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
• • 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
  • B41M5/423—Intermediate, backcoat, or covering layers characterised by non-macromolecular compounds, e.g. waxes
• • 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
  • B41M5/426—Intermediate, backcoat, or covering layers characterised by inorganic compounds, e.g. metals, metal salts, metal complexes
• • 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
  • B41M5/44—Intermediate, backcoat, or covering layers characterised by the macromolecular compounds

Definitions

• This invention relates to a heat-sensitive recording material useful for labels, which is superior in image-retainability and stably produced without blocking, further in which the developed color images have a high PCS value when the back of the base sheet is printed.
• the application as a label has been increased with the enlargement of the POS (point of sales) systematization in a retail store and the like.
• an adhesive layer is formed on the back of the base sheet and a release sheet base material is applied to the adhesive layer.
• an adhesive agent of the adhesive layer there are generally used rubber type or acrylic type adhesive agents.
• heat-sensitive recording materials for label in which a rubber type adhesive agent is used are sticking on a wrapping film containing a plasicizer, the plasticizer is easily migrated into the adhesive layer.
• the base sheet is paper, the plasticizer is penetrated into paper and further arrived in the heat-sensitive recording layer. As a result of it, the image-retainability of the heat-sensitive recording materials is very lowered.
• a back-coating layer mainly comprising a water-soluble polymer has been applied as described Japanese Laid-Open Utility Model Publication No.140461 of 1981.
• the coating layer is inferior in water-resistance, when the back-coating layer is formed, a so-called "blocking phenomena" which is a phenomena of adhering the back-coating layer with the heat-sensitive recording layer in the winding step occurs to make the commercial value of a heat-sensitive recording material very low.
• a method for preventing the blocking phenomena there has been disclosed in Japanese Laid-Open Patent Publication No.32081 of 1987 that a colloidal silica is comprised in the back-coating layer.
• a substantial plasticizer resistance can not be obtained.
• the heat-sensitive recording material according to the present invention has a heat-sensitive recording layer which comprises a colorless or pale colored basic chromogenic material and a color developer developing a color by contacting with the chromogenic material on a surface of the base sheet, and an adhesive layer on the back of the base sheet.
• a coating layer mainly comprising inorganic and/or organic pigments together with a binder is formed, and K & N ink absorption of the coating layer is adjusted to from 5.0 gIm 2 to 10.0 glm 2 .
• the most important features of the present invention are the formation of a coating layer which mainly comprises inorganic and/or organic pigments together with a binder on the back or both surfaces of the base sheet, and the adjustment of K & N ink absorption of the coating layer to from 5.0 g/m 2 to 10.0 g/m 2 , preferably to from 5.0 g /m 2 to 7.0 g/ m 2.
• the plasticizer resistance of the heat-sensitive recording material becomes very bad.
• the K & N ink used in the present invention is a colored ink only used for measuring ink absorption of paper.
• the measuring method generally comprises the steps of coating the K & N ink in excess on the whole surface of a coated paper, allowing it to stand for 2 minutes at the room temperature, substantially wiping the excess amount of the ink from the surface with a gauze, waste or the like, and then examining the variation of the whiteness as a measure of the ink-absorption of paper.
• the K & N ink absorption in the present invention is defined as an absorbed ink-amount per square meter which is obtained by measuring the ink amount absorped in paper after the above treatment.
• the K & N ink absorption useful in the present invention is 5.0 glm 2 to 10.Og/m 2 , preferably 6.0 glm 2 to 10.Og/m 2 and the most preferably 6.0 g/m 2 to 7.0g/m 2 .
• the heat-sensitive recording materials according to the present invention are not obtained by merely using paper in which the plasticizer resistance is improved by making the K & N ink absorption lover. It is necessary in the present invention to add pigments in the coating layer applied on the back or both surfaces of the base sheet to prevent a lowering of the PCS value depending on a remarkable lowering of the K & N ink absorption and to prevent the occurrence of a blocking phenomena. Further, as the pigments added in the coating layer, there are preferably used, in consideration of the K & N ink absorption, those having an oil absorption of less than 50 ml/100 g, more preferably 10 to 40 mi/100 g, which is measured by JIS K-5101.
