JPH09157603A - Coating tape for metal plate-jointing part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tape for coating the jointing part between the metal plates, having high heat resistance and causing no problem of coating repellency. SOLUTION: This tape for coating the jointing part of metal plates is prepared by forming, on one surface of a heat-resistant film, an acrylic heat- resistant adhesive layer of >=60% gel fraction and <=3mm of the holding power in a 200 deg.C atmosphere (the shift distance under following conditions: the substrate: an aluminum plate; the adhesion area: 10mm×20mm, and the uniform load: 200g).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape for coating a metal plate joint portion composed of a heat-resistant film and an acrylic pressure-sensitive adhesive having good heat resistance.

[0002]

2. Description of the Related Art When passing a metal plate through a coating process, when moving from one metal roll to the next metal roll in the coating process,
It is necessary to join metal sheets together. In this joining, it is common to make an appropriate cut at the end of the raw material and mechanically entangle it. However, when making the above break,
A metal powder, which is a chip, is formed around the cut edge, and when it adheres to a roll or the like in the transportation process or the like, it becomes a foreign substance on the surface of the metal plate, which is a serious defect of poor appearance particularly in the coating process.

For this reason, conventionally, measures have been taken to prevent the metal powder from adhering to a roll by covering both sides of the metal plate joint with adhesive tape. Known coating tapes used for this purpose include a paper base material provided with a rubber-based adhesive and a fluorine base material provided with a silicon-based adhesive.

[0004]

However, the coating tape having a rubber-based pressure-sensitive adhesive on the paper substrate is inferior in heat resistance,
It cannot be used because the temperature of the line temperature increases due to the temperature increase. Also, with a coating tape that has a silicon-based adhesive on a fluorine-based base material, there is no problem in terms of heat resistance, but the silicon-based adhesive adheres to the rolls, etc. However, when transferred, there is a problem that paint cissing occurs.

In view of the above circumstances, the present invention is a tape for coating a joint portion of metal plates, which has good heat resistance and does not cause problems such as cissing in a coating process of the metal plate. The purpose is to provide a tape.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above object, and as a result, found that an adhesive tape having an acrylic adhesive having a specific constitution provided on one surface of a heat-resistant film was found to be used. As a tape for coating metal plate joints, it has excellent heat resistance, and does not cause problems such as cratering in the coating process of metal plates, and it has significantly better performance than conventional coating tapes. They found that they could exert their effects, and completed the present invention.

That is, according to the present invention, the gel fraction on one surface of the heat resistant film is 60% or more, and the holding power in an atmosphere at 200 ° C. (adherent: aluminum plate, adhesive area: 10 mm × 20)
mm, uniform load: shift distance at 200 g) is within 3 mm, and relates to a tape for coating a metal plate joint portion provided with an acrylic pressure-sensitive adhesive having good heat resistance.

In this specification, the gel fraction of the pressure-sensitive adhesive means the pressure-sensitive adhesive after being immersed in toluene at room temperature for 48 hours.
The insoluble matter weight (G ₁ ) was measured, and this and the initial weight (G ₀ )
Therefore, the value is obtained as [G ₁ / G ₀ ] × 100 (%).

Further, the holding power in an atmosphere of 200 ° C. (adherent: aluminum plate, adhesive area: 10 mm × 20 mm, uniform load: shift distance at 200 g) means 10 mm × 20 mm of adhesive tape on an aluminum plate. After sticking with the adhesive area of, the aluminum plate is hung down, a uniform load of 200 g is applied to the lower free end of the adhesive tape, and the adhesive tape at 200 ° C
This is a measurement of the shift distance (mm) after 60 minutes of pulling.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The heat resistant film used as a substrate in the present invention is usually a polymer film having a heat resistant temperature of 150 ° C. or higher (continuous usable temperature), for example, a polyimide film (Kapton film). And polytetrafluoroethylene film (PTF
E film), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer film (PFA film), ethylene-tetrafluoroethylene copolymer film (ETFE film), and other fluorine resin-based films. it can. The thickness of these heat resistant films is not particularly limited, but generally 2
It is preferably about 5 to 100 μm.

The acrylic pressure-sensitive adhesive used in the present invention has a gel fraction of 60% or more, preferably 80% or more (usually up to 95%) and a holding power of 3 at 200 ° C.
within mm, preferably within 1 mm, particularly preferably 0.5
Within mm. Even if such an acrylic pressure-sensitive adhesive adheres to a roll or the like and is transferred to the metal surface, it will cause problems such as cissing in the coating process of the metal plate like the conventional silicon-based pressure-sensitive adhesive. In addition, since it has high heat resistance, it has an advantage that it can be used as a coating tape without trouble even if it is subjected to a high temperature process.

Such an acrylic pressure-sensitive adhesive is, for example, a main monomer containing (meth) acrylic acid alkyl ester as an essential component in an amount of 75 to 92% by weight and a homopolymer having a glass transition temperature of 50 ° C. or higher. -
An internal cross-linking agent is added to the monomer mixture of 25 to 8% by weight, and an appropriate photopolymerization initiator such as 1-hydroxycyclohexyl phenyl ketone, benzyl dimethyl ketal, and benzophenone is usually added to the mixture, and ultraviolet rays and It can be prepared by a method such as bulk polymerization with an electron beam.

