WO2001068778A1 - Coating composition for forming insulating films, non-oriented electrical steel sheet with the coating composition coated thereon, and method for forming the insulating films on the steel sheet - Google Patents

Coating composition for forming insulating films, non-oriented electrical steel sheet with the coating composition coated thereon, and method for forming the insulating films on the steel sheet Download PDF

Info

Publication number
WO2001068778A1
WO2001068778A1 PCT/KR2000/001414 KR0001414W WO0168778A1 WO 2001068778 A1 WO2001068778 A1 WO 2001068778A1 KR 0001414 W KR0001414 W KR 0001414W WO 0168778 A1 WO0168778 A1 WO 0168778A1
Authority
WO
WIPO (PCT)
Prior art keywords
coating composition
steel sheet
electrical steel
oriented electrical
coated
Prior art date
Application number
PCT/KR2000/001414
Other languages
French (fr)
Inventor
Young-Jong Yoo
Sam-Kyu Chang
Seok-Joo Lee
Original Assignee
Pohang Iron & Steel Co., Ltd.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to US09/980,942 priority Critical patent/US6667105B1/en
Application filed by Pohang Iron & Steel Co., Ltd. filed Critical Pohang Iron & Steel Co., Ltd.
Priority to DE60012191T priority patent/DE60012191D1/en
Priority to EP00983516A priority patent/EP1208166B1/en
Priority to JP2001567265A priority patent/JP3546040B2/en
Publication of WO2001068778A1 publication Critical patent/WO2001068778A1/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/16—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets
    • H01F1/18—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets with insulating coating
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B19/00—Apparatus or processes specially adapted for manufacturing insulators or insulating bodies
    • H01B19/04—Treating the surfaces, e.g. applying coatings
    • 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
    • C09D125/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Coating compositions based on derivatives of such polymers
    • C09D125/02—Homopolymers or copolymers of hydrocarbons
    • C09D125/04—Homopolymers or copolymers of styrene
    • C09D125/08—Copolymers of styrene
    • 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
    • C09D5/08—Anti-corrosive paints
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1277—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a particular surface treatment
    • C21D8/1283—Application of a separating or insulating coating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31678—Of metal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31678—Of metal
    • Y10T428/31692—Next to addition polymer from unsaturated monomers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31678—Of metal
    • Y10T428/31692—Next to addition polymer from unsaturated monomers
    • Y10T428/31696—Including polyene monomers [e.g., butadiene, etc.]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31678—Of metal
    • Y10T428/31692—Next to addition polymer from unsaturated monomers
    • Y10T428/31699—Ester, halide or nitrile of addition polymer

