TW200538278A - Clear-coated stainless steel sheet - Google Patents

Abstract

This clear-coated stainless steel sheet includes a stainless steel sheet, a bottom layer formed on the steel sheet, and a top layer formed on the bottom layer, wherein the bottom layer is made of a chemical conversion coating which includes an aminosilane and/or an epoxysilane, the chemical conversion coating has a coating weight of 2 to 50 mg/m2, the top layer is made of a clear coating which includes a thermosetting resin including an acrylic resin having cross-linkable functional groups as a major constituent and a blocked isocyanate compound for cross-linking and curing the acrylic resin, the acrylic resin has a glass transition point of 30 to 90 DEG C and a number-average molecular weight of 3,000 to 50,000, and the clear coating has a thickness of 1 to 10 μm.

Description

200538278 IX. Description of the invention: L test service households ^: genus of winter truffles invention field The present invention relates to transparent coated stainless steel sheets used in household electrical equipment, construction materials, and 5 automotive parts. The steel sheet is treated with non-chromate and has excellent performance in extrusion molding ability, weather resistance, rain resistance, detergent resistance, and chemical resistance. BACKGROUND OF THE INVENTION In the case of squeezing a sheet product such as a stainless steel sheet, it has been conventional practice to perform a forming operation after applying a layer of lubricating oil and to remove the lubrication with a solvent or a degreasing agent after the forming operation. oil. However, the use of these lubricants deteriorates the crushing environment. In addition, since fluorocarbons and organic solvents used as degreasers deplete the ozone layer, the use of these degreasers is more strictly regulated and eventually banned. As for the use of lubricating oil, partly due to the problems related to waste fluid treatment and working environment, there has been a demand for transparent coated stainless steel sheets that can be extruded > without the need to apply oily quality to eliminate degreasing. In addition to having good lubricity, it is also responsible for the global environment in applications such as electrical equipment. 20 Transparent coated stainless steel sheets, due to the so-called "new house syndrome, Expected to have a transparent coating of acetic acid and chromate. In addition, 'as far as building materials' are concerned, the cost of transparent equipment that excels in weather resistance, rain resistance, and acid rain resistance has been established. Stainless steel 郐 is also expected. 5 200538278 The currently used transparent coated stainless steel sheets with good extrusion forming ability include those disclosed in Japanese Patent Application First Publication No. 2001-149860, of which The steel sheet is chromate-treated with a chromate solvent, and a curing agent such as melamine resin is used to change an epoxy resin, a polyester resin having an bisphenol skeleton and an ether group. And ester-based urethane resin, ester-based backbone, or carboxyl, or acrylic resin is cured by spreading a layer of polyolefin wax in a final coating. Because of these transparent coatings with good extrusion molding ability The stainless steel sheet contains a bisphenol-type skeleton, which has poor weather resistance, which limits its application. Furthermore, in indoor applications, these conventionally transparent coated stainless steel sheets can cause problems such as new house syndrome, Because melamine resin as a curing agent contains formaldehyde, Jiajun will be released during the curing process and thus appear in the coating, and because the hexavalent complex is mixed in the chromate treatment, although its amount is very C. Summary of invention 1 15 Summary of the invention Therefore, one of the objects of the present invention is to provide an environmentally friendly transparent coated stainless steel sheet, which has a coating clarity, weather resistance, rain resistance, and scratch resistance. , Detergent resistance, and chemical resistance, and its manufacturing method. 20 _After investigating the properties of thermosetting resins, osmium, chemical conversion agents, and coating conditions, we found An environmentally-friendly transparent coated stainless steel sheet and a method for manufacturing the same. Therefore, the present invention provides a transparent coated stainless steel sheet, the steel sheet comprising an expensive steel sheet, and one formed on the steel sheet. Bottom, and a 200538278

