TWI296566B - Clear-coated stainless steel sheet - Google Patents

Description

1296566 IX. INSTRUCTIONS: H 冬长J 】 Field of the Invention The present invention relates to a transparent coated stainless steel sheet for use in household electrical equipment, building materials, and applications such as five-car parts, which are non-chrome The acid salt treatment is excellent in extrusion molding ability, weather resistance, rain resistance, main agent resistance, and chemical resistance.

L mf BACKGROUND OF THE INVENTION 10 In the case of extrusion forming a sheet product such as a stainless steel sheet, the past indignation was that a coating operation was carried out after applying a layer of lubricating oil and a solvent or alkaline degreaser was removed after the forming operation. In addition to the lubricant. However, the use of such lubricating oils deteriorates the crushing environment. In addition, since the gas stone households and organic solvents used as degreasers deplete the ozone layer, the use of these degreasers is more strictly regulated and finally banned at the end. As for the use of lubricating oil, Department 8 has a need to eliminate the need for oil removal by eliminating the need for oil-coated transparent coated stainless steel sheets due to problems associated with waste fluid handling and the working environment. In addition, the company is responsible for the global environment with a good lubricity. Regarding the use of 2" transparent coated non-steel steel sheets for applications such as household electrical equipment, due to the so-called "new housing syndrome, and related problems, there is a transparent coating of stainless steel sheets containing no formaldehyde and chromate. Expectations have also been made. In addition, in terms of building materials, there are also expectations for transparent coated stainless steel sheets that are excellent in weather resistance, alpha, rain resistance, and acid rain resistance.

The transparent coated steel sheet which has a good pressure-masking ability, which is currently used, includes the one disclosed in Japanese Laid-Open Patent Publication No. 2001-149860, wherein the steel sheet is permeated with a chromic acid. The salt solvent is subjected to chromate treatment, and a curing agent such as melamine resin is used to make an epoxy-based 5-ester polyester resin, an ether group having a bisphenol skeleton, an ester-based urethane resin, an ester group skeleton, or a carboxyl group, or The acrylic resin is thermally cured to spread a layer of polyolefin wax in a final coating. Since these transparent coated steel sheets having good press forming ability contain a double type of skeleton, they have poor weather resistance and thus limit their application. Furthermore, in indoor applications, these conventionally coated stainless steel sheets can cause problems such as new house syndrome, because the melamine resin as a curing agent contains furfural, and formaldehyde is released during the curing process. This occurs in the coating, and because hexavalent chromium is mixed in the chromate treatment, although it is very rare. L. OBJECT 3 15 SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an environmentally friendly, transparently coated stainless steel sheet that is clear, weather resistant, rain resistant, and scratch resistant. Excellent performance in terms of detergent resistance and chemical resistance, and its manufacturing method. After investigating the properties of thermoset resins, waxes, chemical converters, and coating conditions, we found an environmentally friendly, transparently coated stainless steel sheet and its method of manufacture. Accordingly, the present invention provides a transparent coated unrecorded 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 is Consisting of a chemical conversion coating comprising an amino stone and/or an epoxy, the chemical conversion coating having a coating weight of 2 to 50 mg/m 2 'the top layer is composed of a thermosetting resin, month The coating composition, the edge thermosetting tree comprises a 5-acrylic resin having a crosslinkable functional group as a main component and a blocking isochlorinated compound for crosslinking and curing the acrylic The resin, the acrylic resin having a glass transition point of from 30 to 90 degrees and a number average molecular weight of from 3,000 to 5 Å, and the clear coating layer has a thickness of from 丨 to . According to the present invention, an environmentally friendly, non-recorded steel sheet is obtained which is free of sulphur and chromate and which is coated with clarity, weather resistance, rain resistance, scratch resistance. Excellent performance in terms of detergent resistance and chemical resistance. Accordingly, the present invention can provide a transparent coated stainless steel sheet suitable for use in household electrical equipment and as a building material such as an internal surface treatment material and an external surface treatment material. In the transparent coated stainless steel sheet of the present invention, the clear coat layer may have a weight ratio of 0.25 to 5 solid parts of the polyolefin wax in a weight ratio of the solid content per 100 thermosetting resins. The polyolefin wax may have a particle diameter of between 01 and 7 microns. C. In a preferred embodiment, in the practice of the present invention, the chemical conversion agent comprises an amino decane and/or an epoxidized stone, and through a treatment, wherein a coating weight is controlled at 2 Between 50 mg/m2 (weight of cerium oxide measured by fluorescent calorimetry), then baked and dried at a surface temperature of 7 1296566 (MT) between 60 and 140 degrees stainless steel sheet material And formed. At a coating weight of more than 50 mg/m2, the amount of the water-soluble component in the chemical conversion agent increases, which in turn contributes to the generation of bubbles on the surface of the coating. The coating weight is preferably between 2 and 10 mg/m2. The chemical conversion treatment is carried out by using a chemical conversion solvent containing an aminoguanidine coupling agent and a 5 / or an epoxy decane coupling agent. Examples of such amino decane coupling agents include:

N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane ^ N-2-(aminoethyl)-3-aminopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane. Examples of the epoxy decane coupling agent include: 2-(3,4-epoxycycl〇hexyl)ethyltrimethoxysilane, 3- glycidoxypropyltrimethoxysilane, and 3-glycidoxypr〇pyimethyldiethoxysilane. The chemical conversion solvent may also comprise a polyethylene wax and a cerium oxide aggregate. The chemical conversion solvent can be applied by a suitable technique such as a spray coating method, a roll coating method, a curtain flow coating method, or an electrostatic coating method. Drying is at least to evaporate moisture, which is usually carried out at a temperature of 6 to 14 degrees. If necessary, a known pretreatment such as an analytical degreasing or an acid or an in-progress may be performed while this chemical conversion treatment is being carried out. The chromate conversion coatings include hexavalent chromium, although the amount is quite small. This is not only harmful, but when a chromate conversion coating is formed, the surface of the stainless steel produces a yellow hue. In contrast, the chemical conversion coating in the present invention is both transparent and colorless. In addition, a clear coating having a thickness of 1 to 10 μm is formed on the chemical conversion coating layer and a stainless steel sheet material having a surface temperature of 19 to 240 degrees 8 丄 6656 has a high white purity and has a build-up. Material production =;: roasting %, can obtain a transparent net with rain resistance. 2 Good weatherability and good solution n / This rain-proof property has not been completely treated with water, = the following reasons. The trace amount of the 4 components in the chemical conversion coating was positioned on the coated surface. (4) The coated surface has a high hardness. As a result, even if a contaminant such as a waste ash adheres to the surface, it does not substantially penetrate the inside of the coating. Conversely, the stain

The dye and the (10) coated surface of the miscellaneous ingredients - are washed away, resulting in a good rain resistance. The clear coating of the tree consists of a thermosetting resin having a acryl resin having one or more crosslinkable functional groups selected from the group consisting of: Hydroxyl, carboxyl, and decyl. The acrylic resin can be obtained by a conventional coating resin preparation method. Examples of acrylic resins that may be used include aliphatic or cyclic acrylates such as methyl propionate, ethyl acrylate, isocyanate acrylate, n-propionate, 2-ethylhexyl acrylate, methacrylic acid. Methyl ester, ethyl methacrylate, isocyanate methacrylate, butyl butyl butyl acrylate, η-hexyl methacrylic acid, cyclohexacrylic acid, cyclohexyl methacrylic acid, and lauryl methacrylic acid. These resins are obtainable by reacting one or more non-functional monomers selected from the group consisting of the following vinyl ether groups: methyl ethylene ethyl vinyl _, } propyl ethylene _, and Heart butyl ethoxylate; styrene monomer such as styrene and oc-methyl styrene; and acrylamide monomer such as having one or more crosslinkable functional groups such as Base, or calcined polymerizable monomer of acrylamide, η-methyl acrylamide, and diacetone 9 1296566 acrylamide. 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 a transalkylalkyl ester such as 2-hydroxyethyl acrylate, 2 - Hydroxyethyl methacrylate 5 ester, propyl acrylate, and propyl methacrylate, and polymerizable ethylenic monomers with lactone-modified hydroxyl groups, such as Praccel FM1 to FM5 and Praccel FA -1 to FA, 5 (Daicel Chemical Industries, Ltd.

