Method for fabricating a tufted construction

Abstract: Tufts (303) of synthetic material are picked and non-working ends thereof are fused. A thin-walled hollow bottle (300) of synthetic material is molded with protrusions extending from a wall surface thereof with each protrusion intended to receive a fused tuft end. The protrusions are then heat softened to form melted sections of synthetic surface on which the fused tuft ends are mounted. The result is a hollow container having tufts extending from the outer surface thereof, integral with the container without distortion of the thin wall thereof caused by the fusing process.

Description: This invention relates to fused, tufted constructions wherein synthetic filament tufts are fused at non-working ends and integrally attached to a base. In particular this invention relates to a method of preparation wherein said tufted constructions are formed of relatively thin-walled hollow articles wherein the walls are subject to deformation by the heat of fusing. Many different types of brushware articles and methods for their manufacture have been described in the prior art. Traditionally, brushware constructions have tufts which are wire-set, anchor-set, twisted in wire, and resin set, and include both natural and synthetic filament tufts. The method of preparing tufted constructions wherein synthetic filament tufts are fused onto a synthetic support and articles using such techniques are described in my U.S. patents, assigned to the assignee of this invention. For example, U. S. Patents No. 3,604,043; 4,189,189; 4,291,431; 4,348,060; 4,690,277 and 4,693,519 are exemplary and are hereby incorporated by reference. These patents disclose tufted fused brush and mat like devices wherein synthetic filament tufts are fused to molded base sections of synthetic material. In my co-pending Patent Application Serial No. 08/540,504, filed October 10, 1995, there is described the preparation of a tufted construction wherein the material of the base or brush block is heated, and deforms and warps when cooling. The process wherein a heated brush block receives a fused tuft end for mounting produces a warped working surface for the tufted construction. That application describes pre-configuring the brush block to take into consideration the fact that it deforms when it heats, and warps when it cools so that the resulting article is a tufted construction wherein the working ends of the tufts lie in a predetermined configuration to maximize the scrubbing power so that all tuft ends encounter a surface to be cleaned simultaneously. As noted in that application the fusing process causes an originally flat brushware block to take a first curvature when heated and upon cooling causes the block to warp beyond that original profile to a second curvature without outside intervention. Obviously, a warped brush block would not be desirable in that it would require a trimming step for the working ends of the filament tufts or a second heating action on the opposite side of the brush block in a attempt to cause it to reorient its molecular structure. This latter procedure could produce the desired article without trimming. These procedures however are not available when tufts are fused onto a relatively thin walled surface such as containers prepared by conventional blow-molding techniques. EP-A-0,150,785 discloses a method for connecting bristles to a bristle carrier to form a toothbrush. The bristles are heat fused into the surface of a head of the toothbrush or into preformed recesses in that surface. EP-A-0,472,863 discloses apparatus for producing bristle bundles. The bristle bundles are heat fused into the surface of a block-like bristle carrier or into preformed depressions in that surface. At the base of each depression is a projection which projects part of the way up to the surface of the bristle carrier. It is this projection that is heat fused to a corresponding depression in the base of a bristle bundle. SUMMARY OF THE INVENTION According to the present invention, there is provided a method for fabricating a tufted construction by fusing synthetic filament tufts onto the outer surface of a thin-walled synthetic hollow container, comprising: providing a thin-walled synthetic hollow container molded to have an outer wall surface and a plurality of mutually spaced protrusions which are hollow projections extending outwardly in a predetermined pattern from said wall surface; providing a plurality of parallel cut-to-length synthetic filament tufts, each tuft having a non-working end; providing a source of heat and fusing the non-working ends of said tufts and fusing said protrusions of said container until said protrusions collapse into molten plugs at said wall surface; and indexing the fused end of each tuft into a fused protrusion and allowing said fused tuft ends and protrusions to cool whereby said tufts are integrally attached to said container to form said tufted construction. With the present invention, the thin-walled hollow container can have fused tufts attached to the outer surface thereof wherein the outer surface retains its original configuration. Specifically, the container is formed with (e.g. conical) protrusions on the