JP3432071B2 - Resin composition for wire sealing casting and wire sealing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to connecting joint ends of a plurality of assembled wires (electric wires or cables) to each other.
The present invention relates to an electric wire sealing casting resin composition for an indoor assembled electric wire, which is obtained by performing connection processing in one connected body (casting container).

[0002]

2. Description of the Related Art When sealing an end portion or a connecting portion of an electric wire or a cable (hereinafter, simply referred to as "electric wire") for insulation, as shown in FIG. A sealing casting operation is performed in which a casting container 2 made of a material such as vinyl resin is placed, and the resin composition 3 is injected into the casting container 2 and cured. In addition,
This figure shows a state in which the conductor 4 of the electric wire 1 is connected by a joint terminal 5 and is sealed. Here, a thermosetting resin such as an epoxy resin is used as the resin composition. That is, the main agent and the curing agent are mixed and cast using a mixing and casting machine, and the curing work is completed and the sealing work is completed in 10 minutes to several hours. It should be noted that these resins are mainly used that generate heat when the curing reaction starts. Further, after the resin inside is cured, the casting container 2 becomes a joint cap that protects the resin portion.

Here, the heat generated when the resin is cured has been a problem. That is, curing causes the temperature to drop to 9
Since the temperature rises from 0 ° C to nearly 140 ° C, the casting container itself may be deformed and unusable depending on the material, and the product value may be significantly impaired. On the other hand, means such as cooling from the outside of the container is also possible, but there is concern about insulation failure due to mixing of water, etc.
It could not be adopted due to equipment reasons.

[0004]

DISCLOSURE OF THE INVENTION The present invention can use a casting container made of a material having low heat resistance such as inexpensive hard vinyl chloride resin or polyolefin resin, and the thermal deformation of the casting container can be used. An object of the present invention is to provide a resin composition for electric wire encapsulation casting, which can prevent a decrease in commercial value due to the above.

[0005]

The electric wire sealing casting resin composition of the present invention has a particle diameter of 10 μm as a non-breathable, non-hygroscopic and insulating additive as described in claim 1. Above 1
It has a structure in which bead-shaped glass of 2 μm or less is added. The electric wire sealing casting resin composition of the present invention, even if the contained base resin component generates heat due to curing, the amount of heat generation is small because the additive material that does not participate in heat generation is mixed, and therefore the casting container Deformation and the like are prevented in advance.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the additive must have an insulating property. Further, in order to prevent moisture and the like from entering the inside and losing the insulation inside the sealed product, it is necessary to be non-air-permeable and non-hygroscopic. Further, it is necessary to select a resin composition for electric wire encapsulation casting which has excellent adhesion to the base resin component. As such a material, a powder or spherical body made of a resin such as a nylon resin or a phenol resin, or a powder or a granular body made of an inorganic material such as glass or silica can be used. It is preferable that the glass is made of glass because it generally has a relatively low coefficient of thermal expansion as compared with resin and has a high insulating property.

Here, the cured resin has an insulating property (volume resistivity) of 10 ¹² Ω · cm or more and a withstand voltage of ¹⁵ k.
It is required to be V or more.

Further, as the shape of the additive material, it is necessary to select a shape which is excellent in the mixing property with the base resin component and in which "embracing" of bubbles and the like is small. In addition, since it is necessary that continuous cells and the like do not occur from the outside to the end of the wire after curing, the non-fibrous form is preferable. It should be noted that even if it is fibrous and has a fiber length of about 1 mm or less, the above-mentioned open cells and the like are unlikely to occur, and therefore, it can be selected after examination in advance. In addition,
The substantially spherical additive is the best in terms of insulating property and kneading property. In this case, the particle size is preferably 10 μm or more and 12 μm or less. This is because if it is less than 10 μm, it is difficult to uniformly mix it with the base resin component and the amount of heat generation cannot be reduced, and if it is more than 12 μm, it is difficult to form a spherical shape. The flame combustion method is known as a method for obtaining such spherical and glass or silica having an appropriate particle diameter.
According to this method, good spherical particles can be obtained.

Further, the resin component is 1 as the additive amount of the additive material.
When the amount is 40 parts by weight, the amount is preferably 5 parts by weight or more and 100 parts by weight or less. If it is less than 5 parts by weight, the effect of the present invention is difficult to obtain, and if it exceeds 100 parts by weight, the viscosity becomes too high when mixed with a resin, and the handleability is deteriorated.

As the base resin which constitutes the resin composition of the present invention together with the additive, a usual resin used for electric wire sealing can be used. It is desirable to use an epoxy resin or an epoxy resin obtained by improving the epoxy resin because it is particularly excellent in moldability, insulation and withstand voltage. The viscosity of the resin after the addition of the additive is preferably 100 cP or more and 5000 cP or less at 25 ° C. If it is less than 100 cP, it takes a long time to cure, and if it exceeds 5000 cP, the fluidity is lowered and the castability is remarkably lowered. When a two-component resin such as an epoxy resin is used, it is desirable that the viscosity immediately after mixing these and the additive is within the above range.

