JP4907584B2 - Composite membrane for oil-filled transformer conservator and manufacturing method thereof - Google Patents

Description

The present invention relates to a composite membrane for an oil-filled transformer conservator and a method for manufacturing the same , and more particularly, to a composite membrane for an oil-filled transformer conservator and a method for manufacturing the same .

  FIG. 3 shows a configuration example of the oil-filled transformer. The oil-filled transformer 10 includes a transformer body 11 composed of an iron core, a primary winding, a secondary winding, and the like, a tank 12 having a sealed structure and incorporating the transformer body 11, and a dielectric strength and a cooling effect. Insulating oil 13 sealed in the tank 12, a plurality of insulators 14 attached to the ceiling surface of the tank 12, and an upper portion of the tank 12, and connected to the tank 12 via a connecting pipe 15. A conservator 16 and a hygroscopic respirator 18 connected to the conservator 16 via a connecting pipe 17 are provided.

  The transformer body 11 includes an iron core, a primary winding, a secondary winding, and the like, and steps down and outputs an AC input voltage. The tank 12 is made of a metal that is excellent in heat dissipation, and has a structure in which high heat dissipation is obtained and insulation from the transformer body 11 is taken into consideration. The insulator 14 is attached to the tank 12 while being insulated, and is connected to the power transmission line, the distribution line, and the primary winding and the secondary winding of the transformer main body 11.

  The conservator 16 internally separates the insulating oil 13 of the oil-filled transformer 10 from the outside air to prevent oxidative deterioration of the insulating oil 13 and absorbs expansion and contraction of the insulating oil 13. An input transformer conservator composite film (hereinafter referred to as a conservator composite film) 20 is provided.

  The hygroscopic respirator 18 contains a desiccant for dehumidifying the air introduced into the conservator 16, for example, silica gel.

  FIG. 4 shows the structure of the composite membrane 20 for conservators. A composite membrane for conservators with improved oxygen gas barrier properties has been studied for application to an ultra-high voltage transformer as one of countermeasures against flow electrification, and the composite membrane for conservators 20 in FIG. 4 is disclosed in Patent Document 1. .

  The composite membrane for conservator 20 includes an EVOH film 21 as an intermediate layer using an anti-oxidation polymer material having an oxygen gas barrier property, and a nylon cloth 22 as an inner layer provided on both surfaces of the EVOH film 21. And a nitrile rubber 23 as an outer layer provided on each surface of the nylon cloth 22. The layers are bonded to each other with an adhesive.

  In the transformer main body 11, the temperature of the iron core and each winding increases with operation. When the temperature of the transformer body 11 rises, the temperature of the insulating oil 13 rises and expands. In addition, when the transformer main body 11 stops operating or operates with a light load, the temperature of the insulating oil 13 decreases and contracts. A conservator 16 is provided to absorb the expansion and contraction of the insulating oil 13.

  The conservator composite membrane 20 is in contact with the air (oxygen) from the hygroscopic respirator 18 on one side, and the insulating oil 13 from the tank 12 is in contact with the other side of the insulating membrane 13 in the tank 12. In response to the expansion or contraction, the conservator composite film 20 moves up and down to absorb the expansion / contraction of the insulating oil 13.

Therefore, the composite membrane 20 for conservators is required to have excellent oxygen gas barrier properties for preventing the deterioration of the insulating oil 13, excellent followability to deformation, and high delamination strength between layers. .
Japanese Patent Laid-Open No. 2006-237531

  However, the composite membrane 20 for conservator described in Patent Document 1 leaves room for improvement in peel strength between the intermediate layer made of EVOH film or the like and the inner layer made of nylon cloth.

Accordingly, an object of the present invention is to provide a composite membrane for an oil-filled transformer conservator that has a high peel strength between an intermediate layer made of an EVOH film or the like and a nylon cloth layer and is excellent in durability, and a method for producing the same. There is.

In order to achieve the above object, the present invention provides an intermediate layer using an antioxidant polymer material having oxygen gas barrier properties, a rubber layer provided on both surfaces of the intermediate layer, and each of the rubber layers. Nylon cloth layer provided on the outer surface (surface opposite to the intermediate layer facing surface) and the outer surface of each nylon cloth layer (surface opposite to the rubber layer facing surface) A method of manufacturing a composite membrane for an oil-filled transformer conservator comprising an outer layer made of an oil-resistant substance, the step of activating the bonding surface of the intermediate layer before bonding to the rubber layer, and the nylon A method for producing a composite membrane for an oil-filled transformer conservator, comprising: a step of coating an adhesive surface of a fabric layer with a resin-added rubber paste before adhering to the rubber layer. characterized in that it is Providing oil-filled transformer conservator composite film.

