JPH0347153B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for preventing surface scratches on a metal plate laminated with a plastic film suitable as a container material. (Prior art) In general, surface-treated steel plates for containers such as electroplated tinplate and stain-free steel (TFS) and aluminum plates for containers are coated to prevent surface scratches that occur during transportation, can manufacturing, and handling. Saturated fatty acid esters with low volatility, low deterioration properties, and excellent lubricity such as dioctyl sebatate contain approximately 3 to 6
mg/ ^m2 electrostatically oiled. Furthermore, when these metal plates are subjected to can manufacturing processing after being painted, a lubricant is often added to the paint used to prevent surface flaws from occurring. In recent years, these container materials are often processed after being painted and printed, but most of the paints used are solvent-based thermosetting paints, and it takes a long time of 10 to 20 minutes to form a paint film. There are many problems, such as the need for heating for a long time, the scattering of a large amount of organic solvent when baking the paint, and the complicated cleaning of the roll coater used to apply the paint. From this point of view, a method of laminating plastic films such as polyethylene film, polypropylene film, polyethylene terephthalate film, etc. onto surface-treated steel plates or aluminum plates for containers is being considered as a new method to replace painting. However, the metal plates laminated with these plastic films are electroplated,
Similar to TFS and aluminum plates, surface scratches may occur during handling and can manufacturing. The metal plate laminated with the plastic film of the present invention is a new container material that can replace painted metal plates.
Prevention of surface scratches has not been thoroughly studied. (Problems to be Solved by the Invention) In the manufacturing process of metal plates laminated with plastic films, transportation, The object of the present invention is to provide a method for preventing surface scratches that occur during can manufacturing and handling. (Means for solving the problem) In order to continuously manufacture metal plates laminated with plastic film, (1) After applying adhesive to a surface-treated steel plate or aluminum plate for containers,
(2) A method of laminating a plastic film coated with an adhesive onto a surface-treated steel sheet or aluminum plate for containers and then heating it; (3) A method of heating a surface-treated steel sheet or aluminum sheet for containers that has been heated. There are two methods: (4) a method in which a plastic film coated with an adhesive is laminated on a heated surface-treated steel plate for containers and an aluminum plate, and then cooled. In any case, when a plastic film is laminated continuously and at high speed on these metal plates, it is necessary to cool the plastic film after laminating it. Generally, water is used for this cooling, but the present invention simultaneously cools the metal plate laminated with the plastic film.
By uniformly applying a small amount of fatty acid ester to the surface of a laminated plastic film, surface scratches can be prevented. In other words, a metal plate laminated with plastic film is placed in water or hot water.
The product is immersed in a solution in which more than one species of saturated fatty acid ester, phthalic acid ester, and citric acid ester are dispersed or emulsified, and then only moisture is removed by hot air drying. These esters can be applied uniformly at a faster rate by dipping a metal plate laminated with plastic film in the solution of the present invention, squeezing it with a squeezing roll to remove excess solution, and drying it. . Saturated fatty acid esters used include butyl stearate, butyl palmitate, dioctyl sebatate, dibutyl sebatate, and phthalate esters include dibutyl phthalate, dioctyl phthalate,
As the citric acid ester, acetyltributylcitric acid and acetyltriethylcitric acid are suitable. The amount of these esters to be dispersed or emulsified in water or hot water largely determines the amount of these esters to be applied to the surface of the laminated plastic film. The amount of esters is particularly important. The amount is 50~
A suitable amount is 1000 mg/, more preferably 100-500 mg/. When the amount of esters is less than 50mg/m2, the amount of esters applied to the surface of the laminated plastic film is about 1mg/ ^m2 ,
It has little effect on preventing surface scratches. In addition, from the standpoint of preventing surface scratches, 1000mg/
