JP2009166354A - Resin-coated aluminum plate for molding process and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin-coated aluminum plate for a molding process, which can eliminate a failure such as fracture at a draw step of the molding process and peeling of a coating film by galling and to provide a method for manufacturing the resin-coated aluminum plate for the molding process. <P>SOLUTION: The method for manufacturing the resin-coated aluminum plate for the molding process comprises the steps of: alkali-cleaning an aluminum plate; water-washing the alkali-cleaned aluminum plate; acid-cleaning the water-washed aluminum plate; rinsing the acid-cleaned aluminum plate; water-washing the rinsed aluminum plate; drying the water-washed aluminum plate; applying a granular wax-containing coating material onto the dried aluminum plate; heating and drying the applied coating material at the temperature equal to or lower than the melting point of the added wax; again heating the half-dried coating material at the temperature equal to or higher than the melting point of the wax after cooled or successively; and cooling the heated coating material to room temperature. As a result, the coating film having 0.1-3.0 g/m<SP>2</SP>total coated amount (the total amount of a resin and the granular wax), 0.5-15% ratio of the granular wax amount to the total coated amount, 80-100% ratio of the particle size of the granular wax to the thickness of a resin layer being the coating film, 10-50% ratio of the layered wax amount on the surface of the coating film to the total coated amount and ≥25% ratio of the area to be occupied by the layered wax to the total surface area of the coating film can be formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin-coated metal plate having excellent molding processability, and particularly excellent in processability, galling resistance, and coating film adhesion in high-speed continuous press processing, can end materials, can body materials, The present invention relates to a resin-coated metal plate used in electrical and electronic equipment members, automobile body materials and building materials.

Aluminum plates and aluminum alloy plates (hereinafter collectively referred to as aluminum plates) have good corrosion resistance and are lightweight, so they are widely used in applications such as beverage can materials, building materials, electrical appliances and electronic parts, and automobile materials. Has been applied. When applying an aluminum plate to the said use, normally, an aluminum plate is press-molded to a predetermined shape, and is applied. There are two methods for press-forming aluminum plates: one is to supply sheet-fed sheets one by one to the press, and the other is to supply coil-shaped aluminum plates to the press continuously. Is widely adopted as an excellent manufacturing method in the field of use. In addition, the aluminum plate for the above uses is often used with a coating applied to the surface for the purpose of further improving the corrosion resistance, improving the appearance, preventing scratches, and the like.

  However, if the aluminum coated plate manufactured by the above-mentioned conventional technology is applied, the lubricity is insufficient, so that a so-called galling phenomenon occurs, such as a part subjected to strong processing, a seizure of the paint film on the mold and a peeling of the paint film. There is. Since this significantly reduces the commercial value of the press-formed product, its suppression is required.

  Further, as a covering material called outer wax, for example, as used in Patent Document 1, it is used as a molding material, but it satisfies the drawability at the time of molding but does not satisfy the caulking property.

Furthermore, as a coating material called inner wax, for example, it is used as a molding material as found in Patent Document 2, but the drawability at the time of high molding was not satisfied.
Japanese Patent Laid-Open No. 06-254490 JP-A-2005-343043

  The present invention has been made in view of such conventional problems, and an attempt is made to provide a resin-coated aluminum plate for molding that can eliminate the breakage of the drawing process during processing and the problem of film peeling due to galling. To do.

That is, as described in claim 1, the present invention is a resin-coated aluminum plate in which a coating film of a polymer resin is provided on the surface of an aluminum plate, and a particle diameter of 80 to 1000% of the resin layer thickness in the coating film. And the coating amount (the total amount of the resin and the wax) is 0.1 to 3.0 g / m ² . The amount of granular wax in the coating is 0.5 to 15% of the coating amount, the amount of the layered wax on the coating surface is 10 to 50% of the coating amount, and the area occupied by the layered wax on the coating surface is 25% or more. This is a resin-coated aluminum plate for molding processing.

Further, in claim 2, in claim 1, the polymer resin is a resin composed of one or more of polyester resin, epoxy resin, urethane resin and acrylic resin, and the wax is polyethylene wax. It prescribes.

Further, in claim 3, a paint containing granular wax is continuously applied on an aluminum plate that has been subjected to alkali washing, water washing, acid washing, rinsing, water washing and drying, and a film is formed at a temperature below the melting point of the added wax. The coating amount (total amount of resin and wax) is 0.1 to 0.1 by passing through a step of heating and drying, a step of reheating to a temperature equal to or higher than the melting point of the wax after cooling or continuously, and a step of subsequently cooling to room temperature. 3.0 g / m ² , the amount of granular wax in the coating is 0.5 to 15% of the coating amount, the particle size of the granular wax is 80 to 1000% of the resin layer thickness, and the amount of layered wax on the coating surface is the coating amount A method for producing a resin-coated aluminum sheet for molding processing, characterized in that a film having an area of 10 to 50% and the area occupied by the layered wax on the film surface is 25% or more, is defined.

