US 3831218 A
An improved brush construction wherein the bristled head is secured to the handle by means of a band and fastening means inserted therethrough, the improvement comprising a handle being prepared from a foamed fiber reinforced thermoplastic resin.
Description (OCR text may contain errors)
United States Patent [191 Kaplan 1 Aug. 27, 1974 [5 BRUSH CONSTRUCTION 3,425,084 2/1969 s1v Laurence ct a1. 15/195  Inventor: Ronald Kaplan, 104 Fairway Ave.,
Verona, NJ. 07044 Filed: Feb. 27, 1973 Appl. No.: 336,184
US. Cl. 15/192, 15/143 R Int. Cl A46b 3/02 Field of Search 15/191, 192, 193, 194,
References Cited UNITED STATES PATENTS 11/1959 Hardman ct a1. 15/192 Primary ExaminerPeter Feldman ABSTRACT ment comprising a handle being prepared from a foamed fiber reinforced thermoplastic resin.
6 Claims, 2 Drawing Figures This invention relates to a brush construction exhibiting numerous improvedcharacteristics stemming from the use of fiber reinforced thermoplastic foam resins as the handle material.
Brushes generally consist of bristling filament, a retaining metal band and a handle. The head, which comprises bristles inserted into the metal band and adhesively secured thereto is, in turn, secured to the handle by means of adhesives, crimps and/or. nails.
As is well known, most handles are prepared from wood although several disadvantages are encountered in the use thereof. Thus, wood is very responsive to changes in temperature as well as to contact with aqueousand organic solvent systems. A significant result of this sensitivity is the swelling and contracting of the holes which house the fastening means thereby permitting the fastening means to extractthemselves from the handle and ruin the brush construction. Solvents also adversely affect the wood handle insofar as they tend to cause peeling of the paint coating thereon resulting in an unsightly, rough exterior surface.
Furthermore, wooden handles tend to split .during several of the steps in the brush manufacturing operation. For example, handles are frequently painted by being nailed to an elongated shaft which is subsequently dipped into the paint. It has been observed that a sufficiently large number of handles split as a result of this nailing operation. Likewise, when theretaining metal bands are nailed to the wooden handles, a certain amount of handle splitting is encountered. Other po' tential difficulties with wood include lack of internal strength and high cost of manufacture.
In an effort to overcome these disadvantages, various plastic materials such as polypropylene, phenolic laminates, and the like have been used to prepare brush handles. While these materials have exhibited certain advantages such as reduced cost and increased ease of manufacture, they nevertheless still exhibit many of the disadvantages encountered with wood. Thus, they do not solve the problem of retention of the fastening means, the holes for retaining such fasteners having a smooth and substantially frictionless interior surface which does not allow for maximum retention and also being subject to expansion and contraction upon exposure to external stimuli. Furthermore, such plastics exhibit higher densities than wood, limited internal strength and smooth exterior surfaces which are not conducive to firm, non-slip grasping.
It is the prime object of this invention to provide brush handles which substantially overcome the difficulties encountered with prior art handles.
It is another object of the invention to provide handles which exhibit the desired characteristics of wood handles, namely, appropriate density and exterior surface characteristics.
It is still another object to provide handles which exhibit outstanding retentivity of fastening means inserted therein.
It is a further object to provide handles which exhibit ease and economy of manufacture.
I have now surprisingly determined that the use of a foamed fiber reinforced thermoplastic resinous mate rial to prepare brush handles substantially overcomes all of the disadvantages of the prior art handles while still retaining the beneficial characteristics of wooden handles. Thus, it is possible to achieve desired densities as well as grainy surface characteristics thereby providing the appropriate weight and surface for ready use. Furthermore, the latter property is achieved as part of the manufacturing process without the need for extraneous abrading of the handle surface or the interior of the mold. The handles exhibit excellent internal strength. Of greatest importance and most unexpectedly, the handles of this invention provide superior retentivity of the fastening means which are utilized to affix the bristled head to the handle. It has thus been determined that the reinforcing fibers engage the fastening means so as to prevent the ready extraction of said fastening means. External stimuli therefore, have no effect on such retentivity, the useful life of the brush thereby being substantially increased.
