SCOURING WEB

Background

The present invention relates to a scouring web. In particular, the present invention relates to a web comprising a metal fibers and abrasive particles secured to the web with an adhesive agent.

Metal wool pads, such as steel wool pads, have been used for a variety of household and industrial applications that require scouring or abrading a surface. Steel wool strands are used because a low cost scouring pad can be provided to consumers. One typical application for steel wool pads is in the household for scouring articles like pots and pans. The hardness of the metal and the sharp edges provide scouring action and polishes the metal surfaces of the pots and pans.

In spite of the practical applications, metal wool and in particular steel wool pads have a number of undesirable characteristics. The metal oxidizes and rusts, and metal wool pads have the tendency to shed metal fibers or splinters. The sharpness of the metal fibers makes the pad uncomfortable to hold. If contact is made with the metal wool pad, the splinters may enter the skin of the user and result in a metal sliver.

Non-woven fabric abrasive pads have also been used for cleaning and scouring. One such pad is commercially available under the trade name Scotch-Brite manufactured by 3M Company of St. Paul, MN. Typically, such an abrasive pad can be manufactured by a method disclosed in US Patent 2,958,593 (Hoover et al.). These non-woven pads are effective during cleaning for removing material such as food and stains from a surface. However, these pads are not as effective at polishing materials such as metal.

Summary

The disclosed scouring web is effective for scouring and polishing a surface during cleaning. In one embodiment, the scouring web comprises a plurality of metal fibers, an adhesive agent adhered to the fibers, and abrasive particles adhered to the web by the adhesive agent.

In one embodiment, the web further comprises a plurality of polymeric fibers blended with the metal fibers. In one embodiment, a portion of the polymeric fiber

secures the metal fibers and polymeric fibers together to form the web. In one embodiment, the polymeric fiber has a first portion having a first melting point and a second portion having a second melting point lower than the first melting point.

In one embodiment, the abrasive particles comprise soft large-sized particles with a diameter from 0.1 to 1 mm and a Mohs hardness from 2 to 4. In one embodiment, the abrasive particles comprise hard small-sized particles with a diameter from 1 to 10 μm and a Mohs hardness at least 8. In one embodiment, the abrasive particles comprise soft large-sized particles and hard small-sized particles. In one embodiment, a Mohs hardness of the adhesive agent is the same as the Mohs hardness of the soft large-sized particles. In one embodiment, the particle diameter of the soft large-sized particles is 10 to 1000 times the particle diameter of the hard small-sized particles.

In one embodiment, the scouring web further comprises a substrate attached to the web. In one embodiment, the web comprises a first side having soft large-sized particles and a second side opposite the first side having hard small-sized particles.

Brief Description of the Drawings

FIG. Ia is a perspective view of one embodiment of a scouring web;

FIG. Ib is an enlarged view of the scouring web of FIG. Ia;

FIG. 2 is a perspective view of the scouring web of FIG. Ia attached to a substrate.

While the above -identified drawings and figures set forth embodiments of the invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of this invention. The figures may not be drawn to scale.

Detailed Description

The scouring web comprises a plurality of metal fibers, an adhesive agent adhered to the fibers, and abrasive particles adhered to the web by the adhesive agent. In one embodiment, the scouring web only includes metal fibers. In such an embodiment,

the metal fibers may be made from a metal fiber tow or from processed chopped metal fibers. The metal fibers may from various types of metals or combinations of metals, described below. The adhesive agent adheres the particles to the web and may also provide strength to the web. The abrasive particles can be any type of abrasive particles. In one embodiment, the abrasive particles include soft large-sized particles, hard small- sized particles, or a combination there of, which is described below in more detail. A separate adhesive or additional processing may used to provide structural strength to the metal fiber web.

FIG. Ia is a perspective view of one embodiment of web 100, and FIG. Ib is an enlarged view of the scouring web 100 of FIG. Ia. In the embodiment shown in FIGS. Ia, Ib, 2, the web 100 comprises metal fibers 102 and polymeric fibers 104. Although the embodiment shown includes polymeric fibers, the polymeric fibers are optional.

