JPH01308475A - Ultraviolet-curable hot pressure-sensitive adhesive film or sheet - Google Patents

Abstract

PURPOSE:To make it possible to transfer a uniform bubble-free film which does not exhibit any adhesiveness when being laminated, by forming an ultraviolet-curable hot pressure-sensitive adhesive layer on the surface of a plastic film or sheet. CONSTITUTION:An ultraviolet-curable hot pressure-sensitive adhesive is obtained by mixing 100pts.wt. total of 30-80pts.wt. hot pressure-sensitive adhesive comprising an acrylic resin of an m.p. of 70-100 deg.C and a tackifier (e.g., terpene resin) and 70-20pts.wt. ultraviolet-curable curing agent comprising polyacrylic monomer and oligomer is optionally mixed with 1-5pts.wt. additive (e.g., nitrocellulose). Said adhesive is applied to the surface of a plastic film or sheet 1 to form an adhesive layer 2 of a thickness of 5-100mum, and the resulting film or sheet is wound up into a roll. The adhesive layer 2 is applied to a coating surface 3 and the film or sheet is pressed against this surface with a heating roll 4 from the side of the film 1 to bond it to the surface 3. The film or sheet thus treated is irradiated with ultraviolet rays from the side of the film 1 to cure the adhesive layer 2, and the film 1 is peeled from the cured adhesive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a pressure-sensitive adhesive film or sheet that can be cured by ultraviolet light at high temperatures (70 to 100°C).

(Prior Art) Conventionally, a coating film is often formed by applying an ultraviolet curable paint to the surface of a metal plate, plastic plate or sheet, or paper product and curing it by irradiation with ultraviolet rays.

Although UV-cured coatings have a strong surface and are resistant to scratches, they have the disadvantage that they are difficult to cure due to the action of oxygen in the air, are prone to uneven coating due to poor leveling, and are susceptible to dust. . As a means to solve these drawbacks, the present inventor first invented a pressure-sensitive adhesive film in which a UV-curable pressure-sensitive adhesive layer was provided on the surface of a plastic film or sheet (hereinafter simply referred to as a film), and the metal plate 1 The surface to be painted, such as paper or plastic board, is covered with this pressure-sensitive adhesive film, the adhesive layer is cured by irradiation with ultraviolet rays, and then the film is removed to create an extremely beautiful mirror-like surface on the surface to be painted. He invented the formation of ultraviolet-curable coatings (see Japanese Patent Application No. 217904/1983).

This ultraviolet curable pressure-sensitive adhesive layer film can be applied to the surfaces of metal plates, plastic plates, paper, etc.
It is a very effective means for matte finishing and embossing, and it especially eliminates the effects of dust and the poisonous effect of oxygen from the air, which were problems when applying ultraviolet curable paints to the surface of these coatings. It was very effective in preventing

However, when applying this ultraviolet-curable pressure-sensitive adhesive to a film, the film remains sticky even after the solvent dries, so the film used had to be subjected to a release treatment using silicone resin or the like in advance. The above-mentioned adhesive is applied to the release-treated film using a roll-coater, etc. When the film is rolled up, there is no slippage between the films, making it difficult to wind them evenly. Machinery and skill were required.

Furthermore, when using the wound pressure-sensitive film, the surface to be coated is covered with the pressure-sensitive film,
At that time, it is necessary to remove air bubbles contained in the adhesive layer using a rubber roller or the like, and since the adhesive layer has adhesive properties, there is also the problem that dust tends to adhere thereto.

(Problems to be Solved by the Invention) As a result of various studies to solve these drawbacks, the present inventors found that the surface of a plastic film or sheet does not exhibit pressure-sensitive adhesion at room temperature, and does not exhibit pressure-sensitive adhesive properties at high temperatures (70°C to 100°C). discovered that a beautiful coating film could be created by providing a UV-curable heat-sensitive pressure-sensitive adhesive layer made of an UV-curable adhesive that exhibits pressure-sensitive adhesive properties and transferring this to the surface to be painted, and completed the present invention. One object of the present invention is to provide an ultraviolet curable heat-sensitive pressure adhesive film or sheet that is cured by ultraviolet rays and provides a beautiful and tough coating film.

(Means for Solving the Problems) That is, the present invention provides an ultraviolet curable heat-sensitive pressure-sensitive adhesive comprising an ultraviolet curable adhesive that exhibits pressure-sensitive adhesive properties at high temperatures (70°C to 100°C) on the surface of a plastic film or sheet. The adhesive layer is a plastic film or sheet.

Furthermore, the present invention will be explained in detail.

