JP2000119605A - Wiring fixation tape for confirming laying position of gas tube made of polyethylene and preparation of film for tape using polyethylene gas-tube waste material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring fixation tape for confirming the laying position of a gas tube made of polyethylene to make effective use of polyethylene gas- tube waste materials. SOLUTION: This wiring fixation tape for confirming the laying position of a gas tube made of polyethylene is prepared by forming an adhesive layer on one side of a tape prepared by molding a mixture of polyethylene gas-tube waste materials and a low-density polyethylene. Here, the low-density polyethylene content in the mixture is from 2 to 20 wt.%. A preparation process of a film for tapes using polyethylene gas-tube waste materials is a process wherein a mixture of polyethylene gas-tube waste materials and a low-density polyethylene is molded into a film through blown-film extrusion. Here, the mixture is molded into a film so that a film having a thickness of about 80 μm exerts an Elmendorf tear strength (TRMD) in the take-off direction of from 5 to 30% of the tear strength (TRTD) in the direction vertical to the take-off direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the effective use of the end of a polyethylene pipe, which is a waste material in the burying work of a polyethylene gas pipe, and more particularly to a mixture of a waste material of a polyethylene gas pipe and low-density polyethylene. The present invention relates to a method for manufacturing a tape for fixing a wiring for confirming a burying position of a polyethylene gas pipe formed into a tape and having an adhesive layer on one surface, and a film for a tape.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of measures against rust of gas pipes and the like buried underground and measures against breakage during an earthquake, it has recently been made durable without rust and has excellent strength characteristics. There has been an increasing tendency to use pipes instead of iron gas pipes.

In the burial work of gas pipes, since the ends of the polyethylene gas pipes are cut so as to have a required size according to the topography of each construction site, these ends are generated in large quantities as waste materials. . Usually, these waste materials are accumulated and incinerated or crushed and landfilled, hardly reused, and wastefully disposed of without effective use of resources.

[0004]

In view of the above situation, the present inventors have studied diligently to effectively use the waste gas pipe made of polyethylene, and in the case of a film formed only of the waste gas pipe made of polyethylene, the tape is placed at the same position. There is no problem when simply wrapping it around. However, in the case where the winding portions are shifted slightly one after another and overlapped and spirally wound, the shifted portions float up and do not adhere to each other to form a gap (usually referred to as “slack”), and are used as a tape. It was a hindrance to practical use. In order to solve the above-mentioned problems, the present inventors have studied and made a mixture of waste gas pipe made of polyethylene and ethylene-vinyl acetate copolymer or ethylene-ethyl acrylate copolymer by a T-die method (inflation method). It was found that the above-mentioned problems could be solved by a tape formed of this film, and this tape was laid along the longitudinal direction of the polyethylene gas pipe on the gas pipe in order to confirm the embedment position. It is proposed to use it as an adhesive tape to fix the electric wire.

[0005] Although this tape has less strength change due to temperature and humidity than a conventional vinyl chloride resin insulating tape and has excellent strength characteristics, its winding property around the gas pipe is low. Although slightly inferior to tape, it was not a problem. However, it is required that the above-mentioned tape (having a thickness of about 50 to 150 μm) can be cut easily by pulling the tape by hand without using a cutting tool such as a knife after winding the tape. Needed improvement. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a tape for fixing a position of a polyethylene gas pipe, which can be easily cut by pulling by hand, using a waste material of the polyethylene gas pipe.

[0006]

The object of the present invention is achieved by the following inventions. That is, the present invention is characterized in that an adhesive layer is formed on one surface of a tape obtained by molding a mixture of waste material of polyethylene gas pipe and low-density polyethylene, and the position of the polyethylene gas pipe is confirmed. Tear strength (TR _MD ) in the take-off direction of a film having a thickness of about 80 μm in a method of forming a film of a mixture of waste tape of wiring fixing tape and waste gas of a polyethylene gas pipe and low-density polyethylene by an inflation method.
Is 5 to 3 of the tear strength (TR _TD ) in a direction perpendicular to the direction.
A method for producing a film for tape using waste gas pipe made of polyethylene, characterized by forming a film so as to have a concentration of 0%.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to embodiments of the present invention. The waste material of the polyethylene gas pipe (hereinafter sometimes referred to as a polyethylene pipe or a PE pipe) used in the present invention is, when burying the polyethylene pipe, its end is cut for length adjustment or the like,
Usually, it is disposed of as unnecessary material, but the cut end tube portion is mainly used. Polyethylene pipes are not exactly known because the city gas company did not disclose their names, but it appears that medium density polyethylene is mainly used. The polyethylene pipe is usually colored light green or the like.

