KR101786733B1 - Aluminium plate, manufacturing method thereof, and cooking vessel manufactured by using the same - Google Patents

Abstract

The present invention relates to an aluminum plate having an anodized coating layer, a subcoating layer and an upper coating layer sequentially laminated on an aluminum substrate having protrusions protruding from the surface.

Description

TECHNICAL FIELD [0001] The present invention relates to an aluminum plate, a method of manufacturing the same, and a cooking vessel manufactured using the same. BACKGROUND OF THE INVENTION [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum plate used for manufacturing a cooking vessel such as an inner pot for a rice cooker, a frying pan and the like, a method of manufacturing the same, and a cooking vessel made of the plate.

Generally, the cooking container used for cooking food is made of aluminum, stainless steel, copper, enamel, scum or the like. Such a cooking vessel must have heat resistance to withstand heat, and non-stickiness is required to prevent food from sticking to the inner surface of the cooking vessel during cooking. In addition, when the inner surface of the cooking container is scratched by the cooking tool during cooking and the harmful substances are discharged from the cooking container, the abrasion resistance of the cooking container must be ensured so that the food is not contaminated by the harmful substances.

Such a cooking vessel is generally manufactured through the following two methods known in the art.

First, in the post-coat method, an aluminum substrate is pressed into a cooking vessel shape, and then a coating layer is formed on the aluminum substrate. Specifically, there is provided a method for manufacturing a cooking container, comprising the steps of: forming a main body of a cooking vessel by pressing an aluminum base material into a cooking vessel shape; sandblasting the inner surface of the cooking vessel main body to form a fine uneven portion; And forming a coating layer. On the other hand, the pre-coat method is to form a coating layer on an aluminum substrate before press-processing the aluminum substrate into a cooking vessel shape. Specifically, the method includes electrochemically or chemically etching the surface of the aluminum substrate to form fine irregularities, forming a coating layer on the fine irregularities, and pressing the aluminum substrate having the coating layer formed thereon into a cooking vessel shape Thereby forming a cooking vessel.

Here, the coating layer is formed by using polytetrafluoroethylene (PTFE), which is generally excellent in non-adhesive property, heat resistance and corrosion resistance, so as to secure heat resistance, non-stick property and abrasion resistance of the cooking container. However, PTFE has low adhesion to aluminum substrates. Therefore, even when the coating layer is present on the inner surface of the main body of the cooking vessel, the non-sticking property and the wear resistance effect of the cooking vessel are not sufficiently exhibited.

In order to solve such a problem, conventionally, a heat-stable binder (for example, polyamide-imide) excellent in adhesion to an aluminum base material other than PTFE (for example, (Hereinafter referred to as a " undercoat layer ") is formed by using a coating layer composition that further comprises an aluminum-based coating layer (e.g., polyimide, polyether sulfone, polyphenylene sulfide, etc.) . However, since the heat-stable bonding agent has a high surface energy and a high reaction activity, the non-tackiness and corrosion resistance are lower than those of PTFE. Therefore, even when the adhesion between the aluminum substrate and the upper coating layer is enhanced by the lower coating layer, when the upper coating layer is scratched or abraded by the cooking pot or the cleaning tool to expose the lower coating layer, the non- . In addition, when the cooked container is exposed to a high temperature for a long time, the heat-stable bonding agent in the undercoat layer is thermally decomposed to cause cracking of the coating film or whitening of the coating film. In addition, corrosive substances such as salt penetrate into the undercoat layer during cooking, Or peeling occurred.

In order to solve the above problems, it is an object of the present invention to provide an aluminum plate excellent in heat resistance, corrosion resistance, scratch resistance, abrasion resistance and non-stick property and a method of manufacturing the same.

Further, the present invention provides a cooking vessel excellent in heat resistance, corrosion resistance, scratch resistance, abrasion resistance and non-stick property by processing the aluminum plate into a container shape.

The present invention provides an aluminum plate material which can be formed into a cooking vessel or the like by press working, the aluminum plate material comprising: an aluminum substrate having protrusions protruding from the surface; An anodic oxidation coating layer formed on the aluminum substrate; A lower coating layer formed on the anodized coating layer; And an upper coating layer formed on the lower coating layer, wherein the lower coating layer comprises (a) 100 parts by weight of polytetrafluoroethylene (PTFE), (b) a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer and tetra (C) 5 to 20 parts by weight of at least one fluorocarbon copolymer selected from the group consisting of fluoroethylene-hexafluoropropylene copolymer and fluoroethylene-hexafluoropropylene copolymer, and (c) a thermosetting binder.

Herein, the undercoat layer composition may include an inorganic filler for strengthening a coating film, a flake-like filler, or both. The content of the inorganic filler and the flake-like filler may be 1 to 10 parts by weight based on 100 parts by weight of the polytetrafluoroethylene.

It is preferable that the cross-sectional shape of the protrusion includes a section where the length in the width direction becomes longer as the distance from the aluminum base material increases.

In addition, the top coat layer is preferably formed of a top coat layer composition comprising polytetrafluoroethylene (PTFE).

The present invention also provides a method of manufacturing the above-described aluminum plate material, comprising the steps of: (S100) forming protrusions extending from the surface of the aluminum substrate; (S200) forming an anodized coating layer on the aluminum substrate in step S100; (S300) applying a subcoat layer composition on the anodized film layer, firing the subcoat layer composition, and cooling at a rate of 3 to 6 ° C / sec to form a subcoat layer; And (S400) coating and baking an upper coating layer composition containing polytetrafluoroethylene on the lower coating layer, and cooling the coating layer at a rate of 3 to 6 ° C / sec to form an upper coating layer.

