GB2285952A - Metal sheet covered with polyester resin film for drawn and stretched formed can. - Google Patents
Metal sheet covered with polyester resin film for drawn and stretched formed can. Download PDFInfo
- Publication number
- GB2285952A GB2285952A GB9400928A GB9400928A GB2285952A GB 2285952 A GB2285952 A GB 2285952A GB 9400928 A GB9400928 A GB 9400928A GB 9400928 A GB9400928 A GB 9400928A GB 2285952 A GB2285952 A GB 2285952A
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- Prior art keywords
- metal sheet
- resin film
- polyester resin
- layer
- film
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
- B32B15/09—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising polyesters
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/02—Physical, chemical or physicochemical properties
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/18—Layered products comprising a layer of metal comprising iron or steel
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/20—Layered products comprising a layer of metal comprising aluminium or copper
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
- B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2311/00—Metals, their alloys or their compounds
- B32B2311/16—Tin
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2311/00—Metals, their alloys or their compounds
- B32B2311/20—Zinc
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2311/00—Metals, their alloys or their compounds
- B32B2311/22—Nickel or cobalt
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2311/00—Metals, their alloys or their compounds
- B32B2311/24—Aluminium
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2311/00—Metals, their alloys or their compounds
- B32B2311/30—Iron, e.g. steel
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2367/00—Polyesters, e.g. PET, i.e. polyethylene terephthalate
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2439/00—Containers; Receptacles
- B32B2439/40—Closed containers
- B32B2439/66—Cans, tins
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2439/00—Containers; Receptacles
- B32B2439/70—Food packaging
Landscapes
- Laminated Bodies (AREA)
Description
2285952 METAL SHEET COVERED WITH POLYESTER RESIN FILM FOR DRAWN AND
STRETCH FORMED CAN The present invention relates to a metal sheet covered with a polyester resin f ilm, used as a material for container for foodstuff or beverage. having excellent formability of said polyester resin film and excellent corrosion resistance after severe forming, wherein the planar orientation coefficient in the innermost layer of said polyester resin film. directly contacted with a surface of said metal sheet or indirectly contacted with a surface of said metal sheet by laying a thermosetting resin layer between said polyester resin film and said metal sheet. Is different from that in the outermost (the furthest from a surface of said metal sheet) layer of said laminated polyester resin film on said metal sheet.
This metal sheet covered with a polyester resin film is suitable for some applications in which excellent formability and excellent corrosion resistance after severe forming are required, especially for a drawn and stretch formed can having high can height Recently. a technique for the production of a drawn and stretch formed can (which is also called a drawn thin redrawn can, DTR can) has been developed. This DTR can has a characteristic in which an average decreased ratio in the thickness of the can wall is about 10 to 30 % to the original thickness of the employed metal sheet.
However. this DTR can is not widely used for foodstuff and beverage. because the precoated lacquer film is peeled off the surface of a metal sheet such as a tin free steel, or many cracks arise in coated lacquer film under severe forming such as drawn and stretch forming, even if the tin free steel having excellent lacquer adhesion is used as a film covering base metal sheet.
Recently, various methods for lamination of a polyester resin film on a metal sheet with or without adhesive shown in United States Patent Nos. 4, 517, 255 and 4. 614. 691. Laid-Open Japanese Patent Application No. Hei 1-249331 and Japanese Patent Application No. Hei 2-154098 have been developed as methods instead of lacquer coating.
United States Patent Nos. 4. 517. 255 relates to a process for lamination of a crystalline polyester resin film onto a metal sheet by heating said metal sheet above the melting temperature of said polyester resin film and thereafter immediately quenching the laminate. In this patent. the crystalline polyester resin fila is sufficiently adhered to the metal sheet with an amorphous non-oriented polyester resin layer which is formed due to the change of a part of the crystalline polyester resin film as a result of heating step. However. the polyester resin film laminated metal sheet according to this patent is not used for DTR can. because the obtained DTR can requires being heated at about 180 to 220 "C for curing the printing ink coated on the outside of the DTR can. and the amorphous nonoriented polyester resin layer is rapidly recrystallized and the recrystallized amorphous non-oriented polyester resin layer is lacking in the impact resistance. When the impact stress (due to such as falling from a shelf) is given to a can body from the outside of the can body. micro cracks arise in the polyester resin film at the pushed out area that is the reverse inside area of the canbody, and the corrosion of the exposed metal is generated in these area.
In addition. the upper limit of the planar orientation coefficient of the laminated polyester resin film is not defined in this patent. so in case that the planar orientation coefficient of the laminated polyester resin film is greater than 0. 150 (even if only in the outermost layer of the film) many cracks arise in the laminated polyester resin film under forming the laminate into a DTR can having high can height. Then. the laminate. according to United States Patent Nos. 4,517.255 can not be employed as a material for DTR can.
