WO2009088494A1

WO2009088494A1 - Image recording media and image layers

Info

Publication number: WO2009088494A1
Application number: PCT/US2008/050212
Authority: WO
Inventors: Mehrgan Khavari; Molly Hladik; Susan Bailey; Paul Felice Reboa; Vladek Kasperchik
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2008-01-04
Filing date: 2008-01-04
Publication date: 2009-07-16

Abstract

Imaging layers, optical disks, and methods of preparation of each, are disclosed.

Description

IMAGE RECORDING MEDIA AND IMAGING LAYERS

BACKGROUND Compositions that produce a color change upon exposure to energy in the form of light are of great interest in producing images on a variety of substrates. For example, labeling of optical storage media such as Compact Discs, Digital Video Discs or Blue Laser Discs (CD, DVD, or Blue Laser Disc) can be routinely accomplished through screen-printing methods. While this method can provide a wide variety of label content, it tends to be cost ineffective for run lengths less than 300-400 discs because the fixed cost of unique materials and set-up are shared by all the discs in each run. In screen-printing, a stencil of the image is prepared, placed in contact with the disc and then ink is spread by squeegee across the stencil surface. Where there are openings in the stencil the ink passes through to the surface of the disc, thus producing the image. Preparation of the stencil can be an elaborate, time-consuming and expensive process.

In recent years, significant increases in use of CD/DVD discs as a data distribution vehicle have increased the need to provide customized label content to reflect the data content of the disc. For these applications, the screen-label printing presents a dilemma as discs are designed to permit customized user information to be recorded in standardized CD, DVD, or Blue Laser Disc formats. Today, for labeling small quantities of discs, popular methods include hand labeling with a permanent marker pen, using an inkjet printer to print an adhesive paper label, and printing directly with a pen on the disc media which has a coating that has the ability to absorb inks. The hand printing methods do not provide high quality and aligning a separately printed label by hand is inexact and difficult. It may therefore be desirable to design an optical data recording medium

(e.g., CD, DVD, or Blue Laser Disc) which can be individually labeled by the user easily and inexpensively relative to screen-printing while giving a high quality label solution. It may also be desirable to design an optical data recording medium that accepts labeling via multiple methods, thus reducing the amount of inventory necessarily carried by optical data recording merchants and end users. White powder formation on the optical data recording medium is a concern for forming a label on the optical data recording medium. The white powder forms because of interactions among components of the image recording layer. Therefore, a need exists for the reduction or elimination of white powder formation on optical data recording media.

SUMMARY

Briefly described, embodiments of this disclosure include imaging coatings, optical disks including the imaging layers, and method for preparing an optical disk.

One exemplary embodiment of the optical disk, among others, includes: a substrate having a first side and a second side, wherein the first side stores digital data, wherein the second side includes an imaging layer, wherein the imaging layer is formulated to substantially eliminate or eliminate white powder formation up to temperatures of about 60° C. The imaging layer includes a matrix including a monoacrylate and a diacrylate, wherein the monoacrylate is greater than about 30 wt% of the imaging layer, wherein the diacrylates is less than about 10 wt% of the imaging layer, wherein the monoacrylate is selected from isobornyl acrylate, N-butylcarbamide acrylate, or a combination thereof, wherein the diacrylate is tricyclodecanedimethanol diacrylate; a radiation-absorbing compound; an activator; and a color former. One exemplary embodiment of the method for preparing an optical disk, among others, includes: providing a matrix including a monoacrylate and a diacrylate, wherein the monoacrylate is greater than about 30 wt% of the imaging layer, wherein the diacrylates is less than about 6 wt% of the imaging layer, wherein the monoacrylate is selected from isobornyl acrylate, isobornyl acrylate, N-butylcarbamide acrylate, or a combination thereof, wherein the diacrylate is tricyclodecanedimethanol diacrylate; mixing the radiation-absorbing compound, the activator, and the color former, in the matrix to form a matrix mixture; and disposing the matrix mixture onto a substrate to form the imaging layer, wherein the imaging layer is formulated to substantially eliminate or eliminate white powder formation up to temperatures of about 60° C.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of this disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 illustrates an illustrative embodiment of the imaging medium. FIG. 2 illustrates a representative embodiment of a printer system.

DETAILED DESCRIPTION

Embodiments of the present disclosure will employ, unless otherwise indicated, techniques of synthetic organic chemistry, ink chemistry, media chemistry, and the like, that are within the skill of the art. Such techniques are explained fully in the literature.

The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to perform the methods and use the compositions disclosed and claimed herein. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.) but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in ⁰C, and pressure is at or near atmospheric. Standard temperature and pressure are defined as 20 ⁰C and 1 atmosphere.

Before the embodiments of the present disclosure are described in detail, it is to be understood that, unless otherwise indicated, the present disclosure is not limited to particular materials, reagents, reaction materials, manufacturing processes, or the like, as such can vary. It is also to be understood that the terminology used herein is for purposes of describing particular embodiments only, and is not intended to be limiting. It is also possible in the present disclosure that steps can be executed in different sequence where this is logically possible.

It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a support" includes a plurality of supports. In this specification and in the claims that follow, reference will be made to a number of terms that shall be defined to have the following meanings unless a contrary intention is apparent.

As used herein, the term "leuco-dye" means a color-forming substance that is colorless or of a first color in a non-activated state, and subsequently exhibits color or changes from the first color to a second color in an activated state. As used herein, the term "activator" is a substance that reacts with a color former such as a leuco-dye, causing the leuco-dye to alter its chemical structure and change or acquire color.

As used herein, the term "antenna" is a radiation-absorbing compound. The antenna readily absorbs a desired specific wavelength of the marking radiation.