A top layer formed on the bottom layer, wherein the bottom layer is composed of a chemical conversion coating containing aminosilane and / or epoxy silane, and the chemical conversion coating has a coating weight of 2 to 50 mg / m2, and the top layer is It consists of a transparent coating containing a thermosetting resin. The thermosetting resin includes a 5 acrylic resin having a crosslinkable functional group as a main component, and an isocyanate blocker to crosslink and cure. The acrylic resin has a glass transition point of 30 to 90 degrees and a number average molecular weight of 3,000 to 50,000, and the transparent coating has a thickness of 1 to 10 microns. According to the present invention, it is possible to obtain an environmentally-friendly and transparently coated non- 10 15 Qian steel steel sheet. The steel sheet does not contain Jiajun and chromate, and has a coating clarity, weather resistance, rain resistance, It has excellent scratch resistance, detergent performance, and chemical resistance. Namely, the present invention can provide transparent coated stainless steel sheets for household electrical equipment and can be used as construction materials such as internal surface treatment materials and external surface treatment materials. 2: In the transparent coated stainless steel sheet of Mingzhi, the transparent coating has a weight ratio of the solid content of the thermosetting resin to 5 parts of the solid content of the polyolefin woven. T L, there is. [HI㈣ particles are recorded between 1 μm and 1 μm. [Implementing the cold type] The preferred embodiment or-= to 50 °, _light μ ^ heavy! Controlled at 2)), and then formed by baking and drying at 1 ::: = 20 200538278 (MT). When the coating weight is higher than 50 mg / m2, the amount of the water-soluble component in the chemical conversion agent will increase, thereby causing bubbles to be generated on the surface of the heavy layer. The coating weight should preferably be between 2 and 10 mg / m2. The chemical conversion treatment is performed by using a chemical conversion solvent containing an amino sulfite and a 5 / or an epoxy silane coupling agent. Examples of the aminosilane coupling agent include: N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane. 10 Examples of the epoxy silane coupling agent include: 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- glycidoxypropyltrimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane. The chemical conversion solvent may also include a polyethylene wax and a silica dioxide aggregate. 15 The chemical conversion solvent may be applied by an appropriate technique such as spray coating, roll coating, curtain flow coating, or electrostatic coating. Drying is done at least to evaporate water, which is usually carried out at a temperature of 60 to 140 degrees. If necessary, a known pretreatment such as alkaline degreasing or acidic or alkaline etching may be performed while this chemical conversion treatment is being performed. The 20 chromate conversion coating includes hexavalent chromium, although its amount is quite small. Not only is this harmful, when a chromate conversion coating is formed, the surface of stainless steel produces a yellow hue. In contrast, the chemical conversion coating in the present invention is both transparent and colorless. In addition, a transparent coating having a thickness of 1 to 10 micrometers is formed on this chemical conversion coating, and when it is baked at a surface temperature (MT) of a stainless steel sheet material between 1940 and 200 degrees 200538278, it can be Obtain a transparent coated steel sheet with high white purity and good weather resistance and good rainproof Europe required for building material products. Although this rain-proof property has not been fully understood, it is thought to be due to the following reasons. The trace amount of the water-soluble component of 5 in the chemical conversion coating is positioned on the coating surface. At the same time, the coated surface has a high hardness. As a result, even if a contaminant such as waste ash adheres to the surface, it does not substantially penetrate into the inside of the coating. In contrast, the contaminant is washed away with the water-soluble component positioned on the coated surface, resulting in a good rain resistance. 10 The transparent coating in the present invention includes a thermosetting resin having an acrylic resin, the acrylic resin having one or more coupleable g-energy groups selected from the following groups as a main group Serving: Jingji, Wenji, and Shixiyanji. The acrylic resin can be obtained by a conventional coating resin preparation method. Examples of acrylic resins that can be used include aliphatic or cyclic acrylic resins such as ethyl enolate, ethyl acrylate, isocyanate acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl acrylic acid Mg, ethyl methacrylate, isocyanate methacrylate, n-butyl butyl acrylate, n-hexylfluorenyl acrylic acid, cyclohexanacrylic acid, cyclohexylmethacrylic acid, and lauryldienoic acid. These resins can be obtained by reacting one or more non-functional monomers, wherein the non-functional monosystem is selected from the group of vinyl ethers: methyl vinyl ether, ethyl vinyl ether, η-propyl vinyl ether, And n-butyl ethylene ether; styrene monomers such as styrene and α-methylbenzyl ethylene; and acrylamide monomers having one or more functional groups containing a crosslinkable functional group such as meridian, weyl, Or acrylamide, η-methacrylamide, and diacetone of the polymerizable monomers of the stilbene group 9 200538278 propylamidine. The polymerizable monomer having a hydroxyl group is a compound having one or more hydroxyl groups and one or more polymerizable unsaturated double chains per molecule, and examples thereof include hydroxyalkyl esters such as 2-hydroxyethyl acrylate, 2- 5-hydroxyethyl methacrylate, light propyl acrylate, and hydroxypropyl methacrylate, and polymerizable vinyl monomers with lactone-denatured bases, such as Praccel FM1 to FM5 and Praccel FA -1 to FA-5 (sold by Daicel Chemical Industries, Ltd.). The polymerizable monomer having a carboxyl group is a compound having one or more carboxyl groups 10 and one or more polymerizable unsaturated double chains per molecule, and examples thereof include acrylic acid, acryl acrylic acid, itaconic acid, and maleic acid , And fumaric acid. The polymerizable monomer having a silane group is a compound having one or more silane groups and one or more polymerizable unsaturated double chains per molecule, and examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane , And methacrylic acid 15 propylpropyltriethoxysilane. As described above, the acrylic resin has a crosslinkable functional group such as a hydroxyl group, a carboxyl group, or a silane group. The acrylic resin may have two or more parentable S energy groups per molecule. In addition, the glass transition point of this resin is preferably between 30 and 90 degrees, and most preferably between 50 and 90 degrees. Under the f-shaped shape where the glass transition point of the resin is lower than 20 degrees, when the temperature on the surface of a steel sheet with the resin coating is generated due to friction and plastic processing of the steel sheet during continuous extrusion, When the temperature rises to 80 to 100 degrees, the coating will soften and the resin of the coating will adhere to the mold. On the other hand, in the case where the glass transition point is higher than the shout. Hai Xiyue said that the processability during coating was not good, which caused problems such as pinhole formation and poor homogenization. The number-average molecular weight of the acrylic resin is preferably between 3,000 and 50,000, and most preferably between 40,000 and 10,000. Since the number average molecular weight of the acrylic resin is coupled to the glass transition point of the resin ', by setting the molecular weight within the above range, the 5 glass transition points can fall within the above-mentioned preferred range. The cross-linking agent which is another component of the thermosetting resin component based on acrylic resin is a blocking isocyanate compound. The blocking isocyanate compound is a compound having two or more isocyanate groups per molecule, and examples thereof include any of the following using a blocking agent such as a compound, a ketone compound, an activated fluorenyl compound, ε-caprolide Polyisocyanates blocked by amine compounds, tertiary compounds, or specific compounds: aromatic diisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, and naphthalene diisocyanate; aliphatic diisocyanates; aliphatic diisocyanates; Isocyanates, such as hexamethylene diisocyanate, and polydiacid diisocyanates; cycloaliphatic di 15 isocyanates, such as isophorone diisocyanate, and cyclohexane diisocyanate; and biuret types of the above isocyanates Add product or isocyanate ring type add product. Organotin catalysts such as dibutyltin dilaurate can be used as dissociation accelerators for this blocking agent. Examples of commercially available products include Sumika Bayer Urethane Co., Ltd. products such as Desmodur 20 BL1100, BL1265MPA / X, VPLS2253, BL3475BS / SN, BL3272MPA, BL3370MPA, BL4265SN, Desmosani 2170, and Sumidur 3175; Asahi Chemical Industry Co., Ltd. products such as Duranate 17B-60PX, TPA-B80X, MF-B60X and MF-K60X; Dainippon Ink and Chemicals, Inc. products such as 11 200538278