United States Patent 4, 614. 691. Laid-Open Japanese Patent Application No. Rei 1-249331 and Japanese Patent Application No. Bei 2-154098 relate to the lamination of a biaxially oriented polyester resin film precoated with a small amount of a resin containing in its molecular structure at least one radical such as epoxy radical onto a metal sheet heated to below or above the melting temperature of said polyester resin filin. In Laid-Open Japanese Patent Application No. Bei 1-249331 and Japanese Patent Application No. Hei 2-154098. the polyester resin film having specified characteristics is applied for the lamination to the metal sheet. However, in these applications many cracks arise in the laminated Polyester resin film under severe forming or the laminated polyester resin film is lacking in impact resistance because the planar orientation coefficient in the outermost layer of the Polyester resin film and the innermostjayer of the polyester resin film indirectly contacted with the sudace of the metal sheet by laying a resin layer between the polyester resin film and the metal sheet are not controlled within a preferable range.
Accordingly, it is the objective of the present invention to provide a metal sheet covered with a polyester resin film having excellent formability of the polyester resin film to said metal sheet and excellent corrosion resistance after severe forming which is applied for DTR can having high can height.
The objective of the present invention can be accomplished by controlling the planar orientation coefficients in the innermost layer of the polyester resin film directly or indirectly contacted with the surface of the metal sheet and the outermost layer in the laminated polyester resin film.
The metal sheet covered with the polyester resin film according to the present invention has excellent corrosion resistance after severe forming. Therefore. it is used for not only DTR can having high can height, but also deeply drawn can, DRI) can and ran ends where a tab for easy opening is attached. In these applications, the cans are exposed to hot steam for sterilization after being packed with foodstuff or beverage such as fruit juice, coffee drink, meat and fish. For example. fruit juice is packed in a can immediately after the sterili2ation at a temperature of 90 to 100 C. Coffee drink. meat or fish is sterilized in hot steam at above 100 C in a retort after being packed in a can. Furthermore, the metal sheet according to the Present invention can be used for screw cap and crown cap.
In these applications. color printing ink or lacquer coationg is often applied on the outside of these cans before or after forming. In these cases. the laminated polyester resin film in the present invention keeps excellent adhesion and excellent impact resistance. even after reheating for curing color printing ink or lacquer and subsequent treatment in hot water or hot steam.
In the present invention. it is preferable to use a Polyester resin film of which melting temperature is from 210 to 250 Q selected from the homopolyester resin. co-polyester resin and polyester resin blended - 1.- with at least above one kind of homo-polyester resin and/or co-polyester resin.
Preferably homo-polyester resin is polyethylene terephthalate or polybutylene terephthalate, and co-polyester is copolymer of ethylene terephthalate and ethylene isophthalate or that of butylene terephthalate and butylene isophthalate.
In the present invention. it is impossible to use non-oriented polyester resin film. because such a film has high friction coefficient to tools used for the production of DTR can and has poor permeability resistance to the corrosive content. Namely. the formability of the metal sheet covered with this film into the DTR can is remarkably poor and the DTR can which is packed with corrosive content is corroded in the relatively short storage period of time. In addition, as mentioned above, the impact resistance is lacking in this film, it can not be used for the DTR can.
Therefore. the use of a polyester resin film having a biaxially oriented structure and the control of the planar orientation coefficient of the innermost layer (Layer B) of the polyester resin film directly or indirectly contacted with the surface of the metal sheet and the outermost layer (Layer A) of the polyester resin film are indispensable in the present invention In some cases, additives such as antioxidant, stabilizer, pigment. antistatic agent and corrosion inhibitor are added during the manufacturing process of the polyester resin film used for the present invention.
The planar orientation coefficient defined as the degree of the orientation of Layer A or Layer B of the laminated polyester resin film is respectively determined in the following method. At first. the laminated polyester resin film is removed from the metal sheet by dipping the laminate into hydrochloric acid solution which only dissolves the metal sheet. After rinsing in water and drying the film, the refractive indexes in the lengthwise. the widthwise and the thickness directions of either side layer (Layer A and Layer B) of the polyester resin film are measured with a refractmeter. After that. the planar orientation coefficient is determined according to the following equation, respectively.
A=(bCA-D wh ere, A represents the planar orientation coefficient of the polyester resin film.
B represents the refractive index in the lengthwise direction of the polyester resin film.
C represents the refractive index in the widthwise direction of the polyester resin film, D represents the refractive index in the thickness direction of the polyester resin film.
