Patent Publication Number: US-2015074916-A1

Title: Method  and aparatus for applying nanoparticle surface treatments inside a container

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/879,246 filed Sep. 17, 2013 titled “Method to apply nanoparticle surface treatments inside a sealed bag.” 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is in the field of nanoparticle coatings and aspects of the invention pertain particularly to methods and apparatuses for applying nanoparticle coatings inside a sealed bag. 
     2. Summary of the prior art 
     In U.S. Pat. No. 8,512,417, a chemical process is taught that links or bonds nanoparticles to surfaces. In that patent, an external stimulus is used to encourage/activate a linker. That patent does not describe how the external stimulus is to be applied or even what the stimulus is. 
     U.S. Pat. No. 7,811,627 B2 entitled Papermaking Fabrics with Contaminant Resistant Nanoparticle Coating and Method of in situ Application, discloses the application and selective stimulation of nanoparticle coatings. Particularly, the patent discloses a nanoparticle type coating that is applied to an industrial textile and then cured in a separate operation with the use of heat. However this patent does not disclose a method for the contained application of the nanoparticle type coating. 
     U.S. Pat. No. 7,141,518 B2 entitled Durable Charged Particle Coatings and Materials discloses the binding of high surface area materials to substrates. This patent discloses a fabric being exposed to ultrasonic energy while within a bath of aqueous high surface area material, the ultrasonic energy used to promote bonding. However, this patent does not disclose a means for containing the high surface area material. 
     U.S. Pat. No. 7,112,621 B2 entitled Coating Compositions for Modifying Surfaces discloses methods and articles of manufacture comprising a nanoparticle system for imparting surface modifying benefits for all types of soft surfaces. The patent discloses coating compositions applied by hand or a machine. Particularly, distribution of the coating composition can be achieved by using a wide variety of application methods and devices, including but not limited to: spray devices, immersion containers, printers, washing machines, spray hose attachments, rollers and pads. However, the patent does not disclose an apparatus or method that employs a sealed container or bag. 
     It is apparent that there is a need for a method for efficiently applying functionalized coatings to textiles fabrics wherein the coating is applied within a contained environment. Further there is a need for apparatuses that enable the performing of such a method wherein a functionalized coating is applied and activated within a sealed bag. 
     SUMMARY OF THE INVENTION 
     One aspect of the present invention is directed to an apparatus for applying a surface coating to a target surface. The apparatus employs a containment means for a surface coating and a means for infusing a target surface with the surface coating onto the target surface once the containment means in sealed. In operation, this apparatus permits the application of a nanoparticle surface coating on to a target surface while limiting the environmental exposure of the nanoparticle surface coating. With certain nanoparticle coatings, such as with silver based nanoparticle coatings, it is desirable to contain the surface coating such that in only comes in contact with the target surface. 
     An additional aspect of the invention is directed a method of applying a coating to a target surface. In one embodiment, the method is directed toward applying antimicrobial surface coatings to substrates via the steps of proving a containment means and surface coating, inserting a target surface into the containment means, and sealing the containment means, and subjecting the containment means to an external stimulus. This method is desirable for coating target surfaces when the external stimulus is used to accelerate the application of the surface coating is supplied via a mean such as a residential dryer where it is desirable to prevent the surface coating from coming in contact with the dryer. 
     Various objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention, along with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts an apparatus adapted to practice one embodiment of the method envisioned by the invention. 
         FIG. 2  depicts a flow chart of one embodiment of a method practiced according to the present invention. 
         FIG. 3  depicts an embodiment of the invention with sealed regions within the container. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     At the outset, it should be appreciated that while the present invention is described with respect to what is presently considered to be the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. 
     One aspect of the invention described herein is a novel method for supplying external stimulus to catalyze/activate a cross-linking reaction that will permanently bond or link sub-micron particles or nanoparticles to surfaces to impart new properties to those surfaces. In one embodiment, a target surface, along with a linker and sub-micron particle, or nanoparticle is placed in a sealed, durable bag. In such an embodiment, the bag is then subjected to a heating cycle. The heating cycle supplies heat as a cross-linking stimulus. In one embodiment the contents of the bag are mixed and evenly distributed by shaking the bag before subjecting it to a heating cycle. Alternatively, the contents inside the bag may be mixed and evenly distributed by an action associated with the means of providing a heating cycle, such as occurs inside a clothes dryer. Still further, the contents of the bag may be removed from the sealed bag and then subjected to the heating cycle. 
     In this disclosure, the term “sealed” or “sealable” is used to refer being or having the property of being closed or being able to be closed in a liquid tight fashion. However, being “sealed” or “sealable” is intended to encompass means of containment that while liquid impermeable are gas permeable and/or have a mechanically activated vent. 
     Also, for the purposes of this disclosure, antimicrobial is understood to refer to the property of being capable of destroying or suppressing the growth of harmful microorganisms whether bacteria, viruses, or fungi, on inanimate objects and surfaces. Additionally, nanoparticles are defined as discreet particles either suspended or dissolved in solution or dry powder, with one or more dimension on the 1 nm to 100 nm scale range. The definition of nanoparticles includes materials with nano-sized dimensions that are spheroidal, tubes, rod-shaped, wires, cubic, aggregates, nanotubes, among others. 
     Referring to  FIG. 1 ,  FIG. 1  shows an apparatus adapted for performing an embodiment of the new method. A target surface  4 , is placed in a sealable bag  2 , along with water  6 , and a surface coating  8 . Then, the sealable bag  2  is sealed, and the sealable bag  2  now containing the target surface  4 , water  6  and surface coating  8  is subjected to an external stimulation. 
     Referring to the sealable bag  2  in more detail, the sealable bag  2  is a form of containment means utilized in one embodiment of the invention. In this embodiment, the sealable bag  2  is constructed from a plastic and utilizes a zip-locking type sealable closure. Alternatively, the sealable bag  2  can utilize a Velcro, a twist tie, or a snap closure in order to be sealable. Still further, the containment means can be sealable via roll top closure as used in dry bags. 
     Referring to the surface coating  8  in more detail, the surface coating  8  may be poured into the sealable bag  2 . However, in the preferred embodiment, the surface coating  8  is contained in breakable, burstable or dissolvable containers or cartridges inside the bag. Burstable containers may be achieved by providing a container with a welded seam between two compartments that opens when a pressure is applied to one of the compartments. One benefit of containing the surface coating  8  inside a sealed container or cartridge that remains sealed until inside the sealable bag  2  is that the sealable bag  2  acts to separate and contain the surface coating from a user, prior to a reaction taking place. 
     Referring to the composition of the surface coating  8  in more detail, the invention envisions the use any type of surface coating. However, in the preferred embodiment, the surface coating  8  is comprised of a cross-linking agent and a nanoparticle contained in separate containers or cartridges. The cross-linking agent can be the linker material described in patent U.S. Pat. No. 8,512,417 B2. In other embodiments it can be one of numerous cross-linking agents that promote/catalyze reactions using one or more stimuli including thermal, optical (UV/VIS, RF) electromagnetic, and chemical among others. Examples include peroxides, epoxides, silanes, siloxanes, silicones, urethanes, acrylates, azides, triazenes, diazirines, imides, and polyimides among others. 
     In the preferred embodiment, the nanoparticles are silver nanoparticles. The preferred embodiment uses the silver nanoparticles as an antimicrobial treatment. The silver nanoparticles can be applied for other purposes including electronic, antistatic or shielding. In other embodiments, sub-micron and nano-sized materials of metals, metal oxides, polymers, semiconductors, biomolecules, or composites thereof, with and without stabilizers, can be used to impart a variety of properties to treated surfaces including air cleaning, antistatic, antibacterial, antifungal, pesticidal, reflective, hydrophobic, hydrophilic, flame- retardant/heat resistant, UV-blocking, scent-releasing, odor-absorbing, abrasion-resistant, color-brightening, and authentication among others. The sub-micron particles and nanoparticles can be in the form of spheres, rods, tubes, prisms, platelets, fibers, or irregular geometries as a dry powder, slurry, dissolved solution, or in other dispersed media. Additional embodiments include combinations of one or more nanoparticle to impart multiple properties to the treated surface. For example, hydrophobic nanoparticles could be mixed with silver nanoparticles to impart hydrophobicity and antimicrobial action. 
     Referring to  FIG. 2 ,  FIG. 2  is a flow chart depicting a method practiced in accordance with one embodiment of the invention. A containment means is provided  22 . A target surface and surface coating are then inserted  24 ,  26  into the containment means. The containment means is then sealed  28 . Lastly, the containment means which now contains the target surface and a surface coating is subjected to an external stimulation  30 . 
     Referring to the providing a containment means step  22 , the containment means may take different forms in alternative embodiments. In the preferred embodiment, the containment means is a sealable bag  2  such as depicted in  FIG. 1 . In other embodiments, the containment means could be a pan or tub. 
     Referring to the inserting a target surface step  24 , the target surface is a textile fabric in the preferred embodiment. Examples of textile fabrics include sports apparel, undergarments, hosiery, shoes, socks, pet products, hats, bags, purses, wallets, packs and beds. In addition, carpet, upholstery, draperies and rugs can be treated. The target surface may additionally be a hospital carpeting and upholstery, automotive carpeting and upholstery along with airplane cabin carpeting and upholstery. Still further, the target surface may be a rigid product or products like helmets, shoulder pads, shin guards and other sporting goods. 
     Referring to the inserting surface coating step  26  in more detail, in the preferred embodiment, the surface coating may be inserted into the containment means by way of a breakable, burstable or dissolvable containers or cartridge. In alternative embodiments, the surface coating can be inserted via pumping, pouring, pressure dispensing or methods suitable for dispensing a controllable amount of surface coating. Furthermore, in some embodiments, the surface coating may refer to a combination of water and coating agents which can be contained in breakable, burstable or dissolvable container or cartridges. 
     In the preferred embodiment, once the containment means contains the target surface and the surface coating, the containment means is sealed  28 . The containment means may be sealed in a one time or re-sealable manner. The containment means may be sealed via a snap type or adhesive closure. During this step, if the surface coating is contained within a burstable or breakable container or cartridge, the container or cartridge may be burst or broken, thus dispersing the surface coating within the containment means. The release of the surface coating infuses the target surface with the surface coating. 
     After the containment means is sealed  28 , the containment means is then subjected to an external stimulation  30 . In the preferred embodiment, the external stimulus is heat which can be supplied by placing the containment means in a household dryer for a drying cycle. In alternative embodiments, the external stimulation may be UV light suitable for to activating a UV-activated surface coating, or RF or other EM radiation to inductively heat the surface coating, sonic energy or combinations thereof. 
       FIG. 3  depicts an embodiment of the sealable bag  2  that contains a first sealed region  32  and a second sealed region  34 . The first sealed region  32  and second sealed region  34  are burstable whereby the contents of the first and second sealed region  32   34  may be selectively released into the containment means. The first sealed region  32  and second sealed region  33  can be produced by RF welding the sealable bag  2  such that when a pressure is applied to the first sealed region  32  or second sealed region  34 , the RF weld will burst releasing the contents of the first or second region into the sealed bag. This apparatus allows the selective release of the contents of the first sealed region  32  and second sealed region  34  into the general volume defined by the sealable bag  2 . 
     Furthermore, it should be understood that aspects of the invention are not limited to the particular methodology, materials and modifications described above and as such may vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention.