JP2002347168A - Laminated sheet and coated seamless can using the sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated sheet for manufacturing a can capable of reducing shaving-off of a film layer when the can is manufactured even though it contains pigment, having excellent corrosion resistance and hiding property due to increase of whiteness of the outer face, and in which print quality is improved, and a coated seamless can which is obtained by using this laminated sheet and has excellent impact resistance (dent resistance). SOLUTION: In this laminated sheet in which a resin film containing a surface resin layer (a) in which pigment content is 20 wt.% or less and a resin layer (b) in which the pigment content is 10-70 wt.% and is more than that of the surface resin layer (a) is laminated on a metal sheet, the resin layer (b) of the laminated sheet is a base layer, the value of birefringence (Δn) of a film part contacting to the metal sheet of the resin layer (b) is 0.1 or less and is the value of the birefringence of a film part on the front face side or less, provided that Δn=nm-nt, wherein nm is a reflective index in the maximum orientation direction of the film, and nt is the reflective index in a thickness direction of the film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated plate for cans and a coated seamless can using the laminated plate. Using a laminated plate for cans, which has reduced corrosion, excellent corrosion resistance, and excellent concealability due to an increase in whiteness of the outer surface, and improved printing quality, and The present invention relates to a coated seamless can excellent in dent resistance obtained by the above method.

[0002]

2. Description of the Related Art Conventionally, as a side seamless can (side seamless can), a metal material such as an aluminum plate, a tin plate or a tin-free steel plate is provided by at least one step between a drawing die and a punch. By drawing, a cup consisting of a body part having no side seam and a bottom part connected to the body part without a seam is formed, and then, if desired, an ironing punch and a die are formed on the body part. It is known that the body of the container is thinned by ironing between them.
Further, instead of ironing, thinning drawing, in which the side wall is thinned by bending and stretching at the curvature corner of the redrawing die, is already known (Japanese Patent Publication No. 56-501442).

As an organic coating method for a side seamless can, there is known a method of laminating a resin film on a metal material before molding in advance. Japanese Patent Publication No. 59-34580 discloses that a metal material is terephthalic acid. It is described that a laminate obtained by laminating a polyester film derived from and tetramethylene glycol is used.

[0004] It is also known to produce a colored seamless can in which a pigment is previously contained in a resin film coated on the outer surface.
6-16739 and 6-1 based on the applicant's proposal
Japanese Patent No. 6740 discloses a laminate of a clear polyester molecular orientation film layer / adhesive / surface treated steel sheet / adhesive / titanium dioxide-containing polyester molecular orientation film layer / printing ink layer / finish varnish layer from the inside to the outside. Seamless cans and laminates of clear polyester molecular orientation film layer / adhesive / surface treated aluminum alloy plate / adhesive / titanium dioxide-containing polyester molecular orientation film layer / printing ink layer / finish varnish layer Has been described.

[0005] The titanium dioxide-containing polyester molecular orientation film layer present on the outer surface of the seamless can conceals the chromium surface-treated layer, raises the printing ink layer, and improves the transmission of wrinkle suppressing force during drawing and redrawing. Although it performs a desired action such as preventing the occurrence of wrinkles in the can body and assisting in rust prevention, it has been found that the following problems still exist.

That is, in order to increase the hiding power of the pigment particle-containing resin outer layer, it is necessary to increase the content of pigment particles such as titanium dioxide. However, when the content of pigment particles is increased, draw molding or ironing is performed. There is a disadvantage that the outer layer resin film is shaved during molding, and this tendency becomes more remarkable as the thickness of the can body is made thinner in order to save the material and reduce the weight.

In order to solve such a problem, the inventors of the present invention have proposed a method for manufacturing a laminated plate made of a metal plate and a thermoplastic resin layer provided on the surface of the metal plate, wherein the thermoplastic resin layer is A polyester-based resin intermediate layer (A) containing 10% by weight or more of pigment particles and a polyester-based resin containing 20% by weight or less of pigment particles and containing pigment particles at a lower concentration than the intermediate layer There has already been proposed a can-made laminate plate comprising a laminated film layer comprising a surface layer (B) and a polyester resin base layer (C) (Japanese Patent Application Laid-Open No. 9-295374).

On the other hand, an important practical property of a canned product is dent resistance. In this denting test, an impact such as a dent is given to a can, and when this dent occurs, Is also to test whether the coating of the can body is completely maintained, but in actual canned products,
Since barriers due to dropping and collision between cans often occur, it is also required in this case that the coating does not peel off or the coating film such as cracks or pinholes does not drop. In particular, in a seamless can made by thinning a resin-coated laminate by drawing and ironing, dents are likely to occur due to impact, and the coated resin film is stretched, often resulting in poor adhesion, especially dent resistance. Sex matters.

[0009]

However, according to the above-mentioned prior art, although the abrasion of the outer layer resin film is considerably reduced, the laminating plate having the coating layer containing a large amount of the pigment has a problem that the pigment particles are not removed. Due to the presence, molecular orientation is likely to occur, which causes a problem that processability and adhesion are reduced. Increasing the orientation of the resin film in the laminate film is effective in improving the barrier properties against corrosive components and improving the corrosion resistance, but on the other hand, the brittleness increases, the processability decreases, and the seamless When this is done, the impact resistance such as dent resistance tends to decrease.

In general, the degree of molecular orientation of a resin coating is measured by measuring the birefringence distribution in the thickness direction of the resin film, but for a laminated plate coated with a pigment particle-containing resin film, Because the contained pigment particles do not transmit light, its measurement was difficult,
It was unclear how a birefringent distribution in the thickness direction of the pigment particle-containing resin film could be obtained to obtain a laminate having excellent moldability and excellent adhesion. In addition, it was difficult to measure characteristics between layers having different pigment contents. Therefore, an object of the present invention is to reduce the scraping of the film layer during can-making while containing a pigment, and also have excellent corrosion resistance, and excellent concealability due to an increase in whiteness, In addition, on the outer surface, a laminate for can-making with improved printing quality, and the impact resistance (dent resistance) obtained by using this laminate
To provide a coated seamless can excellent in quality.

[0011]

According to the present invention, a surface resin layer (a) having a pigment content of 20% by weight or less and a pigment content of 10 to 70% by weight and a pigment content of In a laminated plate in which a resin film containing more resin layers (b) than a resin layer (a) is coated on a metal plate, the resin layer (b) of the laminated plate exists as a base layer, and the resin layer (b) The birefringence of the film part in contact with the metal plate (Δ
n) is not more than 0.1 and not more than the value of birefringence of the film portion on the front surface side, wherein Δn = nm−nt (1) nm is refraction in the maximum orientation direction of the film. And nt is the refractive index in the thickness direction of the film. According to the present invention, there is also provided a surface resin layer (a) having a pigment content of 20% by weight or less, and a pigment content of 10 to 70% by weight.
A resin film including an intermediate resin layer (b) having a higher pigment content than the surface resin layer (a) and a base resin layer (c) having a pigment content of 20% by weight or less is laminated on a metal plate. In the laminated plate, the birefringence (Δn) of the film portion of the base resin layer (c) in contact with the metal plate is 0.1 or less, and the birefringence value of the surface side film portion or less. (1) where nm is the refractive index in the maximum orientation direction of the film, and nt is the refractive index in the thickness direction of the film. In the laminate plate for a can of the present invention, 1. The birefringence (Δn) of the portion on the surface side of the laminated film is 0.005 to 0.14; A portion having a different birefringence value exists on the inner side in the thickness direction from the surface side of the laminated film, and the value of the birefringence (Δn) of the different portion is in the range of 0.02 to 0.14, and It is preferable that the value is not less than the value of the birefringence of the film portion and the value of the birefringence of the film portion in contact with the metal.