Burnock DB-980K, D-550, B3-867, and B7-887-60; and products of Nippon Polyurethane Industry Co., Ltd. such as Coronate 2515, 2507, and 2513, and either one of the above products or one by two One or more are selected from a mixture of the above products. 5 The relative proportion of the resin and the cross-linking agent in the thermosetting resin composition based on the acrylic resin can be changed within a wide range according to the desired purpose. In detail, the amount of the isocyanate group is preferably set to 0.3 to 2.0 molecules per molecule of the total number of OH groups and COOH groups in the acrylic resin. The terminal functional group and the side chain 10 in a molecule of a resin base agent may be selected from a hydroxyl group, a carboxyl group, and a silane group. The transparent coating may also include a curing catalyst to accelerate curing. Examples of the curing catalyst include dibutyltin dilaurate and 4-n-butyl 1,3-bistinacetic acid ditin oxide monoalkylene. If necessary, these catalysts may be used in combination. The coating preparation for forming the transparent coating layer may also include additives such as 15 leveling agents, foam inhibitors, antioxidants, ultraviolet absorbers, delusterant, and silicon coupling agents. In addition, a pigment or dye may be additionally dispersed in the coating preparation to make a colored transparent coating. If necessary, other resins such as epoxy resin, silicone resin, fluorescent resin, or polyester resin may be included. 20 In the present invention, the above-mentioned thermosetting resin composition preferably includes the weight of the solid content of polyolefin waxes of 0.25 to 5.0 per 100 parts by weight of the solid content of the above-mentioned thermosetting resin composition. Proportion. Examples of the polyolefin wax include hydrocarbon waxes such as paraffin wax, microcrystalline wax, polyethylene wax, and fluorine-containing polyethylene wax. As the transparent coated stainless steel sheet of the present invention is processed, the temperature of the transparent 12 200538278 coating will rise due to the high temperature generated by processing operations and friction. The melting point of the wax should preferably be between 70 and 160 degrees. between. In the case where the melting point is lower than 70 degrees, the wax will soften and melt when the transparent coated stainless steel sheet is processed, so that the butterfly cannot exhibit the good properties of a solid lubricant additive. On the other hand, in the case where the melting point is higher than 160 degrees, hard particles will appear on the surface, thereby reducing the friction characteristics, and making the transparent coated stainless steel sheet impossible to achieve high processability. The polyolefin wax preferably has an acid value between 0 and 30. In the case where the acid value is higher than 30, the wax has good compatibility with the resin and does not evenly rise to the surface of the coating, thereby preventing the transparent coated stainless steel sheet from reaching a sufficient level. Workability. The particle diameter of these wax particles is preferably between 0.1 and 7.0 microns. Wax particles larger than 7.0 microns in diameter should be avoided because the wax distribution after solidification will not be uniform. On the other hand, in the case where the particle diameter is less than 0.1 micrometer, the 15 transparent coated stainless steel sheet cannot achieve sufficient workability. The amount of the solid component of the polyolefin wax is preferably 0.25 to 5.0 parts by weight per 100 parts by weight of the resin solids of the thermosetting resin composition. In the case where the solid content of the polyolefin wax is less than 0.25 parts by weight, the transparent coated stainless steel sheet cannot achieve sufficient workability. In the case where the solid content of the polyolefin 20 wax is more than 5.0 parts by weight, the surface of the coating layer may be uneven, thereby deteriorating the appearance of the transparent coated stainless steel sheet. Examples Examples and comparative examples of the present invention are described below. In these examples, "part" and "percent" are in terms of weight. 13 200538278 A four-necked flask equipped with a thermometer, a reflux condenser, a stirrer, a dropping funnel, and a nitrogen inlet were filled with specific amounts of toluene and butyl acetate, as shown in Table 1. The temperature was then raised to 110 ° C, and when nitrogen was blown in and the contents of the flask were stirred, methyl methacrylate, η-butyl 5 methyl acrylate, 2-hydroxyethyl phosphoacrylate, and fluorenyl acrylic acid A mixture of an ester and azobisisobutyrene (AIBN) was added to the flask in a dripping manner over a period of 3 hours. After the addition was completed, azobisisobutyrene was further added and the reaction was continued at the same temperature for 3 hours, and finally an acrylic copolymer having a non-volatile content of 50% was produced. 10 A coating material for the top layer is prepared by preparing a transparent coating material, as shown in Table 1. Table 1 Thermosetting resin