The ultraviolet curable heat-sensitive adhesive used in the present invention is:

By adding an ultraviolet curing agent composition to a heat-sensitive pressure adhesive made by mixing an acrylic resin with a melting point in the temperature range of 70°C to 100°C with a sticky preservative (also known as tackifier) and uniformly dissolving the mixture. can get.

Types of the tackifier to be added include natural rosin and its derivatives, terpene resins, styrene resin derivatives, etc., with terpene resins and styrene resin derivatives being particularly preferred.

The ultraviolet curing agent composition is a composition of a polyfunctional acrylic monomer and an oligomer.

The ratio of adding the ultraviolet curable composition to the heat-sensitive pressure adhesive is heat-sensitive pressure adhesive: 30 parts of the ultraviolet curable composition.
parts to 80 parts: 20 parts; if the heat-sensitive pressure adhesive is less than 30 parts, its function as a pressure-sensitive adhesive will be weakened and transfer by heat will be difficult; if the amount of the ultraviolet curable mixture is less than 20 parts, it will Curing is poor, and the toughness, solvent resistance, and beauty of the coating film are reduced.

The ultraviolet curable heat-sensitive pressure sensitive adhesive may further contain other additives. In particular, blocking at room temperature can be prevented by using a small amount of nitrified cotton with trocellulose, ethyl cellulose, hydroxypropyl cellulose, or cellulose acetate-butyrate as an additive, and without adding these celluloses. In this case, the adhesive side and the film side stick together during storage, making it difficult to remove when used.

The amount of the cellulose additive added is 1 to 5 parts by weight, preferably 2 parts by weight, based on ioo parts by weight of the ultraviolet curable heat-sensitive pressure adhesive.
~3 parts by weight 6 In the present invention, the film or sheet to which the pressure-sensitive adhesive layer is applied (hereinafter simply referred to as film) uses a heat-sensitive adhesive, so a film having heat resistance of 100°C or higher is used. . Therefore, the material of the film is polypropylene, polyester, cellulose acetate, etc., and the thickness is about 10 to 50 microns.

The method for producing the film or sheet according to the present invention includes coating the surface of the plastic film or sheet with a roll coater.
When a UV-curable heat-sensitive pressure-sensitive adhesive is applied using commonly used coating equipment such as a doctor knife coater, an extremely uniform UV-curable heat-sensitive pressure-sensitive adhesive layer is obtained, and the thickness of the adhesive layer is Although it varies depending on the purpose of use, it is usually about 5 to 100 microns, preferably about 10 to 50 microns.

The obtained film according to the present invention is then wound up into a roll to avoid the effects of ultraviolet rays during storage, and when used, the adhesive layer is coated on a metal plate, paper, plastic plate, etc.
Cover the surface to be painted with the film or sheet by adhering it to the surface to be painted, such as a wood board or cloth, while heating it to a temperature of 70°C to 100°C, and if necessary, apply it to the adhesive layer with a rubber roll, etc. After expelling the air bubbles contained in the
The adhesive is cured by irradiating the film with ultraviolet rays. When the film is then removed, the glossy surface of the film is transferred to the surface of the cured adhesive, creating an extremely beautiful mirror surface. Note that products with mirror surfaces are usually manufactured with a protective film pasted on them to prevent scratches.
In the case of the present invention, since the film coated with adhesive serves as a protective film as it is, it can be left without being removed after curing until use, and the conventional protective sheet is completely unnecessary. Furthermore, in the present invention, since the glossy surface of the film is directly transferred to the cured surface, for example, if the film is matte-treated or hairline-treated, the glossy surface of the film is directly transferred to the cured painted surface. It is possible to easily create matte or hairline cured coating surfaces. Further, the film according to the present invention can be applied not only to the entire surface processing but also to the surface processing and processing of spot portions. Furthermore, when a stretchable film such as a polypropylene film is used, it becomes possible to squeeze the adhesive without removing the film after it has hardened.

Next, a cross-sectional view of the film according to the present invention and an explanatory diagram during use are shown in FIGS. 1 and 2 (a), (b), and (C).
Shown as In the drawings, 1 is a film, 2 is an ultraviolet curable heat-sensitive adhesive layer, and 3 is a surface to be coated.

During storage, the effects of ultraviolet rays are avoided by winding the material into a roll as shown in FIG. In use, apply the adhesive layer 2 on the surface to be painted 3, and roll the hot roll 4 from the film side.
(Figure a). After covering the surface to be painted 3 with the ultraviolet-curable heat-sensitive pressure-sensitive adhesive film according to the present invention, the adhesive layer is cured by irradiating ultraviolet rays from the film side (Figure b), and then the 4 film layers are peeled off. A beautiful coating film consisting of an adhesive layer can be obtained on the surface to be painted (Figure 6)°.

