CA1284493C - Pigments and photoconductive elements sensitive to infrared radiation - Google Patents
Pigments and photoconductive elements sensitive to infrared radiationInfo
- Publication number
- CA1284493C CA1284493C CA000536714A CA536714A CA1284493C CA 1284493 C CA1284493 C CA 1284493C CA 000536714 A CA000536714 A CA 000536714A CA 536714 A CA536714 A CA 536714A CA 1284493 C CA1284493 C CA 1284493C
- Authority
- CA
- Canada
- Prior art keywords
- charge
- layer
- bromoindium
- photoconductive
- methyl
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
- G03G5/02—Charge-receiving layers
- G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
- G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
- G03G5/0664—Dyes
- G03G5/0696—Phthalocyanines
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
- C09B47/00—Porphines; Azaporphines
- C09B47/04—Phthalocyanines abbreviation: Pc
- C09B47/06—Preparation from carboxylic acids or derivatives thereof, e.g. anhydrides, amides, mononitriles, phthalimide, o-cyanobenzamide
- C09B47/073—Preparation from isoindolenines, e.g. pyrrolenines
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
- C09B67/00—Influencing the physical, e.g. the dyeing or printing properties of dyestuffs without chemical reactions, e.g. by treating with solvents grinding or grinding assistants, coating of pigments or dyes; Process features in the making of dyestuff preparations; Dyestuff preparations of a special physical nature, e.g. tablets, films
- C09B67/0001—Post-treatment of organic pigments or dyes
- C09B67/0014—Influencing the physical properties by treatment with a liquid, e.g. solvents
- C09B67/0016—Influencing the physical properties by treatment with a liquid, e.g. solvents of phthalocyanines
Abstract
PIGMENTS AND PHOTOCONDUCTIVE ELEMENTS
SENSITIVE TO INFRARED RADIATION
Abstract of the Disclosure A novel C-centered monoclinic bromoindium phthalocyanine pigment is obtained by reacting high=
purity diiminoisoindoline with indium tribromide in the solvent, 1-methyl-2-pyrrolidinone. Multiactive photoconductive elements prepared by dispersion=
coating a charge-generation layer containing this pigment have high sensitivity to near-infrared radia-tion.
SENSITIVE TO INFRARED RADIATION
Abstract of the Disclosure A novel C-centered monoclinic bromoindium phthalocyanine pigment is obtained by reacting high=
purity diiminoisoindoline with indium tribromide in the solvent, 1-methyl-2-pyrrolidinone. Multiactive photoconductive elements prepared by dispersion=
coating a charge-generation layer containing this pigment have high sensitivity to near-infrared radia-tion.
Description
~L284493 PIGMENTS AND PHOTOCONDUCTIVE ELEMENTS
SENSITIVE TO INFRARED RADIATION
Field of the Invention Thls invention relates to novel pigments and 5 photoconductive elements containing them. In par-ticular, it relates to such elements which are sensi-tive to radiation in the infrared region of the spec-trum and to a novel phthalocyanine photoconductive pigment and a method of preparing the pigment.
10 BackRround of the Invention Photoconductive elements are composed of a conducting support having a photoconductive layer which is insulating in the dark but which becomes conductive upon exposure to actinic radiation. To form images, the surface of the element is electro-statically and uniformly charged in the dark and then exposed to a pattern of actinic radiation. In areas where the photoconductive layer ~8 irradiated, moblle charge carrlers are generated whlch mlgrate to the 20 surface and dlssipate the surface chsrge. This leaves in nonirradlated areas a charge pattern, referred to as a latent electrostatic image. The latent image can be developed, either on the surface on which it is formed or on another surface to which it is transferred, by application of a liquid or dry developer contalning flnely dlvided charged toner particles.
Numerous photoconductors have been described as being useful in electrophotography. These include inorganic substances, such as selenium and zinc oxlde, and organlc compounds, both monomeric and polymeric, such as arylamines, arylmethane~, azoles, carbazoles, pyrroles, phthalocyanines and the like.
Photoconductlve elements can comprise single 35 or multiple active layers. Those with multiple active layers (sometimes called multiactive elements) '~84a~3 have at least one chsrge-generation layer snd st lesst one charge-transport layer. Under actinic radiation, the charge-generation layer generates mobile chsrge carriers snd the charge-transport layer facilltstes migrstion of the charge csrriers to the surface of the element, where they dissipate the uni-form electrostatic charge snd form the latent elec-troststic image.
The ms~ority of known photoconductors sre 10 sensitive to ultrsviolet and visible electromsgnetic radiation. However, increasing use is beinB made of diode lasers which emit radistion principally in the near-infrsred region of the electromagnetic spectrum, i.e., from 700 nm to about 900 nm. Known photocon-ductors either have little or no sensitivity to suchrsdistion, or they hsve other disadvsntages. For example, they msy become incressingly conductive in the dsrk and lose thelr sbility to hold sn electro-ststic charge (a proces~ known as dark decay), or they may have poor quantum efficiency which results in low electrophotogr~phic sensitivity, or they msy require an extremely high electroststic chsrge or other extreme conditions.
There is, therefore, a need for photoconduc-tive elements sensitive to the nesr-infrsred region of the electromsgnetic spectrum snd having low dark decay and high sensitivity.
Borsenberger et al in U. S. Patent 4,471,039 hsve disclosed thst when the ~-phsse of sn indium 30 phthslocysnine pigment is used as the charge=
generstion lsyer in a multisctive electrophotogrsphic element, the element hss high sensitivity in the near-infrared region.
Although the phthslocysnine pigments dis-closed by Borsenberger et al hsve high infrared ~en-sitivity and low dark decay, it has been preferred to ~34g~93 purify them by a sublimation in order to obtain high speed and low dark decay, a purification step which can be costly.
Brief SummarY of the Invention In accordance with the present invention, a method ls provided for preparing phthalocyanine pig-ments of even higher infrared sensitivity and lower dark decay which do not require purification by sub-limation. In addition, the invention provides a 10 novel crystalline form of bromoindium phthalocyanine and an improved photoconductive element containing this type of pigment.
The method of the invention comprises react-ing high purity diiminoisoindoline with indium bro-15 mide in a reaction solvent comprising l-methyl-2-pyr-rolidinone and recovering bromoindiumphthalocyanine pigment.
The novel pigment is a C-centered monoclinic bromoindium phthalocyanine having x-ray diffractogram 20 ma~or peaks at Bragg diffraction angles (2e) of 7.4, 16.7, 25.3, 27.5 and 28.4.
The photoconductive element of the invention comprises an electrically conductive support and a photoconductive layer containing a bromoindium 25 phthalocyanine pigment of the novel species.
Although the photoconductive elements of the inven-tion include single-layer elements, i.e., having a single active layer, in a preferred embodlment the element is a multiactive photoconductive element com-30 prising an electrically conductive support, a charge=
generation layer and a charge-transport layer. The invention provides an improvement wherein the charge=
generation layer comprises dispersion-coated bromoin-dium phthalocyanine pigment of the novel species.
The identification of the pigment a~ being C-centered monoclinic refers to the unit cell of the ~ 28~3 three-dimensional crystalline lattice and has a com-monly understood meaning as disclosed, for example, in Structure Determination bv X-RaY CrYstalloRraPhY
by Ladd and Palmer tl977). page 59, Plenum Publishers.
The Drawin~s In describing the invention reference will be made to the drawings of which the sole figure is an X-ray diffractogram of intensity vs. Bragg angle (2e) for a charge-generation layer containing a bro-10 moindium phthalocyanine in accordance with the inven-tion.
Detailed DescriPtion of the Invention a) ProPerties and PreParation of the Bromoindium Phthalocvanine The bromoindium phthalocyanine pigment pre-pared by the method of the invention is a C-centered, monoclinic indium phthalocyanine with surprisingly high electrophotographic sensitivity to radiation in the near-infrared region and low dark decay. It i~
20 also of such high purity that lt can be coated on a conductive element from a liquid dispersion instead of requiring vapor deposition on the support to achieve adequate purity.
In accordance with the invention, the pig-25 ment is prepared by reacting high purity diiminoiso-indoline with indium bromide in l-methyl-2-pyrrolidi-none as the solvent, as shown by the following:
NH
~ C~ l-methyl-2-pyrrolidinone / ~C~ InBr3 NH
Diiminoisoindoline ~2~34~93 Bromoindium Phthalocyanine In this reaction, it is important that the diiminoisoindoline be of high purity, e.g., of a 15 purity of 99 weight percent or higher. One method of obtaining the reagent in such high purity is to syn-thesize it by the reaction of phthalonitr~le with ammonia in a lower alkanol solvent and in the pres-snce of an alkali metal alkanoate, as in the ~ollow-ing reactlon:
NH
~-~ /CN CH30H .~
~ CN NH3 _ ~ ¦ IJ /NH
NH
Phthalonitrile Diiminoisoindoline The phthalonitrile Rhould also be of high purity, e.g., 99 weight percent or higher. Recrys-tallization from ethyl acetate yields the desired purity.