A-1 A-2 A-3 A-4 B-1 B-2 Benzene 25.0 25.0 25.0 25.0 25.0 25.0 Butyl acetate 24.0 24.0 24.3 24.3 23.0 24.5 Acrylic methacrylate 16.0 16.0 29.0 29.0 5.0 40.5 Styrene 5.0 5.0 5.0 5.0 4.0 η-butyl methacrylate 19.5 19.5 6.5 6.5 35.5 Acrylic resin 2-hydroxyethylmethacrylate 9.0 9.0 9.0 9.0 5.0 2-Ethyl acetate 9.0 Methyl acrylate 0.5 0.5 0.5 0.5 0.5 0.5 Even Azodiisocyanate (ΑΙΒΝ) 1.0 1.0 0.7 0.7 2.0 0.5 Average molecular weight 5,000 5,000 20,000 20,000 2,500 60,000 Glass transition point (° C) 60 60 80 80 20 100 Blocking isocyanate compound (crosslinking agent) Desmodur VPLS2253 (NC0 content , 10.5%) 20 40 20 40 20 20 14 200538278-Polyester / melamine resin coating material (Kawakami Toryo KK) is used as the transparent coating material in some comparative examples. SUS 430 stainless steel sheet with a fourth polished surface finish is used as the metal sheet. 5 Chemical conversion coating solvent was applied to the stainless steel with a roll coater under fluorescent X-ray analysis under the condition that the weight of the dioxide on the stainless steel sheet was set to 2 to 50 mg / m2. The sheet was then dried at a steel sheet temperature C (Mτ) of 100 degrees. Next, the transparent, coating material was coated on it with a bar coater and baked at a steel sheet temperature (MT) of 193 degrees, thereby producing Tables 102-1 and 2-2. A transparent coated stainless steel sheet is shown as an example of the present invention. For comparison, a transparent coated stainless steel sheet having a transparent coating lacking the characteristics of the present invention, a transparent coated stainless steel sheet having a chromate conversion coating as a chemical conversion coating, and a transparent coating lacking a chemical conversion coating The 15-coated stainless steel sheet was treated in the same manner as in the above example of the present invention, thereby producing the stainless steel sheets in Comparative Examples 26 to 37 shown in Tables 3-1 and 3-2. The resulting samples were tested for coating clarity, scratch resistance, rain resistance, detergent resistance, chemical resistance, and weather resistance, as well as the Edchsen 20 test. The results are shown in Tables 2-1, 2-2, 3-1, and 3-2. 15 200538278 Table 2-1 Examples of the present invention

