US20040191500A1

US20040191500A1 - Anti-microbial fiber and fibrous products

Info

Publication number: US20040191500A1
Application number: US10/785,850
Authority: US
Inventors: Stephen Foss
Original assignee: Foss Manufacturing Co Inc
Current assignee: FOSS MANUFACTURING COMPANY LLC
Priority date: 1999-05-27
Filing date: 2004-02-24
Publication date: 2004-09-30
Also published as: US6723428B1; US20040197553A1; US20030170453A1; CA2375567A1; EP1212478A4; WO2000073552A1; US20040214495A1; US20050019568A1; MXPA01012196A; US20050101213A1; US6946196B2; AU5162800A; US20040202860A1; US6841244B2; EP1212478A1; US20050106390A1; US20050003728A1; US20040209059A1; CA2375567C

Abstract

An anti-microbial sheet or film and various products made partially or wholly therefrom comprised of inorganic anti-microbial additives, distributed in certain areas to reduce the amount of the anti-microbial agents being used, and therefore the cost of such products. The products can incorporate anti-microbial additives so that they are not removed by repeated washing in boiling water and in dry clean cycles and become ineffective and conversely enhance access to the additives by washing or the like. The products comprise high tenacity polymers (e.g. PET) in one portion and hydrolysis resistance polymers (e.g. PCT) in another portion with the additives.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of Ser. No. 09/565,138 filed May 5, 2000 which claims the priority of the following provisional applications: Serial No. 60/136,261, filed May 27, 1999; Serial No. 60/173,207, filed Dec. 27, 1999; Serial No. 60/172,285, filed Dec. 17, 1999; Serial No. 60/172,533, filed Dec. 17, 1999; Serial No. 60/180,536, filed Feb. 7, 2000; Serial No. 60/181,251, filed Feb. 9, 2000; and Serial No. 60/180,240, filed Feb. 4, 2000.[0001]

FIELD OF THE INVENTION

The present invention relates generally to products having anti-microbial (and/or anti-fungal) properties which remain with the product after repeated launderings/uses. More specifically it provides wide sheet materials that are made of a wholly or partly synthetic material and having anti-microbial and anti-fungal properties. Such sheets can be used with other synthetic or natural materials to form a variety of different end use products. This invention provides for sheet materials for end use products that are resistant to bacterial and fungal growth as well as to the deterioration of the agents contained in these materials. There is a laminate embodiment which relates to generally to laminate materials, and, more particularly that are made of a wholly thermoplastic stiff reinforcing multiple laminate moldable into compound shapes and bondable via a thermoplastic hot melt adhesive to a carrier surface to be reinforced.

BACKGROUND OF THE INVENTION

There is a growing interest today in products which have anti-microbial and anti-fungal properties. There are a number of additives, fibers and products on the market which claim to have these properties. However, many do not have such properties, or the properties do not remain for the life of the product, or they have adverse environmental consequences.

Various materials have been used in the past to provide anti-microbial and anti-fungal properties to fibers and fabrics.

Examples of some organic types of anti-microbial agents, are U.S. Pat. Nos. 5,408,022 and 5,494,987 (an anti-microbial polymerizable composition containing an ethylenically unsaturated monomer, a specific one-, di- or tri-functional anti-microbial monomer and a polymerization initiator which can yield an unreleasable anti-microbial polymer from which the anti-microbial component is not released), U.S. Pat. No. 5,709,870 (a silver containing anti-microbial agent which comprises carboxymethylcellulose, a crosslinked compound, containing silver in the amount of 0.01 to 1% by weight and having a degree of substitution of carboxymethyl group of not less than 0.4 and the anti-microbial agent being a silver salt of carboxymethylcellulose, which is insoluble to water), U.S. Pat. No. 5,783,570 (an organic solvent-soluble mucopolysaccharide consisting of an ionic complex of at least one mucopolysaccharide and a quaternary phosphonium, an antibacterial antithrombogenic composition comprising organic solvent-soluble mucopolysaccharide and an organic polymer material, an antibacterial antithrombogenic composition comprising organic solvent-soluble mucopolysaccharide and an inorganic antibacterial agent, and to a medical material comprising organic solvent-soluble mucopolysaccharide).

Examples of some inorganic types of anti-microbial agents are:

Japanese Patent No. 1246204 (1988) which discloses an anti-microbial thermoplastic article with copper a compound added to the melted polymer just before extruding, in which the anti-microbial material is said to be resistant to washing.

U.S. Pat. No. 5,180,585 which discloses an antimicrobial with a first coating providing the antimicrobial properties and a second coating as a protective layer. A metal having antimicrobial properties is used including silver which is coated with a secondary protective layer.

Japanese Patent No. 2099606 (1990) which discloses a fiber with anti-microbial properties made of a liquid polyester and inorganic micro particles of zinc silicate, both being added to the melted polymer after polymerization and just before extrusion.

The use of anti-microbial agents in connection with thermoplastic material is known from U.S. Pat. No. 4,624,679 (1986). This patent is concerned with the degradation of anti-microbial agents during processing. This patent states that thermoplastic compounds which are candidates for treatment with anti-microbial agents include material such as polyamides (nylon 6 or 6,6), polyvinyl, polyolefins, polyurethanes, polyethylene terephthalate, styrene-butadiene rubbers.

Japanese Patent No. 2091009 (1990) and U.S. Pat. No. 5,047,448 disclose an anti-microbial thermoplastic polymer with copper or zinc compounds and fine particles of Al, Ag, Fe and Zn compounds and a liquid polyester, in which the anti-microbial material is said to be resistant to washing.

Japanese Patent No. 2169740 (1990) discloses a thermoplastic fiber such as PET which uses silver, copper or zinc as an anti-microbial agent. There is a cellulose component which reduces the amount of thermoplastic with anti-microbial agent and reduces the cost.

Examples of inorganic types of anti-microbial agent which have zeolite with silver is disclosed in U.S. Pat. Nos. 4,911,898, 5,094,847, 4,938,958 (use of zeolite with exchangeable ions such as silver and others), U.S. Pat. No. 5,244,667 (an anti-microbial composition which involves use of partial or complete substitution of ion-exchangeable metal ion such a silver, copper, zinc and others), U.S. Pat. No. 5,405,644 (an anti-microbial fiber having a silver containing inorganic microbiocide and the silver ion is stated to have been supported by zeolite, among other materials, the purpose being to prevent discoloration).

Various products have been made using anti-microbial fibers. U.S. Pat. No. 5,071,551 discloses a water purifier having a secondary filter downstream of its primary filter for removing microorganisms and antimicrobial means disposed between the two filters. use of an anti-microbial agent for a water purifier.

Japanese Patent No. 6116872 (1994) discloses a suede-like synthetic leather with an anti-microbial agent. It discloses the use of anti-microbial zeolite having an anti-microbial metal ion. It uses two fiber types and includes PET.

U.S. Pat. No. 5,733,949 discloses an anti-microbial adhesive composition for dental use. The composition was made by blending of a polymerizable monomer having alcoholic hydroxy group and water to a dental composition containing an anti-microbial polymerizable monomer and a polymerizable monomer having acidic group, and with a polymerization catalyst. Such composition has capability to improve adhesive strength between the tooth and the restorative material to prevent microbial invasion at the interface and kill microorganisms remaining in the microstructure.

