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
  • G03G5/08—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being inorganic
  • G03G5/087—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being inorganic and being incorporated in an organic bonding material
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
  • C08L61/20—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen
  • C08L61/26—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic compounds
  • C08L61/28—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic compounds with melamine
• • 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
  • G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
  • G03G5/0528—Macromolecular bonding materials
  • G03G5/0532—Macromolecular bonding materials obtained by reactions only involving carbon-to-carbon unsatured bonds
  • G03G5/0539—Halogenated polymers
• • 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
  • G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
  • G03G5/0528—Macromolecular bonding materials
  • G03G5/0532—Macromolecular bonding materials obtained by reactions only involving carbon-to-carbon unsatured bonds
  • G03G5/0542—Polyvinylalcohol, polyallylalcohol; Derivatives thereof, e.g. polyvinylesters, polyvinylethers, polyvinylamines
• • 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
  • G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
  • G03G5/0528—Macromolecular bonding materials
  • G03G5/0532—Macromolecular bonding materials obtained by reactions only involving carbon-to-carbon unsatured bonds
  • G03G5/0546—Polymers comprising at least one carboxyl radical, e.g. polyacrylic acid, polycrotonic acid, polymaleic acid; Derivatives thereof, e.g. their esters, salts, anhydrides, nitriles, amides
• • 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
  • G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
  • G03G5/0528—Macromolecular bonding materials
  • G03G5/0532—Macromolecular bonding materials obtained by reactions only involving carbon-to-carbon unsatured bonds
  • G03G5/0553—Polymers derived from conjugated double bonds containing monomers, e.g. polybutadiene; Rubbers
• • 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
  • G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
  • G03G5/0528—Macromolecular bonding materials
  • G03G5/0557—Macromolecular bonding materials obtained otherwise than by reactions only involving carbon-to-carbon unsatured bonds
  • G03G5/0575—Other polycondensates comprising nitrogen atoms with or without oxygen atoms in the main chain

Definitions

• a preferred photo-conductor is zinc oxide, such, for example, as the photo-conductive zinc oxide sold by the New Jersey Zinc Company as Florence Green Seal 8.
• photo-conductors such as the oxides of antimony, aluminum, bismuth, cadmium, mercury, molybdenum, and lead; the iodides, selenides, sulfides or tellurides of these metals including zinc; selenium; arsenic trisulfide; lead chromate and cadmium arsenide have been suggested.
• the resinous vehicle forms an electrically-insulating binder for the photo-conductor.
• the coating material applied to the electrically-conducting or semi-conducting substrate consists of a suspension of the finely divided photo-conductor in an aqueous medium containing an uncured melamine-formaldehyde resin having at least two mols of formaldehyde per mol of melamine, preferably at least 3 to 4 mols of formaldehyde per mol of melamine and from 1 to 8 preferably about 3 parts by weight of photo-conductor per part of total resin solids, and after application of this suspension to the substrate the coating is heated to eifect curing of the melamineformal-' dehyde resin.
• a flexible substrate such as paper.
• the suspension of the finely divided photo-conductor also contains a thermoplastic resin in amount of from 10% to preferably 35% to 55%, by weight of thermoplastic resin based on the weight of total resin solids.
• the present invention involves the application to the substrate of a suspension containing on a dry basis (not including the water) from 2 to 50, preferably 7 to 35, parts by weight of uncured melamineformaldehyde resin, 0 to 40, preferably 6 to 30, parts by weight of thermoplastic resin and 50 to 88, preferably 50 to 85, parts by weight of photo-conductor.
• the resultant electrophotographic recording member has the finely divided photo-conductor particles embedded in an electrically-insulating layer consisting of the melamine-formaldehyde resin alone or uniformly blended with the thermoplastic resin, when the latter resin is employed, which layer is firmly bonded with the substrate.
• the electrophotographic recording member has excellent electrophotographic properties, including low or long-time dark decay, at least as good as products made by organic solvent processes.
• the substrate paper is preferred, including high wet strength paper coated or uncoated, having a thickness of from 3 to 6 mils.
• Other electrically-conductive or semi-conductive materials may be used, such, for example, as plastic films including cellophane, cloth, and metallic foils, e.g., aluminum and copper foils.
