JPH0141496B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vacuum evaporation apparatus for producing a film with fewer scratches and pinhole defects in the metal evaporation film. Conventional metal-deposited films have been produced by vapor-depositing metals such as aluminum, zinc, chromium, tin, etc. onto plastic films, and then winding the films as they are.
These vapor-deposited films have been widely used for decoration such as gold and silver threads and labels, for miscellaneous goods, for packaging dried foods and frozen desserts, and for building materials for the purpose of insulation. However, although metallized films have excellent light blocking properties, they are hardly used in optical applications, such as plate making and graphic arts. The reason for this is that the metal film thickness of the metallized film is extremely thin, ranging from several tens of micrometers to several hundred micrometers, and can be scratched by the slightest external force, as well as pinholes caused by bumping of the metal during vapor deposition. Several tens of mμ~
Whereas a defect of several hundred micrometers is not a problem,
This is because these become fatal defects in applications that utilize optical properties. An analysis of such optical defects (hereinafter referred to as pinholes) in the deposited film revealed that some are due to bumping of the deposited metal, some are caused by adhering dust that acts as a masking effect and prevents the deposited metal from adhering, and some are caused by scraping off for some reason after the deposition. I found out that there were some things that were done. The incidence of the first two cases is relatively small, and can be dramatically reduced by taking countermeasures for each. For example, to prevent bumping of vapor-deposited metal, increase the purity of the metal to be vaporized,
It can be reduced by selecting the material of the crucible to be heated, the rate of temperature increase, the temperature during vapor deposition, the distance between the base material and the crucible, etc. Prevention of pinholes due to attached dust can be greatly reduced by cleaning or wiping the film to be deposited, cleaning the inside of the vacuum deposition chamber, etc. In addition, in the case of the latter, which is scraped off for some reason after vapor deposition, that is, when scratches occur due to rolls that come into contact during the transportation process up to winding or minute slips during winding, resulting in pinholes, Until now, few improvement methods have been proposed. In addition, although it is theoretically not impossible to arrange and wind up the rolls so that the evaporation surface does not come into contact with the roll after evaporation, it is practically impossible due to the constraints of being inside a vacuum chamber and the purpose of measuring tension, metal film thickness, etc. For this reason, conventional winding type vacuum evaporation machines are configured so that the evaporation surface and several rolls come into contact with each other. Furthermore, even if the rolls are arranged in a vapor deposition machine so that the vapor deposition surfaces do not come into contact with each other at all, it is unavoidable that the vapor deposition surface will come into contact with the back surface of the material when winding the vapor deposited film. Scratches or pinholes due to pressure cannot be avoided due to tension fluctuations, slight eccentric movements of the winding shaft, and changes in contact pressure due to uneven thickness of the vapor-deposited film. (Of course, if microscopic foreign matter such as dust adheres to the surface of the film at this time, this kind of defect will be further exacerbated.) Therefore, the present inventors have developed a method to prevent the occurrence of pinholes and to create a metal film that can be sufficiently applied to optical applications. As a result of studies aimed at obtaining a vapor-deposited film, the present invention was arrived at. That is, the present invention provides a layered film characterized in that after metal vapor deposition is carried out while a film-like material is running in a vacuum, the vapor-deposited surface is overlapped with a separately prepared protective sheet in the same vacuum chamber and wound up. In the manufacturing method and the device for metal vapor deposition of the film in vacuum, at least one device for unwinding the protective sheet separately from unwinding the adherend layer film and winding up the metal vapor deposition layer is installed in the same vacuum chamber, and the protective sheet This is a device for superimposing and winding the vapor-deposited film and the vapor-deposited film. The present invention will be described in detail below with reference to the drawings, but the present invention is not limited thereto. Figure 1 shows a device that performs vapor deposition while running a film-like material in a vacuum, and then winds the film by overlapping it with a separately prepared protective sheet in the same vacuum chamber as the vapor deposition surface. 2 is a guide roll for conveyance, and 3 is a cooling roll. The metal is steamed from the crucible 4 and adheres to the film 5 during running. The vapor-deposited film is conveyed by a roll that contacts the vapor-deposited surface, such as 6, or a roll that contacts the non-evaporated surface, such as 7.