U.S. Pat. No. 5,876,489 discloses a germ-removing filter with a filter substrate and an anti-microbial material dispersedly mixed into the filter substrate. The anti-microbial material is an ion exchange fiber bonded with silver ion. In the ion exchange fiber, silver ions capable of killing living germs through an ion exchange reaction.

U.S. Pat. No. 5,900,258 discloses a method for preventing a microorganism from growing and the breakdown of urea to ammonia on the surface of skin, wall, floor, countertop or wall covering, or in absorbent materials by incorporating an effective amount of naturally-occurring and/or synthetic zeolites. The absorbent materials are diapers, clothing, bedsheets, bedpads, surgical apparel, blankets, filters, filtering aids, wall coverings, countertops, and cutting boards, etc. Use of zeolite preventing bacterial infections and rashes in mammals may compromise cell wall processes including basic transport processes. Zeolites may capture or neutralize electrons and inhibit electron transport through key enzymes of the electron transport chain such as cytochrome oxidase.

U.S. Pat. No. 6,037,057 is for a bi-component fiber in which the cross sectional area of the sheath is less than 28% of the total cross sectional area. It also discloses the use of a slickening agent and use of an anti-microbial agent which is an inert inorganic particle having a first coating with the anti-microbial properties, and a second coating which has protective properties.

One of the disadvantages of some of the prior art is that the anti-microbial additives are organic and many organic materials either act as antibiotics and the bacteria “learns” to go around the compound, or many of them give off dioxins in use.

Also, many such additives are applied topically to the fibers or fabrics and tend to wash off or wear off over time and become ineffective. Also, by washing off the additives are placed into the waste water stream.

Thus, there still exists a need to develop metal-containing anti-microbial agents that do not cause the development of resistant bacterial strains for incorporation into products that are used to make a variety of materials. There also still exists a need for these anti-microbial agents to be resistant to being abraded or washed away, thus maintaining their potency as an integral part of the products into which they are incorporated.

PETG as used herein means an amorphous polyester of terephthalic acid and a mixture of predominately ethylene glycol and a lesser amount of 1,4-cyclohexanedimethanol. It is known that PETG can be used in polycarbonate blends to improve impact strength, transparency, processability, solvent resistance and environmental stress cracking resistance.

Udipi discloses in U.S. Pat. Nos. 5,104,934 and 5,187,228 that polymer blends consisting essentially of PC, PETG and a graft rubber composition, can be useful as thermoplastic injection molding resins.

Chen et al. in U.S. Pat. No. 5,106,897 discloses a method for improving the low temperature impact strength of a thermoplastic polyblend of PETG and SAN with no adverse effect on the polyblends clarity. The polyblends are useful in a wide variety of applications including low temperature applications.

Billovits et al. in U.S. Pat. No. 5,134,201 discloses that miscible blends of a thermoplastic methylol polyester and a linear, saturated polyester or co-polyester of aromatic dicarboxylic acid, such as PETG and PET, have improved clarity and exhibit an enhanced barrier to oxygen relative to PET and PETG.

Batdorf in U.S. Pat. No. 5,268,203 discloses a method of thermoforming thermoplastic substrates wherein an integral coating is formed on the thermoplastic substrate that is resistant to removal of the coating. The coating composition employs, in a solvent base, a pigment and a thermoplastic material compatible with the to-be-coated thermoplastic substrate. The thermoplastic material, in cooperation with the pigment, solvent and other components of the coating composition, are, after coating on the thermoplastic substrate, heated to a thermoforming temperature and the thermoplastic material is intimately fused to the thermoplastic substrate surface.

Ogoe et al. in U.S. Pat. No. 5,525,651 disclose that a blend of polycarbonate and chlorinated polyethylene has a desirable balance of impact and ignition resistance properties, and useful in the production of films, fibers, extruded sheets, multi-layer laminates, and the like.

Hanes in U.S. Pat. No. 5,756,578 discloses that a polymer blend comprising a monovinylarene/conjugated diene black copolymer, an amorphous poly(ethylene terephthalate), e.g. PETG, and a crystalline poly(ethylene terephthalate), e.g. PET, has a combination of good clarity, stiffness and toughness.

Eckart et al. in U.S. Pat. No. 5,958,539 disclose a novel thermoplastic article, typically in the form of sheet material, having a fabric comprising textile fibers embedded therein. The thermoplastic article is obtained by applying heat and pressure to a laminate comprising an upper sheet material, a fabric comprised of textile fibers and a lower sheet material. The upper and lower sheet materials are formed from a co-polyester, e.g. PETG. This thermoplastic article may be used in the construction industry as glazing for windows. One or both surface of the article may be textured during the formation of the articles.

Ellison in U.S. Pat. No. 5,985,079 discloses a flexible composite surfacing film for providing a substrate with desired surface characteristics and a method for producing this film. The film comprises a flexible temporary carrier film and a flexible transparent outer polymer clear coat layer releasably bonded to the temporary carrier film. A pigment base coat layer is adhered to the outer clear coat layer and is visible there through, and a thermo-formable backing layer is adhered to the pigmented base coat layer. The film is produced by extruding a molten transparent thermoplastic polymer and applying the polymer to a flexible temporary carrier thereby forming a continuous thin transparent film. The formed composite may be heated while the transparent thermoplastic polymer film is bonded to the flexible temporary carrier to evaporate the volatile liquid vehicle and form a pigment polymer layer. The heating step also molecularly relaxes the underlying film of transparent thermoplastic polymer to relieve any molecular orientation caused by the extrusion. Ellison also mentions that it is desirable to form the flexible temporary carrier from a material that can withstand the molten temperature of the transparent thermoplastic polymer. The preferred flexible temporary carriers used in his invention are PET and PETG.

Sheet materials for various uses are vulnerable to the seeding of bacteria and fungi from various sources, thus providing hospitable sites for their uninhibited growth. The latter is especially true since, depending upon the end use, they often are used in environments where there is great exposure to microbes and fungi. One example is cafeteria trays. Thus, these materials would benefit from having antibacterial and anti-fungal agents incorporated onto them and/or into them. However, most prior art approaches of providing sheet materials with anti-microbial or anti-fungal agents have limited effect.

A variety of patents relate to anti-microbial materials being added to materials. For example, U.S. Pat. No. 3,959,556 (1976) relates to synthetic fibers that incorporate an anti-microbial agent. U.S. Pat. No. 4,624,679 (1986), mentioned above, uses anti-microbial agents in connection with thermoplastic materials. These materials are formed by mixing polyamide resins, anti-microbial agents, and an antioxidant for reducing the degradation of the anti-microbial agent at the high temperatures necessary for processing.

Several other patents describe anti-microbial materials in which the anti-microbial agent is resistant to being washed away. U.S. Pat. No. 4,919,998 (1990) discloses an anti-microbial material that retains its desirable properties after repeated washings.

However, these materials have two inherent commercial disadvantages. First, while the anti-microbial agents incorporated into them do show some resistance to repeated washings, these agents do leach out of the materials, primarily because they are not physically incorporated into them. In fact, in many cases, the anti-microbial agents are only loosely bound into the material and are relatively easily washed away or naturally abraded away over time.

