JP2707965B2 - 2-piece can with excellent impact resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an impact-resistant steel sheet which is formed by coating an organic resin film on at least a metal surface on the inner surface side of a can body before drawing and ironing or drawing and drawing. More specifically, it relates to a piece metal can, and more specifically, a two-piece can which is drawn and ironed with excellent impact resistance and adhesion of an inner surface coating in which an axially and plane-oriented polyester resin coating is disposed on the inner surface of the can and a stretch drawing. It relates to a processed two-piece can.

[0002]

2. Description of the Related Art Conventionally, a thermoplastic polyester film is thermally bonded to a metal material such as a steel plate, and the coated metal structure is drawn and ironed, so that a molecularly oriented polyester coating is adhered to the inner surface of the can. The drawn ironing can provided in the state is already known, for example, as described in Japanese Patent Application Laid-Open No. 60-172637. However, the cans described in these documents do not have sufficient impact resistance, so if the contents are filled and then subjected to an impact during transportation or dropped in a carton, the inner surface of the can is covered. Cracks occur in the polyester-based organic resin coating that is in place, and the metal substrate comes into direct contact with the contents.
There were problems such as corrosion of the metal, perforation and leakage of the contents. Therefore, there has been an increasing demand for cans that do not crack the polyester-based organic resin coating on the inner surface of the can even if they are impacted during transportation or fall in a carton.

[0003]

The above-mentioned Japanese Patent Application Laid-Open No. Sho 60-1
No. 72637 proposes to provide a polyester coating having a molecular orientation on the inner surface coating, that is, a polyester with the C-axis of the oriented crystal being axially oriented, in close contact with the inner surface of the can. But,
Even with such a coating, if the normal of the (100) plane of the crystal in which the C axis present on the can wall is oriented in a random direction, the structure becomes similar to the fibrous structure. It was clarified that the resin film cracked parallel to the C axis when subjected to an impact. Unless this problem is solved, the impact resistance of the can is not improved.

[0004] In order to solve this problem, various studies have been made, and the inventor of the present invention has found that the resin for coating the inner surface of the can body has an intrinsic viscosity (I).
V) using a polyester resin having a value of 0.60 or more, and controlling a parameter A representing the degree of the C-axis of the oriented crystal in the polyester resin film in the can height direction to 0.40 or more; By controlling the parameter B, which represents the proportion (plane orientation degree) of the (100) plane of the oriented crystal in which the C axis is axially oriented in the can height direction in parallel with the resin coating surface, is controlled to 0.00 or more. It was clarified that it was effective in improving impact resistance and corrosion resistance, and the problem was solved.

[0005]

Means for Solving the Problems The present invention provides a two-piece metal can which is obtained by first coating an organic resin film on at least the metal surface on the inner side of the can body and then drawing and ironing or drawing and drawing. The organic resin film is mainly composed of a polyester resin containing oriented crystals, and the polyester resin layer has an intrinsic viscosity (IV) of 0.6.
0 or more, a parameter A representing the degree of axial orientation of the oriented crystal in the can height direction is A ≧ 0.40, and a parameter representing the degree of plane orientation of the crystal that is axially oriented in the can height direction. B is a two-piece metal can excellent in impact resistance of the can body, wherein B ≧ 0.00. 2. Parameter A is a parameter indicating the degree of existence of crystals in which the C axis is axially oriented in the height direction of the can among the oriented crystals in the polyester resin film, and the two-piece metal having excellent impact resistance described in 1 above can. 3. Parameter B is a parameter indicating the degree to which the (100) plane of the oriented crystal in which the C axis in the polyester resin film is axially oriented in the height direction of the can is parallel to the resin film. 2-piece metal can with excellent impact properties. About.

[0006]

The axial orientation parameter A and the plane orientation parameter B of the axially oriented crystal, which are one of the features of the present invention, will be described.

[0007] Parameter A is a crystal in which the C axis is axially oriented in the height direction of the can among the crystals in the polyester resin coating on the can wall where the C axis is parallel to the film surface. Represents the degree of existence (degree of axial orientation).

