Method and apparatus for producing film-coated metal plate

Abstract

Provided is a method for producing a film-coated metal plate, comprising the steps of: (1) pre-heating and soaking a metal plate; (2) laminating a film on the metal plate, with a deflector roller configured to be movable in a horizontal direction to adjust an angle α between the metal plate and a vertical direction; (3) cooling the metal plate; (4) compressing the metal plate to dry it; (5) reheating and post-processing the metal plate. A device for producing a film-coated metal plate is also provided, which comprises: an induction heating apparatus, a deflector roller (4) configured to be movable in a horizontal direction to adjust an angle α between the metal plate and a vertical direction, a thin film guide roller (6), a film-coating roller (7), a cooling apparatus (9), a compressing and drying roller (12), a reheating apparatus (14) and an air cooling apparatus (15).

Claims

1. A production method for a film-laminated metal plate, comprising: (1) preheating and soaking a metal plate; (2) laminating a film on the metal plate using film-laminating rolls, comprising controlling an angle β to be in a range of 30-70°, wherein said angle β is an angle between the film and a vertical direction, and the film enters a roll gap between film-laminating rolls at said angle β; controlling an angle α to be in a range of >0 to 20° with a deflector roll configured to be movable in a horizontal direction to adjust the angle α between the metal plate and a vertical direction, wherein the metal plate enters the roll gap at said angle α; and then laminating the film on the metal plate using the film-laminating rolls, while controlling a temperature of the film-laminating rolls to be in a range of 50-130° C.; (3) cooling a surface of a resulting film-laminated metal plate rapidly to a temperature equal to or less than 50° C. at first by water spray cooling, followed by water quenching in a water quenching tank; (4) squeezing the film-laminated metal plate to remove most water from the surface of the film-laminated metal plate; and (5) heating the film-laminated metal plate to a temperature in the range of 50-130° C., holding for 5-40 s, and then air cooling the film-laminated metal plate to room temperature quickly.

2. The production method according to claim 1, wherein there is a time interval of 0.5-5 s after step (2) and before step (3).

3. The production method according to claim 1, wherein in step (1), the preheating increases a temperature of the metal plate to 60-80% of a target temperature of the metal plate, and the soaking increases the temperature of the metal plate to the target temperature.

4. The production method according to claim 1, wherein the water spray cooling in step (3) is carried out at a cooling rate ≥150° C./s.

5. The production method according to claim 1, wherein the air cooling in step (5) is carried out at a cooling rate ≥80° C./s.

6. The production method according to claim 1, wherein α:β is 1:3-1:8 when the angle α is greater than 5 degrees in step (2).

Description

DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a flow chart showing schematically a method for producing a film-laminated metal plate according to the disclosure.

(2) FIG. 2 is a schematic view showing a structure of an apparatus for producing a film-laminated metal plate according to an embodiment of the disclosure.

(3) FIG. 3 is a schematic view showing a structure of a cooling device in an apparatus for producing a film-laminated metal plate according to an embodiment of the disclosure.

DETAILED DESCRIPTION

(4) The method and apparatus for producing a film-laminated metal plate according to the disclosure will be further explained and illustrated with reference to the accompanying drawings of the specification and the specific examples. Nonetheless, the explanation and illustration are not intended to unduly limit the technical solution of the disclosure.

(5) FIG. 1 shows schematically a flow chart of a method for producing a film-laminated metal plate according to the disclosure.

(6) As shown by FIG. 1, the flow of a method for producing a film-laminated metal plate according to the disclosure comprises the following steps:

(7) (1) A metal plate is preheated and soaked, wherein the preheating substep increases a temperature of the metal plate to 60-80% of a target temperature of the metal plate, and the soaking substep increases the temperature of the metal plate to the target temperature.

