WO2008048868A2

WO2008048868A2 - Pool cover fabric containing algaecide and/or bactericide to reduce algae/bacteria growth

Info

Publication number: WO2008048868A2
Application number: PCT/US2007/081176
Authority: WO
Inventors: Ralph Alan Sutton; Noah Nichols
Original assignee: Propex, Inc.
Priority date: 2006-10-13
Filing date: 2007-10-12
Publication date: 2008-04-24
Also published as: WO2008048868A3; US20080086808A1

Abstract

A woven fabric pool cover has an antimicrobial agent that reduces/prevents the growth of microbes on the pool cover and in the water of a swimming pool covered by the cover. The fabric cover may be woven from polyolefin extruded monofilaments, and/or fibrillated tape yarns where the yarns have an antimicrobial agent added during the yarn extrusion process or added to fabric formed by the yarns. The fabric may be woven from traditional polyolefin extruded monofilaments, and/or fibrillated tape yarns before the resulting fabric is treated with a antimicrobial agent. Such treatment may involve spraying a solution onto the fabric or also dipping, soaking, or padding the fabric into the treating solution. The antimicrobial agent may form a zone of inhibition around the yarns and may seep out of the fabric to form zones of inhibition in the surrounding environment, like on the cover and/or in swimming pool water.

Description

POOL COVER FABRIC CONTAINING ALGAECIDE AND/OR BACTERICIDE TO REDUCE ALGAE/BACTERIA GROWTH

CROSS REFERENCE TO RELATED APPLICATION FOR WHICH A BENEFIT IS CLAIMED UNDER 35 U.S.C. §119(e)

This patent application claims priority under 35 U.S.C. §119(e) to United

States Provisional Patent Application No. 60/829,375, entitled "Pool Cover Fabric

Containing Algaecide and/or Bactericide to Reduce Algae/Bacteria Growth," filed

October 13, 2006. The complete disclosure of the above-identified priority application is hereby fully incorporated herein by reference.

FIELD OF THE INVENTION

Broadly, this invention relates to swimming pool covers. More specifically, the present invention relates to manufacturing a woven pool covering fabric with an additive. The fabric may allow light transmission but the additive can reduce or eliminate microorganism growth, such as bacteria and algae, on the pool covering and in a swimming pool while the pool is covered.

BACKGROUND Swimming pool covers are generally installed over swimming pools to protect the swimming pools from leaves and other debris that would otherwise accumulate in the pool when the pool is not in use. For example, a swimming pool may be out of use when the climate is too cold for swimming. Furthermore, a pool cover may prevent a person from inadvertently falling into the pool, thus preventing drowning or hypothermia from exposure to winter cold water.

Pool covers are generally either permeable, or impermeable. For example, some pool covers are impermeable vinyl sheets, which allow little or no light, air, or water to pass through the cover. While such covers can provide a physical barrier to debris entering the pool, they are generally quite heavy. For example, they may weigh as much as 12 to 14 ounces per square yard. Such weight can make the covers difficult to manipulate and store. Additionally, the solid material may increase the cost of manufacturing and delivering the pool cover. In contrast to solid, vinyl pool covers, permeable pool covers may allow light, air, and/or water to pass through the pool cover. Unfortunately, light from the sun shining through the pool cover may allow, or encourage, the growth of microbes, such as algae, in the pool water. Such algae growth must be removed from the pool to render the pool water safe for humans. Algae removal is generally time consuming and expensive since the pool must be chemically treated and physically cleaned to kill and remove the algae.

One example of a permeable pool cover is a woven fabric pool cover. Such a woven fabric cover may be considerably lighter, easier to handle, and less expensive than a solid vinyl cover, however the woven nature of the pool cover may allow light to pass and encourage algae growth. Accordingly, there is a need in the art for a pool cover fabric of light construction (such as a woven fabric) that will prevent, or reduce, algae growth when used to cover a swimming pool.

SUMMARY OF THE INVENTION

The present invention relates to a woven fabric pool cover comprising an antimicrobial agent such as an algaecide and/or bactericide. Such a fabric can have reduced weight and may still prevent, or reduce, algae growth and bacteria on the pool cover and in a swimming pool that is covered by the fabric. This may reduce the amount of chemicals that are typically added to the pool before covering, or used to clean the pool after uncovering. The woven structure of the cover may reduce the weight of the cover and also may reduce costs associated with the manufacture, material components, or transportation of the cover. Furthermore, the lighter woven cover may provide increased ease of use thus improving compliance with suggested use patterns further increasing efficacy of the cover.