Definitions

  • the present invention relates to a coating composition for forming insulating films, a non-oriented electrical steel sheet with the coating composition coated thereon, and a method for forming the insulating films on the steel sheet . More specifically the present invention relates to an organic-inorganic mixed coating composition for forming insulating films, a non-oriented electrical steel sheet with the coating composition coated thereon, and a method for forming the insulating films on the steel sheet, in which the roll spreading workability and the films characteristics are superior, and the aesthetics is excellent.
  • the non-oriented electrical steel sheets are used as the steel core for small electric motors and for transformers. These non-oriented electrical steel sheets are coatedwith insulating films before being supplied to users, so that the power loss due to the generation of the eddy currents can be minimized.
  • the non-orientedelectrical steel sheets whichare supplied to the users after forming the insulating films are generally made to undergo further processes such as punching, high temperature annealing for relieving the stress, automatic stacking, welding and the like so as to provide a shape to the steel sheets .
  • the insulating films should not be peeled off, and should be highly heat resistant so as to maintain the insulating properties even at a high temperature.
  • the non-oriented electrical steel sheets are directly supplied to the users after forming the insulating films, and therefore, the aesthetics of the steel sheets has to be superior. Besides, it is required that the adherence, corrosion resistance and continuous roll spreading workability be superior .
  • the conventional insulating films which are coated on the non-oriented electrical steel sheets are roughly classified into: organic ones, inorganic ones, and organic-inorganic mixed ones.
  • the inorganic insulating films are superior in the heat resistance compared with the organic and organic-inorganic mixed insulating films, but the punchability is not adequate.
  • the organic insulating films are superior in the punchability and the adherence, but the films are decomposed and destroyed during the stress relieving annealing, with the result that the adherence is aggravated.
  • the composition of the organic-inorganic mixed insulating films generally contain chromic acid so as to ensure the requisite characteristics such as corrosion resistance, adherence and the like. Chromic acid thus contained not only gives harmful effects to the human bodies during the manufacture of the coating composition and during the coating operation, but also brings environmental contamination such as water contamination and the like. Accordingly, there has been researched and developed an insulating film which does not contain the chrome compound, and one of this is Japanese Patent Application Laid-open No. Hei-6-330338.
  • the main ingredient is an emulsion of primary aluminum phosphate and an organic resin having a particle size of
  • the particle size of the organic resin is controlled so that the heat resistance and the like can be improved.
  • the chrome compound is excluded are Japanese Patent Application Laid-open No. Hei-7-41913 and He-7-166365.
  • the main ingredients are an organic resin of a particle size of 0.3-3.0 ⁇ m and one or two selected from the group consisting of: aluminum phosphate, calcium phosphate and zinc phosphate. Further, there is added boric acid.
  • the above techniques do not contain the chrome compound, and therefore, the films are said to be environmentphilic as well as being not harmful to the human bodies, but their aesthetics are not desirable.
  • the present invention is intended to overcome the above described disadvantages of the conventional techniques .
  • an object of the present invention to provide an organic-inorganic mixed coating composition for forming an insulating film, in which the main ingredient is a phosphate and an acid-soluble emulsion type acrylic-styrenic copolymer, and there are further added the optimum amounts of elements for improving the coating characteristics , therebymaking the roll spreadingworkability, the film characteristics and the aesthetics superior, as well as preventing the environment from being contaminated.
  • the conventional coating compositions m which the chrome compound is used are not only harmful to the human bodies and but also undesirable environmentally. Therefore, there have been developed the organic-inorganic mixed coating compositions in which the use of the chrome compound is excluded. However, there is a limit to forming a reliable insulating film having superior film characteristics . Accordingly, the present inventors carried out repeated researches and studies to develop an organic-inorganic coating composition m which the use of the chrome compound is excluded, but m which superior film characteristics can be obtained.
  • the inventors found that there can be obtained superior film characteristics if the main ingredients are composed of organic-inorganic mixed substances consisting of a phosphate and a low foamable and acid-soluble emulsion-type acrylic-styrenic copolymer resin, and f additives such as zinc nitrate, silicon, anon-ionic surfactant , andethyleneglycol are addedinproperamounts .
  • the present invention came to be proposed.
  • the above citedadditives are added in proper amounts to the main ingredients composed of organic-inorganic mixed substances consisting of a phosphate and a low foamable and acid-soluble emulsion-type acrylic-styrenic copolymer resin, this being the principal feature of the present invention.
  • the respective additives act to solidify the phosphate and the acrylic resin, and act to form an insoluble film of a superior aesthetics.
  • the superior film characteristics and continuous roll spreading workability cannot be obtained by simply the respective additives.
  • the coating composition according to the present invention includes for each 100 g of phosphoric acid of a primary aluminum phosphate solution: 28-98 g (solid weight) of an acid-soluble emulsion type acrylic-styrenic copolymer resin; 6-18 g of zinc nitrate; 4-13 g of a silicon additive; 18-35 g of ethylene glycol; and 3-11 g of non-ionic surfactant.
  • phosphoric acid of a primary aluminum phosphate solution 28-98 g (solid weight) of an acid-soluble emulsion type acrylic-styrenic copolymer resin; 6-18 g of zinc nitrate; 4-13 g of a silicon additive; 18-35 g of ethylene glycol; and 3-11 g of non-ionic surfactant.
  • the methodforcoatingtheinsulatingfilmaccordingtothepresentinvention includes the steps of: preparing a coating composition by adding the above stated ingredients; spreading the coating composition on a non-oriented electrical steel sheet; and subjecting the electrical steel sheet (thus coated) to a heat treatment at a temperature of 150 - 800°C for 14-45 seconds .
  • the primary aluminum phosphate solution is for improving the heat resistance and the corrosion resistance of the coated film, and this can be prepared by adding aluminum hydroxide (which is a 3-valence metal compound) to phosphoric acid and making it dissolved.
  • aluminum hydroxide which is a 3-valence metal compound
  • the manufacturing method and the addition ratio between them are not specially limited.
  • the phosphoric acid may be the usual one, and the concentration should be preferably 85%.
  • the acrylic-styrenic copolymer resin which is used in the organic-inorganic mixedcoating composition shouldbe acid-soluble, so that the uniformity of the spreading of the composition can be improved through the combination stability and a low viscosity of the emulsion.
  • the acid-soluble emulsion type acrylic-styrenic copolymer resin shouldhave preferably a pHvalue of 4 or less, andmore preferably the resin should consists of: 35% of an acrylic compound and 65% of a styrenic compound, while their average particle size should be about 0.2 ⁇ m.
  • the acid-soluble emulsion type acrylic-styrenic copolymer resin acts to improve the adherence to the steel sheet, and the flexibility of the coated film.
  • the powderizing and the surface roughness are aggravated, thereby degrading the aesthetics.
  • the adherence cannot be strengthened, with the result that the addition effect cannot be expected.
  • the acid-soluble emulsion type acrylic-styrenic copolymer resin is limited to 28-98 g for each 100 g of phosphoric acid.
  • the content of zinc nitrate is limited to 6-18 g for each 100 g of phosphoric acid.
  • the users may judge that the quality has been deteriorated. If there is no color, then the users may judge that there has been done no coating. Therefore, it is the current trend that the appearance quality such as the color, the uniformity and the shining are also managed attentively.
  • the coating composition does not contain the chrome compound, but gives a film color which is similar to that of the conventional insulating films .
  • a separate pigment to the organic-inorganic mixed compositionforcontrolling the colorof the film, a light green-yellow color can be produced.
  • a specific reason is not apparent , but the reason can be conj ectured to be as follows .
  • the coating solution which is prepared by adding the resm into the zinc nitrate aqueous solution shows the milky color at the initial stage.
  • the resm component of the coating solution is reacted with the inorganic component of the oxide layer of the steel sheet (the oxide layer having been formed before) to form a new composite material during the process of oxidation of the zinc ions at above the boiling point of zinc nitrate so as to form zinc oxide.
  • This new composite material turns the color of the film to light green-yellow
