JPH01303010A - Cable joint or terminal - Google Patents

Abstract

PURPOSE:To improve mantle/dismantle performance and water tightness, by employing a two liquid mixture normal temperature setting polyurethane resin mainly composed of liquid polybutadiene polyol and non-aromatic polyisocyanate as a compound and containing 20wt.% or more of oil. CONSTITUTION:A polyurethane series compound 1 to be employed is composed of two of liquids containing polyol and polyisocyanate as essential components. The compound is mixed immediately before usage and injected through an injection port 8, where liquid polybutadiene polyol is employed as the polyol while a non-aromatic polyisocyanate is employed as the polyisocyanate. Furthermore, 20wt.% or more of oil exhibiting volume resistivity higher than 5X10<13>OMEGA-cm for the temperature higher than 20 deg.C is contained in the component 1 in order to satisfy both the electric insulation and dismantling performance.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cable connection section or a terminal section, and more specifically, to a compound-filled type of communication cable or optical fiber cable that has excellent watertightness and disassembly workability. Relating to cable connections or terminals.

[Prior Art and Problems to be Solved by the Invention] It is common practice to fill the gap between the case and the core wire with a compound to create a watertight structure at the connection or terminal portion of a communication cable or optical fiber cable. It is being carried out on a regular basis. For these types of cable connections or terminals, cold-curing resins such as epoxy, polyester, or polyurethane are used as filling compounds, or conventionally known compounds are made of tough hardening resins. Therefore, if you want to disassemble the connection part or terminal part and reconnect the cable at a later date, it will be impossible to do so without damaging the cable. Recently, the development of a silicone resin that hardens into a shell shape as a disassemblable compound has been progressing.Is it possible to solve the problem of disassembly by using this type of silicone compound? It is difficult to put it into practical use widely for several reasons.

The present invention has been made in view of the above points, and an object of the present invention is to provide a cable connection section and a cable terminal section that are excellent in ease of installation, ease of construction, and ease of disassembly.

[Means for Solving the Problems] The present invention provides a cable connecting portion and an end portion formed by filling a gap between a sleeve and a cable with a combination 1 to 1. A two-component mixed room-temperature curable polyurethane resin containing as main components and a non-aromatic polyisocyanate is used, and this compound has a volume resistivity of 5 x 101:lΩ-cm or more at 20°C.
It is a cable connection part or terminal part characterized by having two people with a weight of 0% by weight or less.

[Example] The cable connection part or terminal part of the present invention is filled with a polyurethane compound having a particularly limited composition. This is based on the maintenance of watertight insulation properties of the cable and the ease of dismantling the cable to enable reconnection by disassembling the cable connection or terminal section as necessary. That is, conventionally used epoxy resin systems and polyester resin systems have high mechanical strength, and if the formulation is formulated to lower the mechanical strength to a level that allows disassembly, curing will be significantly delayed. And the cured product is prone to cracks.
It is known that there are drawbacks such as low electrical insulation properties, and the performance aimed at by the present invention cannot be satisfied. Therefore, by researching various formulations of polyurethane and using a compound whose composition was specified, the cable connection part or terminal part of the present invention was completed.

The polyurethane compound used in the cable connection or terminal part of this invention consists of two liquids each containing polyol and polyincyanate as essential components, and is mixed immediately before use and filled from the injection port.Liquid polybutadiene is used as the polyol. Polyols, polyisocyanes 1-1 and non-aromatic polyisocyanes 1-1 are used. As the polyol, a liquid polybutadiene polyol is mainly used, or a polyether triol prepared by adding propylene oxy-1 to hydrogenated polybutadiene polyol, castor oil, polypropylene glycol, or chrycerin within a range that satisfies the purpose of this invention. Volite 1
Heramethylene ether glycol, polycaprolactone-based polyester polyol, etc. may be used. Examples of non-aromatic polyisocyanates include hexamethylene diisocyanate and its trimer, infusyl isocyanate, and lysine triincyanate. -1, etc. can be mentioned,
Prepolymer incyanates of these and polyols can also be used. The cable connection part and the terminal part of this invention can be disassembled without damaging the cable if necessary, so it is possible to disassemble the cable without damaging the cable. The compound must be sufficiently transparent to allow for clear visualization of the conductor position in addition to careful disassembly. Tolylene diisocyanate (T
DI), Cyphenylmethanecyisocyanate-1~(MDI
) are the most commonly used aromatic compounds, but these have some difficulty in compatibility with ordinary polyols, and tend to lose the transparency of the cured product or become hard and tough. Therefore, it is not suitable for use as polyurethane to be filled in the cable connection part or terminal part of the present invention.

