JPH06270339A - Self-adhesive tape or sheet and production thereof - Google Patents

Abstract

PURPOSE:To produce a self-adhesive tape or sheet constant and stable in the releasability with release paper by judging good release paper having no small destructed part in its silicone layer due to discharge generated by voltage lower than 10kv. CONSTITUTION:A silicone release layer with a thickness of 2mum is provided on both surfaces of fine paper and release paper wound in a roll form is delivered at a controlled delivery speed while discharge is performed on the surface of the silicone layer of the release paper so that charge voltage becomes 10kv. A fabric impregnated with a mixed soln. prepared by sufficiently mixing 2 pts.wt. of oil-based ink for a felt pen and 8 pts.wt. of isopropyl alcohol and applied to the surface of the silicone layer of the release paper so as to lightly wipe the silicone layer to search a discharge place. As a result, an inferior product wherein a large number of small zigzag crack parts formed from gathered extremely fine lines are detected is removed and only good release paper is used to obtain a self-adhesive tape according to a usual method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an adhesive tape or sheet using a release paper having a certain releasing property when applied to an adhesive surface such as an adhesive tape or sheet.

2. Description of the Related Art In the production of an adhesive tape or sheet, a pressure-sensitive adhesive layer is formed on a silicon release layer surface of a release paper having a silicon release layer, and a base sheet is attached to the release layer to form a base sheet. The method of transfer to is done. Silicon release paper used in the production of such adhesive tapes or sheets is
In that state or in a state in which, for example, a double-sided adhesive tape is laminated on one side thereof, the feeding and winding are performed.
In this case, the surface of the silicone release paper (the exposed surface of the silicon layer)
Static electricity is generated in the battery, and when the charged voltage becomes high, discharge occurs during feeding and winding.

This discharge destroys the silicon layer on the surface of the release paper, causing cracks. At this portion, the adhesive of the adhesive tape may stick to the paper which is the core material of the release paper, resulting in defective development of the adhesive tape or tearing of the adhesive tape or the release paper.

However, it is difficult to judge whether or not the silicon layer on the surface of the release paper is destroyed by just visually observing the silicon layer as it is. Therefore, as this inspection method, a method of applying color ink with a felt pen or the like to the surface of the silicon layer and detecting the presence or absence of the destroyed portion is performed.

Further, in Japanese Patent Laid-Open No. 4-110145,
Fine powder such as carbon black is sprinkled on the surface of the silicon layer of the silicon release paper, the fine powder penetrates into the finely broken portion of the silicon layer caused by the electric discharge, and the excess fine powder is removed. A method for detecting a broken portion is described.

[0005]

In the inspection method using the color ink described above, a large breakage portion of the silicon layer due to a spark generated at a high voltage of 20 kv or more can be detected, but a small breakage due to a discharge generated at a voltage lower than 10 kv. Since the solid portion of the color ink has a large solid content, the portion is hard to be repelled by the silicon surface, and since the amount of the solvent is small, drying immediately after coating is fast and a film is formed on the coated surface, which cannot be detected. In the method described in JP-A-4-110145, fine powder such as carbon black is handled,
This scatters and stains the surrounding area or floats in the air, which is a sanitary problem.

The present invention solves the above-mentioned conventional problems, and
An object of the present invention is to provide a method for producing an adhesive tape or sheet, which can detect a small broken portion of a silicon layer due to a discharge generated at a voltage lower than 0 kv and can use only a good release paper having no defect in the silicon layer. And

[0007]

According to the method of the present invention, the silicon layer surface of the release paper is coated with a mixture of an oil-based ink and an alcohol, and the ink is allowed to penetrate into a defective portion of the silicon layer to thereby destroy the silicon layer. Is detected, and a pressure-sensitive adhesive layer is formed on the surface of the release paper determined to be non-defective.

The oil-based ink used in the method of the present invention includes:
For example, those widely used in felt-tip pens can be cited.

Examples of alcohols include isopropyl alcohol, ethyl alcohol, methyl alcohol, and the like. However, isopropyl alcohol is preferable because it has high detection performance.

In the method of the present invention, a mixture of oil-based ink and alcohol is used. This is because the surface activity of the silicon layer is very low, and the fact that the wettability with a liquid causes it to repel, and the oil-based ink alone has a high solid content concentration and is difficult to repel on the silicon layer side. 10 kv
It is an improvement in that it is difficult for the ink to enter the minute cracks in the silicon layer that occur in the following, and because the amount of the solvent is small, it dries quickly and a film is formed on the entire coating surface, which cannot be detected.