[0008] Parameter B represents the degree of plane orientation of crystals axially oriented in the can height direction in the polyester resin coating on the can wall. Parameter B in the present invention
Has a different meaning from the plane orientation degree obtained by ordinary measurement. The degree of plane orientation usually measured is not only about the oriented crystal whose C axis is oriented in the height direction of the can, but also on the film surface.
0) The plane orientation degree includes all plane-oriented crystals parallel to each other, but the parameter B is such that among the crystals which are axially oriented in the can height direction, the (100) plane is parallel to the film surface. This indicates the degree of existence of the oriented crystal.

In the present invention, the presence state of the (-105) plane in which the normal line is inclined by about 8 to 10 degrees with respect to the C axis of the oriented crystal is measured for the polyester resin film.
The degree of plane orientation of the (100) plane of the crystal whose C axis is axially oriented in the height direction of the can is measured. Both the PET-based crystal and the PBT-based crystal are triclinic, and the C-axis is inclined by about 8 degrees and about 10 degrees with the normal to the (-105) plane, respectively.

The parameter B will be described using an example of a PET crystal. The C-axis of the oriented crystal is axially oriented in the height direction of the can, the [100] direction is in the direction of the upper surface of the resin film, and (1
When the (00) plane exists parallel to the resin coating surface (plane oriented), the diffraction peak in the X-ray diffraction measurement shown in FIG.
Degrees, about 278 degrees. On the other hand, the C axis of the oriented crystal is axially oriented in the height direction of the can, the [100] direction is on the lower surface side of the resin film, and the (100) plane exists parallel to the resin film surface (plane orientation). ), The diffraction peak appears at a position at a rotation angle of about 82 degrees and about 262 degrees.

Therefore, in the X-ray diffraction measurement shown in FIG. 2, diffraction peaks appear at about 82 degrees and about 98 degrees near 90 degrees, and at about 262 degrees and 278 degrees near 270 degrees. Is that the C axis is axially oriented in the can height direction, the [100] direction is in the direction of the upper surface of the resin coating, and (1)
The (00) plane is oriented crystal parallel to the resin coating surface, the C axis is axially oriented in the can height direction, the [100] direction is on the lower side of the resin coating, and the (100) plane is the resin coating. This is due to the presence of oriented crystals that are parallel to the plane.

On the other hand, even when the C-axis is axially oriented in the height direction of the can, the (100) plane is not parallel to the resin coating surface and is oriented in a random direction. In the case of not being oriented, the X-ray diffraction measurement shown in FIG.
One diffraction peak near 0 degree and about 270 degree appears without separation. That is, as the degree of plane orientation of the crystal axially oriented in the can height direction increases, the separation of peaks near 90 ° and 270 ° increases. As described above, the X-ray diffraction measurement shown in FIG.
Diffraction peak shape near 0 degree and 270 degree (separation state)
It is clear from the above that the parameter B defined in the present invention represents the degree of plane orientation of crystals axially oriented in the height direction of the can in the polyester resin film.

In the present invention, a polyester resin having an intrinsic viscosity of 0.60 or more is used for the body of the can, and a parameter indicating the degree to which the C axis of the oriented crystal in the polyester resin film is axially oriented in the height direction of the can. A is controlled to 0.40 or more, and (10) of the oriented crystal in which the C axis is axially oriented in the can height direction.
0) Ratio of plane parallel to resin coating surface (plane orientation degree)
By controlling the parameter B representing 0.00 or more to 0.00 or more, the impact resistance and corrosion resistance of the polyester film of the can were significantly improved. The Examples and Comparative Examples clearly show that the intrinsic viscosity (IV) and the parameters A and B of the polyester resin used must be within the ranges specified in the present invention.

The metal plate used in the present invention has a thickness of 0.1 to 1.0 mm, and the types of metal include tin-plated steel plate, TFS, Ni-plated steel plate, Al-plated steel plate, pure aluminum plate, Aluminum alloy plates can be suitably used.

As the crystalline polyester resin which is a main component of the resin of the present invention, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and copolymers and blends thereof are used. The copolymer component of the copolymerized polyethylene terephthalate may be an acid component or an alcohol component. Examples of the acid component include aromatic dibasic acids such as isophthalic acid, phthalic acid and naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and decane dicarboxylic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. Acids and the like,
Examples of the alcohol component include aliphatic diols such as butanediol and hexanediol, and alicyclic diols such as cyclohexanedimethanol. These can be used alone or in combination of two or more. These crystalline polyesters can be used as a single layer or as two or more layers.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a method for manufacturing a two-piece metal can according to the present invention will be briefly described.

