TW201437008A - Pre-coated aluminum plate and manufacturing method thereof - Google Patents

Abstract

The present invention provides a pre-coated aluminum plate with excellent scratch resistance and formability, which can be used as the exterior plate and structural member in household appliances and automotive mounting parts and the like. The pre-coated aluminum plate according to the present invention is coated on the surface with a hard film of 0.2 to 10<mu>m in thickness, which is characterized that the hard film is composed of a resin containing C of more than 30 atomic% and less than 50 atomic%, and N, Si, O respectively of more than 10 atomic% and less than 30 atomic%, in this resin, the content (atomic%) of Si is more than 0.8 times and less than 1.2 times that of O. Such pre-coated aluminum plate is formed by applying a coating material containing C, N, Si, O to an aluminum plate, baking at 210 to 280<DEG>C, thereby forming the hard film. The present invention also discloses a manufacturing method comprising the followings: a coating step of applying a coating material containing C, N, Si, O on one or both sides of an aluminum plate; a baking step of subjecting the aforementioned coating material to a baking treatment at a temperature higher than 210<DEG>C or lower than 280<DEG>C.

Description

Precoated aluminum plate and manufacturing method thereof

The present invention relates to an aluminum plate and an aluminum alloy plate which are applied to an outer sheet material and a structural member of a household appliance product, a vehicle mounting component, and the like, and a coating having an excellent scratch resistance and moldability on the surface of the aluminum plate by coating. Aluminium plate is coated.

In an aluminum plate and an aluminum alloy plate which are applied to a sheet material and a structural member other than a household appliance product and a vehicle mounting component, in order to impart corrosion resistance to the surface, a better appearance, and scratch resistance to maintain the appearance, and further For the other characteristics corresponding to the use, a pre-coated plate having a resin film formed on the surface is applied.

As such a pre-coated sheet to which scratch resistance is applied, it is disclosed that an inorganic material such as cerium oxide or a resin bead is added to a resin material, and a scratch-resistant film is formed on a metal plate such as aluminum. Technology (for example, Patent Documents 1 to 3). Further, it is disclosed that a coating material containing a polymer having a specific bond and a functional group and a blocked polyisocyanate is applied onto a metal plate, and is cured by irradiation with active energy such as ultraviolet rays and γ rays to produce a coated metal processed article. (for example, Patent Document 4).

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 3106498

[Patent Document 2] Japanese Patent No. 3818016

[Patent Document 3] Japanese Patent No. 4067368

[Patent Document 4] Japanese Patent Laid-Open Publication No. 6-23319

However, the resin film to which the aggregate material such as the inorganic material and the glass is added, as described in the patent documents 1 and 2, has an increased hardness. However, if the resin is repeatedly slid, the inorganic material scraped off from the film is worn to promote scratching, and thus it is impossible to cause scratching. Obtain sufficient scratch resistance. In addition, when the amount of the inorganic material added is large, the inorganic material in the film is rubbed against the mold at the time of deep drawing to cause peeling of the film, and sufficient workability of the precoated plate cannot be obtained. In the resin film to which the resin beads are added as described in Patent Document 3, since the hardness of the resin film itself which is the binder of the resin beads is not improved, the scratch resistance is insufficient, and the size of the resin beads depends on the size of the resin beads. In addition, it has a low transparency and a pear-like surface, and it is difficult to use it in the component which is required to reflect the gloss and the transparency of the metal plate color as a base. The method for producing a coated metal-worked product described in Patent Document 4 requires a step of irradiating active energy such as γ-rays, and is subjected to baking treatment after forming a coated metal sheet irradiated with active energy. Secondary film Hardened, so it is not easy to manufacture and has poor productivity.

The present invention has been made in view of the above problems, and an object thereof is to provide a sheet material and a structural member suitable for use in a household appliance product and a vehicle-mounted component, in particular, a gloss and a transparent feeling for appearance, scratch resistance, and A precoated aluminum sheet which is excellent in formability and easy to manufacture.

As a result of active research in order to solve the above problems, the inventors of the present invention have thought that the ratio of the component of the resin forming the film, particularly yttrium to oxygen, can be optimized, and the hardness of the resin itself can be improved, and the lubricity and flexibility can be improved. The property is improved to impart formability.

