Process for forming tape media having synergistic magnetic recording layer and underlayer

Patent metadata

Field	Value
Publication number	US-12014760-B2
Application number	US-201916546057-A
Country	US
Kind code	B2
Filing date	Aug 20, 2019
Priority date	Aug 20, 2019
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

A method, according to one approach, includes forming an underlayer of a magnetic recording medium. The underlayer includes first encapsulated nanoparticles each comprising a first magnetic nanoparticle encapsulated by a first aromatic polymer, and a first polymeric binder binding the first encapsulated nanoparticles. A magnetic recording layer is formed above the underlayer. The magnetic recording layer includes second encapsulated nanoparticles each comprising a second magnetic nanoparticle encapsulated by an encapsulating layer, and a second polymeric binder binding the second encapsulated nanoparticles.

First claim

What is claimed is:

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

forming a magnetic recording layer above the underlayer, the magnetic recording layer comprising:
second encapsulated nanoparticles each comprising a second magnetic nanoparticle encapsulated by an encapsulating layer, and
a second polymeric binder binding the second encapsulated nanoparticles,

wherein forming the underlayer includes mixing the first encapsulated magnetic nanoparticles with the first polymeric binder for forming a mixture, and spray coating the mixture onto a structure.

2. The method as recited in claim 1 , wherein forming the underlayer includes mixing the first polymeric binder with the first encapsulated nanoparticles and a solvent to form the mixture; the spray coating for applying the mixture onto the structure; at least partially drying the applied mixture; and radiating the at least partially dried applied mixture for causing crosslinking of the first polymeric binder.

3. The method as recited in claim 2 , wherein the first polymeric binder collapses onto the first encapsulated nanoparticles as the solvent is removed during the drying.

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

5. The method as recited in claim 1 , wherein an average concentration of the first encapsulated nanoparticles in the underlayer is greater than 35 vol %.

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

7. The method as recited in claim 1 , wherein the underlayer is characterized as having an absolute value of a tensile storage modulus (E′) thereof greater than 6 GPa.

8. The method as recited in claim 1 , wherein the underlayer is electrically conductive.

9. The method as recited in claim 1 , wherein the first magnetic nanoparticles include chromium oxide.

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

11. The method as recited in claim 1 , wherein the first aromatic polymer includes a carbamate.

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

13. The method as recited in claim 1 , wherein the first polymeric binder includes an acrylic polymer.

14. The method as recited in claim 1 , wherein the magnetic recording layer is substantially not intermixed with the underlayer.

15. The method as recited in claim 1 , wherein forming the recording layer includes heating the second magnetic nanoparticles and a second aromatic polymer to a temperature of at least 200 degrees Celsius; mixing the second polymeric binder with the heated second magnetic nanoparticles, the second aromatic polymer, and a solvent to form a mixture; applying the mixture onto the underlayer; at least partially drying the applied mixture; and radiating the at least partially dried applied mixture for causing crosslinking of the second polymeric binder.

16. The method as recited in claim 15 , wherein the mixture further includes an acrylic terminated polyester.

17. The method as recited in claim 1 , wherein forming the recording layer includes radiating a mixture comprising the second magnetic nanoparticles and a second aromatic polymer for causing the second aromatic polymer to crosslink, thereby forming the encapsulating layer around the second magnetic nanoparticles.

18. The method as recited in claim 1 , wherein the second magnetic nanoparticles include at least one magnetic material selected from the group consisting of: nickel, cobalt, and iron.

19. The method as recited in claim 1 , wherein the second magnetic nanoparticles include at least one magnetic material selected from the group consisting of: Co 3 O 4 , CoFe, Fe 3 O 4 , Fe 2 O 3 , and Co(fcc).

20. The method as recited in claim 1 , wherein an average diameter of the second magnetic nanoparticles is in a range of 2 nanometers to 20 nanometers.

21. The method as recited in claim 1 , wherein the encapsulating layer is a layer selected from the group consisting of: a polyaromatic film, and a graphite-like dominated continuous film.

22. The method as recited in claim 1 , wherein an average thickness of each encapsulating layer is less than 1 nanometer.

23. The method as recited in claim 1 , comprising adding lubricant molecules during formation of the recording layer, the lubricant molecules being coupled to a surface of the recording layer upon formation of the recording layer, wherein an amount of the lubricant molecules along the surface of the recording layer is less than an amount to form a continuous lubricant film along the surface of the recording layer.

24. A method, comprising:
forming an underlayer of a magnetic recording medium, the underlayer comprising:
first encapsulated nanoparticles each comprising a first magnetic nanoparticle encapsulated by a first aromatic polymer, and
a first polymeric binder binding the first encapsulated nanoparticles,

wherein forming the underlayer includes mixing the first encapsulated magnetic nanoparticles with the first polymeric binder for forming a mixture, and
spray coating the mixture onto a structure; and

forming a magnetic recording layer above the underlayer, the magnetic recording layer comprising:
second encapsulated nanoparticles each comprising a second magnetic nanoparticle encapsulated by an encapsulating layer, and
a second polymeric binder binding the second encapsulated nanoparticles,

wherein forming the recording layer includes spray coating a mixture of the second magnetic nanoparticles, a precursor to the encapsulating layer, and polymeric binder onto the underlayer.

25. The method as recited in claim 24 , wherein the underlayer is electrically conductive.

Assignees

• IBM

Inventors

• Bradshaw Richard

Classifications

• C09D5/00

  Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced {(electrically insulating plastics, resins or waxes H01B3/30)}; Filling pastes · CPC title

• C09D7/62

  modified by treatment with other compounds · CPC title

• C09D7/67

  Particle size smaller than 100 nm · CPC title

• C09D7/65

  macromolecular (C09D7/41-C09D7/48 take precedence) · CPC title

• G11B5/008

  Recording on, or reproducing or erasing from, magnetic tapes, {sheets, e.g. cards,} or wires (G11B15/00 {G11B19/00} take precedence; {bulk transferring of information magnetisation for re-recording G11B5/865; marking record carriers in digital fashion G06K}) · CPC title