JPH04362602A - Polymer pipe for optical fiber pneumatic delivery - Google Patents

Abstract

PURPOSE:To greatly prolong the forcible feeding length of an optical fiber unit or to drastically shorten the forcible feeding time by molding a pipe of a specific compsn. CONSTITUTION:The pipe 1 is molded of the compsn. prepd. by incorporating silicon graft polyethylene (PE) at 0.1 to 10% by weight into PE having >=0.94 density. Namely, there is a need for using a material having a low friction coefft. in order to enhance the forcible feeding characteristic and, therefore, the PEs are used by taking the mechanical characteristics into consideration. Since the high-density PE having the low friction coefft. as compared with the low-density PE among such PEs is used, the density is specified to >=0.94. Further, the friction coefft. is lowered by mixing the silicon graft PE which is a lubricant with the high-density PE which is a substrate material in order to enhance the forcible feeding characteristic of the pipe. This content is required to be set at 0.1 to 10% by the weight of the PE. The effect of the lubricant does not appear if the content is <0.1% by weight. A stable extrusion characteristic is not obtainable at the time of the extrusion molding operation of the polymer pipe if the content exceeds 10%.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer pipe for pneumatically transporting optical fibers, which is used in a method of pneumatically transporting optical fiber units into a polymer pipe that has been laid in advance.

0002

BACKGROUND OF THE INVENTION Polymer pipes used in the optical fiber pneumatic transport method are typically made of polyethylene, nylon, or the like and have an inner diameter of 6 mm and an outer diameter of 8 mm.

0003

[Problems to be Solved by the Invention] The above-mentioned polymer pipe is molded from a polymer material such as polyethylene or nylon that has as little air resistance as possible in order to send the optical fiber toward the far end using air flow pressure. There have been cases where long lengths cannot be pumped due to the coefficient of friction on the inner surface, or pumping is impossible depending on the curved part.

[0004] Furthermore, there is a problem in that the pumping speed decreases when pumping at high temperatures.

An object of the present invention is to solve the problems of the prior art as described above, and to provide an optical fiber that can significantly extend the length of the optical fiber unit or shorten the pumping time in the optical fiber pneumatic transport method. An object of the present invention is to provide a polymer pipe for pneumatic conveyance.

[0006]

[Means for Solving the Problem] As a result of conducting various research and development based on the knowledge regarding polymer pipes used in the optical fiber pneumatic transport method, the present inventors found that a lubricant was added to polyethylene as a material for the polymer pipe used in the optical fiber pneumatic transport method. We have discovered that by containing silicone-grafted polyethylene, it is possible to obtain a pipe that can significantly extend the pumping length of the optical fiber unit or significantly shorten the pumping time, and have completed the present invention. be.

That is, the polymer pipe for optical fiber pneumatic transport of the present invention has a weight ratio of silicon grafted polyethylene to polyethylene having a density of 0.94 or more from 0.1 to 10.
A pipe is formed by molding a composition containing %. It is also preferred that the outer surface of the pipe be coated with a polymer sheath or a flame retardant material.

[0008] The polymer pipe for optical fiber pneumatic transport uses polyethylene (PE) having a density of 0.94 or more as a base material. In order to improve the pumping characteristics, it is necessary to use a material with a low coefficient of friction. Therefore, PE is used in consideration of its mechanical properties, and among these, high-density PE, which has a lower coefficient of friction than low-density PE, is used. Therefore, the density is 0.9
It was set as 4 or more.

[0009] In order to further improve the pumping characteristics of the pipe,
The coefficient of friction was lowered by mixing silicone-grafted polyethylene, a lubricant, with the high-density PE base material. This content needs to be 0.1 to 10% by weight relative to polyethylene; if the content is less than 0.1% by weight, the lubricant effect will not appear, and if it exceeds 10%, the polymer pipe Stable extrudability cannot be obtained during extrusion molding operations.

0010

[Operation] By molding a pipe with a composition containing 0.1 to 10% by weight of silicon grafted polyethylene in polyethylene with a density of 0.94 or more, the coefficient of friction of the molded pipe is higher than that of conventional pipes. It gets lower. Therefore, by using this pipe in the optical fiber pneumatic feeding method, it is possible to significantly extend the pumping length of the optical fiber unit in that method, or to significantly shorten the pumping time.

[0011] Furthermore, by covering the outer surface of the pipe with a polymer sheath, the pipe is mechanically protected. Furthermore, by coating the outer surface of the pipe with a flame-retardant material, the pipe is protected from fire and the like.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings.