Item Chemical conversion coating Transparent coating Polyolefin wax Yes / No Coating material Coating weight (mg / nr) Type thickness (micron) Wax amount (pbw) Particle ruler + 1 is amino silane 2 A-1 2 — One 2 is amino smash 10 A-1 2--3 is amino silane 30 A-1 2 one-4 is amino silane 50 A-1 2--5 is epoxy silane 2 A-1 2- --6 is epoxy silane 10 A-1 2--7 is epoxy silane 30 A-1 2--8 is epoxy silane 50 A-1 2--9 is amino crushed + epoxy Silane 2 A-1 2-— 10 is amino silane + epoxy silane 10 A-1 2-— 11 is ammonia 夕 Xiyao + epoxy silane 30 A-1 2-— 12 is ammonia; ^ ^ Xiyaki + epoxy silane 50 A-1 2--13 is amino burned 10 A-2 2 — — 14 is amino silane 10 A-3 2 — — 15 is amino silane 10 A-4 2-- 16 is aminosilane 10 A-1 1--17 is aminosilane 10 A-2 1--18 is aminosilane 10 A-3 10--19 is aminosilane 10 A-4 10 a- -20 is amino silane 10 A-1 2 0.3 2.5 21 is epoxy silane 10 A-1 2 2 2.5 22 is amino crushed + silicon epoxy 10 A-1 2 5 2.5 23 is aminosilane 10 A-2 2 0.3 2.5 24 is epoxy resin 10 A-3 2 2 2.5 25 is aminosilane + epoxy silane 10 A-4 2 5 2.5 16 200538278 Table 2-2 Examples of the invention