As shown in this embodiment, the metal fibers 102 and polymeric fibers 104 are blended together so that the web 100 has a random distribution of the metal fibers and polymeric fibers 104. Typically, when blending metal fibers 102 with polymeric fibers 104, the web 100 includes at least 50% (wt.) of metal fibers 102. The web 100 may include at least 75% (wt.) metal fibers 102 or at least 85% (wt.) metal fibers 102.

The metal fibers 102 can include any type of metal fibers such as but not limited to steel, stainless steel, copper, brass, or bronze or blends of various metals. The metal fibers 102 are typically at least 0.5 inches (1.27 cm) long and have a thickness from 25 to 90 microns. In one embodiment, stainless steel is used because it is harder than other metal fibers like copper and bronze and is more corrosion resistant than steel wool.

In one embodiment, the polymeric fibers 104 include a portion that is capable of securing with the other fibers (metal or polymeric) to hold the fibers together and form the web. In such an embodiment, the polymeric fibers 104 may be a single component fiber or a multicomponent fiber. A single component fiber may be made from polypropylene. In such a case, the polymeric fiber may be heated to a point that the polymeric fiber begins to melt. The polymeric fiber then attaches to other fibers (polymeric or metal) and upon cooling, solidifies, and secures the fibers to form the web.

A multicomponent fiber is a fiber having at least two discrete portions. A multicomponent fiber is shown in FIG. Ib. One portion of the fiber 104 remains intact

and another portion of the fiber secures the polymeric fibers 104 and metal fibers 102 together to form a web. One type of multicomponent fiber is a core/sheath fiber and is shown in FIG. Ib. Reference will be made in the description to a core/sheath multicomponent fiber. However, it is understood that other types of multicomponent fibers are available.

In another embodiment, the polymeric fibers 104 and metal fibers 102 are blended and held together by an adhesive agent. That adhesive agent may be applied in any number of methods such as spray coating, roll coating, and can be applied in any number of patterns so that the entire web 100 is coated or only portions of the web 100 are coated. As will be described below, the adhesive agent may be used to secure the abrasive particles. Alternatively, a separate adhesive agent may be used to secure the abrasive particles.

Additional fibers may be included in the web 100. Other fibers include, but are not limited to staple fibers such as polyester and nylon, or ceramic fibers, carbon fibers, or natural fibers.

The polymeric fibers 104 shown in this embodiment include a core 106 and a sheath 108 covering at least a portion of the core 106 prior to processing. It is understood that the sheath 108, prior to processing, may cover the entire core or only a portion of the core. The core 106 may be comprised of such materials as polypropylene or polyester. The sheath 108 may be comprised of such materials as copolyester or polyethylene. The core 106 has a first melting point and the sheath 108 has a second melting point. The second melting point of the sheath is lower than the first melting point of the core. During processing, the sheath with the second melting point will melt, while the core remains intact. Then, the material of the sheath will resolidify to secure the web 100 together.

Typically, the polymeric fibers 104 are at least 1 inch (2.54 cm) long and have a denier of at least 2. Preferably, the polymeric fibers 104 are 1.5 inches (3.81 cm) long and have a denier of 12. One polymeric fiber 104 including a core and a sheath is Celbond® fibers 254, available from KoSa Co. of Wichita, Kansas where the sheath 108 has a melting point of HO ⁰ C.

Other multicomponent polymeric fibers may comprise a layered structure where one layer has a first melting point and another layer has a second melting point lower than the first melting point. In such an arrangement, the layer with the second melting point will melt and resolidify to secure the web together. Also, a polymeric fiber with a core and an adhesive surrounding at least a portion of the core, resulting in a fiber with tack, may be used as the polymeric fiber. In such a case, the adhesive exterior of the polymeric fiber secures the web together.

Under processing, the sheath 108 of the polymeric fibers 104 melts and upon cooling reforms in a solid state to secure with the metal fibers 102 and other polymeric fibers 104. During melting, the sheath 108 tends to collect at junction points where metal fibers 102 and polymeric fibers 104 intersect. Therefore, as shown in FIG. Ib, a portion of the polymeric fiber 104, and in this embodiment the sheath 108 secures the metal fibers 102 and polymeric fibers 104 to form the web 100.

