Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/087—Binders for toner particles
  • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • G03G9/08773—Polymers having silicon in the main chain, with or without sulfur, oxygen, nitrogen or carbon only
• • 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
  • G03G5/0557—Macromolecular bonding materials obtained otherwise than by reactions only involving carbon-to-carbon unsatured bonds
  • G03G5/0578—Polycondensates comprising silicon atoms in the main chain
• • 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
  • G03G5/0596—Macromolecular compounds characterised by their physical properties
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/087—Binders for toner particles
  • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • G03G9/08755—Polyesters
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/087—Binders for toner particles
  • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • G03G9/08759—Polyethers
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/087—Binders for toner particles
  • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
  • G03G9/08791—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775 characterised by the presence of specified groups or side chains

Definitions

• the present invention relates to dry toner particles used as image forming species in electrically or magnetically based imaging methods as, e.g. electro(photo)graphy, magnetography, direct electrostatic printing (DEP), ionography, etc, wherein the toner particles comprise copolymers comprising polysiloxane moieties.
• the invention relates also to a simple method for preparing a distinct class of copolymers comprising polysiloxane moieties.
• the invention further relates to protective layers comprising such copolymers.
• Copolymers comprising polysiloxane moieties are known to possess desirable properties. Coatings of such copolymers are very abhesive and water repellent, while remaining fairly scratch resistant. The copolymers do also possess desirable slip and anti-sticking properties.
• polysiloxane moieties are polysiloxane-polyethers and are di-hydroxy-terminated.
• the incorporation of the polysiloxane moieties in the polyester proceeds by polycondensation of the polysiloxane diol together with di-carboxylic acids and other diols.
• a thermal transfer donor element comprising an anti-sticking backing layer, wherein an organopolysiloxane-polyurea is incorporated.
• These copolymers are prepared by the reaction of a silicone diamine, a di-isocyanate and a diamine or dihydroxy chain extender.
• copolymers comprising polysiloxane moieties in toner particles used as image forming species in electrically or magnetically based imaging methods is also known.
• Said copolymers are mainly used to overcome adhesion problems typical for toner particles.
• the adhesion of toner particles to each other, diminishing fluidity of the toner and diminishing resolution in the final image is one of the problems addressed by using copolymers comprising polysiloxane moieties.
• An other problem addressed by the use of said copolymers is, in a multi-component developer, the adhesion of toner particles to carrier particles.
• the problem of "hot-offset" in imaging methods using a heated fixing roller can be overcome by using the copolymers described above.
• DE-OS 22 53 402 it is disclosed to use a block copolymer comprising a hard block and a weak block to overcome problems with hot-offset.
• the choice of the preferred hard and weak blocks depends more on the elasticity modulus and/or tensile strength than by the chemical nature of the hard and weak blocks.
• a copolymer comprising poly(bisphenol A-carbonate) as hard block and polydimethylsiloxane as weak block is disclosed.
• LSA low surface adhesion
• toner particles comprising a mixture of polyester resin and a polyester resin comprising polysiloxane chains (cross-linked or not) as toner resin, are very well suited for use in imaging systems using a hot roller fusing step. It is also stated, in e.g. EP-A 298 279, that the quality of the blending of both resins, during the toner preparation, influences the quality of the toner particles and the amount of polysiloxane modified polyester needed in the toner particles.
• EP-A 298 279 the preparation of a random graft polymer of a multifunctional organosiloxane polymer, namely ⁇ , ⁇ , ⁇ -aminopropyl poly(dimethyl-co-methoxy- ⁇ -aminopropyl siloxane) and a polyester is described.
• the reaction proceeds at 220 °C for 2 hours followed by another hour reaction at 240 °C and under reduced pressure.
• the incorporation of polysiloxane moieties in polyesters over an amino group is not so desirable for polysiloxane modified resins used as toner resin, since polyester tend to be negatively charged by tribo-electric contact and the aminogroups diminish the negative chargeability of the polysiloxane modified resin.
• Addition polymers comprising polysiloxane moieties are described in, e.g., EP-A 300 426, EP-A 361 522, EP-A 413 604 and EP-A 441 276.
• EP-A 300 426 the preparation of addition polymers of unsaturated polysiloxanes and ⁇ , ⁇ ethylenically unsaturated monomers is described. This reaction gives rise to graft-polymers where the polysiloxane moieties are contained in side chains. The product is used as lubricant in electrophotographic photosensitive members.
