CA2515806A1 - Method of forming an electrocoating film, electrocoating film, and electrodeposited article - Google Patents
Method of forming an electrocoating film, electrocoating film, and electrodeposited article Download PDFInfo
- Publication number
- CA2515806A1 CA2515806A1 CA002515806A CA2515806A CA2515806A1 CA 2515806 A1 CA2515806 A1 CA 2515806A1 CA 002515806 A CA002515806 A CA 002515806A CA 2515806 A CA2515806 A CA 2515806A CA 2515806 A1 CA2515806 A1 CA 2515806A1
- Authority
- CA
- Canada
- Prior art keywords
- electrocoating
- forming
- film
- energy beam
- activation energy
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000004070 electrodeposition Methods 0.000 title claims abstract description 119
- 238000000034 method Methods 0.000 title claims abstract description 55
- 239000000203 mixture Substances 0.000 claims abstract description 44
- 230000004913 activation Effects 0.000 claims abstract description 41
- 238000010438 heat treatment Methods 0.000 claims abstract description 29
- 238000000576 coating method Methods 0.000 claims abstract description 16
- 239000011248 coating agent Substances 0.000 claims abstract description 15
- 238000004140 cleaning Methods 0.000 claims abstract description 9
- 125000002091 cationic group Chemical group 0.000 claims description 11
- 125000001494 2-propynyl group Chemical group [H]C#CC([H])([H])* 0.000 claims description 9
- RWSOTUBLDIXVET-UHFFFAOYSA-O sulfonium Chemical compound [SH3+] RWSOTUBLDIXVET-UHFFFAOYSA-O 0.000 claims description 7
- 238000001816 cooling Methods 0.000 claims description 3
- 239000011342 resin composition Substances 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 125000000524 functional group Chemical group 0.000 description 16
- 239000000758 substrate Substances 0.000 description 14
- 239000003999 initiator Substances 0.000 description 13
- 239000011230 binding agent Substances 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 9
- 229920005989 resin Polymers 0.000 description 8
- 239000011347 resin Substances 0.000 description 8
- 230000005855 radiation Effects 0.000 description 7
- 238000010894 electron beam technology Methods 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 5
- VVBLNCFGVYUYGU-UHFFFAOYSA-N 4,4'-Bis(dimethylamino)benzophenone Chemical compound C1=CC(N(C)C)=CC=C1C(=O)C1=CC=C(N(C)C)C=C1 VVBLNCFGVYUYGU-UHFFFAOYSA-N 0.000 description 4
- ISAOCJYIOMOJEB-UHFFFAOYSA-N benzoin Chemical class C=1C=CC=CC=1C(O)C(=O)C1=CC=CC=C1 ISAOCJYIOMOJEB-UHFFFAOYSA-N 0.000 description 4
- 239000008367 deionised water Substances 0.000 description 4
- 229910021641 deionized water Inorganic materials 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 238000009281 ultraviolet germicidal irradiation Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 3
- 239000003822 epoxy resin Substances 0.000 description 3
- 125000003010 ionic group Chemical group 0.000 description 3
- -1 ketone peroxide Chemical class 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 3
- 229920000647 polyepoxide Polymers 0.000 description 3
- 230000003746 surface roughness Effects 0.000 description 3
- KWVGIHKZDCUPEU-UHFFFAOYSA-N 2,2-dimethoxy-2-phenylacetophenone Chemical compound C=1C=CC=CC=1C(OC)(OC)C(=O)C1=CC=CC=C1 KWVGIHKZDCUPEU-UHFFFAOYSA-N 0.000 description 2
- XMLYCEVDHLAQEL-UHFFFAOYSA-N 2-hydroxy-2-methyl-1-phenylpropan-1-one Chemical compound CC(C)(O)C(=O)C1=CC=CC=C1 XMLYCEVDHLAQEL-UHFFFAOYSA-N 0.000 description 2
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 2
- 229910052794 bromium Inorganic materials 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000008199 coating composition Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical compound [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- 229920001228 polyisocyanate Polymers 0.000 description 2
- 239000005056 polyisocyanate Substances 0.000 description 2
- 239000004814 polyurethane Substances 0.000 description 2
- 229920002635 polyurethane Polymers 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 125000003396 thiol group Chemical group [H]S* 0.000 description 2
- JNELGWHKGNBSMD-UHFFFAOYSA-N xanthone Chemical compound C1=CC=C2C(=O)C3=CC=CC=C3OC2=C1 JNELGWHKGNBSMD-UHFFFAOYSA-N 0.000 description 2
- MFEWNFVBWPABCX-UHFFFAOYSA-N 1,1,2,2-tetraphenylethane-1,2-diol Chemical compound C=1C=CC=CC=1C(C(O)(C=1C=CC=CC=1)C=1C=CC=CC=1)(O)C1=CC=CC=C1 MFEWNFVBWPABCX-UHFFFAOYSA-N 0.000 description 1
- MSAHTMIQULFMRG-UHFFFAOYSA-N 1,2-diphenyl-2-propan-2-yloxyethanone Chemical compound C=1C=CC=CC=1C(OC(C)C)C(=O)C1=CC=CC=C1 MSAHTMIQULFMRG-UHFFFAOYSA-N 0.000 description 1
- DKEGCUDAFWNSSO-UHFFFAOYSA-N 1,8-dibromooctane Chemical compound BrCCCCCCCCBr DKEGCUDAFWNSSO-UHFFFAOYSA-N 0.000 description 1
- 239000012956 1-hydroxycyclohexylphenyl-ketone Substances 0.000 description 1
- PIZHFBODNLEQBL-UHFFFAOYSA-N 2,2-diethoxy-1-phenylethanone Chemical compound CCOC(OCC)C(=O)C1=CC=CC=C1 PIZHFBODNLEQBL-UHFFFAOYSA-N 0.000 description 1
- YLZOPXRUQYQQID-UHFFFAOYSA-N 3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-1-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]propan-1-one Chemical compound N1N=NC=2CN(CCC=21)CCC(=O)N1CCN(CC1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F YLZOPXRUQYQQID-UHFFFAOYSA-N 0.000 description 1
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 229910001335 Galvanized steel Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 1
- 229920000877 Melamine resin Polymers 0.000 description 1
- 239000004640 Melamine resin Substances 0.000 description 1
- 229920001730 Moisture cure polyurethane Polymers 0.000 description 1
- SCKXCAADGDQQCS-UHFFFAOYSA-N Performic acid Chemical compound OOC=O SCKXCAADGDQQCS-UHFFFAOYSA-N 0.000 description 1
- 244000028419 Styrax benzoin Species 0.000 description 1
- 235000000126 Styrax benzoin Nutrition 0.000 description 1
- 235000008411 Sumatra benzointree Nutrition 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- XHPWRTXYJFNZAW-UHFFFAOYSA-N [[4-[2-(4-diazonioimino-2-sulfocyclohexa-2,5-dien-1-ylidene)ethylidene]-3-sulfocyclohexa-2,5-dien-1-ylidene]hydrazinylidene]azanide Chemical compound OS(=O)(=O)C1=CC(N=[N+]=[N-])=CC=C1C=CC1=CC=C(N=[N+]=[N-])C=C1S(O)(=O)=O XHPWRTXYJFNZAW-UHFFFAOYSA-N 0.000 description 1
- 150000008062 acetophenones Chemical class 0.000 description 1
- 125000003647 acryloyl group Chemical group O=C([*])C([H])=C([H])[H] 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 125000005370 alkoxysilyl group Chemical group 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 150000001408 amides Chemical class 0.000 description 1
- 229920003180 amino resin Polymers 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 229960002130 benzoin Drugs 0.000 description 1
- RWCCWEUUXYIKHB-UHFFFAOYSA-N benzophenone Chemical compound C=1C=CC=CC=1C(=O)C1=CC=CC=C1 RWCCWEUUXYIKHB-UHFFFAOYSA-N 0.000 description 1
- 239000012965 benzophenone Substances 0.000 description 1
- 150000008366 benzophenones Chemical class 0.000 description 1
- MQDJYUACMFCOFT-UHFFFAOYSA-N bis[2-(1-hydroxycyclohexyl)phenyl]methanone Chemical compound C=1C=CC=C(C(=O)C=2C(=CC=CC=2)C2(O)CCCCC2)C=1C1(O)CCCCC1 MQDJYUACMFCOFT-UHFFFAOYSA-N 0.000 description 1
- KAKZBPTYRLMSJV-UHFFFAOYSA-N butadiene group Chemical group C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000007607 die coating method Methods 0.000 description 1
- 239000003085 diluting agent Substances 0.000 description 1
- 238000007772 electroless plating Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 125000003700 epoxy group Chemical group 0.000 description 1
- 125000004185 ester group Chemical group 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000008397 galvanized steel Substances 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 239000002241 glass-ceramic Substances 0.000 description 1
- 235000019382 gum benzoic Nutrition 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000004310 lactic acid Substances 0.000 description 1
- 235000014655 lactic acid Nutrition 0.000 description 1
- 125000005439 maleimidyl group Chemical group C1(C=CC(N1*)=O)=O 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 125000003566 oxetanyl group Chemical group 0.000 description 1
- MMCOUVMKNAHQOY-UHFFFAOYSA-L oxido carbonate Chemical compound [O-]OC([O-])=O MMCOUVMKNAHQOY-UHFFFAOYSA-L 0.000 description 1
- 150000002923 oximes Chemical class 0.000 description 1
- FZUGPQWGEGAKET-UHFFFAOYSA-N parbenate Chemical compound CCOC(=O)C1=CC=C(N(C)C)C=C1 FZUGPQWGEGAKET-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000000059 patterning Methods 0.000 description 1
- 150000002978 peroxides Chemical class 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000004528 spin coating Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 229920002803 thermoplastic polyurethane Polymers 0.000 description 1
- YRHRIQCWCFGUEQ-UHFFFAOYSA-N thioxanthen-9-one Chemical compound C1=CC=C2C(=O)C3=CC=CC=C3SC2=C1 YRHRIQCWCFGUEQ-UHFFFAOYSA-N 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 150000007964 xanthones Chemical class 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
- B05D3/0209—Multistage baking
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/36—Successively applying liquids or other fluent materials, e.g. without intermediate treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/28—Processes for applying liquids or other fluent materials performed by transfer from the surfaces of elements carrying the liquid or other fluent material, e.g. brushes, pads, rollers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
- C09D5/4488—Cathodic paints
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D13/00—Electrophoretic coating characterised by the process
- C25D13/04—Electrophoretic coating characterised by the process with organic material
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D13/00—Electrophoretic coating characterised by the process
- C25D13/22—Servicing or operating apparatus or multistep processes
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/03—Use of materials for the substrate
- H05K1/05—Insulated conductive substrates, e.g. insulated metal substrate
- H05K1/056—Insulated conductive substrates, e.g. insulated metal substrate the metal substrate being covered by an organic insulating layer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
- B05D3/0254—After-treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/06—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation
- B05D3/061—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation using U.V.
- B05D3/065—After-treatment
- B05D3/067—Curing or cross-linking the coating
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/13—Moulding and encapsulation; Deposition techniques; Protective layers
- H05K2203/1333—Deposition techniques, e.g. coating
- H05K2203/135—Electrophoretic deposition of insulating material
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Materials Engineering (AREA)
- Electrochemistry (AREA)
- Metallurgy (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Wood Science & Technology (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Health & Medical Sciences (AREA)
- Molecular Biology (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Paints Or Removers (AREA)
Abstract
The present invention has for its object to provide a method of forming an electrocoating film having an excellent smoothness and exceptionally high dielectric properties with a drastically reduced incidence of pinhole formation, such an electrocoating film, and such an electrodeposited article.
A method of forming an electrocoating film comprising coating a work with an electrocoating composition curable by heating and irradiation with an activation energy beam in which an electrodepositing step, an aqueous cleaning step, a pre-baking step, an activation energy beam irradiation step, and a post-baking step are serially carried out in the order mentioned.
A method of forming an electrocoating film comprising coating a work with an electrocoating composition curable by heating and irradiation with an activation energy beam in which an electrodepositing step, an aqueous cleaning step, a pre-baking step, an activation energy beam irradiation step, and a post-baking step are serially carried out in the order mentioned.
Description
DESCRIPTION
METHOD OF FORMING AN ELECTROCOATING FILM, ELECTROCOATING
FILM, AND ELECTRODEPOSITED ARTICLE
TECHNICAL FIELD
The present invention relates to a method of forming an electroCOating film, an electrocoating film, and an electrodeposited article.
BACKGROUND TECHNOLOGY
Recently attempts have been made to form an insulating coating film from a coating on a metallic surface.
Regarding the substrate of a mufti-layer printed wiring board, for instance, a metallic substrate formed with an epoxy resin insulating layer on which an electric circuit is formed by electroless plating for improved heat dissipation, called a metal core PWB, has so far been developed (e.g. Itoh, Kinji: Introduction to Manufacture of Printed Wiring Boards for Certification of Printed Wiring Board Engineers, 1st Edition, July 6, 2001, pp.67-69).
However, the recent trend toward higher-integration and higher-density substrate boards presents with the problem of leaks between the metal substrate and the circuit due to the minute pinkoles existing in the insulating layer and, therefore, this insulating layer is required to have high dielectric properties.
Electrocoating compositions have excellent throwing powers and yield comparatively even coats regardless of the shape of work as well as sufficient dielectric properties so that attempts have been made to form insulating layers using electrocoating compositions. Although such attempts are rewarded with several advantages of electrocoating, this electroCOating film is usually not so flat and smooth as desired and tends to develop pinkoles owing to evolution of hydrogen gas in the electodepositing process, thus making it difficult to implement a high-level dielectric property using an electroCOating Composition.
SUWAR'.L ~F THE PRESENT INVENTION
The present invention has for its object to provide a method of forming an electrocoating film having an excellent smoothness and exceptionally high dielectric properties with a drastically reduced incidence of pinhole 1~ formation, such. an electrocoating film, and such an electrodeposited article.
The present invention is first directed to a method of forming an electrocoating film comprising coating a work with an electrocoating composition curable by heating and irradiation with an activation energy beam in which an eleCtrodepositing step, an aqueous cleaning step, a pre-baking step, an activation energy beam irradiation step, and a post-baking step are serially carried out in the order mentioned.
2~ The activation energy beam irradiation step may be carried out directly following said pre-baking step without cooling the work.
The heating in the above post-baking step may be continuous from the pre-baking step.
Preferably, the electrocoating composition comprises a resin composition containing sulfonium and propargyl groups.
Preferably, the electrocoating composition is a cationic electrocoating composition.
The present invention is further directed to an electrocoating film which is formed by the above method of forming an electrocoating film.
In addition, the present invention is directed to an electrodeposited article having the electroCOating film.
METHOD OF FORMING AN ELECTROCOATING FILM, ELECTROCOATING
FILM, AND ELECTRODEPOSITED ARTICLE
TECHNICAL FIELD
The present invention relates to a method of forming an electroCOating film, an electrocoating film, and an electrodeposited article.
BACKGROUND TECHNOLOGY
Recently attempts have been made to form an insulating coating film from a coating on a metallic surface.
Regarding the substrate of a mufti-layer printed wiring board, for instance, a metallic substrate formed with an epoxy resin insulating layer on which an electric circuit is formed by electroless plating for improved heat dissipation, called a metal core PWB, has so far been developed (e.g. Itoh, Kinji: Introduction to Manufacture of Printed Wiring Boards for Certification of Printed Wiring Board Engineers, 1st Edition, July 6, 2001, pp.67-69).
However, the recent trend toward higher-integration and higher-density substrate boards presents with the problem of leaks between the metal substrate and the circuit due to the minute pinkoles existing in the insulating layer and, therefore, this insulating layer is required to have high dielectric properties.
Electrocoating compositions have excellent throwing powers and yield comparatively even coats regardless of the shape of work as well as sufficient dielectric properties so that attempts have been made to form insulating layers using electrocoating compositions. Although such attempts are rewarded with several advantages of electrocoating, this electroCOating film is usually not so flat and smooth as desired and tends to develop pinkoles owing to evolution of hydrogen gas in the electodepositing process, thus making it difficult to implement a high-level dielectric property using an electroCOating Composition.
SUWAR'.L ~F THE PRESENT INVENTION
The present invention has for its object to provide a method of forming an electrocoating film having an excellent smoothness and exceptionally high dielectric properties with a drastically reduced incidence of pinhole 1~ formation, such. an electrocoating film, and such an electrodeposited article.