On the other hand if the agents are buried too deeply in the material or homogeneously distributed they will not contact microbes at all and the economics of usage will be adversely affected.

Second, the anti-microbial agents used in these applications are generally organic substances. The disadvantage of these agents when used as anti-microbial agents is that bacteria can develop a resistance to their action. Thus, one is faced with the emergence of bacterial strains that are no longer affected by these anti-microbial agents which negates the function of these materials.

U.S. Pat. No. 4,923,914 for a Surface-Segregatable, Melt-Extrudable Thermoplastic Composition discloses forming a fiber or film of polymer and an additive in which the additive concentration is greater at the surface. for example when surfactants are added to polymers to impart a special property thereto such as a hydrophilic character to the surface, if the additive is compatible with the polymer there is a uniform concentration of the additive throughout the polymer. In the past such webs have been bloomed to bring the surfactant to the surface. But the surfactant is incompatible at melt-extrusion temperatures. The patentee describes a process for overcoming this problem.

However, the process described has not been very usable with anti-microbial agents. For example, see U.S. Pat. No. 5,280,167 which describes the '914 patent discussed above and states that previous attempts to apply the teachings thereof to the preparation of non-woven webs having anti-microbial activity were not successful. This '167 patent provides for delayed anti-microbial activity in order to delay the segregation characteristic of the '914 patent from occurring. The additive which is used is a siloxane quaternary ammonium salt, an organic material.

While these anti-microbial agents are designed to prevent the development of resistant bacterial strains, the use of metal-containing materials presents the added difficulty of being able to successfully disperse the anti-microbial agents throughout the material. Since these metal-containing compounds exists as fairly large size particles (10 microns and greater), the ability to evenly mix or distribute them is limited. In addition, because of this size problem, these substances must necessarily be applied to the surfaces of materials instead of being incorporated into them. The latter causes the additional disadvantage of making the applied anti-microbial agents relatively labile to washings or abrasion.

Thus, there still exists a need to develop anti-microbial non-woven sheet material and fabrics for various uses that do not cause the development of resistant bacterial strains. There also still exists a need for these filters to have substrates-anti-microbial agent systems that are resistant to being washed away, thus maintaining their potency as an integral part of the filters into which they are incorporated.

U.S. Pat. No. 4,350,732 for reinforcing laminate which issued Sep. 21, 1982 discusses a moldable laminate which could be molded into curved shapes and which is bondable to a carrier surface and which is useful in the making of military boots and the like. The present invention is an improvement.

Institutional furnishings are subject to excessive wear and tear. These furnishings must withstand the constant onslaught of dirt and spills of a variety of substances. They must also stand up to frequent cleanings with industrial strength cleansers. As a result, these furnishings could be made stronger and more resistant by using anti-microbial and anti-fungal agents in their manufacture. The limited prior art approaches of coating fibers and/or fabrics with anti-microbial or anti-fungal materials have had only limited success.

Home furnishings are not subjected to as much wear and tear as institutional furnishings and are usually made of a material which has a softer “feel” and is usually more delicate than those made for institutional use. Therefore, it is difficult to make such materials which will stand up to repeated washings and to wear, particularly when they have been prepared with additives for special properties such as anti-microbial agents.

U.S. Pat. No. 3,983,061 for a process for the permanent finishing of fiber materials, including carpets, discloses an aqueous acid liquid for finishing fiber materials especially dyed carpets to make them anti-static, dirt-repellent, and optionally anti-microbial using a single bath process for finishing dyed textile floor coverings to make provide these characteristics to them. It states that the properties are “permanent” and defines this to mean retaining the properties after a “prolonged” period of wear and tear. However, the anti-microbial properties are not believed to last sufficiently long to be of commercially useful application, and the anti-microbial agent disclosed is organic in nature.

U.S. Pat. No. 4,371,577 for an anti-microbial carpet containing amino acid type surfactant is incorporated into fibrous materials prior to or after fabrication into a carpet using an organic material. The fibrous materials can be polyamide acrylic, polyester or polypropylene fibers. The preparation is accomplished in two manners. The first is that the pile yams, the carpet foundations or the yams for carpet foundation are subjected to the impregnation treatment with a surfactant, and the other is that a carpet fabricated from fibrous materials is impregnated with an organic material.

U.S. Pat. No. 5,762,650 for a biocide plus surfactant for protecting carpets where the dyeing and anti-microbial finishing is performed simultaneously. The anti-microbial agent is an organic material.

While there are known anti-microbial agents which are said to be designed to prevent the development of resistant bacterial strains, the use of metal-containing materials presents the added difficulty of being able to successfully disperse the anti-microbial agents throughout the fibers. Since these metal-containing compounds exist as fairly large size particles (10 microns and greater), the ability to evenly mix or distribute them is limited. In addition, because of this size problem, these substances must necessarily be applied to the fibers instead of being incorporated into them. The latter causes the additional disadvantage of making the applied anti-microbial agents relatively labile to washings.

Thus, there still exists a need to develop fabrics, materials and surfaces substrates for use in home and institutional furnishings which contain metal-containing anti-microbial agents that do not cause the development of resistant bacterial strains for incorporation into fibers that are used to make a variety of fabrics. There also still exists a need for these anti-microbial agents to be resistant to being washed away, thus maintaining their potency as an integral part of the fibers, fabrics, materials, and furnishings into which they are incorporated.

U.S. Pat. No. 5,709,870 (1998), mentioned above, discloses a silver-containing anti-microbial agent that has good affinity to the fiber and is stable to heat and light. The anti-microbial consists of silver bound to carboxymethylcellulose in the amount of 0.01 to 1.0 percent silver by weight that is applied to the fibers.

While these anti-microbial agents are designed to prevent the development of resistant bacterial strains, the use of metal-containing materials presents the added difficulty of being able to successfully disperse the anti-microbial agents throughout the fibers. Since these metal-containing compounds exists as fairly large size particles (10 microns and greater), the ability to evenly mix or distribute them is limited. In addition, because of this size problem, these substances must necessarily be applied to the fibers instead of being incorporated into them. The latter causes the additional disadvantage of making the applied anti-microbial agents relatively labile to washings.

Thus, there still exists a need to develop metal-containing anti-microbial agents that do not cause the development of resistant bacterial strains for incorporation into fibers that are used to make a variety of materials. There also still exists a need for these anti-microbial agents to be resistant to being abraded away, thus maintaining their potency as an integral part of the fibers into which they are incorporated. In the event they are not disposable, they need to be resistant to washings.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide anti-microbial agents that are efficacious and greatly resistant to washing off or wearing off of the product to which they are applied.

It is also an object of the present invention to provide anti-microbial additives that are inorganic.

It is another object of the present invention to provide products in which the anti-microbial agent is applied to certain areas, or has higher concentrations in certain areas, to reduce the amount of the anti-microbial agent which needs to be used and thus lower the cost of such products.

It is a further object of the present invention to provide an anti-microbial agents that can be:

combined with color pigments for coloration to withstand fading;

combined with UV additives to withstand fading and degradation in products exposed to significant UV light;

combined with additives to make the surface of the product hydrophilic or hydrophobic;

combined with additives to make the product flame retardant or flame resistant;

combined with additives to make the product anti-stain; and/or

using pigments with the anti-microbial so that the need for conventional dyeing and disposal of dye materials is avoided.

