JPS62220555A - Sheet for molding mechanical closure case of cable - Google Patents

Abstract

PURPOSE:The titled, sheet, consisting of a resin component consisting essentially of a specific amount of a thrmoplastic resin, ammonium polyphosphate, etc., and a specified amount of glass fibers, having flame retardancy without emitting noxious halogen gases and suitable for mechanical joints of cables. CONSTITUTION:A sheet, consisting of (A) 70-35wt% thermoplastic resin, e.g. polyethylene, etc., (B) 5-25wt% ammonium polyphosphate, (C) 5-35wt% fine powdery melamine resin having <=10mu particle diameter, (D) 5-15wt% talc and (E) 17-25wt% glass fibers having 25muphi diameter and produced by coextruding a mat produced from the above-mentioned glass fibers and the resin and melt integrating the mat with the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a case for use in mechanical joints of cables, in particular mechanical joints which do not generate harmful halogen gas f:R.

Conventional technology There are various methods for connecting cables such as communication cables, but this method is attracting attention because it is assembled mechanically using a mechanical closure and is assembled using bolts and nuts without using a torch. It's starting to happen.

For this purpose, the cable mechanical joint construction method has attracted attention, and a nonflammable and durable plastic case is required as the closure case used for this method.

However, to make the case material used here nonflammable, halogen-based flame retardants are usually added to the plastic, or aluminum hydroxide or magnesium hydroxide is added to the plastic, and to further increase mechanical strength, glass fiber is added. It is considered that the mixture of

However, when a chlorine-based flame retardant is blended into plastic, it has the disadvantage of generating toxic gas when burned, and when it is blended with ice hydroxide, aluminum magnesium hydroxide, etc., it inhibits the wettability of plastic bottoms and glass fibers. However, it must be said that this case has a serious drawback as a case for a closure, which should be airtight in order to create an air flow path.

Means for Solving the Problems The present invention has been made as a result of intensive research to solve the above problems, and the outline thereof is as follows.

This is a sheet for the bottom shape of a mechanical closure case, which is mainly composed of a thermoplastic resin, ammonium polyphosphate or phosphoric acid ester, and finely powdered melamine resin, and is made by completely dispersing lass fibers therein. Further details of the preferred formulation are as follows.

Thermoplastic resin is the basic material for the sheet for the case bottom shape, and in general, those that are low cost and easy to process are selected. Therefore, polyethylene, polypropylene, ethylene propylene copolymer, etc. are preferable for this purpose, and vinyl chloride resins are not particularly preferable because they generate chlorine in the event of a fire.

If the thermoplastic resin exceeds 70% by weight, the amount of other compounding ingredients becomes too small, resulting in a decrease in flame retardant effect and a decrease in mechanical strength. If the weight is less than 35 fgq6, the processability will be poor and it will be unsuitable for sheet formation.

Ammonium polyphosphate or phosphate ester is a non-halogen flame retardant and has good wettability with glass fibers.
Therefore, a sufficient flame retardant effect can be imparted to the sheet.

If it is less than 5'Mkcs, the effect is insufficient, and 25
If it exceeds the weight percentage, it will contain an excessive amount of the compound t which has nothing to do with improving the flammability, increasing the cost and impairing the flexibility of the case.

For example, fine powder melamine resin of 10μ or less is preferable because it is easily dispersed, and the N component in the molecule exhibits a flame retardant effect even when exposed to flame, and the phosphoric acid compound and melamine resin are compatible. It is recognized that the residual effect increases the dynamic and combustion effect.

Next, talc contributes to weight increase and processing during case manufacturing.

Glass fiber is commonly used to strengthen plastics25
It is preferable to mix 17 to 25 folds of about .mu.φ because this increases the mechanical strength while maintaining the flexibility of the sheet. If the weight is less than 17 g's, the effect will be insufficient, and if it exceeds 25 g's, the amount of glass fiber will increase unnecessarily.

Next, typical examples of sheet manufacturing means will be described.

1) Manufacture of glass fiber//- A glass fiber//'e23μΦ is produced by spinning, and then surface treated with a silane surface treatment agent to activate the surface.

It is better to carry out silane-based surface treatment in an oxide-rich manner than in the case of ordinary glass fibers.

Seventy of the surface-treated glass fibers are twisted or converged and wound onto a reel.

11) Manufacture of glass fiber mats As shown in Fig. 1, one glass fiber/coo 23 μφ x 0 reel is housed in one 30 reels, and the glass fiber/mat is made up of 4 units. - Prepare a feeding machine IO. On the other hand, while rotating the conveyor 11, the glass fiber/Xi coil is placed on top of the conveyor if
The material is uniformly dropped onto the top, made into a mat, punched and cut with a kneeler 12, and the mat 14 is wound up with a take-up reel 13.