• pigments there are exemplified inorganic pigments such as kaolin, day, calcium carbonate, aluminum hydroxide, silicon oxide, calcined clay and the like ; and organic pigments such as styrene microballs, polyamide powder, polyethylene powder, urea-formaldehyde resin filler, raw starch particles and the like.
• inorganic pigments such as kaolin, day, calcium carbonate, aluminum hydroxide, silicon oxide, calcined clay and the like
• organic pigments such as styrene microballs, polyamide powder, polyethylene powder, urea-formaldehyde resin filler, raw starch particles and the like.
• the other pigments may be used. Those pigments may be used either solely or in combination.
• the binders contained in the coating layer are not particularly limited. Among them, there are included proteins such as casein and the like ; starches such as cationic starch, phosphoric esterified starch, oxidized starch and the like ; cellulose derivatives such as hydroxyethylcellulose, carboxymethylcellulose and the like ; gum arabic, polyvinyl alcohol, carboxy-group modified polyvinyl alcohol, acetoacetyl-group modified polyvinyl alcohol, salts of diisobutyrenemaleic anhydride copolymer, salts of styrene-maleic anhydride copolymer, urea resins, melamine resins, amide resins and the like.
• proteins such as casein and the like ; starches such as cationic starch, phosphoric esterified starch, oxidized starch and the like ; cellulose derivatives such as hydroxyethylcellulose, carboxymethylcellulose and the like ; gum arabic, polyvinyl alcohol,
• the preferable binders are those having a glass transition temperature of 30 °C or less, particularly from -30 °C to 0 °C, such as latexes of conjugated diene polymers, e.g., styrene-butadiene copolymer, methylmethacrylate-butadiene copolymer and the like ; acrylic polymers, e.g., homopolymer or copolymer of acrylic esters and/or methacrylic esters ; vinyl polymers, e.g., ethylene-vinyl acetate copolymer and the like.
• conjugated diene polymers e.g., styrene-butadiene copolymer, methylmethacrylate-butadiene copolymer and the like
• acrylic polymers e.g., homopolymer or copolymer of acrylic esters and/or methacrylic esters
• vinyl polymers e.g., ethylene-vinyl
• the binders are preferably used in an amount of 8 to 40 % by weight, more preferably 10 to 30 % by weight with respect to the total solid amount of the coating composition.
• the amount is more than 40 %, the drying speed of the ink (namely, ink set) is inferior, and when the amount is less than 8 %, the surface strength is lowered.
• the coating composition may include various kinds of additives such as dispersing agents, e.g., sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium salt of lauryl alcohol sulfate, metal salts of fatty acids and the like ; lubricants, e.g., zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, ester wax and the like ; ultraviolet ray absorbers, e.g., benzophenone compounds and the like ; antifoaming agents ; fluorescent dyes; coloring dyes and the like.
• dispersing agents e.g., sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium salt of lauryl alcohol sulfate, metal salts of fatty acids and the like ; lubricants, e.g., zinc stearate, calcium stearate,
• the coating composition is applied on the base sheet with use of such as an air-knife coater, blade coater, bar coater, roll coater, gravure coater, curtain coater or the like, and dried.
• the amount of the applied coating composition is not also particularly limited, but it is generally controlled within the range of 3 to 30 g/m 2 , preferably 5 to 15 g/m 2 on dry basis.
• the coating layer which has a K&N ink absorption of 5.0 g/m 2 to 10.0 glm 2 by controlling the used materials, mixed ratio, coated amount and the like.
• triallylmethane compounds such as 3,3- bis(p-dimethylaminophenyl)-6-dimethylaminophthalide, 3,3-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl)-3-(1,2-dimethylindole-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(2-methylindole-3-yl)-phthalide, 3,3-bis(1,2-dimethylindole-3-yl)-5-dimethylaminophthalide, 3,3-bis(1,2-dimethylindole-3-ylr6-dimethylaminophthalide, 3,3-bis(9-ethylcarbazole-3-yl)-6-dimethylaminophthalide, 3,3-bis(9-ethylcarbazole-3-yl)-6-dimethylaminophthalide, 3,3-bis(9-eth
• inorganic acidic compounds such as activated clay, attapulgite, colloidal silica, aluminum silicate and the like ; organic acidic compounds such as phenolic compounds, e.g., 4-tert-butylphenol, 4-hydroxydiphenoxide, a - naphthol, ⁇ -naphthol, 4-hydroxyacetophenol, 4-tert-octylcatechol,2,2'-dihydroxydiphenol, 4,4'-isopropylide- nebis(2-tert-butylphenol), 4,4'-sec-butylidenediphenol, 4-phenylphenol, 4,4'-isopropylidenediphenol, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 2,2'-methylenebis(4-chlorophenol), hydroquinone, 4,
• the used ratio of the basic chromogenic materials and the color developer may be suitably selected depending on the kind of the basic chromogenic material and the color developer, and accordingly is not particularly limited.
• the used amount of the color developer is generally within the range of 1 to 50 parts by weight, preferably 2 to 10 parts by weight, per one part by weight of the basic chromogenic materials.
• the coating composition comprising those above materials is generally prepared by dispersing simultaneously or separately the chromogenic material and the color developer in water as the dispersion medium with use of a mixer or pulverizer such as ball mill, attritor, sand mill or the like.
• binders contained in the coating composition there are exemplified starches, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, gum arabic, polyvinyl alcohol, carboxyl-group modified polyvinyl alcohol, acetoacetyl-group modified polyvinyl alcohol, salts of diisobutylene-maleic anhydride copolymer, salts of styrene-maleic anhydride copolymer, salts of ethylene-acrylic acid copolymer, salts of styrene-acrylic acid copolymer, styrenebutadiene copolymer emulsions, urea resin, melamine resin, amide resin and the like.
• the coating composition may include various kinds of additives such as dispersing agents, e.g., sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium salt of lauryl alcohol sulfate, metal salts of fatty acids and the like ; zinc stearate or calcium stearate ; waxes, e.g., polyethylene wax, carnauba wax, paraffin wax, ester wax and the like ; ultraviolet ray absorbers, e.g., benzophenone compounds and the like ; antifoaming agents ; fluorescent dyes ; coloring dyes and the like.
• dispersing agents e.g., sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium salt of lauryl alcohol sulfate, metal salts of fatty acids and the like ; zinc stearate or calcium stearate ; waxes, e.g.
• pigments may be added.
• pigments there are included such as inorganic pigments, e.g., kaolin, clay, calcium carbonate, calcined clay, calcined kaolin, titanium dioxide, diatom earth, fire-grain anhydrous silica, activated clay and the like; and organic pigments, e.g., styrene microball, Nylon powder, polyethylene powder, urea-formaldehyde resin filler, raw starch powder and the like.
• inorganic pigments e.g., kaolin, clay, calcium carbonate, calcined clay, calcined kaolin, titanium dioxide, diatom earth, fire-grain anhydrous silica, activated clay and the like
• organic pigments e.g., styrene microball, Nylon powder, polyethylene powder, urea-formaldehyde resin filler, raw starch powder and the like.
• Sensitizers may be used simultaneously, if necessary.
• fatty acid amides such as caproic acid amide, capric acid amide, stearic acid amide, oleic acid amide, erucic acid amide, linolic acid amide, linoleic acid amide, N-mehtylstearic acid amide, benzanilide, linolic acid anilide, N-ethylcap- ric acid amide, N-butyllaulic acid amide, N-octadecyl acetamide, N-olein acetamide, N-oleyl benzoamide, N-stearyl cyclohexylamide, polyethyleneglycol, 1-benzyloxynaphthalene, 2-benzyloxynaphthalene, phenyl 1-hydroxynaphthoate, 1,2-diphenoxyethane, 1,4-diphenoxybutane, 1,2-
• the usage amount of the sensitizer is not particularly limited, however, it is generally preferable to adjust the amount within the range of not more than 4 parts by weight per one part by weight of the color developer.
• methods for forming the recording layer are not particularly limited. It may be formed by coating the coating composition on a base sheet with a coating method such as air-knife coating, rod-blade coating, pure-blade coating, short dwell coating, and drying it.
• the amount of the applied coating composition is particularly limited, but generally adjusted within the range of 2 to 12 glm 2 , preferably 3 to 10 g/m 2 .
• a protective layer is preferably applied.
• a water-soluble or water-dispersible polymer used for forming the protective layer there are exemplified polyvinyl alcohol, carboxyl-group modified polyvinyl alcohol, acetoacetyl-group modified polyvinyl alcohol, silicon-containing modified polyvinyl alcohol, hydroxyehtylcellulose, methylcellulose, carboxymentylcellulose, starch and the derivatives, casein, sodium alginate, polyvinyl pyrrolidone, polyacrylic amide, salts of styrene-maleic anhydride copolymer, polyurethane resin, urea resin, melamine resin, polyamide resin, epichlorohydri- nated polyamide resin, sutyrene-butadiene copolymer emulsion, styrene-acrylic acid ester type emulsion, acrylic acid ester type emulsion and the like.
• the polymers may be used
• acetoacetyl-group modified polyvinyl alcohol and silicon-containing modified polyvinyl alcohol are particularly preferred because of forming a strong resin film.
• pigments may be added in the protective layer.
• the pigments there are exemplified inorganic pigments such as calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide, silicon dioxide, aluminum hydroxide, barium sulfate, zinc sulfate, talc, kaolin, clay, calcined kaolin, calcined clay, coloidal silica and the like ; organic pigments such as styrene microballs, Nylon powder, polyethylene powder, urea-formaldehyde resin filler, raw starch powder and the like.
• the usage amount of the pigments is preferable to be adjusted within the range of 20 to 500 parts by weight per 100 parts by weight of the binders.
• lubricants e.g., zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax and ester wax ; surface-active agents, e.g., sodium dioctylsulfosuccinate ; anti-foaming agent and the like.
• a hardener such as glyoxal, boric acid, dialdehyde starch, epoxy type compounds and the like.
• the coated amount of the composition is generally controlled within the range of 1 to 20 g/m 2 , preferably 2 to 10 g/m 2 on dry basis, because the image-retainability is not substantially improved and a thermal head sticking easily occurs if the coated amount is less than 1 g/m 2 , and on the other hand the recording sensitivity of the heat-sensitive recording material is lowered if the coated amount is more than 20 g/m 2 .
• the heat-sensitive recording material may be added various kinds of well-known technique for producing the heat-sensitive recording material, such as formation of an under-coating layer between the heat-sensitive layer and the base sheet having a specific coating layer of the present invention.
• the base sheet papers such as paper and synthetic paper are mainly used.
• composition was coated in the weight of an amount of 10 g/m 2 on dry basis on a surface of a base sheet of 40 g/m 2 and dried to form a back-coating layer on a surface of the base sheet.
• composition was pulverized by a sand mill, and the pulverization was continued until an average particle size of 3 ⁇ m.
• composition was pulverized by a sand mill, and the pulverization was continued until an average particle size of 3 ⁇ m.
• composition was pulverized by a sand mill, and the pulverization was continued until an average particle size of 3 ⁇ m.
• the following composition was mixed with stirring to prepare a coating composition.
• the coating composition was coated in the weight of an amount of 6 g/m 2 on dry basis on the other surface of the base sheet having the back-coating layer, and dried to form a recording layer on the base sheet.
• the following composition was mixed with stirring to prepare a protective coating composition.
• the coating composition was coated in the weight of an amount of 5 g/m 2 on dry basis on the recording layer, dried and calendered to obtain a heat-sensitive recording material having a protective layer on the recording layer.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that vinyl chloride-ethylene copolymer emulsion (glass transition temperature: 20 °C , solid amount : 50 %) was used instead of styrene-butadiene copolymer emulsion to prepare the coating composition in the step 1.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that vinyl acetate-ethylene-vinyl chloride copolymer emulsion (glass transition temperature : 0°C , solid amount : 50 %) was used instead of styrene-butadiene copolymer emulsion to prepare the coating composition in the step 1.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that acrylic acid ester copolymer emulsion (glass transition temperature : 15°C, solid amount : 50 %) was used instead of styrene-butadiene copolymer emulsion to prepare the coating composition in the step 1.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that kaolin (oil absorption : 30 ml/100g) was used instead of calcium carbonate to prepare the coating composition in the step 1.
• kaolin oil absorption : 30 ml/100g
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that the following coating composition was used as the coating composition of the step 1;
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that aluminum hydroxide (oil absorption 35 m1/100g) was used instead of calcium carbonate to prepare the coating composition in the step 1.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that the coating composition in the step 1 was coated in the weight of an amount of 10 g/m 2 on dry basis on each of the back and front surfaces of the base sheet.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that styrene- butadiene copolymer emulsion (glass transition temperature : 33°C, solid amount : 50 %) was used instead of styrene-butadiene copolymer emulsion (glass transition temperature : -6°C , solid amount : 50 %) to prepare the coating composition in the step 1.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that vinyl acetate-ethylene-vinyl chloride copolymer emulsion (glass transition temperature : 50 °C) , solid amount : 50 %) was used instead of styrene-butadiene copolymer emulsion (glass transition temperature : -6 °C , solid amount : 50 %) to prepare the coating composition in the step 1.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that acrylic acid ester copolymer emulsion (glass transition temperature : 45 °C , solid amount : 50 %) was used instead of styrene-butadiene copolymer emulsion (glass transition temperature : -6°C , solid amount : 50%) to prepare the coating composition in the step 1.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that the following composition was used as the coating composition in the step 1;
• Heat-sensitive recording material was obtained in the same manner as in Example 1 except that the following composition was used as the coating composition in the step 1;
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that the following composition was used as the coating composition in the step 1;
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that the following composition was used as the coating composition in the step 1 ; Comparative Example 1
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that calcined kaolin (oil absorption : 80 ml/100g) was used instead of calcium carbonate to prepare the coating composition in the step 1.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that calcined talc (oil absorption : 80 ml/100g) was used instead of calcium carbonate to prepare the coating composition in the step 1.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that 10 % aqueous solution of aceto-acetylated polyvinyl alcohol was used instead of the coating composition in the step 1.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that the mixture of styrene-methyl acrylate copolymer emulsion (solid amount :45 %) and 30 % aqueous dispersion of coloidal silica in the ratio of 2 : 1 was used instead of the coating composition in the step 1.
• a heat-sensitive recording material was obtained in the same manner as in Example 1 except that a styrene-butadiene copolymer emulsion (glass transition temperature : -6 °C , solid amount : 50 %) was used instead of the coating composition in the step 1.
• K & N ink is coated in excess on the back surface of a heat-sensitive recording material, and allowed to stand for 2 minutes at the room temperature. Then the excess ink is substantially wiped with a gauze and immediately the heat-sensitive recording material is weighed to calculate the absorbed amount of the ink (g/m 2 ).
• the heat-sensitive recording material is pressed by a hot plate heated at 120°C for 5 seconds under 4 kglcm 2 to record color images and a rubber binder (ECOMELT L-302 manufactured by ECOMELT AG) is coated on the back surface of the recorded material in the weight of an amount of 20 gIm 2 .
• a polyvinylidene chloride film manufactured by Mitsui Toatsu Chemicals, Inc. is wrapped threefold around a polypropylene pipe having a diameter of 40mm.
• the recorded material is put on the outer surface in the manner as the color images are exposed outward and further a polyethylene film which does not contain a plasticizer is wrapped threefold around the recorded material.
• the resultant material is allowed to stand at 40 °C for 24 hours, and then the image density of the color images is measured.
• Plasticizer resistance is evaluated by the discoloration degree of the color images as follows ;
• a black ink (New Chanpion F Gloss manufactuered by Dai Nihon Ink Chemical Corp.) is printed on the back surface of a heat-sensitive recording material by RI Printing Tester.
• the heat-sensitive recording material is pressed by a hot plate heated at 120 °C for 5 seconds under 4 kglcm 2 to record color images.
• the color density of the recorded images and the background is measured by Macbeth densitometer RD-100R manufactured by Macbeth Corp.
• PCS value is calculated by the following equation. [Ink set property]
• a black ink (New Chanpion F Gloss manufactured by Dai Nihon Ink Chemical Corp.) is printed on the back surface of a heat-sensitive recording material by RI Printing Tester and immediately the back surface without printed images is put on the printed back surface and pressed by a roller several times.
• the ink transfer is evaluated with naked eyes as follows ;
• a test ink for paper (Printing Ink SD Super Deluxe 50 Beni manufactured by Toka Sikiso Kabushiki Kaisha) is printed on the back surface of a heat-sensitive recording material by RI Printing Tester and the state of picking (surface-peeling off) is observed and evaluated as fol- lowes :
• each of the heat-sensitive recording materials according to the present invention is superior in both of plastisizer resistance and blocking resistance, and further indicates a high PCS value when a back-printing is applied.

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Citations (5)

• 1991
  • 1991-01-28 EP EP19910300612 patent/EP0440388A3/en not_active Withdrawn

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