JP2003206362A - Resin composition for overcoat for plastic film and its use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition that is used for overcoat for a plastic film with a printing layer applied on the surface thereof for coating a tubular body portion (a can body portion) of a bottomed tube covered with a plastic film and that is capable of forming a overcoat layer excellent in heat resistance, adhesion, slipperiness, stain resistance or the like. <P>SOLUTION: The resin composition for overcoat for a plastic film comprises (A) an epoxy resin having a number average molecular weight of 1,500-6,000 and an epoxy equivalent of 800-5,000, (B) an epoxy resin having a number average molecular weight of 900-1,300 and an epoxy equivalent of 180-500, (C) a branched polyester resin having a number average molecular weight of 5,000-15,000, (D) an amino resin, (E) a blocked or non-blocked polyisocyanate compound and (F) a silicone compound having a functional group capable of reacting with at least one of the components (A) to (E). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an overcoat resin composition for a plastic film, and more particularly to an overcoat resin composition suitably used for a plastic film for coating the outer surface of a can body of a beverage can or a food can. . Furthermore, the present invention relates to the use of the above-mentioned overcoat resin composition, specifically, a plastic film with an overcoat layer and the like, in which the printed layer of the plastic film with a printed layer is covered with the above overcoat resin composition, and The present invention relates to a plastic film-coated metal can coated with a plastic film having an overcoat layer or the like.

[0002]

2. Description of the Related Art Conventionally, various coatings and printings have been applied to the inner and outer surfaces of cans for storing and containing foods and beverages (hereinafter referred to as beverages) for the purpose of imparting corrosion resistance and decorativeness, respectively. There is. By the way, beverage cans can be roughly classified into three-piece cans and two-piece cans according to their forms. The three-piece can is composed of a cylindrical side member, that is, a can body member, a bottom member, and a lid member. On the other hand, a two-piece can is composed of an integrated can body / bottom, that is, a bottomed tubular member and a lid member. The can body of a three-piece can among these cans is generally a metal plate that has been cut into a predetermined size in advance, after applying an inner coating material and an outer surface undercoating material, a printing layer is provided on the outer surface side, and After applying the external finish paint to, cut it into a quadrangle of the size of each can, then round the quadrilateral metal plate into a cylindrical shape,
It is formed by adhering or welding the end faces. After that, a process (neck-in process, flanging process, etc.) of shrinking the upper end and the lower end of the cylindrical can body is performed. On the other hand, of these cans, the integrated body and bottom of the two-piece can is made by forming a metal plate for one can into a cylinder with a bottom, applying the inner paint and the undercoat paint on the outer surface, and then printing on the outer surface. It is formed by providing a layer and applying an external finish paint on the printed layer.

In recent years, in both two-piece cans and three-piece cans, in addition to the above-described method of directly applying a paint or printing ink on the metal, the inner and outer surfaces of the metal of the can body are A method of coating with a plastic film has been proposed.

(A) Three-piece can The body of the three-piece can can be formed, for example, by the following method. (A-1) An adhesive layer-attached plastic film for metal outer surface coating, which comprises a printing layer provided on one surface of a plastic film for outer surface coating and an adhesive layer provided on the printing layer, is obtained. A plastic film-covered metal plate is obtained by laminating a plastic film for coating a metal inner surface on one surface and an adhesive layer of the plastic film with an adhesive layer for coating a metal outer surface on the other surface of a metal plate. It is formed by cutting a film-coated metal plate into a quadrilateral having a size for each can, then rolling the quadrilateral metal plate into a cylindrical shape and adhering and welding the ends.

(A-2) A metal-coated plastic film with an adhesive layer for external surface coating, wherein a printed layer is provided on one surface of the plastic film for external surface coating and an adhesive layer is provided on the other surface of the plastic film. A plastic film for metal inner surface coating on one surface of the plate, a plastic film-coated metal plate obtained by laminating an adhesive layer of the plastic film with an adhesive layer for metal outer surface coating on the other surface of the metal plate, It is formed by cutting the plastic film-covered metal plate into a quadrangle having a size for each can, then rolling the quadrilateral metal plate into a cylindrical shape, and bonding and welding the ends.

(B) Two-piece can (B-1) On the other hand, the bottomed tubular portion of the two-piece can has a plastic film for coating the inner metal surface on one surface of the metal plate and a metal film on the other surface of the metal plate. After laminating each of the plastic films for coating the outer surface to obtain a metal plate whose both surfaces are coated with the plastic film, the plastic film-coated metal plate is punched for each can, and the punched product is formed into a bottomed tubular shape, and then a tubular shape. It is formed by providing a printing layer by offset printing on the outer surface of the plate-like portion (can body portion), and applying an outer surface finish paint (overcoat paint) on the print layer to impart scratch resistance.

However, in the offset printing, the number of colors to be printed in one step is limited, and since it is printed on the curved surface of the tubular portion (can body portion), it is difficult to align the position and overprinting is not possible, so that the appearance is sufficient. There is an inconvenience that it cannot be given. Further, the can-making speed itself is as high as 1000 cans per minute or more, and if the curved surface printing speed is made to correspond to the can-making speed, it becomes more difficult to stably perform beautiful printing. . Further, since the metal can body is often manufactured in small lots with a large variety of products with a small production amount for each lot, the frequency of exchanging the plate mold for the offset printing becomes high and the productivity is lowered. .

(B-2) Then, in order to eliminate such inconvenience and to impart excellent aesthetic properties to the outer surface side of the can body of the metal can body formed from a metal plate into a bottomed tubular shape,
A plastic film with an adhesive layer provided with a printing layer that is aesthetically pleasing and has a high-grade appearance by gravure printing, etc., so that it goes around the outer surface of the can body of a metal can body formed from a metal plate into a bottomed tubular shape. The coating method is disclosed in JP-A-04-057747.
Japanese Patent Laid-Open No. 07-089552, Japanese Patent Laid-Open No. 09-09552
It was proposed in Japanese Patent Publication No. -029842. According to this method, the outer surface of the can body can be provided with a printing layer having a good appearance and a high quality appearance, but there is a problem that the can bottom and the vicinity of the can bottom cannot be covered with a plastic film.

(B-3) In order to solve such a problem, a plastic film-covered metal plate obtained by laminating a plastic film for coating on at least one surface of a metal plate is obtained. The plate is punched for each can, and the punched product is formed into a cylinder with a bottom so that the plastic film is on the outside, and then on the plastic film on the outer surface of the cylinder part (can body) of the plastic film-covered bottom cylinder. In addition, a method of separately laminating a plastic film with an adhesive layer, which is provided with a printing layer having excellent beauty and high quality by gravure printing etc.
It was proposed in Japanese Patent Publication No. 00-177745.

In the cases of (A), (B-2), and (B-3), a metal plate for a can body portion, an outer surface of a tubular portion (can body portion) of a bottomed tubular metal can body, or A plastic film on the outer surface of the tubular part (can body) of the plastic film-covered bottomed cylinder (hereinafter, the three may be collectively referred to as a can body member).
Then, a plastic film provided with a printing layer is adhered and laminated on both of them via an adhesive layer. Since it has an advantage that it can be easily attached and laminated because it is via an adhesive layer, the cost of the adhesive itself is extra compared to the case where no adhesive is used, and the process of forming the adhesive layer on the plastic film Since the extra is also required, the produced plastic film with an adhesive layer, and the can body and the final can body formed from the plastic film are expensive.

Therefore, in order to form a cheaper can body or can body, it is required to laminate a plastic film with a printing layer on a can body member without providing an adhesive layer.
As a method of laminating a plastic film with a printing layer on a can body member without providing an adhesive layer, the plastic film itself is appropriately softened or melted by heat and adhered to the can body member under pressure. A method can be considered (hereinafter referred to as thermocompression bonding). In the case of the thermocompression bonding method, the plastic film and the printing layer are generally exposed to a higher temperature than when an adhesive is used.