Here, the step S100 may include: (S110) processing the aluminum base material into a hair line; (S120) a step of immersing the aluminum substrate obtained in the step S110 in an aqueous sulfuric acid solution (concentration: 5 to 25%, temperature: 60 to 80 ° C) for 5 to 10 minutes to degrease the aluminum substrate; (S130) The aluminum substrate obtained in the step S120 is immersed in a mixed solution of sodium hydroxide (concentration: 10 to 100 g / l) and zinc oxide (concentration: 5 to 50 g / Zincate for 120 seconds to coat the surface of the aluminum substrate with zinc; (S140) The zinc-coated aluminum substrate obtained in the step S130 is immersed in a mixed solution of ammonium chloride (concentration: 10 to 100 g / l) and hydrochloric acid halide solution (concentration: 10 to 100 g / l) , Electrolytic etching treatment for 1 to 5 minutes at a temperature of 20 to 60 캜, a voltage of 5 to 25 V, and a current density of 10 to 60 A / dm ² .

In step S200, the aluminum substrate obtained in step S100 is immersed in an aqueous nitric acid solution (concentration: 5 to 30%, temperature: 10 to 35 ° C) for 1 to 10 minutes to remove a reducing metal salt from the aluminum substrate A desmut step for removing the liquid; (S220) An aluminum substrate of the step S210 is applied with a voltage of 3 to 15 V in an aqueous sulfuric acid solution (concentration: 5 to 25%, temperature: 10 to 35 ° C) to form an oxide film on the surface of the aluminum substrate And an anodizing step of subjecting the resultant to an anodizing treatment.

In addition, the present invention provides a cooking vessel manufactured by press-working the aforementioned aluminum plate into a container shape.

The aluminum plate according to the present invention is superior in heat resistance, scratch resistance, corrosion resistance, abrasion resistance and non-sticking property to conventional aluminum plate materials including a lower coating layer containing a heat-stable binder because a heat- Is excellent.

1 is a sectional view showing an aluminum plate according to an example of the present invention.
2 is a sectional view showing an aluminum plate according to another example of the present invention.
3 is a cross-sectional view of a cooking vessel manufactured using the aluminum plate material of the present invention.

Hereinafter, the present invention will be described in detail.

The present invention relates to an aluminum plate material which can be formed into a shape of a cooking vessel (for example, an inner pot for an electric rice cooker, a pan, a frying pan, etc.) through a press working, and is made of polytetrafluoroethylene (PTFE) and tetrafluoroethylene (PFA) and / or tetrafluoroethylene-hexafluoropropylene copolymer (FEP) are mixed together, and the mixing ratio thereof is controlled at a specific ratio to form a lower coating layer .

Polytetrafluoroethylene (PTFE) has a melting point from about 320 to 340 ℃, the melt viscosity is from about 10 ⁸ to 10 ¹² Pa · sec. On the other hand, the tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and the tetrafluoroethylene-hexafluoropropylene copolymer (FEP) have lower melting point and lower melting point than PTFE. That is, the PFA has a melting point of about 302 to 310 ° C, a melt viscosity of about 10 ³ to 10 ⁴ Pa · sec, an FEP having a melting point of about 260 to 282 ° C and a melt viscosity of about 10 ⁴ to 10 ⁵ Pa · sec to be. Therefore, when PTFE is mixed with PFA and / or FEP as a component of the undercoat layer composition, the present inventors have found that when firing, PFA and FEP are melted before PTFE, and when the molten PFA and / or FEP are not melted, It has been found that a lower coating layer having a denser crystal structure than that of the porous network PTFE coating can be formed when the PTFE is melted after reaching the melting point and then they are cooled.

However, the inventors of the present invention found that the crystal structure of the undercoat layer varies depending on the mixing ratio of PTFE, PFA and / or FEP, thereby changing the adhesive strength, corrosion resistance, heat resistance and non-tackiness of the coating layer, (See Tables 2, 4 and 6 below).

Accordingly, the present invention provides a method for producing a PTFE-based thermosetting resin composition, which comprises the steps of adjusting the mixing ratio of PTFE, PFA and / or FEP to 100: 5 to 20 by weight, Corrosion resistance, heat resistance and non-stickiness can be generally improved while maintaining the adhesive strength of the undercoating layer to a level similar to that of the prior art. Further, since the present invention excludes the use of the heat-stable binder as a component of the undercoat layer composition, problems caused by the use of the heat-stable binder, that is, lowering of the non-stickiness of the aluminum plate due to exposure of the undercoat layer, The coating film whitening, the coating film whitening, and the peeling do not occur due to thermal decomposition of the coating film, and therefore, non-stickiness, heat resistance, corrosion resistance and scratch resistance can be increased. In addition, since the undercoat layer is mechanically bonded to the protruding portion elongated from the surface of the aluminum base material, the present invention is similar in adhesion to an aluminum base material without using a thermally stable binder. In addition, since the undercoat layer of the present invention has a dense crystal structure, it is difficult for the corrosion-inducing material (e.g., chloride ion) to penetrate into the undercoat layer, and thus the corrosion resistance can be significantly improved as compared with the conventional undercoat layer.

<Aluminum plate material>

Referring to FIGS. 1 and 2, the aluminum plate 100 of the present invention includes an aluminum substrate 10, an anodized coating layer 20, a subcoat layer 30, and an upper coating layer 40.

The aluminum substrate 10 of the present invention is not particularly limited as long as it is a substrate in the form of a sheet containing aluminum, for example, an aluminum plate; Aluminum alloy plate; And a clad plate material obtained by bonding aluminum or an aluminum alloy with at least one dissimilar metal selected from the group consisting of stainless steel, copper and titanium.

The aluminum base 10 has a protrusion 11 protruding from the surface. The protrusions 11 are arranged in the width direction of the aluminum base material in a continuous or discontinuous linear shape. The cross-sectional shape of the protruding portion is not particularly limited. As shown in an enlarged part of FIGS. 1 and 2, a section in which the length of the protruding portion in the width direction 11a increases as the cross-sectional shape of the protruding portion moves away from the aluminum base Quot; hanging jaws &quot;), and may be, for example, a Ω shape or the like, the width and / or height thereof may be regular or irregular.

In this case, the projecting portion 11 not only increases the specific surface area of the aluminum base material but also can act as an anchor. Therefore, not only the contact area of the aluminum base 10 with the undercoat layer 30 to be described later is increased by the protrusions 11 but also the lower undercoat layer 30 is formed at the engagement protrusion portion of the protrusion 11 Anchoring, the lower undercoat layer 30 can be physically and structurally more firmly bonded (adhered) to the aluminum substrate 10. Therefore, the aluminum plate according to the present invention can improve the wear resistance and the durability due to the increase of the adhesion force between the aluminum substrate and the undercoat layer.

The surface roughness Ra of the protrusions 11 is not particularly limited, but may be about 1 to 5 占 퐉, preferably about 1.5 to 4 占 퐉. If the surface roughness of the protrusions 11 is within the above range, the specific surface area of the aluminum base material may be further increased, and the adhesive force with the undercoat layer 30 may further be increased.

The aluminum plate 100 of the present invention includes an anodized coating layer 20. The anodic oxide coating layer 20 is an inert coating layer formed on the aluminum substrate 10, preferably corresponding to the shape of the protruding portion 11 of the aluminum substrate 10, and can improve the corrosion resistance of the aluminum plate.

The aluminum plate 100 of the present invention includes a lower coating layer 30. The undercoat layer 30 is a layer formed on the outer surface of the anodized oxide layer 20 and adheres an upper coating layer 40 to be described later to the surface of the anodized oxide layer 20, The non-stick property and the abrasion resistance can be improved, and furthermore, the heat resistance, the non-stick property and the abrasion resistance of the cooking container manufactured using the present aluminum plate material can be improved.

The thickness of the undercoat layer is not particularly limited, but is preferably about 10 to 40 占 퐉, more preferably about 15 to 30 占 퐉. When the thickness of the undercoat layer is within the above range, cracking of the coating film is minimized and the corrosion resistance and wear resistance of the aluminum plate material can be improved. Further, since the undercoat layer is uniformly formed on the surface of the anodic oxide coating layer as a whole, The adhesion between the upper coating layers can be improved.

The composition for forming such a lower coating layer 30 (hereinafter referred to as a &quot; lower coating layer composition &quot;) does not contain a thermostable binder as described above. That is, in the case of the present invention, the heat-stable binder is excluded as one component of the undercoat layer composition. Accordingly, unlike the prior art, the present invention has been made to solve the problems caused by the thermal stability bonding agent, namely, the deterioration of the non-stickiness of the aluminum plate due to the exposure of the undercoat layer and the cracking of the coating film, the whitening of the coating film, The non-adhesive property, the heat resistance and the corrosion resistance of the cooking container can be improved in the production of the cooking container using the present invention.

The heat-stable binder excluded from the present invention is a polymeric material that chemically bonds with an oxide, hydroxide, carbonate, or the like formed on the surface of an aluminum substrate to firmly adhere the undercoat layer to the surface of the aluminum substrate. In this technical field, Is not particularly limited as long as it can be adhered to an aluminum substrate and is not pyrolyzed at a temperature of about 150 캜 or more. Examples thereof include polyamide-imide resins, polyimide resins, polyether sulfone resins, and polyphenylene sulfide resins.

Specifically, the polyamide-imide resin is a polymer containing an amide group and an imide group in the main chain of the molecule, and examples thereof include an amide group-containing aromatic diamine and an aromatic tetracarboxylic acid (e.g., pyromellitic acid ); &Lt; / RTI &gt; A polymer obtained by polymerization of an aromatic trivalent carboxylic acid (e.g., anhydrous trimellitic acid) with a diamine (e.g., 4,4-diaminophenyl ether); A polymer obtained by polymerizing an aromatic trivalent carboxylic acid (e.g., trimellitic anhydride) with a diisocyanate (e.g., diphenylmethane diisocyanate); A polymer polymerized by polymerization reaction of an aromatic imide ring-containing dibasic acid and a diamine, and specific examples thereof include polyamide-imide containing a repeating unit represented by the following formula (1).

[Chemical Formula 1]

The polyimide resin is a polymer containing an imide group (-CO-N-CO-) in the main chain of the molecule. For example, a polymerization reaction of an aromatic tetracarboxylic anhydride (such as pyromellitic anhydride) , And specific examples thereof include polyimide containing a repeating unit represented by the following formula (2), and the like.

(2)

The polyether sulfone resin is a polymer containing a sulfonic group and an ether group in the main chain of the molecule, for example, a polymer obtained by condensation polymerization of dichlorodiphenyl sulfone and dihydroxydiphenyl sulfone; A polymer obtained by polycondensation of dichlorodiphenyl sulfone and bisphenol A, and specific examples thereof include polyethersulfone containing a repeating unit represented by the following formula (3).

(3)

The polyphenylene sulfide resin may be a polymer polymerized by polycondensation of sodium sulfide and p-dichlorobenzene. Specific examples thereof include polyphenylene sulfide containing a repeating unit represented by the following formula (4).

[Chemical Formula 4]

However, the undercoat layer composition according to the present invention is not limited to the above-mentioned thermally stable binder, but also includes (a) polytetrafluoroethylene (PTFE), (b) tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer Based copolymer (PFA) and tetrafluoroethylene-hexafluoropropylene copolymer (FEP), wherein the fluorocarbon-based fluorocarbon-based copolymer is used in an amount of 100 parts by weight based on 100 parts by weight of the polytetrafluoroethylene, The content of the copolymer is controlled within a range of about 5 to 20 parts by weight. If the content of the fluorocarbon-based copolymer is less than 5 parts by weight, the adhesiveness is lower than that of the conventional undercoat layer and the corrosion resistance improvement effect is insufficient. When the content of the fluorocarbon copolymer exceeds 20 parts by weight, The smoothness of the coating film due to the formation of the unevenness on the undercoat layer may be lowered when the upper coat layer is formed.

According to the present invention, the undercoat layer composition may further include at least one additive selected from the group consisting of an inorganic filler (31) for strengthening a film and a flake filler.

