CS215265B1 - Method of creating electrical insulation especially for dynamo-sheets - Google Patents

Abstract

The invention relates to a method for forming electroinsulating coatings on dynamo sheets. The method uses a waste product resulting from the production of pulp from beech wood by the sulphate method with aqueous pre-hydrolysis. This waste product diluted with water at a concentration of 30 to 35% (on dry matter) is applied to the dynamo sheet strip using a system of rubber-coated rollers and the applied layer is subjected to the effect of an elevated temperature in the range of 300 to 370 °C for 20-30 seconds. A continuous solid coating with high electroinsulating resistance is obtained. Compared to the methods used so far using other starting materials, the proposed solution is economically more advantageous and in some cases also has higher utility properties. Properties of the obtained coating: Specific insulation resistance 3.9 . 1012Ω . cm Insulation resistance min. 20fj/cm2 High adhesion Temperature stability up to 200 °C Increased resistance to water and atmospheric corrosion.

Description

The present invention relates to a process for the formation of electrolytic coatings for dynamo sheets. The method utilizes a waste product used in the production of pulp from beech wood by the sulphate process with aqueous pre-hydrolysis. This waste product, diluted with water at a concentration of 30-35% (on dry weight), is applied to a sheet of dynamo sheet with the aid of a set of rubberized rollers and the applied layer is subjected to an elevated temperature in the range 300-370 ° C for 20-30 seconds. A continuous solid coating with a high electroisolation resistance is obtained.

The proposed solution is economically more advantageous and, in some cases, also has higher utility properties compared to the method used by other starting materials.

Properties of the obtained coating:

3.9. 1012Ω. cm · 20Q / cm ²

200 ° C.

Insulation resistance Insulation resistance min. High adhesion Temperature stability to

Increased resistance to water and atmospheric corrosion].

1 5 2 6 N

The present invention relates to a method of producing and isolating this insulation, in particular, to the use of waste products in the production of pulp from beech wood.

For the isolation of electrotecitics 'coatings' used 'coatings' hurt predominantly of inorganic origin on the basis of cobalt phosphate, alkaline earth phosphates, respectively. silicon and magnesium oxide. Abroad, this situation persists, while the materials and technologies developed are inaccessible and little published mainly for license reasons, which is noticeably especially in dynamoplechlech. Coatings of organic origin have been dominant in the last decade because they are relatively cheaper raw materials and mainly have more suitable technological properties, especially in the processing and isolation of dynamo sheets, such as easier cutting of the sowing, several times longer tool life. and the grip itself! coating at deposition and later processing. So far, polyamide and enamel lacquers and phenol-formaldehyde resins are used. These drawbacks are mainly due to the fact that, in addition to the relatively high cost of the raw material, they cause damage to the coating during firing of the coating. The coatings based on sulphite stillage of more or less descharged sugars to which phosphoric acid is used are used, for example, in US Pat. 899523, respectively. in MS. U.S. Patent No. 5,768,516; 112 474. However, these coatings exhibit relatively low electrical insulating properties, in particular they do not resist the effect of water and humid environments during their use. '·

The above-mentioned drawbacks have been eliminated and the problem has been solved by a method of forming electrical insulation, in particular on dynamo-plates according to the invention, which consists in applying to both dynamo-plates a 30-35% solution of waste product . The web coated with dynamo · the solution is evaporated at pH-phenyl 300-370 ^'C: MB for 20 to 30 seconds. .

The advantages of the invention to the state of the art in the world are, in addition to the inexpensive nature and the substantially lower price. The raw materials have high insulating resistance and corrosion resistance in achieving high Insulated insulation properties. It does not require ingestion of · acid-binding agents, In the case of stillage stillage, precipitation of inorganic substances has to be effected with the necessity to remove by sedimentation or filtration. In addition, the ease of preparation of the coating solution does not lead to the formation and release of harmful pollutants. An embodiment of the method according to the invention:

The waste product used was produced in the production of beech pulp by the manufacturer's Xylocel brand, containing 50% xytose, 6% ash, and 45 g / l organic acids in the dry matter and reaching a density of 30 ° Be. Before application to the sheet, the dry matter is diluted with water to a concentration of 30 to 35% and such a solution is applied to the waist in a continuous line by means of a set of rubberized rollers with a thrust pressure and further heated until fired in caulking care to 350 °. C at a heating time of 28 seconds. The invention can be used in the coating of coatings. Other products · Designed for electrical purposes.

Electrotechnical insulators applied on both sides to a dynamo plate in the same manner on a continuous line. coating thickness 2 to maximum ··· 5 · m. 10-6 dark brown: insulation resistance of at least 20 ý / cm2 measured by flat electrode · contact · flat surface 1 m m? hard chromium plated at a pressure of 150 kN according to technical conditions No 205/72 c72 / 72; the coating is resistant to atmospheric-corrosion and water.

Claims (2)

OBJECT OF THE WORKING OF ELECTRICAL INSULATING MACHINES, IN PARTICULAR, A 30-35 ° W WATER PRODUCT WILL BE APPLIED ON THE SIDE OF THE TEMPERATURE SHEET WITH THE WATERPROOF OF THEM, with sputter deposition Dissolve at 300 to 370 ° C for 20 to 30 seconds. 2 1 5 2 6 5 JCT 5 5129-3 85