JP2003326657A - Plastic film or plastic sheet for molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic film or a plastic sheet for molding, which can be produced in a small quantity, and makes it difficult to cause molding failures such as cracking and peeling when a plastic product is molded by vacuum or air-pressure molding. <P>SOLUTION: This plastic film or the plastic sheet for the molding is used as a molding material for the plastic product molded by the vacuum or air- pressure molding; and a color coating film (4), which is composed of a coating agent (3) in which a polyester resin serves as a vehicle, is formed at least on one side of a base film (2) or a base sheet, which is composed of a polyester resin. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic film or sheet for molding used as a molding material for a plastic product by vacuum or pressure molding, and is particularly suitable for molding a packaging container such as a blister pack. is there.

[0002]

2. Description of the Related Art Plastic film (sheet) for molding
Is widely used as a molding material for various packaging containers such as blister packs, press-through packs, thermoford packs, and contour package. And, as its material, it is excellent in heat resistance, weather resistance and chemical resistance, has high transparency, is harmless in food hygiene, and has excellent characteristics that it does not generate toxic gas when incinerated Resin is used.

Blister packs used for packaging daily necessities and toys, and press-through packs used for packaging tablets and capsules are generally colorless and transparent packaging containers so that the contents can be observed from the outside. However, recently, colored and transparent packaging containers have been developed for the purpose of preventing discoloration and deterioration of the contents due to sunlight (ultraviolet rays) and imparting a beautiful appearance.

Further, a thermoford pack in which a plastic film for molding is formed in a cup-shaped container and a solid, liquid or powder food such as yogurt, jelly or pudding is filled with the lid, or a high-grade biscuit to be put in a cosmetic box.・ Made into a saucer shape that matches the contours of products such as high-grade chocolate, and the contour package that also serves as a cushioning material and fixing material is colored according to the image of the product.

In this case, if the molding plastic film is colored after being vacuum-molded or pressure-molded into a packaging container shape, the number of steps of each molded product increases and the molding plastic film is colored in advance. Well,
Vacuum forming or pressure forming of this is performed to form a packaging container.

In the case of producing such a colored plastic film for molding, conventionally, a pigment or dye is mixed with a polyester resin for coloring, and the colored polyester resin is extruded to form a film. is doing.

[0007]

However, in the case where the polyester resin is colored and formed into a film in this manner, a general molding machine has a minimum production lot of several tens of tons. There was a problem that it was not suitable for small-scale production.

For this reason, there has been proposed a technique for coloring a polyester resin film by using a transfer sheet having a colored layer formed on one side thereof or a coloring color film so as to cope with a small amount of production.

The transfer sheet is formed by printing or painting a colored layer in which a pigment or a dye is dispersed on one surface of a release film. The colored layer of the transfer sheet is in contact with the polyester resin film to be colored. The colored layer is colored by peeling off the release film after transferring the colored layer to the base film by heating the colored layer on the base film.

The color film for coloring is formed by forming a coloring layer in which a pigment or a dye is dispersed on one side of a cover film. The coloring layer is sandwiched between the polyester resin film to be colored and the cover film. The color film is laminated to color the plastic film for molding.

However, when a packaging container such as a blister pack is molded by vacuum or pressure molding using the colored plastic film for molding as described above, one of the base film or the cover film may be cracked or the base film may be cracked. And the colored layer, between the colored layer and the cover film, and between the base film and the cover film, a molding defect such as peeling is likely to occur, resulting in a poor yield. In particular, the blister pack and the contour package have a problem that cracks and peeling are likely to occur at the corners where the vertical surface of the unevenness and the horizontal surface intersect.

[0012] Therefore, the present invention provides a plastic film or sheet for molding which can be produced in a small amount and is less likely to cause molding defects such as cracking and peeling when molding plastic products by vacuum or pressure molding. It is a technical issue.

[0013]

In order to solve this problem, the present invention provides a molding plastic film or sheet used as a molding material for a plastic product by vacuum or pressure molding, which comprises a base film or a polyester resin. The sheet is characterized in that a color film made of a coating agent containing a polyester resin as a vehicle is formed on at least one surface of the sheet. Note that the film and the sheet may be distinguished by the thickness, but are not strictly distinguished, and hence in the present specification, both are simply referred to as “film”.

The plastic film for molding of the present invention is
A polyester resin color coating is formed on at least one surface of a base film made of polyester resin. As the polyester resin of the base film, for example, PET (polyethylene terephthalate) is used. As a coating agent for forming a color film, a polyester resin paint or a polyester resin ink in which a pigment / dye is dispersed in a vehicle composed of a polyester resin and a solvent is used. Therefore, since the color film is formed by painting and printing such paints and inks, not only can small-scale production be possible, but the polyester resin used in this vehicle has a composition that is a base material. It is preferable to use a film having a composition close to that of the film. Further, when a large amount of an organic solvent is used in the polyester resin paint or the polyester resin ink, there is a fear of environmental pollution, and therefore it is preferable to use a water-soluble / water-dispersible polyester resin.

When a packaging container such as a blister pack is manufactured using this plastic film for molding,
The plastic film for molding is heated to a predetermined temperature and set in a mold, and vacuum or compressed air molding is performed by using air pressure to match the mold, and then the film is cooled and taken out.

In this case, in the plastic film for molding, both the base film and the color coating are formed of polyester resin, and first, the base film and the color coating are softened at the same temperature. Then, when molding by air pressure, the deformation behavior of the base film and the color coating with respect to the stress acting on the plastic film for molding is exactly the same, and further, the thermal deformation behavior due to the temperature decrease after molding is also exactly the same, so cracking and Molding defects such as peeling were less likely to occur. In particular, the defective molding was reduced and the yield was improved even in the corners of the blister pack and the contour package, which were liable to be defective in molding such as cracking and peeling.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a sectional view showing a plastic film for molding according to the present invention, FIG. 2 is an explanatory view showing its production process, and FIG. 3 is an explanatory view showing a vacuum forming process.

Molding plastic film 1 shown in FIG.
Is used for forming a packaging container such as a blister pack which is a plastic product by vacuum or pressure forming, wherein a polyester resin is used as a vehicle on at least one surface of a transparent base film 2 made of a polyester resin such as PET. Gravure ink (coating agent) 3
The color coating 4 is formed.

The composition of the gravure ink 3 of this example is PET.
A vehicle containing a water-dispersible polyester resin (film forming element), water (solvent), and alcohol (cosolvent) close to
The pigment is dispersed and an auxiliary agent is added. Since the gravure ink 3 is water-soluble and does not use an organic solvent such as ketone, ether, ester, etc., the problem of environmental pollution caused by using the ink 3 hardly occurs. Further, when imparting metallic luster or pearl luster to the color coating 4, the gravure ink 3 containing a metal filler or a pearl pigment is used. And
The color coating 4 is formed by printing the entire surface of the base film 2 with the gravure ink 3.

As shown in FIG. 2, the gravure printing is carried out by forming fine concave portions called shells having a depth of 2 to 40 μm, which are formed in a matrix at a pitch of 100 to 200 per 25.4 mm on the peripheral surface of the plate cylinder 5. Intaglio printing is performed by filling dots with gravure ink 3 and transferring the gravure ink 3 to the base film 2.

When the molding plastic film 1 is produced, as shown in FIG. 2, the base film 2 is unwound from the unwinding roller 6 and is pressed against the plate cylinder 5 by the impression cylinder 7 to form a color on one side thereof. The coating film 4 is formed, dried by the dryer 8, and then wound up by the winding roller 9.

When a blister pack is formed by vacuum forming using the plastic film 1 for molding thus formed, as shown in FIG. 3, the film 1 cut into a predetermined size is used for removing. By heating and softening by a heater 13 on a die 12 provided with a large number of small holes 11 (FIG. 3 (a)), the air between the film 1 and the die 12 is rapidly extracted by a vacuum pump or the like. , Film 1
Is adsorbed to the surface of the mold 12 by atmospheric pressure and molded into that shape (FIG. 3 (b)), and after cooling and solidification, air is sent into the mold 12 to take out the molded product 14 (FIG. 3 (c)). .

Here, when the molding plastic film 1 is heated and softened by the heater 13, both the base film 2 and the color coating 4 are made of polyester resin, so that they soften at the same temperature.

Next, when the molding plastic film 1 is molded by removing air from the mold 12, stress acts on the molding plastic film 1, but both the base film 2 and the color coating 4 are molded from polyester resin. Therefore, the deformation behavior with respect to the stress is the same, and molding defects such as cracks and peeling are unlikely to occur.

Further, when the molding plastic film 1 molded into a mold shape is cooled and solidified, thermal shrinkage occurs due to a temperature decrease, but both the base film 2 and the color coating 4 are molded with a polyester resin. Therefore, the thermal deformation behavior with respect to the stress is the same, and molding defects such as cracks and peeling are unlikely to occur.

As described above, since the base film 2 and the color coating 4 are unlikely to be cracked or peeled off due to the stress or thermal deformation acting on the molding plastic film 1 during the vacuum molding, conventionally, molding failure occurs. Molding defects were reduced and the yield was improved even in the corners of the blister pack and the contour package, which were easy to do.

In the above description, the case where a colorless and transparent polyester resin film is used as the substrate film 2 has been described, but the present invention is not limited to this, and a colored and transparent polyester resin film or a pre-colored polyester resin film is used. An opaque polyester resin film may be used. In this case, if the transparency of either the substrate film 2 or the color coating 4 is lowered, the color when viewed from the front surface and the color when viewed from the back surface can be changed.

The color coating 4 is not limited to being formed on one side of the substrate film 1, but may be formed on both sides, and is not limited to gravure printing with the gravure ink 3 and may be any printing. You may form using a means or a coating means. Further, the color coating 4 is not limited to the case where a single color ink or a single color paint is printed on the entire surface of the substrate film 2, but characters or patterns are printed using a plurality of colors of ink or paint, or a partial one-point mark is used. May be printed. When printing characters or one-point marks, the plastic film may be reduced in size by a predetermined magnification in advance in accordance with the amount of expansion of the plastic film so that it has a desired shape in the molded state, or the amount of expansion in the length and width is approximately Just print it on the same area.

Further, the plastic film 1 for molding is not limited to the case of molding a packaging container such as a blister pack.
Any plastic product produced by vacuum or pressure forming can be molded.

[0030]

As described above, according to the present invention, since the color film formed of the coating agent is formed on at least one surface of the base film, not only the small amount can be produced by printing or painting, but also Since both the base film and the color coating are made of polyester resin,
It has a very excellent effect that it is easy to be familiar with each other, and that the deformation behavior against stress and heat is the same during vacuum or pressure molding, and that molding defects such as cracks and peeling hardly occur.

[Brief description of drawings]

FIG. 1 is a sectional view showing a plastic film for molding according to the present invention.

FIG. 2 is an explanatory view showing the production process.

FIG. 3 is an explanatory view showing a vacuum forming process.

[Explanation of symbols]

1 ... Plastic film for molding 2 ... Base film 3 ... coating agent 4 ......... Color coating

Continued front page    F term (reference) 3E033 AA08 BA17 BB08 CA20 DA08                       DD01 EA10 FA04                 3E086 AC22 AC33 AD07 BA04 BA24                       BA35 BB62 BB63 BB85 CA01                       CA28 CA35 DA08                 4F100 AB01B AK41A AK41B AT00A                       BA02 BA07 CA13B CA23B                       EH46B GB16 HB00B JL01                       JL10B JN01A JN22B

Claims (5)

[Claims] 1. A plastic film or sheet for molding, which is used as a molding material for a plastic product by vacuum or pressure molding, comprising a base material film or sheet made of a polyester resin, and a coating agent having a vehicle of the polyester resin on at least one surface thereof. A plastic film or sheet for molding, which is provided with a color film. 2. The molding plastic film or sheet according to claim 1, wherein the base film or sheet is transparent. 3. The plastic film or sheet for molding according to claim 1, wherein the coating agent contains a metal filler or a pearl pigment. 4. The molding plastic film or sheet according to claim 1, wherein the color coating has characters or patterns. 5. The molding plastic or sheet according to claim 1, wherein the plastic product is a packaging container such as a blister pack.