KR101689634B1 - Surface Coating Method Exhibiting Solid Pattern Texture - Google Patents

Abstract

The present invention relates to a surface-coating method for creating three-dimensional textures, by sequentially carrying out a primer coating process, a mid coating process, and a top coating process on surfaces of objects such as kitchen utensils, using a fluorine resin coating composition. According to the present invention, the coating method enables formation of various colors and three-dimensional textures on the surface of the kitchen utensils with a simple process, while ensuring corrosion resistance and wear resistance. In addition, the coating method also allows coating films to keep original coating properties even after a long period of use, since the coating films are strongly bonded to the surface of the kitchen utensils and thus are not easily exfoliated. Owing to outstanding release properties, it is possible to prevent foods from sticking on the coating films during cooking.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface coating method,

The present invention relates to a surface coating method which displays a three-dimensional pattern texture by sequentially performing a primer coating, a mid coating and a top coating on a surface of a kitchen appliance or the like .

In general, a kitchen appliance is a device for cooking food such as a frying pan, a pot, etc., and it cuts or grinds the rough surface, prevents the food from sticking, and also performs coating treatment to prevent phenomena such as scratches due to external contact.

The coating treatment may be carried out by a method such as undercoating, intermediate coating and top coating, and may be carried out using a fluororesin coating, a ceramic coating, a Teflon coating, a titanium coating, or the like. Typically, A method of coating a fluororesin coating material typified by polytetrafluoroethylene (PTFE) is widely used.

The fluororesin has been widely used as a coating material for kitchen utensils because of its excellent non-tackiness and chemical resistance. As a method of coating a fluororesin on a metal base material of a kitchen appliance, a method of blasting, A surface roughing treatment is carried out on the surface of the base material, and the base material is first firmly adhered to the surface of the base material, and a fluororesin is bonded to the undercoating material or fine irregularities are formed on the surface of the base material. A method of physically bonding a fluororesin is used.

In addition, methods such as undercoating, intermediate coating and topcoating are commonly used on the surface of the apparatus. As such a coating method, there is a method of coating a middle coat with a low viscosity black, silver or various colors after undercoating, The pattern is made by using the spray paint of the intermediate paint and then the top paint is coated to express the various colors to create the pattern on the surface.

However, when the conventional coating is applied by the above-mentioned conventional coating, a three-dimensional pattern is not formed on the surface of the container, and a planar coating is formed. When the coating is applied several times to give irregularities to the coated film, the surface becomes rough and cracks easily occur, This is a weak point.

In addition, conventional fluororesin paints are screen-printed after undercoating, topcoat or various colors are put on the intermediate paint to form various irregularities on the surface by coating each color several times in order to express various colors or patterns. In this case There is a disadvantage in that it is difficult to control the thickness of the coating film because the drying film is rough and the work process is long and many spray guns are required.

Conventional methods other than the above have a long working process, so that the loss of the paint during operation is large, and it is impossible to make a uniform three-dimensional pattern or to smooth the surface of the irregular coating film.

To solve this problem, Korean Utility Model Appln. Utility Model No. 20-0347043 discloses a method of forming an original coating layer by applying a ceramic paint, a heat-resistant paint or a fluorine resin paint on the surface of a tool, and applying an ink pigment thereon in a spot- Discloses an invention in which a discontinuous coating layer of unevenness is formed on the surface.

According to the above publication, the discontinuous coating layer of the ink pigment applied in the spot-like form protrudes toward the upper part, so that the scratch phenomenon does not occur, the surface area of the food by the protrusion is increased relatively and the heat is transferred uniformly, The effect that the effect is exerted can be obtained.

However, since the ink pigment applied in the spot-like form is discontinuously bound to the original coating layer, the binding force between the ink pigment and the original coating layer is insufficient, and when the ink pigment is separated from the original coating layer, It is difficult to form various patterns, and it is difficult to express the three-dimensional pattern in particular.

Korean Patent Registration No. 10-1382576 discloses a method of forming a three-dimensional pattern on the bottom of a kitchen container using an electromagnet module and a magnetic coating agent. In this method, a magnetic coating agent is applied to the bottom of a kitchen container, The magnetic coating agent is agglomerated in a specific pattern by selectively applying a power source to form a magnetic field. The magnetic coating agent is allowed to stand for a predetermined time and then fired to form a three-dimensional pattern on the bottom of the kitchen container.