The fabric cover may be woven from polyolefm extruded monofilaments, and/or fibrillated tape yarns where the yarns have an algaecide and/or bactericide added during the yarn extrusion process. Alternatively, the fabric covers may be woven from traditional polyolefm extruded monofilaments, and/or fibrillated tape yarns before the resulting fabric is treated, as a whole, with an algaecide and/or bactericide. Such treatment may involve spraying a solution onto the fabric or also dipping, soaking, or padding the fabric into the treating solution.

The antimicrobial agent provided within the woven fabric pool cover may slowly seep out of the fabric or leach into the swimming pool water or other surrounding environment when the pool cover comes into contact with water, such as rain, snow, or water from other sources. Such seeping or leaching of the antimicrobial agent may expand the effectiveness of the additive algaecide and/or bactericide associated with the woven fabric pool cover and create a zone of microbe growth inhibition. The discussion of woven fabric pool covers in this summary is for illustrative purposes only. Various aspects of the present invention may be more clearly understood and appreciated from a review of the following detailed description of the disclosed embodiments and by reference to the drawings and the claims that follow. Moreover, other aspects, systems, methods, features, advantages, and objects of the present invention will become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such aspects, systems, methods, features, advantages, and objects are included within this description, are within the scope of the present invention, and are protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates a swimming pool and permeable pool cover characteristic of the prior art.

Figure 2 illustrates a top view of a Petri dish with a zone of microbe growth inhibition around a treated yarn according to one exemplary embodiment of the present invention.

Figure 3 illustrates an enlarged perspective view of a portion of a pool cover woven of chemically treated yarns, including round yarns, according to one exemplary embodiment of the present invention. Figure 4 illustrates an enlarged perspective view of a portion of a pool cover woven of chemically treated yarns, including fϊbrillated tape yarns, according to one exemplary embodiment of the present invention.

Figure 5 is a logic flow diagram of a process for manufacturing pool covers containing algaecide and/or bactericide according to one exemplary embodiment of the present invention.

Figure 6 is a logic flow diagram of a process for manufacturing pool covers with a surface treatment of algaecide and/or bactericide according to one exemplary embodiment of the present invention. Many aspects of the invention will be better understood with reference to the above drawings. The elements and features shown in the drawings are not to scale, emphasis instead being placed upon clearly illustrating the principles of exemplary embodiments of the present invention. Moreover, certain dimensions may be exaggerated to help visually convey such principles. In the drawings, reference numerals designate like or corresponding, but not necessarily identical, elements throughout the several views.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The present invention relates to a woven mesh pool cover incorporating an additive, such as an antimicrobial, an algaecide, or a bactericide, that may reduce, or prevent, the growth of algae, fungus, bacteria, or other microbes on the pool cover and/or in a swimming pool. Example yarns that can be used in weaving the cover can be in a denier range from 100 to 5000 and can be, for example, monofilament, fibrillated tape, multifilament, or otherwise. The algaecide and/or bactericide chemicals may be added to the yarns when the yarns are extruded.

Alternatively, the algaecide and/or bactericide chemicals may be applied to the fabric, as a whole, after the fabric is woven.

The invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those having ordinary skill in the art. Furthermore, all "examples" or "exemplary embodiments" given herein are intended to be non-limiting, and among others supported by representations of the present invention.

Turning now to Figure 1, the figure illustrates a swimming pool 100 and permeable pool cover 110 characteristic of the prior art. Traditionally, permeable pool covers 110 allow light, sunlight 120 for example, to pass through the cover 110 and into the swimming pool 100. While permeable pool covers 110, such as those constructed of woven fabrics, may be lighter and less costly than solid, non- permeable pool covers (not illustrated), the passing of sunlight 120 into the pool water 130 may promote the growth of algae 140 within the swimming pool 100.

In contrast to Figure 1, the remaining figures relate to exemplary embodiments of the present invention wherein woven fabric pool covers may benefit from lighter construction than solid pool covers, yet reduce, or prevent, the growth of algae 140 within the swimming pool 100 through the incorporation of an antimicrobial agent, such as an additive containing algaecide and/or bactericide chemicals within, or upon, the fabric of the woven pool cover.

