Novel, quick, and reliable detection methods for determining the presence and/or authenticity of optical and/or audio disc articles (such as compact discs, digital video discs, CD-ROM discs, and the like) when present within a holding container are provided. Specific methods of utilizing particular transparent cases are encompassed within this invention. Specific methods of utilizing particular transparent cases are thus also encompassed within this invention as are navel storage unit configurations to maximize the benefits of the transparent properties thereof.

This invention relates to novel, quick, and reliable detection methods for determining the authenticity of optical and/or audio disc articles (such as compact discs, digital video discs, CD-ROM discs, and the like). Such a method basically entails the incorporation of an identifier or marking means within the edges of target optical discs or within any other portion of a target disc such that exposure to non-visible light sources will provide the desired identification upon irradiation or detection of the marking means therein. Such an identifier or marking agent thus may be utilized in conjunction with a transparent holding case whereby the optical discs may be exposed through the transparent walls thereof to permit detection of counterfeit or authentic discs without requiring opening of the case itself. Such a method may also be utilized for discs that are removed from or have not been placed and sealed within such a case as well. Specific methods of utilizing particular transparent cases are thus also encompassed within this invention as are novel storage unit configurations to maximize the benefits of the transparent properties thereof.
Optical data storage discs, such as compact discs (CDs), digital video discs (DVDs), and compact discs having read-only memory (CD-ROMs), have been utilized within the entertainment and computer field for a number of years, with DVDs recently entering the market with much higher amounts of available encoded information for more impressive video results. Such discs generally comprise a layer of plastic material, on one side of which is formed a micro-relief pattern in the form of indentations which comprise an encoded information signal. This information-containing side exhibiting such a micro-relief pattern is then provided with a lacquer-protected metallized reflective layer to permit reading via a laser sensor. DVDs may contain more than one such layer of micro-relief patterns thus providing increased amount of information. Such DVDs exhibit several formats but always comprise two substrates, each formed with at least one information layer, that are secured to one another. Furthermore, the lacquered portion of the disc, generally being solely on one side, usually is provided with visible printed information for identification, informational, and/or aesthetic purposes to the user. Standard and particular production methods for such discs are disclosed within such documents as U.S. Pat. No. 6,165,391 and European Patent EP 0608358B1 (including the production of discs including holographic images embossed in the lacquer forming the protective layer for the metallized surface in order for the micro-relief pattern to define such an holographic image).
Such optical discs are normally formed from polycarbonate material which is injected into an injection molding machine in which a stamper is present, the stamper forming the pattern of indentations in the subsequently formed disc to provide the encoded signal. Other techniques utilize compression molding with a specific mold to provide the encoded signals therein.
The discs may thus include certain holographic images on the surface as well as different additives within the plastic layer, all not detrimental to the operation of the target disc itself. The periphery of the disc (which is normally produced in circular configuration) is thus available for utilization of any number of identification purposes without affecting the sound or vision quality of the encoded information therein.
Furthermore, storage units for such discs have predominately been either polystyrene in nature (for CDs and CD-ROMs) or black (and thus opaque) polypropylene (for DVDs). Polystyrene is generally very clear and has become commonplace in terms of CD and CD-ROM storage; however, such material has proven to be less than reliable in terms of long-term usage. Polystyrene is generally susceptible to breakage easily, requires a two piece case to provide a hinge, and is more expensive than polyolefins. Opaque polypropylene prevents the ability to view the actual disc prior to opening of the unit itself. Polypropylene withstands certain forces better than polystyrene (such as accidental drops, colliding with solid objects, etc.), and is cheaper than such an expensive material. Furthermore, transparent polypropylene has been utilized to a certain degree as well to reduce costs in other ways. For example, DVDs generally include an attached sleeve to the target storage unit of transparent thin film in order to place an identifying publication therein. Such a thin film sleeve increases costs to such a degree that certain storage unit producers have noted the ability to remove the need for such a costly thin film sleeve and move the published identification papers within the storage unit itself. Thus, with sufficient transparency, the identifying publications can be viewed without opening the box itself.
Unfortunately, even with such a development in storage unit design and production, there has been a lack of maximization of such a benefit. In the past, booklets of limited size have been produced for informational purposes for the user. Such booklets were placed within the storage unit but normally required removal from the storage unit itself prior to reading. Such booklets also cost a great deal of money to produce and pack. There thus exists the need to maximize the benefits of having the full published information documentation within the inside of the target disc storage unit. To date, for example, there still exists a standard configuration wherein the discs as stored remain within the storage unit and thus act as obstacles to reading the provided printed information literature accompanying the disc itself. To date, there has been no discussion or fair suggestion on how best to maximize such a limited design in order to maximize the benefits of utilizing transparent polyolefin storage unit materials themselves.
Additionally, counterfeit audio and/or optical discs are an enormous problem within the pertinent industries. In fact, billions of dollars a year are lost to the respective recording industries due to forged or counterfeited articles. Combating such a problem has proven extremely difficult as the appearance of such counterfeit discs are generally the same as those of authentic quality. Thus, proving authenticity is generally difficult, if not impossible. Past attempts at preventing or detecting such counterfeit discs have included technologies such as anti-copying/encryption technologies, digital signatures, watermarks, and the like, embedded within the disc""s content. However, these technologies have proved ineffective as decoders have been easy to develop for encryption and identifiers have been easy to copy. Therefore, stopping such counterfeit articles is quite elusive, particularly at the customs (importation) or customer level. A simplified method of facilitating such needed detection of counterfeit articles is thus of utmost importance to these industries. Of particular interest is the ability to provide such detection when discs are shrink-wrapped together, prior to placement within ultimate storage units, as well as upon placement within such storage units (which are also generally shrink-wrapped for consumer purchase) in a manner that detection can be made without having to open the storage unit itself (and thus provides an easy method for the distributor to determine disc authenticity without affecting the value of the pre-packaged disc). Thus, such a desirable simplified detection method has not been accorded these particular industries to date.
It is thus an object of this invention to provide a manner of detecting counterfeit optical discs either while removed from any packaging, while present within a closed storage unit, or while present in a shrink-wrapped package of multiple discs. Another object of this invention is to provide a detection method for the authenticity of optical discs through the exposure of such discs to light within the non-visible spectrum and viewing the resultant appearance of the edges of such discs. Yet another object of the invention is to provide a simultaneous manner of efficient storage of discs and improved access to provided informational literature accompanying such discs.
Accordingly, this invention encompasses a method of determining the authenticity and/or counterfeit status of at least one optical disc comprising the steps of
(a) providing at least one optical disc including at least one authenticity identifier selected from the group consisting of at least one iridescing compound, at least one iridescing pattern, and any combinations thereof, wherein said identifier is identifiable at least along the periphery of said disc;
(b) exposing said disc to a source of iridescent light within the non-visible spectrum; and
(c) viewing the periphery of said at least one disc for the presence of said identifier; wherein if said identifier is present, then said disc is considered authentic, and wherein if said identifier is not present, then said disc is not considered authentic. Also encompassed within this invention is a method for determining the authenticity and/or counterfeit status of at least one optical disc present within a closed transparent storage unit, said method comprising the steps of
(a) providing at least one optical disc including at least one identification image thereon; and
(b) viewing said optical disc within said closed transparent storage unit for the presence of said at least one identification image;
wherein if said at least one holographic is viewed, then said disc is considered authentic, and wherein if said at least holographic image is not present, then said disc is not considered authentic. Further encompassed within this invention is a method of determining the authenticity and/or counterfeit status of at least one optical disc present within a closed transparent storage unit, said method comprising the steps of
(a) providing an optical disc within said closed transparent storage unit, said optical disc including at least one authenticity identifier selected from the group consisting of at least one iridescing compound, at least one iridescing pattern, at least one identifying pattern, and any combinations thereof, wherein said identifier is identifiable at least along the periphery of said disc;
(b) exposing said storage unit disc to a source of iridescent light within the nonvisible spectrum; and
(c) viewing the periphery of said at least one disc while still within said closed storage unit for the presence of said identifier; wherein if said identifier is present, then said disc is considered authentic, and wherein if said identifier is not present, then said disc is not considered authentic. Lastly, this invention also encompasses a polyolefin-containing storage unit including at least one peripheral edge and including at least one rosette for optical disc storage, said at least one rosette being present on an arm which is permanently or temporarily attached to said at least one peripheral edge via a movable hinge, wherein said optical disc may be maneuvered outside of said storage unit while simultaneously being attached to said rosette which in turn remains attached to said arm while said arm remains attached to said at least one peripheral edge of said storage unit.
As it pertains to this invention, the term xe2x80x9cauthenticity identifierxe2x80x9d is intended to encompass any type of additive, whether integrated within the target disc or adhered to the surface of the target disc, that can be illuminated, preferably through utilization of a light source within the non-visible spectrum (such as, without limitation, infrared light, infrared laser, ultraviolet light, ultraviolet laser, and the like). Preferably, such an authenticity identifier is provided wherein the resultant detection thereof is noted through visible realization of a unique signal. Thus, bar-coding, iridescent compounds, patterns of barcodes intermixed with iridescent compounds, patterns of iridescent compounds, and the like, are possible, non-limiting available manners of providing such an authenticity identifier thereon or therein the target optical disc.
More preferably, such an authenticity identifier is present within the plastic layer of the target optical, and most preferably added thereto in such a manner as to permit identification of such an additive at the surface of the periphery of the target optical disc itself. A distinct problem facing the optical disc industries concerns the fact that individual discs are counterfeited readily and may be passed off as authentic during importation through customs departments. Generally, prior to packing within desired storage units, such discs are produced in large quantities and are shrink-wrapped hundreds at a time for shipping. Such shrink-wrap is generally transparent in nature as well and thus permits ease in identification of an authenticity identifier at the periphery of each individual disc when present in shrink-wrapped form prior to packing within storage units. In such a manner, the shrink-wrapped discs may be illuminated and analyzed for the presence of the needed authenticity identifier. Such a method thus facilitates review by the proper importation customs officials in order to prevent unlawful shipping of counterfeit articles.
