JPS61254330A - Surface-treatment of plastic film - Google Patents

Abstract

PURPOSE:To enable to smoothly obtain a treated roughened surface, the adherence of which to adhesive mass is favorable, by a method wherein the surface of running film is roughened at a surface-roughening device and, after that, the same surface is further discharge-treated with a corona discharge treating device. CONSTITUTION:The title surface-treating is formed by employing a surface roughening device 3 having rough-surface-forming rolls (screen rolls, emboss roll or the like) 4a and 4b and a corona discharge treating device 5 in tandem. With the devices an mentioned above, film F delivered from a delivery part 1 is mechanically deformed to a produce irregularities by pressing forces given by the rough-surface-forming rolls 4a and 4b when the film F passes through the surface roughening device 3 part. In addition, the film F is discharge-treated with corona discharge developed between a high-tension electrode 8 and a corona discharge treatment receiving metal roll 11 when the film F passes through the corona discharge treating device 5 part. Consequently, because oxygen-containing functional groups are further introduced in said irregular roughened surface part on the surface of the film, a roughened surface with satisfactory adherence is obtained.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a surface treatment method for obtaining a plastic film for adhesive tape that has a rough surface on one side and has good adhesion to an adhesive. .

<Conventional technology> Conventionally, in order to produce a film having a surface (rough surface, etc.) that has good adhesion to an adhesive, mesh processing or embossed cooling rolls (rough surface forming rolls) have been used. Alternatively, the surface roughening treatment was carried out using a surface roughening treatment device equipped with an abrasive brush, abrasive paper, etc. installed in the film manufacturing process or in a separate process. Furthermore, a corona discharge device installed in the same manner as this surface roughening treatment device was used.

<Problems to be Solved by the Invention> However, when using the meshing roll or embossing roll, it is difficult to obtain a desired rough surface.

In addition, in the case of using the above-mentioned surface roughening treatment device using abrasive brushes and abrasive paper, polishing residue is generated, which reduces the adhesion with the adhesive and causes clogging, and furthermore, these rough surfaces In many cases, sufficient effects cannot be obtained by chemical treatment alone.

When using a corona discharge device, an undercoat treatment is applied if necessary when applying the adhesive; however, corona discharge treatment alone does not provide sufficient treatment, and when combined with an undercoat treatment, , requiring the use of solvents, which not only increases costs but also poses safety and hygiene problems.

<Means for Solving the Problems> The present invention was made in view of such conventional drawbacks, and its characteristic point is that when producing a polyolefin film for adhesive tape, a rough surface forming roll ( A tandem combination of a corona discharge treatment device and a roughening device with a mesh processing roll, embossing roll, etc., or a polishing brush, abrasive paper, etc. with an abrasive residue removal device, can improve the film surface. The objective is to continuously roughen the surface of the adhesive, that is, to continuously improve its adhesion to the adhesive.

As described above, in the present invention, first, a roughening device having a roughening roll (mesh processing roll, embossing roll, etc.) or a polishing brush having an abrasive residue removing device, an abrasive paper, etc. Since the surface of the film is mechanically treated in a chemical treatment device and then subjected to corona discharge treatment, a roughened surface with good adhesion to adhesives can be obtained extremely smoothly.

<Example> FIG. 1 schematically shows an apparatus for carrying out the present invention.

In the figure, F is a film for roughening the surface (object to be processed), 1 is a feeding part of the film F, 2 is a winding part of the film F, 3 is a roughening roll (a mesh processing roll, (embossed roll, etc.) 4. A and 4b are roughening devices, 5 is a corona discharge treatment device, and 6 is a guide roll installed during film travel.

The corona discharge treatment apparatus 5 also includes a high voltage electrode 8 connected to a high voltage generator 7, and a corona discharge treatment optical metal roll 1 having an insulating layer 9 applied to the outer periphery and connected to a ground 10.
1, and its high voltage electrode 8 is opposed to the film running surface of the corona discharge treated optical metal roll 11 with a slight distance therebetween.

According to this device, when the film F sent out from the delivery section 1 passes through the surface roughening device 3 section, mechanical deformation is applied to the film F by the pressing force of the surface roughening rolls 4a and 4b. That is, in the case of a mesh processing roll, mesh marks are formed, and in the case of an embossing roll, embossing marks are formed as an uneven rough surface.

Although the roughness of this uneven surface is sometimes insufficient, in the present invention, when the film F further passes through the corona discharge treatment device 5 section, the high voltage electrode 8 and the corona discharge treatment are performed. Due to corona discharge between the receiving metal rolls 11,
Discharge treated. By this discharge treatment, oxygen-containing functional groups (C=0, -C
OOH, etc.) will be introduced.

In other words, a rough surface with sufficient adhesion can be obtained.

Therefore, the corona discharge treatment eliminates the need for an undercoating treatment step that was conventionally required.

Incidentally, a prototype product according to the present invention was manufactured using a polyethylene film under the conditions shown in Table 1.

Table 1 The prototype films in Table 1 were tested using the T-PEEL TEST.
rd Te5t Method for
PEEL RESISTANCE OF
ADHES I VES) test method (ASTD 1)
876-72), the adhesion force between the film and the adhesive (Kg
/cm), it was found that in this prototype, cohesive failure occurred in the adhesive part instead of interfacial failure in the film and adhesive part, indicating that there was sufficient adhesion.

<Effects of the Invention> As is clear from the above description, according to the present invention, a polishing brush having a roughening device having a roughening roll (meshing roll, embossing roll, etc.) or a polishing residue removing device This method uses a surface roughening device with abrasive paper and a corona discharge treatment device in tandem, thereby providing an excellent surface treatment method for plastic films that has good adhesion and can be obtained extremely smoothly. be able to.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing an apparatus for carrying out the method for surface treatment of plastic films according to the present invention. In the figure, F... Film, 3... Roughening device, 4a, 4b... Roughening roll, 5... Corona discharge treatment device, 8... High voltage electrode, 11... Corona Electric discharge treatment receiving metal roll.

Claims (1)

[Claims] A method for surface treatment of a plastic film, which comprises roughening the surface of a running film using a conventional surface roughening device, and then subjecting the same surface to a discharge treatment using a corona discharge treatment device.