  • the silicon additive is the polyester-transformed polyxyloxanic silicon. This lowers the surface tension of the coating solution, so that the moisture state of the steel sheet canbe improved.
  • a preferable example of this is the commodity model BYK-348 of BYK Chemie company of Germany.
  • the content of the silicon additive is limited to 4-13 g per 100 g of phosphoric acid within the solution. If the content is less than 4 g, then the addition effect does not appear, with the result that the moisture state of the steel sheet becomes insufficient . On the otherhand, if it exceeds 13 g, the aesthetics is aggravated.
  • the ethylene glycol acts to improve the external appearance by preventing the motley effect on the surface of the coiled steel sheet .
  • motley patterns appear very frequently on the surface of the coiled steel sheet This is due to the fact that when carrying out a heating at a relatively high temperature of 500 - 600°C, the material component having a boiling point of 100°C is evaporated earlier than the other volatile components of the coating material . Accordingly, if ethylene glycol which has a boiling point higher than that of water is added in the optimum amount, then the motley effect can be prevented even during a long time operation. Consequently, a uniform external appearance can be obtained.
  • the content of ethylene glycol is limited to 18-35 g per 100 g of phosphoric acid. If the content is less than 18 g, the aesthetic characteristics become insufficient, while if it exceeds 35 g, it does not completely evaporate even after the dryingbut partlyremains, with the result that the corrosion resistance and the water resistance are aggravated due to the hydroxyl group.
  • the non-ionic surfactant is added for improving the continuous roll spreading workability, and a preferable example of this is the commodity model TRITON X-405 of Union Carbide company of the U.S.
  • the pressing between the rolls causes the temperature torise, andtherefore, thewatercomponent of the coating solution is evaporated. Accordingly, the phosphate and the resin components are dried fast to be transited from the liquid phase to the solidphase, with the result that a stickingproperty is generated, and it cannot be reversed to the water-soluble property.
  • the non-ionic surfactant is added.
  • the properties of the coating solution is altered around the rolls so as to be led to have a sticking property and so as for the solidified solution to be adhered on the surface of the rolls in thick layers, to the degree that the operation becomes impossible.
  • the content exceeds 11 g, then foams are severely producedwithinthe treating fluid, withthe result that the aesthetics of the coated film is aggravated.
  • the content of the non-ionic surfactant per 100 g of phosphoric acid is limited to 3-11 g.
  • the coating solution is left for several days without use, and thus if the coating solution is brought to be used thereafter, the coating solution might have lost the spreadability due to the fact that during the leaving of the several days , a gel reactionhas occurredbetween the inorganic chrome component and the resin component .
  • the present invention also provides a non-oriented electrical steel sheet on which the above described coating composition is coated.
  • the coating composition is spread to a thickness of 0.7 - 2.8 ⁇ m on each face of the steel sheet. If the coated thickness is less than 0.7 ⁇ m, then the desired insulating strength cannot be obtained, while if it exceeds 2.8 ⁇ m, then a welding problem or the like may occur.
  • the present invention also provides a method for forming an insulating film by coating the above described coating composition.
  • the present invention water is added to the above described coating composition to form a coating solutionof the optimumconcentration.
  • the present invention is not limited to a particular concentration of the coating solution.
  • the above described coating solution is spread on the surface of the non-oriented electrical steel sheet.
  • the dried coated thickness should be 0.7 ⁇ 2.8 ⁇ m, and this range ensures the insulating strength and the weldability.
  • the non-oriented electrical steel sheet thus coated is annealed at a temperature of 150 - 800°C for 14 - 45 seconds, thereby obtaining an insulating film of superior characteristics .
  • This heat treatment temperature (the temperature of the heat treatment furnace) and the heat treatment time act as factors for deciding the film characteristics .
  • the heat treatment temperature is limited to 150 - 800°C. If the temperature is below 150°C, the heat treatment becomes insufficient, with the result that the moisture remains, or that even if a coated film is formed, the productivity is aggravated. On the other hand, if the temperature exceeds 800°C, the control of the heat treatment temperature becomes difficult, with the result that not only non-uniform coating is done, but also an appearance defect is produced.
  • the heat treatment time is limited to 14 - 45 seconds. If the heat treatment is carried out for less than 14 seconds at the highest allowable temperature of 800°C, the heat treatment becomes imperfect, with the result that the moisture remains . On the other hand, if the heat treatment is carriedout formore than45 seconds at theminimumallowable temperature of 150°C, then the coating material which has been chemically bonded with the oxide layer is oxidized, with the result that the color of the film is turned to black-brown to black, thereby generating color defects .
  • the heat treatment is carried out to a a temperature of 550 - 750°C for 18-37 seconds
  • the present invention provides an organic-inorganic mixed coating composition in which the roll spreadability and the insulating film characteristics are superior.
  • the present invention provides a non-oriented electrical steel sheet coated with the above coating composition, in which the aesthetics, the adherence, the corrosion resistance and the weldability are superior.
  • Coating compositions for forming insulating films were prepared by varying the compositions as shown in Table 1 below for each 100 g of phosphoric acid of a primary aluminum phosphate solution
  • this coating compositions were aged for 3 days. Then these coating compositions were spreadonnon-orientedelectrical steel sheets (0.5 mm thick, and containing 1.0% of Si) . Then these coatedsteel sheetsweremade toundergoaheat treatment at atemperature of 550°C for 30 seconds, and thus, non-oriented electrical steel sheets were obtained on which insulating films of a thickness of about 2.1 ⁇ m were coated respectively.
  • the corrosionresistance was classified into: the case where the generation of rust was absent on the surface of the insulating film; the case where the generation of rust was present partly, and the case where the generation of rust was widely prevalent. These cases were indicated by 0, ⁇ and x respectively. Further, as to the peeling of the films, the case where the peeling was absent was indicated by 0, and the case where the peeling was present was indicated by x. Further, the case where the aesthetics was superior was indicated by 0, and the case where aesthetics was inferior was indicated by x. ⁇ Table 1>
  • CD indicates emulsion type acrylic-styrenic
  • non-ionic surfactant (TRITON X-405) , ® indicates ethylene glycol,
  • the corrosion resistance was evaluated by visually observing the presence or absence of rust when the coated steel sheets were left indoor for one year and exposed outdoor for three months.
  • Example 2 A film coating composition which was composed like that of the inventive example 1 of Example 1 was aged for 3 days. This coating composition was uniformly spread on non-oriented electrical steel sheets (0.5 mm thick, and containing 1.0% of Si by varying the coating thickness. Then the test pieces were annealed at 550°C for 30 seconds, and thus, the coated films were various as shown in Table 3 below.
  • the non-oriented electrical steel sheets on which the coated films were different in the thickness were measured as to their film characteristics suchas insulating strength, corrosion measured by applying the TIG welding (welding current: 150 A, electrode: pure-W (3,2 mm ⁇ ), electrode gap: 0.35 mm, and the welding speed: 15 mm/sec) , and that the external appearance of the bead part after the welding and the generation of blow holes were visually observed.
  • TIG welding welding current: 150 A, electrode: pure-W (3,2 mm ⁇ ), electrode gap: 0.35 mm, and the welding speed: 15 mm/sec
  • a coating composition which was composed like that of the inventive example 2 of Example 1 was prepared, and it was aged for three days. This composition was coated on non-oriented electrical steel sheets (0.5 mm thick) uniformly and continuously. Then these test pieces were annealed at various heat treatment conditions as shown m Table 4 below, thereby manufacturing non-oriented electrical steel sheets .
  • the insulating film was thick to the value of about 2.3 ⁇ m, and the film characteristics were superior.
  • the film characteristics such as aesthetics, insulating strength, heat resistance and the like are superior. Further, the contamination of the nature can be prevented, and the coated film are immune from property degradations after elapsing of time.
  • the organic-inorganic mixed coating composition of the present invention is useful to manufacturing the non-oriented electrical steel sheet.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Thermal Sciences (AREA)
  • Metallurgy (AREA)
  • Electromagnetism (AREA)
  • Mechanical Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Power Engineering (AREA)
  • Chemical Treatment Of Metals (AREA)
  • Paints Or Removers (AREA)
  • Manufacturing Of Steel Electrode Plates (AREA)
  • Laminated Bodies (AREA)

