JP6880299B2 - Manufacturing method of coated plated steel sheet and coated plated steel sheet - Google Patents
Manufacturing method of coated plated steel sheet and coated plated steel sheet Download PDFInfo
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- JP6880299B2 JP6880299B2 JP2020166036A JP2020166036A JP6880299B2 JP 6880299 B2 JP6880299 B2 JP 6880299B2 JP 2020166036 A JP2020166036 A JP 2020166036A JP 2020166036 A JP2020166036 A JP 2020166036A JP 6880299 B2 JP6880299 B2 JP 6880299B2
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- steel sheet
- protective layer
- plated steel
- plating layer
- mass
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- 229910000831 Steel Inorganic materials 0.000 title claims description 97
- 239000010959 steel Substances 0.000 title claims description 97
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 239000010410 layer Substances 0.000 claims description 146
- 238000007747 plating Methods 0.000 claims description 143
- 239000011241 protective layer Substances 0.000 claims description 118
- 239000003795 chemical substances by application Substances 0.000 claims description 72
- 238000006243 chemical reaction Methods 0.000 claims description 62
- 229920002803 thermoplastic polyurethane Polymers 0.000 claims description 62
- 239000000126 substance Substances 0.000 claims description 55
- 230000009477 glass transition Effects 0.000 claims description 34
- 239000003431 cross linking reagent Substances 0.000 claims description 27
- 239000010954 inorganic particle Substances 0.000 claims description 26
- 229910052782 aluminium Inorganic materials 0.000 claims description 19
- 239000000049 pigment Substances 0.000 claims description 19
- 229910052725 zinc Inorganic materials 0.000 claims description 17
- 239000002253 acid Substances 0.000 claims description 13
- 229910052749 magnesium Inorganic materials 0.000 claims description 13
- 239000012463 white pigment Substances 0.000 claims description 11
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 8
- 238000004132 cross linking Methods 0.000 claims description 7
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 6
- 229910001335 Galvanized steel Inorganic materials 0.000 claims description 5
- 125000000524 functional group Chemical group 0.000 claims description 5
- 239000008397 galvanized steel Substances 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 4
- 239000012948 isocyanate Substances 0.000 claims description 3
- 150000002513 isocyanates Chemical class 0.000 claims description 3
- IMSODMZESSGVBE-UHFFFAOYSA-N 2-Oxazoline Chemical compound C1CN=CO1 IMSODMZESSGVBE-UHFFFAOYSA-N 0.000 claims description 2
- 239000004593 Epoxy Substances 0.000 claims description 2
- 150000001718 carbodiimides Chemical class 0.000 claims description 2
- 150000003961 organosilicon compounds Chemical class 0.000 claims description 2
- 239000011777 magnesium Substances 0.000 description 34
- 230000007797 corrosion Effects 0.000 description 22
- 238000005260 corrosion Methods 0.000 description 22
- 239000011701 zinc Substances 0.000 description 22
- 239000011347 resin Substances 0.000 description 20
- 229920005989 resin Polymers 0.000 description 20
- 239000011651 chromium Substances 0.000 description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 15
- 239000000047 product Substances 0.000 description 14
- 229910052804 chromium Inorganic materials 0.000 description 13
- 238000000034 method Methods 0.000 description 13
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 13
- 229910007981 Si-Mg Inorganic materials 0.000 description 12
- 229910008316 Si—Mg Inorganic materials 0.000 description 12
- 230000008859 change Effects 0.000 description 12
- 239000011575 calcium Substances 0.000 description 11
- 229910007570 Zn-Al Inorganic materials 0.000 description 10
- 239000002932 luster Substances 0.000 description 10
- 230000015572 biosynthetic process Effects 0.000 description 9
- 229910052791 calcium Inorganic materials 0.000 description 8
- 229910052759 nickel Inorganic materials 0.000 description 8
- 239000002245 particle Substances 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 7
- 239000002184 metal Substances 0.000 description 7
- 229910052712 strontium Inorganic materials 0.000 description 7
- 238000000576 coating method Methods 0.000 description 6
- 238000001723 curing Methods 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 229920000178 Acrylic resin Polymers 0.000 description 5
- 239000004925 Acrylic resin Substances 0.000 description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 235000011007 phosphoric acid Nutrition 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 4
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 4
- 230000009471 action Effects 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 150000003016 phosphoric acids Chemical class 0.000 description 4
- 150000003839 salts Chemical class 0.000 description 4
- 229910052727 yttrium Inorganic materials 0.000 description 4
- 229910052684 Cerium Inorganic materials 0.000 description 3
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 3
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 3
- 239000003513 alkali Substances 0.000 description 3
- 239000006229 carbon black Substances 0.000 description 3
- 239000000470 constituent Substances 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 150000004679 hydroxides Chemical class 0.000 description 3
- 239000003112 inhibitor Substances 0.000 description 3
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 3
- 229910052746 lanthanum Inorganic materials 0.000 description 3
- 229910052748 manganese Inorganic materials 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- -1 phosphoric acid compound Chemical class 0.000 description 3
- 229920000728 polyester Polymers 0.000 description 3
- 229910052726 zirconium Inorganic materials 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 2
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 229910052788 barium Inorganic materials 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- UCNNJGDEJXIUCC-UHFFFAOYSA-L hydroxy(oxo)iron;iron Chemical compound [Fe].O[Fe]=O.O[Fe]=O UCNNJGDEJXIUCC-UHFFFAOYSA-L 0.000 description 2
- 229910052745 lead Inorganic materials 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 239000011146 organic particle Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 230000003449 preventive effect Effects 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- 230000037303 wrinkles Effects 0.000 description 2
- 239000011787 zinc oxide Substances 0.000 description 2
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- PMJNEQWWZRSFCE-UHFFFAOYSA-N 3-ethoxy-3-oxo-2-(thiophen-2-ylmethyl)propanoic acid Chemical compound CCOC(=O)C(C(O)=O)CC1=CC=CS1 PMJNEQWWZRSFCE-UHFFFAOYSA-N 0.000 description 1
- 241001163841 Albugo ipomoeae-panduratae Species 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- IMQLKJBTEOYOSI-GPIVLXJGSA-N Inositol-hexakisphosphate Chemical compound OP(O)(=O)O[C@H]1[C@H](OP(O)(O)=O)[C@@H](OP(O)(O)=O)[C@H](OP(O)(O)=O)[C@H](OP(O)(O)=O)[C@@H]1OP(O)(O)=O IMQLKJBTEOYOSI-GPIVLXJGSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- UEZVMMHDMIWARA-UHFFFAOYSA-N Metaphosphoric acid Chemical compound OP(=O)=O UEZVMMHDMIWARA-UHFFFAOYSA-N 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- ABLZXFCXXLZCGV-UHFFFAOYSA-N Phosphorous acid Chemical class OP(O)=O ABLZXFCXXLZCGV-UHFFFAOYSA-N 0.000 description 1
- IMQLKJBTEOYOSI-UHFFFAOYSA-N Phytic acid Natural products OP(O)(=O)OC1C(OP(O)(O)=O)C(OP(O)(O)=O)C(OP(O)(O)=O)C(OP(O)(O)=O)C1OP(O)(O)=O IMQLKJBTEOYOSI-UHFFFAOYSA-N 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 239000006087 Silane Coupling Agent Substances 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- YDONNITUKPKTIG-UHFFFAOYSA-N [Nitrilotris(methylene)]trisphosphonic acid Chemical compound OP(O)(=O)CN(CP(O)(O)=O)CP(O)(O)=O YDONNITUKPKTIG-UHFFFAOYSA-N 0.000 description 1
- YDHWWBZFRZWVHO-UHFFFAOYSA-N [hydroxy(phosphonooxy)phosphoryl] phosphono hydrogen phosphate Chemical compound OP(O)(=O)OP(O)(=O)OP(O)(=O)OP(O)(O)=O YDHWWBZFRZWVHO-UHFFFAOYSA-N 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 150000001408 amides Chemical class 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 125000003277 amino group Chemical group 0.000 description 1
- 229920003180 amino resin Polymers 0.000 description 1
- JOSWYUNQBRPBDN-UHFFFAOYSA-P ammonium dichromate Chemical compound [NH4+].[NH4+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O JOSWYUNQBRPBDN-UHFFFAOYSA-P 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 description 1
- 229910001430 chromium ion Inorganic materials 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- XPPKVPWEQAFLFU-UHFFFAOYSA-N diphosphoric acid Chemical compound OP(O)(=O)OP(O)(O)=O XPPKVPWEQAFLFU-UHFFFAOYSA-N 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- DUYCTCQXNHFCSJ-UHFFFAOYSA-N dtpmp Chemical compound OP(=O)(O)CN(CP(O)(O)=O)CCN(CP(O)(=O)O)CCN(CP(O)(O)=O)CP(O)(O)=O DUYCTCQXNHFCSJ-UHFFFAOYSA-N 0.000 description 1
- NFDRPXJGHKJRLJ-UHFFFAOYSA-N edtmp Chemical compound OP(O)(=O)CN(CP(O)(O)=O)CCN(CP(O)(O)=O)CP(O)(O)=O NFDRPXJGHKJRLJ-UHFFFAOYSA-N 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 239000003995 emulsifying agent Substances 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 239000005010 epoxy-amino resin Substances 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 125000003055 glycidyl group Chemical group C(C1CO1)* 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 229910000398 iron phosphate Inorganic materials 0.000 description 1
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 150000002602 lanthanoids Chemical class 0.000 description 1
- 238000007561 laser diffraction method Methods 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- RPQRDASANLAFCM-UHFFFAOYSA-N oxiran-2-ylmethyl prop-2-enoate Chemical compound C=CC(=O)OCC1CO1 RPQRDASANLAFCM-UHFFFAOYSA-N 0.000 description 1
- 229940068041 phytic acid Drugs 0.000 description 1
- 239000000467 phytic acid Substances 0.000 description 1
- 235000002949 phytic acid Nutrition 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920005906 polyester polyol Polymers 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 229940005657 pyrophosphoric acid Drugs 0.000 description 1
- 229910052705 radium Inorganic materials 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- 238000000790 scattering method Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- GQJPVGNFTLBCIQ-UHFFFAOYSA-L sodium;zirconium(4+);carbonate Chemical compound [Na+].[Zr+4].[O-]C([O-])=O GQJPVGNFTLBCIQ-UHFFFAOYSA-L 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- JBQYATWDVHIOAR-UHFFFAOYSA-N tellanylidenegermanium Chemical compound [Te]=[Ge] JBQYATWDVHIOAR-UHFFFAOYSA-N 0.000 description 1
- UNXRWKVEANCORM-UHFFFAOYSA-N triphosphoric acid Chemical compound OP(O)(=O)OP(O)(=O)OP(O)(O)=O UNXRWKVEANCORM-UHFFFAOYSA-N 0.000 description 1
- 229940048102 triphosphoric acid Drugs 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LRXTYHSAJDENHV-UHFFFAOYSA-H zinc phosphate Chemical compound [Zn+2].[Zn+2].[Zn+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LRXTYHSAJDENHV-UHFFFAOYSA-H 0.000 description 1
- 229910000165 zinc phosphate Inorganic materials 0.000 description 1
- 150000003755 zirconium compounds Chemical class 0.000 description 1
Landscapes
- Application Of Or Painting With Fluid Materials (AREA)
- Laminated Bodies (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
Description
本発明は、被覆めっき鋼板及び被覆めっき鋼板の製造方法に関し、詳しくは、Ａｌ、Ｚｎ、及びＭｇを含有するめっき層を備えるめっき鋼板に保護層が設けられた被覆めっき鋼板及びその製造方法に関する。 The present invention relates to a coated plated steel sheet and a method for producing a coated plated steel sheet, and more particularly to a coated plated steel sheet in which a protective layer is provided on a plated steel sheet having a plating layer containing Al, Zn, and Mg, and a method for producing the same.