Although the above is effective, since these esters are non-volatile, they become sticky and become sticky when stacked with plastic laminated metal plates, making handling difficult. In particular, when a plastic film is laminated only on one side of a surface-treated steel plate for containers or an aluminum plate, the surface of these metals that are not laminated with a plastic film is often painted with an organic paint, which is used only to prevent surface scratches. However, it is also necessary to consider the effects on the paintability and paint adhesion of organic paints. Therefore, the upper limit of the amount of these esters to be dispersed or emulsified in water or hot water is preferably 700 mg/. If it exceeds 700 mg/ml, the paintability and paint adhesion of the surface of the metal plate not laminated with plastic film may deteriorate, which is undesirable. In order to disperse or emulsify these esters in water or hot water, they can be strongly stirred, or they can be mixed with water-soluble organic solvents such as alcohols such as ethyl alcohol and methyl alcohol, acetone, methyl ethyl ketone, etc. After dissolving it in ketones, it can be added to water or warm water and stirred vigorously. It is preferable to dissolve these esters in a water-soluble organic solvent and then add them to water or hot water in order to stabilize the emulsified state of these esters, but it is more preferable to use them in a stirred state.
As mentioned above, as methods for uniformly applying these esters to a metal plate laminated with a plastic film, there are methods other than dipping, which is carried out simultaneously with the cooling of the metal plate laminated with a plastic film, a spraying method, and a roll coating method. It is also possible to use the method of
Next, the temperature of the water or hot water used does not have a large effect on the amount of these esters applied to the surface of the metal plate laminated with plastic film, so there is no need to limit it in particular, but from the viewpoint of energy saving It is preferable to control the temperature below ℃. (Action of the invention) 50 to 1000 mg of one or more esters of saturated fatty acid ester, phthalate ester, and citric acid ester are added to a metal plate laminated with a plastic film as in the present invention in 1 liter of water or hot water. By dipping the plastic film into a dispersed or emulsified solution, applying it uniformly by spray coating, roll coating, or the like, and drying it, the occurrence of surface scratches on the laminated plastic film can be significantly prevented. (Example) Next, a method of implementing the present invention will be specifically described. Example 1 A commercially available TFS (manufactured by Toyo Kohan Co., Ltd., trade name Hitop, metal chromium content 100 mg/m ² , hydrated oxide chromium content 16 mg/m ² ) with a thickness of 0.22 mm was heated to 265°C to form a sheet with a thickness of 16 μm.
After laminating biaxially stretched polyethylene terephthalate film (manufactured by Toray, trade name: Lumirror),
Dioctyl sebatate (DOS) was immersed in a well-stirred solution of 100 mg of emulsified dispersion in water at a temperature of 40°C, rapidly cooled, and then placed on a laminated polyethylene terephthalate film.
DOS was applied, then squeezed with a roll and dried. Example 2 An aluminum plate with a thickness of 0.25 mm was immersed in Nippon Paint's Allozin #600 (trade name) and treated with chromic acid, heated to 255°C, and pre-treated with 10 mg/dm ² (dry weight) of epoxyphenol paint. of
The film was coated on a 25μm biaxially stretched polyethylene terephthalate film, dried at 100℃, laminated, and immersed in a solution containing 300mg of acetyltributyl citrate (ATBC) dissolved in ethyl alcohol in warm water at a temperature of 60℃. At the same time as cooling, ATBC was applied onto the laminated polyethylene terephthalate film, which was then squeezed with a roll and dried. Example 3 A commercially available TFS (manufactured by Toyo Kohan Co., Ltd., trade name Hitop, metal chromium content 105 mg/m ² , hydrated oxide chromium content 18 mg/m ² ) with a plate thickness of 0.25 mm was heated to 180°C to form a 50 μm thick plate.
After laminating low-density polyethylene (manufactured by Sumitomo Chemical, product name Sumikasen), it was further heated at 200℃ for 30 minutes.
A solution of 500 mg of dioctyl phthalate (DOP) dispersed in water at 25°C was sprayed onto the laminated film, squeezed with a roll, and dried. (Comparative example) DOS, ATBC and
Water without added DOP was used. The degree of scratches on the surface of the samples obtained in these Examples and Comparative Examples was measured using a Sutherland tester manufactured by Toyo Seiki Seisakusho.

[Table] Rub the surface of the laminated metal plate 10 times back and forth.
The degree of occurrence of flaws was evaluated on a five-point scale from 1 (no flaws) to 5 (severe flaws). These evaluation results are shown in Table 1. (Effects of the Invention) As explained in detail above, by applying one or more of saturated fatty acid ester, phthalate ester, and citric acid ester to a metal plate laminated with a plastic film by the method of the present invention, It was possible to prevent surface scratches that occur during transportation, can manufacturing, and handling of metal plates laminated with plastic films.

Claims (1)

[Claims] 1 One or more saturated fatty acid esters, phthalate esters, dispersed or emulsified in water,
A method for preventing surface scratches on a metal plate laminated with a plastic film, characterized by continuously applying a solution of citric acid ester to the metal plate laminated with a plastic film on one or both sides.