It has been discovered ln accordance with the present invention that, when the diiminoisoindo-~2~34~93 line is used in such high purity, it is unnecessaryto purify the resulting bromoindium phthalocyanine by the expensive sublimation process used in prior-art preparations.
~, b) Pre~aration of the Photoconductive Element To prepsre a ~ingle-layer photoconductive element of the invention, the described bromoindium phthalocyanine is solvent-coated on an electrically conductive support at a thickness, for example, in 10 the range from about 0.05 to 10 ~m.
Multiactive photoconductive elements of the invention include not only a charge-generating layer containing the phthalocyanine pigment, but also one or more charge-transport layers. In such multiactive 15 elements, the charge-~enerating layer can have a thickness withirl a wide range, depending upon the degree of photosensitivity desired. Thickness affects photosensitivity ln two opposite ways. As thickness increases, a greater proportion of incident 20 radiation i~ absorbed by the layer, but there is a greater likelihood of a charge carrier being trapped and thus not contributing to image formation. These two factors must be balanced. A thickness in the range of about 0.05 ~m to 5 ~m provides maximum 25 photosensitivity. At thicknesses much below 0.05 ~m there is inadequate absorption of actinic radiatlon whereas, at thicknesses much above 5 ~m, there is excessive trapping of charge carriers.
The charge-trsnsport layers can be comprised 30 of any material, organic or inorganic, which can transport charge carriers. Most charge-transport materials preferentially accept and transport either positive charges (holes) or negative charges (elec-trons), although materials are known which will transport both positive and negative charges. Those exhibiting a preference for conduction of positive charge carriers are called p-type transport materials and those exhibiting ~ preference for the conduction of negative charges are called n-type.
Various p-type organic compounds can be used in the charge-transport layer such as:
1. Carbazoles including carbazole, N-ethyl car-bazole, N-isopropyl carbazole, N-phenyl carbazole, halogenated carbazoles, various polymeric carbazole materials such as poly(vinyl carbazole), halogenated lO poly(vinyl carbazole) and the like.
SENSITIVE TO INFRARED RADIATION
Field of the Invention Thls invention relates to novel pigments and 5 photoconductive elements containing them. In par-ticular, it relates to such elements which are sensi-tive to radiation in the infrared region of the spec-trum and to a novel phthalocyanine photoconductive pigment and a method of preparing the pigment.
10 BackRround of the Invention Photoconductive elements are composed of a conducting support having a photoconductive layer which is insulating in the dark but which becomes conductive upon exposure to actinic radiation. To form images, the surface of the element is electro-statically and uniformly charged in the dark and then exposed to a pattern of actinic radiation. In areas where the photoconductive layer ~8 irradiated, moblle charge carrlers are generated whlch mlgrate to the 20 surface and dlssipate the surface chsrge. This leaves in nonirradlated areas a charge pattern, referred to as a latent electrostatic image. The latent image can be developed, either on the surface on which it is formed or on another surface to which it is transferred, by application of a liquid or dry developer contalning flnely dlvided charged toner particles.
Numerous photoconductors have been described as being useful in electrophotography. These include inorganic substances, such as selenium and zinc oxlde, and organlc compounds, both monomeric and polymeric, such as arylamines, arylmethane~, azoles, carbazoles, pyrroles, phthalocyanines and the like.
Photoconductlve elements can comprise single 35 or multiple active layers. Those with multiple active layers (sometimes called multiactive elements) '~84a~3 have at least one chsrge-generation layer snd st lesst one charge-transport layer. Under actinic radiation, the charge-generation layer generates mobile chsrge carriers snd the charge-transport layer facilltstes migrstion of the charge csrriers to the surface of the element, where they dissipate the uni-form electrostatic charge snd form the latent elec-troststic image.
The ms~ority of known photoconductors sre 10 sensitive to ultrsviolet and visible electromsgnetic radiation. However, increasing use is beinB made of diode lasers which emit radistion principally in the near-infrsred region of the electromagnetic spectrum, i.e., from 700 nm to about 900 nm. Known photocon-ductors either have little or no sensitivity to suchrsdistion, or they hsve other disadvsntages. For example, they msy become incressingly conductive in the dsrk and lose thelr sbility to hold sn electro-ststic charge (a proces~ known as dark decay), or they may have poor quantum efficiency which results in low electrophotogr~phic sensitivity, or they msy require an extremely high electroststic chsrge or other extreme conditions.
There is, therefore, a need for photoconduc-tive elements sensitive to the nesr-infrsred region of the electromsgnetic spectrum snd having low dark decay and high sensitivity.
Borsenberger et al in U. S. Patent 4,471,039 hsve disclosed thst when the ~-phsse of sn indium 30 phthslocysnine pigment is used as the charge=
generstion lsyer in a multisctive electrophotogrsphic element, the element hss high sensitivity in the near-infrared region.
Although the phthslocysnine pigments dis-closed by Borsenberger et al hsve high infrared ~en-sitivity and low dark decay, it has been preferred to ~34g~93 purify them by a sublimation in order to obtain high speed and low dark decay, a purification step which can be costly.
Brief SummarY of the Invention In accordance with the present invention, a method ls provided for preparing phthalocyanine pig-ments of even higher infrared sensitivity and lower dark decay which do not require purification by sub-limation. In addition, the invention provides a 10 novel crystalline form of bromoindium phthalocyanine and an improved photoconductive element containing this type of pigment.
The method of the invention comprises react-ing high purity diiminoisoindoline with indium bro-15 mide in a reaction solvent comprising l-methyl-2-pyr-rolidinone and recovering bromoindiumphthalocyanine pigment.
The novel pigment is a C-centered monoclinic bromoindium phthalocyanine having x-ray diffractogram 20 ma~or peaks at Bragg diffraction angles (2e) of 7.4, 16.7, 25.3, 27.5 and 28.4.
The photoconductive element of the invention comprises an electrically conductive support and a photoconductive layer containing a bromoindium 25 phthalocyanine pigment of the novel species.
Although the photoconductive elements of the inven-tion include single-layer elements, i.e., having a single active layer, in a preferred embodlment the element is a multiactive photoconductive element com-30 prising an electrically conductive support, a charge=
generation layer and a charge-transport layer. The invention provides an improvement wherein the charge=
generation layer comprises dispersion-coated bromoin-dium phthalocyanine pigment of the novel species.
The identification of the pigment a~ being C-centered monoclinic refers to the unit cell of the ~ 28~3 three-dimensional crystalline lattice and has a com-monly understood meaning as disclosed, for example, in Structure Determination bv X-RaY CrYstalloRraPhY
by Ladd and Palmer tl977). page 59, Plenum Publishers.
The Drawin~s In describing the invention reference will be made to the drawings of which the sole figure is an X-ray diffractogram of intensity vs. Bragg angle (2e) for a charge-generation layer containing a bro-10 moindium phthalocyanine in accordance with the inven-tion.
Detailed DescriPtion of the Invention a) ProPerties and PreParation of the Bromoindium Phthalocvanine The bromoindium phthalocyanine pigment pre-pared by the method of the invention is a C-centered, monoclinic indium phthalocyanine with surprisingly high electrophotographic sensitivity to radiation in the near-infrared region and low dark decay. It i~
20 also of such high purity that lt can be coated on a conductive element from a liquid dispersion instead of requiring vapor deposition on the support to achieve adequate purity.
In accordance with the invention, the pig-25 ment is prepared by reacting high purity diiminoiso-indoline with indium bromide in l-methyl-2-pyrrolidi-none as the solvent, as shown by the following:
NH
~ C~ l-methyl-2-pyrrolidinone / ~C~ InBr3 NH
Diiminoisoindoline ~2~34~93 Bromoindium Phthalocyanine In this reaction, it is important that the diiminoisoindoline be of high purity, e.g., of a 15 purity of 99 weight percent or higher. One method of obtaining the reagent in such high purity is to syn-thesize it by the reaction of phthalonitr~le with ammonia in a lower alkanol solvent and in the pres-snce of an alkali metal alkanoate, as in the ~ollow-ing reactlon:
NH
~-~ /CN CH30H .~
~ CN NH3 _ ~ ¦ IJ /NH
NH
Phthalonitrile Diiminoisoindoline The phthalonitrile Rhould also be of high purity, e.g., 99 weight percent or higher. Recrys-tallization from ethyl acetate yields the desired purity.
It has been discovered ln accordance with the present invention that, when the diiminoisoindo-~2~34~93 line is used in such high purity, it is unnecessaryto purify the resulting bromoindium phthalocyanine by the expensive sublimation process used in prior-art preparations.
~, b) Pre~aration of the Photoconductive Element To prepsre a ~ingle-layer photoconductive element of the invention, the described bromoindium phthalocyanine is solvent-coated on an electrically conductive support at a thickness, for example, in 10 the range from about 0.05 to 10 ~m.