Examples of the (meth) acrylic acid alkyl ester include isooctyl (meth) acrylic acid, 2-ethylhexyl (meth) acrylic acid, isononyl (meth) acrylic acid, and isodecyl (meth) acrylic acid. Main monomers include vinyl acetate, styrene, in addition to these (meth) acrylic acid alkyl esters.
Other vinyl type monomers such as acrylonitrile may be used in combination.

As the carboxyl group-containing monomer,
Examples thereof include (meth) acrylic acid, (anhydrous) maleic acid, itaconic acid, fumaric acid and crotonic acid. As the internal cross-linking agent, ethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate
To tetramethylol methane tetra (meth) acrylate
And polyfunctional monomers such as trimethyl and trimethylolpropane tri (meth) acrylate are used. This polyfunctional monomer is usually used in an amount of 0.1 to 3.0 per 100 parts by weight of a monomer mixture of a main monomer containing a (meth) acrylic acid alkyl ester as an essential component and a carboxyl group-containing monomer.
Used in parts by weight.

Such an acrylic pressure-sensitive adhesive may contain various additives such as tackifiers, fillers, pigments, antioxidants and antioxidants, if necessary.
These additives may be used in a usual amount as long as the gel fraction of the pressure-sensitive adhesive and the holding power in a 200 ° C. atmosphere are kept within the above ranges.

In the present invention, in order to provide the above-mentioned acrylic pressure-sensitive adhesive on one surface of the heat-resistant film, the polymerizable composition before being irradiated with ultraviolet rays or electron beams has a thickness of 3 after polymerization and curing.
It may be coated on the heat-resistant film so as to have a thickness of 0 to 100 μm, and then irradiated with ultraviolet rays or electron beams by an appropriate means to polymerize and cure. As a result, the coating tape having good heat resistance, which is the object of the present invention, can be produced.

[0017]

Next, an embodiment of the present invention will be described in more detail. In the following, “parts” means “parts by weight”.

Example 1 100 parts of a monomer mixture consisting of 90 parts of isooctyl acrylate and 10 parts of acrylic acid was used as a photopolymerization initiator as Irgakiure-184 (manufactured by Ciba-Geigy).
Was thoroughly substituted with nitrogen and irradiated with ultraviolet rays of about 100 mj / cm ² with a high pressure mercury lamp.

With respect to the viscous material thus obtained, 0.2 part of trimethylolpropane triacrylate as an internal cross-linking agent and 2,4-bis-
(N-octylthio) -6- (4-hydroxy-3,5
-Di-t-butylanilino) -1,3,5-triazine (2 parts) was added, and the polymerizable composition was adhesively treated with sodium to give a fluorine resin film (PTFE film) having a thickness of 0.05 mm. Was coated on the above so as to have a thickness of 50 μm.

Next, in order to eliminate polymerization inhibition by oxygen, the surface of the polymerizable composition coated on the fluorine resin film is covered with a release liner made of polyethylene terephthalate film, and high pressure mercury is applied. A coating tape was prepared by irradiating with ultraviolet rays of about 1,400 mj / cm ^{2 with} a lamp.

Comparative Example 1 90 parts of isooctyl acrylate, 10 parts of acrylic acid, 0.5 part of benzoyl peroxide and 400 parts of toluene.
After performing nitrogen gas replacement on the mixture of parts,
Solution polymerization was carried out at 60 ° C. for 8 hours to obtain an acrylic copolymer. An adhesive solution was prepared by adding 5 parts of benzoylperoxide to 100 parts of this acrylic copolymer (solid content).

This adhesive solution was treated with sodium to obtain a fluorine resin film (PTF) with a thickness of 0.05 mm.
E film) was coated so that the thickness after drying would be 50 μm, and heated at 150 ° C. for 5 minutes to prepare a coating tape.

The coating tapes of Example 1 and Comparative Example 1 were subjected to an adhesive strength test and a peeling test in the following manner. The test results are shown in Table 1 below together with the gel fraction of each pressure-sensitive adhesive and the holding power in the atmosphere of 200 ° C.

<Adhesiveness test> A coating tape is pressure-bonded to an aluminum plate by a method of reciprocating a 2 Kg roller once,
After leaving for a minute, the peeling speed is 3 in an atmosphere of 23 ° C and 65% RH.
180 degree peeling force when peeled off at 00 mm / min (g /
20 mm width).

<Peeling Test> A coating tape was attached to an aluminum plate having a thickness of 0.1 mm with a hand roller so that the adhesion area was 50 mm × 50 mm, and this was placed in a dryer at 200 ° C. for 3 days. When the tape was left for a minute, peeling of the tape was observed.

[0026]

In addition to the advantage that the coating tape of Example 1 of the present invention is essentially free from problems such as paint cissing,
From the results in Table 1, it can be seen that the adhesiveness is excellent, the heat resistance is good, and the peel test in a high temperature atmosphere is sufficiently endured.

[0028]

As described above, according to the present invention, an acrylic adhesive having a specific constitution is provided on one surface of a heat-resistant film, so that the heat resistance is good, and moreover, in the step of coating a metal plate. It is possible to provide a tape for coating a metal plate joint which does not essentially cause problems such as paint cissing.

Claims (1)

[Claims] 1. A gel fraction of 60 on one surface of a heat resistant film.
% Or more, holding power in an atmosphere of 200 ° C. (adherent: aluminum plate, adhesive area: 10 mm × 20 mm, uniform load: 20
A tape for coating metal plate joints provided with an acrylic pressure-sensitive adhesive having good heat resistance with a displacement distance of 0 g) of 3 mm or less.