JPS643285B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of applying insulation coating treatment to an arbitrary shape on, for example, the outer periphery of an optical transmission member.

Hereinafter, a case where the present invention is applied to an optical transmission member will be described.

Recently, the range of applications of optical fibers, photodiodes, etc. has been increasing, and they are being used in various electrical devices and devices. For example, one example of the application of optical fibers to high-voltage electrical equipment is the application to failure detection devices such as power capacitors, in which the electrical equipment body is installed on top of a pedestal insulated with ceramic or resin insulators.

An example of application will be specifically explained with reference to FIG.

In Figure 1, 1 is an electrical device using an insulating stand such as a power capacitor, 2 is the main body of the electrical device, 3 is an insulator for insulation, 4 and 5 are the upper and lower frames of the insulating stand, and 6 is the main body of the electrical device. 2 is a protection device generating section that has a function of electrically detecting the occurrence of an abnormality and converting the signal into an optical signal; 7 is a protection device light receiving section that receives the signal and operates an electrical contact; 8 is a connection between 6 and 7. This is an optical transmission member (hereinafter referred to as an optical fiber barcode) to be connected.

Optical fiber barcodes are usually cylindrical cords coated with flexible organic materials such as polyethylene, and there are no commercially available cords with insulation coatings that take creepage voltage into consideration, such as cords with pleated coatings. This is the current situation, and when applying a coating with irregularities such as pleats, continuous production by extrusion molding or the like is almost impossible.

However, when optical fiber barcodes are applied to high-voltage electrical equipment such as those mentioned above, ground voltage is constantly applied between both ends of the optical fiber barcodes.
In reality, insulation treatment as shown in FIG. 2 is applied to protect the coating surface from staining and deterioration or creeping dielectric breakdown during rain.

In FIG. 2, 3 is a ceramic or resin insulator having a through hole, and 8 is an optical fiber bar cord that passes through the insulator 3. 9 is resin injected for corona prevention or waterproofing.

Optical fiber barcodes that have been insulated as shown in Figure 2 require insulators depending on the length and diameter of the optical fiber barcode, and in the case of ceramic insulators, they are particularly susceptible to earthquakes and other vibrations. Since cracks are likely to occur, sufficient anti-vibration measures are required.

Furthermore, after inserting the optical fiber barcode, it is necessary to fill the air gap in the insulator through hole and inject resin for waterproofing purposes.

The conventional insulation coating method described above takes a long time to manufacture, is expensive, and is not sufficiently waterproof.

Furthermore, the connection of optical fiber barcodes is always accompanied by heavy insulators, which significantly reduces work efficiency when assembling electrical equipment.
Furthermore, it was also impossible to connect the optical fiber bar cord in a bent state.

The present invention has been made in view of the above-mentioned drawbacks, and it is an object of the present invention to provide an extremely simple and highly reliable insulation coating method when, for example, an optical transmission line is incorporated into high-voltage electrical equipment.

That is, the present invention provides a prepolymer having a terminal hydroxyl group consisting of a hydrogenated product of a polyhydroxybutadiene polymer having a melting point of 40 to 130°C and a solid at room temperature and an isocyanate compound, and the formula (): 2,4-toluene diisocyanate represented by
The present invention relates to an insulating coating method in which a molding material made of dimer is preformed into a predetermined shape, the preformed molded product and an insulating coating are placed in a mold, heated and melted, and then hardened.

Hydrogenated product 2.0 of polyhydroxybutadiene polymer, which is the main ingredient of the molding material used in the present invention
A prepolymer having a terminal hydroxyl group by reacting ~2.5 moles with 1 mole of an isocyanate compound is a thermosetting resin, and the base resin and the 2,4-toluene diisocyanate dimer represented by the formula (), which is a curing agent, are The ratio is the number of moles of isocyanate groups in the curing agent to the number of moles of hydroxyl groups in the base agent.
A ratio of NCO/OH=0.8 to 1.2 is preferred.

The thermosetting resin used for the molding material has a melting point within the above range, and when the molding material consisting of the main resin and curing agent is stored at room temperature or a low temperature below 0°C,
It has a pot life of more than a month (flows depending on the melting point temperature).

If the melting point of the hydrogenated polyhydroxybutadiene polymer used in the present invention is lower than 40°C, it will tend to flow at room temperature and cannot maintain its preformed shape. Furthermore, since it is sticky, workability is significantly reduced. On the other hand, when the temperature is higher than 130°C, the melting temperature during molding becomes high, so a gelation reaction occurs during melting, resulting in poor appearance such as resin missing parts and voids, which is not preferable.

