EP0064204B1 - Production of carbonless copying papers by flexography - Google Patents

Production of carbonless copying papers by flexography Download PDF

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Publication number
EP0064204B1
EP0064204B1 EP82103255A EP82103255A EP0064204B1 EP 0064204 B1 EP0064204 B1 EP 0064204B1 EP 82103255 A EP82103255 A EP 82103255A EP 82103255 A EP82103255 A EP 82103255A EP 0064204 B1 EP0064204 B1 EP 0064204B1
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EP
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Prior art keywords
microcapsules
printing
production
diisocyanate
solvents
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EP82103255A
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German (de)
French (fr)
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EP0064204A1 (en
Inventor
Ulrich Dr. Nehen
Manfred Dr. Dahm
Artur Dr. Haus
Gert Dr. Jabs
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Bayer AG
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Bayer AG
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/124—Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components
    • B41M5/132—Chemical colour-forming components; Additives or binders therefor

Definitions

  • Reaction copy papers are known (see M. Gutcho, Capsule Technology and Microencapsulation, Noyes Data Corporation, 1972, pages 242-277; G. Baxter in Microencapsulation, Processes and Applications, edited by JE Vandegaer, Plenum Press, New York, London, pages 127-143 They preferably consist of two or more sheets of paper laid loosely on top of one another, the upper one on the back side containing a donor layer and the lower one on the front side containing a receiver layer, ie a donor layer and a receiver layer are in contact with each other contains microcapsules, the core material of which is a solution of a color former in an organic solvent, and the receiver layer contains a material that develops the dye former into a dye. When writing, the capsules are destroyed under the pressure of the writing instrument, and the leaking core material hits the receiver layer, so that a copy is made t.
  • the receiver layer usually contains binders and pigments, e.g. active absorbents such as kaolin, attapulgite, montmorillonite, bentonite, acidic bleaching earth or phenolic resins. You can e.g. Use acid-activated dyes on the donor layer and acid-reacting components in the receiver layer.
  • active absorbents such as kaolin, attapulgite, montmorillonite, bentonite, acidic bleaching earth or phenolic resins.
  • reaction copy papers A further development of these reaction copy papers are the "one-component" reaction copy papers.
  • one side of a single sheet of paper carries the color precursor, generally in the form of microcapsules, and at the same time the color developer. If pressure is now applied, e.g. using a typewriter or other writing tool, the capsule containing the color precursor is torn open and the color precursor reacts with the color developer surrounding it (see US Pat. No. 2,730,456).
  • the paper substrates are generally used to manufacture these carbon-free copy systems. Fully coated in a known manner with an aqueous coating composition, as described in German Offenlegungsschriften 1 934 457 and 1 955 542. After that, the water must be evaporated, which requires a considerable amount of energy and complex and costly equipment.
  • microcapsules containing dye precursors from e.g. Have polyurethanes are suspended in solvents such as benzene, chlorobenzene, trichlorodiphenyl, trichlorethylene and hexane, which can contain a small amount of polystyrene dissolved in chlorobenzene (Examples 3 and 8).
  • solvents such as benzene, chlorobenzene, trichlorodiphenyl, trichlorethylene and hexane, which can contain a small amount of polystyrene dissolved in chlorobenzene (Examples 3 and 8).
  • a flexographic printing process is also not mentioned in US Pat. No. 3,432,327.
  • DE-A-25 41 001 describes a process in which aqueous or solvent-containing microcapsule dispersions are printed without the use of binders. As a result, after drying, the microcapsules are not sufficiently bonded to the paper, so that they are blurred or removed when the paper is used, thereby losing the write-through effect of the paper.
  • the invention relates to a process for the production of pressure-sensitive, carbon-free carbonless papers by means of flexographic printing, which is characterized in that a preparation containing optionally chlorinated hydrocarbons or ethers which are liquid at 20 ° C. and has a boiling point of 50-180 ° C. as Solvent, a content of polymeric binders soluble in these solvents, and a content of dye precursor-containing microcapsules with an average diameter of 5-20 11 m partially or over the whole area using the technique of flexographic printing using a printing form which does not swell in the solvents of the preparation, is printed on paper and then the solvent is removed.
  • a preparation containing optionally chlorinated hydrocarbons or ethers which are liquid at 20 ° C. and has a boiling point of 50-180 ° C. as Solvent, a content of polymeric binders soluble in these solvents, and a content of dye precursor-containing microcapsules with an average diameter of 5-20 11 m partially or over the whole area
  • the preparation preferably contains 2 to 30 parts by weight of the polymeric binder - in particular cyclo rubber, polyamides, copolymers of styrene with alkyl (meth) acrylates, certain soluble polyurethanes or mixtures thereof, 2 to 30 parts by weight of microcapsules, preferably those whose walls are made of Polyurethanes, polyurethane-polyurea or polycarbodiimide consist and 96 to 40 parts by weight of the solvent.
  • spacers (2 to 20 parts by weight per 100 parts by weight of preparation) and further auxiliaries and additives (up to 50 parts by weight per part by weight of preparation) can be present.
  • microcapsules to be used according to the invention A large number of the microcapsules to be used according to the invention and processes for their production are known.
  • microcapsules can be used which are made of gelatin and gum arabic by coacervation or complex coacervation, as well as gelatin and other inorganic and organic polyanions have been produced. Appropriate methods are described in M. Gutcho, Capsule Technology and Microencapsulation, Noyes Data Corporation 1972.
  • microcapsules are used, the walls of which consist of polymers, polycondensation and polyaddition products.
  • Microcapsules with walls made of special poly (meth) acrylates e.g. described in DE-OS 237 545, 2119 933 and 2 920 846 can be used.
  • phenol or urea-formaldehyde condensates can be used as wall material, optionally also in combination with the capsule wall polymers mentioned above.
  • Microcapsules are preferably used in the process according to the invention, the shells of which consist of polyadducts of polyisocyanates and polyamines.
  • Isocyanates to be used for the production of such microcapsules are diisocyanates such as xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2- diisocyanate, butyten-1,2-diisocyanate, ethylidene diisocyanate, cyclo-hexyl-1,2-diisocyanate, cyclohexyl-1,4-diisocyanate, polyisocyanate prepolymers, for example adduct of hexamethylene diisocyanate and hexanetriol, adduct of 2,4-tolylene diisocyanate with pyrocatechol, addition product of tolylene diisocyanate with hexanetriol, addition product of tolylene diisocyanate with trimethylolpropane or suitable polyisocyanates which
  • modified aliphatic isocyanates are those based on hexamethylene-1,6-diisocyanate, m-xylylene diisocyanate, 4,4'-diisocyanatodicyclohexylmethane or isophorone diisocyanate, which have at least two functional isocyanate groups per molecule.
  • Suitable compounds are polyisocyanates based on derivatives of hexamethylene-1,6-diisocyanate with a biuret structure, the production of which is evident from DE-AS 1 101 304 and 1 543178, and from DE-OS 1 568 017 and 1 931 055.
  • the polyisocyanates that can be used can additionally be modified before use for microencapsulation by reaction with di- and trifunctional alcohols such as ethanediol, glycerol or trimethylolpropane or carboxylic acids such as succinic acid, adipic acid, sebacic acid in proportions of 0.01 to 0.5 mol per isocyanate equivalent .
  • di- and trifunctional alcohols such as ethanediol, glycerol or trimethylolpropane
  • carboxylic acids such as succinic acid, adipic acid, sebacic acid in proportions of 0.01 to 0.5 mol per isocyanate equivalent .
  • carbodiimide, uretdione, uretonimine, uretidinedione diimine, 4-imino-oxazolidinone (2), ⁇ -alkylene-propiolactone or cyclobutanedione (1, 3) groups can also be present as reactive groups .
  • polyisocyanato-polyuretonimines can be used, such as those produced by carbodiimidization of hexamethylene-1,6-diisocyanate containing biuret groups with organic phosphorus catalysts, by further reaction of primarily formed carbodiimide groups with isocyanate groups to form uretonimine groups.
  • isocyanates can be used in a mixture with one another and other aliphatic and aromatic isocyanates.
  • the resulting modified polyisocyanate can contain considerable proportions of oxadiazinetrione, triisocyanurate or sym. Triazinedioneimine as a structural element. Such products are also suitable as shell formers.
  • Examples of the encapsulated color formers are triphenylmethane compounds, diphenylmethane compounds, xanthene compounds, thiazine compounds and spiropyran compounds.
  • diphenylmethane compounds are 4,4'-bis-dimethylaminobenzhydrylbenzylether, N-halophenylleucolamine, N-ß-naphthylleucolamine, N-2,4,5-trichlorophenylleucolamine and N-2,4-dichlorophenolleucolamine.
  • xanthene compounds are rhodamine- ⁇ -anilinolactam, rhodamine- ⁇ - (p-nitroaniline) lactam, rhodamine- ⁇ - (p-chloroaniline) lactam, 7-dimethylamine-2-methoxifluorane, 7-diethylamine-3- methoxifluorane, 7-diethylamine-3-methyl-fluorane, 7-diethylamine-3-chlorofluorane, 7-diethylamine-3-chloro-2-methylfluorane, 7-diethylamine-2,4-dimethylfluorane, 7-diethylamine-2,3- dimethylfluorane, 7-diethylamine- (3-acetyl-methylamine) -fluorane, 7-diethylamine-3- (dibenzylamine) -fluoro-ran, 7-diethylamine-3- (methylbenzylamine
  • thiazine compounds are N-benzoyl-leucomethylene blue, o-chlorobenzoylleucomethylene blue, p-nitrolbenzoylleucomethylene blue.
  • spiro compounds are 3-methyl-2,2'-spirobis (benzo (f) chromium), 3-ethyl-spirodinaphthopyran.
  • Solvents that dissolve these color formers are e.g. chlorinated diphenyl, chlorinated paraffin, cottonseed oil, peanut oil, silicone oil, phthalate ester, phosphate ester, sulfonate ester, monochlorobenzene, furthermore partially hydrogenated terphecyle, alkylated naphthalenes, aryl ethers, aryl alkyl ethers, higher alkylated benzene and others which can be used alone or in combination.
  • Diluents are often added to the solvents, e.g. Kerosene, n-paraffins, isoparaffins.
  • the colorants and the isocyanate are first dissolved in the solvents mentioned and this organic phase is emulsified in the continuous aqueous phase, which may contain protective colloid and, if appropriate, emulsifiers.
  • An aqueous polyamine solution is added to the emulsion in a stoichiometric amount to the polyisocyanate in the organic phase.
  • Protective colloids and emulsifying aids are added to the aqueous phase to emulsify and stabilize the emulsion formed.
  • Examples of such products acting as protective colloids are carboxymethyl cellulose, gelatin and polyvinyl alcohol.
  • emulsifiers are ethoxylated 3-benzyl-hydroxibiphenyl, reaction products of nonylphenol with different amounts of ethylene oxide and sorbitan fatty acid ester.
  • the microcapsules can be produced continuously or batchwise. Dispersing devices which generate a shear gradient are generally used. Examples include blade, basket, high-speed stirrers, colloid mills, homogenizers, ultrasonic dispersers, nozzles, steel nozzles, and Supraton machines.
  • the strength of the turbulence during mixing is primarily decisive for the diameter of the microcapsules obtained. Capsules from 1 to 2000 ⁇ m in size can be made. Capsules with diameters of 2 to 20 ⁇ m are preferred.
  • the capsules do not agglomerate and have a narrow particle size distribution.
  • the weight ratio of core material to shell material is 50 to 90 to 50 to 10.
  • microcapsules are generally obtained as an aqueous suspension. You can e.g. isolate the microcapsules as agglomerate-free powder by spray drying.
  • the components - microcapsule powder, solvent and binder - can be mixed in conventional mixing units.
  • the binder dissolves in the solvent and the microcapsules are distributed homogeneously in this mixture. It is surprising that a stable and uniform distribution of the microcapsules can be achieved in this way, since the non-polar solvents and the polar microcapsules are inherently incompatible.
  • the solvent and the binder can also be introduced into the aqueous suspension of the microcapsules and the water can then be drawn off in a vacuum (flushing process).
  • the solvent may already contain one or more components of the printing ink.
  • the amount of microcapsules that is incorporated into the formulation depends on the requirements that must be placed on the finished printing ink.
  • the amount of capsules is set according to the method of the invention as high as is reasonable considering the rheology of the finished printing ink, in order to apply an optimal amount of microcapsules with the lowest possible coating weight.
  • the flexographic printing inks can normally be produced with simple stirrers, high-speed stirrers and / or high-performance stirrers.
  • the incorporation of the individual components of the printing inks can be carried out in any order.
  • binders can be used according to the method according to the invention, which binders are used according to the known prior art for producing a printing ink which can be processed in flexographic printing.
  • binders are used according to the known prior art for producing a printing ink which can be processed in flexographic printing.
  • Suitable solvents or solvent mixtures are aromatic and aliphatic hydrocarbons, halogenated aromatic and aliphatic hydrocarbons and ethers. They are liquid at 20 ° C and have boiling points between 50 and 180 ° C.
  • Examples include white spirit, white spirit, special gasoline, n-pentane, n-hexane, cyclohexane, ligroin, petroleum ether, light petrol, carbon tetrachloride, perchlorethylene, cumene, chlorobenzene, methyl tert-butyl ether, tert-amyl methyl ether.
  • Suitable materials are isoprene rubber, acrylonitrile-butadiene rubber, and ethylene-propylene-diene rubber.
  • dispersing aids preferably from the group of the cationic surfactants, can be added to the printing ink.
  • spacers are added to the printing ink in amounts of 2-20% by weight.
  • these spacers are also used in the production of the usual carbonless carbonless papers.
  • they can consist of cellulose fiber particles or starch granules, the diameter of which is usually 1.5 to 5 times the microcapsule diameter.
  • Pigments and auxiliaries which have a favorable effect on the opacity of the coating can be added as further additives.
  • drying retarders When using slow-running printing presses, oversized plate cylinders or particularly strongly absorbent "print carriers”, drying retarders can also be used. Fast dryers and accelerators are used when extremely high printing speeds are to be achieved.
  • a 30% aqueous microcapsule dispersion was prepared, the microcapsule walls of which consisted of a polyaddition product of the oxadiazinetrione of hexamethylene diisocyanate and a polyamine.
  • the capsule contents were a solution of 2.7% crystal violet lactone and 0.9% N-benzoyl leukomethylene blue in diisopropyl diphenyl.
  • the core / wall ratio of the microcapsules was 83:17.
  • the 30% capsule dispersion was converted into a largely agglomerate-free capsule powder by spray drying, the mean capsule diameter of which was determined to be 7.3 ⁇ m.
  • the printing ink produced in this way containing 12% by weight of microcapsules, was printed on the back of a commercially available CF paper (Jeset-CF from Feldmühle) in the form of a square of 12 cm edge length using a flexographic printing machine.
  • the application weight of the coating was up to 2.6 g / m 2 after drying, which corresponded to an amount of capsules of approximately 1.6 g / m 2 .

