JPH11254628A - Deep-drawn container bottom material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deep-drawn container bottom material wherein, in a deep-drawn container for ham, sausage, etc., a good print registering accuracy can be obtained in addition to a sufficient deep drawing characteristics in a vacuum, air-pressure forming. SOLUTION: The deep-drawn container bottom material is a laminated material including an outermost layer on one side thereof comprising a modified polyester resin film 8 which has a printed layer 9 on its inner surface on the side of the laminated material and has a melting point in the range of 180-230 deg.C and a printing-pitch dimensional stability, the outermost layer comprising a sealant layer 13 on the other side thereof, and an intermediate layer interposed between both the outermost layers. The intermediate layer comprises at least an oxygen barrier layer 11 and/or a layer which gives a pinhole resistance and strength, and the intermediate layer satisfies, at the same time, a deep drawing characteristics due to the printing pitch dimensional stability and vacuum, air-pressure forming.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can be used for packaging thin products and members in addition to sliced ham and sausage potion packs.

[0002]

2. Description of the Related Art Conventionally, laminated film packaging materials for deep drawing containers in the above-mentioned field are printed on a cover material as a backing sheet, and the bottom material to be formed and filled is often plain.
In the case where letters or patterns were required on the bottom material side, labeling was sufficient in many cases. Deep drawing molding, filling of the bottom material, and sealing with the lid material are performed by a deep drawing filling and sealing machine (hereinafter form /
Fill-seal machine), which can be performed in-line, but there is no printing on the bottom material so far, so there is no need to consider printing registration for the bottom material, and a form-fill-seal without tension control mechanism A machine was used, and it was only necessary to feed the bottom material intermittently in the flow direction by a certain pitch length. In addition, as a bottom material for deep drawing, a laminated film having good vacuum air pressure formability made of unstretched polypropylene, unstretched nylon or the like has been used.
In addition, the lid material has a printing pitch dimensional stability made of stretched polypropylene, cellophane or polyethylene terephthalate, etc., and a rigid laminate material having a large flexural modulus is used, and the lid material is not related to molding. No problem has occurred.

[0003]

Recently, when printing is required on the bottom material side, which is the front of the product at the store, printing registration of the bottom material and the lid material, printing and forming of the bottom material are required. Type,
The registration between the printing of the bottom material and the heat seal type has become a problem. Therefore, when trying to solve such a registration problem by using a conventional form-fill-seal machine as it is, it is an absolute condition that at least the printing pitch dimensional accuracy of at least the characters and designs of the bottom material is secured. come. However, in the case of a laminated material using a non-stretched polypropylene film having good moldability as described above as a printing substrate, the printing pitch dimensional stability is poor, and good printing pitch dimensional accuracy of the bottom material cannot be obtained. Therefore, if a polyethylene terephthalate film of 16 μm or more having good printing pitch dimensional stability is adopted as a printing substrate, the registration problem can be solved, but the moldability deteriorates, and only shallow drawing can be performed.
m has a trade-off problem that it is difficult to obtain a deep drawn molded product exceeding m. Therefore, the present invention relates to a conventional foam
It is an object of the present invention to provide a bottom material that can be deep-drawn using a fill-sealing machine and that has good registration accuracy of the above-described portions of the deep-drawn container.

[0004]

In order to solve the above-mentioned problems, a deep-drawing container bottom material of the present invention has a printing layer on the inner surface on the lamination side, a melting point in the range of 180 to 230 ° C., and a printing pitch. One outermost layer made of a modified polyester resin film layer having dimensional stability, the other outermost layer made of a sealant layer, and a laminated material including an intermediate layer interposed between the outermost layers. The intermediate layer comprises at least an oxygen barrier layer and / or a layer imparting pinhole resistance and strength, and simultaneously satisfies the dimensional stability of printing pitch and the deep drawability by vacuum / pressure forming. And

The modified polyester resin film includes:
Melting point is in the range of 180 to 230 ° C., and the one having stable printing pitch dimension is used to form a laminated bottom material,
Simultaneously satisfies the printing pitch dimensional stability and the deep drawability by vacuum pressure forming.