It is wound up on the winding shaft. A general vapor deposition machine performs vapor deposition using the process described above. In addition, during the conveyance process, 2′,
It is also possible to install Nipprol expander rolls such as 6'. In addition to these conveying and winding systems of the present invention, a sheet B for protecting the deposition surface is wound around a winding shaft A provided separately, and a sheet B for protecting the deposition surface is passed through guide rolls C to guide the film on which the deposition surface of the film that has already been deposited is 6. It is wound onto the winding shaft 8 while being overlapped and conveyed before contacting the roll. A nip roll D may be attached to the protective sheet B and the vapor-deposited film 6, if necessary. FIG. 2 shows an apparatus for directly winding the film 6 after vapor deposition onto a winding shaft 8, and at the same time winding the film 6 overlappingly with another unwinding shaft A. Further, FIG. 3 shows a superimposed film obtained by the present invention. The film to be vapor-deposited used in the present invention is not particularly limited as long as it can be vapor-deposited. In other words, plastic films such as cellophane, triacetate film, polyethylene terephthalate film, polyethylene film, polypropylene film, nylon film, vinyl chloride film, polyvinyl alcohol film, polycarbonate film, Teflon film, polystyrene film, and composite films and coatings based on these films. Tudo film, surface-treated (for example, embossed) film, etc. are used. Materials used for vapor deposition include aluminum,
Even simple metals such as zinc, tin, copper, lead, selenium, bismuth, antimony, silver, gold, chromium, nickel, iron, and cobalt, alloys such as nichrome and stainless steel, and compounds such as CdS and M ₈ F ₂ good.
As the evaporation method, any method such as induction heating crucible method, resistance heating boat method, electron beam heating crucible method, vacuum evaporation, sputtering method, etc. can be adopted. The protective sheet to be coated on the deposition surface may be a general plastic film, such as a film made of polyethylene terephthalate, polyethylene, polypropylene, nylon, polyvinyl alcohol, vinyl chloride, polycarbonate, polystyrene, Teflon, etc., or a composite film made of these base materials. There are coated films, such as adhesive films. The film may be used as it is or may be charged. Specifically, for vacuum deposition of polyethylene terephthalate film, the same type of polyethylene terephthalate film with less surface roughness may be used, but generally softer polyprene film, polyethylene film, polyvinyl alcohol film, etc. are used as the protective sheet. do. In particular, in order to eliminate even minute defects, it is best to use a film made by laminating polypropylene or polyester with a film that has been treated with adhesive or slightly adhesive. In the case of polypropylene film or polyethylene film that does not have very strong adhesion to metal, use a protective film that has been processed to have low adhesion. If it is clear that surface materials such as lubricants and adhesives of the protective sheets will adhere to the protective sheets due to overlapping and adversely affect post-processing, use a combination of materials that will not be affected by these materials. The film obtained by the method according to the invention is characterized by being superimposed with another protective sheet in a vacuum chamber during vapor deposition, as described above. This can prevent pinhole defects that occur during deposition. Furthermore, this film is in roll form and is advantageous in preventing scratches from occurring due to surface pressure during transportation and standing after being taken out into the atmosphere. It is extremely effective against pinholes caused by scratches that occur when the vapor deposition surface comes into contact with the transport roll during roll transport. In other words, during coating, laminating, etc., these defects can be avoided by leaving the protective sheet on the vapor deposition surface until just before coating and laminating, and then peeling off the protective sheet just before the coating and laminating rolls. This is because it can be prevented. The invention is illustrated by the following examples. Example 1 A polyethylene terephthalate film (“Lumirror” manufactured by Toray Industries, Inc.) with a thickness of 50 microns was coated with aluminum to a thickness of 100 mμ in a vacuum of 1 × 10 ^-4 Torr using the apparatus shown in Figure 1. The adhesive surface of a film that was vacuum-deposited and treated with an adhesive strength of 20 g/cm using a 20-micron-thick polyethylene film base installed in an unwinding machine separate from the film to be deposited, which was installed in the same vacuum chamber. was superimposed on the vapor-deposited surface and wound up. As Comparative Example 1, a polyethylene terephthalate film with a thickness of 50 microns was vacuum-deposited with aluminum to a thickness of 100 mμ using the same vacuum evaporator described above under a vacuum degree of 1×10 ^-4 Torr, and then wound as it was. . 20 cm of each of the films of Example 1 and Comparative Example 1
It was cut out to a size of 20cm x 20cm and the number of pinhole defects was examined on a light table. The results are shown in Table 1.