As shown in FIG. 2, the inorganic filler 31 enhances the abrasion resistance of the undercoat layer. Further, the inorganic filler 31 acts as a wedge for fixing the undercoat layer 30 and the overcoat layer 40 to each other, The adhesion between the coating layer and the upper coating layer can be increased. Examples of the inorganic filler for coating film 31 include silicon carbide, silicon nitride, boron nitride, diamond and the like, which may be used alone or in combination of two or more.

The shape of the inorganic filler for coating film is not particularly limited and may be, for example, spherical, blocky or acicular.

The particle size of the inorganic filler for coating film is not particularly limited, but is preferably about 1 to 100 mu m, more preferably about 5 to 50 mu m. If the particle size of the inorganic filler for film reinforcement is within the above range, the abrasion resistance of the undercoat layer and the adhesion between the undercoat layer and the overcoat layer are improved, and the smoothness of the coat is not reduced.

The content of the inorganic filler for coating film is not particularly limited, but is preferably about 1 to 10 parts by weight based on 100 parts by weight of polytetrafluoroethylene (PTFE). If the content of the inorganic filler for coating film is within the above range, the abrasion resistance of the undercoat layer can be further improved.

In the undercoat layer composition, the flake-like filler can optically impart an apparent beauty to the aluminum plate material. The flake-like filler usable in the present invention is not particularly limited and may be, for example, a mica particle, a mica particle coated with a pigment, a metal flake or the like, and these may be used singly or in combination.

The content of such flake-like filler is not particularly limited, but is preferably about 1 to 10 parts by weight based on 100 parts by weight of polytetrafluoroethylene (PTFE). If the flake-like filler is used within the above-mentioned content range, a coating film having an optically beautiful appearance can be formed on the aluminum plate without deteriorating physical properties such as abrasion resistance and adhesiveness of the undercoat layer.

The particle size of the flaky filler is not particularly limited, but may preferably be about 5 to 100 mu m, more preferably about 10 to 50 mu m. If the particle size of the flaky filler is within the above range, the optical effect of the coating film is increased without lowering the smoothness of the coating film, thereby improving the aesthetics of the aluminum plate material.

The undercoat layer composition may contain pigments known in the art, such as titanium dioxide, carbon black, ultramarine blue, iron oxide, and the like, in order to impart aesthetic appeal to the aluminum plate, And the like.

In addition to the above-mentioned components, the undercoat layer composition may further contain additives known in the art such as a dispersant, a wetting agent, a wetting agent, a wetting agent, An anti-settling agent, a pH adjusting agent, and the like. At this time, one or more additives may be added to the composition in a content known in the art.

The aluminum plate 100 according to the present invention includes an upper coating layer 40. The upper coating layer 40 is a layer formed on the lower coating layer 30 as shown in FIGS. 1 and 2, and can improve the heat resistance, the non-sticking property, and the wear resistance of the aluminum plate material. Accordingly, when the cooking vessel manufactured according to the present invention is used, it is possible to prevent the harmful components from being discharged from the vessel during cooking to prevent contamination of the food, and to prevent corrosion of the vessel by the food.

The thickness of the top coat layer 40 is not particularly limited, and is preferably about 5 to 30 占 퐉, and more preferably about 10 to 20 占 퐉. When the thickness of the upper coating layer is within the above range, the abrasion resistance of the aluminum plate material is further improved, and the wear resistance of the cooking container can be further improved.

The material for forming the top coat layer 40 (hereinafter, the top coat layer composition) is not particularly limited. However, considering the case where the present invention is manufactured from a cooking vessel such as a frying pan, Ethylene (PTFE) is preferred. This is because the frying pan is exposed to a high temperature by direct heating such as a gas fire unlike an inner cooker for an electric rice cooker and therefore the PFA top coat layer and the FEP top coat layer continue to be heated to a temperature higher than the melting point thereof due to low melting point and melt viscosity, If exposed, the cookware may easily become scratched. Therefore, in order to prevent such a problem, it is preferable to form the top coat layer using PTFE having a relatively high melting point and high melt viscosity.

&Lt; Method of producing aluminum plate &

A method of manufacturing an aluminum plate according to an embodiment of the present invention will be described. However, the present invention is not limited to the following production methods, and the steps of each step may be modified or optionally mixed as necessary.

According to a preferred embodiment of the method for producing the aluminum plate material, (S100) a step of forming protrusions extending from the surface of the aluminum substrate is formed; (S200) forming an anodized coating layer on the aluminum substrate in step S100; (S300) applying a subcoat layer composition on the anodized film layer, firing the subcoat layer composition, and cooling at a rate of 3 to 6 ° C / sec to form a subcoat layer; And (S400) coating and baking an upper coating layer composition containing polytetrafluoroethylene on the lower coating layer, and cooling the coating layer at a rate of 3 to 6 ° C / sec to form an upper coating layer . However, in the case of the present invention, in step S300, the undercoat layer composition is prepared by mixing 100 parts by weight of (a) polytetrafluoroethylene (PTFE), (b) tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer and And 5 to 20 parts by weight of at least one fluorocarbon copolymer selected from the group consisting of tetrafluoroethylene-hexafluoropropylene copolymer and (c) a thermally stable binder.

Hereinafter, the manufacturing method will be described separately for each process step as follows.

(S100) Formation of protrusions of aluminum substrate

First, the protrusions 11 are formed so as to extend from the surface of the aluminum substrate. In this case, the method of forming the protrusions is not particularly limited as long as it is a method of forming known in the art, but it is preferable that the protrusions 11 having the stopping jaws can be formed by the following method.

For example, the projection 11 having the latching protrusion may be formed by a process of hair-line-processing an aluminum substrate (step S110); Degreasing the aluminum substrate obtained in step S110 (step 'S120'); A zincate step (step S130) of coating the surface of the aluminum substrate obtained in step S120 with zinc; And a step of electrolytically etching the zinc-coated aluminum substrate obtained in the step S130 (step S140).