Multiactive photoconductive elements of the invention include not only a charge-generating layer containing the phthalocyanine pigment, but also one or more charge-transport layers. In such multiactive 15 elements, the charge-~enerating layer can have a thickness withirl a wide range, depending upon the degree of photosensitivity desired. Thickness affects photosensitivity ln two opposite ways. As thickness increases, a greater proportion of incident 20 radiation i~ absorbed by the layer, but there is a greater likelihood of a charge carrier being trapped and thus not contributing to image formation. These two factors must be balanced. A thickness in the range of about 0.05 ~m to 5 ~m provides maximum 25 photosensitivity. At thicknesses much below 0.05 ~m there is inadequate absorption of actinic radiatlon whereas, at thicknesses much above 5 ~m, there is excessive trapping of charge carriers.
The charge-trsnsport layers can be comprised 30 of any material, organic or inorganic, which can transport charge carriers. Most charge-transport materials preferentially accept and transport either positive charges (holes) or negative charges (elec-trons), although materials are known which will transport both positive and negative charges. Those exhibiting a preference for conduction of positive charge carriers are called p-type transport materials and those exhibiting ~ preference for the conduction of negative charges are called n-type.
Various p-type organic compounds can be used in the charge-transport layer such as:
1. Carbazoles including carbazole, N-ethyl car-bazole, N-isopropyl carbazole, N-phenyl carbazole, halogenated carbazoles, various polymeric carbazole materials such as poly(vinyl carbazole), halogenated lO poly(vinyl carbazole) and the like.
2. Arylamines including monoarylamines, diaryl-amines, triarylamines and polymeric arylamines. Spe-cific arylamine organic photoconductors include the nonpolymeric trlphenylamines illustrated in Klupfel 15 et al U. S. Patent 3,180,730 issued April 27, 1965;
the polymeric triarylamines described in Fox U.S.
Patent 3,240,597 issued March 15, 1966; the triaryl-amines having at least one of the aryl radicals sub-~tituted by either 8 vinyl radical or a vinylene 20 radical having at least one active hydrogen3 containing group, as described in Brantly et al U.S.
Patent 3,567,450 issued March 2, 1971; the triaryl-amines in which at least one of the aryl radicals is substituted by an active hydrogencontaining group, as 25 described by Brantly et al U.S. Patent 3,658,520 issued April 25, 1972; and tritolylamine.
the polymeric triarylamines described in Fox U.S.
Patent 3,240,597 issued March 15, 1966; the triaryl-amines having at least one of the aryl radicals sub-~tituted by either 8 vinyl radical or a vinylene 20 radical having at least one active hydrogen3 containing group, as described in Brantly et al U.S.
Patent 3,567,450 issued March 2, 1971; the triaryl-amines in which at least one of the aryl radicals is substituted by an active hydrogencontaining group, as 25 described by Brantly et al U.S. Patent 3,658,520 issued April 25, 1972; and tritolylamine.
3. Polyarylalkanes of the type described in Noe et al U.S. Patent 3,274,000 issued September 20, 1966, Wilson U.S. Patent 3,542,547 issued November 30 24, 1970, and Rule et al U.S. Patent 3,615,402 issued October 26, 1971. Preferred polyarylalkane photocon-ductors are of the formula:
J-C-E
G
~ 2 8 : -8-wherein:
D ~nd G, which may be the same or different, represent aryl groups and J and E, which may be the sQme or dlfferent, represent 8 hydrogen ~tom, an S alkyl group, or an aryl group, at least one of D, E
and ~ containing an amino ~ubstituent. An e~pecially useful ch~rge-transport material is Q polyarylalkane wherein J and E represent hydrogen, aryl or alkyl ~nd D and G represent ~ubstituted aryl groups having as a 10 substituent thereof ~ group of the formula:
15 wherein:
R is unsubstituted aryl such as phenyl or alkyl-sub~tituted aryl such as a tolyl group. Ex~m-ples of such polyarylalkanes may be found ln Rule et al U.S. Patent 4,127,412 i~sued November 28, 1978.
J-C-E
G
~ 2 8 : -8-wherein:
D ~nd G, which may be the same or different, represent aryl groups and J and E, which may be the sQme or dlfferent, represent 8 hydrogen ~tom, an S alkyl group, or an aryl group, at least one of D, E
and ~ containing an amino ~ubstituent. An e~pecially useful ch~rge-transport material is Q polyarylalkane wherein J and E represent hydrogen, aryl or alkyl ~nd D and G represent ~ubstituted aryl groups having as a 10 substituent thereof ~ group of the formula:
15 wherein:
R is unsubstituted aryl such as phenyl or alkyl-sub~tituted aryl such as a tolyl group. Ex~m-ples of such polyarylalkanes may be found ln Rule et al U.S. Patent 4,127,412 i~sued November 28, 1978.
4 Strong Lewi~ bs~es ~uch as arom~tlc com-pounds, includlng aromatlcally unsaturated heterocy-cllc compounds free from strong electron-withdrawlng groups. Examples include tetraphenylpyrene, l-meth-ylpyrene, perylene, chry~ene, anthracene, tetraphene, 2-phenyl naphthalene, azapyrene, fluorene, fluore-none, l-ethylpyrene, acetyl pyrene, 2,3-benzochrys-ens, 3,4-benzopyrene, 1,4-bromopyrene, phenylindole, polyvinyl carbazole, polyvinyl pyrene, polyvinyltet-racene, polyvinyl perylene ~nd polyvinyl tetraphene.
5. Hydrazones including the dialkyl=
~ubstituted aminobenzaldehyde-(diphenylhydrazones) of U.S. P~tent 4,150,987 lssued April 24, 1979; alkylhy-drazones and arylhydrazones as described in U.S. Pat-ents 4,554,231, is~ued November 19, 1985; 4,487,824, issued December 11, 1984; 4,481,271, issued November 6, lg84; 4,456,671, i~sued June 26, 1984; 4,446,217, ~.28~d~93 _9_ issued May 1, 1984; and 4,423,129, issued December 27, 1983, which are illustrative of the p-type hydra-zones.
Other useful p-type charge transports ~re 5 the p-type photoconductors described in Research Dis-closure, Vol. 109, May, 1973, pages 61-67, paragraph IV (A) (2) through (13).
Representative of n-type charge transports are strong Lewis acids such as organic, including 10 metallo-organic, compounds containing one or more aromatic, including aromatically unsaturated hetero-cyclic, groups bearing an electron-withdrawing sub-stituent. These are useful because of their electron-accepting capability. Typical electron=
15 withdrawing substituents include cyano and nitro;
sulfonate; halogens such as chlorine, bromine and iodine; ketone groups; ester groups; acid anhydride groups; and other acid groups ~uch as carboxyl and quinone groups. Representative n-type aromatic 20 Lewis acids having electron-withdraw~ng substituents lnclude phthalic anhydride, tetrachlorophthalic anhy-dride, benzil, mellitlc anhydride, S-tricyanobenzene, picryl chloride, 2,4-dinitrochlorobenzene, 2,4-dini-trobromobenzene, 4-nitrobiphenyl, 4,4-dinitrobi-25 phenyl, 2,4,6-trinitroanisole, trichlorotrinitroben-zene, trinitro-o-toluene, 4,6-dichloro-1,3-dinitro-benzene, 4,6-dibromo-1,3-dinitrobenzene, ~-dinltro-benzene, chloranil, bromanil, 2,4,7-trinitro-9-fluo-renone, 2,4,5,7-tetranitrofluorenone, trinitroanthra-30 cene, dinitroacridine, tetracyanopyrene, dinitroan-thraquinone, and mixtures thereof.
Other u~eful n-type charge transports are conventional n-type organic photoconductors, for example, complexes of 2,4,6-trinitro-9-fluorenone and poly(vinyl carbazole). Still others are the n-type photoconductors described in Research Disclosure, ~8~93 Vol. 109, May, 1973, pages 61-67, paragraph IV(A) (2) through (13).
A single charge-transport layer or more than one can be employed. Where a slngle charge-transport layer is employed, it can be either a p-type or an n-type substance.
In one useful configuration, the charge=
generation layer is between the conducting support and a charge-transport layer or layers. This 10 arrangement provides flexibility and permits control of the physical and surface characteristics of the element by the nature of the charge-transport layer.
In another useful configuration, called the inverted multilayer configuration, the charge=
transport layer is between the conducting support and the charge-generation layer, the latter containing the phthalocyanine pigment of the present invention.
If the charge-generstion layer is to be exposed to actlnic radiation through the charge=
transport layer, it is preferred that the charge=
transport layer have little or no absorption in the region of the electromagnetic spectrum to which the charge-generation layer responds, thus permitting the maximum smount of actinic radiation to reach the 25 charge-generation layer. Where the charge-transport layer is not in the path of exposure, this does not apply.
Each of the charge-generation and charge=
transport layers is applied by solvent-coating the 30 active component in an electrically insulating film=
forming polymeric binder. The optimum ratio of charge-generation or charge-transport compound to binder can vary widely. In general, useful results are obtained when the amount of active chargez 35 generation or charge-transport compound within the 4~3 layer varies from about 5 to 90 weight percent based on the dry weight of the layer.