Example 1 A crystalline polyester resin whose main component is an intrinsic viscosity of 0.60 or more is heat-coated on a metal plate and then quenched to obtain a polyester resin-coated metal plate having a crystallinity of 10% or less. The total drawing ratio is 1.5 with the surface as the inner side of the can.
Efficient production by drawing in the above manner, then ironing to a total reduction of 15% or more, and then heat-treating at a temperature not higher than the melting point of the polyester resin, which is the main component of the resin coating layer, by 60 ° C. You can do it.

Example 2 A crystalline polyester resin whose main component is an intrinsic viscosity of 0.60 or more was heat-coated on one or both surfaces of a metal plate and then quenched to obtain a polyester resin-coated metal plate having a crystallinity of 10% or less. After that, the drawing is performed with the resin-coated surface as the inner surface of the can with a total drawing ratio of 1.5 or more and a total reduction of 20% or more, and then 60 ° C. lower than the melting point of the polyester resin that is the main component of the resin coating layer. By performing the heat treatment in a temperature range not exceeding the melting point from the temperature, it is possible to efficiently manufacture.

Next, the present invention will be described in detail with reference to examples. Throughout the examples and comparative examples, the measurement of the crystallinity and intrinsic viscosity (IV) of the polyester resin, the calculation of the reduction, and the measurement of the parameters A and B were performed as follows.

1. Measurement of Crystallinity and Intrinsic Viscosity (IV) of Polyester Resin The measurement of crystallinity of crystalline polyester resin is described in the literature (S
EN-I GAKKAIISHI, Vol. 33, no.
10 (1977), 780-). That is, the X-ray diffraction scattering intensity distribution was separated into contributions from a crystal phase and an amorphous phase, and calculated as an integrated intensity ratio with respect to the Bragg angle. The intrinsic viscosity (IV) of the crystalline polyester resin was measured by peeling the resin layer on the inner surface of the can body from the metal plate and then measuring the o-
Measured in chlorophenol at 25 ° C.

2. Calculation method of reduction Reduction was calculated as follows. Reduction = (thickness of original sheet-thickness of can body) x 100 / thickness of original sheet

3. Measurement of parameters A and B Measurement was performed according to the following procedure. The polyester resin film is peeled from the center of the can body, and the peeled resin film is set on the X-ray diffractometer by a transmission method (at this time, X = 2θ = 0 degree X
The release resin film is set to be perpendicular to the line incident beam). Next, the X-ray diffraction angle 2θ was changed to the diffraction angle of 42.9 degrees (PB
In the case of a T-based polyester resin, it is set to 2θ = 39.0 degrees). The release resin film is rotated at a rate of 0.5 ° / sec from 0 to 360 ° with the film normal on the X-ray diffraction measurement surface as the axis, and the horizontal axis represents the rotation angle and the vertical axis represents the X-ray diffraction under the following X-ray diffraction conditions. An (-105) X-ray diffraction intensity curve as intensity is obtained. Here, the rotation angles 0 and 180 degrees correspond to the circumferential direction of the can, 90 degrees to the can bottom direction, and 270 degrees to the can height direction.

X-ray diffraction conditions Target: Cu, tube voltage 40 Kv, tube current 40 m
A, divergence slit: 1 °, detection slit: 0.3 mm, Next, an X-ray diffraction intensity curve is obtained in the same manner as above, except that the X-ray diffraction angle 2θ is set to 45.0 degrees. This is the background. By subtracting the X-ray diffraction curve at 2θ = 45.0 degrees from the X-ray diffraction intensity curve at 2θ = 42.9 degrees (PBT type X-ray diffraction intensity curve at 2θ = 39.0 degrees), (−− 105) Obtain a diffraction intensity curve of the crystal plane (FIG. 1). Parameter A is defined as follows (FIG. 1). X: Total area of (-105) plane strength at a rotation angle of 0 to 360 degrees Y: Total area of a range area of a rotation angle of 90 ± 30 degrees and a range area of 270 ± 30 degrees A = Y / X

The parameter A indicates the degree of the crystal in which the C axis is oriented in the height direction of the can among all the crystals of the PET crystal having the C axis parallel to the film surface. That is, it indicates the degree of axial orientation of the PET crystal in the height direction of the can.