• EP-A 361 522 it is disclosed to produce a macromonomer by introducing a vinyl silane in a terminal diol-type polydimethylsiloxane and radical polymerizing said macromonomer with, e.g. vinylacetate or other ⁇ , ⁇ ethylenically unsaturated monomers.
• EP-A 581 150 it is disclosed to form a releasing agent for blending in to toner particles by reacting an organic polysiloxane having an hydroxyl group or an epoxy group with an ethylenically unsaturated dicarboxylic acid grafted polyolefin or with a reaction product of said grafted polyolefin and an active hydrogen atom containing compound selected from the group consisting of an alcohol, an amine and an aminoalcohol.
• the polyolefin used in the reaction is preferably a low molecular weight polyolefin.
• This release agent is basically a crystalline polymer and by mixing this releasing agent with toner resins, the toner resin/releasing agent system shows incompatibilities, since the releasing agents in this disclosure are very apolar and since, due to the crystallinity of this releasing agent, the interfacial adhesion to the toner resin is very low.
• the releasing agent tends to break out of the mixture, thus forming free particles of releasing agent during the pulverizing step.
• This free particles of releasing agent can not easily be controlled and are inevitably introduced together with the toner particles in the developer, thus inducing unstable behaviour of the developer.
• the objects of the invention are realized by providing dry toner particles comprising a toner resin and optionally a pigment, characterised in that said toner resin comprises more than 3 % by weight with respect to the total resin content of a polysiloxane modified resin comprising polysiloxane moieties (PS) and other polymeric moieties (POL), wherein
• PS polysiloxane moieties
• POL polymeric moieties
• said other polymeric moieties are derived from polymers having a Tg > 40 °C.
• said toner resin comprises more than 50 % by weight, with respect to the total resin content, of said polysiloxane modified resin.
• said toner resin consists of one or more of said polysiloxane modified resins.
• the need for providing toner particles with good offset resistance is widespread in the art, and has also been addressed by introducing polymeric releasing agents comprising siloxane moieties in the toner particles.
• Examples of such toner particles can be found in the above referenced disclosures DE-OS 22 53 402. US 5,089,547, EP-A 298 279 and EP-A 581 150.
• the toner particles described in these disclosure do comprise a low amount of the releasing agent (resulting in less than optimal abhesive properties of the particles), or the releasing agent influences the physical properties, e.g., Tg (glass transition temperature), Tm (melting temperature), melt viscosity, etc., of the toner particles (limiting the usefulness of the particles to specific uses).
• the releasing agents, described in the references cited above can not easily and permanently be incorporated in toner particles. The reason therefore seems to be the high crystallinity of the releasing agents and the low compatibility with commonly used toner resins.
• polymers comprising oxygen containing groups in the main chain can be cited polyesters, polyesteramides, polyolefine comprising ether groups, etc..
• polymers having oxygen containing groups attached to the main chain are, e.g., addition polymers comprising moieties derived from esters of unsaturated carboxylic acid (e.g. esters of acrylic acid).
• esters of unsaturated carboxylic acid e.g. esters of acrylic acid.
• POL polymeric moieties
• the polysiloxane modified resins comprise polymeric moieties (POL) derived from polymers having a Tg > 40 °C or even > 50 °C, it is possible to maximize the hot-offset resistance and abhesivity of the toner particles by using one or more of said polysiloxane modified resins as toner resin. I.e. it was not necessary to mix said polysiloxane modified resins with other known toner resins (e.g. polycondensation polymers or addition polymers) to prepare toner particles with high mechanical strength at room temperature and with high abhesivity.
• POL polymeric moieties
• Polysiloxane modified resins useful to be incorporated in toner particles according to the present invention, comprise preferably polysiloxane moieties (PS) corresponding to general formula V : wherein : X corresponds to : or to or to or to Y has the same meaning as X, or represents a lower (C1 to C4) alkyl group, Z' and Z'' are equal or different and represent a lower (C1 to C4) alkyl group or an aryl group, 2 ⁇ m ⁇ 35, and 1 ⁇ n ⁇ 6.