A portion of the metal fiber 102 is covered with the reconfigured sheath 108 of the polymeric fibers 104. Therefore, these portions covered will be "soft" to the touch of the user so that overall the web has less piercing impact on the hand of a user as compared to a purely metal web. Additionally, the polymeric fibers 104 being distributed throughout the metal fibers 102 and randomly contacting and attaching the metal fibers 102 helps minimize portions of the metal fibers 102 from breaking free from the web 100. As can be seen in FIG. Ib, a single metal fiber 102 may have several contact points with the polymeric fiber 104 to assist with anchoring the metal fiber 102 to the web. Therefore, web 100 of the present invention sheds less metallic splinters as compared to a purely metal web.

By blending the metal fibers 102 with polymeric fibers 104, the overall need for metal fibers within the web is minimized. In other words, the polymeric fibers 104 dilute the metal fibers 102, and overall less metal fibers 102 are used in the web 100. Typically, stainless steel has been a preferred material because of its scouring and polishing ability and because it does not rust. However, stainless steel is relatively expensive compared to steel wool for example. The web 100 of the present invention allows for incorporation of stainless steel into a low cost web because the amount of metal (stainless steel) is diluted by the polymeric fibers.

An adhesive agent 200 is used for bonding abrasive particles 300 to the fibers of the web 100. This type of adhesive agent is often referred to as a make coat. As discussed above, the adhesive agent 200 may also be used to hold the fibers together, which is referred to as a size coat (whether or not a polymeric fiber having securing capabilities is used). In general, an adhesive agent 200 contains a binder resin and an additive as a component. A binder resin means an organic resin offering the function of bonding a substance by the change of a coatable liquid to a stiff solid. Also, an adhesive agent precursor particularly means an adhesive agent in a liquid state.

An adhesive agent used for bonding fibers of a non- woven fabric can be a thermosetting adhesive agent such as an aqueous suspension and an organic solvent solution of epoxy, melamine, phenol, urethane, isocyanate and isocyanurate resins, or a rubber-based polymer solution or suspension such as SBR, SBS and SIS. These adhesive agents are applied to fibers by an immersion coating method, a roll coating method, a spray coating method and the like so as to be thermoset.

In one embodiment, the abrasive particles 300 include a mixture of soft particles 310 and hard particles 320. Soft particles 310 have a Mohs hardness within a range of 1 to 7, preferably 2 to 4. A Mohs hardness of less than 1 in soft particles 310 brings an insufficient abrasive power to the web 100, while a Mohs hardness of more than 7 therein brings the possibility of scratching a surface to be polished. In one embodiment, the material of soft particles 310 is an inorganic material such as garnet, flint, silica, pumice stone and calcium carbonate, an organic polymer material such as melamine, polyester, polyvinyl chloride, methacrylate, methyl methacrylate, polycarbonate and polystyrene, and the like.

In one embodiment, soft particles 310 have a large size as compared with hard particles 320. For example, the particle diameter of soft large-sized particles 310 is 10 to 1000 times, preferably 30 to 100 times the particle diameter of hard small-sized particles 320. If the particle diameter of soft large-sized particles 310 is less than 10 times the particle diameter of hard small-sized particles 320, then the abrasive power of the web 100 may be rendered insufficient.

In one embodiment, the average particle diameter of soft large-sized particles 310 is 0.1 to 1 mm, preferably 0.1 to 0.3 mm. An average particle diameter of less than 0.1

mm in soft large-sized particles 310 brings difficulty in removing thick debris, such as scorching, while an average particle diameter of more than 1 mm therein brings difficulty in holding themselves properly.

In one embodiment, hard particles 320 have a Mohs hardness within a range of 8 or more, preferably 8 to 9. A Mohs hardness of less than 8 in hard particles 320 brings a weak function of removing hard and thin film- like debris. In one embodiment, the material of hard particles 320 is silicon carbide, aluminum oxide, topaz, fusion alumina- zirconia, boron nitride, tungsten carbide, silicon nitride and the like.

In one embodiment, the average particle diameter of hard small-sized particles 320 is 1 to 10 μm, preferably 2 to 7 μm. An average particle diameter of less than 1 μm in hard small-sized particles 320 typically is insufficient at removing hard and thin film- like debris, while an average particle diameter of more than 10 μm tends to scratch the surface.

