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
• • 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
  • C09D129/00—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 alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Coating compositions based on hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Coating compositions based on derivatives of such polymers
  • C09D129/02—Homopolymers or copolymers of unsaturated alcohols
  • C09D129/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
• • 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
  • C09D133/00—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 only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
  • C09D133/04—Homopolymers or copolymers of esters
  • C09D133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
  • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
  • H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
  • H01B3/44—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L25/00—Compositions of, 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; Compositions of derivatives of such polymers
  • C08L25/02—Homopolymers or copolymers of hydrocarbons
  • C08L25/04—Homopolymers or copolymers of styrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L25/00—Compositions of, 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; Compositions of derivatives of such polymers
  • C08L25/02—Homopolymers or copolymers of hydrocarbons
  • C08L25/04—Homopolymers or copolymers of styrene
  • C08L25/08—Copolymers of styrene
  • C08L25/14—Copolymers of styrene with unsaturated esters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L29/00—Compositions of 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 alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
  • C08L29/02—Homopolymers or copolymers of unsaturated alcohols
  • C08L29/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/04—Homopolymers or copolymers of esters
  • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical

Definitions

• the iron core should be made of the electrical steel sheet having the good punchability since the core is manufactured by punching.
• the punchability of the electrical steel sheet may be affected by a lot of factors, one of which is the lubricating property of the surface of the electrical steel sheet. In connection with this, it is known that the punchability can be enhanced if the surface is coated with an organic substance.
• the transformer, generator, motor, etc. in which the iron core is used will generate heat during the operation, whereby the temperature will be sometimes elevated up to about 150C. If, in this case, the organic coating has no heat resistivity, there is a danger of carbonization of the coated film and difficulty in operation of those apparatus.
• This invention relates to a composition adapted for use in the electrical steel sheet which fomis an organic coating having good punchability, high electric insulation property, heat resistance and good adhesiveness.
• an organic coating composition adapted for use in the electrical steel sheet which comprises, as the main components, 10 parts by weight of the polyvinyl alcohol, 0.5 to 5 parts by weight, as the solid value, of the styrenetype emulsion resin and 2 to 10 parts by weight, as the solid value, of the water-soluble acrylic resin, said styrene-type emulsion resin containing at least 50% by weight of styrene.
• an electrical steel sheet having the above composition applied thereto is also provided.
• composition for forming the organic coating according to this invention is intended for coating the electrical steel sheet which is made of the silicon steel or the carbon steel.
• the percentage" or the part” used herein is based on the weight.
• This composition may be composed of a suspension of 0.5 to 5 parts, as the solid value, of the styrene-type emulsion resin containing at least 50% of styrene and 2 to 10 parts, as the solid value, of the water-soluble acrylic resin mixed in 10 parts of the polyvinyl alcohol, as the main components.
• the polyvinyl alcohol used in this invention is one having the average polymerization degree between 500 and 2000 and the saponification degree between and 99 mol which may be partial saponification or complete saponification. If this polyvinyl alcohol only is dissolved in hot or cold water and applied to the electrical steel sheet, a uniform coating may be obtained. However, this coating is itself hygroscopic, poor waterproof property and thus can not be used practically. Moreover, it has poor heat resistivity. Accordingly, if the electrical steel sheet is subjected to the heat treatment at 200C X 48 hours, the coating is decreased in amount remarkably, turns its color and becomes brittle. Hereinafter it is referred to as having heatresistanee that the coating is not decreased so much in amount and does not change its color when subjected to the heat treatment.
• the styrene-type emulsion resin used in this invention is the styrene emulsion resin, the styrene'acrylate emulsion resin, or the styrene-vinyl acetate emulsion resin, etc., which may be made from the styrene itself or from the copolymerization product of the styrene with the other monomer. In case of the copolymerization, the styrene should be contained in an amount of 50% or more.
• the heat resistant property of the coating is so poor that when the styrene-type resin having not more than 50% styrene is singly applied to the electrical steel sheet, the loss of coating occurs after the heat treatment at 200C for 48 hours. Even when said resin is used in admixture with the polyvinyl alcohol and the water-soluble acrylic resin, the heat resistance of the coating is neverenhanced. However, in case of the styrene emulsion resin having at least 50% styrene, the heat resistance of the coating is remarkably improved.
• the film can not be formed very well or the film can not be fomied uniformly.
• the adhesiveness of the coating is also poor.
• the coating becomes softened during the applying or curing work, whereby the coating may be injured by rubbing with the hearth roll supporting the steel strip in the furnace.