建材、自動車用の材料、家電製品用の材料等の用途に、ＺｎとＡｌとを含有するめっき層を備えるめっき鋼板（以下、Ｚｎ−Ａｌ系めっき鋼板という）が広く利用されている。なかでもガルバリウム鋼板（登録商標）に代表される高アルミニウム含有量（例えば２５〜７５質量％）のＺｎ−Ａｌ系めっき鋼板は、耐食性が優れ、需要は大きい。 Plated steel sheets having a plating layer containing Zn and Al (hereinafter referred to as Zn-Al-based plated steel sheets) are widely used for applications such as building materials, materials for automobiles, and materials for home appliances. Among them, Zn—Al-based plated steel sheets having a high aluminum content (for example, 25 to 75% by mass) represented by Galvalume steel sheet (registered trademark) have excellent corrosion resistance and are in great demand.
近年では、更なる耐食性の向上の要求に対応するため、めっき層中にＭｇが添加されたＺｎ−Ａｌ系めっき鋼板（以下、Ｍｇ含有Ｚｎ−Ａｌ系めっき鋼板という）が提案されている（特許文献１参照）。 In recent years, in order to meet the demand for further improvement of corrosion resistance, a Zn-Al-based plated steel sheet in which Mg is added to the plating layer (hereinafter referred to as Mg-containing Zn-Al-based plated steel sheet) has been proposed (patented). Reference 1).
Ｍｇ含有Ｚｎ−Ａｌ系めっき鋼板においては、経時的に、めっき層に含有されるＺｎ又はＡｌの不定比の酸化物又は水酸化物が生成することがある。このような不定比の酸化物又は水酸化物が生成されると、Ｍｇ含有Ｚｎ−Ａｌ系めっき鋼板の表面に黒変が生じることがある。 In the Mg-containing Zn—Al-based plated steel sheet, oxides or hydroxides having an indefinite ratio of Zn or Al contained in the plating layer may be generated over time. When such an oxide or hydroxide having an indefinite ratio is generated, blackening may occur on the surface of the Mg-containing Zn—Al galvanized steel sheet.
Ｍｇ含有Ｚｎ−Ａｌ系めっき鋼板の表面に経時的に黒変が生じても、Ｍｇ含有Ｚｎ−Ａｌ系めっき鋼板の耐食性には影響を及ぼさない。しかし、例えば、塗装を施さずにＭｇ含有Ｚｎ−Ａｌ系めっき鋼板を使用する場合には、Ｍｇ含有Ｚｎ−Ａｌ系めっき鋼板の外観が変化してしまうという問題があった。 Even if the surface of the Mg-containing Zn-Al-based plated steel sheet turns black over time, it does not affect the corrosion resistance of the Mg-containing Zn-Al-based plated steel sheet. However, for example, when the Mg-containing Zn-Al-based plated steel sheet is used without coating, there is a problem that the appearance of the Mg-containing Zn-Al-based plated steel sheet changes.
本発明の目的は、Ａｌ、Ｚｎ、及びＭｇを含有するめっき層を備え、表面外観の変化が抑制された被覆めっき鋼板及びその製造方法を提供することである。 An object of the present invention is to provide a coated plated steel sheet having a plating layer containing Al, Zn, and Mg and suppressing a change in surface appearance, and a method for producing the same.
本発明の一実施形態に係る被覆めっき鋼板は、鋼板と、めっき層と、保護層と、をこの順に積層して備え、前記めっき層は、Ａｌ、Ｚｎ、及びＭｇを含有し、前記保護層は、ウレタン樹脂を含有する化成処理剤から形成され、前記ウレタン樹脂のガラス転移温度は、４０℃以上である。 The coated plated steel sheet according to the embodiment of the present invention includes a steel sheet, a plating layer, and a protective layer laminated in this order, and the plating layer contains Al, Zn, and Mg, and the protective layer is provided. Is formed from a chemical conversion treatment agent containing a urethane resin, and the glass transition temperature of the urethane resin is 40 ° C. or higher.
本発明の一実施形態に係る前記被覆めっき鋼板の製造方法は、前記化成処理剤を前記めっき層に塗布し、７０℃以上１２０℃以下の温度で３秒以上１０秒以下加熱することで前記保護層を形成する工程を含む。 In the method for producing a coated plated steel sheet according to an embodiment of the present invention, the chemical conversion treatment agent is applied to the plating layer and heated at a temperature of 70 ° C. or higher and 120 ° C. or lower for 3 seconds or longer and 10 seconds or shorter to protect the plating layer. Including the step of forming a layer.
本発明によれば、Ａｌ、Ｚｎ、及びＭｇを含有するめっき層を備え、表面外観の変化が抑制された被覆めっき鋼板を得ることができる。 According to the present invention, it is possible to obtain a coated plated steel sheet provided with a plating layer containing Al, Zn, and Mg and in which changes in surface appearance are suppressed.
以下、本発明を実施するための形態を説明する。 Hereinafter, modes for carrying out the present invention will be described.
本実施形態に係る被覆めっき鋼板は、鋼板と、めっき層と、保護層と、をこの順に積層して備える。めっき層は、Ａｌ、Ｚｎ、及びＭｇを含有する。保護層は、ウレタン樹脂を含有する化成処理剤から形成され、前記ウレタン樹脂のガラス転移温度は、４０℃以上である。めっき層がＡｌ、Ｚｎ、及びＭｇを含有することにより、被覆めっき鋼板は、高い耐食性を有することができる。さらに、保護層が、ウレタン樹脂を含有する化成処理剤から形成されることで、保護層の腐食因子に対する遮蔽性を向上させて、めっき層の黒変を抑制することができる。また、ウレタン樹脂のガラス転移温度が４０℃以上であることで、被覆めっき鋼板の表面外観の変化が抑制される。めっき層を備えるめっき鋼板において、経時的にめっき層の表面に黒変が生じることがある。このようなめっき層の黒変は、Ｍｇを含有するめっき層において特に生じやすい。めっき層の表面に黒変が生じるメカニズムは完全には解明されていないが、めっき層に含有されるＺｎ又はＡｌの不定比の酸化物又は水酸化物が生成することが一因であると考えられる。このような酸化物又は水酸化物は、めっき層が水、水蒸気、酸素等に暴露されることによって生じる。本実施形態では、めっき層上に保護層が積層されているため、めっき層が水、水蒸気、酸素等の腐食因子に直接さらされにくくなる。また、本実施形態では、保護層が、ガラス転移温度が４０℃以上であるウレタン樹脂を含有する化成処理剤から形成されているため、保護層は腐食因子の遮蔽性に優れる。このため、例えば高温多湿の環境下においても、めっき層の表面に黒変が生じにくくなり、被覆めっき鋼板の表面外観の変化を抑制することができる。 The coated plated steel sheet according to the present embodiment includes a steel sheet, a plated layer, and a protective layer laminated in this order. The plating layer contains Al, Zn, and Mg. The protective layer is formed from a chemical conversion treatment agent containing a urethane resin, and the glass transition temperature of the urethane resin is 40 ° C. or higher. Since the plating layer contains Al, Zn, and Mg, the coated plated steel sheet can have high corrosion resistance. Further, since the protective layer is formed from a chemical conversion treatment agent containing a urethane resin, it is possible to improve the shielding property of the protective layer against corrosive factors and suppress blackening of the plating layer. Further, when the glass transition temperature of the urethane resin is 40 ° C. or higher, the change in the surface appearance of the coated plated steel sheet is suppressed. In a plated steel sheet provided with a plating layer, blackening may occur on the surface of the plating layer over time. Such blackening of the plating layer is particularly likely to occur in the plating layer containing Mg. The mechanism by which blackening occurs on the surface of the plating layer has not been completely elucidated, but it is thought that this is partly due to the formation of oxides or hydroxides with an indefinite ratio of Zn or Al contained in the plating layer. Be done. Such oxides or hydroxides are produced when the plating layer is exposed to water, water vapor, oxygen and the like. In the present embodiment, since the protective layer is laminated on the plating layer, the plating layer is less likely to be directly exposed to corrosive factors such as water, water vapor, and oxygen. Further, in the present embodiment, since the protective layer is formed of a chemical conversion treatment agent containing a urethane resin having a glass transition temperature of 40 ° C. or higher, the protective layer is excellent in shielding properties of corrosive factors. Therefore, for example, even in a high temperature and high humidity environment, blackening is less likely to occur on the surface of the plated layer, and changes in the surface appearance of the coated plated steel sheet can be suppressed.
被覆めっき鋼板を構成する各層及び材料について詳細に説明する。 Each layer and material constituting the coated plated steel sheet will be described in detail.
鋼板としては、例えば薄鋼板、厚鋼板等の種々の部材が挙げられる。 Examples of the steel plate include various members such as a thin steel plate and a thick steel plate.
［めっき層］
めっき層は、例えば溶融めっき浴に鋼板を浸漬させる等の公知の手段で形成される。
[Plating layer]
The plating layer is formed by a known means such as immersing a steel plate in a hot-dip plating bath.
めっき層は、アルミニウム（Ａｌ）、亜鉛（Ｚｎ）、及びマグネシウム（Ｍｇ）を含有する。めっき層がアルミニウムＡｌ及び亜鉛Ｚｎを含有すると、めっき層の表面は、薄いアルミニウムの酸化皮膜によって覆われる。この酸化皮膜の保護作用によって、特にめっき層の表面の耐食性が向上する。さらに、亜鉛による犠牲防食作用により被覆めっき鋼板の切断端面におけるエッジクリープが抑制される。このため、被覆めっき鋼板に高い耐食性が付与される。さらに、めっき層がＺｎよりも卑な金属であるＭｇを含有することで、めっき層の犠牲防食作用が強化され被覆めっき鋼板の耐食性がより向上する。 The plating layer contains aluminum (Al), zinc (Zn), and magnesium (Mg). When the plating layer contains aluminum Al and zinc Zn, the surface of the plating layer is covered with a thin aluminum oxide film. The protective action of this oxide film improves the corrosion resistance of the surface of the plating layer in particular. Further, the sacrificial anticorrosion action of zinc suppresses edge creep at the cut end face of the coated plated steel sheet. Therefore, high corrosion resistance is imparted to the coated plated steel sheet. Further, since the plating layer contains Mg, which is a metal lower than Zn, the sacrificial anticorrosion action of the plating layer is strengthened and the corrosion resistance of the coated plated steel sheet is further improved.
めっき層の、Ａｌ含有量は１質量％以上７５質量％以下であることが好ましい。Ａｌ含有量が１質量％以上であれば、めっき層の表面における耐食性が確保されるため、被覆めっき鋼板は、高い耐食性を有しうる。Ａｌ含有量が７５質量％以下であればＺｎによる犠牲防食効果が充分に発揮されるとともにめっき層の硬質化が抑制されて、被覆めっき鋼板の折曲加工性を高くすることができる。Ａｌ含有量は、４５質量％以上であればより好ましく、また６５質量％以下であることもより好ましく、４５質量％以上６５質量％以下であれば更に好ましい。 The Al content of the plating layer is preferably 1% by mass or more and 75% by mass or less. When the Al content is 1% by mass or more, the corrosion resistance on the surface of the plated layer is ensured, so that the coated plated steel sheet can have high corrosion resistance. When the Al content is 75% by mass or less, the sacrificial anticorrosion effect of Zn is sufficiently exhibited, the hardening of the plating layer is suppressed, and the bendability of the coated plated steel sheet can be improved. The Al content is more preferably 45% by mass or more, more preferably 65% by mass or less, and further preferably 45% by mass or more and 65% by mass or less.