By the way, (A), (B-2), (B-
The plastic film with an adhesive layer of 3) has two major modes of "back printing" and "front printing" depending on the position where the printing layer is provided. That is, (a) "reverse printing" type: a plastic film with an adhesive layer in which a plastic film, a printing layer, and an adhesive layer are sequentially laminated. In this type, a plastic film with an adhesive layer is attached and laminated on the outer surface of the can body member, and then the printed layer formed on the back surface of the plastic film is viewed through the plastic film. Above (A-
1) is a "reverse printing" type. (B) “Front printing” type: A plastic film with an adhesive layer, which is formed by sequentially stacking a printing layer, a plastic film, and an adhesive layer. This is a type in which a plastic layer-attached plastic film is attached and laminated on the outer surface of a can body member, and then the printed layer formed on the plastic film is viewed. The above-mentioned (A-2) is a “front printing” type.

Comparing "back printing" and "front printing" from the viewpoint of the aesthetic appearance of the printing layer, "back printing" is generally more beautiful, so "back printing" is preferred. However, when laminating a plastic film provided with a "back printing" printing layer by a thermocompression bonding method without using an adhesive on the body member of the can, the plastic film is positioned at the laminating interface due to heat when softening or melting. The printed layer is damaged or the aesthetic appearance is significantly impaired. Therefore, when a plastic film provided with a printing layer is laminated on a can body member by a thermocompression bonding method without using an adhesive, the printing layer needs to be a "front printing" type.

Also, when a plastic film with a printing layer is laminated on the outer surface of the can body member by thermocompression bonding,
As in the case of (B-1), an outer surface finish paint (overcoat paint) layer is provided on the plastic film covering the body of the can in order to impart scratch resistance. As a method of providing an external finish paint (overcoat paint) layer, (1) a method of applying an external finish paint (overcoat paint) after laminating a plastic film with a printing layer on the outer surface of a can body member (2) A method of forming a plastic film provided with a printing layer and an overcoat layer, and laminating the obtained plastic film on the outer surface of the can body member. In the latter case (2),
Since the printing layer and the plastic film with the overcoat layer are laminated on the outer surface of the can body member by thermocompression bonding,
Overcoat layers, as well as plastic films and printing layers, are exposed to higher temperatures as compared to using adhesives.

Therefore, the printing layer is formed on one surface of the plastic film so that the overcoat layer can withstand the high temperature when the plastic film with the printing layer and the overcoat layer is laminated on the outer surface of the can body member. After that, when the overcoat layer is provided on the printed layer, it is preferable to sufficiently heat and cure the overcoat layer. If the overcoat layer is not sufficiently heated and cured, the printing layer and the overcoat layer are thermally deteriorated by the heat due to thermocompression bonding when laminating the plastic film with the printing layer and the overcoat layer on the member for the body of the can, The gloss changes and the color tone changes before and after stacking.

Further, when the overcoat layer of the plastic film with the printing layer and the overcoat layer is excessively hardened, the plastic film with the printing layer and the overcoat layer is attempted to be laminated on the can body member by thermocompression bonding. At this time, the adhesion between the overcoat layer and the plastic film is destroyed, and the overcoat layer may be transferred to the thermocompression bonding roll side used for thermocompression bonding. Therefore, from the viewpoint of preventing the transfer of the overcoat layer at the time of lamination, it is required that the overcoat layer itself is sufficiently cured before being laminated on the can body member.

By the way, when a bottomed cylindrical can body of a two-piece can is obtained by the method (2), when a plastic film with a printing layer and an overcoat layer is laminated on a can body member, A portion (lap portion) where the overcoat layer and the plastic film overlap is formed. The wrap part is from the outside to the inside (overcoat layer /
The structure is (printing layer / plastic film) / (overcoat layer / printing layer / plastic film). Further, in the two-piece can, after the bottomed cylinder in which the can body and the can bottom are integrated is formed, and before the lid member is attached, various processes for shrinking the opening end of the tubular part (can body part) ( Neck-in processing, flange processing, etc.) are performed.

Therefore, in the case of the above (2), since various processing is performed on the lap portion which occurs after the coating of the can body portion, each layer is required to have a tighter adhesion than the case of the above (1). It In order to secure the adhesion after various processing in the wrap portion, the overcoat layer located at the laminating interface of the wrap portion and the plastic film should be firmly adhered to each other by the heat when laminating on the can body member. is necessary. For that purpose, it is desired that the overcoat layer itself be dried to such an extent that it becomes tack-free before the lamination, while the curing reaction of the overcoat layer itself does not proceed so much. If the overcoat layer itself is excessively hardened before lamination, it is impossible to secure the adhesion after various processing in the lap portion after lamination.

That is, when the printing layer and the plastic film with the overcoat layer are laminated on the can body member, thermal deterioration of the overcoat layer is prevented and transfer of the overcoat layer to the hot roll side is prevented. From the viewpoint, it is required that the overcoat layer is sufficiently cured by heating when the plastic film with the printing layer and the overcoat layer is formed. On the other hand, in order to secure the adhesion after various processing in the lap portion after lamination, it is required that the overcoat layer before lamination is not cured as much as possible.

Further, the plastic film with the print layer and the overcoat layer is often wound and stored after production, and in this case, the overcoat layer comes into contact with the surface of the plastic film on the inner side. For that purpose, the overcoat layer generally contains a substance having a high slipperiness, and the substance having a high slipperiness in the overcoat layer may contaminate the surface of the non-overcoat layer of the plastic film during winding and storage. When the non-overcoat layer surface of the plastic film is contaminated, the adhesiveness (adhesion) between the printed layer and the plastic film with the overcoat layer and the can body member is impaired.
The "overprint" printing layer and the overcoat layer of the plastic film with the overcoat layer are non-staining and do not contaminate the facing and contacting surfaces, and the heat during thermocompression causes the gloss to change or transfer. Heat resistance that does not occur, adhesion that can withstand high-level processing applied to the lap portion after being laminated on the can body member, and slipperiness are required.

[0021]

SUMMARY OF THE INVENTION The present invention is directed to a resin composition for overcoating a plastic film having a "front printing" printing layer for coating the tubular portion (can body) of a plastic film-coated bottomed cylinder. An object of the present invention is to provide a resin composition capable of forming an overcoat layer having excellent non-staining property, heat resistance, adhesiveness, slipperiness, and the like.

[0022]

The first invention is a number average molecular weight of 1500 to 6000 and an epoxy equivalent of 800 to 500.
0 epoxy resin (A), number average molecular weight 900-130
0, an epoxy resin (B) having an epoxy equivalent of 180 to 500, a branched polyester resin (C) having a number average molecular weight of 5,000 to 15,000, an amino resin (D), a blocked or unblocked polyisocyanate compound (E), and the above. An overcoat resin composition for a plastic film (hereinafter, also referred to as OP varnish) containing a silicone compound (F) having a functional group capable of reacting with at least one of components (A) to (E). is there.

The second invention is a total of 100 weight of the epoxy resin (A), the epoxy resin (B), the polyester resin (C), the amino resin (D), and the blocked or unblocked polyisocyanate compound (E). %, Epoxy resin (A): 35 to 75% by weight, epoxy resin (B): 5 to 25% by weight, polyester resin (C): 10 to 30% by weight, and amino resin (D) + polyisocyanate compound (E):
The overcoat resin composition for a plastic film according to the first invention is characterized by containing 10 to 30% by weight, and the third invention is an epoxy resin (A),
0.001 to 100 parts by weight of the silicone compound (F) based on 100 parts by weight of the epoxy resin (B), the polyester resin (C), the amino resin (D), and the blocked or unblocked polyisocyanate compound (E). The overcoat resin composition for a plastic film according to the first or second invention, which contains 5 parts by weight.

A fourth invention is the overcoat resin composition for a plastic film according to any one of the first to third inventions, wherein the epoxy resin (B) is a cresol novolac type epoxy resin. .

A fifth invention is an overcoat layer (hereinafter referred to as O) formed from the overcoat resin composition for plastic film according to any one of the first to fourth inventions.
(Also referred to as P varnish layer), a printing layer, and a plastic film, which are laminated in that order, and a plastic film with an overcoat layer or the like.

A sixth aspect of the present invention is an overcoat layer according to the fifth aspect, wherein the outer surface of a bottomed cylindrical metal can body is covered with a plastic film on the outer surface of the can body of a plastic film-coated can (1). A plastic film-covered metal can (2), which is characterized in that plastic films with a contour are laminated by thermocompression bonding.

