JPH0344142B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for producing a metal-deposited film for microwave ovens.

[Prior art] Metal-deposited films have been used for food packaging containers such as fresh foods, cooked foods, and semi-cooked foods, station lunches, disposable lunch boxes for caterers, and simple tableware to increase product value. There is.

On the other hand, it has become popular to heat and cook packaged foods such as those described above using a microwave oven.

However, there is a problem in that when a container made of metallized film is heated in a microwave oven, sparks are generated.

Therefore, it has been proposed to stretch the metal-deposited film in a softened state vertically and horizontally to divide the metal-deposited layer into minute regions to prevent sparks.

However, when using this stretching method, there are problems such as whitening of the metal vapor deposited layer, which impairs the metallic luster, and slippage occurring at the interface between the film and the metal vapor deposited layer, resulting in extremely poor adhesion.

[Object of the Invention] In view of the above-mentioned points, the object of the present invention is to provide a method for manufacturing a metallized film suitable for use in a microwave oven without impairing the metallic luster, durability, etc. of the metallized film. It is.

[Structure of the Invention] The present invention involves forming a metal vapor deposited layer on the entire surface of a synthetic resin film on which a corrosion resistant printed pattern is formed, and forming a corrosion resistant film on the surface of the metal vapor deposited layer. The metal vapor deposition layer is formed so as to be divided into mutually discontinuous small regions separated by minute gaps, and then treated with an etching solution to remove the metal vapor deposited layer in the areas where no corrosion resistant film is present. The film surface is regularly divided into mutually discontinuous small regions, and each small region has an area of 0.01 to 25 ^mm2 ,
The present invention relates to a method for producing a metal-deposited film for microwave ovens, characterized in that a metal-deposited layer is formed with a gap between adjacent small regions of 0.1 to 2 mm.

[Effects of the Invention] In the present invention, the metal vapor deposited layer divided into small regions is formed by the etching method as described above, so that whitening due to stretching as in the conventional example,
A metal-deposited film for microwave ovens which has no possibility of slippage at the interface between the film and the metal-deposited layer, has excellent metallic luster and durability, and is prevented from sparking can be obtained.

Furthermore, the present invention provides the following unique effects. In other words, in the conventional method, a metal vapor deposited layer is provided on the film surface, and the metal vapor deposited layer is divided into small regions by stretching and creating cracks in the metal vapor deposited layer. It is difficult to form a pattern (including letters, figures, symbols, etc., the same shall apply hereinafter), or to form a window part without a metal vapor deposition layer so that the inside can be seen through when used as a container. or virtually impossible.

On the other hand, in the present invention, when it is desired to form a metal vapor deposited layer divided into small regions into a pattern, the patterned portions are covered in advance with a corrosion-resistant film (divided into small regions as described above). If a window portion is formed, it is sufficient that the portion is not covered with a corrosion-resistant film, and the pattern of the metal vapor deposited layer and the window portion can be formed as desired.

Further, in the present invention, by using a synthetic resin film provided with a corrosion-resistant printed pattern, it is possible to obtain a combination pattern of this printed pattern and the metal vapor deposition pattern. However, in the conventional example, it is difficult to obtain a metal vapor deposition pattern as described above, and furthermore, the printed pattern is distorted due to stretching, so it is extremely difficult to obtain a combination of a printed pattern and a metal vapor deposition pattern as in the present invention. .

As described above, according to the present invention, it is possible to obtain a metal-deposited film for microwave ovens which has an extremely excellent decorative effect.

[Embodiment] Next, the method of the present invention will be explained based on the drawings.

FIGS. 1A and 1B, and FIGS. 2A and 2B are explanatory diagrams showing an embodiment of the method of the present invention in the order of steps, and FIGS. 1A and 2A show film-like products obtained in each step. FIGS. 1B and 2B are enlarged partial cross-sectional views, respectively. Note that since FIGS. 1A to 1B and 2A to 2B illustrate the metal vapor deposited layer divided into small regions, the corrosion-resistant printed pattern is omitted in these drawings.

First, as shown in FIGS. 1A and 1B, a metal vapor deposited layer 2 is formed on the entire surface of one side of a synthetic resin film 1, and then a corrosion-resistant film 3 is formed discontinuously and separated from each other by a minute gap W. It is formed so as to be divided into a large number of small regions 3a.
In FIG. 1A, the portions where the corrosion-resistant film 3 is not present form a lattice-like pattern, and the metal vapor deposited layer 2 is exposed in those portions. As will be described later, the corrosion-resistant film 3 is divided into small regions 3a as described above.
may be formed into a pattern as a whole.

Next, as shown in FIGS. 2A and 2B, when the film-like material obtained above is subjected to an etching process, small areas 3 not covered with the corrosion-resistant film are formed.
The metal vapor deposited layer 2 in the gap M between a is dissolved and removed, and as a result, a metal vapor deposit layer 4 is formed in which a large number of mutually discontinuous small regions 4a separated by the gap W are aggregated. , the metal-deposited film for microwave ovens of the present invention can be obtained.