The refractive indexes measured by the method described above show the average value within 5 gm from the outermost layer (of the either side of the resin film) in the polyester resin film used for the measurement of the refractive indexes. Therefore. it is possible to divide the planar orientation coefficient in Layer A from that in Layer B. Generally, in the production of the polyester resin film laminated metal sheet. the polyester resin film is laminated onto the metal sheet heated to about the melting temperature of said polyester resin film. Therefore. the planar orientation coefficient of the innermost polyester resin layer contacted with the heated metal sheet drops after lamination due to the disapperance of the biaxially oriented structure according to 6- the melting of the resin. Furthermore. when the metal sheet is heated to higher temperature. or the laminate is quenched in a shorter period of time immediately after the lamination. the more amount of heat applied in the metal sheet is conducted to the polyester resin film and the wore proportion of the biaxially oriented structure of the resin film disappear. and then the planar orientation coefficient of the laminated film more drops in accordance with the distance from the surface contacted with the metal sheet. Therefore. the planar orientation coefficient of the innermost polyester resin layer contacted with the surface of the heated metal sheet is the lowest value and it goes up in the polyester resin film with the distance from the contacted surface with the heated metal sheet. Additionally, using of the laminating roll 'heated to higher temperature (below the melting temperature of the polyester resin) similarly affects the disappearance of the biaxially oriented structure of the polyester resin film. Namely. the amount of heat applied to the metal sheet conducts to the laminating roll through the intermediation of the polyester resin film, however. the conduction of the heat is inhibited and considerable amount of heat is accumulated in the polyester resin film by heating of the laminating roll. and the more amount of heat is applied to the polyester resin film, and then the biaxially oriented structure of the polyester resin film more disappears. From the reason mentioned above, it is considered that the slope of the planar orientation coefficient is formed in the laminated polyester resin film and the gradient of the slope can be controlled by means of the temperature of the metal sheet and of the laminating roll, and the period of time between lamination and quenching.
In the present invention. when the planar orientation coefficient in Layer B of the laminated polyester resin film is below 0.000. a quite a few of the amorphous non-oriented polyester resin has been formed in the whole laminated polyester resin film. So. Yhen the laminate is made into DTR can and it is heated at about 180 to 220 C required for curing the printing ink applied on the outside of it, the amorphous non-oriented polyester resin in the film is rapidly recrystallized and the polyester resin film becomes apt to be cracked with impact. In addition, the amorphous non-oriented polyester resin layer does not have enough permeability resistance to corrosive content, the laminate covered with such a polyester resin film can not be used as raw material for DTR can.
The amount of amorphous non-oriented resin in the laminated polyester resin film is decreased with the increase of the planar orientation coefficient in Layer B and the adhesive strength of the laminated polyester resin film to the surface of the metal sheet is also decreased. When the planar orientation coefficient in Layer B is above 0. 100. the adhesion of the laminated polyester resin film to the surface of the metal sheet is not good enough to form the laminate into a DTR can and the laminated polyester resin film is peeled off the surface of the metal sheet under severe forming. The reason is that the amount of the amorphous non-oriented polyester resin. enough for the excellent adhesive strength but not more than enough for the poor impact resistance. has not been formed in the polyester resin layer directly or indirectly contacted with the metal sheet. Therefore. it is preferable in the present invention that the planar orientation coefficient in Layer B is kept in the range of 0. 000 to 0. 100, more preferably 0. 005 to 0.050.
It is not preferable in the present invention that the planar orientation coefficient in Layer A of the laminated polyester resin f ilin is below 0. 010, because considerable proportion of the biaxial orientated structure in the whole f ilm has been lost in the polyester resin film having such a low planar orientation coefficient measured in 8- Layer A. then the polyester resin f ilm laminated metal sheet can not uniformly be formed into a DTR can having high can height due to increase of the friction coefficient in Layer A to tools used for the production of the DTR can and the surface of the metal sheet of the polyester resin film laminated metal sheet is chapped by severe forming.
Furthermore. a DTR can made of the polyester resin film laminated metal sheet having such a low planar orientation coefficient of Layer A is remarkably corroded by corrosive content in a long storage period of time after being packed with corrosive content into it. because the permeability resistance of the whole laminated polyester resin film becomes poor with decrease in the planar orientation coefficient measured in Layer A. In addition, with decrease of the planar orientation coefficient measured in Layer A, the amount of the amorphous non-oriented polyester resin becomes rich in the whole polyester resin film, and then the susceptibility to the impact stress of the film becomes keen.
On the other hand, in case that the planar orientation coefficient in Layer A of the laminated polyester resin film is above 0. 150. many cracks arise in the laminated polyester resin film under forming the laminate into a DTR can having high can height. independent of the planar orientation coefficient of Layer B. because the biaxially oriented polyester resin film having such a high planar orientation coefficient can not extend well. Therefore. it is indispensable in the present invention that the planar orientation coefficient in Layer A is kept within a range of 0. 010 to 0. 150, preferably 0. 030 to 0. 120.
Furthermore. it is more preferable in the present invention that the planar orientation coefficient in Layer A is larger than that in Layer B in order to stably produce the metal sheet covered with the polyester resin film.
