JPH0317902B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for forming an organic thin film on the surface of a substrate such as a plastic film or sheet.

BACKGROUND OF THE INVENTION Recently, coatings of ultraviolet curable resins have been increasingly used for surface hardening of materials such as plastic films that cannot be treated at high temperatures. By the way, the conventional coating method involves dissolving the main component oligomer and photopolymerization initiator in a solvent or liquid monomer, applying this to the surface of the base material, drying it, and then performing ultraviolet irradiation treatment. It consists of hardening.

In addition, for decorative plastic products such as gold paper and silver paper, a thin film of metal such as Al or Cr is formed on a transparent plastic substrate by vacuum evaporation or sputtering, and then the method described above is applied. and forms an organic protective film. In some applications, an organic film is first formed on the surface of the substrate and then a metal film is formed in order to improve the adhesion between the substrate and the metal thin film or to adjust the color. Furthermore, an organic film may be formed again on the surface.
In such a case, in the conventional method as described above, it is necessary to perform the coating step in the atmosphere and the metal film forming step in vacuum two or more times, which poses a problem of poor mass productivity. Furthermore, since conventional methods use organic solvents, they are flammable and toxic, and pose a high risk of fire and pollution. Furthermore, conventional methods have the disadvantage that it is difficult to uniformly form thin films.

Problems to be Solved by the Invention The present invention solves the following problems in conventional methods: (1) flammability and toxicity problems associated with the use of organic solvents, (2) difficulties in forming a uniform thin film, and (3) ) The object of the present invention is to provide a new method for forming organic thin films that can overcome the disadvantages of mass production.

Means for Solving the Problems In order to achieve the above object, the method for forming an organic thin film according to the present invention involves separately applying an oligomer or monomer of an ultraviolet curable resin and a photopolymerization initiator to the surface of a substrate in vacuum. It is characterized in that it is evaporated from an evaporation source to precipitate a mixture having a desired composition on the surface of the substrate, and then cured by ultraviolet irradiation treatment.

Examples of oligomers of ultraviolet curable resins that can be used in the method of the present invention include epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate, polyol acrylate, melamine acrylate,
Unsaturated polyester etc. can be used, and various acrylate and methacrylate monomers can also be used. Moreover, oligomers can be preferably used from the viewpoint of ease of vapor deposition and curing speed.

As the photopolymerization initiator, commonly used ones such as benzyl, benzophenone, benzoin, and alkyl ether can be used.

Effect By having the above structure, the method of the present invention can form an organic thin film without using an organic solvent, and since it is a vacuum process, it uses the same equipment as the process for forming the metal layer. carried out using
It can be manufactured in an integrated manner, prevents dust from entering, and can form extremely thin films.

In addition, in the method of the present invention, it is also possible to evaporate two or more types of oligomers or monomers using a plurality of evaporation sources to obtain a mixture thereof or an evaporated product having a multilayer structure.

Furthermore, the method according to the present invention can also form fine patterns by using a mask during ultraviolet irradiation, and can also be applied to forming insulating films for ICs and manufacturing capacitors.

EXAMPLE An example of an apparatus implementing the method of the present invention will be described below with reference to the accompanying drawings.

The illustrated apparatus has two vacuum vessels 1, 2, vacuum vessel 1 is used to deposit metals, while vacuum vessel 2 is used to form organic thin films according to the invention, and both It is configured so that the steps can be performed continuously. That is, in the drawing, a plastic film 3 to be processed is conveyed between an unwinding roller 4 provided in a vacuum container 1 and a take-up roller 5 provided in a vacuum container 2, and 6 and 7 are cooling cans, respectively. 8 and 9 are guide rollers; 10 is a partition wall 1 between both vacuum containers 1 and 2;
1 is a passage opening in a plastic film 3 provided in FIG. Further, inside each vacuum vessel 1, 2, an electron beam evaporation source 12, a resin oligomer evaporation source 13, and a photopolymerization initiator evaporation source 14 are provided, respectively, facing the cooling cans 6, 7 combined. There is. Further, as shown in the figure, a plurality of ultraviolet generators (for example, high-pressure mercury lamps) 15 are arranged adjacent to the cooling can 7 in the vacuum container 2 . The vacuum vessels 1 and 2 are connected to an exhaust system (not shown) via exhaust ports 1a and 2a, respectively.

In the operation of the apparatus configured as described above, the deposition of a metal film within the vacuum vessel 1 is not directly related to the present invention, but the operation of the electron beam evaporation source 12 causes the deposition of a metal film, for example, on a plastic film on which an aluminum film has been deposited. 3 is a guide roller 8, a passage opening 1
0 and guide rollers 9 along the circumference of the cooling can 7 . Two independent evaporation sources 1
3 and 14, the oligomer and the photopolymerization initiator are evaporated to a desired composition ratio. In this case, since the evaporation rate varies depending on the oligomer and photopolymerization initiator used, the temperatures of the evaporation sources 13 and 14 are controlled and adjusted while taking these factors into consideration. After the evaporated material is deposited on the plastic film 3 to a predetermined thickness, the high-pressure mercury lamp 15 is turned on to irradiate it with ultraviolet rays to perform a curing process.

In the illustrated apparatus, after first forming a resin film on the plastic film 3 in the vacuum container 2,
It is also possible to form a metal film such as aluminum in the vacuum container 1 and then form an organic film thereon again, and it is also possible to form a multilayer film of these. It is also possible to modify the illustrated apparatus to configure it in an in-line manner so that each film-forming layer can be sequentially processed in each of the sequentially arranged processing chambers.

Next, an experimental example will be described in which aluminum was vapor-deposited on a polyester film using the illustrated apparatus and an organic film was formed on the surface thereof.

Base material: 12μm thick polyester film Resin oligomer: 100 parts of epoxy acrylate (Showa Kobunshi Co., Ltd. VR-90) Photopolymerization initiator: 3 parts of benzoin alkyl ether Resin vapor deposition film thickness: 0.5μm Degree of vacuum: ×10 ^{- 3} Pa Film running speed: 0.1m/min Ultraviolet irradiation: 160W, 5 minutes On the polyester film under the above conditions
An organic film was formed on the surface of a semi-transparent film with aluminum vapor deposited to a thickness of 200 Å, and the film hardness was tested to be 2H in the Empin hardness test (load of 500 g). On the other hand, the hardness of the aluminum film before forming the organic film was 3B. From this, it is recognized that the organic film formed by the method according to the present invention can function satisfactorily as a protective film.

Effects As explained above, since the method of the present invention is a vacuum process, the organic film can be continuously formed using the same equipment used in the process of forming the metal layer, which greatly improves productivity. Furthermore, an extremely thin film can be uniformly formed. Furthermore, since no organic solvent is used and the treatment is carried out in a vacuum container, there is no risk of ignition or pollution, and moreover, it is possible to prevent foreign matter such as dust from entering.

[Brief explanation of the drawing]

The drawing is a schematic cross-sectional view showing an example of an apparatus implementing the present invention. In the figure, 2... vacuum container, 3... base material, 13, 14...
Evaporation source, 15...UV generator.

Claims (1)

[Claims] 1. Evaporate the oligomer or monomer of the ultraviolet curable resin and the photopolymerization initiator from separate evaporation sources onto the surface of the substrate in vacuum, precipitate a mixture with the desired composition on the surface of the substrate, and then irradiate it with ultraviolet rays. 1. A method for forming an organic thin film, comprising curing by treatment.