In the case of PET resin, parameter B is
It is defined as follows. At around 90 ° in FIG. 2, C1, D1, and E1 are obtained as follows, and H1 and W1 are calculated.
Obtain the parameter B1. C1: The largest strength in the range of 98 ± 2 degrees (the largest strength in the range of 100 ± 2 degrees in the case of the PBT resin) D1: The largest strength in the range of 82 ± 2 degrees (PBT resin In the case, the largest strength in the range of 80 ± 2 degrees) E1: The smallest strength in the range of 90 ± 2 degrees (the same applies to the PBT resin) H1 = (C1 + D1) / 2 W1 = H1-E1 B1 = W1 / H1 Similarly, at around 270 degrees in FIG.
2, H2 and W2 are determined, and parameter B2 is determined. C2: The largest intensity in the range of 278 ± 2 degrees (PBT
D2: The largest strength in the range of 262 ± 2 degrees (PBT)
E2: The smallest strength in the range of 270 ± 2 degrees (PBT)
H2 = (C2 × D2) / 2 W2 = H2-E2 B2 = W2 / H2 Then, the average of B1 and B2 is calculated as the parameter B of this can body.
And Parameter B indicates the degree of the crystal whose plane orientation (the (100) plane is parallel to the film surface) among crystals whose C axis is oriented in the direction of the can height. B increases when there are many plane-oriented crystals. Throughout the examples and comparative examples, each test was performed as follows.

Can side wall impact resistance test The prepared drawn ironed can, drawn drawn can or drawn can or drawn can is filled with Coca-Colalite (trade name of Nippon Coca-Cola Co., Ltd.) at a low temperature and coated with an aluminum lid. After being stored at room temperature for 5 days and then stored at 5 ° C for 2 days, a right-angled block having a weight of 700 g is placed at a temperature of 5 ° C directly below the neck start point of the can body and at the center of the can wall at a height of 50 mm.
The can body is subjected to shock deformation by dropping it from the container. After storing at 5 ° C. for 2 days, the can is opened, and the impact deformation part of the can body is subjected to current measurement. X was evaluated. In the energization measurement, a sponge containing a 1% NaCl solution was brought into contact with the impact deforming portion, a voltage of 6.0 V was applied between an electrode (cathode) in the sponge and the can body, and a flowing current was measured.

Transport Test After making cans and filling the contents (Coca-Colalite) in the same manner as for the evaluation of the impact resistance to the side wall of the cans , put them in a cardboard box containing 24 cans, and reciprocate them by truck cargo service. 100km
Transport test. Each type was tested in 10 boxes (240 cans). After the transport test, after storing at 37 ° C. for one year, the can was opened and the amount of iron eluted in the contents was analyzed by an atomic absorption method. Also, the state of corrosion of the inner surface of the can of the deformed can body received by transportation was observed. The iron elution amount indicates the average value of 240 cans.

Example 1-1 A crystalline polyester resin (polyethylene terephthalate / polyethylene terephthalate) having a thickness of 30 μm and an IV of 0.85 was coated on one side of a 0.245 mm thick, temper 4, E2.8 / 2.8 tinplate. (Isophthalate-based) and quenched. Table 1 shows the crystallinity of the resin after coating. Using this one-sided resin-coated tin-plated steel sheet, the resin-coated surface is blanked to a diameter of 142 mm so that the resin-coated surface is the inner surface of the can, a cup is formed at the first drawing ratio of 1.6, and then redrawn (2nd drawing ratio of 1.3). ) And ironing (3 steps, total reduction 67)
%) To form a drawn and ironed cup having an inner diameter of 65.8 mm. This squeezed ironing cup can be 123mm in height
After trimming, washing and drying, heating temperature 21
0 ° C (21 ° C lower than the melting point of polyester resin) 2
Processed in minutes. Thereafter, printing and baking were performed on the outer surface, the upper part of the can was reduced in diameter to 57.25 mm, and a flange was formed. About the can body of this can, I
V and parameters A and B were measured, and a can side wall impact resistance test and a transport test were performed. Table 1 shows the results.

Example 1-2, Comparative Examples 1-1, 1-2 In Example 1-2, the organic resin film coated on the tin-plated steel sheet was an isophthalic acid-based copolymerized PBT, and the resin IV was 0.71. Except that X-ray diffraction angle 2θ was 39.0 degrees, and parameters A and B were changed in the same manner as in Example 1-1. Measurement was performed, and a can side wall impact resistance test and a transport test were performed. Table 1 shows the crystallinity after the resin coating and the test results. The heating temperature of 200 ° C. after washing and drying is a temperature 12 ° C. lower than the melting point of the polyester resin.