Description

Reaktionsdurchschreibepapiere sind bekannt (vergl. M. Gutcho, Capsule Technology and Microencapsulation, Noyes Data Corporation, 1972, Seiten 242-277; G. Baxter in Microencapsulation, Processes and Applications, herausgegeben von J.E. Vandegaer, Plenum Press, New York, London, Seiten 127-143. Sie bestehen vorzugsweise aus zwei oder mehreren lose aufeinandergelegten Papierblättern, wobei das jeweils obere auf der Rückseite eine Geberschicht und das jeweils untere auf der Vorderseite eine Nehmerschicht enthält. Es ist also jeweils eine Geberschicht und eine Nehmerschicht miteinander in Kontakt. Die Geberschicht enthält Mikrokapseln, deren Kernmaterial eine Lösung eines Farbbildners in einem organischen Lösungsmittel ist, und die Nehmerschicht enthält ein Material, das den Farbstoffbildner zum Farbstoff entwickelt. Beim Beschreiben werden die Kapseln unter dem Druck des Schreibgerätes zerstört, und das auslaufende Kernmaterial trifft auf die Nehmerschicht, so daß eine Durchschrift entsteht.Reaction copy papers are known (see M. Gutcho, Capsule Technology and Microencapsulation, Noyes Data Corporation, 1972, pages 242-277; G. Baxter in Microencapsulation, Processes and Applications, edited by JE Vandegaer, Plenum Press, New York, London, pages 127-143 They preferably consist of two or more sheets of paper laid loosely on top of one another, the upper one on the back side containing a donor layer and the lower one on the front side containing a receiver layer, ie a donor layer and a receiver layer are in contact with each other contains microcapsules, the core material of which is a solution of a color former in an organic solvent, and the receiver layer contains a material that develops the dye former into a dye. When writing, the capsules are destroyed under the pressure of the writing instrument, and the leaking core material hits the receiver layer, so that a copy is made t.