A seventh aspect of the present invention is that the fifth aspect of the present invention comprises:
A plastic film-covered metal plate, comprising the plastic film with an overcoat layer and the like according to the invention of claim 1 laminated by thermocompression bonding, and the eighth invention is the plastic film-covered metal according to the seventh invention. Plastic film coated metal can made of plate (3)
Is.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The overcoat composition (= OP varnish) of the present invention will be described below.

Epoxy Resin (A), Epoxy Resin (B) One of the features of the present invention is to use two kinds of epoxy resins having different number average molecular weights and epoxy equivalents. That is, it is necessary to use the specific epoxy resin (A) having a relatively large number average molecular weight and epoxy equivalent and the specific epoxy resin (B) having a relatively small number average molecular weight and epoxy equivalent. As will be described later, the cylindrical part (can body part) of the bottomed cylindrical plastic film-coated metal can body
When the outer surface is covered with a plastic film having an overcoat layer, necking is applied to the vicinity of the opening of the portion where the ends of the plastic film overlap each other after the film is laminated. )
If it is only used, the number of epoxy groups in the paint will be small, and the adhesiveness between the OP varnish layer of the plastic film and the plastic film in this overlap & neck processing part cannot be secured.

On the other hand, when only the epoxy resin (B) is used, the cohesive force of the cured coating film becomes weak because the number average molecular weight is small, and the scratch resistance, retort resistance, neck processability and the like of the OP varnish layer deteriorate. . Further, generally, an epoxy resin having a small number average molecular weight and an epoxy equivalent is liquid,
Many of them are solid but have a low melting point or softening point. Therefore, when only the epoxy resin (B) is used, OP
OP when winding plastic film with varnish layer
There is a problem that blocking between the varnish layer and the plastic film occurs. Furthermore, it is not sufficient to simply use an epoxy resin having a relatively large number average molecular weight and an epoxy equivalent and an epoxy resin having a relatively small number average molecular weight and an epoxy equivalent, respectively. Equivalent weight of epoxy resin (A),
It is necessary to use (B) together. For example, the number average molecular weight is 1500 to 6000 and the epoxy equivalent is 800 to 5000.
Epoxy resin (A) with a number average molecular weight of less than 900,
When the epoxy resin (B ') having an epoxy equivalent of less than 180 is used together, blocking between the OP varnish layer and the plastic film occurs and the plastic film cannot be rewound.

On the other hand, the number average molecular weight is 900 to 1300,
Epoxy resin (B) having an epoxy equivalent of 180 to 500
The number average molecular weight exceeds 6000 and the epoxy equivalent is 5
When the epoxy resin (A ') of more than 000 is used together, the number of epoxy groups occupying in the coating is reduced, resulting in poor adhesion between the OP varnish layer and the plastic film in the necked portion. Therefore, the epoxy resin (A) needs to have a number average molecular weight of 1500 to 6000 and an epoxy equivalent of 800 to 5000, and a number average molecular weight of 1500 to 3000 and an epoxy equivalent of 80.
It is preferably 0 to 2500. The epoxy resin (B) has a number average molecular weight of 900 to 1300,
It is necessary that the epoxy resin (B) has an epoxy equivalent of 180 to 500, and one having a melting point or a softening point of 60 ° C. or higher is preferable.

The epoxy resins (A) and (B) include bisphenol type epoxy resins, novolac type epoxy resins, and modified epoxy resins obtained by reacting various modifying agents with epoxy groups or hydroxyl groups in these epoxy resins, Examples thereof include a grafted epoxy resin obtained by graft-reacting various modifiers by a hydrogen abstraction reaction of a methylene bond.

Of the epoxy resins (A) and (B), the bisphenol type epoxy resin is, for example, a resin obtained by condensing epichlorohydrin and bisphenol to a predetermined molecular weight in the presence of a catalyst such as an alkali catalyst if necessary. In the presence of an alkali catalyst or the like, epichlorohydrin and bisphenol are condensed to form a low molecular weight epoxy resin, and any of the resins obtained by polyadding the low molecular weight epoxy resin and bisphenol It may be.

The bisphenol which is a raw material of the bisphenol type epoxy resin includes bis (4-hydroxyphenyl) methane [bisphenol F] and 1,1-bis (4
-Hiddleoxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane [bisphenol A],
2,2-bis (4-hydroxyphenyl) butane [bisphenol B], bis (4-hydroxyphenyl)-
1,1-isobutane, bis (4-hydroxy-tert)
-Butyl-phenyl) -2,2-propane, p- (4-
Hydroxyphenyl) phenol, oxybis (4-hydroxyphenyl), sulfonylbis (4-hydroxyphenyl), 4,4′-dihydroxybenzophenone,
Examples thereof include bis (2-hydroxynaphthyl) methane, and among them, bisphenol A and bisphenol F are preferably used. The bisphenols may be used alone or as a mixture of two or more.

Among such bisphenol type epoxy resins, commercially available products of the epoxy resin (A) are, for example,
Epicoat 1004 manufactured by Yuka Shell Epoxy Co., Ltd.
(Number average molecular weight (hereinafter referred to as Mn) = 1600, epoxy equivalent (hereinafter referred to as Ep) = 875 to 975), 1007 (Mn = 2900, Ep = 1750 to 220)
0), 1009 (Mn = 2900, Ep = 3750,
Ep = 2400-3300), 1010 (Mn = 55)
00, Ep = 3000-5000), manufactured by Asahi Kasei Epoxy Co., Ltd., Araldite AER6004 (Mn = 1).
600, Ep = 875-975), the same 6097 (Mn =
2900, Ep = 1750 to 2200), and 6099.
(Mn = 3750, Ep = 2400-3300) and the like. Among the bisphenol type epoxy resins, commercially available products of the epoxy resin (B) include Epicoat 1001 (Mn = 9) manufactured by Yuka Shell Epoxy Co., Ltd.
00, Ep = 450-500), Asahi Kasei Epoxy Co., Ltd.
AER6001 (Mn = 900, Ep = 450)
Up to 500).

Among the epoxy resins (A) and (B), examples of the novolac type epoxy resin include phenol novolac type epoxy resin, cresol novolac type epoxy resin, brominated epoxy resin, and many epoxy groups in the molecule. Various novolac type epoxy resins such as polyfunctional glycidyl ether resin having As the epoxy resin (B), a novolac type epoxy resin is preferable, and among them, a cresol novolac type epoxy resin is preferable, and further, a melting point or a softening point is 60 ° C. or higher from the viewpoint of hardness, scratch resistance, blocking resistance, etc. of the OP varnish. Are preferred.

Among the phenol novolac type epoxy resins, the commercially available epoxy resin (B) is as follows.
For example, XD-7855 (M manufactured by Dow Chemical Co., Ltd.
n = 1100, Ep = about 200), and the like. Among the cresol novolac type epoxy resins, as a commercially available product of the epoxy resin (B), for example, ECN-1273 (Mn = manufactured by Asahi Kasei Epoxy Co., Ltd.) is used. About 1040, E
p = 217), ECN-1299 (Mn = about 118)
0, Ep = 219), and the like.

Polyester Resin (C) The polyester resin (C) used in the present invention is a branched polyester resin having a number average molecular weight of 5,000 to 15,000. Preferably the number average molecular weight is 10,000 to 1500
The range is 0. When a polyester resin having a number average molecular weight of less than 5000 is used, the adhesion between the OP varnish layer after the retort treatment and a plastic film such as a PET film decreases. On the other hand, when a polyester resin having a number average molecular weight of more than 15,000 is used, the compatibility with the epoxy resin (A) decreases, so that the resin precipitates in the paint with the passage of time. Even if the polyester resin has a number average molecular weight within the above range, if a linear polyester resin is used instead of a branched polyester resin, the retort-treated OP varnish layer and a plastic film such as a PET film are Adhesion cannot be secured. The polyester resin (C) used in the present invention has a glass transition temperature of 40 to 130 ° C., preferably 60 to 130 ° C., the hardness of the OP varnish layer, scratch resistance, blocking resistance, etc. From the point of view, it is preferable.