The above method has the advantage of easily and precisely forming the three-dimensional pattern and controlling the shape and thickness and shortening the processing time. However, since the coating agent binds to the bottom surface of the kitchen container by firing, And the magnetic body is coated by firing, so that the surface is rough and cracks are easily generated, which is disadvantageous in that wear resistance and corrosion resistance are weak.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method for manufacturing a food product, which is capable of forming a solid pattern on a surface of a heating device such as a kitchen appliance, And a surface coating method which exhibits a three-dimensional pattern texture so as not to stick to the surface.

In order to solve the above problems, the present invention provides a process for producing a polytetrafluoroethylene paste, which comprises mixing 10 to 20 parts by weight of N-methyl-2-pyrrolidone and 70 to 85 parts by weight of water in 100 parts by weight of polytetrafluoroethylene paste (solid content 50 to 60% , 80 to 100 parts by weight of a polyether sulfone paste (solid content 13 to 30% by weight), 80 to 100 parts by weight of a polyamideimide paste (solid content 13 to 30% by weight) 10 to 20 parts by weight of silica sol (solid content 25 to 35% by weight) and 5 to 10 parts by weight of diacetone alcohol were mixed to prepare a undercoating composition ; Coating the undercoating composition on the surface of a kitchen utensil at a pressure of 100-500 ㎪ and drying at 50-280 캜 for 5-30 minutes to form a undercoat layer; 10 to 20 parts by weight of a water-soluble acrylic resin, 25 to 35 parts by weight of water, 1 to 5 parts by weight of dimethylaminoethanol, 0.5 to 5.0 parts by weight of pearl pigment, 100 parts by weight of a pearl pigment, 20 to 30 parts by weight of perfluoroalkoxy resin (solid content 20 to 50% by weight), 5 to 15 parts by weight of an acrylic dispersant, 2 to 6 parts by weight of a dispersant, 4 to 7 parts by weight of a thickener, ethylene glycol monobutyl ether 4 To 8 parts by weight of an inorganic pigment and 2 to 5 parts by weight of an inorganic pigment to prepare an intermediate coating composition; Coating the dried coating composition on the dried coating composition at a pressure of 10 to 300; to form a coating layer; 7 to 13 parts by weight of a water-soluble acrylic resin, 30 to 50 parts by weight of water, 1 to 5 parts by weight of dimethylaminoethanol, and 0.05 to 0.5 parts by weight of pearl pigment in 100 parts by weight of a polytetrafluoroethylene paste (solid content 50 to 60% by weight) 25 to 35 parts by weight of perfluoroalkoxy resin (solid content 20 to 50% by weight). 2 to 6 parts by weight of triethanolamine and 5 to 10 parts by weight of a dispersant to prepare an upper coating composition; And coating the top coating composition on the middle coating layer with a wet-on-wet method at a pressure of 100 to 500 방식 and drying the coating composition at 350 to 450 캜 for 5 to 50 minutes to form an upper coating layer. A surface coating method is provided.

The coating method according to the present invention is capable of expressing various colors and three-dimensional pattern texture on the surface of a kitchen utensil by a simple work process, and is excellent in corrosion resistance and abrasion resistance, and since the coating film is firmly adhered to the surface of a kitchen utensil, And the releasing property is excellent, so that the food does not adhere to the coating film during the food cooking process.

1 is a cross-sectional view showing a coating film coated with the method of the present invention showing a three-dimensional pattern texture.
FIG. 2 is a theoretical illustration of a coating layer coated with the method of the present invention, which shows a virtual three-dimensional pattern texture.
Figure 3 is a partial enlarged view showing the texture of the kitchen utensil coated with the method of the present invention.

The present invention comprises a process for preparing a subcoating, a middle coating and an uppercoating composition comprising polytetrafluoroethylene as a main component and coating the same on a kitchen appliance in order to display various three-dimensional pattern textures on the surface of a kitchen appliance.

Specifically, it is coated with a low-viscosity composition having excellent adhesion to the surface of a kitchen utensil and an intermediate coating layer, dried and then coated with a high-viscosity composition exhibiting a three-dimensional pattern texture on the undercoat layer. Coating a composition having a low viscosity with a non-stick coating on the surface of the coating in a wet-on-wet manner with the intermediate coating layer, and the coating film exhibits excellent corrosion resistance and abrasion resistance, And it is excellent in releasing property, so that the food does not stick to the surface of the kitchen utensil during cooking.

First, a subcoat composition for forming a subcoat layer is prepared.

