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Publication numberUS3743551 A
Publication typeGrant
Publication dateJul 3, 1973
Filing dateApr 14, 1971
Priority dateApr 17, 1970
Also published asCA927224A1, CA989687A1, DE2118211A1, DE2118211B2, DE2118212A1, US3774703
Publication numberUS 3743551 A, US 3743551A, US-A-3743551, US3743551 A, US3743551A
InventorsM Sanderson
Original AssigneeWilkinson Sword Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Razor blades and methods of manufacture thereof
US 3743551 A
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Description  (OCR text may contain errors)

United States Patent 3,743,551 RAZOR BLADES AND METHODS OF MANUFACTURE THEREOF Michael D. Sanderson, Egham, England, assignor to Wilkinson Sword Limited, London, England No Drawing. Filed Apr. 14, 1971, Ser. No. 140,186 Claims priority, application Great Britain, Apr. 17, 1970, 18,409/ 70 Int. Cl. B26b 21 /54 US. Cl. 148-63 12 Claims ABSTRACT OF THE DISCLOSURE On a razor blade having at least one cutting edge there is provided a first coating of chromium, whose surface region may be oxidised, upon which is superposed a second coating of chromium nitride. A coating of a polymer which improves the shaving properties of the blade may be provided on the chromium nitride coating.

This invention relates to razor blades and to methods of manufacture thereof.

It is known to provide a coating of chromium on the cutting edge of a razor blade and to coat the chromium with polytetrafluoroethylene.

According to the present invention there is provided a razor blade wherein at least a cutting edge has an upper coating of chromium nitride superposed on a lower coating of chromium.

Preferably the surface region of the lower coating is chromium oxide.

The invention also provides the method of manufacturing a razor blade wherein at least a cutting edge is coated with chromium and the chromium coating is thereafter provided with a coating of chromium nitride.

Preferably the upper coating is provided with a coating of a polymer which improves the shaving properties of the blade and may, for example comprise a fluorocarbon polymer, for example polytetrafiuoroethylene or a copolymer of thiocarbonyl fluoride and tetrafluoroethylene.

Thus, in a preferred form of the invention the blade is first provided with a chromium coating on the cutting edge, thereafter a chromium nitride coating is superposed on the first coating and, finally, a polymer coating is provided on the nitride coating.

One method of providing a stainless steel razor blade with a double coating in accordance with the present invention is, tfilSt, to form a chromium coating by sputtering chromium onto the previously cleaned cutting edges from electroplated targets at a pressure of between A of a micron and 10 microns of mercury in a residual atmosphere of inert gas such as argon or helium using commercially available ion-plasma sputtering apparatus. The chromium coating may, for example, be of a thickness between 50 and 450 angstroms but preferably not greater than 200 angstroms. Thereafter the sputtering process is repeated with a residual atmosphere of nitrogen at a pressure of, for example, 1 to 4X10 millimetres of mercury, to form a chromium nitride coating.

Preferably, the blades are exposed to an oxide-forming atmosphere after formation of the initial coating so that the surface region of the initial coating is oxidised. One way of achieving this is by allowing a controlled air leak into the sputtering apparatus between the two coating stages.

3,743,551 Patented July 3, 1973 p CC I The nitride coating may have a thickness of, for example, from 50 to 450 angstroms but preferably not greater than 150 angstroms and a preferred range for the thickness of the two coatings together is from to 500 angstroms or even up to 750 angstroms.

The term nitride is intended to embrace coatings over the range from a small amount of nitrogen in solid solution with chromium up to any of the chromium nitride compounds, Cr N, Cr N and ON, or any combination thereof. Thus for example the composition range may extend from 0.01 atomic percent nitrogen to 55 atomic percent nitrogen.

The reaction between chromium and nitrogen in the sputtering process may take place on the surface of the target, or as the metallic particles are being sputtered through the ionised nitrogen plasma or after the metal has been deposited on the blade surface.

The gas composition can vary widely depending upon the sputtering conditions. Thus, for example, the nitrogen may be diluted with an inert gas, such as argon, from 5 volume percent of the gas in argon to 100 volume percent of the nitrogen or other gas. Alternatively a gas with a large nitrogen content such as cracked ammonia and/ or air diluted by an inert gas may be used.

The sputtering may be direct current or radio frequency sputtering and in the latter case sputtering may be direct from a chromium nitride target in an inert atmosphere.

As an alternative to sputtering the coatings may be produced by chemical vapour deposition or by reactive evaporation.

I claim:

1. A razor blade wherein at least a cutting edge has an upper coating of chromium nitride superposed on a lower coating of chromium.

2. A razor blade according to claim 1, wherein the surface region of said lower coating is chromium oxide.

3. A razor blade according to claim 1, wherein each coating has a thickness of between 50 and 450 angstroms.

4. A razor blade according to claim 1, wherein said lower coating has a thickness of between 70 and 200 angstroms.

5. A razor blade according to claim 1, wherein said upper coating has a thickness of between 50 and angstroms.

6. A razor blade according to claim 1, wherein a coating of a shaving facilitating polymer is provided on said upper coating.

