US 3896184 A
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United States Patent [191 Bergfjord et a1.
[ POLYMERS OF BENZANTHRACENE AS ACTIVE MATRIX MATERIALS [751 Inventors: John Alf Bergfjord, Macedon;
Richard William Radler, Marion; Richard Phillip Millonzi, Macedon. all of N.Y.
 Assignee: Xerox Corporation, Stamford,
22 Filed: June 27,1973
21 Appl. No.: 374,163
 U.S. C1. 260/669 QZ; 96/1.5; 252/623 0; 260/599; 260/651 HA; 260/668 F  Int. Cl. C07c 15/20 158] Field of Search... 260/668 F, 669 O2, 651 HA, 260/599  References Cited UNITED STATES PATENTS 2,496,867 2/1950 Flowers 260/669 QZ 3,041,166 6/1962 Bardeen 96/].5 3.121.006 2/1964 Middleton ct a1. 96/].5 3,121,007 2/1964 Middleton et al. 96/].5
OTHER PUBLICATIONS Foerst, Newer Methods of Preparative Organic Chem.
[ July 22, 1975 Academic Press, New York (1964), pp. 111, 112, ll8l2O 84129.
Tanikawa et al., Bull. of the Chem. Soc. of Japan; Vol. 41 Pp. 2719-2722 (1968).
Chem. Abs.; 59, 771d (1963).
Chem. Abs; 61, 5777d (1964).
Primary Examiner-C. Davis Attorney, Agent, or Firm-John E. Crowe; James J. Ralabate; James P. OSullivan  ABSTRACT Vinyl polycyclic aromatics, particularly polycyclics having three or more nuclei and their polymers utilizable as active matrix material for xerographic purposes are obtained in high yield by initial conversion of the polycyclic reactant to the aldehyde in the presence of a haloalkyl ether as a formulating agent in the presence of a Friedl-Crafts type catalyst. The aldehyde intermediate is then coverted to the vinyl monomer by using a Wittig-type reaction and, thereafter. polymerized, as desired, by the use of a cationic mechanism.
10 Claims, No Drawings POLYMERS OF BENZANTHRACENE AS ACTIVE MATRIX MATERIALS This invention relates to a high yield process for obtaining vinyl monomers of polycyclic aromatics such as substituted 1,2-benzanthracene, corresponding polymeric materials and their utilization an unique active matrix materials for xerographic purposes.
BACKGROUND OF THE INVENTION The formation and development of images on photoconductive materials by electrostatic means is well known. The best known of the commercial processes utilizes a latent electrostatic image on an imaging surface by first uniformly electrostatically charging the surface in the dark and then exposing the electrostatically charged surface to a light and shadow image. The light-struck areas of the imaging layer are thus made conductive and the electrostatic charge selectively dissipated in these areas. The latent positive electrostatic image remaining is made visible by development with a finely divided colored electroscopic material known as toner". This material is preferentially attracted to those areas on the image-bearing surface which have retained an electrostatic charge. After development, the image is permanently affixed to the photoconductor or transferred to some other suitable material such as paper.
Photoconductor layers useful for xerographic purposes 1 may be homogeneous layers of a single material such as vitreous selenium or (2) may be composite layers containing a photoconductor and another material. One type of composite layer used in xerography is illustrated by US. Pat. No. 3,121,006 to Middleton and Reynolds, which describes a number of binder layers containing finely-divided particles of a photoconductive inorganic compound such as zinc oxide, dispersed in an electrically insulating organic resin binder. In the systems described in Middleton et al., the binder comprises a material which is incapable of transporting the injected charge carriers generated by the photoconductor particles for any significant distance. As a result, the photoconductor particles must be in substantially continuous particle-to-particle contact throughout the layer to permit sufficient charge dissipation in the lightstruck areas. The uniform dispersion of photoconductor particles describes in Middleton et 21]., therefore, represents a high volume concentration (i.e. up to about 50 percent or more by volume) of photoconductive particles.
It has also been found, however, that high photoconductor loadings in a binder layer can adversely affect physical continuity and significantly reduce the mechanical properties of a binder layer. High photoconductor loadings, therefore, are often characterized by brittleness and lack of durability. On the other hand, when the photoconductor concentration is substantially reduced below about 50 percent by volume, the surface discharge rate is correspondingly reduced, making high speed cyclic or repeated imaging difficult or impossible.
In the second Middleton et 211. patent (US. Pat. No. 3,121,007) another type of photoconductor is considercd, which includes a two phase photoconductive binder layer comprising photoconductive insulating matrix. The photoconductor is in the form a particulate photoconductive inorganic crystalline pigment broadly disclosed as being present in an amount from about 5 to percent by weight. Here photo discharge is probably effected by a combination of charge carriers generated in the photoconductive insulating matrix material and charge carriers injected directly from the photoconductive crystalline pigment into the photoconductive insulating matrix.