Item Coating properties Release of formaldehyde and hexachromeΐ Note Coating clarity Scratch resistance Rain-proof cleaner Resistance chemical resistance Weatherability Formability Salt-water splash resistance 1 0.6 5H 5 5 5 5 8.4 5 Good No 2 0.5 5H 4 4 5 5 8.4 4 Good No 3 0.8 5H 5 5 4 5 8.3 5 Good No 4 0.5 5H 4 5 5 5 8.4 4 Good No 5 0.3 5H 5 5 5 8.6 4 Good No 6 0.5 6H 5 5 5 5 8.5 4 Good 7 0.4 5H 5 5 5 5 8.4 5 Good 8 8 5 5H 5 4 5 5 8.5 5 Good 9 9 6 6 5 5 5 5 8.4 5 Good 10 0.3 5H 5 5 5 5 8.6 5 Good 11 11 5 5H 5 4 5 5 8.5 5 Good 12 12 5 5H 5 5 5 5 8.4 5 Good 13 13 5 5H 5 4 5 5 8.5 5 Good 14 14 6 6 5 5 5 8.3 5 Good 15 0.8 5H 4 5 5 4 8.2 4 Good 16 16 5 5H 5 5 5 8.5 5 Good 17 17 5 5H 5 5 5 8.3 5 Good 18 18 6 6 5 5 5 5 8.4 5 Good 19 0.2 6H 4 4 5 5 10 5 Excellent No 20 0.5 5H 5 5 5 5 9.7 5 Excellent No 21 0.4 5H 5 5 5 5 9.8 4 Excellent No 22 0.6 5H 4 5 5 5 10 4 Excellent No 23 0.5 5H 5 5 5 9.9 5 Excellent No 24 0.4 5H 5 5 5 5 9.5 4 Excellent No 25 0.6 5H 4 5 5 5 9.5 4 Excellent No 17 200538278 Table 3-1 Comparative example item Chemical conversion coating Clear coating Polyolefin wax Yes / No Coating material Coating weight # (mg / m2) Type thickness (micron) Wax amount (pbw) Particle size 26 No ~ One A-1 2 ~-27 No-A-2 2 ~ 28 Yes Chromate 10 A-1 2 2 2.5 29 is chromate 30 A-1 2 2 2.5 30 is chromate 10 polyester / melamine 1 2 2.5 31 is chromate 10 polyester / melamine 2 2 2.5 32 is chromate 20 polyester / Melamine 2 2 2.5 33 is chromate 30 polyester / melamine 2 5 2.5 34 is aminosilane 10 Polyester / melamine 2 2 2.5 35 is aminosilane 10 Polyester / melamine 2 5 2.5 36 is aminosilane 10 B-1 2 2 2.5 37 is amino > 5 yakiya 10 B-2 2 2 2.5

Table 3-2 Comparative example Item Sub-coating properties Release of acetaldehyde and hexavalent chromium Note Coating clarity Scratch resistance Rain-proof cleaners Chemical resistance Weather resistance Formability Salt-water spray resistance 26 -~-~-~ ~ Poor or poor adhesion 27-~ ~-~ — —-Poor or poor adhesion 28 1.5 5H 5 5 5 5 9.5 5 Poor is 29 2.8 5H 5 5 5 5 9.8 5 No Good 30 2 3H 3 3 1 2 9.3 3 Poor 31 31 3 3 2 3 1 2 9.5 3 Poor 32 2.4 3H 3 3 1 2 9.7 3 Poor 33 3.1 4H 2 3 1 1 9.5 4 Poor Yes 34 0.5 3H 2 3 1 2 9.5 3 Poor 35 0.6 3H 2 3 1 1 9.4 4 Poor is 36 0.4 3H 5 5 5 5 9.8 5 Poor 37 37 6 6H 5 5 5 5 9.4 5 Poor Defectiveness 18 200538278 The following method was used to evaluate the coating (1) Coating clarity The color state of the coating was measured with a CR-300 color difference meter (produced by Minolta Co., Ltd.) as 193 The color difference Ab value between the 5 pieces of steel baked at the steel sheet temperature and the transparent coated stainless steel sheet. Here, higher Ab means higher yellowness. (2) Scratch resistance The test sample was evaluated according to the pencil scratch resistance test method described in JIS K5400. Here, a rating of 5H or higher is considered a qualifying item. 10 (3) Rain resistance The test samples were subjected to a three-month environmental exposure test, and the degree of rain marks formed on the coating was rated. 5: No traces (pass) 4: Weak traces are visible (pass) 15 3: Traces are quite obvious (fail)