- 9 As described above. the metal sheet covered with the polyester resin film having the controlled planar orientation coefficient is excellent in formability, scratch resistance. corrosion resistance and impact resistance after severe forming. However. the actal substrate of the laminate may be corroded or the laminated polyester resin film inay be peeled off the surface of the metal substrate, when the laminate is in contact with more corrosive content. In such a case. the existence of a thermosetting resin (adhesive resin) layer between the polyester resin film and the metal sheet prevents the corrosion of the metal substrate because the permeability resistance of the thermosetting resin layer to corrosive content is remarkably superior to that of the thermoplastic polyester resin film. The known resin can he used as an adhesive in the present invention. however. it is more preferable to apply a thermosetting resin containing epoxy radical in molecular structure on the one side of the polyester resin film or on the at least one side of the metal sheet.
There are following main ideas for the production of the metal sheet according to the present invention.
1. Control of the planar orientation coef f icient in Layer B to 0. 000 to 0. 100 by laminating a biaxially oriented polyester resin film having the planar orientation coefficient of 0. 010 to 0. 150 onto a metal sheet heated to about melting temperature of said polyester resin film and by melting a part of said polyester resin film contacted with surface of said metal sheet.
2. Use of the same above mentioned biaxially oriented polyester resin film of which one side to be contacted with a metal sheet is precoated with a thermosetting resin in the same laminating manner described above.
3. Lamination of the same above mentioned biaxially oriented polyester resin film onto a metal sheet of which at least one side to be t contacted with said polyester resin film is precoated with a thermosetting resin in the sue laminating manner described above.
4. Use of a double-layered polyester resin film in the same laminating manner described above. Namely. the f ilm consists of an upper layer film (further from the surface of a metal sheet) having melting temperature of 210 to 250 C and a lower layer film (directly or indirectry contacted with the surface of said metal sheet) having melting temperature of 190 to 230 'C.
In the present invention, the surface of the employed metal sheet should be covered with a hydrated chromium oxide layer in order to obtain excellent adhesion of the laminated polyester resin film to the metal sheet. Therefore, the employed metal sheet should be selected from the group consisting of a tin free steel having a double layer composed of an upper layer of hydrated chromium oxide and lower layer of metallic chromium, a steel sheet plated with at least one of metal of tin. nickel and zinc and covered with a mono layer of hydrated chromium oxide or double layer described above thereon, and a sheet of an aluminium or an aluminium-alloy (containing manganese of 0.3 to 1.4 weight %. magnesium of 0. 7 to 4. 8 weight %, zinc of o. 24 to 0. 29 weight % and copper of 0. 16 to 0. 24 weight %) covered with a mono layer of hydrated chromium oxide. The Optimum range of the hydrated chromium oxide is 3 to 50 Mg/M2 as chromium. more preferably 7 to 25 mg/ml. If the amount of the hydrated chromium oxide is below 3 mg/m2 or above 50 Mg/22 as chromium. the adhesion of the laminated polyester resin film becomes noticiably poor in the severely formed area. In the view point of corrosion resistance after the forming and the adhesion of the laminated polyester resin film, it is preferable that the amount of the metallic chromium is 10 to 200 ing/ml, especially 50 to 150 mg/ma in a double layer of tin free steel or a steel sheet Plated with tin. nickel or zinc. in order to facilitate the high speed production.
In the present invention. the method for beating the metal sheet to the temperature of which the polyester resin film is laminated is not limited. llowever. f rom the standpoint of the continuous and steady production of the polyester resin f ilm laminated metal sheet according to the present invention at high speed. the conduction beating with a roll heated by induction heating. the induction heating and/or resistance heating is suitable because the metal sheet can rapidly be heated and the temperature of the heated metal sheet can easily be controlled. Furthermore. it is also preferable that the heating with rolles heated in hot steam can be used as an auxiliary method for preheating the metal sheet to be laminated.
The present invention is explained in fatther detail according to the following examples. These examples do not limit the scope of the invention.
Example 1
A biaxially oriented copolyester resin film having characteristics shown in (A) was laminated at 235 C on both sides of a tin free steel having a thickness of 0. 17 cm, a temper of DR-10. amount of hydrated chromium oxide of 14 mg/mz as chromium and amount of metallic chromium of 110 Mg/M2.
After the planar orientation coefficient in Layer A and Layer B of the copolyester resin film in the obtained copolyester resin film laminated metal sheet were determined according to the method as described in the detail description, the copolyester resin film laminated tin free steel was formed into DTR can having high can height under the following conditions (B) and then dome, neck-in and flange forming was applied in turn to the DTR can.