U.S. Pat. No. 3,037,861 to Hoegl et al. indicates that polyvinyl carbazole exhibits some long-wave U. V. sensitivity and suggests that spectral sensitivity can be extended into the visible light spectrum by the addition of dye sensitizers. This patent further suggests that other additives such as zinc oxides or titanium dioxide can be used in conjunction with polyvinyl carbazole as a photoconductor (with or without additive materials) to extend spectral sensitivity.
In addition to the above, certain specialized layered structures have been proposed for reflex imaging. In US. Pat. No. 3,165,405 to Hoesterey, for instance, there is a two layered zinc oxide binder structure. Hoesterey requires two separate contiguous photoconductive layers having different spectral sensitivities in order to carry out a particular reflex imaging sequence. This device utilizes the properties of multiple photoconductive layers in order to obtain the combined advantages of the separate photoresponse of the respec tive photoconductive layers.
Although the above patents rely upon distinct mechanisms of discharge throughout the photoconductive layer, they suffer from a common deficiency insofar as the photoconductive surface is very susceptible to abrasion, chemical attack, heat, and multiple exposures to light during cycling. As a result it is common to experience a gradual deterioration in the electrical characteristics of the photoconductive layer. This is manifest, for instance, in printing of surface defects and scratches, and in the existence of localized areas of persistent conductivity.
Another form of composite photosensitive layer which has also been considered by the prior art includes a layer of photoconductive material which is covered with a relatively thick plastic layer and coated on a supporting substrate.
US. Pat. No. 3,041,166 to Bardeen describes such a configuration in which a transparent plastic material overlays a layer of vitreous selenium'contained on a supporting substrate. The plastic material is described as one having a long range for charge carriers of the desired polarity. In operation, the free surface of the transparent plastic is electrostatically charged to a given polarity. The device is then exposed to activating radiation which generates a hole-electron pair in the photoconductive layer. The electron moves through the plastic layer and neutralizes a positive charge on the free surface of the plastic layer thereby creating an electrostatic image. Bardeen, however, does not teach any specific plastic materials which will function in this manner, and confines his examples to structures which use a photoconductor material for the top layer.
While the later patent represents a significant breakthrough, it has been found that it is very difficult, if not impossible to obtain and effectively utilize certain types of potentially suitable compounds as charge transmitting materials. This is true of various polycyclic aromatic subgroups, and particularly polycyclic aromatics, such as 1,2-benzanthracene and its derivatives which exhibit substantial 1r electron delocalization.
It is an object of the present invention to synthesize and utilize active polycyclic aromatic matrix components, particular vinyl polycyclic aromatic derivatives, suitable for transporting photoconductor-generated holes or electrons for general electrophotographic and xerographic purposes.
lt is a further object to obtain new polymeric derivatives for use as active matrix components for xerographic purposes.
THE INVENTION The above objects are realized by synthesizing and utilizing as active matrix material, inclusive of overcoating, an essentially colorless polycyclic compound having at least four and preferably 4-6 cyclic nuclei, particularly, vinyl substituted polycyclics derived from a polycyclic aromatic reactant.
Such material is obtained in excellent yield by contacting a corresponding polycyclic reactant represented by the formula with at least a molar amount of a haloalkyl ether of the formula R (Ii) CH-OA a lower alkyl (Ex. a S-methyl-1,2-benzanthracene), a lower alkoxy or a phenyl substituted 1,2- benzanthracene;
A in the above formulating agent is individually defined as an alkyl group such as an alkyl group of 1-8 carbon atoms and preferably a lower alkyl group of 1-8 carbon atoms such as methyl, isopropyl, or octyl;
For purposes of the present invention the molar ratio of formylating agent (Formula lI)-to-polycyclic reactant (formula I) can vary from about 1.0-1.5 to l; a satisfactory catalytic amount of SnCl and/or TiCl for instance, is found to be in equimolar amount with respect to the haloalkyl ether formylating agent. This reaction step is usefully carried out, for instance, in methylene chloride at a temperature within the range of about -i 5 to 40C, and preferably at about 0 -25C, to obtain a decomposible intermediate product which. in turn, forms a polycyclic aldehyde intermediate represented by the formula 0 I (III) Q bn wherein Y is conveniently defined as a phenyl or an alkyl group inclusive of phenyl, methyl and octadecyl, the reaction proceeding at about 20 C to obtain the corresponding vinyl-substituted polycyclic monomeric product represented by the formula (V) Q CH=CH The vinyl monomeric product is converted, as desired, into the corresponding polymer by the use of a cationic mechanism. Such a polymeric reaction is conveniently effected by contacting the vinyl monomer in a reaction solvent with an initiating amount of a Lewis Acid such as Boron Trifluoride. This reaction is preferably effected in an inert atmosphere and in an essentially moisture-free environment. For this purpose the reaction solvent can be a chlorinated hydrocarbon such as methylene chloride or tetrahydrofurane. For most efficient polymerization, the temperature of the reaction mixture usefully varies from about 50 to 75C, depending upon the solvent used, and about -500 ppm of initiator is found sufficient to effect the reaction. The product is then conveniently recovered by precipitation with methanol and purified in the usual manner. a
When a copolymer is desired, a controlled admixture of reactants containing up to 10% by weight of a second monomer such as a vinyl ether (ex. isobutylvinylether) or an acrylate is conveniently reacted at a temperature of about -50 to 20C and in the presence of a reaction solvent and catalyst of the types indicated above.