The casting of the resin composition of the present invention may be carried out using a gear pump type mixing casting machine as has been conventionally done. In this case, since the additive material is uniformly dispersed, a high effect can be obtained. However, when the casting of the resin component mixed with the additive material cannot be applied by the mixing casting machine, the additive material may be put in a casting container in advance, and the resin may be poured into the casting container and then stirred. In the latter case, care must be taken not to impair the insulation due to the presence of bubbles or the like.

[0012]

Example A bisphenol type epoxy resin mixed with additives as shown in Tables 1 and 2 was used to seal the ends of flat vinyl electric wires (11 pieces). A hard vinyl chloride resin container having an inner diameter of 6 cm, an outer diameter of 6.2 cm, and a depth of 8 cm was used as the casting container, and the end of the electric wire was sealed so as to be 0.5 cm from the bottom. The temperature inside the casting container at this time was measured by inserting a thermocouple. Each of the results is evaluated as the handling property (casting property) of each resin (excellent (it can be handled in the same way as when only epoxy resin is used),
The results are shown in Table 1 together with the good (inferior to excellent), acceptable (use of inferior handleability can be used) and poor (inferior handleability and unusable) evaluation. In the table, `` addition at the time of mixing '' refers to the case of using a resin to which an additive material has been added when casting with a mixing casting machine, and adding in a container means adding the additive material in a casting container in advance. , And shows the case where a resin is cast into it. The curing time is the value measured immediately after injection.

Regarding the resin blocks obtained by uniformly mixing and curing at the mixing ratios shown in Table 1, their volume resistivities are in accordance with JIS K6273 and their withstand voltage is JI.
It measured based on S * K6911. Further, the viscosity immediately after mixing the main agent, the curing agent and the additive was measured at 25 ° C. using a Brookfield viscometer. These results are also shown in Table 1. Further, among the glass beads used in Table 1, those having a diameter of 10 to 12 μm are EMB-20 manufactured by Toshiba Ballotini. It has a good non-oriented spherical morphology.

[0014]

[Table 1]

[0015]

[Table 2]

The effects of the present invention are clear from Tables 1 and 2. When glass beads having a diameter of 10 μm or more and 12 μm or less are used, the effect of lowering the maximum exothermic temperature is large because they are easily uniformly dispersed in the resin, and the handleability (casting property) is excellent. It should be noted that, when the addition amount is 5 parts by weight or more, the effect on the maximum exothermic temperature is observed, and when the addition amount is 25 parts by weight or more, the maximum exothermic temperature becomes 90 ° C. or less, and it is made of a hard vinyl chloride resin or polyolefin resin. A relatively inexpensive casting container can be used. In addition,
When the addition amount is 120 parts by weight, the viscosity when mixed with the resin becomes high and the handleability is slightly lowered. Thus, when glass beads having a diameter of 10 μm or more and 12 μm or less are used, judging from the balance between handleability and effect,
The resin composition shown in Example 5 in which the added amount was 50 parts by weight was the most excellent. From Table 1 and Table 2, as a characteristic of adding glass beads, as compared with the addition of silica beads, the effect of reducing the curing time is large when the same amount is added, although the exothermic temperature lowering effect is large. It turns out that it can be obtained. This is a unique effect obtained only in the system in which glass beads were added.

[0017]

The constitution of the resin composition of the present invention makes it possible to reduce heat generation during curing without requiring equipment for cooling or impairing workability and handleability. Therefore, the selection range of the material of the casting container is widened, and even when a casting container having low heat resistance is used, the product value is not impaired because defects such as deformation do not occur, and at the same time, the processing yield is high. improves.

[Brief description of drawings]

FIG. 1 is a diagram showing a state of work during casting.

[Explanation of symbols]

1 electric wire 2 resin composition 3 casting containers 4 conductors 5 joint terminals

   ─────────────────────────────────────────────────── ─── Continued front page       (56) Reference JP-A-3-296519 (JP, A)                 JP-A-3-27710 (JP, A)                 Japanese Patent Laid-Open No. 2-10614 (JP, A)                 Registered utility model 3005912 (JP, U)

Claims (5)

(57) [Claims] 1. A resin composition for electric wire sealing casting, characterized in that bead-shaped glass having a particle size of 10 μm or more and 12 μm or less is added as a non-breathable, non-hygroscopic and insulating additive. object. 2. The electric wire sealing casting according to claim 1, wherein the additive amount is 5 parts by weight or more and 100 parts by weight or less when the base resin component is 140 parts by weight. Resin composition. 3. A resin composition according to claim 1 base resin component is characterized by comprising the epoxy resin or
The resin composition for electric wire sealing casting according to claim 2 . 4. The viscosity at 25 ° C. is 100 cP or more 5
It is 0000 cP or less, The electric wire sealing casting resin composition in any one of Claim 1 thru | or 3 characterized by the above-mentioned. 5. A bead-like glass having a particle size of 10 μm or more and 12 μm or less is added to a wire sealing casting resin composition as a non-air-permeable, non-hygroscopic and insulating additive to seal a wire. A method for sealing an electric wire, which comprises: