JPS60215184A - Mark for buried material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a buried object marker that is buried near an underground object to indicate the presence of the buried object when the ground is excavated.

[Prior art]

When repairing underground objects such as gas pipes, water and sewage pipes, power lines, communication lines, etc., or when burying other underground objects such as pipes nearby, it is necessary to excavate the ground. In order to prevent buried objects from being damaged by power shovels, etc., signs are printed above the buried objects, including the type of buried object, standards, burial period, warnings, etc. As a conventional buried object marker of this type, there is one in which a synthetic resin film is folded in at intervals in the longitudinal direction and spot welded at the overlapping portions.

However, because conventional buried object markers are made of low-density polyethylene film or polyvinyl chloride film, their strength is low, and if they come into contact with a power shovel after being buried in hard soil for a long time, ,
The drawback was that the film often broke and was not detected by workers on the ground.

[Purpose of the invention]

This invention is intended to improve the above-mentioned conventional drawbacks, and is made of a woven fabric made of a stretched tape of a high-density polyethylene film having specific physical properties, and a woven fabric made of a stretched tape of a low-density polyethylene film having specific physical properties. By using a laminate sheet that is bonded to the display film through an intermediate adhesive layer made of low-density polyethylene having specific physical properties, it has high strength and excellent folding and melting properties.

To provide a buried object sign capable of surely indicating the location of a buried object by appropriately extending a folded part without being damaged during excavation.

[Structure of the invention]

This invention has a density of 0.940 g/cIi? As described above, a woven fabric made of a stretched tape made by stretching a high-density polyethylene film with a melt flow index of 0.1 to 3 g, 710 m1n at a magnification of 5 to 10 times, and a woven fabric with a density of 0.930 g/L? n?
Melt flow index below 0.5-8 g/10
A display film made of a low-density polyethylene film of m1n is laminated with an intermediate adhesive layer made of low-density polyethylene having a density of 0.924g10f or less and a melt flow index of 3 to 12g/10m1n, and this The laminate sheet is a buried object marker characterized by having overlapping parts folded in at intervals in the longitudinal direction, and having partial welded parts in the overlapping parts.

The present invention will be explained below with reference to the drawings. The drawings show examples, and FIG. 1 is a sectional view of a laminate sheet, and FIG. 2 is a perspective view of a sign.

The laminate sheet 1 used in the present invention has a structure in which a woven fabric 2 and a display film 3 are bonded together with an intermediate adhesive layer 4 interposed therebetween. Woven fabric 2 has a density of 0.940g
/c1v or more, preferably 0.951 to 0.954g/
cn? , melt flow index (hereinafter referred to as MF■) 0.1-3g710mln, preferably 0.65-0
．． This cloth is made by weaving a stretched tape 5 obtained by slitting a 9g/10m1n high-density polyethylene film and heating and stretching it to a ratio of 5 to 10 times using a normal loom such as an ordinary loom or an innovative loom.

The stretched tape 5 has a strength of about 5 g/denier,
The strength per unit area is approximately 4,000 kg/c+#, which is approximately 300 kg/al of the raw resin, and the strength of the woven fabric 2 is greater than that of the raw resin film. Since it has good chemical resistance, it has great durability underground and has excellent fusion properties with the intermediate fusion layer 4. The reason why the density and MFI of the raw resin are limited is that the density is 0.940g/c11? If the MFI is less than 0.1 g/10 m1n, the extrusion rate will decrease, and if the MFI exceeds 3 g/710 m1n, bubbles will be unstable during fabric forming by the inflation method and will easily break during weaving. .

The stretched tape 5 is formed by slitting a film made of the above-mentioned high-density polyethylene into a predetermined width using a razor blade, a rotary blade, etc., and heating and stretching the film at a temperature below the melting point of the raw material resin and above the secondary dislocation point. Ru. Stretching is carried out by a difference in peripheral speed between nip rolls on the inlet side and outlet side of the heating device, and the stretching ratio is 4, generally 5 to 10 times, but preferably 6 to 8 times.

If the stretching ratio is too low, strength cannot be obtained, and if it is too high, the yarn tends to split into fibers, resulting in poor weavability.

The method of weaving the stretched tape 5 is not particularly limited.

Display film 3 has a density of 0.930g/cn? Below, preferably 0.921-0.922g/cn? , MFIo,
5-8 g/10mln.