The size of the divided small regions 4a of the metal vapor deposited layer 4 is preferably 25 mm ² or less, particularly 1 mm ^{2 or} less, from the viewpoint of preventing sparks. Small area 4a
Although the lower limit of the area is not particularly limited, it is preferably 0.01 mm ² or more in order to obtain good metallic luster and to facilitate the formation of the small area 4a.
Although it is advantageous in manufacturing that the planar shapes of the small regions 4a are all the same, they may be different. The gap W between adjacent small areas 4a is preferably in the range of 0.1 to 2 mm, particularly in the range of 0.1 to 0.2 mm. If the gap W is smaller than 0.1 mm, sparks cannot be sufficiently prevented, and the deposited metal in the gap cannot be completely removed during manufacturing. If the gap W is larger than 2 mm, the metallic luster will not be sufficient.

Metal vapor deposition may be carried out by a conventional method, and vacuum vapor deposition, sputtering, ion plating, etc. are all employed. The type of metal to be deposited is not particularly limited, and for example, aluminum, zinc, tin, copper, nickel, chromium, gold, silver, platinum, alloys of two or more of these metals, and the like can be used as appropriate. The thickness of the metal vapor deposition layer 2 is approximately 0.02 to 0.2 μm.

The corrosion-resistant film 3 may normally be formed using a corrosion-resistant printing ink, but it may also be formed using a photosensitive resin paint. The coating method for the corrosion-resistant film 3 is not particularly limited, and may be carried out by an appropriate method such as silk screen, roll printing, or gravure printing. The pattern of the corrosion-resistant film 3 is not limited to the patterns shown in FIGS. 1A and 1B, but may be appropriately determined in consideration of the division pattern of the metal vapor deposited layer 4 in the final product.

The thickness of the corrosion-resistant film 3 is usually 0.5 to 3 μm, preferably
It is considered to be 0.5 to 1.5 μm. If the thickness of the corrosion-resistant film 3 is less than 0.5 μm, a coating layer with a uniform thickness may not be obtained, and there is a risk that some areas may have insufficient corrosion resistance; In this case, it becomes difficult to form the corrosion-resistant film 3 in a fine pattern.

A normal etching solution is used,
For example, aqueous solutions of acids such as hydrofluoric acid and sulfuric acid, and alkalis such as sodium hydroxide and potassium hydroxide are used as appropriate depending on the type of metal to be deposited.

The etching treatment can be carried out by either a dipping method or a showering method, and may be carried out by heating if necessary.

The synthetic resin film 1 can be used without particular limitation as long as it has heat resistance and corrosion resistance to the extent that it does not easily deform when heated in a microwave oven, such as polyester, polypropylene,
Examples include polycarbonate. film 1
The thickness is appropriately selected from a range of approximately 6 μm to 3 mm depending on the intended use of the product. The term "film" in the present invention includes such thick sheet-like materials. The film 1 may be transparent or opaque. When used in a manner in which the metal vapor deposited layer 4 is viewed through the film 1, it is made transparent.

It is usually preferable to provide a top coat layer on the metal vapor deposited layer 4 side.

Next, a combination of a metal vapor deposition pattern and a printed pattern will be explained.

FIG. 3 is a plan view showing an example of the embodiment, and FIG. 4 is an enlarged sectional view taken along the line X-X of FIG.
FIG. 5 is an enlarged sectional view taken along the line Y--Y in FIG. 3. FIG. 3 corresponds to the top view of the film in FIGS. 4 and 5. The film shown in FIGS. 3 to 5 consists of a silver part 10, a red metallic luster part 11, a blue metallic luster part 12, a blue part 13, and a colorless transparent part 14.

The silver portion 10 is provided with only the metal vapor deposited layer 4 exhibiting a silver color. The red metallic gloss portion 11 is provided with a red ink layer 20 and a metal vapor deposition layer 4. The blue metallic gloss portion 12 is provided with a blue ink layer 21 and a metal vapor deposition layer 4. In the blue portion 13, only the blue ink layer 21 is provided. Colorless transparent part 14
is a part without any layer. Note that a corrosion-resistant film 3 is provided on the back surface of each of the metal vapor deposited layers 4. Although not shown, all of the metal vapor deposited layer 4 is divided into small regions 4a as shown in FIGS. 2A and 2B.

The film is manufactured through the steps shown in FIGS. 6-8. Note that FIGS. 6 to 8 each correspond to an enlarged sectional view taken along the line X--X in FIG. 3.

First, as shown in FIG. 6, a red ink layer 20 and a blue ink layer 21 are placed on a transparent film 1.
form. Corrosion-resistant printing ink is used to form these ink layers.

Next, as shown in FIG. 7, a metal vapor deposition layer 2 is formed on the entire surface of the film on which the ink layer is provided.

Next, as shown in FIG. 8, a corrosion-resistant film 3 is formed only on the portions of the metal vapor deposited layer 2 that are to be left. This corrosion-resistant film 3 is formed into a fine pattern as shown in FIGS. 1A and 1B. Then, when etching treatment is performed, corrosion resistant film 3 is formed.
The parts of the metal vapor deposited layer 2 that are not covered with the corrosion resistant film 3 are completely dissolved and removed, and the parts of the metal vapor deposited layer 2 that are covered with the corrosion resistant film 3 corresponding to the division pattern of the corrosion resistant film 3 are also dissolved and removed. The metal vapor deposited layer 4 is divided into discontinuous small regions 4a as shown in FIGS. 2A and 2B. In this way, the metallized film shown in FIGS. 3 to 5 is obtained.

In this way, it is possible to obtain a film that does not generate sparks even when heated in a microwave oven and has an excellent decorative effect. This film is also provided with a top coat layer on the side where the metal vapor deposited layer 4 is located, depending on the purpose.

The metallized film of the present invention can be suitably used as a material for various packages and containers for microwave ovens, either by itself or by laminating with other films.

[Example] Next, the present invention will be explained with reference to Examples.

Example 1 A metallized film shown in FIGS. 3 to 5 was manufactured.

First, as shown in FIG. 6, a red ink layer 20 and a blue ink layer 21 were formed by gravure printing on one side of a polyester film having a thickness of 12 μm using a corrosion-resistant gravure ink.

Next, as shown in FIG. 7, aluminum was vacuum-deposited on the entire surface of the film on which the ink layer had been formed, to form an aluminum-deposited layer 2 having a thickness of 0.50 μm.

Next, as shown in FIG. 8, a corrosion-resistant gravure ink is printed on the portions of the aluminum vapor deposited layer 2 that will not be dissolved and removed later, as shown in FIGS. 1A and 1B.
A corrosion-resistant film 3 having a pattern as shown in the figure was formed. The small area 3a of the corrosion-resistant film 3 is a square with a size of 1 mm x 1 mm, and the gap W between adjacent small areas 3a is
The thickness was 0.2 mm and the thickness was 1 μm.

Then, the above film-like material was diluted with hydrofluoric acid.
It was etched by immersing it in a wt% solution, then thoroughly washed with water, and then dried. Through this etching process, the parts of the aluminum vapor deposited layer 2 that are not covered with the corrosion resistant film 3 are completely dissolved and removed, and the parts of the aluminum vapor deposited layer 2 that are covered with the corrosion resistant film 3 are also formed into the divided pattern of the corrosion resistant film 3. A discontinuous small region 4a where the corresponding portion is dissolved and removed
An aluminum vapor deposited layer 4 divided into two parts was formed.

Next, a 3 μm thick top coat layer was formed on the side of the aluminum vapor deposited layer 4 using a melamine-alkyd resin paint.

When the film thus obtained was placed in a microwave oven (high-frequency output 600W, oscillation frequency 2450MHz) and microwaves were applied, no sparks were generated.

Example 2 In Example 1, the thickness of the corrosion-resistant film 3 was set to 0.5 μm,
The size of the small area 3a is 0.2 mm x 0.2 mm, and the gap W is 0.1
A metal-deposited film was produced in the same manner as in Example 1 except that the thickness was set to mm.

This film also did not generate any sparks in the microwave.

[Brief explanation of drawings]

FIGS. 1A and 1B, and FIGS. 2A and 2B are explanatory diagrams showing an embodiment of the method of the present invention in the order of steps, and FIGS. FIG. 1B and FIG. 2B are respectively enlarged partial cross-sectional views of the object; FIG. 3 is a plan view of a metal-deposited film obtained by another embodiment of the method of the present invention; FIG. 4; is an enlarged sectional view taken along the line X-X of Fig. 3, Fig. 5 is an enlarged sectional view taken along the line Y-Y of Fig. 3, and Figs.
FIG. 5 is an enlarged cross-sectional view of a film-like material obtained in each process for obtaining the film shown in FIGS. (Main symbols in the drawing), 1...Synthetic resin film,
2... Metal vapor deposition layer, 3... Corrosion resistant film divided into small regions, 3a... Small region of corrosion resistant film, 4... Metal vapor deposition layer divided into small regions, 4a... Small region of metal vapor deposition layer.

Claims (1)

[Scope of Claims] 1. A metal vapor deposited layer is formed on the entire surface of a synthetic resin film on which a corrosion resistant printed pattern is formed on the side of the printed pattern, and a corrosion resistant film is formed on the surface of the metal vapor deposited layer so that the corrosion resistant film has minute particles. The film surface is divided into discontinuous small regions separated by gaps, and then treated with an etching solution to remove the metal vapor deposited layer in the areas where no corrosion resistant film is present. forming a metal vapor deposition layer on top of the metal evaporation layer, which is regularly divided into mutually discontinuous small regions, each of which has an area of 0.01 to 25 mm ² , and a gap between adjacent small regions of 0.1 to 2 mm; Manufacture of a metal-deposited film for microwave ovens characterized by the following. 2. The method according to claim 1, wherein each of the small regions has an area of 0.01 to 1 mm ² and a gap between adjacent small regions is 0.1 to 0.2 mm.