Classifications

• • 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
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
  • B41M5/42—Intermediate, backcoat, or covering layers

Definitions

• the invention relates to a heat-sensitive recording material with a substrate, a heat-sensitive recording layer containing color formers and color acceptors and a protective layer formed on the recording layer, and to its use as a ticket.
• a heat-sensitive recording sheet of the type mentioned is known from EP-ß-0909242.
• the protective layer of the recording sheet which can be used as a label, receipt or ticket and can be easily printed using the wet offset process, has in particular bentonite as a pigment
• the binder content consists largely of water-insoluble binder in the form of a polymer dispersion and consists to a lesser extent of an aqueous solution of a polymer.
• natural calcium carbonate, precipitated calcium carbonate, silicon dioxide, atomic oxide and titanium oxide are disclosed as further pigments in the protective layer.
• polyvinyl alcohol is preferably mentioned as the water-soluble binder
• the water-insoluble binders are preferably self-crosslinking copolymers of acrylonitrile methacrylamide and acrylic ester.
• a protective layer is known from EP-A-0 344705, in which 0.5 to 3 parts by weight of pigment are present per part by weight of binder.
• Suitable binders for the protective layer include polyvinyl alcohol, carboxymethyl methulose, starch and starch derivatives, and copolymer emulsions of styrene-butadiene, vinyl acetate-ethylene, vinyl acetate-vinyl chloride-ethylene and methacrylic butadiene.
• Precipitated calcium carbonate, ground calcium carbonate, talc, kaolin, silicon dioxide anhydride, magnesium carbonate, zinc oxide, aluminum oxide and aluminum hydroxide in addition to organic pigments are mentioned as suitable pigments.
• EP-B-0373903 relates to a heat-sensitive recording paper with an internal adhesive strength of 2.5 kgcm or more, which has a protective layer with a smoothness of at least 500 Bekk-seconds, preferably from 700 to 1500 Bekk-seconds, on a fine particle of a Styrene-acrylate polymer and an intermediate layer containing a binder is applied.
• Suitable binders for the protective layer are both water-soluble and water-insoluble high polymers with sufficient film-forming capacity. Any pigment addition to the protective layer is also disclosed, but the document does not provide any indication of the type of suitable pigments.
• the new recording material must be characterized by a high level of environmental resistance.
• An essential part of the new recording material must be its cost-effective production method.
• the invention sees its task in developing a recording material which, in addition to the range of requirements listed above, also has excellent printability the entire surface of the protective layer at the points where a validation print is not provided.
• a heat-sensitive recording material having a substrate, a heat-sensitive recording layer containing color formers and color acceptors and a protective layer formed on the recording layer, with a full-surface, locally limited coating is printed.
• a particularly suitable embodiment of the present invention provides for the single-layer formation of the protective layer for economic reasons.
• the thermal head which triggers the color-forming reaction of the color formers with the color acceptors in the heat-sensitive recording layer causes the wax-like constituents in the recording layer to melt.
• an intermediate layer containing a pigment or a pigment mixture be formed between the heat-sensitive recording layer and the substrate, the pigments of this intermediate layer causing the melt to be absorbed. It is particularly advantageous if the pigment of the intermediate layer of at least 80 cm3 / 100 g, and more preferably of 100 cm, having an oil absorption 3/100 g, determined according to the Japanese standard JIS K 5,101th Calcined kaolin has proven particularly useful due to its large absorption reservoir in the cavities.
• an intermediate layer formed in this way acts as a heat reflection layer, as a result of which the heat sensitivity of the recording material and thus the Print speed in the thermal printer can be increased. Furthermore, such an intermediate layer can make a positive contribution to the leveling of the substrate surface, thus reducing the amount of coating color which is necessarily to be applied for the heat-sensitive recording layer.