According to the present invention, there is further provided a coated seamless can, which is obtained by drawing or ironing the laminated plate described above. In the coated seamless can of the present invention: At the upper part of the side wall of the seamless can, the birefringence (Δn) of the film portion in contact with the metal plate is 0.1 or less and the birefringence value of the film portion on the surface side is less than or equal to: Δn = nh−nt (2) nh is the refractive index in the direction of the can axis of the film, and nt is the refractive index in the thickness direction of the film; 2. The birefringence ([Delta] n) of the upper portion of the side wall of the seamless can on the film surface side is 0.01 to 0.18; In the upper part of the side wall of the seamless can, there is a portion having a different birefringence value on the inner side in the thickness direction from the film surface side, and the birefringence (Δn) of the different portion is 0.02.
3. Within the range of 0.18, which is not less than the birefringence value of the surface side film portion and the birefringence value of the film portion in contact with the metal; 4. In the upper part of the side wall of the seamless can, there is a birefringence peak near the film portion in contact with the metal plate, and the peak value (Δn) is 0.02 to 0.18; In drawing or ironing, it is preferable that the side wall portion of the can is thinned to 30 to 90% of the original thickness of the laminated laminate.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Function] The laminated plate for cans of the present invention comprises a resin layer containing a predetermined amount of pigment and having a predetermined birefringence as a surface resin film of a metal plate, for example, as shown in FIG. It is covered with such a two-layer structure or a three-layer structure as shown in FIG.

That is, in FIG. 1, which shows an example of a cross-sectional structure of a laminated plate for can-making according to the present invention, this laminated plate 1 is provided on a metal plate 2 and a surface of the metal plate 2 which is to be an outer surface or an inner surface of the can. The resin film 3 comprises (a) a surface resin layer 4 located at the outermost surface and containing 20% by weight or less of pigment particles, and (b) located at a metal plate side and having a thickness of 10 to 70%. And a base resin layer containing 5% by weight of pigment particles and containing more pigment particles than the surface resin layer. In FIG. 2, which shows another example of the cross-sectional structure of the laminated plate for cans of the present invention, the laminated plate 1 is a resin film applied to a metal plate 2 and a surface of the metal plate which is to be the outer surface or inner surface of the can. The resin film 3 comprises (a) a surface resin layer 4 located at the outermost surface and containing 20% by weight or less of pigment particles, and (b) located at an intermediate position and 10 to 70% by weight or less. An intermediate resin layer 5a containing pigment particles and containing more pigment particles than the surface resin layer 4, and a base resin layer (c) 6 having a pigment content of 20% by weight or less are provided. In both cases of FIGS. 1 and 2, the side of the metal plate 2 that is to be the other surface of the can is
A pigment-containing or clear polyester layer 7 is laminated. Although not shown, the metal film 2 may be coated with a resin film 3 on the outer and inner surfaces of the can.

As has already been pointed out, it is necessary to increase the concentration of the pigment particles in the resin in order to increase the hiding power of the metal plate by the resin coating in the can-made laminate plate. In the invention, the resin film layer to be the outer surface or the inner surface of the can is formed by a two-layer structure of a surface layer (a) and an underlayer or an intermediate layer (b), or a three-layer structure of an underlayer (c). The base layer or the intermediate layer (b) has a laminated structure, in which 10 to 70% by weight of pigment particles larger than the pigment particles of the outermost layer (a) is blended to improve the hiding power. By blending pigment particles in the surface layer (a) at a lower concentration than in the intermediate layer, it is possible to prevent the film from being scraped during drawing and ironing.

Please refer to FIG. 3 of the accompanying drawings. FIG. 3 is a plot of the relationship between the blended amount of titanium oxide and the stress in a film tensile test. The results show that as the content of titanium dioxide increases, the stress decreases. If the strength of the film is lower than a certain standard, the film breaks at the time of lamination, and the productivity is undesirably reduced.

In the present invention, by increasing the amount of the pigment in the underlayer or the intermediate layer and decreasing the amount of the pigment in the surface layer, it is possible to prevent breakage of the film at the time of lamination and to form a seamless can. This also prevents the occurrence of film scraping at the time.

On the other hand, in the case of a multilayer film containing a pigment, the degree of molecular orientation of the resin layer containing a large amount of the pigment becomes large, and if a high molecular orientation remains in the film portion of the laminate plate in contact with the metal, the resin layer is processed. This causes a problem that the adhesiveness of the film is reduced at the time of storage or storage as a can.

In the laminate for cans of the present invention,
A multi-layer resin film containing a pigment in a specific ratio is laminated on a metal plate, and the value of the birefringence (Δn) of the film portion of the base resin layer (b) or (c) in contact with the metal plate is 0.1 or less. In addition, by suppressing the birefringence value of the surface side film portion or less, the above problem was solved while using a multilayer film containing a large amount of pigment, and the adhesion was successfully improved. .

That is, in the present invention, it is possible to measure the birefringence of a pigment-containing resin film, which has been difficult to measure conventionally, and the birefringence is extremely 0.1 or less at a portion of the base resin layer in contact with the metal plate. The inventors have found that a small-sized can-made laminate plate is excellent in moldability and adhesiveness of resin coating, and further, has excellent dent resistance when the can-made laminate plate is made into a seamless can. The birefringence in question in the present invention has a close relationship with the molecular orientation in the film, and this molecular orientation has an amorphous orientation in addition to what is called an oriented crystal. The required birefringence is related to these totals.

In the present invention, the measurement of birefringence of a resin film containing pigment particles, which has been difficult to measure conventionally, can be performed by the following method. FIG.
Is a flowchart showing the measurement principle.

"Method of preparing specimen and measuring birefringence"
Hereinafter, a method for preparing a sample piece and a method for measuring birefringence used in the present invention will be described, but it is needless to say that the present invention is not limited thereto. First, from the laminated plate, cut out a 100 mm square material centered on the position that should be the can bottom center after molding, and from the top of the can side wall, on the axis in the direction perpendicular to the rolling direction of the metal plate, In addition, a material having a size of about 10 mm square was cut out around a point 5 mm from the tip of the flange portion of the can, and each was sampled as a material for preparing a sample piece. For each of the cut samples, the metal plate was dissolved with hydrochloric acid having a concentration of about 20%, and the film was isolated. Thereafter, the film was vacuum dried for at least 24 hours. Next, the film obtained from the laminate plate and the side wall of the can was embedded with an epoxy resin. Thereafter, the thickness direction of the film and the maximum orientation direction of the film surface are parallel to each other for the film obtained from the laminated plate, and the thickness direction and the can length of the film obtained from the upper portion of the side wall of the can. Each sample was sliced while being embedded so that the directions were parallel to each other to obtain a sample piece. The slice thickness was 1-3 μm, and the setting of the thickness was changed as needed depending on the sample. The slice thickness was set to be relatively small for films having a large content of titanium dioxide and films expected to have a large value of birefringence. The method of measuring the birefringence in the film thickness direction of the cross section of the sliced sample piece will be described below. The birefringence can be calculated by determining the retardation R (nm) of the film thickness direction portion of each sample piece by a general birefringence measurement method using a polarizing microscope. The sample piece is placed at the subtraction position with respect to the compensator with the polarization directions of the polarization obtained by the polarizer and analyzer of the polarization microscope orthogonal to each other (orthogonal Nicols), and the monochromatic light with the measurement wavelength λ = 546 nm is used as the incident light. Then, rotate the analyzer so that the polarization microscope image of the measurement portion becomes the darkest. Assuming that the rotation angle of the analyzer at this time is θ degrees, the retardation R (nm) is expressed by the following equation (A).
Can be obtained from R = λ × θ / 180 (A) From this, birefringence of the film obtained from the laminate plate
(nm-nt) and the birefringence (nh-nt) of the film obtained from the upper portion of the can side wall can be calculated from the equations (B) and (C), respectively. (nm−nt) = R / d = λ × θ / d / 180 (B) (nh−nt) = R / d = λ × θ / d / 180 (C) where d Is the slice thickness (nm). In the measurement of birefringence in the present invention, the birefringence of an object, which includes a CCD microscope, a computer, and image processing software and data processing software operating on the computer in addition to a polarizing microscope, is automatically determined by computer image processing. The measurement was carried out by a system capable of measuring at a time. FIG. 4 shows a flowchart of a birefringence measurement method using this system. The macro program shown in the figure links the image processing software and the data processing software to automatically execute the input of the polarization microscope image to the computer, a series of data processing, the calculation of birefringence, and the like. . Hereinafter, an outline of the processing of the present measurement system will be described.
First, the analyzer of the polarizing microscope is rotated at a predetermined fixed pitch in a range of 0 to 180 degrees in a predetermined measurement range of the sample piece in the film thickness direction, and a polarizing microscope image at each rotation angle is obtained by a CCD camera. To the computer sequentially. Each image input to the computer is converted into a brightness value by the image processing software. Next, the rotation angle of the analyzer at which the polarization microscope image becomes the darkest (the brightness value becomes the minimum) in the measurement range of the sample piece in the film thickness direction is obtained by the data processing software, and the above-described equation (A) is obtained from this. )
And the birefringence is calculated based on the calculation method shown in Expression (B) or Expression (C). The main device names and software names that constitute the measurement system are as shown below.
It is needless to say that the birefringence can also be measured by visually observing an image of a polarizing microscope without using this system.・ Polarization microscope: OPTIPHOT2-POL manufactured by Nikon Corporation (using a Senarumon type compensator) ・ CCD camera: CC-990 manufactured by FLOVEL ・ Computer: FMV-5133D5 manufactured by Fujitsu Ltd. ・ Image processing software: Ima manufactured by Media Cybernetics
ge-Pro PLUS-Data processing software: In measuring the birefringence of an Excel sample from Microsoft, five points were measured and the average value was determined and used as the measured value. Each measurement value may include a value that is clearly judged to be an abnormal value due to scratches generated during slicing or derived from titanium oxide contained in the film, etc. The results obtained by removing abnormal values by observing and judging from measured values before and after the abnormal values were adopted.

In the laminated plate of the present invention, the birefringence can be determined by the above-mentioned measuring method, and the birefringence (Δn) of the underlayer film portion in contact with the metal plate side is 0.1.
In the following, when the content is in the range of 0.07 or less, the adhesion to the metal plate and the workability are excellent, and the adhesion and the dent resistance when a seamless can is obtained are improved.
This will be clearer with reference to the examples below.

In the laminated plate of the present invention, particularly, the birefringence (Δn) of the portion on the film surface side is 0.00
It is preferably from 5 to 0.14. As described above, increasing the orientation of the laminate film is effective in improving the barrier property against corrosive components and improving the corrosion resistance, so that only the film surface side particularly involved in the barrier property is as described above. By having birefringence, it is possible to achieve both excellent workability, adhesion and dent resistance of the film portion in contact with the metal plate side, and corrosion resistance on the surface side.

In the laminated plate of the present invention, the thickness of the laminated resin film is larger than the surface of the laminated resin film.
A portion having a different birefringence value may exist, the value of the birefringence (Δn) of the different portion is 0.02 to 0.14, and the value of the birefringence of the surface side film portion and the film in contact with the metal It is preferable that the value is not less than the value of birefringence of the portion.
That is, as described above, it is pointed out that the degree of molecular orientation is increased in the resin layer having a high pigment content in the multilayer film, but in the preferred embodiment of the present invention, the surface side film portion and the film portion in contact with the metal plate By preserving a highly oriented portion related to the pigment composition between the above, the barrier property against corrosive components can be improved.

FIG. 5 is a diagram showing the distribution of the birefringence in the thickness direction of the pigment particle-containing resin film in one example of the laminate plate of the present invention. It will be appreciated that the birefringence has a small value. Further, FIG. 6 is a view showing the thickness direction distribution of the birefringence of the pigment particle-containing resin film layer in another example of the laminated plate of the present invention, and shows the difference between the surface side film portion and the film portion in contact with the metal plate. In addition, it will be understood that, in addition to preserving the highly oriented portions related to the pigment formulation, the birefringence is small at the portion in contact with the metal plate. It is considered that this highly oriented region having a large birefringence serves as a barrier against corrosion components.

On the other hand, even in a coated seamless can obtained by drawing or ironing the laminated plate for can making of the present invention, the distribution of the pigment content in the resin in the thickness direction is maintained similarly to that of the laminated plate. However, the distribution of the birefringence in the thickness direction is preferably maintained in the same tendency as that of the laminate. That is, in a coated seamless can, draw-forming or ironing causes plastic deformation such that the dimension increases in the height direction of the can and the dimension decreases in the circumferential direction of the can. As the orientation in the can axis direction occurs, the relationship between the birefringence and the adhesion and corrosion resistance of the resin coating has the same tendency as in the case of the laminate plate, and it also has the dent resistance. is there.

In the upper portion of the can side wall of the seamless can, the birefringence (Δn) of the film portion in contact with the metal plate is 0.1 or less, and the birefringence value of the film portion on the surface side is also less than 0.1. This is important in terms of adhesion to the plate. In addition, at the upper part of the side wall of the seamless can,
Birefringence (Δn) of the film surface side portion is 0.01 to
0.18 is preferable from the viewpoint of corrosion resistance. Furthermore,
In the upper part of the can side wall of the seamless can, a portion having a different birefringence value exists on the inner side in the thickness direction from the surface side of the film, and the birefringence (Δn) of the different portion is 0.02 to 0.02.
It is most preferably 0.18, which is not less than the value of the birefringence of the surface side film portion and the value of the birefringence of the film portion in contact with the metal, from the viewpoint of adhesion to metal, corrosion resistance, and workability. Further, at the upper part of the side wall of the seamless can of the present invention, there is a birefringence peak near the film portion in contact with the metal plate, and the peak value (Δn) is 0.02 to 0.02.
It may be 0.18, which is particularly excellent in corrosion resistance. In drawing or ironing, it is preferable that the side wall of the can be reduced to 30 to 90% of the original thickness of the laminated laminate from the viewpoint of reducing the weight of the container, saving resources, and reducing costs.

FIG. 7 is a graph showing the distribution of the birefringence of the pigment-containing film in the thickness direction in one example of the coated seamless can of the present invention. As in FIG. 5, the birefringence is large on the surface side of the film. It will be understood that the birefringence has a small value at the portion in contact with the metal plate. Also, between the film surface side part and the film part in contact with the metal plate,
It will also be appreciated that there are intermediate portions of different birefringence. Further, FIG. 8 is a view showing the thickness direction distribution of the birefringence of the pigment particle-containing film layer in another example of the coated seamless can of the present invention. As in the case of FIG. In addition to the film part in contact with, to preserve the high orientation part related to the pigment composition, in addition to the small value of birefringence in the part in contact with the metal plate,
It will be understood that there is an intermediate portion in which the birefringence peaks and exhibits a maximum value near the portion in contact with the metal plate.
Then, it is considered that the intermediate region where the birefringence shows a peak serves as a barrier against corrosion components.

In the coated seamless can of the present invention, drawing or ironing causes plastic flow such that the dimension increases in the height direction of the can and the dimension decreases in the circumferential direction of the can. Although the orientation has occurred, since the orientation is relaxed in the heat treatment step during can making,
Birefringence is suppressed to a low range in the part in contact with the metal plate,
The adhesiveness to the metal plate and the corrosion resistance are excellent, and the dent resistance is also excellent.

(Metal Sheet) In the present invention, various metal sheets such as surface-treated steel sheets and aluminum are used as the metal sheet. As the surface-treated steel sheet, a cold-rolled steel sheet is subjected to one or two or more surface treatments such as annealing, secondary cold-rolling, zinc plating, tin plating, nickel plating, electrolytic chromic acid treatment, and chromic acid treatment. Can be used. An example of a suitable surface-treated steel sheet is an electrolytic chromic acid-treated steel sheet, particularly a metal chromium layer of 10 to 200 mg / m ^{2 and} a metal chromium layer of 1 to 5 mg / m ^2.
It is provided with a chromium oxide layer of 0 mg / m ² (in terms of chromium metal), and is excellent in combination of coating film adhesion and corrosion resistance. Another example of the surface-treated steel sheet is 0.
It is a hard tin plate having a tin plating amount of 5 to 11.2 g / m ² . This tin plate is desirably subjected to a chromic acid treatment or a chromic acid-phosphoric acid treatment such that the amount of chromium is 1 to 30 mg / m ^{2 in} terms of metal chromium.

As still another example, an aluminum-coated steel sheet subjected to aluminum plating, aluminum pressure welding, or the like is used. As the light metal plate, an aluminum alloy plate is used in addition to a so-called aluminum plate. An aluminum alloy sheet excellent in corrosion resistance and workability is Mn:
0.2 to 1.5% by weight, Mg: 0.8 to 5% by weight,
Zn: 0.25 to 0.3% by weight, and Cu: 0.15
To 0.25% by weight, with the balance being Al. It is desirable that these light metal plates are also subjected to chromic acid treatment or chromic acid / phosphoric acid treatment so that the amount of chromium becomes 20 to 300 mg / m ^{2 in} terms of chromium metal. Further, the surface may be treated with a chemical conversion film containing zirconium or titanium oxide as a main component or a composite film of polyacrylic acid-zirconium salt. The amount of the film is preferably about 5 to 300 mg / m ² as a solid content. The thickness of the metal plate, that is, the thickness of the bottom of the can (tB
) Varies depending on the type of metal, the use or size of the container, but generally has a thickness of 0.10 to 0.50 mm. Among them, in the case of a surface-treated steel sheet, 0.10 to 0. The thickness is preferably 30 mm, or 0.15 to 0.40 mm in the case of a light metal plate.

(Pigment) In the present invention, the content of the pigment to be contained in the resin film is, as described above, when the resin layer is composed of the surface resin layer (a) and the base layer of the resin layer (b). 20% by weight or less of the surface resin layer (a);
The resin layer (b) is 10 to 70% by weight and the surface resin layer (a)
To do more than. Further, the resin layer is a surface resin layer (a),
In the case of comprising the intermediate resin layer (b) and the base layer (c), the surface resin layer (a) and the base layer are not more than 20% by weight, and the intermediate resin layer (b) is 10 to 70% by weight. a)
To do more than. By setting the content of the pigment in each layer within the above range, the concealing property is improved. On the other hand, the surface resin layer (a) is blended with pigment particles at a lower concentration than that of the intermediate layer, so that it can be used during drawing and ironing. Can be prevented from being scraped off. Furthermore, even when forming a laminated film and laminating to a metal plate, no distortion occurs, and lamination and bonding can be performed with good workability.

Suitable examples of the pigment which can be contained in the resin film of the laminate of the present invention are as follows. Black pigments Carbon black, acetylene black, run black, aniline black. Yellow pigment Yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navels yellow, naphthol yellow S, Hanza yellow G, Hanza yellow 10G, benzidine yellow G,
Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake. Orange pigments Red mouth lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, induslen brilliant orange RK, benzidine orange G, induslen brilliant orange GK. Red pigment Bengala, cadmium red, lead red, cadmium mercury sulfide, permanent red 4R, lithol red, pyrazolone red, watching red calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake, brilliant carmine 3B. Purple pigment Manganese purple, fast violet B, methyl violet lake. Blue pigment Navy blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, first sky blue, indaslen blue B
C. Green pigment chrome green, chromium oxide, pigment green B,
Malachite Green Lake, Fanal Yellow Green G. White pigments zinc white, titanium dioxide, antimony white, zinc sulfide. Extender barite powder, barium carbonate, clay, silica, white carbon, talc, alumina white.

The particle size of the pigment is generally 0.1 to 2.5 μm.
m, particularly preferably in the range of 0.1 to 2.0 μm. That is, if the particle size is too large, the drawability tends to be poor, while if the particle size is too small, the hiding power tends to decrease. Particularly suitable pigments for the purposes of the present invention are titanium dioxides, in particular of the rutile or anatase type, which are white and have great hiding power. Titanium dioxide is also excellent in rust prevention.

(Resin Film) The resin film to be laminated on the metal plate in the present invention is a multilayer resin film containing a pigment at a predetermined concentration. As the resin, any known resin used for this type of application can be used, but a polyester resin is preferable. As the polyester resin, ethylene terephthalate,
Ethylene isophthalate, butylene terephthalate, polyester comprising at least one ester unit selected from the group consisting of butylene isophthalate and ethylene naphthalate, drawing ironability, mechanical strength, corrosion resistance, Preferred in terms of heat resistance,
The polyester may be a homopolyester, a copolyester composed of two or more of the above ester units, or one or more of the above ester units and one or more of the other ester units. May be used as the polyester blend.

The polyester resin used in the present invention is generally preferably a homopolyester or a copolyester derived from a dibasic acid mainly composed of terephthalic acid and a diol mainly composed of ethylene glycol.

Acid components other than terephthalic acid include isophthalic acid, P-β-oxyethoxybenzoic acid, naphthalene-2,6-dicarboxylic acid, diphenoxyethane-4,
Dibasic acids such as 4′-dicarboxylic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid, hemi-mellitic acid, 1,1,2,2- Ethanetetracarboxylic acid, 1,1,2-ethanetricarboxylic acid, 1,
3,5-pentanetricarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, biphenyl-3,4
Examples include polybasic acids such as 3 ′, 4′-tetracarboxylic acid. Of course, these may be used alone or in combination of two or more.

The alcohol components other than ethylene glycol include propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexylene glycol, diethylene glycol, triethylene glycol, cyclohexanedimethanol, and ethylene of bisphenol A. Diols such as oxide adducts,
Examples include polyhydric alcohols such as pentaerythritol, glycerol, trimethylolpropane, 1,2,6-hexanetriol, sorbitol, and 1,1,4,4-tetrakis (hydroxymethyl) cyclohexane. Of course, these may be used alone or in combination of two or more.

As the diol component of the copolymerized polyester, those mainly composed of ethylene glycol are preferred.
It is advantageous from the mechanical properties that 95 mol% or more, especially 98 mol% or more of the diol component is composed of ethylene glycol.

These homopolyesters or copolymerized polyesters should have a molecular weight in the range of forming a film, and have an intrinsic viscosity [IV] of 0.5 to 1 when measured using a phenol / tetrachloroethane mixed solvent as a solvent. 5, preferably in the range of 0.6 to 1.5.