Furthermore, in order to achieve both electrical insulation and disassembly properties, the cable connection or terminal part of the present invention contains 20% by weight of oil with a volume resistivity of 5 x 1213 Ω-cm or less at a temperature of 20°C or higher. It is constructed by filling polyurethane comparans 1 to 1 which are made to contain the following to provide a volume resistivity of 5 xio'' Ω-cm or more even after injection hardening.

Does the addition of oil reduce the initial viscosity of Combalan 1 and the strength of the cured product, and is it effective in improving the workability of injection into the sleeve and the workability of dismantling?20% or more is not added to this invention. is insufficient to reach the target performance.

Specific examples of oils suitable for blending into the polyurethane compound used for the cable connection or terminal portion of this invention include mineral oil, alkylhensen, alkylnaphthalene, and alkyldiphenylmethane listed in the JIS C2320 electrical insulation oil standard. Other examples include process oil, which is used as a rubber operating agent. Refined soybean oil and linseed oil are also suitable;
It may be used alone or in combination with the above oils.

Phthalate esters, phosphate esters, etc., which are commonly used as plasticizers for polyvinyl chloride, have insufficient volume resistivity, so they are not suitable for adding to the compound used for the cable connections or terminals of this invention. do not have. The ratio of liquid polybutadiene polyol to non-aromatic polyisocyanate is the ratio of OH groups to NGO groups, or 0.8 to 1.
It is reasonable to crawl out of the range of 2. If less polyisocyanate is used, the strength of the cured product will decrease, making it easier to dismantle, or the number of residual OH groups will increase, reducing water resistance and electrical insulation properties, so it is necessary to reduce the amount of polyisocyanate. be.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the cable connection portion or terminal portion of the present invention will be specifically described based on the drawings.

FIG. 1 is a partially cutaway side view showing the configuration of a communication cable connection section to which the present invention is applied.

A pair of plastic sleeves 5 formed to fit in the center of the cable connection part IO are inserted in advance into two cables to be connected, and the cable core wires 2 from the left and right are connected to the center part of the connection part 3. Sealink compound 4 is applied to prevent the polyurethane compound 1 filled in the sleeve 5 from flowing into the cable. Next, the plastic sleeve 5 is shifted and fitted from the left and right so as to cover the connection portion. Sealink tape 7 is placed on the fitting part of the sleeve 5 and the lap part with the cable sheath 6.
roll. Finally, the identified polyurethane compound l
is filled from the inlet, and a stopper 9 is attached to the inlet 8 to constitute the cable connection part of the present invention.

Figure 2 shows a communication cable terminal section 2 to which this invention is applied.
FIG. First, after sealing the gap between the cable core wire 12 and the cable sheath 16 by applying the sealing compound 4, the plastic sleeve 15 is set on the cable sheath 16 as shown in FIG. Wrap and secure. Next, the specified polyurethane compound 1 is injected from the end to form the cable end of the present invention.

Next, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Example 1 LAP sheath communication communication two full with external diameter of 23 mm mφ,
After connecting the two pieces of wood (9mm
VC) plastic sleeve 5 (external diameter 60mmφ x
(Length: 700 mm x Thickness: 5 mm) were fitted and assembled, and the sleeves and the lap portion of the sleeve and cable sheath were wrapped with sealing tape 7 for sealing. In order to facilitate disassembly, a silicone mold release agent was applied thinly to the inner surface of the plastic sleeve.

