JP3091298B2 - Heat-sealing lid material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat-sealing lid material for packaging,
PTP packaging (Press Th
The present invention relates to a heat-sealing lid material for rough packs.

[0002]

2. Description of the Related Art A PTP wrapping material is a processed part of a plastic sheet formed with a pocket, which is a part of a container for storing contents, and a part of a lid for sealing a container mouth. It is composed of two parts: a cover member provided with a heat-sealing resin layer on one surface of a base material such as a metal foil, a plastic sheet or paper.

As the plastic sheet forming the container body, a vinyl chloride resin sheet has been used for a long time because of its excellent workability. In recent years, however, a polypropylene sheet has been used because of its excellent moisture-proof property and its low cost. Is being used. On the other hand, aluminum foil is usually used as the base material of the lid material, but a paper base material such as glassine paper may be used because it has a specific effect or is inexpensive. In addition,
A plastic film processed to facilitate rupture has also been proposed, but has not yet been put to practical use.

[0004] The above-mentioned cover material usually has characters or designs printed on one or both sides of a base material such as aluminum foil or glassine paper, and one side (the outside side) is further printed thereon.
If necessary, apply a colorless or colored transparent heat-resistant coating agent or laminate a plastic film to provide a heat-resistant resin layer to protect printed layers such as characters and designs during heat sealing. The surface (the surface to be adhered) is manufactured by applying a colorless or colored heat-sealing coating agent to form a heat-sealing resin layer in order to heat-seal the plastic container by heat and pressure. .

[0005] In the packing operation, the contents are filled in a processed article of a polyvinyl chloride resin sheet or a polypropylene sheet provided with a pocket serving as the container, and then the aluminum is placed on the opening side thereof. A lid material having a base material such as foil or glassine paper is laminated so that the heat-sealing resin layer is in contact with the heat-sealing resin layer. This is accomplished by applying heat and pressure to heat seal the non-pocketed portion of the plastic container.

The heating and pressing conditions vary depending on the type of the laminated material, but the heat sealing temperature is set between 80 and 250 ° C., and the heat sealing pressure is often set at 1 to 3 kgf / cm ^2. .

The heat-sealable resin layer of the lid material is usually made of a thermoplastic resin, and depending on the material of the plastic container, a vinyl chloride (co) polymer, an ethylene-vinyl acetate copolymer, a chlorinated polypropylene or the like is used. Although a resin composition containing a resin as a main component is used, chlorinated polypropylene has conventionally been used for a polypropylene container.

When chlorinated polypropylene is used as the heat-sealing resin, the heat-sealing property between the aluminum foil and the molded product of the polypropylene sheet is good, but chlorine is easily released. Disadvantageously, or the quality of contents such as stored medicines is impaired. As a solution, acid-modified polypropylene or a resin composition containing acid-modified polypropylene as a main component has recently been used as a heat-sealing resin. When such an acid-modified polypropylene is used, the heat sealing property between the aluminum foil and the processed molded article of the polypropylene sheet is good, and there is no problem such as generation of chlorine.

[0009]

However, when acid-modified polypropylene is used for the heat-sealing resin layer,
Usually, the adhesion between the printing layer of the gravure ink containing the acid-modified vinyl chloride-vinyl acetate copolymer, which is widely used for printing aluminum foil, as the main component of the vehicle and the heat-sealing resin layer is improved. Not enough. For this reason, when airtight leakage occurs from the printed portion of the lid material of the PTP package, or when the entire surface is printed for coloring the entire surface of the aluminum foil, etc., between the printed layer and the heat-sealing resin layer, There is a problem of easy peeling.

In order to improve the adhesiveness, various studies have been made on heat-sealing resins, but a resin having satisfactory performance has not yet been obtained. On the other hand, attempts have been made to improve the adhesion by changing the vehicle component of the gravure ink, that is, the resin component of the printing layer.
For example, by using a resin composition in which a thermoplastic resin such as a polyester resin is blended with a vinyl chloride-vinyl acetate copolymer as a resin component of the printing layer, the adhesion between the printing layer and the heat-sealing resin layer is improved. Proposal (for example,
-8036). This has a considerable improvement effect, but it is still not enough.

