JP3202035B2 - Polyethylene terephthalate film laminate can - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a can for food and drink, and more particularly to a can having a biaxially stretched polyethylene terephthalate film laminated on the outer surface of a can body.

[0002]

2. Description of the Related Art Conventionally, when a pattern is formed on the outer surface of a metal can body, a coating layer made of white paint is formed on the outer surface side of the can of a surface-treated steel sheet forming a can body, and then the coating layer is formed on the coating layer. Has been printed. The can body manufactured by such a method requires many printings for color matching, and the process becomes complicated. In addition, baking is performed for forming a coating layer using a white paint and printing, and a finishing varnish coat is performed on the upper layer of the printing. This requires large equipment and consumes a lot of energy. In the baking step, there is a problem that the environment in the workplace is deteriorated due to the evaporation of the solvent and an increase in the temperature.

On the other hand, a can body in which a biaxially stretched polyethylene terephthalate (OPET) film is laminated on the outer surface of a metal can body is known. In such a can body, O
After printing on the outer surface of the PET film, finishing varnish coating on the printing surface and baking, the OPET film is adhered to the can body of the metal can body on the unprinted surface, or the OPET film After laminating a surface-treated steel sheet into a can body, printing is performed on the outer surface of the OPET film for each can, finish varnish coating is performed on the printed surface, and baking is performed. For printing an OPET film, for example, an ink in which a pigment is dispersed in a binder of a synthetic resin such as a urethane resin, a polyester resin, and an acrylic resin is used.

According to the above technique, since printing is performed on the OPET film, the process can be simplified as compared with a case where printing is directly performed on the material forming the can body. Although a drying oven is required for baking, the size can be reduced compared to printing on a surface-treated steel sheet, and a closed-type oven can be used, preventing solvent evaporation and temperature rise. And the working environment is not deteriorated.

However, in any of the above-mentioned can bodies having the outer surface of the OPET film printed thereon, the outer surface of the can is rubbed or collides with something when subjected to a high temperature treatment for heat sterilization or the like, and receives an impact. And the printing surface is scratched or OP
The pattern formed by peeling off the printed part of the ET film may be damaged, which may reduce the commercial value. Therefore, in order to solve the above problem, it is conceivable that printing is performed on the surface of the OPET film on the can body side, and the printed surface is adhered to the can body.

However, when printing is performed on the surface of the OPET film on the can body side, the film surface is covered with the printing ink and is not exposed. There is an inconvenience that uniform adhesion cannot be achieved.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a can body in which the pattern formed on the outer surface of the can body is hardly damaged even when the treatment is performed under a high temperature condition.

[0008]

In order to achieve the above object, a polyethylene terephthalate film laminate can of the present invention comprises a biaxially stretched polyethylene terephthalate film having one surface printed thereon and a white paint coated on the printing surface side. With or without interposition, a thermocompression bonding is performed on the outer surface side of the can of the surface-treated steel sheet forming the can body via the adhesive layer.

The adhesive layer may contain a coloring agent such as a white pigment , if desired. Further, in the case of performing via a white paint, a method of applying a white paint on the printing surface on the film side to form a coating film and then bonding the coating to a metal surface via an adhesive layer, or a can of the metal plate A suitable method is to coat the outer side with a white paint and then bond the printed film via an adhesive layer.

As the thermosetting epoxy resin adhesive, one or two of a bisphenol epoxy resin , a resol phenol resin, an acrylic resin, an aminoplast resin, a polyester resin, a urethane resin and a polysiloxane resin are used. It can be used an adhesive consisting of a mixture of species or more, particularly, a bisphenol type epoxy resin and a resol type phenol resin 98 / 2-50 / 50
The epoxy phenol resin blended at a weight ratio of:

The white paint is a resin composed of one or a mixture of two or more of bisphenol type epoxy resin, resol type phenol resin, acrylic resin, aminoplast resin, polyester resin, urethane resin, polysiloxane resin and the like. And a coating material in which a pigment such as titanium oxide is dispersed.

[0012]

According to the polyethylene terephthalate film laminate can of the present invention, a urethane resin is provided on one surface,
Polyester resin, an OPET film printed with an ink in which a pigment is dispersed in a binder of a synthetic resin such as an acrylic resin, and the like on a printing surface side of a metal plate forming a can body via an adhesive layer. Since it is thermocompression bonded to the outer surface of the can,
The pattern formed on the outer surface of the can body by the printed OPET film is protected by the outer OPET film, and is not damaged even when the can body is processed under high temperature conditions.