Finally, polyurethane compaction I-' 1 having the composition shown in Example 1 in Table 1 was injected and filled, and a stopper 9 was attached to form the cable connection part 10 of the present invention. □The details of the test method for confirming the performance of the cable connection part of this invention are shown in FIGS. 3 and 4. That is, as shown in Fig. 3, the insulation resistance between the wire cores is determined by immersing the cable connection part in water W in the container 30, and measuring the value for 1 minute at 500 VDC with a super megohmmeter (not shown) between all the wire cores. It measures about. The initial insulation resistance was measured immediately after immersion in water, and then in order to confirm the watertight insulation of the connection, the plug 9 of the inlet 8 was removed and the water was immersed in water W at a temperature of 50'C as shown in Figure 3. Measure the change in insulation resistance between the core wires.

FIG. 4 shows a situation in which a vibration test is carried out in consideration of the vibrations applied to the cable connection part in the installed state. The cable connection part 10 supports a position of 500 mm from both ends.
'40 held fixed, amplitude ±1 in the center of the connecting sleeve
0mm, 1OHz vibration part V vertically l x l
After applying 06 vibrations (1 million times), the test piece was immersed in water as shown in Figure 3 at a temperature of 50°C for 30 days to measure oral changes, and the insulation resistance between the core wires was measured.

Disassembly workability is to judge the ease of work when removing the connecting sleeve 7 and cutting the filled comparators 1~ from the core wire. It can be removed by simply tearing it off or using a tool without damaging the core wire.

It was confirmed that the polyurethane compound shown in Example 1 in Table 1 has excellent watertight insulation and vibration resistance, and that the Combalun 1- can be easily dismantled and removed without using tools.

Example 2. Example 3 Polyurethane compound filled into the connecting sleeve
A cable connection portion was assembled in exactly the same manner as in Example 1, except that the compositions were changed to those shown in Example 2 and Example 3 in Table 1. Table 1 shows the properties of the compound and the results of the cable connection performance test. From this table, watertight insulation, vibration resistance, and disassembly were all good.

Comparative Example 1.2.3 Polyurethane Comparan 1 to be filled in the connecting sleeve
A cable connection portion was assembled in exactly the same manner as in Example 1 above, except that the composition of Example 1 was changed to the compositions shown in Comparative Examples 1 to 3 in Table 1, respectively. The insulation resistance between the core wires of the joints using Combalan I with the compositions of Comparative Examples 1 and 3 was initially 3 to 4 orders of magnitude lower than that of Examples 1 to 3, and in Comparative Example 3, the temperature was 50'C. After being immersed in water for 90 days, the super insulating material decreased to an unmeasurable value (less than 6 Ω), and in Comparative Example 1 it decreased to 6×10 6 Ω, indicating that the reliability of the watertight insulation was insufficient. Ta. The compounds of Comparative Examples 2 and 3 were opaque, and it was difficult to remove the compounds without damaging the core wires even if a tool was used when disassembling the joints.

(Blank below) [Effects of the Invention] As explained above, the cable connection part or terminal part of the present invention has good watertight insulation and vibration resistance, and can be easily disassembled and reconnected with the compound, making it suitable for industrial use. Its utility value is extremely high.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views showing the cable connection and the terminal to which the present invention is applied, Figure 3 is a side view of a test device for watertight insulation of the connection, and Figure 4 is the connection. FIG. l...Polyurethane compound 2...Cable core 3...Cable core connection part 4...Sea link compound 5...Plastic sleeve 6-...Cable sheath 7. ... Sealink tape 8 ... Inlet port 9 ... Stopper

Claims (1)

[Claims] In the cable connection part and terminal part formed by filling a compound into the gap between the sleeve and the cable, the compound is composed of two compounds each containing liquid polybutadiene polyol and non-aromatic polyisocyanate as main components. A cable that uses a liquid-mixed room-temperature curable polyurethane resin, and that the compound contains 20% by weight or more of oil having a volume resistivity of 5 x 10^1^3 Ω-cm or more at a temperature of 20°C. Connection or terminal.