[0011]

Means for Solving the Problems The present inventor has proposed that a resin having a functional group which can react with an acid group of an acid-modified polypropylene is added to a resin component of the printing layer, thereby making the printing layer heat-sensitive. As a result of intensive studies on the assumption that the adhesion to the sealing resin layer can be further improved, the present invention was completed. That is, the present invention relates to a heat-sealing lid material for a polypropylene resin container comprising a printing layer and a heat-sealing resin layer mainly containing an acid-modified polypropylene on an aluminum foil in this order. The components, i.e., the vehicle of the gravure ink used to print the printing layer is mainly composed of an acid-modified vinyl chloride-vinyl acetate copolymer and a thermosetting acrylic resin, and the resin component of the heat-sealing resin layer is acid-modified. It is characterized by containing polypropylene as a main component. Such a heat-sealing lid material,
The heat sealing property with the processed molded article of the polypropylene sheet is good, no harmful gas such as chlorine is generated, and the adhesion between the printing layer and the heat sealing resin layer is good.

The aluminum foil used in the present invention includes:
Any hard or soft aluminum foil commonly used for packaging materials can be used. For PTP packaging, 10 to 40 μm for soft foil and 5 for hard foil.
~ 30 μm, but depending on the application and purpose, 10 μm
It may be 0 μm or more. Also, if laminated and reinforced with a film of a synthetic resin or the like, an aluminum foil of about 3 μm can be used.

The printing layer of the heat-sealing lid material of the present invention is usually
It is formed by printing using gravure ink and consists of pigment and vehicle solids. The thickness of the printing layer is not particularly limited, and an appropriate thickness can be adopted according to various conditions such as the purpose of printing, the type of printing machine, and the ink density. The vehicle solid content is a resin component mainly composed of an acid-modified vinyl chloride-vinyl acetate copolymer and a thermosetting acrylic resin.

The mixing ratio of the acid-modified vinyl chloride-vinyl acetate copolymer and the thermosetting acrylic resin in the resin component of the printing layer is as follows:
90 to 40% by weight and 10 to 60% by weight of a thermosetting acrylic resin are preferred. When the compounding ratio of the thermosetting acrylic resin is less than 10% by weight, the effect of improving the adhesiveness with the heat-sealing resin layer does not appear, and when it exceeds 60% by weight, the adhesiveness with the aluminum foil decreases.

The type of the acid-modified vinyl chloride-vinyl acetate copolymer, which is the first component of the resin component of the printing layer, is not particularly limited, but the physical properties of the printing layer and the workability of production and coating are not limited. Considering the vinyl chloride content is 95-50
% By weight, content of vinyl acetate is 5 to 50% by weight, content of polymerizable carboxylic acid such as (meth) acrylic acid and maleic acid, content of polybasic inorganic acid such as phosphoric acid is 0.1 to 5% by weight, degree of polymerization Is preferably about 300 to 1,000. A copolymer obtained by hydrolyzing a vinyl acetate group in the copolymer to be modified into a hydroxyl group may be used as a main component. Examples of the copolymer include, for example, an acid-modified vinyl chloride-vinyl acetate copolymer used in the field of commercial paints and adhesives. Specific examples of the monomer having a copolymerizability with the vinyl chloride, vinyl acetate and polymerizable carboxylic acid include, for example, hydroxyethyl or hydroxypropyl (meth) acrylate having a hydroxyl group, and glycidyl (meth) acrylate having an epoxy group. Functional monomers and olefins such as ethylene and (meth) acrylic acid esters, etc.
It is not limited to these.

The thermosetting acrylic resin, which is the second component of the resin component of the printing layer, includes a hydroxyalkyl group, a glycidyl group, an aminoalkyl group or the like as a pendant group, an amino resin, a polycarboxylic acid, a polyvalent carboxylic acid, It is generally marketed as a thermosetting acrylic resin for paint, such as a type using an ethyleneimine compound, a polyepoxide, a polyisocyanate as a crosslinking agent, or a so-called self-crosslinking type using an alkyletherified methylol group as a pendant group. Although a self-crosslinking type having an alkyletherified methylol group as a pendant group is used, the adhesion between the printing layer and the heat-sealing resin layer is large, and it is obtained stably. preferable. The term “main component” means that the present invention includes a case where a resin-based additive is contained in the resin component of the printing layer in addition to the vinyl chloride-acetic acid copolymer and the thermosetting acrylic resin. Examples of such additives include additives for ordinary inks, such as wetting agents, dispersants, plasticizers, leveling agents, lubricants, antioxidants, and other various resin-based additives depending on the use of packaging. Is raised.