The company is sold by). 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, mercaptoacrylic acid, itaconic acid, maleic acid. And anti-succinic acid. The polymerizable monomer having a mercaptoalkyl group is a compound having one or more mercapto groups and one or more polymerizable unsaturated double chains per molecule, and examples thereof include vinyl trimethoxy decane and vinyl triethoxy group. Base decane, and methacryl 15 acid propyl propyl ethoxy decane. In view of the above, the acrylic resin has a crosslinkable functional group such as a hydroxyl group, a carboxyl group, or a decyl group. The acrylic resin may have two or more crosslinkable functional groups per molecule. Further, the glass transition point of the resin is preferably between 3 Torr and 9 Torr, preferably between 50 and 90 deg. In the case where the glass transition point of the resin is 20 to 30 degrees lower, the temperature on the surface of a steel sheet having the resin coating rises due to the friction of the steel sheet during continuous compression and the high temperature generated by plastic processing. At 80 to 1 turn, 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 9 Torr, the resin has poor workability at the time of coating, which in turn causes pinhole 10 1296566 to open 70% and a problem of poor homogenization. The acrylic resin has a number average molecular weight i and is between 3,000 and 50,000, preferably between 4 Torr and 1 Torr (8). Since the number average molecular weight of the ruthenium resin is coupled to the glass transition point of the resin, by setting the molecular weight within the above range, the glass transition point can fall within the above preferred range. The crosslinking agent which is another component of the thermosetting resin component based on the acrylic resin is a blocking isocyanate compound.

The blocked isocyanate compound is a compound having two or more isocyanato- oligoester groups per molecule, and examples thereof include any of the following: a blocking agent such as a sulfonated compound, a ketoxime compound, an activated fluorenylene compound, Polyisocyanate blocked by ε-caprolactam compound, triazole compound or azole compound: aromatic diisocyanate, such as toluene diisocyanate, diphenyl sulfonium diisocyanate S 曰, 曱 一 monoisocyanate Cool, and naphthalene diisocyanate; aliphatic diisocyanate, such as hexamethylene diisocyanate, and polyisocyanate diisocyanate; alicyclic di 15 isocyanate, such as isophorone diisocyanate, and ring Hexane diisocyanate; and a biuret type addition product or an isocyanate ring type addition product of the above isocyanate. An organotin catalyst such as dibutyltin dilaurate can be used as a dissociation accelerator for the blocker. Examples of commercially available products include products of Sumika Bayer Urethane Co., Ltd. such as Desmodur 20 BL1100, BL1265MPA/X, VPLS2253, BL3475BS/SN, BL3272MPA, BL3370MPA, BL4265SN, Desmosam 2170 and Sumidur 3175; Asahi Chemical Products of Industry Co·, Ltd. such as Duranate 17B-60PX, TPA-B80X, MF-B60X and MF-K60X; Dainippon Ink and Chemicals, Inc. products such as 11 1296566

Burnock DB-980K, D-550, B3-867 and B7-887-60; and Nippon Polyurethane Industry Co., Ltd. products such as Coronate 2515, 2507 and 2513, and any of the above products or one by two One or more mixtures selected from the group consisting of the above products. 5 the resin and the crosslinking agent are based on the thermosetting resin based on the acrylic resin

The relative proportions in the resin composition can be varied within a wide range depending on the intended purpose. In particular, the amount of the isocyanate group is preferably set to be from 33 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 one molecule of a resin main agent may be selected from a hydroxyl group, a carboxyl group, and a decyl group. The clear coat may also include a curing catalyst to accelerate curing. Examples of the curing catalyst include dibutyltin dilaurate and 4-n-butyl 1,3-diacetate ditin epoxide. These catalysts can be used in combination if necessary. The coating preparation for forming the clear coat layer may also include additives such as a 15 leveling agent, a foam inhibitor, an antioxidant, a UV absorber, a delusterant, and a sinter. In addition, a pigment or dye may be additionally dispersed in the coating preparation to form a colored clear coating. Other resins such as epoxy resins, enamel resins, fluorescent resins, or polyester resins may also be included if necessary. In the present invention, the thermosetting resin composition preferably comprises a weight ratio of 〇25 to 5 聚烯烃 of the solid content of the polyolefin wax per part by weight of the solid content of the above-mentioned thermosetting resin composition. Share. Examples of polyolefin waxes include hydrocarbon waxes such as paraffin wax, microcrystalline wax, polyethylene wax, and fluorine-containing polyethylene wax. Due to the processing of the transparent coated stainless steel sheet of the present invention, the temperature of the transparent 12 1296566 coating will rise due to the high temperature generated by the Garry and the friction, and the soil is bright and at 7 〇. Between 16 degrees. In the case where the refining point is less than %, the sputum softens and refines when the 4 transparently coated stainless steel sheets are processed, so that the wax does not exhibit the good properties of the solid lubricating additive. On the other hand, in the case where the melting point is higher than 160 degrees, hard particles are present on the surface, thereby lowering the friction characteristics, and the transparent coated stainless steel sheet cannot achieve south workability.