1 (A) Characteristics of the employed polyester resin film Thickness: 20 u m Composition of the polyester resin film Ethylene glycol: 100 mole % Terephthalic acid 88 mole % Isophthalic acid 12 mole Planar orientation coefficient 0.125 Melting temperature': 230 C (B) Conditions for forming into DTR can 1) Drawing process Diameter of blank: 187 mm Drawing ratio: 1.50 2) Redrawin process First redrawing ratio: 1.29 Second redrawing ratio: 1.24 Third redrawing ratio: 1.20 Radius in the corner of dies used for redrawing: 0. 4 mm Load for prevention of wrinkles in the drawing process: 6000 kg 3) Average decreased ratio in the thickness of DTR can body: -20 % to the thickness of the employed metal sheet Example 2
A coextruded biaxially oriented copolyester resin film having characteristics shown in (A) was laminated at 232 C on both sides of the same tin free steel used in Example 1. After the planar orientation coefficient of Layer A and Layer B of the laminated copolyester resin film were determined. the copolyester resin film laminated tin free steel was formed into DTR can under the same conditions as in Example 1- (A) Characteristics of the employed polyester resin film 1) Upper layer Thickness: 15 # m Composition of the resin film Ethylene glycol: 100 mole % Terephthalic acid 88 mole Isophthalic acid 12 mole Planar orientation coefficient Melting temperature: 230 'C 2) Lower layer : 0.122 Thickness: 5 jum Composition of the resin film copolyester resin 55 weight %, composed of Ethylene glycol: 100 mole % Terephthalic acid 94 mole Isophtbalic acid 6 mole % polybutylene terephthalate 45 weight Planar orientation coefficient: 0. 080 Melting temperature: 226 'C Example 3
A clear copolyester resin film having the same composition and planar orientation coefficient as in Example 1 and a white-colored copolyester resin film made of the same resin composition and in the same production manner as in Example 1 except that it was pigmented with 16 weight % of titanium dioxide were simultaneously laminated at 250 C on the either 1 1 side of the same tin free steel as in Example 1. After the planar orientation coefficient in Layer A and Layer B of the laminated clear copolyester resin film were determined, the laminate was formed into DTR can under the same conditions as in Example 1. (The side laminated with white-colored copolyester resin film was the outside of DTR can.) Example 4
The copolyester resin film having the same composition as in Example 1 which was precoated with 0. 5 g/m' of epoxy-phenolic resin was laminated at 245 C on both sides of the same tin free steel as in Example 1. After the planar orientation coefficient in Layer A and Layer B of the laminated copolyester resin film were determined. the laminate was formed into DTR can under the same condition as in Example 1.
Example 5
Both sides of an aluminium-alloy sheet OIS 3004) was coated with 0.3 g/M2 of the same epoxy-phenolic resin as in Example 4 and dried at 119 C. After that a clear coextruded biaxially oriented copolyester resin film as in Example 2 and the same white-colored copolyester resin film as in Example 3 were laminated at 230 C on the either precoated side of the auminium-alloy sheet. After the planar orientation in Layer A and Layer B of the laminated clear copolyester resin film were determined. the laminate was formed into DTR can under the same conditions as in Example 1 in which load for prevention of wrinkles in redrawing process was different from that in Example 1. (The side laminated with white-colored copolyester resin film was the outside of DTR can.) (B) Conditions for forming into DTR can which was different from that -15 in Example 1 Load for prevention of wrinkles in the drawing process: 2000 kg Comparative example 1 A polyetylene terephthalate film having a thickness of 25 go. planar orientation coefficient of 0. 165 and melting temperature of 260 C was laminated at 280 C on both sides of the same tin free steel as in Example 1. After the planar orientation coefficient in Layer A and Layer B of the laminated polyetylene terephthalate film were determined. the laminate was formed into DTR can under the same conditions as in Example 1.
Comparative example 2 The same copolyester resin f ilm used in Example 1 was laminated at 210 &C on both sides of the same tin free steel as in Example 1. After the planar orientation coefficient in Layer A and Layer B of the laminated copolyester resin film were determined, the laminate was formed into DTR can under the same conditions as in Example 1.
Comparative example 3 The same copolyester resin film used in Example 1 was laminated at 305 C an both sides of the same tin free steel as in Example 1. After the planar orientation coefficient in Layer A and Layer B of the laminated copolyester resin film were determined, the laminate was formed into DTR can under the same conditions as in Example 1.
The characteristics of the DTR cans in Example 1 to 5 and Comparative example 1 to 3 were evaluated in the following methods. after the degree 16 of the cracks arisen in the laminated polyester resin film and the degree of the peeling-off of the polyester resin film in the formed areas, especially in the upper wall part and neck-in and flange formed area. of the DTR can were evaluated with the naked eye. The results are shown inTable 1.
(1) Degree of the exposed metal surface of the inside of DTR can Degree of the exposed metal surface was evaluated according to a current value flown between an anode of the metal surface exposed - through the cracks in the polyester resin film of DTR can which was filled with the 3 % of sodium chloride solution and a cathode of a stainless steel rod inserted in said DTR can at the constant voltage of 6. 3 V.