That is, the precoated aluminum sheet of the present invention is characterized in that a hard film having a film thickness of 0.2 μm or more and 10 μm or less is formed on one surface or both surfaces of the aluminum plate, and the hard film layer is made of 30 atom% or more and 50 atom% or less. C is contained in a range of 10 atom% or more and less than 30 atomic %, and the content of Si is 0.8 times or more and 1.2 times or less (atom). %).

By forming a resin having a concentration of C, N, Si, and O and a ratio of Si to O, the film having moderate hardness, flexibility, and lubricity is difficult to scratch and can be formed. Sex.

Further, in the precoated aluminum sheet of the present invention, it is preferred that the hard film has an absorption peak of an infrared absorption spectrum in a wavenumber range of 2100 to 2300 cm ^-1 . As described above, since the hard film has an absorption peak indicating a C, C triple bond or a C, N triple bond, the film toughness is excellent, and in particular, high moldability can be obtained.

Further, the method for producing a precoated aluminum sheet of the present invention is a method for producing the above precoated aluminum sheet, which is characterized by the step of coating a coating containing C, N, Si, O on one or both sides of an aluminum sheet. a coating step; a baking step of forming a hard film by baking the coating material at 210 ° C or higher and 280 ° C or lower.

Thus, the precoated aluminum plate coated with the hard film can be easily produced by applying a coating on an aluminum plate and performing a baking treatment to dry and harden the coating. In addition, by making the coating material contain C, N, Si, and O, the baking treatment temperature is controlled to a predetermined range, and a hard film having lubricity and moderate hardness is obtained, and pre-coating excellent in scratch resistance and moldability can be obtained. Covered with aluminum.

According to the precoated aluminum sheet of the present invention, since it is excellent in scratch resistance and moldability, it can be applied to a sheet material and a structural member other than a household appliance product and a vehicle mounting component, and is particularly suitable for a gloss and a transparent feeling for appearance. . Further, according to the method for producing a precoated aluminum sheet of the present invention, it can be produced with good productivity by coating and baking treatment.

The precoated aluminum sheet of the present invention is used as a sheet material for cutting and forming a desired shape and serving as a sheet material and a structural member other than a household appliance product and a vehicle mounting component. Hereinafter, a mode for realizing the precoated aluminum sheet of the present invention will be described.

[Pre-coated aluminum sheet]

The precoated aluminum sheet of the present invention is coated with a hard film made of a resin on the surface of an aluminum plate composed of aluminum or an aluminum alloy. In the precoated aluminum sheet of the present invention, the hard film may be formed on both sides or on one side.

Hereinafter, each element constituting the precoated aluminum sheet of the present invention will be described.

(aluminum plate)

The aluminum plate is a base material of a precoated aluminum plate, and a 1000-series industrial pure aluminum, a 3000-series Al-Mn-based alloy, and a 5000-series Al-Mg-based alloy can be used, and may be selected according to the use. In particular, when performing deep drawing and thinning, A1050, A1100, A3003, and A3004 specified in JISH4000 are recommended. In addition, A5052 and A5182 are recommended for use in applications requiring high strength. There is no particular limitation on the quality and thickness of the plate, and it can be selected according to the purpose and purpose.

The aluminum plate preferably performs a substrate treatment on the surface to form a substrate treatment layer between the aluminum film and the hard film. By the base treatment layer, the adhesion between the aluminum plate and the hard film is improved, and the corrosion resistance of the aluminum plate is improved. As the substrate treatment layer, a conventionally known film containing one or more of Cr, Zr, and Ti can be applied. For example, a chromate chromate film, a chromate chromate film, a zirconium phosphate film, a zirconia film, a titanium phosphate film, a coating type chromate film, a coated zirconium film, or the like can be suitably used. Further, an organic component may be contained in the films as needed. Based on concerns about environmental problems in recent years, it is preferred to use a chromate film of phosphoric acid containing no hexavalent chromium, a zirconium phosphate film, a zirconium oxide film, a titanium phosphate film, and a coated zirconium film. The thickness of the underlayer treatment layer is preferably about 10 to 50 mg/m ^{2 in terms} of the adhesion amount of Cr, Zr, and Ti to the aluminum plate (in terms of Cr, zr, and Ti). When the amount of adhesion is less than 10 mg/m ² , the entire surface of the aluminum plate cannot be uniformly coated, and the effect cannot be sufficiently obtained. On the other hand, when the adhesion amount exceeds 50 mg/m ² , the undercoat layer itself is liable to be cracked. The values of Cr, Zr, and Ti can be measured relatively easily and quantitatively, for example, by a fluorescent X-ray method. Therefore, quality management of the aluminum plate can be performed without hindering productivity.