Thus, the present invention provides a synthetic product comprising high and low levels of various thermoplastic polymers and controlled concentrations of inorganic anti-microbial additives mixed with polymers and selectively placed in the end product for greatest technical effectiveness and cost effectiveness.

The present invention also provides a synthetic anti-microbial product comprising high tenacity polymers e.g. polyesters, polyethylene terephalate (PET) in one portion and hydrolysis resistance polymers in another portion with hydrophilic and anti-microbial additives. In some applications the latter portion can be deliberately made hydrolysis-vulnerable to allow “blooming” and enhanced access to anti-microbial additives in the course of several washings or extended uses.

The various polymers, include but are not limited to, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), PCT, PETG [PET, type G], Co-PET and copolyesters generally, Styrene, polytrimethylene terephalate (PTT)m 3GT, Halar®, polyamide 6 or 6,6, etc. The additives include pigments, hydrophilic or hydrophobic additives, anti-odor additives and anti-microbial/anti-fungal inorganic compounds, such as copper, zinc, tin and silver.

The excellent wetting characteristics of PETG can be used to distribute the anti-microbial additive uniformly within a product. In addition to the zeolite of silver, the PETG could carry other inorganic anti-microbial additives such as copper, zinc, or tin.

In addition to the anti-microbial component, the invention may be used to carry pigments with the PETG to achieve certain colors.

The use of hot water improves the products in that washing the products in hot water opens the pores of the PET and such washed products perform better than unwashed products (this is thought to be due to the removal of spinning/weaving lubricants).

It is a principal object of the present film embodiment to provide such sheet and film materials that meet these needs in a manner consistent with industry specifications, overall durability, and cost-effectiveness.

It is another object of the film and sheet embodiment [present invention] to provide such sheet materials in various forms such as rigid, semi-rigid or flexible and which may be constructed covered with thin films, or not, as desired.

The foregoing objects are met by sheet and film materials of an anti-microbial non-fibrous material such as melted thermoplastic material that has been designed using inorganic silver-containing compounds that allow the formation of both mono- and multi-layer polymeric materials having these anti-microbial agents intermixed within the polymer during material formation.

The anti-microbial will usually be included at and near the surface of a thin layer such as a film. The concentration of the anti-microbial agent can be varied as a gradient using mixing strategies. The concentration of anti-microbial agent within or on the surface of sheet material can also be varied regionally using materials containing varying amounts of anti-microbial agents in conjunction with both natural and synthetic materials having different amounts of anti-microbial agents or even no added anti-microbial agents. A variety of other agents can be added, either by mixing or topically, to color the material and/or to make it resistant to staining, fire, and ultraviolet (UV) light as well as altering its water absorbing qualities. Various polymers, without limitation, can be used to form these fibers. In the context of this invention, anti-microbial refers, but is not limited, to antibacterial and anti-fungal.

The present invention provides several embodiments, one of which relates to the co-extrusion of flat or shaped films or profiles. The product may be a multi-layer construction with the surface layer, on one or both sides, containing zeolite of silver (or other metal such as tin, copper, zinc, etc.).

The product may be a flat film for use in a flat form for counter tops, floors, walls, or molded into shapes such as cafeteria trays, serving dishes, high chair table, refrigerator trays, microwave liners, and luggage.

As a profile the extrusion may be a rain gutter, a screen enclosure, a counter top, hand railing, duct work, sanitary piping, water pipe, gasket materials, around dishwasher, garage door), etc.

The same concept applies to multi-layer injection molded parts. In this case the surface layer may have anti-microbial properties in applications such as telephone handsets, baby bottles, computer keyboards, plastic utensils, and milk bottles.

The choice of particle size of the zeolite is based on the thickness of the film to obtain the best combination of surface area with anchoring in the film. For example, a very thin film of 3 m would be best served with a 1-2 m zeolite, which would have a maximum dimension of 2×1.73 or about 3.5 m.

The inner films could be made of basically any thermoplastic resin, such as; PE, PP, PET, PS, PCT, Polyamide (nylon), Acrylic, PVC, etc. The surface layer(s) could be made of the same polymers plus some low temperature ones such as PETG, Polycaprolactone, EVA, etc.

It is a principal object of the present embodiment to provide such sheet and film materials that meet these needs in a manner consistent with industry specifications, overall durability, and cost-effectiveness.

The foregoing objects are met by sheet and film materials of an anti-microbial non-fibrous material such as melted thermoplastic material that has been designed

Home and institutional furnishings are provided which are made from fibers, yarns, fabrics, materials, and substrates having anti-microbial properties using inorganic silver-containing compounds. The concentration of the anti-microbial agent can be varied within the product-as a gradient using mixing strategies. The concentration of anti-microbial agent within a product can also be varied regionally using varying amounts of anti-microbial agents in conjunction with different amounts of anti-microbial agents or even no added anti-microbial agents. A variety of other agents can be added, either by mixing or topically, to color the product and/or to make it resistant to stains, fire, and ultraviolet (UV) light, as well as altering its water absorbing qualities. Various polymers, can be used. In the context of this invention, anti-microbial refers, but is not limited, to having anti-bacterial and anti-fungal properties.

BRIEF DESCRIPTION OF THE DRAWING

Other objects, features and advantages will be apparent from the following detailed description of preferred embodiments taken in conjunction with the accompanying drawings in which: [0082]
FIG. 1 is a side view of a sheet material having an anti-microbial film layer co-extruded thereon; [0083]
FIG. 2 is a side view of a sheet material having two anti-microbial films extruded thereon, one on each side; [0084]
FIG. 3 is a side view of a further arrangement in which a double sheet material is complete surrounded by an anti-microbial film; [0085]
FIG. 4 is a side view of a shaped sheet material having two anti-microbial films extruded thereon; [0086]
FIG. 5 is an isometric view of a food tray constructed in accordance with the present invention; [0087]
FIG. 6 is a partial sectional view of apparatus for making a multi-layer co-extruded sheet; [0088]
FIG. 7 is a sectional view through the apparatus shown in FIG. 6; [0089]
FIG. 8 is an isometric view of apparatus for making a side-by-side co-extruded sheet; [0090]
FIG. 9 is a cross section through an insole made in accordance with the present invention; [0091]
FIG. 10 is a plan view of the insole of FIG. 9; [0092]
FIG. 11 is a cross section through a laminate for footwear components;[0093]