Here, the step S110 is a step of removing the oxide film formed on the surface of the aluminum substrate, and it is possible to improve the electrolytic corrosion reactivity in the electrolytic etching process step described later. In this step, sandpaper, a steel brush or the like is rubbed on the surface of the aluminum base material to form a straight line of fine lines, that is, a hair-line continuously or discontinuously.

The aluminum substrate obtained in the step S110 is dissolved in an aqueous solution of sulfuric acid (concentration: about 5 to 25%, temperature: about 60 to 80 占 폚) for about 5 to 10 minutes to degrease the aluminum substrate.

The step S130 is a zincate step of removing the oxide film formed on the surface of the aluminum substrate subjected to the step S120 so as to prevent the oxide film from being re-formed on the surface of the aluminum substrate to be treated in a later- . In this step, the aluminum substrate obtained in step S120 is added to a mixed solution of sodium hydroxide (concentration: about 10 to 100 g / l) and zinc oxide (concentration: about 5 to 50 g / And immersed for about 10 to 120 seconds to coat the surface of the aluminum substrate with zinc.

Next, in step S140, a protrusion protruding from the surface of the aluminum base material is formed on the outer surface of the aluminum base material by electrolytically etching the aluminum base material that has undergone the step S130. Specifically, a mixed solution of ammonium chloride (concentration: about 10 to 100 g / l) and a halide aqueous solution of hydrochloric acid (concentration: about 10 to 100 g / l) is contained as electrolytic solution, Prepare the electrolytic bath installed to watch. Then, by placing the aluminum substrate in the zinc-coated between two plates, and the temperature energized for about 20 ~ 60 ℃, a voltage of about 5 ~ 25 V and a current density of about 10 ~ 60 A / dm ² about 1-5 minutes When the electrolytic etching treatment is performed, the protrusions are formed on the surface of the aluminum base.

(S200) Formation of an anodic oxide coating layer

Thereafter, an anodic oxidation coating layer is formed on the aluminum substrate in step S100.

The anodic oxidation coating layer 20 is not particularly limited as long as it is a method for forming an oxidation layer of aluminum as known in the art. Preferably, the anodic oxidation coating layer 20 is chemically and physically As shown in Fig.

For example, the anodizing layer may be formed by a desmut step (step S210); And an anodizing step (&quot; S220 step &quot;).

In the step S210, the anodized film layer is a step of removing the reducing metal salt from the aluminum substrate having the protrusion 11. [ The reducing metal salt is formed by the reaction of the other metal ions in the aluminum substrate and the anion of the electrolytic solution in the electrolytic etching treatment step (step S140) for forming the protrusions. The reducing metal salt can be removed from the aluminum substrate by immersing the aluminum substrate having the protrusions 11 in an aqueous nitric acid solution (concentration: about 5 to 30%, temperature: about 10 to 35 ° C) for about 1 to 10 minutes .

In step S220, a uniform oxide film is formed on the surface of the aluminum substrate, that is, the shape of the protrusion 11, through step S210. Specifically, the aluminum substrate of the step S210 is disposed to face the anode plate in an electrolytic bath containing an aqueous sulfuric acid solution (concentration: about 5 to 25%, temperature: about 10 to 35 DEG C), and then a voltage of about 3 to 15 V is applied , And an anodic oxidation coating layer (20) is formed on the aluminum substrate.

(S300) Formation of undercoat layer

Subsequently, the undercoat layer composition is coated on the anodized film layer formed in step S200, and fired, followed by cooling to form a undercoat layer. However, as described above, the undercoat layer composition does not contain a thermally stable binder, and can be obtained by copolymerizing (a) polytetrafluoroethylene (PTFE) and (b) tetrafluoroethylene-perfluoroalkylvinylether copolymer And tetrafluoroethylene-hexafluoropropylene copolymer in a ratio of 100: 5 to 20: 1 by weight.

The method of applying the undercoating layer composition on the anodized coating layer 20 is not particularly limited, but a spin coating method or a roll coating method is preferable.

At this time, the temperature and time for firing the applied undercoat layer composition are not particularly limited, but it is preferable that the temperature is about 360 to 430 캜, and the time is about 5 to 30 minutes.

Further, it is preferable to cool the lower coating layer at a cooling rate of about 3 to 6 占 폚 / sec after baking at the above temperature and time. When the undercoat layer is cooled to the above range, the porous network structure of the polytetrafluoroethylene (PTFE) in the undercoat layer becomes denser and the pore becomes smaller, so that it is difficult to penetrate the corrosion-inducing material, And the anchoring effect between the undercoat layer and the undercoat layer is increased, so that the adhesion between the aluminum substrate and the undercoat layer can be further increased.

(S400) Formation of an upper coating layer

Then, an upper coating layer composition containing polytetrafluoroethylene is coated on the lower coating layer formed in the step S300, and fired, followed by cooling to form an upper coating layer.

The method of applying the top coat layer composition on the undercoat layer is not particularly limited, but a spin coat method or a roll coat method is preferred.

At this time, the temperature and time for baking the applied top coat layer composition are not particularly limited, but it is preferable that the temperature is about 360 to 430 캜, and the time is about 5 to 30 minutes.

Also, it is preferable that the upper coating layer formed on the lower coating layer after the firing at the above temperature and time is cooled at a rate of about 3 to 6 ° C / sec. When the upper coating layer is cooled at the cooling rate, the porous network structure of the polytetrafluoroethylene (PTFE) in the upper coating layer becomes denser and the pores become smaller, so that penetration of the corrosion-inducing material is difficult and corrosion resistance can be increased .

<Cooking container>

Meanwhile, the present invention provides a cooking vessel 200 manufactured using the aluminum plate 100 described above. The cooking container 200 is not particularly limited as long as it is used for cooking food, and includes, for example, an inner pot for an electric rice cooker, a frying pan, an electric grill, and a pot.

