Underlayer formulation for tape media

Patent metadata

Field	Value
Publication number	US-11158340-B2
Application number	US-201916546161-A
Country	US
Kind code	B2
Filing date	Aug 20, 2019
Priority date	Aug 20, 2019
Publication date	Oct 26, 2021
Grant date	Oct 26, 2021

Abstract

In one general approach, a product includes an underlayer of a magnetic recording medium. The underlayer has encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an aromatic polymer, and a polymeric binder binding the encapsulated nanoparticles. A magnetic recording layer is formed above the underlayer. In another general approach, a product includes an electrically conductive underlayer of a magnetic recording medium. The underlayer has encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an aromatic polymer, and a polymeric binder binding the encapsulated nanoparticles. A magnetic recording layer is formed above the underlayer. The magnetic nanoparticles have an average magnetic field strength of less than 200 Oersted (Oe). An average concentration of the encapsulated nanoparticles in the underlayer is at least 35 vol %.

First claim

What is claimed is:

1. A product, comprising:
an underlayer of a magnetic recording medium, the underlayer having:
encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an aromatic polymer, and
a polymeric binder binding the encapsulated nanoparticles; and

a magnetic recording layer formed above the underlayer.

2. The product as recited in claim 1 , wherein the magnetic nanoparticles have an average magnetic field strength of less than 200 Oersted (Oe).

3. The product as recited in claim 1 , wherein an average concentration of the encapsulated nanoparticles in the underlayer is at least 35 vol %.

4. The product as recited in claim 1 , wherein the underlayer is characterized as having an onset glass transition temperature of at least 35° centigrade in a tensile storage modulus (E′) vs. temperature plot.

5. The product as recited in claim 1 , wherein the underlayer is electrically conductive for assisting in dissipating a charge in the product, wherein the aromatic polymer includes a carbamate, wherein an average concentration of the encapsulated nanoparticles in the underlayer is at least 35 vol %, wherein no wear particles are present in the product.

6. The product as recited in claim 1 , wherein the magnetic nanoparticles include chromium oxide.

7. The product as recited in claim 1 , wherein an average diameter of the magnetic nanoparticles is in a range of 2 nanometers to 15 nanometers.

8. The product as recited in claim 1 , wherein the aromatic polymer includes a carbamate.

9. A product, comprising:
an underlayer of a magnetic recording medium, the underlayer having:
encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an aromatic polymer, and
a polymeric binder binding the encapsulated nanoparticles; and

a magnetic recording layer formed above the underlayer,
wherein the aromatic polymer includes methylene bis diphenyl carbamate.

10. The product as recited in claim 1 , wherein an average thickness of the aromatic polymer is in a range of 1 nanometer to 8 nanometers.

11. The product as recited in claim 1 , wherein the polymeric binder includes an acrylic polymer.

12. The product as recited in claim 1 , wherein an average thickness of the underlayer is less than 1 micron.

13. The product as recited in claim 1 , wherein no wear particles are present in the underlayer.

14. The product as recited in claim 1 , wherein no wear particles are present in the product.

15. The product as recited in claim 1 , wherein the recording layer is substantially not physically intermixed with the underlayer in the product such that an upper surface of the underlayer is substantially flat, with a modulation of less than about 25% of a thickness of an interfacial boundary between the underlayer and the recording layer.

16. The product as recited in claim 1 , wherein the magnetic recording medium is a magnetic recording tape.

17. A product, comprising:
an electrically conductive underlayer of a magnetic recording medium, the underlayer having:
encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an aromatic polymer, and
a polymeric binder binding the encapsulated nanoparticles; and

a magnetic recording layer formed above the underlayer,
wherein the magnetic nanoparticles have an average magnetic field strength of less than 200 Oersted (Oe),
wherein an average concentration of the encapsulated nanoparticles in the underlayer is at least 35 vol %.

18. The product as recited in claim 17 , wherein the underlayer is characterized as having an onset glass transition temperature of at least 35° centigrade in a tensile storage modulus (E′) vs. temperature plot.

19. The product as recited in claim 17 , wherein the magnetic nanoparticles include chromium oxide.

20. The product as recited in claim 17 , wherein an average diameter of the magnetic nanoparticles is in a range of 2 nanometers to 15 nanometers.

21. The product as recited in claim 17 , wherein the aromatic polymer includes a carbamate.

22. The product as recited in claim 17 , wherein an average thickness of the aromatic polymer is in a range of 1 nanometer to 8 nanometers.

23. The product as recited in claim 17 , wherein the polymeric binder includes an acrylic polymer.

24. The product as recited in claim 17 , wherein no wear particles are present in the product.

25. The product as recited in claim 17 , wherein the aromatic polymer includes methylene bis diphenyl carbamate.

Assignees

• IBM

Inventors

• Bradshaw Richard

Classifications

• G11B5/716

  characterised by two or more magnetic layers · CPC title

• G11B5/714

  characterised by the dimension of the magnetic particles · CPC title

• G11B5/712 Primary

  characterised by the surface treatment or coating of magnetic particles · CPC title

• G11B5/71

  characterised by the lubricant · CPC title

• G11B5/78

  Tape carriers · CPC title