The adhesive layer is made of a thermosetting epoxy resin-based adhesive, and has an adhesive force to both a printing surface and a metal plate on which ink or the like in which a pigment is dispersed in a binder of the synthetic resin is dried and cured. As a result, the OPET film is uniformly adhered to the metal plate even though the film surface is covered with the ink and the resin is not exposed. Therefore, even in a heat treatment step such as heat sterilization after filling the contents, the OPET film does not peel off from the metal plate, and the pattern formed on the outer surface of the can body is effectively protected.

When the metal plate is coated on its outer surface with a polyester-based white paint, the affinity with the adhesive layer is improved, and a strong adhesive force is obtained. In addition, by providing a white paint layer between the printing surface of the OPET film and the side of the metal plate that becomes the outer surface of the can, the pattern formed on the outer surface of the can body by the OPET film becomes clearer.

[0015]

Embodiment 1 FIG. 1 is a cross-sectional view of a can body blank 11 forming a can body in a polyethylene terephthalate film laminated can body of the present embodiment. Can body blank 11
Is a biaxially stretched polyethylene terephthalate (OPET) printed on one side, except for the welded seams 13 at both ends, on the side of the tin-plated surface-treated steel sheet 12 to be the outer surface of the can.
The film 14 has a printing surface 15 on a tin-plated surface-treated steel plate 12.
On the side, it is bonded via a thermosetting epoxy resin adhesive layer 16. An epoxy-phenol resin layer 17 is formed on the inner surface of the tin-plated surface-treated steel sheet 12 except for welded joints 13 at both ends.

The can body blank 11 was manufactured as follows. First, a corona discharge treatment was performed on one surface of the OPET film 14 having a thickness of 12 μm, and printing was performed using an ink in which a pigment was dispersed in a binder of a synthetic resin to form a printing surface 15. Next, a 3.0 g / m ² thermosetting epoxy resin-based adhesive is applied to the printing surface 15 of the OPET film 14, and dried by heating at 120 ° C. for 60 seconds using a dryer oven. Adhesive layer 16
Was obtained. In this example, an epoxy-phenol resin solution in which a bisphenol-type epoxy resin and a resole-type phenol resin were mixed at a weight ratio of 80/20 was used as the thermosetting epoxy resin-based adhesive.

Next, 6 g / m ^{2 of} an epoxy phenol resin, except for the welded seams 13 at both ends, is provided on the side of the surface-treated steel sheet 12 having a surface plated with 0.7 g / m ² of tin, which is the inner surface of the can. And baked by heating at a temperature of 205 ° C. for 10 minutes using an oven to form an epoxy-phenol resin layer 17.

The surface-treated steel sheet 12 on which the epoxy-phenol resin layer 17 is formed is heated to 200 ° C., and the laminating film is applied to a portion other than the welding seam portion 13 on the outer surface of the can via an adhesive layer 16. Lamination, 4kg
/ M ² pressure rolls and then thermocompression bonded, then cooled,
The can body blank 1 in which the OPET film 14 is adhered on the printing surface 15 side, and a pattern is formed on the outer surface of the can body.
1 was obtained.

Next, both ends 1 of the can body blank 11
3 were overlapped and welded using a known pressure seam welding machine to obtain a can body. Next, a solvent-type epoxy phenolic resin paint is applied to the exposed metal joints on the inner and outer surfaces of the can body and heated and baked at a temperature of 210 ° C. for 60 seconds to form a resin coating layer, and the coating is corrected. Was.

Next, a bottom cover is formed by applying neck-in processing and flange processing to both ends of the can body, and coating and baking an epoxy phenol resin on the inner surface on one end thereof to form a resin coating layer. Was wound twice to obtain a welded can body.

Next, the welding can body is filled with milk coffee, and the open end is coated with an epoxy phenol resin on the inner surface side and baked to form a double canopy having a resin coating layer formed thereon. The product was wound and canned.

After the canned product was heat-sterilized, the outer surface of the can was inspected. As a result, the formed pattern was not damaged at all, and the OPET film 14 was not peeled off.

[0023]

Embodiment 2 FIG. 2 is a cross-sectional view of a can body blank 21 forming a can body in a polyethylene terephthalate film laminated can body of the present embodiment. Can body blank 21
On the side of the tin-plated surface-treated steel sheet 12, which is to be the outer surface of the can, except for the welded seams 13 at both ends, the OPET film 14 printed on one side changes the printing surface 15 to the tin-plated surface-treated steel sheet 12 side. Then, they are bonded via a thermosetting epoxy resin-based adhesive layer 16. An OPET film 22 is adhered to the inner surface of the tin-plated surface-treated steel sheet 12 via a thermosetting epoxy resin-based adhesive layer 23 except for welded joints 13 at both ends.