outer surface thereof which are hollow and oriented and aligned in the places desired for the tufts. Each protrusion is then heated until it collapses and a fused tuft end is mounted thereon. In the case of a blow molded bottle or the like, the procedure of the invention is applied to a bottle having a wall thickness from about 0.508mm to 1.27mm (about 0.020 inches to 0.050 inches) so long as the ratio of the height of the raised portion to its width is at least about 0.5. When the tufts and container are made of the same synthetic material, the present invention provides a one component recyclable, non-polluting brushware construction. Preferably, the diameter of each protrusion, prior to fusing, is about the thickness of each tuft. The container portion may be arranged to have liquid loaded therein, so that when the liquid is poured onto a surface the tufts of the tufted construction can be used to work the liquid into the surface. Alternatively the container may dispense dry material. Preferred non-limiting embodiments of the invention will now be described with reference to the accompanying drawings and following description. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side view of an unassembled, conventional, blow-molded hollow container before fusing. Figure 2 is a fragmentary schematic showing an attempt to heat-soften a surface for receiving a fused tuft on the bottle of Figure 1. Figure 3 is a view similar to Fig. 2 showing heat directly applied to fuse the bottle surface. Figure 4 is a view similar to Figs. 2 and 3 after the surface has been fused and prior to mounting the fused end of the tuft thereon. Figure 5 is a view similar to Figs. 2-4 showing the fused tuft mounted on the surface of said container. Figure 6 is a view similar to Fig. 1 of a blow-molded hollow container having protrusions for mounting tufts thereon, according to this invention . Figure 6A is a cross-sectional view taken along lines A - A Figure 6. Figure 6B is a view similar to Fig. 6A after the tufts have been mounted thereon. Figure 7 is a fragmentary cross-sectional view of a portion of the container of Fig. 6 prior to heat softening the protrusion thereon. Figure 8 is a view similar to Fig. 7 illustrating heat softening the protrusion thereon. Figure 9 is a view similar to Fig. 8 showing the fused base prior to receiving the fused tuft end. Figure 10 is a view similar to Figs. 7-9 showing the mounting of a fused tuft end on the container of Fig.6. Figure 11 is a front view of a tufted construction wherein tufts are integrally fused on the outside surface of a blow-molded hollow construction according to this invention. Figure 12 is a side view of the device of Fig. 11. Figure 13 is a fragmentary cross-sectional view of a single protrusion on the bottle of Fig: 6 illustrating the height-to-width ratio thereof. Definitions The term "brushware" as used herein includes any device having a synthetic base which has synthetic filament tufts thereon, is hollow, and is thin-walled and further includes such a base which is blow molded. The base can include a hand placement area, a handle, or a bracket or similar device for attaching a handle. The term "synthetic" as in synthetic filament used herein include filaments which are formed from linear thermoplastic polymers from the group consisting of polystyrene and polystyrene co-polymers, polyvinyl chloride and polyvinyl chloride-acetate co-polymers, polyethylene, polypropylene-polyethylene co-polymers, polyamides, polyesters, and polyurethane. Both oriented and unoriented filament are included. Also various filament cross-sections may be used such as for instance circular, lobular, trifoil, X and Y, triangular, polygonal, star-shaped, and the like. Mixtures of synthetic filaments may be employed in cases where the compositions of the filament are compatible during the fusing operation. Such filaments may have suitable crimp imparted to their length or a portion thereof. Filaments may contain organic or inorganic modifications in order to make them bio-degradable, or self decomposing during or after use in a given period of time. The term "picking" as used herein refers to the formation of filament tufts wherein two or more tufts are formed simultaneously by longitudinally engaging a plurality of cut-to-length filament at the ends and removing said filament simultaneously from a parallel disposed bundle of filaments. Picking devices employed are those of the types disclosed in my prior U.S Patents No. 3,471,202; 3,910,637; 4,009,910 and 4,109,965, which are incorporated herein by reference. The term "recyclable" as used herein refers to brushware made according to the instant invention wherein the container and tufts are made of the same chemically raw materials so that when the brushware is ground it can be reused and recycled. For example, a blow-molded polypropylene bottle having polypropylene tufts fused thereon. With attention to the drawings, in particular to Figure 1, there is depicted a generic, conventional blow-molded polypropylene bottle 100 which has walls approximately 0.508mm (0.020 inches) thick, and an open top with a threaded head portion 101 to accept a cap (not shown), a front flat wall 100' and a back flat wall 