Turning now to Figure 2, the figure illustrates a top view of a Petri dish 200 with a zone of microbe growth inhibition 230 around a treated fiber 210 according to one exemplary embodiment of the present invention. A treated fiber 210 may be placed within a Petri dish 200 that has been inoculated with one or more microbes 220. Examples of the microbes 220 may be algae, fungus, bacteria, other microbes, or any combination thereof. A zone of inhibition 230 around the sample of fiber 210 can illustrate the efficacy of the chemical treatment that has been incorporated into, or on, the yarn 210 to inhibit the growth of the microbe 220 under test. The zone of inhibition 230 may represent, on a small scale, the environment

(such as water or air) surrounding the treated fiber 210 that may be influenced by the chemicals in, or on, the fiber 210. The surrounding environment may be influenced by the chemicals if the chemicals can leave the fiber 210 to combine with the environment, or water in the surrounding environment. Such a surrounding environment may include, for example, the water of a swimming pool where a cover over the swimming pool has been woven of treated fibers 210. Other surrounding environments may be applicable, such as framing, trusses, insulation, and wallboard in an exemplary house wrap application where the house wrap can comprise treated fibers 210. Another example environment may be the surrounding ground material in an exemplary geotextile application where the geotextile may comprise treated fibers 210.

Turning now to Figure 3, the figure illustrates an enlarged perspective view of a portion of a pool cover 300 woven of chemically treated yarns, including round yarns 320, and flat yarns 310 according to one exemplary embodiment of the present invention. The yarns 310, 320 woven into the pool cover 300 can be treated with an antimicrobial agent 330 that is water soluble. However, the invention is not limited water soluble antimicrobial agents and may include hydrophobic antimicrobial agents.

The antimicrobial agent 330 can include algaecide, bactericide, or some combination thereof. The antimicrobial agent 330 may be added to the yarns 310, 320 while the yarns 310, 320 are being extruded, or the antimicrobial agent 330 may be applied to the entire fabric 300 after weaving. The entire pool cover may be 36 feet by 18 feet, 34 feet by 20 feet, or any other example dimension as may be determined by the fabrication of woven material and depending upon exemplary applications. In addition to pool covers, the woven fabric comprising an antimicrobial, such as an algaecide and/or bactericide, may be used in association with various other fabric applications and their associated yarns and fibers. Such applications may be, for example, in the geosynthetic, flooring, concrete, furnishing, or industrial markets.

For example, geosynthetic fabrics may include storm water applications, woven geotextiles, non-woven geotextiles, paving applications, silt fencing, or Earth control blankets. Also, flooring fabrics may include primary carpet backing, secondary carpet backing, construction applications, or various underlayments. Fabrics, yarns, and fibers associated with concrete applications may include reinforcing fibers, curing blankets, or underlayments. Furnishing fabric applications may include furniture materials, bedding, automotive, or construction applications such as roof underlayments, building wraps, or otherwise. Various industrial fabric applications may include pool covers, tents, flags, window coverings, awnings, trampolines, filtration components, agricultural applications, structural applications, and various others where the antimicrobial fabric may be useful for the prevention, or reduction, of the growth of microbes, such as algae and bacteria. In swimming pool cover applications, the pool cover 300 may be woven using a 525 F denier flat warp yarn 310. Denier is a unit of measure for the linear mass density of fibers and is defined as the mass in grams per 9,000 meters of fiber. An F denier indicates a Filament denier in contrast to a Total denier. Filament denier relates to a single filament of fiber (also known as Denier per Filament or D. P. F) while Total denier relates to an agglomeration of filaments. Such a yarn 310 may, for example, be 0.006 inches (0.152 mm) thick and 0.020 inches (0.508 mm). The filling yarn 320 may also be called the weft yarn 320. The filling yarn 320 may, for example, be a 565 denier round yarn or monofilament yarn.

The woven mesh pool cover 300 can incorporate the antimicrobial agent 330 into the thermoplastic yarns 310, 320 during the extrusion process where the yarns are formed. The added antimicrobial agent 330 may reduce, or prevent, the growth of algae, fungus, bacteria, or microbes in a swimming pool. One example of an antimicrobial agent 330 that can be used is the Ciba IRGAGUARD B 1000 + F 3000 additive. Other example antimicrobial agents include Ciba IRGAGUARD B 5000, Ciba IRGAGUARD B 7000, Duraban brand antimicrobial agents, Duralast brand antimicrobial agents, or other silver-based anti-microbial agents for improved ultraviolet performance. The antimicrobial agent 330 may comprise one chemical or a plurality of chemicals.