The "straight chain type" polyester resin as referred to in the present invention is a polyester resin synthesized by using only the bifunctional component among the constituent components of the polyester resin described below, and is referred to as a "branched type" polyester resin. Is a polyester resin synthesized by using a bifunctional component and a trifunctional or higher functional component in combination.

The polyester resin (C) is obtained by subjecting a polybasic acid component and a polyhydric alcohol component to an esterification reaction, and as described above, a trifunctional or higher functional component may be used as at least one component. Examples of the polybasic acid component include phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic acid, fumaric acid, adipic acid, azelaic acid, sebacic acid, dodecanenic acid, maleic anhydride. , At least one dibasic acid selected from itaconic acid, dimer acid, and lower alkyl ester compounds of these acids are mainly used, and if necessary, benzoic acid, crotonic acid,
A monobasic acid such as p-t-butylbenzoic acid, a tribasic or higher polybasic acid such as trimellitic anhydride, methylcyclohexene tricarboxylic acid, and pyromellitic dianhydride are used in combination. As the polyhydric alcohol component, for example, ethylene glycol, diethylene glycol, propylene glycol,
1,4-butanediol, neopentyl glycol, 3
-Methylpentanediol, 1,4-hexanediol, 1,6-hexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc. Further, a trihydric or higher polyhydric alcohol such as glycerin, trimethylolethane, trimethylolpropane and pentaerythritol can be used in combination, if necessary. These polyhydric alcohols can be used alone or in admixture of two or more. The esterification or transesterification reaction of both components can be performed by a method known per se, for example, by polycondensing the former polybasic acid component and the polyhydric alcohol component at a temperature of about 180 to 250 ° C. be able to.

After obtaining a polyester having a hydroxyl group from the polybasic acid component and the polyhydric alcohol component, maleic acid, maleic anhydride, phthalic anhydride, trimellitic anhydride and the like are added to the hydroxyl group of the polyester. It may be a polyester resin in which a carboxyl group is introduced into the resin by reacting with a basic acid.

Commercially available products of the branched polyester (C) used in the present invention are, for example, Toyobo Co., Ltd.
Byron PCR-926 (Mn = 12000-1)
4000, Tg = 65 ° C.), Unitika KK-made Elitel UF-3300 (Mn = 8000, Tg = 45 ° C.)
And so on. Moreover, as a commercially available product of the linear polyester resin, for example, Byron 300 (Mn = 22,000 to 25,000, Tg = 10) manufactured by Toyobo Co., Ltd. is used.
℃), the same Vylon 200 (Mn = 15000-2000)
0, Tg = 67 ° C.), Vylon GK250 (Mn = 1)
2000-14000, Tg = 60 ° C), byron 2
40 (Mn = 7000 to 14000, Tg = 60 ° C.),
Byron 220 (Mn = 2000-3000, Tg =
53 ° C.), Elitel UF-320 manufactured by Unitika Ltd.
1 (Mn = 20,000, Tg = 65 ° C.) and the like.

Amino Resin (D) The amino resin used in the present invention is a methylolated amino resin obtained by reacting an amino component such as urea, melamine, benzoguanamine, acetoguanamine, steroguanamine, spiroguanamine, dicyandiamide and an aldehyde. To be Examples of the aldehyde include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like. Further, the methylolated amino resin which is etherified with a suitable alcohol or glycol ether can also be used. Examples of the alcohol or glycol ether used for the etherification include methyl alcohol, ethyl alcohol, n-propyl alcohol, iso- Propyl alcohol, n-butyl alcohol, iso-butyl alcohol, 2-ethylbutanol, 2-ethylhexanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, propylene glycol monomethyl ether. , Propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol Isopropyl ether and the like. As an amino resin,
Of these, a methylolated melamine resin in which at least a part of the methyl group is alkyl etherified is preferable.

Blocked or unblocked polyiso
Cyanate compound (E) Another feature of the present invention is an epoxy resin (A),
A blocked or unblocked polyisocyanate compound (E) is used in combination with the amino resin (D) as a curing agent for (B) and the polyester resin (C). By using the blocked or non-blocked polyisocyanate compound (E) together, heat resistance that cannot be achieved by using the amino resin (D) alone,
It is possible to obtain a plastic film with a printing layer and an overcoat layer, which can satisfy both the processing adhesion of the lap portion. That is, without using the blocked or unblocked polyisocyanate compound (E), only the amino resin (D) is used, and the curing reaction of the overcoat layer itself does not proceed so much at a relatively low temperature and a short time (170-
When the overcoat layer is formed under the condition of being lightly dried at 200 ° C. for about 5 to 15 seconds, the process adhesion of the lap portion can be secured.

However, since the curing of the overcoat layer before laminating the plastic film with the printing layer and the overcoat layer on the can body member under high temperature pressure (by thermocompression bonding) is insufficient, In contrast, after lamination, the gloss of the overcoat layer is significantly reduced. If the curing of the overcoat layer before lamination is further insufficient, the overcoat layer is transferred to the thermocompression bonding roll during thermocompression bonding.

On the other hand, a blocked or non-blocked polyisocyanate compound (E) is used in combination, and similarly to the above, at a relatively low temperature and a short time (170 to 200 ° C., 5 to 15).
When forming an overcoat layer under the conditions of
Since the blocked or unblocked polyisocyanate compound (E) is more reactive than the amino resin (D), the overcoat layer is appropriately cured. Therefore, the plastic film with the print layer and the overcoat layer is less likely to be damaged by the heat when the can body member is laminated under high temperature pressure (by thermocompression bonding). Further, under the above-mentioned conditions, the overcoat layer is not adequately cured, so that the processing adhesion in the lap portion is not impaired.

Examples of the unblocked polyisocyanate compound used in the present invention include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate, cycloaliphatic diisocyanates such as hydrogenated xylylene diisocyanate and isophorone diisocyanate, and trisulfate. Aromatic diisocyanates such as diisocyanate and 4,4′-diphenylmethane diisocyanate, triphenylmethane-4,
4 ', 4 "-triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 4,4'-dimethyldiphenylmethane-2,
It is an organic polyisocyanate itself such as a polyisocyanate compound having three or more isocyanate groups such as 2 ′, 5,5′-tetraisocyanate, or an adduct of each of these organic polyisocyanates with a polyhydric alcohol (so-called Examples thereof include adducts), adducts of each of these organic polyisocyanates with water (so-called biuret forms), and cyclized polymers of the above-mentioned organic polyisocyanates (so-called isocyanurates). A biuret body and an isocyanurate body of methylene diisocyanate are preferable.

Examples of commercially available products of the unblocked polyisocyanate compound (E) include Duranate 24A70PX (hexamethylene diisocyanate (hereinafter referred to as HDI) biuret form) and Duranate TPA-100 (manufactured by Asahi Kasei Corporation). HDI isocyanurate), the same duranate P-301-75E (HDI adduct), and the like.

The blocked polyisocyanate compound is obtained by blocking the isocyanate group of the above-mentioned non-blocked polyisocyanate compound with a blocking agent, and the blocking agent includes phenols such as phenol, cresol and xylenol, and ε. -Caprolactam, delta-valerolactam, gamma-butyrolactam, beta-
Lactams such as propiolactam, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol,
alcoholic systems such as tert-butyl alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, benzyl alcohol, formamidoxime, acetaldoxime, acetoxime, methylethylketoxime,
Examples thereof include oxime-based blocking agents such as diacetyl monooxime, benzophenone oxime, and cyclohexane oxime, and active methylene-based blocking agents such as diethyl malonate, ethyl acetoacetate, methyl acetoacetate, and acetylacetone. Of these, oxime-based blocking agents are preferably used.

Examples of commercial products of the blocked polyisocyanate compound include Coronate 2515 (a block of isocyanurate of HDI) and Coronate 2507 (HD) manufactured by Nippon Polyurethane Industry Co., Ltd.
I blocked isocyanurate), Coronate 2513 (blocked HDI isocyanurate), and the like.