Binders in the charge-generation and charge=
transport layers are film-forming polymers having a fairly high dielectric strength and good electrically insulating properties. Examples include butadiene copolymers; polyvinyl toluene-styrene copolymers;
styrene-~lkyd resins; ~il$cone-alkyd resins; soya=
alkyd resins; vinylldene chloride-vinyl chloride 10 copolymers; poly(vinylidene chloride); vinylidene chloride-acrylonitrile copolymers; vinyl acetate=
vinyl chloride copolymers; poly(vinyl acetals) such as poly(vinyl butyral); nitrated polystyrene; poly-methylstyrene; i~obutylene polymers; polyesters such 15 a~ poly[ethylene-coalkylenebis(alkyleneoxyaryl)-phenylenedicarboxylate]; phenol formaldehyde resins;
ketone resins; polyamides; polycarbonates, polythio-carbonates; poly[ethylene-co-isopropylidene-2,2-bis-(ethyleneoxyphenylene)terephthalate]; copolymers of 20 vinyl haloacrylates and vinyl acetate such as poly-(vinyl-m-bromobenzoate-co-vinyl acetflte); chlorinated poly(olefins) such as chlorinated poly(ethylene), etc..
Polymers containing aromatic or heterocyclic 25 groups are most effective as binders because they provide little or no interference with the transport of charge carrier~ through the layer. Heterocyclic or aromatic containing polymers which are especially useful in p-type charge-transport layers include 30 styrene-containing polymers, bisphenol A polycarbon-ate polymers, phenol formaldehyde resins, polyesters such as poly[ethylene-co-isopropylidene2,2-bis-(eth-yleneoxy-phenylene)]terephthalate, and copolymers of vinyl haloacrylates and vinyl acetate such aq poly-(vinyl-m-bromobenzoate-co-vinyl acetate).
~8~g3 The charge-generation and charge-tr~nsport layers can also contain other addenda such as level-ing agents, surfactants and plasticizers to enhance various physical properties. In addition, addenda to 5 modify the electrophotographic response of the ele-ment can be incorporated in the chsrge-transport layer. For example, contrast-control additives, such as certain hole-trapping agents and easily oxidized dyes, can be incorporated in the charge-transport layer. Such contrast-control additives are described in Research Disclosure, Vol. 122, June, 1974, p. 33, in an article entitled "additives For Contrast Con-trol In Organic Photoconductor Compositions and Ele-ments".
When the charge-generation layer or the charge-transport layer is solvent-coated, the compo-nents of the layer are dissolved or dispersed in a suitable liquid, together with the binder and other addenda. Useful liquids include aromatic hydrocar-20 bons such as benzene, toluene, xylene and mesltylene;
ketones such as acetone and butanone; halogenated hydrocarbons such as methylene chloride, chloroform and ethylene chloride; ethers including cyclic ethers ~uch as tetrahydrofuran; ethyl ether; and mixtures of the above.
A variety of electrically conducting sup-port~ can be employed in the elements of this inven-tion, such as paper (at a relative humidity above ~0 percent); aluminum-paper laminates; metal foils such 30 as sluminum foil, zinc foil, etc.; metal plates -Quch as aluminum, copper, zinc brass and galvanized plates; and vapor-deposited metal layers such as sil-ver, chromium, nickel and aluminum coated on paper or conventional photographic film baseR such as poly-(ethylene terephthalate), cellulose acetate, polysty-rene, etc. Conductive metals -quch as chromium or ~2~ 93 nickel can be vacuum-deposited on transparent film supports in sufficiently thin layers to allow the electrophotographic elements to be exposed from either side. An especially useful conducting support can be prepared by coating a poly(ethylene tereph-thalate) support with R conducting layer containing a semiconductor dispersed in a resin. Such conducting lsyers both with and without electrical barrier lay-ers are de~cribed in U.S. Patent 3,245,833 by Trevoy, issued April 12, 1966. Other useful conducting lay-er~ include compositions consisting essentially of an intimate mixture of at least one protective inorganic oxide and 30 to 70 percent by weight of at least one conducting metal, e.g., a vacuum-deposited cermet conducting layer as described by Rasch U.S. Patent 3,880,657 issued April 29, 1973. Likewise, a suita-ble conducting coating can be prepared from the sodium salt of a carboxyester lactone of maleic anhy-dride and a vinyl acetate polymer. Such conducting layer~ and methods for their preparstion are dis-closed in U.S. Patent Nos. 3,007,901 by Minsk issued November 7, 1961, and 3,262,807 by Sterman et al issued July 26, 1966.
The various layers of the element can be coated directly on the conducting subctrate~ It may be desirable, however, to use one or more intermedi-ate subbing layers to improve adhesion with the con-ducting substrate or to act as an electrical barrier layer between the overlying layer~ and the conducting substrate, as described in Dessauer U.S. Patent 2,940,348. Such subbing layers typically have a dry thicknes~ in the range of 0.01 to 5 ~m. Subbing materials include film-forming polymers such as cel-lulo~e nitrate, polyesters, copolymers of poly(vinyl pyrrolidone) and vinyl acetate, and various vinyli-dene chloride-containing polymers including two-, ~2~344~93 three- and four-component polymers prepared from a polymerizable blend of monomers or prepolymers con-taining at least 60 percent by weight of vinylidene chloride. Representative vinylidene chloride=
5 containing polymers include vinylidene chloride-methyl methacrylate-itaconic acid terpolymers as dis-closed in U.S. Patent 3,143,421. Various vinylidene chloride-containing hydrosol tetrapolymers which may be used include tetrapolymers of vlnylidene chloride, lO methyl acrylate, acrylonitrile and acrylic acid as di~closed in U.S. Patent 3,640,708. Other useful vinylidene chloride-containing copolymers include polytvinylidene chloride-methyl acrylate), poly-(vinylidene chloride-methacrylonitrile), poly(vinyli-15 dene chloride-acrylonitrile) and poly(vinylidene chloride-acrylonitrile-methyl acrylate). Other use-ful subbing materials include the so-called tergels described in Nadeau et al U. S. Patent 3,501,301 and the vinylldene chloride terpolymers descrlbed ln 20 Nadeau U.S. Patent 3,228,770.
One especlally useful subblng layer i~ a hydrophoblc film-forming polymer or copolymer free from any acid-containing group, such as a carboxyl group, prepared from a blend of monomers or prepoly-25 mers, each of said monomers or prepolymers containingone or more polymerizable ethylenically unsaturated groups. Such materials include many of the above=
mentioned copolymers and in addition, the following polymers; copolymers of polyvinyl pyrrolidone and 30 vinyl acetate, poly(vinylidene chloride methylmethac-rylate) and the like.
Optional overcoat layers can also be used.
For example, to improve surface hardness and resis-tance to abrasion, the surface layer of the element 35 can be coated with one or more electrically insulat-ing, organic polymer coatings or electrically in~u-8 ~ 9 3 lating, lnorganic coatings. A number of such coat-ings sre well-known in the art. Useful overcoats are described for example, in Research Disclosure, "Elec-trophotographic Elements, Materials and Processes:", 5 Vol. 109, p. 63, Paragraph V, May, 1973.
While it is expected that the photoconduc-tive elements of this invention will find principal use in the art of electrophotography, they can also be u-~ed in other art~, such as the solar-cell art, lO where photoconductive elements are employed.
The following examples further illustrate the invention.
SYnthesis ExamPle In a dry three-neck flask equipped with a lS stirrer and water condenser were placed 87 g (6.0 x 10 lM) diiminoisoindolinine, 57 g (1.6 x 10 lM) anhydrous indium tribromide and 700 ml of dry 1-methyl-2-pyrrolidinone. The mixture was heated to reflux under a nltrogen atmosphere with a heatin8 20 mantle. After reaching reflux ( 45 min), the mix-ture was maintained at reflux for 5 hr. The hot reaction mixture was filtered rapidly, to mlnimize cooling, through a preheated 2000-m1 medium-porosity ~intered glass funnel. A flow of nitrogen was main-tained over the funnel during the filtration anduntil the product cooled to room temperature. Trans-fer was completed with 50 ml of 1-methyl-2-pyrrolldi-none. The product was washed by slurrying twice in ethanol, twice in distilled water, and twice in ace-tone (350 ml 1~2 hr for each slurry). After dryingin a vacuum oven at 110~ C overnight, 33.8 g of a bluish purple crystalline product were obtained.
Purif~cation ExamPle The product of the above example wa~ puri-fied by treatment in 1-methyl-2-pyrrolidinone. In a three-neck flask equipped with a stirrer and water condenser were placed 31.8 g of the pigment of the synthesis example and 318 ml of 1-methyl-2-pyrrolidi-none. The mixture was heated to reflux under a nitrogen atmosphere and maintained at reflux for 2 hr. The hot reaction mixture was filtered as rapidly as possible to minimize coollng through a preheated coarse-porosity sintered glass funnel. A flow of nitrogen was maintained over the funnel during the flltration and until the product cooled to room tem-10 perature. Transfer was completed with 10 ml of 1-methyl-2-pyrrolidinone. The product was washed twice by slurrying in 250 ml of boiling distilled water (filtered hot). The product was rinsed on the funnel with acetone and extracted in a Soxhlet extractor overnight with acetone. The product was dried in a vacuum oven at 110 C overnight.
