taken in a ratio of 1.3 -2.61: 1 in the following ratio of the components of the pregre. wt.%:

Polyphenol Based Epoxy 25-33

Epoxy Dianova 5 resin 8-13.5

50% solution of the complex of BP3 with monoethanolamine in diethylene glycol 0.9-1.75

0 Thermoplastic polymer 0.4-0.9 Mica on paper and fiberglass in a ratio of 1.3-2.61: 1 Other 5 The composition of the prepregs, their properties and the properties of the insulation pressed from the prepreg are shown in Tables 1 and 2, and the varnish formulation for the manufacture of these prepregs is shown in Table 3.

0 As can be seen from Table 2, the proposed prepreg is highly adaptable, flexible at room temperature and retains elasticity over a long shelf life that exceeds the shelf life of the prepreg according to the prototype. Isolation from the prepreg has high adhesion to copper and high deformation heat resistance, providing high mechanical strength of the insulation at 0 temperature up to 155 ° C.

The prepreg is made as follows.

A solution is prepared from epoxy resins in a solvent mixture of toluene: butanol: acetone 3: 1: 2; 5, a solution of 50% in diethylene glycol of boron trifluoride complex (BP3) with monoethanolamine and a solution in a small part of the solvent are added thereto 0 thermoplastic polymer. Fiberglass is impregnated with finished varnish on a horizontal impregnation machine, its duplicate in the process of impregnation with mica paper. From the obtained prepregs, the isolation according to 5 conditions is pressed:

Temperature 160 ± 5 ° С

Specific pressure 1 MPa

Compression time 5 h. PRI me R 1. In the mixer load of 18.4 kg of toluene, 6.1 kg of butanol and 6.1 kg

acetone. 45.25 kg of ETF resin are heated to a temperature of 130 ° C, gradually, with the stirrer turned on, loaded into a mixer with solvents and dissolved by stirring for 12 hours. 15.10 kg of ED-16 resin are heated to 60 ° C and introduced into the mixer with solvents and ETF resin and dissolved with stirring for 4 hours.

0.95 kg of acetone was charged into a separate container and kept under periodic stirring until completely dissolved. Then 1.90 kg of UP-605 / 4P hardener is poured into this container, thoroughly mixed until homogeneous, and the resulting solution is poured into the mixer with dissolved resins with stirring. A light brown varnish is obtained with a viscosity according to B374 at 20 ° С for 20 s and a solids content of about 63%.

This varnish on a horizontal impregnation machine is impregnated with fiberglass grade ЭЧ-46 and duplicate it after leaving the bath with mica paper grade SB-86. The prepreg was dried in the chamber of the machine at a temperature of 100 + 5 ° C for 8 minutes. A prepreg is obtained with a total content of fiberglass and mica paper of 59.8 wt.%, A binder of 40.2 wt.%, Wound into a roll on a receiving mandrel. The roll is cut into 25 mm wide rollers. The tape is applied to the rod with a cross-section of 15x50 mm full overlap with the required number of layers and pressed at a temperature of 160 ° C and a pressure of 1 MPa for 5 hours. The obtained insulation is subjected to the necessary tests.

PRI me R 2. According to the technology described in example 1, varnish is prepared from 13.65 kg of ED-16 resin, 40.8 kg of UP-643 resin, 1.45 kg of UP-605 / 4P hardener 0.65 kg of polystyrene, 21.7 kg of toluene, 7.2 kg of butanol and 14.5 kg of acetone. Varnish is a homogeneous light brown liquid with a viscosity of VZ-4 - 19 s and a solids content of about 50%. Analogously to Example 1, an impregnated material is obtained with a content of fiberglass and mica paper of 65.3 wt.%, And a binder of 34.7 wt.%. From this prepreg, according to the technology and modes described in Example 1, isolation for testing is prepared.

Examples 3-7. According to the technology described in Example 1, varnishes are prepared in accordance with their formulation given in Table 3. Varnishes of different shades of brown with a viscosity of VZ-4 20-22 s and a solids content of 63-70 wt.%. Impregnation with these varnishes as described in

Example 1 of a glass fabric with micaceous paper technology produces prepregs that differ in component content. From these prepregs, isolation for testing is prepared using the above technology and mode.

The prepreg in Examples 1-5 is technologically advanced: it does not stick together and is elastic at room temperature for a long shelf life, and the insulation from it has high adhesion to copper, monolithicity and deformation heat resistance, providing high mechanical strength at temperatures up to 155 ° C.

When the content of the components is below the minimum values of the formula (Example 6), the adhesion strength of the prepreg increases, and when unwinding the roll (roller), mica paper is destroyed.

If the content of the components is higher than the maximum values of the formula (Example 7), a prepreg is obtained with a not very long storage time and isolation from the prepreg with low electric strength due to the low content of mica paper and the high dielectric loss tangent due to the increased content of the thermoplastic polymer.

The proposed prepreg can significantly improve the manufacturing process of winding large electrical machines. This reduces labor intensity and energy consumption by eliminating heating of the tape before winding.

An increase in the shelf life under normal conditions ensures the preservation of good technological properties at no additional cost, and an improvement in the maintainability of the insulation from the prepreg will reduce production losses associated with the inevitable rejection of part of the products during operational tests. High quality prepreg insulation will increase the reliability and durability of the machines.

The proposed prepreg can be made at any enterprise manufacturing pre-impregnated materials on existing equipment. No additional time is required to bring it to industrial use.

(56) German Patent No. 2421527, cl. C 08 I 5/24, 1976.

U.S. Patent No. 4,606,785. C 08 I 5/04. 1986.

USSR author's certificate N 1045803, cl. C 08 I5 / 24. 1980.

Table 1

table 2

Extension of Table 2

Table 3

Claims (1)

The claims PREPREG based on fiberglass, mica paper and a binder comprising an epoxy resin based on polyphenol and a complex of boron trifluoride (BP3) with amines, characterized in that, in order to improve the processability of the prepreg and increase the adhesion of the insulation from the prepreg to copper and its maintainability, the binder additionally contains an epoxy diamine resin in a ratio of 1: 1.85 - 4 with an epoxy resin based on polyphenol and a thermoplastic polymer selected from the group consisting of polyvinyl acetals, polystyrene, its copolymers with acrylonitrile scrap and butadiene rubber, as a complex with amines SAS prepreg 0 contains BP3 with monoethanolamine in the form of a 50% solution in diethylene glycol, and mica on paper and fiberglass was taken in a ratio of 1.3 - 2.61: 1 in the following ratio of prepreg components, wt.%: 1 Epoxy based polyphenol Epoxy Dianova Resin 50% Complex Solution boron trifluoride (BP3) with monoethanolamine in diethylene glycol Thermoplastic polymer Mica on paper and fiberglass in a ratio of 1.3 - 2.61: 1 25-33 8-13.5 0.9-1.75 0.4-0.9 Rest