Suitable copolyesters are, on average, 98-80% terephthalic acid and 2-20% isophthalic acid.
%. The average means that the polyester film may be a blend of a plurality of copolyesters having different isophthalic acid contents or a laminate of a plurality of copolyesters having different isophthalic acid contents. It means that it may be a film. The melting point of the copolymerized polyester is preferably in the range of 180 to 270 ° C.

(Multilayer Film) The resin film used in the present invention has a surface resin layer (a) having a pigment content of 20% by weight or less, a pigment content of 10 to 70% by weight and a pigment content of 10% to 70% by weight. It may be a two-layer resin film including a resin layer (b) larger than the resin layer (a), or a surface resin layer (a) having a pigment content of 20% by weight or less, and a pigment layer having a pigment content of 10% or less. A three-layer resin including an intermediate resin layer (b) having a pigment content of 20 to 70% by weight or less and a base resin layer (c) having a pigment content of 20% by weight or less. It may be a film. Of course, the resin film used in the present invention is not strictly limited to those described above,
As long as the resin layer of (b) or (c) is provided, any other resin layer may be interposed.

The thickness ratio of each resin layer is not particularly limited. However, from the viewpoint of hiding by a pigment and other physical properties, in the case of a two-layer resin film, the thickness ratio is (a) :( b) = 1: 2 to 1:50, and in the case of a three-layer resin film,
The thickness ratio is preferably in the range of (a) :( b) = 1: 2 to 1:50 (b) :( c) = 2: 1 to 50: 1.

As the pigment-containing resin film layer used in the present invention, the resin may be extruded in a molten state or may be an unstretched film (cast film). In view of this, a biaxially stretched film is preferred. The multilayer film is extruded using a number of extruders corresponding to the type of the resin layer, kneading the resin and the pigment, co-extruding through a multilayer multiple die, rapidly cooling the extruded multilayer film, and stretching the supercooled film at a stretching temperature. And then biaxially stretched.

The pigment-containing multilayer resin film layer used in the present invention is preferably biaxially stretched, and has a thickness of 2 to 50 μm, particularly preferably 5 to 50 μm. When the thickness is smaller than the above range, the corrosion resistance is not sufficient. On the other hand, when the thickness is larger than the above range, the drawability tends to decrease. The degree of biaxial stretching of the pigment-containing multilayer resin film is preferably such that the stretching ratio in the machine direction is 2 to 5 times and the stretching ratio in the transverse direction is 2 to 5 times. The film is preferably heat-set after stretching, and the heat-setting temperature (Th) varies depending on the melting point of the resin and the amount of the pigment, but is particularly preferably set at a temperature of 140 to 220 ° C. Is preferred.

(Production Method of Laminated Plate) In the production of a laminated plate using a biaxially stretched film, generally, a metal plate is heated to a temperature (T ₁ ) higher than a melting point (Tm) of a resin film used by a heating roll or the like. It is performed by supplying between the laminating rolls. On the other hand, the stretched resin film is unwound from a supply roll and supplied in a positional relationship of sandwiching a metal plate between laminate rolls adjusted to a predetermined temperature (T ₂ ) to thermally bond the film to the surface of the metal plate. Let it. A water tank containing cooling water for quenching the laminate to be formed is provided below the laminating roll, and a guide roller for guiding the laminating is disposed in the water tank, and the laminate discharged from the laminating roll is guided into the cooling water. And quench. The heating temperature (T ₁ ) of the metal plate is from Tm-50 ° C. to Tm based on the melting point (Tm) of the resin film.
The temperature within the range of + 50 ° C. is preferable from the viewpoint of obtaining the heat adhesive property and the birefringence property specified in the present invention. On the other hand, the temperature (T ₂ ) of the laminating roll is the heat setting temperature (T
h) lower than the glass transition point (Tg) of the resin film
The above temperature is preferable for the same reason. Birefringence of the resin coating layer of the laminate plate, the type of resin of the film, the content of pigment particles, the degree of molecular orientation of the film, the thickness of the film, the metal plate temperature during lamination,
Since the temperature of the laminating roll at the time of lamination, the cooling rate and the like are significantly different, the conditions for setting the birefringence within the above-described range cannot be unconditionally defined, but can be experimentally determined based on the above temperature. . For example, when the degree of molecular orientation of the biaxially stretched film is high, the temperature of the metal plate is increased to relax the orientation of the film portion that is in contact with the metal plate, so that the film portion that is in contact with the metal plate in the laminate is duplicated. Since the refraction can be suppressed low, the birefringence index can be controlled using such a tendency. More specifically, a certain resin, a certain pigment particle content, a certain degree of molecular orientation,
Examining the metal plate temperature and the birefringence of the laminate film for a film of a certain thickness, there is a one-to-one correspondence between the metal plate temperature and the birefringence of the film that is thermally bonded to it. Thus, the lamination conditions for obtaining a predetermined birefringence can be determined. Since the correspondence between such a factor of the lamination and the birefringence also applies to other than the temperature of the laminating roll, lamination conditions for setting the birefringence within the above-described range can be easily determined by those skilled in the art by simple experiments. .

In the production of a laminate plate by extrusion coating, generally, a metal plate is preheated by a heating device.
It is supplied to a pair of laminate rolls. On the other hand, a resin film is extruded in the form of a plurality of thin films from a die head of an extruder arranged on both sides of a metal plate, and supplied between a laminating roll and a metal plate. Both are thermally bonded and cooled from both sides to obtain a laminate. Next, the above-mentioned laminated plate is further guided to a cooling water tank or the like to be rapidly cooled.

In the production of a laminated plate from a resin-unstretched film formed in advance, a metal plate is heated by a heating roll and supplied between the laminating rolls, while the resin film is unwound from the supply roll. Are supplied in a positional relationship of sandwiching a metal plate between laminating rolls. The laminating roll is maintained at a slightly higher temperature than the heating roll, and a resin film is thermally bonded to both surfaces of the metal plate to form a laminated plate, which is guided to a cooling water tank below the laminating roll to perform rapid cooling.

In the present invention, a pigment-containing resin film can be directly provided on a metal plate, but a conventionally known adhesive primer layer can be provided between the metal plate and the pigment-containing resin film. This adhesive primer exhibits excellent adhesiveness to both the metal material and the film. Primer coatings with excellent adhesion and corrosion resistance include phenol-epoxy coatings composed of resole-type phenolaldehyde resins derived from various phenols and formaldehyde, and bisphenol-type epoxy resins. 5 resin
It is a coating composition containing at a weight ratio of 0:50 to 1:99, particularly at a weight ratio of 40:60 to 5:95. The adhesive primer layer is generally preferably provided with a thickness of 0.01 to 10 μm. The adhesive primer layer may be provided on a metal material in advance, or may be provided on a pigment-containing resin film. Although not generally required, when using an adhesive primer,
It is generally desirable that the surface of the resin film be subjected to a corona discharge treatment in order to increase the adhesiveness with the adhesive primer to the film. It is desirable that the degree of the corona discharge treatment is such that the wetting tension is 3040 dyne / cm or more. In addition, it is also possible to perform a known surface treatment for improving the adhesiveness such as a plasma treatment or a flame treatment on the film, or a coating treatment for improving the adhesiveness of a urethane resin or a modified polyester resin.

The resin film may be blended with a known film compounding agent, various antistatic agents, lubricants and the like according to a known formulation.

As the other resin layer provided on the inner surface side of the can, a similar polyester film containing or not containing a pigment is used. This film may be a single-layer film or a laminated film.

