Patent Application
20060292326
The present invention relates to the use of an axially substituted Co phthalocyanine as light-absorbent compound in the light-writable information layer of write-once optical data carriers, to optical data carriers and to a process for producing them.
The write-once compact disk (CD-R) has recently experienced enormous volume growth. The light-absorbent compound of the information layer of such a disk is an important component of the optical data carrier which has to meet demanding and wide-ranging requirements. The preparation of such compounds is not infrequently correspondingly demanding (cf. WO-A-02/080162).
It is therefore an object of the invention to provide further light-absorbent compounds for CD-R formats, in particular ones which are environmentally friendly and are simple to synthesize and which satisfy the high requirements (e.g. light stability, favourable signal/noise ratio, high writing sensitivity, damage-free application to the substrate material, and the like), for use as light-absorbent compound in the information layer of write-once optical data carrier (predominantly CD-R).
It has surprisingly been found that Co phthalocyanines having an axial substituent and an axial coordinated ligand are very useful for the stated purpose.
The present invention accordingly provides optical data carriers whose information layer comprises at least one light-absorbent compound which is a Co(III) phthalocyanine in which the Co metal centre bears an axial substituent R1 and an axial coordinated ligand R2, where R1 is CN, SCN, halogen, in particular Cl, Br or F, alkoxy, aryloxy, arylthio or alkylthio and R2 is no ligand or substituted or unsubstituted amine, water, an alcohol, H2S, a thioalcohol or an isonitrile.
The optical data carrier can preferably be written on and read by means of infrared light, preferably laser light, in particular light having a wavelength in the range 750-800 nm, especially 770-790 nm.
Preference is likewise given to optical data carriers comprising a preferably transparent substrate which may, if desired, have previously been coated with one or more reflection layers and to whose surface a light-writable information layer, if desired one or more reflection layers and if desired a protective layer or a further substrate or a covering layer have been applied, which can be written and read by means of infrared light, preferably laser light, particularly preferably light having a wavelength in the range 750-800 nm, especially 770-790 nm, where the information layer comprises a light-absorbent compound and, if desired, a binder, characterized in that at least one Co(III) phthalocyanine in which the Co metal centre bears an axial substituent R1 and an axial coordinated ligand R2, where R1 is CN, SCN, halogen, alkoxy, aryloxy, arylthio or alkylthio and R2 is no ligand or NR17R1 R19, OR10R11, SR10R11 or an isonitrile of the formula
where the substituents are as defined below, is used as light-absorbent compound.
As light-absorbent compound, preference is given to using a Co phthalocyanine of the formula (I)
where
The alkyl, alkoxy, aryl and heterocyclic radicals may, if desired, bear further radicals such as halogen, hydroxy, hydroxyalkyl, amino, alkylamino, dialkylamino, nitro, cyano, CO—NH2, alkoxycarbonyl, morpholino, piperidino, pyrrolidino, trialkylsilyl or trialkylsiloxy. The alkyl and alkoxy radicals may additionally bear aryl radicals and aryl radicals may additionally bear alkyl or alkoxy radicals. The alkyl and alkoxy radicals can be saturated, unsaturated, linear or branched, the alkyl radicals may be partially halogenated or perhalogenated and the alkyl and alkoxy radicals may be ethoxylated or propoxylated or silylated. Adjacent alkyl and/or alkoxy radicals on aryl or heterocyclic radicals may together form a three- or four-membered bridge.
Preference is given to compounds of the formula (I) in which the radicals R1 to R8 and R, R′, R″ and R9 to R12 and R17 to R19 are:
substituents of the “alkyl” type, preferably C1-C16-alkyl, in particular C1-C6-alkyl, which may be substituted by halogen such as chlorine, bromine, fluorine, hydroxy, cyano and/or C1-C6-alkoxy;
substituents of the “alkoxy” type, preferably C1-C16-alkoxy, in particular C1-C6-alkoxy, which may be substituted by halogen such as chlorine, bromine, fluorine, hydroxy, cyano and/or C1-C6-alkyl;
substituents of the “cycloalkyl” type, preferably C4-C8-cycloalkyl, in particular C5-C6-cycloalkyl, which may be substituted by halogen such as chlorine, bromine or fluorine, hydroxy, cyano and/or C1-C6-alkyl.