めっき層の、Ｍｇ含有量は０質量％を超えて６．０質量％以下であることが好ましい。Ｍｇ含有量が０．１質量％以上であるとＭｇの添加による効果が明瞭に現れる。Ｍｇ含有量が０．５質量％以上であると、耐食性向上効果が安定して得られるので、より好ましい。Ｍｇ含有量は、５．０質量％以下であればより好ましく、３．０質量％以下であれば更
に好ましい。Ｍｇ含有量は、１．０質量％以上３．０質量％以下であれば特に好ましい。
The Mg content of the plating layer is preferably more than 0% by mass and 6.0% by mass or less. When the Mg content is 0.1% by mass or more, the effect of adding Mg clearly appears. When the Mg content is 0.5% by mass or more, the effect of improving corrosion resistance can be stably obtained, which is more preferable. The Mg content is more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less. The Mg content is particularly preferably 1.0% by mass or more and 3.0% by mass or less.
めっき層は、Ｓｉ、Ｎｉ、Ｃｅ、Ｃｒ、Ｆｅ、Ｃａ、Ｓｒ及び希土類から選択される一種以上の元素を含有してもよい。めっき層が、Ｎｉ及びＣｒ；Ｃａ、Ｓｒなどのアルカリ土類元素；並びにＹ、Ｌａ、Ｃｅなどの希土類からなる群から選択される、一種以上の元素を含有する場合、めっき層のアルミニウムに起因する保護作用と、亜鉛に起因する犠牲防食作用とがともに強化されることで、被覆めっき鋼板の耐食性は更に向上する。 The plating layer may contain one or more elements selected from Si, Ni, Ce, Cr, Fe, Ca, Sr and rare earths. When the plating layer contains one or more elements selected from the group consisting of alkaline earth elements such as Ni and Cr; Ca and Sr; and rare earth elements such as Y, La and Ce, it is caused by the aluminum of the plating layer. By strengthening both the protective action and the sacrificial anticorrosion action caused by zinc, the corrosion resistance of the coated plated steel sheet is further improved.
特に、めっき層は、ＮｉとＣｒとのうち、１種以上を含有することが好ましい。めっき層がＮｉを含有する場合、めっき層のＮｉ含有量は、０質量％を超えて１質量％以下であることが好ましい。Ｎｉ含有量は、０．０１質量％以上０．５質量％以下であればより好ましい。めっき層がＣｒを含有する場合、めっき層中のＣｒ含有量は、０質量％を超えて１質量％以下であることが好ましい。Ｃｒ含有量は、０．０１質量％以上０．５質量％以下であればより好ましい。これらの場合、被覆めっき鋼板の耐食性が向上する。耐食性向上のためには、例えばＮｉ及びＣｒが、鋼板とめっき層との界面付近に存在し、あるいはめっき層内のＮｉ及びＣｒの濃度分布が鋼板に近い位置ほど濃度が高くなるような偏りを有していることが好ましい。 In particular, the plating layer preferably contains at least one of Ni and Cr. When the plating layer contains Ni, the Ni content of the plating layer is preferably more than 0% by mass and 1% by mass or less. The Ni content is more preferably 0.01% by mass or more and 0.5% by mass or less. When the plating layer contains Cr, the Cr content in the plating layer is preferably more than 0% by mass and 1% by mass or less. The Cr content is more preferably 0.01% by mass or more and 0.5% by mass or less. In these cases, the corrosion resistance of the coated plated steel sheet is improved. In order to improve corrosion resistance, for example, Ni and Cr are present near the interface between the steel sheet and the plating layer, or the concentration distribution of Ni and Cr in the plating layer is biased so that the concentration becomes higher as it is closer to the steel sheet. It is preferable to have it.
めっき層は、Ｓｉを含有してもよい。めっき層がＳｉを含有すると、被覆めっき鋼板の機械的加工性を向上させることができる。めっき層のＳｉ含有量は、Ａｌ含有量に対して０．５質量％以上１０質量％以下であることが好ましい。ＳｉのＡｌに対する含有量が０．５質量％以上であるとめっき層中のＡｌと鋼板との過度の合金化が充分に抑制される。ＳｉのＡｌに対する含有量が１０質量％より多くなるとＳｉによる作用が飽和するだけでなくめっき層の作製時に溶融めっき浴中にドロスが発生しやすくなってしまう。ＳｉのＡｌに対する含有量は特に１．０質量％以上であることが好ましい。また、ＳｉのＡｌに対する含有量は特に５．０質量％以下であることが好ましい。Ｓｉの含有量が１．０質量％以上５．０質量％以下であれば特に好ましい。 The plating layer may contain Si. When the plating layer contains Si, the mechanical workability of the coated plated steel sheet can be improved. The Si content of the plating layer is preferably 0.5% by mass or more and 10% by mass or less with respect to the Al content. When the content of Si with respect to Al is 0.5% by mass or more, excessive alloying of Al and the steel sheet in the plating layer is sufficiently suppressed. If the content of Si with respect to Al is more than 10% by mass, not only the action of Si is saturated, but also dross is likely to occur in the hot-dip plating bath during the production of the plating layer. The content of Si with respect to Al is particularly preferably 1.0% by mass or more. Further, the content of Si with respect to Al is particularly preferably 5.0% by mass or less. It is particularly preferable that the Si content is 1.0% by mass or more and 5.0% by mass or less.
めっき層がＳｉを含有する場合、めっき層中のＳｉ：Ｍｇの質量比が１００：５０〜１００：３００の範囲内であることが好ましい。この場合、めっき層中のＳｉ−Ｍｇ層の形成が特に促進され、めっき層におけるしわの発生が更に抑制される。このＳｉ：Ｍｇの質量比は、更に１００：７０〜１００：２５０であることが好ましく、更に１００：１００〜１００：２００の範囲内であることが好ましい。 When the plating layer contains Si, the mass ratio of Si: Mg in the plating layer is preferably in the range of 100:50 to 100: 300. In this case, the formation of the Si—Mg layer in the plating layer is particularly promoted, and the generation of wrinkles in the plating layer is further suppressed. The mass ratio of Si: Mg is preferably 100: 70 to 100: 250, and more preferably in the range of 100: 100 to 100: 200.
めっき層がＳｉを含有する場合、めっき層は、０．２体積％以上１５体積％以下のＳｉ−Ｍｇ相を含むことが好ましい。Ｓｉ−Ｍｇ相は、ＳｉとＭｇとの金属間化合物で構成される層であり、めっき層中に分散して存在することができる。めっき層におけるＳｉ−Ｍｇ相の体積割合は、めっき層をその厚み方向に切断した場合の切断面におけるＳｉ−Ｍｇ相の面積割合と等しい。めっき層の切断面におけるＳｉ−Ｍｇ相は、電子顕微鏡観察により明瞭に確認され得る。このため、切断面におけるＳｉ−Ｍｇ相の面積割合を測定することで、めっき層におけるＳｉ−Ｍｇ相の体積割合を間接的に測定することができる。めっき層中のＳｉ−Ｍｇ相の体積割合が高いほど、めっき層におけるしわの発生が抑制される。これは、めっき層の作製時に溶融めっき金属が冷却されることで凝固してめっき層が形成されるプロセスにおいて、溶融めっき金属が完全に凝固する前に、Ｓｉ−Ｍｇ相が溶融めっき金属中で析出し、このＳｉ−Ｍｇ相が溶融めっき金属の流動を抑制するためと考えられる。Ｓｉ−Ｍｇ相の体積割合は０．２体積％以上１０体積％以下であればより好ましく、０．４体積％以上５体積％以下であれば更に好ましい。 When the plating layer contains Si, the plating layer preferably contains a Si—Mg phase of 0.2% by volume or more and 15% by volume or less. The Si-Mg phase is a layer composed of an intermetallic compound of Si and Mg, and can be dispersed in the plating layer. The volume ratio of the Si-Mg phase in the plating layer is equal to the area ratio of the Si-Mg phase on the cut surface when the plating layer is cut in the thickness direction thereof. The Si-Mg phase on the cut surface of the plating layer can be clearly confirmed by electron microscope observation. Therefore, by measuring the area ratio of the Si-Mg phase on the cut surface, the volume ratio of the Si-Mg phase in the plating layer can be indirectly measured. The higher the volume ratio of the Si—Mg phase in the plating layer, the more the generation of wrinkles in the plating layer is suppressed. This is because in the process in which the hot-dip plating metal is cooled during the production of the plating layer to form a plating layer, the Si-Mg phase is contained in the hot-dip plating metal before the hot-dip plating metal is completely solidified. It is considered that this Si-Mg phase precipitates and suppresses the flow of the hot-dip plated metal. The volume ratio of the Si—Mg phase is more preferably 0.2% by volume or more and 10% by volume or less, and further preferably 0.4% by volume or more and 5% by volume or less.
めっき層は、Ｃａ、Ｓｒ、Ｙ、Ｌａ及びＣｅのうち、１種類以上を含有してもよい。めっき層がＣａを含有する場合、めっき層のＣａ含有量は、０質量％を超えて０．５質量％
以下であることが好ましい。Ｃａ含有量は、０．００１質量％以上０．１質量％以下であればより好ましい。めっき層がＳｒを含有する場合、めっき層のＳｒ含有量は、０質量％を超えて０．５質量％以下であることが好ましい。Ｓｒ含有量は、０．００１質量％以上０．１質量％以下であればより好ましい。めっき層がＹを含有する場合、めっき層のＹ含有量は、０質量％を超えて０．５質量％以下であることが好ましい。Ｙ含有量は、０．００１質量％以上０．１質量％以下であればより好ましい。めっき層がＬａを含有する場合、めっき層のＬａ含有量は、０質量％を超えて０．５質量％以下であることが好ましい。Ｌａ含有量は、０．００１質量％以上０．１質量％以下であればより好ましい。めっき層がＣｅを含有する場合、めっき層のＣｅ含有量は、０質量％を超えて０．５質量％以下であることが好ましい。Ｃｅ含有量は、０．００１質量％以上０．１質量％以下であればより好ましい。これらの場合、被覆めっき鋼板の耐食性が向上するとともに、めっき層の表面における欠陥の抑制効果が期待される。
The plating layer may contain one or more of Ca, Sr, Y, La and Ce. When the plating layer contains Ca, the Ca content of the plating layer exceeds 0% by mass and is 0.5% by mass.
The following is preferable. The Ca content is more preferably 0.001% by mass or more and 0.1% by mass or less. When the plating layer contains Sr, the Sr content of the plating layer is preferably more than 0% by mass and 0.5% by mass or less. The Sr content is more preferably 0.001% by mass or more and 0.1% by mass or less. When the plating layer contains Y, the Y content of the plating layer is preferably more than 0% by mass and 0.5% by mass or less. The Y content is more preferably 0.001% by mass or more and 0.1% by mass or less. When the plating layer contains La, the La content of the plating layer is preferably more than 0% by mass and 0.5% by mass or less. The La content is more preferably 0.001% by mass or more and 0.1% by mass or less. When the plating layer contains Ce, the Ce content of the plating layer is preferably more than 0% by mass and 0.5% by mass or less. The Ce content is more preferably 0.001% by mass or more and 0.1% by mass or less. In these cases, the corrosion resistance of the coated plated steel sheet is improved, and the effect of suppressing defects on the surface of the plated layer is expected.
アルカリ土類元素（Ｂｅ、Ｃａ、Ｂａ、Ｒａ）、Ｓｃ、Ｙ、及びランタノイド元素（Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ等）は、Ｓｒと同様の作用を発揮する。めっき層におけるこれらの成分の含有量の総量は、質量比率で１．０質量％以下であることが好ましい。 Alkaline earth elements (Be, Ca, Ba, Ra), Sc, Y, and lanthanoid elements (La, Ce, Pr, Nd, Pm, Sm, Eu, etc.) exert the same effects as Sr. The total content of these components in the plating layer is preferably 1.0% by mass or less in terms of mass ratio.