Die Nehmerschicht enthält in der Regel Bindemittel und Pigmente, z.B. aktive Absorbentien, wie Kaolin, Attapulgit, Montmorillonit, Bentonit, saure Bleicherde oder Phenolharze. Man kann z.B. auf der Geberschicht säureaktivierbare Farbstoffe und in der Nehmerschicht sauer reagierende Komponenten einsetzen.The receiver layer usually contains binders and pigments, e.g. active absorbents such as kaolin, attapulgite, montmorillonite, bentonite, acidic bleaching earth or phenolic resins. You can e.g. Use acid-activated dyes on the donor layer and acid-reacting components in the receiver layer.

Eine Fortentwicklung dieser Reaktionsdurchschreibepapiere sind die "Einkomponenten"-Reaktionsdurchschreibepapiere. In diesen trägt eine Seite eines einzelnen Papierblattes den Farbvorläufer, im allgemeinen in Form von Mikrokapseln und gleichzeitig den Farbentwickler. Wenn nun Druck ausgeübt wird, z.B. durch eine Schreibmaschine oder ein anderes Schreibwerkzeug, wird die den Farbvorläufer enthaltende Kapsel aufgerissen, und der Farbvorläufer reagiert mit dem ihn umgebenden Farbentwickler (vergl. US-PS 2 730 456).A further development of these reaction copy papers are the "one-component" reaction copy papers. In these, one side of a single sheet of paper carries the color precursor, generally in the form of microcapsules, and at the same time the color developer. If pressure is now applied, e.g. using a typewriter or other writing tool, the capsule containing the color precursor is torn open and the color precursor reacts with the color developer surrounding it (see US Pat. No. 2,730,456).

Die Papiersubstrate werden zur Herstellung dieser kohlefreien Durchschreibesysteme i.a. in bekannter Weise vollflächig mit einer wäßrigen Beschichtungskomposition beschichtet, wie in den deutschen Offenlegungsschriften 1 934 457 und 1 955 542 beschrieben. Danach muß das Wasser verdampft werden, was einen beträchtlichen Aufwand an Energie und eine komplexe und kostspielige Apparatur erfordert.The paper substrates are generally used to manufacture these carbon-free copy systems. fully coated in a known manner with an aqueous coating composition, as described in German Offenlegungsschriften 1 934 457 and 1 955 542. After that, the water must be evaporated, which requires a considerable amount of energy and complex and costly equipment.

Vollflächige Beschichtungen sind unrationell, weil in den meisten Fällen nur Teile des Durchschreibepapiers ausgenutzt werden.Full-surface coatings are inefficient because in most cases only parts of the carbonless paper are used.

Es sind zahlreiche Verfahren bekannt, Beschichtungsmassen partiell auf ein Trägermaterial aufzubringen. In den US-Patentschriften 3 016 308, Beispiel IX und 3 914 511, sowie in der DE-AS 19 06 823, den DE-OS 2541 001 und 2 833 651 wird beschrieben, daß man wäßrige Dispersionen von Mikrokapseln mit Hilfe verschiedener Drucktechniken partiell auf einen Papierträger aufdrucken kann. Durch den Kontakt mit Wasser kann es auf dem Papier zu Verwerfungen kommen, wodurch eine gleichmäßige Trocknung und ein präziser Druck, insbesondere von Durchschreibeformularen, mindestens sehr erschwert wird. Hinzukommt, daß das Verdampfen von Wasser einen beträchtlichen Energieaufwand erfordert.Numerous methods are known for partially applying coating compositions to a carrier material. US Pat. Nos. 3,016,308, Example IX and 3,914,511, and DE-AS 19 06 823, DE-OS 2541 001 and 2,833,651 describe that aqueous dispersions of microcapsules are partially processed using various printing techniques can print on a paper backing. Contact with water can lead to warping on the paper, making uniform drying and precise printing, especially of carbonless forms, at least very difficult. In addition, the evaporation of water requires a considerable amount of energy.

Aus der US-A-3 016 308 ist nun eine wasserfreie Zubereitung zur Herstellung von druckempfindlichen, kohlenfreien Durchschreibepapieren bekannt, die einen Gehalt an Benzol (Beispiel VIII), Petroleum (Beispiel XIV) oder Toluol (Tabel 2), einen Gehalt an in diesen Lösungsmitteln lösliche polymeren Bindemitteln (Isobutylmethacrylat (Beispiel VIII), Cyclokautschuk (Beispiel XIV) oder Methylmethacrylat (Tabel 2)) und einen , Gehalt an Farbstoffvorläufer enthaltenden Mikrokapseln eines mittleren Durchmessers von 0,5 - 10 µm (Beispiel VIII) oder 1 - 60 µm (Beispiel XIV) aufweisen. Ein Flexodruckverfahren wird in der US-A-3 016 308 nicht erwähnt.From US-A-3 016 308 an anhydrous preparation for the production of pressure-sensitive, carbon-free carbonless papers is now known, which contains benzene (example VIII), petroleum (example XIV) or toluene (table 2), a content of these Solvent-soluble polymeric binders (isobutyl methacrylate (Example VIII), cyclo rubber (Example XIV) or methyl methacrylate (Table 2)) and a content of microcapsules containing dye precursors of an average diameter of 0.5-10 µm (Example VIII) or 1-60 µm (Example XIV). A flexographic printing process is not mentioned in US-A-3 016 308.

Außerdem sind aus der US-A-3 432 327 Zubereitungen bekannt, die einen Gehalt an Farbstoffvorläufer enthaltenden Mikrokapseln aus z.B. Polyurethanen aufweisen. Die Mikrokapseln sind suspendiert in Lösungsmitteln, wie Benzol, Chlorbenzol, Trichlordiphenyl, Trichlorethylen und Hexan, die eine kleine Menge Polystyrol gelöst in Chlorbenzol (Beispiel 3 und 8) enthalten können. Auch in der US-A-3 432 327 wird ein Flexodruckverfahren nicht erwähnt.Also known from US-A-3,432,327 are preparations which contain microcapsules containing dye precursors from e.g. Have polyurethanes. The microcapsules are suspended in solvents such as benzene, chlorobenzene, trichlorodiphenyl, trichlorethylene and hexane, which can contain a small amount of polystyrene dissolved in chlorobenzene (Examples 3 and 8). A flexographic printing process is also not mentioned in US Pat. No. 3,432,327.

In der DE-A-25 41 001 wird ein Verfahren beschrieben, bei dem wäßrige oder lösungsmittelhaltige Mikrokapseldispersionen ohne Verwendung von Bindemitteln verdruckt werden. Das hat zur Folge, daß nach dem Trocknen die Mikrokapseln nicht genügend mit dem Papier verbunden sind, so daß sie beim Gebrauch des Papiers verwischt oder entfernt werden, wodurch die Durchschreibewirkung des Papiers verlorengeht.DE-A-25 41 001 describes a process in which aqueous or solvent-containing microcapsule dispersions are printed without the use of binders. As a result, after drying, the microcapsules are not sufficiently bonded to the paper, so that they are blurred or removed when the paper is used, thereby losing the write-through effect of the paper.