The undercoating composition is prepared by mixing 10 parts by weight of N-methyl-2-pyrrolidone (NMP) solvent in 100 parts by weight of polytetrafluoroethylene paste (solid content 50 to 60% by weight) 20 to 30 parts by weight of a polyether sulfone (PES) paste (solid content 13 to 30% by weight) (Al ₂ O ₃ ) 25 to 35 parts by weight, silicon carbide (SiC) 10 to 20 parts by weight (PAI) paste (solid content 13 to 30% by weight), 1 to 5 parts by weight of an inorganic pigment, 10-20 parts by weight of silica sol (solid content 25-35% by weight) and 5-10 parts by weight of 4-hydroxy-4-methyl-2-pentanone (DAA) solvent.

The undercoating is applied at a pressure of 100 ~ 500 이용 using a general spray on the surface of the kitchen utensil, dried at 50 ~ 280 캜 for 5 ~ 30 minutes after the undercoating, and the dry coating thickness of the undercoating layer formed by undercoating is 10 To 100 [mu] m.

The intermediate coating composition comprises 10 to 20 parts by weight of a water-soluble acrylic resin, 25 to 35 parts by weight of pure water, 100 parts by weight of dimethylaminoethanol (hereinafter, referred to as " water-soluble acrylic resin " 1 to 5 parts by weight of dimethylaminoethanol (DMAE), 0.5 to 5.0 parts by weight of a pearl pigment, 20 to 30 parts by weight of a perfluoroalkoxy (PFA) resin (solid content 20 to 50% by weight) 5 to 15 parts by weight of a dispersant, 2 to 6 parts by weight of a dispersant, 4 to 7 parts by weight of a thickener, 4 to 8 parts by weight of ethylene glycol monobutyl ether (EGBE) and 2 to 5 parts by weight of an inorganic pigment.

Preferably, the intermediate coating is applied to the dried undercoat layer at a pressure of 10 to 300 이용 using low-pressure spraying, and the thickness of the intermediate coating layer formed by the intermediate coating is in the range of 30 to 300 탆.

The top coat composition is prepared by mixing 7 to 13 parts by weight of a water-soluble acrylic resin, 30 to 50 parts by weight of pure water, 1 to 5 parts by weight of dimethylaminoethanol with 100 parts by weight of a polytetrafluoroethylene paste (solid content 50 to 60% by weight) 0.05 to 0.50 parts by weight of pearl pigment, and 25 to 35 parts by weight of perfluoroalkoxy resin (solid content 20 to 50% by weight). 2-6 parts by weight of triethanolamine (TEA) and 5-10 parts by weight of a dispersant.

The top coat is applied by wet-on-wet method at a pressure of 100 to 500 일반 using a common spray on the middle coat layer, then dried at 350 to 450 캜 for 5 to 50 minutes, and the dry coat thickness of the top coat layer formed by the top coat is And preferably in the range of 10 to 100 mu m.

When the final drying temperature is less than 380 ° C or the drying time is less than 5 minutes, adhesion and binding force between the surface of the kitchen utensil and the undercoating layer and each coating layer is low, and the drying force is low When the temperature exceeds 450 ° C or the drying time exceeds 50 minutes, there is a problem that the corrosion resistance, abrasion resistance and releasability of the coating film are lowered and the dimensional sensation of the pattern formed on the surface of the kitchen appliance is lowered.

The viscosity of each coating composition is controlled depending on the content of the solvent used in the above-mentioned undercoating composition and the pure water used in the pure water, the intermediate coat and the top coat composition. The undercoat and top coat compositions have a high content ratio of solvent and pure water To keep the viscosity low and the intermediate coating composition keeps the content of pure water low to keep the viscosity high.

Accordingly, a low-viscosity undercoating composition is sprayed at high pressure onto the surface of a kitchen utensil, spreading uniformly while forming a subcoat layer, and forming a midcoat layer by intermittently laminating a heavy- The top coat coating composition is sprayed at high pressure to form a coating film.

As described above, due to the viscosity control of each coating composition, the undercoat layer binds to the surface of the kitchen utensil, and the intermediate coating layer is firmly adhered to the surface of the kitchen utensil through the undercoat layer. The coating layer of the coating film exhibits a three-dimensional pattern texture, and the top coating layer is coated with the middle coating layer and the wet-on-wet coating method so as to firmly bind to the top coating layer.

1 to 3 show the appearance of a coating film coated on the surface of a kitchen utensil according to the present invention. Referring to Fig. 1, a subcoat layer 2 is formed on a substrate layer 1 of a kitchen appliance, The intermediate coating layer 3 is formed on the upper coating layer 2 and the intermediate coating layer 3 is sprayed with a high viscosity intermediate coating composition at a low pressure so that the composition is laminated as shown in FIG. The upper coating layer 4 is formed on the upper surface of the upper coating layer 4 so that the surface of the upper coating layer 4 is formed as the concave-convex shape of the upper surface of the middle coating layer 3. As a result, .

