JPH0661830B2 - How to make a labeled hollow container - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a labeled hollow container, and more specifically, a plastic hollow container having a three-dimensional pattern or structure on the outer peripheral surface of a body. On the other hand, it relates to a method for producing a container in which a label having excellent beauty, durability and peeling resistance is attached to the three-dimensional portion.

(Prior Art) Since plastic hollow containers are excellent in lightweight and impact resistance, various foods, toiletry products, cosmetics,
Widely used for packaging chemicals.

It has long been a matter of course that various types of printing and labeling are performed for the purpose of displaying contents on a plastic container or increasing its commercial value. This printing and sticking of a label are generally performed on a flat surface-like portion of the container body. It is already known that the sticking of the label is performed at the same time as the hollow molding of the container in a container molding die called an in-mold label.

(Problems to be Solved by the Invention) However, if a label can be attached to a portion other than the planar portion of the container body, it is remarkable in terms of aesthetics of the packaging container, commercial value, functionality of the container, and the like. Advantages are expected.

For example, it is common to print a mark indicating the brand or attach a label on which the mark is printed to the packaging container. However, if this mark is a three-dimensional relief pattern, It is expected to improve aesthetics and product value compared to products.

In addition, the packaging container may be required to be provided with a three-dimensional structure in the body part in view of its use and required function. For example, beads and ribs for reinforcing the wall of the vessel, bellows structure that facilitates deformation for extruding contents, pillar and panel structures for preventing deformation during cooling after hot filling correspond to this. . Also in these cases, if the label is attached to the portion including the three-dimensional structure, it is expected that a large display portion can be secured without impairing the original function of the container.

Therefore, an object of the present invention is to provide a plastic hollow container having a three-dimensional pattern or structure on the outer peripheral surface of the body,
It is an object of the present invention to provide a method for producing a labeled hollow container in which a beautiful, durable, and peel-resistant label is firmly applied to the outer periphery of the body including the three-dimensional portion by an in-mold label operation.

(Means for Solving the Problems) According to the present invention, a smooth label made of a surface-printed stretched olefin resin film or a stretched olefin resin film back-printed and provided with a heat-sealing layer on the back-printing layer. A smooth label consisting of is attached to the surface of a blow mold cavity that includes a part for forming a three-dimensional pattern or structure on the outer peripheral surface of the body, and a single-layer or multi-layer plastic parison is placed inside the blow mold. There is provided a method for producing a labeled hollow container, characterized in that it is introduced and melt blow molded into a container, and at the same time, the label is bonded to a body portion including the three-dimensional portion of the container.

(Operation) In the present invention, when a plastic hollow container having a three-dimensional pattern or structure on the outer peripheral surface of the body is manufactured, a smooth label made of a stretched olefin resin film is applied by an in-mold label operation. It is based on the finding that a label having excellent beauty, durability and peel resistance can be attached while faithfully expressing the three-dimensional pattern or structure described above.

A container having a three-dimensional pattern or structure on the outer peripheral surface of the body is pressed in a molten or softened plastic parison in a mold (split mold) having a cavity surface portion corresponding to the pattern or structure. It is obtained by expanding by blowing a fluid, and the expanded plastic comes into contact with the cavity surface of the mold and is cooled. The molded container is taken out by opening the mold. In-mold label operation is performed by holding the label on the cavity surface including the cavity surface portion prior to blow molding of the parison,
The molten plastic parison to be expanded is brought into contact with the label so that thermal bonding proceeds.

In the present invention, at least the inner surface side uses a smooth label composed of a stretched olefin resin film, whereby the plastic of the container body and the stretched olefin resin on the inner surface of the label faithfully reveal a three-dimensional pattern or structure. While still allowing, moreover, a more secure heat bond over the pattern or structure, resulting in a strong bond over the label. This acts as a kind of heat insulating layer when the expanded olefin resin film of the label comes into contact with the expanded container body in the expanded state, and the plastic parison is maintained in the molten state to form the label into a three-dimensional pattern or structure. It is believed that this is due to the fact that it serves as a pressure medium for the above, and that the temperature of the inner surface of the film becomes a high-temperature molten state, and that the thermal adhesion surely proceeds over the entire surface.