(Production of Seamless Can) The metal can made of the laminated plate for can-making of the present invention has the excellent properties of the laminated plate as long as it is formed from the laminated plate for can-making described above. Although it can be manufactured by a can manufacturing method and can be a three-piece can having a side seam,
In particular, a seamless can is preferable. The seamless can (two-piece can) composed of the laminated plate of the present invention is drawn and re-wrung, drawn and drawn so that the coating surface of the pigment-containing resin film of the above-mentioned laminated plate is on the outer surface side of the can and / or the inner surface side of the can. It is manufactured by subjecting it to conventionally known means such as bending and stretching by thinning (thinning drawing), bending and stretching by drawing and redrawing, or drawing and ironing. The seamless can of the present invention is manufactured by the above-mentioned means. Preferably, the side wall is thinned by bending and stretching by redrawing and / or ironing. The thickness of the laminate is reduced by bending and / or ironing the side wall portion compared to the bottom portion so that the side wall portion has a thickness of 20 to 95%, particularly 30 to 90% of the original plate thickness of the laminate plate. Is preferred.

The obtained can is subjected to at least one stage of heat treatment to remove residual distortion of the film caused by processing.
The lubricant used in the processing is volatilized from the surface, and the printing ink printed on the surface is dried and hardened. This heat treatment gives the distribution of the above-mentioned birefringence value to the seamless can. Generally, the heat treatment conditions are such that the value of the above-mentioned birefringence is from the range of 180 to 240 ° C. and the time of 1 second to 10 minutes. It is good to set conditions so that it can be obtained. That is, as the processing temperature increases, the value of birefringence tends to decrease, and as the processing time increases, the value of birefringence tends to decrease.Therefore, it is possible to determine the optimal condition based on these trends. it can. Of course, a plurality of stages of heat treatment can be performed. The container after the heat treatment is quenched or allowed to cool, and then subjected to a single-stage or multi-stage neck-in process, if necessary, and subjected to a flange process to obtain a can for winding. After the seamless can is formed, the upper portion of the seamless can can be deformed to form a bottle.

As described above, the laminated plate for cans of the present invention has the excellent properties of the laminated plate as it is, even if the thickness is reduced by drawing and ironing, and the resin coated on the metal plate. From the viewpoint that the film is thinned and the dent resistance is improved even when stretched and oriented, it is particularly suitable for the production of seamless cans, but even when used for three-piece cans and drawn cans, it is the same as a laminated plate And it is possible to express the excellent characteristics of the laminate as it is.

[Experimental Example] Experimental Example 1 One side (surface to be the outer surface of the container) of tin-free steel (TFS: electrolytic chromic acid-treated steel plate) having a base plate thickness of 0.18 mm and a temper degree of DR-6. Biaxially stretched isophthalic acid copolymerized polyethylene terephthalate film having a thickness of 17 μm and a melting point of 225 ° C. (stretching ratio: 3.0 times, 3.0 times wide, heat setting temperature: 180 ° C.) having the thickness shown in Experimental Example 1 of Table 1
With a thickness of 25 μm on the other surface (the surface to be the inner surface of the container).
m, a single-layer biaxially stretched film of isophthalic acid copolymerized polyethylene terephthalate having a melting point of 225 ° C. (stretching ratio of 3.0
2 times, 3.0 times wide, heat setting temperature is 180 ° C)
30 ° C, laminating roll temperature 140 ° C, threading speed 20
The laminate was thermally laminated at m / min and immediately cooled with water to obtain a laminated metal plate. A wax-based lubricant was applied to both sides of this laminated plate, and a circular blank having a diameter of 166 mm was punched out to obtain a shallow drawn cup. Next, the shallow drawn cup was thinned and redrawn and ironed to obtain a deep drawn ironed cup. The properties of the deep drawn ironing cup were as follows. Cup diameter 60 mm Cup height 128 mm Thickness of the side wall of the can 65% of the original plate thickness
After heat treatment at 215 ° C., the cup was allowed to cool, and then subjected to trimming processing, curved surface printing and baking drying, necking processing, and flanging processing to obtain a 350 g seamless can. Table 1 shows the results of continuous can making and the results of storage tests. 100,000 cans were made continuously, but the can making condition was stable and there was no appearance defect such as scraping of the film on the outer surface. There was no problem in the adhesion between the wound portion and the neck portion, and the storage test was good.

Experimental Example 2 A laminating roll temperature of 100 ° C. and a passing speed of 5 m / min.
A laminate plate was obtained in the same manner as in Experimental Example 1 except that a biaxially stretched film of isophthalic acid copolymerized polyethylene terephthalate having the constitution shown in Experimental Example 2 in Table 1 was used on the surface to be an outer surface, and a 350 g seamless can was obtained. Was. Table 1 shows the results of continuous can making and the results of storage tests. 100,000 cans were made continuously, but the can making condition was stable and there was no appearance defect such as scraping of the film on the outer surface. There was no problem in the adhesion between the wound portion and the neck portion, and the storage test was good.

EXPERIMENTAL EXAMPLE 3 A plate temperature of 225.degree. C., a laminating roll temperature of 80.degree. C., a passing speed of 20 m / min, and a biaxial isophthalic acid copolymerized polyethylene terephthalate having the constitution shown in Experimental Example 3 of Table 1 A laminated plate was obtained in the same manner as in Experimental Example 1 except that a stretched film was used, and a 350 g seamless can was obtained. Table 1 shows the results of continuous can making and the results of storage tests. 100,000 cans were made continuously, but the can making condition was stable and there was no appearance defect such as scraping of the film on the outer surface. There was no problem in the adhesion between the wound portion and the neck portion, and the storage test was good.

Experimental Example 4 A laminating roll temperature of 80 ° C. and a passing speed of 40 m / min.
A laminate plate was obtained in the same manner as in Experimental Example 1 except that a biaxially stretched film of isophthalic acid copolymerized polyethylene terephthalate having the constitution shown in Experimental Example 4 in Table 1 was used on the surface to be the outer surface, and a seamless can for 350 g was obtained. Was. Table 1 shows the results of continuous can making and the results of storage tests. Although 100,000 cans were made continuously, the canning condition was stable and there was no appearance defect such as scraping of the film on the outer surface. There was no problem in the adhesion between the wound portion and the neck portion, and the storage test was good.

Experimental Example 5 A biaxially stretched isophthalic acid copolymerized polyethylene terephthalate film having the constitution shown in Experimental Example 5 in Table 1 was used at a plate thickness of 0.195 mm, a plate temperature of 235 ° C., and a surface to be an outer surface. A laminate was obtained in the same manner as in Experimental Example 1. A circular blank having a diameter of 163 mm was punched out of the laminated plate, and a 350 g seamless can was obtained in the same manner as in Experimental Example 1 except that the thickness of the can side wall was 50% of the original plate thickness. Table 1 shows the results of continuous can making and the results of storage tests. 100,000 cans were made continuously, but the can making condition was stable and there was no appearance defect such as scraping of the film on the outer surface. There was no problem in the adhesion between the wound portion and the neck portion, and the storage test was good.

EXPERIMENTAL EXAMPLE 6 A polyethylene naphthalate / polyethylene terephthalate copolymer having a melting point of 205 ° C. and a composition shown in Experimental Example 6 in Table 1 was applied to a surface to be an outer surface at a plate temperature of 215 ° C., a passing speed of 40 m / min. Biaxially stretched polyethylene naphthalate / polyethylene terephthalate copolymer with a melting point of 205 ° C on the surface to be used as the inner surface, using an axially stretched film (drawing ratio 2.8 times vertically, 2.8 times horizontally, heat setting temperature 160 ° C) (Stretching ratio 2.8 times length, 2.8 times width, heat setting temperature 160 ° C)
A laminate was obtained in the same manner as in Experimental Example 1 except that 25 μm was used. A circular blank having a diameter of 160 mm was punched out of the laminated plate, and the thickness of the can side wall was set to 40% of the original plate thickness, except that the thickness was 350%.
g seamless cans were obtained. The heat treatment of the cup was performed at 190 ° C. Table 1 shows the results of continuous can making and the results of storage tests. 100,000 cans were made continuously, but the can making condition was stable and there was no appearance defect such as scraping of the film on the outer surface. There was no problem in the adhesion between the wound portion and the neck portion, and the storage test was good.