Furthermore, the ease and economy of manufacture of the handles is exceptional. Conventional molding techniques, such as injection molding, utilizing conventional molds are readily applicable. Process modifications relating to operating temperatures or mold inter- .ior are not required. The handle splitting which is en countered with wood handles during brush assembly andpainting is substantially eliminated with the instant handles. Likewise, the painted surface of the handle does not peel or strip upon contact with conventional solvents.
To the accomplishment of the above, and to such other objects as may hereinafter appear, the present invention relates to an improved brush construction as defined in the appended claims, and as described in this specification, taken together with the accompanying drawings, in which:
FIG. 1 is a view, in perspective, of a typical brush construction of this invention; and
FIG. 2 is a view, partly in section and partly in elevation, taken along line 22 of FIG. 1 depicting the manner in which the reinforcing fibers engage the fastening means to substantially increase the retentivity thereof.
The handles of the novel brush construction of this invention can be prepared from virtually any thermoplastic material which can be foamed with a blowing agent and reinforced with glass fibers and the like. Typical thermoplastic resins include aliphatic-olefin polymers such as polyethylene, polypropylene, polybutene, and the like; vinyl halide and vinylidene halide homoand copolymers such as polyvinyl. chloride and polyvinylidene chloride; styrene polymers such as polystyrene; polyamides; polycarbonates; and homoand co polymers of derivatives of acrylic and methacrylic acids such as acrylonitrile-butadiene-styrene and styreneacrylonitrile. The choice of the particular resin will depend on the desired physical characteristics of the resulting handle as well as on its end use application.
It is conventional to form a foamed plastic structure by mixing the resin material with a suitable foaming agent compatible with the resin being employed. The art of producing foamed plastics has advanced to a stage where many such foaming agent-plastic combinations are known. Insofar as the foamed structure per se is concerned, it may in general be formed in any known manner. It may be caused to expand and foam within an enclosed space such as a mold or container in which casethe handle structure will assume the configuration of the inside of that mold or container. In all cases the end product comprises a foam made up. of a plurality of cells defined by portions of the resinous material which form cell walls. Depending upon the procedures employed, the individual cells may communicate with one another or not, but in either event the end structure is cellular and consists of voids surrounded by relatively thin plastic walls. The sizes of the cells will not be exactly the same, but for a given set of process conditions, the cells which are formed will generally be of a particular nominal size.
Known blowing agents which are applicable herein include azo compounds, nitroso compounds, hydrazides, acid azides, guanyl compounds, bicarbonates, 1,- 2-di-chlorotetrafluoroethane, and the like. The foamable resinous composition may also contain a variety of extraneous materials such as foaming accelerators, stabilizers, pigments, plasticizers, fillers, and the like.
Lastly, reinforcing fibers are incorporated into the foamable resinous mass before foaming, the dimensions of the fibers generally being closely related to the dimensional characteristics of the end foamed structure. The fibers tend to distribute themselves uniformly and randomly in all directions throughout the end structure and to be substantially completely contained within the resinous materials defining the cell walls. Thus, the fiber is bound to the resin in order to efficiently improve tensile strength in the direction in which it extends.
While in most instances, glass reinforcing fibers are utilized in the unique handles of this invention, it should be noted that the use of other fibers such as as bestos, graphite, cellulose, metal and quartz is also con templated as falling within the scope of the invention. Fiber lengths are to be determined by the practitioner in accordance with his particular requirements, although as a practical matter, it is extremely difficult to ensure that one is dealing with fibers all of which fall within particular dimensional restrictions. The fiber concentration in the resinous material will generally vary from about 5 to 50 percent, by volume relative to the thermoplastic material.
Methods for foam formation are well known to those skilled in the art and, accordingly, do not form any part of the subject invention. The preferred method for purposes of this invention is injection molding. This technique generally involves feeding the foamable reinforced thermoplastic resin, usually in pellet form, into a heating cylinder. With successive strokes of a revolving screw or injection ram, the material is compacted and forced forward into a thin annular space between the heating mechanism and the cylinder walls. There the material is melted. At this point the blowing agent begins to give off gas. As bubbles begin to form, the polymer melt reaches its processing temperature, this temperature, of course, depending on the specific blowing agent-resin system being used. The molten material is then injected into the cold mold cavity, the speed of injection being fast enough to keep the melt from decompressing completely and from cooling too rapidly. The melt then undergoes free expansion in the mold cavity which is shaped to the contours of the finished product. As the melt expands, it is cooled by the mold until the skin formed is firm enough to withstand the internal pressure. Cooling may be accomplished by water circulation, although some mold heating may be required to increase flow and mold surface reproduction. The cooled, molded handle is then ejected.