The present invention is first directed to a method of forming an electrocoating film comprising coating a work with an electrocoating composition curable by heating and irradiation with an activation energy beam in which an eleCtrodepositing step, an aqueous cleaning step, a pre-baking step, an activation energy beam irradiation step, and a post-baking step are serially carried out in the order mentioned.
2~ The activation energy beam irradiation step may be carried out directly following said pre-baking step without cooling the work.
The heating in the above post-baking step may be continuous from the pre-baking step.
Preferably, the electrocoating composition comprises a resin composition containing sulfonium and propargyl groups.
Preferably, the electrocoating composition is a cationic electrocoating composition.
The present invention is further directed to an electrocoating film which is formed by the above method of forming an electrocoating film.
In addition, the present invention is directed to an electrodeposited article having the electroCOating film.
The present invention is further directed to a method of forming a multilayer film in which the above electroCOating film is further coated with an overcoat.
The present invention is further directed to a multilayer film which is formed by the method of forming a multilayer film.
Furthermore, the present invention is directed to an article having the multilayer film.
DISCLOSURE OF INVENTION
The method of forming an electroCOating film according to the present invention is a method of forming an electrocoating film which comprises coating a work with an electroCOating composition curable by heating and irradiation with an activation energy beam, and comprises an electrodepositing step, an aqueous cleaning step, a pre-baking step, an activation energy beam irradiation step, and a post-baking step.
The electrocoating composition mentioned above contains a binder component curable by heating and irradiation with an activation energy beam in addition to ,the ionic groups necessary for electrodeposition. The binder component may be a component having a functional group curable by heating and irradiation with an activation energy beam or one having both a heat-curable functional group and an activation energy beam-curable functional group, and whichever of these can be employed.
The Curability by irradiation with an activation energy beam, as referred to above, includes not only the mode in which a Curing reaction is directly caused by an activation energy beam itself but also the mode in which a curing reaction is caused by the active species generated by an activation energy beam. The activation energy beam-curable functional group may include an unsaturated bond, such as a double bond or a triple bond, a combination of the above unsaturated bond and a thiol group, an epoxy group, a maleimide group, an oxetane group, an alkoxysilyl group and so on, but in consideration of the stability of coexistence with other functional groups, either an unsaturated bond or a combination of the above unsaturated bond and a thiol group is preferred. Moreover, said unsaturated bond is not only curable by irradiation with an activation energy beam but may be converted to a heat-curable functional group by formulating a heat-sensitive radical initiator, such as an dialkyl peroxide, peroxycarboxylic acid, peroxycarbonate, peroxy-ester, hydroperoxide, ketone peroxide, azodinitrile or benzopinacol silyl ether, in the coating.
Further, as the heat-curable functional group, those functional groups which are well known in the coating art can be utilized. The functional group mentioned above is not particularly restricted unless it directly reacts with said ionic group necessary for electrodeposition or said activation energy beam-curable functional group or interferes with the electodepositing process or the curing by an activation energy beam. Specifically, the preferred one is hydroxyl group. As regards this functional group capable of curing on exposure to heat, a curing agent serving as a partner in the curing reaction is usually incorporated in the coating composition. In the case where the functional group capable of curing on exposure to heat is hydroxyl, the curing agent which can be used may be any of those well known in the art, such as an optionally blocked polyisocyanate or melamine resin, for instance.
For example, Japanese Kokai Publication Hei-05-263026 discloses a UV-curable cationic elecrocoating composition comprising 10 to 70 parts lay weight of a polyfunctional acrylate having three or more acryloyl groups within the molecule and 30 to 90 parts by weight of a resin suitable for cationic electrodeposition and having an average molecular weight of 2000 to 30000 as active components.
Such electrocoating compositions containing a binder 5 component having an unsaturated bond as an activation energy beam-curable functional group are known and, therefore, by incorporating a heat-sensitive radical initiator in such. a known coating, there can be provided an electrocoating composition for use in the method of forming an electrocoating film according to the present invention.
Furthermore, it is not difficult for those skilled in the art to provide an electrocoating composition for use in the method of forming an electrocoating film by introducing a heat-curable functional group into a binder component having said unsaturated bond as an activation energy beam-curable functional group and selecting a curing agent compatible therewith.
Furthermore, an aqueous dispersion comprising a cathionic group-containing polyurethane (meth)acrylate having an ethylenically unsaturated terminal (meth)acryloyl double bond and a reactive diluent having at least two ethylenically unsaturated (meth)acryloyl double bonds as a binder component and a light-sensitive radical initiator and/or a heat-sensitive radical initiator, which is disclosed in Japanese Kohyo-Publication 2002-531676, can be used as the electrocoating composition for use in the method of forming an electrocoating film according to the present invention. Here, the (meth)acryloyl double bond in said aqueous dispersion has a bromine value equal to 20 to 150 g bromine/100 g solids and the terminal (meth)acryloyl double bond of ethylenic unsaturation from said polyurethane (meth)acrylate is bound to a cationic group-containing polyurethane prepolymer through a urethane, urea, amide or ester group.
Furthermore, a cationic electrocoating composition containing sulfonium and propargyl groups is disclosed in WO 98/03595. This electrocoating composition, too, can be used in the method of forming an electrocoating film according to the present invention. The sulfonium group content of this electrocoating composition per 100 g of resin solids is 5 to 400 millimoles and the propargyl group content on the same basis is 10 to 495 millimoles, the total content of sulfonium and propargyl groups being not greater than 500 millimoles. Furthermore, a Component containing a double bond as unsaturation in addition to propargyl group may also be used in combination.
Incidentally, it is known that said cationic electrocoating composition containing sulfonium and propargyl groups undergoes curing when heated even in the absence of the heat-sensitive radical initiator. Moreover, because it contains the propargyl group being an unsaturated bond, the coating can be cured by irradiation with an activation energy beam.
The electrocoating composition for use in the method of forming an electrocoating film according to the present invention may be whichever of an anionic electrocoating composition and a cationic electrocoating composition but is preferably a cationic electrocoating composition in view of the release of ions from the work.
From the standpoint of dielectric property of the formed electrocoating film, the electrocoating composition for use in the method of forming an electrocoating film according to the present invention is preferably said cationic electrocoating composition containing sulfonium and propargyl groups. As such cationic electroCOating composition, there can be mentioned Insuleed Series (electrolytically active electrocoatings, manufactured by Nippon Paint Co.) Where necessary, the electroCOating composition for use in the method of forming an electroCOating film according to the present invention may contain a light-sensitive radical initiator. As the light-sensitive radical initiator which can be comprised in said electrocoating composition, various compounds which are well known to those skilled in the art can be employed.
Among such substances are benzoin compounds such as benzoin, benzoin isopropyl ether, benzoin isobutyl ether, and so ona benzophenone compounds such as benzophenone, 4,4'-bis(dimethylamino)benzophenone (Michler's ketone), and so on~ xanthone compounds such as xanthone, thioxanthone, and so on; acetophenone compounds such as 2-phenyl-2-hydroxyacetophenone, a,cx-dichloro-4-phenoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,2-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-hydroxy-2-methylpropiophenone, 2,2-dimethoxy-2-phenylacetophenone (benzyl dimethyl ketal), and so on; ethyl 4-dimethylaminobenzoate, 4,4'-diazidostilbene-2,2'-disulfonic acid, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, and so forth. These light-sensitive radical initiators are usually formulated in a proportion of 0.1 to 10 o by weight based on the resin solids of the coating composition.
The electrocoating composition for use in the method of forming an electrocoating film according to the present invention may contain those pigments and additives which are conventionally formulated in electrocoating compositions.
The work for use in the method of forming an electrocoating film according to the present invention is not particularly restricted provided that the area to be coated is electrically conductive. There is no restriction on the shape of the work.
The electrodepositing step in the method of forming an electrocoating film according t~ the present invention comprises electrodepositing an electrically conductive work with the above-described electrocoating composition to give an uncured electrodeposited coat. The relevant electrodepositing conditions such as electrodepositing bath temperature, electrodepositing voltage and current time are established according to the particular electrocoating composition to be used but are preferably so set as to yield a dry film thickness of 5 to 30 um.
The aqueous cleaning step in the method of forming an electrocoating film according to the present invention, which is carried out on completion of said electrodepositing step, comprises washing off the superfluous electrocoating composition remaining on the work and electrodeposited coat. The solvent for use in this aqueous cleaning step is preferably deionized water from the standpoint of dielectric property of the resulting electrocoating film but there may optionally be used a two-stage method which comprises prewashing with a mixture solvent of deionized water and a water-soluble carboxylic acid compound, such as acetic acid, lactic acid or the like, and postwashing with deionized water. The residual electrocoating composition can be thereby removed more effectively.
The mode of the above aqueous cleaning is not particularly restricted but any of those techniques which are well known in the art, such as dipping and spraying, can be employed. The cleaning time is not particularly restricted but may, for example, be 30 seconds to 2 minutes.
The pre-baking step which is carried out on completion of said aqueous cleaning step in the method of forming an electrocoating film according to the present invention is not intended to cure the whole of said electrodeposited coat but intended to melt and let flow the uncured electrodeposited coat once formed to thereby eliminate film defects such as pinholes for improved evenness and surface smoothness of the coat. Therefore, even in the case where the heating is further continued, this step is regarded as having been completed at the time-point where the electrodeposited coat has been molten and let flow. The melting and letting-flow of the uncured electrodeposited coat in the above manner is advantageous in that an improvement in the smoothness of the coat as well as elimination of pinholes in the coat can be accomplished to insure a high degree of dielectric property.
Furthermore, improving the smoothness of the coat in this way enables the use of the obtained film in an electric circuit utilizing high-frequency signal. This is because a reduced coarseness of the coat leads to a reduction in the disturbance of the magnetic field by a current so that the product can be made adaptable to high-frequency current applications which are apt to be influenced by a magnetic field. Moreover, the improved surface smoothness can reduces the risk for disconnection of a conductor locating on an electrodeposited article and enables fine-lined conversion of the electrodeposited article on its patterning as well.
The heating temperature for use in the above pre-baking step should, of necessity, be not lower than the temperature causing the electrodeposited coat to melt and it can be judiciously selected according to the kind of electrocoating composition used but is generally within the range of 60 to 130°C. If it is below 60°C, the flow of the uncured electrodeposited coat on melting tends to be insufficient so that pinholes may remain after this step and the evenness or the surface smoothness of the coat may be insufficient. On the other hand, if the temperature exceeds 130°C, the uncured electrodeposited coat may begin to cure before the coat has flown sufficiently, with the consequence that, after this step, pinholes may remain, the evenness of the coat be inadequate, or the surface smoothness of the coat be insufficient. The preferred range is 70 to 110°C. The heating time in said pre-baking step is not particularly restricted but from coat meltability and industrial points of view, it may for example be 2 to 30 minutes.
The activation energy beam irradiation step in the 5 method of forming an electrocoating film according to the present invention, which precedes the post-baking step, is intended to fix the coat surface which has been improved in evenness and smoothness by said pre-baking step. By carrying out this step, the reflow of the electrodeposited 10 coat is inhibited so that even when the electrodeposited coat is further heated and caused to cure thoroughly, the ultimate electrocoating film can be obtained with the high surface smoothness achieved in this step being successfully retained.
The activation energy beam which can be used includes ultraviolet light, X-rays, an electron beam, near-infrared light and visible light. The activation energy beam in the context of the present invention does not include heat-generating energy beams such as infrared light, high-frequency waves and microwaves. However, although near-infrared light is a heat-generating energy beam, it is included in said activation energy beam because there exist light-sensitive radical initiators showing initiating functions in this wavelength region.
For irradiation with ultraviolet light, there can be used a variety of light sources, such as a mercury arc lamp, a xenon arc lamp, a fluorescent lamp, a carbon arc lamp, a tungsten-halogen copier lamp, and so forth. On the other hand, as emission sources of an electron beam, there can be used electron beam generators such as Cockcroft type, Cockcroft-Walton type, van de Graaff type, resonance transformer type, transformer type, insulating core transformer type, Dynamitron type, linear filament type, high-frequency type, and other devices. It should be understood that when an electron beam is used, it is not always necessary to use a light-sensitive radical initiator.
The conditions of said irradiation with an activation energy beam in this step vary with the amount of unsaturation in the resin and the molecular weight of the resin in the electroCOating composition used but taking ultraviolet light as an example of said activation energy beam, its wavelength range may be 200 to 500 nm and the integrating radiation dosage may for example be 100 to 10000 mJ/Cm2 when the coating used contains a light-sensitive radical initiator or 1000 to 20000 mJ/Cm2 when the coating does not contain a light-sensitive radical initiator. When the integrating radiation dosage is insufficient, fixing of the electrodeposited coat surface is inadequate so that the ultimate electrocoating film tends to be deficient in smoothness. An excessive integrating radiation dosage would not cause any serious trouble but lead to a waste of energy. On the other hand, when an electron beam is used, it is advantageous to carry out the irradiation using an electron beam generator with an output energy of 50 to 500 ke~T for a predetermined time.
It is also recommendable to adjust the distance between the electrodeposited coat and the light source according to the shape of the work so as to provide for a uniform irradiation with the activation energy beam and bring said integrating radiation dosage and energy into a predetermined range.
The above activation energy beam irradiation step may be carried out directly following said pre-baking step without cooling the work between the steps.
The post-baking step in the method of forming an electroCOating film according to the present invention is intended to thermally cure the electrodeposited coat having a fixed surface following the activation energy beam irradiation step. By carrying out this step, the entirety of the electrodeposited Coat inclusive of its interior Can be caused to cure thoroughly. Although the electrodeposited coat undergoes remelting to flow in this step, the coat surface which has been hardened in the preceding step does not melt so that all ultimately cured electrocoating film can be produced with the high surface smoothness obtained in the preceding step being fully retained.
The heating conditions for use in this post-baking step are not particularly restricted provided that the electrocoating film having a fixed surface obtained after said pre-baking step and subsequent activation energy beam irradiation step can be thoroughly cured down to its interior. The above heating conditions can be appropriately established according to the kind of electrocoating composition used and, for example, the heating temperature may be 130 to X60°C. The heating time in this post-baking step is not particularly restricted, either, and may for example be 10 to 30 minutes.
The heating in this post-baking step may be a continuation of the heating in said pre-baking step.
The method of forming an electrocoating film according to the present invention is applicable to electrically conductive substrates and can be used to form electrocoating films on various metallic materials such as copper, iron, galvanized steel sheet, aluminum and so forth.
The electrocoating film of the present invention is formed by the above-described method of forming an electrocoating film, and having such. a film, the electrodeposited article of the present invention features very satisfactory dielectric properties and surface smoothness.
The method of forming a multilayer film according to the present invention may comprise applying an overcoat in superimposition on the cured electrocoating film described above. The overcoat is intended to protect and impart an attractive appearance to said electrocoating film or adding new functions to the multilayer film. The overcoat mentioned just above is not particularly restricted but includes, for example, those materials which can be caused to undergo a curing reaction by heating and/or irradiation with an activation energy beam. Among specific examples are those binders, among the binder components mentioned in the foregoing description of the electrocoating composition of the present invention, which can be cured by heating 1~ and/or irradiation with an activation energy beam. In the case of a non-aqueous one, the binder need not have an ionic group. As the skeleton of the binder component, there can be used an acrylic resin, polyester resin, epoxy resin, urethane resin, or the like and where flexibility is further required, these resins may have been modified by introducing a butadiene skeleton, siloxane skeleton or long-chain aliphatic skeleton.
In the case where the overcoat is heat-curable but cannot be cured in the presence of said binder component alone, a curing agent suited to the kind of said reactive functional group can be used as an auxiliary binder component. The curing agent mentioned just above includes amino resins and optionally blocked polyisocyanates.
In addition to said binder component or components, the above overcoat may contain a pigment, a resin particle, and various additives. For imparting electrical conductivity as a new function to the multilayer film, the above overcoat may be supplemented with a metal particle, carbon, metal oxide, and/or the like. For imparting high 3~ dielectric properties, glass fiber, ceramics, and so on may be formulated.
The coating method is not particularly restricted but includes the techniques well known to those skilled in the art, such as bar coating, die coating, spray coating, rotary atomizer coating, spin coating, and so forth. By curing the resulting film by heating and/or irradiation with an activation energy beam, an overcoat can be constructed. The heating conditions and the conditions of activation energy beam irradiation can be judiciously established according to the kind of overcoat used. The cured thickness of the above overcoat is not particularly restricted but may, for example, be 10 to 100 lam.