In the present invention, by adding alcohol to the oil-based ink, the solid content concentration of the oil-based ink is reduced, the drying time of the solvent is lengthened, and the ink easily enters cracks on the surface of the silicon layer. By making it easier to repel, it is possible to detect small cracks that could not be detected until now.

The mixing ratio of the oil-based ink and alcohol is
The objective can be achieved in the range of 2: 8 to 4: 6. The weight ratio of the alcohol 8 to the oil-based ink 2 is preferable because it has the best detection performance.

To apply the above-mentioned mixed solution to the silicon layer surface, there are methods such as lightly wiping the silicon layer surface with a cloth soaked with the mixed solution, or applying the mixed solution to a brush and applying it to the silicon layer surface. If there is little excess ink on the surface of the silicon layer coated with the mixed solution, as in the case of wiping it with a cloth, leave it as it is and dry it, and the cracks detected by the ink will not interfere. I can observe. If there is a large amount of excess ink, such as when applying it with a brush, simply wipe off and observe.

In the present invention, a non-defective release paper having no defects such as cracks in the silicon layer is selected as described above, and the adhesive layer is formed on the silicon layer surface of the release paper. After that, the pressure-sensitive adhesive tape or sheet is manufactured according to a conventional method which has been conventionally used.

[0015]

In the method of the present invention, a mixed liquid prepared by adding alcohol to an oil-based ink is used to judge whether the release paper is good or not. Therefore, the mixed liquid on the surface of the silicon layer has poor wettability and is easily repelled. Also, since the solid content concentration of the ink is low, the drying time of the mixed liquid is long, which makes it easier for the ink components to penetrate into the cracked portions of the silicon layer surface, and it is determined whether the release paper is defective or good. Can be done easily. Then, the adhesive tape or sheet can be manufactured using only a good release paper.

[0016]

EXAMPLES Next, examples of the present invention will be described. (Example) A mixed solution was prepared by sufficiently mixing 2 parts by weight of an oil-based ink for a felt pen and 8 parts by weight of isopropyl alcohol. A 25 μm thick polyethylene resin is laminated on both sides of a high quality paper, and a 2 μm thick silicon layer is provided on the polyethylene resin surface. While feeding the roll-shaped release paper, the feeding speed is adjusted and the electrification voltage is 10 kv. Then, the release paper was fed while discharging the silicon layer surface.

The mixed solution was soaked in a cloth, which was applied to the silicon layer surface of the release paper and lightly wiped to find a discharge location. As a result, there was a defective product in which a large number of small lightning-like cracks formed by gathering extremely thin lines were detected. Excluding this defective product, only good release paper was selected.

An adhesive tape was obtained by applying a pressure-sensitive adhesive to the surface of the silicon layer using only the above-mentioned non-defective release paper and drying it, and then laminating a base film on the pressure-sensitive adhesive layer.

(Comparative Example 1) A discharge point was searched for in the same manner as in Example except that ethyl acetate was used instead of isopropyl alcohol, but only a small amount could be detected.

(Comparative Example 2) A discharge location was searched for in the same manner as in Example except that toluene was used instead of isopropyl alcohol, but only a small amount could be detected.

[0021]

EFFECTS OF THE INVENTION The method of the present invention is configured as described above. Since a mixed solution of alcohol added to oil-based ink is used to determine the quality of release paper, the solid content concentration of the oil-based ink is reduced and Ink becomes easy to enter the cracks on the surface of the silicon layer due to the long drying time. Further, the ink is easily repelled on the silicon layer surface, and as a result, visual cracks on the silicon layer surface are noticeable, and even small defects in the silicon layer due to discharge generated at a low voltage lower than 10 kv can be detected. Also, it is possible to inspect the vicinity without any problems in terms of hygiene. As described above, since the release tape is manufactured by using only a good release paper having no defects on the surface of the silicon layer, the obtained adhesive tape or sheet has a constant and stable release property with the release paper.

Claims (1)

[Claims] 1. A broken part of the silicon layer is detected by applying a mixed liquid of oil-based ink and alcohol to the surface of the silicon paper on the surface of the release paper and allowing the ink to enter the broken part of the silicon layer. A method for producing an adhesive tape or sheet, which comprises forming an adhesive layer on the surface of the release paper.