(2) Resistance to hot steam Resistance to hot steam was evaluated according to the degree of the peelig-off of the laminated polyester resin film in the flange formed part of DTR can after the treatment of the obtained DTR can in hot steam having temperature of 125 C in a retort for 30 minutes.
(3) Heat resistance Beat resistance was evaluated according to the degree of the cracks in the laminated polyester resin film. the discoloration and the peeling-off of the laminated polyester resin film in the formed area of the third redrawn can after the heat treatment at 200 C corresponding to the temperature for curing of the printing ink to be coated on the outside of DTR can.
(4) Corrosion resistance Corrosion resistance was evaluated according tothe degree of the corrosion of the inside of DTR can which was filled with 3 % of acetic acid solution and then stored for 3 months at 50 'C. The degree of the corrosion was divided into 5 ranks evaluated with the naked eye, namely 5 was excellent. 4 was good. 3 was fair. 2 was poor and 1 was bad.
z Table 1
1 tlo 1 Emwle 1 Ex.-tple 2 Example 3 Example 4 EY.W 1 e 5 Coaparative tive cative auuple 1 aymple 2 example 3 Base metal Tin free steel Tin free steel Tin free steel Tin free steel M- alloy(3004) Tin free steel Tin free steel Tin he steel Plaw orientation Sirface to be Layer A R 125 Layer A ft = Layer A 0. n Layer A 0.125 [aver A 0. = Layer A a 165 Layer A 0.13 layer A CL 15 coefficient of inside of con Layer B 0. 125 Layer B a OW Laye r B R 125 Laye r B 0.0 layer B D. 080 Laver B 0.165 Layer B a 13 layer B OL n resin film polyester &afam to b A 0. 125 layer A a L2 Layer A - Layer A 0.125 layer A - Layer A 0. 165 Layer A 0.0 Layer A 0.15 be-fore lacmticn outside of can Laic r B 0 125 layer B Q OW layer B - Layer B 0.125 Layer B - Layer B 0.165 Layer B a M B CL 0 Planar orientaticn Irface to be Laye r A 0.01 Laye r A a 112 Layer A R 062 Law A 0373 Layer A 0.114 A 157 Layer A 0.119 Layer A a 005 coefficient of inside of can Liver B Q 041 Layer 8 Q 010 Layer B 0.011 layer B 0.018 layer B 11010 layer B 0.050 Layer B 0. 105 layer B a 000 resin film -Polyester after 1ion & to be layer A a 088 Layer A Q 109 layer A - Lmer A D.071 Layer A Layer A R 153 Layer A 0.117 layer A a 004 cutside of can Layer B 0.0 Layer B Q 009 [aver B - Laer B 0.015 Layer B - Layer B a 046 Layer B 0.103 Layer 3 0. ODO Cracks in f ilm Peeling off RmSh steel Formability into D1R can Good Ccod Good Ccod Good in Of film in rabm n-in pan Degree of c neW a (A) a 03 0.10 0 0.06 0 Rmly M1ge Valw 60 hsistance to hot stem Good Good Good Good Good Good Iwossible.to mlmte fiMt resistance Gocd Good Cccd Good Good becaise d peel ing-off of Cracim in f i lp film or ameamm of mw in f iin Corresion resistance 5 5 5 5 5 1 (Yetal 1 disclosed)
Claims (18)
1. A metal sheet coated on at least one side thereof with a coating comprising a polyester resin film, wherein the innermost layer of said resin film nearest the surface of said metal sheet has a planar orientation coefficient of 0.000 to 0.100 and the outermost layer of said resin film furthest from the surface of said metal sheet has a planar orientation coefficient of 0.010 to 0.150 in the laminated polyester resin film.
2. A metal sheet as claimed in claim 1 wherein said polyester resin film is in direct contact with said surface of said metal sheet.
3. A metal sheet as claimed in claim 1 comprising a layer of thermosetting resin between said metal sheet and said polyester resin film so that said surface of said metal sheet is in contact with one side of said layer of thermosetting resin and said innermost layer of said resin film is in contact with the other side.
4. A metal sheet as claimed in claim 3 wherein one side of said polyester resin film has been pre-coated with said thermosetting resin.
5. A metal sheet as claimed in claim 3 wherein one side of said metal sheet has been pre-coated with said thermosetting resin.
6. A metal sheet as claimed in any one of the preceding claims wherein both sides of said metal sheet are coated with a polyester resin film having a melting temperature of 210 to 2500C.
7. A metal sheet as claimed in any one of the preceding claims wherein at least one side of said metal sheet is coated with a white-coloured polyester resin film.
8. A metal sheet as claimed in claim 7 wherein said white-coloured polyester resin film is pigmented with 2 to 20 weight % of titanium dioxide.
9. A metal sheet as claimed in any one of the preceding claims wherein the planar orientation coefficient in the outermost polyester resin layer in the laminated polyester resin film is larger than that in the innermost polyester resin layer.