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

In the United States, all claims concerning anti-microbial and anti-fungal properties must be thoroughly tested to Environmental Protection Agency (EPA) and Food and Drug Administration (FDA) standards before making claims. The anti-microbial herein can be said to “kill bacteria” in that it kills 99.99% (log 4) of bacteria in 24 hours, and “anti-microbial” in that is kills 99.9% (log 3) of bacteria in 24 hours. This is based upon actual test results. Testing, such as by using the shake flask test, has demonstrated that when fibers and fabrics are tested using the anti-microbial system disclosed herein, the number of bacteria on the fibers is reduced by 99.99% or more over a 24-hour period and at least by 99.9%. This testing was performed using several different bacteria, including Pseudomonas aeruginosa, Staphylococcus aereus and Klebsiella pneumoniae. The testing was conducted using both unwashed fibers and fibers that had been washed fifty times to simulate use of the fiber in an application, such as a pillow. The EPA has indicated that products tested using this system may claim “Prohibits Bacteria Growth and Migration Along the Surface of the Product.” The addition of the agent in this system inhibits the growth of mold and mildew or odor-causing bacteria in the fibers. This is a true anti-microbial product. The fibers retain their efficacy after simulated use conditions so that the anti-microbial action lasts the life of the product. [0094]
Sheet Material [0095]
Sheet material as disclosed, for example in pending provisional application Serial 60/180,240 filed Feb. 4, 2000, the contents of which are physically incorporated herein below, in which flat or shaped sheets or films, including wide sheets can be individually extruded or there can be co-extrusion of flat or shaped films or profiles. The product may be a multi-layer construction with the surface layer, on one or both sides, containing zeolite of silver (or other metal such as tin, copper, zinc, etc.). The product may be a flat film for use in a flat form for counter tops, floors, walls, or molded into shapes such as cafeteria trays, shoe insoles, serving dishes, high chair table, refrigerator trays, microwave liners, and luggage. As a profile the extrusion may be a rain gutter, a screen enclosure, a counter top, hand railing, duct work, sanitary piping, water pipe, gasket materials around dishwashers, and the like. The same concept applies to multi-layer injection molded parts. In this case the surface layer may have anti-microbial properties in applications such as telephone handsets, baby bottles, computer keyboards, plastic utensils, milk bottles, and the like. The choice of particle size of the zeolite is based on the thickness of the film to obtain the best combination of surface area with anchoring in the film. For example, a very thin film of 3μ would be best served with a 1-2μ zeolite, which would have a maximum dimension of 2×1.73 or about 3.5μ. The inner films could be made of basically any thermoplastic resin, such as; PE, PP, PET, PS, PCT, Polyamide (nylon), Acrylic, PVC, etc. The surface layer(s) could be made of the same polymers plus some low temperature ones such as PETG, Polycaprolactone, EVA, and the like. Anti-microbial films are used to make sheet materials for a variety of applications in which it is necessary or desirable to reduce bacterial and fungal growth and their resultant odor. An anti-microbial sheet material is made of film which comprises various thermoplastic polymers and additives. The anti-microbial synthetic films can comprise inorganic anti-microbial additives, distributed only in certain areas in order to reduce the amount of the anti-microbial agents being used, and therefore the cost of such films. The anti-microbial additives used in the synthetic film do not wash off over time because they are integrally incorporated into these films, thus their effectiveness is increased and prolonged. The anti-microbial synthetic films comprise high tenacity polymers (e.g. PET) in one component and hydrolysis resistance polymers (e.g. PCT) in another component. The hydrophilic and anti-microbial additives provide a hydrolysis-resistant surface. If desired, fibers may be included and extruded. For example, such fibers could be used to make the two outer layers of the sheet material using sheath/core arrangements so that the anti-microbial agent is only present in the sheath to reduce the amount of anti-microbial agent which is used. [0096]
The present invention provides several embodiments, some of which relate to the co-extrusion of flat or shaped films, sheets or profiles. The product may be a co-extruded multi-layer construction with the surface layer, on one or both sides, containing an inorganic anti-microbial and/or anti-fungal agent. [0097]
The product may be a flat film for use in a flat form for such uses as counter tops, floors, walls, or molded into shapes such as cafeteria trays, serving dishes, high chair tables, refrigerator trays, microwave liners and luggage. [0098]
As a profile the extrusion may be a rain gutter, a screen enclosure, a counter top, hand railing, duct work, sanitary piping , water pipe, and gasket materials around dishwashers and garage doors. [0099]
The same concept applies to multi-layer injection molded parts. In this case the surface layer may have anti-microbial properties in applications such as telephone handsets, baby bottles, computer keyboards, plastic utensils, milk bottles, automotive interior parts, aircraft/bus/train seat and trim parts, and the like. [0100]
When the anti-microbial is zeolite of silver, the choice of particle size of the zeolyte is based on the thickness of the film to obtain the best combination of surface area with anchoring in the film. For example, a very thin film of 3 m would be best served with a 1-2 m zeolite, which would have a maximum cubic dimension of 2×1.73 or about 3.5 m. In this manner the anti-microbial particles are at least partially exposed and are not completely embedded in the thermoplastic material where they would have no anti-microbial effect unless the covering surface were abraded away. [0101]
The inner films or layers can be made of basically any thermoplastic resin, such as; PE, PP, PET, PS, PCT, Polyamide (nylon), Acrylic, PVC, etc. The surface layer(s) can be made of the same polymers plus some low temperature ones such as PETG, Polycaprolactone, EVA, etc. [0102]
Sheet Material Laminates [0103]
FIG. 1 shows one type of multi-layer sheet in accordance with the present invention. The [0104] multi-layer sheet material 66 has a main, thicker support layer 68 and a surface layer 70 which is a thin layer of a thermoplastic material which is sufficiently thin that small particles of anti-microbial agent are contained therein and have portions thereof which are at the surface or just below the surface of the layer. In this way the anti-microbial particles are bonded into the surface layer 70 and therefore remain there for the life of the material or product made from the sheet material and provide anti-microbial properties for the entire time. It is advantageous to have the anti-microbial agent only at the surface since this is the only place where it comes into contact with microbes and fungi and to have the agent in other places in the multi-layer sheet material is wasteful.
Another type of multi-layer sheet construction, which may be used to accomplish the purposes of the present invention is shown in FIG. 2. In this arrangement the [0105] multi-layer sheet material 72 has a main support layer 74 and both surfaces thereof have surface layers 78 and 80, respectively. One or both of the surface layers 78 and 80 have the anti-microbial agent. Layer 74 is a wide sheet of material which may be extruded of thermoplastic material. It can be a rigid material or a flexible material depending upon the end use. The second and third layers of wide sheet material are attached to it by suitable means known in the art or they may be co-extruded as described below in connection with FIGS. 6-8. There is a surface layer having an anti-microbial agent (which may be or include an anti-fungal agent) is attached to both sides of the composite layers. These layers are connected by a suitable means known in the art when they are not co-extruded.
This three layer arrangement may be co-extruded at one time so that the three layers are bonded together immediately after extrusion and while the layers are still hot and prior to quenching. For a discussion of the co-extrusion process, see FIGS. 6 and 7 and the description thereof which appears below. [0106]
There are many uses which may be made of this composite, and the end use is evaluated to determine additional features which are added. For example, if the finished composite of FIG. 1 or FIG. 2 is to be formed into a shape for cafeteria trays or food trays (see FIG. 5), then only one surface layer having the anti-microbial agent is needed and the support layer is rigid to provide rigidity to the tray. The material is hard and smooth so that it may be easily cleaned yet still provide the anti-microbial effect. The food tray is die formed after the sheet is made by the co-extrusion process. [0107]
It is possible to form the three [0108] layer sheet 72 which includes the support layer 74 of at least 10 microns in thickness which is extruded at the same time as a second sheet 78 which becomes a two-layer sheet, the second sheet being 4 microns in thickness and being supported by the first layer. The extruding of both layers is done at the same time and the second sheet 78 is joined to the first sheet 74 before the quenching is complete. If desired a third sheet 80 similar to the second one, 78, can be made at the same time. The second and third sheets may have an anti-microbial agent of the type discussed herein mixed with the thermoplastic material so that the three layer sheet has a thin top layer and a thin bottom layer which possess anti-microbial properties.
FIG. 3 shows a [0109] multi-layer sheet 82 having a first inner layer 84 and a second inner layer 86 with two surface layers 88 and 90. It also includes edge layers 92 and 76, and which is suitable for various purposes. It may be constructed as shown in FIGS. 6 and 7 and as described below.
FIG. 4 shows a [0110] multi-layer sheet 94 which has a shape in the form of a curve and which includes a center support layer 96 and two surface layers 98 and 100.
FIG. 5 shows a [0111] food tray 102 which may be the type which contains food and is purchased in food stores with food packaged therein. This tray includes two basic parts, a bottom 104 and a top 106. The bottom 104 may be of PET which is crystallized in order to provide a firm layer which may support the food products contained therein. After the multi-layer sheet material is made, the food tray parts are formed in dies. This bottom part 104 has a bottom layer 108 and four side- walls 110, 112, 114, and 116. For all the parts of the bottom 104, there is an inner layer 118 of a thin film which is attached to a support layer 122 and this film 118 contains an anti-microbial agent as indicated by the stippling. There are tabs 124 and 125 on the bottom which fit into holes 120 on the top 106. The top is made of a transparent material and is in the amorphous state. The anti-microbial agent prevents the growing of microbes which are killed upon contact with the inner film layer of the bottom of the food tray.
Making Co-Extruded Sheet Material Laminates [0112]
With reference to FIGS. 6 and 7, a suitable die has a funnel-shaped [0113] expansion chamber 128 terminating in a slotted die outlet 128 defined by a pair of spaced die lips. The die has a shallow chamber entrance section 132.
The [0114] feed block 126 comprises a plurality of slotted layer distribution passages 134 in the form of mutually spaced apart slots or openings lying substantially parallel to slotted die outlet 128. The passages extend from an inlet side to an outlet side of the feed block 126.
The feed block further comprises [0115] end encapsulation slots 166 and 158 extending between inlet and outlet sides without intersecting passages 134 and lying substantially perpendicular thereto. Otherwise, slots 166 and 158 may extend along planes converging together from the inlet side to the outlet side. The feed block assembly 152 includes a frame 136 connected to the upstream end of the die in some suitable manner and defining a chamber (not shown) open on opposite sides to facilitate removal and replacement of feed block 126 with an interchangeable feed block designed to accommodate specific resin viscosities, selected polymer matchups, layer thickness changes, layer geometry, etc.
[0116] Frame 136 includes various connectors 138A and 138B to which extruders (not shown) of polymer melts are connected, and to which feed channels or feed lines (also not shown) are likewise connected for feeding the melts to slots 134A-134E, 166 and 158, or to selected ones thereof.
The feed block may be connected in some suitable manner to frame [0117] 136 or may be unconnected thereto.
Apparatus generally designated [0118] 152 is illustrated in FIGS. 6 and 7 as comprising a slit die 140 of mating die halves. A feed block assembly, generally designated 150, is totally integrated into the die as it is inserted within a die cavity 156 open at the upstream end of the die and at opposing sides of the die, shown in FIG. 6. Feed block assembly 150 comprises feed block 126, connectors 138A and 138B and melt feed lines 141A and 141B, respectively, extending from the connector 138A for feeding plastic melt from the extruder to the slotted passages 134A, 134B and 134C, and from the connector 138B for feeding plastic melts from the extruder to the slotted passages 134D and 134E. When an anti-microbial or the like is to be provided in the thinner outer sides of the sheet material, such an agent is added into the melt which is then extruded and fed to feed line 141B and connector 138B to extruding slots 134D and 134E. In the event the edges of the laminated sheet material is to differ from the material fed into feed lines 141A and 141B, a third feed line (not shown) can be connected to slotted passages 166 and 158 of the feed block. If the edges are not to be different the slotted passages 166 and 158 are not or may be omitted from the construction of feed block 126. Thus, the entire feed block assembly 150 can be removed from cavity 156 and replaced by another feed block assembly for a new production cycle.
Feed block [0119] 126 of apparatus 152 can be provided with externally accessible means to control the melt streams of polymer melt passing through the outermost slots 134D and 134E for adjusting the distribution of the outer or skin layers of the skin laminate to be formed. Such control means may be in the form of a restrictor bar 154 extending transversely to the direction of flow of melt through the passages for controlling the width and/or shape of the outermost passage upon manual manipulation of an adjustment screw 146. The restrictor bar may be located in a side cavity 148 of the feed block.
Otherwise, the skin layer control means may be in the form of a driven [0120] wedge 164 mating with a drive wedge 160 connected to a screw drive 142 via flange 162, as more clearly shown in FIG. 7. The wedges may be housed in a suitable side cavity 144, and a turning of screw drive 142 shifts wedge 160 along the screw drive and causes the driven wedge to be shifted transversely relative to the melt flow through the feed block for controlling the distribution of the skin layer flowing through the outer-most passage of the feed block.
[0121] Restrictor bar 154 can be utilized on both sides of the feed block, and the wedge arrangement can likewise be utilized on both sides. Restrictor bar 154 and wedge 164 can have flat melt flow engaging surfaces, or these surfaces can be concavely or convexly shaped or otherwise contoured to control the layer distribution of the skin layers by modifying the outer slots to accommodate differences in melt viscosities, etc.
With this arrangement one or both outer layers may have an anti-microbial agent. If a three-layer arrangement is made it can have a center layer of 10 m and the outer layers may be 4 m. In such an event the particle size may be about 1.5-2 m. If zeolite of silver particles are used and made this size then substantially every particle of zeolite will have at least a portion exposed by projecting through the outer surface of the layer in which it is embedded. [0122]
FIG. 8 shows a [0123] die 168 having a single extrusion slot with three portions, 170, 172 and 174. The sheet which is extruded thereby is shown having a center section 176 and two edge portions 178 and 180. The width of the center portion 176 is the same as the widths of the edge portions together. When the extrusion process takes place die slot portion 170 produces edge portion 178, die slot portion 172 produces center portion 176 and die slot portion 174 produces edge portion 180. The stippling indicates that an anti-microbial and/or an anti-fungal agent has been incorporated into the center portion of the extruded sheet. The extruded sheet is shown having a thickness 182 which is the same throughout, although portions could be of different thickness if this is desired.
Thus FIG. 8 shows a manner of making a co-extrusion multi-layer sheet in which the [0124] edges 178 and 180 of the extruded sheet are different from the center 176 in some respect and if desired, after extrusion and while still having the heat of the extrusion (prior to quenching) the two edge portions 178 and 180 are folded under to provide a layer under the center section. In this manner a two-layer sheet is formed with layer 176 having microbe and fungus killing properties on one side of the two-layer sheet.
If desired, the die and sheet could have only two sections of equal width, in which event one would be folded over the other to form the two-layer sheet with one layer having anti-microbial properties. [0125]
Construction of the Multi-Layer Sheet Material [0126]
Anti-microbial agents can be used in making sheet materials for a variety of applications in which it is necessary or desirable to reduce bacterial and fungal growth and their resultant odor. [0127]
In manufacturing these materials, any of the embodiments described above could be used. Both the strength and resiliency of these materials is important. Any number of shaped designs could be used as appropriate. In some instances, round would be appropriate whereas in other instances rectangular or other shapes, both simple and complicated would be appropriate, all depending upon the use to be made of the material. [0128]
Also, other modifications of the characteristics of these materials beyond that of adding anti-microbial agents, including the addition of agents to increase or decrease hydrophobicity, is useful. In addition, anti-odor additives may be particularly useful in cafeteria or other types of food trays. [0129]
The relatively small size of the preferred anti-microbial agent which is silver-containing zeolite compounds (which can be as small as 2 microns and less) that are used in the manufacturing of the sheet film allow these anti-microbial agents to be incorporated into the thin sheet films instead of being applied to them. Thus, because these anti-microbial agents are an integral part of the film, they are not washed or easily abraded away and the finished articles manufactured from them are able to withstand significant wear and multiple washings while maintaining their anti-microbial effectiveness. In the case of products which are thrown away after use, the resistance to washings is not an important factor. [0130]
Specifically, higher loading of the anti-microbial agents (up to 5 times) is used to more effectively act against fungi. This higher loading may be achieved by using various zeolites followed by heating the film polymer, e.g. PET, to between 180 and 228 degrees Fahrenheit in hot water which allows further metal loading or ion exchange to replace resident metal ions with another ion or mixture of ions. In addition, this would allow the zeolite at or near the surface of the film to be preferentially loaded with the metal ion or mixtures thereof that has the desired biological effect. These methods are particularly useful in reducing costs when expensive metal ions, such as silver, are used in these processes. Also, by adding certain metals, e.g. silver, at this point in the process and not having it present during the high temperature film extrusion process, any yellowing or discoloration due to oxidation of the metal ion or its exposure to sulfur and halogens would be greatly reduced. [0131]