The overcoat resin composition of the present invention reacts with at least one of the above-mentioned epoxy resins (A), (B), polyester resin (C), amino resin (D) and polyisocyanate compound (E). It is important to further contain a silicone compound (F) having a functional group to be obtained. That is, since the overcoat resin composition of the present invention is used for coating the outer surface of the can body member, it imparts slipperiness in order to prevent damage to the can body or improve transportability. It is necessary to contain a substance. Examples of the substance that imparts slipperiness include various silicone compounds, fluorine-containing compounds, polyolefin waxes such as polyethylene and polypropylene, and other waxes.
Silicone compounds are preferred.

By the way, the overcoat resin composition for a plastic film of the present invention can be directly applied to a bottomed cylindrical plastic film-coated metal can, but as will be described later, it is applied to one surface of the plastic film. The overcoat resin composition of the present invention is applied on the provided printing layer to form a plastic film with an overcoat layer, and a cylindrical portion of a bottomed cylindrical plastic film-coated metal can body or a can body portion is formed. The plastic film with the overcoat layer can be laminated on a can body member such as a metal plate for use in a can. When the method of laminating the film on the can body member is adopted as described above, after forming the overcoat layer, the overcoated plastic film may be once wound into a coil and stored. When wound into a coil, the overcoat layer overlaps the plastic film. At this time, if a substance that is rich in slipperiness contained in the overcoat layer migrates and adheres to the surface of the plastic film that is in contact with it, the adhesion of the plastic film with the overcoat layer is hindered when it is laminated on the can body member. To do.

Furthermore, a bottomed cylindrical plastic film-coated metal can body or a cylindrical portion of the bottomed cylindrical metal can body (can body)
When the outside of the above is covered with a plastic film with an overcoat layer, the ends of the plastic film are covered so that they overlap each other. In the overlap part, the O of the plastic film located on the lower side
The P varnish layer and the plastic film surface located on the upper side are superposed. When the slip agent blended in the overcoat resin composition easily separates from the OP varnish, the adhesion between the OP varnish layer and the plastic film in the overlap portion is hindered.

Therefore, the silicone compound which imparts slipperiness to the overcoat layer does not migrate to the plastic film, and the above-mentioned epoxy resins (A), (B), polyester resin (C), which form the overcoat layer,
It is important to have a functional group capable of reacting with at least one of the amino resin (D) and the polyisocyanate compound (E). As the functional group capable of reacting with (A) to (E),
Examples thereof include a hydroxyl group, an amino group, a carboxyl group and an epoxy group, and among them, a hydroxyl group is preferable. Examples of the hydroxyl group-containing silicone compound include reactive silicone oils obtained by modifying side chains, one end, both ends or side chains and both ends of dimethylpolysiloxane with carbinol. Examples of commercially available products of the hydroxyl group-containing silicone compound include terminal hydroxyl group polyester modified siloxanes X-24-8300, X-24-8301, and X- manufactured by Shin-Etsu Chemical Co., Ltd.
22-170DX, X-22-176DX, X-22-
176F etc. can be mentioned. Both ends X-22-
160AS, KF-6001, KF-6002, KF-
6003 etc. can be mentioned. Moreover, as a thing which has a hydroxyl group in a side chain, X-22-4015 etc. are mentioned. A silicone compound having no functional group capable of reacting with (A) to (E), for example, X manufactured by Shin-Etsu Silicone Co., Ltd.
22-4272, X22-4952, X24-8310
If it contains, etc., it is possible to obtain an overcoat layer rich in slipperiness, but these silicone compounds contained in the overcoat layer are transferred to a plastic film which is in contact during winding and storage, and when it is contaminated, The adhesion between the plastic film with an overcoat and the can body member and the adhesion at the overlap portion are impaired.

The overcoat resin composition for a plastic film of the present invention comprises an epoxy resin (A), an epoxy resin (B), a polyester resin (C), an amino resin (D), and a blocked or unblocked polyisocyanate compound. Epoxy resin (A): 35 to 75% by weight, epoxy resin (B): 5 to 25% by weight, polyester resin (C): 1 in the total 100% by weight of (E).
It is preferable to contain 0 to 30% by weight and amino resin (D) + polyisocyanate compound (E): 10 to 30% by weight. When the outer surface of the cylindrical portion (can body portion) of the bottomed cylindrical plastic film-coated metal can is covered with the plastic film with an overcoat layer of the present invention described below, after laminating the films, the ends of the plastic film overlap each other. Neck processing is applied to the vicinity of the opening in the wrapped portion, but when the epoxy resin (B) is less than 5% by weight, the number of epoxy groups in the paint decreases, and this "overlap & neck processing" is performed. The adhesiveness between the OP varnish layer and the plastic film in the area "" tends to decrease. On the other hand, when the epoxy resin (B) exceeds 25% by weight, the amount of low molecular weight epoxy resin increases, so that the OP varnish layer tends to have poor scratch resistance, retort resistance, neck processability, and the like.

When the polyester resin (C) is less than 10% by weight, the adhesion between the plastic film and the OP varnish layer is deteriorated. When the polyester resin (C) exceeds 30% by weight, the epoxy resin (A ) And (B) occupy less proportion, the adhesiveness between the OP varnish layer and the plastic film in the "overlap & neck processing" portion decreases.

When the amount of the amino resin (D) + polyisocyanate compound (E) is less than 10% by weight, the curability of the coating film becomes insufficient and the scratch resistance, retort resistance, blocking property, etc. are deteriorated. On the other hand, when the amount of the amino resin (D) + polyisocyanate compound (E) exceeds 30% by weight, the cured coating film (OP varnish layer) becomes brittle and the neck processability deteriorates. Further, the polyisocyanate compound (E) is
2 to 15% by weight in total 100% by weight of (A) to (E)
Is preferably blended. When the polyisocyanate compound (E) is less than 2% by weight, the polyisocyanate compound (E) is treated with an amino resin (D).
The effect of combined use with can not be expected so much, and the curing tends to be insufficient when the overcoat layer is dried. As a result, when the printed layer and the plastic film with the overcoat layer are thermocompression-bonded to the bottomed cylindrical body member of the can, the overcoat layer is easily deteriorated by heat and gloss is deteriorated. It is blocked by a roll, and the overcoat layer is peeled off from the underlying printing layer or plastic film. On the other hand, the polyisocyanate compound (E) is 15
When the content is more than 5% by weight, it tends to react with many epoxy groups in the epoxy compound (A) and the epoxy compound (B) to crush the epoxy groups when the overcoat layer is dried, resulting in "overlap & neck processing". OP in the department
The adhesion between the varnish layer and the plastic film tends to decrease.

The overcoat resin composition of the present invention reacts with at least one of the above-mentioned epoxy resins (A), (B), polyester resin (C), amino resin (D) and polyisocyanate compound (E). It is important to contain a silicone compound (F) having a functional group to be obtained,
(A)-(E) to 100 parts by weight in total, (A)-
The silicone compound (F) having a functional group capable of reacting with (E) is preferably used in an amount of 0.001 to 5 parts by weight. It is preferably in the range of 0.1 to 3 parts by weight from the viewpoint of slipperiness and adhesion between the OP varnish layer and the plastic film in the overlap portion of the plastic film.

Further, the overcoat composition for a plastic film of the present invention comprises an epoxy resin (A), an epoxy resin (B), a polyester resin (C), an amino resin (D), a blocked or unblocked polyisocyanate compound. In addition to (E) and the reactive silicone compound (F), a curing catalyst, an organic solvent, a matting agent, a defoaming agent, an antistatic agent, etc. can be contained, if necessary.

As the curing catalyst, amino resin (D)
Is a low molecular weight alkyl etherified amino resin, a sulfonic acid compound or an amine neutralized product of a sulfonic acid compound is preferably used. Typical examples of the sulfonic acid compound include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, phosphoric acid and the like. The amine in the amine-neutralized product of the sulfonic acid compound may be a primary amine, a secondary amine, or a tertiary amine. When the polyisocyanate compound is a blocked polyisocyanate compound, it is preferable to use a curing catalyst that promotes dissociation of the blocking agent of the blocked polyisocyanate compound, for example,
Tin octylate, dibutyltin di (2-ethylhexanoate), dioctyltin di (2-ethylhexanoate),
Organometallic catalysts such as dibutyltin dilaurate, dibutyltin oxide, dioctyltin oxide and lead 2-ethylhexanoate can be preferably used.

As the delusterant, silica, polyethylene wax, silicone powder and the like generally used for paints and inks are preferably used. As the defoaming agent, those generally used for paints and inks can be used as they are.

Plastic film with overcoat layer
The plastic film with an overcoat layer according to the present invention is a plastic film with an overcoat layer formed by sequentially laminating an overcoat layer formed from the above overcoat resin composition, a printing layer, and a plastic film, and a so-called “table Imprint ”A plastic film with a print layer and an overcoat layer. Such a plastic film with an overcoat layer is formed by printing and drying ink on one surface of the plastic film to form a printing layer, and the overcoat resin crude composition is applied onto the printing layer by a roll coater or a gravure coater. With a coating machine such as the above, the coating is usually applied so that the dry film thickness is about 0.5 to 10 μm, and then the ambient temperature is usually 170 to 20.
It can be formed by heating and drying for about 5 to 30 seconds under the condition of about 0 ° C.

As the plastic film used for the plastic film with the overcoat layer, any plastic film having heat resistance and strength can be used. Among them, polyester film, especially 75 to 100% of the ester repeating unit is ethylene terephthalate. Those composed of units are preferred. Examples of the ester unit other than the ethylene terephthalate unit include ester units such as phthalic acid, isophthalic acid, succinic acid and adipic acid. The overcoat resin composition of the present invention,
It has sufficient adhesion to a plastic film that has not been subjected to special corona discharge treatment, but in order to improve the adhesion with the overcoat layer and the printing layer, the surface of the plastic film is treated with corona discharge treatment. It is preferable to use a product that has been subjected to. The thickness of the plastic film is not particularly limited, but usually, a thickness of about 5 to 30 μm can be preferably used.

As the ink used for forming the printing layer in the plastic film with the overcoat layer, the printing ink known per se used for printing the packaging film can be used without particular limitation, and the printing ink application method is also applicable. It can be performed by a method similar to the printing of the packaging film.
The type of printing ink is preferably a cross-linking ink, and examples thereof include urethane resin, polyester resin, acrylic resin, and alkyd resin.

The obtained plastic film with an overcoat layer is used for various packaging materials (plastic film that covers the outer surface of the cylindrical portion of a cylindrical plastic film-covered metal can body with a bottom, cylindrical metal can body with a bottom) immediately after production. It can be attached to the outer surface of the cylindrical part of, or the metal plate that constitutes the so-called can body of a three-piece can, etc., but it is stored in a coiled form after being manufactured and then attached to the above various packaging materials. It can also be done. If stored
Since the overcoat layer and the plastic film overlap each other during storage, blocking resistance between these layers is required. If the blocking resistance is poor, there is a problem that the coil cannot be unwound, or even if the coil can be unwound, a part of the overcoat layer adheres to the surface of the plastic film.

Plastic film-coated metal can (2) Next, the plastic film-coated metal can (2) of the present invention
Will be described. The plastic film-coated metal can (2) of the present invention is the plastic film-coated metal can (1) in which the outer surface of a bottomed cylindrical metal can body is previously coated with the plastic film. The plastic film is laminated on the outer surface of the can body by thermocompression bonding. The plastic film with the overcoat layer is laminated on the outer surface of the can body of the plastic film-coated metal can (1) by thermocompression bonding so that the plastic film with the overcoat layer does not deteriorate, and the plastic film with the overcoat layer and the plastic The film-coated metal can (1) is not particularly limited as long as it is sufficiently adhered to the plastic film on the outer surface of the can body and the plastic film-coated metal can (2) having a good appearance is obtained.
As the laminating conditions, for example, a method of using a heating roll or a method of preheating the plastic film-coated metal can (1) in advance is used to heat the surface temperature of the plastic film-coated metal can (1) to about 150 to 200 ° C. Then, a method in which the plastic film on the outer surface of the can of the plastic film-covered metal can (1) and the plastic film with the overcoat layer are thermocompression-bonded for a short time (usually about 2 seconds or less) and laminated can be mentioned. . Lightly stack the plastic film with the overcoat layer on the outer surface of the plastic film-covered metal can (1) under pressure and heat, then apply the paint on the inner surface of the can and use the heat when baking and curing it. Then, the curing reaction of the overcoat layer can further proceed.

The bottomed cylindrical plastic film-coated metal can (1) has a size of one can from a plastic film-coated metal plate obtained by laminating plastic films on at least one surface of various metal plates according to a conventional method. The plate is cut out, and this one can of plastic film-coated metal plate is formed into a cylindrical shape with a bottom so that the plastic film coating layer is on the outside.

Examples of the metal plate used for the bottomed cylindrical plastic film-coated metal plate (1) include hot-rolled steel plate, cold-rolled steel plate, hot-dip zinc alloy, plated steel plate, galvanized steel plate, and iron-zinc alloy plating. Steel plate, zinc-aluminum alloy-plated steel plate, nickel-zinc alloy-plated steel plate, nickel-tin alloy-plated steel plate, tin plate, chrome-plated steel plate, aluminum-plated steel plate, turn-plated steel plate, nickel-plated steel plate, stainless steel, tin-free steel, aluminum plate , Copper plates, titanium plates, and other metal materials, these metal materials are subjected to chemical conversion treatment, for example, phosphate treatment, chromate treatment, composite oxide film treatment, etc., these metal materials or chemical conversion treatment metal plates Primer coated metal plate with a primer layer such as white coat on the surface of the How painted metal plate can be mentioned.

The plastic film used for the bottomed cylindrical plastic film-coated metal can (1) is as follows:
Cellophane, nylon, polypropylene, polyethylene,
Polyethylene terephthalate, polyvinyl chloride, polystyrene, polyvinyl alcohol, polyvinylidene fluoride, polycarbonate, polytetrafluoroethylene,
A film made of an ethylene / acrylic acid copolymer, polysulfone, or a composite material of these plastics can be used.

Plastic film-covered metal plate and plate
Rust film-coated metal can (3) Next, the plastic film-coated metal plate and the plastic film-coated metal can (3) of the present invention will be described. The plastic film-covered metal plate of the present invention is obtained by laminating the above-mentioned plastic film with an overcoat layer on one surface of the metal plate by thermocompression bonding. Examples of the metal plate used include the same metal plates as those used for obtaining the plastic film-coated metal can (1). The conditions for laminating the metal plate and the plastic film with the overcoat layer are the same as those for laminating the plastic film on the outer surface of the can body of the plastic film-coated metal can (1) and the plastic film with the overcoat layer by thermocompression bonding. Is. The plastic film-covered metal plate of the present invention is particularly preferably used for the plastic film-covered metal can (3) as described below. In addition, it can be used for metal lids such as caps, laminated tubes, magic bottles, and refrigerator outer surfaces. It can also be applied to the exterior of household appliances.

In the plastic film-coated metal can (3) of the present invention, the plastic film-coated metal plate obtained as described above is rolled into a cylindrical shape so that the overcoat layer is on the outside, and both ends are adhered. The tubular member is obtained by welding or the like, and the lid member and the bottom member are attached to the opening of the tubular member.

The tubular member has a metal plate and an overcoat layer since it is applied with a repair paint or a paint on the inner surface of the can before or after attaching the lid member or the bottom member. It is also possible to lightly laminate (thermocompression-bond) with a plastic film, and utilize the heat at the time of heating and curing these coating materials to proceed the curing reaction of the overcoat layer of the plastic film-covered metal plate.

[0073]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the examples. In addition, "part" and "%" will be used unless otherwise specified.
Are based on weight.

Production Example 1 of polyester resin (C1)
Manufacturing 4-neck flask with 445.7 parts of dimethyl terephthalic acid,
71.2 parts of ethylene glycol, 192.1 parts of propylene glycol, 41.0 parts of trimethylolpropane and 0.15 part of zinc acetate are charged and the temperature is raised to 180 ° C. Gradually raise the temperature to 220 ° C from the start of the demethanol reaction until the theoretical amount of demethanol reaches 95% or more.
Continue the reaction for 3-4 hours. Theoretical demethanol amount is 95%
When the temperature exceeds the above, the temperature is lowered to 200 ° C. and tetra-n-
Add 0.0075 parts of butyl titanate and raise to 220 ° C. When the temperature reached 220 ° C, the reaction system was gradually decompressed, and the temperature was gradually reduced to 240 mm under reduced pressure of 5 mmHg or less.
Up to ℃, and perform the glycol removal reaction for 3-4 hours,
When the number average molecular weight reached 6000, the reaction was stopped to obtain a branched polyester resin (C1). The glass transition point of the obtained polyester resin (C1) was 65 ° C.

Production Example 2 Production of polyester resin (C2)
In a four-necked flask made of dimethyl terephthalic acid 400 parts, propylene glycol 305 parts, ethylene glycol 42
Parts, neopentyl glycol 32 parts, and magnesium acetate 0.18 parts, tetra-n-butyl titanate 0.2.
9 parts was added and the temperature was gradually raised, and the reaction was continued for 4 hours until the reaction temperature reached 220 ° C. Next, 0.14 parts of triphenyl phosphite was added to raise the reaction temperature to 250 ° C., and the reaction system was gradually depressurized and then reacted for 4 hours under a reduced pressure of 0.5 mmHg or less to obtain a linear polyester resin (C
2) was obtained. Obtained linear polyester resin (C2)
Has a number average molecular weight of 17,000 and a glass transition point of 72 ° C.
Met.

Production Example 3 Production of polyester resin (C3)
398.4 parts of isophthalic acid forming a four-necked flask, 75.9 parts of ethylene glycol, neopentyl glycol 12
7.3 parts, trimelliol propane 38.6 parts, and zinc acetate 0.012 parts are charged, and the temperature is raised to 200 ° C. After the dehydration reaction started, the temperature was gradually raised to 240 ° C and the reaction was continued for about 4 hours. When the oxidation became 5 or less, 200 ° C
Reduce the temperature to and then start depressurizing. A branched polyester resin (C3) was obtained by reacting for about 30 minutes under a reduced pressure of 2 mmHg or less. The number average molecular weight of the obtained branched polyester resin (C3) was 1300, and the glass transition point thereof was 60 ° C.

[0077]

Example 1 "Epicoat 1004" (Mn = 160
0, Ep = 875-975) 50 parts, “ECN-127
3 "(Mn = about 1040, Ep = 217) 10 parts," polyester resin C1 "obtained in Production Example 1 (Mn = 60)
00, Tg = 65 ° C) 20 parts, "Cymel 303" 15
Parts, 5 parts of "Duranate 24A70PX", 1 part of "Shin-Etsu Silicone X24-8300", and 1 part of "paratoluenesulfonic acid" are dissolved in a mixed solvent (MEK / methyl propylene glycol / ethyl acetate = 80/10/10). Nonvolatile content 15%, viscosity 10 seconds (Ford Cup # 4,
An overcoat resin composition of 25 ° C.) was prepared.

[Example 2] [Examples 2 to 8] and [Comparative Examples 1 to 1]
2]: Overcoat resin composition In the same manner as in Example 1, the overcoat resin compositions shown in Tables 1 and 2 were prepared.

[Examples 9 to 16] and [Comparative Examples 13 to 2]
4]: A plastic film with an overcoat layer, etc. A polyurethane resin-based ink layer is provided on one side of a polyethylene terephthalate film (PET film) "Melinex 850" (thickness 15 μm) manufactured by ICC Japan Co., Ltd. The overcoat resin composition prepared in each of Examples and Comparative Examples was coated on the printed layer so that the dry film thickness was 1 μm, and the ambient temperature was adjusted to 12 by a dryer.
After drying at 0 ° C for 8 seconds, overcoat layer / printing layer /
A plastic film with an overcoat layer and the like was obtained by sequentially laminating plastic films.

[Examples 17-24] and [Comparative Examples 25-
36]: Laminating plastic film with overcoat layer on plastic film-covered metal plate Prepare two plastic films with overcoat layer etc. obtained in each of Examples and Comparative Examples, and the non-overcoat layer surface of one film is Two films are overlapped with a width of 2-3 mm so that they are in contact with the overcoat layer of the other film, and one side of a tin-free steel metal plate with polyethylene terephthalate film on both sides is overlapped and set at 200 ° C. The resulting laminator was thermocompression bonded under a pressure of 5 kg / cm ² and a speed of 1 m / min to obtain a laminate of a plastic film with an overcoat layer / a plastic film-coated metal plate.

Evaluation method 1. <Blocking resistance>: Examples 9 to 16 and Comparative Example 1
2 to 22 each prepared plastic film with an overcoat layer, etc., and superimposing the overcoat layer surface and the non-overcoat layer surface of each film under the conditions of a temperature of 50 ° C. and a pressure of 5 kg / cm ² . After heat-pressing for 2 hours, it was discharged to room temperature. After cooling to room temperature, the laminated films were peeled off by hand, and the peeling state of the overcoat layer and the resistance when peeling the overcoat layer surface and the non-overcoat layer surface were evaluated. ⊚: There is no peeling of the overcoat layer, and the resistance when peeled by hand is smaller than the resistance when peeled between PET films. ◯: There is no peeling of the overcoat layer, and the resistance feeling when peeled by hand is the same as the resistance feeling when peeling PET films from each other. Δ: The resistance when peeled by hand is larger than the resistance when peeled between PET films, but the overcoat layer is not peeled at all. X: A part or all of the overcoat layer is peeled off from the PET film and attached to the contacting non-overcoat layer surface.

2. <Backside stain resistance>: The surface of the overcoat layer of the plastic film with an overcoat layer obtained in Examples 9 to 16 and Comparative Examples 13 to 24 and the corona discharge treated surface of the PET film (surface tension: 45 dune / cm or more). Were superposed and pressure-bonded by the same method as in the blocking resistance test. After cooling to room temperature and peeling the laminated films by hand, the surface tension of the corona discharge treated surface of the PET film that was pressure-bonded to the surface of the peeled PET film overcoat layer was measured by Wako Pure Chemical Industries, Ltd. ,
Wet index standard solution was used for measurement. ⊚: Surface tension is 45 dyne / cm or more ◯: Surface tension is 38 to 45 dyne / cm Δ: Surface tension is 33 to 37 dyne / cm ×: Surface tension is 33 dyne / cm or less

3. <Heat deterioration during lamination>: Example 9
.About.16, the plastic films with overcoat layers obtained in Comparative Examples 13 to 24 were laminated with one side of a tin-free steel metal plate having polyethylene terephthalate film stuck on both sides with the non-overcoat layer side facing down, and 200.degree. 5k pressure with laminator set to
Thermocompression bonding was performed under the conditions of g / cm ² and speed of 1 m / min, and the degree of thermal deterioration of the overcoat layer and the printing layer was evaluated according to the following criteria. ⊚: There is no decrease in gloss. ◯: A decrease in gloss of less than 5% is recognized at 60 ° gloss. Δ: A gloss reduction of 5% to 10% is recognized at 60 ° gloss. X: A gloss reduction of 10% or more is recognized at 60 ° gloss.

4. <Adhesion to PET film>: on the overcoat layer surface (non-overlap portion) of the laminate of the plastic film with an overcoat layer / plastic film-coated metal plate obtained in Examples 17 to 24 and Comparative Examples 25 to 36. A cross-cut was made with a knife, a cellophane tape was brought into close contact with the cross-cut portion, and the degree of peeling of the overcoat layer from the PET film when the cellophane tape was rapidly peeled upward was evaluated according to the following criteria. A: No peeling of the overcoat layer is observed. ◯: Peeling of the overcoat layer is slightly observed,
The width is within 0.5 mm from the knife scratch. Δ: Peeling of the overcoat layer is considerably observed. X: Peeling of the overcoat layer is remarkably observed.