• its oil-proofness against the transformer oil, machine oil, etc. and its anti-solvent property against such organic solvent as acetone, xylene,-trichlene are also so poor that the coating may easily be dissolved or swollen thereby.
• the water-soluble acrylic resin used in this invention may be the methyl acrylate resin, the ethyl acrylate resin, the butyl acrylate resin; the methyl methacrylate resin, the ethyl methacrylate resin, the butyl methacryl- 7 ate resin, or their copolymerized product.
• the acrylic resin which can be made water-soluble by dissolving into such alcohols as isopropyl alcohol, etc. having mutual solubility with water, even if it is not directly dissolved in water.
• this water-soluble acrylic resin is singly coated and cured on the electrical steel sheet, the coating formed has poor heat resistivity as is the case with the polyvinyl alcohol, and poor adhesiveness.
• the styrene-type emulsion resin and the watersoluble acrylic resin is singly applied to the electrical property of the polyvinyl alcohol can not be improved, while the styrene-type emulsion resin becomes too softened during curing to prohibit the occurring of scars thereon.
• the adhesiveness is insuificient and the heat resistivity is greatly deteriorated.
• the main components of the organic coating composition for the electrical steel sheet according to this invention are the polyvinyl alcohol, the styrene-type emulsion resin, and the water-soluble acrylic resin.
• a pigment or a resin equivalent to the pigment may be added.
• the amount of these substance to be added may vary with the degree of coloration desired, but the amount ranging between 0.2 and 2 parts based upon 10 parts of the polyvinyl alcohol is desirable.
• the resin equivalent orv corresponding to the pigment may be, for example, a sulfate of lignin for giving a brown color tone to the coating.
• the coating composition there are various defects occurring in the practical operation.
• the inventors have found that when the polyvinyl alcohol, the styrene-type emulsion resin and the water-soluble acrylic resin are mixed at the ratio of 0.5 to 5 parts (as solid value) of the styrene-type emulsion resin and 2 to 10 parts (as solid value) of the water-soluble acrylic resin based on 10 parts of the polyvinyl alcohol to form a coating composition and the composition is coated on the electrical steel sheet, it shows the excellent coating properties required for the electrical steel sheet such as punchability, electric insulation property, high adhesiveness, heat resistivity, oil-proof and solvent-proof property, and so on. It is also found that a uniform coating having bright appearance can be formed by the high-temperature, short-time baking as distinguished from the low-temperature, long-time drying of the organic varnish.
• the styrene-type resin should be included in an amount of 0.5 to S'parts. If it is below 0.5 parts, the heat resistivity can not be improved appreciably. If it is more than 5 parts, the film-forming property is poor; the appearance has no brightness and the oiland solvent-proof property against the transformer oil and the organic solvent such as acetone, methanol, xylol is insufficient.
• the water-soluble acrylic resin if it is below 2 parts, the corrosion-resistance and water-proof The conditions of curing the coating may be 40 seconds at the steel sheet temperature of 380C, or 15 seconds at 600C, which demonstrates that the hightemperature, short-time curing makes it possible to obtain a uniform coating.
• Example I Polyvinyl alcohol (average polymerization degree 1000; saponification degree 88 mol 1 l0 parts Styreneacrylate emulsion (weight ratio:
• the bright and uniform coatings were obtained.
• the properties such as the weight of coating, the inter-layer electric insulation resistance, the adhe- (Reference Example 2) of 40% (solid value) polystyrene, an aqueous solution (Reference Example 3) of 40% (solid value) acrylic resin were singly coated on the respective electrical steel sheets in an amount of 4 siveness, the corrosion resistance and water-proof 5 t0 6 g/m which were then Subjected to the heat treatproperty, the heat-resistivity, the oiland solvent-proof at for 30 Seconds-
• the Properties of the property, the punchability, etc. are indicated in Table Coatmgs obtalfled werefivaluated as Examples 1 t0 1 3.
• the decreased amount (/1) of the weight of the film is the decreased amount (/1) of the weight of the film.
• the films obtained in the above Examples of this invention were all excellent in the inter-layer resistance, adhesiveness, heat-resistivity, corrosion-resistance and waterproof property, oil-proof property and solventproof property, and so on.
• An organic coating composition adapted for use in the electrical steel sheet which comprises, as the main components, (A) 10 parts by weight of polyvinyl alcohol,'(B) 0.5 to parts by weight, as the solid value, of styrene resin selected from the group consisting of styrene homopolymer and copolymers of styrene with vinyl acetate or alkyl acrylate and (C) 2 to parts by weight, as the solid value, of a watersoluble acrylic resin consisting essentially of at least one monomer selected from the group consisting of alkyl acrylate and alkyl methacrylate, said styrene resin containing at least 50% by weight of styrene.-
• An organic coating composition according to claim 1 which additionally contains a pigment.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Materials Engineering (AREA)
• Power Engineering (AREA)
• Dispersion Chemistry (AREA)
• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Paints Or Removers (AREA)
• Organic Insulating Materials (AREA)
• Laminated Bodies (AREA)

Applications Claiming Priority (1)

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Cited By (6)

Citations (3)

• 1973
  • 1973-02-12 JP JP1726873A patent/JPS5315533B2/ja not_active Expired
• 1974
  • 1974-02-05 US US00439951A patent/US3853971A/en not_active Expired - Lifetime

Patent Citations (3)

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