JPH09290480A - Laminated material for vessel cover and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the perfume retentivity and to provide excellent corrosion resistance by eliminating baking treatment necessary for a long baking furnace and an exhaust gas treating unit, reducing the manufacturing cost and providing excellent adhesive properties of a resin layer to an aluminum plate surface and external appearance characteristics. SOLUTION: An aluminum plate 1 is passed through a preheating furnace 2, preheated to a desired temperature, and then introduced to a pressure contact part 6a between a winding roll 5 and a press-bonding roll 6. At this time, the roll 6 is cooled to a desired temperature. Simultaneously, a fluidized polyester resin 4 molded by a T-die disposed above the part 6a between the roll 5 and the roll 6 flows down, and is press bonded to the aluminum plate between the rolls 6 and 5. The plate 1 is wound at a half circumference on the press- bonding roll together with the resin 4, and then altered in the advancing direction by an auxiliary roll 7b, and wound in a coiled state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated material for a lid of a container used for preservation of foods, etc., and in particular, a laminated material for a lid of a container which is suitable as a lid for a container of beer or the like where flavor and flavor are important. And a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a method of coating the surface of an aluminum plate with a resin layer has been used for the purpose of improving the corrosion resistance of a container lid or the like manufactured by molding the aluminum plate. Then, as a method for coating the surface of the aluminum plate with this resin layer, for example, a paint is produced by dissolving or dispersing a resin such as an epoxy resin, a vinyl chloride resin, and a polyester resin in an appropriate solvent, and the paint is coated with aluminum. After applying on the surface of the plate, by heating to remove the solvent and cure the resin coating,
Thus, there is a method of forming a resin layer on the surface of the aluminum plate.

In addition, there is also a method of coating the surface of a metal material by laminating a resin film on the surface thereof. For example, a method of coating the surface of a metal plate with a polyester resin has been disclosed (Japanese Patent Publication No. 61-61). -51987).
According to this, since the polyethylene terephthalate (PET) resin excellent in corrosion resistance, aroma retention, adhesiveness and workability is used, it is possible to obtain a polyester resin-coated metal plate excellent in processing corrosion resistance and processing adhesion. .

[0004]

However, when a resin layer-coated aluminum plate obtained by applying a coating material in which a resin is dissolved or dispersed in a solvent is used as a container for beverages, foods, etc., the applied resin layer The low molecular weight component of may be eluted in the contents of the container, if the amount of the elution is large, or if the flavor and flavor components in the contents are likely to be sorbed on the resin layer, the flavor of the food in the container and There is a problem that the flavor tends to be impaired.

When the surface of a metal plate is coated with a resin layer by applying a coating material, generally, in order to remove the solvent and cure the resin layer, a long baking of about 10 seconds or more is industrially required. It takes time, and for that purpose, for example, the length of the furnace needs to be about 50 m.
Further, in order to discharge the solvent volatilized by heating in the baking furnace without harm to the atmosphere, an exhaust treatment device is required.

On the other hand, in the method of coating the metal plate surface with a resin film by laminating a resin film,
Since the resin film used is extruded from a high molecular weight resin as a raw material, its molecular weight is extremely higher than that of the resin raw material used as a paint. Therefore, the amount of the resin component eluted from the resin film into the contents of the container is extremely small as compared with the case where the paint is used, so that the flavor and flavor of the food in the container is not deteriorated.

However, according to this method, since the resin is once formed into a film and then the film is attached to the metal plate, a separate manufacturing cost is required to form the film, resulting in an increase in the overall manufacturing cost. There is a problem. Therefore, in such a resin-coated metal plate, reduction in manufacturing cost is required.

The present invention has been made in view of the above problems, and does not require a baking process that requires a long baking furnace and an exhaust treatment device, can reduce the manufacturing cost, and can reduce the cost of the resin layer. It has excellent suitability as a container lid material such as adhesion to the aluminum plate surface and appearance characteristics, can improve aroma retention, and is preferably a laminated material for container lid having excellent corrosion resistance and the same. It is intended to provide a manufacturing method.

[0009]

A container lid laminate according to the present invention is formed by pressing a fluidized polyester resin molded by an extruder against a surface of a preheated aluminum plate by a cooled pressure bonding roll. It is characterized by having a polyester resin layer attached thereto. The thickness of this polyester resin layer is preferably 3 to 50 μm, and a phosphoric acid chromate treatment coating is formed on the surface of the aluminum plate.
It is desirable that one kind of coating film selected from the group consisting of a coating film composed of an organic resin and trivalent Cr, a chemical conversion treatment film containing Zr, and a chemical conversion treatment film containing Ti is formed.