2: Leaving severe marks (failed) 1: Delamination (failed) (4) The detergent property test sample was immersed in Magiclean (cleaner manufactured by Kao 20 Corporation) at 40 ° C ) For 72 hours, after which the condition of the coating was inspected and rated. 5: No traces (pass) 4: Weak traces (pass) 3: Traces are quite obvious (fail) 19 200538278 5 Ο 10 15 Ο 20 2: Severe marks remain (fail) 1: Peeling ( (Failure) (5) Resistance After dropping 2 ML of 5% sulfuric acid and 5% NaOH into the test sample, a carcass was placed on the sample, and the sample was left for 16 hours. The condition of the coating was then observed and rated. 5. No traces 4: Weak traces are visible 3: Traces are quite obvious 2: Severe traces are left 1: Peeling occurs (6) Weatherability (%) after 1000 hours of weather resistance M) The test is rated. 5: 80 to 100% gloss maintenance (pass) 4: 60 to 80% gloss maintenance (pass) 3: 40 to 60% gloss maintenance (fail) 2: 20 to 40% gloss maintenance Degree (Failure) 1: 0 to 20% gloss retention (Failure) (7) Erichsen value The Enchsen value is rated according to JIS Z2247. Since the value of 9 3 mn ^ Erkhsen is obtained when graphite grease is used in SUS43 ° steel sheet, a value higher than this value is considered acceptable. & n (8) Saltwater Spatter Resistance (Passed) (Passed) (Failed) (Failed) (Failed) (Failed) 20 200538278 The coating was cut transversely and the saltwater splash resistance test was based on The method described is carried out for an hour, and then the coating is subjected to "visual inspection and evaluation." Peeling degree below 5% 4: Peeling degree from 5 to 10% (pass) 3: Peeling degree from 10 to 15% (Failure) 2: Degree of peeling from 15 to 20% (Failure) 1: Degree of peeling of 20% or higher (Failure) 10 As shown in the above description and examples, the present invention provides a Hexavalent chromium is a transparent coating that can take care of the global environment and excels in coating clarity, scratch resistance, rain resistance, detergent resistance, chemical resistance, and weather resistance. In addition, By adding 0.25 to 5 parts by weight of each solid ingredient in the weight ratio, a transparent coated stainless steel with excellent lubrication can be obtained. Steel sheet, its formability is better than oil-based lubrication and cold bearing sheet. 旻 of stainless steel 20 compared with In the absence of chemical conversion treatment, the transparent coating performed poorly. Chromate conversion coating produced in the lack of steel sheet will produce a yellow hue and contain a hexavalent network, making it Dong = = steel good. In the past, "/ melamine coating" was unsatisfactory, rain-proof, detergent resistance, chemical resistance, and ^ 'poor, and possible Formaldehyde is released. In the case that the thermosetting resin of the thermosetting tree ore has a molecular weight outside the range of 3,000 to 50,000 and a glass transition point exceeding 30 to 90 degrees, it is coated The stainless steel 21 200538278 steel sheet has several disadvantages, including poor scratch resistance and poor manufacturability. The present invention provides a formaldehyde and chromate-free coating with clear, weather-resistant and rain-resistant coatings. Environmentally friendly transparent coated stainless steel sheet with excellent scratch resistance, detergent resistance, and chemical resistance. The transparent coated 5 coated stainless steel sheet is suitable for domestic electrical equipment and can be used as an internal surface treatment Materials and exterior surface treatment materials. Brief Description of the drawings] (none) [REFERENCE NUMERALS main element (None) 22

Claims (1)

200538278 10. Scope of patent application: 1. A transparent coated stainless steel sheet, comprising: a stainless steel sheet; a bottom layer formed on the steel sheet; and a top layer formed on the bottom layer, wherein the bottom layer consists of a A chemical conversion coating comprising aminosilane and / or epoxy silane. The chemical conversion coating has a coating weight of 2 to 50 mg / m2. The top layer is composed of a transparent coating containing a thermosetting resin. The thermosetting resin includes an acrylic resin having a crosslinkable functional group as a main component, and an isocyanate compound that blocks to crosslink and cure the acrylic resin. The acrylic resin has 30 to 90 Degree of glass transition point and a number average molecular weight of 3,000 to 50,000, and the transparent coating has a thickness of 1 to 10 microns. 2. The transparent coated stainless steel sheet according to item 1 of the patent application range, wherein the transparent coating has a solid content of 0.25 to 5 polyolefin waxes in a weight ratio of the solid content per 100 thermosetting resins. By weight. 3. The transparent coated stainless steel sheet according to item 2 of the patent application, wherein the polyolefin wax has a particle diameter between 0.1 and 7 microns. 23 200538278 7. Designated Representative Map: '(1) The designated representative map in this case is: (). (None)-(II) Brief description of the component symbols in this representative drawing: 8. If there is a chemical formula in this case, please disclose the chemical formula that can best show the characteristics of the invention: