JPS6353650B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a composite insulating tape made by laminating and integrating kraft paper on both sides of a plastic film, which is used by being wound around the conductor of a power cable.
This relates to a method of connecting a base paper roll (width 200 to 1500 mm) before slitting, or a slit tape that is being wound by a paper winding machine.

This composite insulating tape (hereinafter simply referred to as composite tape) includes, for example, polypropylene (PP),
Tape with kraft paper placed on both sides of melt extruded plastic film such as polymethylpentene (PMP) or polyethylene (PE), or tape with kraft paper placed on both sides of a plastic film such as fluorinated ethylene propylene (FEP) and kraft paper on both sides, etc. There is.

Conventionally, these composite tapes were connected to each other by a method as shown in FIG. In the figure, reference numerals 1 and 1 are composite tapes to be connected, which are made by laminating kraft paper 3 on both sides of a plastic film 2. The connection is made by butting the ends of the composite tapes 1, 1 together and pasting thin (20 to 100 μm) kraft paper 4 on both sides of the abutting portion using an adhesive. Note that thin kraft paper 4 may be pasted only on one side of the abutting portion.

However, in this method, since the connecting kraft paper 4 is pasted on the outside of the connecting portion, this portion becomes locally thick and tends to create local discontinuities in the power cable after the conductor is wound. In addition, if it becomes locally thick, that part becomes locally hard, and when it passes through various rollers just before being wound on the conductor, it cannot follow the radius of curvature of the rollers, and the connecting kraft paper 4 The disadvantage is that the tape is easily cut, causing the tape to break.

In addition, when connecting the above-mentioned base paper rolls, the thin kraft paper 4 is generally adhered to the outside of the connection part using a natural water-soluble adhesive, so that the adhesive is attached to the connecting kraft paper 4. The kraft paper of the composite tape on the outer layer or the inner layer and the connecting kraft paper 4 may get stuck together. In particular, when the kraft paper of the composite tape is moistened and used as known in Japanese Patent Publication No. 52-38237 to prevent swelling of the composite tape in oil, even if the adhesive dries initially, Even if
Over time, it absorbs moisture and softens, and eventually oozes through the connection kraft paper 4 to the outer layer or inner layer, and as mentioned above, the connection kraft paper sticks to the kraft paper of the composite tape in the outer layer or inner layer. Sometimes.

If it is plucked as described above, when the paper winding machine starts winding the conductor, the kraft paper of the outer layer or the inner layer of the composite tape will be peeled off starting at the point where it was plucked, and it will no longer look like a composite tape. There is a risk of losing it.

The present invention has been made to solve the above-mentioned problems, and by overlapping and bonding the plastic films at the end portions of composite insulating tapes to be connected, the thickness at the connection portion is locally increased. It is an object of the present invention to provide a method for connecting composite insulating tapes which has a strong connection without causing adhesive to ooze out and adversely affecting the composite tape in the outer layer or the inner layer.

The present invention relates to a method for connecting composite insulating tapes made by laminating kraft paper on both sides of a plastic film. This method of connecting composite insulating tapes is characterized in that the tapes are overlapped so that the exposed end portions of the plastic films are in contact with each other, and the overlapping inner surfaces are adhered with an adhesive.

The composite insulating tape to which the method of the present invention is applied is, as described above, a tape made by laminating kraft paper on both sides of a plastic film such as PP, PMP, PE, or FEP.

Hereinafter, the present invention will be explained by examples using the drawings.

FIGS. 2A, 2B, 2C and 2D are longitudinal sectional views of a connecting portion for explaining an embodiment of the method of the present invention, respectively. In the figure, reference numerals 1 and 1 are composite tapes to be connected, which are made by laminating kraft paper 3 on both sides of a plastic film 2.

The method shown in Fig. A is to peel off the kraft paper 3, 3 on both sides of the respective terminal parts 5, 5 of the composite tapes 1, 1, cut and remove the kraft paper 3, 3 of the same length on both sides, and remove the kraft paper 3, 3 of the same length on both sides. The plastic films 2', 2' are exposed, the exposed plastic films 2', 2' are overlapped, and the inner surfaces of this overlap are bonded together with an adhesive 6. When the kraft paper 3 of the composite tape 1 is initially peeled off, this work is easy because the adhesive strength between the kraft paper 3 and the plastic film 2 is such that it can be peeled off manually. According to this method, the thickness increase of the connection part is the least.

The method shown in FIG. Only one side of ' is exposed, the exposed surfaces are overlapped, and the overlapping inner surfaces are bonded together with an adhesive 6. According to this method, the kraft papers 3, 3 only need to be peeled off on one side from the composite tapes 1, 1, so the workability is improved, but the thickness increases by one sheet of kraft paper.

