Titanyl phthalocyanin crystal, method for preparing the same and electrophotographic photoconductor

Abstract

According to the present invention, a titanyl phthalocyanin crystal excellent in storage stability in organic solvents, a method for preparing the same and an electrophotographic photoconductor using the same are provided. In the titanyl phthalocyanin crystal, the method for preparing such a titanyl phthalocyanin crystal and the electrophotographic photoconductor using the same, the titanyl phthalocyanin crystal is characterized by having the maximum peak at a Bragg angle 2θ±0.2°=27.2° in a CuKα characteristic X-ray diffraction spectrum and one peak within the range of 270 to 400° C. other than a peak accompanied by the vaporization of adsorbed water in a differential scanning calorimetric analysis.

1 . A titanyl phthalocyanin crystal having the maximum peak at a Bragg angle 2θ±0.2°=27.2° in a CuKα characteristic X-ray diffraction spectrum and one peak within the range of 270 to 400° C. other than a peak accompanied by the vaporization of adsorbed water in a differential scanning calorimetric analysis.  
   
   
       2 . The titanyl phthalocyanin crystal according to  claim 1 , wherein the titanyl phthalocyanin crystal has no peak at a Bragg angle 2θ±0.2°=26.2° in the CuKα characteristic X-ray diffraction spectrum.  
   
   
       3 . The titanyl phthalocyanin crystal according to  claim 1 , wherein the titanyl phthalocyanin crystal recovered after being immersing for 7 days in an organic solvent has at least the maximum peak at a Bragg angle 2°±0.2°=27.2° and no peak at 26.2° in the CuKα characteristic X-ray diffraction spectrum.  
   
   
       4 . The titanyl phthalocyanin crystal according to  claim 3 , wherein a organic solvent is at least one selected from the group consisting of tetrahydrofuran, dichloromethane, toluene, 1,4-dioxane and 1-methoxy-2-propanol.  
   
   
       5 . The titanyl phthalocyanin crystal according to  claim 1 , wherein the structure of titanyl phthalocyanin compounds is represented by the following general formula (1).  
     
       
         
         
             
             
         
       
     
     (In the general formula (1), X 1  to X 4  are the same or different substituents, each independently represents a hydrogen atom, a halogen atom, a substituted or an unsubstituted alkyl group, a substituted or an unsubstituted alkoxy group, a substituted or an unsubstituted cyano group or a substituted or an unsubstituted nitro group, respectively, the repeat number “a”, “b”, “c” and “d” represent an integer of 1 to 4, respectively and may be same or different, respectively.)  
   
   
       6 . A method for preparing a titanyl phthalocyanin crystal having the maximum peak at a Bragg angle 2θ±0.2°=27.2° in a CuKα characteristic X-ray diffraction spectrum and one peak within the range of 270 to 400° C. other than a peak accompanied by the vaporization of adsorbed water in a differential scanning calorimetric analysis and comprising the following processes (a) and (b); 
 (a) a process for preparing a titanyl phthalocyanin compound by adding a titanium alkoxide or titanium tetrachloride at a value within the range of 0.40 to 0.53 mole with respect to 1 mole of o-phthalonitrile or its derivative or 1,3-diiminoisoindoline or its derivative and adding a urea compound at a value within the range of 0.1 to 0.95 mole with respect to 1 mole of o-phthalonitrile or its derivative or 1,3-diiminoisoindoline or its derivative to react the compounds,    (b) a process for preparing a titanyl phthalocyanin crystal by performing an acid treatment on the titanyl phthalocyanin compound prepared in the process (a).    
   
   
       7 . The method for preparing the titanyl phthalocyanin crystal according to  claim 6 , wherein the urea compound is at least one compound selected from the group consisting of urea, thiourea, o-methylisourea sulfate, o-methylisourea carbonate and o-methylisourea hydrochloride.  
   
   
       8 . The method for preparing the titanyl phthalocyanin crystal according to  claim 6 , wherein the reaction temperature in the process (a) is set to a value of 150° C. or above.  
   
   
       9 . The method for preparing the titanyl phthalocyanin crystal according to claims  6 , wherein the process (a) is performed in a nitrogen-containing compound with a boiling point of 180° C. or above.  
   
   
       10 . An electrophotographic photoconductor having a photosensitive layer is provided on a conductive substrate, wherein the photosensitive layer contains the titanyl phthalocyanin crystal having the maximum peak at a Bragg angle 2θ±0.2°=27.2° in the CuKα characteristic X-ray diffraction spectrum and one peak within the range of 270 to 400° C. other than a peak accompanied by the vaporization of adsorbed water in the differential scanning calorimetric analysis, within the range of 0.1 to 50 part by weight with respect to 100 part by weight of a binder resin forming the photosensitive layer.