JPH07102643B2 - Molding sheet and molded article using the sheet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sheet used for producing a molded body by vacuum forming, pressure forming, insert injection molding, etc., and a molded body made from the sheet.

[Conventional technology and its problems]

According to the above-mentioned molding methods, the raw material sheets must all have sufficient plasticity, and a metal thin film such as an aluminum foil has a problem that breakage or tears easily occur. Therefore, when the molded product by these methods is used for packaging foods, chemicals, etc., in order to impart barrier properties, a synthetic resin such as polyvinylidene chloride or polyvinyl alcohol, and other thermoplastic synthetic resin Although methods such as forming a laminated body or mixing various pigments and fillers have been adopted, none of them has provided a container having a sufficient barrier property, particularly a barrier property against light.

Further, also in the case of a sheet for molding a casing for housing electric and electronic devices having electromagnetic wave shielding properties, similarly, with a filler or the like, sufficient shielding properties cannot be obtained.

Therefore, a sheet in which a metal foil such as an aluminum foil is attached to a heat-shrinkable film at a large number of small area portions and heat-shrinked is proposed by the present inventors (Japanese Patent Application No. 60-160766). ).

However, such a sheet is strongly but partially bonded between the metal foil and the heat shrinkable film,
In addition, it is necessary to use a metal foil that is thin enough to adapt to the shrinkage of the film. Therefore, the metal foil of the non-bonded portion is weak against external force, for example, it is torn by a sharpened film at the time of heat shrinkage, or the metal foil of the cut end face is partially dropped when the sheet after shrinkage is cut and processed. There is.

[Problems of the Invention]

Therefore, an object of the present invention is to provide a molding sheet capable of forming uniform shrinkage wrinkles and a molded body formed from the sheet without causing breakage or dropping even if a thin metal thin film is used. is there.

[Means for solving problems]

In order to solve the above problems, in the present invention, the resin layer surface of the synthetic resin layer having a metal thin film, a substrate is formed by laminating a heat-shrinkable synthetic resin film through an intermittent adhesive layer, The base material is heat-shrinked to form a forming sheet having wrinkles formed on the metal thin film, or a thermoplastic synthetic resin layer is provided on at least one surface of the forming sheet to form a forming sheet.

Further, these sheets were molded to form a molded body.

[Action]

As described above, when the base material is heat-shrinked, many fine wrinkles are generated in the synthetic resin layer having the metal thin film due to the shrinkage of the heat-shrinkable synthetic resin film, and accordingly, the entire surface of this synthetic resin layer is wrinkled. Uniform wrinkles are formed on the joined metal thin film.

Even if the base material is spread by molding such a base material, since the metal thin film has wrinkles, the metal thin film absorbs the elongation and the metal thin film does not break.

〔Example〕

First, the base material before heat shrinkage will be described with reference to FIGS. 1 to 5.

As shown in FIG. 1, the base material 1 is obtained by laminating a heat-shrinkable synthetic resin film 5 on a thermoplastic synthetic resin layer 3 having a metal thin film 2 with an intermittent adhesive layer 4 interposed therebetween.

The heat-shrinkable synthetic resin film 5 is made of polyethylene,
It is preferable to use a resin made of polypropylene, vinyl chloride, polystyrene, polyester, or the like and having a shrinkage ratio as large as possible, for example, about 50%. The film 5 may be a single body or a laminate of two or more kinds of films.

The metal thin film 2 may be a metal foil such as an aluminum foil or a copper foil, or a vapor deposition film of aluminum or tin.

The thermoplastic synthetic resin layer 3 is a single substance or a laminate of polyethylene, polypropylene, vinyl chloride, polystyrene, acrylic, polyethylene terephthalate, ethylene-vinyl acetate copolymer, or the like.

The method of laminating the synthetic resin layer 3 and the metal thin film 2 may be any method such as coating, extrusion and laminating of films. When the metal thin film is a vapor deposition film, it may be simply vapor deposited on the film as the synthetic resin layer 3.

The intermittent sticking layer 4 may be formed by a means capable of sticking the synthetic resin layer 3 and the film 5 together. In addition to the adhesive, the characteristics of the film 5 are utilized to perform heat fusion or ultrasonic fusion. You may also wear it. The pattern of the adhesive layer 4 is
Any of the linear shape as shown in FIG. 2A, the dot shape as shown in FIG. 2B, the lattice shape as shown in FIG. 2C, the design pattern as shown in FIG. Need only be a pattern in which the intermittent portion 6 exists without being provided on the entire surface. Furthermore, the intermittent portion 6 may contain a resin that easily flows at the shrinking temperature of the film 5.

As shown in FIG. 3, the thermoplastic synthetic resin layer 3 may be provided on both sides of the metal thin film 2. Further, as shown in FIG. 4, the synthetic resin layers 3 may be provided on both surfaces of the metal thin film 2, and the film 5 may be laminated via the adhesive layer 4. In addition, as shown in FIG. 5, a film 5 may be laminated on the outer surface of the metal thin film 2 of the base material 1 shown in FIG. 1 via the adhesive layer 4.

When such a substrate 1 is heated, the film 5 shrinks as shown in FIG. On the other hand, since the synthetic resin layer 3 having the metal thin film 2 is bonded to the film 5 via the intermittent bonding layer 4, as the film 5 shrinks, the synthetic resin layer 3 is attracted to each of the intermittent parts 6 and becomes fine. Wrinkles occur.
Therefore, similar wrinkles also occur in the metal thin film 2 that is entirely bonded to the synthetic resin layer 3. This sheet 10 is a contracted sheet of the one shown in FIG. 4, but it is shown in FIG. 1, FIG. 3, and FIG.
The same applies to the base material 1 in the figure.

Further, the molding sheet 10 may be formed by providing the thermoplastic synthetic resin layer 8 as shown in FIGS. 7 and 8 on one side or both sides of the sheet having fine wrinkles thus formed.

In order to stack the resin layer 8, an adhesive may be used in addition to extrusion, thermocompression bonding and the like.

When the molding sheet 10 thus obtained is subjected to vacuum or pressure molding, for example, a molded body 20 as shown in FIG. 9 is obtained.
Is obtained. In the figure, 21 is a bottom wall, 22 is a rising peripheral wall continuous with the bottom wall, and 23 is a flange provided around the opening.

The shape of the molded body 20 is arbitrary. It may be circular, elliptical, polygonal, or the like. Further, the flange may be formed as needed.

Next, the case where a molded body is obtained by insert injection molding will be described.

As shown in FIG. 10, the molding sheet 10 is formed into a molding die.
Inserted between 31 and 32, after pressing both molds, molten thermoplastic synthetic resin is injected from the nozzle 33, cooled and solidified, and then taken out to obtain a molded body 30 as shown in FIG. 11. To be

In the figure, 34 is the injected synthetic resin.

〔effect〕

According to the present invention, as described above, a heat-shrinkable film is attached to a synthetic resin layer having a metal thin film, and this is heat-shrinked to form fine wrinkles in the metal thin film together with the synthetic resin layer. , Uniform wrinkles are formed on the metal thin film,
Even if the metal thin film is spread by molding, it does not break or fall off, and the wrinkles of the metal thin film absorb the elongation and no breakage occurs. Therefore, the excellent barrier property and electromagnetic wave shielding property of the metal thin film are maintained as they are. A molded product having excellent barrier properties and electromagnetic wave shielding properties can be obtained.

[Brief description of drawings]

1, 3 to 5 are cross-sectional views showing some examples of the base material used for the molding sheet of the present invention, FIG. 2 is a plan view showing a pattern of an adhesive layer, and FIG. 6 is Sectional drawing which shows the molding sheet which heat-shrinked the base material same as the above, FIG. 7, and FIG.
FIG. 9 is a sectional view showing another example of a molding sheet, FIG. 9 is a sectional view of a molded body, FIG. 10 is a sectional view showing an example of injection molding,
FIG. 11 is a cross-sectional view of the obtained molded body. 1 ... Substrate, 2 ... Metal thin film, 3 ... Thermoplastic synthetic resin layer, 4 ... Intermittent adhesive layer, 5 ... Heat shrinkable synthetic resin film, 6 ... Intermittent part, 8 ... Heat Plastic synthetic resin layer, 10 ...
… Molding sheet, 20 …… molded body, 21 …… bottom wall, 22 …… peripheral wall, 30 …… molded body.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hideyo Shigematsu 1-25-4 Minamikyutaro-cho, Higashi-ku, Osaka City, Osaka Prefecture Toyo Aluminum Co., Ltd. (56) References: 61-18833 (JP, U)

Claims (4)

[Claims] 1. A base material in which a heat-shrinkable synthetic resin film is laminated on the resin layer surface of a synthetic resin layer having a metal thin film via an intermittent adhesive layer by heat shrinking to form wrinkles in the metal thin film. Molded sheet. 2. A heat-shrinkable synthetic resin film is laminated on the resin layer surface of a synthetic resin layer having a metal thin film via an intermittent adhesive layer, and the film is heat-shrinked to form wrinkles on the metal thin film. A molding sheet in which a thermoplastic synthetic resin layer is provided on at least one surface of a base material. 3. A heat-shrinkable synthetic resin film is laminated on the resin layer surface of a synthetic resin layer having a metal thin film via an intermittent adhesive layer, and the film is heat-shrinked to form wrinkles on the metal thin film. A molded body formed by molding a sheet. 4. A heat-shrinkable synthetic resin film is laminated on the resin layer surface of a synthetic resin layer having a metal thin film via an intermittent adhesive layer, and the film is heat-shrinked to form wrinkles on the metal thin film. A molded product obtained by molding a sheet in which a thermoplastic synthetic resin layer is provided on at least one surface of a base material.