Ｚｎは、めっき層の構成元素全体のうち、Ｚｎ以外の構成元素を除いた残部を占める。 Zn occupies the balance of all the constituent elements of the plating layer excluding the constituent elements other than Zn.
めっき層は、Ａｌ、Ｚｎ、Ｍｇ、Ｓｉ、Ｎｉ、Ｃｅ、Ｃｒ、Ｆｅ、Ｃａ、Ｓｒ及び希土類以外の元素を含有してもよい。例えば、めっき層は、Ｐｂ、Ｓｎ、Ｃｏ、Ｂ、Ｍｎ及びＣｕからなる群から選択される一種以上の元素を含有してもよい。Ａｌ、Ｚｎ、Ｍｇ、Ｓｉ、Ｎｉ、Ｃｅ、Ｃｒ、Ｆｅ、Ｃａ、Ｓｒ及び希土類以外の元素は、めっき層中にその構成元素として含有していてもよく、鋼板から溶出したり、めっき浴の原料中に不純物として混在したりしてもよい。めっき層におけるＡｌ、Ｚｎ、Ｍｇ、Ｓｉ、Ｎｉ、Ｃｅ、Ｃｒ、Ｆｅ、Ｃａ、Ｓｒ及び希土類以外の元素の総量の割合は、０．１質量％以下であることが好ましい。 The plating layer may contain elements other than Al, Zn, Mg, Si, Ni, Ce, Cr, Fe, Ca, Sr and rare earths. For example, the plating layer may contain one or more elements selected from the group consisting of Pb, Sn, Co, B, Mn and Cu. Elements other than Al, Zn, Mg, Si, Ni, Ce, Cr, Fe, Ca, Sr and rare earth elements may be contained in the plating layer as constituent elements thereof, and may be eluted from the steel sheet or in the plating bath. It may be mixed as an impurity in the raw material. The ratio of the total amount of elements other than Al, Zn, Mg, Si, Ni, Ce, Cr, Fe, Ca, Sr and rare earths in the plating layer is preferably 0.1% by mass or less.
ただし、言うまでもないが、めっき層は、Ｐｂ、Ｃｄ、Ｃｕ、Ｍｎ等の不可避的不純物を含有してもよい。この不可避的不純物の含有量はできるだけ少ない方が好ましく、特にこの不可避的不純物の含有量の合計がめっき層に対して質量比率で１質量％以下であることが好ましい。 However, needless to say, the plating layer may contain unavoidable impurities such as Pb, Cd, Cu, and Mn. The content of the unavoidable impurities is preferably as small as possible, and it is particularly preferable that the total content of the unavoidable impurities is 1% by mass or less in terms of mass ratio with respect to the plating layer.
鋼板とめっき層との間には、例えばＡｌとＣｒとを含有する合金層が介在していてもよい。 An alloy layer containing, for example, Al and Cr may be interposed between the steel sheet and the plating layer.
［保護層］
保護層は、一般に化成処理層とも呼ばれ、めっき層を防食するために形成される層である。保護層は、例えば鋼板にめっき層を作製し、めっき層に化成処理剤を塗布して硬化させることで形成される。なお、本明細書中の説明において、硬化することには、化学反応によって硬化することと、乾燥されることで固化することとが、含まれる。化学反応することには、樹脂のみが化学反応することと、樹脂と樹脂以外の架橋剤、硬化剤等の成分とが化学反応することとが、含まれる。
[Protective layer]
The protective layer is also generally called a chemical conversion treatment layer, and is a layer formed to prevent corrosion of the plating layer. The protective layer is formed, for example, by forming a plating layer on a steel sheet, applying a chemical conversion treatment agent to the plating layer, and curing the plating layer. In the description of the present specification, curing includes curing by a chemical reaction and solidification by drying. The chemical reaction includes a chemical reaction of only the resin and a chemical reaction of the resin and components such as a cross-linking agent and a curing agent other than the resin.
保護層は、ウレタン樹脂を含有する化成処理剤から形成される。保護層が、ウレタン樹脂を含有する化成処理剤から形成されることで、保護層の水、水蒸気、酸素等の腐食因子に対する遮蔽性を向上させて、めっき層の黒変を抑制することができる。 The protective layer is formed from a chemical conversion treatment agent containing a urethane resin. By forming the protective layer from a chemical conversion treatment agent containing a urethane resin, it is possible to improve the shielding property of the protective layer against corrosion factors such as water, water vapor, and oxygen, and suppress blackening of the plating layer. ..
ウレタン樹脂のガラス転移温度は、４０℃以上である。すなわち、保護層は、ガラス転
移温度が４０℃以上であるウレタン樹脂を含有する化成処理剤から形成される。ウレタン樹脂のガラス転移温度が４０℃以上であることで、保護層は水、水蒸気、酸素等の腐食因子の遮蔽性に優れる。このため、例えば高温多湿の環境下においても、めっき層の表面に黒変が生じにくくなり、被覆めっき鋼板の表面外観の変化を抑制することができる。
The glass transition temperature of the urethane resin is 40 ° C. or higher. That is, the protective layer is formed from a chemical conversion treatment agent containing a urethane resin having a glass transition temperature of 40 ° C. or higher. When the glass transition temperature of the urethane resin is 40 ° C. or higher, the protective layer has excellent shielding properties against corrosive factors such as water, water vapor, and oxygen. Therefore, for example, even in a high temperature and high humidity environment, blackening is less likely to occur on the surface of the plated layer, and changes in the surface appearance of the coated plated steel sheet can be suppressed.
化成処理剤に含まれるウレタン樹脂は、ガラス転移温度が４０℃以上であるウレタン樹脂であれば特に限定されないが、水系ウレタン樹脂を用いることが好ましい。ウレタン樹脂として、例えばウレタンディスパーションを用いてもよく、水系ウレタンディスパーションを用いることが好ましい。 The urethane resin contained in the chemical conversion treatment agent is not particularly limited as long as it is a urethane resin having a glass transition temperature of 40 ° C. or higher, but it is preferable to use an aqueous urethane resin. As the urethane resin, for example, urethane dispersion may be used, and it is preferable to use water-based urethane dispersion.
ガラス転移温度が４０℃以上であるウレタン樹脂は、保護層に４０質量％以上含有されることが好ましい。この場合、保護層は、優れた腐食因子に対する遮蔽性を有することができる。ガラス転移温度が４０℃以上であるウレタン樹脂は、保護層に５０質量％以上含有されることがより好ましい。保護層中のガラス転移温度が４０℃以上であるウレタン樹脂の含有量の上限は特に限定されない。 The urethane resin having a glass transition temperature of 40 ° C. or higher is preferably contained in the protective layer in an amount of 40% by mass or more. In this case, the protective layer can have excellent shielding properties against corrosive factors. The urethane resin having a glass transition temperature of 40 ° C. or higher is more preferably contained in the protective layer in an amount of 50% by mass or more. The upper limit of the content of the urethane resin having a glass transition temperature of 40 ° C. or higher in the protective layer is not particularly limited.
ウレタン樹脂の酸価は、１５ｍｇＫＯＨ／ｇ以上であることが好ましい。すなわち、化成処理剤に含まれるガラス転移温度が４０℃以上であるウレタン樹脂の酸価は、１５ｍｇＫＯＨ／ｇ以上であることが好ましい。この場合、化成処理剤から形成される保護層とめっき層との密着性を高めることができる。また，ウレタン樹脂と架橋剤が架橋反応を生じ易くなる。そのため、保護層とめっき層との界面から水、水蒸気、酸素等が侵入することを防ぐことができ、めっき層の黒変を抑制できる。ウレタン樹脂の酸価は、２０ｍｇＫＯＨ以上であることがより好ましい。この場合、保護層とめっき層との密着性をより高めることができる。ウレタン樹脂の酸価の上限は特に限定されないが、例えば５０ｍｇＫＯＨ以下であってよい。 The acid value of the urethane resin is preferably 15 mgKOH / g or more. That is, the acid value of the urethane resin contained in the chemical conversion treatment agent and having a glass transition temperature of 40 ° C. or higher is preferably 15 mgKOH / g or higher. In this case, the adhesion between the protective layer formed from the chemical conversion treatment agent and the plating layer can be improved. In addition, the urethane resin and the cross-linking agent are likely to cause a cross-linking reaction. Therefore, it is possible to prevent water, water vapor, oxygen, etc. from entering from the interface between the protective layer and the plating layer, and it is possible to suppress blackening of the plating layer. The acid value of the urethane resin is more preferably 20 mgKOH or more. In this case, the adhesion between the protective layer and the plating layer can be further improved. The upper limit of the acid value of the urethane resin is not particularly limited, but may be, for example, 50 mgKOH or less.
ウレタン樹脂は、最低造膜温度が５０℃以下であることが好ましい。すなわち、化成処理剤に含まれるガラス転移温度が４０℃以上であるウレタン樹脂は、最低造膜温度が５０℃以下であることが好ましい。最低造膜温度が５０℃以下であるウレタン樹脂を用いることで、化成処理剤から形成される保護層の腐食因子に対する遮蔽性がより向上し、めっき層の黒変が更に抑制される。ウレタン樹脂は、最低造膜温度が４０℃以下であることがより好ましい。ウレタン樹脂の最低造膜温度の下限は特に限定されないが、例えば−５℃以上であることが好ましい。 The urethane resin preferably has a minimum film forming temperature of 50 ° C. or lower. That is, the urethane resin contained in the chemical conversion treatment agent having a glass transition temperature of 40 ° C. or higher preferably has a minimum film formation temperature of 50 ° C. or lower. By using a urethane resin having a minimum film forming temperature of 50 ° C. or lower, the shielding property of the protective layer formed from the chemical conversion treatment agent against corrosive factors is further improved, and blackening of the plating layer is further suppressed. The urethane resin preferably has a minimum film forming temperature of 40 ° C. or lower. The lower limit of the minimum film-forming temperature of the urethane resin is not particularly limited, but is preferably −5 ° C. or higher, for example.
ウレタン樹脂は、熱軟化温度が２００℃以下であることが好ましい。すなわち、化成処理剤に含まれるガラス転移温度が４０℃以上であるウレタン樹脂は、熱軟化温度が２００℃以下であることが好ましい。熱軟化温度が２００℃以下であるウレタン樹脂を用いることで、化成処理剤から形成される保護層の腐食因子に対する遮蔽性がより向上し、めっき層の黒変が更に抑制される。ウレタン樹脂は、熱軟化温度が１８０℃以下であることがより好ましい。ウレタン樹脂の熱軟化温度の下限は特に限定されない。 The urethane resin preferably has a thermal softening temperature of 200 ° C. or lower. That is, the urethane resin contained in the chemical conversion treatment agent having a glass transition temperature of 40 ° C. or higher preferably has a thermal softening temperature of 200 ° C. or lower. By using a urethane resin having a heat softening temperature of 200 ° C. or lower, the shielding property of the protective layer formed from the chemical conversion treatment agent against corrosive factors is further improved, and blackening of the plating layer is further suppressed. The urethane resin preferably has a thermal softening temperature of 180 ° C. or lower. The lower limit of the thermal softening temperature of the urethane resin is not particularly limited.
ウレタン樹脂は、最低造膜温度が５０℃以下であり、かつ熱軟化温度が２００℃以下であることが特に好ましい。最低造膜温度が５０℃以下であり、かつ熱軟化温度が２００℃以下であるウレタン樹脂を用いることで、化成処理剤から形成される保護層の腐食因子に対する遮蔽性が特に向上し、めっき層の黒変が更に抑制される。 It is particularly preferable that the urethane resin has a minimum film forming temperature of 50 ° C. or lower and a heat softening temperature of 200 ° C. or lower. By using a urethane resin having a minimum film forming temperature of 50 ° C. or lower and a thermal softening temperature of 200 ° C. or lower, the shielding property of the protective layer formed from the chemical conversion treatment agent against corrosive factors is particularly improved, and the plating layer is plated. Blackening is further suppressed.