Other example yarns 310, 320 may be in a denier range from 100 to 5000. These yarns can also be monofilament, fibrillated tape, or multifilament, as examples. Air flow of the material can range from 5 to 750 CFM. Example warp construction (in ends per inch) can range from 10 to 50. Example fill construction (in picks per inch) can range from 5 to 40. The woven cover 300 may provide more than 95% shade properties to reduce the algae growth in their pool while it is covered over the winter. Various thermoplastic yarns 310, 320 can be woven to form the pool cover 300. For example, the yarns can be polyolefϊn, polypropylene, polyamide, polyethylene, polyester, copolymer, nylon, etc. Polypropylene may be the primary plastic used to extrude, weave and carry the antimicrobial agent 330 to reduce algae and fungi growth on the cover. These yarns can be monofilament, tape, fibrillated tape, or multifilament depending on how the fiber is extruded.

Turning now to Figure 4, the figure illustrates an enlarged perspective view of a portion of a pool cover 400 woven of chemically treated yarns 410, 420, including fibrillated tape yarns 420, according to one exemplary embodiment of the present invention. The cover 400 is of a plain weave construction and employs flat monofilament warp yarns 410 and fibrillated tape filling yarns 420. Filling yarns 420 may also be referred to as weft yarns 420. Both yarns 410, 420 may be manufactured from a thermoplastic polymer comprising polyolefms selected from the group of polypropylene, polyethylene, polybutylene, and the like. A preferred polyolefm is polypropylene. Other thermoplastic polymers can also be employed such as the polyamides (nylons) and polyesters. The pool cover 400 provides for a woven fabric that may offer shade properties similar to a solid vinyl product while being significantly lighter and allowing air and water to pass through the pool cover 400. The warp yarns 410 may have a denier ranging from about 100 to about

2000, with about 525 F denier being preferred. The warp yarns 410 can be about 0.004 to 0.009 inches (0.102 to 0.229 mm) thick and about 0.017 to 0.023 inches (0.431 to 0.584 mm) wide, with 0.006 inches (0.152 mm) thick and 0.020 inches (0.508 mm) wide being preferred. The fibrillated fill yarn 420 can have a denier range from about 500 to 5000, with 3000 being preferred. The fibrillated fill yarn 420 may be beaten into the fabric as much as the loom will allow, thus substantially closing the openings in the fabric. The fabric 400 may also be calendared to a specified air flow to obtain desired drainage and shade properties.

The end count of the woven fabric forming the pool cover 400 may be measured as AA by BB, meaning AA warp yarns per inch in the machine direction and BB weft yarns in the cross-machine direction. The warp yarn end count may be from about 33 to about 42 per inch, with about 37 to 39 ends per inch being preferred and 38 being most preferred. Similarly, the weft or fill yarn end count may be from about 10 to about 20 ends per inch, with about 12 to 15 ends per inch being preferred and 13 being most preferred. Generally, the pool cover fabric 400 can have a weight of about 4.0 to about

10.0 ounces per square yard, with about 8.5 ounces per square yard being preferred. Air flow of the pool cover fabric 400 may be from about 20 CFM (566 liters/minute) to about 500 CFM (14,150 liters/minute) with about 25 CFM (708 liters/minute) to about 40 CFM (1132 liters/minute) being preferred, and about 25 CFM (708 liters/minute) being most preferred.

In addition to the antimicrobial agent 330 added to pool cover 400, the incorporation of fibrillated tape yarns 420 may combine the best qualities of a woven mesh fabric and a solid vinyl fabric. The construction of pool cover 400 may provide adequate shade to slow algae growth in the pool while also providing drainage and a lighter weight construction.

Turning now to Figure 5, the figure shows a logic flow diagram of a process 500 for manufacturing pool covers containing an antimicrobial agent 330 according to one exemplary embodiment of the present invention. Certain steps in the processes or process flow described in the logic flow diagram referred to hereinafter naturally precede others for the invention to function as described. However, the invention is not limited to the order of the steps described if such order or sequence does not alter the functionality of the invention. That is, it is recognized that some steps may be performed before, after, or in parallel with other steps without departing from the scope or spirit of the invention. In Step 510, a thermoplastic material is provided. The exemplary thermoplastic can be received in either powder or pellet form to be processed into a yarn. The powder or pellet may be either vacuum loaded or gravity fed into an extruder. Example thermo plastics may include polyolefms selected from the group consisting of polypropylene, polyethylene, polybutylene, and other similar thermoplastic materials. Other thermoplastic polymers may also be employed such as the polyamides (nylons), polyesters, or otherwise. These materials may also be used in any combinations or as copolymers.