In Comparative Example 1-1, a drawn and ironed can was manufactured in the same manner as in Example 1-1 except that a thermosetting resin having a thickness of 5 μm was applied to one side (inner side) of the tin-plated steel sheet and then baked. Can, and the parameters A and A were obtained in the same manner as in Example 1-1.
B was measured, and a can side wall impact resistance test and a transport test were performed. Table 1 shows the test results.

Comparative Example 1-2 is the same as Example 1-1 except that the resin to be thermally coated is a polyester resin having no thermal crystallinity (polyethylene terephthalate / isophthalate).
In the same manner as in Example 1, a drawn and ironed can was made, IV and parameters A and B were measured in the same manner as in Example 1-1, and a can side wall impact resistance test and a transport test were performed. Table 1 shows the crystallinity after the resin coating and the test results.

Examples 2-1, 2-2, 2-3, Comparative Example 2
-1, 2-2 Examples 2-1 2-2, 2-3, Comparative Examples 2-1 2-2
By changing the IV of the resin to be coated, the IV of the organic resin coating on the inner surface of the can is 0.74, 0.66,
A drawn and ironed can was prepared in the same manner as in Example 1-1 except that the values were changed to 0.60, 0.58, and 0.55.
IV and parameters A and B were measured in the same manner as in Example 1, and a can side wall impact resistance test and a transport test were performed. Table 1 shows the crystallinity after the resin coating and the test results. The heating temperature after washing and drying was 210 ° C., 21 ° C., 23 ° C., 25 ° C. and 26 ° C., respectively, from the melting point of the polyester resin used.
° C, 27 ° C, low temperature.

Example 3-1 A biaxially stretched crystalline polyester resin (polyethylene terephthalate) having a thickness of 30 μm and an IV of 0.85 was coated on one surface of a 0.245 mm thick, temper 4, E2.8 / 2.8 tinplate. / Isophthalate type), and after quenching after adjusting the holding time at 230 ° C. so that the crystallinity of the polyester resin of the laminate plate (before molding) was 5%. A drawn and ironed can was obtained in the same manner as in Example 1-1, except that this one-sided resin-coated tin-plated steel sheet was used. The IV and parameters A and B of the can body were measured, and a can side wall impact resistance test and a transport test were performed. Table 1 shows the results.

Comparative Examples 3-1 and 3-2 Comparative examples 3-1 and 3-2 were the same as the examples except that the crystallinity of the polyester resin of the laminated plate (before molding) was 15% and 24%, respectively. A drawn and ironed can was prepared in the same manner as in 3-1. IV and parameters A and B were measured in the same manner as in Example 3-1. A can side wall impact resistance test and a transport test were performed. Table 1 shows the crystallinity after the resin coating and the test results.

Example 4-1 A crystalline polyester resin (polyethylene terephthalate / polyethylene terephthalate / polyester) having a thickness of 30 μm and an IV of 0.85 was coated on one side of a 0.245 mm thick, temper 4, E2.8 / 2.8 tinplate. (Isophthalate-based), and after the holding time at 210 ° C. was adjusted so that the crystallinity of the polyester resin of the laminated plate (before molding) was 10%, the mixture was quenched. A drawn and ironed can was obtained in the same manner as in Example 1-1, except that this one-sided resin-coated tin-plated steel sheet was used. The IV and parameters A and B of the can body were measured, and a can side wall impact resistance test and a transport test were performed. Table 1 shows the results.

Comparative Example 4-1 Comparative Example 4-1 is similar to Example 4 except that the crystallinity of the polyester resin of the laminate (before molding) is 18%.
In the same manner as in Example 1, a drawn ironing can was prepared, and the IV and parameters A and B were measured in the same manner as in Example 4-1 to perform a can side wall impact resistance test and a transport test. Table 1 shows the test results.
Shown in