  The cooking vessel is manufactured by pressing the aluminum plate 100 into a container shape. As shown in FIG. 3, the cooking vessel is a main body 10 with an open upper part. The main body 10 has a protruding portion 11 extended from the surface 10); An anodic oxidation coating layer (20) formed on an outer surface of the body; A lower coating layer 30 formed on the anodized coating layer, and an upper coating layer 40 formed on the lower coating layer. Since the cooking vessel 200 is manufactured using the aluminum plate 100 described above, the use of the heat-stable bonding agent as one component of the undercoating layer is excluded as in the case of the aluminum plate. Therefore, the cooking vessel 200 is excellent in non-stickiness even when the upper coating layer is scratched or abraded by the cooking utensil or the cleaning tool to expose the undercoat layer. Further, since the cooking vessel is excellent in heat resistance, discoloration and cracking of the coating film due to thermal decomposition do not occur even if it is exposed to a high temperature for a long time. In addition, since the cooking container is excellent in corrosion resistance, it does not cause swelling and peeling of the coating film due to penetration of corrosive substances such as salt during cooking of food.

Hereinafter, the present invention will be described concretely with reference to Examples. However, the following Examples and Experimental Examples are merely illustrative of one form of the present invention, and the scope of the present invention is not limited by the following Examples and Experimental Examples .

[Example 1] - Production of aluminum sheet material

A steel brush was rubbed against the surface of an aluminum substrate (aluminum plate made of A3004 (Daikyo ALE Co., Ltd., thickness: 2.5 mm)) to form a hair-line on the aluminum base. Thereafter, the aluminum substrate on which the hairline was formed was immersed in an aqueous sulfuric acid solution (concentration: about 20%, temperature: about 70 ° C) for about 5 minutes to degrease the aluminum substrate. The degreased aluminum substrate was immersed in a mixed solution of sodium hydroxide (concentration: about 50 g / l) and zinc oxide (concentration: about 20 g / l) for about 30 seconds at a temperature of about 20 캜 for about 30 seconds, The surface was coated with zinc. Subsequently, the zinc-coated aluminum base material was placed between the positive electrode plate and the negative electrode plate in an electrolytic bath containing a mixed solution of ammonium chloride (concentration: about 50 g / l) and hydrochloric acid halide solution (concentration: about 50 g / l) , A temperature of about 30 DEG C, a voltage of about 15 V, and a current density of about 30 A / dm &lt; ² &gt; for about 3 minutes to carry out an electrolytic etching treatment to form protrusions on the surface of the aluminum base.

Next, the aluminum substrate on which the protrusions were formed was immersed in a nitric acid aqueous solution (concentration: about 20%, temperature: about 20 ° C) for about 5 minutes to remove the reducing metal salt. Thereafter, the aluminum substrate was placed so as to face the anode plate in an electrolytic bath containing an aqueous sulfuric acid solution (concentration: about 20%, temperature: about 20 ° C), and a voltage of about 9 V was applied to the anodic oxidation film layer .

Subsequently, 100 parts by weight of polytetrafluoroethylene (PTFE) and 5 parts by weight of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) were mixed to prepare a lower coating layer composition. Then, the prepared undercoat layer composition was coated on the anodized coating layer by spin coating, baked at a temperature of about 380 ° C for about 10 minutes, and then cooled at a rate of about 5 ° C / sec to form a undercoat layer 25 탆).

Finally, 100 parts by weight of a top coat layer composition (polytetrafluoroethylene (PTFE)) is applied on the undercoat layer by spin coating, baked at a temperature of about 380 DEG C for about 10 minutes, sec to form an upper coating layer (thickness: about 15 mu m) to prepare an aluminum plate material.

[Examples 2 to 3] and [Comparative Examples 1 to 10]

An aluminum plate was produced in the same manner as in Example 1 except that the composition and content of the undercoat layer composition were changed according to the composition shown in Table 1 below. In the following Table 1, PAI is a polyamide-imide (including repeating units of Formula 1), a type of thermostable binder, and the amount of each composition used is in parts by weight.

Undercoat layer composition Top coat layer composition PTFE PFA PAI PTFE Example 1 100 5.0 - 100 Example 2 100 10.0 - 100 Example 3 100 20.0 - 100 Comparative Example 1 100 - - 100 Comparative Example 2 100 3.0 - 100 Comparative Example 3 100 30.0 - 100 Comparative Example 4 100 50.0 - 100 Comparative Example 5 100 5.0 1.0 100 Comparative Example 6 100 10.0 1.0 100 Comparative Example 7 100 10.0 5.0 100 Comparative Example 8 100 10.0 10.0 100 Comparative Example 9 100 20.0 1.0 100 Comparative Example 10 - 100 1.0 100

[Experimental Example 1] - Appearance evaluation

The surface of the aluminum plate prepared in Examples 1 to 3 and Comparative Examples 1 to 10 was observed with a naked eye and an optical microscope to confirm whether coating layer defects such as cracks, pinholes, cracks, smoothness and yellowing occurred. Observation results are shown in Table 2 below.

[Experimental Example 2] - Adhesion test

A tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer film (thickness: 100 占 퐉) was heat-fused to the surfaces of the aluminum plates prepared in Examples 1 to 3 and Comparative Examples 1 to 10, and then this was fused with a vapor pressure tester AUTO CLAVE , A vapor pressure was applied at a temperature of 150 ° C and a gauge pressure of 4 atm for 100 hours, and then the adhesive force was measured by a 90 degree peeling tester. The measurement results are shown in Table 2 below.

[Experimental Example 3] - Salt water boiling test

The aluminum sheets prepared in Examples 1 to 3 and Comparative Examples 1 to 10 were immersed in a 5% NaCl aqueous solution at a temperature of 96 캜 for 10 hours. This process was repeated to measure the time until coating film defects such as swelling, corrosion, peeling, etc. occurred in the coating layer. The measurement results are shown in Table 2 below.

[Experimental Example 4] - Heat resistance test

The aluminum plate materials prepared in Examples 1 to 3 and Comparative Examples 1 to 10 were placed in an oven and left at a temperature of 350 DEG C for 10 hours. This process was repeated to measure the time until coating film defects such as coating cracks and gambling whitening occurred on the coating layer. The measurement results are shown in Table 2 below.