In Step 520, the antimicrobial agent 330 is applied in the extrusion process. One example of the antimicrobial agents that can be used is Ciba IRGAGUARD B 1000 + F 3000. Other example antimicrobial agents include Ciba IRGAGUARD B 5000, Ciba IRGAGUARD B 7000, Duraban brand antimicrobial agents, Duralast brand antimicrobial agents, or other silver-based anti-microbial agents for improved ultraviolet performance. The antimicrobial agent 330 may be provided as a concentrate to the extrusion process. For example, the concentrate may be 10% B 1000, 10% B 5000, 10% Ultraviolet Stabilizer, and 70% carrier thermoplastic, by weight.

In one exemplary embodiment, the chemical agent can be added into the thermoplastic in a percentage, by final weight, of between 0.1% and 2.0% depending on the fungi/algae growth to be prevented. Typical values may be in range of 0.5% to 1.0% of final weight, as examples.

Antimicrobial agents 330 can be fed to the extruder in solid or powder form or they can be added as a liquid. The powder or pellet form can be added in a similar manner as the virgin plastic provided in Step 520. That is, by utilizing a feed system to let each additive into the extruder along with the virgin plastic at a specified percentage. A solid antimicrobial agent 330 may blend in with the virgin plastic as the plastic becomes liquid through the application of heat and pressure. A liquid additive can be added to the virgin plastic while it is in liquid form either in the extruder barrel or a downstream throat or die.

The heat in the barrel zones of the extruder as well as the heat of the die can be set depending on the thermoplastic being extruded. Nylon can have a higher melting point than polypropylene so the barrel zones and die may need to be set at a higher temperature. The antimicrobial agent 330 can be added into the pool cover product as a solid pellet compounded with a carrier resin. Since a pool cover is used outdoors a UV stabilization package (up to 2% of the final fabric) can also be added during extrusion. In Step 530, the thermoplastic material is extruded into yarn. The thermoplastic material provided in Step 510 and the chemical additives provided in Step 520 are coextruded to form chemically treated yarn in Step 530. The extruder can include a screw inside of a barrel that forces the thermoplastic through the barrel while heat and pressure are being applied. This may transform the thermoplastic from solid to liquid form. The molten thermoplastic can then forced through a die to give it the desired shape. Dies for slit tape and fϊbrillated tape yarns may be rectangular in shape and the individual ends may slit out of the sheet after the plastic has been transformed from a liquid back to a solid. Monofilament and multifilament yarns can be extruded through individual die holes prior to be transformed back to a solid.

After the thermoplastic goes through the die, it may be quenched or turned back to a solid by either running it through water or exposing it to cool air. After the plastic fiber is turned to a solid from, it can be drawn or oriented to give strength. This may be accomplished by running the fiber through a roller or series of rollers in which the subsequent set of rollers is turning at some predetermined speed that is faster than the previous set. An example of this is a 6:1 draw ratio where the first set of rollers is turning at 100 ft/min and the next set of rollers would be tuning at 600 ft/min. The fiber can be exposed to heat during this drawing/orienting process to soften it while it is being oriented. The heat can be applied through hot water, hot air in an oven, heated rollers, etc. The fiber can now be annealed to remove shrinkage by relaxing the yarn back under heat or it can be wound onto a tube or spool to go to the beaming or weaving process.

In Step 540, the yarn that was extruded in Step 530 is woven into a fabric. Extruded yarn can go to either the beaming or weaving process after being wound onto a spool or tube. The yarn that is utilized in the warp direction can go to a warper or beamer before being placed on the loom. This does not have to be the case as the warp packages can be put into the weaving machine directly from a creel. In either case, specific instructions can be given that detail a pattern of ends and specific ends per inch to be placed on the warp or in the creel. This can determine the pattern as well as coverage the warp direction yarns will provide. The warp direction can also be referred to as the machine direction. After the warp ends are beamed or placed in the creel, the ends can be drawn through a series of heddles prescribed to give the required weave pattern. The heddles can move up and down in a pattern communicated by an electronic board or card readout. This up and down movement along with the filling yarn firing across the loom at each crossing of the heddles can determine the weave pattern. This can serve as what bonds or weaves the fabric together. A pick gear or programmed electronic mechanism can determine the number of picks per inch to be placed in the fabric. This pick level can also determine the coverage the fabric will have from the filling yarn.