When both soft large-sized particles 310 and the hard small-sized particles 320 are included, the ratio of the soft large-sized particles 310 and the hard small-sized particles 320 is useful in the range of from 1 :9 to 9: 1. If the soft large-sized particles 310 are larger in quantity than the range, it becomes difficult to remove hard and thin film- like debris, whereas if the hard small-sized particles 320 is larger in quantity than the range, it becomes difficult to remove soft and thick debris, such as food scorch. In one embodiment, a combination range is that the soft large-sized particles 310 are larger in quantity than a combination ratio of 2:8.

Both soft large-sized particles 310 and hard small-sized particles 320 are disclosed as one example of abrasive particles that may be used with the web 100. However, individually soft large-sized particles may be used or hard small-sized particles may be used. Also, it is understood that any other type, size, and hardness and various combinations thereof of particles 300 may be used with the web 100.

The adhesive agent 200 may be aqueous or solvent-based. In one embodiment, the adhesive agent after being thermoset preferably has substantially the same hardness as soft large-sized particles 310. If the hardness of an adhesive agent 200 is substantially lower than that of soft large-sized particles 310, then the adhesive agent 200 covers up the soft large-sized particles 310, and abrasive power becomes poor. If the hardness of an

adhesive agent 200 is substantially higher than that of soft large-sized particles 310, then a surface to be polished is possibly scratched.

In one embodiment, a binder resin of an adhesive agent 200 to be used can involve epoxy, melamine, phenol, isocyanate and isocyanurate resins, and the like. A particularly preferably binder resin is a phenol resin, an epoxy resin and the like.

The web 100 of the present invention may be used alone or in combination with various substrates. If used alone, further processing may be required to provide structural integrity to the web 100. The binder 200 resin provides structural integrity for the web 100 to be used without a substrate. The web 100 may be needlepunched, also known as needletacked, to provide structural integrity to the web 100. In addition, it is common to corrugate webs to help enhance the scouring ability of the web 100. The web 100 may be corrugated or have other three dimensional geometric patterns, such as circles, diamonds, rectangles, and squares.

The web 100 may include one type of abrasive particles on one side of the web 100 and a second type of abrasive particles on a second side of the web 100. For example, one embodiment may has one side of the web covered with soft large-particles and a second side of the web covered with hard small-particles. Alternatively, both (or all) sides of the web may be covered with the same types of particles or only a single side may be covered with particles.

FIG. 2 shows a scouring article 400, which comprises a scouring web 100 secured to a substrate 410. The scouring article 400 has at least one side of the web 100 (FIG. Ia and Ib) exposed for scouring. The overall construction of the scouring article 400 may be any combination of a web 100 attached to a substrate 410. Any known attachment mechanism may be used such as, but not limited to, needletacking, hydroentangling, or binding with adhesive. The binding layer may comprise an adhesive coating covering a portion of the substrate or the entire substrate. Also, the portion of the polymeric fiber 104 securing the web 100 together, if included, may extend to the substrate 410 to attach the web 100 to the substrate 410. The particular attachment mechanism will depend on the substrate 410 utilized, the concentration of polymeric fibers 104, and the end use application. Any one of these mechanisms or any combination of these mechanisms may be used to attach the web 100 to the substrate

410. The resulting scouring article 400 may be firm and relatively rigid or may be relatively flexible. On an embodiment of a scouring article 400, it is likely that only the working surface of the web 100 would include the abrasive particles.

In this embodiment, the substrate 410 is a sponge. However, the substrate 410 may be any known type of material such as foam, sponge, knitted, woven, nonwoven, paper, foamed polyurethane and other foamed synthetic and natural materials, other similar material. The substrate may be capable of absorbing fluid or itself may have scouring and/or polishing abilities. Optionally, the scouring article 400 may include a plurality of substrate layers.

The web 100, substrate 410 of the scouring article 400, or both may also be preloaded with detergent, soap, bleach, perfumes, colorants, antibacterial or antifungal chemicals or other known types of materials.