(hard film)

In the precoated aluminum sheet, the hard film is provided to impart scratch resistance by utilizing the hardness thereof, and imparts formability by flexibility and lubricity. The hard film is formed to have a film thickness of 0.2 μm or more and 10 μm or less, and is composed of a resin containing carbon (C), nitrogen (N), cerium (Si), and oxygen (O) in a predetermined amount.

In the precoated aluminum sheet of the present invention, in order to obtain sufficient scratch resistance, the pencil hardness measured by the hard film according to the specification of JIS 5600-5-4 is preferably 4H or more in terms of damage. The hardness of the hard film can be obtained by controlling the resin component forming the hard film as will be described later.

(film thickness: 0.2 μm or more and 10 μm or less)

The film thickness of the hard film is set to 0.2 μm or more and 10 μm or less. Film thickness When it is less than 0.2 μm, the effect of scratch resistance cannot be sufficiently obtained in the precoated aluminum sheet. On the other hand, even if the film thickness exceeds 10 μm, it is difficult to obtain further improvement of the effect, and it is easy to crack due to the hardness of the hard film. Further, by setting the film thickness to the above range, a hard film can be continuously formed on a roll-shaped aluminum plate by a roll coater, which is excellent in productivity and cost. When the film thickness exceeds 10 μm, the feed roller of the roll coater is insufficient in the drawability of the paint, and the variation in film thickness is remarkably large. Conversely, when the film thickness is less than 0.2 μm, it is necessary to increase the pressure between the feed roller and the coating roller, and the roller is easily worn.

The hard coating film contains C in a range of 30 atom% or more and 50 atom% or less, and contains N, Si, and O in a range of 10 atom% or more and less than 30 atom%, respectively, and 0.8 times or more of 1.2. A resin containing Si in a content ratio (atomic %) or less is formed. Further, the hard film preferably has an absorption peak of an infrared absorption spectrum in a wavenumber range of 2100 to 2300 cm ^-1 . Such a hard film is formed of a silicone resin, a modified epoxy resin or a cerium-based resin, and as described later, a resin coating material obtained by mixing and preparing a resin material can be applied to an aluminum plate and baked. get.

(C: 30 atom% or more and 50 atom% or less)

C (carbon) is a main component of a resin which forms a hard film, and if it is contained in a large amount, the resin is softened, and the elongation is improved. Further, C is a component which imparts lubricity to the resin. When the C content is less than 30 atom%, the hard film is excessively hard, and it is impossible to follow the deformation of the aluminum plate during molding, which is liable to occur. Peeling or causing defects such as cracks. On the other hand, when the C content exceeds 50 atom%, the hardness of the hard film is insufficient, and scratch resistance cannot be obtained by precoating the aluminum plate.

(N: 10 atom% or more and less than 30 atom%)

N (nitrogen) is a component that imparts flexibility and lubricity to a resin that forms a hard film. When the N content is less than 10 atom%, the flexibility of the hard film is insufficient, and cracking and peeling of the film occur during molding, and the lubricity is insufficient, and the slidability with the mold during molding is inferior, and moldability cannot be obtained. On the other hand, when the N content is 30 atom% or more, the flexibility of the hard film is excessive and the hardness is insufficient, and scratch resistance cannot be obtained.

(Si, O: 10 atom% or more and less than 30 atom%, respectively)

Niobium (Si) and oxygen (O) are components which impart hardness to the resin forming the hard film. When the content ratio of Si and O is less than 10 atom%, the hardness of the hard film is insufficient, and scratch resistance cannot be obtained. On the other hand, when the content ratio of Si and O is 30 atom% or more, the hardness of the hard film becomes excessive and the moldability is lowered.