The acid value of the polyolefin is preferably between 30 and 30. In the case where the acid value is higher than 30, the wax has good compatibility with the resin and does not uniformly apply 10 liters to the surface of the coating, so that the transparent coated stainless steel sheet cannot be fully achieved. Machinability. The particle diameter of these wax particles should be at (1) 丨 to? " between micrometers. Wax particles larger than 7.0 microns in diameter should be avoided because the distribution of wax after solidification is not uniform. On the other hand, in the case where the particle diameter is less than 0.1 μm, the 15 transparently coated stainless steel sheet cannot achieve sufficient workability. The amount of the solid component of the polyolefin wax is preferably from 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 amount of the solid component of the polyolefin wax is less than 0.25 by weight, the transparent coated stainless steel sheet cannot achieve sufficient workability. In the case where the amount of the solid component of the polyolefin 20 wax is more than 5.0 parts by weight, the surface of the coating layer may be uneven, thereby impairing the appearance of the transparent coated stainless steel sheet. EXAMPLES Examples and comparative examples of the present invention are explained below. In these examples, "parts" and "percent" are by weight. 13 I296566—A four-necked flask equipped with a thermometer, a reflux condenser, a stirrer, a commercial funnel, and a nitrogen inlet were filled with a specific amount of toluene and butyl salt, as shown in Table 1. Then the temperature is raised to 11 degrees, and when the contents of the flask are stirred by blowing nitrogen, a decyl methacrylate, η-butyl methacrylate, 2-hydroxyethyl hydrazine acrylate, A A mixture of a acrylate and azo-isobutyl sulfonate was added to the flask in a dropwise manner over a period of 3 hours. After the addition is completed, azobisisotin is further added.

The reaction was added at the same temperature for 3 hours to finally produce an acrylic copolymer having 50% non-volatile content. A coating material for the top layer is prepared by modulating 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 Toluene 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 Methyl 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-hydroxyethyl methacrylate 9.0 9.0 9.0 9.0 5.0 2-Hydroxyethyl acetate 9.0 Methyl acrylate 0.5 0.5 0.5 0.5 0.5 0.5 Azobisisobutylidene (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 One 1C broken iso-lactic acid ester compound Desmodur VPLS2253 (NC0 content, 10.5%) 20 40 20 40 20 20 14 1296566 A polyester/melamine resin coating material (Kawakami Toryo KK) is used as the transparent coating material in some comparative examples. Four kinds of polished surface-treated SUS 430 stainless steel sheets are used as metal sheets. 5 Chemical conversion coating solvent is used as a rolling coater to measure the cerium oxide on the stainless steel sheet after fluorescent X-ray analysis. Set at 2 to 50mg / m2 of conditions is applied to the stainless steel plate, then the temperature of the steel sheet 1〇〇

(MT) dry. Next, the clear coating material was applied to it above a bar coater and baked at a sheet temperature (MT) of 193 degrees to produce the conditions shown in Tables 10 2-1 and 2-2. Transparent coated stainless steel sheet 0 of Examples 1 to 25 of the present invention For comparison, a transparent coated stainless steel sheet having a clear coating lacking the characteristics of the present invention, having a chromate conversion coating as a chemical conversion coating Transparent coated stainless steel sheets, and clear coated 15 stainless steel sheets lacking a chemical conversion coating are treated in the same manner in the above examples of the invention' to produce comparative examples shown in Tables 3-1 and 3-2. Stainless steel sheets from 26 to 37. The resulting samples were tested for coating clarity, scratch resistance, rain resistance, detergent resistance, chemical resistance, and weatherability, as well as the Erichsen 20 test. The results are shown in Tables 2-1, 2-2, 3-1 and 3-2. 15 1296566 Table 2-1 Examples of the invention

Chemical conversion coating clear coating polyolefin wax yes / no coating material coating weight # (mg / m2) type thickness (micron) soil amount (pbw) particle size 1 is amino decane 2 A-1 2 -- 2 is amino decane 10 A-1 2 -- 3 is amino decane 30 A-1 2 — — 4 is amino decane 50 A-1 2 — — 5 is epoxy decane 2 A-1 2 -- — 6 is a ring Oxane 10 A-1 2 -- 7 is epoxy decane 30 A-1 2 — 8 is epoxy decane 50 A-1 2 -- 9 is amino decane + epoxy decane 2 A-1 2 — — 10 is ammonia tomb ^ 夕烧 + epoxy decane 10 Α · 1 2 -- 11 is ammonia tombstone simmer + epoxy decane 30 A-1 2 -- -- 12 is ammonia smash + epoxy decane 50 A-1 2 — -- 13 is amino decane 10 A-2 2 — — 14 is amino decane 10 A-3 2 -- -- 15 is amino decane 10 A-4 2 -- -- 16 is amino decane 10 A-1 1 -- -- 17 is amino decane 10 A-2 1 -- 18 is amino decane 10 A-3 10 — — 19 is amino decane 10 A-4 10 -- -- 20 is amino oxime 10 A-1 2 0.3 2.5 21 is epoxy decane 10 A-1 2 2 2.5 22 is amino decane + Oxygen Silane 10 A-1 2 5 2.5 23 is an amino silane-10 A-2 2 0.3 2.5 24 an epoxy silane-10 A-3 2 2 2.5 25 amino broken burn + epoxy silane-10 A-4 2 5 2.5 16 1296566

Table 2-2 Example of the present invention Coating properties Furfural and hexavalent chromium release Note Coating clarity Scratch resistance Rainproof cleaning agent Resistance Chemical resistance Weatherability Shapeability Salt water splashing overall Performance 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 5 8.6 4 Good No 6 0.5 6H 5 5 5 5 8.5 4 Good No 7 0.4 5H 5 5 5 5 8.4 5 Good No 8 0.3 5H 5 4 5 5 8.5 5 Good No 9 0.5 6H 5 5 5 5 8.4 5 Good No 10 0.3 5H 5 5 5 5 8.6 5 Good No 11 0.6 5H 5 4 5 5 8.5 5 Good No 12 0.8 5H 5 5 5 5 8.4 5 Good No 13 0.6 5H 5 4 5 5 8.5 5 Good No 14 0.5 6H 5 5 5 5 8.3 5 Good No 15 0.8 5H 4 5 5 4 8.2 4 Good No 16 0.5 5H 5 5 5 5 8.5 5 Good No 17 0.6 5H 5 5 5 5 8.3 5 Good No 18 0.4 6H 5 5 5 5 8.4 5 Good No 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 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 1296566 Table 3-1 Comparative Examples Chemical Conversion Coatings, Clear Coatings Olefin Wax/No Coating Material Coating Weight (mg/m2) Type Thickness (μm) Wax Quantity (pbw) Particle Size 26 No One A-1 2 - ~ 27 No One A-2 2 ~ One 28 Yes Chromate 10 A-1 2 2 2.5 29 is chromate 30 A-1 2 2 2.5 30 is chromate 10 Polyacetate / 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 amino decane 10 polyester / melamine 2 2 2.5 35 is amino dream burning 10 vinegar / Melamine 2 5 2.5 36 is amino decane 10 B-1 2 2 2.5 37 is amino decane 10 B-2 2 2 2.5

Table 3-2 Comparison of sample coating properties The release of furfural and hexavalent chromium Note coating Scratch resistance Rainproof cleaner Tolerance to chemical resistance and formability Salt water splashing overall Performance 26 - ~ -- - ~ Poor or poor adhesion 27 - One ~ One - One - - 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 is 30 2 3H 3 3 1 2 9.3 3 Poor is 31 1.8 3H 2 3 1 2 9.5 3 Poor is 32 2.4 3H 3 3 1 2 9.7 3 Poor is 33 3.1 4H 2 3 1 1 9.5 4 Poor is 34 0.5 3H 2 3 1 2 9.5 3 Poor is 35 0.6 3H 2 3 1 1 9.4 4 Poor is 36 0.4 3H 5 5 5 5 9.8 5 Bad no 37 0.3 6H 5 5 5 5 9.4 5 Poor pinhole Homogenization 18 1296566 The following method was used to evaluate the coating (1) coating clarity. The color state of the coating was measured by a CR-300 color difference meter (manufactured by Minolta Co., Ltd.) as The color difference Ab value between the steel sheet product baked at a sheet temperature of 193 degrees and the transparent coated stainless steel sheet. Here, the higher Ab represents a higher yellowness. (2) Scratch resistance

The test samples were 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 sample was subjected to a three-month environmental exposure test, and the degree of rain marks formed on the coating was evaluated. 15 2 1 No traces are visible. Traces of weak traces are quite noticeable. Severe traces are produced. (Qualified) (Qualified) (Failed) (Failed) (Failed) (4) Detergent tolerance test sample at 40 The temperature was then immersed in Magiclean (a cleaning agent manufactured by Kao 20 Corporation) for 72 hours, after which the condition of the coating was examined and evaluated. 5: No traces 4: Visible traces 3: Traces are quite obvious (qualified) (passed) (failed) 19 1296566 (failed) (failed) 2: leaves a serious trace 1: sparse (5) Chemical resistance After dropping 2 ML of 5% sulfuric acid and 5% NaOH into the test sample, a steroid was placed on the sample, and the sample was left for 16 hours. The state of the coating is then observed and rated.