The preformed molded article of the present invention is placed inside a mold so as to cover all or a portion (desired portion) of the insulating coating, and is heated and hardened. Further, during heat curing, it is desirable that the sum of the volumes of the preformed molded product and the insulating coating be equal to or larger than the volume of the hollow part of the mold so that voids do not occur inside.

Since the mold only needs to be heated by placing a preformed molding material therein for covering the insulating coating, a relatively simple structure is sufficient.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

FIG. 3 shows an example of a manufacturing apparatus for obtaining a preformed molded product used in the present invention, where 10 indicates a normal vacuum stirring apparatus, and 11
indicates a molding material consisting of a mixture whose main components are a thermosetting resin main ingredient having a melting point in the range of 40 to 130°C as described above, and a curing agent thereof. Reference numeral 12 denotes a mold for the preform, but a plastic case with excellent mold releasability, for example, can also be used. After injecting the thermosetting resin mixture, which has been thoroughly degassed under vacuum at a temperature above the melting point of the molding material using the vacuum stirring device 10, into the mold 12, it is cooled to room temperature and the mold is removed, resulting in a preformed molding. Thing 1
3 can be easily obtained.

In this example, as the molding material 11, 2.3 moles of a hydrogenated polyhydroxybutadiene polymer as a main ingredient and 1 mole of 4,4'-diphenylmethane diisocyanate were reacted to form a prepolymer having terminal hydroxyl groups. The number of moles of the curing agent is adjusted to be equal to the number of moles.

Next, FIG. 4 shows a partial sectional view of the two-part simple mold used in this example. 14a is the main body of the upper mold, and 14b is the main body of the lower mold. Both are equipped with a heating device (not shown). Reference numeral 15 indicates a fastener for clamping the mold, 16 indicates a fastener for fixing the optical fiber bar code, and 18 indicates a thermosetting resin as a molding material.

In order to perform molding, first, the upper mold 14a and the lower mold 14b are opened, a preformed molded product is placed in each molded product, and the molded product is heated to the melting temperature of the molded product. Next, insert the optical fiber barcode 8 into the lower mold 14.
b and fixed to the mold using fasteners 16a and 16b, then the upper mold 14a is placed together and the mold is clamped using the fastener 15, and maintained at a predetermined temperature (for example, 140 to 160°C). Cure for 1-2 hours). After cooling, the mold is opened and the molded product is taken out.

FIG. 5 is a sectional view showing the insulating coating of the optical fiber bar code after demolding. Reference numeral 18 indicates an insulating coating after curing, and reference numerals 8a and 8b indicate connection terminals to photosensitive elements, etc. provided at both ends of the optical fiber bar code 8, respectively.

According to the method of the present invention, unlike the conventional method shown in FIG. 2, there is no need to inject resin after passing an optical fiber bar code through the through hole of the insulator, and moreover, it is possible to use a simple mold. Furthermore, it is possible to form an insulating coating even after connecting terminals are provided at the end of the optical fiber barcode, and it can be done on-site as long as there is a heating source (such as an electric heater). It has excellent characteristics. Furthermore, compared to conventional methods, this method has extremely superior waterproof properties because it is an integrally molded part. The mold clamping force of the mold may be extremely low, for example, by tightening it with fingers, or by using only the weight of the upper mold, especially without using a clamping tool.

The insulation coating method according to the present invention is suitable for insulation coating of transmission lines between different potentials of all kinds of electric equipment, and especially when applied to insulation coating of signal transmission lines from ultra-high voltage parts to ground potential, it has a large safety aspect. Effects can be obtained.

Incidentally, in the above explanation, the case where the present invention is applied to an optical transmission member has been explained, but it goes without saying that the present invention is not limited to this.

As explained above, according to the present invention, there is an effect that a high-performance insulation coating can be easily obtained.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an example of the application of the optical transmission member;
Figure 2 is a cross-sectional view showing an example of insulation coating using the conventional method.
FIG. 3 is a diagram showing an example of manufacturing a preformed molding material used in the present invention, FIG. 4 is a cross-sectional view showing an example of manufacturing according to an embodiment of the present invention, and FIG. FIG. 3 is a cross-sectional view showing a photoconductive member provided with an insulating coating. In the figure, 8 is a light transmission member, 13 is a preformed molding material, 14 is a mold, and 18 is an insulating coating. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A preprimer having a terminal hydroxyl group consisting of a hydrogenated product of a polyhydroxybutadiene polymer having a melting point of 40 to 130°C and solid at room temperature and an isocyanate compound, and formula (1): 2,4-toluene diisocyanate represented by
An insulating coating method comprising: preforming a molding material made of dimer into a predetermined shape, placing the preformed molded article and an insulating coating in a mold, heating and melting, and then curing. 2. The insulation coating method according to claim 1, wherein the insulation coating is an optical fiber bar code.