Abstract

A coating composition for forming insulating films, a non-oriented electrical steel sheet with the coating composition coated thereon, and a method for forming the insulating films on the steel sheet, are disclosed. The coating composition includes the following ingredients for each 100 g of phosphoric acid of a primary aluminum phosphate solution. That is, they are 28∼98 g (solid weight) of an acid-soluble emulsion type acrylic-styrenic copolymer resin, 6∼18 g of zinc nitrate, 4∼13 g of a silicon additive, 18∼35 g of ethylene glycol, and 3∼11 g of non-ionic surfactant. The non-oriented electrical steel sheet is coated with the above coating composition. The coating composition is superior in the roll coating workability and in the film characteristics, and further, it is environmentphilic and has a superior aesthetics.

Description

COATING COMPOSITION FOR FORMING INSULATING FILMS, NON-ORIENTED ELECTRICAL STEEL SHEET WITH THE COATING COMPOSITION COATED THEREON, AND METHOD FOR FORMING THE INSULATING FILMS ON THE STEEL SHEET
FIELD OF THE INVENTION
The present invention relates to a coating composition for forming insulating films, a non-oriented electrical steel sheet with the coating composition coated thereon, and a method for forming the insulating films on the steel sheet . More specifically the present invention relates to an organic-inorganic mixed coating composition for forming insulating films, a non-oriented electrical steel sheet with the coating composition coated thereon, and a method for forming the insulating films on the steel sheet, in which the roll spreading workability and the films characteristics are superior, and the aesthetics is excellent.
BACKGROUND OF THE INVENTION
Generally, the non-oriented electrical steel sheets are used as the steel core for small electric motors and for transformers. These non-oriented electrical steel sheets are coatedwith insulating films before being supplied to users, so that the power loss due to the generation of the eddy currents can be minimized.
The non-orientedelectrical steel sheetswhichare supplied to the users after forming the insulating films are generally made to undergo further processes such as punching, high temperature annealing for relieving the stress, automatic stacking, welding and the like so as to provide a shape to the steel sheets .
During the high temperature annealing for relieving the stress, the insulating films should not be peeled off, and should be highly heat resistant so as to maintain the insulating properties even at a high temperature. Further, the non-oriented electrical steel sheets are directly supplied to the users after forming the insulating films, and therefore, the aesthetics of the steel sheets has to be superior. Besides, it is required that the adherence, corrosion resistance and continuous roll spreading workability be superior .
The conventional insulating films which are coated on the non-oriented electrical steel sheets are roughly classified into: organic ones, inorganic ones, and organic-inorganic mixed ones.
The inorganic insulating films are superior in the heat resistance compared with the organic and organic-inorganic mixed insulating films, but the punchability is not adequate. The organic insulating films are superior in the punchability and the adherence, but the films are decomposed and destroyed during the stress relieving annealing, with the result that the adherence is aggravated.
Accordingly, there has been demanded for the development of organic-inorganic mixed insulating films which have the merits of the inorganic insulating films and the organic insulating films. Examples of this are Korean Patents 25106, 31208 and 31219.
The composition of the organic-inorganic mixed insulating films generally contain chromic acid so as to ensure the requisite characteristics such as corrosion resistance, adherence and the like. Chromic acid thus contained not only gives harmful effects to the human bodies during the manufacture of the coating composition and during the coating operation, but also brings environmental contamination such as water contamination and the like. Accordingly, there has been researched and developed an insulating film which does not contain the chrome compound, and one of this is Japanese Patent Application Laid-open No. Hei-6-330338.
In this technique, the main ingredient is an emulsion of primary aluminum phosphate and an organic resin having a particle size of
0.3-3.0 μm. Further, there are added boric acid and colloidal silica.
Particularly, the particle size of the organic resin is controlled so that the heat resistance and the like can be improved.
Other examples in which the chrome compound is excluded are Japanese Patent Application Laid-open No. Hei-7-41913 and He-7-166365. In these cases, the main ingredients are an organic resin of a particle size of 0.3-3.0 μm and one or two selected from the group consisting of: aluminum phosphate, calcium phosphate and zinc phosphate. Further, there is added boric acid. The above techniques do not contain the chrome compound, and therefore, the films are said to be environmentphilic as well as being not harmful to the human bodies, but their aesthetics are not desirable.
SUMMARY OF THE INVENTION
The present invention is intended to overcome the above described disadvantages of the conventional techniques .
Therefore it is an object of the present invention to provide an organic-inorganic mixed coating composition for forming an insulating film, in which the main ingredient is a phosphate and an acid-soluble emulsion type acrylic-styrenic copolymer, and there are further added the optimum amounts of elements for improving the coating characteristics , therebymaking the roll spreadingworkability, the film characteristics and the aesthetics superior, as well as preventing the environment from being contaminated.
It is another object of the present invention to provide a non-oriented electrical steel sheet m which the coating composition composed of the ingredients is coated thereon, and therefore, the insulating properties of the coated film are superior, and the aesthetics is excellent.
It is still another object of the present invention to provide a method for forming the insulating films on the non-oriented electrical steel sheet, m which the properties same as mentioned above are obtained
The conventional coating compositions m which the chrome compound is used are not only harmful to the human bodies and but also undesirable environmentally. Therefore, there have been developed the organic-inorganic mixed coating compositions in which the use of the chrome compound is excluded. However, there is a limit to forming a reliable insulating film having superior film characteristics . Accordingly, the present inventors carried out repeated researches and studies to develop an organic-inorganic coating composition m which the use of the chrome compound is excluded, but m which superior film characteristics can be obtained. As a result, the inventors found that there can be obtained superior film characteristics if the main ingredients are composed of organic-inorganic mixed substances consisting of a phosphate and a low foamable and acid-soluble emulsion-type acrylic-styrenic copolymer resin, and f additives such as zinc nitrate, silicon, anon-ionic surfactant , andethyleneglycol are addedinproperamounts . Thus the present invention came to be proposed.
That is, in the present invention, the above citedadditives are added in proper amounts to the main ingredients composed of organic-inorganic mixed substances consisting of a phosphate and a low foamable and acid-soluble emulsion-type acrylic-styrenic copolymer resin, this being the principal feature of the present invention. Thus when the coating composition is spread on the electrical steel sheet, the respective additives act to solidify the phosphate and the acrylic resin, and act to form an insoluble film of a superior aesthetics. The superior film characteristics and continuous roll spreading workability cannot be obtained by simply the respective additives.
In achieving the above objects, the coating composition according to the present invention includes for each 100 g of phosphoric acid of a primary aluminum phosphate solution: 28-98 g (solid weight) of an acid-soluble emulsion type acrylic-styrenic copolymer resin; 6-18 g of zinc nitrate; 4-13 g of a silicon additive; 18-35 g of ethylene glycol; and 3-11 g of non-ionic surfactant. Inanotheraspect of thepresent invention, thenon-oriented electrical steel sheet according to the present invention is coated with the above coating composition.
In still another aspect of the present invention, the methodforcoatingtheinsulatingfilmaccordingtothepresentinvention includes the steps of: preparing a coating composition by adding the above stated ingredients; spreading the coating composition on a non-oriented electrical steel sheet; and subjecting the electrical steel sheet (thus coated) to a heat treatment at a temperature of 150 - 800°C for 14-45 seconds .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First, the coating composition for forming an insulating film will be described.
The primary aluminum phosphate solution is for improving the heat resistance and the corrosion resistance of the coated film, and this can be prepared by adding aluminum hydroxide (which is a 3-valence metal compound) to phosphoric acid and making it dissolved. In the present invention, the manufacturing method and the addition ratio between them are not specially limited. The phosphoric acid may be the usual one, and the concentration should be preferably 85%.
The acrylic-styrenic copolymer resin which is used in the organic-inorganic mixedcoating composition shouldbe acid-soluble, so that the uniformity of the spreading of the composition can be improved through the combination stability and a low viscosity of the emulsion.
The acid-soluble emulsion type acrylic-styrenic copolymer resin shouldhave preferably a pHvalue of 4 or less, andmore preferably the resin should consists of: 35% of an acrylic compound and 65% of a styrenic compound, while their average particle size should be about 0.2 μm.
In the present invention, the acid-soluble emulsion type acrylic-styrenic copolymer resin acts to improve the adherence to the steel sheet, and the flexibility of the coated film. However, if its content is too low, then the powderizing and the surface roughness are aggravated, thereby degrading the aesthetics. Further, the adherence cannot be strengthened, with the result that the addition effect cannot be expected. On the other hand, if its content is too excessive, then the insulating properties and the heat resistance are aggravated after the stress relieving heat treatment . Therefore, in the present invention, the acid-soluble emulsion type acrylic-styrenic copolymer resin is limited to 28-98 g for each 100 g of phosphoric acid.
Meanwhile, if zinc nitrate is less than 6 g for each 100 g of phosphoric acid of the phosphate solution, the aesthetics such as color and shining are aggravated, while if it exceeds 18 g, the coated film canbe peeled off after the stress relieving heat treatment .
Therefore, in the present invention, the content of zinc nitrate is limited to 6-18 g for each 100 g of phosphoric acid.
In the conventional coating solution in which the chrome compound is contained, a reduction reaction of the 6-valence chrome is done, and therefore, the color of the coated film is light-green.
Therefore, in the case where the color of the coated film is markedly different from the conventional color, then the users may judge that the quality has been deteriorated. If there is no color, then the users may judge that there has been done no coating. Therefore, it is the current trend that the appearance quality such as the color, the uniformity and the shining are also managed attentively.
In the present invention, the coating composition does not contain the chrome compound, but gives a film color which is similar to that of the conventional insulating films . In other words, without adding a separate pigment to the organic-inorganic mixed compositionforcontrolling the colorof the film, a light green-yellow color can be produced. For this phenomenon, a specific reason is not apparent , but the reason can be conj ectured to be as follows .
That is, the coating solution which is prepared by adding the resm into the zinc nitrate aqueous solution shows the milky color at the initial stage. Then during the heat treatment, the resm component of the coating solution is reacted with the inorganic component of the oxide layer of the steel sheet (the oxide layer having been formed before) to form a new composite material during the process of oxidation of the zinc ions at above the boiling point of zinc nitrate so as to form zinc oxide. This new composite material turns the color of the film to light green-yellow
The silicon additive is the polyester-transformed polyxyloxanic silicon. This lowers the surface tension of the coating solution, so that the moisture state of the steel sheet canbe improved.
A preferable example of this is the commodity model BYK-348 of BYK Chemie company of Germany.
In the present invention, the content of the silicon additive is limited to 4-13 g per 100 g of phosphoric acid within the solution. If the content is less than 4 g, then the addition effect does not appear, with the result that the moisture state of the steel sheet becomes insufficient . On the otherhand, if it exceeds 13 g, the aesthetics is aggravated.
The ethylene glycol acts to improve the external appearance by preventing the motley effect on the surface of the coiled steel sheet . To describe it m detail, after carrying out a continuous roll spreading operation, motley patterns appear very frequently on the surface of the coiled steel sheet This is due to the fact that when carrying out a heating at a relatively high temperature of 500 - 600°C, the material component having a boiling point of 100°C is evaporated earlier than the other volatile components of the coating material . Accordingly, if ethylene glycol which has a boiling point higher than that of water is added in the optimum amount, then the motley effect can be prevented even during a long time operation. Consequently, a uniform external appearance can be obtained.