Gegenstand der Erfindung ist ein Verfahren zur Herstellung von druckempfindlichen, kohlefreien Durchschreibepapieren mittels Flexodruck, das dadurch gekennzeichnet ist, daß man eine Zubereitung mit einem Gehalt an gegebenenfalls chlorierten, bei 20° C flüssigen Kohlenwasserstoffen oder Ethern mit einem Siedepunkt von 50 - 180°C als Lösungsmittel, einem Gehalt an in diesen Lösungsmitteln löslichen polymeren Bindemitteln, und einem Gehalt an Farbstoffvorläufer enthaltenden Mikrokapseln eines mittleren Durchmessers von 5 - 20 11m partiell oder vollflächig mit der Technik des Flexodrucks unter Benutzung einer in den Lösungsmitteln der Zubereitung nicht quellenden Druckform auf Papier aufdruckt und anschließend das Lösungsmittel entfernt.The invention relates to a process for the production of pressure-sensitive, carbon-free carbonless papers by means of flexographic printing, which is characterized in that a preparation containing optionally chlorinated hydrocarbons or ethers which are liquid at 20 ° C. and has a boiling point of 50-180 ° C. as Solvent, a content of polymeric binders soluble in these solvents, and a content of dye precursor-containing microcapsules with an average diameter of 5-20 11 m partially or over the whole area using the technique of flexographic printing using a printing form which does not swell in the solvents of the preparation, is printed on paper and then the solvent is removed.

Bevorzugt enthält die Zubereitung 2 bis 30 Gew.-Teile des polymeren Bindemittels - insbesondere Cyclokautschuk, Polyamide, Copolymerisate von Styrol mit Alkyl(meth)acrylaten, bestimmten löslichen Polyurethanen oder Mischungen daraus, 2 bis 30 Gew.-Teile Mikrokapselnbevorzugt solchen, deren Wände aus Polyurethanen, Polyurethan-Polyharnstoff oder Polycarbodiimid bestehenund 96 bis 40 Gew. Teile des Lösungsmittels.The preparation preferably contains 2 to 30 parts by weight of the polymeric binder - in particular cyclo rubber, polyamides, copolymers of styrene with alkyl (meth) acrylates, certain soluble polyurethanes or mixtures thereof, 2 to 30 parts by weight of microcapsules, preferably those whose walls are made of Polyurethanes, polyurethane-polyurea or polycarbodiimide consist and 96 to 40 parts by weight of the solvent.

Zusätzlich können "Abstandshalter" (2 bis 20 Gew.-Teile pro 100 Gew.-Teile Zubereitung) und weitere Hilfs-und Zusatzstoffe (bis zu 50 Gew.-Teile pro Gew.-Teil Zubereitung) vorhanden sein.In addition, "spacers" (2 to 20 parts by weight per 100 parts by weight of preparation) and further auxiliaries and additives (up to 50 parts by weight per part by weight of preparation) can be present.

Die erfindungsgemäß einzusetzenden Mikrokapseln und Verfahren zu deren Herstellung sind in großer Zahl bekannt. So können Mikrokapseln verwendet werden, die durch Koazervierung oder Komplexkoazervierung aus Gelatine und Gummi arabicum, sowie Gelatine und anderen anorganischen und organischen Polyanionen hergestellt worden sind. Entsprechende Verfahren sind in M. Gutcho, Capsule Technology and Microencapsulation, Noyes Data Corporation 1972, beschrieben.A large number of the microcapsules to be used according to the invention and processes for their production are known. For example, microcapsules can be used which are made of gelatin and gum arabic by coacervation or complex coacervation, as well as gelatin and other inorganic and organic polyanions have been produced. Appropriate methods are described in M. Gutcho, Capsule Technology and Microencapsulation, Noyes Data Corporation 1972.

Insbesondere werden Mikrokapseln verwendet, deren Wände aus Polymeren, Polykondensations- und Polyadditionsprodukten bestehen.In particular, microcapsules are used, the walls of which consist of polymers, polycondensation and polyaddition products.

Die nachfolgende Übersicht ist G. Baxter, Microencapsulation, Processes and Applications, herausgegeben von J.E. Vandegaer, entnommen und zeigt eine Zusammenstellung der heute verwendeten Kapselwandpolymeren.

Figure imgb0001
The following overview is taken from G. Baxter, Microencapsulation, Processes and Applications, edited by JE Vandegaer, and shows a compilation of the capsule wall polymers used today.
Figure imgb0001

Es können auch Mikrokapseln mit Wänden aus speziellen Poly(meth)acrylaten, wie z.B. in den DE-OS 237 545, 2119 933 und 2 920 846 beschrieben, verwendet werden.Microcapsules with walls made of special poly (meth) acrylates, e.g. described in DE-OS 237 545, 2119 933 and 2 920 846 can be used.

Ferner können Phenol- oder Harnstoff-Formaldehydkondensate als Wandmaterial eingesetzt werden, gegebenenfalls auch in Kombination mit den vorgenannten Kapselwandpolymeren.Furthermore, phenol or urea-formaldehyde condensates can be used as wall material, optionally also in combination with the capsule wall polymers mentioned above.

Bevorzugt werden beim erfindungsgemäßen Verfahren Mikrokapseln verwendet, deren Hüllen aus Polyadditionsprodukten aus Poly-Isocyanaten und Polyaminen bestehen.Microcapsules are preferably used in the process according to the invention, the shells of which consist of polyadducts of polyisocyanates and polyamines.

Zur Herstellung derartiger Mikrokapseln einzusetzende Isocyanate sind Diisocyanate, wie Xylylen-1,4-diisocyanat, Xylylen-1,3-diisocyanat, Trimethylen-diisocyanat, Hexamethylen-diisocyanat, Propylen-1,2-diisocyanat, Butyten-1,2-diisocyanat, Ethyliden-diisocyanat, Cyclo-hexyl-1,2-diisocyanat, Cyclohexyl-1,4-diisocyanat, Polyisocyanatvorpolymerisate, z.B. Anlagerungsprodukt von Hexamethylendiisocyanat und Hexantriol, Anlagerungsprodukt von 2,4-Toluylen-diisocyanat mit Brenzkatechin, Anlagerungsprodukt von Toluylendiisocyanat mit Hexantriol, Anlagerungsprodukt von Toluylendiisocyanat mit Trimethylolpropan oder geeignete Polyisocyanate, die den vorstehend angegebenen verbindungen analog sind.Isocyanates to be used for the production of such microcapsules are diisocyanates such as xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2- diisocyanate, butyten-1,2-diisocyanate, ethylidene diisocyanate, cyclo-hexyl-1,2-diisocyanate, cyclohexyl-1,4-diisocyanate, polyisocyanate prepolymers, for example adduct of hexamethylene diisocyanate and hexanetriol, adduct of 2,4-tolylene diisocyanate with pyrocatechol, addition product of tolylene diisocyanate with hexanetriol, addition product of tolylene diisocyanate with trimethylolpropane or suitable polyisocyanates which are analogous to the compounds given above.

Weitere modifizierte aliphatische Isocyanate sind solche auf Basis von Hexamethylen-1,6-diisocyanat, m-Xylylen-diisocyanat, 4,4'-Diisocyanato-dicyclohexyl-methan bzw. lsophoron-diisocyanat, die pro Molekül mindestens zwei funktionelle Isocyanatgruppen besitzen.Other modified aliphatic isocyanates are those based on hexamethylene-1,6-diisocyanate, m-xylylene diisocyanate, 4,4'-diisocyanatodicyclohexylmethane or isophorone diisocyanate, which have at least two functional isocyanate groups per molecule.

Weitere geeignete Verbindungen sind Polyisocyanate auf Grundlage von Derivaten des Hexamethylen-1,6-diisocyanats mit Biuretstruktur, deren Herstellung aus den DE-AS 1 101 304 und 1 543178, sowie aus den DE-OS 1 568 017 und 1 931 055 hervorgeht.Other suitable compounds are polyisocyanates based on derivatives of hexamethylene-1,6-diisocyanate with a biuret structure, the production of which is evident from DE-AS 1 101 304 and 1 543178, and from DE-OS 1 568 017 and 1 931 055.

Die verwendbaren Polyisocyanate können vor dem Einsatz zur Mikroverkapselung zusätzlich modifiziert werden durch Umsetzung mit di- und trifunktionellen Alkoholen wie Ethandiol, Glycerin oder Trimethylolpropan bzw. Carbonsäuren wie Bernsteinsäure, Adipinsäure, Sebacinsäure in Anteilen von 0,01 bis 0,5 Mol pro Isocyanat-Äquivalent.The polyisocyanates that can be used can additionally be modified before use for microencapsulation by reaction with di- and trifunctional alcohols such as ethanediol, glycerol or trimethylolpropane or carboxylic acids such as succinic acid, adipic acid, sebacic acid in proportions of 0.01 to 0.5 mol per isocyanate equivalent .