(Si/O ratio: 0.8~1.2)

In the resin forming the hard film, the Si content (atomic %) is 0.8 times or more and 1.2 times or less with respect to the O content (atomic %). When Si is more than 1.2 times more than O, the hard film becomes too hard and the formability is lowered. On the other hand, when Si is less than 0.8 times with respect to O, even if the above content is satisfied When the rate is 10 atom% or more, the hardness of the hard film is remarkably lowered, and scratch resistance is not obtained, and defects such as cracking of the hard film may occur during molding.

The resin forming the hard film of the precoated aluminum sheet of the present invention may contain H (hydrogen) in addition to C, N, Si, and O. The content of H is not particularly limited, but is preferably less than 10 atom%, that is, the total content of C, N, Si, and O is preferably more than 90 atom%.

The content ratio of C, N, Si, and O formed in the hard film on the surface of the precoated aluminum plate can be, for example, by glow discharge luminescence analysis (GD-OES) method and X-ray photoelectron spectroscopy (XPS, or ESCA) method. It is obtained by measurement. When the depth from the surface on which the hard film is formed of the precoated aluminum sheet to the thickness of the hard film is measured, the composition of the hard film such as C can be detected, and the Al of the aluminum plate component or the additive element of the aluminum alloy can be detected. Since the elements detected as components of the hard film are C, N, Si, and O, the atomic ratio (atomic %) may be measured and managed.

(Absorption peak of infrared absorption spectrum: wave number 2100~2300cm ^-1 )

A resin having a C, C triple bond and a C, N triple bond, for example, a nitrile rubber, because of its high toughness, contains a hard film of the resin, which has sufficient hardness and imparts a particularly high formability to the precoated aluminum plate, and is suitable for A formed member having a large degree of processing like a deep drawing is performed. These bonds have absorption peaks in the infrared absorption spectrum in the range of wave number 2100 to 2300 cm ^-1 , and therefore the precoated aluminum plate of the present invention preferably has an absorption peak in this range. Such a hard film can be obtained by baking a resin having a predetermined composition as described above, and baking it at a relatively high temperature or for a long period of time as described in the production method described later. That is, it is presumed that the hardening by heating is sufficiently performed, whereby the C, C triple bond and the C, N triple bond are generated in the resin. In particular, by using a coating material containing an alkynyl group, a nitrile group-containing oxime resin, and an alkali phthalate resin, a resin having a triple bond in a unit structure can be obtained by a crosslinking reaction by heating. A hard film having high toughness and heat stability is preferred.

The resin coating for forming a hard film is preferably continuously coated by a roll coater based on the productivity and cost of the precoated aluminum sheet, and is baked in a baking oven for a short time of about 20 to 60 seconds. Hardened material. Examples of the material of the resin coating material include a methyl oxime resin, a phenyl sulfonium resin, an aminoalkyl oxirane resin, an epoxy-modified oxirane resin, a urethane-modified oxime resin, and the like. Acrylate epoxy resin, alkali phthalate-containing resin, and the like.

The hard film contains the above-mentioned C, N, Si, and O resins, but may contain other components as needed. For example, in order to further improve press formability, it may contain one or more kinds of lubricants such as palm oil, carnauba wax, polyethylene wax, and microcrystalline wax. In addition, in order to ensure the paintability of the coating and the general properties of the precoated metal sheet, the hard film may also contain a pigment, a pigment dispersant, a fluidity regulator, a leveling agent, a boiling agent, and an antiseptic which are generally used. Agent, stabilizer, etc.

[Manufacturing method of pre-coated aluminum sheet]

Next, a method of manufacturing a precoated aluminum sheet will be described. The method for manufacturing the precoated aluminum sheet of the present invention is carried out by the following steps: one of the aluminum sheets a coating step of applying a coating containing C, N, Si, and O on the surface or both sides; and a baking step of forming a hard coating on the coated coating at 210 ° C or higher and 280 ° C or lower.

(coating step)

The coating of the coating may be performed by any one of a brush coater, a roll coater, a curtain coater, a curtain roll coater, an electrostatic coater, a knife coater, a die coater, etc., but Particularly preferred is a roll coater which is uniform in coating amount and easy to handle. Further, in consideration of the conveyance speed of the aluminum plate, the rotation direction of the roll coater, the number of rotations, and the like, the coating amount is appropriately adjusted so that a hard film having a desired thickness in the range of 0.2 to 10 μm is formed on the surface of the aluminum plate.