化成処理剤は、ガラス転移温度が４０℃以上であるウレタン樹脂以外の樹脂を含んでもよい。すなわち、化成処理剤から形成される保護層は、ガラス転移温度が４０℃以上であるウレタン樹脂以外の樹脂を含有してもよい。ガラス転移温度が４０℃以上であるウレタン樹脂以外の樹脂は、ガラス転移温度が４０℃未満であるウレタン樹脂と、ウレタン樹脂
以外の樹脂とを含む。ウレタン樹脂以外の樹脂の例は、アクリル樹脂、ポリエステル樹脂、アミド樹脂、エポキシ樹脂、及びアミノ樹脂を含む。
The chemical conversion treatment agent may contain a resin other than the urethane resin having a glass transition temperature of 40 ° C. or higher. That is, the protective layer formed from the chemical conversion treatment agent may contain a resin other than the urethane resin having a glass transition temperature of 40 ° C. or higher. The resin other than the urethane resin having a glass transition temperature of 40 ° C. or higher includes a urethane resin having a glass transition temperature of less than 40 ° C. and a resin other than the urethane resin. Examples of resins other than urethane resins include acrylic resins, polyester resins, amide resins, epoxy resins, and amino resins.
化成処理剤が、ガラス転移温度が４０℃以上であるウレタン樹脂以外の樹脂を含む場合、ガラス転移温度が４０℃以上であるウレタン樹脂以外の樹脂の含有量は、保護層中に５０質量％以下であることが好ましい。この場合、保護層は、腐食因子に対する良好な遮蔽性を有することができる。ガラス転移温度が４０℃以上であるウレタン樹脂以外の樹脂は、保護層中に４０質量％以下で含まれることがより好ましい。ガラス転移温度が４０℃以上であるウレタン樹脂以外の樹脂の含有量の下限は特に限定されず、保護層は、ガラス転移温度が４０℃以上であるウレタン樹脂以外の樹脂を含まなくてもよい。 When the chemical conversion agent contains a resin other than the urethane resin having a glass transition temperature of 40 ° C. or higher, the content of the resin other than the urethane resin having a glass transition temperature of 40 ° C. or higher is 50% by mass or less in the protective layer. Is preferable. In this case, the protective layer can have good shielding properties against corrosive factors. A resin other than the urethane resin having a glass transition temperature of 40 ° C. or higher is more preferably contained in the protective layer in an amount of 40% by mass or less. The lower limit of the content of the resin other than the urethane resin having a glass transition temperature of 40 ° C. or higher is not particularly limited, and the protective layer may not contain a resin other than the urethane resin having a glass transition temperature of 40 ° C. or higher.
化成処理剤は、架橋剤を含有することが好ましい。化成処理剤が架橋剤を含有することで、架橋剤とウレタン樹脂中の官能基とが架橋反応を起こし、これによって化成処理剤から形成される保護層の、腐食因子に対する遮蔽性がより向上する。化成処理剤中の架橋剤の含有量は、樹脂成分の含有量によって適宜調整されうる。 The chemical conversion treatment agent preferably contains a cross-linking agent. When the chemical conversion treatment agent contains a cross-linking agent, the cross-linking agent and the functional groups in the urethane resin undergo a cross-linking reaction, whereby the shielding property of the protective layer formed from the chemical conversion treatment agent against corrosive factors is further improved. .. The content of the cross-linking agent in the chemical conversion treatment agent can be appropriately adjusted depending on the content of the resin component.
架橋剤は、例えば、化成処理剤に０．３質量％以上含有されることが好ましい。この場合、化成処理剤から形成される保護層の腐食因子に対する遮蔽性を向上させることができる。架橋剤は、化成処理剤に０．５質量％以上含有されることがより好ましい。架橋剤の含有量の上限は特に限定されないが、例えば、化成処理剤に２０質量％以下で含有されてよい。 The cross-linking agent is preferably contained in, for example, 0.3% by mass or more in the chemical conversion treatment agent. In this case, the shielding property of the protective layer formed from the chemical conversion treatment agent against corrosive factors can be improved. It is more preferable that the cross-linking agent is contained in the chemical conversion treatment agent in an amount of 0.5% by mass or more. The upper limit of the content of the cross-linking agent is not particularly limited, but for example, it may be contained in the chemical conversion treatment agent in an amount of 20% by mass or less.
化成処理剤に含まれる架橋剤は、化成処理剤に含まれるウレタン樹脂中の官能基と架橋反応を起こすが、化成処理剤に含まれる架橋剤すべてが架橋反応に関与しなくてもよい。すなわち、化成処理剤に含まれる架橋剤は、化成処理剤から形成される保護層中に残存してもよい。 The cross-linking agent contained in the chemical conversion treatment agent causes a cross-linking reaction with the functional groups in the urethane resin contained in the chemical conversion treatment agent, but all the cross-linking agents contained in the chemical conversion treatment agent do not have to be involved in the cross-linking reaction. That is, the cross-linking agent contained in the chemical conversion treatment agent may remain in the protective layer formed from the chemical conversion treatment agent.
架橋剤は、架橋性官能基を有する有機ケイ素化合物、エポキシ系架橋剤、オキサゾリン系架橋剤、カルボジイミド系架橋剤、及びブロックイソシアネート系架橋剤からなる群から選択される少なくとも１種を含むことが好ましい。この場合、化成処理剤中の架橋剤とウレタン樹脂の官能基とが、低温（例えば、常温〜約１００℃）であっても架橋反応を起こしやすい。そのため、化成処理剤から保護層を形成する場合に、高温にする必要がなく、保護層の形成が容易になる。 The cross-linking agent preferably contains at least one selected from the group consisting of an organosilicon compound having a cross-linking functional group, an epoxy-based cross-linking agent, an oxazoline-based cross-linking agent, a carbodiimide-based cross-linking agent, and a blocked isocyanate-based cross-linking agent. .. In this case, the cross-linking agent in the chemical conversion treatment agent and the functional group of the urethane resin are likely to cause a cross-linking reaction even at a low temperature (for example, normal temperature to about 100 ° C.). Therefore, when the protective layer is formed from the chemical conversion treatment agent, it is not necessary to raise the temperature to a high temperature, and the protective layer can be easily formed.
化成処理剤は、例えばクロメート処理剤、３価クロム酸処理剤などのクロムを含有する処理剤；リン酸亜鉛処理剤、リン酸鉄処理剤などのリン酸系の処理剤；コバルト、ニッケル、タングステン、ジルコニウムなどの金属酸化物を単独であるいは複合して含有する酸化物処理剤；腐食を防止するインヒビター成分を含有する処理剤；バインダー成分（有機、無機、有機―無機複合など）とインヒビター成分を複合した処理剤；インヒビター成分と金属酸化物とを複合した処理剤；バインダー成分とシリカやチタニア、ジルコニアなどのゾルとを複合した処理剤；又は上記に例示した処理剤の成分を更に複合した処理剤である。 Chemical treatment agents include, for example, chromium-containing treatment agents such as chromate treatment agents and trivalent chromium acid treatment agents; phosphoric acid-based treatment agents such as zinc phosphate treatment agents and iron phosphate treatment agents; cobalt, nickel, and tungsten. , Oxide treatment agent containing metal oxide such as zirconium alone or in combination; Treatment agent containing inhibitor component to prevent corrosion; Binder component (organic, inorganic, organic-inorganic composite, etc.) and inhibitor component Combined treatment agent; Treatment agent in which an inhibitor component and a metal oxide are combined; Treatment agent in which a binder component and a sol such as silica, titania, or zirconia are combined; It is an agent.
化成処理剤のより好ましい例としては、ジルコニウムを含有する酸化物処理剤、リン酸化合物、及びクロムを含有する処理剤が挙げられる。 More preferred examples of chemical conversion treatment agents include zirconium-containing oxide treatment agents, phosphoric acid compounds, and chromium-containing treatment agents.
ジルコニウムを含有する酸化物処理剤は、例えば、水及び水分散性のポリエステル系ウレタン樹脂と、水分散性アクリル樹脂と、炭酸ジルコニウムナトリウムなどのジルコニウム化合物と、ヒンダードアミン類とを含有する。水分散性のポリエステル系ウレタン樹脂は、例えばポリエステルポリオールと水添型イソシアネートとを反応させるとともにジメ
チロールアルキル酸を共重合させることで自己乳化させることで合成される。このような水分散性のポリエステル系ウレタン樹脂によって、乳化剤を使用することなく保護層に高い耐水性を付与することができるとともに、被覆めっき鋼板の耐食性や耐アルカリ性が向上しうる。
The zirconium-containing oxide treatment agent contains, for example, a water- and water-dispersible polyester urethane resin, a water-dispersible acrylic resin, a zirconium compound such as sodium zirconium carbonate, and hindered amines. The water-dispersible polyester-based urethane resin is synthesized, for example, by reacting a polyester polyol with a hydrogenated isocyanate and self-emulsifying by copolymerizing a dimethylolalkyl acid. Such a water-dispersible polyester urethane resin can impart high water resistance to the protective layer without using an emulsifier, and can improve the corrosion resistance and alkali resistance of the coated galvanized steel sheet.
リン酸化合物としては、特に限定されないが、例えば、オルトリン酸、メタリン酸、ピロリン酸、三リン酸、四リン酸等のリン酸類及びこれらの塩；アミノトリ（メチレンホスホン酸）、１−ヒドロキシエチリデン−１，１−ジホスホン酸、エチレンジアミンテトラ（メチレンホスホン酸）、ジエチレントリアミンペンタ（メチレンホスホン酸）等のホスホン酸類及びこれらの塩；並びにフィチン酸等の有機リン酸類及びこれらの塩等を挙げることができる。塩類のカチオン種としては特に制限されず、例えば、Ｃｕ、Ｃｏ、Ｆｅ、Ｍｎ、Ｓｎ、Ｖ、Ｍｇ、Ｂａ、Ａｌ、Ｃａ、Ｓｒ、Ｎｂ、Ｙ、Ｎｉ、Ｚｎ及びアンモニウム等が挙げられるが、Ａｌ及びアンモニウムであることが好ましい。これらのリン酸化合物は、単独で用いてもよく、２種以上を併用してもよい。 The phosphoric acid compound is not particularly limited, and for example, phosphoric acids such as orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, and tetraphosphoric acid and salts thereof; aminotri (methylenephosphonic acid), 1-hydroxyethylidene-. Phosphonates such as 1,1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid) and salts thereof; and organic phosphoric acids such as phytic acid and salts thereof can be mentioned. The cation species of salts are not particularly limited, and examples thereof include Cu, Co, Fe, Mn, Sn, V, Mg, Ba, Al, Ca, Sr, Nb, Y, Ni, Zn and ammonium. It is preferably Al and ammonium. These phosphoric acid compounds may be used alone or in combination of two or more.