The synthetic films used in the present invention can be made of various polymers and co-polymers, including thermoplastic ones. These polymers include, but are not limited to, polyethylene (PE), polypropylene (PP), poly 1,4 cyclohexylene dimethylene terephthalate (PCT), PET, PET type G (PETG), co-PET, and co-polymers generally. These films can also contain styrene, Halar®, and various polyamides. [0132]
As defined in this invention, anti-microbial means a thousand-fold reduction in bacteria. Thus, the materials and products of this invention are subjected to tests which show a 1000-fold reduction in colony forming units (CFU) of bacteria. To kill bacteria means a ten thousand-fold reduction in bacteria and the materials and products of this invention are capable of a 10,000-fold reduction in CFU of bacteria. [0133]
This level of antibacterial protection is achieved generally by having between 0.1 and 20 percent by weight of an anti-microbial agent incorporated into a multi-layered sheet material. Alternatively, the anti-microbial agent concentration can be reduced to between 0.2 and 6.0 percent in multi-layer sheets in which the anti-microbial agent is only mixed into the outer layer(s) of the multi-layer sheet. This latter configuration allows less anti-microbial compound to be used, thus significantly reducing the cost of manufacture, and thus the cost of the sheet material. [0134]
It is also possible to use these integrated anti-microbial compounds to make sheet materials and products that have a varying distribution of the anti-microbial agent. For example, by varying the concentrations of the anti-microbial agent during mixture with the film-forming polymers, films having varying anti-microbial content can be formed which can then be added in varying amounts to form sheet materials having varying concentrations of anti-microbial agents. In addition, the amount of anti-microbial present in the film itself can be varied, either lengthwise or in cross-section. Similarly, higher and lower concentrations of these anti-microbial agents in the overall films can be achieved by using multi-layered sheets in which, for example, the anti-microbial agent is present only in an outer layer section, thus significantly reducing manufacturing and selling costs. Any of the above manufactured anti-microbial films can be used with films that do not contain anti-microbial agents such that sheets and products can be made having overall and localized variations in concentrations of anti-microbial agents. [0135]
Color pigments can be added to these anti-microbial films in order to provide a pleasing coloration for such sheet materials when the ultimate products are purchased by consumers. Similarly to the above anti-microbial agents, these pigment materials can be added such that the pigments are encapsulated in the polymers that are used to make these sheet materials. By using this method of coloring the films, materials for end use products made from these colored films are color-fast and do not leach out their color during washing, thus significantly reducing fading during use and washing. In addition, since the need for conventional dyeing techniques can be reduced or eliminated, the disposal of environmentally damaging dye materials is avoided. This, in and of itself, can reduce the costs of manufacturing finished colored sheet materials due to the elimination of the manufacturing infrastructure and associated personnel needed to process residual dye effluents. [0136]
In a similar fashion to anti-microbial agents and color pigments, a variety of other additives that are used for various purposes can be combined with the polymers during or after film formation and extrusion. For example, additives that protect against damage from UV light can be added to the film polymer or coated onto it so that the sheet materials or end use products formed are resistant to the fading of colors and UV damage generally, although this is not a factor for all products. Both flame-resistant and -retardant agents can also be added to the films of this invention in a manner similar to that described for UV protecting agents. In this way, the sheet materials formed can be made resistant to fire. [0137]
In addition, the films can be made either hydrophilic or hydrophobic as desired by mixing other agents into the film polymers or applying them to the film surface. By modifying the wetability characteristics of the films, they can be made more useful for various applications. For example, hydrophilic films are effective in applications in which one wants the anti-microbial sheet material to more easily absorb water, such as when the material is designed to be used in humid conditions. Alternatively, hydrophobic films are effective in applications in which one wants to avoid the absorption of such solutions. [0138]
The anti-microbial agents can also be added to low-melt polymer films that can be activated and melted during sheet material production by raising the temperature, thus spreading the anti-microbial agents throughout the material when the low-melt films melt and coat the surface of the supporting layer. By varying the amount of anti-microbial-containing low-melt film regionally and/or by varying the amount of anti-microbial agent in these low-melt films, a sheet material can be produced that has a purposely designed regional variation in anti-microbial effectiveness throughout. [0139]
Specifically, the latter situation can be achieved by using an amorphous binding film such as PETG, which can be blended to form various types of sheet materials. After heat activation, the PETG melts, wetting the surface of the surrounding films adjacent surface or surfaces. In this way, solidified PETG forms and binds the layers together while spreading the anti-microbial agent throughout the surfaces. Because of the excellent wetting characteristics of PETG, the anti-microbial agent can be uniformly distributed throughout the material. These methods of activating PETG may also be used to additionally distribute other additives described above throughout the finished materials. [0140]
The anti-microbial additives used are metals such as copper, zinc, tin, and silver as part of an inorganic matrix. The best results can be obtained using a zeolite of silver dispersed in a PE,PP, PS, Nylon, PET, or PBT carrier. These additives can be added directly to the melt without a carrier. The total anti-microbial additive concentration ranges from 0.2 to 6.0 percent by weight of fiber depending on performance requirements. Other additives which can be incorporated include one or more of UV stabilizers at 0.1 to 5.0 percent; fire-retardant additives at 0.1 to 5.0 percent; pigments at 0.1 to 5.0 percent; hydrophilic additives at 0.2 to 5.0 percent; and hydrophobic additives at 0.2 to 5.0 percent. [0141]
Another configuration of the present invention is a multi-layered film in which the components are the same polymers and additives as described above. In this embodiment one layer is used for strength another layer is used as a binder that contains inserted additives. Variants of this such as three and four layered products, and even up to ten layered products with the outer two layers carrying the anti-microbial agent can also be made. [0142]
It should be understood that the nominal binder or binder component can also be a strength enhancer in some combinations. It will also be understood that other variants including but not limited to combinations, can be made. For example, a first extrusion could produce intermediate film products and such products could be put together with each other or with separate layers. [0143]
Another embodiment is a grouping of layers used to practice the invention. One configuration uses PET or other high tenacity polymer at between 20 and 80 percent by weight. Poly 1,4 cyclohexylene dimethylene terephthalate (PCT) or other hydrolysis resistant polymer is used in another layer at a ratio of 80 to 20 percent. One layer is designed to provide the strength and the modulus can be varied to create a high modulus layer, or a low modulus layer, or anywhere in between. The use of PCT in the a layer provides a hydrolysis resistant surface and resistance to long term washings in boiling water and strong soaps. The multi-layer anti-microbial/anti-fungal synthetic layers can be produced in a wide range of thicknesses. [0144]
Additives include pigments, compounds to create a hydrophilic surface, and anti-microbial, anti-fungal, and anti-odor agents. The pigment additives provide uniform colors that do not fade significantly over long-term use and washing, unlike dyes, because these additives are integrally mixed within the polymer making up the sheet or film. In addition, compounds may be used which create a hydrophilic surface. The anti-microbial, anti-fungal and anti-odor additives can be varied, both in types and amounts, depending on the final product desired. [0145]
One layer made from low temperature polymers with a melting or softening temperature below 200 degrees C., such as PETG, PE, PP, co-PET, or amorphous PET, may be used as binder carrier for anti-microbial additives. [0146]
The anti-microbial additives are inorganic compounds of metals such as copper, tin, zinc, silver, etc. The preferred compound is a zeolite of silver dispersed in PE, PET, or PBT before being added to the layer. The additives could be added directly to the primary polymer with pre-dispersion. The total active ingredients range from 0.1 to 20 percent by sheet weight. [0147]
Thus, an anti-microbial sheet material can be produced that is able to withstand significant wear and washings and maintain its effectiveness. [0148]
It will now be apparent to those skilled in the art that other embodiments, improvements, details, and uses can be made consistent with the letter and spirit of the foregoing disclosure and within the scope of this patent, which is limited only by the following claims, construed in accordance with the patent law, including the doctrine of equivalents.[0149]