In the present invention, the content of ethylene glycol is limited to 18-35 g per 100 g of phosphoric acid. If the content is less than 18 g, the aesthetic characteristics become insufficient, while if it exceeds 35 g, it does not completely evaporate even after the dryingbut partlyremains, with the result that the corrosion resistance and the water resistance are aggravated due to the hydroxyl group. The non-ionic surfactant is added for improving the continuous roll spreading workability, and a preferable example of this is the commodity model TRITON X-405 of Union Carbide company of the U.S.
To described it in detail, during the continuous roll spreading operation, the pressing between the rolls causes the temperature torise, andtherefore, thewatercomponent of the coating solution is evaporated. Accordingly, the phosphate and the resin components are dried fast to be transited from the liquid phase to the solidphase, with the result that a stickingproperty is generated, and it cannot be reversed to the water-soluble property. In order to prevent this phenomenon, the non-ionic surfactant is added. However, if its content is less than 3 g per 100 g of phosphoric acid, the properties of the coating solution is altered around the rolls so as to be led to have a sticking property and so as for the solidified solution to be adhered on the surface of the rolls in thick layers, to the degree that the operation becomes impossible. Onthe otherhand, if the content exceeds 11 g, then foams are severely producedwithinthe treating fluid, withthe result that the aesthetics of the coated film is aggravated.
Accordingly, in the present invention, the content of the non-ionic surfactant per 100 g of phosphoric acid is limited to 3-11 g. Conventionally, when spreading the coating solution on the non-oriented electrical steel sheet, if it is coated starting from the leading end of the weighty steel sheet coil, it becomes uneconomical. Therefore, first one kind of the coating solution is spread on a part of the coiled sheet, and then, the spreading operation is halted to coat the rest of the coiled sheet with another kind of the coating solution. Thus, the coating solution is left for several days without use, and thus if the coating solution is brought to be used thereafter, the coating solution might have lost the spreadability due to the fact that during the leaving of the several days , a gel reactionhas occurredbetween the inorganic chrome component and the resin component .
In contrast to this, if the resin-phosphate composite coating composition according to the present invention is used, the combination compatibility and the time stability become superior. Thus even when the coating solution of the present invention is used even after leaving it for one year, a superior spreading workability can be maintained. Accordingly, a treating solution saving effect and a waste solution minimizing effect can be obtained. Meanwhile, the present invention also provides a non-oriented electrical steel sheet on which the above described coating composition is coated.
Preferably, the coating composition is spread to a thickness of 0.7 - 2.8 μm on each face of the steel sheet. If the coated thickness is less than 0.7 μm, then the desired insulating strength cannot be obtained, while if it exceeds 2.8 μm, then a welding problem or the like may occur.
Next, the present invention also provides a method for forming an insulating film by coating the above described coating composition.
To describe it m more detail, m the present invention, water is added to the above described coating composition to form a coating solutionof the optimumconcentration. Under this condition, the present invention is not limited to a particular concentration of the coating solution.
The above described coating solution is spread on the surface of the non-oriented electrical steel sheet. Preferably, the dried coated thickness should be 0.7 ~ 2.8 μm, and this range ensures the insulating strength and the weldability.
The non-oriented electrical steel sheet thus coated is annealed at a temperature of 150 - 800°C for 14 - 45 seconds, thereby obtaining an insulating film of superior characteristics . This heat treatment temperature (the temperature of the heat treatment furnace) and the heat treatment time act as factors for deciding the film characteristics .
That is, m the present invention, the heat treatment temperature is limited to 150 - 800°C. If the temperature is below 150°C, the heat treatment becomes insufficient, with the result that the moisture remains, or that even if a coated film is formed, the productivity is aggravated. On the other hand, if the temperature exceeds 800°C, the control of the heat treatment temperature becomes difficult, with the result that not only non-uniform coating is done, but also an appearance defect is produced.
Meanwhile, in the present invention, the heat treatment time is limited to 14 - 45 seconds. If the heat treatment is carried out for less than 14 seconds at the highest allowable temperature of 800°C, the heat treatment becomes imperfect, with the result that the moisture remains . On the other hand, if the heat treatment is carriedout formore than45 seconds at theminimumallowable temperature of 150°C, then the coating material which has been chemically bonded with the oxide layer is oxidized, with the result that the color of the film is turned to black-brown to black, thereby generating color defects .
Most preferably, the heat treatment is carried out to a a temperature of 550 - 750°C for 18-37 seconds As described above, the present invention provides an organic-inorganic mixed coating composition in which the roll spreadability and the insulating film characteristics are superior.
Further, the present invention provides a non-oriented electrical steel sheet coated with the above coating composition, in which the aesthetics, the adherence, the corrosion resistance and the weldability are superior.
Now the present invention will be described in more details based on actual examples .
<Example 1>
Coating compositions for forming insulating films were prepared by varying the compositions as shown in Table 1 below for each 100 g of phosphoric acid of a primary aluminum phosphate solution
(DYP-30) , and then, this coating compositions were aged for 3 days. Then these coating compositions were spreadonnon-orientedelectrical steel sheets (0.5 mm thick, and containing 1.0% of Si) . Then these coatedsteel sheetsweremade toundergoaheat treatment at atemperature of 550°C for 30 seconds, and thus, non-oriented electrical steel sheets were obtained on which insulating films of a thickness of about 2.1 μm were coated respectively.
For these coated steel sheets, the characteristics of the coated insulating films were measured, and the measured results are showninTable 2 below. Underthis condition, the specificmeasuring methods were as follows.
Meanwhile, as shown inTable 2 below, the corrosionresistance was classified into: the case where the generation of rust was absent on the surface of the insulating film; the case where the generation of rust was present partly, and the case where the generation of rust was widely prevalent. These cases were indicated by 0, Δ and x respectively. Further, as to the peeling of the films, the case where the peeling was absent was indicated by 0, and the case where the peeling was present was indicated by x. Further, the case where the aesthetics was superior was indicated by 0, and the case where aesthetics was inferior was indicated by x. <Table 1>
Figure imgf000015_0001
* In the above table, CD indicates emulsion type acrylic-styrenic
resin (PA-P40) , indicates silicon additive (BYK-348) , ©indicates
non-ionic surfactant (TRITON X-405) , ® indicates ethylene glycol,
and (5) indicates zinc nitrate.
(1) Stress relieving heat treatment was carried out at 750°C for 2 hours under a 100% N gas atmosphere.
(2 ) The external appearances were evaluatedby collectively visually observing motley patterns, stripes, shining, and the color. As motley patterns and stripes were absent, and as a shining and a light green-yellow color were present, so much the quality of the coated film was thought to be superior. If the color of the coated film was non-chromatic or dark like the base sheet, if stripes were present and if the shining was too low so as to make the users evade the product, then the external appearance of the coated film was evaluated to be inferior.
(3) The insulating strength was evaluated by means of the electric current value (in amperes) when an input current (0.5
V and 1.0 A) was supplied under a pressure of 300 psi .
(4) The adherence (mmφ) was evaluated by the minimum arc diameter which did not show any peeling when the annealed steel sheets were surrounded around rods (10, 20, 30, ..., 100 mmφ) and the surrounded rods were bent by an angle of 180 degrees.
(5) The corrosion resistance was evaluated by visually observing the presence or absence of rust when the coated steel sheets were left indoor for one year and exposed outdoor for three months.
(6) The peeling of the coated film was evaluated by the presence or absence of peeling when an adhesive tape (poly propylene) was attached-detached on and from the annealed films .
As can be seen in Table 2 below, in the case of the inventive examples 1 and 2 (in which the conditions of the present invention were met) , not only the roll coating continuation workability but also the film characteristics such as the aesthetics, the insulating strength, the adherence, the corrosion resistance and the heat resistance (the property that the filmwas not peeled and the insulating strength was not lowered after the heat treatment) were superior. This owes to the fact that the resin and the inorganic additives were filled into between the phosphate crystals, thereby making the structure of the film dense.
In contrast to this, in the case of the comparative example 1 in which the addition of the emulsified acrylic-styrenic resin
(PA-P40) was insufficient, the aesthetics and the adherence were inferio . In the case of the comparative example 2 in which the resins additionwas excessive, theinsulatingstrengthandtheheatresistance were not satisfactory after the stress relieving heat treatment .
Meanwhile, in the cases of the comparative examples 3 and 4 in which the addition of the silicon additive departed from the range of the present invention, the aesthetics was not adequate.
<Table 2>
Figure imgf000017_0001
Further, in the case of the comparative example 5 in which theadditionof thenon-ionic surfactant (TRITONX-405) was insufficient, the continuous coatability was not adequate, to the degree that the film could not be formed. In the case of the comparative example 6 in which its addition was excessive, the aesthetics of the coated film was not desirable.
Further, in the case of the comparative example 7 in which the addition of ethylene glycol was excessive, the corrosion resistance and the aesthetics were not adequate . In the case of the comparative example 8 in which its addition was insufficient, the corrosion resistance was inferior, and the aesthetics was not desirable because motley patterns were appeared.
Further, in the case of the comparative example 9 in which the addition of zinc nitrate was insufficient, the aesthetics was inferior, while in the case of the comparative example 10 in which its addition was excessive, the heat resistance was not adequate by showing the film peeling and the like.
<Example 2> A film coating composition which was composed like that of the inventive example 1 of Example 1 was aged for 3 days. This coating composition was uniformly spread on non-oriented electrical steel sheets (0.5 mm thick, and containing 1.0% of Si by varying the coating thickness. Then the test pieces were annealed at 550°C for 30 seconds, and thus, the coated films were various as shown in Table 3 below. Then the non-oriented electrical steel sheets on which the coated films were different in the thickness were measured as to their film characteristics suchas insulating strength, corrosion measured by applying the TIG welding (welding current: 150 A, electrode: pure-W (3,2 mmφ), electrode gap: 0.35 mm, and the welding speed: 15 mm/sec) , and that the external appearance of the bead part after the welding and the generation of blow holes were visually observed.
In Table 3 below, in evaluating the corrosion resistance, the heat resistance and the weldability, if the evaluation value was superior, it was indicated by 0, while if the value was inferior, it was indicated by x. As can be seen in Table 3 below, in the case of the inventive examples 3 to 5 in which the film thicknesses were controlled to proper values, the film characteristics were superior, and particularly, the weldability was superior.
In contrast to this, in the case of the comparative example 11 in which the film thickness was too thin, the corrosion resistance and the insulating strength were not adequate. In the case of the comparative example 12 in which the film thickness was too thick, the weldability and the heat resistance were inferior.
<Table 3>
Figure imgf000019_0001
Figure imgf000020_0001
<Example 3>
A coating composition which was composed like that of the inventive example 2 of Example 1 was prepared, and it was aged for three days. This composition was coated on non-oriented electrical steel sheets (0.5 mm thick) uniformly and continuously. Then these test pieces were annealed at various heat treatment conditions as shown m Table 4 below, thereby manufacturing non-oriented electrical steel sheets .
As shown m Table 4 below, the case of the inventive example 6 which the heat treatment conditions were properly controlled, the insulating film was thick to the value of about 2.3 μm, and the film characteristics were superior.
<Table 4>
Figure imgf000020_0002
which was contacted to the oxide layer was oxidized to be turned to a black-brown to black color, thereby showing a severe appearance inadequacy.
Meanwhile, in the case of the comparative example 14 in which the heat treatment time was to short under the given heat treatment temperature, the formation of the film was insufficient due to the insufficient heat treatment.
According to the present invention as described above, the film characteristics such as aesthetics, insulating strength, heat resistance and the like are superior. Further, the contamination of the nature can be prevented, and the coated film are immune from property degradations after elapsing of time. Thus the organic-inorganic mixed coating composition of the present invention is useful to manufacturing the non-oriented electrical steel sheet.