Suitable vinyl polycyclic aromatic monomers obtainable and usable in accordance with the present invention are reported, for instance, in Table l with respect to formula l-lV and some polymers exemplified in Table ll.
The examples below are intended to illustrate various preferred embodiments of the instant invention.
EXAMPLE I (C-l) About. 1 mole of commercially obtained and chromatographically purified l,2 benzanthracene is dissolved in methylene chloride at about 0C and admixed with about an equimolar amount of SnCl 0.12 mole of a, a-dichloromethyl ether is then added slowly with continuous stirring for about 2 hours, the mixture being maintained at ambient temperature at least until HCl is no longer evolved. The resulting aldehyde intermediate product is then hydrolyzed and recovered. 0.5 Mole of the aldehye is then contacted with exact equimolar amounts of Triphenylphosphine at about 0C for 1 hour to obtain the vinyl monomeric product. This product is recovered and identified as IO-Vinyl-benzanthracene. The compound is reported in Table l as C-l.
EXAMPLE ll (C-l) Example I is repeated with the exception that the aldehyde is obtained by reaction with HC(Cl) OC .,H as a formylating agent in place of a, a-dichloromethyl ether. The product is found to be identical with C-l.
EXAMPLE lll (C-l) The reaction of Example I is repeated with the exception that TiCl is utilized a catalyst to obtain the alde- EXAMPLE V (P-] hyde' The resulting vinyl intefrmediatc product 0.01 Mole of the 10- vinylbenzanthracene obtained lated, found to be identical with the product of Examin Example I is dissolved in ethyl ether and the P and reported as Table I belowmixed with about 500 ppm of BF; with constant stirring EXAMPLE W (05) 5 at a temperature of about 0C for about 3 hours. The resulting homopolymer is separated out and purified m The reaction of Example I IS repeated with the cxccpthe usual way, and Coded as in Table I] below tion that the polycyclic aromatic reactant is l-methyl-2.3-benzochrysene. The resulting 4-vinyl in- EXAMPLE VI (P'2) termediate product is isolated and reported as (-5 in It) The polymerization reaction of Example V is re- Table I below. peated with the exception that the reaction is allowed TABLE I l CH O A Compound Q Cata lvst Y C-l 1,2-benzanthracene HC O -CH SnCl H C l l, 2 benzanthracene C 0 18 C-1 1, 2-benzanthracene HC O 11 CH C-1 1 2-benzanthracene HC 0 CH TiCl C- l 1,2-benzanthracene HC CH 0 C H C 6dibenzanthracene H'C--- 0 CH SnCl C-4 l, 2, 5, 6-dibenzanthracene Hc- 0-- CH3 ic1 (cl) 2 c 5 l-me 'chyl-Z, 3benzochrysene 0 3 Snell} 0-"; 1-2, 3tne'thyl-bcnzochrysen 0'--- CH3 C11 to proceed in tet rahydrofuran at about 10C for 4' HP-2 and reported in Table I1 below.