ADVANTAGE OF THE INVENTION According to this invention, the composite film for oil-filled transformer conservators which has high peeling strength between the intermediate | middle layer which consists of EVOH films etc., and a nylon cloth layer, and is excellent in durability, and its manufacturing method can be provided.

  FIG. 1 shows a composite membrane for an oil-filled transformer conservator according to an embodiment of the present invention. This composite film for oil-filled transformer conservator (hereinafter referred to as a composite film for conservator) 1 includes an intermediate layer 2 using an anti-oxidant polymer material having an oxygen gas barrier property, and both surfaces of the intermediate layer 2. A rubber layer 3 provided on the outer surface, a nylon cloth layer 4 provided on each outer surface of the rubber layer 3 (a surface opposite to the intermediate layer-facing surface), and an outer side of each nylon cloth layer 4. And an outer layer 5 made of an oil resistant material such as nitrile rubber provided on the surface (the surface opposite to the rubber layer facing surface).

  The intermediate layer 2 and the rubber layer 3 are bonded by an adhesive 6, and the rubber layer 3 and the outer layer 5 are bonded by a nylon cloth layer 4 coated with an adhesive 7.

[Intermediate layer 2]
For the intermediate layer 2, a polymer material having excellent oxygen gas barrier properties is used. Specifically, the oxygen transmission rate is 3.5 cm ³ / m ² · 24 h · atm or less at room temperature (20 to 25 ° C.) and a humidity of 0%, and 30 cm ³ / m ² · 24 h · at 50 ° C. and a humidity of 0%. A polymer material having atm or less can be preferably used. More preferably, room temperature (20-25 ° C.), an oxygen permeability at 0% ^{humidity, 2.0cm 3 / m 2 · 24h} · atm or ^{less, 50 ℃, 25cm 3 / m} 2 · 24h · atm at 0% humidity It is as follows. More preferably, the oxygen permeability is 1.0 cm ³ / m ² · 24 h · atm or less at room temperature (20 to 25 ° C.) and humidity 0%, and 21 cm ³ / m ² · 24 h · atm at 50 ° C. and humidity 0%. It is as follows.

The intermediate layer 2 is more preferably made of a polymer material that also satisfies the following conditions. That is, at 35 ° C. and a humidity of 75%, the oxygen transmission rate is 6.0 cm ³ / m ² · 24 h · atm or less, more preferably 5.0 cm ³ / m ² · 24 h · atm or less, and still more preferably 4. 0 cm ³ / m ² · 24 h · atm or less.

Moreover, since it is desirable to prevent the permeation | transmission of a water | moisture content, the intermediate | middle layer 2 uses the polymeric material which satisfy | fills the following conditions more preferably. That is, the water vapor transmission rate at room temperature (20 to 25 ° C.) is 1,000 g / m ² · 24 h or less, and at 50 ° C. is 5000 g / m ² · 24 h or less. More preferably, the water vapor transmission rate at room temperature (20 to 25 ° C.) is 950 g / m ² · 24 h or less and at 50 ° C. is 5000 g / m ² · 24 h or less.

  As such an intermediate layer 2, for example, a film of ethylene-vinyl alcohol copolymer resin (EVOH), stretched polyvinyl alcohol (stretched PVA), polyvinylidene chloride (PVDC), or the like can be suitably used.

  When using an ethylene-vinyl alcohol copolymer resin (EVOH) as the intermediate layer 2, it is preferable to use one having an ethylene copolymerization ratio of 20 to 45 mol%, more preferably 25 to 35 mol%. More preferably, it is 29-31 mol%.

  As for the thickness of EVOH, 10-30 micrometers is preferable, More preferably, it is 12-25 micrometers, More preferably, it is 14-20 micrometers.

  When using stretched polyvinyl alcohol (stretched PVA) as the intermediate layer 2, it is preferable to use biaxially stretched PVA. Moreover, since it cannot be said that stretched PVA is excellent in water vapor | steam resistance, it is preferable to use a desiccant etc. together.

  As for the thickness of extending | stretching PVA, 8-30 micrometers is preferable, More preferably, it is 10-25 micrometers, More preferably, it is 12-20 micrometers.

  When using polyvinylidene chloride (PVDC) as the intermediate layer 2, it is preferable to use a thicker film, a plurality of laminated layers, or a laminate of other materials from the viewpoint of strength.