• PS polysiloxane moieties
• polysiloxane modified resins for use in toner particles according to the present invention and comprising polysiloxane moieties (PS) and other polymeric moieties (POL), are prepared by a chemical reaction between carboxyl and/or hydroxyl groups comprised in the (co)polymer, giving the other polymeric moieties (POL) and epoxy groups terminating the polysiloxane, giving the polysiloxane moieties (PS).
• the toner particles, according to the present invention, comprising polysiloxane modified resins can be used in electrically or magnetically based imaging methods as, e.g. electro(photo)graphy, magnetography, direct electrostatic printing (DEP), ionography, etc.
• the toner particles according to the present invention can be magnetic toner particles, toners for use in multi-component developers, in non magnetic mono- component toners etc.
• Toner particles, according to the present invention, comprising polysiloxane modified resins are especially useful in the production of non magnetic mono-component toner particles, due to the good abhesive properties of said resins.
• the abhesive properties of the toner particles are already high, from the incorporation of 3 % by weight, with respect to the total toner resin, of polysiloxane modified polymers, on, it is preferred that in toner particles intended for non magnetic mono-component toner development, the toner resin consists of one or more polysiloxane modified resins.
• Non magnetic toner particles for non magnetic mono component development comprising polysiloxane modified resins, according to the present invention, can be used without the addition of said lubricants and/or abrasives.
• Toner particles comprising polysiloxane modified resins, according to the present invention, as constituent of the resinous matrix have a very high fluidity and low internal cohesion and adhesion, even without the need to use the well known measures to improve powder fluidity as e.g. the addition of known fluidity improvers (e.g. hydrophobic silica, titania, alumina, etc).
• fluidity improvers e.g. hydrophobic silica, titania, alumina, etc.
• the polysiloxane modified resins to be incorporated in toner particles, according to the present invention comprise preferably other polymeric moieties (POL), i.e. the non-polysiloxane moieties in the polysiloxane modified resin, derived from polymers having a Tg higher than 40 °C, more preferably higher than 50 °C.
• POL polymeric moieties
• the upper limit of the amount of polysiloxane moieties (PS) that can be introduced depends, apart from the amount of reactive sites present on the unmodified polymers , on the Tg of the unmodified polymers (the other polymeric moieties, POL) that are used to prepare the polysiloxane modified resins according to the present invention.
• Toner particles according to the present invention can comprise one or more polysiloxane modified resins, either alone or in combination with other resins, and can be used for dry development as well as for liquid development.
• the polysiloxane modified resins can (when necessary for a specific imaging technique), in toner particles according to the present invention, be mixed with other known toner resins, both polycondensation resins and addition polymerized resins e.g. unmodified polyesters, styreneacrylate polymers, etc..
• Toner particles, according to the present invention can comprise any normal toner ingredient e.g. charge control agents, pigments both colored and black, anorganic fillers, etc.
• a description a charge control agents, pigments and other additives useful in toner particles, comprising a polysiloxane modified resin according to the present invention, can be found in e.g. EP-A 601 235.
• Polysiloxane modified resins, according to the present invention, are especially useful as toner resin for coloured toners.
• Toner particles comprising a polysiloxane modified resin
• a multi-component dry developer can, when used in a multi-component dry developer, be mixed with any known carrier material.
• Known fluidity enhancers as e.g. hydrophobized silica, can be mixed with said toner particles.
• the toner particles can be used as a mono-component dry developer or mixed with carrier particles to form a multi component developer.
• toner particles comprising a polysiloxane modified resin (macromolecule), as toner resin, by melt kneading procedures followed by milling, or by a suspension process wherein the toner resin and toner ingredients are dissolved in an organic solvent, the solution dispersed in a medium wherein said organic solvent is insoluble, and finally the organic solvent is evaporated.
• a polysiloxane modified resin macromolecule
• Toner particles comprising a polysiloxane modified resin (macromolecule) as toner resin, can have an average volume diameter between 1 and 50 ⁇ m, preferably between 3 and 20 ⁇ m and more preferably between 3 and 10 ⁇ m.
• the particle size distribution of said toner particles can be of any type. It is however preferred to have a substantially Gaussian or normal particle size distribution (the normal distribution may show some skewness), either by number or volume, with a coefficient of variability (standard deviation divided by the average) ( ⁇ ) smaller than 0.5, more preferably of 0.3.
• the toner particles can have any shape, the particles can irregular, rounded, etc.
• polysiloxane modified resins useful to be incorporated in toner particles according to the present invention, are most preferably prepared by reacting (co)polymers comprising carboxyl and/or hydroxyl groups with polysiloxane compounds carrying at least one terminal epoxide group.
• the polysiloxanes that are preferred to prepare polysiloxane modified resins, for use in toner particles according to the present invention, and for forming the polysiloxane moieties (PS) therein, can be di-functional as well as monofunctional and correspond to general formula VI wherein : X' is Y' has the same meaning as X', or represents a lower (C1 to C4) alkyl group, Z' and Z'', which may be the same or different, represent a lower (C1 to C4) alkyl group or an aryl group, 2 ⁇ m ⁇ 35 and 1 ⁇ n ⁇ 6.
• Z' and Z'' have the same significance and represent a methyl or ethyl group and 5 ⁇ m ⁇ 30 and 2 ⁇ n ⁇ 4.
• the di-functional polysiloxane compounds used to prepare polysiloxane modified resins, according to the present invention corresponds to the formula VII and the mono-functional polysiloxane compounds used to prepare polysiloxane modified resins, according to the present invention, to formula VIII. wherein X' is or wherein X' is
• Epoxy terminated polysiloxane derivatives corresponding to the general formulae V to VIII, are commercially available from Th. Goldschmid AG, Essen, Germany under trade names TEGOMER E-Si 2130 AND TEGOMER E-Si 2330.
• Any polymer comprising carboxyl groups and/or hydroxyl groups can be used as polymer for the reaction with the epoxy terminated polysiloxane and for forming the other polymeric moieties (POL) in the polysiloxane modified copolymers, according to the present invention. It is preferred to use polymers (both polycondensation polymers and addition polymers) comprising oxygen containing groups.
• Polymers comprising oxygen containing groups are polymers that comprise oxygen containing groups either in the main chain or attached to the main chain.
• polymers comprising oxygen containing groups in the main chain can be cited polyesters, polyesteramides, polyolefine comprising ether groups, etc..
• polymers having oxygen containing groups attached to the main chain are, e.g., addition polymers comprising moieties derived from esters of unsaturated carboxylic acid (e.g. esters of acrylic acid). It is further preferred that the polymers used for forming the other polymeric moieties (POL) in polysiloxane modified resins, useful in toner particles according to the present invention, have a Tg > 40 °C, more preferably a Tg > 50 °C.
• said other polymeric moieties are derived from amorphous polymers and that the final polysiloxane modified polymer is still an amorphous polymer.
• the resins used to react, according to the present invention, with the epoxy groups of a polysiloxane are more preferably (co)polyesters having a Tg > 40 °C, preferably having a Tg > 50 °C.
• Said (co)polyesters (hereinafter termed polyester) can be produced by any known polycondensation reaction between at least one di- or polycarboxylic acid or its lower alkyl esters and one di- or polyol.
• the polyester, used according to this invention can comprise aromatic dicarboxylic acid moieties.
• aromatic dicarboxylic acid moieties are moieties of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acids, 4,4' diphenylene dicarboxylic acid, 4,4'diphenylether dicarboxylic acid, 4,4' diphenylmethane dicarboxylic acid, 4,4' diphenylsulphodicarboxylic acid, 5-sulphoisophthalic acid, etc and mixtures of these acid moieties.
• the polyester used according to the present invention, can also comprise aliphatic dicarboxylic acid moieties. It may comprise saturated aliphatic dicarboxylic acid moieties derived from, e.g., succinic acid, glutaric acid, adipic acid, sebacic acid, etc and/or unsaturated aliphatic carboxylic acid moieties derived from, e.g., maleic acid, fumaric acid, etc.
• the polyester can be linear or branched.
• polycarboxylic acids as, e.g. trimellitic acid, trimesinic acid, pyromelitic acid, etc. or polyhydroxy compounds, as, e.g., trimethylolpropane, glycerol, pentaerythritol, etc. can be used.
• diols used to condensate with the di-or polycarboxylic acids can be either aliphatic or aromatic.
• alkylene diol moieties are moieties of ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,5-pentanediol, neopentylglycol, 1,4-cyclohexanedimethanol.
• Aromatic diols useful in a polyester to be used according to this invention are hydroquinone, bisfenol A, ethoxylated bisfenol A, propoxylated bisphenol A, p-xylene glycol, etc.
• mixtures of aliphatic and aromatic diols can be used in a polyester for use according to the present invention.