(8) (2) Hot film lamination: an angle β is controlled at 30-70° at which angle α thin film enters a roll gap between film-laminating rolls, wherein said angle β is an angle between the thin film and a vertical direction; an angle α between the metal plate and the vertical direction is controlled at 0-20°; and then the film is heat-laminated on the metal plate using the film-laminating rolls. In some embodiments, when the angle α is greater than 5 degrees, α:β is 1:3-1:8. In some other embodiments, the temperature of the film-laminating rolls is controlled at 50-130° C.

(9) (3) After the film lamination, an interval time of 0.5-5 s passes and then the metal plate begins to be cooled: the surface temperature of the film-laminated metal plate is decreased rapidly to 50° C. or less by spraying water, and then the film-laminated metal plate is water quenched in a water quenching tank. In some embodiments, the cooling rate of the water spray cooling is ≥150° C./s.

(10) (4) The film-laminated metal plate is squeezed to remove most water from the surface of the film-laminated metal plate.

(11) (5) Reheating and post-treatment: the film-laminated metal plate is heated to a temperature in the range of 50-130° C., held for 5-40 s, and then air cooled to room temperature quickly. In some embodiments, the cooling rate of the air cooling is ≥80° C./s.

(12) The above metal plate may be a tin plate or chrome plate, and it can also be an aluminum plate, etc.

Examples 1-9 and Comparative Examples 1-3

(13) The film-laminated metal plates of the abovementioned Examples and Comparative Examples were obtained using the above steps. A thickness of 25 μm was chosen for the film. A chrome plate having a thickness of 0.2 mm was chosen for the metal plates.

(14) Table 1 lists the specific process parameters of the manufacturing method in the Examples and Comparative Examples.

(15) TABLE-US-00001 TABLE 1 Step (1) Proportion based on Step (2) Step (3) Step (5) target Film-laminating Temperature Cooling Temperature Cooling temperature roll temperature to cool to Interval rate to heat to Soaking rate (%) β (°) α (°) α:β (° C.) (° C.) time (s) (° C./s) (° C.) time (s) (° C./s) Ex. 1 70% 60 15 1:4 125 45 1 180 55 10 90 Ex. 2 80% 60 15 1:4 125 32 3 220 100 20 100 Ex. 3 70% 60 15 1:4 125 49 5 150 60 5 80 Ex. 4 60% 50 10 1:5 96 38 1 190 80 20 110 Ex. 5 70% 50 10 1:5 96 40 3 180 120 10 90 Ex. 6 80% 50 10 1:5 96 41 5 160 100 30 120 Ex. 7 80% 40 5 1:8 73 36 1 200 85 10 80 Ex. 8 70% 40 5 1:8 73 44 3 160 110 5 80 Ex. 9 70% 40 5 1:8 73 33 5 220 60 40 120 Comp. 70% 40 0 0 60 39 5 180 80 30 120 Ex. 1 Comp. 70% 40 0 0 60 50 7 150 120 20 110 Ex. 2 Comp. 80% 40 0 0 60 43 10 190 60 10 90 Ex. 3

(16) The film-laminated metal plates of the above Examples and Comparative Examples were sampled to measure the melt layer thicknesses of the films on two sides (side A and side B) of the film-laminated metal plates, and measure the adhesion property and corrosion resistance of the films on side B of the film-laminated metal plates. The relevant data are listed in Table 2.

(17) TABLE-US-00002 TABLE 2 Melt layer Melt layer thickness of the thickness of the Adhesion film on side A film on side B property of Acid No. (μm) (μm) the film resistance Ex. 1 13 5 ⊚ ◯ Ex. 2 13 5 ⊚ ◯ Ex. 3 13 5 ⊚ ◯ Ex. 4 9.5 5 ⊚ ⊚ Ex. 5 9.5 5 ⊚ ◯ Ex. 6 9.5 5 ⊚ ◯ Ex. 7 7 5 ⊚ ⊚ Ex. 8 7 5 ⊚ ⊚ Ex. 9 7 5 ⊚ ◯ Comp. Ex. 1 5 5 ◯ ◯ Comp. Ex. 2 5 5 ◯ ◯ Comp. Ex. 3 5 5 ◯ Δ Note: X—poor; Δ—acceptable; ◯—good; ⊚—very good.

(18) The abovementioned adhesion property and acid resistance of the films were measured according to the following methods:

(19) Method for testing the adhesion property of the films: a crosshatch tape pull test was used to evaluate the adhesion property of the films in the film-laminated metal plates. A film-laminated metal plate sample was cut into 150 mm*150 mm in size. A scriber was used to scribe 10 parallel lines horizontally and vertically respectively in the central part of a sample. The two sets of parallel lines intersected each other, and each two adjacent parallel lines were spaced by a distance of 1 mm. As such, 150 small squares of the same size were formed from these two sets of parallel lines. Then, a specialized adhesive tape was intimately adhered to the scribed zone. The tape was peeled off by gripping an end of the tape and pulling rapidly in an inclined upward direction. The degree to which the film was released was observed to evaluate the adhesive power of the film.

(20) Method for testing acid resistance: evaluation of acid resistance was utilized to represent evaluation of corrosion resistance. A film-laminated metal plate sample was immersed in a 1.5% citric acid solution, and boiled at 121° C. for 30 min. After cooling, the sample was taken out, and spots corroded by the acid on the surface of the sample were observed to evaluate the corrosion resistance of the film-laminated metal plate.

(21) As shown by Table 2, the melt layer thickness of the film on side A was larger than the melt layer thickness of the film on side B for each of the film-laminated metal plates of Examples 1-9; and the melt layer thickness of the film on side A was equivalent to the melt layer thickness of the film on side B for each of the film-laminated metal plates of Comparative Examples 1-3. With reference to Table 1, this suggests that the melt layer thickness of the film on side A is influenced by angle α. The adhesion power of the films in Examples 1-9 reached “very good”, and the corrosion resistance property of Examples 4, and 7-8 reached “very good”. The corrosion resistance property of Comparative Example 3 was “acceptable”.

(22) FIG. 2 shows schematically a structure of an apparatus for producing a film-laminated metal plate according to an embodiment of the disclosure.

(23) As shown by FIG. 2, the apparatus for producing a film-laminated metal plate according to the embodiment comprises:

(24) an induction heating device arranged in a direction along which a metal plate 1 is conveyed, and configured to preheat and soak the metal plate 1, wherein the induction heating device comprises an induction heater 2 and three induction heating rolls 3 arranged sequentially in the direction along which the metal plate 1 is conveyed; a deflector roll 4 configured to be movable in a horizontal direction to adjust an angle α between the metal plate 1 and a vertical direction; two film guide rolls 6 arranged at side A and side B of the metal plate 1 respectively, and configured to guide a film 5 into a roll gap between film-laminating rolls 7 to be described hereafter, and adjust an angle β at which the film 5 enters the roll gap between the film-laminating rolls; two film-laminating rolls configured to hot laminate the film 5 on the metal plate 1; two cooling rolls 8 arranged in correspondence to the two film-laminating rolls 7, wherein the cooling rolls 8 contact the film-laminating rolls 7 to control the temperature of the film-laminating rolls 7; a cooling device configured to cool the film-laminated metal plate 16, wherein the cooling device comprises water spray beams 9 and a water quenching tank 10, wherein an immersed roll 11 is arranged in the water quenching tank 10; two squeezing rolls 12 configured to squeeze the film-laminated metal plate to dry; a turning roll 13 configured to direct the film-laminated metal plate 16 to a reheating device 14 to be described hereafter; the reheating device 14 configured to reheat the film-laminated metal plate 16, wherein the reheating device 14 comprises a hot air oven; an air cooling device 15 configured to air cool the reheated film-laminated metal plate 16, wherein the air cooling device 15 comprises air knives. Particularly, four pairs of air knives for cooling are intimately arranged side by side in the direction for conveying the metal plate.