According to the present invention, the printing pitch dimensional accuracy of the bottom material falls within the target accuracy of ± 0.1%. As a result, troubles due to poor registration accuracy of each part at the time of molding, filling and sealing are eliminated. Thus, a good deep-drawing molded product having the register of each part was obtained. On the other hand, deep drawing formability has also been greatly improved, and under the same molding conditions as before, not only was it possible to easily clear the target value of 15 mm depth at the molding center, but it was also molded into a shape close to the mold cavity Was done.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the drawings. The appearance of the deep-drawn container according to the invention is shown in FIG.
As shown in the figure, a molding part 5 for filling the contents is provided at the center part, and the lid material 1 and the bottom material 2 are heat-sealed in the peripheral hatched part 3, and a punch hole 6 for hanger display is provided at the upper part.
have.

FIG. 1b) is a sectional view taken along the line AA 'in FIG. 1a), and a dotted line 7 indicates a state where deep drawing of the bottom material is not sufficient.

The gist of the present invention is to obtain a laminated material for a bottom material which simultaneously satisfies the printing pitch dimensional stability and the deep drawing formability. The laminated structure and the material of the deep drawn container bottom material according to the present invention will be sequentially described below. explain. As shown in FIG.
The lamination structure is as follows: modified polyester resin layer 8 / print layer 9 / adhesive layer 10 / oxygen barrier layer 11 / strength layer 1
2 / The sealant layer 13 is formed. Note that the order of the oxygen barrier layer and the strength layer may be reversed.

In the laminating method, the modified polyester resin film is back-printed, while an oxygen barrier layer, a strength layer, and a sealant layer are laminated by a co-extrusion method to form a three-layer laminate. Dry lamination with the printed surface of the modified polyester resin film is performed on the oxygen barrier layer side of the laminate. In the three-layer coextrusion, the oxygen barrier layer may be used as an intermediate layer.

Although an attempt has been made to use a polyethylene terephthalate film having good dimensional stability as a printing substrate for the outermost layer, the melting point is particularly high at 250 to 265 ° C. among general-purpose plastics. Compressed air formability was impaired. Therefore, instead of polyethylene terephthalate, a modified polyester resin which is a copolymer of terephthalic acid and isophthalic acid and ethylene glycol having a melting point of 40 to 50 ° C. is used as the printing substrate.

The ink layer is provided by gravure printing on the back surface of the modified polyester resin printing base material. The ink layer is made of polyamide or acrylic resin in consideration of adhesiveness to the printing base material and post-process, that is, suitability for dry lamination. The most suitable one is selected from polyurethane, polyurethane and the like.

The adhesive layer is for bonding the printed surface of the printed modified polyester resin film to the oxygen barrier layer surface of a three-layer film comprising an oxygen barrier layer, a strength layer, and a sealant layer separately prepared. A two-component reactive adhesive is used. That is, isocyanates such as propylene toluylene diisocyanate and propylene hexamethylene diisocyanate are used as curing agents for main components such as polyesters, partially urethane-modified polyesters, polyethers, and modified ether-type polyesters. Are mixed and used.

The oxygen barrier layer is indispensable for food packaging, and ethylene-vinyl alcohol copolymer, polyvinylidene chloride and polyacrylonitrile are generally used. In particular, ethylene-vinyl alcohol copolymer has an oxygen barrier effect. It is excellent in deep drawability and does not generate harmful gases during incineration, so it is used effectively.

The strength layer is used to give the laminated material a tensile strength, a tear strength, a piercing strength, and to prevent the occurrence of pinholes in portions thinned by molding, and is also excellent in deep drawability. Unstretched nylon is used effectively because of the necessity.

The sealant layer is used for good thermal bonding with the lid material. Low-density polyethylene, linear low-density polyethylene, ionomer, ethylene-vinyl acetate copolymer, etc. are used. , Which has deep drawability and gives a soft feel to the laminated material.
Ethylene vinyl acetate copolymer is advantageously used.

The bottom material is composed of the individual materials described above. It is the above-mentioned modified polyester resin film on the outermost surface that gives the bottom material the dimensional stability of the printing pitch. On the back side of the film, multi-color gravure printing is performed in a multi-imposition layout as shown in FIG. 3, and register marks 14 are simultaneously printed on both ends of the film, so that registration of multi-color printing and pitch dimension control are performed. Used for Since the molding and heat sealing are generally performed with six one-shot surfaces, the bottom material is fed by two products in the flow direction. Therefore, the pitch dimension P is used as a work management standard. From the experience or results so far, it is necessary that the P dimensional accuracy falls within the above-mentioned target accuracy of ± 0.1%.