Discussion

Embodiments of the disclosure include imaging layers, optical disks, and methods of making each. The optical disk includes an imaging layer or coating including, but not limited to, a matrix, a color former, an activator, and optionally a radiation-absorbing compound. As mentioned above, white powder formation can be attributed to interaction of the color-former, the activator, and the matrix. Matrix formulations of the present disclosure substantially eliminate (e.g., white powder formation is less than 10%) or eliminate white powder formation. In particular, the white powder formation is substantially eliminated or eliminated while also providing resistance to white powder formation associated with "fingerprints". Unlike prior formulations, embodiments of the present disclosure provide an imaging layer formulation that includes a combination of matrix materials that substantially eliminate or eliminate white powder formation up to temperatures of about 60° C. It has been established in laboratory procedures that exposure to 60° C causes accelerated aging of the coating. This procedure enables the determination of certain coating properties in matter of days rather than months and in some cases years. In this disclosure accelerated testing at 60° C at 30% relative humidity and 24, 48, and 96 hours was used. For example accelerated testing at 48 hours simulates aging in excess of 2 to 3 years of exposure to ambient conditions. Although extensive testing was done at 96 hours, the discussion presented in this disclosure centers on 48 hours. The substantial elimination or elimination of white powder from embodiments of the present disclosure was unexpectedly and fortuitously determined by specifically formulating the imaging layer as disclosed herein. Additional details regarding embodiments of the present disclosure are described below and in the Examples. The imaging layer can be a coating disposed onto a substrate to form an optical disk.

A clear mark and excellent image quality can be obtained by directing radiation energy (e.g., a 780 nm laser operating at 35 mW) at areas of the imaging layer on which a mark is desired. As mentioned above, the components in the imaging layer used to produce the mark via a color change upon stimulation by energy can include, but are not limited to, the matrix, the color former (e.g., a leuco dye), an activator, and, optionally, the radiation-absorbing compound. In an embodiment, the components can be dissolved into a matrix material. In another embodiment, one or more components can be insoluble or substantially insoluble in the matrix material at ambient temperatures, where the components are uniformly dispersed throughout the matrix material. In an embodiment, when the radiation-absorbing compound absorbs a particular radiation energy, the heat generated from the radiation-absorbing compound allows a reaction between the color former and the activator to occur and to produce a color change (e.g., a mark). In another embodiment, the radiation-absorbing compound is not used and the laser irradiation is directly absorbed by the imaging layer and heats the matrix material and its components, which allows the color former and the activator to react to produce a color change.

The radiation energy absorber functions to absorb radiation energy, convert the energy into heat, and deliver the heat to the components of the matrix. The radiation energy may then be applied by way of an infrared laser. Upon application of the radiation energy, both the color former and the activator may become heated and mix, which causes the color former to become activated and cause a mark (color) to be produced. FIG. 1 illustrates an embodiment of an imaging medium 10, in particular, an optical disk. The imaging medium 10 can include, but is not limited to, a substrate 12 and an imaging layer 14. The substrate 12 can be a substrate upon which it is desirable to make a mark, such as, but not limited to, an optical disk (e.g., a compact disk (CD) (e.g., CD-R/RW/ROM) and a digital versatile disk (DVD) (e.g., DVD-R/RW/ROM). In particular, the substrate 12 includes an

"optical disk" or "optical data recording medium" which is meant to include digital information such as audio, video, multi-media, and/or software disks that are machine readable in a CD and/or DVD drive, or the like. The substrate 12 includes a data side (not shown) (typically the side opposite the layer 14) that includes one or more data layers that encode information such as, but not limited to, audio, video, pictures, music, computer code, combinations thereof, and the like. Examples of optical disk formats include writeable, recordable, and rewriteable disks such as DVD-HD, Blu-ray, DVD, DVD-R, DVD-RW, DVD+R, DVD+RW, DVD-RAM, CD, CD-ROM, CD-R, CD-RW, and the like. Other like formats can also be included, such as similar formats and formats to be developed in the future. The imaging layer 14 can include, but is not limited to, the matrix, the color former (e.g., a leuco dye), the activator, and optionally the radiation-absorbing compound, as well as other components typically found in the particular media to be produced. The imaging layer 14 may be applied to the substrate 12 via any acceptable method, such as, but not limited to, rolling, spraying, and screen- printing. In addition, one or more layers can be formed between the imaging layer 14 and the substrate 12 and/or one or more layer can be formed on top of the imaging layer 14. In one embodiment, the imaging layer 14 is part of a CD or a DVD.

To form a mark, radiation energy is directed imagewise at one or more discrete areas of the imaging layer 14 of the imaging medium 10. The form of radiation energy may vary depending upon the equipment available, ambient conditions, the desired result, and the like. The radiation energy can include, but is not limited to, infrared (IR) radiation, ultraviolet (UV) radiation, x-rays, and visible light. In an embodiment, the radiation-absorbing compound absorbs the radiation energy and heats the area of the imaging layer 14 to which the radiation energy impacts. The heat may cause the color former and the activator to mix. The color former and the activator may then react to form a mark (color) on certain areas of the imaging layer 14.

FIG. 2 illustrates a representative embodiment of a print system 20. The print system 20 can include, but is not limited to, a computer control system 22, an irradiation system 24, and print media 26 (e.g., imaging medium). The computer control system 22 is operative to control the irradiation system 24 to cause marks (e.g., printing of characters, symbols, photos, and the like) to be formed on the print media 26. The irradiation system 24 can include, but is not limited to, a laser system, a UV energy system, a IR energy system, a visible energy system, a x-ray system, and other systems that can produce radiation energy to cause a mark to be formed on the imaging layer 14. The print system 20 can include, but is not limited to, a laser printer system and an ink-jet printer system. In addition, the print system 20 can be incorporated into a digital media system. For example, the print system 20 can be operated in a digital media system to print labels (e.g., the layer is incorporated into a label) onto digital media such as CDs and DVDs. Furthermore, the print system 20 can be operated in a digital media system to directly print onto the digital media (e.g., the layer is incorporated the structure of the digital media). As mentioned above, the imaging layer can include, but is not limited to, the matrix, the color former (e.g., a leuco dye), the activator, and optionally the radiation-absorbing compound.