Claims

What is claimed is:

1. An anti-microbial product in the form of a wide plastic sheet, comprising:

a first layer of a plastic polymer matrix and an anti-microbial/anti-fungal inorganic additive dispersed therein, the thickness of the layer being approximately 1.5 to 3 times the nominal particle size of the additive; and

at least one further plastic polymer layer adjacent to and providing support to the first layer.

2. The product of claim 1, wherein the additive is one selected from the group consisting of copper, zinc, tin and silver.

3. The product of claim 2, wherein the additive is a zeolite of silver.

4. The product of claim 1, wherein the additive comprises approximately 1 micron cubes and the first layer thickness is approximately 2 microns thick.

5. The product of claim 1, wherein the at least one further layer has dispersed therein a second additive selected from the group consisting of pigments, anti-odor compounds, UV resistant, anti-stain, flame retardant or flame resistant, hydrophilic, and hydrophobic materials.

6. The product of claim 5, wherein the second additive is a hydrolysis resistant polymer providing resistance to long term washings in boiling water and strong soaps.

7. The product of claim 5, wherein the second additive is a pigment providing uniform colors that do not fade significantly over long-term use and washing.

8. The product of claim 1, the first layer being sufficiently dimensioned such that particles of the additive are held close to the outer surface of the first layer while affording resistance to removal therefrom under production and usage conditions of the product.

9. The product of claim 1, wherein the at least one further layer comprises:

at least one further layer of a plastic polymer matrix and an anti-microbial/anti-fungal inorganic additive dispersed therein; and

a thicker support layer disposed adjacent to and between the first layer and the at least one further layer of plastic polymer matrix and additive dispersed therein.

10. The product of claim 1, further comprising:

at least one edge layer of a plastic polymer matrix and an anti-microbial/anti-fungal inorganic additive dispersed therein, the edge layer adjacent to both the first layer and the at least one further layer.

11. The product of claim 1, wherein the plastic polymer of the first layer is selected from the group consisting of polyolefin, polyethylene, polypropylene, poly 1,4 cyclohexylene dimethylene terephthalate, PETG, co-PET, Styrene, Halar®, PTT, 3GT, polyamide, polycaprolactone, PET, Polycarbonate, PVC, and EVA.

12. The product of claim 1, wherein the plastic polymer of the at least one further layer is comprised of a thermoplastic resin selected from the group consisting of polyethylene, polypropylene, poly 1,4 cyclohexylene dimethylene terephthalate, PET, PETG, co-PET, Styrene, Halar®, PTT, 3GT, polyamide, acrylic, PET, Polycarbonate, PVC, and an ionomer, EVA or styrene stiffened ionomer, and an impact resistant strength layer of nonwoven material.

13. The product of claim 1, wherein the concentration of the additive varies as a gradient within a section of the first layer.

14. The product of claim 1, wherein the concentration of the additive varies regionally within a section of the first layer.

15. The product of claim 1, formed as a flat film.

16. The product of claim 15, consisting of part of work surface, floor, or wall.

17. The product of claim 1, formed as an article exhibiting a rigid, shaped contour.

18. The product of claim 17, consisting of part of a food storing, conveying or serving article. consisting in part of an article for storing or conveying clothing or personal items.

19. The product of claim 1, formed as a profiled article wherein the additive is on the inner or outer surface of the profile.

20. The product of claim 19, selected from one of piping, tubing, and gutters.

21. The product of claim 19, consisting of part of a household or industrial appliance, fixture or utility.

22. The product of claim 1, formed as an injection molded article.

23. The product of claim 22, consisting of part of a hand-held device or utensil.

24. An anti-microbial product in the form of a wide plastic sheet, comprising:

a first layer of a plastic polymer matrix and an anti-microbial/anti-fungal inorganic additive dispersed therein, the thickness of the layer being sufficiently thin such that substantially all particles of the additive are held close to the outer surface of the first layer while affording resistance to removal therefrom under production and usage conditions of the product; and

25. An anti-microbial product in the form of a wide plastic sheet, comprising:

a first layer of a plastic polymer matrix and an anti-microbial/anti-fungal inorganic additive dispersed therein, the thickness of the layer being sufficiently thin such that substantially all particles of the additive have portions available at the outer surface of the first layer; and

26. An anti-microbial product in the form of a wide plastic sheet, comprising:

a first layer of a plastic polymer matrix and an anti-microbial/anti-fungal inorganic additive dispersed therein, the thickness of the layer being less than the maximum dimension of the particles of the additive; and