The yield of bromoindium phthalocyanine was 29.2 g (29% of theory).
20 Anal Calcd. for C32H16N81nBr: C, 54.3; H, 2.3;
N, 15.8; In, 16.2; Br, 11.
Found: C, 54.5; H, 1.8; N, 15.9; In, 16.0; Br, 11.
IR(KBr) (cm 1) 1610(w) 1480(g) 1410(m) 1335(s) 1290(s) 1170(w) 1120(s) 1090(sz) 1065(s) lOlO(w) 965(w) 895(s) 840(w) 810(w) 780(m) 760(m) 735(s).
The next example describes the preparation of a multiactive photoconductive element of the invention which contains a novel pigment as prepared in the examples above.
Photoconductive Element ExamPle A mixture of 0.45 g of poly(4,4'-~2-norbor-nylidene]diphenol carbonate), 8.0 g of bromoindium 35 phthalocyanine and 44.55 g of 1,1,2-trichloroethane was ball-milled for 3 days. Then 3.8 g of the poly-~2~ 3-17-carbonate, 251 g of dichloromethane, 0.5 g of 1,1,2-tri-chloroethane and 0.03 g of poly(dimethyl-co-methylphenyl siloxane) surfactant (DC510 surfactant a trademark of the Dow-Corning Company) were dissolved and mixed with the ball-milled mixture. The resulting dispersion was coated (0.075 g/ft dry coverage) (0.81 g/m ) and dried at 90C for 5 min on a nickelized film support to form a charge-generation layer.
Over this layer was coated a charge-transport layer comprlsing a polyester of 4,4'-(2-norbornylldene)diphenol with terephthalic acid and azelaic acid (40/60); 74.5 g of 1,1-bi~(4-di-~-tolyl-aminophenyl)cyclohexane; 74.5 g of tri-E-tolylamine;
and 12.0 g of bis(4-diethylamino)tetraphenylmethane;
2880 g of dichloromethane; 720 g of 1,1,2-trichloro-ethane; and 0.9 g of silicone surfactant was coated over the above charge-generation layer at 1.7 g/ft2 (18.3 g/m2) and dried at 90 C for 10 min. The ele-ment of thls example, when charged to -500 volts and 20 exposed with 830-nm monochromatic llght, dlscharged to -100 volts with an exposure of 10.5 erg~/cm2.
An X-ray diffractogrsm corre-~ponding to the above dispersed BrInPc charge-generation layer is shown in the drawing. The pigment is a C-centered 25 monoclinic form and exhibits ma~or peaXs at Bragg angles (2e) of 7.4, 16.7, 25.30, 27.5 and 28.4.
The following example illustrates the advan-tages of the method of the lnvention wherein 1-methyl-2-pyrrolidinone (NMP) is used as the reaction 30 solvent over syntheses using other solvents, even though the products of the latter are purl~ied by treatment with NMP.
ComParison ExamPle Five other syntheses of bromolndium phthalo-cyanine were carried out a~ described in the Synthe-sis Example ~bove, but uslng solvents other than .~
~284493 NMP. Each crude product, however, was treated with NMP as in the Purification Example. The five result-ing pigments were formulated into films for testing a~ photoconductors, as in the Photoconductive Element Example above. The films were then tested as photo-conductors as follows: each film was charged to -500 v (or as high as possible below that), exposed with 830-nm monochromatic radiation and discharged to -100 v. The energy required in ergs/cm2 was calculated.
lO The following table records the results of these tests, with reference to each synthesis solvent. The table also records the dark discharge rate for each film.
Energy Required at 830 nm Dark Discharge Solvent (erg~/cm2) Rate (v/sec) a-butyrolactone - 33.0 20 nitrobenzene 22 4.5 propylenecarbonate 14 15.0 a-chloron~phthalene 35 4.6 quinoline In these tests, the films containing the pigments synthesized in a-butyrolactone and quino-line could not be adequately charged. The first of these could be charged only to -420 v and the latter to much less than -420 v.
In contrast with the~e results, three photo-conductive films which were otherwise identical but contained bromoindium phthalocyanine pigment of the lnvention which was synthesized in NMP and also puri-fied in NMP gave the following results when tested in the qame way.
-` J3 2t3~3 E 830 nm Dark Decay Film ErRs/Cm2 v/sec B 13.3 2 C ll 1.5 Average 11.4 1.6 The~e results show the significant advan-tages obtained when the pigment is synthesized in NMP, as compared with pigments synthesized in other solvents, even though treated with NMP thereafter.
The invention has been described with refer-ence to certain preferred embodiments but it will be understood that variations and modifications can be made within the spirit and scope of the invention.
~ubstituted aminobenzaldehyde-(diphenylhydrazones) of U.S. P~tent 4,150,987 lssued April 24, 1979; alkylhy-drazones and arylhydrazones as described in U.S. Pat-ents 4,554,231, is~ued November 19, 1985; 4,487,824, issued December 11, 1984; 4,481,271, issued November 6, lg84; 4,456,671, i~sued June 26, 1984; 4,446,217, ~.28~d~93 _9_ issued May 1, 1984; and 4,423,129, issued December 27, 1983, which are illustrative of the p-type hydra-zones.
Other useful p-type charge transports ~re 5 the p-type photoconductors described in Research Dis-closure, Vol. 109, May, 1973, pages 61-67, paragraph IV (A) (2) through (13).
Representative of n-type charge transports are strong Lewis acids such as organic, including 10 metallo-organic, compounds containing one or more aromatic, including aromatically unsaturated hetero-cyclic, groups bearing an electron-withdrawing sub-stituent. These are useful because of their electron-accepting capability. Typical electron=
15 withdrawing substituents include cyano and nitro;
sulfonate; halogens such as chlorine, bromine and iodine; ketone groups; ester groups; acid anhydride groups; and other acid groups ~uch as carboxyl and quinone groups. Representative n-type aromatic 20 Lewis acids having electron-withdraw~ng substituents lnclude phthalic anhydride, tetrachlorophthalic anhy-dride, benzil, mellitlc anhydride, S-tricyanobenzene, picryl chloride, 2,4-dinitrochlorobenzene, 2,4-dini-trobromobenzene, 4-nitrobiphenyl, 4,4-dinitrobi-25 phenyl, 2,4,6-trinitroanisole, trichlorotrinitroben-zene, trinitro-o-toluene, 4,6-dichloro-1,3-dinitro-benzene, 4,6-dibromo-1,3-dinitrobenzene, ~-dinltro-benzene, chloranil, bromanil, 2,4,7-trinitro-9-fluo-renone, 2,4,5,7-tetranitrofluorenone, trinitroanthra-30 cene, dinitroacridine, tetracyanopyrene, dinitroan-thraquinone, and mixtures thereof.
Other u~eful n-type charge transports are conventional n-type organic photoconductors, for example, complexes of 2,4,6-trinitro-9-fluorenone and poly(vinyl carbazole). Still others are the n-type photoconductors described in Research Disclosure, ~8~93 Vol. 109, May, 1973, pages 61-67, paragraph IV(A) (2) through (13).
A single charge-transport layer or more than one can be employed. Where a slngle charge-transport layer is employed, it can be either a p-type or an n-type substance.
In one useful configuration, the charge=
generation layer is between the conducting support and a charge-transport layer or layers. This 10 arrangement provides flexibility and permits control of the physical and surface characteristics of the element by the nature of the charge-transport layer.
In another useful configuration, called the inverted multilayer configuration, the charge=
transport layer is between the conducting support and the charge-generation layer, the latter containing the phthalocyanine pigment of the present invention.
If the charge-generstion layer is to be exposed to actlnic radiation through the charge=
transport layer, it is preferred that the charge=
transport layer have little or no absorption in the region of the electromagnetic spectrum to which the charge-generation layer responds, thus permitting the maximum smount of actinic radiation to reach the 25 charge-generation layer. Where the charge-transport layer is not in the path of exposure, this does not apply.
Each of the charge-generation and charge=
transport layers is applied by solvent-coating the 30 active component in an electrically insulating film=
forming polymeric binder. The optimum ratio of charge-generation or charge-transport compound to binder can vary widely. In general, useful results are obtained when the amount of active chargez 35 generation or charge-transport compound within the 4~3 layer varies from about 5 to 90 weight percent based on the dry weight of the layer.
Binders in the charge-generation and charge=
transport layers are film-forming polymers having a fairly high dielectric strength and good electrically insulating properties. Examples include butadiene copolymers; polyvinyl toluene-styrene copolymers;
styrene-~lkyd resins; ~il$cone-alkyd resins; soya=
alkyd resins; vinylldene chloride-vinyl chloride 10 copolymers; poly(vinylidene chloride); vinylidene chloride-acrylonitrile copolymers; vinyl acetate=
vinyl chloride copolymers; poly(vinyl acetals) such as poly(vinyl butyral); nitrated polystyrene; poly-methylstyrene; i~obutylene polymers; polyesters such 15 a~ poly[ethylene-coalkylenebis(alkyleneoxyaryl)-phenylenedicarboxylate]; phenol formaldehyde resins;
ketone resins; polyamides; polycarbonates, polythio-carbonates; poly[ethylene-co-isopropylidene-2,2-bis-(ethyleneoxyphenylene)terephthalate]; copolymers of 20 vinyl haloacrylates and vinyl acetate such as poly-(vinyl-m-bromobenzoate-co-vinyl acetflte); chlorinated poly(olefins) such as chlorinated poly(ethylene), etc..
Polymers containing aromatic or heterocyclic 25 groups are most effective as binders because they provide little or no interference with the transport of charge carrier~ through the layer. Heterocyclic or aromatic containing polymers which are especially useful in p-type charge-transport layers include 30 styrene-containing polymers, bisphenol A polycarbon-ate polymers, phenol formaldehyde resins, polyesters such as poly[ethylene-co-isopropylidene2,2-bis-(eth-yleneoxy-phenylene)]terephthalate, and copolymers of vinyl haloacrylates and vinyl acetate such aq poly-(vinyl-m-bromobenzoate-co-vinyl acetate).
~8~g3 The charge-generation and charge-tr~nsport layers can also contain other addenda such as level-ing agents, surfactants and plasticizers to enhance various physical properties. In addition, addenda to 5 modify the electrophotographic response of the ele-ment can be incorporated in the chsrge-transport layer. For example, contrast-control additives, such as certain hole-trapping agents and easily oxidized dyes, can be incorporated in the charge-transport layer. Such contrast-control additives are described in Research Disclosure, Vol. 122, June, 1974, p. 33, in an article entitled "additives For Contrast Con-trol In Organic Photoconductor Compositions and Ele-ments".
When the charge-generation layer or the charge-transport layer is solvent-coated, the compo-nents of the layer are dissolved or dispersed in a suitable liquid, together with the binder and other addenda. Useful liquids include aromatic hydrocar-20 bons such as benzene, toluene, xylene and mesltylene;
ketones such as acetone and butanone; halogenated hydrocarbons such as methylene chloride, chloroform and ethylene chloride; ethers including cyclic ethers ~uch as tetrahydrofuran; ethyl ether; and mixtures of the above.
A variety of electrically conducting sup-port~ can be employed in the elements of this inven-tion, such as paper (at a relative humidity above ~0 percent); aluminum-paper laminates; metal foils such 30 as sluminum foil, zinc foil, etc.; metal plates -Quch as aluminum, copper, zinc brass and galvanized plates; and vapor-deposited metal layers such as sil-ver, chromium, nickel and aluminum coated on paper or conventional photographic film baseR such as poly-(ethylene terephthalate), cellulose acetate, polysty-rene, etc. Conductive metals -quch as chromium or ~2~ 93 nickel can be vacuum-deposited on transparent film supports in sufficiently thin layers to allow the electrophotographic elements to be exposed from either side. An especially useful conducting support can be prepared by coating a poly(ethylene tereph-thalate) support with R conducting layer containing a semiconductor dispersed in a resin. Such conducting lsyers both with and without electrical barrier lay-ers are de~cribed in U.S. Patent 3,245,833 by Trevoy, issued April 12, 1966. Other useful conducting lay-er~ include compositions consisting essentially of an intimate mixture of at least one protective inorganic oxide and 30 to 70 percent by weight of at least one conducting metal, e.g., a vacuum-deposited cermet conducting layer as described by Rasch U.S. Patent 3,880,657 issued April 29, 1973. Likewise, a suita-ble conducting coating can be prepared from the sodium salt of a carboxyester lactone of maleic anhy-dride and a vinyl acetate polymer. Such conducting layer~ and methods for their preparstion are dis-closed in U.S. Patent Nos. 3,007,901 by Minsk issued November 7, 1961, and 3,262,807 by Sterman et al issued July 26, 1966.
The various layers of the element can be coated directly on the conducting subctrate~ It may be desirable, however, to use one or more intermedi-ate subbing layers to improve adhesion with the con-ducting substrate or to act as an electrical barrier layer between the overlying layer~ and the conducting substrate, as described in Dessauer U.S. Patent 2,940,348. Such subbing layers typically have a dry thicknes~ in the range of 0.01 to 5 ~m. Subbing materials include film-forming polymers such as cel-lulo~e nitrate, polyesters, copolymers of poly(vinyl pyrrolidone) and vinyl acetate, and various vinyli-dene chloride-containing polymers including two-, ~2~344~93 three- and four-component polymers prepared from a polymerizable blend of monomers or prepolymers con-taining at least 60 percent by weight of vinylidene chloride. Representative vinylidene chloride=
5 containing polymers include vinylidene chloride-methyl methacrylate-itaconic acid terpolymers as dis-closed in U.S. Patent 3,143,421. Various vinylidene chloride-containing hydrosol tetrapolymers which may be used include tetrapolymers of vlnylidene chloride, lO methyl acrylate, acrylonitrile and acrylic acid as di~closed in U.S. Patent 3,640,708. Other useful vinylidene chloride-containing copolymers include polytvinylidene chloride-methyl acrylate), poly-(vinylidene chloride-methacrylonitrile), poly(vinyli-15 dene chloride-acrylonitrile) and poly(vinylidene chloride-acrylonitrile-methyl acrylate). Other use-ful subbing materials include the so-called tergels described in Nadeau et al U. S. Patent 3,501,301 and the vinylldene chloride terpolymers descrlbed ln 20 Nadeau U.S. Patent 3,228,770.
One especlally useful subblng layer i~ a hydrophoblc film-forming polymer or copolymer free from any acid-containing group, such as a carboxyl group, prepared from a blend of monomers or prepoly-25 mers, each of said monomers or prepolymers containingone or more polymerizable ethylenically unsaturated groups. Such materials include many of the above=
mentioned copolymers and in addition, the following polymers; copolymers of polyvinyl pyrrolidone and 30 vinyl acetate, poly(vinylidene chloride methylmethac-rylate) and the like.
Optional overcoat layers can also be used.
For example, to improve surface hardness and resis-tance to abrasion, the surface layer of the element 35 can be coated with one or more electrically insulat-ing, organic polymer coatings or electrically in~u-8 ~ 9 3 lating, lnorganic coatings. A number of such coat-ings sre well-known in the art. Useful overcoats are described for example, in Research Disclosure, "Elec-trophotographic Elements, Materials and Processes:", 5 Vol. 109, p. 63, Paragraph V, May, 1973.
While it is expected that the photoconduc-tive elements of this invention will find principal use in the art of electrophotography, they can also be u-~ed in other art~, such as the solar-cell art, lO where photoconductive elements are employed.
The following examples further illustrate the invention.
SYnthesis ExamPle In a dry three-neck flask equipped with a lS stirrer and water condenser were placed 87 g (6.0 x 10 lM) diiminoisoindolinine, 57 g (1.6 x 10 lM) anhydrous indium tribromide and 700 ml of dry 1-methyl-2-pyrrolidinone. The mixture was heated to reflux under a nltrogen atmosphere with a heatin8 20 mantle. After reaching reflux ( 45 min), the mix-ture was maintained at reflux for 5 hr. The hot reaction mixture was filtered rapidly, to mlnimize cooling, through a preheated 2000-m1 medium-porosity ~intered glass funnel. A flow of nitrogen was main-tained over the funnel during the filtration anduntil the product cooled to room temperature. Trans-fer was completed with 50 ml of 1-methyl-2-pyrrolldi-none. The product was washed by slurrying twice in ethanol, twice in distilled water, and twice in ace-tone (350 ml 1~2 hr for each slurry). After dryingin a vacuum oven at 110~ C overnight, 33.8 g of a bluish purple crystalline product were obtained.
Purif~cation ExamPle The product of the above example wa~ puri-fied by treatment in 1-methyl-2-pyrrolidinone. In a three-neck flask equipped with a stirrer and water condenser were placed 31.8 g of the pigment of the synthesis example and 318 ml of 1-methyl-2-pyrrolidi-none. The mixture was heated to reflux under a nitrogen atmosphere and maintained at reflux for 2 hr. The hot reaction mixture was filtered as rapidly as possible to minimize coollng through a preheated coarse-porosity sintered glass funnel. A flow of nitrogen was maintained over the funnel during the flltration and until the product cooled to room tem-10 perature. Transfer was completed with 10 ml of 1-methyl-2-pyrrolidinone. The product was washed twice by slurrying in 250 ml of boiling distilled water (filtered hot). The product was rinsed on the funnel with acetone and extracted in a Soxhlet extractor overnight with acetone. The product was dried in a vacuum oven at 110 C overnight.
The yield of bromoindium phthalocyanine was 29.2 g (29% of theory).
20 Anal Calcd. for C32H16N81nBr: C, 54.3; H, 2.3;
N, 15.8; In, 16.2; Br, 11.
