SU1282222A1 - Cementing thermoplastic composition for enameled-insulated wires - Google Patents

Description

The invention relates to adhesive formulations intended to bend the glueing of enamelled wires of thin and thinnest sections. These compositions are applied directly to the polyurethane insulation using a combined technology at one technological reception at temperatures of 350-450 C and speeds of 230-250 m / min. The presence of an adhesive thermoplastic layer on enamelled wires allows to produce glued monolithic frameless coils or windings directly into pro. process of their winding by heat treatment.

The purpose of the invention is to reduce the temperature of bonding wires, as well as g

same improvement of the technological properties of the composition of

PA of FIG. 1 is a scheme for determining the deformation of the samples in FIG. 2, the graphs of the dependence of the deformation on temperature.

A three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser is placed into the calculated amount of the dimethiolformam-shcha and the mixer turned on and the polyvinyl butyral is loaded in portions. Include heating. Sodershmy flasks are heated to 100 ° C with stirring and thermoplastic polyurethane is charged. Heating and stirring are continued until the loaded components are completely dissolved. Then the solution is filtered. Ready The composition has a content of non-volatile substances of 10-11 wt.% (1 g, 1 h LL: 150 C) and a viscosity using a BZ-4 viscometer at 20 C - 20-30 s. According to the proposed scheme, compositions 1-3, given in E table, are prepared. one.

The resulting adhesives 1-3 ,. as well as the original polywingbutnral and thermoplastic polyurethane is subjected to licnLiTaHHHM to change the deformation when heated. For this purpose, the adhesive compositions and solutions of polyvinyl butyral and thermoplastic polyurethane are dipped onto samples of copper strap with a diameter of 1 and a length of 280 mm and dried at 150 ° C for 0.5 h. Each sample of wire, previously bent in half, is laid between metal plates 1 of the device (fit 1) for testing the deformation in such a way that

0

with

each subsequent sample is perpendicular to the previous one (crosswise). Just take 14-16 samples 2 (figure 1). The plates are compressed with a load of 4350 g. The device is placed in a thermostat and the position of the upper plate h is fixed. indicator micrometer. Thermostat include. As the thermostat is heated, the position of the top plate b is fixed with an indicator micrometer. The value of the deformation D is determined by the formula

h, - bi

five

D 100%

n b

where n is the number of samples

b is the average diametral thickness of the adhesive layer, mm. As a result of the test, 0 curves of the deformation of the adhesive coating on temperature are obtained. The inflection of the curves corresponds to the temperatures of softening the surface (transition to a viscous-fluid state). The curve of deformation for polyvinyl butyral, the temperature of its bending of 140-150 C (the temperature of melting according to the method of a ring and a ball is 150 C) has the form of a curve 3 of figure 2. For thermal polyurethane, the bend of the curve lies in the region of 180-190 ° (curve 4 of FIG. 2). As can be seen from Fig. 2, the introduction of thermoplastic polyurethane into the adhesive composition based on polyvinyl butyl leads to the effect of lowering the softening temperature of the adhesive coating: for composition 1 (table 1) the curve bends the temperature (curve 5 of figure 2) , for compounds 2 and 3, respectively, 123 and (curves 6 and 7 of FIG. 2). This allows you to firmly glue.

0

insert wires in the process of winding products at 150-170 0 for 1-3 s. When thermoplastic polyurethane polyurethane is introduced into the adhesive composition on the basis of polyvinyl butyral in an amount of more than 2.5 wt.%, The adhesiveness of the adhesive layer appears under normal conditions during storage of the enamelled wire.

50

Reduced thermoplastic content

polyurethane in the adhesive composition below 1.5 wt.% practically does not lead to a decrease in the softening temperature of the adhesive coating and, accordingly, to an increase in the bonding strength of the wires under these conditions.

In tab. 2 shows data on the properties of enamelled wires of diameter 3

rum O, 02 MM with basic polyurethane; adhesive insulation and adhesive layer based on adhesive compositions according to the formulations of compositions 1-3 according to the table. 1 and in comparison with the known.

As can be seen from the table. 2, the adhesive wires obtained using the proposed adhesive compositions are well serviced at 375i5 ° C for 1-3 seconds. have greater bonding strength of the turns of wires when winding products than wires made using a known composition.

The proposed adhesive compositions are more technological: the required thickness of the adhesive layer on the wire is obtained in fewer passes.

Thus, the use of the proposed adhesive compositions for bonding enameled wires leads to a decrease in the temperature of the adhesive.

And, respectively, to increase the strength of bonding the wires at 150-170 ° C. The resulting bonding wires are maintained without first stripping the insulation. Adhesives are easy to apply, and they are applied to enameled wires with polyurethane insulation using a combination of techniques adopted for applying a polyurethane coating with a small number of passes, which leads to an increase in labor productivity in the manufacture of bonding wires.

The use of adhesive bonding wires made using the proposed adhesive compositions in the manufacture of electric coils makes it possible to eliminate the stage of impregnation of the coils in order to give them solidity to increase the productivity of labor during their manufacture, to obtain energy savings.

Table 1

Polyvinyl butyl

Thermoplastic

Coating thickness, mm with the number of passes

Service at (375i5) C, 1-3 p.

Creep strength factor (at 170 ° С, 5 min)

7.5

8.5

8.5

Table

2.2-2.4 2.2-2.4 2.2-2.4 1.5-1.7

804

 | ..,

I

20

60

80

J.

 iSD 7 Temgeregursg, ° C

Claims (1)

ADHESIVE THERMOPLASTIC COMPOSITION FOR ENAMELED WIRES, containing polyvinyl butyral and an organic solvent, characterized in that, in order to reduce the bonding temperature of the wires, as well as improve the technological properties of the composition, it additionally contains (thermoplastic polyurethane with a softening temperature of 180-190 ° С on based on polyfurite with a molecular weight of 1500-2000, 4,4 * -diphenylmethanedipzocyanate and .1,4-butanediol, and dimethyl formamide as the organic solvent, with the following components, wt. £: Polyvinyl butyral. Thermoplastic polyurethane dimethylformamide ratio 7.5-8, ¾ 1.5-2.5 Rest Fig i SLL „„ 1282222 A1 1282222 2