Example 5-1 A crystalline polyester resin (polyethylene terephthalate / polyethylene terephthalate / polyethylene terephthalate) having a thickness of 17 μm and an IV of 0.85 was coated on one side of a 0.245 mm thick, temper 4, E2.8 / 2.8 tinplate. (Isophthalate-based) and quenched. Table 1 shows the crystallinity of the resin after coating. Using this one-sided resin-coated tin-plated steel sheet, the resin-coated surface is blanked to a diameter of 142 mm so that the resin-coated surface is the inner surface of the can, a cup is formed at the first drawing ratio of 1.6, and then redrawn (2nd drawing ratio of 1.3). ) And ironing (3 steps, total reduction 40)
%) To form a drawn and ironed cup having an inner diameter of 65.8 mm. The squeezed ironing cup was trimmed so that the can height became 60 mm, washed and dried, and then heated at a heating temperature of 210 mm.
C. (a temperature 21 ° C. lower than the melting point of the polyester resin) for 2 minutes. Thereafter, outer surface printing and printing were performed, the upper part of the can was reduced in diameter to 63.5 mm, a flange was formed, and a drawn ironed can was obtained. The IV and parameters A and B of the can body were measured, and a can side wall impact resistance test and a transport test were performed. Table 1 shows the results.

Example 5-2, Comparative Examples 5-1 and 5-2 In Example 5-2, the thickness of the heat-coated resin was 13 μm.
A drawn ironing can was produced in the same manner as in Example 5-1 except that ironing was performed in two steps, the total reduction was 20%, and the trim height was 50 mm. Parameters A and B were measured, and a can side wall impact resistance test and a transport test were performed. Table 1 shows the crystallinity after the resin coating and the test results. Comparative Example 5-1 was drawn in the same manner as in Example 5-1 except that the thickness of the heat-coated resin was 11 μm, the ironing was performed in one step, the total ironing rate was 10%, and the trim height was 40 mm. An ironed can was prepared, IV and parameters A and B were measured in the same manner as in Example 5-1, and a can side wall impact resistance test and a transport test were performed. Table 1 shows the crystallinity after the resin coating and the test results. Comparative Example 5
-2, the thickness of the heat-coated resin is 10 μm, there is no ironing process, and only drawing is performed, and a drawn can is produced in the same manner as in Example 5-1 except that the trim height is 40 mm. IV and parameters A and B were measured in the same manner as in Example 5-1 to perform a can side wall impact resistance test and a transport test. Table 1 shows the crystallinity after the resin coating and the test results.

Examples 6-1 and 6-2, Comparative Examples 6-1 to 6
-3 Examples 6-1 and 6-2, Comparative Examples 6-1 and 6-2 and 6-3
The heat treatment after washing and drying was performed at 210 ° C. (a temperature 21 ° C. lower than the melting point of the polyester resin) for 0.5 minute and 18 minutes, respectively.
0 ° C (Temperature 51 ° C lower than the melting point of polyester resin) 2
Example 1 except that the temperature was 100 ° C. (temperature 131 ° C. lower than the melting point of the polyester resin) for 2 minutes, and none was 250 ° C. (temperature 19 ° C. higher than the melting point of the polyester resin) for 2 minutes.
In the same manner as in Example 1, a drawn and ironed can was prepared.
IV and parameters A and B were measured in the same manner as described above, and a can side wall impact resistance test and a transport test were performed. Table 1 shows the crystallinity after the resin coating and the test results.

Example 7-1 Amorphous crystalline polyester resin (polyethylene terephthalate / isophthalate) having a thickness of 14 μm and an IV of 0.85 on one surface of 0.245 mm thick, temper 4 and TFS, and printing on the other surface The resulting mixture was heat-coated with a 14 μm-thick amorphous crystalline polyester resin (polyethylene terephthalate / isophthalate system) and quenched. Table 1 shows the crystallinity of the can inner surface side resin after coating. Using this double-sided resin-coated TFS, the printing surface is the outer surface,
After blanking to a diameter of 142 mm, forming a cup by first stretching and drawing (drawing ratio 1.6), performing 2nd drawing and drawing (drawing ratio 1.3, total reduction 30%), and drawing a drawn cup with an inner diameter of 65.8 mm Molded. The drawn draw cup was trimmed so that the can height became 50 mm. This cup was treated at a heating temperature of 210 ° C. (a temperature 21 ° C. lower than the melting point of the polyester resin) for 2 minutes. Thereafter, the upper portion of the can was reduced in diameter to 63.5 mm, and a flange was formed. IV and parameters A and B were measured for the resin on the inner surface of the can body of this can,
A can side wall impact resistance test and a transport test were performed. Table 1 shows the results.

