Method of making a tufted sponge

Abstract: A tufted sponge comprises filaments (308) of a tuft (310) which are fused to sponge material (300) via a cup-shaped mass (309") comprising the fused bases of the filaments (308). The side wall of the cup-shaped mass (309") contributes to the bonding to the sponge material (300) but does not restrict the flexing of the unfused portions (308) of the filaments of the tuft (310).

Description: The invention relates to a tufted sponge and a method of making a tufted sponge by providing a bond between tuft(s) and sponge material, of sufficient strength to keep the tuft(s) attached during vigorous use. The invention may be applied to fused spongeware scrub products that comprise only synthetic monofilament tufts attached to cellular sponge material. Many different methods for manufacturing scrub brushes have been devised in the past, including gluing, stapling and fusing tufts to a base. Even though, many years ago, a tufted sponge was patented, there has been no commercial acceptance of that product due to the fact that the fused end portion of the tuft could never be made to adhere to the sponge substrate during vigorous use. When the sponge was used, the fused tufts would readily fall away or pull out. US-3,641,610 discloses such a tufted sponge product and it is readily apparent that the fused filament mass which is used to attach each tuft to the sponge material is disc-shaped and is insufficient in surface area. Approximately only the bottom surface of each fused tuft is attached to sponge material and the sponge material merely pulls away from the fused tuft end during scrubbing. According to a first aspect of the present invention, there is provided a method of making a tufted sponge from open-celled sponge material and a tuft of synthetic fusible filaments, the method comprising: providing a sponge base made of the sponge material and having an opening in a surface thereof, the opening being formed by removal of a cylinder of the sponge material; providing a stockbox containing a supply of the filaments, wherein the filaments are arranged to be generally parallel; providing a hollow picking element which is substantially cylindrical and has an open first end; receiving a plurality of the filaments through the open end of the picking element to form the tuft with an end portion of the tuft extending from the open end of the picking element; heating said end portion of the tuft extending from the picking element until it consists entirely of fused filamentary material; using the picking element to insert the fused end of the tuft into the opening so that the fused filamentary material penetrates into the adjacent sponge material; permitting the fused filamentary material to cool; and withdrawing the picking element from the tuft so as to leave the tuft retained in the opening by interconnection between the fused filamentary material and the sponge material; characterised in that: said end portion of the tuft, prior to fusing, extends from the open end of the picking element by a distance greater than the diameter of the tuft; prior to insertion of the picking element, the opening in the sponge base is widened until it is a frusto-conical cavity; during insertion of the fused end of the tuft into the widened opening, the fused filamentary material forms a cup-like fused portion around the adjacent end of the picking element and the cup-like fused portion has a base and an annular side wall which penetrate into the adjacent sponge material; and after withdrawal of the picking element the unfused portions of the filaments of the tuft are left projecting away from the base of the cup-like fused portion without touching the annular side wall of the cup-like fused portion. Preferably, the height of the cup-like fused portion is at least equal to the diameter of the tuft. Preferably, the first end of the picking element is retained within the opening in the sponge base until the fused filamentary material has cooled. Preferably, the length of fused filamentary material extending from the picking element is at least 5 millimetres. Preferably, the diameter of the cylindrical opening is about the diameter of the picking element. Preferably, the method is performed a plurality of times using a plurality of the hollow picking elements to make a tufted sponge having a plurality of the tufts in respective openings in a common sponge base. The cup-like shape of the fused portion of the tuft provides a large surface area in contact with and bonded to the sponge material to thereby result in an attached fused tuft that will not fall away from the sponge base during scrubbing. According to a second aspect of the present invention, there is provided a tufted sponge comprising a sponge base of open-celled sponge material and a plurality of tufts of synthetic fusible filaments, wherein for each tuft: the tuft is secured in a respective opening in the sponge base by a cup-shaped mass of fused filamentary material comprising the fused bases of the filaments of the tuft; the unfused portions of the filaments of the tuft project upwards from the base of the cup-shaped mass without touching the annular side wall of the cup-shaped mass; and the base and annular side wall of the cup-shaped mass penetrate into the cells of the adjacent sponge material of the sponge base and lock the tuft to the sponge base. Preferably, for each tuft the annular side wall of the cup-shaped mass tapers towards the base of the cup-shaped mass. The term "sponge" substrate means any porous, wetable cellular type of material such as cellulose, polyurethane, polyolefins and the like. The term "synthetic" filament as used hereinafter includes filaments which are formed from linear thermoplastic polymers from the group consisting of polystyrene and polystyrene co-polymers, polyvinyl chloride and polyvinylchloride-acetate co-polymers, polyethylene, polypropylene, polyethylene-polypropylene co-polymers, polyamides, polyesters and polyurethane. Both oriented and unoriented filament may be employed. Also, various filament cross-sections may be imparted, such as, for instance, circular, lobular, trifoil, X, and Y cross-sections, triangular, polygonal, star, etc. Mixtures of synthetic filaments may be employed in cases where the compositions of the filaments are compatible during fusing operations. 