Preferably, it is made of a low-density polyethylene film of 2.7 to 3.3 g/10 m1n, and on the back side (intermediate adhesive layer 4 side), the type of buried object, the standard, the burial period, and warnings are printed with letters, pictures, etc. A portion 6 is formed. The reason why the density and MFI of the raw resin are limited is that the density is 0,931
)g/cn? If it exceeds, the foldability of the laminate sheet 1 will deteriorate, and if the M
This is because if it exceeds m1n, the printed display portion 6 is likely to be disturbed due to tension during lamination.

The woven fabric 2 and the display film 3 are bonded together via an intermediate adhesive layer 4, and are formed of a laminate sheet of 1 m1n, preferably low density polyethylene of 3.3 to 3.8 g/10 m1n. The reason why the density and MFI of the raw material resin are limited is that if the density exceeds 0.924 g/1ffl, the folding properties will be poor, and if the MFI is less than 3 g/10 m1n, the melting temperature will have to be increased. The orientation of the cloth 2 is relaxed, leading to a decrease in strength, and M
This is because when FI exceeds 12 g/10 m1n, uneven thickness tends to occur.

The woven fabric 2 and the display film 3 are preferably bonded together by extrusion lamination, but dry lamination or other methods may also be used. In this case, the intermediate fusion layer 4 is formed through the display section 6.

It is desirable that the display section 6 be formed of a material with good fusibility. When the display section 6 is formed on the surface (outside) of the display film 3, the material thereof is selected in consideration of its fusion properties with the display film 3 and its durability underground.

In the sign 7 of the present invention, the laminate film 1 formed as described above is folded at intervals in the longitudinal direction to form folded portions 8, as shown in FIG. Welding part 1 by spot welding etc. to the overlapping part 9
0 is formed.

The folding magnification, that is, the magnification at which the laminate sheet 1 stretches when the welded portion 10 is broken, is usually 2 to 2.

Although it is 4 times, it can be arbitrarily determined depending on the location, soil quality, etc. In FIG. 2, the folding method is such that the tip of the folding part 8 overlaps with the adjacent folding part 8, but depending on the folding magnification, a folding method that does not overlap is also possible. Further, the overlapping portion 9 is usually made of three or five layers, but is not limited thereto.

The welded portion 10 is not limited to a spot shape, but may be formed by partially welding the overlapping portion 9, such as a broken line shape. In FIG. 2, the ends on both sides of the folded part 8 overlap, so a welded part 1O is formed at that end. However, if the ends on both sides do not overlap, any part of the overlapped part 9 can be formed. The welded portion 10 can be formed in the welded portion 10 . It is desirable that the overlapping portion 10 be formed to withstand the tension during burying and to be easily destroyed during excavation.

The sign 7 configured as described above becomes a sign embedded near an underground object such as a gas pipe (usually above the object) to indicate the location of the object. When the buried object is caught by a power shovel or the like during excavation, the welded portion 10 is destroyed and the laminate sheet 1 is expanded to indicate the location of the buried object.

At this time, since the strength of the laminate sheet 1 is high, even if the buried soil hardens, the laminate sheet 1 will be pulled out without being cut midway, and part or all of the folded part 8 will be released, and the sign 7 will be stretched, ensuring that the The location of buried objects can be displayed. In addition, the woven fabric 2, the display film 3, and the intermediate adhesion layer 4, which are the materials of the laminate sheet 1, all have high durability underground, and because they are buried in a composite state, there is little loss of strength. , can be used for a long time. Further, when the display section 6 is provided on the back surface of the display film 3, the durability under the ground is increased, and accurate display can be performed for a long time.

In the above description, the woven fabric 2 of the laminate sheet 1
There is no problem in providing another film or the like between the display film 3 and the intermediate adhesive layer 4 or on the outer surface thereof, or forming the display section 6 at a position other than the back surface. Furthermore, the folding method, polymerization method, etc. of the label 7 are not limited to those shown in the drawings.

[Embodiments of the invention]

Example density 0.953g/cJ, MF I 0.80g/1
A film with a thickness of 47 μm was formed using 0 m1n of high-density polyethylene, and this was slit and stretched at a stretching temperature of 110 μm.
Stretched to 1500 denier and strength 5.0 at ℃
A stretched tape of g/denier was produced and woven on a loom to a length of 14 lengths and a width of 12 lengths/1 inch to obtain a woven fabric 2 shown in FIG. The strength of this woven fabric 2 is 165 kg/5 c+e
, width 155kg/5c+a.