7. A razor blade according to claim 1, wherein a coating of a fluorocarbon polymer is provided on said upper coating.

8. A razor blade according to claim 1, wherein a coating of polytetrafluoroethylene is provided on said upper coating.

9. A razor blade according to claim 1, wherein a coating of a copolymer of thio-carbonyl fluoride and tetrafluoro'e'thylene is provided on said upper coating.

10. The method of manufacturing a razor blade wherein at least a cutting edge is coated with chromium and the chromium coating is thereafter provided with a coating of chromium nitride.

11. The method according to claim 10, wherein at least the surface region of the initial chromium coating is oxidised.

12. The method according to claim 10, wherein each 6618472 3/1967 Netherlands 30346.53

coating is applied by ion-plasma sputtering. 1,200,165 7/ 1970 Great Britain 148--16.6

References Cited OTHER REFERENCES UNITED STATES PATENTS 5 Chem. Abstracts, vol. 67: 35237t (1967).

3,480,483 11/1969 Wilkinson 1486.3 1 94 025 1 1934 Frost 14 1 RALPH KENDALL, Prlmary Examlner FOREIGN PATENTS 1,193,067 5/1970 Great Britain 30 346 54 10 30-346.54; 29-195, 196.6; 14816.6; 204-192; 117

1,065,724 4/1967 Great Britain 30346.54 71 M

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3811189 *Mar 19, 1973May 21, 1974Gillette CoProcess for producing an improved cutting tool
US3871836 *Dec 20, 1972Mar 18, 1975Allied ChemCutting blades made of or coated with an amorphous metal
US3960608 *Aug 2, 1973Jun 1, 1976Wilkinson Sword LimitedRazor blades
US4071382 *Jul 22, 1976Jan 31, 1978Midland-Ross CorporationMethod for case hardening powdered metal parts
US4411964 *Dec 17, 1981Oct 25, 1983Nippon Kokan Kabushiki KaishaComposite coating steel sheets having good corrosion resistance paintability and corrosion resistance after paint coating
US4683043 *Jan 21, 1986Jul 28, 1987Battelle Development CorporationCubic boron nitride preparation
US4744679 *Sep 15, 1986May 17, 1988Skf Industrial Trading And Development Co. B.V.Plastic cage for a rolling bearing
US4919773 *Jun 8, 1988Apr 24, 1990Avco CorporationMethod for imparting erosion-resistance to metallic substrates
US5232568 *Jun 24, 1991Aug 3, 1993The Gillette CompanyRazor technology
US5648178 *Dec 28, 1994Jul 15, 1997Chevron Chemical CompanyReactor system steel portion
US5669144 *Nov 7, 1995Sep 23, 1997The Gillette CompanyRazor blade technology
US6258256Jan 4, 1994Jul 10, 2001Chevron Phillips Chemical Company LpCracking processes
US6274113Jul 28, 1999Aug 14, 2001Chevron Phillips Chemical Company LpOperating steam reforming in steam reforming reactor system at a first steam to carbon ratio; providing protective layer to portion of steam reforming reactor system to reduce by-products; operating steam reforming
US6419986Jan 10, 1997Jul 16, 2002Chevron Phillips Chemical Company IpSupplying getter; removal; fixing
US6551660Apr 18, 2001Apr 22, 2003Chevron Phillips Chemical Company LpMethod for removing reactive metal from a reactor system
US6602483Jun 21, 2001Aug 5, 2003Chevron Phillips Chemical Company LpIncreasing production in hydrocarbon conversion processes
US6684513 *Feb 29, 2000Feb 3, 2004The Gillette CompanyRazor blade technology
US6866894Jul 10, 2002Mar 15, 2005The Gillette CompanyOuter layer of polytetrafluoroethylene coating over the overcoat, applied from aqueous solution
US7673541 *Jun 3, 2004Mar 9, 2010The Gillette Companydepositing an oxide coating prior to heat treatment of the blade material and heat treating under conditions selected to enhance the color of the coating.
US7966909Jul 25, 2007Jun 28, 2011The Gillette CompanyProcess of forming a razor blade
US8505414Jun 17, 2009Aug 13, 2013Stanley Black & Decker, Inc.Method of manufacturing a blade
US20100299931 *May 26, 2009Dec 2, 2010Krassimir Grigorov MarchevStrengthened razor blade
USRE29989 *Mar 15, 1977May 8, 1979Allied Chemical CorporationCutting blades made of or coated with an amorphous metal
WO2001064406A2 *Feb 27, 2001Sep 7, 2001Colin John ClipstoneRazor blade technology
WO2005005110A1 *Jul 8, 2004Jan 20, 2005Ype B BradaA coated cutting member having a nitride hardened substrate
Classifications
U.S. Classification428/623, 148/277, 148/222, 204/192.16, 428/627, 428/632, 428/626, 428/932, 30/346.54, 428/667
International ClassificationC23C16/34, C23C14/16, B26B21/58, B26B21/54, B26B21/60
Cooperative ClassificationB26B21/60, B26B21/54, B26B21/58, Y10S428/926, Y10S428/932
European ClassificationB26B21/58, B26B21/60, B26B21/54