Such a periphery configuration also facilitates authentication of storage unit-packed optical discs, primarily those packed within transparent cases. Generally, the information literature accompanying the disc(s) is sufficiently large that it resides within the entire space provided by both halves of the storage unit itself. In such manner, the only open space remaining for easy viewing of the target disc(s) is only the peripheral edge(s) thereof through the transparent material. The storage unit must thus exhibit a proper level of transparency to permit illumination of the disc periphery therein for such an analysis. However, although not required, the design of the storage unit may be improved to the degree that there is substantially no obstacle to illumination and thus analysis of the optical disc therein other than the plastic material of the storage unit itself. For instance, with common polypropylene cases, a living hinge is utilized to provide a completely (or at least substantially) symmetric storage unit that opens easily to provide two, again, substantially, symmetric halves. In such a manner, storage unit, when in closed position, exhibits partition lines that may hinder the view of the target disc""s peripheral edges. Thus, a different design can be employed to maximize viewing of the illuminated disc peripheral edges wherein three edges of the storage unit do not include partitions therein and are free from any obstacles to peripheral edge viewing. Thus, the storage unit design may be asymmetric in configuration with a living hinge employed (for preferred transparent polypropropylene) on a top flap that may be removably attached to the remaining portions of the storage unit such that the stored disc is placed within the bottom portion thereof the sides of which do not exhibit any impedance to viewing. Such a design is noted below in the drawings. As a result of any manner of detection in such a manner, the disc contained therein can be analyzed prior to opening and/or removal, thereby preventing a loss in value of the target disc or at least providing a much simpler method of determining authenticity for the distributor, exhibitor, and/or consumer.
The utilization of polyolefin (preferably transparent polypropylene) aids in removing the problems associated with polystyrene jewel boxes as well. Generally, such polystyrene boxes are brittle and, as noted above, highly susceptible to breakage, both within the flap portions of the target box, as well as at the detachable hinge portion(s). In addition, such boxes generally only permit easy viewing of the target disc therein at one side. Clarity is an important characteristic of polystyrene; however, one edge of the jewel box is usually covered by the title of the work provided within the disc itself and two others are roughened such that viewing through such a side is nearly impossible. With the preferred transparent polypropylene storage units of this inventive method, the detection possibilities are increased to three sides of the target storage unit, easily. Although polystyrene is not preferred within this inventive method, of course, since it does provide a certain degree of ability to view a peripheral edge of the target disc, such a material may also be utilized.
Holographic images have been produced within the micro-relief pattern(s) of optical discs in the protective lacquer in order to provide authentication or anti-counterfeiting techniques. In the past, however, such images required first removing the target disc from its storage unit prior to viewing such an anti-counterfeit marking device. Thus, the ability to provide a simpler method of counterfeit detection via transparent storage unit materials, and configuration of the particular storage unit itself, has not been previously investigated. With such a transparent storage unit, the aforementioned benefits of moving the identification literature within the case provides some difficulty in determining proper views of the authenticity image (herein defined as a holographic image, a bar-code, or other like imaging effect that indicates uniqueness of source). If the literature is too large in size and thus only permits viewing at the peripheral edges (as with the other preferred embodiment noted above), then either openings may be provided in the literature for proper viewing of the authenticity image at specified areas of the target disc, or the authenticity image may also be placed on the peripheral edges for proper viewing and analysis by the target audience.
The transparency of the storage unit is of utmost importance for at least one preferred method of authenticity detection. In such a manner, the ability to determine counterfeit discs while the storage unit is either closed, sealed, or both, is not only facilitated, but also permitted. With promotional literature material utilized, either within a sleeve, or placed within the storage unit itself, generally such paper material is placed in such a way as to prevent easy view of the surface of the target disc. Thus, there is a need to either provide a cut-out pattern within the promotional material or smaller material in general, to permit viewing of the surface of the target disc, unless viewing of the peripheral edges is accessible and easier. The transparency of the storage unit material thus accords the ability to actually view either the surface or the peripheral edges without removing the target disc from such a case.
For this purpose, polypropylene is most highly desired, in particular clarified polypropylene (cPP). Any standard clarifying agent may be utilized for this purpose, however, highly preferred are those of the substituted benzylidene sorbitol type, most highly preferred being 3,4-dimethyldibenzylidene sorbitol (available from Milliken and Company under the tradename MILLAD(copyright) 3988 (MILLAD(copyright) 3940 may also be utilized; however, due to plate-out and organoleptic issues, such an additive is not as highly desired for such a purpose). material in the reaction. Such an additive is indicated within U.S. Pat. No. 5,731,474 to Scrivens et al., for example, and is generally added to target polypropylene in an amount of from about 0.01 to about 2 percent by weight, preferably about 0.1 to about 1 percent by weight, based upon the total weight of the composition may be provided.
The polyolefin polymers of the present invention may include aliphatic polyolefins and copolymers made from at least one aliphatic olefin and one or more ethylenically unsaturated comonomers. Generally, the comonomers, if present, constitute a minor amount, e.g., about 10 percent or less or even about 5 percent or less, of the entire polyolefin, based upon the total weight of the polyolefin. Such comonomers may serve to assist in clarity improvement of the polyolefin, or they may function to improve other properties of the polymer. Examples include acrylic acid and vinyl acetate, etc. Examples of olefin polymers whose transparency can be improved conveniently according to the present invention are polymers and copolymers of aliphatic monoolefins containing 2 to about 6 carbon atoms which have an average molecular weight of from about 10,000 to about 2,000,000, preferably from about 30,000 to about 300,000, such as polyethylene, linear low density polyethylene, polypropylene, crystalline ethylenepropylene copolymer, poly(1-butene), 1-hexene, 1-octene, vinyl cyclohexane, and polymethylpentene. The polyolefins of the present invention may be described as basically linear, regular polymers that may optionally contain side chains such as are found, for instance, in conventional, low density polyethylene.
The preferred polypropylene composition can be obtained by adding a specific amount of the substituted dibenzylidene sorbitol directly to the polypropylene (or copolymer), and merely mixing them by an suitable means. Alternatively, a concentrate containing as much as about 20 percent by weight of the additive in a polypropylene masterbatch may be prepared and be subsequently mixed with the resin. Furthermore, the clarifying additive (and other additives) may be present in any type of standard polyolefin additive form, including, without limitation, powder, prill, agglomerate, liquid suspension, and the like, particularly comprising dispersion aids such as polyolefin (e.g., polyethylene) waxes, stearate esters of glycerin, montan waxes, mineral oil, and the like. Basically, any form may be exhibited by such a combination or composition including such combination made from blending, agglomeration, compaction, and/or extrusion.
Other additives such as a transparent coloring agent or plasticizers (e.g., dioctyl phthalate, dibutyl phthalate, dioctyl sebacate, mineral oil, or dioctyl adipate), can be added to the composition of the present invention so long as they do not adversely affect the improvement of transparency of the product. It has been found that plasticizers such as those exemplified above may in fact aid in the improvement of the transparency by the diacetal. In particular, it is further contemplated that certain organoleptic improvement additives be added for the purpose of reducing the migration of degraded benzaldehydes from reaching the surface of the desired article. The term xe2x80x9corganoleptic improvement additivexe2x80x9d is intended to encompass such compounds and formulations as antioxidants (to prevent degradation of both the polyolefin and possibly the target alditol derivatives present within such polyolefin), acid neutralizers (to prevent the ability of appreciable amounts of residual acids from attacking the alditol derivatives), and benzaldehyde scavengers (such as hydrazides, hydrazines, and the like, to prevent the migration of foul tasting and smelling benzaldehydes to the target polyolefin surface). Such compounds and formulations can be added in any amounts in order to provide such organoleptic improvements as needed. However, the amounts should not appreciably affect the haze results for the target polyolefin itself. Thus, lower amounts on the order of from about 20 ppm to about 2,000 ppm of the total polyolefin component are desired.
Polyolefin Formation and Testing
Transparent polypropylene optical disc storage units were produced comprising DMDBS clarifying agents sample random copolymer polypropylene (RCP) resins, as noted below. The polypropylene was produced dry blended in a Welex mixer at xcx9c2000 rpm, extruded through a single screw extruder at 400-450xc2x0 F., and pelletized. Accordingly, batches of target polypropylene were produced in accordance with the following table:
The base resin (random copolymer, hereinafter xe2x80x9cRCPxe2x80x9d) and all additives were weighed and then blended in a Welex mixer for 1 minute at about 1600 rpm. All samples were then melt compounded on a Killion single screw extruder at a ramped temperature from about 204xc2x0 to 232xc2x0 C. through four heating zones. The melt temperature upon exit of the extruder die was about 246xc2x0 C. The screw had a diameter of 2.54 cm and a length/diameter ratio of 24:1. Upon melting the molten polymer was filtered through a 60 mesh (250 micron) screen. The target storage units of this polypropylene material were then made through extrusion into an Arburg 25 ton injection molder with the proper mold configuration. The molder was set at a temperature anywhere between 190 and 260xc2x0 C., with a range of 190 to 240xc2x0 C. preferred, most preferably from about 200 to 230xc2x0 C. (for the Tables below, the standard temperature was 220; a # denotes a temperature 210, a {circumflex over ( )} denotes a temperature of 200, and a @ denotes a temperature of 230). The storage units had dimensions of about 200 mmxc3x97200 mmxc3x971.27 mm, and were made in a mold having a mirror finish. The mold cooling circulating water was controlled at a temperature of about 25xc2x0 C.