A degreasing step of degreasing the surface of the aluminum plate may also be performed before the coating step. For example, the surface of the aluminum plate is sprayed with an aqueous alkali solution and then washed with water.

Further, a substrate treatment step of forming a substrate treatment layer on the surface of the aluminum plate may be performed before the coating step. For example, the aluminum plate after the degreasing step is subjected to a chromate treatment to form a chromate film of phosphoric acid.

(baking step)

The aluminum plate coated with the coating is subjected to a baking treatment to harden the coating material to form a hard film. The baking temperature is preferably from 210 ° C to 280 ° C. If the temperature is within this range, a hard film can be obtained by baking for a short time of 20 to 60 seconds. Also, the baking temperature is the highest arrival of the aluminum plate temperature. When the baking treatment time is less than 20 seconds, there is insufficient baking. On the other hand, even if the baking treatment is performed for more than 60 seconds, the baking temperature is not further hardened, and the productivity per unit time is lowered. Further, when the baking temperature was less than 210 ° C, the baking of the coating was not sufficient when the baking treatment was carried out for 20 seconds, and the hardness of the hard film was insufficient. The baking temperature is better than 230 ° C, and the baking treatment time is 20 to 50 seconds. According to such a relatively high temperature baking treatment, it is easy to form a resin having a C, C triple bond and a C, N triple bond. However, if the baking temperature exceeds 280 ° C, the coating starts to decompose, so the hardness of the hard film is rather lowered. Or when the baking temperature is less than 210 ° C, a hard film can be obtained by performing a long-time baking treatment. Specifically, if the baking treatment time is 1 hour, the baking temperature can be set to 130 ° C, and in addition, when the baking temperature is 150 ° C, a resin having a C, C triple bond and a C, N triple bond can be formed. . The baking treatment can be carried out using a hot air furnace, an induction heating furnace, a near infrared ray furnace, a far infrared ray furnace, an energy ray hardening furnace, or the like.

[Examples]

The embodiment for carrying out the present invention has been described above. Hereinafter, an embodiment in which the effects of the present invention is confirmed will be specifically described in comparison with a comparative example which does not satisfy the requirements of the present invention. Further, the present invention is not limited by the embodiment.

[Production of test materials] (base treatment of aluminum plate)

As the aluminum plate, a JIS 5182H18 material having a plate thickness of 0.5 mm was used. After the aluminum plate was degreased with an aqueous alkali solution, the phosphoric acid chromate treatment was carried out to form a chromate film of phosphoric acid having a molar ratio of 20 mg/m ² on both surfaces.

(formation of hard film)

A resin coating having a different composition is applied, and one side of the aluminum plate after the substrate treatment is applied by a roll coater. The aluminum plate was heated in a continuous furnace so that the maximum temperature reached by the aluminum plate was 30 seconds for the baking temperature shown in Table 1 (the sample No. 14 was 1 hour), and baked to prepare a pre-coating. Test materials for aluminum plates. In the test material No. 25, the film of the invention of Patent Document 1 is prepared so as to be cured (solid content), and 80 parts by mass of the epoxy resin (SiO ₂ ) is added in an amount of 20 parts by mass. The film.

[Measurement of hard film]

The film thickness, the composition, and the infrared absorption spectrum of the obtained film of the test material were measured and shown in Table 1. However, in the test material No. 27, since the appearance was poor as observed on the film, the observation of the infrared absorption spectrum and the evaluation described later were not performed, and in Table 1, "-" (the infrared absorption spectrum was "(-)")).

(film thickness and composition of hard film)

For the test material, the film thickness was measured using a vortex type film thickness meter. Further, GD-OES is used to measure the depth of the film from the surface of the film to the film thickness corresponding to the film, and all the elements contained in the film are detected, and the atomic ratio of C, N, Si, and O in the depth direction is calculated. The average value.

(Infrared absorption spectrum of hard film)

For the film of the test material, the infrared absorption spectrum was observed by a Fourier transform infrared spectrophotometer (FT-IR). The peak observed in the range of wave number 2100 to 2300 cm ^-1 is indicated by "○", and the observed person is indicated by "-", and is shown in Table 1.

[Evaluation] (hardness of hard film)

For the test materials, the pencil hardness of the film was measured by damage determination in accordance with JIS K5600-5-4, and is shown in Table 1. Those with a pencil hardness of 4H or higher are qualified.