[Table] Example 2 A polyethylene terephthalate film (Lumirror manufactured by Toray Industries, Inc.) with a thickness of 100 microns was vacuum-coated with aluminum to a thickness of 70 mμ at a vacuum level of 2 × 10 ^-4 Torr using the same equipment as in Example 1. After vapor deposition, an unstretched propylene film with a thickness of 25 microns was stacked and wound up. Table 2 shows the results of Comparative Example 2, which was a film wound without overlapping, and inspected for pinhole defects under a light table in the same manner as in Example 1.

[Table] Example 3 A triacetate film with a thickness of 80 microns was coated with a vacuum degree of 5× using the same equipment as in Example 1.
Aluminum was deposited to a thickness of 50 μm under 10 ^-4 Torr, and a polyvinyl alcohol film of 15 μm thickness was layered and rolled up. Comparative Example 3 is a film in which the same film was vapor-deposited and wound as it was, and evaluated using the method of Example 1. Table 3 shows the results.

[Table] Example 4 A protective layer was provided on the metal-deposited surface of the film obtained in Example 1 and the film obtained in Comparative Example 1 using a gravure roll coater. The paint is 20 parts VAGH (vinyl resin manufactured by UCC), 40 parts toluene, and 40 parts MEK.The gravure roll has a 180 mesh depth of 30 microns and is pyramid-shaped, and the coating thickness is approximately 1.
g/m ² , drying temperature 80°C, and winding speed 50 m/min. Of the guide rolls up to coating, five come into contact with the deposited film. After the film of Example 1 was unwound, the film was transported in a stacked state, and just before coating, the cover film was peeled off and the film was rolled up and removed. The film of Comparative Example 1 was transported and coated in the usual manner. Both coated films were inspected for pinholes using the same evaluation method as in Example 1, and the results are summarized in Table 4.

【table】 [Brief explanation of drawings]

1 and 2 show a vacuum evaporation apparatus according to the present invention. FIG. 3 shows a laminated film obtained according to the present invention. 1: Unwinding shaft of film to be deposited, 2: Guide roll, 3: Water-cooled roll, 4: Evaporation crucible, 5: Film to be deposited, 6: Metal surface contact guide roll, 7:
Non-metallic surface contact guide roll, 8: Winding shaft, A: Unwinding shaft of protective sheet, B: Protective sheet, C: Guide roll, D: Nip roll, 9: Nip roll,
10: Expander roll, 11: Vacuum chamber, 1
2: Deposited film, 13: Metal deposited layer, 14:
protective sheet.

Claims (1)

[Claims] 1. Overlapping characterized by depositing metal while running a film-like material in a vacuum, and then overlapping the deposited surface with a protective sheet separately prepared in the same vacuum chamber and winding it up. Film manufacturing method. 2. In an apparatus for metal-depositing films in vacuum, at least one apparatus for unwinding a protective sheet in addition to unwinding, metal-depositing, and winding of the film to be deposited is installed in the same vacuum chamber, and the protective sheet and the A device that overlaps and winds the film to be deposited.