# US 11,998,946 B2 · Method for producing lacquer-coated electrical strips, and lacquer-coated electrical strip

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- Number: US 11,998,946 B2
- Document ID: US11998946B2
- Status: Granted
- Kind: B2
- Application number: 17/251,662
- Filed: 2019-06-14
- Published: 2021-06-03
- Granted: 2024-06-04
- Earliest claimed: 2018-06-14
- Assignees: voestalpine Stahl GmbH
- Applicants: voestalpine Stahl GmbH
- Inventors: Bernhard Strauss; Ronald Fluch; Roman Tiefenthaller
- Web page: https://patentgrep.com/patent/US11998946B2

## CPC

- B05D 1/28: performed by transfer from the surfaces of elements carrying the liquid or other fluent material, e.g. brushes, pads, rollers
- B05D 3/102: {Pretreatment of metallic substrates (C23C takes precedence)}
- B05D 5/12: to obtain a coating with specific electrical properties
- B05D 7/14: to metal, e.g. car bodies (involving a chemical reaction between the metal and the coating C23)
- C09D 129/04: Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
- H01B 13/065: {Insulating conductors with lacquers or enamels}
- H01F 41/00: Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- B05D 2202/10: based on Fe
- B05D 2252/02: of indefinite length
- B05D 2252/10: Applying the material on both sides
- B05D 2350/10: Phosphatation
- B05D 2350/60: Adding a layer before coating
- C08K 3/32: Phosphorus-containing compounds
- C08K 2003/329: {Phosphorus containing acids}
- B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02)
- 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 (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

A process for producing a coated electrical steel strip includes application of a pretreatment layer over a first flat side of a rolled electrical steel strip. The layer thickness of the pretreatment layer is in the range from 10 nm to 100 nm, in particular from 20 nm to 50 nm. The rolled electrical steel strip which has been coated with the pretreatment layer is then coated with an insulating lacquer layer over the pretreatment layer. The insulating lacquer layer is applied by roll application using a roll and no deliberate drying and/or crosslinking of the pretreatment layer is carried out after application of the pretreatment layer and before coating with the insulating lacquer layer.

## Claims

### Claim 1

A process for producing a coated electrical steel strip, comprising:
application of a pretreatment layer over a first flat side of a rolled electrical steel strip, where a layer thickness of the pretreatment layer is in a range from 10 nm to 100 nm; and
after application of the pretreatment layer, coating of the rolled electrical steel strip with an insulating lacquer layer over the pretreatment layer, the insulating lacquer layer being applied by roll application using a roll, and without deliberate drying and/or crosslinking of the pretreatment layer being carried out after application of the pretreatment layer and before coating with the insulating lacquer layer, wherein the pretreatment layer consists
from 1.0% by weight to 5.0% by weight or 1.5% by weight to 3.0% by weight, of polyvinyl alcohol,
from 0.01% by weight to 0.5% by weight, or from 0.05% by weight to 0.3% by weight, of phosphoric acid, and
a remaining balance of an organic or inorganic solvent and/or water.

### Claim 2

A process for producing a coated electrical steel strip, comprising:
application of a pretreatment layer over a first flat side of a rolled electrical steel strip, where a layer thickness of the pretreatment layer is in a range from 10 nm to 100 nm; and
after application of the pretreatment layer, coating of the rolled electrical steel strip with an insulating lacquer layer over the pretreatment layer, the insulating lacquer layer being applied by roll application using a roll, and without deliberate drying and/or crosslinking of the pretreatment layer being carried out after application of the pretreatment layer and before coating with the insulating lacquer layer,
wherein the insulating lacquer layer is a baking lacquer layer which includes an epoxy resin or an epoxy resin mixture and at least one latent hardener configured to convert a thermoplastic into a thermoset, wherein the pretreatment layer consists
from 1.0% by weight to 5.0% by weight or 1.5% by weight to 3.0% by weight, of polyvinyl alcohol,
from 0.01% by weight to 0.5% by weight, or from 0.05% by weight to 0.3% by weight, of phosphoric acid, and
a remaining balance of an organic or inorganic solvent and/or water.

### Claim 3 (depends on 2)

The process according to claim 2, wherein the layer thickness of the pretreatment layer is in the range from 20 nm to 50 nm.

### Claim 4 (depends on 2)

The process according to claim 2, wherein the pretreatment layer is applied by roll application using another roll located upstream of the roll used for applying the insulating lacquer layer by roll application, with respect to a strip path along which the rolled electrical steel strip is fed.

### Claim 5 (depends on 2)

The process according to claim 2, further comprising, before application of the pretreatment layer, cleaning of the rolled electrical steel strip by washing and/or brushing.

### Claim 6 (depends on 2)

The process according to claim 2, wherein the pretreatment layer consists
from 1.5% by weight to 3.0% by weight, of polyvinyl alcohol,
from 0.05% by weight to 0.3% by weight, of phosphoric acid, and
the remaining balance of the organic or inorganic solvent and/or water.

### Claim 7 (depends on 2)

The process according to claim 2, wherein the pretreatment layer is applied directly to the first flat side of the rolled electrical steel strip, consisting of a steel surface of the rolled electrical steel strip.

### Claim 8 (depends on 2)

The process according to claim 2, wherein the insulating lacquer layer is applied directly to a surface of the pretreatment layer.

### Claim 9 (depends on 2)

The process according to claim 2, wherein a layer thickness of the insulating lacquer layer is in a range from 1 μm to 12 μm.

### Claim 10 (depends on 2)

The process according to claim 2, wherein a layer thickness of the insulating lacquer layer is equal to or less than 6 μm, 4 μm, 2 μm or 1 μm.

### Claim 11 (depends on 2)

The process according to claim 2, further comprising:
application of a further pretreatment layer over a second flat side of the rolled electrical steel strip; and
after application of the further pretreatment layer, coating of the rolled electrical steel strip with a further insulating lacquer layer over the further pretreatment layer.