Anstelle der Isocyanatgruppen können als reaktive Gruppen auch Carbodiimid-, Uretdion-, Uretonimin-, Uretidindiondiimin-, 4-Imino-oxazolidinon-(2)-, β-Alkylen-propiolacton- bzw. Cyclobutandion-(1, 3)-gruppen vorhanden sein.Instead of the isocyanate groups, carbodiimide, uretdione, uretonimine, uretidinedione diimine, 4-imino-oxazolidinone (2), β-alkylene-propiolactone or cyclobutanedione (1, 3) groups can also be present as reactive groups .

So sind beispielsweise einsetzbar Polyisocyanato-polyuretonimine, wie sie durch Carbodiimidisierung von Biuretgruppen enthaltendem Hexamethylen-1,6-diisocyanat mit Phosphor-organischen Katalysatoren entatehen, durch weitere Umsetzung primär gebildeter Carbodiimidgruppen mit Isocyanatgruppen zu Uretonimingruppen. Weiterhin können diese Isocyanate in Mischung miteinander und anderen aliphatischen und aromatischen Isocyanaten verwendet werden.For example, polyisocyanato-polyuretonimines can be used, such as those produced by carbodiimidization of hexamethylene-1,6-diisocyanate containing biuret groups with organic phosphorus catalysts, by further reaction of primarily formed carbodiimide groups with isocyanate groups to form uretonimine groups. Furthermore, these isocyanates can be used in a mixture with one another and other aliphatic and aromatic isocyanates.

Je nach Reaktionsbedingungen kann das resultierende modifizierte Polyisocyanat erhebliche Anteile an Oxadiazintrion, Triisocyanurat bzw. sym. Triazindionimin als Strukturelement enthalten. Auch solche Produkte eignen sich als Hüllenbildner.Depending on the reaction conditions, the resulting modified polyisocyanate can contain considerable proportions of oxadiazinetrione, triisocyanurate or sym. Triazinedioneimine as a structural element. Such products are also suitable as shell formers.

Besonders geeignet sind Diisocyanate der Formel 1

Figure imgb0002
n = 3-6.Diisocyanates of the formula 1 are particularly suitable
Figure imgb0002
 n = 3-6.

Zur Umsetzung mit den genanten Isocyanaten geeignete Diamine sind aliphatische primäre oder sekundäre-Di- und Polyamine, wie z.B:

  • Ethylendiamin-(1, 2), Bis(3-aminopropyl)-amin, Hydrazin, Hydrazin-ethanol-(2), Bis-(2-methylaminoethyl)-methylamin, 1,4-Diaminocyclohexan, 3-Amino-1-methyl-amino-propan, N-Hydroxi-ethylethylendiamin, N-Methyl-bis-(3-aminopropyl)-amin, 1,4-Diamino-n-butan, 1,6-Diamino-n-hexan, Ethylen-(1, 2)-diamin-N-Ethylsulfonsäure (als Alkalisalz), N-Amino-ethylethylendiamin-(1,2) (Diethylentriamin) Bis-(N,N'-aminoethyl)-ethylendiamin-(1,2) (Triethylentetramin), Hydrazin und seine Salze werden im vorliegenden Zusammenhang ebenfalls als Diamine angesprochen.
Diamines suitable for reaction with the named isocyanates are aliphatic primary or secondary di- and polyamines, such as:
  • Ethylenediamine (1, 2), bis (3-aminopropyl) amine, hydrazine, hydrazine ethanol (2), bis (2-methylaminoethyl) methylamine, 1,4-diaminocyclohexane, 3-amino-1-methyl -amino-propane, N-hydroxyethylethylene diamine, N-methyl-bis- (3-aminopropyl) -amine, 1,4-diamino-n-butane, 1,6-diamino-n-hexane, ethylene- (1, 2) -Diamine-N-ethylsulfonic acid (as alkali salt), N-amino-ethylethylenediamine- (1,2) (diethylenetriamine) bis- (N, N'-aminoethyl) -ethylenediamine- (1,2) (triethylenetetramine), hydrazine and its salts are also referred to as diamines in the present context.

Beispiele für die eingekapselten Farbbildner sind Triphenylmethanverbindungen, Diphenylmethanverbindungen, Xanthenverbindungen, Thiazinverbindungen und Spiropyranverbindungen.Examples of the encapsulated color formers are triphenylmethane compounds, diphenylmethane compounds, xanthene compounds, thiazine compounds and spiropyran compounds.

Beispiele für Triphenylmethanverbindungen sind 3,3-Bis-(p-dimethylaminophenyl)-6-dimethylaminophthalid (= Kristallviolettlacton, nachstehend als C.V.L. bezeichnet) und 3,3-Bis-(p-dimethylaminophenyl)-phthalid (Malachitgrünlacton).Examples of triphenylmethane compounds are 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (= crystal violet lactone, hereinafter referred to as C.V.L.) and 3,3-bis- (p-dimethylaminophenyl) phthalide (malachite green lactone).

Beispiele für Diphenylmethanverbindungen sind 4,4'-bis-dimethylaminobenzhydrylbenzylether, N-Halogenphenylleucolamin, N-ß-Naphthylleucolamin, N-2,4,5-Trichlorphenylleucolamin und N-2,4-Dichlorphenolleucolamin.Examples of diphenylmethane compounds are 4,4'-bis-dimethylaminobenzhydrylbenzylether, N-halophenylleucolamine, N-ß-naphthylleucolamine, N-2,4,5-trichlorophenylleucolamine and N-2,4-dichlorophenolleucolamine.

Beispiele für Xanthenverbindungen sind Rhodamin-ß-anilinolactam, Rhodamin-ß-(p-nitroanilin)-lactam, Rhodamin-β-(p-chloranilin)-lactam, 7-Dimethyl-amin-2-methoxifluoran, 7-Diethylamin-3-methoxifluoran, 7-Diethylamin-3-methyl-fluoran, 7-Diethylamin-3-chlorfluoran, 7-Diethylamin-3-chlor-2-methylfluoran, 7-Diethylamin-2,4-dimethylfluoran, 7-Diethylamin-2,3-dimethylfluoran, 7-Diethylamin-(3-acetyl-methylamin)-fluoran, 7-Diethyl-amin-3-(dibenzylamin)-fluo-ran, 7-Diethylamin-3-(methylbenzylamin)-fluoran, 7-Diethyl-amin-3-(chlorethylmethylamino)-fluoran, 7-Diethylamin-3-(dichlorethyl-amin)-fluoran, 7-Diethylamin-3-(diethylamin)-fluoran.Examples of xanthene compounds are rhodamine-β-anilinolactam, rhodamine-β- (p-nitroaniline) lactam, rhodamine-β- (p-chloroaniline) lactam, 7-dimethylamine-2-methoxifluorane, 7-diethylamine-3- methoxifluorane, 7-diethylamine-3-methyl-fluorane, 7-diethylamine-3-chlorofluorane, 7-diethylamine-3-chloro-2-methylfluorane, 7-diethylamine-2,4-dimethylfluorane, 7-diethylamine-2,3- dimethylfluorane, 7-diethylamine- (3-acetyl-methylamine) -fluorane, 7-diethylamine-3- (dibenzylamine) -fluoro-ran, 7-diethylamine-3- (methylbenzylamine) -fluoroane, 7-diethylamine 3- (chloroethylmethylamino) -fluorane, 7-diethylamine-3- (dichloroethyl-amine) -fluorane, 7-diethylamine-3- (diethylamine) -fluorane.

Beispiele für Thiazinverbindungen sind N-Benzoyl-leucomethylenblau, o-Chlorbenzoylleucomethylenblau, p-Nitrolbenzoylleucomethylenblau.Examples of thiazine compounds are N-benzoyl-leucomethylene blue, o-chlorobenzoylleucomethylene blue, p-nitrolbenzoylleucomethylene blue.

Beispiele für Spiroverbindungen sind 3-Methyl-2,2'-spirobis-(benzo(f)-chromen), 3-Ethyl-spirodinaphthopyran.Examples of spiro compounds are 3-methyl-2,2'-spirobis (benzo (f) chromium), 3-ethyl-spirodinaphthopyran.

Lösungsmittel, die diese Farbbildner lösen, sind z.B. chloriertes Diphenyl, chloriertes Paraffin, Baumwollsamenöl, Erdnußöl, Silikonöl, Phthalatester, Phosphatester, Sulfonatester, Monochlorbenzol, ferner teilhydrierte Terphecyle, alkylierte Naphthaline, Arylether, Arylalkylether, höher alkyliertes Benzol und andere, die allein oder kombiniert eingesetzt werden können.Solvents that dissolve these color formers are e.g. chlorinated diphenyl, chlorinated paraffin, cottonseed oil, peanut oil, silicone oil, phthalate ester, phosphate ester, sulfonate ester, monochlorobenzene, furthermore partially hydrogenated terphecyle, alkylated naphthalenes, aryl ethers, aryl alkyl ethers, higher alkylated benzene and others which can be used alone or in combination.

Häufig werden den Lösungsmitteln Verdünnungsmittel zugesetzt, wie z.B. Kerosin, n-paraffine, Isoparaffine.Diluents are often added to the solvents, e.g. Kerosene, n-paraffins, isoparaffins.

Zur Herstellung der Mikrokapseln nach dem Polyadditionsverfahren werden zunächst die Farbgeber und das Isocyanat in den genannten Lösungsmitteln gelöst und diese organische Phase in der kontinuierlichen wäßrigen Phase, die Schutzkolloid und gegebenenfalls Emulgatoren enthalten kann, emulgiert. Zur Emulsion gibt man eine wäßrige Polyaminlösung in stöchiometrischer Menge zum Polyisocyanat in der organischen Phase.To produce the microcapsules by the polyaddition process, the colorants and the isocyanate are first dissolved in the solvents mentioned and this organic phase is emulsified in the continuous aqueous phase, which may contain protective colloid and, if appropriate, emulsifiers. An aqueous polyamine solution is added to the emulsion in a stoichiometric amount to the polyisocyanate in the organic phase.

Zur Emulgierung und Stabilisierung der gebildeten Emulsion werden der wäßrigen Phase Schutzkolloide und Emulgierhilfsmittel zugesetzt. Beispiele für solche, als Schutzkolloide wirkende Produkte sind Carboximethylcellulose, Gelatine und Polyvinylalkohol.Protective colloids and emulsifying aids are added to the aqueous phase to emulsify and stabilize the emulsion formed. Examples of such products acting as protective colloids are carboxymethyl cellulose, gelatin and polyvinyl alcohol.

Beispiele für Emulgatoren sind oxethyliertes 3-Benzyl-hydroxibiphenyl, Umsetzungsprodukte von Nonylphenol mit unterschiedlichen Mengen Ethylenoxid und Sorbitanfettsäureester.Examples of emulsifiers are ethoxylated 3-benzyl-hydroxibiphenyl, reaction products of nonylphenol with different amounts of ethylene oxide and sorbitan fatty acid ester.

Die Mikrokapseln können kontinuierlich oder diskontinuierlich hergestellt werden. Man verwendet im allgemeinen Dispergiergeräte, die ein Schergefälle erzeugen. Beispiele hierfür sind Blatt-, Korb-, Schnellrührer, Kolloidmühlen, Homogenisatoren, Ultraschalldispergatoren, Düsen, Stahldüsen, Supratonmaschinen. Die Stärke der Turbulenz beim Vermischen ist in erster Linie bestimmend für den Durchmesser der erhaltenen Mikrokapseln. Kapseln in der Größe von 1 bis 2000 um können hergestellt werden. Bevorzugt sind Kapseln mit Durchmessern von 2 bis 20 µm. Die Kapseln agglomerieren nicht und haben eine enge Teilchengrößenverteilung. Das Gewichtsverhältnis von Kernmaterial zu Hüllenmaterial ist 50 bis 90 zu 50 bis 10.The microcapsules can be produced continuously or batchwise. Dispersing devices which generate a shear gradient are generally used. Examples include blade, basket, high-speed stirrers, colloid mills, homogenizers, ultrasonic dispersers, nozzles, steel nozzles, and Supraton machines. The strength of the turbulence during mixing is primarily decisive for the diameter of the microcapsules obtained. Capsules from 1 to 2000 µm in size can be made. Capsules with diameters of 2 to 20 μm are preferred. The capsules do not agglomerate and have a narrow particle size distribution. The weight ratio of core material to shell material is 50 to 90 to 50 to 10.

Die Mikrokapseln fallen im allgemeinen als wäßrige Suspension an. Man kann z.B. durch Sprühtrocknung daraus die Mikrokapseln als agglomeratfreie Pulver isolieren.The microcapsules are generally obtained as an aqueous suspension. You can e.g. isolate the microcapsules as agglomerate-free powder by spray drying.

Zur Herstellung der Zubereitung für den Flexodruck kann man die Komponenten - Mikrokapselpulver, Lösungsmittel und Bindemittel - in üblichen Mischaggregaten vermischen. Dabei löst sich das Bindemittel im Lösungsmittel auf, und die Mikrokapseln verteilen sich homogen in dieser Mischung. Es ist überraschend, daß auf diese Weise eine stabile und gleichmäßige Verteilung der Mikrokapseln erreicht werden kann, denn die unpolaren Lösungsmittel und die polaren Mikrokapseln sind an sich unverträglich.To prepare the preparation for flexographic printing, the components - microcapsule powder, solvent and binder - can be mixed in conventional mixing units. The binder dissolves in the solvent and the microcapsules are distributed homogeneously in this mixture. It is surprising that a stable and uniform distribution of the microcapsules can be achieved in this way, since the non-polar solvents and the polar microcapsules are inherently incompatible.

Man kann auch in die wäßrige Suspension der Mikrokapseln das Lösungsmittel und das Bindemittel einbringen und das Wasser dann im Vakuum abziehen (Flushing-Verfahren).The solvent and the binder can also be introduced into the aqueous suspension of the microcapsules and the water can then be drawn off in a vacuum (flushing process).

Hierbei kann das Lösungsmittel bereits einen Bestandteil oder mehrere Bestandteile der Druckfarbe enthalten.The solvent may already contain one or more components of the printing ink.

Die Menge an Mikrokapseln, die in die Formulierung eingearbeitet wird, richtet sich nach den Anforderungen, die an die fertige Druckfarbe gestellt werden müssen. Die Menge an Kapseln wird nach dem erfindungsgemäßen Verfahren so hoch eingestellt, wie es unter Berücksichtigung der Rheologie der fertigen Druckfarbe vertretbar ist, um andererseits mit einem möglichst geringen Beschichtungsgewicht eine optimale Menge an Mikrokapseln aufzubringen.The amount of microcapsules that is incorporated into the formulation depends on the requirements that must be placed on the finished printing ink. The amount of capsules is set according to the method of the invention as high as is reasonable considering the rheology of the finished printing ink, in order to apply an optimal amount of microcapsules with the lowest possible coating weight.

Die Flexodruckfarben können normalerweise mit einfachen Rührwerken, Schnellrührern und/oder Hochleistungsrührern hergestellt werden.The flexographic printing inks can normally be produced with simple stirrers, high-speed stirrers and / or high-performance stirrers.

Die Einarbeitung der einzelnen Komponenten der Druckfarben kann in beliebiger Reihenfolge durchgeführt werden.The incorporation of the individual components of the printing inks can be carried out in any order.

Bei der Verarbeitung der Mikrokapselpulver können nach dem erfindungsgemäßen Verfahren Bindemittel eingesetzt werden, die nach bekanntem Stand der Technik zur Herstellung einer im Flexodruck verarbeitbaren Druckfarbe benutzt werden. Außerdem kommen zahlreiche natürliche oder synthetische Harze in Frage, wie sie für die Herstellung von Druckfarben verwendet werden, die sich nach anderen Drucktechniken als dem Flexodruck verarbeiten lassen. z.B. im Buch-, Tief-, Flach- und Durchdruck.In the processing of the microcapsule powder, binders can be used according to the method according to the invention, which binders are used according to the known prior art for producing a printing ink which can be processed in flexographic printing. There are also numerous natural or synthetic resins that can be used for the production of printing inks that can be processed using printing techniques other than flexographic printing. e.g. in book, gravure, flat and printing.