EXAMPLE v (P53): Y
Whatis claimed is:
'l'.' A process for producing a vinyl substitued aromatic polycyclic compound of the formula The vinyl monomer identified as C-S .(Example lV) comprising contacting a corresponding reactant repreis reacted as in Example .V but with an equivalent sented by the formula: amount of SbCl asan initiator to obtain the polymeric material identified as P-3 and reported in Table ll be- O low, I I 10 with at least a-molar amount of a haloalkyl ether of the 5 EXAMPLE VIII (CP-l) formula Example V is repeated but with the addition of about 0.001 mole of isobutylvinyl ether to the 10- vinyl benzanthracene (C-l reactant and the reaction allowed to i5 proceed for about 6 hours at C. The resulting eopoly- Cl mer, identified as CP-l is isolated, purified and rei 2 ported in Table II below. i CH O TABLE ll Reaction MW Polymer Monomer Comonomer Solvent Initiator Temperature (Numerical 0 Average) HP C-l (Ex 1) CHci. BF 0 9.000 HP-Z C-l THF BF 10 25.000 HP-3 CHCL, ShCL, 15.000 CP-l C-l isobutyl Et0Et BF 0 40.000
vinyl ether (.00i mole) EXAMPLE IX in the presence of a catalytic amount of SnCl or TiCl Ten NESA glass plates identified respectively as 8-1 whgrem Q defined as aPolycychc group havmg at through 5-10 are coated on one side with a 0.5;/. block? fused rmg nude; and ing layer of cured epoxy resin and a 0.5;; amorphous A lndmduany defined as an alkyl gl'oupi selenium photoconductive layer applied thereto in the 9 Obtam a Correspondmg P y y aldehyde Intermeusual way by vacuumcondensation (10 Torr). (hate represented by the formula A. To plates S-l through S-5 there are applied overcoat layers of polymer 'P-l (Example V) in layers of O lO J. to about 30 in thickness.
B. To the plates identified as 8-6 through 8-10 are ap- 40 Q M CH plied overcoat layers varying from 10a to about 30p. of polyvinyl pyrene having a numerical average molecular and then contacting the aldehyde intermediate with a weight of about 10,000 The pyrene utilized is Commer reactive amount of a phosphme compound represented cially obtained, purified and polymerized by acylation by the formulae (ref. Vollman, Beeker, Corell and Streech; Justus Lie- (Y)3 p CH2 (YEP (-1 h1g5 Annalen Der Chemie: Vol. 531 (1937).
The respective plates are thin corona charged at 900 Whch defined as a P y or lkyl group; volt, exposed to a monochromic light source at 4000 A to OPtam the cprrespondmg vmyl Substltuted P at a flux of 2 X 10 photons/cm /sec. and tested for. Cych? Compoumlelectrical properties.* The results are reported in Table A Process of clam} 1 Wherem the catalyst Sncl4- m below 3. The process of claim 1 wherein Q is an asymmetric *P. Regensburger in Optical Sensitization of Charge Carrier Transpolycyclic aromatic radical having at least 4 fused ring port in PVK", Photochemistry and Plwmbiology 8, p. 429-40 (Noveml i 4. The process of claim 1 wherein A is individually TABLE defined as a lower alkyl group; and Y is a phenyl group.
5. The process of claim 2 wherein Q is a 1,2- sflmple (JV/dild-I EOW/IL) benzanthracene group.
S L3) '54 6. The process of claim 3 wherein Q is a 1,2- 5 2 2.00 .65 benzanthracene group. 2:: I 7. The process of claim 2 wherein Q is a l,2,5,6- 5.5 10:0 200 dibenzanthracene. 3:? 8. The process of claim 2 wherein Q is a chrysene ss :95 :90 g p 54; L60 1.30 9. The process of claim 2 wherein Q is a 2,3- 540 benzochrysene group. m 10. The process of claim 2 wherein Q is a 3,4-
2 X 10' Photonlcm' lscc. flux 7 4000 A monochromic light benzpyrene group.
Page 1 of 2 UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTTON PATENT NO. 3, 896, 184
DATED July 22 1975 |N\/ENTOR(S) J.A. Bergfjord R.W. Radler, R.P. Millonzi It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 1, line 7 delete "an" and insert --as--a Column 1, line 47, delete "describes" and insert -described--.
Column 2, line 2, delete "photo discharge and insert -photodischarge-.
Column 3, line 38, delete "asymetric and insert --asymmetric-.
Column 4, line 16, delete "Boron Trifluoride" and insert --boron trifluoride-.
Column 4, line 201 delete "tetrahydrofurane" and insert -tetrahydrofuran--.
Column 4, line 44, delete "About. 1 mole" and insert About .1 mole.
Column 4 line 53, delete "aldehye" and insert aldehyde-.
Column 4, line 54, delete "Triphenylphosphine" and insert -triphenylphosphine-.
Column 4, line 56, delete "lO-Vinyl-benzanthracene" and insert lO-vinylbenzanthracene.
Column 7, line 48, delete "4000A" and insert "40008".
Page 2 of 2 UNITED STATES PATENT AND TRADEMARK OFFICE CTIFICATE OF CORRECTION PATENT NO. 1 3, 896 I 184 DATED July 22, 1975 v rg omg JuA. Bergfjord, R.W. Radler, R.P. Millonzi It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 8 line 2, delete "vinyl substitued" and insert vinyl substituted--.
Signed and Sealed this sixth D y of January 1976 [SEAL] A ttest:
RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ufParenrs and Trademarks