Claims

WHAT IS CLAIMED IS:
1. A coating composition comprising for each 100 g of phosphoric acid of a primary aluminum phosphate solution:
28-98 g (solid weight) of an acid-soluble emulsion type acrylic-styrenic copolymer resin; 6-18 g of zinc nitrate; 4-13 g of a silicon additive; 18-35 g of ethylene glycol; and 3-11 g of non-ionic surfactant.
2. The coating composition as claimed in claim 1, wherein the acid-soluble emulsion type acrylic-styrenic copolymer resin has a pH value of 4 or less .
3. The coating composition as claimed in any one of claims land2, whereintheacid-solubleemulsiontypeacrylic-styrenic copolymer resin is composed of 35% of an acrylic compound and 65% of a styrenic compound.
4. A non-oriented electrical steel sheet comprising: a coating film formed by using a coating composition, the coating composition comprising for each 100 g of phosphoric acid of a primary aluminum phosphate solution:
28-98 g (solid weight) of an acid-soluble emulsion type acrylic-styrenic copolymer resin; 6-18 g of zinc nitrate; 4-13 g of a silicon additive; 18-35 g of ethylene glycol; and 3-11 g of non-ionic surfactant.
5. The non-oriented electrical steel sheet as claimed in claim 4, wherein the coating composition is coated to a thickness of 0.1 - 2.8 μm on each face of the steel sheet .
6. A method for coating an insulating film on a non-oriented electrical steel sheet, comprising the steps of: preparing a coating composition by adding for each 100 g of phosphoric acid of a primary aluminum phosphate solution: 28-98 g (solid weight) of an acid-soluble emulsion type acrylic-styrenic copolymer resin, 6-18 g of zinc nitrate, 4-13 g of a silicon additive,
18-35 g of ethylene glycol, and 3-11 g of non-ionic surfactant; spreading the coating composition on the non-oriented electrical steel sheet; and subjecting the electrical steel sheet (thus coated) to a heat treatment at a temperature of 150 - 800°C for 14-45 seconds.
7. The method as claimed in claim 6, wherein the coating composition is coated to a thickness of 0.7 ~ 2.8 μm on each face of the steel sheet .
PCT/KR2000/001414 2000-03-16 2000-12-07 Coating composition for forming insulating films, non-oriented electrical steel sheet with the coating composition coated thereon, and method for forming the insulating films on the steel sheet WO2001068778A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US09/980,942 US6667105B1 (en) 2000-03-16 2000-07-12 Coating composition for forming insulating films, non-oriented electrical steel sheet with the coating composition coated thereon, and method for forming the insulating films on the steel sheet
DE60012191T DE60012191D1 (en) 2000-03-16 2000-12-07 COATING COMPOSITION FOR FORMING INSULATING FILMS, COVERED NON-ORIENTED ELECTRIC STEEL SHEET, AND METHOD FOR FORMING INSULATING FILMS ON THE STEEL SHEET
EP00983516A EP1208166B1 (en) 2000-03-16 2000-12-07 Coating composition for forming insulating films, non-oriented electrical steel sheet with the coating composition coated thereon, and method for forming the insulating films on the steel sheet
JP2001567265A JP3546040B2 (en) 2000-03-16 2000-12-07 Coating composition for forming insulating film, non-oriented electrical steel sheet coated with the coating composition, and method of forming insulating film on the steel sheet

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR1020000013261A KR20010100204A (en) 2000-03-16 2000-03-16 A coating composition for insulation film and a method for manufacturing insulation film of non-grain oriented electric steel sheet by using it
KR2000/13261 2000-03-16

Publications (1)

Publication Number Publication Date
WO2001068778A1 true WO2001068778A1 (en) 2001-09-20

Family

ID=19655695

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2000/001414 WO2001068778A1 (en) 2000-03-16 2000-12-07 Coating composition for forming insulating films, non-oriented electrical steel sheet with the coating composition coated thereon, and method for forming the insulating films on the steel sheet

Country Status (8)

Country Link
US (1) US6667105B1 (en)
EP (1) EP1208166B1 (en)
JP (1) JP3546040B2 (en)
KR (1) KR20010100204A (en)
CN (1) CN1351637A (en)
DE (1) DE60012191D1 (en)
TW (1) TWI256965B (en)
WO (1) WO2001068778A1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101024748B (en) * 2006-02-23 2010-11-24 富思特制漆（北京）有限公司 Base paint for cultural-relic protection and preparing method therefor
WO2012041052A1 (en) * 2010-09-29 2012-04-05 宝山钢铁股份有限公司 Non-chromic insulating coating for non-oriented silicon steel
WO2012095835A1 (en) * 2011-01-12 2012-07-19 The Provost, Fellows, Foundation Scholars, And The Other Members Of Board, Of The College Of The Holy And Undivided Trinity Of Queen Elizabeth, Near Dublin A paint composition comprising zinc nitrate
EP2316980A4 (en) * 2008-07-22 2017-05-31 Nippon Steel & Sumitomo Metal Corporation Non-oriented electromagnetic steel plate and method for manufacturing the same
EP2366810A4 (en) * 2008-11-27 2017-08-23 Nippon Steel & Sumitomo Metal Corporation Electromagnetic steel sheet and method for producing same

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006042116A2 (en) * 2004-10-05 2006-04-20 Applied Thin Films, Inc. Aluminum phosphate compositions, coatings and related composites
JP4923291B2 (en) * 2005-12-02 2012-04-25 ソマール株式会社 Water-based moisture-proof insulation coating agent
CN101358096B (en) * 2008-09-05 2011-12-07 首钢总公司 Insulation environment friendly paint for non-oriented electrical steel
CN101358921B (en) * 2008-09-05 2011-04-20 首钢总公司 Method for detecting free phosphorus in electrical steel coatings
WO2010146821A1 (en) * 2009-06-17 2010-12-23 新日本製鐵株式会社 Electromagnetic steel sheet having insulating coating film and process for production thereof
CN101928490B (en) * 2009-06-24 2013-05-29 宝山钢铁股份有限公司 Chrome-free insulating paint and application thereof
PL2479315T3 (en) * 2009-09-15 2021-11-08 Nippon Steel Corporation Electrical steel sheet and method for manufacturing same
JP5923240B2 (en) * 2009-09-25 2016-05-24 ベック株式会社 Coating material
JP5423465B2 (en) * 2010-02-18 2014-02-19 新日鐵住金株式会社 Electrical steel sheet and method for producing electrical steel sheet
CN103045058B (en) * 2011-10-11 2015-06-03 攀钢集团攀枝花钢铁研究院有限公司 Insulation coating and electrical steel material, and preparation method thereof
JP5978009B2 (en) * 2012-05-30 2016-08-24 新日鐵住金株式会社 INSULATION COATING FORMING LIQUID AND METHOD FOR PRODUCING ELECTRIC STEEL STEEL WITH INSULATING COATING
CN105623346A (en) * 2014-11-05 2016-06-01 武陟县电业总公司 Transformer iron core insulating coating formula and application method thereof
CN110240832B (en) * 2019-03-07 2021-07-13 上海丰野表面处理剂有限公司 Chromium-free semi-organic insulating coating paint for non-oriented silicon steel

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5317648A (en) * 1976-08-02 1978-02-17 Nissan Chem Ind Ltd Process of coating inorganic paint
CN1106851A (en) * 1994-11-07 1995-08-16 刘小兵 Compound insulation and fire-proof paint
JPH0812919A (en) * 1994-06-28 1996-01-16 Mitsui Toatsu Chem Inc Resin composition for electrical sheet
EP0926249A1 (en) * 1997-12-19 1999-06-30 Armco Inc. Inorganic/organic insulating coating for non-oriented electrical steel

Family Cites Families (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0621267B2 (en) * 1985-10-28 1994-03-23 日新製鋼株式会社 Composition for forming electromagnetic steel sheet insulation film and method for forming electromagnetic steel sheet insulation film
JPH01116085A (en) * 1987-10-28 1989-05-09 Kawasaki Steel Corp Formation of insulating coat having superior suitability to blanking and welding on electrical steel sheet
JPH06104905B2 (en) * 1989-06-30 1994-12-21 住友金属工業株式会社 Method for forming electrical insulation film with excellent resistance to rust after stress relief annealing
JP2762147B2 (en) * 1990-02-15 1998-06-04 新日本製鐵株式会社 Method for producing non-oriented electrical steel sheet with excellent film properties after strain relief annealing and surface treating agent
JPH0578855A (en) * 1991-09-25 1993-03-30 Nisshin Steel Co Ltd Composition for forming magnetic steel sheet insulating film and method therefor
JPH0610149A (en) * 1992-06-25 1994-01-18 Sumitomo Metal Ind Ltd Insulating film for silicon steel sheet excellent in rusting resistance after stress relieving annealing
JP3117846B2 (en) 1993-07-26 2000-12-18 新日本製鐵株式会社 Non-oriented electrical steel sheet with excellent film properties and surface treatment agent for the steel sheet
JP2944849B2 (en) 1993-05-21 1999-09-06 新日本製鐵株式会社 Method for producing non-oriented electrical steel sheet with extremely good coating properties
JP2968427B2 (en) 1993-12-10 1999-10-25 新日本製鐵株式会社 Method for producing non-oriented electrical steel sheet having extremely excellent coating properties and surface treatment agent for the steel sheet
JP3205165B2 (en) * 1994-03-16 2001-09-04 新日本製鐵株式会社 Grain-oriented electrical steel sheet having a coating with excellent water resistance
JP3239312B2 (en) * 1994-03-31 2001-12-17 川崎製鉄株式会社 Electrical steel sheet with electrical insulation coating with excellent corrosion resistance
JPH1015484A (en) * 1996-06-28 1998-01-20 Kawasaki Steel Corp Silicon steel sheet having insulating coating film capable of stress relief annealing, excellent in corrosion resistance and containing no chromium compound, and formation of coating film thereof
JP3370235B2 (en) * 1996-07-30 2003-01-27 川崎製鉄株式会社 Method of forming an insulating coating excellent in corrosion resistance and free of chromium compound capable of strain relief annealing on the surface of an electrical steel sheet
JP3509475B2 (en) * 1997-06-26 2004-03-22 Ｊｆｅスチール株式会社 Non-oriented electrical steel sheet with insulating coating with excellent seizure resistance and slip resistance after strain relief annealing
JP3397291B2 (en) * 1997-09-01 2003-04-14 新日本製鐵株式会社 Non-oriented electrical steel sheet having insulating film with excellent film properties, method for producing the same, and insulating film forming agent used for the production
KR100321030B1 (en) * 1997-09-26 2002-03-08 이구택 Coating composition for insulation layer and method for forming insulation layer on non-oriented silicon steel sheets using the same
KR100321031B1 (en) * 1997-09-26 2002-03-08 이구택 Coating composition for insulation layer and method for forming insulation layer on non-oriented silicon steel sheets using the same
JP3408410B2 (en) * 1997-11-19 2003-05-19 新日本製鐵株式会社 Surface treatment agent for non-oriented electrical steel sheet and method of forming film using the same
WO1999063012A1 (en) * 1998-06-01 1999-12-09 Nihon Parkerizing Co., Ltd. Water-based surface-treating agent for metallic material
JP2000199070A (en) * 1998-12-28 2000-07-18 Kawasaki Steel Corp Treating agent of metal surface and corrosion-resistant metal plate

