JPS6011619B2 - Manufacturing method of laminated paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in a laminated paper and a method for producing the same, and particularly to a laminated paper suitable for insulating paper for ultra-super high voltage cables and a method for producing the same.

Recently, synthetic paper has been considered as an alternative to kraft insulating paper as an insulating material for ultra-high voltage cables. This synthetic paper is made by processing plastic fibers into a paper-like shape, and has the advantages of being breathable in the thickness direction and having lower dielectric loss than kraft paper. When this happens, wrinkles tend to occur, and polyolefin materials with low yield loss have the disadvantage of poor oil resistance. Furthermore, plastic fibers have a single thickness compared to natural cellulose fibers, and have the disadvantage that even when the density is increased, both the AC breakdown value and the impulse breakdown value are low.

For this reason, the use of laminated paper (PD laminated paper), which is made by laminating two sheets of kraft paper on top and bottom with a polypropylene film in between, is being considered, but polypropylene dissolves slightly in OF cable oil. It has swelling properties, and its adhesion to kraft paper is not always sufficient, causing peeling in heated oil and causing wrinkles and buckling at offset and snake parts of cables. There was a risk that this would happen.

The present invention was made in order to solve the above-mentioned drawbacks of conventional methods, and consists of laminating a softened silicone-grafted polyolefin film extruded by an inflation method and cellulose paper having alcoholic OH groups. The object of the present invention is to provide a method for producing laminated paper, which comprises fusing the two together under pressure, and then crosslinking a silicone-grafted polyolefin film in the presence of a silanol condensation catalyst.

The silicone-grafted polyolefin used in the present invention is preferably a polyolefin such as high density, medium density or low density polyethylene or polypropylene, and a radical generator such as dicumyl peroxide (DCP).
．． 01-2. and vinyltrimethoxysilane (V
TMOS) and pinyltriethoxysilane (VTEOS)
A compound having a hydrolyzable silyl group such as 0.
1-5. % by weight, and co-feeding this to a device having a heating crosstalk function such as an extruder,
It is obtained by heat exposure at about 20 mm. At the stage when most of the silane compound has reacted, this silicone-grafted polyolefin is pelletized. A masterbatch containing a silanol condensation catalyst such as dibutyltin dilaurate or dibutyltin diacetate is added to the silicone-grafted polyolefin isoveret thus obtained, and the mixture is formed into a film by an inflation method.

The silanol condensation catalyst may be added to the polyolefin together with the silane compound, a radical generator, etc. prior to the grafting reaction of the silane compound, or it may be added to the polyolefin after it is formed into a film and then allowed to penetrate through the surface of the film. Good too.

The details will be explained below with reference to FIGS. 1 and 2. The silicone-grafted polyolefin tube 3 containing the silanol condensation catalyst extruded from the head 2 of the extruder 1 is made of air that is introduced into the tube. It is expanded by pressure and stretched to a thickness of about 5 to 150 ridges.

4 is a roll for sealing the air inside the tube. The film thus stretched is then cut open in the longitudinal direction by a cutter 5. This film is then coated with kraft insulating paper 7, which is continuously fed out at the same speed as the film via guide rolls 6, 6'.
7' are placed along both sides and are pressed together by a pressure roll 8 heated to 40 to 100°C to fuse them together.
The laminate tape 9 obtained in this way has a silicone-grafted polyolefin film that is crosslinked in the presence of collected moisture, and at the same time reacts with the alcoholic PH groups in the kraft insulating paper to form strong chemical bonds. do. In the above embodiments, the cylindrical film was cut open and laminated with the graft insulating paper, but the cylindrical film may be crimped as is and used as a single film. In this case, if the film is pressed in advance through a heated roll, the temperature of the pressure roll 8 will be 40°C.
The temperature of the pressure roll may be 100 DEG C. to 20 DEG C., but when the film is pressed and the kraft insulating paper is laminated at the same time, the temperature of the pressure roll is preferably 100 DEG to 20 DEG C. Furthermore, the silanol condensation catalyst does not need to be blended into the film in advance; for example, it can be impregnated into kraft insulating paper, and when the film and this kraft silk paper are laminated together, the silanol condensation catalyst can be used as an insulator. The film hesilanol condensation catalyst may be transferred from the paper. The laminated paper thus obtained has excellent oil resistance properties because the silicone-grafted polyolefin is crosslinked, and in particular, some of the hydrolyzable silyl groups in the silicone-grafted polyolefin film are crosslinked. Because it reacts directly with the alcoholic OH groups of Raft Zetsuyakusei, it exhibits excellent peel strength.

In addition, since the L-silicone grafted polyolefin film is extruded using the inflation method, the thickness of the film can be reduced to about 10 mm, and the resulting laminate tape can be used as thin paper on cable conductors or as insulation for capacitors. It can be advantageously used as paper, Zetsukata lacquer paper for wire winding, etc.

Furthermore, when the inflation method is used, the stretching ratio of the film is increased and the degree of crystallinity is improved, which, together with the effect of crosslinking, makes it possible to obtain a laminated insulating paper with excellent oil resistance.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing an embodiment of the present invention.
FIG. 2 is a perspective view showing the main parts of FIG. 1; 1... Extruder, 2... Head, 4... Roll, 5... Cutter,
7, 7'...Kraft insulating paper, 8...Pressure roll,
9... Laminating tape. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A silicone-grafted polyolefin film in a softened state extruded by an inflation method and cellulose paper having an alcoholic OH group are laminated and pressurized to fuse them together, A method for producing a laminated paper, which comprises subsequently crosslinking a silicone-grafted polyolefin film in the presence of a silanol condensation catalyst. 2. The method for producing laminated paper according to claim 1, wherein the silanol condensation catalyst is added to silicone-grafted polyolefin and press-molded into a film.