100''. A parting line 103 running around the entire side wall and bottom of said bottle is shown also. When the bottle 100 is fused with synthetic filament according to the process described in my above patents, a tuft of synthetic filaments has the non-working end fused and the outside surface of the bottle 100 is similarly heat softened. As is known to those skilled in the art this will open a hole in the outside surface of bottle 100 or cause the surface to distort because of the relatively thin wall thereof. If conventional thick brush block stock is used the tufted construction would be assembled according to the above identified, related patents. With attention to Figure 2, the bottle 100 defines a hollow interior 104. According to the process of my above patent, a heating means 105 is moved in the direction B toward the front surface 100'. The melting means is normally at a temperature of at least about 371°C (700 Fahrenheit) and this temperature is necessary in order to melt the surface 100' in about 1-2 seconds. As shown in figure 3, the melting means 105 causes a curvature 106 in surface 100', and after melting occurs the heating means 105 is translated backward in the direction C. While not shown, the heating means, if left adjacent to surface 100' a sufficient period of time, will not only melt the surface but open a hole there through, in addition to the distortion 106 shown in Figures 2-5. Immediately after briefly heating the front surface 100', a fused filament tuft end 108 is indexed in the direction D onto the heated portion 107 of the curved wall 106 as shown in Figure 4. After allowing for sufficient cooling, i.e. about 4-5 seconds, the fused filament tuft as shown in Fig. 5 is fused at point 109 to the wall section 106 of the bottle 100. As shown however there is distortion left at the point of fusion. If multiple filament tufts are fused simultaneously on the thin wall member either (1) the entire surface will warp out of plane thus distorting the brush face and causing a collapse of the bottle inward, or (2) due to an excess amount of heat applied during the fusion process the actual surface will melt away and there will be no solid wall portion to which the fused tufts may be attached. As shown then in Figs. 2-5, if my prior art patented process is used with a relatively thin walled hollow structural base it may be possible to fuse tufts thereto, but the resultant products will not meet specifications. In all likelihood the product will be a failure. With attention to Figs. 6-10, the modification of the instant invention can be seen for example in Figure 6 wherein the hollow bottle 200 has an open top 201 with threads 202 for accepting a closure or cap (not shown), front and back surface walls 200' and 200" respectively at a parting line 203 running around the side walls and the bottom of bottle 200 and the improvement wherein there are molded protrusions 204 radiating from the wall 200' and intended to accept tufts to form the brushware construction. It should be noted that the wall thickness for the hollow base member most desirably is in the range of 0.508 to 1.27mm (0.020 ― 0.050 inches) consistent with the instant invention. The improvement over the prior patented process described in the above of my patents is shown for example in Figs. 7-10 wherein the previously molded conical protrusion 204 of wall 200' is heated with heating means 205 whereby the heating means is indexed in the direction E towards protrusion 204, and after melting the same retracted in direction F away from melt 204' to leave a fused layer on a wall 200' where the protrusion 204 was originally molded. In this way a tuft 207 with a fused end can be indexed in the direction G onto the fused wall section 206. The fused wall section 206 is a mass of plastic occupying a small area of the wall 200'. The thickness is from about 0.508 to 1.016mm (0.02 ― 0.04") with a cross-sectional diameter of about 3.81mm (0.150"). The fused mass 206 extends outwardly from the surface of the wall a distance of about 2.54 to 3.81mm (0.1000 ― 0.150"). As the melter 205 (see Figure 7) is indexed forward in the direction E the extended portion 204 of the front side wall 200' of the hollow bottle 200 will melt when it comes into contact with the heater 205. As shown in Figure 8 this results in a melting portion of 204', and as it melts the melter means 205 is indexed away in the direction F. With reference to Figure 9, the melted portion 204' of Figure 8 becomes liquid to semi-liquid whereby the actual front surface 200' has not yet become melted or deformed. This then forms a mass of plastic 206 which is fluid sufficient to fuse a tuft thereon. Note in Figure 9, until the actual fusion takes place, there is a momentarily formed hollow section 204" behind the front wall 200". This melted mass 206 is still an integral portion of the original front wall 200'. As the melted fused filament tuft 207 of Figure 9 is indexed forward in the direction G towards the mass of plastic 206 it becomes fused at point 208 as shown in Figure 10. The tuft 207 is then integrally fused through the front surface 200' of the blow molded bottle 200 without heat distortion, open areas or other adverse features