EXPERIMENTAL EXAMPLE 7 A plate temperature of 235 ° C., a laminating roll temperature of 80 ° C., a passing speed of 40 m / min, and a film to be an outer surface were polybutylene having a melting point of 236 ° C. and having a structure shown in Experimental Example 7 in Table 1. Using an isophthalic acid copolymerized polyethylene terephthalate biaxially stretched film containing 30% by weight of terephthalate (stretching ratio 3.5 times in length, 3.6 times in width, heat setting temperature 1600C),
The film to be used as the inner surface is a biaxially stretched film of isophthalic acid copolymerized polyethylene terephthalate containing 30% by weight of polybutylene terephthalate having a melting point of 235 ° C. (stretching ratio: 3.0 times, 3.0 times, heat setting temperature: 160) C)), except that a laminated plate was obtained. A 350 g seamless can was obtained from this laminate in the same manner as in Experimental Example 5. Table 1 shows the results of continuous can making and the results of storage tests. Although 10,000 cans were made continuously, there were no appearance defects such as scraping of the film on the outer surface. There was no problem in the adhesion between the wound portion and the neck portion, and the storage test was good.

Experimental Example 8 The original plate thickness was 0.210 mm, the plate temperature was 245 ° C., the laminating roll temperature was 80 ° C., and the melting point of the structure shown in Experimental Example 8 in Table 1 was prepared in advance on the surface to be the outer surface. Experimental Example 1 except that a cast film of isophthalic acid copolymerized polyethylene terephthalate at 235 ° C. and a cast film of isophthalic acid copolymerized polyethylene terephthalate having a melting point of 235 ° C. 20 μm previously prepared were used on the inner surface. The same procedure was performed to obtain a laminated plate. This laminated plate was punched into a disk having a diameter of 140 mm to obtain a shallow drawn cup. Next, the shallow drawn cup was redrawn and ironed to obtain a deep drawn iron cup. The properties of the deep drawn ironing cup were as follows. Cup diameter 53 mm Cup height 140 mm Can side wall thickness 50% based on original plate thickness Performed in the same manner as in Experiment 1 to obtain a 250 g seamless can. The heat treatment of the cup was performed at 200 ° C. Table 1 shows the results of continuous can making and the results of storage tests. 100,000 cans were made continuously, but the can making condition was stable and there was no appearance defect such as scraping of the film on the outer surface. There was no problem in the adhesion between the wound portion and the neck portion, and the storage test was good.

Experimental Example 9 A laminated plate was obtained in the same manner as in Experimental Example 1 except that the original plate thickness was 0.240 mm and the plate temperature was 240 ° C. This laminated plate was punched into a disk having a diameter of 143 mm to obtain a shallow drawn cup. Next, the shallow drawn cup was redrawn and ironed to obtain a deep drawn iron cup. The properties of the deep drawn ironing cup were as follows. Cup diameter 52 mm Cup height 112 mm Thickness of the side wall of the can with respect to the original plate thickness 73% The same procedure as in Example 1 was carried out except that this deep-drawn ironing cup was subjected to doming molding for a negative pressure can to obtain a seamless can for 200 g. . The heat treatment of the cup was performed at 220 ° C. Table 1
Figure 11 shows the results of continuous can making and the results of storage tests. 100,000 cans were made continuously, but the can making condition was stable and there was no appearance defect such as scraping of the film on the outer surface. There was no problem in the adhesion between the wound portion and the neck portion, and the storage test was good.

Experimental Example 10 A biaxially stretched film of isophthalic acid copolymerized polyethylene terephthalate having a melting point of 225 ° C. having a constitution shown in Experimental Example 9 in Table 1 (stretching ratio: 3.0 times, width: 3.times.) Was formed on the surface to be the outer surface.
0 times, heat setting temperature 170 ° C.), and a biaxially stretched polyethylene naphthalate / polyethylene terephthalate copolymer film having a melting point of 205 ° C. (stretching ratio 3.0 times, 3.0 times width) The heat setting temperature was 160 ° C.), except that the plate temperature was 210 ° C. and the laminating roll temperature was 80 ° C., thereby obtaining a laminated plate in the same manner as in Experimental Example 1. This laminated plate was processed in the same manner as in Experimental Example 5 to obtain a seamless can for 350 g. Immediately after the continuation, the outer surface film was scraped, and a continuous can was not made. Delamination and film cracking occurred at the end of the flange of the can after the can-making, and it was judged that the can was unsuitable for practical use.

Experimental Example 11 A biaxially oriented film of isophthalic acid copolymerized polyethylene terephthalate having a melting point of 225 ° C. and a constitution shown in Experimental Example 10 in Table 1 was drawn at a plate temperature of 260 ° C. and on a surface to be an outer surface (stretching ratio of 3. A laminate was obtained in the same manner as in Experimental Example 1 except that 0 times, 3.0 times width, and heat setting temperature of 160 ° C. were used. This laminated plate was processed in the same manner as in Experimental Example 5 to obtain 350
g seamless cans were obtained. The heat treatment of the cup was performed at 150 ° C. Immediately after the continuation, fine shavings occurred on the outer film, and from about 10,000 continuous times, the outer film was frequently shaved, and stable continuous can-making properties could not be obtained. In the retort heat sterilization treatment after filling the contents, a film crack occurred in the tightened portion. In the storage test, corrosion occurred in the tightened portion one day after the lapse of time, and cracks occurred in the bottom of the can from one week after the lapse of time, leading to corrosion. From these results, it was determined that the composition was not suitable for practical use.

EXPERIMENTAL EXAMPLE 12 A sheet temperature of 200 ° C. and a laminating roll temperature of 80 ° C. were applied to a surface to be an outer surface.
Polyethylene naphthalate / polyethylene terephthalate copolymer biaxially stretched film at 20 ° C. (stretch ratio 3.5
And a width of 3.6 times, a heat setting temperature of 160 ° C.), and a biaxially stretched polyethylene naphthalate / polyethylene terephthalate copolymer having a melting point of 205 ° C. (stretching ratio: 3.0 times, width: 3.0 times, heat setting temperature 16
(0 ° C.) A laminate was obtained in the same manner as in Experimental Example 1 except that 25 μm was used. This laminated plate was processed in the same manner as in Experimental Example 5 to obtain a seamless can for 350 g. Immediately after can making, the can was broken and continuous can was not made.

Experimental Example 13 When the laminating roll temperature was 60 ° C. and the passing speed was 40 m / min,
The film on the surface to be the outer surface was polybutylene terephthalate 3 having a melting point of 235 ° C. and having the structure shown in Experimental Example 13 in Table 1.
Laminating was performed in the same manner as in Experimental Example 1 except that a biaxially stretched isophthalic acid copolymerized polyethylene terephthalate film (stretching ratio: 3.5 times, width: 3.6 times, heat setting temperature: 200 ° C.) containing 0% by weight was used. I got a board. This laminated plate was processed in the same manner as in Experimental Example 8 to obtain a seamless can for 250 g. The heat treatment of the cup was performed at 180 ° C. The film was scraped from about 10,000 continuous. Fine delamination and film cracking occurred on the flange portion of the can made. In the storage test, corrosion occurred from the flange portion to the neck portion, and cracking occurred at the dent portion at the bottom of the can, and corrosion occurred from that portion. From these results, it was determined that the composition was not suitable for practical use.