• the melamine-formaldehyde resin used may be dimethylol melamine (e.g., Resloom HP of Monsanto- Chemical Co.); dimethyl trirnethylol melamine (Aerotex M-3 or Parez 613 of American Cyanamid Co.); trimethylol melamine (Aerotex 605 or Parez 607 of American Cyanamid Co.); tetramethylol melamine (Resloom HP Special, Monsanto Chemical Co.); tetramethyl pentamethylol melamine (Resloom LC-48, Monsanto Chemical Co.); tetramethyl hexamethylol melamine; pentamethyl pentamethylol melamine; pentamethyl hexamethylol melamine; other alkylated melamine formaldehyde resins; or mixtures of such resins.
• dimethylol melamine e.g., Resloom HP of Monsanto- Chemical Co.
• All of the above melamine formaldehyde resins contain at least 2 mols of formaldehyde per mol of melamine. It will be appreciated that the resins may be produced by reacting melamine with formaldehyde polymers or aqueous or alcoholic solutions of formaldehyde or formaldehyde polymers and that the reference to the number of mols of formaldehyde is to the number of mols present in the cured resin irrespective of the source of the formaldehyde. 2
• the melamine-formaldehyde resin should be in a watersoluble condition, i.e., uncured or partially cured to a stage where it is still appreciably water-soluble when applied to the substrate alone or in admixture with the thermoplastic resin. It may be used with or Without a hydearid thermoplastic resin.
• curing catalysts are zinc chloride, magnesium chloride, ammonium chloride, acids such as acetic or hydrochloric acid, phenyl biguanide hydrochloride, and diarnmonium-phosphate. Only a small amount of the catalyst need be employed, enough tolcatalyze the curing of the resin.
• melamine-formaldehyde resin usually from 1% to 5% by weight based on the weight of melamine-formaldehyde resin will sufiice.
• the melamine-formaldehyde resin may be used alone when coating less flexible substrate such as metal foils or plastic films.
• the ,thermoplas'ticresin should be used along with the mel-' amine formaldehyde resin; by so doing, cracking of the resin coating'u'pon flexureof the substarate is minimized, if not completely prevented.
• thermoplastic resin should be compatible with the melamine-formaldehyde resin and blend therewith. By employing the mixture, a resin coating resultswhich has good electrically-insulating" properties, is tough and ad heren't t0 the substrate, particularly paper, and is not too brittle, i.e., will not crack or peel when the paper or other flexible substrate is flexed or bent.
• thermoplastic resins which can be used are:
• Preferred'resin mixtures are mixtures of Parez 613 and Gelva 8-55 in amount of from 35% to 55% by Weight or the Ge lva s-ss based on the weight of total resin formaldehyde resin with or without the aid of a dispersing agent such as the alkali metal salts of alliyl naphthalene sjulfonicacids (Daxad No. llpf Dewey and Almy Co.,'
• the resultant dispersion is then mixed with an emulsion of the thermoplastic resin in water or a dispersion of the thermoplastic resin in water, in which dispersion the resin particles are in extremely finely divided, e.g., colloidal, form so that they will blend readily with the melamine-formaldehyde resin.
• the melamine-formaldehyde resin may be blended with the aqueous emulsion or. dispersion of the thermoplastic resin and the photo-conductor added to the mixture while agitating.
• the coating mixture thus prepared contians from 1 to 43 parts of resin solids (melamine-formaldehyde, or mixture of melamine-formaldehyde and thermoplastic resin), from 10 to 85 parts of water, and from 10 to 75 parts of photoeconductor, with the ratio of photo-conductor to resin solids within the ranges of l to l to 8 to 1;
• the coating layer applied to the substrate may have any de- 4. sired thickness; usually a thickness within the range of .2 to 1 mil gives satisfactoryresults.
• the coated substrate is subjected to a curing and drying treatment; For example, itmay be passed through a curing oven maintained at the curing temperature. Curing maybe effected at any temperature above about 180 F. and below the temperature at which'charring or damage to the subtrate may take place. Preferred curing temperature is within the rangeof 180 F. to 300 F., preferabiy about 240 F.250 F. During this curing treatmentresidual moisture is removed from the insulating layer.
• the time of cure will depend on the temperature and whether or not a catalyst is'employedi Satisfactory cure can be obtained in from 1 0 5 minutes at 240 F.-250 F. without a curing catalyst in the coating mixture.
• the curing time may vary from 1 to 15 minutes; at 180 F. a longer curing time within this range is used and at about 250 F. ashorter curing time of about 1 to 5 minutes is used.