The can body blank 21 was manufactured as follows. First, in the same manner as in Example 1, a 12 μm-thick O
A printing film 15 was formed on one surface of the PET film 14 and an adhesive layer 16 was formed on the printing surface 15 to obtain a laminating film. Further, an adhesive layer 23 was formed on one surface of the same OPET film 22 as in the case of the laminating film to obtain a laminating film on which no printing was performed.

Next, the surface-treated steel sheet 12 having a surface plated with tin of 0.7 g / m ² is heated to 200 ° C., and the printed laminating film is formed on the outer surface of the can. After laminating the unprinted laminating films on the sides except for the welded seams 13 via the adhesive layers 16 and 23, and simultaneously thermocompression-bonded through 4 kg / m ² pressure rolls After cooling, a can body blank 21 covered on both sides with OPET films 14 and 22 was obtained. On the side of the outer surface of the can body blank, a pattern is formed by the printed OPET film 14.

Next, both ends 1 of the can body blank 21
3 were overlapped and welded using a known pressure seam welding machine to obtain a can body. Next, a solvent-type epoxy phenolic resin paint is applied to the exposed metal joints on the inner and outer surfaces of the can body and heated and baked at a temperature of 210 ° C. for 60 seconds to form a resin coating layer, and the coating is corrected. Was.

Next, neck-in processing and flange processing are performed on both ends of the can body, and a bottom lid whose inner surface is covered with an OPET film is double-tightened on one end of the can body to form a welded can body. I got The bottom cover is made of a surface-treated steel sheet having metal chromium and chromium oxide formed on the surface, and the inner surface thereof is OPE in the same manner as the can body blank.
Covered with T film.

Next, the welding can body is filled with coffee,
An aluminum easy-open can lid was double-wrapped around the open end to produce a can. The inner surface side of the easy open can lid is covered with an OPET film in the same manner as the can body blank.

After heat-sterilizing this can, the outer surface of the can body was examined. As a result, the formed pattern was not damaged at all, and the OPET film 14 was not peeled off.

The thermosetting epoxy resin-based adhesive used in Examples 1 and 2 has an excellent affinity for the printing ink surface 15 on the surface of the OPET film 14 and the surface-treated steel sheet 12, and is composed of the adhesive. OP via the adhesive layer 16
By thermocompression bonding of the ET film 14, the OPET film 14 was able to be uniformly adhered to the surface-treated steel sheet 12 on the printed surface 15 thereof.

[0031]

Embodiment 3 FIG. 3 is a cross-sectional view of a can body blank 31 forming a can body in the polyethylene terephthalate film laminate can of this embodiment. Can body blank 31
The OPET film 14 having a polyester-based white paint layer 32 formed on the side of the tin-plated surface-treated steel sheet 12 which is to be the outer surface of the can except for the welded seams 13 at both ends, and having one surface printed thereon Are adhered on the polyester-based white paint layer 32 via the thermosetting epoxy resin-based adhesive layer 16 with the printed surface 15 facing the tin-plated surface-treated steel sheet 12. An OPET film 22 is adhered to the inner surface of the tin-plated surface-treated steel sheet 12 via a thermosetting epoxy resin-based adhesive layer 23 except for welded joints 13 at both ends.

The can body blank 31 is coated with 15 g / m ² of a polyester-based white paint on the surface of the surface-treated steel sheet 12 which is to be the outer surface of the can, heated at 190 ° C. for 10 minutes and baked to form a polyester-based white paint layer. 32, except that OPE 32 was used.
A can body blank coated with a T film was obtained. On the side of the outer surface of the can body blank, a pattern is formed by the printed OPET film.

Next, a can was manufactured using the can body blank 31 in the same manner as in Example 2, and the can was heat-sterilized. After inspecting the outer surface of the can body, the formed pattern was completely damaged. No peeling of the OPET film 14 was observed.

The thermosetting epoxy resin adhesive used in Example 3 is the printing ink surface 1 on the surface of the OPET film 14.
5 and the surface-treated steel sheet 12 have an excellent affinity for the polyester-based white paint layer 32, and the OPET film 14 is heat-pressed through the adhesive layer 16 made of the adhesive, so that the OPET film 14 Printing side 1
5 was able to adhere uniformly to the surface-treated steel sheet 12.