In Step 550, one or more fabric finishing steps may be applied to the fabric that was woven in Step 540. Once the fabric is woven, the fabric roll can be processed through one or more finishing step or the fabric can be shipped out as is. The woven pool cover fabric may be calendared after weaving. Some woven pool cover fabrics may be tentered as well in order to remove residual shrinkage in the plastic or maintain a width tolerance on the fabric. The calendar can be used to crush the fabric to a specific air flow or thickness through a combination of heat and pressure. The calendar can consist of two heated steel rollers. One of the rollers can be situated above and the second below a fiber roll that can be made of many different materials. The fabric can be threaded between the steel rolls and the fiber roll to subject it to heat and the upward and downward pressure of the steel rolls. The pressure may be controlled by hydraulics.

In Step 560, the fabric that was woven in Step 540 and finished in Step 550 can be formed into a cover, such as pool covers 300, 400. The fabric can be cut into the length and shape needed to cover a swimming pool. Since the woven good may not be wider than 73 inches in some exemplary embodiments, three or more pieces can be connected to cover the width of the pool. The pieces can be sewn together. A woven nylon strap can be attached at the seam and also periodically across the cover, every three feet for example. These straps can be sewn to the fabric in both the width and length direction. This nylon strapping can be approximately one inch wide and can be woven using an ultraviolet (UV) stabilized multifilament yarn. The nylon strapping can extend past the edge of the cover from 12 inches to 24 inches. This nylon length can be attached to a hook or apparatus that can slide over a peg to stretch the cover taunt and suspend it above the water surface.

In Step 570, the cover that was fabricated in Step 560 can be applied to a swimming pool by an installer or end user in the field. The woven cover can be suspended above the water level of a pool. The height above the water level can vary depending on the water level when the cover is installed and the amount of rain during the period of time the cover is installed. The cover can extend past the edge of the pool for approximately six to twelve inches around the entire circumference of the pool. As a performance example, a pool cover may remain on a pool from seven to nine months (or more) depending on the climate where the pool is located.

In Step 580, the cover that was applied to the swimming pool in Step 570 can be exposed to environmental water. In addition to the water in the swimming pool, environmental water may include rain, snow, water from other sources, or any combination thereof.

In Step 590, the antimicrobial agent 330 within the cover can form a zone of inhibition within the environmental water, such as in the water of the swimming pool. The incorporation of antimicrobial agent 330 may substantially stop algae, bacteria, fungi and/or other microbes from growing on the cover while it is installed or stored. Furthermore this benefit may extent into the surrounding environment and environmental water, such as the water in the swimming pool. The antimicrobial agent 330 may also prevent the growth of algae, bacteria, fungi and/or other microbes from items contaminated and falling on the surface of the cover. Turning now to Figure 6, the figure shows a logical flow diagram of a process 600 for manufacturing pool covers with a surface treatment of antimicrobial agent 330, such as an algaecide and a bactericide, according to one exemplary embodiment of the present invention. Certain steps in the processes or process flow described in the logic flow diagram referred to hereinafter naturally precede others for the invention to function as described. However, the invention is not limited to the order of the steps described if such order or sequence does not alter the functionality of the invention. That is, it is recognized that some steps may be performed before, after, or in parallel with other steps without departing from the scope or spirit of the invention.

In Step 610, thermoplastic material is provided to extrusion process. The exemplary thermoplastic can be received in either powder or pellet form to be processed into a yarn. The powder or pellet may be either vacuum loaded or gravity fed into an extruder. Example thermoplastics may include polyolefms selected from the group consisting of polypropylene, polyethylene, polybutylene, and other similar thermoplastic materials. Other thermoplastic polymers may also be employed such as the polyamides (nylons), polyesters, or otherwise. These materials may also be used in any combinations or as copolymers.

In Step 620, the thermoplastic material is extruded into yarn. The extruder can include a screw inside of a barrel that forces the thermoplastic through the barrel while heat and pressure are being applied. This may transform the thermoplastic from solid to liquid form. The molten thermoplastic can then forced through a die to give it the desired shape. Dies for slit tape and fϊbrillated tape yarns may be rectangular in shape and the individual ends may slit out of the sheet after the plastic has been transformed from a liquid back to a solid. Monofilament and multifilament yarns can be extruded through individual die holes prior to be transformed back to a solid.

