BACKGROUND OF THE INVENTION

1 , Field of the invention

Generally, the present invention relates to the field of water containers More specifically, the present invention relates to a growth resistant water container.

2. Description of the Related Art

Microbial contamination is a universal concern and can occur by a person touching the same surface as another person. Devices that are known to transfer microbes through touch include door handles, toilet handles, waste container, utensils, water faucet and other products which come into contact with human beings.

One approach to reducing the communication of microbes between people is to coat the surface of such devices with an antimicrobial coating. The microbes transferred from one person to the surface are killed or substantially reduced in number by the antimicrobial agents on the surface of the device. This limits the undesired transfer of the microbes to other people who may come into contact with the device.

Numerous products have been developed containing antimicrobial coatings as part of an exterior surface for use in preventing the transmission of microbes. One common approach has been to mix an antimicrobial metal with a resin and apply it to the surface of the device where the device is susceptible to contamination. However, these coatings tend to have problems with adhesion and are therefore limited in the surfaces to which the material can be applied. Another issue with these types of coatings is that the resins tend to encapsulate the antimicrobial metal and reduce its ability to effectively kill microbes on the actual surface.

Another problem, in addition to concerns of contamination, there are concerns regarding the ability to reuse materials. The increased desire to recycle and repeatedly use materials has spawned a need for materials that can inhibit growth and be used repeatedly. Prior to now there has been little success with regard to the creation of containers formed of materials that are antimicrobial and reusable.

SUMMARY OF THE INVENTION

According to the present invention there is provided a liquid container that is resistant to the growth of certain microbiological species such as bacteria and fungi. The liquid container resists growth and is capable of being reused.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows three external views of one embodiment of a container.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Generally, the present invention provides a plastic product infused with at least one silver containing composition for preventing microbial growth on the surfaces of the product.

The term“product” as used herein is intended to include any plastic item and more specifically a plastic item for holding a liquid, such as water, intended to be used for human consumption. This can include, but is not limited to, water bottles, water containers, water tanks, water holding devices, showers, bath tubs, and hot tubs.

As used herein, the term "antimicrobial" includes preventing or inhibiting the growth of microorganisms or imparting biostatic activity, i.e., where the proliferation of microbioiogical species is reduced or eliminated, and true biocidal activity where microbiological species are killed. Furthermore, the terms "microbe” or "microbial" should be interpreted to encompass bacteria and fungi as well as other single-celled organisms such as mold, mildew and algae.

The antimicrobial agents utilized in the practice of the invention form an antimicrobial additive composition for imparting antimicrobial characteristics to plastic materials and articles made from such materials. In particular, these agents impart antibacterial and antifungal characteristics to plastic materials at an acceptable cost and without disrupting manufacturing processes and without unacceptably altering the end product. The antimicrobial agents include at least one silver containing composition and possibly other antimicrobial agents such as the commercially available Microban© products.

The antimicrobial agent can be a silver containing composition can include silver, and may also include copper or zinc in various forms, such as in zeolite or amorphous glass powder. Silver, for example, alternatively may be utilized in the elemental form or in sol/geS form; the general concept being that the inorganic antimicrobial agent be disposed in the plastic product in an ion exchangeable form. Also, zinc oxide can be added to the dispersion to stabilize the antimicrobial agent,

In some cases, it may be desirable to add a dispersing agent with the antimicrobial agent to prevent agglomeration of the antimicrobial agent. The dispersing agent can be any dispersing agent known to those of skill in the art to be used in the product that does not react with any of the antimicrobial agents.

The antimicrobial ageni(s) is/are dispersed in the plastic material prior to its formation as the final product. As one example, the antimicrobial agent may be delivered as a fine divided powder diluted in a liquid forming a dispersion, which can be admixed with the plastic material. The weight percent addition of the antimicrobial agents are about 0.1 % to about 5%, with a preferred range of about 2.75% to about 3.5% of the weight of the plastic. Other compounds can also be added to the plastic to aid in the antimicrobial property. By way of example, zinc oxide can be added to the dispersion to stabilize the antimicrobial agent.

Compounding additives, in addition to the antimicrobial agent, can include; surface active agents such as wetting agents, surfactants, deaeratanis, and defoamers; antiblocking agents; catalysts such as PTSA (para-toluene sulfonic acid), MSA (methane sulfonic acid), oxalic acid, ammonium nitrate and ammonium chloride; fillers; pigments; dielectric modifiers; glossing agents; and dyes.

Latent acid catalysts, such as those having a fugitive counter ion, like ammonium nitrate and ammonium chloride, are preferred where the storage time will be lengthy. Generally speaking, the strong acid catalysts are used in melamine formaldehyde systems where the melamine is highly methylated, such as hexamethoxymethylmelamine.

More specifically, the preferred antimicrobial additive composition for imparting antimicrobial characteristics to a plastic material according to the present invention includes a quantity of an antimicrobial agent, sold by the Microban International, LTD under the tradename Mibroban® Polymer Additive 1814-1814-100. The materia! includes silver ions as well as other additives to both provide the necessary antimicrobial properties as well as properly disperse within the material in need of the antimicrobial protection. The material is incorporated into the raw plastic before it is formed into the final product. The additive is mixed evenly throughout the whole body of the plastic, such that only a small portion of the additive is on the surface of the item at any time. This small amount of additive is what prevents microbial growth. The weight percent addition of the antimicrobial agent is about 0.1 % to about 5%, with a preferred range of about 2.75% to about 3.5% of the weight of the plastic.

The acrylics group of polymers is dominated by two resins-one used principally for blending with other resins and as a fiber (polyacrylonitrile or PAN) and the other used principally for molding (polymethylmethacrylate or PMMA). The antimicrobial agent can also be used in polyethylene and polyethylene terephthaiate materials as are commonly used for making bottles. Other materials can also be used without departing from the spirit of the invention.

The molding resin, PMMA, is a very popular engineering thermoplastic material. Common brand names for PMMA include Perspex®, Plexiglas®, Lucite®, Aery! lie®, ModenGlass®, and Diakon®. The resin is polymerized by the addition polymerization method and forms a plastic that is atactic and therefore amorphous.

What is desired is a plastic product that has built-in antimicrobial protection that reduces or substantially eliminates the proliferation of bacteria, algae, fungi, and other microbes on its surface. Such a product would also reduce and/or substantially eliminate the need for exterior treatment.

Although some of the known acrylic or other plastic products having built-in antimicrobial agents demonstrate some efficacy against the buildup of microorganisms, there is a continuing need for more efficacious antimicrobial plastic products. Thus, incorporation of the antimicrobial agent as disclosed herein prior to formation of the final product allows creation of a product with the antimicrobial properties included.

The products incorporating the antimicrobial agent of the invention may be formed using either an extrusion, blow molding, or a casting process and may be utilized in either a continuous or batch process. The invention is also suitable with curing conducted at room temperature or at an elevated temperature and is thus compatible with many different cure chemistries.

The composition of the acrylic material Is selected according to the application in which the material is to be used. For example, if the material is intended to be cast in a sheet for subsequent thermoforming, e g., to form a tub or spa; then an acrylic material formulated for casting and thermal molding should be selected. Likewise, if the material is intended to be extruded those skilled in the art may alter the composition for extrusion purposes without undue experimentation.

Blow molding is a well-known technique that is used for manufacturing plastic articles such as bottles, containers, automobile parts, or cases. In a one-stage or "single- stage" blow molding machine, the process begins with manufacture at a first station of a hot, injection molded preform or "parison" of hollow plastic material, the preform further conditioned at a second station and then moved and positioned at a third station which has a mold cavity with interior walls in the shape of the final article to be molded in a "two-stage" machine the preforms are manufactured externally, but transported to and reheated at a conditioning station before moving to the blow cavity.

Injection stretch blow molding (ISBM) is a term of art and refers mostly, if not entirely, to biaxial PET blow molding from preforms. 1SBM techniques date back only about 35 years. Some blow-molded plastic bottles are blown from an extruded tube that the closing mold pinches off at the bottom end. !SBM is used to provide a plastic container or other useful article of manufacture created on a machine from a pre-form, which is first stretched in the axial direction, and then blown In a mold by high pressure air in the hoop direction. The hot preform may be manufactured via an injection mold station on a "one- stage" or "single-stage" stretch blow mold machine, whereafter the preform is temperature conditioned, and then stretch blow molded into a final article, and finally cooled on the same machine before ejection. The typical sequence of operations in a single-stage ISBIVf machine is as follows. PET is delivered to the machine site, usually in small flake form contained in sizeable boxes {"gaylords"). Once the gaylord box is opened, the PET particles immediately begin absorbing excessive levels of moisture from the ambient air. Thus, virtually all single- stage !SBM machines run the PET material through a dryer. The material then enters a ''manifold" meant to maintain PET heat and dryness during transport to the preform molding station, where the parison is formed by injecting liquefied PET material along with the antimicrobial agent into a mold cavity, with parison thickness and its internal profile a function of the shape of the preform insertion rod lathed to specifications. Once cooled enough to transport, the molded preform moves to a conditioning station, where optimal (e.g., article-specific) pre-blow temperatures are achieved for the parison, both internally and on its exterior surface. The conditioned parison then moves to the blow station, where compressed air works with a stretch rod to expand the PET resin until contact with the mold cavity wails, at which point the PET resin quickly cools and hardens, after which the mold is opened to allow article ejection.

For packaging liquid foods and other pourable substances, for example, cleaning agents, body care agents, cosmetics, automotive media, etc., mainly containers made of plastic are used today. However, many conventional plastics gain their special properties only by means of stretching. For example, polyethylene terephthalate (PET) is a very popular plastic which achieves a strength level several times higher than that of unstretched PET only by stretching, and this influences the degree of crystallization. Bottle-shaped plastic containers in particular are therefore often produced in a so-called injection stretch blow molding process.

First, in an injection casting process, a preform is produced in an injection mold. The preform normally has an essentially elongated cylindrical body that is closed on one longitudinal end and is embodied with an opening on the other end. A supporting ring expediently separates the body from a neck part having a spout opening. The neck part may already have the subsequent shape of the neck of the bottle. A thread or some other means for fastening a container closure may be formed on the outside or inside of the neck part. After it has been produced, the preform is unmoided and processed further immediately or stored temporarily for subsequent processing by a blow molding machine. Before further processing in a blow molding machine, the preform may be conditioned, if necessary. After this, it is introduced into a blow molding mold on the blow molding machine, where it is stretched using a stretching mandrel {which is also referred to as a "stretching rod," "stretching mandrel, " "stretching ram" or "core rod") and blown by a gas injected into the preform in accordance with the mold cavity of the blow molding mold. After conclusion of the blow molding process, the finished plastic bottle can be unmolded. This second part of the injection stretch blow molding process is a stretch blow molding process. In the two-step injection stretch blow molding process, a preform is produced in the first step and then in the second step the preform is stretched and blow molded to form the bottle(stretch blow molding process), wherein the two steps in the two-step injection stretch blow molding process are carried out at separate locations and at separate times. In contrast with that, both take place together locally and chronologically in a so-called one-step injection stretch blow molding process (or synonymous: "one-step injection stretch blow molding process"), i.e., production of the preforms and the bottle in the same machine (the preform is not cooled completely; only cooled from the injection temperature, which is usually approx. 270°C, to the blow molding temperature, which is approx. 100°C).

For the sake of thoroughness, it should be pointed out that, in addition to the injection stretch blow molding process, blow molding processes in which a slight stretching and blow molding take place immediately following injection of the preform can also be used in such processes, the preform remains on the injection core which at the same time forms a type of stretching mandrel. This resembles the one-step injection stretch blow molding process, but the longitudinal stroke of the injection core is usually only a few millimeters. Since the preform Is stretched only slightly here, we are speaking of the so-called injection blow molding process, in contrast with the injection stretch blow molding process, which is of interest in conjunction with the present invention. In the known injection blow molding process, the preform comes in contact with the injection core. In the two-step injection stretch blow molding process, preforms are stretched to a much greater extent in blow molding than in injection blow molding; for example, in the case of PET preforms, they are stretched to two to five times the diameter and two to five times the length. The stretching and blow molding of the preform in the two-step injection stretch blow molding process are carried out on a different machine than production of the preform, i.e„ the injection molding process, and there is usually intermediate storage of the preform, so the preform cools down between the injection molding process and the stretching and blow molding, namely to at least room temperature. However, in order to be able to be stretched, the preform must be softened, which is achieved by prior heating of same in an oven. The stretching process is carried out by the blow molding process, on the one hand, and by the stretching mandrel, on the other hand.

The stretching mandrel is inserted through the opening in the preform and into the preform, which is in the blow molding mold, until it reaches the closed end, i.e., the bottom of the preform. The movement of the stretching mandrel Is continued, so that pressure is exerted on the bottom and the preform is stretched (shaped) in length until it reaches the wail of the blow molding mold. Due to this deformation, the preform becomes longer, but it is smaller in diameter. Since the contact with the stretching mandrel is desired only in the bottom area, at the same time a small amount of air is injected, countering this contraction and largely preventing contact and cooling of the preform with the stretching mandrel in the body area. Injection of this small amount of air is usually referred to as the so-called preliminary blowing. Next there is the actual blowing ("main blowing") as described above.

If, on insertion, the stretching mandrel has already come in contact with the inside wall of the preform laterally in the area of the body, this area will cool rapidly at the contact point, which can result in rupture of the preform or to an irregular distribution of wall thickness in the blow molded container because the cooler contact point cannot be stretched to the same extent. This problem is reinforced by the fact that, after passing through the oven, the preform is soft and is never positioned entirely accurately after being introduced into the blow molding mold. As a rule, the preform will sit in a slightly skewed position in the blow molding mold or will not be centered ideally or may even be curved. There is also the possibility that the stretching mandrel is not positioned ideallycentrally or is slightly shaped.

Preforms with a diameter of approx. 2 centimeters are generally used for bottles with a capacity of one-half liter, which may have a diameter of approx. 8 centimeters. Such a diameter allows a sufficient distance between the stretching mandrel and the inside wall of the preform on insertion of the stretching mandrel, so that the problems described above involving local contact do not occur. With the smaller bottles of 100 or 200 milliliters, for example, the diameter of the bottles and thus also the diameters of the preforms from which they are produced are much smaller. Accordingly, the opening through which the stretching mandrel is inserted or at least the inside diameter of the body of the preform is smaller.

If the opening in the preform or the inside diameter of the body of the preform has a diameter of less than 1 centimeter, the result is extensive problems with the mechanical engineering In other words, if the diameter of the stretching mandrel is only slightly smaller than the inside diameter of the preform, then, when the stretching mandrel is inserted, there will be contact and therefore local cooling of the preform, with the consequences described above. However, if the diameter of the stretching mandrel is much smaller than the inside diameter of the preform, then the stretching mandrel will no longer be able to withstand the forces that occur during stretching and will bend or even break. Furthermore, there is the risk that because of its small diameter it will puncture the bottom of the preform, which will make stretching impossible.

Figure 1 (a) (b) and (c) show external perspective views of one embodiment of a container 10 of the disclosure. In this Figure, the container is shown without a cap to show a threaded portion 12 on the container. In this embodiment, the container holds about 20 ounces.

Those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed herein andstill: obtain a like or similar result without departing from the spirit and scope of embodiments disclosed herein.

Throughout this application, author and year and patents by number reference various publications, including United States patents. Full citations for the publications are listed below. The disclosures of these publications and patents in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertains.

The invention has been described in an illustrative manner, and it is to be understood that the terminology, which has been used herein, is intended to be in the nature of words of description rather than of limitation.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings it is, therefore, to be understood that within the scope of the described invention, the invention can be practiced otherwise than as specifically described.