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5317648A (en) * 1976-08-02 1978-02-17 Nissan Chem Ind Ltd Process of coating inorganic paint
JPH0812919A (en) * 1994-06-28 1996-01-16 Mitsui Toatsu Chem Inc Resin composition for electrical sheet
CN1106851A (en) * 1994-11-07 1995-08-16 刘小兵 Compound insulation and fire-proof paint
EP0926249A1 (en) * 1997-12-19 1999-06-30 Armco Inc. Inorganic/organic insulating coating for non-oriented electrical steel

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Week 197813, Derwent World Patents Index; AN 1978-24444A, XP002907364 *
DATABASE WPI Week 197813, Derwent World Patents Index; AN 1996-112907, XP002907365 *
DATABASE WPI Week 199731, Derwent World Patents Index; AN 1997-333581, XP002907366 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101024748B (en) * 2006-02-23 2010-11-24 富思特制漆（北京）有限公司 Base paint for cultural-relic protection and preparing method therefor
EP2316980A4 (en) * 2008-07-22 2017-05-31 Nippon Steel & Sumitomo Metal Corporation Non-oriented electromagnetic steel plate and method for manufacturing the same
EP2366810A4 (en) * 2008-11-27 2017-08-23 Nippon Steel & Sumitomo Metal Corporation Electromagnetic steel sheet and method for producing same
US9984801B2 (en) 2008-11-27 2018-05-29 Nippon Steel & Sumitomo Metal Corporation Electrical steel sheet and manufacturing method thereof
US10665372B2 (en) 2008-11-27 2020-05-26 Nippon Steel Corporation Electrical steel sheet and manufacturing method thereof
WO2012041052A1 (en) * 2010-09-29 2012-04-05 宝山钢铁股份有限公司 Non-chromic insulating coating for non-oriented silicon steel
US9334405B2 (en) 2010-09-29 2016-05-10 Baoshan Iron & Steel Co., Ltd. Chromium-free insulation coating material for non-oriented silicon steel
WO2012095835A1 (en) * 2011-01-12 2012-07-19 The Provost, Fellows, Foundation Scholars, And The Other Members Of Board, Of The College Of The Holy And Undivided Trinity Of Queen Elizabeth, Near Dublin A paint composition comprising zinc nitrate

Also Published As

Publication number Publication date
KR20010100204A (en) 2001-11-14
EP1208166B1 (en) 2004-07-14
EP1208166A1 (en) 2002-05-29
TWI256965B (en) 2006-06-21
DE60012191D1 (en) 2004-08-19
US6667105B1 (en) 2003-12-23
JP3546040B2 (en) 2004-07-21
CN1351637A (en) 2002-05-29
JP2003526727A (en) 2003-09-09

Similar Documents

Publication Publication Date Title
EP1208166B1 (en) Coating composition for forming insulating films, non-oriented electrical steel sheet with the coating composition coated thereon, and method for forming the insulating films on the steel sheet
EP2046899B1 (en) Coating solution for forming insulating film with excellent corrosion resistance property and film close adhesion property and film intensity without chrome and a method for making the insulation film on non-oriented electrical steel sheet by using it
KR100966819B1 (en) Cr -free coating solution, manufacturing method and steel sheet, manufacturing method
JPH11241173A (en) Inorganic/organic insulating coating film for non-oriented silicon steel
US4288492A (en) Insulating coating compositions applied on electrical steel sheets
KR100415679B1 (en) A manufacturing method of organic resin coated steel sheets for automotive fuel tank body with good press process property and sheets manufactured from it
JP2001220683A (en) Silicon steel sheet coated with insulated film
EP0277243B1 (en) Process for forming insulating film on electrical sheet
JP4532690B2 (en) Metal material with resin-based corrosion-resistant layer
US5482787A (en) Organic composite coated steel strip having improved corrosion resistance and spot weldability
JPS61183475A (en) Improved dip plating method
JP2003193252A (en) Method of producing silicon steel sheet with insulating film having excellent film appearance
KR100411279B1 (en) A coating solution for making insulation film on non-oriented electrical steel sheet and a method for making the insulation film on non-oriented electrical steel sheet by using it
KR100321031B1 (en) Coating composition for insulation layer and method for forming insulation layer on non-oriented silicon steel sheets using the same
JPH04308093A (en) Silicon steel sheet having electrolytic-treated insulating film and its production
KR101507941B1 (en) Composition of oriented electrical steel sheet for forming insulation film, method for forming insulating film using the same, and oriented electrical steel sheet manufactured by the method
JP2008230117A (en) Resin coating tin plated steel sheet, can, and can lid
JPH05247663A (en) Steel material subjected to rust stabilization treatment and its treating method
JPS61177378A (en) Chromated cr-containing steel sheet having superior suitability to coating with paint
KR0125318B1 (en) MANUFACTURING METHOD FOR PYRO-BLACK Zn-Cu ALLOY COATED STEEL SHEET
JP2004083920A (en) Steel strip having excellent reddening resistance during high temperature oxidation and method for manufacturing the same
CN112639165A (en) Electromagnetic steel sheet with insulating coating and method for producing same
WO2004090196A1 (en) Surface-treated, zinc-plated steel sheet having excellent resistance to tape peeling, method for producing same, and surface treatment agent
JPH04358079A (en) Electric steel sheet with electric insulating coating film having satisfactory additional coatability
KR19980038067A (en) Coating composition for forming non-oriented electrical steel sheet insulation coating with excellent appearance and corrosion resistance

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 00807715.0

Country of ref document: CN

AK Designated states

Kind code of ref document: A1

Designated state(s): CN JP US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR

121 Ep: the epo has been informed by wipo that ep was designated in this application
ENP Entry into the national phase

Ref document number: 2001 567265

Country of ref document: JP

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 09980942

Country of ref document: US

WWE Wipo information: entry into national phase

Ref document number: 2000983516

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 2000983516

Country of ref document: EP

WWG Wipo information: grant in national office

Ref document number: 2000983516

Country of ref document: EP