When the food is cooked in the coated coating film having irregularities as described above, moisture of the food is removed by cooking heat, and the food is shrunk to contact the food only on the protrusion of the coated film. As a result, the food is not easily Fall off.

The viscosity of the undercoat composition and the top coat composition is preferably low, which takes 8 to 15 seconds to be discharged from the Jahm Cup # 3, and it is preferable that the intermediate coating composition has a high viscosity of 50,000 to 100,000 centipoise (cP) .

The polytetrafluoroethylene resin used as a main material of the coating composition used in the present invention is excellent in chemical resistance, stable at high temperature, and excellent in releasability, and is widely used as a coating material for kitchen appliances.

The polyether sulfone resin and the polyamideimide resin used in the undercoating composition serve to improve abrasion resistance at a high temperature and to enhance the thermal stability of the polytetrafluoroethylene resin. The polyether sulfone resin is an amorphous, aromatic resin The polyamide-imide resin is excellent in heat resistance, abrasion resistance, mechanical, chemical, and electrical properties. When the content of each component is less than 80 parts by weight, the polyamide-imide resin is excellent in heat resistance, heat resistance, resistance to steam, flame retardancy, And peeling of the coating film occurs. When the amount exceeds 100 parts by weight, the viscosity of the undercoat composition becomes too high, and the undercoat layer is not thin and has a certain thickness.

The N-methyl-2-pyrrolidone used in the undercoat composition is a polar organic solvent that liquefies polytetrafluoroethylene, polyether sulfone and polyamideimide resin and controls the viscosity of the undercoat composition, Silicon carbide and silica sol serve to enhance the function of the coating film by imparting hardness, impact resistance, abrasion resistance, heat resistance, stain resistance, flame resistance and corrosion resistance to the coating film.

The diacetone alcohol used in the undercoating composition enhances the pigment dispersibility in the composition and smoothes the surface of the coating film and prevents the pinhole phenomenon during spray coating.

Examples of the inorganic pigments used in the undercoating and intermediate coating compositions include transition metal oxide based inorganic pigments or graphite such as titanium oxide, zinc oxide, magnesium oxide, zirconium oxide, iron oxide, cobalt oxide and chromium oxide, carbon nanotubes, Carbon black and the like may be used, and mica-titanium oxide pearl pigments may be used as pearl pigments used in the intermediate coating and top coat composition, but the present invention is not limited thereto.

Examples of the water-soluble acrylic resin to be used in the above-mentioned intermediate coating and top coat coating composition include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) (Meth) acrylate, 2-ethylhexyl (meth) acrylate, hydroxypropyl (meth) acrylate, stearyl (meth) acrylate and hydroxybutyl But is not limited thereto.

The weight average molecular weight of the water-soluble acrylic resin is preferably 10,000 to 25,000. If the molecular weight is less than 10,000, the workability may be deteriorated. If the weight-average molecular weight is more than 25,000, the stability of the composition decreases and the viscosity becomes too high.

The acrylic dispersant used in the intermediate coating composition is preferably a (meth) acrylic acid ester non-volatile water-soluble polymer dispersant, which induces dispersion of the water-soluble acrylic resin in the composition. The (meth) acrylic ester- Flexibility, alkali resistance and weather resistance, which is effective not only for dispersing the water-soluble acrylic resin but also for improving the physical properties of the coating film.

The ethylene glycol monobutyl ether used in the above-mentioned heavy-weight coating composition is used to prevent the coating film from cracking due to the slow drying of the coating film in the drying furnace after spray coating.

The perfluoroalkoxy resin used in the intermediate coating and top coat coating composition has excellent heat stability and excellent releasability to provide a function of preventing the food from adhering to the coating film. Dimethylaminoethanol improves the storage stability of the coating material and has a constant viscosity And the triethanolamine used in the top coat composition is used as a catalyst to maintain a constant viscosity of the coating.

It is preferable that the dispersant used in the undercoat, intermediate coat, and top coat composition is a nonionic surfactant, and the nonionic surfactant is not ionic in an aqueous solution state, and does not affect other components in the composition, And emulsification performance.

As such a dispersing agent, polyoxyethylene nonylphenyl ether is preferable, and polyoxyethylene nonylphenyl ether is excellent in solubilization ability to induce even dispersion of the composition and to form a film by drying, so that the corrosion resistance, Water resistance, stain resistance, and releasability.

