Diacetylene film sensitized with photoinitiator and applications of the film
A process for improving sensitivity of a film base, coated with a dispersion of a normally crystalline polyacetylenic compound in a non-solvating liquid which is dried on the film surface, to particular photon energy band, specifically, long wavelength UV; the polyacetylenic compound preferably having at least two conjugated acetylenic linkages and containing from 12 to 60 carbon atoms. The sensitization of the film to long wavelength UV is achieved via the addition of photoinitiator(s) capable of absorbing UV energy and converting it to free radicals.
1. A film media sensitive to long wavelength UV comprising a first support layer of polymeric film which is permeable to said UV and a second layer prepared from a radiochromic active fluid comprising a microcrystalline dispersion of a substantially crystalline image receptive polyacetylenic compound and a photoinitiator compound or mixture of photoinitiators,
wherein said photoinitiator compound(s) are selected from the group consisting of sodium salt of anthraquinone-2-sulfonic acid, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone and 2-hydroxy-2-methylpropiophenone.
2. The film media of claim 1 , wherein the polyacetylenic compound has the following structure:
A-(CH 2 ) n —C≡C—C≡C—(CH 2 )m-B:
wherein m and n are both independently an integer from 6 to 14 and A and B are independent from one another and are selected from the group consisting of methyl, carboxyl, hydroxy, amido, lower alkyl substituted amido, aliphatic or aromatic carboxylate ester group having up to 10 carbon atoms, mono- or di-valent carboxylate metal salt group, halo, carbamyl, lower alkyl substituted carbamyl or tosyl, triyn or tetrayne products of the above polyacetylenes having from 20 to 60 carbon atoms and a conjugated structure, and combinations thereof.
3. The film media of claim 1 , wherein the photoinitiator compound is present in an amount from about 0.01 to 10.0% by weight of the radiochromic active fluid.
4. The film media of claim 1 , wherein the long wavelength UV has wavelength in the range between 280 to 400 nm.
5. The film media of claim 1 , wherein the photoinitiator is present in an amount from about 0.05 to 1.0% by weight of the radiochromic active fluid.