The method shown in Figure C is a modification of the method shown in Figure B.
Kraft paper 3' on the opposite side of the overlapping surface of the connection part,
The tips of the plastic films 2', 2' are cut so that the lengths of the plastic films 3' are slightly longer than the lengths of the plastic films 2', 2'. According to this method, the boundary between the plastic film 2' and the kraft paper 3 at the connection part is covered from the outside with a long kraft paper 3', so even if the adhesive oozes out from the edge of the plastic film 2', , kraft paper 3', it does not directly affect the composite tape in the outer layer or the inner layer. In this case, the increase in thickness of the bond is slightly greater than that shown in FIG. 1, but less than that of the conventional method shown in FIG.

The overlapping length of plastic films 2' and 2' in figures A, B, and C varies depending on the thickness of the composite tape, but is generally about 5 to 20 mm.
It is often selected depending on the degree.

Further, in order to prevent the adhesive 6 from overflowing from the plastic films 2', 2', it is preferable to apply the adhesive only to the central portion of the length of the overlapping surfaces, leaving a small amount at both ends. As the adhesive 6, for example, natural water-soluble rubber glue, starch glue, etc., which do not deteriorate the electrical properties after oil immersion, are inexpensive and easy to handle, are used.

The method shown in Figures A, B, and C above can be applied to both the above-mentioned base paper roll state and the slit tape state in the middle of being wound by a paper winding machine.

Also, if there is no risk of the adhesive oozing through the kraft paper 3, that is, if the composite tape is not subjected to humidity control treatment, or if the kraft paper 3 is thick compared to the amount of adhesive, the adhesive will not adhere even if the kraft paper 3 is thin. If there is enough time to dry the tape afterwards and there is no risk of smudging, or if there is no time to condition the humidity or dry it with thin paper, it will not damage the composite tape other than the connection points. For example, in the case of connecting composite tape fed out from one tape pad in the paper roll of a paper winding machine, as shown in Figure 2, the excess kraft paper 3' covered in the same way as Figure C should also be connected. , just apply adhesive 7 and stick the kraft papers 3 and 3' together. According to this method, the increase in thickness is smaller than the conventional method shown in FIG. 1, and since one end of the pasted kraft paper 3' is continuous with the kraft paper 3 of the composite tape, the connection is complete.

The method for connecting composite insulating tapes according to the present invention configured as described above has the following effects.

1. After peeling off and removing the kraft paper on at least one side of the terminals of each of the composite insulating tapes on both sides to be connected, overlap the exposed plastic film terminals of the tapes on both sides so that they are in contact with each other, and then Since it is bonded with adhesive, the local increase in thickness at the connection point is minimized, and the connection is strong.Therefore, the tape does not break when wound with a paper winding machine, and its properties are not impaired. .

2. Also, since the adhesive is applied to the inside of the plastic film, the adhesive does not ooze out to the outside of the tape connection, so it does not have an adverse effect on the composite tape on the outer layer or the inner layer.

3 In the case shown in Fig. 2 D, make the kraft paper on one side of the end of the composite tape longer than the length of the plastic film, cover the overlapping border with excess, and then glue the kraft paper together with adhesive 7. They can also be pasted together, and in this case, one end of the pasted kraft paper is continuous with the kraft paper of the composite tape, which has the effect of making the connection stronger and more complete.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a connecting portion for explaining an example of a conventional method for connecting composite insulating tapes. Second
Figures A, B, C, and D are longitudinal sectional views of a connecting portion for explaining an embodiment of the method of the present invention. 1... Composite insulation tape, 2, 2'... Plastic film, 3, 3', 4... Kraft paper, 5
...terminal part, 6,7...adhesive.

Claims (1)

[Scope of Claims] 1. In a method for connecting composite insulating tape made by laminating kraft paper on both sides of a plastic film, after peeling off and removing the kraft paper on at least one side of the terminal portions of each of the tapes on both sides to be connected. . A method for connecting composite insulating tapes, which comprises stacking the tapes on both sides so that the exposed end portions of the plastic films are in contact with each other, and bonding the inner surfaces of the stacked layers with an adhesive. 2. The method for connecting composite insulating tapes according to claim 1, wherein the peeling and removal of the kraft paper is performed on the kraft paper on both sides of the end portions of the composite insulating tapes on both sides. 3. The method for connecting composite insulating tapes according to claim 1, wherein the peeling and removal of the kraft paper is performed only on the kraft paper on the overlapping surface side of the end portion of the composite insulating tape. 4. A claim in which the kraft paper on the opposite side of the overlapping surface of the end portion of the composite insulating tape is made slightly longer than the length of the plastic film, and the long portion is overlapped and connected to the kraft paper portion of the opposing tape. A method for connecting the composite insulating tape according to item 3.