The matrix (also referred to as "matrix material", "matrix compound", and "lacquer") can include compounds capable of and suitable for dissolving and/or dispersing the radiation-absorbing compound, the activator, and/or the color former. The matrix can include a mixture of monofunctional monomer (also referred to as "monoacrylates") and difunctional monomer or oligomer (also referred to as "diacrylates"). The monoacrylates are greater than about 25 wt%, greater than about 30 wt%, greater than about 35 wt%, greater than about 40 wt%, greater than about 50 wt%, and greater than about 55 wt% of the imaging layer. The diacrylates are less than about 30 wt%, less than about 10 wt%, less than about 8 wt%, and less than about 6 wt% of the imaging layer.

It should be noted that the remaining portion of the matrix (e.g., less than about 10%, about 8%, about 6%, and about 5%) is composed of one or more lacquer-soluble polymers (e.g., copolymers of methylmethacrylate and butylacrylate (sold under the trade mark Paraloid from Rohm & Haas), copolymers of cellulose acetate butyrate (as known as CABs sold by Eastman Chemicals), copolymers of styrene maleic anhydride (sold by Sartomer), and copolymers of vinyl butyral, acetate, and alcohol (sold by Kuraray and Wacker) which can be used to enhance one or more properties (e.g., coating gloss, surface roughness, stiffness, and the like) of the imaging layer.

The monoacrylate can include compounds such as, but not limited to, isobornyl acrylate, N-butylcarbamide acrylate, or a combination thereof. The diacrylate can include compounds such as, but not limited to, tricyclodecanedimethanol diacrylate.

In an embodiment, the isobornyl acrylate is greater than about 22 wt%, greater than about 25 wt%, greater than about 30 wt%, greater than about 40 wt%, greater than about 55 wt%, and greater than about 55 wt% of the imaging layer.

In an embodiment, the matrix includes isobornyl acrylate and N- butylcarbamide acrylate in the ratios of about 60:30, 57:27, 55:25, and 52:22. The combination of isobornyl acrylate and N-butylcarbamide acrylate is greater than about 22 wt%, greater than about 25 wt%, greater than about 30 wt%, greater than about 40 wt%, greater than about 55 wt%, and greater than about 55 wt% of the imaging layer.

In an embodiment, the tricyclodecanedimethanol diacrylate is less than about 6 wt%, less than about 5 wt%, and less than about 4.7 wt%, of the imaging layer.

In addition, the matrix can include other acrylates such as, but not limited to: hexamethylene diacrylate, tripropylene glycol diacrylate, lauryl acrylate, isodecyl acrylate, neopentyl glycol diacrylate, 2-phenoxyethyl acrylate, 2(2- ethoxy)ethylacrylate, polyethylene glycol diacrylate and other acrylated polyols, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, ethoxylated bisphenol- A diacrylate, acrylic oligomers with epoxy functionality, and the like. The other component, soluble polymer, is about 4 or 5 weight % of the imaging layer. In an embodiment, the imaging layer includes hexanedioldiacrylate in an amount of less than about 5 wt% of the imaging layer.

In addition, the matrix can include, but is not limited to, monofunctional and difunctional acrylates, with a photopackage. A photopackage may include light absorbing species that initiate reactions for curing of a lacquer, such as, by way of example, benzophenone derivatives. Other examples of photoinitiators for free radical polymerization monomers and pre-polymers include but are not limited to thioxanethone derivatives, anthraquinone derivatives, acetophenones and benzoine ethers.

The matrix is about 30 wt% to 70 wt% of the imaging layer and about 45 wt% to 55 wt% of the imaging layer. The term "color former" is a color forming substance, which is colorless or one color in a non-activated state and produces or changes color in an activated state. The color former can include, but is not limited to, leuco dyes and phthalide color formers (e.g., fluoran leuco dyes and phthalide color formers as described in "The Chemistry and Applications of Leuco Dyes", Muthyala, Ramiah, ed., Plenum Press (1997) (ISBN 0-306-45459-9), incorporated herein by reference).