[0035]

Embodiment 4 FIG. 4 is a sectional view of a can body blank 41 forming a can body in a polyethylene terephthalate film laminated can body of the present embodiment. Can body blank 41
Is TF with metal chromium and chromium oxide formed on the surface
A weld seam 1 at both ends is provided on the side of the S
Except for Example 3, the OPET film 14 having one surface printed is adhered via the thermosetting epoxy resin adhesive layer 16 with the printed surface 15 facing the TFS steel plate 42. The OPET film 22 is bonded to the inner surface of the can of the TFS steel plate 42 via the thermosetting epoxy resin adhesive layer 23 except for the welded seams 13 at both ends.

The can body blank 41 was manufactured in the same manner as in Example 2 except that a TFS steel sheet 42 having metal chromium and chromium oxide formed on the surface was used. The both sides were covered with OPET films 14 and 22. A can body blank 41 was obtained. On the side of the outer surface of the can body blank 41, a pattern is formed by the printed OPET film 14.

Next, a can was manufactured in the same manner as in Example 2 using the can body blank 41, and the can was heat-sterilized. After inspecting the outer surface of the can body, the formed pattern was completely damaged. No peeling of the OPET film 14 was observed.

The thermosetting epoxy resin adhesive used in Example 4 was the printing ink surface 1 on the surface of the OPET film 14.
5 and the surface of the TFS steel sheet 42. The OPET film 14 is thermocompressed through the adhesive layer 16 made of the adhesive.
Was uniformly adhered to the TFS steel plate 42 on the printed surface 15.

In each of the above embodiments, a thin tin-plated steel plate 12 or a TFS surface-treated steel plate 4 having metal chromium and chromium oxide formed on the surface is used for forming the body of the can.
2, but the material of the can body is not limited to this, and another metal such as aluminum may be used as the material. Further, in each of the above embodiments, a welded can body is formed, but may be applied to an adhesive can body. Furthermore, the present invention may be applied to a two-piece can by printing in consideration of the distortion of the design after molding.

[0040]

As is apparent from the above, according to the polyethylene terephthalate film laminate can of the present invention, a pigment is added to one surface of a synthetic resin binder such as a urethane resin, a polyester resin or an acrylic resin. An OPET film printed with an ink or the like in which is dispersed is thermocompression-bonded on the printing surface side to the outer surface side of a metal plate forming a can body via an adhesive layer, so that the printed OPET film is Thus, the pattern formed on the outer surface of the can body can be protected by the OPET film, and damage can be prevented.

The adhesive layer is made of a thermosetting epoxy resin-based adhesive, and has an adhesive strength to both the printing surface and the metal plate on which the ink has been dried and cured.
Although the film surface is covered with the ink and the resin is not exposed, the film can be uniformly bonded to the metal plate. Therefore, even in a heat treatment step such as heat sterilization after filling the contents, the OPET film does not peel off from the metal plate, and the design formed on the outer surface of the can body can be effectively protected.

When the metal plate is coated on its outer surface with a polyester-based white paint, affinity with the adhesive layer is improved, and a strong adhesive force can be obtained. Further, by interposing a white paint layer between the printing surface and the side of the metal plate that becomes the outer surface of the can, an effect is obtained in that the pattern formed on the outer surface of the can body by the OPET film becomes clearer. Can be

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a can body blank forming a can body in a polyethylene terephthalate film laminate can of Example 1.

FIG. 2 is a cross-sectional view of a can body blank forming a can body in the polyethylene terephthalate film laminate can of Example 2.

FIG. 3 is a cross-sectional view of a can body blank forming a can body in the polyethylene terephthalate film laminate can of Example 3.

FIG. 4 is a sectional view of a can body blank forming a can body in the polyethylene terephthalate film laminate can of Example 4.

[Explanation of symbols]

11, 21, 31, 41 ... can body blank, 12, 42 ...
Metal plate, 14: Biaxially stretched polyethylene terephthalate film 15: Printing surface, 16: Adhesive layer.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 B29C 65/48-65/54

Claims (2)

(57) [Claims] 1. A one biaxially oriented polyethylene terephthalate film subjected to printing on the surface in the printing surface, bisphenol
Epoxy resin and resole phenolic resin,
Krill resin, aminoplast resin, polyester resin,
One or two of urethane resin and polysiloxane resin
A polyethylene terephthalate film laminate can body, which is thermocompression-bonded to the outer surface side of a metal plate forming a can body via a thermosetting epoxy resin-based adhesive layer made of a mixture of at least one of the above . 2. The polyethylene terephthalate film laminate can according to claim 1, wherein the metal plate is coated with a white paint on the outer surface of the can.