  The thickness of PVDC is preferably 14 to 55 (assuming 27 microns × 2 sheets) μm, more preferably 18 to 40 μm, and still more preferably 20 to 35 μm.

[Rubber layer 3]
Synthetic rubber such as nitrile rubber can be suitably used for the rubber layer 3. The thickness of the rubber layer 3 is preferably 60 to 150 μm, more preferably 70 to 130 μm, and still more preferably 80 to 100 μm.

[Nylon cloth layer 4]
70-150 micrometers is preferable, as for the thickness of the nylon cloth layer 4, More preferably, it is 80-140 micrometers, More preferably, it is 90-130 micrometers.

[Outer layer 5]
For the outer layer 5, an oil-resistant substance such as nitrile rubber can be suitably used. 150-400 micrometers is preferable, as for the thickness of the outer layer 5, More preferably, it is 200-400 micrometers, More preferably, it is 250-350 micrometers.

[Adhesive 6]
The intermediate layer 2 and the rubber layer 3 are bonded with an adhesive 6. As the adhesive 6, a resin-added rubber paste can be suitably used. A rubber paste of the same quality as the outer layer 5 is preferable. In particular, phenol resin-added nitrile rubber paste is preferable. The addition amount of the phenol resin is preferably 10 to 50% of the mass of the nitrile rubber. This is determined from the viewpoints of adhesive performance, prevention of curing by addition of resin, and economical efficiency. In addition, 15 to 30% is more preferable, and 20 to 25% is more preferable.

  Before the intermediate layer 2 and the rubber layer 3 are bonded by the adhesive 6, it is necessary to activate the surface of the intermediate layer 2 in order to stabilize the adhesive strength. Examples of the activation method include heat treatment, corona discharge, primer treatment, and the like, but heat treatment is most preferable from the viewpoint of cost and the effect of removing moisture. The activation treatment is optimally performed immediately before bonding, and is preferably performed at least within several hours before bonding.

[Adhesive 7]
The rubber layer 3 and the outer layer 5 are bonded with the adhesive 7 through the nylon cloth layer 4 treated with the adhesive 7. Here, the adhesive 7 means an adhesive that coats the entire surface of the nylon cloth. As the adhesive 7, a resin-added rubber paste similar to the adhesive 6 can be suitably used. The rubber is preferably a rubber paste of the same quality as the outer layer 5.

  As a method of coating the nylon cloth layer 4 with the adhesive 7, for example, the nylon cloth is immersed in a resin-added nitrile rubber paste and kept under pressure or reduced pressure, and the rubber is impregnated in the gap between the fibers and applied. This can be done.

[Method for producing composite membrane for conservator]
The conservator composite membrane 1 can be manufactured, for example, by the following procedure. When sticking, make sure that bubbles do not get mixed in and do not become wrinkles.
(1) The adhesive 7 is coated on the nylon cloth layer 4.
(2) The rubber layer 3 is attached to (1).
(3) A surface treatment is applied to the intermediate layer 2.
(4) Apply the adhesive 6 on one side of (3).
(5) The rubber layer 3 side of (2) is attached to the application surface of (4).
(6) The adhesive 6 is applied to the exposed surface of the intermediate layer 2 in (5).
(7) The rubber layer 3 side of (2) is attached to the application surface of (6).
(8) The outer layer 5 is affixed on both outer sides of (7).
(9) Vulcanize (8).

[Effect of the embodiment of the present invention]
According to the embodiment of the present invention, it is possible to obtain a composite film for a conservator having a peel strength between layers of the composite film of 10 N / cm or more, further 20 N / cm or more.

In addition, the above-mentioned peel strength is maintained, the oxygen permeability is 0.08 cm ³ / m ² · 24 h · atm or less at room temperature (20 to 25 ° C.) and 0% humidity, and the oil resistance of the insulating oil is about It is also possible to obtain a composite film for conservators that can withstand 30,000 times or more of stretching and bending motions even in oil bending at 60 ° C.

[Other Embodiments]
The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the invention. For example, the composite membrane for conservator 1 is not limited to a so-called diaphragm type but can be applied to a so-called bag type.

  Examples of the present invention will be described below, but the present invention is not limited thereto.

[Example 1]
In accordance with the method for producing a conservator composite membrane according to the embodiment of the present invention, a conservator composite membrane 1A was produced by a mass production facility.

  FIG. 2A is a cross-sectional view of the composite membrane for conservator 1A of the first embodiment. Each layer has a stretched polyvinyl alcohol (stretched PVA) film layer 2A (thickness 12 μm), a nitrile rubber layer 3A (thickness 100 μm), a nylon cloth layer 4A (thickness 120 μm), and a nitrile rubber layer 5A (thickness 300 μm). Using. The product name “Boblon” (biaxially stretched PVA) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. was used for the stretched PVA.

  The stretched polyvinyl alcohol (stretched PVA) film layer 2A was heat-treated as an activation treatment. Nitrile rubber paste containing 20% phenol resin was used as the adhesive 6A, and the nitrile rubber layer 3A and the nitrile rubber layer 5A were vulcanized and fused by the nylon cloth layer 4A coated with the adhesive 7A. A resin-added nitrile rubber paste was used for the adhesive 7A.

(Test results)
The oxygen permeability test of Example 1 was conducted according to JIS K7126B method: 1987 at room temperature of 23 ° C. and humidity of 0% with an oxygen permeability of 0.01 cm ³ / m ² · 24 h · atm or less (measurement limit). there were. In addition, as oil resistance to insulation oil, immersed in about 100 ° C. insulation oil (type 7 No. 4) and allowed to stand for 30 days. I could endure it. Thereby, it turned out that it has the target intensity | strength.

[Comparative Example 1]
According to the method for producing a conservator composite membrane described in Patent Document 1, a conservator composite membrane 1B was produced by mass production equipment.

  FIG. 2B is a cross-sectional view of the composite membrane 1B for conservator of Comparative Example 1. For each layer, a stretched polyvinyl alcohol (stretched PVA) film layer 2B (thickness 12 μm), a nylon cloth layer 4B (thickness 120 μm), and a nitrile rubber layer 5B (thickness 250 μm) were used. The product name “Boblon” (biaxially stretched PVA) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. was used for the stretched PVA.

  The stretched polyvinyl alcohol (stretched PVA) film layer 2B was heat-treated as an activation treatment. Nitrile rubber paste was used for the adhesive 6B and the adhesive 8B, and the nitrile rubber layer 5B was bonded to the nylon cloth layer 4B by vulcanization fusion.

[Comparative Example 2]
According to the method for manufacturing a composite membrane for conservator of the embodiment of the present invention, a composite membrane for conservator 1C was manufactured by mass production equipment. However, the film layer 2C and the nylon cloth layer 4C were bonded without providing a layer corresponding to the nitrile rubber layer 3A.

  FIG. 2C is a cross-sectional view of the conservator composite film 1C of Comparative Example 2. For each layer, a stretched polyvinyl alcohol (stretched PVA) film layer 2C (thickness 12 μm), a nylon cloth layer 4C (thickness 120 μm), and a nitrile rubber layer 5C (thickness 350 μm) were used. The product name “Boblon” (biaxially stretched PVA) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. was used for the stretched PVA.

  The stretched polyvinyl alcohol (stretched PVA) film layer 2C was heat-treated as an activation treatment. The adhesive 6C was repeatedly coated with 20% phenol resin-added nitrile rubber paste, and the nylon cloth layer 4C coated with the adhesive 7C was adhered to vulcanize and fuse the nitrile rubber layer 5C. A resin-added nitrile rubber paste was used for the adhesive 7C.

(Peel adhesion strength test)
Using Example 1 and Comparative Examples 1 and 2 above, the peel strength was measured by a peel adhesion strength test.

  The peel adhesion strength test was performed by a method according to JIS K6404-5: 1999. Each sample was attached to a tensile tester, and 180 degree peel strength (N / cm) was measured.

  The measurement results were 29 N / cm for Example 1, 2.9 N / cm for Comparative Example 1, and 4.4 N / cm for Comparative Example 2. From this, it was found that the peel strength when using the layer structure and adhesive of Example 1 was extremely high and excellent.

[Example 2]
A composite membrane for conservator similar to that of Example 1 was manufactured by a laboratory facility according to the method for manufacturing a composite membrane for conservator of the embodiment of the present invention.

(Confirmation of effect of activation treatment on intermediate layer 2 surface)
In addition to those manufactured by activating the surface of the intermediate layer 2 by heat treatment in the same manner as in Example 1, the surface of the intermediate layer 2 is activated by corona treatment as a discharge treatment instead of heat treatment, and primer treatment. When the above-mentioned peel adhesion strength test was performed, the heat treatment was 22.7 N / cm, the corona treatment was 26.3 N / cm, and the primer treatment was 9. It was 9 N / cm.