The color former can include a wide variety of leuco dyes. Suitable leuco dyes include, but are not limited to, fluorans, phthalides, amino-triarylmethanes, aminoxanthenes, aminothioxanthenes, amino-9, 10-dihydro-acridines, aminophenoxazines, aminophenothiazines, aminodihydro-phenazines, aminodiphenylmethanes, aminohydrocinnamic acids (cyanoethanes, leuco methines) and corresponding esters, 2(p-hydroxyphenyl)-4,5-diphenylimidazoles, indanones, leuco indamines, hydrazines, leuco indigoid dyes, amino-2,3- dihydroanthraquinon- es, tetrahalo-p,p'-biphenols, 2(p-hydroxyphenyl)-4,5- diphenylimidazoles, phenethylanilines, phthalocyanine precursors (such as those available from Sitaram Chemicals, India), and other known leuco dye compositions. Experimental testing has shown that phthalide and fluoran-based dyes are one class of leuco dyes that exhibit particularly desirable properties. In one aspect of the present disclosure, the leuco dye can be a fluoran, phthalide, aminotriarylmethane, or mixture thereof. Several non-limiting examples of suitable fluoran based leuco dyes include 3-diethylamino-6-methyl-7- anilinofluorane, 3-(N-ethyl-p-toluidino)-6-meth- yl-7-anilinofluorane, 3-(N-ethyl-N- isoamylamino)-6-methyl-7-anilinofluoran- e, 3-diethylamino-6-methyl-7-(o,p- dimethylanilino)fluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-piperidino-6- methyl-7-anilino- fluorane, 3-(N-cyclohexyl-N-methylamino)-6-methyl-7- anilinofluorane, 3-diethylamino-7-(m-trifluoromethylanilino)fluorane, 3- dibutylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-chloro-7-anil- inofluorane, 3-dibutylamino-7-(o-chloroanilino)fluorane, 3-diethylamino-7-(o- chloroanilino)fluorane, 3-di-n-pentylamino-6-methyl-7- -anilinofluoran, 3-di-n- butylamino-6-methyl-7-anilinofluoran, 3-(n-ethyl-n~isopentylamino)-6-methyl-7- anilinofluoran, 3-pyrrolidino-6-methyl^:7-anilinofluoran, 1(3H)- isobenzofuranone,4,5,6,7-t- etrachloro-3,3-bis[2-[4-(dimethylamino)phenyl]-2-(4- methoxyphenyl)ethenyl]- , 2-anilino-3-methyl-6-(N-ethyl-N-isoamylamino)fluorane (S-205 available from Nagase Co., Ltd), and mixtures thereof. Suitable aminotriarylmethane leuco dyes can also be used in the present invention such as tris(N,N-dimethylaminophenyl)methane (LCV); tris(N,N-diethylaminophenyl) methane (LECV); tris(N,N-di-n-propylaminophenyl)methane (LPCV); tris(N,N-di- n-butylaminophenyl) methane (LBCV); bis(4-diethylaminophenyl)- -(4- diethylamino-2-methyl-phenyl)methane (LV-1 ); bis(4-diethylamino-2-meth- ylphenyl)-(4-diethylamino-phenyl)methane (LV-2); tris(4-diethylamino-2-met- hylphenyl)methane (LV-3); bis(4-diethylamino-2-methylphenyl)(3,4-dimethoxy- phenyl)methane (LB-8); aminotriarylmethane leuco dyes having different alkyl substituents bonded to the amino moieties wherein each alkyl group is independently selected from C1-C4 alkyl; and aminotriaryl methane leuco dyes with any of the preceding named structures that are further substituted with one or more alkyl groups on the aryl rings wherein the latter alkyl groups are independently selected from C1-C3 alkyl. Other leuco dyes can also be used in connection with the present invention and are known to those skilled in the art. A more detailed discussion of some of these types of leuco dyes may be found in U.S. Pat. Nos. 3,658,543 and 6,251 ,571 , each of which are hereby incorporated by reference in their entireties. Additional examples and methods of forming such compounds can be found in Chemistry and Applications of Leuco Dyes, Muthyala, Ramaiha, ed., Plenum Press, New York, London; ISBN: 0-306-45459- 9, which is hereby incorporated by reference. The color former may exist in the imaging layer as either: a) a separate phase finely dispersed in the matrix phase (preferable for many fluoran Leuco- dyes) (e.g., Leuco-dye particle size < 5 μm, preferably < 2 μm, most preferably < 1 μm) (In this case heating of the coating by radiation results of Leuco-dye dissolution in the matrix); b) or being completely dissolved in the matrix phase at the stage of coating preparation. For example, some of the commercial phthalide Leuco-dyes such as 3,3'-Bis(1-n-octyl-2-methylindol-3-yl) phthalide commercially known as Pergascript Red I 6B or Specialty Red 16 have relatively high solubility (up to about 20 wt.%) in many commercially available acrylate and methacrylate monomers. The color former is from about 2 wt% to 50 wt% of the imaging layer and from about 5 wt% to 30 wt% of the imaging layer. As used herein, the term "activator" is a substance that reacts with a color former, causing the color former to alter its chemical structure and change or acquire color.

The activator can include a compound that has an acid such as, but not limited to, a Lewis acid, has a functionality such as a complexed transition metal, metal salt, phenolic compound, and combinations thereof, and can be reactive with leuco dyes with or without introduction of energy in the form of light and/or heat.

In one embodiment, the activator can be a metal salt of an aromatic carboxylic acid. The metal of the metal salt can include, but is not limited to, transition metals such as zinc, tin, nickel, iron, and other transition metals. In one embodiment, the metal salt activator can be a zinc salt of an aromatic carboxylic acid. Other metal salt activators include zinc salicylate, tin salicylate, zinc 2- hydroxy naphthoate, 3,5-di-α-methylbenzyl zinc salicylate, metal salts of rhodanate, xanthate, aluminate, titanate, and zirconate, and mixtures thereof.

The activator can include, but is not limited to, a phenolic resin, zinc chloride bisphenol, hydroxybenzoate, amidophenol, anilides with hydroxyl groups, and benzoamides with hydroxyl groups including N-(4-Hydroxyphenyl) acetamide, 2-acetamidophenol, 3-acetamidophenol, salicylanilide, p- hydroxybenzamide, p-hydroxyphenyl acetamide, 3-hydroxy-2-napthanilide, o- hydroxybenzanilide, 4-hydroxyphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, Bis(4-hydroxy-3-allylphenyl) sulfone, 2,2',5,5'-Tetrahydroxy diphenyl sulfone, 4- hydroxyphenyl-4'-isopropoxyphenly sulfone, 2,2-Bis(4-hydroxyphenyl)propane, and combinations thereof. The activator can be about 2 wt% to 20 wt% of the imaging layer, about 10 wt% to 18 wt% of the imaging layer, and about 13 wt% to 17 wt% of the imaging layer.

