Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
1998-11-05
2001-01-16
Krynski, William (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S364000, C428S398000, C428S400000, C015S159100
Reexamination Certificate
active
06174600
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to synthetic bristles having a number of the advantages of natural (e.g., hog's hair) bristles but without certain attendant disadvantages, such as uncontrollable or irregular cross-section, high cost and inconsistent availability. This invention also relates to brushes employing such bristles.
The bristles of this invention employ particulates in a manner to provide an irregular and/or roughened surface, and are particularly well-suited for use in paintbrushes. However, the bristles are believed to have desirable attributes for use in other applicator brushes, e.g., scrub brushes, with or without the use of cleaning/scrubbing compounds or ingredients, and the like. In addition, the bristles of this invention also are believed to have desirable attributes for other brushes, such as beater brushes in vacuum cleaners.
BACKGROUND OF THE INVENTION
Microcellular synthetic bristles formed by the use of a blowing agent to form closed cells in the interior of the bristles and ruptured cells at the surface are known in the prior art, as exemplified by the teachings in U.S. Pat. No. 4,937,141 (Burns); U.S. Pat. No. 5,022,112 (Burns); U.S. Pat. No. 5,032,456 (O'Brien et al.) and U.S. Pat. No. 5,151,229 (Burns). The subject matter of all of the aforementioned patents is fully incorporated herein by reference.
Although the use of blowing agents in the manufacture of bristles has resulted in the formation of irregularities (i.e., provided by open cells) on the surface of the bristles, thereby simulating the desirable surface characteristics of natural bristles, the substantial randomness of such irregularities has made it difficult to provide a desired percentage of the bristles with a desired degree of such surface irregularity. Thus, a number of the formed bristles have surfaces that are so smooth, or have such extremely limited surface irregularities, that the desired benefits of a rough, irregular surface are not achieved.
Moreover, bristles formed only with blowing agents have not had the desired bend recovery characteristics for applications in which the bristles are subjected to high bending forces, and therefore crack, crimp, or often break, or often do not recover do to lack of stiffness.
In addition, although employing a blowing agent to form bristles does result in a lower bulk density than forming the bristles without such a blowing agent, a need still exists for bristles of even lower bulk density, but without detracting from other desirable characteristics of the bristles.
In addition, bristles formed solely with a blowing agent, or without a blowing agent, often are difficult to handle in brush forming equipment, due to the fact that the individual filaments do not easily flow relative to each other and therefore tend to move in clumps to the picker unit to interfere with the precise picking and placement of the bristles in the brushes.
SUMMARY OF THE INVENTION
A synthetic bristle in accordance with this invention includes a substantially continuous phase of polymer with spaced-apart microparticles in the interior thereof, at least some of said microparticles being close to the surface thereof for creating rough and irregular surface regions; one or more of which may be created by a crater in the outer surface.
In the preferred embodiment of this invention the microparticles include substantially spherical particles, e.g., hollow glass spheres, solid glass beads, hollow ceramic spheres and solid ceramic spheres; with the most preferred form of the invention including hollow glass spheres.
Preferably the continuous phase of polymer in the synthetic bristle defines closed cells surrounded by polymer and being interspersed with the microparticles in the interior of the bristle, with the closed cells being provided by a blowing agent.
In a preferred embodiment of this invention the rough and irregular surface regions include a surface of at least one of said microparticles and/or a raised polymer surface overlying at least one of said microparticles.
In a preferred embodiment of this invention the rough and irregular outer surface includes multiple craters, at least one of said craters being formed as an open cell by a blowing agent and at least one of said craters being formed by an escaped microparticle.
A brush in accordance with a preferred embodiment of this invention includes a handle and a bundle of bristles, at least 5% of said bristles being synthetic bristles including a substantially continuous phase of polymer with spaced-apart microparticles in the interior thereof, at least some of said microparticles being close to the surface thereof for creating rough and irregular surface regions.
Most preferably the continuous phase of polymer in bristles in the brush defines closed cells surrounded by polymer and being interspersed with the microparticles in the interior of said bristle, said closed cells being provided by a blowing agent.
REFERENCES:
patent: 5679067 (1997-10-01), Johnson et al.
Brown James M.
Collins Joseph M.
Huskey Tom R.
Prawdzik David
Caesar, Rivise, Bernstein, Cohen & Pokotilow, LTD
Gray J. M.
Krynski William
Speciality Filaments, Inc.
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