クロムを含有する処理剤は、例えば、水及び水分散性アクリル樹脂と、アミノ基を有するシランカップリング剤と、クロム酸アンモニウムや重クロム酸アンモニウム等のクロムイオンの供給源とを含有する。水分散性アクリル樹脂は、例えばアクリル酸などのカルボキシル基含有モノマーとアクリル酸グリシジルなどのグリシジル基含有モノマーとを共重合させることで得られる。この化成処理剤から形成される保護層は、耐水性、耐食性、及び耐アルカリ性が高い。また、この化成処理剤から形成される保護層は、被覆めっき鋼板１の白錆や黒錆発生を抑制することができ、被覆めっき鋼板の耐食性が向上しうる。 The chromium-containing treatment agent contains, for example, water and a water-dispersible acrylic resin, a silane coupling agent having an amino group, and a source of chromium ions such as ammonium chromate and ammonium dichromate. The water-dispersible acrylic resin can be obtained by copolymerizing, for example, a carboxyl group-containing monomer such as acrylic acid and a glycidyl group-containing monomer such as glycidyl acrylate. The protective layer formed from this chemical conversion treatment agent has high water resistance, corrosion resistance, and alkali resistance. Further, the protective layer formed from this chemical conversion treatment agent can suppress the generation of white rust and black rust of the coated plated steel sheet 1, and can improve the corrosion resistance of the coated plated steel sheet 1.
保護層は、濃色顔料を含有することが好ましい。すなわち、化成処理剤は、濃色顔料を含有することが好ましい。保護層が濃色顔料を含有することで、めっき層の表面に黒変が生じた場合であっても、保護層が濃色顔料によって着色されるため、保護層によってめっき層の黒変が隠蔽されやすくなる。このため、被覆めっき鋼板の表面外観の変化を目立ちにくくすることができる。濃色顔料の例は、カーボンブラック、鉄黒、酸化クロム、酸化鉄、及びアルミン酸クロムを含む。これらのうちの１種を単独で用いてもよく、２種以上を組み合わせて用いてもよい。 The protective layer preferably contains a dark pigment. That is, the chemical conversion treatment agent preferably contains a dark pigment. Since the protective layer contains a dark pigment, even if the surface of the plating layer is blackened, the protective layer is colored by the dark pigment, so that the protective layer hides the blackening of the plating layer. It becomes easy to be done. Therefore, the change in the surface appearance of the coated plated steel sheet can be made inconspicuous. Examples of dark pigments include carbon black, iron black, chromium oxide, iron oxide, and chromium aluminate. One of these may be used alone, or two or more thereof may be used in combination.
濃色顔料は、保護層に０．１質量％以上３．０質量％以下で含有されることが好ましい。濃色顔料が、保護層に０．１質量％以上含有されることで、めっき層に黒変が生じた場合でも、黒変が隠蔽されやすくなる。このため、被覆めっき鋼板の表面外観の変化を目立ちにくくすることができる。また、濃色顔料が、保護層に３．０質量％以下で含有されることで、被覆めっき鋼板の金属光沢が低下することを防ぐことができる。濃色顔料は、保護層に０．３質量％以上１．５質量％以下で含有されることがより好ましい。 The dark pigment is preferably contained in the protective layer in an amount of 0.1% by mass or more and 3.0% by mass or less. When the dark pigment is contained in the protective layer in an amount of 0.1% by mass or more, the blackening is easily concealed even when the plating layer is blackened. Therefore, the change in the surface appearance of the coated plated steel sheet can be made inconspicuous. Further, when the dark pigment is contained in the protective layer in an amount of 3.0% by mass or less, it is possible to prevent the metallic luster of the coated plated steel sheet from being lowered. It is more preferable that the dark pigment is contained in the protective layer in an amount of 0.3% by mass or more and 1.5% by mass or less.
保護層は、濃色顔料以外の添加剤をさらに含有してもよい。保護層は、例えば、濃色顔
料以外の顔料、無機粒子、有機粒子、架橋剤、密着性付与剤、及び防錆剤等を含有しうる。すなわち、化成処理剤は、濃色顔料以外の顔料、無機粒子、有機粒子、架橋剤、密着性付与剤、及び防錆剤等の添加剤を含有しうる。
The protective layer may further contain additives other than the dark pigment. The protective layer may contain, for example, pigments other than dark pigments, inorganic particles, organic particles, cross-linking agents, adhesion-imparting agents, rust preventives, and the like. That is, the chemical conversion treatment agent may contain pigments other than dark pigments, inorganic particles, organic particles, cross-linking agents, adhesion-imparting agents, and additives such as rust preventives.
保護層は、１．５以上の屈折率を有する無機粒子を含有することが好ましい。すなわち、化成処理剤は、１．５以上の屈折率を有する無機粒子を含有することが好ましい。保護層が、１．５以上の屈折率を有する無機粒子を含有することで、めっき層の表面に黒変が生じたとしても、光が保護層において拡散反射され、黒変が隠蔽されやすくなる。このため、被覆めっき鋼板の表面外観の変化を目立ちにくくすることができる。 The protective layer preferably contains inorganic particles having a refractive index of 1.5 or more. That is, the chemical conversion treatment agent preferably contains inorganic particles having a refractive index of 1.5 or more. When the protective layer contains inorganic particles having a refractive index of 1.5 or more, even if blackening occurs on the surface of the plating layer, light is diffusely reflected by the protective layer, and the blackening is easily concealed. .. Therefore, the change in the surface appearance of the coated plated steel sheet can be made inconspicuous.
１．５以上の屈折率を有する無機粒子の例は、酸化チタン、炭酸カルシウム、酸化亜鉛、鉄黒、硫酸バリウム、及びカーボンブラックを含む。これらのうちの１種を単独で用いてもよく、２種以上を組み合わせて用いてもよい。 Examples of inorganic particles having a refractive index of 1.5 or higher include titanium oxide, calcium carbonate, zinc oxide, iron black, barium sulfate, and carbon black. One of these may be used alone, or two or more thereof may be used in combination.
保護層は、２．０以上の屈折率を有する無機粒子を含有することがより好ましい。この場合、被覆めっき鋼板の表面外観の変化をより目立ちにくくすることができる。１．５以上の屈折率を有する無機粒子の屈折率の上限は特に限定されないが、例えば４．０以下である。 The protective layer more preferably contains inorganic particles having a refractive index of 2.0 or more. In this case, the change in the surface appearance of the coated plated steel sheet can be made less noticeable. The upper limit of the refractive index of the inorganic particles having a refractive index of 1.5 or more is not particularly limited, but is, for example, 4.0 or less.
保護層に含有される１．５以上の屈折率を有する無機粒子と、保護層に含有されるガラス転移温度が４０℃以上である樹脂との屈折率差は、絶対値で０．３以上であることが好ましい。この場合、保護層において光がより拡散反射されやすくなるため、めっき層の表面に黒変が生じたとしても、黒変がより目立ちにくくなる。保護層に含有される１．５以上の屈折率を有する無機粒子と、保護層に含有されるガラス転移温度が４０℃以上である樹脂との屈折率差は、絶対値で０．５以上であることがより好ましい。保護層に含有される１．５以上の屈折率を有する無機粒子と、保護層に含有されるガラス転移温度が４０℃以上である樹脂との屈折率差の上限は、特に限定されないが、例えば絶対値で３．０以下であってよい。 The difference in refractive index between the inorganic particles contained in the protective layer having a refractive index of 1.5 or more and the resin contained in the protective layer having a glass transition temperature of 40 ° C. or more is 0.3 or more in absolute value. It is preferable to have. In this case, since light is more easily diffusely reflected in the protective layer, even if blackening occurs on the surface of the plating layer, the blackening becomes less noticeable. The difference in refractive index between the inorganic particles contained in the protective layer having a refractive index of 1.5 or more and the resin contained in the protective layer having a glass transition temperature of 40 ° C. or more is 0.5 or more in absolute value. More preferably. The upper limit of the difference in refractive index between the inorganic particles having a refractive index of 1.5 or more contained in the protective layer and the resin contained in the protective layer having a glass transition temperature of 40 ° C. or more is not particularly limited, but for example. The absolute value may be 3.0 or less.
保護層に含有される１．５以上の屈折率を有する無機粒子の平均粒径は、０．１μｍ以上１．０μｍ以下であることが好ましい。この無機粒子の平均粒径が０．１μｍ以上であることで、保護層は、めっき層の表面の黒変をより目立たなくすることができる。また、この無機粒子の平均粒径が１．０μｍ以下であることで、無機粒子が保護層からはみ出て保護層の表面の平滑性が低下することを防げるため、保護層の耐食性が低下することを抑制できる。１．５以上の屈折率を有する無機粒子の平均粒径は、０．２μｍ以上０．５μｍ以下であることがより好ましい。この場合、保護層は、めっき層の表面の黒変を更に目立たなくすることができる。無機粒子の平均粒径は、レーザー回折・散乱法による粒度分布の測定値から算出される体積基準のメディアン径であり、市販のレーザー解析・散乱式粒度分布測定装置を用いて得られる。 The average particle size of the inorganic particles having a refractive index of 1.5 or more contained in the protective layer is preferably 0.1 μm or more and 1.0 μm or less. When the average particle size of the inorganic particles is 0.1 μm or more, the protective layer can make the blackening of the surface of the plating layer less noticeable. Further, when the average particle size of the inorganic particles is 1.0 μm or less, it is possible to prevent the inorganic particles from protruding from the protective layer and lowering the smoothness of the surface of the protective layer, so that the corrosion resistance of the protective layer is lowered. Can be suppressed. The average particle size of the inorganic particles having a refractive index of 1.5 or more is more preferably 0.2 μm or more and 0.5 μm or less. In this case, the protective layer can make the blackening of the surface of the plating layer less noticeable. The average particle size of the inorganic particles is a volume-based median diameter calculated from the measured value of the particle size distribution by the laser diffraction / scattering method, and can be obtained by using a commercially available laser analysis / scattering type particle size distribution measuring device.
保護層が１．５以上の屈折率を有する無機粒子を含有する場合、この無機粒子は、保護層に０．１質量％以上５．０質量％以下で含有されることが好ましい。１．５以上の屈折率を有する無機粒子が、保護層に０．１質量％以上含有されることで、光が保護層において十分に拡散反射され、めっき層の表面に黒変が生じても、表面外観の変化がより目立ちにくくなる。また、この無機粒子が、保護層に５．０質量％以下で含有されることで、被覆めっき鋼板の金属光沢が低下することを防ぐことができる。このため、被覆めっき鋼板は、無塗装の状態であっても、表面外観の変化が抑制され、また十分な金属光沢を有しうる。１．５以上の屈折率を有する無機粒子は、保護層に０．３質量％以上３．０質量％以下で含有されることがより好ましい。 When the protective layer contains inorganic particles having a refractive index of 1.5 or more, the inorganic particles are preferably contained in the protective layer in an amount of 0.1% by mass or more and 5.0% by mass or less. Even if the protective layer contains 0.1% by mass or more of inorganic particles having a refractive index of 1.5 or more, light is sufficiently diffusely reflected by the protective layer and the surface of the plating layer is blackened. , The change in surface appearance becomes less noticeable. Further, when the inorganic particles are contained in the protective layer in an amount of 5.0% by mass or less, it is possible to prevent the metallic luster of the coated plated steel sheet from being lowered. Therefore, the coated plated steel sheet can suppress the change in surface appearance and have a sufficient metallic luster even in the unpainted state. It is more preferable that the inorganic particles having a refractive index of 1.5 or more are contained in the protective layer in an amount of 0.3% by mass or more and 3.0% by mass or less.
保護層に含有される１．５以上の屈折率を有する無機粒子は、白色顔料を含むことが好ましい。すなわち、保護層は、白色顔料を含有することが好ましい。保護層が白色顔料を含有することで、保護層において光がより拡散反射されやすくなるため、めっき層の表面の黒変が更に目立ちにくくなる。白色顔料の例は、酸化チタン、酸化亜鉛、硫酸バリウム、酸化アルミニウム、酸化マグネシウム、及び炭酸カルシウムを含む。これらのうちの１種を単独で用いてもよく、２種以上を組み合わせて用いてもよい。 The inorganic particles having a refractive index of 1.5 or more contained in the protective layer preferably contain a white pigment. That is, the protective layer preferably contains a white pigment. When the protective layer contains a white pigment, light is more easily diffusely reflected in the protective layer, so that blackening of the surface of the plating layer becomes less noticeable. Examples of white pigments include titanium oxide, zinc oxide, barium sulphate, aluminum oxide, magnesium oxide, and calcium carbonate. One of these may be used alone, or two or more thereof may be used in combination.