Example 7-2 Example 7-2 was performed except that the thickness of the heat-coated resin was 13 μm, the film was stretched and drawn so that the total reduction was 20%, and the trim height was 50 mm. Example 7
In the same manner as in Example 1, a drawn drawn can was prepared.
IV and parameters A and B were measured in the same manner as described above, and a can side wall impact resistance test and a transport test were performed. Table 1 shows the crystallinity after coating the resin on the inner surface of the can and the test results.

[0042]

[Table 1]

(Note) The impact resistance in Table 1 was determined in accordance with the above evaluation method.
Indicates that it is 0.1 mA or more. A can of 0.1 mA or more has a practical problem. In the table, a to v are symbols meaning the following items. a Isophthalic acid-based copolymer PET b Thermosetting resin c Resin crystallinity d Can intrinsic viscosity (IV) e Evaluation parameter (*: no peak) f Crystallinity (%) after lamination (before processing) g Orientation Crystal h Thermal crystal j Drawing ironing k Drawing drawing m Reduction (%) n Can wall impact resistance o Large molding defect p Corrosion state of can inner surface q No abnormality r Drilling s Pointy corrosion t Pitting corrosion u Iron elution amount (ppm) v Isophthalic acid copolymerized PBT

(Evaluation) Examples 1-1, 1-2, 2-1 to 2-3, 3-1 and 4-
1,5-1,5-2,6-1,6-2,7-1,7-2
It can be seen that the polyester resin on the inner surface of the can body is a crystalline polyester, and that the parameter A is 0.40 or more, the parameter B is 0.00 or more, and the IV is 0.60 or more, the can side wall impact resistance is good. . Comparative Examples 1-1 and 1-
According to 2, when the coating resin on the inner surface of the can body is non-crystalline even if the coating resin is a polyester resin, the polyester resin on the can wall does not become oriented crystal (parameters A and B).
It can be seen that even if the IV is 0.60 or more, the impact resistance is inferior. In addition, when the coating resin on the inner surface of the can body is a thermosetting resin, resin defects occur during drawing and ironing,
It turns out that it is unsuitable as a can. Comparative Examples 3-1 and 3-
From 2,4-1,5-1,5-2 and 6-3, the laminate resin is a crystalline polyester resin and the IV is 0.60
Even above, the parameter A falls below 0.40,
When the parameter B is less than 0.00, the impact resistance is poor. From Comparative Examples 2-1 and 2-2, even when the laminating resin is a crystalline polyester resin and the parameter A is 0.40 or more and the parameter B is 0.00 or more, the IV is less than 0.60 and the resistance is low. It can be seen that the impact properties are poor. From Comparative Examples 6-1 and 6-2, the laminate resin was a crystalline polyester resin and the parameter A was 0.4.
Even if the IV is 0.60 or more, the impact resistance is poor when the parameter B is less than 0.00.

[0045]

According to the present invention, a polyester resin film having a principal component having a specific intrinsic viscosity (IV), a specific degree of axial orientation, and a specific degree of plane orientation is provided on a metal surface on the inner side of the can body. This has the effect of significantly improving the impact resistance of the metal can.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction intensity diagram.

FIG. 2 is an X-ray diffraction intensity diagram.

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication // B65D 8/04 B65D 8/04 G

Claims (3)

(57) [Claims] 1. An organic resin film is coated on at least a metal surface on the inner side of a can body before drawing and ironing, or
In a two-piece metal can formed by drawing and drawing, the organic resin film is mainly composed of a polyester resin containing oriented crystals, and the intrinsic viscosity (IV) of the polyester resin layer is 0.60 or more, and The parameter A indicating the degree of axial orientation in the can height direction is A ≧ 0.40, and the parameter B indicating the degree of plane orientation of the crystal that is axially oriented in the direction of the can height is B ≧ 0.00 A two-piece metal can having excellent impact resistance of a can body. 2. The impact resistance according to claim 1, wherein the parameter A is a parameter indicating a degree of existence of crystals in which the C axis is axially oriented in the height direction of the can among the oriented crystals in the polyester resin film. Excellent 2-piece metal can. 3. The parameter B is (1) of an oriented crystal in which the C axis in the polyester resin film is axially oriented in the height direction of the can.
2. The two-piece metal can with excellent impact resistance according to claim 1, wherein the parameter is a parameter indicating a degree of the (00) plane existing parallel to the resin film.