[0013] High-density polyethylene with a density of 0.942 and silicone grafted polyethylene were mixed in a weight ratio of 49:1 (
A pipe (inner diameter: 6 mm, outer diameter: 8 mm) 1 was formed using this composition as a material as shown in FIG. 1, and this was used as a sample (pipe A). Further, a pipe was formed using high-density polyethylene having a density of 0.942 in substantially the same manner as described above, and this was used as a sample (pipe B).

The friction coefficient and pumping time of these samples (pipes A and B) were measured, and the results are shown in Table 1.

[0015] Each measurement method is as follows.

[0016] The coefficient of friction is determined by
An optical fiber unit 6 in which a plurality of optical fiber cores 2 and tear strings 3 as shown in FIG. 2 are coated with PEF5 is inserted through nylon 4, and this is wound around a tube 7 as shown in FIG. Add a weight W to one end of the optical fiber unit 6,
From this, the coefficient of friction was determined using Equation 1 below. In the figure,
8 indicates a pulley.

μ=(1/θ)ln(TA/TB)...Equation 1(μ
: Friction coefficient, θ (rad): Pipe bending angle, TA (
kgf): Pulling force, TB (kgf): Back tension) The pressure feeding time is the length wound on a drum with a body diameter of 1000 mm.
Place a 500 mm sample in a thermostatic chamber and leave it for more than 10 hours.
While the temperature of this sample was stable, the optical fiber unit was pumped to determine the pumping time, and the relationship between the pipe length (m) and the pumping time at this time is shown in FIG. At this time, the temperature of the constant temperature bath was 20°C (room temperature) and 70°C.

[0018]

[Table 1]

As is clear from the results shown in Table 1,
The sample of pipe A of the present invention had a lower friction coefficient and shorter pumping time than pipe B. In addition, as shown in Figure 4, pipe A has a constant temperature bath temperature of 20°C and 70°C.
It was found that there was almost no difference in temperature.

[0020] Therefore, by molding a pipe from a composition containing polyethylene with a density of 0.94 or higher and a specified amount of silicone grafted polyethylene, the coefficient of friction on the inner surface of the molded pipe can be lowered than before. . Therefore, by using this pipe in the optical fiber pneumatic feeding method, the length of the optical fiber unit in the method can be significantly increased, or the time required for pumping can be significantly shortened. In addition, the polymer pipe 1 of the present invention can perform pressure feeding at high temperatures without the pumping speed decreasing much compared to room temperature.

Furthermore, the outer surface of the pipe is covered with a polymer sheath. As a result, the pipe is covered with the polymer sheath, so that the pipe can be mechanically protected, and the optical fiber unit and the like inside the pipe are also protected.

Furthermore, the outer surface of the pipe is coated with a flame-retardant material. As a result, the pipe is covered with a flame-retardant material, so even if a fire or the like occurs, the pipe will hardly catch fire. For this reason, contagious fires and the like occurring through the pipe are prevented, and the optical fiber unit and the like within the pipe are also protected from fire.

[0023]

Effects of the Invention In summary, according to the present invention, the density is 0.
．． Since the pipe was molded from a composition containing 0.1 to 10% by weight of silicone-grafted polyethylene in polyethylene of 94 or higher, in the optical fiber pneumatic feeding method,
The pumping length of the optical fiber unit can be significantly increased or the pumping time can be significantly shortened. In addition, by coating the outer surface of the pipe with a polymer sheath, it is possible to mechanically protect the pipe, and by coating the outer surface of the pipe with a flame-retardant material, it has the excellent effect of protecting the pipe from fire, etc. do.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a polymer pipe of the present invention.

FIG. 2 is a cross-sectional view showing an example of an optical fiber unit that is pumped into a polymer pipe.

FIG. 3 is a diagram showing a method for measuring the coefficient of friction of a pipe.

FIG. 4 is a diagram showing the relationship between pumping time and pumping characteristics.

[Explanation of symbols]

1 Pipe

Claims (3)

[Claims] Claim 1: Polyethylene with a density of 0.94 or more and silicone grafted polyethylene at a weight ratio of 0.1 to 10.
A polymer pipe for optical fiber pneumatic transport, characterized in that the pipe is molded from a composition containing %. 2. The polymer pipe for pneumatic optical fiber transport according to claim 1, wherein the outer surface of the pipe is covered with a polymer sheath. 3. The polymer pipe for optical fiber pneumatic transport according to claim 1, wherein the outer surface of the pipe is coated with a flame-retardant material.