The haze values were measured by ASTM Standard Test Method D1003-61 xe2x80x9cStandard Test Method for Haze and Luminous Transmittance of Transparent Plasticsxe2x80x9d. using a BYK Gardner XL-211 Hazemeter. Nucleation capabilities were measured as polymer recrystallization temperatures (which indicate the rate of polymer formation provided by the presence of the nucleating additive) by melting the target plaques, cooling the plaques at a rate of about 20xc2x0 C./minute, and recording the temperature at which polymer reformation occurs. The resultant haze of the product storage units were about 8.0%, a level of sufficient transparency to permit illumination of the optical discs stored therein for authenticity detection in accordance with the inventive methods.
The optical discs themselves may be of any standard composition, wherein at least one plastic layer is coated with at least one information layer, which is further coated with at least one metallized layer, and which is further coated with a lacquer layer. Preferably, the plastic layer is of a material having some compressibility, such as PERSPEX(copyright) (polymethyl methacrylate, or PUMA) and has a thickness between 5 mm and 20 mm.
The metal layer is preferably nickel, although any other reflective metal may be utilized. The lacquer is preferably a methacrylate. The general production methods are as noted above within U.S. Pat. No. 6,165,391, herein entirely incorporated by reference.

Optical disc storage containers that facilitate detection of the presence of optical and/or audio discs stored therein


A gas transport and pressurization system, including a static valve, a compartment concentrically arranged around the static valve, a dynamic valve axially displaceable relative to the static valve, and a crankshaft connected to the dynamic valve, wherein gas from a ground gas well flows through the compartment, the dynamic valve, and the static valve to a gas outlet.

Natural gas or fossil gas, or sometimes called just gas, is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, or helium. It is formed when layers of decomposing plant and animal matter are exposed to intense heat and pressure under the surface of the Earth over millions of years. The energy that the plants originally obtained from the sun is stored in the form of chemical bonds in the gas. Natural gas is a fossil fuel. Natural gas is sometimes informally referred to simply as "gas," especially when it is being compared to other energy sources, such as oil or coal. However, it is not to be confused with gasoline, which is often shortened in colloquial usage to "gas," especially in North America.
Natural gas is a non-renewable hydrocarbon used as a source of energy for heating, cooking, and electricity generation. It is also used as a fuel for vehicles and as a chemical feedstock in the manufacture of plastics and other commercially important organic chemicals.
The mining and consumption of natural gas is a major and growing driver of climate change. It is a potent greenhouse gas itself when released into the atmosphere, and creates carbon dioxide during oxidation. Natural gas can be efficiently burned to generate heat and electricity; emitting less waste and toxins at the point of use relative to other fossil and biomass fuels. However, gas venting and flaring, along with unintended fugitive emissions throughout the supply chain, can result in a similar carbon footprint overall.
Natural gas is found in deep underground rock formations or associated with other hydrocarbon reservoirs in coal beds and as methane clathrates. Petroleum is another resource and fossil fuel found close to and with natural gas. Most natural gas was created over time by two mechanisms: biogenic and thermogenic. Biogenic gas is created by methanogenic organisms in marshes, bogs, landfills, and shallow sediments. Deeper in the earth, at greater temperature and pressure, thermogenic gas is created from buried organic material.
In petroleum production, gas is sometimes burned as flare gas. Before natural gas can be used as a fuel, most, but not all, must be processed to remove impurities, including water, to meet the specifications of marketable natural gas. The by-products of this processing include ethane, propane, butanes, pentanes, and higher molecular weight hydrocarbons, hydrogen sulfide (which may be converted into pure sulfur), carbon dioxide, water vapor, and sometimes helium and nitrogen.
Therefore, there is a long-felt need for a system that transports gas extracted from the ground without releasing it into the atmosphere. There is also a long-felt need for a system that pressurizes gas extracted from the ground such that it can be stored more efficiently or pumped to a down stream storage container or facility (e.g., loaded into a truck or tank). There is also a long-felt need for a system that can self-regulate the extremely high gas temperatures created by the pressurization process.


A microbead comprising pheromone encapsulated in a coacervate shell is provided. The coacervate shell is entrained in a hydrogel microbead without chemical crosslinking. The microbeads of the present invention are capable of dehydration and rehydration to release of pheromone to the intended environment.

The invention relates broadly to a combination of encapsulation, immobilization and release of active material using hydrogel microbeads. Specifically, the active material is encapsulated in a coacervate shell and immobilized in a hydrophilic microbead.
Methods of eliminating unwanted pests from orchards, crops and forests frequently entail the use of organophosphate insecticides. Alternative methods involve insect mating disruption, where insect pheromones are used to control pests and protect agricultural crop. In insect mating disruption methods, the mating pheromone plume of a female insect is typically masked with other pheromone point sources. This reduces the likelihood of a male insect finding a female, and subsequently disrupts and reduces larvae production. The insect population of the next generation is thus decreased, as well as potential crop damage.
Conventional sprayable pheromone formulations are generally provided in liquid filled microcapsules containing an active. Typically, the microcapsules have a polyurea shell that can be formed using an interfacial process involving an isocyanate and an amine. Microencapsulation by this method has been descibed for example in U.S. Pat. No. 4,487,759 (Nesbitt et al.) These polyurea shells allow actives to be released into the atmosphere for up to a total of 2-3 weeks for most insect pheromones. Shells of polyurea capsules are generally semi-permeable, therefore active material can diffuse across the shells and release slowly with time. Potentially, high concentrations of active in the air can be observed immediately upon delivery or spraying of encapsulated products. This may be attributable to a high occurrence of capsule bursts or potential leaks in microcapsules.
U.S. Pat. No. 4,532,123 (Gardner) teaches capsules containing a pharmaceutical active material in primary capsules, that are further encapsulated within a second shell to create secondary capsules. The intracapsular liquid core of the secondary capsules contain enzymes which slowly hydrolyze the shell of the primary capsules. This slow hydrolysis enables the slow release of active from the primary capsules into the larger capsular core for controlled delivery.
A Japanese patent, JP 8-173794 teaches encapsulation of an amine within small capsules of polymethyl methacrylate shells. These capsules are further encapsulated within an epoxy-amine polymeric shell. Similarly, the amine within the tiny capsules is released into the core of the larger capsule ultimately delivering the amine upon rupturing of the polymeric shells.
Use of interfacial condensation to encapsulate substances such as pharmaceuticals, pesticides and herbicides is taught in U.S. Pat. No. 3,577,515 (Vandegaer). The encapsulation process involves two immiscible liquid phases (typically water and an organic solvent), one being dispersed in the other by agitation, and the subsequent polymerization of monomers from each phase at the interface between the bulk (continuous) phase, and the dispersed droplets. Polyurethanes and polyureas are materials suitable for producing the microcapsules. The microcapsules comprising a polymeric sphere and a liquid centre, ranging from 30 micron to 2 mm in diameter, depending on monomers and solvents used.
Highly viscous and thickened hydrogels have been used to deliver pheromones, fragrances and other non-water soluble actives. U.S. Pat. No. 4,755,377 (Steer) describes a process of encapsulating perfume or fragrant material within an aqueous-based gel composition. The resulting material is in the form of a highly viscous semi-solid. U.S. Pat. No. 5,645,844 (Henderson et al.) describes the use of chitosan paste for delivery of pheromones to disrupt insect mating, where the material can be dispensed by an apparatus such as a caulking gun. Due to their thickness and high viscosity, these materials, however, are generally unsprayable compositions.
Most hydrogels are safe and non-toxic to humans. Hydrogels have been used for the encapsulation of biological materials whereby the formulation is non-lethal to the viability of the cells, proteins, and related materials. U.S. Pat. No. 4,689,293 (Goosen et al.) describes the process of encapsulating living tissue or cells. The encapsulation shell permits the passage of materials and oxygen to the cells and permits the diffusion of the metabolic by-products from the gel.
Coacervation process is well known in the art for uses such as carbonless copy paper capsules and in encapsulation of leuco dyes, drugs, flavorings and fragrances. U.S. Pat. No. 2,800,457 (Green) discloses a gelled colloid that is porous and that the pores may be tightened if the crosslinking step is conducted at pH of 9-10.
Other approaches to crosslinking a coacervate microcapsule have employed non-aldehyde crosslinkers. U.S. Pat. No. 4,402,856 (Schnoring) discloses the use of a natural and/or synthetic tanning agent and a carbonyl compound to harden a gelatin microcapsule. U.S. Pat. No. 5,023,024 (Kyogoku et al.) discloses the use of naturally occurring chemicals of the iridoid class, specifically genipin. U.S. Pat. No. 5,051,304 (David et al.) also discloses the use of tannic acid as a crosslinker.
Although the foregoing approaches have proved satisfactory for crosslinking a coacervate shell under certain conditions, the need still exists to provide coacervate shells that are more environmentally friendly, do not utilize toxic crosslinkers, and are more cost effective than previously disclosed.
The present invention provides a method of encapsulating a pheromone comprising:
a) providing a solution comprising a first polymer capable of forming a microcapsule by complex coacervation; a pheromone; and a second polymer, said second polymer being capable of forming a microcapsule by complex coacervation with the composition comprising the first polymer;
b) establishing a microcapsule having a coacervation shell without chemical crosslinking of said shell;
c) adding a third polymer, said third polymer being suitable to form a hydrogel microbead, in an amount effective to form the microcapsule containing composition; and
d) spraying the microcapsule containing composition into a coordination solution, thereby providing stable hydrogel microbeads comprising microcapsules having a coacervation shell without chemical crosslinking.
Another aspect of the present invention is a method of encapsulating a pheromone wherein the third polymer of step c) above is added before the microcapsule of step b) is established.
The present invention also provides a pheromone that is encapsulated in a coacervate shell by the above named process.
The hydrogel microbead is preferably hydrophilic and is capable of immobilizing a broad spectrum of microencapsulated active materials, either water-soluble or non-water soluble.
In an aspect of the invention, the hydrogel microbead may be made from a water-soluble microcapsule containing material to provide an environmentally friendly microbead. The microbeads may be coated with an adhesive to improve application in an intended environment.
In a further aspect of the invention, the microbeads may be capable of re-hydrating after an initial dehydration and release of active. Thus, the release and longevity of the pheromone can be controlled by adjusting the humidity of the environment in which the microbeads have been delivered.
The present invention provides a pheromone encapsulated within a coacervate shell which in turn is entrained within a hydrogel microbead without an intermediate step of chemically crosslinking the coacervate shell. For purposes of the present invention, a chemical crosslink is a crosslink between two polymers formed by covalent bonds. Thus, the present invention provides effective delivery of pheromones from a hydrogel microbead structure without the use of potentially environmentally unfriendly chemicals, thus avoiding the use of chemicals such as glutaraldehyde, formaldehyde, and tannic acid, among others. The present invention additionally reduces the incidence of premature release of the pheromones from the microcapsules. The present invention also delays and/or prolongs the release of pheromones from the coacervate shell as compared to coacervate shell-formed microcapsules that are not entrained within a hydrogel microbead. Uncrosslinked coacervate microcapsules that are not entrained within a hydrogel microbead are typically unstable. By xe2x80x9cunstablexe2x80x9d is meant that the coacervate microcapsule lacks form or shape to encapsulate the pheromone, thereby rendering it unfit for the purpose of delivering the pheromone material to the intended environment.
In view of the increasing awareness of insecticide toxicity to humans and other environmental concerns, it would be advantageous to provide a pheromone delivery system having an extended release life, as well as having both an encapsulated shell and a hydrogel microbead that is non-toxic and biodegradable. It would also be advantageous to provide a system for sprayable, long-lasting pheromone delivery that would be applicable to a broad spectrum of pheromone material thereby eliminating the issue of reactivity of the pheromone with one or more of the shell components.
The method of the invention can be used to encapsulate pheromones with functional groups such as acetates, aldehydes, ketones, alcohols, esters, epoxies, ethers, or combinations thereof. Pheromones may be defined as compounds which, when naturally produced, are secreted by one member of an animal species which can influence the behavior or development of another member of the same animal species. Pheromones are species-specific and therefore the application of pheromones for insect behavior modification has minimal effect on non-target pests. Pheromones supplied for modification of insect behavior interfere with the xe2x80x9cmate finding processxe2x80x9d by releasing point sources of pheromone, which may compete with or camouflage the pheromone plume of a female. This latter type of action differs from chemical insecticides or insect growth regulators or hormones, in that pheromones target future generations of insects, not present ones. As pheromones are very species-specific and are used only in small quantities, their use is more environmentally acceptable than broadcasting of pesticides.
Many pheromones have an ester terminal group, for example and acetate or formate group. Typically these substances are water-immiscible and incorporation of them into microcapsules by known methods presents no particular problem. Additional pheromones that can be encapsulated and then immobilized within the hydrogel microbeads include aldehydes, esters, alcohols, epoxy compounds, ethers, ketones, or combinations thereof. This invention is particularly advantageous for delivery of pheromones containing reactive ketones in which the double bond of the carbonyl group is conjugated with one or more double bonds, for example acetophenone where the carbonyl group is conjugated with double bonds of the aromatic ring.
Pheromones useful in the invention are preferably insect pheromones. In describing the structure of the a pheromone, the following notation is used: the type (E (trans) or Z(cis)) and position of the double bond or bonds are given first, the number of carbon atoms in the chain is given next and the nature of the end group is given last. To illustrate, the pheromone Z-10 C19 aldehyde has the structure;
Pheromones can be mixtures of compounds with one component of the mixture predominating, or at least being a significant component. Partially water-miscible significant or predominant components of insect pheromones, with the target species in brackets, include, for example: E/Z-11 C14 aldehyde (Eastern Spruce Budworm), Z-10 C19 aldehyde (Yellow Headed Spruce Sawfly), Z-11 C14 alcohol (Oblique Banded Leafroller), Z-8 C12 alcohol (Oriental Fruit moth), E,E-8,10 C12 alcohol (Codling moth), E-11 C14 alcohol (Tufted Apple Budmoth), E-11 C14 acetate (Sparganothis Fruitworm), Z-11 C14 acetate (Blackheaded Fireworm), Z-9 C12 acetate (Grape Berry Moth), Z-11 C14 acetate (Leafroller), E/Z-4 C 13 acetate (Tomato Pinworm), Z,Z/Z,E-7, 11-C 16 acetate (Gossyplure), Z-8-C12 acetate (Oriental Fruit Moth), Z/Z-3,13 C18 acetate (Peach Tree Borer), E,Z/Z,Z-3,13-C18 acetate (Lesser Peach Tree Borer), and 7,8-Epoxy-2-methyl-C18 (Gypsy Moth), among others.
An example of a ketone that is a pheromone is E or Z 7-tetradecen-2-one, which is effective with the oriental beetle. An ether that is not a pheromone but is of value is 4-allylanisole, which can be used to render pine trees unattractive to the Southern pine beetle.
Other compounds may optionally be included in the microcapsules of the invention, including perfumes, fragrances, flavoring agents, co-attractants and the like.
Optionally, oil absorbents can be incorporated into the pheromone droplets. These absorbents can help retain the pheromone droplets within the microcapsules, resulting in longer lasting formulations. Clays and starches could alternatively be used for this purpose.
The concentration of pheromone in the microcapsules of the invention should be at a level such that the hydrogel microbead can still provide a strong, rupture resistant network and deliver an effective amount of the pheromone to the environment to which it is intended. Thus, the pheromone is preferably present in an amount between about 0.1 wt % to about 60 wt % (weight percent) of the total weight of the microbead. More preferably, the amount of pheromone is present in the microbead at between about 0.2 wt % to about 40 wt %; and most preferably between about 0.3 wt % to about 20 wt %.
The present invention relates in part to encapsulation of pheromones within a coacervate microcapsule or shell. Conventional coacervate shells utilize crosslinkers to harden the shell encapsulating the pheromone material. The coacervate shell of the present invention is stable without the use of potentially toxic or undesirable crosslinking agents, such as aldehydes, ketones or acids. Uncrosslinked coacervate microcapsules that are not entrained within a hydrogel microbead are typically unstable. Typical crosslinking agents have toxic effects or are deemed less environmentally friendly. An advantage of the present invention is the ability to avoid use of potentially toxic or undesirable chemical crosslinkers.
Coacervate shells are typically formed by the phase separation resulting from the neutralization of two oppositely charged colloids. Typical colloids usable to form a coacervate shell of the present invention include a cationic polymer and an anionic polymer. Cationic polymers usable for coacervation include gelatin, chitosan, poly(hexamethylene co-guanidine), and poly-L-lysine, among others. Anionic polymers include gum arabic, gum acacia, alginates, carboxymethyl cellulose, ethylene maleic anhydride (EMA), gelatins, carrageenan, poly(acrylic acid), pectin, serum albumin, starch, and polyphosphates, and the like. Preferably, the coacervate shell of the present invention comprises a gelatin and an alginate or gum arabic, or combinations thereof.
The present invention further involves immobilizing a coacervate shell that encapsulates a pheromone within a hydrogel microbead. This immobilization thus provides encapsulated pheromone in a protective microbead format. The microbeads can be suspended in a solution to provide a delivery system for pheromones, where the system is capable of providing extended release periods. The microbead provides physical protection to the microcapsules from external pressures such as those that can occur during a spray delivery, for example. This in turn minimizes pre-mature capsule bursts (rupturing) and prolongs the release period of the pheromone(s). Upon dehydration of the water from the hydrophilic microbead, the microcapsule containing the pheromone remains immobilized within the microbead. The pheromone is able to then release into the desired environment by diffusion through the capsule shell, followed by diffusion past or through the hydrophilic microbead.
Microcapsules having a coacervation shell without chemical crosslinking of the shell are established through a conventional complex coacervation process. In this process, a first polymer and a second polymer capable of forming a coacervation shell with the first polymer are mixed. In this process, the two polymers form a coacervate in response to a change in their environment, such as pH, temperature, dilution, and the like. Typically, the first and second polymer solutions each possess a respective charge. The xe2x80x9cchargexe2x80x9d as used herein relates to the functionality of the polymer such that when the encapsulation composition containing the polymers and the pheromone is adjusted by pH or other environmental manipulations, the polymers interact such that they establish a microcapsule having a coacervation shell without chemical crosslinking of the shell. The procedure of coacervation is within the purview of one skilled in the art.
The composition of cationic and anionic polymers are preferably then caused to form a complex by dilution. In some instances, the pH of the composition may need to be adjusted. Prior to adjusting pH or other environmental conditions, the composition may be mixed such that droplets of pheromone are distributed within an aqueous continuous phase to allow the coacervate shell to form around the droplets, thereby forming relatively uniform, round, or elliptical microcapsules containing pheromone. This dilution and/or pH adjustment causes a gel to be formed around the oil soluble pheromones as the temperatures are lowered to below the gel point of the composition.
The hydrogel microbead of the present invention typically entrains the coacervate microcapsules described above. The microbeads of the present invention may comprise a microcapsule-containing material and pheromone. The hydrogel microbead is also preferably hydrophilic. The degree and extent of agitation as well as the type of surfactant used to form the microbeads can affect the size and the dispersity of microcapsules within the microbead. Microcapsules entrained within the microbead are preferably between about 0.01 nm to about 300,000 nm in diameter. More preferably, the microcapsules are between about 0.5 nm to about 200,000 nm in diameter.
Microcapsule-containing materials useful in the present invention for making the hydrogel microbead are biocompatible, water-soluble, have pendant functional groups, and complex with ions (e.g., polyvalent cations and/or anions) to form hydrogels. Functional groups of the microcapsule-containing material include for example, carboxyls, hydroxyls, primary or secondary amines, aldehydes, ketones, esters, and combinations thereof. Preferably the hydrophilic microcapsule-containing material can be made from naturally occuring polysaccharides, such as alginates, chitosans, gums, agars, carrageenans, or the matrix can be made synthetic, water soluble monomers, oligomers or polymers, such as, for example, polyvinyl alcohol, poly(N-isoproylacrylamide), acrylamides, acrylates, and methacrylates, or combinations thereof.
Suitable naturally occurring polysaccharides include the water-soluble salts of alginic, pectic and hyaluronic acids, the water-soluble salts or esters of polyglucuronic acid, polymanuronic acid, polylygalacturonic acid and polyarabinic acid, and gum kappa-carrageenan. The preferred polysaccharides are the ammonium, magnesium, potassium, sodium and other alkali metal salts of alginic acid, and the most preferred polysaccharide is sodium alginate.
xe2x80x9cAlginatexe2x80x9d is the general name given to alginic acid and its salts. Alginates are composed of D-mannosyluronic (mannuronic-xe2x80x9cMxe2x80x9d) and L-gulopyranosyluronic (guluronic-xe2x80x9cGxe2x80x9d) acid residues. The alginate used to immoblize pheromone droplets should be carefully selected to ensure proper microbead formation, ensure the stability of the microbeads during storage and delivery applications, and ensure that the microbeads are able to shrink and swell appropriately to deliver the desired pheromone over an extended period of time (preferably 4-6 weeks). Preferably, an alginate is chosen such that the microbead formed is sufficient in strength to withstand the shear forces (conditions) placed upon the microbeads during application via a spray nozzle-i.e., the microbeads are resistant to rupture during the spray application.
For strength and stability of the microbeads, it is desirable to choose the molecular weight and M:G ratio of the alginate to obtain preferred properties of the ultimate microbead. Although alginates high in mannuronic acid are generally useful for thickening applications, whereas alginates with a high level of guluronic acid are often used for forming gels, both alginate categories (individually or a mixture thereof) are suitable for the microbeads of the invention. A preferred alginate that imparts strength and rupture resistance is an alginate that has a high level of guluronic acid, e.g., greater than about 30 percent by weight. Alginate compositions with excessive levels of mannuronic acid could result in less stable and less rigid microbeads than high guluronic acid gels. However, high mannuronic acid alginates impart to the microbeads the capability of swelling and absorbing more water than microbeads of high guluronic acid content. Thus, a careful balance of the advantages imparted by each of M and G residues should be considered when choosing a suitable alginate.
Preferably, alginates used in the microbeads of the invention have a molecular weight in the range of about 100,000 to about 2,500,000, more preferably about 200,000 to about 1,500,000. Furthermore, the alginates preferably have an M:G ratio in the range of about 0.2 to about 3.5; more preferably about 0.3 to about 1.85.
Preferred alginates have a high level of guluronic acid, for example are alginates from the algae Laminaria hyperborea, stem, whole plant or frond. Preferred alginates with high levels of mannuronic acid include Ascophyllum nodosum, for example.
Gel matrices that form the hydrogel microbead of the present invention may be formed, for example, by coordinating polysaccharides bearing pendant carboxylate groups. These polysaccharide compounds are composed of water-insoluble alginates which include, with the exception of magnesium and the alkali metal salts, the group II metal salts of alginic acid. The water-insoluble alginate gels are typically formed by the chemical conversion of water-soluble alginates, in an aqueous solution, into water-insoluble alginates. This conversion usually is accomplished by the reaction of a water-soluble alginate with polyvalent cations released from a soluble di- or trivalent metal salt.
Water-soluble alginates can include the ammonium, magnesium, potassium, sodium, and other alkali metal salts of alginic acid. Water-insoluble di-or trivalent metal salts suitable for the present invention should satisfy two requirements: (1) that the water-insoluble metal salt contain a di-or trivalent metal ion capable of complexing with the pendant carboxylate groups of the water-soluble polysaccharide to cause the formation of a water-insoluble polysaccharide gel; and (2) that the water-insoluble metal salt reacts with a water-soluble acid to form a water-soluble metal salt.
A common and suitable alginate gel is composed of calcium aliginate.
The time of gelation of the calcium alginate gels can be accomplished by regulating the concentration of free calcium ions in the solution. Typically, the concentration of free calcium ions is controlled by manipulation of the ionization rate of the calcium salt and/or by the inclusion of other compounds in the solution which react with the free calcium ions.
The process of making the microbeads of the invention preferably comprises making the pheromone-filled microcapsules and dispersing the microcapsule suspension in the hydrophilic microcapsule-containing material. The mixture is then hardened (gelled) to form microbeads. The resulting microbead is a hydrogel microbead, having greater than about 30% water initially. The pheromone-filled microcapsules are dispersed and entrained within the water-polymer microbead.
The hydrophilic microbead with the microcapsules entrained in the microbead can be formed either by ionic interactions or by thermal setting. When forming microbeads by ionic interactions, there are two preferred methods of forming: (1) the spray method and (2) the emusification method. In the spray method, the microcapsule-containing mixture is mixed and then atomized mechanically to form small spherical droplets. The size of the microbeads is generally governed by the intrinsic properties of the emulsion suspension, the feed rate and the coaxial airflow rate.
The droplets which are atomized can then be allowed to free-fall directly into a reacting bath. The reacting bath cures or sets the hydrogels so that they solidify. Reaction bath curing can be achieved through chemical or non-chemical means. For the case of sodium alginates, calcium ions are used to coordinate the polymer chains. A preferred coordination compound is calcium chloride.
For the purpose of the present invention, xe2x80x9ccoordination compoundsxe2x80x9d relates to chemicals or compounds that are usable to give the hydrogel microbead and the coacervate shell structure such that it can be applied to its intended environment. Suitable coordinating compounds are preferably divalent and multivalent ionic compounds, such as low molecular weight inorganic or organic compounds including monomers, oligomers and polymers. An example of a suitable coordination compound is Calcium (Ca++) ions for an alginate.
Sources for the coordination compound calcium ions used in the formation of alginate gels include, for example, calcium carbonate, calcium sulfate, calcium chloride, calcium phosphate, calcium tartrate, calcium nitrate, and calcium hydroxide. Other acceptable coordination compounds may include lanthanum chloride, ferric chloride, cobaltous chloride, as generally are other compounds with multivalent cations, such as calcium (Ca++), copper (Cu++), barium (Ba++), strontium (Sr++) and the like.
Alternatively, an emulsification method can be used to produce hydrogel microbeads. In selecting the continuous phase material, it is preferable that it be immiscible with the aqueous microcapsule-containing material.
The microcapsule-containing material preferably has a range of concentrations usable in practicing the invention. The concentration should be chosen to optimize ease of handling, gelling time, the strength of the hydrogel microbead around the pheromone droplets. For example, a sodium alginate solution can preferably be prepared in a concentration of about 1 to about 10% (w/v) in water, more preferably about 1.5 to about 5% and most preferably from about 1 to 3%. However, if the hydrogel agent concentration is too high, the solution may be so viscous as to hinder the formation of spherical microbeads.
Alternatively, hydrogel microbeads of the invention can be formed, for example, by adding the microcapsule-containing material solution drop-wise to a selected coordination compound. For example, a method can be used whereby droplet formation and coordination compound addition is completed as a one step process by a vibrating nozzle which ejects a hydrogel droplet from one source and coats the droplet with a coordination compound from another. U.S. Pat. No. 4,701,326 teaches use of this method.
In the preferred aspect where alginates are used to immobilize an pheromone, a coordinating solution is preferably made up at a concentration of 1 to 1000 millimolar, more preferably 20 to 500 millimolar and most preferably from 50 to 100 millimolar. The concentration ranges may have to be adjusted, depending on the nature of a coordination compound and microcapsule-containing material.
The microcapsule-containing material and pheromone can be treated with the coordination compound or solution by soaking, spraying, dipping, pouring or any of sever other methods which will deposit an amount of the complexing agent on the droplet. When soaking, the time in solution may be from 1 second to 24 hours, preferably 1 minute to 1 hour, and more preferably from 10 to 30 minutes.
The temperature for hydrogel microbead formation is preferably chosen as to avoid damage or alteration to the pheromone. For example, in the preferred aspect where alginates are utilized, the temperature is preferably in the range of about 1xc2x0 C. to about 70xc2x0 C.; more preferably between about 10xc2x0 C. to about 40xc2x0 C., and most preferably between about 15xc2x0 C. to about 30xc2x0 C.
To immobilize pheromone-filled microcapsules within a temperature setting, the microcapsule-containing material must first be solubilized in water using heat. The heating temperature is preferably be within a range of about 40xc2x0 C. to about 100xc2x0 C. When the microcapsule-containing material is completely dissolved, the temperature of the solution is lowered such that the solution is about 5xc2x0 C. to about 10xc2x0 C. above the gel setting temperature. A suspension containing pheromone-filled microcapsules is then preheated to a similar temperature to that of the microcapsule-containing solution, after which the two mixtures are blended together and mixed homogeneously.
To produce the microbeads, the molten microcapsule-containing material can be atomized through a nozzle system or be emulsified using an oil type continuous phase. In the spray method, the molten suspension can be atomized using coaxial air, for an example, and dropped into an ice bath containing distilled water. The microbead is then formed, entraining the microcapsules therein.
To produce the microbeads using the emulsification method, a continuous oil phase is preheated in a jacketed reactor to the temperature of the molten microcapsule suspension. The continuous phase may be any hydrophobic liquid. The preferred and most convenient liquid is a vegetable oil or mineral oil. Other possible hydrophobic liquids may include hydrofluorethers, siloxanes, or solvents such as cycloxhexanes and chloroforms. The microcapsule suspension is then emulsified in the continuous phase with the aid of a mixer. The mixing is continued until a desired particle size is obtained. The temperature of the reaction mixture is then lowered to that of ice water (about 5xc2x0 C.). The matrix is then formed, entraining the microcapsules therein. The microbeads can then be filtered and washed prior to suspending them in solution for delivery.
The present invention provides microbeads having matrix cores that can provide sufficient immobilization of oil soluble pheromones and alcohol pheromones such that the pheromone can be delivered and sprayed by conventional techniques. The hydrophilic microbead preferably and advantageously imparts the capability of the hydrogel microbeads to immobilize the coacervate shell of oil-soluble and alcohol pheromones, and minimizes the risk of undesired reactivity between the pheromone and its immobilizer. Thus, immobilization of pheromones by use of the microbeads of the invention does not render the immobilized material inert or ineffective.
A further benefit from immobilizing pheromone in hydrogel microbeads is the ability of the hydrogel to xe2x80x9cswellxe2x80x9d under humid conditions and shrink under dry conditions. As used herein, xe2x80x9cswellxe2x80x9d is descriptive of the behavior of a microbead, wherein the size (volume) is enlarged (increased) due to absorption of water. This is likely due to the hydrophilic nature of the microcapsule-containing materials used to immobilize the pheromone.
In the presence of humidity, the hydrogel microbeads are preferably capable of absorbing moisture, rehydrating, and consequently releasing pheromone contained within the microbead. This behavior can be cyclical. Thus, by controlling the humidity (or dryness) of the ambient air, the release rate of pheromone from the microbeads can be controlled such that specific periods of release can be generally predicted. It is therefore possible with the present invention to release the pheromone on demand from the microbead. Release on demand, or xe2x80x9csmart release,xe2x80x9d can be advantageous in those instances where release is preferred at certain times. The microbeads"" ability to further release the pheromone may increase the longeveity of releasing effective amounts of the pheromone. Preferably, the microbeads are delivered to an intended environment in effective amounts to obtain the desired effect. For example, microbeads having pheromones entrained therein, are preferably delivered to a desired area in amounts such that mating disruption is effected and release is accomplished for more than 4 weeks, more preferably, the microbead can release for more than about 6 weeks; and most preferably more than about 8 weeks.
During the drying process (i.e dehydration) a surface film layer will form as a result of water evaporation from the hydrophilic microbead. Both initially and during use, the microbeads are characterized by a large surface area to volume ratio, which helps maintain the rate of diffusion of the pheromone during use. Thus, it has been found that microbeads made according to the method of present invention provide excellent delivery systems as they are capable of releasing the pheromone for extended periods. Furthermore, since the pheromone is dispersed within a water-based microbead, additional protection from environmental conditions (i.e., UV) can be provided.
Although it has been found that microbeads of the invention can be made having a diameter of up to about 5 millimeters (mm), it is preferred that the microbeads be between about 1 micrometer (elm) to about 1000xcexcm and more preferably between about 1 xcexcm to about 500 xcexcm in diameter to ensure that the microbeads are easily sprayable from conventional spray nozzles. Most preferably, to ensure minimal clogging in conventional nozzles, the microbeads are less than about 400 xcexcm in diameter. It is conceivable, however, that with the advent of larger spray nozzles not currently used in the industry, the microbeads can be provided in much greater diameters.
For, spraying applications, particularly aerial spraying, it is desirable that the microbeads be capable of remaining suspended in solution (water) to ensure that the microbeads do not sink, settle, or coagulate in the suspension. This also ensures an even spray coverage. Preferably, the microbeads of the invention are able to remain in suspension, thus minimizing if not eliminating the need to agitate during application and optionally, during storage. Various suspension aids can also be included in the suspension containing the microbeads of the invention. Examples of suitable suspension aids include rhamsam gum, xanthum gum, gellan gum, gelatin, pectin, and gum arabic.
Owing to the handling to which the microbeads are subjected, it is desirable that the microbeads of the present invention should be somewhat elastic, and not frangible. For example, atomization of a suspension during a spray application may force the suspension through two rotating perforated discs that are immediately upstream of the discharge nozzle. Sufficient elasticity of the microbeads minimizes physical damage to the microbeads as they pass through the discs.
The microbeads of the present invention are preferably delivered in suspension in aqueous or solvent-based solutions. For environmental and biologically-friendly reasons, it is preferred that aqueous suspensions be used. Suspension aids are preferably included in the suspension formulations to ensure the microbeads remain suspended in solution.
Preferably, the suspension solution is substantially free of monovalent cations, such as sodium, to avoid degradation or breakdown of the microbeads. In a preferred aspect, a concentration of approximately 50 milliMolar of a coordination compound such as calcium chloride is maintained in a stored solution comprising the microbeads of the invention.
Optionally, adhesive material can be included in the compositions of the invention to assist in retention of the microbeads to an intended substrate. The adhesive material can be provided in various forms, such as for example, latex or a tacky microspheres. Adherent properties imparted to the hydrogel microbeads should result in the microbeads being able to still retain their suspended state and minimize aggregation or coagulation in the aqueous suspension. Furthermore, any adhesive material used to impart adherent properties should not affect the integrity of the particles; it should not dissolve or weaken the microbead(s).
A suitable adhesive material that may be included in the compositions of the invention is adhesive latex. The adhesive latex may be any suitable water-dispersible adhesive available in the art. In the agricultural business, such latex compositions are often called stickers or spreaders. Stickers are used to help non-encapsulated agriculture chemicals adhere to plants. Spreaders are used to help disperse non-encapsulated agriculture chemicals on application. Preferred adhesives are acrylate-based adhesives. One suitable latex is available from Rohm and Haas under the trade designation COMPANION. Another is available from Deerpoint Industries under the trade designation DPI S-100 (a proprietary sticker/spreader). Examples of such adhesives are polymers made from the xe2x80x9csoftxe2x80x9d monomers such as n-butyl acrylate, isooctyl acrylate, or the like, or copolymers made from a soft component, such as isobutylene, n-butyl acrylate, isooctyl acrylate, ethyl hexyl acrylate, or the like; and a polar monomer such as acrylic acid, acrylonitrile, acrylamide, methacrylic acid, methyl methacrylate or the like. Non-spherical polyacrylate adhesives are commercially available, for example, as the Rohm and Haas RHOPLEX line of adhesives. Preferably, the non-spherical polyacrylate adhesive is present in an amount of about 10-35% by weight of the total suspension.
Tacky microspheres of adhesive may alternatively be used to help adhere the hydrogel microbeads of the invention to an intended substrate. The tacky microspheres have sufficient adhesive properties to provide the desired adhesive function, yet there is no danger of completely coating the microbead which may lead to potentially inhibiting the release characteristics of the microbead. The combination of microbeads and tacky microspheres may be applied without the need to modify the orifices of conventional sprayers with minimal clogging or plugging problems. Furthermore, the incorporation of tacky (adhesive) microspheres to the (formulation) suspension of microbeads allows the microbeads"" surfaces to become tacky. The beads can therefore stick to intended surfaces, such as, foliage and branches, for example. The adhesive microspheres, especially if they are hollow, may also absorb some of the pheromone into its own body, thus providing a second mechanism of release of the pheromone. This could result in an overall alteration, preferably an enhancement, of the release profile.
Preferably, the adhesive material is an acrylate- or methacrylate-based adhesive system comprising infusible, solvent dispersible, solvent insoluble, inherently tacky, elastomeric copolymer microspheres as disclosed in U.S. Pat. No. 3,691,140. Alternatively, this adhesive composition may comprise hollow, polymer, acrylate, infusible, inherently tacky, solvent insoluble, solvent dispersible, elastomeric pressure-sensitive adhesive microspheres as disclosed in U.S. Pat. No. 5,045,569. Other suitable adhesives are the tacky microspheres having pendant hydrophilic polymeric or oligomeric moieties that are disclosed in U.S. Pat. No. 5,508,313.
Alternatively, the adhesive comprises between about 60-100% by weight of hollow, polymeric, acrylate, inherently tacky, infusible, solvent-insoluble, solvent-dispersible, elastomeric pressure-sensitive adhesive microspheres having a diameter of at least 1 micrometer, and between about 0-40% by weight of a non-spherical polyacrylate adhesive. The hollow microspheres are made in accordance with the teaching of European Patent Application 371,635.
Yet, another alternative is the association of certain type B gelatins with microencapsulated insecticides, especially those employing polyurea subunits in the microcapsule walls as disclosed in U.S. Pat. No. 4,436,719.
The compositions of the present invention may also include one or more adjuvants including, for example, gelling aids, preservatives, dyes, humectants, fixatives, emulsifiers, extenders, and freeze/thaw stabilizers such as polyhydric alcohols and their esters. These materials are present in an amount effective to achieve their extended function, generally less than about 5% typically less than 2%, by weight of the composition.
Incorporation of a light stabilizer can be included in the microbeads of the invention. Suitable light stabilizers include the tertiary phenylene diamine compounds disclosed in Canadian Patent No. 1,179,682, the disclosure of which is incorporated by reference. The light stabilizer can be incorporated by dissolving it, with the pheromone, in a water-immiscible solvent. Alternatively, a light stabilizer can be incorporated in the microbeads as taught in Canadian Patent No. 1,044,134, the disclosure of which is also incorporated by reference.
Surfactants may be used in the process of forming the microbeads. The incorporation of different surfactants will offer different types of microemulsion drop sizes of the pheromone within the hydrogel as well as dictate the amount of free oil lost in the reacting bath solution. A preferred surfactant has a high critical micelle concentration, such as for example, a product available under the product designation DISPONIL SUS IC 875 (CMCxcx9c1%), available from Henkel (Ambler, Pa.).
Particularly preferred surfactants are nonionic. Examples of suitable surfactants include polyvinylpyrrolidone (PVP) and poly(ethoxy)nonylphenol. PVP is usable and available at various molecular weights in the range of from about 20,000 to about 90,000. PVP having a molecular weight of about 40,000 is preferred. Poly(ethoxy)nonylphenols are commercially available under the trade designation IGEPAL from Rhone-Poulenc (Cranbury, N.J.), with various molecular weights depending on the length of the ethoxy chain. Poly(ethoxy)nonylphenols having the formula:
where n has an average value from about 9 to about 13 can be used. A preferred poly(ethoxy)nonylphenols is available commercially under the product name IGEPAL 630, from Rhone-Poulenc (Cranbury, N.J.)xe2x80x94630 is indicative of the approximate molecular weight of the compound. Other examples of suitable surfactants include polyether block copolymers, such as those available under the trade designations PLURONIC and TETRONIC, both available from BASF (Wash., N.J.), polyoxyethylene adducts of fatty alcohols, such as BRIJ surfactants available from ICI (Wilmington, Del.), and esters of fatty acids, such as stearates, oleates, and the like. Examples of such fatty acids include sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, and the like. Examples of the alcohol portions of the fatty esters include glycerol, glucosyl and the like. Fatty esters are commercially available as surfactants under the trade designation ARLACEL C from ICI (Wilmington, Del.) Various properties of the surfactant, such as for example, chain length, functional groups, and hydrophobic regions, can affect the size of the pheromone droplets formed within the microbeads. For example, use of PVP (having a molecular weight of 40,000) tend to result in production of larger sized pheromone droplets than use of poly(ethoxy)nonylphenols (IGEPAL 630).
Ionic surfactants can alternatively be used in the processes of the invention. Examples of suitable ionic surfactants partially neutralized salts of polyacrylic acids such as sodium or potassium polyacrylate or sodium or potassium polymethacrylate.
The microencapsulated pheromone entrained in the microbeads of the invention are released gradually over time. This is a variant of the meachanism that could occur with conventional microencapsulated materials that do not have a hydrophilic matrix to cushion and protect the pheromone, since an unprotected microcapsule could potentially release the pheromone nearly all at one time, for example at the time of shell rupture. Pheromone release from the microbeads of the invention is preferably and advantageously controllable by controlling the humidity (and dryness) of the environment in which the microbeads are located.
While not being bound by this theory, it is believed that one mechanism of release of the pheromone involves water evaporation from the gel microbead followed by the diffusion of pheromone through the microcapsule shell and then through the hydrophilic microbead. Release (diffusion) by this mechanism could result in a delayed release of the pheromone. In another theorized mechanism, the pheromone becomes entrained in the water from the microbead, and as the water evaporates, the pheromone releases into the atmosphere.
In preferred applications, these hydrogel microbeads would be sprayed followed by water evaporation within the gel. As the hydrogel bead dehydrates, the microbead shrinks in size and releases its pheromone with time. The degree of shrinkage of the microbead from its original size, depending on the components used in the formulation. Preferably, the microbeads shrink about 10% to about 90% from its original size, more preferably from about 40% to about 80%, and most preferably from about 50% to about 70%.
Advantageously, the microbead, upon re-exposure to humidity, can swell and rehydrate itself by absorbing water. Re-exposure to humidity can be performed in various ways. For example, the microbeads"" surfaces can be contacted directly with water or other aqueous solutions. In agricultural applications where pheromones are used, a farmer or caretaker can irrigate the plants and foliage to re-hydrate the hydrogel microbeads. Alternatively, the humidity of the environment or ambient air in which the microbeads are located in can be increased by entraining air droplets in the air. Thus, the microbeads can be xe2x80x9cre-activatedxe2x80x9d by re-hydration, thereby selectively controlling the release times of the pheromone.
The microbeads of the invention can be delivered to an intended substrate by various methods. Pheromone delivery using microbeads depends on various factors, such as for example, the size of release coverage desired. For small concentrated areas, the microbeads can be impregnated into hollow fibres, plastic laminate flakes or twist-ties and then physically attaching the fibres or ties to plants to be protected from insect infestation. For larger areas, spraying (aerially or by backpack) may be the better option.
All patents cited in this specficiation are hereby incorporated by reference.
The following examples are for illustration purposes only and are not meant to limit the scope of the invention. Unless otherwise specified, all parts and percentages are by weight.

Pheromone immobilized in stable hydrogel microbeads


A process for manufacturing a metallized substrate using the island coating method, includes depositing a coating layer containing a radiation curable non-volatile film former. The coated part is then vacuum metallized to form the metal islands of the present invention. A layer of clear resinous protective dielectric topcoat containing a radiation curable non-volatile film former is then deposited to completely cover the layer of metal islands while maintaining the aesthetic properties of the metallizing island coating system at a reduced cost and with minimal variability among parts.

This invention pertains to vacuum deposition of amphoteric materials.
Vacuum metallizing of plastic and similar dielectric substrates is disclosed in various forms including U.S. Patents:
In addition, two reference books are:
Thin Film Phenomena, Kasturi L. Chopra, Robert E. Kreiger Publishing Company, Huntington, N.Y., 1979. pp. 163-189.
Handbook of Thin Film Technology, Leon I. Maissel and Reinhard Glang, McGraw-Hill Book Company, New York, N.Y., 1970., pp. 8-32 to 8-43.
U.S. Pat. Nos. 4,407,871, 4,431,711 and 4,713,143, assigned to assignee of the present invention and incorporated herein by reference, relate to metallizing of plastic articles and more particularly to the structure and spacing of discrete metal islands used to metallize rather than a continuous metal film. The metallizing is performed utilizing the island coating system as detailed in the aforesaid patents. The system includes generally spray depositing sequentially a primer coating layer, a basecoat coating layer, a metallizing layer and a topcoat layer. As disclosed in the above referenced patents, the coating layers contain non-volatile film forming polymers, generally in the range of 10-30% requiring flash time of 20 minutes at ambient temperature and cure times of approximately 30 minutes at 260xc2x0 F. between application of layers.
In addition to proper deposition of the coating layers, the appearance and performance of the commercial product, the conductivity of the metal layer, the corrosion resistance of the metal layer and/or the adhesion of the top coat all relate to the structure and spacing of the islands. The above referenced patents provide further teachings related to nucleation and film growth to the desired island structure and spacing that achieves these ends.
In U.S. Pat. No. 5,290,625, assigned to the assignee of the present invention and incorporated herein by reference, the above process is applied to aluminum parts. In a co-pending application, U.S. Pat. No. 5,468,518, assigned to the assignee of the present invention and incorporated herein by reference, the coating layers are modified to form a combined primer/basecoat layer. The underlying combined primer/basecoat can include a pigment to provide a colored metallic appearance as disclosed in U.S Pat. No. 5,320,869 issued Jun. 14, 1994 and assigned to assignee of the present invention and incorporated herein by reference. In another co-pending application, U.S. Pat. No. 5,464,661, assigned to the assignee of the present invention and incorporated herein by reference, the technology for coating layer deposition is improved to allow film builds of 1.5 to 2.0 mils, eliminating significant coating irregularities.
The current island coating system spray deposits the polymeric constituents of the primer layer, basecoat layer and topcoat layer in organic solvent carriers such as glycol ethers, glycolether acetates, aromatic hydrocarbons and dibasic esters. These solvent carriers pose a waste disposal problem increasing the cost of production significantly, a flammability hazard, as well as requiring significant flash and cure times. If the organic solvents could be eliminated, while still maintaining the aesthetic properties of the metallized appearance, significant savings in time and therefore increased production, improved safety, as well as ease of waste disposal would be attained. Additionally, with the elimination of organic solvents the range of substrates that can be metallized could be increased.
In general, the step of spray depositing is done for batch processing while the parts are being rotated as described in U.S. Pat. No. 5,284,679 issued Feb. 8, 1994 and assigned to the assignee of the present invention, and incorporated herein by reference. However, the use of rotation is not practical when dealing with substrates that are thin sheets such as thin extruded polymers, cellulose based materials and textiles. These thin gauge sheets or sheetstocks require different handling and for high speed production it would be useful to be able to have continuous in-line processing.
Apparel designers would find it advantageous to have a metallized sheetstock made from various materials such as polymers, vinyls, cellulose based materials and textiles, that are flexible, washable, formable, and die cutable. Currently available metallic trims are generally either not truly metallic in appearance, or upon washing and wetting lose metallic luster or cannot be washed at all. Further, it would be advantageous to have materials with a metallized appearance that can be xe2x80x9cironed onxe2x80x9d, i.e. a thermal bonding adhesive, in addition to xe2x80x9cstitched onxe2x80x9d. As one example, athletic shoe manufacturers have a perceived need to individualize their products with unique, identifiable features, as for example lights that are present on one brand of athletic shoes. Metallic trim would be useful in creating such identifiable features.
It would be useful to have thin polymer extrusion metallic finish products that can be cut on high speed electrically resisted die blades without arcing. Further it would be useful to be able to utilize such materials as exterior trim without corrosion and which can be used for in-mold decorating and which have the proper reflectivity or depth of image.