保護層に含有される白色顔料は、酸化チタンを含むことが特に好ましい。すなわち、保護層は、酸化チタンを含有することが好ましい。保護層が酸化チタンを含有することで、保護層において光が特に拡散反射されやすくなるため、めっき層の表面の黒変が特に目立ちにくくなる。 The white pigment contained in the protective layer preferably contains titanium oxide. That is, the protective layer preferably contains titanium oxide. When the protective layer contains titanium oxide, light is particularly easily diffusely reflected in the protective layer, so that blackening of the surface of the plating layer becomes particularly inconspicuous.
保護層が白色顔料を含有する場合、白色顔料は、保護層に０．１質量％以上５．０質量％以下で含有されることが好ましい。白色顔料が、保護層に０．１質量％以上含有されることで、光が保護層において十分に拡散反射され、めっき層の表面の黒変がより目立ちにくくなる。また、白色顔料が、保護層に５．０質量％以下で含有されることで、被覆めっき鋼板の金属光沢が低下することを防ぐことができる。このため、被覆めっき鋼板は、無塗装の状態であっても、無塗装の状態であっても、表面外観の変化が抑制され、また十分な金属光沢を有しうる。白色顔料は、保護層に１．０質量％以上３．０質量％以下で含有されることがより好ましい。 When the protective layer contains a white pigment, the white pigment is preferably contained in the protective layer in an amount of 0.1% by mass or more and 5.0% by mass or less. When the white pigment is contained in the protective layer in an amount of 0.1% by mass or more, light is sufficiently diffusely reflected by the protective layer, and blackening on the surface of the plating layer becomes less noticeable. Further, when the white pigment is contained in the protective layer in an amount of 5.0% by mass or less, it is possible to prevent the metallic luster of the coated plated steel sheet from being lowered. Therefore, the coated plated steel sheet can have a sufficient metallic luster while suppressing a change in surface appearance regardless of whether it is in an unpainted state or an unpainted state. It is more preferable that the white pigment is contained in the protective layer in an amount of 1.0% by mass or more and 3.0% by mass or less.
保護層の付着量は、０．３ｇ／ｍ２以上５．０ｇ／ｍ２以下であることが好ましい。保護層の付着量がこの範囲内であることで、保護層が良好な耐食性を有する。保護層の付着量は、０．５ｇ／ｍ２以上３．０ｇ／ｍ２以下であることがより好ましい。 The amount of the protective layer adhered is preferably 0.3 g / m 2 or more and 5.0 g / m 2 or less. When the amount of adhesion of the protective layer is within this range, the protective layer has good corrosion resistance. The amount of the protective layer adhered is more preferably 0.5 g / m 2 or more and 3.0 g / m 2 or less.
めっき層と保護層との間には、保護層以外の化成処理層が形成されていてもよい。また、めっき層上にニッケルめっき処理、コバルトめっき処理といっためっき処理が施されていてもよい。 A chemical conversion treatment layer other than the protective layer may be formed between the plating layer and the protective layer. Further, the plating layer may be subjected to a plating treatment such as a nickel plating treatment or a cobalt plating treatment.
また保護層上に、塗料を塗布して塗膜が形成されてもよい。たとえば、樹脂及び顔料を含有する塗料を保護層上に塗布し、焼付を行うことで塗膜を形成することができる。また、保護層上にクリア塗料を塗布、成膜してクリア層を形成してもよい。ただし、本実施形態では、被覆めっき鋼板は、ガラス転移温度が４０℃以上である樹脂を含有する保護層を備えるため、めっき層の表面の黒変が生じにくく、無塗装であっても、表面外観の変化が抑制される。 Further, a coating film may be formed by applying a paint on the protective layer. For example, a coating film can be formed by applying a coating material containing a resin and a pigment on a protective layer and baking the coating film. Further, the clear paint may be applied on the protective layer and formed into a film to form the clear layer. However, in the present embodiment, since the coated plated steel sheet includes a protective layer containing a resin having a glass transition temperature of 40 ° C. or higher, blackening of the surface of the plated layer is unlikely to occur, and even if the surface is unpainted, the surface is not easily blackened. Changes in appearance are suppressed.
めっき層及び保護層は、鋼板の片面にのみ設けられていてもよく、鋼板の両面のそれぞれに設けられていてもよい。 The plating layer and the protective layer may be provided on only one side of the steel sheet, or may be provided on both sides of the steel sheet.
［被覆めっき鋼板の製造方法］
本実施形態に係る被覆めっき鋼板は、鋼板にめっき処理を施すことでめっき層を形成し、更にめっき層の上に保護層を形成することで製造される。
[Manufacturing method of coated galvanized steel sheet]
The coated plated steel sheet according to the present embodiment is manufactured by forming a plating layer by subjecting the steel sheet to a plating treatment and further forming a protective layer on the plating layer.
鋼板をめっき処理する方法としては、例えば鋼板を、無酸化炉内で予備加熱した後に還元炉内で還元焼鈍し、続いて溶融めっき浴に浸漬してから引き上げる方法が挙げられる。また、鋼板をめっきする別の方法としては、例えば全還元炉を用いる方法が挙げられる。いずれの方法においても、鋼板に溶融めっき金属を付着させてから、ガスワイピング方式で、溶融めっき金属の付着量を調整し、次いで冷却することで、鋼板にめっき層を形成することができる。これらの工程は連続的に行うことができる。 Examples of the method for plating a steel sheet include a method in which a steel sheet is preheated in a non-oxidizing furnace, then reduced and annealed in a reduction furnace, and then immersed in a hot-dip plating bath and then pulled up. Further, as another method for plating a steel sheet, for example, a method using a total reduction furnace can be mentioned. In either method, a plating layer can be formed on the steel sheet by adhering the hot-dip plated metal to the steel sheet, adjusting the amount of the hot-dip plated metal attached to the steel sheet by a gas wiping method, and then cooling the steel sheet. These steps can be performed continuously.
めっき層上に保護層を形成する前に、めっき層の表面に対する下地処理として、純水や各種有機溶剤液による洗浄や、酸、アルカリや各種エッチング剤を任意に含む水溶液や各種有機溶剤液による洗浄などが施されてもよい。このようにめっき層の表面が洗浄されると、めっき層の表層にＭｇ系酸化皮膜が少量存在したり、めっき層の表面に無機系及び有機系の汚れ等が付着していたりしても、これらのＭｇ系酸化皮膜や汚れ等がめっき層から除去され、これによりめっき層と保護層との密着性が改善され得る。 Before forming a protective layer on the plating layer, as a base treatment for the surface of the plating layer, cleaning with pure water or various organic solvent solutions, an aqueous solution containing an acid, alkali or various etching agents or various organic solvent solutions is used. It may be washed or the like. When the surface of the plating layer is cleaned in this way, even if a small amount of Mg-based oxide film is present on the surface layer of the plating layer or inorganic or organic stains are attached to the surface of the plating layer, These Mg-based oxide films, stains, and the like are removed from the plating layer, which can improve the adhesion between the plating layer and the protective layer.
保護層は、上述した化成処理剤を用いて形成される。まず、ロールコート法、スプレー法、浸漬法、電解処理法、エアーナイフ法など公知の方法で、化成処理剤をめっき層に塗布する。化成処理剤の塗布後、化成処理剤を硬化させることで保護層を形成する。化成処理剤の硬化方法は、例えば、常温放置や、熱風炉や電気炉、誘導加熱炉などの加熱装置による乾燥や焼付け、赤外線類、紫外線類や電子線類などエネルギー線を用いた方法が挙げられる。 The protective layer is formed by using the above-mentioned chemical conversion treatment agent. First, the chemical conversion treatment agent is applied to the plating layer by a known method such as a roll coating method, a spray method, a dipping method, an electrolytic treatment method, or an air knife method. After the chemical conversion treatment agent is applied, the protective layer is formed by curing the chemical conversion treatment agent. Examples of the curing method of the chemical conversion treatment agent include leaving at room temperature, drying and baking with a heating device such as a hot air furnace, an electric furnace, and an induction heating furnace, and a method using energy rays such as infrared rays, ultraviolet rays, and electron beams. Be done.
本実施形態では、めっき層上に塗布された化成処理剤を、７０℃以上１２０℃以下の温度で３秒以上１０秒以下加熱することで保護層を形成することが好ましい。この方法で形成された保護層は、腐食因子に対する優れた遮蔽性を有する。 In the present embodiment, it is preferable to form a protective layer by heating the chemical conversion treatment agent applied on the plating layer at a temperature of 70 ° C. or higher and 120 ° C. or lower for 3 seconds or longer and 10 seconds or shorter. The protective layer formed in this way has excellent shielding properties against corrosive factors.
このようにして形成される保護層は、めっき層上で、連続状若しくは非連続状の皮膜となる。保護層の厚みは、処理の種類、求められる性能などに応じて、適宜決定される。 The protective layer thus formed becomes a continuous or discontinuous film on the plating layer. The thickness of the protective layer is appropriately determined according to the type of treatment, the required performance, and the like.
以下、本発明を実施例によって具体的に説明する。しかし、本発明は以下の実施例に限定されるものではない。 Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the following examples.
（１）被覆めっき鋼板の作製
まず、鋼板上にめっき層（Ａｌ含有量５５質量％、Ｍｇ含有量２．０質量％、Ｚｎ含有量４１．４質量％、Ｓｉ含有量１．６質量％）を有する、厚み０．５ｍｍ、幅９００ｍｍの長尺のめっき鋼板（日鉄住金鋼板株式会社製のＳＧＬ鋼板）を用意した。
(1) Preparation of coated plated steel sheet First, a plating layer (Al content 55% by mass, Mg content 2.0% by mass, Zn content 41.4% by mass, Si content 1.6% by mass) is placed on the steel sheet. A long plated steel sheet (SGL steel sheet manufactured by Nittetsu Sumikin Steel Sheet Co., Ltd.) having a thickness of 0.5 mm and a width of 900 mm was prepared.
表１の「組成」の欄に示す組成を有する化成処理剤を、上記のめっき層の上にロールコーターにより塗布してから、最高到達温度が９０℃で５秒乾燥させることで、保護層を形成した。最高到達温度とは、乾燥時に到達する鋼板の最高温度を意味する。保護層の付着量は、表１の「付着量」の欄に示す通りである。 A chemical conversion treatment agent having the composition shown in the “Composition” column of Table 1 is applied onto the above-mentioned plating layer by a roll coater, and then dried at a maximum temperature of 90 ° C. for 5 seconds to form a protective layer. Formed. The maximum temperature reached means the maximum temperature of the steel sheet reached during drying. The amount of adhesion of the protective layer is as shown in the column of "amount of adhesion" in Table 1.
これにより、実施例１〜１０及び比較例１〜２の被覆めっき鋼板を得た。 As a result, coated plated steel sheets of Examples 1 to 10 and Comparative Examples 1 and 2 were obtained.
