JPH0564863A - Laminated sheet having heat moldability and barrier properties - Google Patents

Abstract

PURPOSE:To obtain heat moldability equal to or more than that of a sheet using a vinyl chloride resin sheet and a vinylidene chloride copolymer by employing a laminated sheet formed by laminating a non-stretched polypropylene sheet to an amorphous polyester sheet. CONSTITUTION:A polyester adhesive is applied to the single surface of an amorphous polyester sheet 2 by a gravure coating method and, after the drying of the adhesive layer, a non-stretched polypropylene sheet 1 is bonded and laminated to the polyester sheet 2 by a dry lamination method under pressure to obtain a laminated sheet. By this constitution, since this laminated sheet contains no chlorine different from a sheet using a vinyl chloride resin sheet and a vinylidene chloride copolymer, the bad effect based on chlorine is not generated in the disposal treatment of the laminated sheet and environmental pollution due to waste can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to, for example, PTP for pharmaceuticals.
The present invention relates to a laminated sheet having thermoformability and barrier properties, which is used for packaging and the like.

[0002]

2. Description of the Related Art Conventionally, as a laminated sheet having thermoformability and barrier properties, a vinylidene chloride copolymer copolymer having a vinylidene chloride copolymerization ratio of 80 to 95% by weight is provided on one surface of two thermoformable resin sheets. Combined emulsion with solid content of 3 ~
A laminated sheet is known in which 70 g / m ² is applied, and molten polyethylene is extruded between the applied surfaces so that the thickness is 20 to 70 μm and fixed so that the total thickness is 150 to 2000 μm ( Japanese Examined Japanese Patent Publication Sho 49-245
87).

The above-mentioned conventional laminated sheet having thermoformability and barrier properties has a required barrier property by a vinylidene chloride copolymer, and the vinylidene chloride copolymer has poor thermoformability. The thermoformable resin sheet as described above is supplemented by supporting a vinylidene chloride-based copolymer to obtain good thermoformability as a whole.

In Japanese Patent Publication No. 49-24587 mentioned above, as thermoformable resin sheets, vinyl chloride resin sheets, polystyrene sheets, unstretched polypropylene sheets, cellulose acetate sheets, polycarbonate sheets, unstretched high density polyethylene sheets are disclosed. Among these, vinyl chloride resin sheets are excellent in economic efficiency and thermoformability, and therefore, in the actual market, those using hard vinyl chloride resin sheets are predominant.

[0005]

However, since a laminated sheet obtained by laminating a vinylidene chloride copolymer on a hard vinyl chloride resin sheet contains a large amount of chlorine, there is a problem in waste disposal.

That is, if it is buried in soil, it may decompose in a long period of time to produce a chlorine-based harmful substance (eg, dichloroethylene suspected of being carcinogenic), and when incinerated, chlorine gas is generated. This not only damages the living environment, but also causes the depletion of the ozone layer surrounding the earth.

Therefore, it is desired to form a laminated sheet without using the hard vinyl chloride resin sheet and the vinylidene chloride copolymer which cause such a problem.
Further, a laminated sheet obtained by laminating a vinylidene chloride-based copolymer using a hard vinyl chloride resin sheet as a base material has a high moldability, but if a laminated sheet having further excellent moldability is obtained, it is extremely useful in industry. There is no doubt. That is, when the laminated sheet is thermoformed and subjected to PTP packaging or the like, if it can be thermoformed at a lower temperature, the molding cycle can be shortened and the production efficiency can be improved. Therefore, good thermoformability at a lower temperature is desired.

The above-mentioned demand is solved by laminating a resin sheet having excellent barrier properties and containing no chlorine on a resin sheet which has good moldability at a lower temperature than a hard vinyl chloride resin sheet and which does not contain chlorine. Think of it as possible. However, even if the substrate is excellent in low temperature thermoformability, the barrier resin to be laminated is not always formed in the same manner, and depending on the combination of the two, the barrier property and the formability are adversely affected. It might fit.

The present invention has been made in view of the problems of a chlorine-containing laminated sheet, and is a chlorine-free resin that does not cause a problem at the time of waste treatment, and does not significantly impair the barrier property. It is an object of the present invention to obtain a thermoformability equal to or higher than that of a laminated sheet using a vinylidene chloride copolymer as a vinyl resin.

[0010]

Means and Actions for Solving the Problems To explain the measures taken in the present invention for solving the above problems, in the present invention, a laminate in which an unstretched polypropylene sheet 1 is laminated on an amorphous polyester sheet 2 is laminated. It takes measures to make it a sheet (see FIG. 1). The unstretched polypropylene sheet 1 may be laminated on only one side of the amorphous polyester sheet 2 or may be laminated on both sides.

In the laminated sheet according to the present invention, two sheets of the non-stretched polypropylene sheet 1 are laminated on one side of the amorphous polyester sheet 2, and the laminated side of the non-stretched polypropylene sheet 1 is faced to form polyethylene. It is preferable to use it as a laminated sheet (see FIG. 2) that is fixed through the barrier sheet because the barrier property is easily improved and the bending strength is also improved.

The present invention will be further described.

First, the amorphous polyester used as the base sheet in the present invention brings good moldability to the present laminated sheet. For example, the crystallinity of polyester (hereinafter referred to as "PET") is controlled by polymer modification. Can be obtained by It is currently obtained by substituting a part of the glycol component with 1,4-cyclohexanedimethanol to control the crystallization rate of PET.

Amorphous PET has good thermoformability because it is amorphous, and has a low glass transition point of about 81 ° C., so that it can be thermoformed at a relatively low temperature. Further, the reason why the amorphous PET sheet 2 is used as a substrate in the present invention is not only that the thermoformability is good, but that the excellent properties of the unstretched polypropylene sheet 1 laminated on the amorphous PET sheet 2 are not impaired. This is because excellent moldability is exhibited.

In the present invention, the above-mentioned amorphous PET sheet 2 is used as a base material, and the thickness thereof is 150 to 350 μm both when the unstretched polypropylene sheet 1 is laminated on one side and when it is laminated on both sides. Is preferred. If the thickness of the amorphous PET sheet 2 is too small, it is difficult to obtain the required formability, and conversely, if the thickness is excessively increased, the formability is not further improved and the waste becomes large. In addition, the thickness of the amorphous PET sheet 2 when the laminated sheet of the present invention is in the laminated state of FIG. 2 is preferably 150 to 350 μm for the same reason as above.

The unstretched polypropylene sheet 1 to be laminated on the amorphous PET sheet 2 provides barrier properties to the present laminated sheet, and can be laminated by a dry laminating method using an adhesive. As the adhesive used for this lamination, for example, a polyester adhesive can be used. When laminating, an anchor coat may be applied to the laminating surface.

The thickness of the unstretched polypropylene sheet 1 is
In the case of a one-sided layer, it is preferably 20 to 100 μm. If the thickness of the unstretched polypropylene sheet 1 is too small, it is difficult to obtain sufficient barrier properties, and if it is too large, the unstretched polypropylene sheet 1 is easily damaged during molding. When the unstretched polypropylene sheet 1 is laminated on both sides of the amorphous PET sheet 2 and when the laminated sheet of FIG. 2 is used, each unstretched polypropylene sheet 1 has a thickness of 10 to 100 μm for the same reason as above. Preferably. In this case, since the thickness of the unstretched polypropylene sheet 1 can be doubled as compared with the case of laminating only one side,
The barrier property can be improved.

In order to bring the laminated sheet of the present invention into the laminated state shown in FIG. 2, one surface of each of the two amorphous PET sheets 2 is
This can be carried out by applying an anchor coat as needed, laminating the unstretched polypropylene sheet 1 and then fixing the surface of the unstretched polypropylene sheet 1 with polyethylene 3.

Fixing with the polyethylene 3 can be easily performed by a polyethylene extrusion laminating method. That is, two amorphous PET sheets 2 each having a non-stretched polypropylene sheet 1 laminated on one side thereof are drawn out with their non-stretched polypropylene sheet 1 sides facing each other, and molten polyethylene is extruded from a T-die between them for lamination. You can

The polyethylene 3 has a thickness of 15 to 70.
μm is preferable, and more preferably 30 to 50.
μm. If the thickness of the polyethylene 3 is too small, it is difficult to obtain sufficient adhesive strength, and if it is too thick, the amorphous PET sheet 2 is likely to be thermally deformed during lamination.

At the time of this lamination, the surface of the non-stretched polypropylene sheet 1 to be the adhesive surface may be subjected to anchor coat treatment, if necessary. As the anchor coating agent, for example, an alkyl titanate-based, polyisocyanate-based, or polyalkyleneimine-based anchor coating agent such as polyethyleneimine can be used.

In particular, the laminated sheet shown in FIG. 2 laminated by using the polyethylene 3 has not only improved barrier properties as described above but also becomes a laminated sheet excellent in bending strength due to the buffering action of the polyethylene 3. ..

In the laminated film of the present invention, in the case of a single-area layer, the total thickness is preferably 170 to 450 μm, and in the case of double-sided lamination, the total thickness is 200 to 550.
It is preferably μm. When the laminated sheet of the present invention is used in the laminated state shown in FIG. 2, the total thickness of the laminated sheet shown in FIG. 2 is preferably 350 to 800 μm. If the total thickness is too small, it is difficult to obtain the thickness of the amorphous PET sheet 2 and the thickness of the polyethylene 3 necessary for maintaining the moldability and the adhesive strength, and if the total thickness is too large, the amorphous PET sheet 2 and The thickness of the polyethylene 3 becomes unnecessarily large and waste becomes large.

[0024]

【Example】

Example 1 As the amorphous PET sheet, “PETG sheet” (240 μm thick) manufactured by Eastman Kodak Co., Ltd. was used, and on one side thereof, a polyester adhesive (AD-577-1 (CAT manufactured by Toyo Morton Co., Ltd.) by a gravure coating method was used. -10) to 3
After applying 3.5 g / m ² (solid content) and drying, an unstretched polypropylene sheet having a thickness of 50 μm (SC type manufactured by Tohcello Chemical Co., Ltd.) was pressure-bonded and laminated by a dry lamination method to give an overall thickness of 2
A 90 μm laminated sheet was obtained.

The water vapor transmission rate of the above laminated sheet was measured and found to be about 0.27 g / m ² · 24 h.
The water vapor transmission rate was measured according to JIS.

The above laminated sheet was evaluated for formability by hot plate heating under pressure / vacuum forming.

Molding was carried out so as to mold a round container having a diameter of 92 mm, a depth of 23 mm (molding draw ratio of 0.25), and a rounded container having a radius of about 2 mm around the bottom. Molding was performed while increasing the temperature of the hot plate at intervals of 10 ° C., and the radius of the roundness formed around the bottom of the obtained molded product was measured.

The results are shown in FIG. The mold reproducibility was determined to be good when the measured radius of roundness around the bottom of the molded product was in the range of 1.5 to 3 mm.

The thickness of each part of the obtained molded product having a roundness of 2 mm was measured,
The change state of the thickness was examined.

The results are shown in FIG.

Comparative Example 1 A roundness radius was obtained in the same manner as in Example 1 except that the amorphous PET sheet was changed to a vinyl chloride resin sheet having a thickness of 230 μm and a vinylidene chloride copolymer was laminated to a thickness of 25 μm on the vinyl chloride resin sheet. And thickness were measured.

The results are shown in FIGS. 3 and 4.

Example 2 A 100 μm-thick unstretched polypropylene sheet was laminated on each side of an amorphous PET sheet to form a total thickness of 440 μm.
A laminated sheet was produced in the same manner as in Example 1 except that.

A rounded sheet was obtained in the same manner as in Example 1 except that the above laminated sheet was formed into a container having a diameter of 37 mm, a circular shape, and a depth of 18.5 (molding draw ratio of 0.5). The measurement was performed.

The results are shown in FIG.

Further, among the obtained molded products, the thickness of each part of the molded product was measured for the roundness radius of 1.5 mm, and the change state of the thickness was examined.

The results are shown in FIG.

Comparative Example 2 A roundish radius was obtained in the same manner as in Example 2 except that the amorphous PET sheet was changed to a vinyl chloride resin sheet having a thickness of 230 μm and a vinylidene chloride copolymer was laminated to a thickness of 25 μm on the vinyl chloride resin sheet. And thickness were measured.

The results are shown in FIGS. 5 and 6.

[0040]

The present invention is as described above and has the following effects. (1) It uses an amorphous PET sheet and a non-stretched polypropylene sheet, and does not contain chlorine like those using a vinyl chloride resin sheet and a vinylidene chloride-based copolymer. It is possible to prevent waste pollution without causing (2) It is possible to obtain thermoformability equal to or higher than that when a vinyl chloride resin sheet and a vinylidene chloride copolymer are used. (3) Since the molding temperature is low, it is possible to enhance the molding cycle and improve the productivity of molded products.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a laminated sheet according to the present invention.

FIG. 2 is a cross-sectional view of a laminated sheet in which the laminated sheet of the present invention is further laminated.

FIG. 3 is a graph showing the results of Example 1 and Comparative Example 1.

FIG. 4 is a graph showing the results of Example 1 and Comparative Example 1.

FIG. 5 is a graph showing the results of Example 2 and Comparative Example 2.

FIG. 6 is a graph showing the results of Example 2 and Comparative Example 2.

[Explanation of symbols]

 1 Unstretched polypropylene sheet 2 Amorphous polyester sheet 3 Polyethylene

Claims (1)

[Claims] 1. A laminated sheet having thermoformability and barrier properties, which is obtained by laminating an unstretched polypropylene sheet on an amorphous polyester sheet.