This fact will be immediately apparent with reference to FIG. 1 of the accompanying drawings. FIG. 1 shows the elapsed time and temperature of the film outer surface side (mold side) and inner surface side (parison side) when the label film was attached to the cavity surface of the mold and polypropylene parison was blow molded. It is a plot of the relationship. From Fig. 1, the maximum temperature reached on the inner surface side is 175 ° C, while the maximum temperature reached on the outer surface side is 50
It becomes clear that the inner surface side is faster than the outer surface side in the temperature of ℃. Thus, according to the present invention, the film used for the label acts as a heat insulating layer at the time of labeling in the mold, so that the label is first molded into a predetermined three-dimensional pattern or structure by the isotropic pressure transmission of the molten plastic. In addition, the inner surface of the film is melted or heat-activated even by the small amount of heat that the container body has, thereby forming a strong bond between the container body and the label.

Next, when a label is attached to the body of the container by an in-mold label operation, there is a characteristic that there is substantially no step between the outer surface of the body and the outer surface of the label and both surfaces are flush. Considering the adhesive structure between the label and the body of the container, the weakest part of the adhesive structure is the edge of the label, and the adhesive breaks from this edge, causing peeling. On the other hand, in the present invention, it is understood that since the outer surfaces of the both are flush with each other, stress concentration is less likely to occur at the edge portion of the label, and adhesive failure or peeling is less likely to occur.

Moreover, since the label used in the present invention is based on a continuous and thin stretched olefin resin film, it can be molded into a three-dimensional pattern or structure depending on the flexibility, flexibility, and freedom of the film. Done, and when it is once a labeled container, even if the label sticking portion is deformed, the film itself does not break due to flexibility, flexibility, freedom, etc.,
It has excellent durability. Furthermore, since the stretched olefin resin film is excellent in smoothness and continuity, the printed image applied to it is excellent in sharpness, resolution, contrast, density, etc., and it is beautiful and can increase the commercial value. Have.

(Preferred Embodiment of the Invention) The label used in the present invention may have any layer structure within the range of being based on a stretched olefin resin film and having a printing layer.

Some examples of this label are shown in FIGS. 2-A to 2-H. In FIG. 2-A, a label 1 is a stretched olefin resin film substrate 2, and a printing layer 3 provided on the outer surface thereof.
Consists of. The stretched olefin resin film substrate 2 may be a single-layer film or a multi-layer film, but the inner surface side must be heat-adhesive to the plastic container.
The label 1 shown in FIG. 2-B is the same as the label 1 shown in FIG.
-Similar to that of FIG. A transparent resin coat layer is used as the overcoat layer 4. In the label 1 of FIG. 2-C, an adhesive resin layer 5 having thermal adhesiveness is applied to the inner surface side of the film substrate 2 by means of coating or the like. Second
The label 1 in FIG. 2D has the overcoat layer 4 provided on the printed layer 3 in FIG. 2C. Second-E
In the label 1 shown in the figure, the printing layer 3 is applied as so-called back printing on the inner surface side of the film base material 2, and the adhesive resin layer 5 is provided on the printing layer 3. FIG. 2-F shows that the overcoat layer 4 is provided on the outer surface side of the film base material 2 of the label shown in FIG. 2-E. The label 1 in FIG. 2-G has a print layer 3 on the inner surface side of a film substrate 2, a thin metal layer 6 formed thereon by, for example, vapor deposition, and an adhesive resin layer 5 thereon. . This thin metal layer 6 serves to give the printed layer a metallic sheen. FIG. 2-H shows the label of FIG. 2-G in which the overcoat layer 4 is provided on the outer surface side of the film substrate 2. The laminated structure of the label used in the present invention is, of course, not limited to the one exemplified above.

Examples of the olefin resin constituting the film base material of the present invention include crystalline polypropylene and crystalline propylene-
Ethylene copolymer, crystalline polybutene-1, crystalline poly-4-methylpentene-1, low-, medium- or high-density polyethylene, ethylene-vinyl acetate copolymer (EVA),
Examples thereof include ethylene-ethyl acrylate copolymer (EEA) and ion-crosslinked olefin copolymer (ionomer). This film is uniaxially or biaxially stretched. Further, it may be an ordinary transparent film, a film that is slightly foamed, or a semitransparent or opaque film containing a filler or a pigment. The thickness of the film substrate is generally 20 to 300 μm, especially 5
It is suitable to be in the range of 0 to 150 μm.

As the ink for forming the printing layer, an ink known per se used for film printing, for example, polyester urethane, vinyl urethane, acrylic urethane, epoxy urethane, epoxy vinyl, epoxy acrylic, chlorinated polypropylene, etc. is used as a vehicle, and a colorant is used. Ink containing is used. Printing is offset printing, gravure printing,
It may be applied by means of letterpress printing, electrophotographic printing, hot stamping, or the like.

