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
  • B41M5/30—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers
  • B41M5/333—Colour developing components therefor, e.g. acidic compounds
  • B41M5/3333—Non-macromolecular compounds
  • B41M5/3335—Compounds containing phenolic or carboxylic acid groups or metal salts thereof
• • 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
  • B41M5/30—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers
  • B41M5/32—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers one component being a heavy metal compound, e.g. lead or iron
• • 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
• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
  • G09F3/00—Labels, tag tickets, or similar identification or indication means; Seals; Postage or like stamps
  • G09F3/02—Forms or constructions
  • G09F3/0291—Labels or tickets undergoing a change under particular conditions, e.g. heat, radiation, passage of time
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M2205/00—Printing methods or features related to printing methods; Location or type of the layers
  • B41M2205/04—Direct thermal recording [DTR]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M2205/00—Printing methods or features related to printing methods; Location or type of the layers
  • B41M2205/38—Intermediate layers; Layers between substrate and imaging layer
• • 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
  • B41M5/30—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers
  • B41M5/337—Additives; Binders
  • B41M5/3377—Inorganic compounds, e.g. metal salts of organic acids

Definitions

• the present invention refers to a thermosensitive recording sheet for labeling foodstuff having direct contact with said foodstuff.
• the thermosensitive recording sheet comprises a composition that is not detrimental according to the regulations in respect of substances in direct contact with foodstuff.
• thermoprinter For printing a label, for instance, a thermoprinter and a thermosensitive printing sheet is needed.
• the thermosensitive recording material generally comprises a supporting substrate, for example, a paper sheet, synthetic paper sheet, or plastic resin film.
• a thermosensitive image forming layer is formed on the surface of the supporting substrate.
• Said layer generally comprises a dye precursor, such as a leuco basic dye, an acidic color developing agent, such as a phenolic compound, and a binder. Colored images are recorded on such a recording material by reaction of the dye precursor with the color developing agent upon heating.
• a heat-sensitive recording material that is useful, for example, in the manufacture of labels used in connection with the sale of meat, produce, and the like.
• the material comprises a cellulosic or other suitable substrate, a thermally imprintable color producing layer, and a water-insoluble protective layer over the color-producing layer.
• the color-producing layer comprises a colorless or pale leuco dye, an acidic developer for producing an image upon heating of the recording material, a binder and a basic, particulate, neutralizing agent.
• the water-insoluble protective layer affixed to said color-producing layer comprises an organic-acid catalyzed cross-linked resin containing dispersed spacer particles.
• Such a label can be affixed to a package containing meat products. Meat discoloration beneath the label, know as "meat bloom", is avoided due to the sufficient oxygen-permeability of said label.
• the label cannot be affixed directly onto the meat because the ingredients of the thermosensitive layer, i.e. the leuco dye and the acidic developer are detrimental when in contact with meat.
• JP-09150576 discloses a heat-sensitive recording material comprising a substrate provided with a heat-sensitive color developing layer containing a colorless or light colored electron donating precursor and an electron accepting substance capable of reacting with the dye precursor upon heating to cause color development, as the main component.
• a protective layer is applied to said heat-sensitive recording layer.
• a layer containing a styrene/butadiene copolymer and a pigment is applied to the back of the substrate.
• the purpose of the backcoat layer is to provide a heat-sensitive recording material having a water-resistant seal so that it can be affixed as label to a wet surface. Said recording material can be affixed to carcass meat without causing discoloration on said meat. It is not derivable from JP-09150576 that the label has direct contact with the meat and that it is not detrimental when in contact with meat.
• DE-A-19853016 discloses a label for marking meat having a paper substrate of good printability and writability. Said paper substrate has an adhesive backside coating. Coating with the adhesive is carried out such that on each label there is at least one specific area which is coated with the adhesive and at least one specific area that is free of adhesive.
• the object of the alternating coating is to provide a substrate that can be affixed to either wet or dry meat.
• JP-51/24257 discloses a heat-sensitive recording material for the manufacture of copying paper.
• the thermosensitive layer comprises ferric stearate, white pigment, binding resin, gallic acid ester and a reaction inhibitor.
• the coating is applied so that separately a first liquid comprising ferric stearate, white pigment, binding resin and solvent, and a second liquid comprising gallic acid ester, binding resin, reaction inhibitor and solvent, are mixed and then applied to a support and dried to form a heat-sensitive layer. This is because on mixing the first liquid components and the second liquid components together in a ball mill a fogging phenomenon arises. This leads to unexpected reactions.
• reaction inhibitor is used as one of the essential components in the present invention because it inhibits the side reaction of ferric stearate and gallic acid ester in solution.
• the solvents used for preparing the coating composition are generally organic solvents and the gallic acid ester is generally soluble in these solvents.
• the object of the present invention is to provide a thermosensitive recording sheet that is not harmful in direct contact with foodstuff. Especially, the thermosensitive recording layer does not comprise any substances harmful in contact with foodstuff.
• the thermosensitive recording sheet has to be printed using conventional thermal printers.
• thermosensitive recording sheet for labeling foodstuff having direct contact with said foodstuff comprising a substrate and on one surface of said substrate at least one thermosensitive layer comprising a ferric salt and a water insoluble gallic acid ester.
• a reaction inhibitor is not necessary and therefore absent in said layer.
• thermosensitive recording sheet may comprise a substrate and on one surface of said substrate at least two layers comprising a ferric salt in one layer and a gallic acid ester in the other layer.
• thermosensitive recording layer comprising a ferric salt and a gallic acid ester were applied to a substrate.
• the coating compositon of which the thermosensitive layer is applied to the substrate is preferably a water-based coating composition.
• the gallic acid ester should not be soluble in the fluid phase of the coating composition.
• the gallic acid ester should have a solubility in water at 23°C of less than 5 g/l. It is preferred that the solubility of the gallic acid ester is less than 3,5 g/l, more preferred less than 1,5 g/l and most preferred less than 0,5 g/l in the event that both reactive compounds are present in one layer.
• gallic acid esters can be used having a higher solubility in water.
• the coating weight of the thermosensitive layer is in the range of 5 to 27 g/m 2 , preferably 10 to 22 g/m 2 , and most preferred 15 to 17 g/m 2 .
• thermosensitive recording sheet may comprise at least two layers on the same side of the substrate comprising ferric salt in one layer and gallic acid ester in the other layer.
• the coating weight of each layer is in the range of 3 to 13 g/m 2 , preferably 5 to 11 g/m 2 , and most preferred 7 to 9 g/m 2 .
• an intermediate layer is present between the layer comprising the ferric salt and the layer comprising the gallic acid ester.
• Said intermediate layer may prevent a prereaction of thermosensitive compounds. Additionally, the resistance of the thermosensitive recording sheet to chemical and environmental influence may be improved.
• Said layer can comprise binders such as nitrocellulose, polyurethane, polyvinyl alcohol, vinyl acetates, acrylic latices or mixtures thereof. Additionaly pigments such as silica, alumina or mixtures thereof can be present in said layer.
• the coating weight of said intermediate layer is in the range of 0,3 to 10 g/m 2 , preferably 0,5 to 6 g/m 2 , and most preferred 0,6 to 4 g/m 2 .
• a back-coat may be applied to the side of the substrate opposite to that comprising the layer of ferric salt and gallic acid ester.
• adhesive may be applied to the side of the substrate opposite to that comprising the thermosensitive layer of ferric salt and gallic acid ester, or to the back-coat on the side of the substrate opposite to that comprising the thermosensitive layer of ferric salt and gallic acid ester.
• the adhesive may be applied over the entire area of the side of the substrate opposite to that comprising the thermosensitive layer of ferric salt and gallic acid ester.
• the adhesive may be applied so that there is at least one specific area which is coated with the adhesive and at least one specific area that is free of the adhesive. It is preferred that the area coated with adhesive has an ellipsoidal or circular contour. The purpose of such alternating coating is to provide a thermosensitive recording sheet that can be affixed to either wet or dry meat.
• the adhesive may be any adhesive known not to be detrimental according to the regulations in respect of substances in direct contact with foodstuff, such as polyacrylic latices, derivatives of polyacrylic latices, UV-curable acrylic polymers, derivatives of UV-curable acrylic polymers, acrylic ester polymers, derivatives of acrylic ester polymers or mixtures thereof.
• thermosensitive recording sheet may be present in the thermosensitive recording sheet. It is further preferred that at least one intermediate layer is positioned between the substrate and the layer comprising the ferric salt and/or the gallic acid ester that is a thermal insulating layer known in the prior art.
• the layer may comprise a pigment such as a calcined clay, precipitated calcium carbonate, ground calcium carbonate, titanium dioxide, clay, talc, satin white, gypsum, silica, alumina, plastic pigment, hollow sphere pigment such as Ropaque® (manufactured by Rohm and Haas) or mixtures thereof. Binder, rheology modifier or wet-strength agents may also be present in said layer.
• the coating weight of said intermediate layer is in the range of 1 to 20 g/m 2 , preferably 3 to 10 g/m 2 , and most preferred 5 to 7 g/m 2 .
• a cover layer may be applied to the layer comprising the ferric salt and/or the gallic acid ester.
• the cover layer may comprise a pigment, binder or mixture thereof.
• the coating weight of the cover layer is in the range of 0,1 to 8 g/m 2 , preferably 0,5 to 5 g/m 2 , and most preferred 1 to 3 g/m 2 .
• thermosensitive recording sheet can be applied by processes known to a person skilled in the art such as meyer bar, meyer rod, curtain coating, rotogravure, flexo printing, air brush coating, air knife coating, blade coating, spray coating and combinations thereof.
• the substrate that is the carrier for at least one thermosensitive layer can be paper or board.
• the grammage of the paper or board can vary from 20-400 g/m 2 , preferably 30-200 g/m 2 , more preferred 35-150 g/m 2 , and most preferred 40-90 g/m 2 .
• the fibers used for preparing the paper or board may be of natural or artificial origin.
• a further embodiment of the substrate is to use a non-woven material, such as a valve prepared from fibers of natural or artificial origin.
• the substrate is a synthetic polymeric film, that is a PVC film, a polyethylene film (PE film), a polypropylene film, or a polyester film, like a polyethylene terephthalate film. Said film may be a unidirectional or biaxially oriented film.
• the substrate is paper or board it may have a Cobb value according to DIN 20535 after exposing the substrate for 60 seconds to water of less than 60. It is preferred that the Cobb value is less than 50, more preferred less than 40, even more preferred less than 30 and most preferred less than 20. Additionally, the substrate may be grease resistant.
• the ferric salt used in the thermosensitive recording layer may be a ferric salt of a fatty acid such as ferric stearate (iron (III) stearate).
• the gallic acid ester may be selected from lauryl gallate, stearyl gallate, octyl gallate, cetyl gallate, methyl gallate, ethyl gallate, propyl gallate and mixtures thereof.
• the amount of the ferric salt present in the layer may be in the range of 2 to 10 wt% of the weight of the layer in total. It is preferred that the amount of the ferric salt in the layer is in the range of 4 to 9 , more preferred 5 to 8 , and most preferred 6 to 7 wt% based on the total weight of said layer.
• the amount of the gallic acid ester present in the layer may be in the range of 5 to 20 wt% of the weight of the layer in total. It is preferred that the amount of the gallic acid ester in the layer is in the range of 9 to 17 , more preferred 11 to 15 , and most preferred 12 to 14 wt% based on the total weight of said layer.
• the thermosensitive recording layer may additionally comprise compounds such as binders, pigments, rheology modifiers, dyes, polyurethanes, starches, derivatives of starches, polyvinyl acetates, copolymers of polyvinyl acetates, polyvinyl alcohols, derivatives of polyvinyl alcohols, styrene butadiene latices, acrylic latices, waxes, nitrocellulose or mixtures thereof.
• compounds such as binders, pigments, rheology modifiers, dyes, polyurethanes, starches, derivatives of starches, polyvinyl acetates, copolymers of polyvinyl acetates, polyvinyl alcohols, derivatives of polyvinyl alcohols, styrene butadiene latices, acrylic latices, waxes, nitrocellulose or mixtures thereof.
• thermosensitive recording sheet of the present invention may be affixed directly to the foodstuff.