After the thermoplastic goes through the die, it may be quenched or turned back to a solid by either running it through water or exposing it to cool air. After the thermoplastic fiber is turned to a solid from, it can be drawn or oriented to give strength. This may be accomplished by running the fiber through a roller or series of rollers in which the subsequent set of rollers is turning at some predetermined speed that is faster than the previous set. An example of this is a 6:1 draw ratio where the first set of rollers is turning at 100 ft/min and the next set of rollers would be tuning at 600 ft/min. The fiber can be exposed to heat during this drawing/orienting process to soften it while it is being oriented. The heat can be applied through hot water, hot air in an oven, heated rollers, etc. The fiber can now be annealed to remove shrinkage by relaxing the yarn back under heat or it can be wound onto a tube or spool to go to the beaming or weaving process.

In Step 630, the yarn that was extruded in Step 620 is woven into a fabric. Extruded yarn can go to either the beaming or weaving process after being wound onto a spool or tube. The yarn that is utilized in the warp direction can go to a warper or beamer before being placed on the loom. This does not have to be the case as the warp packages can be put into the weaving machine directly from a creel. In either case, specific instructions can be given that detail a pattern of ends and specific ends per inch to be placed on the warp or in the creel. This can determine the pattern as well as coverage the warp direction yarns will provide. The warp direction can also be referred to as the machine direction. After the warp ends are beamed or placed in the creel, the ends can be drawn through a series of heddles prescribed to give the required weave pattern. The heddles can move up and down in a pattern communicated by an electronic board or card readout. This up and down movement along with the filling yarn firing across the loom at each crossing of the heddles can determine the weave pattern. This can serve as what bonds or weaves the fabric together. A pick gear or programmed electronic mechanism can determine the number of picks per inch to be placed in the fabric. This pick level can also determine the coverage the fabric will have from the filling yarn.

In Step 640, an antimicrobial agent 330, such as an algaecide and a bactericide may be applied to the fabric woven in Step 630. The antimicrobial agent 330 may be applied by spraying a solution onto the fabric or also by dipping, soaking, or padding the fabric in a solution of the anti algae/anti fungal agents. An example antimicrobial agent 330 to be used in this step may be MICROBE GUARD DURALAST-I. Another example antimicrobial agent 330 is DURABRAND.

For example, DURALAST-I may be used in materials that are incorporated into manufactured products at the point of manufacturing. The final article may contain from 0.1% to 1.0% (by weight) of the active ingredient. For dipping, soaking, or padding applications, eight ounces of DURALAST-I may be diluted into one gallon of water prior to completely submerging the fabric into the solution for 3 minutes. For spray application, eight ounces of DURALAST-I may be diluted per gallon of water prior to application of the solution to the fabric.

In Step 650, one or more fabric finishing steps may be applied to the fabric that was woven in Step 630. Once the fabric is woven, the fabric roll can be processed through one or more finishing step or the fabric can be shipped out as is. The woven pool cover fabric may be calendared after weaving. Some woven pool cover fabrics may be tentered in order to remove residual shrinkage in the plastic or maintain a width tolerance on the fabric. The calendar can be used to crush the fabric to a specific air flow or thickness through a combination of heat and pressure. The calendar can consist of two heated steel rollers. One of the rollers can be situated above and the second below a fiber roll that can be made of many different materials. The fabric can be threaded between the steel rolls and the fiber roll to subject it to heat and the upward and downward pressure of the steel rolls. The pressure may be controlled by hydraulics.

Note that Steps 640 and 650 in particular may be performed in the order illustrated, or in reverse order. Furthermore, Step 640 maybe be performed between two of the finishing steps of Step 650.

In Step 660, the fabric that was woven in Step 630 and finished in Step 650 can be formed into a cover, such as pool covers 300, 400. The fabric can be cut into the length and shape needed to cover a pool. Since the woven good may not be wider than 73 inches in some exemplary embodiments, three or more pieces can be connected to cover the width of the pool. The pieces can be sewn together. A woven nylon strap can be attached at the seam and also periodically across the cover, every three feet for example. These straps can be sewn to the fabric in both the width and length direction. This nylon strapping can be approximately one inch wide and can be woven using an ultraviolet (UV) stabilized multifilament yarn. The nylon strapping can extend past the edge of the cover from 12 inches to 24 inches. This nylon length can be attached to a hook or apparatus that can slide over a peg to stretch the cover taunt and suspend it above the water surface. In Step 670, the cover that was fabricated in Step 660 can be applied to a swimming pool by an installer or end user in the field. The woven cover can be suspended above the water level of a pool. The height above the water level can vary depending on the water level when the cover is installed and the amount of rain during the period of time the cover is installed. The cover can extend past the edge of the pool for approximately six to twelve inches around the entire circumference of the pool. As a performance example, a pool cover may remain on a pool from seven to nine months (or more) depending on the climate where the pool is located. In Step 680, the cover that was applied to the swimming pool in Step 670 can be exposed to environmental water. In addition to the water in the swimming pool, environmental water may include rain, snow, water from other sources, or any combination thereof.