Example 3
A composite membrane for conservator similar to that of Example 1 was manufactured by a laboratory facility according to the method for manufacturing a composite membrane for conservator of the embodiment of the present invention. However, instead of the 20% phenol resin added nitrile rubber paste, 30% phenol resin added nitrile rubber paste, 50% phenol resin added nitrile rubber paste, and 100% phenol resin added nitrile rubber paste were used.

(Confirmation of effect of added phenolic resin)
When the above-mentioned peel adhesion strength test was performed for each, the one with 30% phenol resin added was 21.3 N / cm, and the one with 50% phenol resin added and 100% phenol resin added was not peelable. .

It is sectional drawing of the composite film for conservators which concerns on embodiment of this invention. It is sectional drawing of the composite film for conservators of an Example and a comparative example. It is a block diagram which shows the structural example of an oil-filled transformer. It is sectional drawing which shows the structure of the conventional composite membrane for conservators.

Explanation of symbols

1: composite film for conservator, 2: intermediate layer 3: rubber layer, 4: nylon cloth layer, 5: outer layer 6: adhesive, 7: adhesive
1A to 1C: Composite membrane for conservator 2A to 2C: Stretched PVA film layer 3A: Nitrile rubber layer, 4A to 4C: Nylon cloth layer 5A to 5C: Nitrile rubber layer, 6A to 6C: Adhesives 7A, 7C: Adhesive 8B: Adhesive 10: Oil-filled transformer, 11: Transformer body, 12: Tank 13: Insulating oil, 14: Insulator, 15: Connecting pipe 16: Conservator, 17: Connecting pipe, 18: Hygroscopic respirator 20 : Conservator composite film, 21: Intermediate layer (EVOH film)
22: Inner layer (nylon cloth), 23: Outer layer (nitrile rubber)

Claims (9)

An intermediate layer using an antioxidant polymer material having an oxygen gas barrier property, a rubber layer provided on both surfaces of the intermediate layer, and an outer surface of each rubber layer (the intermediate layer facing surface is Oil comprising a nylon cloth layer provided on the opposite surface) and an outer layer made of an oil-resistant substance provided on the outer surface of each nylon cloth layer (the surface opposite to the rubber layer-facing surface) A method of manufacturing a composite membrane for an input transformer conservator,
A step of activating the adhesive surface of the intermediate layer before adhering to the rubber layer;
Coating the adhesive surface of the nylon cloth layer with a resin-added rubber paste before bonding to the rubber layer;
The manufacturing method of the composite film for oil-filled transformer conservators characterized by including this. An oil-filled transformer conservator composite film manufactured by the method of manufacturing an oil-filled transformer conservator composite film according to claim 1. The intermediate layer and the rubber layer, and the nylon cloth layer and the outer layer are bonded with the adhesive resin-added rubber paste,
3. The oil-filled transformer connector according to claim 2 , wherein the adhesive resin-added rubber paste is a phenol resin-added nitrile rubber paste in which the amount of phenol resin added is 10 to 50% of the mass of the nitrile rubber. Composite membrane for beta. The composite membrane for an oil-filled transformer conservator according to claim 2 or 3 , wherein the activation treatment is a heat treatment. The composite film for an oil-filled transformer conservator according to any one of claims 2 to 4 , wherein the rubber layer is made of nitrile rubber. The composite film for an oil-filled transformer conservator according to any one of claims 2 to 5 , wherein the rubber layer has a thickness of 60 to 150 µm. The polymer material constituting the intermediate layer is oxygen at room temperature (20 to 25 ° C.), humidity 0%, oxygen permeability of 3.5 cm ³ / m ² · 24 h · atm or less, 50 ° C., humidity 0%. The transmittance is 30 cm ³ / m ² · 24 h · atm or less, the water vapor permeability at room temperature (20 to 25 ° C.) is 1000 g / m ² · 24 h or less, and the water vapor permeability at 50 ° C. is 5000 g / m ² · 24 h. The composite film for an oil-filled transformer conservator according to any one of claims 2 to 6 , wherein the composite film is the following polymer material. The polymeric material is ethylene - vinyl alcohol copolymer resin (EVOH), either one of claims 2 to 7, characterized in that a stretched polyvinyl alcohol (stretching PVA), or polyvinylidene chloride (PVDC) The composite membrane for oil-filled transformer conservators according to item 1. The composite film for an oil-filled transformer conservator according to any one of claims 2 to 8 , wherein the oil-resistant substance constituting the outer layer is nitrile rubber.

Images