4. <Adhesion after hot water treatment after baking>:
The plastic film / plastic film-coated metal sheet laminate with an overcoat layer obtained in Examples 17 to 24 and Comparative Examples 25 to 36 was baked for 75 seconds in a dryer at an ambient temperature of 210 ° C. Then, after subjecting the laminated body after baking to hot water treatment in deionized water at 125 ° C. for 30 minutes, a cross cut is put in the non-overlap portion and the overlap portion of the overcoat layer, and an adhesion test is performed with cellophane tape. Adhesion between the overcoat layer and the PET film in the non-overlap portion and adhesion between the overcoat layer and the non-overcoat layer surface in the overlap portion were evaluated according to the following criteria. A: Overcoat layer and P in non-overlap area
There is no peeling between the ET films, and no peeling is observed between the overcoat layer and the non-overcoat layer surface in the overlap portion. O: Overcoat layer and P in non-overlap area
Peeling was slightly observed between the ET films or between the overcoat layer and the non-overcoat layer surface in the overlap portion, but 0.5 mm from the knife scratch
Is within the range of. Δ: Overcoat layer and P in non-overlap portion
Peeling is considerably observed between the ET films or between the overcoat layer and the non-overcoat layer surface in the overlap portion. ×: Overcoat layer and P in the non-overlap portion
Peeling is remarkably observed either between the ET films or between the overcoat layer and the non-overcoat layer surface in the overlap portion.

5. <Adhesiveness of Overlap Part and Processed Part After Baking>: The laminate of the plastic film with the overcoat layer / the plastic film-coated metal plate obtained in Examples 17 to 24 and Comparative Examples 25 to 36 was used at an ambient temperature of 210 ° C. Baked for 75 seconds. Then, the laminated body after baking is drawn into a cap shape having a diameter of 35 mm and a depth of 10 mm so that the overcoat layer side is the convex outer side and the overlapping portion is located substantially in the center of the convex portion. And then in deionized water 125
Hot water treatment was performed at 30 ° C. for 30 minutes, and the degree of peeling of the overlapped portion subjected to the drawing process was evaluated according to the following criteria. A: No peeling is observed on the circumference of the cap. ◯: Peeling is observed at one place on the circumference of the cap. Δ: Peeling is observed at 2-3 places on the circumference of the cap. X: Peeling is recognized at four or more places on the circumference of the cap.

6. <Dynamic friction coefficient after baking>: The laminate of the plastic film with an overcoat layer / the plastic film-coated metal plate obtained in Examples 17 to 24 and Comparative Examples 25 to 36 was dried at an ambient temperature of 210 ° C for 7 days.
Bake for 5 seconds. At 20 ° C., a weight of a steel ball three-point contact type load of 1 kg was set on the overcoat layer of the laminated body after baking using a slip tester, and the dynamic friction coefficient at a moving speed of 100 cm / min [friction resistance (g ) / 1000 (g)] was obtained and evaluated according to the following criteria. ◎: Dynamic friction coefficient is less than 0.08 ○: Dynamic friction coefficient is 0.08 or more and less than 0.10 △: Dynamic friction coefficient is 0.10 or more and less than 0.14 ×: Dynamic friction coefficient is 0.14 or more

7. <Scratch resistance after baking>: The laminate of the plastic film with an overcoat layer / the plastic film-coated metal plate obtained in Examples 17 to 24 and Comparative Examples 25 to 36 was dried at an ambient temperature of 210 ° C. for 7 hours.
Bake for 5 seconds. Load 1 using a Bowden friction tester
A weight of 00 g was placed on the overcoat layer of the laminated body of the plastic film / plastic film-coated metal plate with the overcoat layer of the laminated body after baking as described above, and 3
The degree of scratches on the surface of the overcoat layer when rubbing 0 times back and forth was evaluated according to the following criteria. A: Almost no scratch is observed. ◯: Slight scratches are recognized. Fairly scratches are observed. X: A scratch is recognized on the entire surface.

[0088]

[Table 1]

[0089]

[Table 2]

[0090]

The overcoat resin composition of the present invention comprises
It is suitable for forming a "front printing" printing layer and a plastic film with an overcoat layer, which are formed by sequentially laminating an overcoat layer / a printing layer / a plastic film. The "surface printing" printing layer and the plastic film with the overcoat layer, which are formed by using the overcoat resin composition of the present invention, are suitable for laminating on the can body member even though the curing of the overcoat layer is insufficient to some extent. Excellent heat resistance. Then, using the plastic film with the overcoat layer, a member for a can body (the outer surface of the cylindrical part (can body part) of a metal can body molded in a bottomed cylinder shape or a bottomed cylindrical shape) By coating the outer surface of the cylindrical part (can body part) of a plastic film-coated metal can body, or the metal plate in the case of a three-piece can, with a gravure printing method and the like on the outer surface of the can body part, which has a high-quality appearance. It is possible to impart sex. Further, the overcoat resin composition of the present invention,
It has excellent adhesion to the plastic film, and also to the overcoat layer and non-overcoat layer surface (that is, plastic film) in the overlap part, so necking or flanging near the opening of the can cylindrical part, or It does not peel off even if it is subjected to curling or the like and then subjected to hot water treatment (retort treatment). Further, the overcoat layer formed from the overcoat resin composition of the present invention has excellent slipperiness, but does not have back contamination by a silicone compound, etc., and impairs printability such as gravure printing. Adhesion between the plastic film with the overcoat layer and the outer surface of the cylindrical portion (can body portion) of the plastic film-covered metal can body formed into a cylindrical shape with a bottom is not hindered.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 163/04 C09D 163/04 167/00 167/00 175/04 175/04 183/04 183/04 / / B65D 25/36 B65D 25/36 F term (reference) 3E033 AA06 BA07 BA17 BA30 BB01 CA07 DA02 DD01 EA10 FA01 3E062 AA04 AC03 JA01 JA08 JB04 JC02 JD10 4F006 AA35 AB33 AB34 AB35 AB37 AB39 BA02 BA01 BA01 BA01 CA15 CA07 BA11 BA15 CA15 BA07 BA11 BA15 CA15 AK41A AK42 AK51A AK52A AK53A AL02A AL05A BA01 BA03 BA04 BA07 BA10A BA10B BA10D CC00A DA01 EH46 EH46A EJ17D EJ42D EJ65A GB16 GB23 HB31B NA07 DL16 NA02 GL03 DA162 NA02 DIA02 NA12 DIA02 DA162 DIA03 DA112 DA112 DA112

Claims (8)

[Claims] 1. An epoxy resin (A) having a number average molecular weight of 1500 to 6000 and an epoxy equivalent of 800 to 5000, a number average molecular weight of 900 to 1300, and an epoxy equivalent of 180 to 50.
0 epoxy resin (B), number average molecular weight 5,000 to 15
000 branched polyester resin (C), amino resin (D), blocked or unblocked polyisocyanate compound (E), and a functional group capable of reacting with at least one of the above components (A) to (E). An overcoat resin composition for a plastic film, which comprises the silicone compound (F). 2. An epoxy resin (A), an epoxy resin (B), a polyester resin (C), an amino resin (D),
And in a total of 100% by weight of the blocked or unblocked polyisocyanate compound (E), epoxy resin (A): 35 to 75% by weight, epoxy resin (B): 5 to 25% by weight, polyester resin (C) : 10 to 30% by weight, and amino resin (D) + polyisocyanate compound (E):
10. It contains 10 to 30% by weight.
The overcoat resin composition for a plastic film as described above. 3. An epoxy resin (A), an epoxy resin (B), a polyester resin (C), an amino resin (D),
And 0.001 to 5 parts by weight of the silicone compound (F) based on 100 parts by weight of the blocked or unblocked polyisocyanate compound (E) in total. Overcoat resin composition for plastic film. 4. The epoxy resin (B) is a cresol novolac type epoxy resin.
3. The overcoat resin composition for a plastic film according to any one of 3 to 3. 5. A printing layer and an overcoat layer formed from the overcoat resin composition for a plastic film according to claim 1 are sequentially laminated on one surface of the plastic film. A plastic film with a characteristic overcoat layer. 6. The non-coated plastic film with an overcoat layer according to claim 5, which is provided on the outer surface of the can body of a plastic film-coated can (1) in which the outer surface of a bottomed tubular metal can body is covered with a plastic film. A plastic film-coated metal can (2), characterized in that the overcoat layer surfaces are laminated by thermocompression bonding. 7. A plastic film-covered metal plate, characterized in that the non-overcoat layer surface of the plastic film with an overcoat layer according to claim 5 is laminated on one surface of the metal plate by thermocompression bonding. 8. A plastic film-covered metal can (3) comprising the plastic film-covered metal plate according to claim 7.