Between the film used for the label and the plastic on the outer surface of the container, it is not particularly necessary when sufficient thermal adhesive strength can be obtained even directly at the time of hollow molding, but in general, via a hot melt adhesive resin, a stretched film substrate and It is preferable to perform thermal bonding with the outer wall plastic of the container. Such a hot melt adhesive resin has a vinyl acetate content of 5 to 40.
% Ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA) having an acrylic acid content of 5 to 40% by weight, low density polyethylene (LDPE), EVA, EEA, etc. Ethylene resin,
Rosin, terpene resin, petroleum resin,
A mixture containing 5 to 30% by weight of a tackifier such as styrene resin is used. The hot melt adhesive resin is generally 3 to 40 μm, especially 5 to 15 μm on the base film.
It is preferable that the thickness is m.

For the overcoat layer, a resin having excellent transparency and scratch resistance, such as nitrocellulose, acrylic resin, acrylic-vinyl paint, acrylic-phenol paint, acrylic-amino paint, etc., is used. The overcoat layer is preferably provided in a thickness of generally 1 to 20 μm, particularly 2 to 10 μm. The thin metal layer can be provided by vapor deposition or hot stamping (transfer) of a metal such as aluminum, and the thickness thereof is generally 0.005 to 15 μm, and particularly 0.01 to 10 μm.

In the present invention, the plastic container body has a three-dimensional pattern or structure on the outer peripheral surface of the body. The three-dimensional shape means that the outer surface changes in the direction perpendicular to the surface direction to form a pattern or structure as the wording says.

In FIGS. 3-A and 3-B showing an example of this hollow container, a bolt-type container 10 includes a body portion 11, a closed bottom portion 12 that extends below the body portion 11, and a mouth portion that connects to an upper portion of the body portion via a shoulder portion 13. Made of 9 The body 11 has a relief pattern 14 protruding outward. The label 1 is applied to the body 11 including the relief pattern 14 by an in-mold label device. In FIG. 3-B showing this sectional structure,
The label 1 is firmly engaged with the container body 11 over its entire surface, but between the outer surface 20 of the label 1 and the outer surface 21 of the container body, that is, the outer surface 21 other than the label sticking portion. There is virtually no step, and it enters in the same plane. That is, label 1
The end edge portion 22 is embedded in the body portion 11 of the container so that the stress is not concentrated on the end edge portion and is prevented from being turned over. In this specific example, the label 1 includes the image portion 26 and the background portion 2 corresponding to the relief pattern 14.
7 and the relief pattern 14 and the image portion 26 coincide with each other, an outstanding relief pattern can be displayed. If the image portion 26 is formed of a metal such as gold or silver or a prominent color such as red, the decorative effect is also large.

FIGS. 4-A and 4-B show an example of a container in which a bead 15 for reinforcement and decoration is formed on the outer periphery of the container body 11, and in this case as well, the bead 15 is included in the outer periphery of the body. Label 1 is similarly attached to.

In FIGS. 5-A, 5-B and 5-C, the structure of the pillar 16 and the panel 17 is provided on the outer periphery of the body 11 for the purpose of preventing asymmetric deformation of the container due to cooling after hot filling. In this example, the internal pressure is compensated by deforming the panel 17 unevenly. Pillar 16 in this example
Also, the label 1 is firmly bonded to the outer circumference of the body including the panel 17.

FIGS. 6-A and 6-B show that the body 11 has a bellows structure, that is, large diameter portions 18 and small diameter portions 19 are alternately provided in the axial direction so as to facilitate the extrusion of the contents. Is. In this example as well, the label 1 including the bellows structure is included.
Are tightly coupled.

The container body 10 of the present invention is, for example, a polyolefin single layer,
Although it may be composed of a polyester single layer or the like, it is preferably composed of a laminated structure of a moisture resistant resin and an oxygen permeation resistant resin from the viewpoint of the storage stability of the contents. In FIG. 7 showing an example of a multi-layer structure of a container, the container 10 is inserted between an oxygen barrier thermoplastic resin intermediate layer 23, moisture resistant thermoplastic resin inner and outer layers 24a and 24b and, if necessary, both resins. It is composed of adhesive resin layers 25a and 25b.

In the present invention, the oxygen permeability coefficient (PO ₂ ) is 5.5 × 10 ⁻¹² cc · cm / cm ² · sec · cmH in terms of storage stability and aroma retention of the content.
g (37 ℃, 0% RH) or less, especially 4.5 × 10 ^-12 cc ・ cm / cm
It is preferable to use a thermoplastic resin having a viscosity of ² sec · cmHg or less alone or a blend of resins as the oxygen barrier resin.