On the other hand, density 0.921'g/cd, M F I 3.
A display part 6 is formed by printing on the back side of the display film 3 which is made of a 40μ thick film made of low density polyethylene of 0g/10m1n, and this and the above woven fabric 2 are combined to form a display part 6 with a density of 0.
．． 923g/c11? , MFI 3.5g/10
Extrusion lamination was performed and bonded through low-density polyethylene of m1n to form a laminate sheet 1 having an intermediate adhesive layer 4 having a thickness of 30 μm.

The obtained laminate sheet 1 was slit to a width of 150 mm, folded 3.5 times as much as shown in FIG. 2, and welded portions 10 were formed in two locations at each overlapped portion 9 by spot welding to obtain a marker 7. The peel strength in the longitudinal direction of the sheet of the welded part 10 of the obtained sign 7 was 5.5 kg (pulling speed 20 cm).
/min, the same applies hereinafter), the longitudinal strength of laminate sheet 1 is 168 kg/50m width (pulling speed 20cm/
min, hereinafter the same).

When this sign 7 was buried at a depth of 5.0 cm underground and later excavated with a power shovel, the welded part 10 of the sign 7 peeled off, and the overlapping part 9 stretched and did not need to be cut, so that it could be used as a buried object sign. was confirmed.

Comparative Example 1 Only display film 3 in Example (however, 200 μ thick)
The peel strength in the longitudinal direction of the welded part of the sheet folded in the same manner as in the example was 2.9 kg, and the strength of the display film 3 was 14 kg/50 m width.

The sign was buried 50cm underground, and when it was dug up with a power shovel later, the sign was cut off.

Comparative Example 2 Density 0.934 g/cJ, M F I 0.80 g/10 instead of polyethylene for the woven fabric in Example
When the same procedure was performed except that polyethylene of m1n was used, the peel strength in the longitudinal direction of the sheet at the welded part of the sign was 2.5.
The strength of the laminate sheet was 90 kg and the width was 15 cm.

When this sign was buried 50cm underground and later dug up using a power shovel, it was found that more than half of the sign had been cut in the width direction.

〔Effect of the invention〕

According to the present invention, a woven fabric made of a stretched tape of a film made of high-density polyethylene having specific physical properties and a display film made of a film made of low-density polyethylene having specific physical properties are combined with a woven fabric made of a stretched tape of a film made of low-density polyethylene The laminate sheets are bonded together via an intermediate adhesive layer, which is then folded, and the overlapping parts are welded together, resulting in great strength.

It has excellent folding and welding properties, and the folded part stretches out without being damaged during excavation, making it possible to reliably indicate the location of buried objects.It also has high durability underground and remains accurate for long periods of time. can be displayed.

[Brief explanation of the drawing]

1 and 2 show examples, with FIG. 1 being a sectional view of a laminate sheet, and FIG. 2 being a perspective view of a sign. DESCRIPTION OF SYMBOLS 1... Laminate sheet, 2... Woven fabric, 3... Display film, 4... Intermediate fusion layer, 5... Stretched tape,
6...display section, 7...signpost, 8...folding section, 9.
・Polymerized part, 10...welded part. Agent Patent Attorney Sei Yanagihara

Claims (5)

[Claims] (1) A woven fabric made of a stretched tape made by stretching a high-density polyethylene film with a density of 0.940 g/cJ or more and a melt flow index of 0.1 to 3 g/10 m1n at a magnification of 5 to 10 times, and a woven fabric with a density of 0.930 g/cn. ? In the following, a display film made of a low-density polyethylene film with a melt flow index of 0.5 to 8 g/10 m1n is
Density 0.924g/cn? The following Null 1-sheets are laminated together through an intermediate adhesive layer made of low-density polyethylene with a flow index of 3 to 12 g/]0 m1n, and this laminate sheet is folded at intervals in the longitudinal direction. A buried object marker having an overlapping part and a partially welded part in the overlapping part. (2) The buried object marker according to claim 1, wherein the stretched tape is obtained by slitting a film and then stretching it. (3) The buried object marker according to claim 1 or 2, wherein the display film has a display portion printed on the intermediate adhesive layer side. (4) The buried object marker according to any one of claims 1 to 3, wherein the intermediate adhesive layer is formed by extrusion lamination. (5) The buried object marker according to any one of claims 1 to 4, wherein the welded portion is formed by spot welding.