Method for producing lacquer-coated electrical strips, and lacquer-coated electrical strip

Patent metadata

Field	Value
Publication number	US-11998946-B2
Application number	US-201917251662-A
Country	US
Kind code	B2
Filing date	Jun 14, 2019
Priority date	Jun 14, 2018
Publication date	Jun 4, 2024
Grant date	Jun 4, 2024

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.

First claim

The invention claimed is:

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.

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.

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

4. 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.

5. 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.

6. 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.

7. 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.

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

9. 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.

10. 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.

11. 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.

Assignees

• Voestalpine Stahl Gmbh

Inventors

• Strauss Bernhard
• Fluch Ronald
• Tiefenthaller Roman

Classifications

• B05D1/28 Primary

  performed by transfer from the surfaces of elements carrying the liquid or other fluent material, e.g. brushes, pads, rollers · CPC title

• B05D3/102

  Pretreatment of metallic substrates (C23C takes precedence) · CPC title

• B05D7/14

  to metal, e.g. car bodies (involving a chemical reaction between the metal and the coating C23) · CPC title

• C09D129/04

  Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids · CPC title

• H01B13/065 Primary

  Insulating conductors with lacquers or enamels · CPC title