The term "radiation-absorbing compound" (e.g., "an antenna") means any radiation-absorbing compound that readily absorbs a desired specific wavelength of the marking radiation. The radiation-absorbing compound can be a material that effectively absorbs the type of energy to be applied to the imaging medium 10 to effect a mark or color change. The radiation-absorbing compound can act as an energy antenna, providing energy to surrounding areas upon interaction with an energy source. As a predetermined amount of energy can be provided by the radiation-absorbing compound, matching of the radiation wavelength and intensity to the particular antenna used can be carried out to optimize the system within a desired optimal range. Most common commercial applications can require optimization to a development wavelength of about 200 nm to about 1000 nm, although wavelengths outside this range can be used by adjusting the radiation-absorbing compound and color forming composition accordingly. Suitable radiation-absorbing compound can be selected from a number of radiation absorbers such as, but not limited to, aluminum quinoline complexes, porphyrins, porphins, indocyanine dyes, phenoxazine derivatives, phthalocyanine dyes, polymethyl indolium dyes, polymethine dyes, guaiazulenyl dyes, croconium dyes, polymethine indolium dyes, metal complex IR dyes, cyanine dyes, squarylium dyes, chalcogeno-pyryloarylidene dyes, indolizine dyes, pyrylium dyes, quinoid dyes, quinone dyes, azo dyes, and mixtures or derivatives thereof. Other suitable radiation-absorbing compounds can also be used and are known to those skilled in the art and can be found in such references as "Infrared Absorbing Dyes", Matsuoka, Masaru, ed., Plenum Press, New York, 1990 (ISBN 0-306-43478-4) and "Near-Infrared Dyes for High Technology Applications", Daehne, Resch-Genger, Wolfbeis, Kluwer Academic Publishers (ISBN 0-7923- 5101-0), both incorporated herein by reference.

Various radiation-absorbing compounds can act as an antenna to absorb electromagnetic radiation of specific wavelengths and ranges. Generally, a radiation antenna that has a maximum light absorption at or in the vicinity of the desired development wavelength can be suitable for use in the present disclosure. For example, the color forming composition can be optimized within a range for development using infrared radiation having a wavelength from about 720 nm to about 900 nm. Common CD-burning lasers have a wavelength of about 780 nm and can be adapted for forming images by selectively developing portions of the imaging layer. Radiation-absorbing compound which can be suitable for use in the infrared range can include, but are not limited to, polymethyl indoliums, metal complex IR dyes, indocyanine green, polymethine dyes such as pyrimidinetrione- cyclopentylidenes, guaiazulenyl dyes, croconium dyes, cyanine dyes, squarylium dyes, chalcogenopyryloarylidene dyes, metal thiolate complex dyes, bis(chalcogenopyrylo)polymethine dyes, oxyindolizine dyes, bis(aminoaryl)polymethine dyes, indolizine dyes, pyrylium dyes, quinoid dyes, quinone dyes, phthalocyanine dyes, naphthalocyanine dyes, azo dyes, hexafunctional polyester oligomers, heterocyclic compounds, and combinations thereof.

Several specific polymethyl indolium compounds are available from Aldrich Chemical Company and include 2-[2-[2-chloro-3-[2-(1 ,3-dihydro-1 ,3,3-trimethyl- 2/-/-indol-2-ylidene)-ethylidene]-1 -cyclopenten-1 -yl-ethenyl]-1 ,3,3-trimethyl-3/-/- indolium perchlorate; 2-[2-[2-chloro-3-[2-(1 ,3-dihydro-1 ,3,3-trimethyl-2H-indol-2- ylidene)-ethylidene]-1 -cyclopenten-1 -yl-ethenyl]-1 , 3, 3-trimethyl-3W-indolium chloride; 2-[2-[2-chloro-3-[(1 ,3-dihydro-3,3-dimethyl-1 -propyl-2H-indol-2-ylidene) ethylidene]-1-cyclohexen-1-yl] ethenyl]-3,3-dimethyl-1-propylindolium iodide; 2-[2- [2-chloro-3-[(1 ,3-dihydro-1 ,3,3-trimethyl-2H-indol-2-ylidene) ethylidene]-1- cyclohexen-1-yl]ethenyl]-1 ,3,3-trimethylindolium iodide; 2-[2-[2-chloro-3~[(1 ,3- dihydro-1 ,3,v3-trimethyl-2H-indol-2-ylidene) ethylidene]-1 -cyclohexen-1 - yl]ethenyl]-1 ,3,3-trimethylindolium perchlorate; 2-[2-[3-[(1 ,3-dihydro-3,3-dimethyl- 1 -propyl-2H-indol-2-ylidene) ethylidene]-2-(phenylthio)-1 - cyclohexen-1 -yl] ethenyl]-3,3-dimethyl-1-propylindolium perchlorate; and mixtures thereof. Alternatively, the radiation-absorbing compound can be an inorganic compound (e.g., ferric oxide, carbon black, selenium, or the like). Polymethine dyes or derivatives thereof such as a pyrimidinetrione-cyclopentylidene, squarylium dyes such as guaiazulenyl dyes, croconium dyes, or mixtures thereof can also be used in the present invention. Suitable pyrimidinetrione-cyclopentylidene infrared antennae include, for example, 2,4,6(1 H,3H,5H)-pyrimidinetrione 5-[2,5-bis[(1 ,3- dihydro- 1 ,1 ,3-dimethyl-2H-indol-2-ylidene) ethylidene] cyclopentylidene]-1 ,3- dimethyl- (9Cl) (S0322 available from Few Chemicals, Germany). In another embodiment, the radiation-absorbing compound can be selected for optimization of the color forming composition in a wavelength range from about 600 nm to about 720 nm, such as about 650 nm. Non-limiting examples of suitable radiation-absorbing compound for use in this range of wavelengths can include indocyanine dyes such as 3H-indolium,2-[5-(1 ,3- dihydro-3,3-dimethyl-1-propyl-2H-indol-2-ylidene)-1 ,3-pentadienyl]-3,3-dimethyl- 1-propyl-,iodide) (Dye 724 Amax 642 nm), 3H-indolium,1-butyl-2-[5-(1-butyl-1,3- dihydro-3,3-dimethyl-2H-indo!-2-ylidene)-1 ,3-pentadienyl] -3,3-dimethyl- perchlorate (Dye 683 A_maχ 642 nm), and phenoxazine derivatives such as phenoxazin-5-ium, 3,7- bis(diethylamino)-perchlorate (oxazine 1 A_max = 645 nm). Phthalocyanine dyes having an A_max of about the desired development wavelength can also be used such as silicon 2,3-napthalocyanine bis(trihexylsilyloxide) and matrix soluble derivatives of 2,3-napthalocyanine (both commercially available from Aldrich Chemical); matrix soluble derivatives of silicon phthalocyanine (as described in Rodgers, AJ. et al., 107 J. Phys. Chem. A 3503-3514, May 8, 2003), and matrix soluble derivatives of benzophthalocyanines (as described in Aoudia, Mohamed, 119 J. Am. Chem. Soc. 6029-6039, July 2, 1997); phthalocyanine compounds such as those described in U.S. Patent Nos. 6,015,896 and 6,025,486, which are each incorporated herein by reference; and Cirrus 715 (a phthalocyanine dye available from Avecia, Manchester, England having an A_max = 806 nm).

In another embodiment, laser light having blue and indigo wavelengths from about 300 nm to about 400 nm can be used to develop the color forming compositions. Therefore, the present disclosure can provide color forming compositions optimized within a range for use in devices that emit wavelengths within this range. Recently developed commercial lasers found in certain DVD and laser disk recording equipment provide for energy at a wavelength of about 405 nm. Thus, using appropriate radiation-absorbing compound can be suited for use with components that are already available on the market or are readily modified to accomplish imaging. Radiation-absorbing compounds that can be useful for optimization in the blue (about 405nm) and indigo wavelengths can include, but are not limited to, aluminum quinoline complexes, porphyrins, porphins, and mixtures or derivatives thereof. Non-limiting specific examples of suitable radiation antenna can include 1-(2-chloro-5-sulfophenyl)-3-methyl-4-(4- sulfophenyl)azo-2-pyrazolin-5-one disodium salt (X max = 400 nm); ethyl 7- diethylaminocoumarin-3-carboxylate (X max = 418 nm); 3,3'-diethylthiacyanine ethylsulfate (X max = 424 nm); 3-allyl-5-(3-ethyl-4-methyl-2-thiazolinylidene) rhodanine (X max = 430 nm) (each available from Organica Feinchemie GmbH Wolfen), and mixtures thereof. Non-limiting specific examples of suitable aluminum quinoline complexes can include tris(8-hydroxyquinolinato)aluminum (CAS 2085-33-8) and derivatives such as tris(5-cholor-8- hydroxyquinolinato)aluminum (CAS 4154-66-1), 2-(4-(1-methyl-ethyl)-phenyl)-6- phenyl-4H-thiopyran-4-ylidene)-propanedinitril-1,1 -dioxide (CAS 174493-15-3), 4,4'-[1 ,4-phenylenebis(1 ,3,4-oxadiazole-5,2-diyl)]bis N,N-diphenyl benzeneamine (CAS 184101-38-0), bis-tetraethylammonium-bis(1 ,2-dicyano-dithiolto)-zinc(ll) (CAS 21312-70-9), 2-(4,5-dihydronaphtho[1 ,2-d]-1 ,3-dithiol-2-ylidene)-4,5- dihydro-naphtho[1 ,2-d]1 ,3-dithiole, all available from Syntec GmbH. Non-limiting examples of specific porphyrin and porphyrin derivatives can include etioporphyrin 1 (CAS 448-71-5), deuteroporphyrin IX 2,4 bis ethylene glycol (D630-9) available from Frontier Scientific, and octaethyl porphrin (CAS 2683-82- 1), azo dyes such as Mordant Orange CAS 2243-76-7, Merthyl Yellow (60-11-7), 4-phenylazoaniline (CAS 60-09-3), Alcian Yellow (CAS 61968-76-1), available from Aldrich chemical company, and mixtures thereof.

Examples of antenna dyes suitable for imaging with 780 nm laser radiations include, but are not limited to: a) IR-780 iodide, (Aldrich 42,531-1) (1) (3H-lndolium, 2-[2-[2-chloro-3- [(I.S-dihydro-S.S-dimethyl-i-propyl^H-indol^-ylideneJethylidenel-i-cyclohexen- 1 -yl]ethenyl]-3,3-dimethyl-1 -propyl-, iodide(9CI)), b) IR783 (Aldrich 54,329-2) (2) (2-[2-[2-Chloro-3-[2-[1 ,3-dihydro-3,3- dimethyl-1 -(4-sulfobutyl)-2H-indol-2-ylidene]-ethylidene]-1 -cyclohexen-1 -yl]- ethenyl]-3,3-dimethyl-1-(4-sulfobutyl)-3H-indoliumhydroxide, inner salt sodium salt). c) 3H-lndolium, 2-[2-[2-chloro-3-[(1 ,3-dihydro-1 ,3,3-trimethyl-2H-indol-2- ylidene)ethylidene]-1-cyclopenten-1-yl]ethenyl]-1,3,3-trimethyl-, salt with 4- methylbenzenesulfonic acid (1 :1) (9Cl) -(Lambda max - 797nm). CAS No. 193687-61-5. Available from "Few Chemicals GMBH" asS0337. d) 3H-lndolium, 2-[2-[3-[(1 ,3-dihydro-1 ,3,3-trimethyl-2H-indol-2- ylidene)ethylidene]-2-[(1-phenyl-1H-tetrazol-5-yl)thio]-1-cyclohexen-1-yl]ethenyl]- 1 ,3,3-trimethyl-, chloride (9Cl). (Lambda max -798nm). CAS No. 440102-72-7. Available from "Few Chemicals GMBH" as S0507. e) 1 H-Benz[e]indolium, 2-[2-[2-chloro-3-[(1 ,3-dihydro-1 ,1 ,3-trimethyl-2H- benztelindol^-ylideneJethylidenel-i-cyclohexen-i-yllethenylJ-I .I .S-trimethyl-, chloride (9Cl) (Lambda max - 813nm). CAS No. 297173-98-9. Available from "Few Chemicals GMBH" as S0391. f) 1 H-Benz[e]indolium, 2-[2-[2-chloro-3-[(1 ,3-dihydro-1 ,1 ,3-trimethyl-2H- benz[e]indol-2-ylidene) ethylidene]-1-cyclohexen-1-yl]ethenyl]-1 ,1 ,3-trimethyl-, salt with 4-methylbenzenesulfonic acid (1:1) (9Cl) (Lambda max - 813nm). CAS No. 134127-48-3. Available from "Few Chemicals GMBH" as S0094. Also known as Trump Dye or Trump IR. g) 1 H-Benz[e]indolium, 2-[2-[2-chloro-3-[(3-ethyl-1 ,3-dihydro-1 ,1-dimethyl- 2H-benz[e]indol-2-ylidene)ethylidene]-1 -cyclohexen-1 -yl]ethenyl]-3-ethyl-1 , 1 - dimethyl-, salt with 4-methylbenzenesulfonic acid (1 :1) (9Cl) (Lambda max - 816nm). CAS No. 460337-33-1. Available from "Few Chemicals GMBH" as S0809.