whereby the tuft 207 is integral with the bottle 200. As shown in Figure 6a, in the preferred embodiment of this invention there is provided a multiple grouping of molded extending protrusions 204 at a predetermined surface location 200' where fused brush tufts 207 will ultimately will be fused thereon. These multiple protrusions 204 can be of various cross-sectional shapes, thickness , diameters, and the like and can be designed to accept different size and length fused filament tufts. The protrusions 204, however, are formed by molding and preferably by blow molding. With attention to Figure 6b, there is not a visible distortion in the front wall surface 200' or on the inside surface wall portion 200''' after fusing. There is also provided no opening or openings in the outside wall from the internal hollow portion 204' after fusing. As shown at H, the wall thickness remains consistent throughout the front and back portions thereof 200' and 200", respectively. When blow molding is done with special methods, it is possible to maintain a consistent wall 200' in the front surface or tuft accepting area and at the same time thinning the back and side area of the bottle wall of thickness H to something less while still keeping the integrity of the overall bottle. As will be obvious to those skilled in the art, this invention is not intended to be limited to a wall of uniform thickness. The tuft accepting wall may be 1.016mm (0.040 inches) thick and the sides, bottom and back of the same bottle may have a thickness of only 0.508mm (0.020 inches). Figures 11 and 12 illustrate one embodiment of a completed hollow blow molded polypropylene liquid dispensing brush unit of the instant invention wherein the bottle 300 is hollow and has a threaded open top portion 301 and a multiplicity of fused polypropylene filament tufts 303 extending integrally from one front surface. A parting line is shown located at 302. When the actual fused unit 300 is filled with, for example, a hygienic liquid soap solution and a dispensing cap (not shown) attached, the bottle becomes a hand held soap dispensing hand and nail scrub brush as one integral unit for use to sanitize one's hands or other body areas. It is important that the ratio of the protrusion of the surface for accepting the fused filament tuft (see Figure 13) be at least 0.4. This ratio is calculated by the height, P, of the outer surface protrusion 400 outwardly from the surface, and the diameter, O, of the portion 401 at the base thereof. The wall thickness of the molded bottle must be in the range of 0.508 to 1.27mm (0.020" - 0.050") with height P at least twice the thickness of the surface from which it extends. The instant invention then is not limited to the above embodiments but variations from long, narrow handle type hollow units having fused filament constructions thereon to cleaning and dispensing chemical liquids or solid materials, to intricate 3-dimensional shapes are considered part of this invention. After reading the foregoing specification, one of ordinary skill will be able to effect various changes, substitutions or equivalents and various other aspects of the invention as broadly disclosed herein.

Claims: A method for fabricating a tufted construction by fusing synthetic filament tufts onto the outer surface (200') of a thin-walled synthetic hollow container (200,300), comprising: providing a thin-walled synthetic hollow container (200,300) molded to have an outer wall surface (200') and a plurality of mutually spaced protrusions (204) which are hollow projections extending outwardly in a predetermined pattern from said wall surface (200'); providing a plurality of parallel cut-to-length synthetic filament tufts (207,303), each tuft having a non-working end; providing a source of heat (205) and fusing the non-working ends of said tufts (207,303) and fusing said protrusions (204) of said container until said protrusions (204) collapse into molten plugs (206) at said wall surface (200'); and indexing the fused end of each tuft (207,303) into a fused protrusion (206) and allowing said fused tuft ends and protrusions to cool whereby said tufts (207,303) are integrally attached to said container (200,300) to form said tufted construction. The method of claim 1, wherein said container (200,300) is a blow molded container. The method of claim 1 or 2, wherein said tufts (207,303) and container (200,300) are made of the same synthetic material. The method of any one of claims 1 to 3, wherein said hollow container (200,300) has a wall (200') having a thickness of 0.508 to 1.27mm (0.020 to 0.050 inches). The method of any one of claims 1 to 4, wherein each protrusion (204), prior to fusing, has a ratio of height to width of at least 0.4. The method of any one of claims 1 to 5, wherein the height of each protrusion (204), prior to fusing, is at least twice the thickness of the surrounding container wall (200'). The method of any one of claims 1 to 6, wherein the diameter of each protrusion (204), prior to fusing, is about the thickness of each tuft (207,303).

Inventors: LEWIS JOHN C, LEWIS, JOHN C.
Applicants: TUCEL INDUSTRIES, TUCEL INDUSTRIES, INC.
Application year: 1997
Main classification: A46D3
IPC codes: A46B3, A46D3