Monodisperse lubricant including multidentate perfluoropolyether structures

Patent metadata

Field	Value
Publication number	US-9765273-B2
Application number	US-201414480552-A
Country	US
Kind code	B2
Filing date	Sep 8, 2014
Priority date	Sep 8, 2014
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

In one embodiment, a method for forming a substantially monodisperse lubricant includes: providing a plurality of perfluoropolyether (PFPE) precursors, each PFPE precursor including two end segments and a PFPE backbone disposed therebetween; protecting one of the end segments of each PFPE precursor with one or more protecting agents to form a plurality of mono-protected PFPE precursors, each mono-protected PFPE precursor including a protected end segment and an unprotected end segment; and coupling the unprotected end segment of each of the mono-protected PFPE precursors to the unprotected end segment of another of the mono-protected PFPE precursors via a coupling agent to form multidentate PFPE structures. In another embodiment, a substantially monodisperse lubricant includes a plurality of multidentate perfluoropolyether (PFPE) structures, each multidentate PFPE structure including at least two end segments and a middle segment therebetween, wherein the multidentate PFPE structures have a molecular weight that is substantially the same.

First claim

What is claimed is:

1. A method for forming a substantially monodisperse lubricant,
comprising:
providing a plurality of perfluoropolyether (PFPE) precursors, each PFPE precursor including two end segments and a PFPE backbone disposed therebetween;
protecting one of the end segments of each PFPE precursor with one or more protecting agents to form a plurality of mono-protected PFPE precursors, each mono-protected PFPE precursor including a protected end segment and an unprotected end segment; and
coupling the unprotected end segment of each of the mono-protected PFPE precursors to the unprotected end segment of another of the mono-protected PFPE precursors via a coupling agent to form multidentate PFPE structures.

2. The method as recited in claim 1 , wherein at least one end segment of at least one PFPE precursor is represented by:

wherein each X is independently selected from a group consisting of: a hydroxyl group, a piperonyl group, an amine group, a phosphazene group, and a combination thereof.

3. The method as recited in claim 1 , wherein the PFPE backbone of at least one PFPE precursor comprises at least one perfluoroethyl ether unit represented by:
—(CF 2 CF 2 O) n —,

where n is an integer greater than zero.

4. The method as recited in claim 1 , wherein the PFPE backbone of at least one PFPE precursor comprises at least one perfluoropropyl ether unit represented by:
—(CF 2 CF 2 CF 2 O) n —,

where n is an integer greater than zero.

5. The method as recited in claim 1 , wherein the PFPE backbone of at least one PFPE precursor has a molecular weight in a range between about 300 amu to about 5000 amu.

6. The method as recited in claim 1 , wherein each end segment of at least one PFPE precursor includes at least one reactive functional group configured to attach to a surface.

7. The method as recited in claim 6 , wherein the at least one reactive functional group is a hydroxyl.

8. The method as recited in claim 6 , wherein the at least one reactive functional group is selected from a group consisting of: a hydroxyl group, a piperonyl group, an amine group, a carboxylic acid, a phosphazene group, and a combination thereof.

9. The method as recited in claim 6 , wherein the one or more protecting agents in each protected end segment are configured to protect the at least one reactive functional group present therein.

10. The method as recited in claim 6 , wherein each end segment of at least one PFPE precursor includes two reactive functional groups configured to attach to a surface.

11. The method as recited in claim 1 , wherein the plurality of mono-protected PFPE precursors include: mono(acetonide)-protected PFPE precursors; mono(carbonate)-protected PFPE precursor; mono(thiocarbonate)-protected PFPE precursors; and combinations thereof.

12. The method as recited in claim 1 , wherein at least one of the multidentate PFPE structures includes eight reactive functional groups configured to attach to a surface.

13. The method as recited in claim 12 , wherein each of the eight reactive functional groups include a hydroxyl group.

14. The method as recited in claim 1 , wherein the multidentate PFPE structures have a molecular weight that is substantially the same wherein the PFPE structures have a polydispersity index of 1 to 1.5.

15. The method as recited in claim 1 , further comprising removing at least one of the protecting agents from at least one of the multidentate PFPE structures.

16. A method for preparing a magnetic recording medium, the method comprising,
applying a lubricant layer to a surface of a magnetic recording medium using a deposition technique selected from a group consisting of: dip coating, spin coating, spray coating, and combinations thereof,
wherein the lubricant layer is comprised of a plurality of monodisperse multidentate perfluoropolyether (PFPE) structures,
wherein each of these multidentate PFPE structures has two end segments and a middle segment disposed therebetween,
wherein the middle segment of each multidentate PFPE structure comprises at least two PFPE backbones coupled together via a coupling group,
wherein the multidentate PFPE structures have a molecular weight that is substantially the same, and
wherein the PFPE structures have a polydispersity index of 1 to 1.5.

17. A substantially monodisperse lubricant, comprising:
a plurality of multidentate perfluoropolyether (PFPE) structures, each multidentate PFPE structure including at least two end segments and a middle segment therebetween,
wherein the multidentate PFPE structures have a molecular weight that is substantially the same,
wherein the PFPE structures have a polydispersity index of 1 to 1.5.

18. The lubricant as recited in claim 17 , wherein at least one end segment of at least one multidentate PFPE structure is represented by:

wherein each X is independently selected from a group consisting of: a hydroxyl group, a piperonyl group, an amine group, a phosphazene group, and a combination thereof.

19. The lubricant as recited in claim 17 , where the middle segment of at least one multidentate PFPE structure comprises at least two PFPE backbones coupled together via a coupling group.

20. The lubricant as recited in claim 19 , where at least one of the PFPE backbones is represented by:
—(CF 2 CF 2 O) n —,

where n is an integer greater than zero.

21. The lubricant as recited in claim 17 , wherein each end segment of each multidentate PFPE structure includes at least one reactive functional group configured to attach to a surface, wherein the at least one reactive functional group is selected from a group consisting of: a hydroxyl group, a piperonyl group, an amine group, a carboxylic acid, a phosphazene group, and a combination thereof.

22. The lubricant as recited in claim 17 , wherein at least one end segment of at least one of the multidentate PFPE structures includes at least one protecting agent.

23. The lubricant as recited in claim 22 , wherein the at least one protecting agent is selected from a group consisting of: an acetonide; a carbonate; and a thiocarbonate.

24. A magnetic recording medium, comprising:
a magnetic recording layer positioned above a non-magnetic substrate;
a protective overcoat positioned above the magnetic recording layer; and
a lubricant layer positioned above the protective overcoat, the lubricant layer comprising the lubricant as recited in claim 17 .

25. A magnetic data storage system, comprising:
at least one magnetic head;
the magnetic recording medium as recited in claim 24 ;
a drive mechanism for passing the magnetic recording medium over the at least one magnetic head; and
a controller electrically coupled to the at least one magnetic head for controlling operation of the at least one magnetic head.

Assignees

• Western Digital Tech Inc

Inventors

• Conley Nicholas R
• Kong Xueqian
• Marchon Bruno

Classifications

• C10M107/38 Primary

  containing halogen · CPC title

• C10M2213/043

  used as base material · CPC title

• C10N2040/18

  in connection with recordings on magnetic tape or disc · CPC title

• C10N2020/075

  Dendrimers · CPC title

• G11B5/8408

  protecting the magnetic layer · CPC title