The material of the kitchen utensil to which the coating method of the present invention can be applied is not limited to the kinds of materials such as aluminum, aluminum alloy, steel, stainless steel, and ceramics.

Hereinafter, the present invention will be described in more detail with reference to the following examples and test examples.

It is to be understood, however, that the invention is not to be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Will be apparent to those skilled in the art to which the present invention pertains.

≪ Example 1 > Preparation of undercoat composition

(PAI) paste having a solid content of 25% by weight and a polyether sulfone (PES) having a solid content of 20% by weight. The composition of the undercoating composition is as follows: ) Paste were mixed, and while stirring at high speed, 136 g of N-methyl-2-pyrrolidone (NMP) solvent, 545 g of pure water and 68 g of diacetone alcohol (DAA) solvent were sequentially mixed and stirred for 20 minutes Respectively.

After thoroughly stirring, 23 g of black inorganic pigment, 295 g of aluminum oxide powder, 159 g of silicon carbide powder and 136 g of dispersant were added and sufficiently stirred at high speed. 136 g of a silica sol solution having a solid content of 30% 227 g of pure water and 1 kg of a polytetrafluoroethylene (PTFE) paste having a solid content of 55% by weight were further added and stirred.

The contents are thoroughly mixed and agitated and then filtered through a 300 mesh filter. If necessary, pure water may be added to adjust the viscosity of the undercoat composition (A1-type).

The B1-type to E1-type undercoat compositions were prepared as described above, and the composition ratios of the respective components are shown in Table 1 below.

Preparation of Subcoat Composition Composition ratio ingredient Content (g) / Component ratio (% by weight) Remarks A1-type B1-type C1-type D1-type E1-type 25 wt% PAI 909/20 1136/25 682/15 1176/20 469/15 water based 20 wt% PES 909/20 682/15 1136/25 1176/20 469/15 water based NMP 136/3 136/3 136/3 176/3 94/3 Pure water 545/12 545/12 545/12 706/12 375/12 DAA 68 / 1.5 68 / 1.5 68 / 1.5 88 / 1.5 47 / 1.5 Black inorganic pigment 23 / 0.5 23 / 0.5 23 / 0.5 29 / 0.5 16 / 0.5 Degussa special black F80 Aluminum oxide 295 / 6.5 295 / 6.5 295 / 6.5 382 / 6.5 203 / 6.5 Alodur WSK3000 Silicon carbide 159 / 3.5 159 / 3.5 159 / 3.5 206 / 3.5 109 / 3.5 F1200, ESC-SIS-GmbH Dispersant 136/3 136/3 136/3 176/3 94/3 Triton X-100, Dow Chemical 30 wt% silica sol 136/3 136/3 136/3 176/3 94/3 Levasil
200A / 30%, Akzo-Nobel Pure water 227/5 227/5 227/5 588/10 156/5 55 wt% PTFE 1000/22 1000/22 1000/22 1000/17 1000/32 Inoflon AD9200TP, Gujarat Fluorochemicals Limited Sum 4543/100 4543/100 4543/100 5879/100 3126/100

When the undercoating composition prepared as shown in Table 1 was coated on a kitchen appliance, the A1-type composition had excellent adhesion to the coating layer and corrosion resistance, but the B1-type and C1-type compositions had good adhesion to the intermediate coating layer, And when the composition ratio of polytetrafluoroethylene is changed as in the case of the D1-type and E1-type compositions, there is a problem in durability due to poor adhesion to the intermediate coating layer, and the A-type composition exhibits the most excellent properties .

≪ Example 2 > Preparation of intermediate coating composition

First, 144 g of a water-soluble acrylic resin, 154 g of pure water, and 32 g of dimethylaminoethanol (DMAE) were mixed and stirred to form a pearl pigment , 1 kg of a polytetrafluoroethylene (PTFE) paste having a solid content of 55% by weight, and 220 g of a perfluoroalkoxy (PFA) resin having a solid content of 35% by weight.

After sufficiently stirring, 100 g of an acrylic dispersant, 40 g of a dispersant, 60 g of ethylene glycol monobutyl ether (EGBE) and 40 g of a black inorganic pigment were added and thoroughly stirred. Then, the mixture was filtered through a 300-mesh filter medium to obtain a butylcellulose thickener 60 g were added and stirred until thoroughly mixed, then 140 g of pure water was added to adjust the viscosity of the undercoating composition (A2-type).

B2-type or E2-type intermediate coating compositions were prepared in the same manner as described above. Composition ratios of the respective components are shown in Table 2 below.

Preparation of Modified Coating Composition Composition ratio ingredient Content (g) / Component ratio (% by weight) Remarks A2-type B2-type C2-type D2-type E2-type Water-soluble acrylic resin 144 / 7.2 200/10 98 / 4.9 144 / 7.2 144 / 7.2 Weight average molecular weight 10000 to 25000 Pure water 154 / 7.7 98 / 4.9 200/10 154 / 7.7 154 / 7.7 DMAE 32 / 1.6 32 / 1.6 32 / 1.6 32 / 1.6 32 / 1.6 Elementis-Deuchem Pearl pigment 10 / 0.5 10 / 0.5 10 / 0.5 10 / 0.5 10 / 0.5 IRIODIN, Merck 55 wt% PTFE 1000/50 1000/50 1000/50 1000/50 1000/50 PTFE Dispersion D310, Daikin  35 wt% PFA 220/11 220/11 220/11 220/11 220/11 Dupon Acrylic dispersant 100/5 100/5 100/5 100/5 100/5 LDM7991, Celanese  Dispersant 40/2 40/2 40/2 40/2 40/2 Triton X-100, Dow Chemical EGBE 60/3 60/3 60/3 60/3 60/3 Dow Chemical Black inorganic pigment 40/2 40/2 40/2 40/2 40/2 Thickener 60/3 40/2 20/1 80/4 100/5 Butyl cellulose system, Shanghai Rongou Chemical Pure water 140/7 160/8 180/9 120/6 100/5 Sum 2000/100 2000/100 2000/100 2000/100 2000/100

When the intermediate coating composition prepared as shown in Table 2 was coated on a sufficiently dried undercoat layer, the B2-type and C2-type compositions were thin in viscosity and formed a flat surface during coating, The D2-type and E2-type compositions have very high viscosity, and the three-dimensional pattern is well formed on the surface during coating, but the coating is cracked, resulting in poor abrasion resistance and corrosion resistance. Especially, high viscosity causes clogging of spray gun Respectively.

In the case of the A2-type composition, the above-mentioned problems did not occur and the adhesive strength to the undercoating layer and the top coating layer was the most excellent, and thus it was found that the A-type composition ratio was the most suitable.

≪ Example 3 > Preparation of Top Coating Composition

The upper coating composition is prepared by first coating 116 g of a water-soluble acrylic resin, 254 g of pure water and 32 g of dimethylaminoethanol (DMAE) While stirring, 1 g of pearl pigment, 1 kg of a polytetrafluoroethylene (PTFE) paste having a solid content of 55% by weight, and 310 g of a perfluoroalkoxy (PFA) resin having a solid content of 35% by weight were charged.

After sufficiently stirring, 40 g of triethanolamine (TEA), 88 g of dispersant, and 159 g of pure water were added and sufficiently stirred, followed by filtration with a 300-mesh filter (A3-type).

The coating compositions were also prepared from B3-type to E3-type by the same method as above, and composition ratios of the respective components are shown in Table 3 below.

Preparation of Top Coating Composition Composition ratio ingredient Content (g) / Component ratio (% by weight) Remarks A3-type B3-type C3-type D3-type E3-type Water-soluble acrylic resin 116 / 5.8 145 / 5.8 166 / 5.8 89 / 5.8 105 / 5.8 Weight average molecular weight 10000 to 25000 Pure water 254 / 12.7 318 / 12.7 363 / 12.7 194 / 12.7 231 / 12.7 DMAE 32 / 1.6 40 / 1.6 46 / 1.6 24 / 1.6 29 / 1.6 Elementis-Deuchem Pearl pigment 1 / 0.05 1.3 / 0.05 1.4 / 0.05 0.8 / 0.05 0.9 / 0.05 IRIODIN, Merck 55 wt% PTFE 1000/50 1000/40 1000/35 1000 / 65.5 1000/55 PTFE Dispersion D310, Daikin 35 wt% PFA 310 / 15.5 638 / 25.5 871 / 30.5 0/0 191 / 10.5 Dupon TEA 40/2 50/2 57/2 31/2 36/2 Dispersant 88 / 4.4 110 / 4.4 126 / 4.4 67 / 4.4 80 / 4.4 Triton X-100, Dow Chemical Pure water 159
/7.95 198.8
/7.95 227.1
/7.95 121.4
/7.95 144.5
/7.95 Sum 2000
/ 100 2501.1
/ 100 2857.5
/ 100 1527.2
/ 100 1817/4
/ 100

When the top coating composition prepared as shown in Table 3 was coated on the intermediate coating layer by the wet on wet method, the A3-type composition showed the best adhesion with the intermediate coating layer and the most excellent surface releasing property. However, the B3- type composition, when the proportion of the perfluoroalkoxy resin is high or the composition ratio of the polytetrafluoroethylene resin is increased as in the case of the D3-type and E3-type compositions, the gloss is decreased and yellowing phenomenon and surface cracks are generated a lot, .