The most preferable example of such a resin is an ethylene-vinyl alcohol copolymer, particularly one having a vinyl alcohol unit content of 40 to 85 mol%, particularly 50 to 80 mol%. Such an ethylene-vinyl alcohol copolymer is a copolymer of ethylene or a majority of ethylene and a minor component of another olefin such as propylene, and a vinyl ester of a lower fatty acid such as vinyl formate, vinyl acetate or vinyl propionate. It is obtained by saponifying a polymer, particularly an ethylene-vinyl acetate polymer, so that the saponification degree is 96% or more, particularly 99% or more.

Other examples of the oxygen barrier resin include nylon resin,
Especially nylon 6, nylon 8, nylon 11, nylon 12, nylon 6.6, nylon 6/10, nylon 1
0.6, or nylon 6- / 6/6 copolymer can be mentioned.

Further, high nitrile resin, vinylidene chloride resin, vinyl chloride resin and the like can be used for the purpose of the present invention.

The oxygen barrier resin can be used in the form of a so-called blend, for example, a blend of an ethylene-vinyl alcohol copolymer and a nylon resin can be used, and further, an ethylene-vinyl alcohol copolymer can be used. , Other resins such as polyethylene, ethylene-vinyl acetate copolymer, or a blend with an ionomer can be used for the purpose of the present invention as long as the oxygen permeability coefficient is within the above range.

As the moisture-resistant thermoplastic resin, olefin resins such as bottom-medium- or high-density polyethylene polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, and ionomer are preferably used.

When there is no interlayer adhesion between the oxygen barrier resin and the moisture resistant resin, an adhesive layer is interposed between both resin layers.

As the adhesive resin (C), any resin that exhibits adhesiveness to both the oxygen barrier thermoplastic resin (A) and the moisture resistant thermoplastic resin (B) described above is used.
Examples of such adhesive resin (C) generally include free carboxylic acid, carboxylic acid salt, carboxylic acid ester, carboxylic acid amide, carboxylic acid anhydride, carbonic acid ester, urethane,
Carbonyl group based on functional groups such as urea A thermoplastic polymer containing or a blend of these polymers with another thermoplastic polymer is used. The concentration of carbonyl groups in these thermoplastic polymers may vary, but in general, the carbonyl group content is 10 to 1400 mmol / 100 g, especially 30 to 1200 mmol / 1.
It is desirable that the polymer be contained at a concentration of 00 g of polymer. Suitable adhesives include unsaturated acid carboxylic acids, acid anhydrides, esters,
Polyolefins modified with at least one ethylenically unsaturated monomer among amides, especially maleic acid, acrylic acid, methacrylic acid, crotonic acid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride, citraconic anhydride Polypropylene modified with acid, ethyl acrylate, methyl methacrylate, ethyl maleate, 2-ethylhexyl acrylate, acrylic acid amide, methacrylic acid amide, coconut oil fatty acid amide, maleimide, high density polyethylene, low density polyethylene , Ethylene-vinyl acetate copolymers, etc., and also ethylene-acrylate copolymers, ionomers (Surrin A manufactured by DuPont), polyalkylene oxide / polyester block copolymers, carboxymethylcellulose derivatives, or poly (iodine) and these. A blend products of the fin class. It should be noted that any of these resins having a low carbonyl group content can be used as a moisture resistant resin itself.

The body of the container of the present invention is generally 100 to 300.
It preferably has a thickness of 0 μm, especially 200 to 1000 μm.

In FIG. 8 for explaining the in-mold label operation, in step A, the blow split molds 30a and 30b are in an open state prior to the blow molding of the plastic parison.
The label 1 is preliminarily applied to a portion 31 of the surface of at least one of these cavities where a three-dimensional pattern or structure is to be formed. That is, the cavity surface 31 has a portion for supporting the label 1, and the depressurizing suction mechanism 32 is provided in this portion.
Held at 1. In this case, the label has a positional relationship in which the stretched olefin resin is on the inside. The application and fixing of the label 1 to the cavity surface 31 can be performed not only by suction but also by static electricity, for example.

Next, in step B, the molten plastic parison 34 is extruded from the die 33, and blow blow molds 30a, 30b.
Is closed, and pressurized gas is blown into the closed parison 34.

In step C, the parison that expands in the mold is held on the mold surface and pressed against the label 1 to bring them into close contact, and the expanded parison comes into contact with the mold surface and is cooled, whereby the labeled container 10 Becomes

Blow molding is performed by any blow molding method such as injection blow, two-stage blow, sheet forming, stretch blow, etc. in addition to the direct blow method using a horizontal rotary blow molding machine or a vertical rotary blow molding machine. be able to.