In the method for producing a laminated material for a container lid according to the present invention, a fluidized polyester resin molded by an extruder is flowed between a preheated aluminum plate and a cooled pressure-bonding roll to perform the pressure-bonding. The fluidized polyester resin is pressed against the aluminum plate by a roll, and the polyester resin layer is applied to the surface of the aluminum plate.
Polyethylene terephthalate resin is preferably used as the polyester resin, and the polyester resin layer is preferably applied to the surface of the aluminum plate in a thickness of 3 to 50 μm.

When the melting point of the polyester resin used is T (° C.), it is preferable to preheat the aluminum plate at a preheating temperature of (T-150) to T (° C.). Further, on the surface of the aluminum plate, a phosphoric acid chromate-treated coating, a coating composed of an organic resin and trivalent Cr, Z
It is preferable to form one kind of film selected from the group consisting of a chemical conversion treatment film containing r and a chemical conversion treatment film containing Ti.

Further, the pressure roll comprises 10 to 2 of fluidized polyester resin laminated on the aluminum plate.
The temperature is preferably such that the cooling rate is 00 (° C./sec).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive experiments and researches conducted by the present inventors in order to solve the above-mentioned problems, a resin was obtained by extrusion coating a surface of an aluminum plate with a specific fluidizing resin formed by an extruder. The laminated plate on which the layer is applied has a low manufacturing cost, and the characteristics required as a container lid, that is, the adhesion of the resin layer to the aluminum plate,
It has been found that the corrosion resistance and appearance are excellent. Further, when this laminated plate is formed as a lid for a container for food or the like, the amount of the resin layer eluted into the contents is small and the effect of retaining the flavor and flavor of the contents is high.

FIG. 1 is a schematic diagram showing an extrusion laminating apparatus for explaining a method of manufacturing a laminated material for container lids according to an embodiment of the present invention.

The preheating furnace 2 has openings 2a and 2 at both ends thereof.
b is formed, and the aluminum plate 1
Is introduced and is led out from the opening 2b. An auxiliary roll 7a is arranged near the opening 2b, and a winding roll 5 and a pressure roll 6 are arranged downstream of the auxiliary roll 7a. Winding roll 5
The T die 3 is arranged above the pressure contact portion 6a between the pressure roller 6 and the pressure roll 6, and the fluidized polyester resin 4 is disposed from the T die 3 to the winding roll 5a.
It is designed to flow down to the pressure contact portion 6a between the pressure roller 6 and the pressure roller 6. Further, an auxiliary roll 7b is disposed downstream of the pressure roll 6.

Next, a method of manufacturing the laminated material will be described. After the aluminum plate 1 is passed through the preheating furnace 2 and preheated to a desired temperature, its traveling direction is changed by the auxiliary roll 7a, and the pressing portion 6 between the winding roll 5 and the pressure roll 6 is pressed.
a. At this time, the pressure roll 6 has been cooled to a desired temperature. At the same time, the T disposed above the press contact portion 6a between the winding roll 5 and the pressure roll 6
The fluidized polyester resin 4 is flowed down from the die, and is pressure-bonded to the aluminum plate between the pressure-bonding roll 6 and the winding roll 5. Then, the aluminum plate 1 is wound around the pressure-bonding roll together with the fluidized polyester resin 4 by, for example, a half turn, and then the advancing roll 7b changes the traveling direction thereof, and is wound into, for example, a coil shape. By doing so, the polyester resin layer is attached to one surface of the aluminum plate 1, so that the laminated material 8 of the aluminum plate 1 and the polyester resin layer can be manufactured.

In the laminated material 8 thus manufactured, the fluidized polyester resin 4 flows down on the surface of the aluminum plate 1 after it has been preheated, so that the fluidity of the resin 4 is increased and the resin 4 and the aluminum are The adhesion with the plate 1 is improved. When not preheating the aluminum plate 1,
Alternatively, when the preheating temperature is low, the adhesion of the resin layer to the aluminum plate cannot be sufficiently obtained, so that the corrosion resistance is lowered.

When the melting point of the solid polyester resin applied to the aluminum plate is T (° C), and the preheating temperature of the aluminum plate is less than (T-150) ° C, the adhesion of the resin layer to the aluminum plate is low. Is reduced. On the other hand, when the preheating temperature of the aluminum plate exceeds T ° C., the fluidity of the resin is further improved, but this resin is decomposed, which is not preferable. Therefore, the preheating temperature of the aluminum plate is (T-1
50) to T (° C.) is preferable. For example, as a polyester resin, polyethylene terephthalate (P
When the ET) resin is used, the melting point T of this solid PET resin is 255 ° C., so it is desirable to set the preheating temperature of the aluminum plate to 105 to 255 ° C.

Further, if the cooling rate at which the fluidized polyester is cooled by the pressure roll is less than 10 (° C./sec), crystallization of the laminated polyester resin proceeds and the workability of the polyester resin is deteriorated. Corrosion resistance decreases. On the other hand, when the cooling rate exceeds 200 (° C./sec), the fluidized polyester resin does not come into sufficient contact with the irregularities on the surface of the aluminum plate, resulting in poor adhesion. Therefore,
The cooling temperature of the pressure roll is 10 to 200 (° C / sec) for the fluidized polyester resin laminated on the aluminum plate.
It is preferable that the temperature is such that the cooling rate is within the range.

As the aluminum plate used in the present invention, any aluminum plate can be used without restricting its composition and the like as long as it fulfills the function as a lid of a container. For example, Al-Mg based alloys such as alloy numbers 5052, 5082 and 5182 defined in JIS H 4000 and wrought materials of Al-Mg based alloys such as 3003 and 3004 are suitable. Further, the form thereof may be any form as long as the polyester resin layer can be adhered to at least the inner surface of the lid of the aluminum plate, and it is preferably coiled.

The inner surface of the lid is one side or both sides of the aluminum plate or a part thereof, and when the manufactured laminated material is molded as a lid of the container, the inner surface of the container is covered with polyester resin. It suffices if the layers can be applied.

Further, the thickness of the aluminum plate is not particularly limited, and can be appropriately determined as long as the container lid having a desired shape can be molded and the thickness can be used for a long time.

In the present invention, the surface of the aluminum plate is preferably surface-treated for the purpose of improving the corrosion resistance of the aluminum plate and improving the adhesion to the resin layer to be adhered. This surface treatment is, specifically,
Forming a phosphoric acid chromate treatment coating, a coating composed of an organic resin and trivalent Cr, or a chemical conversion treatment coating containing Zr or Ti. When these surface treatments are applied to the aluminum surface, the surface of the aluminum plate is Is chemically produced as a film containing oxides of metal components in the film and bound water. Since this bound water has a strong affinity with the polar group of the resin layer, the adhesion of the resin layer to the surface of the aluminum plate can be improved. Further, the oxide of the metal component acts as a barrier layer for oxygen, moisture and various ions that permeate the resin layer, and has an effect of protecting the surface of the aluminum plate.

The phosphoric acid chromate-treated coating is formed by immersing the aluminum plate in a mixed aqueous solution of chromic acid, phosphoric acid and hydrofluoric acid, or by spraying or applying the mixed aqueous solution of these on the surface of the aluminum plate. You can These coatings are preferably formed in a coating amount capable of obtaining desired corrosion resistance and desired adhesion with the resin layer to be laminated.

Further, since the polyester resin layer used in the present invention is adhered to an aluminum plate, it will be in contact with the contents for a long time if it is molded so as to be the inner surface of the lid of the container. Therefore, when the contents of this container are beverages or foods, it is necessary to ensure food safety. Therefore, while maintaining the quality of the beverage or food, in order to maintain the flavor and flavor, the adhesiveness between the resin layer applied to the aluminum plate and the aluminum plate is excellent and the resin component in the contents. Must not elute or the elution amount must be extremely small.

Therefore, in the present invention, the resin layer deposited on the aluminum plate is flowed down to the surface of the aluminum plate in a fluidized state, and when it is cooled and solidified on the surface, it has high adhesion to the aluminum plate. Need to get. Polyester resin ensures food hygiene safety,
It is a resin that can improve the adhesion to an aluminum plate. In addition, since the resin is extruded and formed using a resin having a high molecular weight as a raw material, the molecular weight is increased, and the resin can be prevented from being eluted into the contents of the container. Among them, polyethylene terephthalate resins are particularly preferable because they are easily produced because they are mass-produced and have excellent fragrance retention properties for maintaining the flavor and flavor of foods and the like.