Experimental Example 14 Same as Experimental Example 11 except that a biaxially stretched film of isophthalic acid copolymerized polyethylene terephthalate having the constitution shown in Experimental Example 13 in Table 1 was used on the surface to become the outer surface of the original plate having a thickness of 0.240 mm. To obtain a laminated plate. This laminated plate was processed in the same manner as in Experimental Example 8 to obtain a seamless can for 200 g. The heat treatment of the cup was performed at 240 ° C. From about 50,000 cans continuously, the outer surface film was frequently scraped, and a stable can-making state could not be obtained. In the storage test, under-film corrosion occurred at the neck and bottom dents. In addition, it was determined that the appearance of the can was not suitable for practical use.

Experimental Example 15 The original plate thickness was 0.205 mm, the plate temperature was 190 ° C., and the passing speed was 40.
m / min., except that a cast film of isophthalic acid copolymerized polyethylene terephthalate having a melting point of 235 ° C. and a constitution shown in Experimental Example 14 of Table 1 and Table 2 prepared in advance on the surface to be the outer surface was used. A laminate was obtained in the same manner as in Experimental Example 8. This laminated plate was performed in the same manner as in the experimental example to obtain a seamless can for 250 g. Although 50,000 cans were made continuously, the can making condition was stable and the appearance of the can was not a problem, but delamination occurred in the flange portion after the heat treatment of the cup, and shrinkage of the film was observed. It was judged that it was not suitable for practical use. The birefringence of the upper part of the can in Tables 1 and 2 shows data before the heat treatment.

[0071]

[Table 1]

[0072]

[Table 2]

[0073]

According to the present invention, the resin film layer to be the outer surface or the inner surface of the can is formed by a two-layer structure of the surface resin layer (a) and the base resin layer (b), or the surface resin layer ( a), a three-layer structure of an intermediate resin layer (b) and a base layer (c), wherein the pigment content of the surface resin layer (a) or the base resin layer (c) is 20% by weight or less; The pigment content of the base resin layer to the intermediate resin layer (b) is 10 to 7
By adding 0% by weight of the pigment in the surface resin layer (a) or the base resin layer in an amount larger than the pigment content, the hiding power is improved. On the other hand, by setting the pigment content of the surface resin layer (a) to 20% by weight or less, it is possible to prevent the film from being scraped during drawing and ironing. In the case of the above-mentioned three-layer laminated structure, the base resin layer (c)
By adjusting the pigment content to 20% by weight or less, the adhesion and impact resistance of the laminated resin film can be improved. Furthermore, in the can-made laminate plate of the present invention,
A multilayer resin film containing a pigment in a specific ratio is laminated on a metal plate. The value of the birefringence (Δn) of the film portion of the base resin layer (b) or (c) in contact with the metal plate is set to 0 to 0.
1, which has succeeded in solving the above-mentioned problems and improving the adhesiveness by using a multilayer film containing a large amount of pigment by suppressing the birefringence of the surface side film portion to a value not more than the value. It is.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a cross-sectional structure of a laminated board for can making of the present invention.

FIG. 2 is a view showing another example of the cross-sectional structure of the laminated plate for cans of the present invention.

FIG. 3 is a diagram showing the relationship between the content of titanium dioxide and the strength of a film for a resin-coated metal plate.

FIG. 4 is a flowchart of a birefringence measurement method.

FIG. 5 is a diagram showing a thickness direction distribution of birefringence for an example of a laminate plate of the present invention.

FIG. 6 is a diagram showing a thickness direction distribution of birefringence in another example of the laminated plate of the present invention.

FIG. 7 is a view showing a thickness direction distribution of birefringence for an example of the coated seamless can of the present invention.

FIG. 8 is a view showing a thickness direction distribution of birefringence in another example of the coated seamless can of the present invention.

Continued on the front page F-term (reference) 3E033 AA07 BA07 BA17 BB05 BB08 CA14 CA20 FA01 4F100 AB01C AB03 AK01A AK01B AK01D AK01E AK42 BA05 BA06 BA10A BA10E CA13A CA13B CA13D CA13E EC03 GB16 JBY JJYYJN18

Claims (10)

[Claims] 1. A surface resin layer (a) having a pigment content of 20% by weight or less and a resin layer having a pigment content of 10 to 70% by weight and having a pigment content higher than that of the surface resin layer (a). (B) in a laminated plate obtained by laminating a resin film containing (a) and (b) on a metal plate, wherein the resin layer (b) of the laminated plate is present as a base layer and the birefringence of the film portion of the resin layer (b) in contact with the metal plate Laminate plate characterized in that the value of (Δn) is 0.1 or less and the value of birefringence of the film portion on the surface side is less than or equal to: Δn = nm−nt (1) nm is the maximum orientation of the film Nt is the refractive index in the thickness direction of the film. 2. A surface resin layer (a) having a pigment content of 20% by weight or less, and an intermediate resin having a pigment content of 10 to 70% by weight and a pigment content higher than that of the surface resin layer (a). In a laminated plate in which a resin film including a layer (b) and a base resin layer (c) having a pigment content of 20% by weight or less is laminated on a metal plate, a film portion of the resin layer (c) in contact with the metal plate Wherein the value of birefringence (Δn) is not more than 0.1 and not more than the value of birefringence of the surface-side film portion: where Δn = nm−nt (1) nm is the refractive index in the maximum orientation direction of the film, and nt is the refractive index in the thickness direction of the film. 3. The laminated plate for cans according to claim 1, wherein the value of the birefringence (Δn) of the laminated film surface side portion is 0.005 to 0.14. 4. A portion having a different birefringence value is present on the inner side in the thickness direction from the surface side of the laminated film, and the value of the birefringence (Δn) of the different portion is 0.02 to 0.14.
The laminate plate for a can according to any one of claims 1 to 3, wherein the laminate has a birefringence value of a film portion in contact with a metal plate and a birefringence value of a surface-side film portion or more. 5. A coated seamless can, obtained by drawing or ironing the laminated plate according to any one of claims 1 to 4. 6. The birefringence (Δn) value of the film portion in contact with the metal plate at the upper portion of the can side wall of the seamless can is not more than 0.1 and not more than the birefringence value of the film portion on the surface side. The coated seamless can according to claim 5, wherein Δn = nh−nt (2) where nh is the refractive index of the film in the direction of the can axis, and nt is the refractive index of the film in the thickness direction. 7. The birefringence (Δn) value of the portion on the film surface side of the upper portion of the can side wall of the seamless can is set to 0.1.
7. The thickness of claim 5, wherein the number is from 0.1 to 0.18.
A seamless can according to claim 1. 8. In the upper part of the side wall of the seamless can, there is a portion having a different birefringence value on the inner side in the thickness direction from the surface side of the film, and the birefringence (Δn) of the different portion is present.
Is in the range of 0.02 to 0.18, and is not less than the value of the birefringence of the film portion on the front side and the value of the birefringence of the film portion in contact with the metal. The coated seamless can according to any one of the above. 9. A birefringence peak near the film portion in contact with the metal plate in the upper portion of the side wall of the seamless can, and the peak value (Δn) is 0.02 to 0.1.
The coated seamless can according to any one of claims 5 to 8, wherein 10. The coating according to claim 5, wherein the can side wall portion is thinned to 30 to 90% of the original thickness of the laminated laminate plate during drawing or ironing. Seamless cans.