• Foodstuff in the teaching of the present invention is any foodstuff that is adequate for human consumption. It is preferred that the foodstuff is selected from meat, sausages and similar products, fish, seafood, cheese, vegetables, fruit and baker's ware.
• thermosensitive recording sheet of the present invention is not detrimental can be conducted according to ⁇ 35 of the German "Lebensstoff- und forsussiplace Surprise", EN 1186, EN 13130 and the XXXVI. recommendation for paper and board having contact with foodstuff of the
• All following coating compositions are manufactured using procedures known to a person skilled in the art. Said coating compositions are applied to a substrate by means of meyer rod coating.
• composition of master batch A1 is given in table 1.
• Aerosol OTB was added to a dispersion unit containing a 10 wt-% aqueous solution of Mowiol 4/98 and water. After dissolving the surfactant, lauryl gallate was added and the mixture was dispersed until a homogeneous mixture was obtained.
• the composition of master batch B1 is given in table 2. Aerosol OTB was dispersed in a dispersion unit containing a 10 wt-% aqueous solution of Mowiol 4/98 and water. Iron (III) stearate, and Martinal OL Q 107 were added subsequently. The master batch B1 was dispersed until a homogeneous mixture was obtained.
• master batch A1 comprising the gallic acid ester
• master batch B1 comprising the ferric salt and binder are blended in a reaction vessel and subsequently applied to a substrate.
• the coat weight is in the range of 15 to 17 g/m 2 .
• the composition of the applied coating color and the type of substrate is given in table 3, 4 and 5.
• thermosensitive recording sheets S1 to S16 are suitable to be printed on conventional thermal printers.
• the color of the printing image is violet-black.
• the coating color A2 was manufactured in a dispersing unit by adding nitrocellulose E400, EDS-W(N), zinc stearate and lauryl gallate to acetone. The mixture was dispersed until a homogeneous dispersion was obtained.
• the composition of A2 is given in table 6.
• the coating composition A2 was applied to a PE film.
• the coating weight is 6 g/m 2 .
• the coating colors B2 to B4 were manufactured in a dispersing unit. The mixture was dispersed until a homogeneous dispersion was obtained.
• the composition of B2 to B4 is given in table 7.
• thermosensitive recording sheets are suitable to be printed on conventional thermal printers.
• the color of the printing image is violet-black.
• the coating color A3 was manufactured in a dispersing unit by adding nitrocellulose E400, EDS-W(N), zinc stearate and octyl gallate to acetone. The mixture was dispersed until a homogeneous dispersion was obtained.
• the composition of A3 is given in table 8.
• the coating color Z1 was manufactured in a dispersing unit by adding nitrocellulose E400, EDS-W(N), zinc stearate and octyl gallate to acetone. The mixture was dispersed until a homogeneous dispersion was obtained.
• the composition of Z1 is given in table 9.
• the coating composition A3 is applied to a PE film having a coating weight of 5 g/m 2 .
• the coating composition Z1 is applied to the first coating having as an intermediate coating a coating weight of 2 g/m 2 .
• the coating composition B3 (example 2) is applied to said intermediate coating having a coating weight of 6 g/m 2 .
• the obtained thermosensitive recording sheet is suitable to be printed on conventional thermal printers. The color of the printing image is violet-black.
• the coating composition A3 (example 4) is applied to a PE film having a coating weight of 5 g/m 2 .
• Setalux 6774 polyacrylate dispersion, Akzo Resins
• the coating composition B2 (example 3) is applied to said intermediate coating having a coating weight of 7 g/m 2 .
• the obtained thermosensitive recording sheet is suitable to be printed on conventional thermal printers. The color of the printing image is violet-black.
• thermosensitive recording sheet of the present invention is conforming to ⁇ 35 of the German "Lebensstoff- und forszurent Surprise", EN 1186 and EN 13130.
• the amount of compounds migrating from said recording sheet to foodstuff is admissible for articles having direct contact with foodstuff.
• the amount of volatile isomers, isocyanates, butadiene and remaining solvent in the recording sheet of the present invention is conforming to said regulation.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Theoretical Computer Science (AREA)
• Heat Sensitive Colour Forming Recording (AREA)

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Cited By (7)

Citations (9)

• 2002
  • 2002-07-17 EP EP02015885A patent/EP1382459A1/de not_active Withdrawn

Patent Citations (9)

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