The state of the mat 14 thus produced is as shown in the top view of FIG.

li+) Production of Sheet As shown in FIG. 3, for example, polypropylene 16 is extruded into a sheet by an extruder 15, and at the same time, the glass fiber produced in 11) is produced. - Pine) 14 is supplied from both the upper and lower surfaces, and a polypropylene/film 17') having a thickness of 0.5+U+A degrees is supplied from the outside, and then enters the laminator. The laminator consists of a pair of steel pels 18 with a thickness of 2 to 3 μm, which are sandwiched from above and below to process and adhere. Pressure was applied at approximately 5 Ky/crn2, and the upper steel belt was heated at the heating section 19 at the beginning and at the cooling section 20 at the rear.

In the heating section, the resin is heated to about 350°C, and the sandwich-shaped pieces are melted and integrated with the resin, and then solidified by cooling.

Thereafter, the sheet is cut into a predetermined length by a cutter 21 when it comes out of the laminator in the direction of travel to obtain a sheet.

The resin used here is of course not limited to polypropylene, but it is preferable to use a resin with a small H and MI of 2 to 3 to be fed to the extruder. This is because if J is too large, the resin will enter only the surface of each strand of the glass mat.

Further, the sheet according to the present invention is heated and deformed to easily form a hollow tubular body (a casen for a mechanical closure of a cable).

Next, a prototype test example for confirming the performance of the sheet according to the present invention will be described.

A sealed case made of a fireproof sheet (thickness 5 to 6 U) manufactured with the composition shown in Test 1, Example As a result of observing the leakage underwater, there was no leakage.

Test 2. A sealed case made of a fireproof sheet (thickness 5 to 6 m) was prepared using the composition shown in the example, and air (t, oh/cm2) was introduced into the case.
While continuously monitoring the internal pressure, heat cycle (-20
As a result of applying 50 cycles (~+60°C, 2 cycles/day), almost no leakage was observed, and no leakage in water was observed.

Test 3: A sheet 23 with a thickness of 5 mm was prepared as shown in FIG.
0 ms, a hole 22a of 811jφ in the center, and a hole 2゛2b in the thickness direction of the sheet as shown in Fig. 5.
A metal pipe 24 having a diameter of 4K II was fitted into the hole 22a of the sheet 23, and its tip was sealed, and the pipe was placed in a water tank 25 and air (4KII/cm23) was flowed in the direction of the arrow to observe leakage in the water. No leakage from the surface or cross section of the sheet was observed.

Each of the sample sheets of Examples 1.2 and 3 was heated with a torch lamp for 3 minutes and then the flame was removed, and the fire extinguished within 5 seconds.

Effects of the Invention According to the present invention, as is clear from the above test examples, it does not contain components that generate toxic gas in the event of a fire, is safe even in the event of a fire, and is flame retardant and has excellent fire extinguishing ability. The glass fiber in the sheet has good wettability with the blended resin, so no air passages are created in the sheet.
From this point of view as well, it complements both waterproofness and flame retardancy.

Furthermore, this sheet can be easily shaped into a case that can withstand the necessary internal pressure, and is very effective for cases for closures of mechanical joints of cables.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the manufacturing process of the glass mat, Fig. 2 is a top view showing an example of the glass mat, Fig. 3 is an explanatory diagram showing an example of the manufacturing process of the sheet of the present invention, and Fig. 4 is an illustration of the test sample. A perspective view showing the shape, and FIG. 5 a cross-sectional view showing the test state. Engineering...Glass Fiber/T-, 10...Glass Fiber/Mer feeding machine, 11...Conveyor, 12...Knee?
Ra 1 work 3...take-up reel, work 4...mat, 1
5... Extruder, 16... Polypropylene, 17...
・Polyp tetrapyrene film, 18... Steel belt, 19... Heating section, 20... Cooling section, 21... Cutter, 22... Hole, 23... Sheet, 24...
Metal pipe, 25...Aquarium. Agent Patent Attorney Mamoru Takeuchi Figure 1

Claims (2)

[Claims] (1) For molding a mechanical closure case for a cable, characterized in that glass fibers are dispersed in a sheet of a composition mainly consisting of a thermoplastic resin, ammonium polyphosphate or phosphate ester, and finely powdered melamine resin. sheet (2) 70-35% by weight of thermoplastic resin, 5-25% by weight of ammonium polyphosphate or phosphate ester, 5-35% by weight of fine powder melamine resin, 5-15% by weight of talc, and 17-25% by weight of glass fiber. A sheet for forming a mechanical closure case for a cable according to claim 1 consisting of