Cutlery – Razors – Combined
Reexamination Certificate
2000-12-14
2001-10-09
Payer, Hwei-Siu (Department: 3724)
Cutlery
Razors
Combined
C030S050000, C030S081000, C424S073000
Reexamination Certificate
active
06298559
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a shaving aid strip (or composite) for a razor cartridge.
It is now well known that shaving comfort can be enhanced by affixing to a razor cartridge a shaving aid composite, also known as a lubricating strip, which continuously releases a shaving aid, typically a lubricant, during the shaving process. See, for example, U.S. Pat. No. 4,170,821 and GB 2,024,082. The shaving aid strip generally comprises a water-insoluble polymer matrix, typically polystyrene, and a water-soluble shaving aid, typically polyethylene oxide, which leaches out of the composite during shaving to enhance shave comfort.
Unfortunately, conventional shaving aid strips suffer from the disadvantage that they release an insufficient amount of the shaving aid, particularly after the first four or five shaves where release of the shaving aid may drop off to negligible quantities. In addition, the amount of shaving aid that may be included in the shaving aid strip may be limited because high levels of shaving aid are difficult to process and can adversely affect the structural integrity of the strip. Accordingly, recent efforts have been made to improve shaving aid strips so as to enhance and prolong release of the shaving aid.
Such efforts have resulted in improved shaving aid strips which include the following features: incorporation of a low molecular weight release enhancing agent, such as polyethylene glycol, into the matrix (U.S. Pat. No. 5,113,585); the use of ethylene vinyl acetate copolymer as the matrix material (U.S. Pat. No. 5,349,750); incorporation of a compatibilizer material such as polyethylene oxide-polypropylene oxide copolymer (e.g. Poloxamer 182) (U.S. Pat. No. 5,454,164); incorporation of a water-swellable polymer such as Salsorb 84, a cross-linked polyacrylic (U.S. Pat. No. 5,626,154); coextrusion of a core comprising a water-leachable shaving aid within a sheath of water-insoluble polymer, wherein the sheath has a plurality of openings to facilitate release of the shaving aid (WO 96/13360, which corresponds to U.S. Ser. No. 08/497,194); and coextrusion of adjacent shaving aid portions (U.S. Pat. No. 5,956,848). Also known are shaving aid strips which include an essential oil (U.S. Pat. No. 5,095,619) or a non-volatile cooling agent (U.S. Pat. No. 5,713,131), and injection molded strips which include a plasticizer (U.S. Pat. No. 4,850,106). All of the aforementioned patents or published applications are incorporated herein by reference.
SUMMARY OF THE INVENTION
The present invention is directed to a razor cartridge with a solid polymeric shaving aid strip. The razor cartridge has a blade (one or more) and a skin-engaging portion in proximity to the blade. The skin-engaging portion includes a solid polymeric shaving aid strip having an upper exposed surface which contacts the skin during shaving. The shaving aid strip includes a first exposed lengthwise-extending portion containing a lubricious water-soluble polymer and an adjacent, second exposed lengthwise-extending portion containing a lubricious water-soluble polymer. The first portion contains a greater amount of the lubricious water-soluble polymer than the second portion, and the first portion is adapted to wear at a faster rate than the second portion during shaving. This construction enables the strip to release more of the lubricious water-soluble polymer for a longer time period (i.e., for more shaves) than conventional shaving aid strips.
The shaving aid strip is typically located at the rear (or cap) portion of the cartridge (i.e. behind the blade or blades), but may also be located at the front (or guard) portion of the cartridge (i.e., in front of the blade or blades), or a shaving aid strip may be placed at both positions on the cartridge. The razor cartridge is generally affixed to a handle for use in shaving. The razor cartridge may be designed to be removably affixed to a handle in the case of razor systems in which the handle is reused and the cartridge is disposed of after one or more uses. Or the razor cartridge may be permanently affixed to a handle (or integral with the handle) in the case of disposable razors in which the handle and cartridge are disposed of together as a unit after one or more uses. The term razor cartridge is thus intended to apply to both types of cartridge.
REFERENCES:
patent: 4170821 (1979-10-01), Booth
patent: 4850106 (1989-07-01), Braun et al.
patent: 5095619 (1992-03-01), Davis et al.
patent: 5113585 (1992-05-01), Rogers et al.
patent: 5345680 (1994-09-01), Veerland et al.
patent: 5349750 (1994-09-01), Tseng
patent: 5430939 (1995-07-01), Johnston
patent: 5454164 (1995-10-01), Yin et al.
patent: 5626154 (1997-05-01), Rogers et al.
patent: 5713131 (1998-02-01), Rogers et al.
patent: 5956848 (1999-09-01), Tseng et al.
patent: 5956849 (1999-09-01), Chadwick et al.
patent: 6185822 (2001-02-01), Tseng et al.
patent: 2024082 (1980-01-01), None
patent: WO-96/13360 (1996-05-01), None
Kwiecien Michael J.
Walker, Jr. Vincent P.
Payer Hwei-Siu
The Gillette Company
Williams Stephan P.
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