• the formation of an intermediate layer with a mass per unit area in a range from 5 to 20 g / m 2 and even better between 7 and 10 g / m 2 has a particularly advantageous effect.
• a coating color as proposed in P-B-0 909 242, is well suited for forming the protective layer for the new recording material.
• Such a protective layer combines high environmental resistance with excellent printability in the wet offset process.
• the protective layer is also relatively inexpensive to manufacture and apply in one layer.
• the pigment of the protective layer consists of one or more inorganic pigments and at least 80% by weight is formed from a highly purified alkaline bentonite,
• the binder of the protective layer consists of one or more water-insoluble, self-crosslinking acrylic polymers,
• the binder-Z pigment ratio in the protective slide is in a range between 7: 1 and 9: 1,
• the crosslinking agent / binder ratio in the protective layer is greater than 1: 5 and preferably between 1: 5 and 1: 7 and
• the protective layer has a smoothness of at least 900 Bekk seconds. Natural or precipitated calcium carbonate, kaolin or titanium oxide are possible as further inorganic pigments for the protective layer. Cyclic urea, methylol urea, polyamide epichlorohydrin resin and ammonium zirconium carbonate are particularly suitable as crosslinking agents for the protective layer.
• An embodiment explained above ensures a heat-sensitive recording material which has good printhead behavior over the entire area and whose protective layer at the same time has good environmental resistance and excellent printability in the flexographic and wet offset processes.
• the protective layer with a mass per unit area in a range from 1.5 to 6 g / m 2 and in particular between 1.8 and 4 g / m 2 .
• the recording material according to the invention preferably has a backside coating which is applied to the substrate side which is opposite the side provided with the heat-sensitive recording layer.
• a back coating is proposed, for example, in DE-A-9748258 and then serves to improve the printability of the recording sheet on the back in the offset and flexographic printing processes and to improve the blocking effect of the back against plasticizers, oils and greases.
• application quantities in a range from 1 to 3 g / m 2 and especially between 1.5 and 2.5 g / m 2 have proven to be advantageous.
• the full-surface, localized so-called “spot” coating is preferably a rectangle on the edge fitted in the form of as a ticket, that is printed and printed cut heat-sensitive recording material.
• the used therefor ink preferably contains pigments having an oil absorption of at least 80 cm3 / 100 g determined according to the Japanese standard JIS K 5101. As already explained above, it is advantageous to choose a greater oil absorption of the pigments in the intermediate layer than the oil absorption of the pigments in the "spot” coating.
• Another preferred embodiment provides that the printing ink applied as a “spot” coating is 60 to 90% by weight. of pigment having an oil absorption of at least 80 cm3 / 100 consists g.
• Further constituents of the water-based printing inks for the "spot" coating are alcohols such as isopropanol or ethanol as solvents and, for example, maleate, polyester and acrylate resins as binders, the carboxyl groups of which are saponified with aqueous ammonia or with amines and in water-soluble salts
• alcohols such as isopropanol or ethanol as solvents
• maleate, polyester and acrylate resins as binders
• the carboxyl groups of which are saponified with aqueous ammonia or with amines and in water-soluble salts
• paper is the substrate which has also become established on the market with a view to its good environmental compatibility due to its good recyclability and which is preferred in the sense of the invention.
• the heat-sensitive recording material according to the invention is mainly designed for use as a ticket and here in particular as a ticket.
• the passenger pushes the ticket into a dedicated validation machine so that the validation print is applied to the full-surface, locally limited so-called "spot" coating.
• the validation print is dry-wiped, so that there is no risk of the passenger getting dirty on the inadequately fixed printing ink, and at the same time the printing for control purposes can always be easily deciphered.
• DE-A-199 36030 provides an overview of authenticity features that can be used individually or in combination, but is not limited to the suggestions made there.
• the information given in the description and in the claims on the mass per unit area and on% by weight (% by weight) relates in each case to the “at ⁇ weight”, ie absolutely dry parts by weight.
