Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
1998-02-03
2002-07-02
Yamnitzky, Marie (Department: 1774)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S917000, C313S504000, C252S301160, C252S301340, C252S301350
Reexamination Certificate
active
06413655
ABSTRACT:
The present invention relates to a composition comprising (a) an effective amount of a guest chromophore embedded in a matrix of a host chromophore, or (b) a host chromophore and an effective amount of a guest chromophore both embedded in a polymer matrix, wherein the absorption spectrum of the guest chromophore overlaps with the fluorescence emission spectrum of the host chromophore, and wherein the host chromophore is selected from the group consisting of benzo [4,5] imidazo [2,1-a] isoindol-11-ones.
Further, the present invention relates to a process for the preparation of this composition, a polymerisable composition comprising this composition, a composition comprising a carrier material with a high relief of a polymerized photoresist material containing this composition, a process for the preparation of fluorescent high relief images on a carrier, the use of the compositions as fluorescent materials, especially in electroluminescent devices, and novel non-functionalized benzo[4,5]imidazo[2,1-a]isoindol-11-one derivatives.
Combinations comprising host chromophores with guest chromophores dissolved therein to generate materials with enhanced fluorescence and large differences between absorption maximum and emission maximum are highly desired materials that possess a wide range of potential and actual technical applications. The large difference between the absorption (excitation) maximum and the emission maximum is due to the occurrence of resonant energy transfer between the respective host and guest chromophores.
The possibility of energy transfer between chromophores that possess an area of overlap of the absorption spectrum of a guest chromophore with the fluorescence emission spectrum of a host is known. For example, H. Port et al. describe in Z. Naturforsch., 36a, pages 697 to 704 (1981) mixed crystals of fluorene doped with dibenzofurane or benzindan with an enhanced fluorescence in the UV region at temperatures below 100 K. However, the low temperature fluorescence has no practical value and is only of scientific interest.
C. W. Tang et al. disclose in J. Appl. Phys., 65, 3610 to 3616 (1989) a multilayered electroluminescent device with a light emitting layer composed of 8-hydroxyquinoline aluminum, in which is embedded a zone doped with a fluorescent molecule such as coumarin. The device shows improved electroluminescence and an effective Stoke's color shift which is dependent on the particular dopant. The manufacture of the device is complicated and not readily suitable for an industrial production.
J. M. Lang et al. describe in J. Phys. Chem. 97, pages 5058 to 5064 (1993) the combination of coumarin as host and rhodamine as guest whereby both components are dissolved in polyacrylic acid, but Lang's study demonstrates enhanced fluorescence only under high pressure.
In WO 93/23492 are disclosed fluorescent microparticles with an enhanced Stokes shift, which are composed of soluble and fluorescent host and guest dyes absorbed or bonded to polymeric microparticles. The material is used for the optical detection of nucleic acids like DNA or RNA. Unfavorably, the solid state fluorescence of these microparticles is poor.
U.S. Pat. No. 5,227,252 discloses a fluorescent composition of 8-hydroxyquinoline aluminum as host and quinacridones as guest. Similarly, JP-A-05 320 633 discloses a fluorescent composition of 8-hydroxyquinoline aluminum as host and diketopyrrolopyrroles as guest. However, in both documents, the guests are insoluble materials, they are dissolved mainly as microsized clusters. The occurrence of microsized clusters is due to co-sublimation processes being the means of preparation. The materials possess a larger Stoke's shifts than would be anticipated by normal single component fluorescent materials, and are used for example as light emitting materials in electroluminescent devices. The process for their manufacture requires large expenditures on technical equipment to ensure the careful control process conditions such as vacuum and temperature, to achieve the desired mixed material. The process is not convenient for large scale industrial manufacture.
In EP-A-0 456 609 is disclosed a process for the preparation of 1,2,3,4-tetrachlorobenzo[4,5] imidazo[2,1-a]isoindol-11-one and its derivatives in the presence of selected solvents. These compounds are pigments showing solid state fluorescence and improved outdoor durability. It is also mentioned therein, that the combination of 95% of the yellow 1,2,3,4-tetrachloro-benzo[4,5] imidazo[2,1-a]isoindol-11-one with 5% of Indanthrone Blue generates a green fluorescent pigment. Hence, such a system is a pigment composite, wherein the new color generated is simply a sum of the two component colors. The color is not created by virtue of the occurrence of complex, molecular level, energy transfer processes that require close interaction between the components of the mixture.
F. W. Harris et.al. describe in ACS Symp. Ser. 132, 39 (1980) the compound 1,2,3,4-tetraphenyl-benzo [4,5] imidazo [2,1-a] isoindol-11-one as a model material, as a part of their investigations into phenylated polyimidazopyrrolones for potential use in aerospace applications. However, no reference to its fluorescence behavior is made.
Hence, the object of the invention on hand was to find a fluorescent composition, which does not show the above mentioned disadvantages, preferably a composition should be provided which
has a greatly enhanced and intense fluorescence emission,
shows an intense solid state fluorescence, wherein the emission spectrum is preferably in the visible region of the electromagnetic spectrum,
is excitable using wavelengths in both the UV and visible regions,
shows a very excellent photostability and outdoor durability,
shows a wide range of emission spectra through selection of suited guest molecules (color tuning),
has a high thermal stability,
is easily prepared, i.e. by a (co-)precipitation process,
can be used for the preparation of electroluminescence devices,
if the host chromophore is selected from the group consisting of benzo[4,5]imidazo[2,1-a]isoindol-11-ones, which means derivatives of benzo[4,5]imidazo[2,1-a]isoindol-11-one as the fundamental substance.
In addition, the enhancement factor for the present compositions preferably should be all positive and should be at least 1.3, more preferably at least 2 and most preferably at least 5. The term “enhancement factor” as used herein, is defined as the increased or decreased factor, in terms of peak height emission intensities of a solid-state powder comprising of host and guest fluorescent moieties compared to an identical powder that does not contain any fluorescent guest moieties. Comparisons are considered real, for as long as the excitation radiation wavelengths are identical. In general, the emission wavelengths of host/guest material occur at longer wavelengths (lower energy) as compared to an identical material with no guest component.
Accordingly, a composition was found comprising (a) an effective amount of a guest chromophore embedded in a matrix of a host chromophore, or (b) a host chromophore and an effective amount of a guest chromophore both embedded in a polymer matrix, wherein the absorption spectrum of the guest chromophore overlaps with the fluorescence emission spectrum of the host chromophore, and wherein the host chromophore is selected from the group consisting of benzo[4,5]imidazo [2,1-a] isoindol-11-ones.
In addition, a process for the preparation of this composition, a polymerizable composition comprising this composition, a composition comprising a carrier material with a high relief of a polymerized photoresist material containing this composition, a process for the preparation of fluorescent high relief images on a carrier, the use of the compositions as fluorescent materials, esp. in electroluminescent devices, and novel non-functionalized benzo[4,5]imi
Deno Takashi
Devlin Brian Gerrard
Kodama Kunihiko
Kunimoto Kazuhiko
Otani Junji
Ciba Specialty Chemicals Corporation
Crichton David R.
Yamnitzky Marie
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