Found: C, 54.5; H, 1.8; N, 15.9; In, 16.0; Br, 11.
IR(KBr) (cm 1) 1610(w) 1480(g) 1410(m) 1335(s) 1290(s) 1170(w) 1120(s) 1090(sz) 1065(s) lOlO(w) 965(w) 895(s) 840(w) 810(w) 780(m) 760(m) 735(s).
The next example describes the preparation of a multiactive photoconductive element of the invention which contains a novel pigment as prepared in the examples above.
Photoconductive Element ExamPle A mixture of 0.45 g of poly(4,4'-~2-norbor-nylidene]diphenol carbonate), 8.0 g of bromoindium 35 phthalocyanine and 44.55 g of 1,1,2-trichloroethane was ball-milled for 3 days. Then 3.8 g of the poly-~2~ 3-17-carbonate, 251 g of dichloromethane, 0.5 g of 1,1,2-tri-chloroethane and 0.03 g of poly(dimethyl-co-methylphenyl siloxane) surfactant (DC510 surfactant a trademark of the Dow-Corning Company) were dissolved and mixed with the ball-milled mixture. The resulting dispersion was coated (0.075 g/ft dry coverage) (0.81 g/m ) and dried at 90C for 5 min on a nickelized film support to form a charge-generation layer.
Over this layer was coated a charge-transport layer comprlsing a polyester of 4,4'-(2-norbornylldene)diphenol with terephthalic acid and azelaic acid (40/60); 74.5 g of 1,1-bi~(4-di-~-tolyl-aminophenyl)cyclohexane; 74.5 g of tri-E-tolylamine;
and 12.0 g of bis(4-diethylamino)tetraphenylmethane;
2880 g of dichloromethane; 720 g of 1,1,2-trichloro-ethane; and 0.9 g of silicone surfactant was coated over the above charge-generation layer at 1.7 g/ft2 (18.3 g/m2) and dried at 90 C for 10 min. The ele-ment of thls example, when charged to -500 volts and 20 exposed with 830-nm monochromatic llght, dlscharged to -100 volts with an exposure of 10.5 erg~/cm2.
An X-ray diffractogrsm corre-~ponding to the above dispersed BrInPc charge-generation layer is shown in the drawing. The pigment is a C-centered 25 monoclinic form and exhibits ma~or peaXs at Bragg angles (2e) of 7.4, 16.7, 25.30, 27.5 and 28.4.
The following example illustrates the advan-tages of the method of the lnvention wherein 1-methyl-2-pyrrolidinone (NMP) is used as the reaction 30 solvent over syntheses using other solvents, even though the products of the latter are purl~ied by treatment with NMP.
ComParison ExamPle Five other syntheses of bromolndium phthalo-cyanine were carried out a~ described in the Synthe-sis Example ~bove, but uslng solvents other than .~
~284493 NMP. Each crude product, however, was treated with NMP as in the Purification Example. The five result-ing pigments were formulated into films for testing a~ photoconductors, as in the Photoconductive Element Example above. The films were then tested as photo-conductors as follows: each film was charged to -500 v (or as high as possible below that), exposed with 830-nm monochromatic radiation and discharged to -100 v. The energy required in ergs/cm2 was calculated.
lO The following table records the results of these tests, with reference to each synthesis solvent. The table also records the dark discharge rate for each film.
Energy Required at 830 nm Dark Discharge Solvent (erg~/cm2) Rate (v/sec) a-butyrolactone - 33.0 20 nitrobenzene 22 4.5 propylenecarbonate 14 15.0 a-chloron~phthalene 35 4.6 quinoline In these tests, the films containing the pigments synthesized in a-butyrolactone and quino-line could not be adequately charged. The first of these could be charged only to -420 v and the latter to much less than -420 v.
In contrast with the~e results, three photo-conductive films which were otherwise identical but contained bromoindium phthalocyanine pigment of the lnvention which was synthesized in NMP and also puri-fied in NMP gave the following results when tested in the qame way.
-` J3 2t3~3 E 830 nm Dark Decay Film ErRs/Cm2 v/sec B 13.3 2 C ll 1.5 Average 11.4 1.6 The~e results show the significant advan-tages obtained when the pigment is synthesized in NMP, as compared with pigments synthesized in other solvents, even though treated with NMP thereafter.
The invention has been described with refer-ence to certain preferred embodiments but it will be understood that variations and modifications can be made within the spirit and scope of the invention.
Claims (11)
1. A method of preparing a bromoindium phthalocyanine pigment which comprises reacting diiminoisoindoline having a purity of at least 99 percent by weight, with indium bromide in a solvent comprising 1-methyl-2-pyrrolidinone.
2. A method according to Claim 1 wherein the indium bromide is indium tribromide.
3. A method according to Claim 1 wherein the diiminoisoindoline is prepared by passing a stream of gaseous ammonia through a solution of phthalonitrile, methanol and sodium methoxide, the phthalonitrile having a purity of at least 99 weight percent.
4. A method according to Claim 1 wherein the reaction product is purified by treatment with 1-methyl-2-pyrrolidinone.
5. A multiactive photoconductive element comprising an electrically conductive support, a charge-generation layer and a charge-transport layer, wherein the charge-generation layer comprises dispersion-coated bromoindium phthalocyanine prepared by the reaction of diiminoisoindoline having a purity of at least 99 percent by weight, with indium bromide in the presence of 1-methyl-2-pyrrolidinone as the reaction solvent.
6. An element according to Claim 5 wherein the indium bromide is indium tribromide.
7. A C-centered monoclinic bromoindium phthalocyanine pigment having X-ray diffractogram major peaks at Bragg angles (2.THETA.) of 7.4°, 16.7°, 25.3°, 27.5° and 28.4°
8. A photoconductive element comprising an electrically conductive support and a photoconductive layer which contains bromoindium phthalocyanine pig-ment according to Claim 7.
9. A multiactive photoconductive element comprising an electrically conductive support, a charge-transport layer and a charge-generation layer which contains a bromoindium phthalocyanine pigment according to Claim 7.
10. A multiactive photoconductive element according to Claim 9 wherein the bromoindium phthalo-cyanine pigment is dispersion-coated.
11. A photoconductive element comprising an electrically conductive support and a photoconductive layer prepared by the process of Claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US886,142 | 1986-07-16 | ||
| US06/886,142 US4666802A (en) | 1986-07-16 | 1986-07-16 | Photoconductive elements sensitive to infrared radiation having a bromoindium phthalocyanine pigment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1284493C true CA1284493C (en) | 1991-05-28 |
Family
ID=25388467
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000536714A Expired - Fee Related CA1284493C (en) | 1986-07-16 | 1987-05-08 | Pigments and photoconductive elements sensitive to infrared radiation |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4666802A (en) |
| EP (1) | EP0253169A3 (en) |
| JP (1) | JPS6327562A (en) |
| CA (1) | CA1284493C (en) |
Families Citing this family (40)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4727139A (en) * | 1986-07-16 | 1988-02-23 | Eastman Kodak Company | Pigments and photoconductive elements sensitive to infrared radiation |
| US4840861A (en) * | 1988-03-16 | 1989-06-20 | Eastman Kodak Company | Multiactive electrophotographic element |
| US4913996A (en) * | 1988-12-21 | 1990-04-03 | Eastman Kodak Company | Electrophotographic elements containing certain anthraquinone derivatives as electron-transport agents |
| US4869985A (en) * | 1988-12-21 | 1989-09-26 | Eastman Kodak Company | Electrophotographic elements containing certain naphthoquinone derivatives as electron-transport agents |
| US4921637A (en) * | 1988-12-21 | 1990-05-01 | Eastman Kodak Company | Naphthoquinone derivatives |
| US4909966A (en) * | 1988-12-21 | 1990-03-20 | Eastman Kodak Company | Naphthoquinone derivatives |
| US4869984A (en) * | 1988-12-21 | 1989-09-26 | Eastman Kodak Company | Electrophotographic elements containing certain naphthoquinone derivatives as electron-transport agents |
| US5288573A (en) * | 1991-04-10 | 1994-02-22 | Eastman Kodak Company | Photoconductive elements which are sensitive to near-infrared radiation |
| US5213927A (en) * | 1990-12-17 | 1993-05-25 | Eastman Kodak Company | Inverse multiactive electrophotographic element |
| CA2058227C (en) * | 1990-12-26 | 2001-03-06 | Takahisa Oguchi | Method of preparing alkoxyphthalocyanine |
| US5112935A (en) * | 1991-08-22 | 1992-05-12 | Eastman Kodak Company | Polyester useful in multiactive electrophotographic element |