Also, the thickness of the polyester resin layer is not particularly limited, but the thickness of the resin layer is 3
If it is less than μm, the workability of extrusion from the die is significantly reduced, and sufficient corrosion resistance when processed as a laminated material may not be obtained. On the other hand, even if the thickness of the resin layer is processed to exceed 50 μm, the effect of improving the corrosion resistance and the like of the aluminum plate cannot be further improved, and the raw material cost increases, which is not preferable. . Therefore, the thickness of the polyester resin layer applied to the aluminum plate is preferably 3 to 50 μm.

[0028]

EXAMPLES Examples of a laminated material for a container lid and a method for producing the same according to the present invention will be specifically described below in comparison with comparative examples thereof.

First, an aluminum plate of JIS A5052P having a thickness of 0.30 mm, for example, was prepared without surface treatment and with various surface treatments to form a coating film. Next, this aluminum plate was preheated at various preheating temperatures in the preheating furnace 2 using the extrusion laminating apparatus shown in FIG. 1, and then introduced into the pressure contact portion 6 a between the winding roll 5 and the pressure bonding roll 6. At the same time, the fluidized polyester resin molded by the T-die 3 was extruded and flowed down to the pressure contact portion 6a to manufacture laminated materials of resin layers of various thicknesses and aluminum plates. However, the diameters of the winding roll 5 and the pressure roll 6 were both 300 mm.

Next, the laminated plate thus obtained was subjected to a drawing process to form a drawing cup so that the surface on which the resin layer was adhered was the inner surface, and these samples were used as examples.
However, as the forming conditions for drawing, the blank diameter is 60 mm, the punch diameter is 40 mm, and the drawing ratio is 1.
It was set to 5.

Further, in Comparative Example No. No. 14 is a laminated material manufactured by flowing down a fluidized polyethylene terephthalate resin molded by an extruder onto the surface of an aluminum plate which is not preheated. At this time, the thickness of the resin layer was 10 μm. Further, in Comparative Example No. Fifteen
Is a paint manufactured by dissolving a polyester resin in methyl ethyl ketone, and after applying the paint to the surface of an aluminum plate, the solvent is removed by heating and the resin film is cured to produce a laminated plate. Is. The method of processing the drawn cup from these laminated plates is the same as in the embodiment.

Next, after the appearance of the samples of Examples and Comparative Examples was evaluated, the adhesion and corrosion resistance of the resin layer were evaluated, and the amount of potassium permanganate consumed was measured to maintain the squeezing cup. The scent was evaluated. The test method of each test is shown below.

As a method of evaluating the adhesiveness of the resin layer, first, the sample was immersed in boiling distilled water in a beaker and held for 30 minutes, then taken out, and water drops were wiped off with a paper towel. Thereafter, a cross cut was made with a cutter knife on the surface on which the resin layer was adhered, the adhesive tape was applied to the cross-cut portion, and this was peeled off to observe the releasability of the resin layer.

Further, the corrosion resistance was evaluated by observing the inner surface of the squeezing cup after 1% saline was put in the sample and kept at a temperature of 95 ° C. for 1 week.

Further, the aroma retaining property as the container lid of the squeezing cup is determined by immersing the sample in distilled water at 60 ° C. for 30 minutes to elute the resin component in the distilled water and then titrating with potassium permanganate. It was evaluated by measuring the consumption of potassium manganate. That is, the larger the consumption of potassium permanganate, the larger the amount of the resin component eluted in distilled water, indicating a lower fragrance retention.

The manufacturing conditions of these laminated plates are shown in Table 1 below, and the evaluation results are shown in Table 2 below.

[0037]

[Table 1]

[0038]

[Table 2]

As shown in Table 1 above, a fluidized polyethylene terephthalate resin was allowed to flow down onto the surface of a preheated aluminum plate, and the resin layer was adhered by pressing the fluidized polyethylene terephthalate resin with a pressure bonding roll. In Nos. 1 to 13, the consumption amount of potassium permanganate was 5 ppm or less, and exhibited excellent fragrance retaining properties. In particular, Example No. 1 to 10, 12
Since No. 13 and No. 13 have been subjected to a surface treatment on the surface of the aluminum plate, the adhesion of the resin layer to the surface of the aluminum plate was excellent. Among these, in particular, Example No. 2 to 1
Since Nos. 0, 12 and 13 were coated with the resin layer with a thickness of 3 μm or more, the corrosion resistance was also excellent.