The present invention will be explained in more detail with reference to Examples.

Example 1 First, methacrylic acid methyl ester monomer 4 in a molar ratio of 1
40 parts of toluene was added to a mixture of 0 parts and 20 parts of acrylic acid ethyl ester monomer, and a trace amount or more of benzoyl peroxide was mixed therein as a polymerization initiator, and the temperature was raised to 100°C.
Polymerize with 80 parts of the polymer having a degree of polymerization of 700 are taken, and 20 parts of tenben resin Picolite C135 (manufactured by Rika Vercules Co., Ltd.) is mixed therein and dissolved at 50°C to 60°C.

This polymer solidifies when the solvent dries, but when heated it becomes a sticky heat-sensitive adhesive, so adding the following ultraviolet curing agent composition to it can impart ultraviolet curing properties. I can do it.

Composition Weight ratio Urethane-modified acrylic oligomer 30 parts Dipentaerythritol hexaacrylate 10 parts Monomer Epoxy-modified diacrylate oligomer ~ 37
Part 2-Hydroxy-2-methyl-1-phenyl-1-one Part 3 The epoxy-modified diacrylate oligomer is solid and all liquid, but all are mixed and dissolved at a temperature of 60°C. What is necessary is just to mix a completely melted thing with the above-mentioned heat-sensitive pressure adhesive. In addition, the photopolymerization initiator 2-hydroxy-
2-Methyl-1-phenyl-1-one is mixed in last.

The mixing ratio is 30 parts of heat-sensitive adhesive and 30 parts of ultraviolet curing agent composition.
1 part solvent, 38 parts ethyl acetate, 2 parts nitrified cotton as an additive, and mix until a uniformly transparent solution is obtained.

When this solution was applied to a polyester film to a thickness of 20 microns and dried, the film could be rolled up without stickiness. This film was layered with a nameplate printed on an aluminum plate (painted side and printed side) and pressed with a hot rubber roll, but it adhered completely. The pressure bonding temperature is 90℃. Next 801/1c
When the film was peeled off by irradiating it with ultraviolet light using a high-pressure mercury lamp, an extremely beautiful and hard coating was obtained.

Example 2 20 parts of toluene was added to a mixture of 20 parts of methacrylic acid methyl ester monomer, 10 parts of acrylic acid monomer and 30 parts of acrylic acid ethyl ester monomer in molar ratio.

Add 20 parts of MEK, mix with it a trace amount or more of MEK peroxide as a polymerization initiator, and polymerize at a temperature of 80°C. When the degree of polymerization is 500, take 80 parts and mix with 20 parts of styrene derivative picolastic 0100. and 4
Dissolve at 0°C.

20 parts of this heat-sensitive pressure adhesive, 40 parts of an ultraviolet curing agent composition,
Further, 3 parts of MEK (methyl ethyl ketone) and 3 parts of ethyl cellulose were added as solvents and mixed until a uniform solution was obtained.

When this solution was applied to a polypropylene film to a thickness of 20 microns and dried, it could be rolled up as it was without stickiness.

This film was placed on a printed paper so that the adhesive layer overlapped with the paper, and the adhesive layer was pressed with a hot rubber roll to ensure complete adhesion. The pressure bonding temperature was 75° C., and ultraviolet rays were irradiated with a high pressure mercury lamp of 8011/lea, and when the film was peeled off, a coating film with extremely beautiful gloss was obtained.

(Effects) As described above, in the present invention, the ultraviolet curable heat-sensitive pressure adhesive layer provided on the film surface is applied to the aluminum plate using a hot rubber roll.
Paper, plastic board (all original boards.

By transferring the coating onto a printing plate (which may also include a printing plate) and irradiating it with ultraviolet rays, it is possible to create a beautiful, glossy film that is extremely dust-free and economical.

In particular, since the present invention uses a heat-sensitive adhesive layer as the adhesive layer, a film can also be formed on wood or fabric surfaces. In other words, when the previous invention was layered with a film, it easily penetrated wood and cloth because it was pressure-sensitive at room temperature, and it was not possible to form a uniform film due to air bubbles. The present invention has adhesive properties when stacked,
This is because because it is dry, there are no bubbles and the adhesive can be transferred very beautifully.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the film, and FIG. 2 is an explanatory view during use. 1...Film 2...Ultraviolet curable heat-sensitive pressure adhesive layer 3...
... Painted surface 4 ... Heat roll applicant Easy Chemical Industry Co., Ltd.

Claims (1)

[Claims] 1. A heat-sensitive pressure-sensitive adhesive film or sheet in which a layer of an ultraviolet-curable heat-sensitive pressure-sensitive adhesive is provided on the surface of a plastic film or sheet.