• the resultant electrophotographic recording element particularly when made with a paper substrate, has the electrically-insulating resin layer firmly bonded to the substrate and also has excellent electrical properties.
• the dielectric properties are at least as good as products made employing organic solvent resin solutions, yet the procedure of the present invention involves none of the disadvantages inherent in any procedure involving the use of such organic solvents.
• Example I 600 parts of zinc oxide are dispersed in parts of Parez 613 (80% solids, 20% water) employing 2 parts of a dispersing agent (Daxad No. 11). While agitating this dispersion 325 parts of polyvinyl acetate resin emulsion (51% solids, 49% water) (Resyn 25-1234) are added. After thorough mixing for about 45 minutes the dispersion is coated on paperto a thickness of 0.005 inch. The coated paper is then heated at 240 F.--250 F. for
• An electrophotographic recording element is thus produced at least as good as the zinc oxide coated paper made from a solution of silicone resin in a toluene-xylene mixture.
• Example II This example difiers from Example I chiefly in that the thermoplastic resin employedis Resyn 2-507 and the proportion of the two resin constituents is 25% melamineformaldehy'de resin to Resyn 2507. The results are the same as in Example I.-
• Example III All of the photo-conductor. An eminently satisfactory electrophotographic recording element results.
• Example V This example differs from Example I in that it involves the use of lead sulfide as the photo-conductor and the use of a resin mixture of Parez 613 and Latex 512R containing equal parts of each resin in a ratio of 1 part resin solids, 1 part water, and 2 parts of the. photo-com;
• Example VI This example differs from Example I in that it in volves the use of zinc sulfide as the photo-conductor and the use of a resin mixture of Parez 613 and Latex 512R containing equal parts of each resin in a ratio of 1 part resin solids, 1 part water, and 2 parts of the photoconductor. An eminently satisfactory electrophotographic recording element results.
• Example VIII involves the use of 300 parts of vinylidene chloride vinyl chloride copolymer.
• Example IX involves the use of '350'parts of vinylidene chloride acrylonitrile copolymer, Example X involves the use of acrylonitrile butadiene copolymer and
• Example H involves the use of Lytron 680, interpolymers of Z-ethylhexyl acrylate, styrene acrylonitrile and methacrylic acid. Otherwise the conditions are the same and the results substantially the same.
• the present invention provides a process of producing electrophotographic recording members free of the objections inherent in the use of organic solvents, which process requires no special coating equipment for its practice and no special safety or health precautions, and which process results in electrophotographic recording members having good electric-a1 properties including low dark decay and good insulating properties and also having the electrically-insulating resinous layer firmly bonded to the substrate.
• the method of producing an electrophotographic recording member which comprises coating a substrate with a suspension of finely divided electrophotographic photoconductor from the group consisting of the oxides, iodides, selenides, sulfides and tellurides of zinc, antimony, aluminum, bismuth, cadmium, mercury, molybdenum and lead, selenium, arsenic trisulfide, lead chromate and cadmium arsenide in an aqueous medium containing from 45% to 65% by weight of total resin solids present of a melamine-formaldehyde resin having at least 2 mols of formaldehyde per mol of melamine condensed therein and from 35% to 65 by Weight of total resin solids present of a thermoplastic resin from the group consisting of vinyl acetate homopolymers, vinyl acetate octylacrylate copolymers, vinyl acetate vinyl chloride copolymers, vinylidene chloride vinyl chloride, copolymers
• the method of producing an electrophotographic recording member which comprises coating a substrate with a suspension of finely divided zinc oxide photoconductor in an aqueous medium containing from 45% to 65% by weight of total resin solids present of a melamine-formeldehyde resin having at least 2 mols of formaldehyde per mol of melamine condensed therein and from 35% to 65% by weight of total resin solids present of a thermoplastic resin from the group consisting of vinyl acetate homopolymers, vinyl acetate octylacrylate copolymers, vinyl acetate vinyl chloride, copolymers, vinylidene chloride vinyl chloride copolymers, vinylidene chloride acrylonitrile copolymers, acrylonitrilebutadiene copolymers, styrene-butadiene copolymers, interpolymers of 2-ethylhexyl acrylate, styrene, acrylonitrile and methacrylic acid
• An electrophotographic recording member comprising a substrate having firmly bonded thereon a continuous photo-conductive insulating layer comprising electrophotographic photo-conductor particles from the group consisting of the oxides, iodides, selenides, sulfides and tellurides of zinc, antimony, aluminum, bismuth, cadmium, mercury, molybdenum and lead, selenium, arsenic trisulfide, lead chromate and cadium arsenide imbedded in a resinous layer, the resinous material of said layer imparting the electrically-insulating properties thereto consisting essentially of melamine-formaldehyde resin having at least 2 mols of formaldehyde per mol of melamine condensed therein, and the ratio of said electrophotographic photo-conductor particles to said melamineformaldehyde res-in present in said layer, on a dry basis, being within the range of from 1 to 1 to 8 to 1 parts by weight.