Geeignete Lösungsmittel bzw. Lösungsmittelgemische sind aromatische und aliphatische Kohlenwasserstoffe, halogenierte aromatische und aliphatische Kohlenwasserstoffe, sowie Ether. Sie sind bei 20°C flüssig und besitzen Siedepunkte zwischen 50 und 180°C.Suitable solvents or solvent mixtures are aromatic and aliphatic hydrocarbons, halogenated aromatic and aliphatic hydrocarbons and ethers. They are liquid at 20 ° C and have boiling points between 50 and 180 ° C.

Beispiele hierfür sind Waschbenzin, Testbenzine, Spezialbenzine, n-Pentan, n-Hexan, Cyclohexan, Ligroin, Petrolether, Leichtbenzin, Tetrachlorkohlenstoff, Perchlorethylen, Cumol, Chlorbenzol, Methyl-tert.-butylether, tert.-Amylmethylether.Examples include white spirit, white spirit, special gasoline, n-pentane, n-hexane, cyclohexane, ligroin, petroleum ether, light petrol, carbon tetrachloride, perchlorethylene, cumene, chlorobenzene, methyl tert-butyl ether, tert-amyl methyl ether.

Geeignete Bindemittel sind:

  • - Cyclokautschuke, die bei Behandlung von Naturkautschuk mit Schwefelsäure, organischen Sulfonsäuren oder Sulfochloriden, Metallhalogeniden oder Bortrifluorid entstehen und ein Molekulargewicht von 1500 bis 10.000, bevorzugt 2000 bis 5000 aufweisen.
  • - Polyamidharze, die man durch Umsetzung von verzweigten Dicarbonsäuren mit Polyaminen erhält, und die ein Molekulargewicht von etwa 10.000 haben. Die Dicarbonsäuren werden durch Polymerisation von natürlichen, einfach und/oder mehrfach ungesättigten Fettsäuren oder deren Methylester, z.B. Olein, Tallölfettsäure, Sojaöl-und Baumwollsaatölfettsäure hergestellt, wie sie in den DE-PS 1 134666,1 134667,1 280 852,1 443 938 und der DE-AS 1 443 968 beschrieben werden. Die Herstellung von Polyamidharzen erfolgt im allgemeinen durch Kondensation der polymeren Fettsäuren mit Polyaminen der Formel
    • NH2-(CH2)d NH(CH2).ly-NH2
    • x=2-6
    • γ-0-3

    und wird beschrieben in den DE-PS 1 520 933 und 1 745 556, in der DE-AS 1 745 447, in den DE-OS 1 645 414
    und 1 720 819 und in der US-PS 2 450 940.
Suitable binders are:
  • - Cyclo-rubbers which are formed when natural rubber is treated with sulfuric acid, organic sulfonic acids or sulfochlorides, metal halides or boron trifluoride and have a molecular weight of 1500 to 10,000, preferably 2000 to 5000.
  • - Polyamide resins which are obtained by reacting branched dicarboxylic acids with polyamines and which have a molecular weight of about 10,000. The dicarboxylic acids are prepared by polymerizing natural, mono- and / or polyunsaturated fatty acids or their methyl esters, for example olein, tall oil fatty acid, soybean oil and cottonseed oil fatty acid, as described in DE-PS 1 134666.1 134667.1 280 852.1 443 938 and DE-AS 1 443 968 can be described. Polyamide resins are generally produced by condensation of the polymeric fatty acids with polyamines of the formula
    • NH2- (CH2) d NH (CH 2 ) .ly-NH 2
    • x = 2-6
    • γ-0-3

    and is described in DE-PS 1 520 933 and 1 745 556, in DE-AS 1 745 447, in DE-OS 1 645 414
    and 1 720 819 and in U.S. Patent 2,450,940.

Durch die zusätzliche Verwendung von Codicarbonsäuren, wie z.B. Adipinsäure oder Terephthalsäure und/oder Codiaminen, sowie durch die Variation des Reinheitsgrades der polymeren Fettsäuren können die Eigenschaften der resultierenden Polyamide beeinflußt werden. Bevorzugt werden Kondensationsprodukte auf Basis von dimerer Fettsäure und Ethylendiamin.

  • - Copolymerisate aus Styrol mit Alkyl(meth)acrylaten. Bevorzugt werden solche Produkte, die man durch Mischpolymerisation von Styrol oder substituierten Styrolen mit Esterri von (Meth)Acrylsäure und Alkoholen mit mehr als 8 C-Atomen erhält, wie es z.B. in der DE-AS 1 006 158 beschrieben wird.
  • - Bestimmte Polyurethane, die Mischungen von sowohl freie Hydroxylgruppen als auch ungesättigte Fettsäurereste aufweisenden Alkydharzen mit modifizierten Polyisocyanaten enthalten. Bevorzugt werden als modifizierte Polyisocyanate Polyadditionsverbindungen von Di- und/ oder Polyisocyanaten und Hydroxylgruppen aufweisenden Teilestern, die aus mehrwertigen Alkoholen und mehr als 20 Gew.-% 2- und/oder 3-fach ungesättigte Fettsäuren aufweisenden Hydroxylgruppen-freien Fettsäuregemischen bzw. 2- und/oder 3-fach ungesättigten hydroxylgruppen-freien Fettsäuren bereitet werden und u.a. in der DE-AS 2111 191 beschrieben werden.
The properties of the resulting polyamides can be influenced by the additional use of codicarboxylic acids, such as adipic acid or terephthalic acid and / or codiamines, and by varying the degree of purity of the polymeric fatty acids. Condensation products based on dimeric fatty acid and ethylenediamine are preferred.
  • - Copolymers of styrene with alkyl (meth) acrylates. Preference is given to products which are obtained by copolymerizing styrene or substituted styrenes with esters of (meth) acrylic acid and alcohols having more than 8 carbon atoms, as described, for example, in DE-AS 1 006 158.
  • - Certain polyurethanes containing mixtures of both free hydroxyl groups and unsaturated fatty acid residues containing alkyd resins with modified polyisocyanates. Preferred modified polyisocyanates are polyaddition compounds of di- and / or polyisocyanates and hydroxyl group-containing partial esters, the hydroxyl group-free fatty acid mixtures or 2- and / or from polyhydric alcohols and more than 20% by weight having hydroxyl group-free and / or triple unsaturated fatty acids / or triple unsaturated hydroxyl-free fatty acids are prepared and are described, inter alia, in DE-AS 2111 191.

Zur Verwendung von Druckformen und Druckwalzen können bei dem erfindungsgemäßen Verfahren solche Materialien eingesetzt werden, wie sie von Dieter Breuer u. Joachim Petersen in dem Buch "Der Flexodruck" 2. erweiterte Auflage 1974 P. Keppler Verlag KG, 6056 Heusenstamm bei Frankfurt am Main, erwähnt werden. Außerdem sind Polyurethanmassen in offenzelliger, geschlossenzelliger oder massiver Form für Druckformen bzw. Druckwalzen geeignet, wobei sich die jeweils erforderlichen Eigenschaften nach bekannten Verfahren der Polyurethanchemie einstellen lassen.To use printing formes and printing rollers, such materials can be used in the method according to the invention, as described by Dieter Breuer u. Joachim Petersen in the book "Der Flexodruck" 2nd extended edition 1974 P. Keppler Verlag KG, 6056 Heusenstamm near Frankfurt am Main. In addition, polyurethane compositions in open-cell, closed-cell or solid form are suitable for printing forms or printing rollers, the properties required in each case being able to be set by known processes in polyurethane chemistry.

Weitere geeignete Materialien sind Isopren-Kautschuk, Acrylnitril-Butadien-Kautschuk, und Ethylen-Propylen-Dien-Kautschuk.Other suitable materials are isoprene rubber, acrylonitrile-butadiene rubber, and ethylene-propylene-diene rubber.