• Polyester derivatives (modified by other moieties than polysiloxane moieties) can be used to produce the polysiloxane modified resins according to the present invention.
• Such polyester are disclosed in WO 93/20129 and can also successfully be used to produce a polysiloxane modified resin according to the present invention.
• polyester derivatives When using polyester derivatives, to produce the polysiloxane modified resins according to the present invention, also polyesters that carry in the side-chain(s) crystalline polymers may be used. Such polyester derivatives have been described in European Application 94203323.4 filed on November 15, 1994, which is incorporated herein by reference.
• vinyl type addition polymers having a Tg > 40 °C and possessing in their structure said acidic and/or hydroxyl groups introduced by (random) copolymerization or graft-copolymerization, e.g. copolymers of lower alkyl esters of acrylic acid and/or styrene with unsaturated acids such as acrylic acid, methacrylic acid, maleic acid and itaconic acid or with hydroxyethylmethacrylate.
• addition polymers comprising terminal free carboxylic acid groups are very useful polymers for the preparation of polysiloxane modified resins according to the present invention.
• the (co)polymers useful, according to the present invention, for the reaction with the epoxy groups comprised in the polysiloxane are preferably (co)polymers having an acid value (AV) and/or an hydroxyl value (HV) between 2 and 50 mg KOH per g of polymer, more preferably between 5 and 40 mg KOH per g of (co)polymer.
• AV acid value
• HV hydroxyl value
• polysiloxane modified resins both polycondensation copolymers and addition polymers, useful in toner particles according to the present invention, could proceed at reaction temperatures of at most 200 °C (thus diminishing the risks of decomposition of the polysiloxane), when polysiloxane modified resins are made wherein the polysiloxane (PS) is attached to the other moieties (POL) of said modified resins over an ether group or an ester group.
• polysiloxane modified resin means block copolymers as well as graft copolymers as well as cross-linked copolymers.
• reaction of epoxy terminated polysiloxane derivatives with (co)polymers comprising carboxyl and/or hydroxyl groups, preferably with (co)polymers comprising carboxyl groups is a simple, well controllable, relatively fast, chemical reaction, needing no organic solvent and not needing complex dosing of reaction ingredients during the reaction period.
• the chemical reaction basically proceeds between the carboxyl and/or hydroxyl groups comprised in the (co)polymer and the epoxy groups terminating the polysiloxane.
• the polysiloxanes, used according to the present invention can be bi-functional, i.e. carrying two terminal epoxy-groups or mono-functional, i.e. carrying only one terminal epoxy group.
• polysiloxane modified resins by the reaction between polysiloxane compounds, comprising an epoxy group and (co)polymers, comprising free carboxylic acid groups (either terminal or in side chains) proceeds at relatively low temperatures and goes to completion after a relatively short reaction time. Typical reaction times are between 30 and 300 minutes at temperatures between 150 and 200 °C. This is especially so when the polysiloxane compounds have a polymerization degree of at most 20. With polysiloxane compounds showing a higher degree of polymerization, the reaction speed is decreased and more time is needed to get the reaction to completion. When the reaction is not completed, the polysiloxane modified resins can easily be purified by a simple extraction of the unreacted polysiloxane compounds in a suitable solvent, e.g. hexane.
• a suitable solvent e.g. hexane.
• a low molecular weight prepolymer is formed by the direct polycondensation of the di- or polycarboxylic acids, the di- or polyols (preferably in this step only dicarboxylic acids and diols are used), optionally a diamine or lactam, and the polysiloxane, carrying at least one epoxy group, present in the reaction mixture.
• the reaction is carried out at elevated temperature (150 to 200 °C), optionally in the presence of proper catalysts, e.g. dibutyltindioxide, dibutyltindilaurate, zincoxide, stannous oxide as are described in EP-A 234 899.
• step (iii) above) the prepolymer is further reacted at a temperature of between 150 and 200 °C, if necessary under vacuum, optionally after the addition of a polyol and/or a polycarboxylic acid, until the desired visco-elasticity is reached (in this step preferably polyols or polycarboxylic acids are used).
• Polysiloxane modified resins are not only useful for incorporation in toner particles, but can also favourably be used in a coated layer on a final substrate, especially a toner receiving layer on a transparent or opaque polymeric support, offering, especially in hot-pressure fixing systems, a very low adhesion to the hot-fixing roller.
• Said coated layer can be used to receive toner particles comprising a polysiloxane modified resin, according to the present invention, as toner resin as well as toner particles comprising other toner resins.
• Polysiloxane modified resins can also favourably be used in a topcoat (outermost layer) on a final image present on a sheet or web material wherein the image can be made by any imaging means, e.g., electro(stato)graphic means, photographic means, printing means, etc..
• a polysiloxane modified resin as defined in the present invention can be applied by depositing a colourless toner composition comprising said polysiloxane modified resin or by coating a solution, comprising said polysiloxane modified resin, on top of said image (both on monochrome and multicolor images). This makes it possible to have a final print exhibiting high abhesive characteristics, which when the final image is conserved in e.g. plastic folders, is a desirable feature.
• Polysiloxane modified resins as defined in the present invention can also be used to form a protective coating on sheet or web materials either alone or in admixture with other polymers.
• Polysiloxane modified resins as defined in the present invention, can also favourably be used as ingredient in protective layers coated on X-ray intensifying screens and storage phosphor screens.
• Said polysiloxane modified resins are also very useful in thermosublimation transfer imaging materials, both in the dye donor sheet and in the acceptor sheet, due to the abhesive properties of said resins.
• the water repellency of said polysiloxane modified resins can be adjusted by changing the amount of polysiloxane moieties that are incorporated in the resin. It is preferred to add at least 5 % by weight of polysiloxane moieties, preferably more than 7.5 % by weight.
• the glass transition temperature (Tg) mentioned in the examples was determined according to ASTM Designation : D 3418-82.
• the Tg mentioned in the examples is the Tg of the non-polysiloxane moieties (the other polymeric moieties, POL) of the polysiloxane modified resin.
• the percentage of polysiloxane incorporated in the polysiloxane modified resin was determined gravimetrically. 5 g of the polysiloxane modified resin were crushed to a powder having particle sizes between 250 and 750 ⁇ m and stirred for 24 hours at room temperature in 50 ml hexane. The free polysiloxane was dissolved in the hexane and the polysiloxane modified resin not. After filtration, washing with hexane and drying, the weight of the undissolved powder of the polysiloxane modified resin was determined. From the difference in weight of the undissolved powder and the weight of the powder before the hexane treatment the % by weight of the incorporated polysiloxane was determined.
• ATLAC T500 which is a trade name of Atlas Chemical Industries Inc. Wilmington, Del. U.S.A. for a linear polyester of fumaric acid and propoxylated bisphenol A, having a Tg of about 55 °C, and an acid value of 17 mg KOH/g polyester
• TEGOMER E-Si-2130 tradename of Th. Goldschmid AG, Essen, Germany
• X' is This mixture was molten in a glass reaction vessel under N 2 atmosphere and with nitrogen bubbling through the reaction mixture. The mixture was heated to 200 °C. After 60 minutes the reaction was stopped and the polysiloxane modified resin was recovered. The cooled mass was crushed and the properties of the polysiloxane modified resin were determined. These properties are reported in table 2.
• Different polysiloxane modified resins were prepared according to synthesis example 1, but with different contents of polysiloxane compounds (the amounts of polysiloxane added are reported in table 3), under reduced pressure and with mechanical stirring.
• the resins were dissolved in methyl-ethylketone and coated on an unsubbed polyethyleneterephthalate support (PET) of 100 ⁇ m thickness by means of a bar coating machine.
• PET polyethyleneterephthalate support
• the dry layers were 10 ⁇ m thick.
• a layer of non modified linear polyester (ATLAC 500, trade name) was coated.
• the coatings were attached to a tiltable table, a drop of water was applied to each of the coatings.
• the tiltable table was gradually tilted and the angle under which the drop started to flow was measured (tilt angle).
• All three developers were made by mixing 5 % of toner particles with coated ferrite carrier particles having an average volume diameter of 60 ⁇ m and a magnetization of 60 emu/g.
• the toner particles were used as such, i.e. without the addition of any flow improving additive.
• the three developers were used to develop an image on a reflecting support in a configuration where NO cleaning potential was applied to the photoconductive member.
• the images were fused for 10 minutes at 120 °C.

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• 1996
  • 1996-03-18 EP EP96200738A patent/EP0740217A1/fr not_active Withdrawn

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