• a single value determination provides that a DIN A4 sample is first cut.
• the ratio of two measurements of the dynamic pressure density determined using the Macbeth RD 914 from Karl Schröder KG (Korrillonstrasse 32, D-69469 Weinheim) is recorded.
• the sample is provided with a typeface using a TP 3000-300 thermal printer from Charles Richiger AG V Maschinenbau (Bemstrasse 81 ⁇ CH-3613 Steffisburg).
• Exposure time see table The excess medium is then suctioned off or dabbed off. Medium already taken up by the sample is left to act for a certain time (rest period before measurement see table).
• the dynamic print density is measured a second time.
• the arithmetic mean is drawn from the 3 individual values determined in this way.
• the media resistance examined can be described as very good if the arithmetic mean of the quotients determined from two measurement values in each case is greater than the “limit value of image stability” according to Table 1.
• a paper web made of bleached and ground hardwood and softwood cellulose with a mass per unit area of 67 g / m 2 is added to the substrate on a Fourdrinier paper machine with the addition of conventional admixtures in conventional quantities.
• a calcined kaolin as a pigment, styrene-butadiene latex as a binder and starch as a cobinder are applied to the front in addition to an additional intermediate layer of 8 g / m 2 .
• a heat-sensitive recording layer containing color formers and color acceptors and having a mass per unit area of 5.4 g / m 2 is applied to the intermediate layer.
• a protective layer of 2 g / m 2 is applied to the dried recording layer.
• the pigment used is a highly purified, alkaline-processed bentonite with a platelet structure, the self-adhesion of which enables it to be fixed with little need for binding agents, and the specific surface area of which, in the undispersed state, is stated to be 85 m 2 / g with an area-to-edge ratio which corresponds to Bentonite in powder form is in a range of between 20 and 50.
• a binder / pigment ratio of 6: 1 and a crosslinking agent / binder ratio of 1: 5 are set.
• the coating slip for the production of the protective layer contains, as further components, a defoamer, stearic acid as a lubricant and various dispersants, on the one hand for the pigment and on the other hand for the lubricant.
• the applied coating slip is dried and the record sheet produced so far is smoothed using a calender, with a smoothness of 2200 Bekk seconds being achieved.
• the side of the heat-sensitive recording material according to the invention which has been provided with a protective layer is checked for its environmental resistance at the points not printed with a "spot" coating and is determined to be very good. After 10 seconds, the wipe proof is checked for smudge resistance with a damp finger; the stamp cannot be blurred.
• Figure 1 shows the schematic structure of the heat-sensitive recording material according to the invention in cross section.
• a back coating (2) is applied to the underside of the substrate (1).
• An intermediate layer (3), a heat-sensitive recording layer (4) and a protective layer (5) are applied to the front of the substrate (1) in the order shown here.
• a full-area, locally limited print job (6) is arranged on the protective layer.
• Figure 2 shows an example of the heat-sensitive recording material according to the invention cut to the ticket in the plan.
• the protective layer (5) which can only be recognized in the plan, the full-area, locally limited print job (6) is applied in the form of a rectangle, the long side of which is parallel to one Extra line of the ticket is arranged.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Heat Sensitive Colour Forming Recording (AREA)

Applications Claiming Priority (3)

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• 2001
  • 2001-02-23 DE DE10108982A patent/DE10108982A1/de not_active Withdrawn
• 2002
  • 2002-02-20 US US10/468,634 patent/US7008902B2/en not_active Expired - Lifetime
  • 2002-02-20 ES ES02722100T patent/ES2235028T3/es not_active Expired - Lifetime
  • 2002-02-20 DE DE50201836T patent/DE50201836D1/de not_active Expired - Lifetime
  • 2002-02-20 EP EP02722100A patent/EP1363786B1/fr not_active Expired - Lifetime
  • 2002-02-20 JP JP2002567546A patent/JP2004520974A/ja active Pending
  • 2002-02-20 AT AT02722100T patent/ATE285335T1/de not_active IP Right Cessation
  • 2002-02-20 WO PCT/EP2002/001756 patent/WO2002068207A1/fr active IP Right Grant

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