≪ Example 4 >

The low viscosity A1-type to E1-type undercoating composition was coated on a stainless steel frying pan metal substrate at a pressure of 300 일반 using a general spray, followed by drying at 170 캜 for 20 minutes. After drying, The average thickness was 50 탆.

A high-viscosity A2-type or E2-type intermediate coating composition is coated on the dried undercoat layer at a pressure of 150 psi using a low-pressure spray, and then the wet coating method is applied in a wet-on- The E3-type topcoat composition was coated at 300 < 0 > C using a conventional spray and then dried at 380 [deg.] C for 25 minutes.

At this time, the A1-type primer coating composition, the A2-type primer coating composition, and the A3-type top coating composition were coated in one combination, and the other types of compositions were also coated in this manner. After the final coating, Were respectively 150 mu m and 50 mu m on average.

≪ Test Example > Property analysis of coating film of kitchen appliance

The physical properties of the coating film of the kitchen appliance in which the coating operation was completed in Example 4 were analyzed and the results are shown in Table 4, and the analysis method is as follows.

- Dissolvability (non-tackiness): It was tested 50 times by measuring whether the egg whites naturally fall off after heating for 30 seconds at 200 ℃.

- Pencil hardness: 10 ㎝ with 1 ㎏ / f force and 1 m / sec using pencil hardness tester and repeated 10 times.

- Adhesiveness: After making 100 checkerboards at intervals of 1 mm, adhere them with cellophane tape and calculate the number of peels.

- Impact resistance: A 500 g steel ball was dropped at a height of 30 cm to check whether the coating was peeled off.

- Water resistance: immersed in tap water and checked for swelling and peeling after 200 hours.

- Moisture resistance: Confirmation of swelling and peeling after standing for 72 hours at a temperature of 80 ° C and a relative humidity of 95%.

- Abrasion resistance: Using a Taber abrasion tester, the wheel material GS-17 was rotated 15,000 times at a rate of 60 rpm under a load of 3 kg and checked for damage to the coating.

- Stain resistance: After coating the surface of the film with a lubricant, leave it at 20 ℃ for 24 hours, wipe it with solvent and check for stains.

- Salt water resistance: It is boiled for 36 hours at 100 ℃ in 10% salt water, and check whether the film is eroded.

- Acid resistance: immersed in 98% acetic acid solution and after 24 hours, check for swelling, peeling, cracking, discoloration.

- Alkali resistance: After immersing in 5% sodium carbonate solution, check for swelling, peeling, cracking, discoloration of the film after 24 hours.

- Accelerated weathering: Using a sunshine weather meter to check for discoloration of the coating after 2000 hours of testing.

Results of physical property test Test Number A-type B-type C-type D-type E-type Dysplasia ○ ○ ○ ○ ○ Pencil hardness 4H 4H 4H 4H 4H Attachment 100/100 100/100 100/100 100/100 100/100 Impact resistance ○ ○ ○ ○ ○ Water resistance ○ △ △ ○ ○ Moisture resistance ○ × × ○ ○ Abrasion resistance ○ ○ ○ ○ ○ Stain resistance ○ ○ ○ ○ ○ Saltwater ○ ○ ○ △ △ Acid resistance ○ ○ △ △ × Alkali resistance ○ ○ △ △ △ Accelerated weathering ○ △ × △ × X: Cracks, exfoliation, and corrosion (poor). X: Cracks, peeling, corrosion (bad)
Note 2) A-type: A1-type + A2-type + A3-type / B-type or E-type: same as A-type

The results of Table 4 show that the non-tackiness, pencil hardness, adhesion, impact resistance, abrasion resistance, and stain resistance were not different among the groups, but in the water resistance and moisture resistance tests, the polyamideimide and polyether The peeling phenomenon was observed in the B-type and the C-type in which the content of the sulfone was out of the range of the present invention and the content of the thickener in the intermediate coating composition was small. From these results, it was found that the polyamideimide, The viscosity of the composition is appropriately adjusted so that the surface of the utensil, the undercoat layer, the undercoat layer and the intermediate coat layer are firmly bonded to each other to prevent penetration of moisture into the interlayer.

In the salt water resistance test, erosion occurred in the D-type and E-type in which the content of the thickener in the middle coating composition was large and the content of the perfluoroalkoxy resin in the top coating composition was small. It is considered that the content of the alkoxy resin is less than the proper level.

 In the acid resistance and alkali resistance tests, defects were observed in the B-type or E-type in the accelerated weathering test in C-type, D-type and E-type. The interlayer adhesion force due to viscosity, thermal stability, etc., have an influence on the chemical properties of the coating film and resistance to changes in the external environment.

As a result, the main factors influencing various physical properties required for the kitchen utensil include the inherent characteristics of each component constituting the coating composition, as well as the difference in viscosity depending on the kinds and contents of these components, It is analyzed that the characteristics of the coating film are determined by affecting the interlayer adhesion force.

1: kitchen utensil base layer, 2: undercoat layer, 3: intermediate coat layer, 4:

Claims (7)

10 to 20 parts by weight of N-methyl-2-pyrrolidone, 70 to 85 parts by weight of water, 10 to 20 parts by weight of a dispersant, 100 parts by weight of a polyether (hereinafter referred to as " polytetrafluoroethylene " 80 to 100 parts by weight of a polyamideimide paste (solid content 13 to 30% by weight), 1 to 5 parts by weight of an inorganic pigment, 25 to 35 parts by weight of aluminum oxide 10 to 20 parts by weight of silicon carbide, 10 to 20 parts by weight of silica sol (solid content 25 to 35% by weight), and 5 to 10 parts by weight of diacetone alcohol to prepare a undercoating composition;
Coating the undercoating composition on the surface of a kitchen utensil at a pressure of 100-500 ㎪ and drying at 50-280 캜 for 5-30 minutes to form a undercoat layer;
10 to 20 parts by weight of a water-soluble acrylic resin, 25 to 35 parts by weight of water, 1 to 5 parts by weight of dimethylaminoethanol, 0.5 to 5.0 parts by weight of pearl pigment, 100 parts by weight of a pearl pigment, 20 to 30 parts by weight of perfluoroalkoxy resin (solid content 20 to 50% by weight), 5 to 15 parts by weight of an acrylic dispersant, 2 to 6 parts by weight of a dispersant, 4 to 7 parts by weight of a thickener, ethylene glycol monobutyl ether 4 To 8 parts by weight of an inorganic pigment and 2 to 5 parts by weight of an inorganic pigment to prepare an intermediate coating composition;
Coating the dried coating composition on the dried coating composition at a pressure of 10 to 300; to form a coating layer;
7 to 13 parts by weight of a water-soluble acrylic resin, 30 to 50 parts by weight of water, 1 to 5 parts by weight of dimethylaminoethanol, and 0.05 to 0.5 parts by weight of pearl pigment in 100 parts by weight of a polytetrafluoroethylene paste (solid content 50 to 60% by weight) 25 to 35 parts by weight of perfluoroalkoxy resin (solid content 20 to 50% by weight). 2 to 6 parts by weight of triethanolamine and 5 to 10 parts by weight of a dispersant to prepare an upper coating composition; And
Coating the upper coating composition on the upper coating layer with a wet-on-wet method at a pressure of 100 to 500 ㎪ and drying the coating composition at 350 to 450 캜 for 5 to 50 minutes to form an upper coating layer; Coating method. The method according to claim 1,
Wherein the coating thickness of the undercoat layer and the upper coating layer is 10 to 100 占 퐉 and the thickness of the intermediate coating layer is 30 to 300 占 퐉. delete The method according to claim 1,
Wherein the viscosity of the top coat composition and the top coat composition is in the range of about 8 to about 15 seconds for cup # 3 and the viscosity of the intermediate coat composition is about 50,000 to about 100,000 centipoise. The method according to claim 1,
The inorganic pigments of the undercoating composition and the intermediate coating composition are titanium oxide, zinc oxide, magnesium oxide, zirconium oxide, iron oxide, cobalt oxide, chromium oxide, graphite, carbon nanotubes or carbon black,
Wherein the pearl pigment of the intermediate coating composition and the top coat composition is a mica-titanium oxide pearl pigment. The method according to claim 1,
Wherein the acrylic dispersant is a (meth) acrylic acid ester-based dispersant. The method according to claim 1,
Wherein the water-soluble acrylic resin of the intermediate coating composition and the top coat composition has a weight average molecular weight of 10,000 to 25,000.

Images