JPS6129705Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to improvements in colored adhesive tapes for display purposes.
The purpose of this invention is to provide a colored adhesive tape for display that is durable and does not discolor when wrapped around or attached to an adherend.

Colored adhesive tape for display is used for water pipes, transportation gas pipes,
It is used to protect underground cable protection pipes and to identify them. Water pipes are colored blue, sewer pipes are brown, and gas transport pipes are green. This is a method taken to prevent confusion in identifying pipes due to congestion in cities and congested pipeline networks that transport various fluids. is stipulated by government ordinance, etc. Therefore, it is essential that the colored adhesive tape for display remains unchanged for a long period of time when it is attached or wrapped around these transport pipes.
However, the tapes currently in use have the disadvantage of discoloration after being applied or wrapped around an adherend. These discolorations, such as blue turning to green, can lead to misidentification of the tube, which can lead to serious accidents. When we investigate what causes this discoloration, we find that the main base material of conventionally used display adhesive tapes is colored soft polyvinyl chloride, which is then made into sheets or tapes made of flexible polyvinyl chloride with a plasticizer. One side of this is coated with an adhesive. Transport pipes for various fluids include general carbon steel pipes, galvanized/iron pipes,
Or, for the purpose of burying a PVC pipe made from PVC, its outer surface is coated with anti-corrosion, anti-corrosion coal tar, coal tar epoxy resin, asphalt or pitch bituminous material, or a tape impregnated with these materials is wrapped. It is something that This bituminous material contains volatile yellow-brown low molecular weight substances. In the conventional tape, since the adhesive layer and the bituminous material on the surface of the pipe come into contact, the yellow-brown low-molecular substance penetrates through the adhesive layer into the polyvinyl chloride layer containing the plasticizer and mixes with the colorant. The discoloration caused by this causes confusion in identification. Also, those using polyethylene or polypropylene films as base materials instead of polyvinyl chloride have the same drawbacks even though no plasticizer is mixed therein. For example, a polyethylene film colored blue by phthalocyanine blue changes to green by coal tar enamel applied to a steel pipe.

The purpose of this project is to prevent discoloration that causes misidentification and confusion of these display colors, and a blocking layer is provided between the flexible base layer and the adhesive layer, and it is effective to use stretched polyester as the material for this layer. I found it. A stretched polyester film having a thickness of 0.006 to 0.009 mm can sufficiently function as an intermediate layer to block penetration of the dye. A composite film made by bonding such a thin polyester film to a flexible polyvinyl chloride film with an adhesive maintains its flexibility and conformability, and has the ability to be used as a wrapping material for covering and wrapping materials such as polyvinyl chloride and polyethylene. The present invention uses a thermosetting polyurethane adhesive as the adhesive, which is comparable to that of a film alone. Therefore, the colored adhesive tape for display according to the present invention is made by coating the colored composite film with an adhesive on the surface of the blocking layer of the polyester film.

To explain this idea with the help of drawings, Figure 1 shows the tape of the invention being wound around a core.
FIG. 2 shows a structure in which an adhesive layer 3 is applied to a composite film of a plasticized polyvinyl chloride film 1 and a polyester film 2 by enlarging a cut part of the tape of the present invention. Next, we will show the results of discoloration tests of the proposed tape with a polyester film as a barrier layer and a conventional display adhesive tape without this barrier layer.

A Original tape colored base material - blue polyvinyl chloride (plasticizer
(mixed with 45 parts of DOP) Film thickness: 0.16 mm Barrier layer - polyester film (product name: Toray Lumirror) Thickness: 0.009 mm Coat the above films together with thermosetting polyurethane adhesive so that the adhesion ^amount is 4 g/m2. I attached it and pasted it together.

Thickness of natural rubber adhesive layer: 0.030 mm (100 parts of pale crepe, 80 parts of YS resin, 1 part of anti-aging agent) B Commercially available tape coloring base - blue polyvinyl chloride (plasticizer same as above) Film thickness 0.18mm Natural rubber adhesive (same as above) layer thickness
0.030mm C Commercially available tape colored base material - blue polyethylene film (specific gravity
0.927) thickness 0.18mm Natural rubber adhesive (same as above) layer thickness
0.030 mm The colored base material of A above and the barrier layer pasted together were cut into 25 mm widths and stored in a constant temperature and humidity device at normal temperature of 65 ± 2 ° C and relative humidity of 80 ± 5% for 7 days. After returning to room temperature, a T-peel test was conducted in accordance with JIS K6854 (peel adhesion test method for adhesives). As a result, in both the normal product and the heated and humidified product, breakage of the polyester film serving as the barrier layer was observed, but no film delamination phenomenon occurred.

The above three types of tape (50 mm width) were wrapped around a steel pipe coated with coal tar and placed in an oven at 70°C to observe the degree of discoloration, and the following results were obtained.

Sample A shows no discoloration after 30 days.

Furthermore, when the same sample was peeled off from the steel pipe, there was no film delamination phenomenon between the colored base material and the blocking layer.

Sample B turns green after 1.5 hours.

Sample C turns green after 8 hours.

As described above, the colored adhesive tape for display according to the present invention is novel and useful for preventing discoloration.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the appearance of a colored adhesive tape for display according to the present invention, and FIG. 2 is an enlarged perspective view showing the structure of a cut part of the tape according to the present invention. 1... Polyvinyl chloride film, 2... Polyester film, 3... Adhesive layer.

Claims (1)

[Scope of utility model registration request] A colored pressure-sensitive adhesive tape for display, comprising a composite film formed by adhering a colored flexible base material of polyvinyl chloride film and a polyester film with an adhesive, and a pressure-sensitive adhesive applied to the surface of the polyester film.