Patent Number: 056419678
Section: description

EXAMPLES 1-3 AND THE COMPARATIVE EXAMPLE Image storage panels were prepared by the following general procedure. Phosphor BaFBr.sub..85 I.sub..15: 0.001Eu.sup.2+ (99.00 grams) and oxosulfur functionalized polymer reducing agent (1.00 gram) were dispersed in a 13 (weight/weight)% solution of PERMUTHANE.TM. U-6366 polyurethane marketed by ICI Polyurethanes Group of West Deptford, N.J. in 93:7 (weight/weight) dichloromethane/methanol solvent. The phosphor to conventional binder ratio was 15:1. Knife-coatings were prepared on a polyethylene terephthalate support. The knife-coatings were allowed to air-dry to produce luminescent layers. After drying the completed storage panels were overcoated with a polymer solution of cellulose acetate in acetone. A Comparative Example image storage panel was prepared in an identical manner, except that no amount of oxosulfur functionalized polymer reducing agent was added. The oxosulfur functionalized polymer reducing agent for Example 1 was Polymer .alpha.. The oxosulfur functionalized polymer reducing agent for Example 2 was Polymer .beta. and the oxosulfur functionalized polymer reducing agent for Example 3 was Polymer .chi.. The relative photostimulated luminescence (PSL) intensities of the image storage panels were measured by cutting 2.6 centimeter diameter disks from the panels, and simultaneously exposing the sample and the Comparative Example to filtered X-radiation. The X-ray source was a tungsten target tube operating at 70 kVp and 3.0 mA. The filtration consisted of a 3.5 centimeter thickness of aluminum. After exposure to X-rays, the samples and Comparative Example were stimulated with a 4-millisecond pulse at 633 nanometers from a 12 mW helium-neon laser. The stimulated emission was detected using a photomultiplier tube after passing through a Schott BG-25 filter. The responses were corrected for X-ray exposure variations by normalizing the measured response in each case to an internal standard. The PSL responses for the Examples are reported relative to the Comparative Example handled in an identical manner. The response of the Comparative Example in each case was arbitrarily set equal to 100. The measured PSL responses were corrected for variations in phosphor coverage by dividing by the coverage value determined for that particular disk. The oxosulfur functionalized polymer reducing agents used to make the image storage panels of Examples 1 to 3 and the PSL responses for Examples 1 to 3 and the Comparative Example are listed in Table 1. From Table 1, it is observed that the addition of oxosulfur functionalized polymer reducing agents to panels containing BaFBr.sub..85 I.sub..15 :0.001Eu.sup.2+ phosphor improves the photostimulated luminescence of the resulting radiographic phosphor panel. TABLE 1 ______________________________________ Effect of Oxosulfur Functionalized Polymer Reducing Agents on the PSL of Radiographic Phosphor Panels. Oxosulfur Functionalized Example Polymer Reducing Response Agent PSL ______________________________________ 1 polymer .alpha. 174 2 polymer .beta. 168 3 polymer .chi. 182 Comparative none 100 Example ______________________________________