Next, the molding, filling and sealing steps using the bottom material according to the present invention will be described with reference to FIG. First, the bottom material 1 is supplied in a wound state from a bottom material supply roll 15, heated by a heating unit 16, and immediately subjected to vacuum pressure forming by a forming die 17. Next, in the filling unit 18, after filling the contents,
The vacuum / sealing unit 20 combines the lid material film 2 supplied from the lid material supply roll 19, performs degassing and sealing almost simultaneously, and finally cuts the product into a product size by a cutter 21. In the above steps, the bottom material 1 is intermittently fed by a fixed length in accordance with the printing pitch dimension mechanically determined in the flow direction. In this case, if the printing pitch dimension of the base material varies, it becomes difficult to stop the printing pattern of the base material 1 at the accurate forming and sealing position. Crazy comes. Also, it is difficult to match the registration with the printing of the cover material. In addition, the printing register of the lid material and the bottom material is particularly noticeable,
If it goes crazy, it becomes an unsightly product. Therefore, a tension control mechanism is provided on the lid member side. The printing pitch dimension of the lid is set slightly smaller than the bottom, and when the photoelectric tube 22 catches that the bottom has come to the right position, the bottom is stopped and immediately puts a tension of about 100 kg on the lid to cover the lid. An automatic registering method is employed in which the material pitch is extended and adjusted to the bottom material pitch before sealing.

[0019]

EXAMPLES A bottom material having the following laminated structure was manufactured.

(Example 1) In order from the surface, modified polyester resin 16 μm / polyurethane ink layer / 2-part polyurethane adhesive layer / ethylene vinyl alcohol copolymer layer 15 μm / non-stretched nylon layer 15 μm / ethylene vinyl acetate copolymer A combined layer of 90 μm was laminated by the lamination method. The modified polyester resin of the outermost layer includes a polyester film F865 (melting point 210) of Toray Industries, Inc.
２224 ° C.). Multicolor gravure printing was performed on the back surface of the modified polyester resin film in a layout of six impositions as shown in FIG. The P dimension in FIG.
00 mm. As a result, P dimension accuracy is ± 0.1%
That is, it was confirmed that the distance was within a range of 300 ± 0.3 mm.

Next, a comparison test between the bottom member of Example 1 and the conventional bottom member will be described. As Comparative Example 1, the outermost layer had a polyethylene terephthalate layer of 16 μm,
The second and subsequent layers are made of the same bottom material as in Example 1, and as Comparative Example 2, an unstretched polypropylene layer 5 is formed as the outermost layer.
The test results for the bottom material having a thickness of 0 μm and using exactly the same material for the second and subsequent layers are as follows.

[0022]

[Table 1]

Note: Printing pitch tolerance is 300 ± 0.3
mm, ± 0.1%, molding depth is the depth at the center of the molding die. As is clear from the comparative test, the present invention provides the printing pitch dimensional stability of the bottom material of the deep drawing container and the deep drawing. This enables the supply of bottom materials that simultaneously satisfy the properties.

[0024]

The present invention makes it possible to perform multicolor printing with good registration accuracy of each part also on the bottom material side of the deep drawing container, and by increasing the printing space, the product design effect is enhanced and the image of the product is enhanced. The effect of improving the appeal at stores and stores is improved, and further, by increasing the amount of displayed content, it is possible to provide more accurate information to consumers, and the like.

[Brief description of the drawings]

Fig. 1 Front and sectional view of deep drawing container

FIG. 2 is a configuration diagram of a bottom material laminated structure according to the present invention.

[Fig. 3]

[Figure 4] Process diagram of the form-fill-seal machine

[Explanation of symbols]

1; lid material; 2; bottom material; 3; heat sealing portion; 4; printing of bottom material forming portion; 5; forming portion; 6; punch hole; 7; insufficient molding; 9; printing layer, 10; adhesive layer, 11; oxygen barrier layer, 12; strength layer, 13; sealant layer, 14;
15; bottom material supply roll, 16; heating unit, 17; forming unit,
18; Filling section, 19; Lid supply roll, 20; Degassing / sealing section, 21; Cutter, 22; Phototube, P Dimension for print pitch management

Claims (1)

[Claims] 1. An outermost layer comprising a modified polyester resin film layer having a printing layer on the inner surface on the lamination side, having a melting point in the range of 180 to 230 ° C., and having print pitch dimensional stability, and a sealant layer. A laminated material comprising the other outermost layer and an intermediate layer interposed between the outermost layers, wherein the intermediate layer is at least an oxygen barrier layer and / or pinhole resistance and strength. A bottom material for a deep drawn container, comprising a layer that imparts a thickness, and simultaneously satisfying the dimensional stability of the printing pitch and the deep drawability by vacuum pressure forming.