JPH1058545A - Hydraulic curing molding method, coil, and method for producing laminated molded product - Google Patents

Abstract

(57) [Summary] [Problem] To improve the molding technology of prepreg insulation,
Improve various aspects such as releasability and workability. Hydraulic curing in which a coil is covered with a prepreg made of a thermosetting resin, or a plate or other shaped element is laminated through the prepreg, and the prepreg is cured by a liquid heating / pressurizing medium. In the molding method, a polyolefin-based material or a polyethylene-based material having a molecular weight of 20,000 or less is used as a heating / pressing medium. Regarding the curing of the prepreg, by using a polyolefin-based or polyethylene-based material for the heating / pressurizing medium, the exfoliation property and the releasability are excellent, the working time can be shortened, and the insulation properties of the coil can be improved. There is no medium intrusion between layers and surface layers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic curing molding method for curing a prepreg material with a liquid heating / pressurizing medium when coating or laminating a coil with a prepreg material made of a thermosetting resin. And a method for producing a coil and a laminated molded product by applying the method.

[0002]

2. Description of the Related Art Conventionally, a coil is covered with a prepreg made of a thermosetting resin, or a plate or other shaped element is laminated through the prepreg, and the prepreg is cured by a liquid heating / pressing medium. Hydraulic curing molding methods are known.

For example, in a method of forming a coil insulation coating, a technique has been proposed in which a hard material such as a metal plate or a glass mat is applied to the surface of a prepreg and cured to improve the smoothness and dimensional accuracy of the surface ( Example: USP 30507
87). In this case, asphalt compound is used as a heating / pressing medium. However, in such a method, although the finish of the linear portion is good, the end of the coil has a curved shape and cannot be made of a hard material, so that the smoothness and the dimensional accuracy are somewhat inferior. As a heating / pressurizing medium, asphalt compound is used, but because of its wide molecular weight distribution, it slightly penetrates into the insulating layer at the coil end. Furthermore, since the molding device is used repeatedly, a layer of deposits is gradually formed on the pipe wall in the device,
A decrease in flow rate occurs. Also, in the operation of removing the backing plate and the release tape from the coil after molding, the black and thinly hardened asphalt compound is inferior in releasability, and it is not easy to remove what adheres to a complicated shape portion. Furthermore, the asphalt compound is scattered as dust at the time of release from the mold, so that there is a problem that workability is inferior.

[0004] On the other hand, in the method of manufacturing a laminated plate, generally, a prepreg sheet is laminated on an elementary body, and pressure-cured by a hot press. In the case of cylinders and complicated shapes, the method of laminating on a mold and curing by heating and pressurizing has been used in many cases, but recently high-temperature hydraulic forming has been developed (eg, next-generation composite material technology) Handbook: p245).

[0005] As a heating and pressurizing medium used in these techniques, a heat-resistant heat medium has been frequently used, and among them, silicon oil is generally used. In this case, the silicon oil is always liquid, and the silicon oil adheres to the surface of the molded article when the molded article is taken out, so that the surface must be cleaned. If the silicone oil comes into contact with the molded product while it is being cured, it will be injected into the lamination gap, causing a defect such that normal characteristics cannot be obtained.

[0006]

In the prior art, the smoothness and dimensional accuracy at the end of the coil are poor, and the molecular weight distribution of the asphalt compound used as a heating and pressurizing medium is wide. There are problems such as a slight penetration into the layer. In addition, since the molding device is used repeatedly, a layer of deposits is gradually formed on the pipe wall in the device, which causes a decrease in flow rate, and in the work of removing the backing plate and release tape from the coil after molding. However, there is also a problem that asphalt compound hardened in black is attached and cannot be easily removed. Furthermore, the asphalt compound is scattered as dust at the time of release from the mold, so that there is a problem that workability is inferior.

On the other hand, in the method of manufacturing a laminated board, a heat-resistant heat medium is frequently used as a heat and pressure medium. Among them, silicon oil is generally used, but silicon oil is always liquid. Silicon oil adheres to the surface of the molded product when the molded product is removed, so the surface needs to be cleaned, or the silicone oil comes into contact with the lamination gap during curing of the molded product, and normal characteristics cannot be obtained. Disadvantages arose.

The present invention has been made in view of such circumstances, and has been made by improving a prepreg insulation hardening technique to improve moldability,
It is an object of the present invention to provide a hydraulic hardening molding method capable of improving various points such as releasability, workability, and the like, and a method of manufacturing a coil and a laminated molded product by applying the method.

[0009]

According to the first aspect of the present invention, a coil is covered with a prepreg made of a thermosetting resin, or a plate-like or other shape is formed through the prepreg. In a hydraulic curing molding method in which the element bodies are laminated and the prepreg is cured by a liquid heating / pressing medium, a polyolefin-based material or a polyethylene-based material having a molecular weight of 20,000 or less is used as the heating / pressing medium. A hydraulic curing molding method is provided.

In the present invention, the use of a polyolefin-based or polyethylene-based medium as the heating / pressurizing medium means that both components have no reactivity with the thermosetting resin, are incompatible, and have a releasability from metals and insulators. Due to having excellent characteristics. Also,
Regarding the molecular weight, when the molecular weight is large, even if it is melted, the fluidity is not sufficient, and the injection into the apparatus and the return to the apparatus are hindered. Therefore, the molecular weight of about 20,000 is the upper limit that can be used.

According to a second aspect of the present invention, in the hydraulic setting method according to the first aspect, a polyolefin-based material or a polyethylene-based material having a melting point of 135 ° C. or less is used as the heating / pressing medium. To provide a hydraulic curing molding method.

In the present invention, with respect to the melting point of 135 ° C. or lower, the curing temperature of the prepreg insulation is usually 100 to 180.
Due to the large range of ° C. Fluidity is 2 degrees above melting point
Temperatures between 0 and 30 ° C. higher are required. In addition, since the piping temperature of the apparatus must be maintained at a corresponding height, both the equipment cost and the maintenance cost are expensive, but the present invention can improve these points.

According to a third aspect of the present invention, in the hydraulic setting method of the first aspect, the heating and pressurizing medium is 150
Provided is a hydraulic curing molding method characterized by using a polyolefin-based material or a polyethylene-based material having a viscosity at 100 ° C. of 100 Pa · S or less.

In the present invention, the viscosity at 150 ° C. is set to 100 Pa · S for the same reason as described above.

According to a fourth aspect of the present invention, there is provided the hydraulic curing molding method according to any one of the first to third aspects, wherein low density polyethylene is applied as the polyethylene material. provide.

According to a fifth aspect of the present invention, there is provided the liquid curing molding method according to any one of the first to fourth aspects, wherein a polyethylene wax-based material obtained by cracking polyethylene is applied as the polyethylene-based material. A pressure curing molding method is provided.

The invention of claims 4 and 5 is based on the fact that low density polyethylene has a lower melting point and lower viscosity even at the same molecular weight than high density polyethylene. Polyethylene wax has more excellent fluidity and mold release characteristics than general polyethylene, and is particularly excellent in workability.

According to a sixth aspect of the present invention, there is provided the liquid-pressure curing molding method according to any one of the first to fifth aspects, wherein a polyethylene-based material containing an additive such as an antioxidant or an antistatic agent is blended. Provided is a hydraulic curing molding method characterized by being applied.

In the present invention, when additives such as an antioxidant and an antistatic agent are used as this type of heat medium, they are exposed to high temperatures for a long period of time. This is effective from the viewpoint of long-term stability of the material since the viscosity may increase and the viscosity may increase. Further, the antistatic agent is effective also from the viewpoint of stability since there is a possibility of flow electrification when the flow velocity in the apparatus piping is high.

According to a seventh aspect of the present invention, a coil made of a conductor is wrapped with a prepreg-shaped insulating tape made of a thermosetting resin, and a polyamide plate is applied to the outside of the insulating tape. The shrinking tape is set in a wound state in a pressure vessel, and the inside of the pressure vessel is depressurized and then heated, and heated and heated in the same pressure vessel made of a polyolefin-based material or a polyethylene-based material having a molecular weight of 20,000 or less. A method for manufacturing a coil, comprising: injecting a pressurized medium, and thereafter switching to pressurization to cure the prepreg insulating tape.

According to the invention of claim 8, in the method of manufacturing a coil according to claim 7, the polyamide plate has a melting point of 2%.
Provided is a method for manufacturing a coil, characterized by using a coil having a thickness of 0.2 to 5.0 mm at a temperature of 00 ° C. or higher.

In the seventh and eighth aspects of the present invention, a polyamide plate having a melting point of 200 ° C. or more is used as a backing plate in coil forming. Examples of the polyamide plate include nylon 6, 46, 66, and the like. At present, a hard backing plate such as a metal plate or a laminated plate is used. This is excellent for a straight portion, but is insufficient because it cannot be used for a curved portion such as a coil end. However, if a polyamide plate is used, it is possible to sufficiently cope with a curved portion, and a product having uniform dimensions and stability on all surfaces of the coil can be manufactured. In the case of a metal or the like, it is necessary to apply a release agent in advance. However, the use of a polyamide plate eliminates the need for the release agent, and provides advantages such as easy removal.

According to the ninth aspect of the present invention, a base material of a fiber-reinforced composite material having a plate shape or another shape laminated via a prepreg sheet made of a thermosetting resin is formed into a bag shape with a film having a melting point of 200 ° C. or more. After wrapping it in a mold and heating it, a heating / pressurizing medium made of a polyolefin-based material or a polyethylene-based material having a molecular weight of 20,000 or less is injected into the mold, and the prepreg sheet is pressed. Provided is a method for producing a laminated molded product, which is characterized by being cured.

In the present invention, a polyamide sheet having a melting point of 200 ° C. or more is used in the method of forming a laminate. Examples of the polyamide sheet include nylon 6, 46 and 66. With conventional silicone oil, there is a problem in workability such as using a solvent for wiping the amount adhered to the surface, but when using the pressurized medium according to the present invention, it is solid at room temperature to work, It is easy without worry. In addition, since the molded product can be externally pressurized with a heating medium under reduced pressure by using a polyamide sheet, the content voids can be extremely reduced, and a high-quality laminated board can be manufactured.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of an apparatus used to carry out the method of the present invention.

The apparatus of this embodiment is roughly divided into
And a medium heating container 2. The heating / pressurizing medium 3 is accommodated in the medium heating container 2 and is stirred by the stirring motor 4.

A coil or a laminated plate (typically a model coil) 5 is accommodated in the impregnation container 1 via a coil installation container 6. In the coil installation container 6, a valve 7 is provided. The heat medium 3 is supplied through an introduction pipe 8 having the heat medium. The impregnation vessel 1 is provided with a pipe 10 with a valve 9 for discharging nitrogen gas (N ₂ ) and a compound meter 11.

(Embodiments 1 to 5) As the model coil 5,
A mica prepreg tape that cures at 150 ° C. is wound on the conductor six times in one-half wraps, a Teflon tape is placed thereon, and a 2 mm thick nylon 66 is set as a backing plate. Was used.

The model coil 5 was placed in the impregnation vessel 1 shown in FIG. 1 via the coil installation vessel 6, and the inside of the impregnation vessel 1 was heated to 150 ° C. while reducing the pressure. After a predetermined time,
The heating / pressurizing medium 3 in the medium heating vessel 2 which had been preheated to 150 ° C. in advance was injected into the coil installation vessel 6 through the introduction pipe 8. The heating / pressurizing medium 3 was polyethylene wax in Examples 1 to 3 shown in Table 1, and
Then, polyethylene was used. The average molecular weight of the polyethylene wax used in Example 1 was 2000, and Example 2
Is 3500, and in Example 3, it is 5000. The average molecular weight of the polyethylene used in Example 4 was 1000
0 and 20,000 in the fifth embodiment. The melting point of the heating / pressurizing medium 3 is from 107 ° C. to 133 ° C.
And the viscosity at 150 ° C. ranges from 0.25 to 50.0 Pa · S.

After a predetermined time, the pressure in the impregnation vessel 1 was switched from reduced pressure to increased pressure, and this state was maintained until the curing was completed. Thereafter, the heating / pressurizing medium 3 was returned to the original medium heating container 2. After cooling in the impregnation vessel 1, the model coil 5 was taken out, and the release tape and the attached heating / pressing medium on the surface side of the model coil 5 were removed to obtain a test coil.

As the appearance of the coil, the penetration of the mica prepreg tape between the layers and the ease of workability were checked. In Table 1, those indicated by triangles are slightly good, those indicated by circles (○) are good, and those indicated by double circles are very good. The appearances of Examples 1 to 5 were all good as shown in Table 1.

The formed coil was inspected for the degree of penetration of the heating / pressurizing medium, the peelability, the workability, the v-tan δ ratio, and the breaking characteristic test (BDV ratio) by the short-time pressurization method. The degree of penetration was extremely small in Examples 4 and 5, slightly good in Example 1, and good in Examples 2 and 3. Peelability was good in all Examples. The workability was extremely good in Examples 1 to 3, good in Example 4, and slightly good in Example 5. v-tan δ
The lower the ratio, the better, Examples 2 and 3 were the best. In addition, the BDV ratio was sequentially increased according to Examples 1 to 5.

(Comparative Example 1) The configuration of the model coil 5 was the same as that of the above-described embodiment except that only the backing plate was an iron plate having a thickness of 2 mm. As a heating / pressurizing medium, an asphalt compound was used. The curing conditions were the same as in the examples.

From Table 1, it can be seen that each example of the present invention is superior to the characteristics of the product of Comparative Example 1.

Example 6 Although not shown in Table 1, in this example, a prepreg sheet was prepared by impregnating a glass cloth with an ethoxy resin. A nylon 66 sheet was wound on an iron cylinder having an outer diameter of 500 mm and a length of 500 mm, an epoxy prepreg sheet was wound to a thickness of 10 mm, and a nylon 66 sheet was further arranged.

This was placed in the impregnation vessel 1, and the same medium as in Example 3 previously melted and heated to 150 ° C. was injected and pressure-cured. Thereafter, the medium was returned, and after cooling, a molded sample of the cylindrical laminated product was taken out.

In the laminated molded product obtained in Example 6,
The releasability was good, and the heat and pressure medium hardly penetrated into the end of the laminated molded product, indicating that the workability was extremely good.

(Comparative Example 2) Although not shown in Table 1, the conditions were almost the same as in Example 6, except that the heating and pressurizing medium was changed to silicone oil.

As a result, the obtained sample as a laminated molded product had stickiness due to adhesion of silicone oil and was inferior in workability. In addition, the heating and pressurizing medium entered the end of the laminated molded product, and slightly penetrated the surface.
Therefore, even if the surface was wiped off with a solvent, the heating / pressurizing medium could not be completely wiped off, resulting in inferior quality.

(Other Embodiments) As the heating / pressurizing medium 3,
When a test similar to that of the above examples was performed using a polyolefin-based material, substantially the same effects as those shown in the above examples were observed. Further, when nylon 6, 46 or the like was used as the backing plate, the same effect as in the above-described example was observed.

[0041]

[Table 1]

[0042]

As described above in detail, according to the present invention, the prepreg is cured by using a polyolefin-based or polyethylene-based medium as the heating / pressurizing medium, so that the coil can be stripped and released. It is excellent in workability, shortens the working time, improves the insulation properties of the coil, and in a laminated molded product, there is no penetration into the interlayer or surface layer, so that the workability and the quality can be improved. Thus, according to the present invention,
An excellent effect is achieved in that various aspects such as moldability, mold release properties, and workability can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an apparatus configuration for performing a method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Impregnation container 2 Medium heating container 3 Heating / pressurizing medium 4 Stirring motor 5 Model coil 6 Coil installation container 7 Valve 8 Inlet pipe 9 Valve 10 Gas pipe 11 Kneading meter

Claims (9)

[Claims] 1. A liquid pressure for covering a coil with a prepreg made of a thermosetting resin, or laminating a plate-shaped or other shaped element through the prepreg, and curing the prepreg with a liquid heating / pressing medium. In the curing molding method, a polyolefin-based material or a polyethylene-based material having a molecular weight of 20,000 or less is used as the heating / pressurizing medium. 2. The hydraulic curing molding method according to claim 1, wherein a polyolefin-based material or a polyethylene-based material having a melting point of 135 ° C. or less is used as the heating / pressing medium. Method. 3. The method according to claim 1, wherein the heating and pressurizing medium has a viscosity at 150 ° C. of 1
A hydraulic curing molding method characterized by using a polyolefin-based material or a polyethylene-based material having a pressure of 00 Pa · S or less. 4. The hydraulic curing molding method according to claim 1, wherein low density polyethylene is applied as the polyethylene material. 5. The hydraulic hardening molding method according to claim 1, wherein a polyethylene wax-based material obtained by cracking polyethylene is applied as the polyethylene-based material. 6. The hydraulic curing molding method according to any one of claims 1 to 5, wherein a polyethylene-based material containing an additive such as an antioxidant or an antistatic agent is applied. Hydraulic molding method. 7. A coil made of a conductor is wrapped with a prepreg-shaped insulating tape made of a thermosetting resin on the surface thereof, a polyamide plate is put on the outside of the insulating tape, and a heat-shrinkable tape is wound on the outside. It was installed in a pressure vessel as a rotated state, and after reducing the pressure inside the pressure vessel, it was brought into a heated state, and a molecular weight of 200
A method for manufacturing a coil, comprising: injecting a heating / pressurizing medium made of a polyolefin-based material or a polyethylene-based material of 00 or less, and thereafter switching to pressurizing to cure the prepreg insulating tape. 8. The method for manufacturing a coil according to claim 7, wherein a polyamide plate having a melting point of 200 ° C. or more and a plate thickness of 0.2 to 5.0 mm is used. Method. 9. A plate-like or other elementary body of a fiber-reinforced composite material laminated via a prepreg sheet made of a thermosetting resin, wrapped in a bag shape with a film having a melting point of 200 ° C. or more, and After being placed in a mold and heated, a heating / pressurizing medium composed of a polyolefin-based material or a polyethylene-based material having a molecular weight of 20,000 or less is injected into the mold, and the prepreg sheet is cured by applying pressure. Manufacturing method of a laminated molded article.