10 5 : No traces (qualified) 4 : Visible traces (qualified) 3 ·· Traces are quite obvious (failed) 2 : Significant traces are left (failed) 1 : Peeling (unqualified) (6) The gloss maintenance after 1000 hours was evaluated by a sunlight climatometer (sw〇M) test. 15 5 : 80 to 100% gloss maintenance (qualified)

4 : 60 to 80% gloss maintenance (pass) 3 : 40 to 60% gloss maintenance (failed) 2 : 20 to 40% gloss maintenance (failed) 1 : 0 to 20% gloss maintenance Degree (failed) 20 (7) Erichsen value

The Erichsen value was evaluated according to JIS Z2247. Since the Erichsen value of 9.3 mm is obtained when graphite grease is used under SUS430 stainless steel, a value higher than this value is considered acceptable. (8) Salt-proof splashing 20 ^ 296566 The household coating was inspected, and a salt-proof splash test was carried out for 500 hours according to the method described in JIS Xu), and the peeling process of the coating was examined and evaluated 371. Wait. Also inflamed eye 4 2 less than 5% of the degree of peeling (qualified) 5 to 10% of the degree of peeling (qualified) 10 to 15% of the degree of peeling (failed) 15 to 20% of the degree of peeling (failed) 20% Or higher degree of exfoliation (not inconsistent), as shown in the above description and examples, the present invention provides a non-release of furfural

Transparent coated stainless steel sheet that is excellent in coating clarity, scratch resistance, rain resistance, detergent resistance, chemical resistance, and weather resistance in 1〇 or hexavalent chromium . Further, by adding a weight ratio of 固体·25 to 5 polyolefin wax solid components in a weight ratio of the solid content of each of the thermosetting resins, a transparent coating having excellent lubrication can be obtained. The non-rust steel sheet has better formability than the stainless steel sheet coated with the oil-based lubricant. In contrast, in the comparative example, the peek of the clear coating did not perform well under the lack of chemical conversion treatment. The chromate conversion coated stainless steel sheet produces a yellow hue and contains hexavalent chromium, making it less environmentally friendly. Furthermore, steel sheets coated with polyester/melamine coatings in the past have not performed well in scratch resistance, rain resistance, detergent resistance, chemical resistance, and weather resistance, and may release formaldehyde. . In the case where the acrylic resin in the thermosetting resin has an average molecular weight outside the range of 3,000 to 5 Å, or a glass transition point exceeding 30 to 90 degrees, the transparent coating does not Qiangang 21 1296566 steel sheet has several disadvantages, including poor scratch resistance and poor manufacturability. The present invention provides an environmentally friendly transparent coating which is excellent in coating clarity, weather resistance, rain resistance, scratch resistance, detergent resistance, and chemical resistance without furfural and chromate. Covered with stainless steel sheets. The transparent coated stainless steel sheet is suitable for use in household electrical equipment and can be used as a building material such as internal surface treatment materials and external surface treatment materials.

Simple description of L pattern 3 (none) [Description of main component symbols] (none)

twenty two

Claims (1)

1296566 X. Patent application scope: 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 is composed of a chemical conversion coating comprising aminodecane and/or epoxy decane, α The chemical conversion coating layer has a coating weight of 2 to 50 mg/m 2 , and the top layer is composed of a transparent coating layer containing a thermosetting resin, and the thermosetting resin includes a pressure-sensitive functional group. The resin is used as a main component and a blocked isocyanate compound for crosslinking and curing the acrylic resin, the acrylic resin having a glass transition point of 30 to 90 degrees and a number average molecule of 3,000 to 50,000 Weight, and the clear coating has a thickness of from 1 to 10 microns. 2. The transparent coated stainless steel sheet according to claim 1, wherein the clear coating has 0.25 to 5 solid components of polyolefin wax in a weight ratio of solid components per 100 thermosetting resins. Weight ratio. 3. A transparent coated stainless steel sheet as claimed in claim 2, wherein the polyolefin wax has a particle diameter of between 0.1 and 7 microns. twenty three