The heat-sealing resin layer used in the present invention is a layer whose resin component is mainly composed of acid-modified polypropylene. The acid-modified polypropylene is an acid-modified polypropylene obtained by grafting an unsaturated dicarboxylic acid or the like to polypropylene, and is generally commercially available in a form of being dispersed in a medium such as an organic solvent to a concentration of 10 to 50% by weight. A product obtained by adding maleic acid to polypropylene that has been used can be suitably used. Specific examples of the commercially available acid-modified polypropylene, for example, Mitsui Petrochemical Industry Co., Ltd.
Unistor R100, R200, R300 manufactured by Toyo Ink Mfg. Co., Ltd.
000 and the like.

The heat-sealing lid material of the present invention is an ink which becomes a printing layer on aluminum foil, that is, the above-mentioned acid-modified vinyl chloride-
Using a resin component mainly composed of a vinyl acetate copolymer and a thermosetting acrylic resin as a vehicle solid content, using a pigment, a coloring agent such as a dye and a solvent and, if necessary, an ink prepared by adding the above-described additives, After printing or solid printing of characters and graphics once or many times, drying is performed under appropriate conditions, and on a printing layer formed, a resin component containing acid-modified polypropylene as a main component, and other components if necessary. After applying in the form of a dispersion or the like in which the components are added and dispersed in an organic solvent or the like,
It can be produced by drying under appropriate conditions.

The heat-sealing lid material of the present invention thus produced is laminated with a processed molded article of a polypropylene sheet, and thermally fused under the same conditions as in the prior art to obtain a PT.
Used as P packaging material.

[0020]

Next, the heat-sealing lid material of the present invention will be described with reference to Examples and Comparative Examples. Example 1 (Production of Gravure Ink for Forming Printed Layer) Table 1
Based on the formulation described in Example 1, column 1, two kinds of vinyl chloride-vinyl acetate copolymer (acid-modified vinyl chloride-vinyl acetate copolymer and ordinary vinyl chloride-vinyl acetate copolymer) were dissolved in toluene as a solvent. After the whole amount was combined and stirred to be dispersed in a suspension, the remaining solvent, methyl ethyl ketone, was added and dissolved by heating. after that,
A vehicle was prepared by adding and mixing a thermosetting acrylic resin. To the obtained vehicle, the pigment Fastogen Blue GNPT was added, mixed and wetted, and then the volume was 500 cc.
20 at 1700 rpm using a batch-type tabletop sand mill
The mixture was dispersed for about 30 minutes to produce a gravure ink.

(Manufacture of heat-sealing lid material) A character and a design are printed in advance on the matte side of a semi-rigid single-gloss aluminum foil having a thickness of 20 μm. 125 lines, cell depth 40μ
Using a gravure printing method, the entire surface was solid-printed, heated and dried to form a print layer. Further, a heat-sealing coating agent of a toluene dispersion of acid-modified polypropylene (Unistol R300 manufactured by Mitsui Petrochemical Industry Co., Ltd .: solid content 15% by weight) was similarly applied onto the formed printing layer by a gravure printing method. Thus, a heat-sealing resin layer was provided by coating so as to have a dry film thickness of 6 μm to prepare a heat-sealing lid material for a PTP packaging material.

(Adhesion Test of Heat-Sealable Lid) The following test was performed to evaluate the adhesion between the printed layer and the heat-sealable resin layer of the obtained heat-sealable lid. That is, a polypropylene sheet (NS-2400, 275, manufactured by Sumitomo Bakelite Co., Ltd.) was applied to the heat-sealing resin layer of the heat-sealing lid material at a compression temperature of 1 mm.
Heat sealed under the conditions of 80 ° C, pressure 2kg / cm ² , crimping time 0.2 seconds, hold aluminum foil and polypropylene sheet and peel at 200mm / min peel angle 180 ° The strength was measured. As a result, as shown in Table 1, a sufficient value of the heat sealing strength of 1600 g./15 mm was obtained, and the peeled surface was the interface between the printed layer and the aluminum foil.