Zur Verhinderung der Agglomeration der Mikrokapseln können der Druckfarbe Dispergierhilfsmittel, vorzugsweise aus der Gruppe der kationischen Tenside zugesetzt werden.To prevent agglomeration of the microcapsules, dispersing aids, preferably from the group of the cationic surfactants, can be added to the printing ink.

Um Zerstörungen der Mikrokapseln beim Herstellen der Druckfarbe und beim Druckvorgang selbst zu verhindern, werden in einer bevorzugten Ausführungsform sogenannte Abstandshalter in Mengen von 2 - 20 Gew.-% der Druckfarbe zugesetzt. Diese Abstandshalter werden nach bekanntem Stand der Technik auch bei der Herstellung der üblichen kohlefreien Durchschreibepapiere verwendet. Sie können beispielsweise aus Cellulosefaserpartikeln oder Stärkekörnern, deren Durchmesser in der Regel das 1,5 bis 5-fache der Mikrokapseldurchmesser beträgt, bestehen.In order to prevent the microcapsules from being destroyed during the production of the printing ink and during the printing process itself, in a preferred embodiment, so-called spacers are added to the printing ink in amounts of 2-20% by weight. According to the known state of the art, these spacers are also used in the production of the usual carbonless carbonless papers. For example, they can consist of cellulose fiber particles or starch granules, the diameter of which is usually 1.5 to 5 times the microcapsule diameter.

Als weitere Zusatzmittel können beispielsweise Pigmente und Hilfsmittel, die die Opazität der Beschichtung günstig beeinflussen, zugesetzt werden.Pigments and auxiliaries which have a favorable effect on the opacity of the coating can be added as further additives.

Beim Einsatz langsam laufender Druckmaschinen, übergroßer Klischeezylinder oder besonders stark saugender "Druckträger" können Trocknungsverzögerer mitbenutzt werden. Schnelltrockner bzw. Beschleuniger werden dann eingesetzt, wenn extrem hohe Druckgeschwindigkeiten erreicht werden sollen.When using slow-running printing presses, oversized plate cylinders or particularly strongly absorbent "print carriers", drying retarders can also be used. Fast dryers and accelerators are used when extremely high printing speeds are to be achieved.

Beispielexample

Es wurde eine 30%ige wäßrige Mikrokapseldispersion hergestellt, deren Mikrokapselwände aus einem Polyadditionsprodukt aus dem Oxadiazintrion von Hexamethylendiisocyanat und einem Polyamin bestanden. Der Kapselinhalt war eine Lösung von 2,7 % Kristallviolettlacton und 0,9 % N-Benzoylleukomethylenblau in DiIsopropyl-Diphenyl. Das Kern/Wand-Verhältnis der Mikrokapseln betrug 83:17.A 30% aqueous microcapsule dispersion was prepared, the microcapsule walls of which consisted of a polyaddition product of the oxadiazinetrione of hexamethylene diisocyanate and a polyamine. The capsule contents were a solution of 2.7% crystal violet lactone and 0.9% N-benzoyl leukomethylene blue in diisopropyl diphenyl. The core / wall ratio of the microcapsules was 83:17.

Die 30%ige Kapseldispersion wurde durch Sprühtrocknung in ein weitgehend agglomeratfreies Kapselpulver überführt, deren mittlerer Kapseldurchmesser zu 7,3 um bestimmt wurde.The 30% capsule dispersion was converted into a largely agglomerate-free capsule powder by spray drying, the mean capsule diameter of which was determined to be 7.3 μm.

Mit einem Rührwerk (IKA-Rührwerk RW 18 der Fa. Janke + Kunkel) wurden zunächst 800 g Cyclokautschuk (Alpex CK 514 der Fa. Hoechst AG) in 3694 g Tetrachlorkohlenstoff gelöst und anschließend mit 4306 g Waschbenzin (Typ 100/140 der Fa. Shell-Chemie) vermischt. In diese Mischung wurden 1200 g des vorgefertigten Mikrokapselpulvers homogen eingerührt.Using an agitator (IKA agitator RW 18 from Janke + Kunkel), 800 g of cyclo rubber (Alpex CK 514 from Hoechst AG) were first dissolved in 3694 g of carbon tetrachloride and then with 4306 g of benzine (type 100/140 from Fa. Shell chemistry) mixed. 1200 g of the prefabricated microcapsule powder were homogeneously stirred into this mixture.

Die so gefertigte, 12 Gew.-% Mikrokapseln enthaltende Druckfarbe wurde mit einer Flexodruckmaschine auf die Rückseite eines handelsüblichen CF-Papiers (Giroset-CF der Fa. Feldmühle) in Form eines Quadrats von 12 cm Kantenlänge aufgedruckt. Das Auftragsgewicht der Beschichtung betrug bis zu 2,6 g/m2 nach Trocknung, was einer Kapselmenge von ungefähr 1,6 g/m2 entsprach.The printing ink produced in this way, containing 12% by weight of microcapsules, was printed on the back of a commercially available CF paper (Giroset-CF from Feldmühle) in the form of a square of 12 cm edge length using a flexographic printing machine. The application weight of the coating was up to 2.6 g / m 2 after drying, which corresponded to an amount of capsules of approximately 1.6 g / m 2 .

Bei der Beschriftung mehrerer übereinandergelegter, so hergestellter Papiere ließen sich innerhalb der aufgedruckten Fläche bei Anwendung eines normalen Schreibdruckes gut lesbare Durchschriften erzeugen.When writing on several superimposed papers produced in this way, easily legible copies could be produced within the printed area using normal writing.

Claims (1)

  1. Process for the production of pressure-sensitivc carbonless copying papers by flexographic printing, characterised in that a composition which has a content of optionally chlorinated hydrocarbons or ethers which are liquid at 200 C and have a boiling point of 50 - 180°C as the solvents, a content of polymeric binders which are soluble in these solvents and a content of microcapsules containing dye precursors and having an average diameter of 5 - 20 µm, is printed on to part or whole of the surface of a paper by the technique of flexographic printing using a printing block which does not swell in the solvents of the composition and the solvent is then removed.
EP82103255A 1981-04-30 1982-04-19 Production of carbonless copying papers by flexography Expired EP0064204B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3117242 1981-04-30
DE19813117242 DE3117242A1 (en) 1981-04-30 1981-04-30 FLEXO PRINTING INKS FOR THE PRODUCTION OF REACTION COVER PAPERS

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EP0064204A1 EP0064204A1 (en) 1982-11-10
EP0064204B1 true EP0064204B1 (en) 1986-07-23

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EP82103255A Expired EP0064204B1 (en) 1981-04-30 1982-04-19 Production of carbonless copying papers by flexography

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EP (1) EP0064204B1 (en)
JP (1) JPS57185185A (en)
DE (2) DE3117242A1 (en)
ZA (1) ZA822923B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61273985A (en) * 1985-05-30 1986-12-04 Japan Synthetic Rubber Co Ltd Coating composition for pressure-sensitive copy paper
US5022545A (en) * 1990-08-03 1991-06-11 Continental White Cap, Inc. Tamper evident closure
DE4132796C2 (en) * 1991-10-02 1994-02-24 Andre Nuyken Use of a chemical pressure-indicating coating on a carrier material for the production of footprints

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3016308A (en) * 1957-08-06 1962-01-09 Moore Business Forms Inc Recording paper coated with microscopic capsules of coloring material, capsules and method of making
US3432327A (en) * 1964-03-13 1969-03-11 Pilot Pen Co Ltd Pressure sensitive copying sheet and the production thereof
DE2541001A1 (en) * 1975-09-13 1977-03-17 Eupaco Papier Vertrieb Gmbh & Transfer copying paper prodn. process - uses microencapsulation and reaction substance present in preselected zones on carrier paper
JPS532108A (en) * 1976-06-28 1978-01-10 Fuji Photo Film Co Ltd Method of producing pressure sensitixed copy sheets
DE2930408A1 (en) * 1979-07-26 1981-02-12 Bayer Ag REACTION COVER PAPER

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JPH0359836B2 (en) 1991-09-11
EP0064204A1 (en) 1982-11-10
DE3117242A1 (en) 1982-11-18
JPS57185185A (en) 1982-11-15
ZA822923B (en) 1983-03-30
DE3272101D1 (en) 1986-08-28

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