• An electrophotographic recording member comprising a substrate having firmly bonded thereon -a continuous photo-conductive insulating layer comprising zinc oxide photoconductor particles imbedded in a resinous layer, the resinous material of said layer imparting the electrically-insulating properties thereto consisting essentially of melamine-formaldehyde resin having at least 2 mols of formaldehyde per mol of melamine condensed therein, and the ratio of said electrophotographic photoconductor particles to said melamine-formaldehyde resin present in said layer, on a dry basis, being within the range of from 1 to 1 to 8 to 1 parts by weight.
• An electrophotographic recording member comprising a substrate having firmly bonded thereto a continuous photo-conductive insulating layer comprising electrophotographic photo-conductor particles from the group consisting of the oxides, iodides, selenides, sulfides and tellurides of iinc, antimony,-aginanum, bismuth, cadmium,-
• An electrophotogr'aphic'recording member comprising a substrate having firmly bonded thereto a continuous photo-conductive insulating layer comprising zinc oxide photo-conductor particles imbedded in a resinous layer consisting of from 45% to 65% by weight of total resin solids present, on a dry basis, of melamine-formaldehyde resin having at least 2 mols of formaldehyde per mol of melamine condensed therein and from 35% to 55 by Weight of total resin solids present of at least one resin from the group consisting of vinyl acetate homo polymers, vinyl acetate octylacrylate co'polymer's, vinyl acetate vinyl chloride copolymers, vinylidene chloride vinyl chloride copolyrners, vinyliderie chloride acrylonitrile copolyrners, acrylonitrile-butadiene copolymers, sty-' rene-butadiene copolymers
• An electro'photogfaphie recording member comprising a paper base having firmly bonded thereto a condensed photo-conductive insulating layer comprising zinc oxide photo-conductor particles imbedded in a resinous layer consisting of a cured mixtureof melamine-formaldehyde resin having at least 2 mols of formaldehyde per mol of melamine condensed therein and an interpolyrner of Z-ethylhexyl acrylate, styrene, acrylonitrile and methacrylic acid in the proportions of from 35% to 55% of said interpolymer to 65% to 45% by weight of said melamine-formaldehyde resin, the ratio of zinc oxide to resin solids, on a dry basis, in said layer being within the range of from 1 to 1 to 8 to 1 parts by Weight.
• the method of producing an electrophotographic recording member which comprises coating a substrate with a suspension of finely divided lectrophotographic photo-conductor from the group consisting of the oxides, iodides, selenides, sulfides and tellurides of Zinc, antimony, aluminum, bismuth, cadmium, mercury, molyb denum and lead, selenium, arsenic trisulfi'de, lead chro' mate and cadmium a-rsenide in an aqueous medium containing a melamine-formaldehyde resin having at least 2r'nols of formaldehyde" per mol of melamine condensed therein, the ratio of said photo-conductor to said mel-' s'ulating-la'yer having the photo-conductor particles em-- bedded therein, said layer being continuous and firmly bonded to the substrate;
• the method ofproducing an electrophotographic recording member which comprises coating a substrate with a suspension of finely divided zinc oxide photoconductor in an aqueous medium containing a melamineforrnaldehyde resin having at least 2 mols of formaldehyde per mol of melamine condensed therein, the ratio of said zinc oxide to said melamine-formaldehyde resin in said suspension, on a dry basis, being within the range of from 1' to 1 to 8 to 1 parts by weight, the said melamine formaldehyde resin being the essential resinous constituent ofsaid aqueous medium imparting the electrically-insulating propertiesto the coating layer formed therefrom, and thereafter heating the coated substrate to efiect curing of the melamine-formaldehyde resin and produce a photo-conductive insulating layer having the zinc oxide particles embedded therein, said layer being continuous and firmly bonded to. the substrate.

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• Photoreceptors In Electrophotography (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)

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• 1958
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• 1959
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• 1962
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