To scour a surface, a user may use the web 100 (FIG. Ia and FIG. Ib) or the scouring article 400 containing the web 100 (FIG. 2) to contact the surface to be scoured. The user may hold the web 100 or scouring article 400 or may attach it to a handled tool. The web may be used to scour or abrade any number of surfaces. Particularly, the web may be used to scour or abrade surfaces that are accommodating to steel wool pads or other such metal pads. Such surfaces include, but are not limited to metal and wood surfaces. One particular application of the web and scouring article includes scouring metal pots, pans, and other kitchenware. In such an instance, the web and scouring article scours and removes debris from the surface and polishes the metal. Preferably, the metal fibers included in the web will not rust. Use of the web 100 comprising metal fibers 102 along with the abrasive particle 300 provides a web 100 with superior properties in scouring and polishing.

The web 100 may be made in a variety of ways. US Patent Application 11/244,873, filed on October 6, 2005 titled "Scouring Web and Method of Making," the disclosure of which is herein incorporated by reference, discloses a method of making a metal/polymer fiber web. In one embodiment, to include the abrasive particles 300, the abrasive particles 300 are first added to an adhesive agent precursor and dispersed therein with sufficient uniformity so as to obtain a dispersion solution. The dispersion solution is applied on the surface of the fibers of the web. It is preferred that an applying

method to be used is an immersion coating method, a roll coating method, a spray coating method and the like.

In another embodiment, the particles 300 may be projected into the same adhesive agent precursor (if included) and concurrently applied, or projected into different adhesive agent precursors and separately applied. Also, an adhesive agent precursor may be first applied to the web, and then abrasive particles may be sprayed thereon.

In the case of using a thermosetting resin as a binder resin, the adhesive agent precursor is thereafter thermoset by heating for a certain time. In general, an adhesive agent precursor is thermoset by maintaining at a temperature of 100 to 300 ⁰ C for 10 to 30 minutes.

Although specific embodiments of this invention have been shown and described herein, it is understood that these embodiments are merely illustrative of the many possible specific arrangements that can be devised in application of the principles of the invention. Numerous and varied other arrangements can be devised in accordance with these principles by those of ordinary skill in the art without departing from the spirit and scope of the invention. Thus, the scope of the present invention should not be limited to the structures described in this application, but only by the structures described by the language of the claims and the equivalents of those structures.

Example Scouring Web

A. Scouring Web

The following fibers were blended in a 70:15:15 weight ratio (stainless steel fiber:bicomponent fϊber:polyester fiber). A 300 gsm (grams per square meter) lofty nonwoven web was prepared using an air lay machine available under the trade designation "RANDO WEBBER" from Rando Machine Corporation, Macedon, NY. The web was oven bonded at 300 ⁰ F (149 ⁰ C) to melt and bond the web.

• Type OO steel wool chopped to 3 inch lengths, from Global Materials Technologies of Palatine, IL

• Polyester/copoly ester bicomponent binder fiber, Celbond® Type 254, 12 denier, cut length 1.5 inches, from KoSa, Charlotte, NC

• Polyester fiber, 60 denier, from Wellman Inc. of Shrewsbury, NJ

B. Fiber Size Coat

Both sides of the web were spray coated with the below coating (total weight of 1.3g/200cm ² dry or 4.6g/200cm ² wet). The size coat was cured at 300 ⁰ F (149 ⁰ C) for 7 min.

• Water, 36.6% wt.

• Urethane resin, 60% wt., W895/494 from Incorez, USA

• Hardener, 2.4% wt., Carbodilite, SV-02 from Nisshimbo Industries of Japan

C. Make Coat

One side of the web was spray coated with the below coating (2.8g/200cm ² dry and 6.1 g/200cm ² wet). The make coat was cured at 300 ⁰ F (149 ⁰ C) for 7 minutes.

• Water 30% wt.

• Urethane resin 50% wt., W895/494 from Incorez, USA

• Silicone carbide, 5.5% wt., 8000 SiC from Fujimi Corp. of Tualatin, OR Mix the above in a high sheer mixer and add:

• Melamine mineral 12.7% wt. available from Media Blast

• Hardener, 2.0% wt., Carbodilite, SV-02 from Nisshimbo Industries of Japan