It is seen that the handle exhibits excellent internal strength, appropriate specific gravity generally ranging from about 0.60 to 0.70, and excellent surface characteristics typical of wood grain finishes. The latter property is achieved as part of the molding operation rather than by means of extraneous abrading techniques or by roughing the interior surface of the mold cavity.
Methods for manufacturing the final brush construction are also well known to those skilled in the art. Thus, as depicted in FIG. 1, the head which comprises bristles l0 and wooden or plastic plug 12 inserted into retaining band 16 and adhesively secured therein as by epoxy adhesive, and the handle 14 are combined by inserting handle 14 into the opposing end of band 16 and fastening the handle 14 to the band 16 by fastening means 18 such as nails, brads and the like. Fastening may also be facilitated by a crimp assembly (not shown) wherein indented sections or corners and/or lengths of the band 16 penetrate the surface of handle 14 to provide greater surface contact between the band 16 and the handle 14. The crucial aspect of the fastening operation is that the fastening means 18 are sub stantially permanently secured in handle 14. Thus, upon entering handle 14, the fastening means 18 displace the fibers and then are immediately surrounded 'by the displaced fibers as a result of the resiliency thereof. The fibers thus serve to retain fastening means 18 in handle 14. Retention may be further facilitated by the presence of barbs or recessed'annulations on the shank of fastening means 18 which permits the fibers to intertwine with and physically hold fastening means 18 in place.
The manner in which said fastening means are firmly secured in the fiber reinforced handle is shown in FIG. 2. It is seen that handle 14 is formed of a thermoplastic material in the form of walls 20 surrounding voids 22, thereby to produce cells. As the drawing indicates, fibers 24 are located within the cell walls 20 along their entire length and are randomly distributed and oriented. Skin 26 which forms the exterior surface of han dle 14 comprises a dense, substantially unfoamed matrix of fibers. Fastening means 18 penetrate handle 14 displacing fibers 24 along the path of penetration, primarily the matrix of glass fibers in skin 26. The fibers 24 seek to return to their original position as a result of their inherent resiliency, thereby surrounding and engaging fastening means 18 preventing their ready re-v moval from handle 14. As indicated, primary retention of fastening means 18 is effected by the dense matrix of fibers which comprise skin 26. The presence of annulations 28 on said fastening means 18 facilitates the retention thereof inasmuch as the fibers 24 may become entangled in annulations 28 and thus more fixedly secure fastening means 18.
By way of specific illustration, polypropylene in pellet form and containing appropriate blowing and nucleating agents therein along with 20 percent, by volume, glass fiber reinforcement was molded into a suitable handle shape by means of a conventional screw injection molding machine. The melting temperatures utilized ranged from about 300 to 500 F. The resulting handle exhibited a specific gravity of about 0.62, excellent impact strength, a grainy exterior surface and excellent retention of the fastening means which were inserted therein.
Summarizing, the use of foamed fiber reinforced thermoplastic resin to prepare handles represents a novel approach with a number of unanticipated advantages, namely, the improved retention of fastening means therein, the achievement of wood-like densities and surface characteristics, and the like.
While but a limited number of embodiments have been here specifically disclosed, it will be apparent that many variations may be made therein, all within the scope of the present invention as defined in the following claims.
What is claimed is:
1. In a brush construction comprising a bristled head,
a handle, a retaining band securing said head to said handle and positioned to cover the junction between said head and said handle, and fastening means fixedly securing said band to said handle, the improvement comprising a handle of thermoplastic material foamed into a mass of cells defined between variously oriented walls formed of said thermoplastic material and fibers distributed throughout said handle and extending generally in random direction, said fibers engaging the por- 5. The brush construction of claim 3, wherein said fibers are present in proportions by volume relative to said thermoplastic material between 5 and 50 percent.
6. The brush construction of claim 1, wherein re cessed annulations are present on said fastening means.