| US5190840A (en) * | 1991-08-22 | 1993-03-02 | Eastman Kodak Company | Multiactive electrophotographic element comprising a polyester of a tetramethyl bisphenol A derivative |
| USH1607H (en) * | 1991-08-22 | 1996-11-05 | Eastman Kodak Company | Multiactive electrophotographic element |
| US5135828A (en) * | 1991-08-22 | 1992-08-04 | Eastman Kodak Company | Multiactive electrophotographic element |
| US5238766A (en) * | 1992-02-13 | 1993-08-24 | Eastman Kodak Company | Coating compositions containing a titanyl fluorophthalocyanine pigment |
| US5238764A (en) * | 1992-02-13 | 1993-08-24 | Eastman Kodak Company | Electrophotographic elements containing a titanyl fluorophthalocyanine pigment |
| US5272032A (en) * | 1993-01-04 | 1993-12-21 | Eastman Kodak Company | Multiactive electrophotographic elements containing electron transport agents |
| US5500317A (en) * | 1994-06-16 | 1996-03-19 | Eastman Kodak Company | Electrophotographic elements containing soluble cyclic sulfone electron transport agents |
| US5523189A (en) * | 1994-10-27 | 1996-06-04 | Eastman Kodak Company | Electrophotographic recording elements and preparation method |
| US5629418A (en) * | 1994-10-27 | 1997-05-13 | Eastman Kodak Company | Preparation of titanyl fluorophthalocyanines |
| US5468583A (en) * | 1994-12-28 | 1995-11-21 | Eastman Kodak Company | Cyclic bis-dicarboximide electron transport compounds for electrophotography |
| US5773181A (en) * | 1995-05-23 | 1998-06-30 | Eastman Kodak Company | Non-uniformly substituted phthalocyanine compositions preparation methods, and electrophotographic elements |
| US5900342A (en) * | 1996-04-26 | 1999-05-04 | Eastman Kodak Company | Photoconductive element having an outermost layer of a fluorinated diamond-like carbon and method of making the same |
| US5886359A (en) * | 1996-06-13 | 1999-03-23 | Eastman Kodak Company | X-ray dectector, detection assembly, and method |
| US6368664B1 (en) | 1999-05-03 | 2002-04-09 | Guardian Industries Corp. | Method of ion beam milling substrate prior to depositing diamond like carbon layer thereon |
| US6335086B1 (en) | 1999-05-03 | 2002-01-01 | Guardian Industries Corporation | Hydrophobic coating including DLC on substrate |
| US6284377B1 (en) | 1999-05-03 | 2001-09-04 | Guardian Industries Corporation | Hydrophobic coating including DLC on substrate |
| US6338901B1 (en) | 1999-05-03 | 2002-01-15 | Guardian Industries Corporation | Hydrophobic coating including DLC on substrate |
| US6491987B2 (en) | 1999-05-03 | 2002-12-10 | Guardian Indusries Corp. | Process for depositing DLC inclusive coating with surface roughness on substrate |
| US6461731B1 (en) | 1999-05-03 | 2002-10-08 | Guardian Industries Corp. | Solar management coating system including protective DLC |
| US6312808B1 (en) | 1999-05-03 | 2001-11-06 | Guardian Industries Corporation | Hydrophobic coating with DLC & FAS on substrate |
| US6277480B1 (en) | 1999-05-03 | 2001-08-21 | Guardian Industries Corporation | Coated article including a DLC inclusive layer(s) and a layer(s) deposited using siloxane gas, and corresponding method |
| US6280834B1 (en) | 1999-05-03 | 2001-08-28 | Guardian Industries Corporation | Hydrophobic coating including DLC and/or FAS on substrate |
| US6475573B1 (en) | 1999-05-03 | 2002-11-05 | Guardian Industries Corp. | Method of depositing DLC inclusive coating on substrate |
| US6447891B1 (en) | 1999-05-03 | 2002-09-10 | Guardian Industries Corp. | Low-E coating system including protective DLC |
| US7449268B2 (en) * | 2005-05-27 | 2008-11-11 | Xerox Corporation | Polymers of napthalene tetracarboxylic diimide dimers |
| US7390601B2 (en) * | 2005-06-16 | 2008-06-24 | Xerox Corporation | Imaging member comprising modified binder |
| US7923184B2 (en) * | 2007-09-27 | 2011-04-12 | Eastman Kodak Company | Photoconductors containing trimellitimide esters |
| US7892713B2 (en) * | 2007-09-27 | 2011-02-22 | Eastman Kodak Company | Photoconductors containing terephthalate esters |
| US7732116B2 (en) * | 2007-09-27 | 2010-06-08 | Eastman Kodak Company | Photoconductors containing N-arylphthalimides |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2772285A (en) * | 1953-01-21 | 1956-11-27 | Du Pont | Process for producing copper-phthalocyanine precursor |
| US3615558A (en) * | 1964-07-23 | 1971-10-26 | Xerox Corp | Photoelectrophoretic imaging process employing a finely divided phthalocyanine pigment |
| US3479126A (en) * | 1966-05-02 | 1969-11-18 | Bayer Ag | Phthalocyanine type dyestuffs |
| US3759947A (en) * | 1967-04-07 | 1973-09-18 | Ciba Geigy Ag | Tert-silyl and tert-alkyl phthalocyanine dyestuffs |
| GB1156738A (en) * | 1967-07-15 | 1969-07-02 | Bayer Ag | Printing and Dyeing Processes |
| US3672979A (en) * | 1970-01-02 | 1972-06-27 | Xerox Corp | Method of producing a phthalocyanine photoconductive layer |
| US3708292A (en) * | 1971-05-21 | 1973-01-02 | Xerox Corp | Pi-form metal phthalocyanine |
| DE2250938A1 (en) * | 1972-10-18 | 1974-05-02 | Basf Ag | Finely divided metal phthalocyanines - prepd. from 1,3-diimino-isoindolines in presence of benzonitriles or aliphatic nitriles |
| JPS5284231A (en) * | 1976-01-01 | 1977-07-13 | Nippon Shokubai Kagaku Kogyo Co Ltd | Rho type copper phthalocyanine |
| US4382033A (en) * | 1980-10-06 | 1983-05-03 | Eastman Kodak Company | Novel phthalocyanine pigments |
| JPS57148745A (en) * | 1981-03-11 | 1982-09-14 | Nippon Telegr & Teleph Corp <Ntt> | Lamination type electrophotographic receptor |
| US4471039A (en) * | 1982-11-22 | 1984-09-11 | Eastman Kodak Company | Photoconductive elements sensitive to radiation in the infrared region of the spectrum |
| DE3411070C2 (en) * | 1983-03-25 | 1986-10-30 | Oki Electric Industry Co., Ltd., Tokio/Tokyo | Electrophotographic recording material |
-
1986
- 1986-07-16 US US06/886,142 patent/US4666802A/en not_active Expired - Fee Related
-
1987
- 1987-05-08 CA CA000536714A patent/CA1284493C/en not_active Expired - Fee Related
- 1987-06-25 EP EP87109132A patent/EP0253169A3/en not_active Withdrawn
- 1987-07-13 JP JP62174573A patent/JPS6327562A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6327562A (en) | 1988-02-05 |
| EP0253169A3 (en) | 1990-03-21 |
| EP0253169A2 (en) | 1988-01-20 |
| US4666802A (en) | 1987-05-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1284493C (en) | Pigments and photoconductive elements sensitive to infrared radiation | |
| EP0244780B1 (en) | Photoconductive phthalocyanine pigments, electrophotographic elements containing them, and a method of use | |
| US4719163A (en) | Multi-active photoconductive insulating elements exhibiting far red sensitivity | |
| US4578334A (en) | Multi-active photoconductive insulating elements and method for their manufacture | |
| US4471039A (en) | Photoconductive elements sensitive to radiation in the infrared region of the spectrum | |
| US5128226A (en) | Electrophotographic element containing barrier layer | |
| US4092162A (en) | Nitrogen containing polymers aelements | |
| EP0534514B1 (en) | Electrophotographic recording material | |
| EP0795791A1 (en) | Electrophotographic photoreceptor | |
| EP0443566A1 (en) | Method for preparing coating compositions containing photoconductive perylene pigments | |
| EP0447826A1 (en) | Electrophotographic recording elements containing photoconductive perylene pigments | |
| JPS60207148A (en) | Photoconductive device containing perylene dye composition | |
| US4106934A (en) | Photoconductive compositions and elements with charge transfer complexes | |
| US4971873A (en) | Solvent soluble polyimides as binders in photoconductor elements | |
| GB1599166A (en) | Photoconductive element | |
| US4746741A (en) | N,N'-bis[2-(3-methylphenyl)ethyl]-perylene-3,4:9,10-bis (dicarboximide) compound use thereof in multi-active photoconductive insulating elements exhibiting far red sensitivity | |
| US5952140A (en) | Bipolar charge transport materials useful in electrophotography | |
| US4727139A (en) | Pigments and photoconductive elements sensitive to infrared radiation | |
| JPH04348350A (en) | Electrophotographic sensitive body | |
| JPH04184449A (en) | Coating liquid | |
| US4618560A (en) | Multi-active photoconductive insulating elements exhibiting very high electrophotographic speed and panchromatic sensitivity and method for their manufacture | |
| JPH04184452A (en) | Coating liquid | |
| JPH04361269A (en) | Electrophotographic sensitive material | |
| US6214504B1 (en) | Photoconductive imaging members | |
| JPH04184448A (en) | Coating liquid |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |