US3698895A - Photoelectrostatic members - Google Patents

Photoelectrostatic members Download PDF

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Publication number
US3698895A
US3698895A US74507A US3698895DA US3698895A US 3698895 A US3698895 A US 3698895A US 74507 A US74507 A US 74507A US 3698895D A US3698895D A US 3698895DA US 3698895 A US3698895 A US 3698895A
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US
United States
Prior art keywords
photoelectrostatic
photoconductive insulating
materials
resin
insulating material
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 - Lifetime
Application number
US74507A
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English (en)
Inventor
Ronald B Schultz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AB Dick Co
Original Assignee
Multigraphics Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Multigraphics Inc filed Critical Multigraphics Inc
Application granted granted Critical
Publication of US3698895A publication Critical patent/US3698895A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/62—Polymers of compounds having carbon-to-carbon double bonds
    • C08G18/627—Polymers of hydroxylated esters of unsaturated higher fatty acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/30—Low-molecular-weight compounds
    • C08G18/36—Hydroxylated esters of higher fatty acids
    • 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
    • G03G5/0535—Polyolefins; Polystyrenes; Waxes
    • 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
    • G03G5/0571—Polyamides; Polyimides
    • 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

  • Photoelectrostatic members are useful in the electrostatic copying process wherein a conductive base, such as metal or paper having a photoconductive insulating layer thereon is electrostatically charged in the dark.
  • the charged photoconductive layer is then exposed to a light image.
  • the light causes the photoconductive insulating material, such as zinc oxide or selenium, to become electrically conducting and the charge is dissipated rapidly from the surface of the photoconductive insulating layer to the conductive base or substrate, the rate of charge dissipation being proportional to the intensity of the light to which any given area is exposed.
  • the surface of the photoconductive insulating layer is contacted in the dark with electroscopic particles.
  • the powder image can then 7 be transferred to a sheet of transfer material to form a print, or, where the base material is a relatively inexpensive material such as paper, the powder image may be fixed thereto directly to form a print.
  • the photoconductive insulating material in fine particle form has been dispersed in organic resin binders such as ethyl cellulose, polystyrene, nitrocellulose, vinyl polymers, chlorinated rubber, acrylic resins and similar materials. Silicones have been mentioned as satisfactory binder materials (Middleton et a1. Pat. No. 3,121,006). Reaction products of polyester resins with organic diisocyanates have also been recommended as binding agents for photoconductive insulating materials in photoelectrostatic materials .(Bunge et al. Pat. No. 3,025,160). Polystyrene is described as a binder (Sugarman et al. Pat. No. 2,862,815).
  • photoelectrostatic materials or members in the form of electrically conductive bases or substrates coated with a thin layer of a photoconductive insulating material in a resin binder which is a combination formed of a polyhydroxy ester with an organic polyisocyanate have particularly desirable properties which make them of value in photoelectrostatic processes.
  • This resin binder combination has the advantages of providing high light sensitivity (rapid light response rate) to the photoelectrostatic materials with the ability to reproduce high fidelity and high quality tonal images with improved print density.
  • this resin binder provides photoconductive insulating layers which have desirable dark decay rates and dark voltage retention characteristics.
  • the light sensitivity of the photoelectrostatic materials prepared in accordance with this invention is at least 1.6 times as great as the sensitivity of photoelectrostatic layers formulated with silicone, silicone-alkyd or uralkyd resin binders.
  • the speed of these photoelectrostatic materials is at least 1.25 times that of similar materials formulated with silicone-alkyd resins and at least 2.0 times that of the' bility toward pre-exposure, and performance in lithographic applications.
  • the various combinations of polyhydroxy esters with organic polyisocyanates produce a special group of polyurethane resins which are compatible with large quantities of zinc oxide pigment and are more effective than uralkyd resins in photoelectrostatic papers. They are substantially lower in cost than are the silicone resins and have significant commercial advantages over such resins.
  • the photoelectrostatic members produced with these resins have the ability to reproduce high fidelity and high quality tonal images with improved print density when compared to prior art resin binders.
  • the photoelectrostatic materials produced with such resin binders have desirable dark decay rates and dark voltage retention.
  • the photoelectrostatic members which comprise this invention comprise a base or substrate which is electrically conducting and has a resistivity in the range from to 10 ohm-centimeters and preferably in the range of 10 to 10 ohm-centimeters.
  • the substrate or base can be formed of metals such as aluminum, copper and steel, of metal foils such as aluminum and tin, and of paper, plastic, cloth and other materials having the proper electrical resistivity.
  • the electrical resistivity thereof may be adjusted by the addition of conductivity-increasing materials such as inorganic salts and by control of humidity.
  • the resin binder of the present invention is made by interaction of an organic polyisocyanate with an aliphatic monocarboxylic fatty acid ester of a polyhydric alcohol containing at least three hydroxyl radicals, wherein the polyhydric alcohol portion of said ester contains at least two free hydroxyl radicals.
  • the resin binders of this invention have molecular weights ranging from about 7,000 to 30,000 or higher.
  • the polyurethane resins are produced from hydroxy esters by reaction with the organic polyisocyanate, the isocyanate groups reacting with available hydroxyl radicals of the esters to produce urethane linkages.
  • the hydroxy esters from which the polyurethanes are produced include fatty acid esters of polyols which contain three or more hydroxyl radicals.
  • Suitable acids include those containing 10 to 24 carbon atoms, such as oleic, linoleic, stearic, palmitic, lauric, linolenic and ricinoleic. These acids can be obtained from vegetable oils such as corn, peanut, cottonseed, palm, linseed, soya, safllower, castor and dehydrated castor oils.
  • the polyols include glycerol, trimethylolethane, mannitol, trimethylolpropane, sorbitol and pentaerythritol. They are partially esterified with the fatty acid to produce compounds having two or more free hydroxyl radicals in the ester moieties.
  • the hydroxy esters can be produced by esterification of the monocarboxylic acid and the polyol by conventional procedures. Acid chlorides and anhydrides can be used in lieu of the acids.
  • the preferred procedure is transesterification whereby a source of fatty acid such as a vegetable oil is reacted with a polyol in the presence of a transesterification catalyst such as an inorganic acid (e.g., HCl or H 50 or a weak base such as an alkali metal or alkaline earth metal salt of an organic acid (e.g., sodium acetate or calcium acetate).
  • a transesterification catalyst such as an inorganic acid (e.g., HCl or H 50 or a weak base such as an alkali metal or alkaline earth metal salt of an organic acid (e.g., sodium acetate or calcium acetate).
  • the product when a vegetable oil such as cottonseed oil is reacted with a mole of pentaerythritol, the product is a mixture of monoglycerides of palmitic, oleic, linoleic, stearic and other fatty acids present in cottonseed oil and monoand di-esters of pentaerythritol and the same fatty acids.
  • This mixture of hydroxy esters contains (on the average) at least two hydroxyl radicals per molecule.
  • hydroxy esters are produced by known methods from the carboxylic acids and the polyhydric alcohols, such as by thermal esterification in an inert atmosphere and under reduced pressure at elevated temperature.
  • the hydroxy esters are reacted with organic polyisocyanates to produce polyester-polyurethane resins.
  • the amount of polyisocyanate used is 10% to 40% of the weight of the hydroxy ester.
  • the hydroxy ester and the polyisocyanate are heated together, preferably in an inert atmosphere, whereby the isocyanate radicals react with the free hydroxyl radicals to produce urethane linkages.
  • a wide range of organic polyisocyanate materials can be used. The common and preferred materials are tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate or mixtures thereof.
  • Vinyl aromatic polymers can comprise 5% to 35% of the total resin binder weight and can be chosen from polymers of styrene, divinylbenzene, vinyltoluene, divinyltoluene, methylstyrene, 2,4-dimethylstyrene, vinylnaphthalene, phenylstyrene, vinylfluorene and related vinylarene polymers, as well as related vinyl aromatic polymers such as those of N-vinylcarbazole, N,N-diphenylacrylamide and vinyldibenzofuran.
  • resin binders can be made by the interaction of a vinylaryl monomer with a polyhydric alcohol ester having multiple pendant polyethylenically unsaturated fatty acid ester groups as Well as unreacted hydroxyl groups on the polyol.
  • the vinylaryl groups attach to the hydroxy ester through free radical polymerization and partial crosslinking of some of the sites of unsaturation on the vinylaryl groups and fatty acid ester groups leaving unaffected the remaining hydroxyl groups on the polyol moiety.
  • the organic polyisocyanate is then reacted with the remaining free hydroxyl radicals on the ester to form urethane linkages.
  • the resulting resin is a polyvinyla'ryl-polyurethane resin having pendant fatty acid ester groups wherein the polyvinylaryl groups are chemically bonded to some of the sites of ethylenic unsaturation of said fatty acid groups and the urethane linkages are formed on the free hydroxyl radicals of the polyhydric alcohol.
  • the remaining sites of unsaturation on the fatty acid groups will crosslink by air oxidation after application to the substrate.
  • These resin binders preferably have molecular weights ranging from about 10,000 to 20,000.
  • the polyurethane resins are dissolved in a suitable solvent, such as naphtha, toluene or xylene or mixture of toluene or xylene with butanol, and the finely divided photoconductive insulating material (e.g., zinc oxide) is admixed with good agitation with the resin solution, preferably in a ball mill or similar mixing and grinding equipment.
  • a suitable solvent such as naphtha, toluene or xylene or mixture of toluene or xylene with butanol
  • the finely divided photoconductive insulating material e.g., zinc oxide
  • the resin solution preferably in a ball mill or similar mixing and grinding equipment.
  • a polyurethane resin produced from 24.5% tolylene diisocyanate and 75.5% unsaturated polyester resin having a molecular weight of approximately 10,000 and an acid number of less than 10 was dissolved in xylene to produce a coating solution containing 50% resin solids by weight.
  • .R is the aliphatic radical of a fatty acid of the formula RCOOH
  • X is a polyol nucleus
  • n is an integer from 1 to 3, inclusive
  • m is an integer from 2 to 3, inelusive.
  • the hydroxy esters are usually mixtures of esters formed by esterification of part of the hydroxyl radicals of the polyols with fatty acids. The esterification is so controlled that at least two free hydroxyl radicals (on the average) remain on the polyols. These hydroxyl radicals subsequently react with the organic polyisocyanate to form polyurethane resins in accordance with known procedures.
  • EXAMPLE 1 A mixture of 53 parts of soya oil and 12.5 parts of technical grade pentaerythritol (about 86% monopentaerythritol and balance polymers) was heated to about 200 C. in a nitrogen atmosphere. Then 0.1 part of calcium acetate was added and the mixture heated to 240 C. with agitation until the acid number of the mixture was less than 10. The mixture was cooled, diluted with 100 parts of toluene and warmed to 75 C. About 20 parts of tolylene diisocyanate (:20 2,4-isomer:2,6-isomer) was added with agitation at a rate such that the temperature of the reaction mixture did not exceed C.

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  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Photoreceptors In Electrophotography (AREA)
US74507A 1967-02-24 1970-09-22 Photoelectrostatic members Expired - Lifetime US3698895A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US61835267A 1967-02-24 1967-02-24
US7450770A 1970-09-22 1970-09-22

Publications (1)

Publication Number Publication Date
US3698895A true US3698895A (en) 1972-10-17

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Family Applications (1)

Application Number Title Priority Date Filing Date
US74507A Expired - Lifetime US3698895A (en) 1967-02-24 1970-09-22 Photoelectrostatic members

Country Status (4)

Country Link
US (1) US3698895A (en)van)
BE (1) BE711100A (en)van)
FR (1) FR1557206A (en)van)
GB (1) GB1206835A (en)van)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5123738A (en)van) * 1974-07-30 1976-02-25 Toyo Ink Mfg Co
EP1277089A4 (en) * 2000-04-12 2006-03-01 Lexmark Int Inc LOAD GENERATION LAYER CONTAINING AT LEAST ONE TITANATE AND PHOTOCONDUCTORS

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5123738A (en)van) * 1974-07-30 1976-02-25 Toyo Ink Mfg Co
EP1277089A4 (en) * 2000-04-12 2006-03-01 Lexmark Int Inc LOAD GENERATION LAYER CONTAINING AT LEAST ONE TITANATE AND PHOTOCONDUCTORS

Also Published As

Publication number Publication date
FR1557206A (en)van) 1969-02-14
GB1206835A (en) 1970-09-30
BE711100A (en)van) 1968-07-01

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