Substituents of the “alkenyl” type, preferably C6-C8-alkenyl, which may be substituted by halogen such as chlorine, bromine or fluorine, hydroxy, cyano and/or C1-C6-alkyl, with particular preference being given to alkenyl being allyl;
substituents of the “hetaryl” type, preferably heterocyclic radicals having 5- to 7-membered rings, which preferably contain heteroatoms from the group consisting of N, S and/or O and may be fused with aromatic rings or may bear further substituents, for example halogen, hydroxy, cyano and/or alkyl, with particularly preferred heteraryl radicals being: pyridyl, furyl, thienyl, oxazolyl, thiazolyl, imidazolyl, quinolyl, benzoxazolyl, benzothiazolyl or benzimidazolyl;
substituents of the “aryl” type, preferably C6-C10-aryl, in particular phenyl or naphthyl, which may be substituted by halogen, e.g. F, Cl, hydroxy, C1-C6-alkyl, C1-C6-alkoxy, NO2 and/or CN.
Preference is given to Co phthalocyanines of the formula (I) in which
R1 is CN, SCN, chlorine, fluorine, bromine, iodine, alkoxy or alkylthio,
R2 is no ligand or NR17R18R19, OR10R11, SR10R11 or an isonitrile of the formula
R is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, tert-amyl, hydroxyethyl, 3-dimethylaminopropyl, 3-diethylaminopropyl, phenyl, p-tert-butylphenyl, p-methoxyphenyl, isopropylphenyl, trifluoromethylphenyl, benzyl or naphthyl,
For the purposes of the present patent application, redox systems are, in particular, the redox systems described in Angew. Chem. 1978, p. 927, and in Topics of Current Chemistry, Vol. 92, p. 1 (1980).
Preference is given to p-phenylenediamine, phenothiazine, dihydrophenazine, bipyridinium salts (viologens), quinodimethane.
Preference is given to Co phthalocyanines of the formula (I) in which the sum of w, x, y and z is greater than zero, preferably from 1 to 12.
Very particular preference is given to novel compounds of the formula Ia
where
The invention further provides compounds of the formula (Ia) in which the respective substituents are as defined above.
The invention also provides a process for preparing compounds of the formula (Ia), which is characterized in that substituted or unsubstituted Co phthalocyanine is oxidized, subsequently reacted with KatCN, KatSCN, Kat halide, Kat alkoxide or Kat alkylthiolate and, if desired the product is reacted further with NR17R18R19, OR10R11, SR10R11 or an isonitrile of the formula
at a temperature of 30-100° C., in particular 40-70° C.,
where
The introduction of the axial substituents is preferably carried out under oxidative conditions, e.g. chlorine or air, preferably air, in the case of air in the presence of excess KatCN, KatSCN, Kat alkoxide or Kat alkylthiolate and the optional introduction of the further axial ligands is carried out by means of NR17R18R19, OR10R11, SR10R11 or an isonitrile of the formula
at a temperature of 20-80° C., in particular 40-60° C.
The invetion further provides mixtures containing at least 1-50% by weight, preferably more than 80% by weight, in particular more than 90% by weight, of a Co(III) phthalocyanine of the formula I having an axial substituent R1, and an axial ligand R2, where R1 is CN, SCN, halogen, alkoxy, aryloxy, arylthio or alkylthio, and R2 is no ligand or NR17R18R9, OR10R11, SR10R11 or an isonitrile of the formula
A further constituent of the mixture is preferably a phthalocyanine different from the formula I. In particular, this is a phthalocyanine of the formula II,
where R1, R3, R4, R5, R6 w, x, y, z and CoPc are as defined above and
The mixture particularly preferably contains from 0 to 50% by weight of the dye of the formula (II), in particular from 0 to 20%, more preferably less than 10% by weight.
Particular preference is given to more than 95% by weight, in particular more than 98% by weight, of the mixture being made up of the two dyes I and II.
The light-writable information layer particularly preferably comprises, as light-absorbent compounds, a Co(III) phthalocyanine compound as described above, in particular one of the formula I, together with at least one other substituted or unsubstituted phthalocyanine with or without a central atom. Possible central atoms in this phthalocyanine are, for example, atoms from the group consisting of Si, Zn, Al, Cu, Pd, Pt, Au and Ag, in particular Cu and Pd.
The invention also provides mixtures comprising:
The respective preferred embodiments indicated above are preferred for each of the components a) and b).
As component b), particular preference is given to, for example, the sulphonamide-substituted Cu phthalocyanines known from DE-A 19 925 712. Particular preference is given to those of the formula III
where
Particularly preferred mixture components c) are compounds of the formula (III) which correspond to the formula (IIIa)
CuPc—[SO2NH—CH2CH2CH2N(CH2)3 (IIIa),
where
CuPc is copper phthalocyanine.
Further preferred additional light-absorbent compounds are the sulphonamide- or amido-substituted phthalocyanines known, for example, from EP-A-519 395.
In the case of mixtures of various light-absorbent compounds, the proportion of the compounds of the formula (I) in the mixture is preferably from 10 to 90% by weight.
Particular preference is given to a mixture of the formulae (I) and (III) in a weight ratio of from 10:90 to 90:10, preferably from 20:80 to 80:20, particularly preferably from 40:60 to 60:40.
The information layer can comprise not only the light-absorbent compound but also binders, wetting agents, stabilizers, diluents and sensitizers and also further constituents.
The substrates can have been produced from optically transparent plastics which, if necessary, have undergone a surface treatment. Preferred plastics are polycarbonates and polyacrylates, and also polycycloolefins or polyolefins.
The reflection layer can have been produced from any metal or metal alloy which is customarily utilised for writable optical data carriers. Suitable metals and metal alloys can be applied by vapour deposition and sputtering and comprise, for example, gold, silver, copper, aluminium and their alloys with one another or with other metals.
The possible protective layer over the reflection layer can comprise UV-curing acrylates.
A possible intermediate layer which protects the reflection layer, for example against oxidation, can likewise be present.
The invention further provides a process for producing the optical data store of the invention, characterized in that a Co(III) phthalocyanine in which the Co metal centre bears an axial substituent R1 and an axial coordinated ligand R2, where R1 is CN, SCN, halogen, in particular Cl, Br or F, alkoxy, aryloxy, arylthio or alkylthio and R2 is no ligand or a substituted or unsubstituted amine, water, an alcohol, H2S, a thioalcohol or an isonitrile, is applied as light-absorbent compound to the substrate of the optical data carrier.
Preference is given to a process for producing the optical data carrier of the invention, which is characterized in that the light-writable information layer is applied to a transparent substrate by coating with at least one Co phthalocyanine complex of the formula I, if desired in combination with other light-absorbent compounds, in particular compounds of the component b), suitable binders, additives and solvents, and, if desired, the coated substrate is additionally provided with a reflection layer, if desired further intermediate layers and if desired a protective layer.
The coating of the substrate with the light-absorbent compound of the formula I, if desired in combination with further dyes, binders and/or solvents, is preferably carried out by spin coating or sputtering.
For the coating procedure, the light-absorbent compound, in particular the compound of the formula I, is preferably dissolved with or without additives in a suitable solvent or solvent mixture so that the compound, in particular that of the formula I, is present in an amount of 100 parts by weight or less, for example from 10 to 20 parts by weight, per 100 parts by weight of solvent. The writable information layer is then preferably metallized under reduced pressure by sputtering or vapour deposition (reflection layer) and then provided, if desired, with a protective surface coating (protective layer) or a further substrate or a covering layer. Multilayer arrangements with a partially transparent reflection layer are also possible.
The solvents or solvent mixtures for the application of the light-absorbent compounds of the formula I or their mixtures with additives and/or binders and also other light-absorbent compounds are selected, firstly, according to their solvent capacity for the light-absorbent compound, in particular that of the formula I, and the other additives and, secondly, so as to have a minimal influence on the substrate. Suitable solvents which have little influence on the substrate are, for example, alcohols, ethers, hydrocarbons, halogenated hydrocarbons, alkoxy alcohols, ketones. Examples of such solvents are methanol, ethanol, propanol, 2,2,3,3-tetrafluoropropanol, butanol, in particular 1-butanol, nonanol, in particular 1-nonanol, diacetone alcohol, benzyl alcohol, tetrachloroethane, dichloromethane, diethyl ether, dipropyl ether, dibutyl ether, methyl tert-butyl ether, methoxyethanol, ethoxyethanol, 1-methyl-2-propanol, methyl ethyl ketone, 4-hydroxy-4-methyl-2-pentanone, hexane, cyclohexane, ethylcyclohexane, octane, benzene, toluene, xylene. Preferred solvents are hydrocarbons and alcohols since they have the smallest influence on the substrate. Particular preference is given to propanol, 2,2,3,3-tetrafluoropropanol, butanol and mixtures of these alcohols with diacetone alcohol or nonanol, in particular 1-nonanol, particularly preferably propanol/diacetone alcohol 80-100%/0-20%.
Suitable additives for the writable information layer are stabilizers, wetting agents, binders, diluents and sensitizers.
The light-absorbent compound should preferably be able to be changed thermally. The thermal change preferably occurs at a temperature of <600° C. Such a change can be, for example, a decomposition or chemical change of the chromophoric centre of the light-absorbent compound.
Apart from the information layer, further layers such as metal layers, dielectric layers and protective layers may be present in the optical data store. Metals and dielectric layers serve, inter alia, to adjust the reflectivity and the heat absorption/retention. Metals can be, depending on the laser wavelength, gold, silver, aluminium, etc. Examples of dielectric layers are silicon dioxide and silicon nitride. Protective layers are, for example, photocurable surface coatings, (pressure-sensitive) adhesive layers and protective films.
Pressure-sensitive adhesive layers consist mainly of acrylic adhesives. Nitto Denko DA-8320 or DA-8310, disklosed in the patent JP-A 11-273147, can, for example, be used for this purpose.
The optical data carrier has, for example, the following layer structure (cf
The structure of the optical data carrier preferably:
Alternatively, the optical data carrier has, for example, the following layer structure (cf.
Alternatively, the optical data carrier has, for example, the following layer structure (cf.
The invention further provides optical data carriers according to the invention which have been written on by means of blue, red or infrared light, in particular laser light, especially infrared laser light.
The following examples illustrate the subject matter of the invention.
The following preparative examples demonstrate the preparation of the dyes to be used according to the invention.
113 g of cobalt tetra-(2,4-dimethyl-3-pentoxy)phthalocyanine (isomer mixture) are stirred overnight at room temperature (RT) with 15.63 g of KCN in 1 l of NMP. 162 g of silica gel are then added, the mixture is stirred for 1 hour and filtered with suction. The NMP solution is slowly added dropwise to a mixture of 810 g of NaCl with 2.5 l of water and ice. After stirring for 2 hours at RT, the mixture is filtered with suction and the paste is stirred in water/methanol 1:1 at 40° C. for 1 hour. After cooling, the solid is filtered off with suction and dried at 30° C. under reduced pressure. Yield: 100.6 g of dye of the formula:
80 g of cobalt tetra-(2,4-dimethyl-3-pentoxy)phthalocyanine (isomer mixture) are stirred overnight at RT with 14.6 g of KCN in 800 ml of propanol while passing air through the mixture. 162 g of silica gel are then added, the mixture is stirred for another 1 hour and filtered with suction. The propanol solution is admixed with 320 ml of NMP, the propanol is distilled off and the remaining NMP solution is slowly added dropwise to a mixture of 150 g of NaCl with 1.5 l of water and ice. After stirring at RT for 1 hour, the mixture is filtered with suction and the paste is washed with 1 l of water/methanol 1:1. The paste is stirred with 1 l of water, the solid is once again filtered off with suction and dried at 40° C. under reduced pressure. Yield: 60.6 g of dye of the formula:
120 g of cobalt tetra-(2-ethylhexoxy)phthalocyanine (isomer mixture) are stirred with 15 g of KCN in 111 of NMP at RT. 162 g of silica gel are then added, the mixture is stirred for 1 hour and filtered with suction. The NMP solution is slowly added dropwise to a mixture of 6500 g of NaCl with 2 l of water and ice. After 2 hours at RT, the mixture is filtered with suction and the paste is stirred in water/methanol 1:1 at 40° C. for 1 hour. After cooling, the solid is filtered off with suction and dried at 30° C. under reduced pressure. Yield: 105 g of dye of the formula:
The dye from Example 2 was brought into solution at room temperature. The solution concentration was 20 g of dye per litre of solvent. The solvent consisted of 97% by mass of 1-propanol and 3% by mass of 1-nonanol. This solution was applied by means of spin coating to a pregrooved polycarbonate substrate. The pregrooved polycarbonate substrate had been produced as a disk by means of injection molding. The dimensions of the disk corresponded to those customarily used for CD-Rs. The groove depth and groove width were 200 nm and 730 nm, respectively. The disk with the dye layer as information carrier was coated with 100 nm of silver by vapour deposition. A UV-curable acrylic coating composition was subsequently applied by spin coating and cured by means of a UV lamp.
The finished disk was tested in a CD-R testing apparatus (Plustec OMT 2000×4) which is provided with a diode laser having a wavelength of λ=787 nm. Particularly attention was paid to the track following signal PPb and the groove reflectivity Rgb, since these two signals are critical for the disk to be accepted in a burner. The following measured values were obtained: PPb=0.089; Rgb=0.754.
Using a method analogous to Example 4, the following disks were prepared and tested:
| Number | Date | Country | Kind |
|---|---|---|---|
| 102536104 | Nov 2002 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP03/12280 | 11/4/2003 | WO | 10/12/2005 |