According to the present invention, a process for manufacturing a metallized substrate using the island coating system, includes depositing a first coating layer containing a radiation curable non-volatile film former. The coated substrate is then vacuum metallized to form the metal islands of the present invention and a layer of clear resinous protective dielectric topcoat containing a radiation curable non-volatile film former is deposited to completely cover the layer of metal islands while maintaining the aesthetic properties of the metallizing island coating system at a reduced cost and with minimal variability.
The substrate can be formed parts of various polymers or metals or the substrate can be a sheetstock made from materials such as a thin gauge extruded polymer, vinyl, textile or cellulose based material.
The present invention provides a process of manufacturing substrates/parts, and the manufactured parts/substrates themselves, that have a metallized appearance, that reduces the amount of organic wastes and production time as well as allowing continuous in-line processing of sheetstock utilizing the island coating system.
The part can be made from a substrate material selected from the group comprising crystalline and/or amorphous thermoplastic elastomers such as thermoplastic urethanes, thermoplastic urethane alloys, polyester alloys, thermoplastic olefins, polyamide alloys and metals such as aluminum, magnesium and steel.
Further the substrate material can be in a thin gauge sheet form, i.e. sheetstock. The sheetstock has a thickness range of from 0.002 inches to 2 inches with 0.002 to 0.5 inches being the preferred range. The sheetstock can also include textiles such as, but not limited to, cotton, denim, canvas as well as vinyls and cellulose based materials including rayon.
In-line processing refers to a process herein the material being treated is moved from one holding means and taken up by another and while moving between is treated by the process. For example, reel-to-reel processing would be one means of in-line processing.
The island coating system is then applied as taught in U.S. Pat. Nos. 4,407,871, 4,431,711, 4,713,143, 5,290,625 with the improvements disclosed in the present invention. The island coating system includes generally as a first coating layer either a combined primer/basecoat layer, or separately applied primer and basecoat layers, a metallizing layer and an encapsulating topcoat layer. The prior art teaches that each coating layer contains film forming polymers as disclosed in the above referenced patents and patent applications.
The coatings of the present invention contain oligomers which can be classified as film forming polymers or resins in standard coating technology. The oligomers are blended with monomers which are low viscosity and are considered reactive diluents providing viscosity reduction to the coating and they react with oligomers when exposed to UV light. A photoinitiator is also required.
Two publications which provide general background information on radiation curing are:
Cationic Radiation Curing, J. Koleske, Federation Series on Coatings Technology, Federation of Societies for Coating Technology, June, 1991; and
Radiation Cured Coatings, J. Costanza et al., Federation Series on Coatings Technology, Federation of Societies for Coating Technology, June, 1986.
In the coatings of present invention, the film forming polymers are radiation curable film formers. The radiation curable non-volatile film former is selected from the group consisting of melamine acrylate, urethane acrylate, epoxy acrylate, acrylic acrylate and polyester acrylate.
With the utilization of radiation curable film formers, no organic solvents are required in the present invention. Flammability hazards are eliminated as well as wastes. The present invention provides for the exposure to the radiation to occur outside the coating room, therefore the excess coating fluid can be collected and recycled for reuse.
The formulation of each coating layer is therefore:
Primer
0-5% pigment
30-90% radiation curable film former
1-5% photoinitiator
2-70% monomers
Basecoat
30-90% radiation curable film former
1-5% photoinitiator
2-70% monomers
Combined Primer/basecoat
0-5% pigment
30-90% radiation curable film former
1-5% photoinitiator
2-70% monomers
Topcoat
0-3% UV absorber
30-90% radiation curable film former
1-5% photoinitiator
2-70% monomers
The photoinitiator is selected from the group consisting of phenylketones, benzophenone, diazonium salts, diaryliodonium salts, triarylsulphonium salts, benzoin ethers, thioxantones and oxime esters.
The pigment can be black or other colors such as red, green, yellow or purple. In the preferred embodiment a black pigment is used.
In the practice of the improvements of the present invention, the primer, basecoat and topcoat layers (or coatings) can be applied utilizing spray technology, generally high volume, low pressure spray equipment to atomize the coatings. The coatings may be heated (100xc2x0-120xc2x0 F.) to assist with coating flow out. The coatings are applied while the parts are at ambient or elevated temperature (20xc2x0-150xc2x0 F.). If preformed parts are being coated, the parts can be done in xe2x80x9cbatchxe2x80x9d and in the preferred embodiment while the parts are rotating.
If the substrate is a sheetstock, in-line processing can be used for high volume processing utilizing the present invention. For this process coatings can be applied with spray technology but also roller or knife deposition as is known in the art can be used. D. Satas, Web Processing and Converting Technology and Equipment, VanNostrand, Reinhold, N.Y., 1984; Kallendorf, C. F., ed. Radiation Curing Primer I: Inks Coatings and Adhesives, Rad Tech International Park America, 60 revere Drive, Suite 500, Northbrook, Ill. 60062, 1990. For low volume applications individual sheets can be processed using either current metallization procedures or the present invention.
Generally only one side of the sheetstock is metallized, but both sides can be metallized. The one side metallized can be on the first surface, e.g., the surface of the substrate that faces in the direction of the light impinging on the substrate carrying the discontinuous layer of metal. In this case the light impinging on the surface of the substrate passes through the discontinuous layer of metal first with part of the light being reflected back from the metal islands and not reaching the surface.
Alternatively the metallizing can be on the substrate surface opposite the first surface. In this case the opposite surface, or second surface, has the discontinuous layer of metal formed thereon and the light passes through the substrate (either transparent or translucent material) before it is reflected back through the substrate again from the discontinuous layer of metal.
The coatings in the present invention do not require a flash time since there are no solvents to evaporate. The coatings are cured by ultraviolet radiation from a suitable source such as an ultraviolet lamp for less than five minutes. The coating thicknesses are between 0.5 and 2.0 mils for each coating as set forth in the prior art with 1.5 mil being the preferred thickness.
Because of the elimination of the flash step and the significant reduction in cure time compared to the prior art island coating system, the time to produce metallized parts is reduced. The efficiency of the production line making metallized parts is increased by at least 60% and continuous in-line processing of sheetstock can be undertaken.
In a second embodiment, liquid inorganic carriers such as CO2 can be substituted for part of the organic solvent carriers as marketed by Union Carbide in their UNICARB(copyright) system. Applicant has utilized this system and in the practice of the present invention some organic solvents are necessary to maintain proper flow rate and consistency.
In a further embodiment, a hardcoat layer is applied on the topcoat layer. The hardcoat layer can be applied to improve scratch resistance. This hardcoat layer can be applied to improve scratch resistance where flexibility is not required. This hardcoat layer can be selected from the group consisting thermally cured silicone coatings and UV cured acrylate and methacrylate coatings.
The present invention provides thin extrusion polymer sheetstock with a metallic finish. These thin extrusion polymers have wide application in exterior and interior trims, particularly in the automotive industry. In the prior art sheetstock with a continuous, non-island, metallized layer when cut on high speed electrically resisted die blades would arc. However, metallized sheetstock prepared with the island coating system can be die cut since no arcing can occur because the metal layer is not conductive. In general for these applications, the sheetstock is selected from crystalline and/or amorphous thermoplastic elastomers such as thermoplastic urethanes, thermoplastic urethane alloys, polyester alloys, thermoplastic olefins, polyamide alloys as well as vinyls, textiles and cellulose based materials.
The present invention provides metallized thin extruded elastomeric plastic sheets, 0.002 to 0.010 inches in thickness, which can be used effectively in trim applications without crinkle. Because of the flexible nature of the island coating these sheets can be stretched over complex geometric shapes as well as be xe2x80x9cmolded inxe2x80x9d to complex shaped products to eliminate the need for an adhesive. In second surface applications, depth of image (DOI) provides an exact image as does chrome without the performance problems of chrome.
The present invention also provides a metallized substrate which is flexible, washable, and can be either attached with adhesive or stitched to an appropriate object and in particular to wearing apparel. The metallization can be performed either as taught by U.S. Pat. Nos. 4,407,871, 4,431,711 and 4,713,143, or with the improvements of the present invention. The object can be clothes, shoes or the like.
These improvements allow the substrate to be materials which should not be exposed to organic solvents such as textiles and continuous in-line processing, i.e. metallizing, can be used to manufacture the substrate. The substrate for use in apparel and trims is generally selected from the group consisting of polymers, generally a thermoplastic urethane (TPU), vinyls, cellulose derived materials such as paper, wood and rayon, and textiles such as cotton, wool and silk. The substrate can be in any shape, but in the preferred embodiment it is in sheet form so that it can be die cut into the appropriate shape to be applied to apparel. Further, in another preferred embodiment the substrate can be laundered using standard procedures and can go through the drying cycle of a dryer. Polyester elastomer substrates such as HytrelÏ and polyurethane elastomer substrates such as RyniteÏ have been used in the present invention as well as thermoplastic polyester sheetstock such as EstaneÏ. The substrate can be formed into trims for apparel or apparel trim itself can be processed with the present invention. Further articles of clothing themselves, such as shoes, can also be metallized with the present invention.
Additional appearance modifications can be achieved by either mechanically abrading the metal layer in random or structured patterns prior to topcoating. xe2x80x9cSplatteringxe2x80x9d the metal layer with 1% nitric, sulfuric or hydrochloric acid prior to topcoating also provides a mottled visual effect.
The present invention also provides the advantages that different pigments can be added to the basecoats or dyes added to the topcoat to produce different colored appearances. Alternatively, the substrate itself can have color as set forth in the ""869 Patent. Also, secondary accents can be achieved by painting directly over the topcoat. Additionally, ink transfers in a variety of patterns can also be applied in order to produce a variety of looks, as for example snakeskin and geometric patterns.
The process provides metallized sheetstock which can be formed into trim which are metallic in appearance and are flexible, washable and formable into sheets for die cutting. The process also provides for the application of the island coating system on both cellulose derived and textile materials.