[Experimental Example 5] - Non-stick test

The aluminum plate materials produced in Examples 1 to 3 and Comparative Examples 1 to 10 were pressed into a container shape to prepare a cooking container. After a cooking vessel was fixed to a wringing abrasion tester, a Scotch-brite # 7447 wringing pad (5 cm x 5 cm) was placed in the center of the cooking vessel with a 0.5% neutral detergent solution poured into the cooking vessel, 12.5 m / min, and stroke length of 7 cm, the upper coating layer was worn by 1000 reciprocating movements while replacing the scrubbing pad every 250 times so that the undercoat layer was exposed. Thereafter, the cooking vessel was heated so that the surface temperature of the cooking vessel became 190 to 210 DEG C, and then the egg fry was cooked for 2 minutes in the absence of oil. The cooking process was repeated to measure the number of times that the egg fryer could be cooked without being stuck on the coating layer. The measurement results are shown in Table 2 below.

Exterior Adhesion
(gf / 5 mm) Salt water boiling (hr) Heat resistance
(hr) Non-sticky
(time) Example 1 Good 720 280 120 119 Example 2 Good 780 310 120 124 Example 3 Good 740 300 110 117 Comparative Example 1 Good 410 120 110 105 Comparative Example 2 Good 450 150 120 114 Comparative Example 3 Lack of smoothness
Coating cracking occurred 370 90 110 118 Comparative Example 4 Lack of smoothness
Coating cracking occurred 320 70 110 121 Comparative Example 5 Good 730 40 40 27 Comparative Example 6 Good 770 40 40 29 Comparative Example 7 Yellow 790 30 30 21 Comparative Example 8 Yellow 760 25 10 14 Comparative Example 9 Good 740 40 40 30 Comparative Example 10 Lack of smoothness
Coating cracking occurred 650 60 40 27

From the above Table 2, unlike the aluminum plate materials of Comparative Examples 1 to 10, the aluminum plate materials of Examples 1 to 3 exhibited no coating film defects in appearance, and were excellent in terms of adhesive strength, corrosion resistance, heat resistance and non-stickiness. In particular, the aluminum plate materials of Examples 1 to 3 exhibited similar adhesive strength to the aluminum plate materials of Comparative Examples 5 to 10 using PAI as components of the undercoat layer composition, and had corrosion resistance, heat resistance and non-stickiness Was better.

[Examples 4 to 6] and [Comparative Examples 11 to 19]

An aluminum plate was produced in the same manner as in Example 1 except that the composition and content of the undercoat layer composition were changed according to the composition shown in Table 3 below. In the following Table 3, FEP is a tetrafluoroethylene-hexafluoropropylene copolymer, PAI is the same as the polyamide-imide in Table 1, and the amount of each composition used is in parts by weight.

Undercoat layer composition Top coat layer composition PTFE FEP PAI PTFE Example 4 100 5.0 - 100 Example 5 100 10.0 - 100 Example 6 100 20.0 - 100 Comparative Example 11 100 3.0 - 100 Comparative Example 12 100 30.0 - 100 Comparative Example 13 100 50.0 - 100 Comparative Example 14 100 5.0 1.0 100 Comparative Example 15 100 10.0 1.0 100 Comparative Example 16 100 10.0 5.0 100 Comparative Example 17 100 10.0 10.0 100 Comparative Example 18 100 20.0 1.0 100 Comparative Example 19 - 100 1.0 100

[Experimental Example 6] - [Experimental Example 10]

The appearance, adhesion, corrosion resistance, heat resistance and non-stickiness of the aluminum plates of Examples 4 to 6 and Comparative Examples 11 to 19 were evaluated according to Experimental Examples 1 to 5 above. The evaluation results are shown in Table 4 below.

Exterior Adhesion
(gf / 5 mm) Salt water boiling
(hr) Heat resistance
(hr) Non-sticky
(time) Example 4 Good 700 250 100 112 Example 5 Good 770 290 120 119 Example 6 Good 720 290 100 116 Comparative Example 11 Good 410 150 110 112 Comparative Example 12 Lack of smoothness
Coating cracking occurred 370 70 110 115 Comparative Example 13 Lack of smoothness
Coating cracking occurred 330 80 100 120 Comparative Example 14 Good 710 40 40 25 Comparative Example 15 Good 740 40 40 30 Comparative Example 16 Yellow 770 30 30 22 Comparative Example 17 Yellow 770 30 10 12 Comparative Example 18 Good 720 30 30 28 Comparative Example 19 Lack of smoothness
Coating cracking occurred 630 30 40 24

It can be seen from Table 4 that the aluminum plate materials of Examples 4 to 6 had no coating film defects apparently, unlike the aluminum plate materials of Comparative Examples 11 to 19, and were superior in overall adhesion, corrosion resistance, heat resistance and non-stickiness. In particular, the aluminum plate materials of Examples 4 to 6 exhibited similar adhesive strength to the aluminum plate materials of Comparative Examples 14 to 19 using PAI as components of the undercoat layer composition, and were superior in corrosion resistance, heat resistance and non-stickiness to aluminum plates of Comparative Examples 14 to 19 .

[Examples 7 to 11] and [Comparative Examples 20 to 28]

An aluminum plate was produced in the same manner as in Example 1 except that the composition and content of the undercoat layer composition were changed according to the composition shown in Table 5 below. In the following Table 5, FEP is a tetrafluoroethylene-hexafluoropropylene copolymer, PAI is the same as the polyamide-imide in Table 1, and the amount of each composition used is in parts by weight.

Undercoat layer composition Top coat layer composition PTFE PFA FEP PAI PTFE Example 7 100 2.5 2.5 - 100 Example 8 100 5.0 5.0 - 100 Example 9 100 10.0 10.0 - 100 Example 10 100 2.5 7.5 - 100 Example 11 100 7.5 2.5 - 100 Comparative Example 20 100 1.5 1.5 - 100 Comparative Example 21 100 15.0 15.0 - 100 Comparative Example 22 100 25.0 25.0 - 100 Comparative Example 23 100 2.5 2.5 1.0 100 Comparative Example 24 100 5.0 5.0 1.0 100 Comparative Example 25 100 10.0 10.0 1.0 100 Comparative Example 26 100 2.5 7.5 1.0 100 Comparative Example 27 100 7.5 2.5 1.0 100 Comparative Example 28 - 50.0 50.0 1.0 100

[Experimental Example 11] - [Experimental Example 15]

The appearance, adhesion, corrosion resistance, heat resistance and non-stickiness of the aluminum plates of Examples 7 to 11 and Comparative Examples 20 to 28 were evaluated according to Experimental Examples 1 to 5 above. The evaluation results are shown in Table 6 below.

Exterior Adhesion
(gf / 5 mm) Salt water boiling
(hr) Heat resistance (hr) Non-stickiness (times) Example 7 Good 720 280 120 119 Example 8 Good 780 310 120 124 Example 9 Good 740 300 110 117 Example 10 Good 750 300 110 119 Example 11 Good 770 320 120 122 Comparative Example 20 Good 400 150 110 112 Comparative Example 21 Lack of smoothness
Coating cracking occurred 360 60 100 115 Comparative Example 22 Lack of smoothness
Coating cracking occurred 340 70 100 120 Comparative Example 23 Good 700 30 40 25 Comparative Example 24 Good 720 40 40 30 Comparative Example 25 Good 750 40 30 22 Comparative Example 26 Good 720 30 10 12 Comparative Example 27 Good 760 40 30 28 Comparative Example 28 Lack of smoothness
Coating cracking occurred 660 40 40 25

As can be seen from Table 6, unlike the aluminum plate materials of Comparative Examples 20 to 28, the aluminum plate materials of Examples 7 to 11 exhibited no coating film defects on the outside and were excellent in terms of adhesive strength, corrosion resistance, heat resistance and non-stickiness. In particular, the aluminum plate materials of Examples 7 to 11 exhibited similar adhesive strength to the aluminum plate materials of Comparative Examples 23 to 28 using PAI as components of the undercoat layer composition, and had corrosion resistance, heat resistance and non-stickiness .

10: Aluminum base material
11: protrusion,
11a: width direction of the projection,
20: anodic oxidation coating layer,
30: undercoat layer,
31: inorganic filler for coating film reinforcement,
40: top coating layer,
100: Aluminum plate,
200: Cooking container

Claims (9)

An aluminum base having protrusions protruding from the surface;
An anodic oxidation coating layer formed on the aluminum substrate;
A lower coating layer formed on the anodized coating layer; And
And an upper coating layer formed on the lower coating layer,
The undercoat layer comprises (a) 100 parts by weight of polytetrafluoroethylene (PTFE), (b) a mixture of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer and tetrafluoroethylene-hexafluoropropylene copolymer (C) 5 to 20 parts by weight of at least one selected from the group consisting of a fluorocarbon compound and a fluorocarbon compound,
Wherein the protruding portion includes a section in which the length in the width direction increases as the cross-sectional shape is further away from the aluminum base material, and the surface roughness is 1 to 5 占 퐉. The method according to claim 1,
Wherein the undercoat layer composition comprises an inorganic filler for coating film reinforcement, a flake-like filler, or both. 3. The method of claim 2,
Wherein the contents of the inorganic filler for coating film and the flake-like filler are each 1 to 10 parts by weight based on 100 parts by weight of the polytetrafluoroethylene. delete The method according to claim 1,
Wherein the top coat layer is formed of a top coat layer composition comprising polytetrafluoroethylene (PTFE). (S100) forming a projection on the aluminum substrate, the projection extending from the surface;
(S200) forming an anodized coating layer on the aluminum substrate in step S100;
(S300) applying a subcoat layer composition on the anodized film layer, firing the subcoat layer composition, and cooling at a rate of 3 to 6 ° C / sec to form a subcoat layer; And
(S400) applying and coating a top coat layer composition comprising polytetrafluoroethylene on the undercoat layer, cooling at a rate of 3 to 6 ° C / sec to form an overcoat layer
Lt; / RTI &gt;
In operation S100,
(S110) hair-line processing the aluminum substrate;
(S120) a step of immersing the aluminum substrate obtained in the step S110 in an aqueous sulfuric acid solution (concentration: 5 to 25%, temperature: 60 to 80 ° C) for 5 to 10 minutes to degrease the aluminum substrate;
(S130) The aluminum substrate obtained in the step S120 is immersed in a mixed solution of sodium hydroxide (concentration: 10 to 100 g / l) and zinc oxide (concentration: 5 to 50 g / Zincate for 120 seconds to coat the surface of the aluminum substrate with zinc; And
(S140) The zinc-coated aluminum substrate obtained in the step S130 is immersed in a mixed solution of ammonium chloride (concentration: 10 to 100 g / l) and hydrochloric acid halide solution (concentration: 10 to 100 g / Electrolytic etching treatment for 1 to 5 minutes at a temperature of 20 to 60 캜, a voltage of 5 to 25 V, and a current density of 10 to 60 A / dm ²
The method of manufacturing an aluminum plate material according to any one of claims 1 to 3, delete The method according to claim 6,
In operation S200,
(S210) The aluminum substrate obtained in the step S100 is immersed in an aqueous nitric acid solution (concentration: 5 to 30%, temperature: 10 to 35 ° C) for 1 to 10 minutes to remove the reducing metal salt from the aluminum substrate, ) step; And
(S220) The aluminum substrate of step S210 is subjected to a voltage of 3 to 15 V in an aqueous sulfuric acid solution (concentration: 5 to 25%, temperature: 10 to 35 ° C) to form an oxide film on the surface of the aluminum substrate Steps to Anodize
Wherein the aluminum foil is made of aluminum. A cooking container produced by pressing the aluminum plate according to any one of claims 1 to 3 into a container shape.

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