10. A metal sheet as claimed in any one of claims 1 to 3 wherein said polyester resin film is a double-layered film consisting of an upper layer film having a melting temperature of 210 to 2500C and a lower layer film nearest the surface of said metal sheet having a melting temperature of 190 to 2300C.
11. A metal sheet as claimed in any one of claims 2 to 9, wherein said thermosetting resin contains in its molecular structure at least one radical selected from the group consisting of an epoxy radical, a hydroxyl radical, an amide radical, a carboxyl radical, a urethane radical, an acryl radical and an amino radical.
12. A metal sheet as claimed in any one of the preceding claims wherein said metal sheet has a double layer consisting of an upper layer of hydrated chromium oxide and a lower layer of metallic chromium.
13. A metal sheet as claimed in claim 12 wherein the metal sheet is a steel sheet or a steel sheet plated with at least one metal chosen from tin, nickel and zinc.
21 - 1
14. A metal sheet as claimed in any one of claims 1 to 11 wherein the metal sheet has a mono layer of hydrated chromium oxide.
A c is. A metal sheet as claimed in claim 14, wherein the metal sheet is a steel sheet plated with tin or an aluminium alloy sheet.
16. A metal sheet as claimed in claim 1 substantially as herein described with reference to the Examples.
17. A food or beverage container manufactured from a metal sheet as claimed in any one of the preceding claims.
18. A method of manufacturing a metal sheet as claimed in any one of claims 1 to 16, said method comprising laminating said polyester resin film, either uncoated or pre-coated with a layer of thermosetting resin, onto said metal sheet, either uncoated or pre-coated with a layer of thermosetting resin, said metal sheet being heated to about the melting temperature of said polyester resin film.
22 -
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9400928A GB2285952B (en) | 1994-01-19 | 1994-01-19 | Metal sheet covered with polyester resin film for drawn and stretch formed can |
| FR9400708A FR2715344B1 (en) | 1994-01-19 | 1994-01-24 | Metal sheet covered with a polyester resin film, for boxes formed by stamping and drawing. |
| CA002114511A CA2114511C (en) | 1994-01-19 | 1994-01-28 | Metal sheet covered with polyester resin film for drawn and stretch formed can |
| NL9400154A NL194788C (en) | 1994-01-19 | 1994-02-01 | Metal plate coated with a polyester resin film for a deep-drawn look. |
| DE4403174A DE4403174C2 (en) | 1994-01-19 | 1994-02-02 | Metal sheet coated with a polyester resin film |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9400928A GB2285952B (en) | 1994-01-19 | 1994-01-19 | Metal sheet covered with polyester resin film for drawn and stretch formed can |
| FR9400708A FR2715344B1 (en) | 1994-01-19 | 1994-01-24 | Metal sheet covered with a polyester resin film, for boxes formed by stamping and drawing. |
| CA002114511A CA2114511C (en) | 1994-01-19 | 1994-01-28 | Metal sheet covered with polyester resin film for drawn and stretch formed can |
| NL9400154A NL194788C (en) | 1994-01-19 | 1994-02-01 | Metal plate coated with a polyester resin film for a deep-drawn look. |
| DE4403174A DE4403174C2 (en) | 1994-01-19 | 1994-02-02 | Metal sheet coated with a polyester resin film |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9400928D0 GB9400928D0 (en) | 1994-03-16 |
| GB2285952A true GB2285952A (en) | 1995-08-02 |
| GB2285952B GB2285952B (en) | 1997-06-25 |
Family
ID=27508537
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9400928A Expired - Lifetime GB2285952B (en) | 1994-01-19 | 1994-01-19 | Metal sheet covered with polyester resin film for drawn and stretch formed can |
Country Status (5)
| Country | Link |
|---|---|
| CA (1) | CA2114511C (en) |
| DE (1) | DE4403174C2 (en) |
| FR (1) | FR2715344B1 (en) |
| GB (1) | GB2285952B (en) |
| NL (1) | NL194788C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0798110A2 (en) * | 1996-03-29 | 1997-10-01 | Mitsubishi Polyester Film Corporation | Polyester film for laminating metal can end substrate surface |
| EP0838331A2 (en) * | 1996-10-23 | 1998-04-29 | Unitika Ltd. | White film to be laminated to metal surface and method of producing same |
| EP0826493A3 (en) * | 1996-08-29 | 2002-03-20 | Toyo Seikan Kaisha Limited | Laminate and container made of the same |