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 biodegradable, or subject to decomposition during or after use. The term "picking" when used for multiple tufts refers to the formation of the tufts wherein two or more tufts are formed simultaneously by longitudinally engaging more than one cut-to-length filament at its ends and removing said filament from a parallel disposed bundle of filaments. Suitable picking devices are disclosed in U.S. Patent Nos. 3,471,202, 3,910,637, 4,009,910 and 4,109, 965 all issued to Lewis, among others. Non-limiting embodiments of the present invention will now be described with reference to the accompanying drawings, in which:- Fig. 1 is a part-sectional side view of a conventional synthetic filament fused tuft with base support; Fig. 1A is a cross-sectional view of the synthetic fused filament tuft of Fig. 1 taken along line 1A-1A; Fig. 2 is a part-sectional side view of a synthetic fused filament tuft with a cup-like base support, suitable for use in the method of the present invention; Fig. 2A is a cross-sectional view of the synthetic fused filament tuft of Fig. 2 as taken along line 2A-2A; Fig. 3 is a sectional view of a fused, conventional synthetic filament tuft in a cellulose sponge illustrating the base attachment area; Fig. 4 is a sectional view of a fused, cup-like synthetic filament tuft in a cellulose sponge illustrating the base attachment area of an embodiment produced by the method of the present invention; and Fig. 5 is a sectional side view of a cellulose sponge illustrating the sequence of steps of an embodiment of the method of the present invention. Referring to Figs. 1 and 1A, there is illustrated a conventional fused polypropylene filament tuft 100 having individual filaments 101 fused at their base 101' creating the support means 102 for holding or attaching said tuft to a portion of sponge. The filaments are first assembled, and their non-working ends 101' melted (fused) together thus forming the base 102. Figs. 2 and 2A illustrate an embodiment of a fused polypropylene filament tuft 200 of this invention having individual filaments 201 fused at their base creating the support 202 for holding or attaching said tuft to a portion of sponge. The filaments are first assembled, and their non-working ends melted (fused) together thus forming the base 202, in the same manner as the conventional formed tuft of Fig. 1. However, during the process of melting (fusing) additional filament material is melted thus creating a larger fused mass prior to affixing the fused portion to a substrate. When the molten mass of melted filament ends is inserted or affixed to a cellular substrate then there is created more than twice the surface area of the contact between the base and cellular material, thereby allowing for greater surface contact and lamination of the plastic filament melt 202 to the sponge. Fig. 3 illustrates the conventional fused tuft 100 as attached at the bottom of the fused portion 102 at 105 to a sponge 103. Thus the only tuft part affixed to the actual sponge material 103 is at 105. The space 104 along the radiating tuft filaments 101 extending from base portion 102 must be free to permit the tuft 101 to flex and move with the sponge material 103 during the cleaning and/or wiping process. Likewise, in Fig. 4 the improved fused tuft 200 is attached at the bottom and sides of the fused portion 202 to a sponge 203 according to this invention. Thus the additional fused portion 202 is affixed at the interface 205 to the actual sponge material 203. The space 204 along the radiating filaments 201 from base portion 202 leaves the tuft 200 free to flex and move with the sponge material 203 during the cleaning and/or wiping process as in the conventional fused tuft. However, there is a substantially greater bond between the filament base and the sponge. Figs. 1A and 2A illustrate the differences in the fused surface contacting the sponge. With reference to the conventional tuft 100 of Fig. 1A the melted non-working ends 101' of filament take the configuration of base 102 and the resultant area for attachment is the bottom surface area 102' having "x" diameter plus the area of the side of 102 having a height of "y". By giving "x" a diameter of 5 mm, the area of the bottom is 78.5 sq. mm. By giving "y" a height of 1 mm, the area of the perimeter becomes 31.4 sq. mm. Thus the total contact area is 109.9 sq. mm. Comparing the melted non-working ends 201' of filament 201 of Fig. 2A the configuration of base 202 and the resultant area for attachment is calculated to be the bottom surface area 202' having "x" diameter plus the area of the side of 202 having a height of "z". By giving "x" a diameter of 5 mm, the area of base section 202' becomes 78.5 sq. mm. By giving "z" a height of 5 mm, the area of the perimeter becomes 157 sq. mm. Thus there is a total contact area of 235.5 sq. mm to be attached to the material. An embodiment of the method of the present invention is illustrated in Fig. 5 and is described below. First, a center line 302 in the sponge material 300 is identified for the opening located at the dotted section 301. Next, actual sponge material is removed as illustrated at 303, thus creating an opening with sides 303' and bottom section 303". The diameter of the bottom 303" should be no larger than the outside diameter of the filament picking means 306. After the hole area 303 is created, a preconfigured means 304 having capabilities of further opening the hole area 303, but not removing sponge material 300, is inserted into the opening 303 to force the walls 303' of the opening 303 further apart to create a tapered (frusto-conical) configuration 305' for the acceptance of the melted filament material during the insertion of the fused filament 308. After the hole section 305 has been expanded, the premelted filament 308 with fused portion 309 and a movable working end trim means 307, in picking means 306, is inserted in direction "C" into