なお、表１の「組成」欄に記載の各成分の詳細は、以下の通りである。
・ウレタン樹脂Ａ：第一工業製薬株式会社製、品名スーパーフレックス１７０、ガラス転移温度７５℃、酸価２０ｍｇＫＯＨ／ｇ、最低造膜温度５℃、熱軟化温度１８８℃
・ウレタン樹脂Ｂ：第一工業製薬株式会社製、品名スーパーフレックス１５０、ガラス転移温度４０℃、酸価１５ｍｇＫＯＨ／ｇ、最低造膜温度５℃、熱軟化温度１９５℃
・ウレタン樹脂Ｃ：第一工業製薬株式会社製、品名スーパーフレックス２１０、ガラス転移温度４１℃、酸価４５ｍｇＫＯＨ／ｇ、最低造膜温度２３℃、熱軟化温度１２３℃
・ウレタン樹脂Ｄ：第一工業製薬株式会社製、品名スーパーフレックス１３０、ガラス転移温度１０１℃、酸価２０ｍｇＫＯＨ／ｇ、最低造膜温度５５℃、熱軟化温度１７４℃
・アクリル樹脂：ＤＩＣ株式会社製、品名ボンコートＥＭ−４０１、ガラス転移温度４５℃、酸価１０ｍｇＫＯＨ／ｇ、最低造膜温度４５℃
・ウレタン樹脂ａ：第一工業製薬株式会社製、品名スーパーフレックス８６０、ガラス転移温度３６℃、酸価１０ｍｇＫＯＨ／ｇ、最低造膜温度２８℃、熱軟化温度６０℃
・有機ケイ素化合物：信越化学工業株式会社製、品名ＯＦＳ−６０２０
・尿素／ホルムアルデヒド系架橋剤：ＤＩＣ株式会社製、品名ベッカミンＮ−８０
・Ｃｒ・Ｆｅ焼成顔料：東罐マテリアル・テクノロジー株式会社製、品名４２−７０７Ａ
・カーボンブラック：三菱ケミカル株式会社製、品名ＭＡ１００
・無機粒子：石原産業株式会社製、品名タイペークＣＲ−９０、屈折率２．７２、平均粒径０．２５μｍ
・界面活性剤：ビッグケミー・ジャパン株式会社製、品名ＢＹＫ−３４８
The details of each component described in the "Composition" column of Table 1 are as follows.
-Urethane resin A: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name Superflex 170, glass transition temperature 75 ° C, acid value 20 mgKOH / g, minimum film formation temperature 5 ° C, thermal softening temperature 188 ° C
-Urethane resin B: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name Superflex 150, glass transition temperature 40 ° C, acid value 15 mgKOH / g, minimum film formation temperature 5 ° C, thermal softening temperature 195 ° C.
-Urethane resin C: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name Superflex 210, glass transition temperature 41 ° C, acid value 45 mgKOH / g, minimum film formation temperature 23 ° C, thermal softening temperature 123 ° C.
-Urethane resin D: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name Superflex 130, glass transition temperature 101 ° C, acid value 20 mgKOH / g, minimum film formation temperature 55 ° C, thermal softening temperature 174 ° C.
-Acrylic resin: manufactured by DIC Corporation, product name Boncoat EM-401, glass transition temperature 45 ° C, acid value 10 mgKOH / g, minimum film formation temperature 45 ° C
-Urethane resin a: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name Superflex 860, glass transition temperature 36 ° C, acid value 10 mgKOH / g, minimum film formation temperature 28 ° C, thermal softening temperature 60 ° C.
-Organosilicon compound: manufactured by Shin-Etsu Chemical Co., Ltd., product name OFS-6020
-Urea / formaldehyde-based cross-linking agent: manufactured by DIC Corporation, product name Beccamin N-80
-Cr / Fe calcined pigment: manufactured by Tokan Material Technology Co., Ltd., product name 42-707A
-Carbon black: Made by Mitsubishi Chemical Corporation, product name MA100
-Inorganic particles: manufactured by Ishihara Sangyo Co., Ltd., product name Typake CR-90, refractive index 2.72, average particle size 0.25 μm
-Surfactant: Made by Big Chemie Japan Co., Ltd., Product name BYK-348
（２）被覆めっき鋼板の評価
（２−１）ΔＬ＊（初期）の測定
変角色差計（Ｘ−Ｒｉｔｅ株式会社製、品番ＭＡ−６８ＩＩ）を用いて、透かし角度を１１０°に設定し、作製直後の実施例１〜１０及び比較例１〜２の被覆めっき鋼板の保護層上のＬ＊値を、長さ方向に１００ｍｍ間隔で５箇所の位置で測定した。このＬ＊値の最大値と最小値の差を絶対値で「ΔＬ＊（初期）」欄に示す。
(2) Evaluation of coated galvanized steel sheet (2-1) Measurement of ΔL * (initial) Using a variable angle color difference meter (manufactured by X-Rite Co., Ltd., product number MA-68II), set the watermark angle to 110 ° and set the watermark angle to 110 °. Immediately after production, the L * values on the protective layer of the coated plated steel sheets of Examples 1 to 10 and Comparative Examples 1 and 2 were measured at five positions at 100 mm intervals in the length direction. The difference between the maximum value and the minimum value of this L * value is shown in the "ΔL * (initial)" column as an absolute value.
（２−２）ΔＬ＊（７日後）の測定
作製した実施例１〜１０及び比較例１〜２の被覆めっき鋼板を、屋外に７日間保管した。その後、ΔＬ＊（初期）の測定方法と同様の方法でＬ＊値を測定した。このＬ＊値の最大値と最小値の差を絶対値で「ΔＬ＊（７日後）」欄に示す。
(2-2) Measurement of ΔL * (7 days later) The prepared coated plated steel sheets of Examples 1 to 10 and Comparative Examples 1 and 2 were stored outdoors for 7 days. Then, the L * value was measured by the same method as the measurement method of ΔL * (initial). The difference between the maximum value and the minimum value of this L * value is shown in the "ΔL * (7 days later)" column as an absolute value.
（２−３）目視評価
実施例１〜１０及び比較例１〜２の被覆めっき鋼板を屋外に７日間保管した後の、作製直後からの表面外観の変化を、目視によって観察し、以下の基準で評価した。その結果を表１の「目視」欄に示す。
Ａ：黒変は観察されず、表面外観の変化は確認されない。
Ｂ：微小な黒変が観察されるが、表面外観の大きな変化は確認されない。
Ｃ：黒変が観察され、表面外観の変化が確認される。
(2-3) Visual Evaluation The changes in the surface appearance immediately after the production of the coated plated steel sheets of Examples 1 to 10 and Comparative Examples 1 and 2 after being stored outdoors for 7 days were visually observed, and the following criteria were used. Evaluated in. The results are shown in the "Visual" column of Table 1.
A: No blackening is observed, and no change in surface appearance is confirmed.
B: A slight blackening is observed, but a large change in the surface appearance is not confirmed.
C: Blackening is observed, and a change in surface appearance is confirmed.
（２−４）金属光沢
実施例１〜１０及び比較例１〜２の被覆めっき鋼板におけるめっき層の表面の金属光沢を、目視によって観察し、以下の基準で評価した。その結果を表１の「金属光沢」欄に示す。
Ａ：めっき層の表面の金属光沢は、良好であった。
Ｂ：めっき層の表面に金属光沢が良好ではない箇所がみられた。
(2-4) Metallic luster The metallic luster on the surface of the plated layer in the coated plated steel sheets of Examples 1 to 10 and Comparative Examples 1 and 2 was visually observed and evaluated according to the following criteria. The results are shown in the "Metallic luster" column of Table 1.
A: The metallic luster on the surface of the plating layer was good.
B: There were some spots on the surface of the plating layer where the metallic luster was not good.
（２−５）遮熱性
紫外可視近赤外分光光度計（島津製作所株式会社製、品番ＵＶ−３６００Ｐｌｕｓ）を用いて、実施例８及び９の被覆めっき鋼板のＪＩＳ Ｋ ５６０２で規定される７８０〜２５００ｎｍでの日射反射率を測定した。その結果を、以下の基準で評価し、表１の「遮熱性」欄に示す。
Ａ：被覆めっき鋼板の日射反射率が、６０％以上であった。
Ｂ：被覆めっき鋼板の日射反射率が、６０％未満であった。
(2-5) Heat Shielding Using an ultraviolet-visible near-infrared spectrophotometer (manufactured by Shimadzu Corporation, product number UV-3600Plus), the coated plated steel sheets of Examples 8 and 9 are 780 to specified in JIS K 5602. The solar reflectance at 2500 nm was measured. The results are evaluated according to the following criteria and are shown in the "heat shield" column of Table 1.
A: The solar reflectance of the coated plated steel sheet was 60% or more.
B: The solar reflectance of the coated plated steel sheet was less than 60%.
Claims (11)
前記めっき層は、Ａｌ、Ｚｎ、及びＭｇを含有し、
前記めっき層の、Ａｌ含有量は４５質量％以上６５質量％以下であり、Ｍｇ含有量は６．０質量％以下であり、
前記保護層は、ウレタン樹脂を含有する化成処理剤から形成され、
前記ウレタン樹脂のガラス転移温度は、４０℃以上であり、
前記保護層の付着量は、０．３ｇ／ｍ２以上５．０ｇ／ｍ２以下である、
被覆めっき鋼板。 A steel plate, a plating layer, and a protective layer are laminated in this order and provided.
The plating layer contains Al, Zn, and Mg and contains
The Al content of the plating layer is 45% by mass or more and 65% by mass or less, and the Mg content is 6.0% by mass or less.
The protective layer is formed of a chemical conversion treatment agent containing a urethane resin.
The glass transition temperature of the urethane resin is 40 ° C. or higher.
The amount of the protective layer adhered is 0.3 g / m 2 or more and 5.0 g / m 2 or less.
Coated galvanized steel sheet.
請求項１に記載の被覆めっき鋼板。 The acid value of the urethane resin is 15 mgKOH / g or more.
The coated plated steel sheet according to claim 1.
請求項１又は２に記載の被覆めっき鋼板。 The urethane resin has a minimum film forming temperature of 50 ° C. or lower and a thermal softening temperature of 200 ° C. or lower.
The coated plated steel sheet according to claim 1 or 2.
請求項１〜３のいずれか１項に記載の被覆めっき鋼板。 The chemical conversion treatment agent contains a cross-linking agent.
The coated plated steel sheet according to any one of claims 1 to 3.
請求項４に記載の被覆めっき鋼板。 The cross-linking agent contains at least one selected from the group consisting of an organosilicon compound having a cross-linking functional group, an epoxy-based cross-linking agent, an oxazoline-based cross-linking agent, a carbodiimide-based cross-linking agent, and a blocked isocyanate-based cross-linking agent.
The coated plated steel sheet according to claim 4.
請求項１〜５のいずれか１項に記載の被覆めっき鋼板。 The protective layer contains a dark pigment.
The coated plated steel sheet according to any one of claims 1 to 5.
請求項６に記載の被覆めっき鋼板。 The dark pigment is contained in the protective layer in an amount of 0.1% by mass or more and 3.0% by mass or less.
The coated plated steel sheet according to claim 6.
請求項６又は７に記載の被覆めっき鋼板。 The solar reflectance at 780 to 2500 nm defined by JIS K 5602 is 60% or more.
The coated plated steel sheet according to claim 6 or 7.
請求項１〜８いずれか１項に記載の被覆めっき鋼板。 The protective layer contains inorganic particles having a refractive index of 1.5 or more, and the inorganic particles contain a white pigment.
The coated plated steel sheet according to any one of claims 1 to 8.
請求項９に記載の被覆めっき鋼板。 The white pigment contains titanium oxide,
The coated plated steel sheet according to claim 9.
前記化成処理剤を前記めっき層に塗布し、７０℃以上１２０℃以下の温度で３秒以上１０秒以下加熱することで前記保護層を形成する工程を含む、
被覆めっき鋼板の製造方法。 The method for producing a coated plated steel sheet according to any one of claims 1 to 10.
The step of forming the protective layer by applying the chemical conversion treatment agent to the plating layer and heating at a temperature of 70 ° C. or higher and 120 ° C. or lower for 3 seconds or longer and 10 seconds or shorter is included.
Manufacturing method of coated plated steel sheet.
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