In Step 690, the antimicrobial agent 330 within the cover can form a zone of inhibition within the environmental water, such as in the water of the swimming pool. The incorporation of antimicrobial agent 330 may substantially stop algae, bacteria, fungi and/or other microbes from growing on the cover while it is installed or stored. Furthermore this benefit may extent into the surrounding environment and environmental water, such as the water in the swimming pool. The antimicrobial agent 330 may also prevent the growth of algae, bacteria, fungi and/or other microbes from items contaminated and falling on the surface of the cover.

From the foregoing, it will be appreciated that an embodiment of the present invention overcomes the limitations of the prior art. Those skilled in the art will appreciate that the present invention is not limited to any specifically discussed application and that the embodiments described herein are illustrative and not restrictive. From the description of the exemplary embodiments, equivalents of the elements shown therein will suggest themselves to those skilled in the art, and ways of constructing other embodiments of the present invention will suggest themselves to practitioners of the art. Therefore, the present invention is to be provided the scope set forth by the claims that follow.

Claims

CLAIMSWhat is claimed is:

1. A woven pool cover fabric comprising: a thermoplastic warp yarn; a thermoplastic weft filling yarn; and an antimicrobial agent applied to the yarn, wherein the antimicrobial agent is soluble with water and forms a zone of inhibition adjacent to the yarn.

2. The woven pool cover fabric of Claim 1, wherein the thermoplastic comprises one of polyolefϊn, polyester, and polyamide.

3. The woven pool cover fabric of Claim 1, wherein the thermoplastic comprises polypropylene.

4. The woven pool cover fabric of Claim 1, wherein the thermoplastic warp yarn and the thermoplastic weft filling yarn each comprise a thermoplastic base material, and the antimicrobial agent is incorporated into the thermoplastic base material.

5. The woven pool cover fabric of Claim 1, wherein the antimicrobial agent is incorporated into a surface of both the thermoplastic warp yarn and the thermoplastic weft filling yarn.

6. The woven pool cover fabric of Claim 1, wherein the woven pool cover fabric comprises 0.1% to 2.0% antimicrobial agent.

7. The woven pool cover fabric of Claim 1, wherein the antimicrobial agent seeps from the woven pool cover fabric and into a surrounding environment.

8. The woven pool cover fabric of Claim 1, wherein the antimicrobial agent comprises and algaecide.

9. The woven pool cover fabric of Claim 1, wherein the antimicrobial agent comprises one of a bactericide and a fungicide.

10. A process for manufacturing a woven fabric containing antimicrobial agents, comprising the steps of: providing a thermoplastic base material; applying an antimicrobial agent to the thermoplastic base material; coextruding the thermoplastic base material and the algaecide or bactericide into one or more yarns; and weaving the one or more yarns to form a woven fabric.

11. The process of Claim 10, further comprising the step of finishing the woven fabric.

12. The process of Claim 10, further comprising the steps of fabricating a pool cover from the woven fabric; and installing the pool cover onto a swimming pool.

13. The process of Claim 10, further comprising the step of applying the woven fabric as a building material or as a geotextile.

14. The process of Claim 10, further comprising the step of allowing the antimicrobial agent to seep into an environment adjacent to the woven fabric.

15. A process for manufacturing a woven fabric containing antimicrobial agents, comprising the steps of: providing a thermoplastic base material to an extruder; extruding the thermoplastic base material to form one or more yarns; weaving the one or more yarns to form a woven fabric; and applying an antimicrobial agent to a surface of the woven fabric.

16. The process of Claim 15, wherein the step of applying an antimicrobial agent to a surface of the woven fabric comprises spraying the antimicrobial agent on to the surface of the woven fabric.

17. The process of Claim 15, wherein the step of applying an algaecide antimicrobial agent to a surface of the woven fabric comprises dipping, soaking, or padding the woven fabric in a solution of the antimicrobial agent.

18. The process of Claim 15, further comprising the steps of fabricating a pool cover from the woven fabric; and installing the pool cover onto a swimming pool.

19. The process of Claim 15, further comprising the step of applying the woven fabric as a building material or as a geotextile.

20. The process of Claim 15, further comprising the step of allowing the antimicrobial agent to seep into an environment adjacent to the woven fabric.