The application of the overcoat may be carried out in a few divided cycles.
The multilayer film of the present invention is the film obtained by the above-described method of forming a multilayer film, and the article according to this invention has said multilayer film and, therefore, features a high degree of smoothness.
BEST MODE FOR CARRYING OUT THE PRESENT INVENTION
The following examples are intended to illustrate the present invention in further detail without defining the scope of the present invention. In the examples, "part(s)"
means "part(s) by weight" unless otherwise specified.
Example 1 Using Insuleed 1004 (product of Nippon Paint Co., an electrolytically active electrocoating, melting temperature 90°C, curing temperature 180°C), a copper substrate (10 cm x 10 cm x 700 um thick) was electrodeposited at an electrodepositing voltage of 200 V for 1 minute in a dry film thickness of 20 um to give an uncured electrodeposited coat. The temperature of the electrodepositing bath was 30°C. After electrodepositing, the substrate was cleaned by dipping it in deionized water for 1 minute to remove the superfluous electrocoating composition on the substrate and electrodeposited coat.
Then, the substrate carrying this uncured electrodeposited coat was pre-baked in a heating oven at a set temperature of 90°C for 10 minutes. After completion of this pre-baking, the substrate was taken out from the oven and the electrodeposited coat on the substrate surface was visually examined. It was found that the coat had flown sufficiently to become smooth.
5 Then, using a high-pressure mercury-vapor lamp (peak wavelength 365 nm, irradiation intensity 50 mJ/(cm2~s)), the substrate was irradiated with ultraviolet light at an integrating radiation dosage of 10000 mJ/cm'.
Thereafter, the substrate was post-baked in a heating 10 oven at a set temperature of 180°C for 20 minutes to give an electrocoating film.
Example 2 A substrate having an uncured electrodeposited coat 15 as obtained in the same manner as in Example 1 was used as the work. Meanwhile, a device capable of effecting both heating and UV irradiation was set to a heating temperature of 90°C and, for UV irradiation, to a peak wavelength of 365 nm, an irradiation intensity of 50 mJ/(cm~~s) and an integrating radiation dosage of 10000 mJ/cm2. Using the above device, heating alone was carried out for 9 minutes.
Then, with the heating being further continued under the same conditions as above for 1 minute, the work was irradiated with UV light for 1 minute.
Thereafter, the work was caused to cure by the post-baking in a heating oven set to 180°C for 20 minutes to give an electrocoating film.
Example 3 Using CCR-232GF (product of Asahi Chemical Research Co., an epoxy resin overcoat), the electrocoating film obtained in Example 2 was spray-coated in a cured thickness of 25 um. Then the work was cured by heating at 150°C for 60 minutes to give a multilayer film.
The present invention is further directed to a multilayer film which is formed by the method of forming a multilayer film.
Furthermore, the present invention is directed to an article having the multilayer film.
DISCLOSURE OF INVENTION
The method of forming an electroCOating film according to the present invention is a method of forming an electrocoating film which comprises coating a work with an electroCOating composition curable by heating and irradiation with an activation energy beam, and comprises an electrodepositing step, an aqueous cleaning step, a pre-baking step, an activation energy beam irradiation step, and a post-baking step.
The electrocoating composition mentioned above contains a binder component curable by heating and irradiation with an activation energy beam in addition to ,the ionic groups necessary for electrodeposition. The binder component may be a component having a functional group curable by heating and irradiation with an activation energy beam or one having both a heat-curable functional group and an activation energy beam-curable functional group, and whichever of these can be employed.
The Curability by irradiation with an activation energy beam, as referred to above, includes not only the mode in which a Curing reaction is directly caused by an activation energy beam itself but also the mode in which a curing reaction is caused by the active species generated by an activation energy beam. The activation energy beam-curable functional group may include an unsaturated bond, such as a double bond or a triple bond, a combination of the above unsaturated bond and a thiol group, an epoxy group, a maleimide group, an oxetane group, an alkoxysilyl group and so on, but in consideration of the stability of coexistence with other functional groups, either an unsaturated bond or a combination of the above unsaturated bond and a thiol group is preferred. Moreover, said unsaturated bond is not only curable by irradiation with an activation energy beam but may be converted to a heat-curable functional group by formulating a heat-sensitive radical initiator, such as an dialkyl peroxide, peroxycarboxylic acid, peroxycarbonate, peroxy-ester, hydroperoxide, ketone peroxide, azodinitrile or benzopinacol silyl ether, in the coating.
Further, as the heat-curable functional group, those functional groups which are well known in the coating art can be utilized. The functional group mentioned above is not particularly restricted unless it directly reacts with said ionic group necessary for electrodeposition or said activation energy beam-curable functional group or interferes with the electodepositing process or the curing by an activation energy beam. Specifically, the preferred one is hydroxyl group. As regards this functional group capable of curing on exposure to heat, a curing agent serving as a partner in the curing reaction is usually incorporated in the coating composition. In the case where the functional group capable of curing on exposure to heat is hydroxyl, the curing agent which can be used may be any of those well known in the art, such as an optionally blocked polyisocyanate or melamine resin, for instance.
For example, Japanese Kokai Publication Hei-05-263026 discloses a UV-curable cationic elecrocoating composition comprising 10 to 70 parts lay weight of a polyfunctional acrylate having three or more acryloyl groups within the molecule and 30 to 90 parts by weight of a resin suitable for cationic electrodeposition and having an average molecular weight of 2000 to 30000 as active components.
Such electrocoating compositions containing a binder 5 component having an unsaturated bond as an activation energy beam-curable functional group are known and, therefore, by incorporating a heat-sensitive radical initiator in such. a known coating, there can be provided an electrocoating composition for use in the method of forming an electrocoating film according to the present invention.
Furthermore, it is not difficult for those skilled in the art to provide an electrocoating composition for use in the method of forming an electrocoating film by introducing a heat-curable functional group into a binder component having said unsaturated bond as an activation energy beam-curable functional group and selecting a curing agent compatible therewith.
Furthermore, an aqueous dispersion comprising a cathionic group-containing polyurethane (meth)acrylate having an ethylenically unsaturated terminal (meth)acryloyl double bond and a reactive diluent having at least two ethylenically unsaturated (meth)acryloyl double bonds as a binder component and a light-sensitive radical initiator and/or a heat-sensitive radical initiator, which is disclosed in Japanese Kohyo-Publication 2002-531676, can be used as the electrocoating composition for use in the method of forming an electrocoating film according to the present invention. Here, the (meth)acryloyl double bond in said aqueous dispersion has a bromine value equal to 20 to 150 g bromine/100 g solids and the terminal (meth)acryloyl double bond of ethylenic unsaturation from said polyurethane (meth)acrylate is bound to a cationic group-containing polyurethane prepolymer through a urethane, urea, amide or ester group.
Furthermore, a cationic electrocoating composition containing sulfonium and propargyl groups is disclosed in WO 98/03595. This electrocoating composition, too, can be used in the method of forming an electrocoating film according to the present invention. The sulfonium group content of this electrocoating composition per 100 g of resin solids is 5 to 400 millimoles and the propargyl group content on the same basis is 10 to 495 millimoles, the total content of sulfonium and propargyl groups being not greater than 500 millimoles. Furthermore, a Component containing a double bond as unsaturation in addition to propargyl group may also be used in combination.
Incidentally, it is known that said cationic electrocoating composition containing sulfonium and propargyl groups undergoes curing when heated even in the absence of the heat-sensitive radical initiator. Moreover, because it contains the propargyl group being an unsaturated bond, the coating can be cured by irradiation with an activation energy beam.
The electrocoating composition for use in the method of forming an electrocoating film according to the present invention may be whichever of an anionic electrocoating composition and a cationic electrocoating composition but is preferably a cationic electrocoating composition in view of the release of ions from the work.
From the standpoint of dielectric property of the formed electrocoating film, the electrocoating composition for use in the method of forming an electrocoating film according to the present invention is preferably said cationic electrocoating composition containing sulfonium and propargyl groups. As such cationic electroCOating composition, there can be mentioned Insuleed Series (electrolytically active electrocoatings, manufactured by Nippon Paint Co.) Where necessary, the electroCOating composition for use in the method of forming an electroCOating film according to the present invention may contain a light-sensitive radical initiator. As the light-sensitive radical initiator which can be comprised in said electrocoating composition, various compounds which are well known to those skilled in the art can be employed.
