Electrical steel sheet and method for manufacturing same
An embodiment of the present invention provides an electrical steel sheet including: an upper adhesive layer positioned on an upper surface of an electrical steel sheet; and an lower adhesive layer positioned on a lower surface of the electrical steel sheet, wherein the upper adhesive layer has a pencil hardness of F or lower, and the lower adhesive layer has a pencil hardness of H or higher.
1. An electrical steel sheet comprising:
an upper adhesive layer positioned on an upper surface of an electrical steel sheet; and
a lower adhesive layer positioned on a lower surface of the electrical steel sheet,
wherein the upper adhesive layer has a pencil hardness of F or lower, and
the lower adhesive layer has a pencil hardness of H or higher.
2. The electrical steel sheet of claim 1 , wherein
the upper adhesive layer includes a resin having a weight average molecular weight of 15,000 to 50,000, and
the lower adhesive layer includes a resin having a weight average molecular weight of 1000 to 10,000.
3. The electrical steel sheet of claim 1 , wherein
the upper adhesive layer further includes a hardener of 3 wt % or less, and
the lower adhesive layer further includes a hardener of 5 to 10 wt %.
4. The electrical steel sheet of claim 1 , wherein
the upper adhesive layer includes a resin having a hydroxyl group equivalent of 1 to 10 mgKOH/g, and
the lower adhesive layer includes a resin having a hydroxyl group equivalent of 15 to 20 mgKOH/g.
5. The electrical steel sheet of claim 1 , wherein
each of the resins included in the upper adhesive layer and the lower adhesive layer includes one or more of an epoxy-based resin, a siloxane-based resin, an acryl-based resin, a phenolic resin, a styrene-based resin, a vinyl-based resin, an ethylene-based resin, an ester-based resin, and a urethane-based resin.
6. The electrical steel sheet of claim 3 , wherein
each of the hardeners included in the upper adhesive layer and the lower adhesive layer includes one or more of a melamine-based hardener, a urethane-based hardener, an aliphatic polyamine hardener, a modified aliphatic polyamine hardener, an aromatic polyamine hardener, and an organic acid anhydride hardener.
7. A manufacturing method of an electrical steel sheet, comprising:
applying an upper adhesive composition to an upper surface of an electrical steel sheet to form an upper adhesive layer; and
applying a lower adhesive composition to a lower surface of the electrical steel sheet to form a lower adhesive layer,
wherein the upper adhesive composition includes a resin having a hydroxyl group equivalent of 1 to 10 mgKOH/g, and
the lower adhesive composition includes a resin having a hydroxyl group equivalent of 15 to 20 mgKOH/g.
8. The manufacturing method of the electrical steel sheet of claim 7 , wherein
the upper adhesive composition includes a resin having a weight average molecular weight of 15,000 to 50,000, and
the lower adhesive composition includes a resin having a weight average molecular weight of 1000 to 10,000.
9. The manufacturing method of the electrical steel sheet of claim 7 , wherein
the upper adhesive composition further includes 3 wt % or less of a hardener with respect to 100 wt % of a solid content, and
the lower adhesive composition further includes 5 to 10 wt % of a hardener with respect to 100 wt % of a solid content.
10. An electrical steel sheet laminate in which a plurality of electrical steel sheets are stacked, and an upper adhesive layer and a lower adhesive layer are interposed in an order between the electrical steel sheets,
wherein the upper adhesive layer has a pencil hardness of F or lower, and
the lower adhesive layer has a pencil hardness of H or higher.
11. The electrical steel sheet of claim 10 , wherein
the upper adhesive layer includes a resin having a weight average molecular weight of 15,000 to 50,000, and
the lower adhesive layer includes a resin having a weight average molecular weight of 1000 to 10,000.
12. The electrical steel sheet of claim 10 , wherein
the upper adhesive layer further includes a hardener of 3 wt % or less, and
the lower adhesive layer further includes a hardener of 5 to 10 wt %.
13. The electrical steel sheet of claim 10 , wherein
the upper adhesive layer includes a resin having a hydroxyl group equivalent of 1 to 10 mgKOH/g, and
the lower adhesive layer includes a resin having a hydroxyl group equivalent of 15 to 20 mgKOH/g.