[0008] Usually, the collected PE pipe waste is pulverized by a suitable means after washing, and then, for example, 170 pulverized.
It is pelletized at a temperature of about 200 ° C. or the like by an extruder or a pelletizer and used. In the present invention, the low-density polyethylene mixed with the waste polyethylene pipe includes low-density PE (LDPE) produced by a high-pressure method and linear low-density PE [LLDPE (linear low-density polyethylen) produced by a low-pressure method.
e) are included. The ratio of the low-density polyethylene in the mixture of the PE pipe waste material and the low-density polyethylene is preferably 5 to 20% by weight, more preferably 5 to 1% by weight.
5% by weight. If the amount is less than 5% by weight, the film forming property is not sufficient, and it is difficult to cut the obtained tape by pulling it by hand. If it exceeds 20% by weight, it is not economical and is not preferable.

The waste polyethylene pipe and the low-density polyethylene can be mixed using a conventional mixer, and the mixing method is not particularly limited. In preparing the mixture, additives such as a coloring agent, an antistatic agent, an antioxidant, and a processing aid can be appropriately added as needed. The low-density polyethylene is preferably used as a masterbatch containing pigments and other additives.

In the present invention, a mixture of waste polyethylene pipe and low-density polyethylene is used.
A film of 50 μm, preferably 80-120 μm is made. At that time, the Elmendorf tear strength (TR _MD ) in the take-off direction of the formed film is 5 to 30%, preferably 5 to 20% of the tear strength (TR _TD ) in the direction perpendicular to the direction.
It is necessary to form a film so that When the ratio is smaller than the above range, the tape is easily cut, and when the ratio is larger than the above range, it is difficult to cut the tape by hand. Here, the Elmendorf tear strength (TR _MD ) in the film take-off direction refers to the tear strength of a test piece taken in the longitudinal direction of the film, and the tear strength (TR _TD ) in a direction perpendicular to the direction. Means the tear strength of a test piece taken in the transverse direction of the film. The test method is JIS K7128
Obey.

Normally, when PE is formed into a film by the inflation method, the temperature of the molten PE at the exit of the die is from 180 to
190 ° C, cooling rate is 30H for inverter cycle
_Z or less, take-off speed is 20-40 m / min, BUR (blow
up ratio: the ratio of the diameter of the mold to the diameter of the film when it is an inflation film) is 1.5 to 2.5. A film in which the tear strength (TR _MD ) of the resulting film falls within the above range can be produced by adjusting the above molding conditions. For example, if the temperature is 210
° C., the cooling rate 35~40H _Z, a take-up speed of 15 m /
Although it can be obtained by forming the film into minutes, it is not limited to these conditions.

Next, the obtained film is cut into an appropriate width (usually 5 cm), and at least one surface of the film is subjected to a surface treatment by a known method such as corona discharge treatment or chemical treatment. An adhesive is applied to form an adhesive layer. In the present invention, any of the pressure-sensitive adhesives conventionally used for tapes can be used, and the type of the pressure-sensitive adhesive is not particularly limited. Rubber-based adhesives are preferred. Before or after the surface treatment, patterns, characters, and the like can be printed on the other surface of the film, if necessary.

The tape on which the pressure-sensitive adhesive layer is formed is wound up, and the film is cut into the above-mentioned width to obtain the tape of the present invention. The tape thus obtained is provided with a locating wire that is wired along the gas pipe when the gas pipe is buried in order to detect the buried position of the gas pipe when the buried polyethylene gas pipe is re-excavated. It is used to secure the so-called coated electric wire to the gas pipe. The buried position of the gas pipe can be specified by applying a voltage from one place to the wiring and detecting electromagnetic waves radiated from the wiring on the ground surface.

[0014]

Next, the present invention will be described more specifically with reference to examples and comparative examples. Example 1 90 parts by weight of a waste gas of a Tokyo gas light blue colored polyethylene gas pipe processed into a pellet and low density polyethylene (UF421 manufactured by Nippon Polychem) colored blue with a pigment (Pigment content: 5% by weight) 10 parts and an antistatic agent (LXAS manufactured by Nippon Polychem Co., Ltd.) were melt-mixed in an extruder to prepare pellets of the mixture.