  In the present invention, the coating amount (total amount of resin and wax) in the polymer resin coating film of the resin-coated aluminum plate for molding processing, the particle size of the granular wax, the amount of layered wax spreading on the surface, the area of the layered wax on the coating surface By specifying the rate, it is excellent in workability, galling resistance, and coating film adhesion in high-speed continuous press processing. For can end materials, can body materials, electrical and electronic equipment materials, automotive body materials and building materials, etc. Preferably used.

  A coating film made of a polymer resin and wax is provided on the surface of the aluminum plate.

  As the wax applicable to the present invention, since it is excellent in processability, it is essential to contain polyethylene wax. Besides that, plant-based plant carnauba, wood wax, rice wax, candelilla wax, animal-based lanolin, beeswax , Whale wax, ceramic wax, petroleum paraffin wax, microcrystalline wax, mineral-based montan wax, ozokerite, synthetic wax Fischer-Tropsch wax, oil-based synthetic wax, hydrogenated wax, processed / modified wax, compounded wax, modified wax Montan wax or the like may be included.

Moreover, as a form of the wax applicable to the present invention, the amount of the particulate wax in the coating may be 0.5 to 15% of the coating amount, and the area occupied by the layered wax on the coating surface may be 25% or more.
Here, the particulate wax in the coating contributes to galling resistance in press molding. The average particle size of the granular wax dispersed in the coating needs to be 80 to 1000% of the resin layer thickness. If it is less than 80% of the thickness of the resin layer, a film defect occurs and the caulking property deteriorates. If it is 1000% or more, it tends to fall off during molding, and the retention of wax is lowered.

  If the amount of the particulate wax dispersed in the coating is less than 0.5% of the coating amount, the caulking property during processing cannot be satisfied, and if it exceeds 15%, the retention of the wax in the coating also decreases. The galling property also decreases.

  In the present invention, the drawability is improved by forming a layered wax. By forming the coverage of the layered wax at 25% or more, the lubricity of the surface can be maintained. When the coverage is less than 25%, the area of the resin component having a high dynamic friction coefficient is increased, and the drawability is deteriorated.

  Further, the drawability is improved by setting the amount of the layered wax on the coating to 10 to 50% of the coating amount. When the amount of the layered wax is less than 10%, the lubricity at the time of molding becomes insufficient, and the drawability cannot be satisfied. Even if the amount of wax exceeds 50%, the effect is saturated and uneconomical.

Moreover, in this invention, the coating amount by resin, the wax disperse | distributed in the film, and the wax formed in layer form shall be 0.1-3.0 g / m < ² >. When the coating amount is less than 0.1 g / m ² , the coating is too thin, the mold and the aluminum material come into contact at the time of molding, and the drawability and caulking property cannot be sufficiently satisfied. On the other hand, when the coating amount exceeds 3.0 g / m ² , the effect is saturated, which is uneconomical.

  The organic resin used in the present invention is preferably one or a mixture of two or more of epoxy resin, alkyd resin, acrylic resin, urethane resin, phenol resin, melamine resin, polyvinyl butyral resin, and polyester resin. It should be noted that general additives such as reaction accelerators, stabilizers, and dispersants may be appropriately added to the base resin as long as they do not impair the spirit of the present invention. Among them, it is preferable to use a resin containing any of polyester, epoxy, urethane, and acrylic because both processability and coating film adhesion are excellent.

  Although it is the formation method of the film which concerns on the above-mentioned this invention, it should just be able to form a film and the method in particular is not prescribed | regulated. As a method for forming a film on a coating material, a roll coater method, a roll squeeze method, a chemi coater method, an air knife method, a dipping method, a spray method, an electrostatic coating method, etc. are used, and drying is performed by a general heating method or dielectric heating method. It can be carried out by the method, hot air blowing (air blow) method or the like. Of these methods, the roll coater method is preferred because of excellent uniformity of the coating film and good productivity. As the roll coater method, a gravure roll method with easy coating amount management, a natural coating method suitable for thick coating, a reverse coating method suitable for giving an aesthetic appearance to the coated surface, and the like can be employed.

  In order to form the coating film according to the present invention, it is preferable to perform the paint baking in two stages. In the first stage, baking is performed below the melting point of the wax, whereby the wax contained in the paint is dispersed in the coating. If the baking temperature is equal to or higher than the melting point, the wax melts before the resin hardens, so that no granular wax is formed in the coating film. The temperature may be set according to the melting point of the wax, but is preferably about 40 to 130 ° C. in consideration of productivity and the like.

  The drying time may be set according to the characteristics and film thickness of the resin. However, if the drying time is too long, the furnace becomes longer and the cost increases. Therefore, about 5 to 120 seconds are preferable.

  In the second stage drying, it is effective to perform baking at a temperature equal to or higher than the melting point of the wax. Below the melting point, layered wax is not formed on the surface. The baking temperature may be set in accordance with the melting point of the wax as in the first stage baking. However, if the temperature is too high, all of the granular wax in the coating is melted, which is not preferable. Although it depends on the heating time in baking, it is preferably 200 ° C. or lower.

  The drying time may be appropriately set in consideration of productivity, but if heated for a long time, all the granular wax in the coating film is melted. On the contrary, since the melted wax cannot be deposited in a layered manner on the surface of the coating film in a short time, 5 to 60 seconds is preferable.

  It is preferable to perform a cooling process after the two-stage baking process. The cooling method rapidly cools to room temperature or lower after drying. If the sheet is wound while leaving the drying furnace, the sheet wax is wound with the surface temperature being high and the surface wax is melted, so that the molten wax is fused with each other, resulting in problems such as blocking. This cooling process may be either air cooling or water cooling. However, in the case of water cooling, it is necessary to wind up after further removing moisture by air blow or the like. By adopting the structure as described above, it is possible to obtain a resin-coated aluminum plate for molding that has good workability and adhesion.

  Hereinafter, preferred embodiments of the present invention will be described in detail based on examples and comparative examples.

  A process of etching heat-treated JIS A 5182-O (0.8 mm thickness) with a medium etching type alkaline etching treatment solution → water washing step → pickling step → water washing step → aluminum plate treated in a drying step A material was used. The treatment liquid was sprayed on the plate surface by spraying, and drying was performed by blowing.

  Then, a predetermined coating is applied by a roll coater, and the first stage baking is performed at a predetermined reaching plate surface temperature (PMT) and time, and further, the first reaching stage temperature (PMT) and time is reached at the first stage. Baking was performed to prepare a resin-coated aluminum plate having a predetermined film configuration. Moreover, the coated board manufactured by each manufacturing method was produced for the comparison. Table 1 shows the production method of each sample and the coating composition obtained thereby.

Formability (drawability)
Deep drawing was performed with a mold having a punch diameter of 50 mmφ and a shoulder R5 mmR at a BHF of 600 N and a forming speed of 5 mm / s, and the limit drawing ratio (LDR) was determined.
○: Over LDR 2.1 Δ: LDR 1.9 to 2.1
X: Less than LDR 1.9

The dynamic friction coefficient (μ) at the 50th reciprocation was measured with a Bowden-type wear tester with a formability (sagging) test load = 500 gf, sliding speed = 0.6 mm / s, and steel ball diameter = 3/16 inch. did. In addition, about the thing which generate | occur | produced the galling in less than 50 round trips, it was set as x. O: μ ≦ 0.2
Δ: μ> 0.2
×: galling occurs in less than 50 round trip

After the 180 degree bending test of the coating film adhesion , the coating film peeling state was visually observed in the tape peeling test.
○: No peeling ×: With peeling

As shown in Table 1, all of the examples of the present invention are satisfactorily satisfied with no defects in drawability, caulking moldability, and coating film adhesion.
On the other hand, since the comparative examples deviated from the present invention, sufficient moldability (drawability and caulking properties) and coating film adhesion could not be obtained. In Comparative Example 12, the molding performance and the coating performance are inferior because the amount of the resin coating is outside the range of claims. Comparative Examples 13 and 14 are inferior in molding performance because the amount of granular wax is outside the claimed range. Comparative Examples 15 and 16 are inferior in molding performance and coating performance because the particle size ratio of the resin coating is outside the claimed range. Comparative Example 17 is inferior in molding performance because the amount of the layered wax is outside the claimed range. Comparative Example 18 is inferior in molding performance because the layered wax area ratio is outside the claimed range. Comparative Example 19 is inferior in molding performance because the baking process temperature is below the melting point. Since Comparative Example 20 does not have a wax-containing resin coating on the aluminum surface after pickling, the molding performance is inferior. Since Comparative Example 21 had only a wax after pickling treatment and no polymer resin film, the molding performance was inferior.

Claims (3)

A resin-coated aluminum plate provided with a coating film of a polymer resin on the surface of the aluminum plate, in which granular wax having a particle diameter of 80 to 1000% of the resin layer thickness is dispersed, and the surface A film in which the wax of the same component spreads in a layer form, the coating amount (total amount of resin and wax) is 0.1 to 3.0 g / m ² , and the amount of granular wax in the coating is 0.5 to 0.5 of the coating amount A resin-coated aluminum plate for molding processing, characterized in that the amount of layered wax on the surface of the coating is 15%, 10 to 50% of the amount of coating, and the area occupied by the layered wax on the surface of the coating is 25% or more. 2. The molding process according to claim 1, wherein the polymer resin is a resin composed of one or more of polyester resin, epoxy resin, urethane resin and acrylic resin, and the wax is polyethylene wax. Resin-coated aluminum plate. Continuously, alkali-washing, water-washing, acid-washing, rinsing, water-washing, applying a paint containing granular wax on a dried aluminum plate, and heating and drying the film at a temperature below the melting point of the added wax, after cooling Alternatively, the film amount (total amount of resin and wax) is 0.1 to 3.0 g / m ² by continuously heating again to a temperature equal to or higher than the melting point of the wax, and further continuing to cool to room temperature. The amount of granular wax in the coating is 0.5 to 15% of the coating amount, the particle size of the granular wax is 80 to 1000% of the resin layer thickness, the amount of layered wax on the coating surface is 10 to 50% of the coating amount, and layered A method for producing a resin-coated aluminum plate for molding, characterized in that a film having an area of 25% or more of the wax film surface is formed.