Among such substances are benzoin compounds such as benzoin, benzoin isopropyl ether, benzoin isobutyl ether, and so ona benzophenone compounds such as benzophenone, 4,4'-bis(dimethylamino)benzophenone (Michler's ketone), and so on~ xanthone compounds such as xanthone, thioxanthone, and so on; acetophenone compounds such as 2-phenyl-2-hydroxyacetophenone, a,cx-dichloro-4-phenoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,2-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-hydroxy-2-methylpropiophenone, 2,2-dimethoxy-2-phenylacetophenone (benzyl dimethyl ketal), and so on; ethyl 4-dimethylaminobenzoate, 4,4'-diazidostilbene-2,2'-disulfonic acid, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, and so forth. These light-sensitive radical initiators are usually formulated in a proportion of 0.1 to 10 o by weight based on the resin solids of the coating composition.
The electrocoating composition for use in the method of forming an electrocoating film according to the present invention may contain those pigments and additives which are conventionally formulated in electrocoating compositions.
The work for use in the method of forming an electrocoating film according to the present invention is not particularly restricted provided that the area to be coated is electrically conductive. There is no restriction on the shape of the work.
The electrodepositing step in the method of forming an electrocoating film according t~ the present invention comprises electrodepositing an electrically conductive work with the above-described electrocoating composition to give an uncured electrodeposited coat. The relevant electrodepositing conditions such as electrodepositing bath temperature, electrodepositing voltage and current time are established according to the particular electrocoating composition to be used but are preferably so set as to yield a dry film thickness of 5 to 30 um.
The aqueous cleaning step in the method of forming an electrocoating film according to the present invention, which is carried out on completion of said electrodepositing step, comprises washing off the superfluous electrocoating composition remaining on the work and electrodeposited coat. The solvent for use in this aqueous cleaning step is preferably deionized water from the standpoint of dielectric property of the resulting electrocoating film but there may optionally be used a two-stage method which comprises prewashing with a mixture solvent of deionized water and a water-soluble carboxylic acid compound, such as acetic acid, lactic acid or the like, and postwashing with deionized water. The residual electrocoating composition can be thereby removed more effectively.
The mode of the above aqueous cleaning is not particularly restricted but any of those techniques which are well known in the art, such as dipping and spraying, can be employed. The cleaning time is not particularly restricted but may, for example, be 30 seconds to 2 minutes.
The pre-baking step which is carried out on completion of said aqueous cleaning step in the method of forming an electrocoating film according to the present invention is not intended to cure the whole of said electrodeposited coat but intended to melt and let flow the uncured electrodeposited coat once formed to thereby eliminate film defects such as pinholes for improved evenness and surface smoothness of the coat. Therefore, even in the case where the heating is further continued, this step is regarded as having been completed at the time-point where the electrodeposited coat has been molten and let flow. The melting and letting-flow of the uncured electrodeposited coat in the above manner is advantageous in that an improvement in the smoothness of the coat as well as elimination of pinholes in the coat can be accomplished to insure a high degree of dielectric property.
Furthermore, improving the smoothness of the coat in this way enables the use of the obtained film in an electric circuit utilizing high-frequency signal. This is because a reduced coarseness of the coat leads to a reduction in the disturbance of the magnetic field by a current so that the product can be made adaptable to high-frequency current applications which are apt to be influenced by a magnetic field. Moreover, the improved surface smoothness can reduces the risk for disconnection of a conductor locating on an electrodeposited article and enables fine-lined conversion of the electrodeposited article on its patterning as well.
The heating temperature for use in the above pre-baking step should, of necessity, be not lower than the temperature causing the electrodeposited coat to melt and it can be judiciously selected according to the kind of electrocoating composition used but is generally within the range of 60 to 130°C. If it is below 60°C, the flow of the uncured electrodeposited coat on melting tends to be insufficient so that pinholes may remain after this step and the evenness or the surface smoothness of the coat may be insufficient. On the other hand, if the temperature exceeds 130°C, the uncured electrodeposited coat may begin to cure before the coat has flown sufficiently, with the consequence that, after this step, pinholes may remain, the evenness of the coat be inadequate, or the surface smoothness of the coat be insufficient. The preferred range is 70 to 110°C. The heating time in said pre-baking step is not particularly restricted but from coat meltability and industrial points of view, it may for example be 2 to 30 minutes.
The activation energy beam irradiation step in the 5 method of forming an electrocoating film according to the present invention, which precedes the post-baking step, is intended to fix the coat surface which has been improved in evenness and smoothness by said pre-baking step. By carrying out this step, the reflow of the electrodeposited 10 coat is inhibited so that even when the electrodeposited coat is further heated and caused to cure thoroughly, the ultimate electrocoating film can be obtained with the high surface smoothness achieved in this step being successfully retained.
The activation energy beam which can be used includes ultraviolet light, X-rays, an electron beam, near-infrared light and visible light. The activation energy beam in the context of the present invention does not include heat-generating energy beams such as infrared light, high-frequency waves and microwaves. However, although near-infrared light is a heat-generating energy beam, it is included in said activation energy beam because there exist light-sensitive radical initiators showing initiating functions in this wavelength region.
For irradiation with ultraviolet light, there can be used a variety of light sources, such as a mercury arc lamp, a xenon arc lamp, a fluorescent lamp, a carbon arc lamp, a tungsten-halogen copier lamp, and so forth. On the other hand, as emission sources of an electron beam, there can be used electron beam generators such as Cockcroft type, Cockcroft-Walton type, van de Graaff type, resonance transformer type, transformer type, insulating core transformer type, Dynamitron type, linear filament type, high-frequency type, and other devices. It should be understood that when an electron beam is used, it is not always necessary to use a light-sensitive radical initiator.
The conditions of said irradiation with an activation energy beam in this step vary with the amount of unsaturation in the resin and the molecular weight of the resin in the electroCOating composition used but taking ultraviolet light as an example of said activation energy beam, its wavelength range may be 200 to 500 nm and the integrating radiation dosage may for example be 100 to 10000 mJ/Cm2 when the coating used contains a light-sensitive radical initiator or 1000 to 20000 mJ/Cm2 when the coating does not contain a light-sensitive radical initiator. When the integrating radiation dosage is insufficient, fixing of the electrodeposited coat surface is inadequate so that the ultimate electrocoating film tends to be deficient in smoothness. An excessive integrating radiation dosage would not cause any serious trouble but lead to a waste of energy. On the other hand, when an electron beam is used, it is advantageous to carry out the irradiation using an electron beam generator with an output energy of 50 to 500 ke~T for a predetermined time.
It is also recommendable to adjust the distance between the electrodeposited coat and the light source according to the shape of the work so as to provide for a uniform irradiation with the activation energy beam and bring said integrating radiation dosage and energy into a predetermined range.
The above activation energy beam irradiation step may be carried out directly following said pre-baking step without cooling the work between the steps.
The post-baking step in the method of forming an electroCOating film according to the present invention is intended to thermally cure the electrodeposited coat having a fixed surface following the activation energy beam irradiation step. By carrying out this step, the entirety of the electrodeposited Coat inclusive of its interior Can be caused to cure thoroughly. Although the electrodeposited coat undergoes remelting to flow in this step, the coat surface which has been hardened in the preceding step does not melt so that all ultimately cured electrocoating film can be produced with the high surface smoothness obtained in the preceding step being fully retained.
The heating conditions for use in this post-baking step are not particularly restricted provided that the electrocoating film having a fixed surface obtained after said pre-baking step and subsequent activation energy beam irradiation step can be thoroughly cured down to its interior. The above heating conditions can be appropriately established according to the kind of electrocoating composition used and, for example, the heating temperature may be 130 to X60°C. The heating time in this post-baking step is not particularly restricted, either, and may for example be 10 to 30 minutes.
The heating in this post-baking step may be a continuation of the heating in said pre-baking step.
The method of forming an electrocoating film according to the present invention is applicable to electrically conductive substrates and can be used to form electrocoating films on various metallic materials such as copper, iron, galvanized steel sheet, aluminum and so forth.
The electrocoating film of the present invention is formed by the above-described method of forming an electrocoating film, and having such. a film, the electrodeposited article of the present invention features very satisfactory dielectric properties and surface smoothness.
The method of forming a multilayer film according to the present invention may comprise applying an overcoat in superimposition on the cured electrocoating film described above. The overcoat is intended to protect and impart an attractive appearance to said electrocoating film or adding new functions to the multilayer film. The overcoat mentioned just above is not particularly restricted but includes, for example, those materials which can be caused to undergo a curing reaction by heating and/or irradiation with an activation energy beam. Among specific examples are those binders, among the binder components mentioned in the foregoing description of the electrocoating composition of the present invention, which can be cured by heating 1~ and/or irradiation with an activation energy beam. In the case of a non-aqueous one, the binder need not have an ionic group. As the skeleton of the binder component, there can be used an acrylic resin, polyester resin, epoxy resin, urethane resin, or the like and where flexibility is further required, these resins may have been modified by introducing a butadiene skeleton, siloxane skeleton or long-chain aliphatic skeleton.
In the case where the overcoat is heat-curable but cannot be cured in the presence of said binder component alone, a curing agent suited to the kind of said reactive functional group can be used as an auxiliary binder component. The curing agent mentioned just above includes amino resins and optionally blocked polyisocyanates.
In addition to said binder component or components, the above overcoat may contain a pigment, a resin particle, and various additives. For imparting electrical conductivity as a new function to the multilayer film, the above overcoat may be supplemented with a metal particle, carbon, metal oxide, and/or the like. For imparting high 3~ dielectric properties, glass fiber, ceramics, and so on may be formulated.
The coating method is not particularly restricted but includes the techniques well known to those skilled in the art, such as bar coating, die coating, spray coating, rotary atomizer coating, spin coating, and so forth. By curing the resulting film by heating and/or irradiation with an activation energy beam, an overcoat can be constructed. The heating conditions and the conditions of activation energy beam irradiation can be judiciously established according to the kind of overcoat used. The cured thickness of the above overcoat is not particularly restricted but may, for example, be 10 to 100 lam.
The application of the overcoat may be carried out in a few divided cycles.
The multilayer film of the present invention is the film obtained by the above-described method of forming a multilayer film, and the article according to this invention has said multilayer film and, therefore, features a high degree of smoothness.
BEST MODE FOR CARRYING OUT THE PRESENT INVENTION
The following examples are intended to illustrate the present invention in further detail without defining the scope of the present invention. In the examples, "part(s)"
means "part(s) by weight" unless otherwise specified.
Example 1 Using Insuleed 1004 (product of Nippon Paint Co., an electrolytically active electrocoating, melting temperature 90°C, curing temperature 180°C), a copper substrate (10 cm x 10 cm x 700 um thick) was electrodeposited at an electrodepositing voltage of 200 V for 1 minute in a dry film thickness of 20 um to give an uncured electrodeposited coat. The temperature of the electrodepositing bath was 30°C. After electrodepositing, the substrate was cleaned by dipping it in deionized water for 1 minute to remove the superfluous electrocoating composition on the substrate and electrodeposited coat.
Then, the substrate carrying this uncured electrodeposited coat was pre-baked in a heating oven at a set temperature of 90°C for 10 minutes. After completion of this pre-baking, the substrate was taken out from the oven and the electrodeposited coat on the substrate surface was visually examined. It was found that the coat had flown sufficiently to become smooth.
5 Then, using a high-pressure mercury-vapor lamp (peak wavelength 365 nm, irradiation intensity 50 mJ/(cm2~s)), the substrate was irradiated with ultraviolet light at an integrating radiation dosage of 10000 mJ/cm'.
Thereafter, the substrate was post-baked in a heating 10 oven at a set temperature of 180°C for 20 minutes to give an electrocoating film.
Example 2 A substrate having an uncured electrodeposited coat 15 as obtained in the same manner as in Example 1 was used as the work. Meanwhile, a device capable of effecting both heating and UV irradiation was set to a heating temperature of 90°C and, for UV irradiation, to a peak wavelength of 365 nm, an irradiation intensity of 50 mJ/(cm~~s) and an integrating radiation dosage of 10000 mJ/cm2. Using the above device, heating alone was carried out for 9 minutes.
Then, with the heating being further continued under the same conditions as above for 1 minute, the work was irradiated with UV light for 1 minute.
Thereafter, the work was caused to cure by the post-baking in a heating oven set to 180°C for 20 minutes to give an electrocoating film.
Example 3 Using CCR-232GF (product of Asahi Chemical Research Co., an epoxy resin overcoat), the electrocoating film obtained in Example 2 was spray-coated in a cured thickness of 25 um. Then the work was cured by heating at 150°C for 60 minutes to give a multilayer film.
Example 4 Using a coating material prepared by adding 1 part of Irgacure 651 (ben~yl dimethyl ketal, product of Chiba-Geigy, a light-sensitive radical initiator) to 100 parts resin solids of Insuleed 1004 in lieu of Insuleed 1004, the procedure of Example 1 was otherwise faithfully followed to give an uncured electrodeposited coat which had flown sufficiently t~ present with a smooth surface.
Then, except that the integrating radiation dosage of 1~ a high-pressure mercury vapor lamp was set t~ 200 mJ/Cm~, the work was post-baked in the same manner as in Example 1 to give an electrocoating film.
Comparative Example 1 Omitting the pre-baking and UV irradiation steps, the procedure of Example 1 was otherwise faithfully followed to give an electrocoating film.
Comparative Example 2 2~ Omitting the pre-baking step, the procedure of Example 1 was otherwise faithfully followed to give an electrocoating film.
Comparative Example 3 Omitting the UV irradiation step, the procedure of Example 1 was otherwise faithfully followed to give an electrocoating film.
<Evaluation Tests>
Smoothness Using SJ-201 (the surface roughness tester manufactured by Mitsutoyo Co.), the surface roughness Ra values of the electroCOating films obtained in Examples 1, 2 and 4 and in Comparative Examples 1-3 and the corresponding value of the multilayer film obtained in Example 3 were respectively measured. As measuring conditions, a cutoff point of 0.8 mm was used. The results are presented in Table 1.
Dielectric breakdown voltage The dielectric breakdown voltage values of the electrocoating films obtained in Examples 1, 2 and 4 and Comparative Examples 1 to 3 and the Corresponding value of the multilayer film obtained in Example 3 were respectively measured with Auto Tester lTodel 8525 (the breakdown voltage tester manufactured by Tsuruga Electric Co.). The results are presented in Table 1.
Table 1 Example Comparative Example Smoothness(um) 0.15 0.22 0.20 0.16 0.35 0.67 0.35 Dielectric 4.6 4.9 7.5 4.4 2.5 0.8 2.7 property (KV) It will be apparent from Table 1 that the electrocoating films (Examples 1, 2 and 4) obtained by the method of forming an electrocoating film according to the present invention and the multilayer film (Example 3) obtained by the method of forming a multilayer film according to the present invention are outstanding in smoothness and dielectric properties. However, the film obtained by omitting the pre-baking step (Comparative Example 2), the film obtained by omitting the pre-baking and activation energy beam irradiation steps (Comparative Example 1) and the film obtained by omitting the activation energy beam irradiation steps (Comparative Example 3) were inferior in surface smoothness and dielectric properties.
Then, except that the integrating radiation dosage of 1~ a high-pressure mercury vapor lamp was set t~ 200 mJ/Cm~, the work was post-baked in the same manner as in Example 1 to give an electrocoating film.
Comparative Example 1 Omitting the pre-baking and UV irradiation steps, the procedure of Example 1 was otherwise faithfully followed to give an electrocoating film.
Comparative Example 2 2~ Omitting the pre-baking step, the procedure of Example 1 was otherwise faithfully followed to give an electrocoating film.
Comparative Example 3 Omitting the UV irradiation step, the procedure of Example 1 was otherwise faithfully followed to give an electrocoating film.
<Evaluation Tests>
Smoothness Using SJ-201 (the surface roughness tester manufactured by Mitsutoyo Co.), the surface roughness Ra values of the electroCOating films obtained in Examples 1, 2 and 4 and in Comparative Examples 1-3 and the corresponding value of the multilayer film obtained in Example 3 were respectively measured. As measuring conditions, a cutoff point of 0.8 mm was used. The results are presented in Table 1.
Dielectric breakdown voltage The dielectric breakdown voltage values of the electrocoating films obtained in Examples 1, 2 and 4 and Comparative Examples 1 to 3 and the Corresponding value of the multilayer film obtained in Example 3 were respectively measured with Auto Tester lTodel 8525 (the breakdown voltage tester manufactured by Tsuruga Electric Co.). The results are presented in Table 1.
Table 1 Example Comparative Example Smoothness(um) 0.15 0.22 0.20 0.16 0.35 0.67 0.35 Dielectric 4.6 4.9 7.5 4.4 2.5 0.8 2.7 property (KV) It will be apparent from Table 1 that the electrocoating films (Examples 1, 2 and 4) obtained by the method of forming an electrocoating film according to the present invention and the multilayer film (Example 3) obtained by the method of forming a multilayer film according to the present invention are outstanding in smoothness and dielectric properties. However, the film obtained by omitting the pre-baking step (Comparative Example 2), the film obtained by omitting the pre-baking and activation energy beam irradiation steps (Comparative Example 1) and the film obtained by omitting the activation energy beam irradiation steps (Comparative Example 3) were inferior in surface smoothness and dielectric properties.
INDUSTRIAL APPLICABILITY
The method of forming an electrocoating film according to the present invention comprises a pre-baking step and an activation energy beam irradiation step which are carried out in that order prior to a post-laaking step, with the result that the resulting electrocoating film is outstanding in surface smoothness and dielectric properties.
Moreover, the method of forming a multilayer film according to the present invention comprises applying an overcoat in superimposition on the electrocoating film obtained by said method of forming an electrocoating film and the resulting multilayer film is also outstanding in surface smoothness and dielectric properties.
The underlying principle of these methods is that the surface roughness of the uncured coat formed by electrodepositing and the pinholes existing in the coat can be reduced or eliminated by the pre-baking step which causes the uncured electrodeposited coat to melt and flow, thus providing for evenness and smoothness, the film surface is then fixed to preserve said evenness and smoothness by irradiation with an activation energy beam and, thereafter, the entirety of the coat is cured by post-baking.
The method of forming an electrocoating film according to the present invention and the method of forming a multilayer film according to the present invention provide an electrocoating film and a multilayer film, both having every satisfactory surface smoothness and dielectric properties and, thus, finding application in various kinds of electronic and electric equipment.
The method of forming an electrocoating film according to the present invention comprises a pre-baking step and an activation energy beam irradiation step which are carried out in that order prior to a post-laaking step, with the result that the resulting electrocoating film is outstanding in surface smoothness and dielectric properties.
Moreover, the method of forming a multilayer film according to the present invention comprises applying an overcoat in superimposition on the electrocoating film obtained by said method of forming an electrocoating film and the resulting multilayer film is also outstanding in surface smoothness and dielectric properties.
The underlying principle of these methods is that the surface roughness of the uncured coat formed by electrodepositing and the pinholes existing in the coat can be reduced or eliminated by the pre-baking step which causes the uncured electrodeposited coat to melt and flow, thus providing for evenness and smoothness, the film surface is then fixed to preserve said evenness and smoothness by irradiation with an activation energy beam and, thereafter, the entirety of the coat is cured by post-baking.
The method of forming an electrocoating film according to the present invention and the method of forming a multilayer film according to the present invention provide an electrocoating film and a multilayer film, both having every satisfactory surface smoothness and dielectric properties and, thus, finding application in various kinds of electronic and electric equipment.
Claims (10)
1. A method of forming an electrocoating film comprising coating a work with an electrocoating composition curable by heating and irradiation with an activation energy beam in which an electrodepositing step, an aqueous cleaning step, a pre-baking step, an activation energy beam irradiation step, and a post-baking step are serially carried out in the order mentioned.
2. The method of forming an electrocoating film according to Claim 1, wherein said activation energy beam irradiation step is carried out directly following said pre-baking step without cooling the work.
3. The method of forming an electrocoating film according to Claim 1 or 2, wherein the heating in said post-baking step is continuous from said pre-baking step.
4. The method of forming an electrocoating film according to any of Claims 1 to 3, wherein said electrocoating composition comprises a resin composition containing sulfonium and propargyl groups.
5. The method of forming an electrocoating film according to any of Claims 1 to 4, wherein said electrocoating composition is a cationic electrocoating composition.
6. An electrocoating film which is formed by the method of forming an electrocoating film according to any of Claims 1 to 5.
7. An electrodeposited article having the electrocoating film according to Claim 6.
8. A method of forming a multilayer film in which the electrocoating film according to Claim 6 is further coated with an overcoat.
9. A multilayer film which is formed by the method of forming a multilayer film according to Claim 8.
10. An article hawing the multilayer film according to Claim 9.
Applications Claiming Priority (3)
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JP2003081890 | 2003-03-25 | ||
JP2003-081890 | 2003-03-25 | ||
PCT/JP2004/004176 WO2004085713A1 (en) | 2003-03-25 | 2004-03-25 | Method of forming an electrocoating film, electrocoating film, and electrodeposited article |
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CA2515806A1 true CA2515806A1 (en) | 2004-10-07 |
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CA002515806A Abandoned CA2515806A1 (en) | 2003-03-25 | 2004-03-25 | Method of forming an electrocoating film, electrocoating film, and electrodeposited article |
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US (1) | US20070000783A1 (en) |
JP (1) | JP2006523776A (en) |
CA (1) | CA2515806A1 (en) |
DE (1) | DE112004000494T5 (en) |
GB (1) | GB2414244B (en) |
TW (1) | TW200420360A (en) |
WO (1) | WO2004085713A1 (en) |
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JP4894952B2 (en) * | 2009-09-10 | 2012-03-14 | トヨタ車体株式会社 | Hinge for vehicle door |
TWI462782B (en) * | 2009-12-10 | 2014-12-01 | Hon Hai Prec Ind Co Ltd | Method for spraying coating |
Family Cites Families (11)
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US4083763A (en) * | 1968-07-08 | 1978-04-11 | Nippon Steel Corporation | Method for manufacturing colored metal sheets |
US3971708A (en) * | 1971-07-08 | 1976-07-27 | Scm Corporation | Electrocoating process |
JPS5461246A (en) * | 1977-10-25 | 1979-05-17 | Kansai Paint Co Ltd | Electrodeposit coating |
AT377774B (en) * | 1980-12-18 | 1985-04-25 | Vianova Kunstharz Ag | METHOD FOR PAINTING CONDUCTIVE OBJECTS |
US4924974A (en) * | 1989-01-11 | 1990-05-15 | Inventio Ag | Elevator system having hall lantern assembly for elevator car door post of hatch door post |
JP3192197B2 (en) * | 1992-03-23 | 2001-07-23 | 株式会社シミズ | UV curable cationic electrodeposition coating composition for plating materials |
EP1144520B1 (en) * | 1998-12-10 | 2004-04-28 | E.I. DU PONT DE NEMOURS & COMPANY INCORPORATED | Aqueous electrodeposition coating, the production and use thereof |
JP2000189891A (en) * | 1998-12-28 | 2000-07-11 | Nippon Paint Co Ltd | Method for forming double-layered coating film, method for forming multi-layered coating film, and multilayered coating film obtained by the method |
JP2002265882A (en) * | 2001-03-15 | 2002-09-18 | Nippon Paint Co Ltd | Cationic electrodeposition coating composition, method for forming film and coated product having film |
JP3984488B2 (en) * | 2001-03-27 | 2007-10-03 | 日本ペイント株式会社 | Curable coating composition and coating film forming method |
JP4393160B2 (en) * | 2002-11-26 | 2010-01-06 | 関西ペイント株式会社 | Cationic coating composition and coating film forming method |
-
2004
- 2004-03-24 TW TW093107865A patent/TW200420360A/en unknown
- 2004-03-25 DE DE112004000494T patent/DE112004000494T5/en not_active Withdrawn
- 2004-03-25 US US10/551,125 patent/US20070000783A1/en not_active Abandoned
- 2004-03-25 CA CA002515806A patent/CA2515806A1/en not_active Abandoned
- 2004-03-25 JP JP2006507688A patent/JP2006523776A/en active Pending
- 2004-03-25 GB GB0517495A patent/GB2414244B/en not_active Expired - Fee Related
- 2004-03-25 WO PCT/JP2004/004176 patent/WO2004085713A1/en active Application Filing
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GB0517495D0 (en) | 2005-10-05 |
TW200420360A (en) | 2004-10-16 |
GB2414244B (en) | 2006-09-27 |
US20070000783A1 (en) | 2007-01-04 |
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GB2414244A (en) | 2005-11-23 |
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