(Effect of the Invention) According to the present invention, the heat insulation of the film is achieved by applying the label of the stretched olefin resin film base to the plastic container provided with the three-dimensional pattern or structure on the outer periphery of the body by the in-mold label operation. By the action, the label surface and the container body can be firmly bonded by thermal bonding while faithfully revealing the three-dimensional pattern or structure. Further, the outer surface of the label and the outer surface of the body of the container are flush with each other without a step, and the stress concentration on the edge portion of the label is released, resulting in excellent peeling resistance. Further, by using a film-based label, the film is not damaged by the flexibility, flexibility, freedom, etc. of the film, and has excellent durability. Furthermore, since the film is excellent in smoothness and continuity, the printed image applied to it is excellent in sharpness, resolution, contrast, density, etc., and it is possible to enhance the beauty and commercial value. .

(Example) The present invention will be described in the following example.

Example 1 A 100 μm-thick heat-shrinkable biaxially stretched film having a melting point of 137 ° C. and a heat-shrinkable biaxially stretched film was subjected to star-shaped design printing on one side thereof, and chlorinated polypropylene 50 was further applied thereto. A sealant consisting of a blend of 50 parts by weight and 50 parts by weight of ethylene-vinyl acetate copolymer was applied.

Then, a rectangular label measuring 80 mm in length and 60 mm in width was punched out from the obtained label substrate, and a mold having a star-shaped recess in the center of the bottle body was used to perform the process shown in FIG. It was attached to a bottle made of high-density polyethylene having a shape as shown in. In this case, the high density polyethylene parison had a molten resin temperature of 220 ° C and a blow mold temperature of 9 ° C. In addition, the temperature of the label bonding surface during blow molding reached a maximum of 175 ° C.

The appearance of the star-shaped relief part of the body part of the in-mold label bottle thus obtained was very good, the label adhered following the curved surface of the relief, and no pimples or wrinkles were observed.

Examples 2 to 4 Using the same label material and bottle material as in Example 1, the steps shown in FIG. 8 were used to carry out FIGS. 4 (Example 2), 5 (Example 3) and 6 An in-mold label bottle having a shape as shown in the figure (Example 4) was molded.

The follow-up of the label to the three-dimensional curved surface of the in-mold label bottle body thus obtained is very good,
No pimples or wrinkles were observed.

Examples 5 to 8 Using the various label materials and bottle materials shown in Table 1, an in-mold label bottle having a shape as shown in FIG. 3 was molded in the same manner as in Example 1. The appearance of the obtained bottle was very good, and the label adhered following the curved surface of the star-shaped relief, and no pimples or wrinkles were observed.

[Brief description of drawings]

FIG. 1 is a diagram in which the temperature of the label surface and the mold surface when the in-mold label of the present invention is attached to a bottle is plotted in relation to the elapsed time, and FIG. 2 is a graph of the label used in the present invention. It is a figure which shows the example of a cross-section structure, FIG. 3 is a figure which shows the example of the container which has a three-dimensional relief pattern on the outer peripheral surface of the container body of this invention, and FIG. 4 is the container body of this invention. It is a figure which shows the example of the container in which the bead is formed in the outer periphery of a part, and FIG. 5 is a figure which shows the example of the container in which the pillar and the panel are provided in order to prevent deformation in the outer periphery of the container body of this invention. FIG. 6 is a diagram showing an example of a container in which a bellows structure is provided on the container body of the present invention so that the contents can be easily extruded, and FIG. 7 is a container body of the present invention. FIG. 8 is a diagram showing an example of the cross-sectional structure of FIG. 8, and FIG. 8 is a diagram for explaining the in-mold label operation, Irradiation numeral 1 label, 2 a plastic film substrate,
3 is a printing layer, 4 is an overcoat layer, 5 is an adhesive resin layer, 6 is a thin metal layer, 10 is a labeled container, 14 is a relief pattern, 15 is a bead, 16 is a pillar, 17 is a panel, 30 is a Blow split type, 31 is a cavity surface, 32 is a reduced pressure suction mechanism, 33 is a die, and 34 is a parison.

Claims (1)

[Claims] 1. A smooth label made of a front-printed stretched olefin resin film or a smooth label made of a back-printed stretched olefin resin film having a heat-sealing layer provided on the back-printing layer is provided on the outer peripheral surface of the body. Is adhered to the surface of a blow mold cavity containing a portion for forming a three-dimensional pattern or structure, and a single-layer or multi-layer plastic parison is introduced into the blow mold to melt-blow-mold into a container and at the same time. A method for producing a labeled hollow container, characterized in that a label is bonded to a body portion including the three-dimensional portion of the container.