(25) In the above technical solution, after the metal plate 1 leaves the induction heating rolls 3 and before it enters the film-laminating rolls 7, the temperature of the metal plate 1 will decrease to some extent. In particular, temperature drops more quickly at two side portions of the metal plate 1. As a result, the temperature does not distribute uniformly across the width of the metal plate 1. Therefore, the deflector roll 4 is designed to be able to subject the side portions to reinforced heating to make up the temperature difference between the side portions and the central portion of the metal plate 1, so as to guarantee temperature uniformity across the width of the metal strip before the metal plate 1 enters the film-laminating rolls 7.

(26) FIG. 3 shows schematically a structure of a cooling device in an apparatus for producing a film-laminated metal plate according to an embodiment of the disclosure.

(27) As shown by FIG. 3, the cooling device 9 comprises: water spray beams 91, wherein two parallel water spray beams 91 are arranged in a corresponding manner at each side of the film-laminated metal plate 16, nozzles 92 are arranged on each water spray beam 91, and the nozzles 92 on the two water spray beams 91 are arranged in a staggering manner; a water quenching tank 10, wherein the film-laminated metal plate 16 is water quenched in the water quenching tank 10. 8-30 nozzles 92 are designed on each of the water spray beams 91 (the number indicated in the figure is only illustrative). The nozzles 92 are fan-type nozzles, and water sprayed therefrom has a sector-like distribution. The angle between the sector and the horizontal plane is between 10-20 degrees. In addition, the water spray beams 91 are coupled to a driving mechanism which drives the water spray beams 91 to move in the direction alone which the film-laminated metal plate 16 is conveyed, such that the water spray beams can be positioned by the driving mechanism in the direction for conveying the metal plate, in light of the desired range of the cooling time (e.g. 0.5-5 s) and the conveying speed of the metal plate, so as to ensure that the surface temperature of the film-laminated metal plate is cooled rapidly to a temperature equal to or less than the glass transition temperature of the film (e.g. a polyester film) in a period of cooling time within the desired range.

(28) Operation of the above apparatus for producing a film-laminated metal plate comprises the following steps:

(29) (1) The metal plate 1 is first preheated by the induction heater 2 to 60-80% of the target temperature of the metal plate, and then soaked by the induction heating rolls 3 to the target temperature.

(30) (2) The metal plate 1 is conveyed downward vertically, deflected by the deflector roll 4 toward side A to an angle α, and enters the film-laminating rolls 7. Meanwhile, due to the action of the film guide rolls 6, the films 5 form an angle β with the metal plate 1 at both side A and side B, and enter the film-laminating rolls 7, so that hot lamination of the films is finished, and the film-laminated metal plate 16 is formed primarily. At the same time, the cooling rolls 8 contact the film-laminating rolls 7 to control the temperature of the film-laminating rolls 7.

(31) (3) The film-laminated metal plate 16 is further conveyed downward vertically, firstly cooled by water sprayed from the water spray beams 9 to rapidly decrease the surface temperature of the film-laminated metal plate 16 to a temperature equal to or less than the glass transition temperature of the films, and then water quenched by means of the immersed roll 11 in the water quenching tank 10.

(32) (4) The film-laminated metal plate 16 is squeezed by the squeezing rolls 12 to dry.

(33) (5) The film-laminated metal plate 16 is guided by the turning roll 13 into the reheating device 14 to heat the film-laminated metal plate 16 to a temperature equal to or higher than the glass transition temperature of the films, held, and then air cooled rapidly to room temperature.

(34) It is to be noted that there are listed above only specific examples of the invention. Obviously, the invention is not limited to the above examples. Instead, there exist many similar variations. All variations derived or envisioned directly from the disclosure of the invention by those skilled in the art should be all included in the protection scope of the invention.