In addition, the radiation absorbing compound can include phthalocyanine or naphthalocyanine IR dyes such as Silicon 2,3-naphthalocyanine bis (trihexylsiloxide) (CAS No. 92396-88-8) (Lambda max - 775nm).

The radiation-absorbing compound is from about 0.01 wt% to 10 wt% of the imaging layer and from about 0.1 wt% to 3 wt% of the imaging layer.

Having summarized embodiments, reference will now be made in detail to the illustrative Examples. While the disclosure is described in connection with the Examples, there is no intent to limit the embodiments of the disclosure to the following example. On the contrary, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope of the disclosure. Example 1 :

The following is an illustrative example of an embodiment of the present disclosure where there was no white powder formation after 48 hours in 60° C environmental oven. The lacquer (also referred to as the "matrix") component of the coating is made up of:

Matrix A: about 60 wt% isobornyl acrlyate, about 30 wt% n-butyl carbamide acrylate, and about 10 wt% tricyclodecane dimethonal diacrylate. Coating Components: The coating components are about 49 wt% of matrix A, about 25 wt%

Leuco-dye, about 15 wt% activator, about 7 wt% UV-initiator package, about 3 wt% IR- absorbing antenna, and about 1 wt% surface additive. In a similar example, the isobornyl acrlyate is reduced to about 28 wt %, with the balance redistributed into the formulation in a relative manner.

Example 2:

Matrix B: about 60 wt% trimethylcyclohexane acrylate, or dihydrodicyclo- pentadienyl acrylate, or adamantly (meth)acrylate; about 30 wt% n-butyl carbamide acrylate; and about 10 wt% tricyclodecane dimethonal diacrylate. Coating Components:

The coating components are about 49 wt% of matrix B, about 25 wt% Leuco-dye, about 15 wt% activator, about 7 wt% UV-initiator package, about 3 wt% IR- absorbing antenna, and about 1 wt% surface additive.

Example 3:

Matrix C: about 55 wt% isobornyl acrylate; about 25 wt% n-butyl carbamide acrylate; about 10 wt% tricyclodecane dimethonal diacrylate; about 2 wt% bisphenol-A diacrylate; and about 8 wt% lacquer-soluble polymer like Paraloid ™ A-11 , B60,

B66, B80, or DM55. Coating Components: The coating components are about 49 wt% of matrix C, about 25 wt%

Leuco-dye, about 15 wt% activator, about 7 wt% UV-initiator package, about 3 wt% IR- absorbing antenna, and about 1 wt% surface additive.

Example 4: The following is an illustrative example of an embodiment of the present disclosure where there was white powder formation after 48 hours in 60° C environmental oven. The lacquer (also referred to as the "matrix") component of the coating is made up of: Matrix D: about 55 wt% hexanedioldiacrylate; about 25 wt% n-butyl carbamide acrylate; about 10 wt% tricyclodecane dimethonal diacrylate; about 2 wt% bisphenol-A diacrylate; and about 8 wt% lacquer-soluble polymer like Paraloid ™ A-11 , B60, B66, B80, or DM55. Coating Components:

The coating components are about 49 wt% of matrix D, about 25 wt% Leuco-dye, about 15 wt% activator, about 7 wt% UV-initiator package, about 3 wt% IR- absorbing antenna, and about 1 wt% surface additive.

Example 5:

The following is an illustrative example of an embodiment of the present disclosure where there was white powder formation but slightly less than Example 4 after 48 hours in 60° C environmental oven. The lacquer (also referred to as the "matrix") component of the coating is made up of: Matrix E: about 20 wt% isobornyl acrylate; about 35 wt% hexanedioldiacrylate; about 25 wt% n-butyl carbamide acrylate; about 10 wt% tricyclodecane dimethonal diacrylate; about 2 wt% bisphenol-A diacrylate; and about 8 wt% lacquer-soluble polymer like Paraloid ™ A-11 , B60, B66, B80, or DM55. Coating Components:

The coating components are about 49 wt% of matrix E, about 25 wt% Leuco-dye, about 15 wt% activator, about 7 wt% UV-initiator package, about 3 wt% IR- absorbing antenna, and about 1 wt% surface additive.

Example 6:

The following is an illustrative example of an embodiment of the present disclosure where there was white powder formation but noticeably less than Example 4 and 5 after 48 hours in 60° C environmental oven. The lacquer (also referred to as the "matrix") component of the coating is made up of: Matrix F: about 28 wt% isobornyl acrylate; about 27 wt% hexanedioldiacrylate; about 25 wt% n-butyl carbamide acrylate; about 10 wt% tricyclodecane dimethonal diacrylate; about 2 wt% bisphenol-A diacrylate; and about 8 wt% lacquer-soluble polymer like Paraloid ™ A-11 , B60,

B66, B80, or DM55. Coating Components:

The coating components are about 49 wt% of matrix F, about 25 wt% Leuco-dye, about 15 wt% activator, about 7 wt% UV-initiator package, about 3 wt% IR- absorbing antenna, and about 1 wt% surface additive. Example 7:

The following is an illustrative example of an embodiment of the present disclosure where white powder formation was substantially less than Example 6 but not less than Example 1 , 2, or 3 after 48 hours in 60° C environmental oven. The lacquer (also referred to as the "matrix") component of the coating is made up of: Matrix G: about 45 wt% isobornyl acrylate; about 10 wt% hexanedioldiacrylate; about 25 wt% n-butyl carbamide acrylate; about 10 wt% tricyclodecane dimethonal diacrylate; about 2 wt% bisphenol-A diacrylate; and about 8 wt% lacquer-soluble polymer like Paraloid ™ A-11 , B60, B66, B80, or DM55. Coating Components: The coating components are about 49 wt% of matrix G, about 25 wt%

It should be noted that ratios, concentrations, amounts, and other numerical data may be expressed herein in a range format. It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a concentration range of "about 0.1% to 5%" should be interpreted to include not only the explicitly recited concentration of about 0.1 wt% to about 5 wt%, but also include individual concentrations (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within the indicated range. The term "about" can include ±1 %, ±2%, ±3%, ±4%, ±5%, ±6%, ±7%, ±8%, ±9%, or ±10%, or more of the numerical value(s) being modified. In addition, the phrase "about 'x' to 'y'" includes "about 'x' to about 'y'". The above discussion is meant to be illustrative of the principles and various embodiments of the present disclosure. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.

Claims

What is claimed is: 1. An optical disk comprising: a substrate having a first side and a second side, wherein the first side stores digital data, wherein the second side includes an imaging layer, wherein the imaging layer is formulated to substantially eliminate or eliminate white powder formation up to temperatures of about 60° C, wherein the imaging layer includes: a matrix including a monoacrylate and a diacrylate, wherein the monoacrylate is greater than about 30 wt% of the imaging layer, wherein the diacrylates is less than about 10 wt% of the imaging layer, wherein the monoacrylate is selected from isobornyl acrylate, N-butylcarbamide acrylate, or a combination thereof, wherein the diacrylate is tricyclodecanedimethanol diacrylate; a radiation-absorbing compound; an activator; and a color former.

2. The optical disk of claim 1 , wherein the monoacrylate is isobornyl acrylate and is greater than about 20 wt% of the imaging layer.

3. The optical disk of claim 1 , wherein the monoacrylate is isobornyl acrylate and is greater than about 25 wt% of the imaging layer.

4. The optical disk of claim 1 , wherein the monoacrylate is isobornyl acrylate and is greater than about 30 wt% of the imaging layer.

5. The optical disk of claim 1 , wherein the diacrylate is tricyclodecanedimethanol diacrylate and is less than about 10 wt% of the imaging layer.

6. The optical disk of claim 1 , wherein the diacrylate is tricyclodecanedimethanol diacrylate and is less than about 8 wt% of the imaging layer.

7. The optical disk of claim 1 , wherein the diacrylate is tricyclodecanedimethanol diacrylate and is less than about 6 wt% of the imaging layer.

8. The optical disk of claim 1 , wherein the optical disk is selected from a compact disk (CD), a digital video disk (DVD), a DVD-HD, and a DVD BIu- ray.

9. The optical disk of claim 1 , wherein the optical disk has an optical disk format for encoding digital data that is selected from one the following: DVD-HD, Blu-ray, DVD, DVD-R, DVD-RW, DVD+R, DVD+RW, DVD-

RAM, CD, CD-ROM, CD-R, and CD-RW.

10. The optical disk of claim 1 , further comprising hexanedioldiacrylate, wherein hexanedioldiacrylate is less than about 5 wt% of the imaging layer.

11. The optical disk of claim 1 , wherein matrix includes isobornyl acrylate and N-butylcarbamide acrylate.

12. A method for preparing an optical disk including an imaging layer, the method comprising: providing a matrix including a monoacrylate and a diacrylate, wherein the monoacrylate is greater than about 30 wt% of the imaging layer, wherein the diacrylates is less than about 6 wt% of the imaging layer, wherein the monoacrylate is selected from isobornyl acrylate, isobornyl acrylate, N-butylcarbamide acrylate, or a combination thereof, wherein the diacrylate is tricyclodecanedimethanol diacrylate; mixing the radiation-absorbing compound, the activator, and the color former, in the matrix to form a matrix mixture; and disposing the matrix mixture onto a substrate to form the imaging layer, wherein the imaging layer is formulated to substantially eliminate or eliminate white powder formation up to temperatures of about 60° C.

13. The method of claim 12, wherein the optical disk is selected from a compact disk (CD), a digital video disk (DVD), a DVD-HD, and a DVD BIu- ray.

14. The method of claim 12, wherein the optical disk stores digital data.

15. The method of claim 12, wherein the optical disk has an optical disk format to encode digital data that is selected from one the following: DVD-HD, Blu-ray, DVD, DVD-R, DVD-RW, DVD+R, DVD+RW, DVD-RAM, CD, CD-

ROM, CD-R, and CD-RW.

16. The method of claim 12, wherein the monoacrylate is isobornyl acrylate and is greater than about 20 wt% of the imaging layer.

17. The method of claim 12, wherein the monoacrylate is isobornyl acrylate and is greater than about 25 wt% of the imaging layer.

18. The method of claim 12, wherein the monoacrylate is isobornyl acrylate and is greater than about 30 wt% of the imaging layer.

19. The method of claim 12, wherein the diacrylate is tricyclodecanedimethanol diacrylate and is less than about 10 wt% of the imaging layer.

20. The method of claim 12, wherein the diacrylate is tricyclodecanedimethanol diacrylate and is less than about 8 wt% of the imaging layer.

21. The method of claim 12, wherein the diacrylate is tricyclodecanedimethanol diacrylate and is less than about 6 wt% of the imaging layer.

22. The method of claim 12, further comprising hexanedioldiacrylate, wherein hexanedioldiacrylate is less than about 5 wt% of the imaging layer.

23. The method of claim 12, wherein the matrix includes isobornyl acrylate and N-butylcarbamide acrylate.