In addition, in Example No. Nos. 3 and 6 to 13 are formed with resin layers having the same thickness. Since 3 and 8 to 13 use the polyethylene terephthalate resin as the polyester resin layer, the fragrance retaining property was further improved.

On the other hand, Comparative Example No. 1 in which the aluminum plate was not preheated. Regarding No. 14, peeling and corrosion occurred.
Further, Comparative Example No. 1 in which a resin layer was formed by applying a coating material in which a resin was dissolved to the surface of an aluminum plate. Fifteen
Inferior in aroma retention compared to the examples.

[0042]

As described in detail above, according to the present invention,
Since the laminated material is manufactured without using a resin paint dissolved in a solvent, there is no need for a baking process that requires a long baking furnace and an exhaust treatment device, and since there is no step of molding a resin film, manufacturing The cost can be reduced. Also, after preheating the aluminum plate, the fluidized polyester resin formed by an extruder is flowed down to laminate, so that the resin layer has excellent suitability as a container lid material such as adhesion to the aluminum plate surface and appearance characteristics. In addition, it is possible to obtain a laminated material for a container lid, which is capable of preserving the flavor, flavor and the like of the food etc. in the container in an excellent state. Furthermore, when a desired coating is formed on the surface of the aluminum plate before laminating the resin layers, the adhesion of the resin layer to the aluminum plate and the corrosion resistance of the laminated plate are further improved. Furthermore, if the type of polyester resin to be used, the thickness of the resin layer and the preheating temperature are appropriately selected, the aroma retaining property, the adhesiveness and the corrosion resistance can be further improved.

[Brief description of drawings]

FIG. 1 is a schematic view showing an extrusion laminating apparatus for explaining a method for manufacturing a laminated material for container lids according to an example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1; Aluminum plate 2; Preheating furnace 3; T die 4; Fluidized polyester resin 5; Winding roll 6; Pressure roll 6a; Pressure contact part 7a, 7b; Auxiliary roll

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B32B 31/20 9349-4F B32B 31/20 B65D 81/24 B65D 81/24 G C23C 22/33 C23C 22/33 // B29L 9:00

Claims (9)

[Claims] 1. A container lid laminate having a polyester resin layer deposited on a surface of a preheated aluminum plate by pressing a fluidized polyester resin molded by an extruder with a cooled pressure-bonding roll. Material. 2. The container lid laminate according to claim 1, wherein the polyester resin layer has a thickness of 3 to 50 μm. 3. The surface of the aluminum plate is selected from the group consisting of a phosphoric acid chromate treatment coating, a coating composed of an organic resin and trivalent Cr, a chemical conversion treatment coating containing Zr and a chemical conversion treatment coating containing Ti. The laminated material for a container lid according to claim 1 or 2, characterized in that the formed one kind of coating is formed. 4. A fluidized polyester resin molded by an extruder is flown between a preheated aluminum plate and a cooled pressure-bonding roll, and the fluidizing polyester resin is pressed against the aluminum plate by the pressure-bonding roll. A method for producing a laminated material for container lid, which comprises depositing a polyester resin layer on the surface of an aluminum plate. 5. The method for producing a laminated material for a container lid according to claim 4, wherein a polyethylene terephthalate resin is used as the polyester resin. 6. The polyester resin layer has a thickness of 3 to 50 μm.
The method for producing a laminated material for a container lid according to claim 4 or 5, wherein the aluminum plate surface is adhered to a thickness of m. 7. The melting point of the polyester resin is T (° C.)
Then, the aluminum plate is (T-150) to T
5. Preheating at a preheating temperature of (° C.).
7. The method for producing a laminated material for container lid according to any one of items 1 to 6. 8. The surface of the aluminum plate is selected from the group consisting of a phosphoric acid chromate-treated coating, a coating composed of an organic resin and trivalent Cr, a Zr-containing chemical conversion coating, and a Ti-containing chemical conversion coating. The method for producing a laminated material for container lid according to any one of claims 4 to 7, characterized in that one kind of coating is formed. 9. The fluidizing polyester resin laminated on the aluminum plate in the pressure roll is 10 to 200.
The method for producing a laminated material for container lid according to claim 4, wherein the temperature is set to a cooling rate of (° C./second).