(scratch resistance)

On the surface of the film to be tested, the steel wool was pressed at 100 gf to slide back and forth 30 times at a distance of 10 cm, and the surface state of the film was visually observed. Those who have no obvious scratches are qualified, those with small scratches are indicated by “○”, those who are completely scratched are indicated by “◎”, and are shown in Table 1, respectively, and it is confirmed that the scratches are bad, "X" is shown in Table 1.

(deep formability)

As the formability, the evaluation of the draw formability was performed. Using an Erichsen tester, the surface on the side where the film was formed was brought into contact with the forging die to fix the test piece, and the surface was passed as the outside of the molded article. A cylindrical punch of 43 mm was drawn deep at a depth of 20 mm, and the surface state of the film was visually observed. The film was not peeled and the scratches were not acceptable. The film was not peeled off, but the scratches were observed with "○", and the scratches were not observed with "◎". The abnormality is bad, and is shown in Table 1 as "X".

As shown in Table 1, in the test materials No. 1 to 14, since the respective contents of the C, N, Si, and O, and the Si/O ratio and the film thickness of the film satisfy the range of the present invention, sufficient hardness can be obtained. And a hard film of formability, which is excellent in scratch resistance and deep drawability. Moreover, the coating property and the corrosion resistance are practically not problematic by the production and evaluation of the test material. In particular, by the high-temperature baking treatment, the sample No. 13 having an absorption peak derived from the infrared absorption spectrum of the C, C triple bond and the C, N triple bond is excellent in both scratch resistance and deep drawability. .

On the other hand, the test materials No. 15 to 24 were comparative examples in which the film components were outside the scope of the present invention. In the test material No. 15, since the film C was insufficient, the film was too hard and the lubricity was lowered, and as a result, the draw formability could not be obtained. Since the sample No. 16 was excessive in the film C, the hardness of the film was insufficient, and scratch resistance could not be obtained.

Since the sample No. 17 was insufficient in N of the film, flexibility and lubricity were insufficient, and deep drawability could not be obtained. On the contrary, in the test material No. 18, since the N of the film was excessive, the flexibility was excessive and scratch resistance could not be obtained.

In the test materials Nos. 19 and 21, since the Si and O of the film were insufficient, the hardness of the film was remarkably lowered, and scratch resistance and deep drawability were not obtained. In the test materials No. 20 and 22, since the Si and O of the film were excessively excessive, the film was too hard and the deep formability could not be obtained.

In the test material No. 23, since the Si in the film was too small relative to O, the film hardness was remarkably lowered, and scratch resistance and deep drawability could not be obtained. For the test material No. 24, since the Si in the film is excessive with respect to O, the skin The film is too hard to obtain deep drawability.

In the test material No. 25, the test material of the film of the invention of Patent Document 1 was obtained, and hardness was obtained by adding cerium oxide to the resin material, but abrasion was observed in the scratch resistance evaluation, and scratch resistance could not be obtained. Sex.

The test materials No. 26 and 27 were comparative examples in which the film component was within the scope of the present invention, but the film thickness was outside the range. For the test material No. 26, the film thickness was insufficient, and scratch resistance could not be obtained. On the other hand, the test material No. 27 formed an excessively thick film, and the film was cracked and the appearance was poor.

Claims (3)

A precoated aluminum plate characterized by forming a precoated aluminum plate having a film thickness of 0.2 μm or more and 10 μm or less on one or both sides of an aluminum plate, wherein the hard film is 30 atom% or more and 50 atoms or less The range of % or less contains C, and is contained in a resin containing N, Si, and O in a range of 10 atom% or more and less than 30 atom%, and the Si content (atomic %) is 0.8 times or more and 1.2 of the above-mentioned O. Less than the following. The precoated aluminum sheet according to claim 1, wherein the hard film has an absorption peak of an infrared absorption spectrum in a wavenumber range of 2100 to 2300 cm ^-1 . A method for producing a precoated aluminum sheet, which is a method for producing a precoated aluminum sheet according to claim 1 or 2, characterized in that: coating a coating containing C, N, Si, O on one or both sides of the aluminum sheet a coating step; a baking step of forming the hard coating by baking the coating material at 210 ° C or higher and 280 ° C or lower.