The temperature of the molten mixture at the outlet of the inflation die is about 210 ° C. by using an inflation film forming machine (screw diameter: 65 mm, die diameter: 400 mm, resin extrusion rate: 100 kg / hour).
Become so extruded molten mixture from an inflation die, cooling rate 40H _Z, take-up speed 15 m / min, BUR
An inflation film having a thickness of about 80 μm was formed under the molding conditions of 2.07.

From the obtained film, test pieces are cut in parallel to the take-off direction (longitudinal direction of the film) (MD) and perpendicularly (transverse direction of the film) (TD).
Elmendorf tear strength was measured according to ISK7128. Table 1 shows the results. Further, one surface of the film was subjected to corona discharge treatment, and a rubber-based pressure-sensitive adhesive was applied to the treated surface using a roll coater to form a pressure-sensitive adhesive layer. This film was wound up on a paper roll core and cut into 5 cm width to obtain a tape for fixing the wiring for confirming the embedded position of the polyethylene gas pipe.

Comparative Example 1 A film having a thickness of about 8 was obtained in the same manner as in Example 1 except that the molding conditions of the blown film molding machine were as follows.
A 0 μm blown film was produced, and a tape using the film was produced. Elmendorf tear strength (TR _MD and TR _TD ) of the film in the same manner as in Example 1.
Was measured. The results are shown in Table 1. Temperature at the exit of the die of the molten mixture: 190 ° C. Cooling speed: 20H _Z take-off speed: 25 m / min BPR: 2.07

Table 1

Using the two types of tapes of Example 1 and Comparative Example 1, it was determined whether or not a covered wire having a diameter of about 10 mm, which was wired along a polyethylene gas pipe (outer diameter 15 cm), could be fixed with a width of about 15 cm. confirmed. Both tapes had no problem with the adhesiveness to the gas pipe. Also, there was no particular problem in the fluctuation of strength due to humidity and temperature change. These tapes have moderate flexibility and flexibility, and can be wound spirally along the circumference of the gas pipe, just like conventional vinyl chloride resin tapes, and fix the wires with a width of 15 cm. Was completed. At that time, there was no "slack" in the rewinding portion of the tape (the portion where the electric wire is present and the target portion), and the tape and the gas pipe were in close contact. After fixing the electric wire, the tape was stretched and cut. However, it was confirmed that the tape of Example 1 could be cut without any problem and that the tape could be used without any trouble at the burial site. However, it was confirmed that the tape of Comparative Example 1 could not be cut, which hindered use at the burying site.

[0020]

As described above, according to the present invention, a tape having excellent strength characteristics and flexibility and flexibility can be obtained. The tape is closely wound on a gas pipe having a large outer diameter and wound in a spiral shape along the circumference. The present invention provides a wiring fixing tape for confirming a buried position of a polyethylene gas pipe having excellent workability, which can be stretched and cut by hand without using a tool such as a knife. According to the present invention, it is possible to effectively use waste materials of polyethylene gas pipes, and the present invention greatly contributes to effective use of resources.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Keizo Kase 4-9-7 Fujiwara, Funabashi-shi, Chiba Sanwa Chemical Co., Ltd. (72) Inventor Mitsuyoshi Hoshino 4-18-15 Bunzo, Urawa-shi, Saitama (72) ) Inventor Ryoji Naoe 2-44-8 Kamiya, Ushiku-shi, Ibaraki F-term (reference) 4J004 AA05 AB01 CA03 CA04 CC02 EA01 FA01 FA08 GA01

Claims (3)

[Claims] 1. A buried position of a polyethylene gas pipe, characterized in that an adhesive layer is formed on one surface of a tape obtained by molding a mixture of waste polyethylene gas pipe and low-density polyethylene. Wiring fixing tape. 2. The wiring fixing tape according to claim 1, wherein the content of the low-density polyethylene in the mixture is 2 to 20% by weight. 3. A method in which a mixture of waste gas from a polyethylene gas pipe and low-density polyethylene is formed into a film by an inflation method, wherein the Elmendorf tear strength (TR _MD ) in the take-off direction of a film having a thickness of about 80 μm is determined. A method for producing a film for tape using waste gas pipe made of polyethylene, characterized in that the film is formed so as to have a tear strength (TR _TD ) of 5 to 30% perpendicular to the tape.