[Table 1]

Notes 1. The numbers in the tables showing the composition are parts by weight. Note 2. The figures in parentheses in the column of resin raw materials are the values converted to the solid content weight. ‡ 1 Made by Denki Kagaku Kogyo Co., Ltd .: Electrified vinyl 1000C
(Vinyl chloride / vinyl acetate / maleic acid = 86/13/1, mol
%) ‡ 1 'manufactured by Denki Kagaku Kogyo Co., Ltd .: Electrified vinyl 1000L-
CH (vinyl chloride / vinyl acetate = 85/15, mol%) ‡ 2 Toyobo Co., Ltd .: Byron 300 (linear saturated polyester resin) ‡ 3 Nippon Polyurethane Industry Co., Ltd .: Nipporan 230
4 (one-pack type polyurethane resin, nonvolatile content 35%) ‡ 4 Mitsubishi Rayon Co., Ltd .: Dianal SE5377
(Self-crosslinking thermosetting acrylic resin, non-volatile content 50%) ‡ 5 Blue pigment manufactured by Dainippon Ink and Chemicals, Inc. ‡ 6. Mitsui Petrochemical Industries, Ltd .: Unistor R300
(Carboxylic acid-modified polypropylene, nonvolatile content 18%)

Comparative Example 1 Based on the composition described in Comparative Example 1 in Table 1, a thermoplastic polyester resin was added to an acid-modified vinyl chloride-vinyl acetate copolymer and mixed to obtain a vehicle solid content. In the same manner as in Example 1, a gravure ink was produced, and a heat-sealing lid material was further produced. Example 1 was used to evaluate the adhesion between the printed layer and the heat-sealing resin layer of the obtained heat-sealing lid material.
An adhesion test was performed in the same manner as described above. As a result, as shown in Table 1, the heat sealing strength was 500 g./15 mm, and the peeled surface was the interface between the printing layer and the heat sealing resin layer.

Comparative Example 2 Based on the formulation described in the column of Comparative Example 2 in Table 1, Example 1
A gravure ink was produced in exactly the same manner as in Example 1 except that all the two kinds of vinyl chloride-vinyl acetate copolymers used in the above were replaced with ones which were not acid-modified, and a heat-sealing lid material was produced. An adhesion test was performed in the same manner as in Example 1 to evaluate the adhesion between the printed layer and the heat-sealing resin layer of the obtained heat-sealing lid material. As a result, as shown in Table 1, the heat sealing strength was 320 g./15 mm and almost no adhesion was observed, and the peeled surface was the interface between the printed layer and the aluminum foil.

Comparative Example 3 Based on the formulation described in Comparative Example 3 in Table 1, a polyurethane resin was added to an acid-modified vinyl chloride-vinyl acetate copolymer and mixed to give a vehicle solid content. A gravure ink was produced in the same manner, and a heat-sealing lid material was further produced. An adhesion test was performed in the same manner as in Example 1 to evaluate the adhesion between the printed layer and the heat-sealing resin layer of the obtained heat-sealing lid material. As a result, as shown in Table 1, the heat sealing strength showed a slightly high value of 800 g./15 mm, but sufficient strength was not obtained, and the peeled surface was an interface between the printing layer and the heat sealing resin layer. Was.

[0027]

As described above, by using the heat-sealing lid of the present invention, the heat-sealing properties of the heat-sealing lid of the aluminum foil base material and the processed molded article of the polypropylene sheet are good. No harmful gas is generated, and the adhesion between the printing layer and the heat-sealing resin layer can be improved.

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B32B 15/08 B32B 7/12 B65D 75/34 B65D 83/04

Claims (1)

(57) [Claims] 1. A heat-sealing lid material for a polypropylene resin container comprising a printing layer and a heat-sealing resin layer provided on an aluminum foil in this order, wherein the resin component of the printing layer is acid-modified vinyl chloride-acetic acid. A heat-sealing lid material comprising a vinyl copolymer and a thermosetting acrylic resin as main components, and a resin component of a heat-sealing resin layer mainly containing an acid-modified polypropylene.