Family Cites Families (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS549632B2 (en) * | 1974-02-04 | 1979-04-26 | ||
| US4517255A (en) * | 1982-07-15 | 1985-05-14 | Toyo Kohan Co., Ltd. | Method for production of metal sheet covered with polyester resin film |
| DE3232755C2 (en) * | 1982-09-03 | 1984-06-28 | Inmont GmbH, 5300 Bonn | Zinc dust primer system for deformable phosphated or chromated sheet steel |
| US4614691A (en) * | 1984-10-01 | 1986-09-30 | Toyo Kohan Co., Ltd. | Method for production of metal sheet covered with polyester resin film |
| DE3436412A1 (en) * | 1984-10-04 | 1986-04-17 | Toyo Kohan Co., Ltd., Tokio/Tokyo | Process for the lamination of metal sheeting with polyester film |
| DE3588106T2 (en) * | 1984-11-09 | 1997-01-23 | Raychem Corp | Protect objects |
| JPS61149341A (en) * | 1984-12-25 | 1986-07-08 | Toyo Kohan Co Ltd | Manufacture of polyester resin film-covered metal plate |
| JPS6422530A (en) * | 1987-07-17 | 1989-01-25 | Toray Industries | Polyester film for pasting to metal |
| GB8724240D0 (en) * | 1987-10-15 | 1987-11-18 | Metal Box Plc | Laminated metal sheet |
| JPS63118336A (en) * | 1987-10-27 | 1988-05-23 | Matsushita Electric Works Ltd | Production of metallic foil-clad laminate |
| JPH01249331A (en) * | 1988-03-31 | 1989-10-04 | Toyo Kohan Co Ltd | Manufacture of metallic sheet coated with polyester resin superior in processability |
| US5094924A (en) * | 1988-10-19 | 1992-03-10 | Kenzo Matsui | Polyester resin film laminated steel sheet for drawn and ironed can |
| FR2638429B1 (en) * | 1988-10-19 | 1991-01-25 | Toyo Kohan Co Ltd | STEEL SHEET COATED WITH POLYESTER RESIN FILM AND PROCESS FOR PRODUCING THE SAME |
| JP2897129B2 (en) * | 1988-12-02 | 1999-05-31 | 工業技術院長 | Conductive paper, thermoplastic conductive paper and heat-fusible conductive paper |
| GB2234704B (en) * | 1989-07-28 | 1993-04-14 | Toyo Kohan Co Ltd | Method for producing steel sheet laminated with a polyester resin film |
| JPH0755552B2 (en) * | 1989-09-18 | 1995-06-14 | 東洋製罐株式会社 | Deep drawing can manufacturing method |
| CA2000356C (en) * | 1989-11-09 | 1995-08-22 | Atsuo Tanaka | Copolyester resin film laminated metal sheet and method for production thereof |
| GB2242159B (en) * | 1990-03-19 | 1994-02-02 | Toyo Kohan Co Ltd | Copolyester resin film-metal sheet laminates |
-
1994
- 1994-01-19 GB GB9400928A patent/GB2285952B/en not_active Expired - Lifetime
- 1994-01-24 FR FR9400708A patent/FR2715344B1/en not_active Expired - Lifetime
- 1994-01-28 CA CA002114511A patent/CA2114511C/en not_active Expired - Lifetime
- 1994-02-01 NL NL9400154A patent/NL194788C/en not_active IP Right Cessation
- 1994-02-02 DE DE4403174A patent/DE4403174C2/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0798110A2 (en) * | 1996-03-29 | 1997-10-01 | Mitsubishi Polyester Film Corporation | Polyester film for laminating metal can end substrate surface |
| US6045905A (en) * | 1996-03-29 | 2000-04-04 | Mitsubishi Polyester Film Corporation | Polyester film for laminating metal can end substrate surface |
| EP0798110A3 (en) * | 1996-03-29 | 2000-05-24 | Mitsubishi Polyester Film Corporation | Polyester film for laminating metal can end substrate surface |
| EP0826493A3 (en) * | 1996-08-29 | 2002-03-20 | Toyo Seikan Kaisha Limited | Laminate and container made of the same |
| EP0838331A2 (en) * | 1996-10-23 | 1998-04-29 | Unitika Ltd. | White film to be laminated to metal surface and method of producing same |
| EP0838331A3 (en) * | 1996-10-23 | 1998-12-16 | Unitika Ltd. | White film to be laminated to metal surface and method of producing same |
| US6150012A (en) * | 1996-10-23 | 2000-11-21 | Unitika Ltd. | White film to be laminated to metal surface and method of producing same |
Also Published As
| Publication number | Publication date |
|---|---|
| NL194788B (en) | 2002-11-01 |
| FR2715344B1 (en) | 1996-04-12 |
| DE4403174C2 (en) | 1999-02-11 |
| GB9400928D0 (en) | 1994-03-16 |
| DE4403174A1 (en) | 1995-08-03 |
| NL9400154A (en) | 1995-09-01 |
| NL194788C (en) | 2003-03-04 |
| GB2285952B (en) | 1997-06-25 |
| CA2114511C (en) | 2004-03-16 |
| CA2114511A1 (en) | 1995-07-29 |
| FR2715344A1 (en) | 1995-07-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PE20 | Patent expired after termination of 20 years |
Expiry date: 20140118 |