opening 305. Picking means 306 continues to index until the fused mass 309 comes into contact with the side walls 305' and bottom 305". The fused filament mass 309 penetrates into open celled sponge surface 305' and then cools and solidifies in a few seconds, i.e. 3-4 seconds, and becomes attached to the sponge material 300 at the interface 309'. The picking means 306 is then indexed out of the opening 305 in direction "D". Within a short period of time the sponge 300 returns to its original attitude and creates a space 311 between the filaments 308 of tuft 310 and the sponge 300. When comparing the fused tuft 100 of Fig. 3 to the fused tuft 310 of Fig. 5, it is apparent that the resultant tuft of the present invention is superior in its ability to withstand the flexing and scrubbing action, and much more resistant to removal. This is because of the creation of the "cup-like" fused tuft section 309" formed by allowing for the melted mass of filament attached to the wall portion of the sponge to be much larger. It should be noted also that section 309" adheres to the interface of the hole 305 and climbs the sides 305', leaving a space 311 between the tuft 310 and the section 309". This permits the tuft to flex during scrubbing action. To reiterate, in the prior art embodiment of Fig. 3, the fused tuft end 102 is essentially a flat dish or plate. Before it cools, it only penetrates the adjacent open-celled sponge material. In contrast, as shown in Fig. 5, when the picking element 306 indexes in the direction "C" the fused end 309 forms a cup-shape around the end of the picking element as it penetrates the adjacent sponge material. When the fused end cools and the picking element indexes in the direction "D", the cup-shaped base section 309" will provide a much greater bonded surface with the adjacent sponge material, while leaving the open area 311 surrounding the tuft, so that flexibility of the tuft 310 will not be lessened. Instantaneously picking and fusing all the filament tufts in one plane and in parallel filament arrangements into a sponge base may be used when practicing the instant invention.

Claims: A method of making a tufted sponge from open-celled sponge material, 300 and a tuft of synthetic fusible filaments, the method comprising: providing a sponge base made of the sponge material 300 and having an opening 303 in a surface thereof, the opening being formed by removal of a cylinder of the sponge material; providing a stockbox containing a supply of the filaments 308, wherein the filaments are arranged to be generally parallel; providing a hollow picking element 306 which is substantially cylindrical and has an open first end; receiving a plurality of the filaments 308 through the open end of the picking element 306 to form the tuft with an end portion of the tuft extending from the open end of the picking element; heating said end portion of the tuft extending from the picking element until it consists entirely of fused filamentary material 309; using the picking element to insert the fused end of the tuft into the opening 303 so that the fused filamentary material 309 penetrates into the adjacent sponge material 300; permitting the fused filamentary material to cool; and withdrawing the picking element from the tuft so as to leave the tuft retained in the opening by interconnection between the fused filamentary material and the sponge material; characterised in that: said end portion of the tuft, prior to fusing, extends from the open end of the picking element by a distance greater than the diameter of the tuft; prior to insertion of the picking element, the opening in the sponge base is widened until it is a frusto-conical cavity 305'; during insertion of the fused end of the tuft into the widened opening, the fused filamentary material forms a cup-like fused portion 309" around the adjacent end of the picking element and the cup-like fused portion has a base and an annular side wall which penetrate into the adjacent sponge material; and after withdrawal of the picking element the unfused portions of the filaments of the tuft are left projecting away from the base of the cup-like fused portion without touching the annular side wall of the cup-like fused portion 309". The method of claim 1, wherein the height of the cup-like fused portion is at least equal to the diameter of the tuft. The method of claim 1 or 2, wherein the first end of the picking element is retained within the opening in the sponge base until the fused filamentary material has cooled. The method of any one of claims 1 to 3, wherein the working end of the tuft stands slightly proud of the surface of the sponge base. The method of any one of claims 1 to 4, wherein the length of fused filamentary material extending from the picking element is at least 5 millimetres. The method of any one of claims 1 to 5, wherein the diameter of the cylindrical opening is about the diameter of the picking element. The method of any one of claims 1 to 6, wherein the method is performed a plurality of times using a plurality of the hollow picking elements to make a tufted sponge having a plurality of the tufts in respective openings in a common sponge base. A tufted sponge comprising a sponge base of open-celled sponge material and a plurality of tufts of synthetic fusible filaments 200, wherein for each tuft: the tuft 200 is secured in a respective opening in the sponge base by a cup-shaped mass of fused filamentary material comprising the fused bases of the filaments of the tuft; the unfused portions of the filaments of the tuft project upwards from the base of the cup-shaped mass without touching the annular side wall of the cup-shaped mass; and the base and annular side wall of the cup-shaped mass penetrate into the cells of the adjacent sponge material of the sponge base and lock the tuft to the sponge base. A tufted sponge according to claim 8, wherein for each tuft the annular side wall of the cup-shaped mass tapers towards the base of the cup-shaped mass.

Inventors: LEWIS JOHN C, LEWIS, JOHN C.
Applicants: TUCEL INDUSTRIES, TUCEL INDUSTRIES, INC.
Application year: 1996
Main classification: A46B3
IPC codes: A46B3, A47L13