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
  • B41M5/32—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

Definitions

• the invention relates to a heat-sensitive recording sheet which has a superior stability of the color image and the whiteness of the background against hair oil, grease, oil, etc.
• a heat-sensitive recording sheet using a heat color reaction between a basic colorless or lightly colored chromogenic dye and an organic color developing agent such as a phenolic substance or an organic acid is disclosed in Japanese Patent Publication Nos. 4160/1968 and 14039 / 1970, and described in Japanese Patent Laid-Open No. 27736/1973. It has many practical uses.
• a heat-sensitive recording sheet is generally prepared by applying a coating composition to the surface of the support such as paper, film, etc., which can be finely divided by individually grinding and dispersing a colorless chromogenic dye and a color developing material such as phenolic substances into fine particles dispersions obtained and by adding a binder, filler, sensitizer, lubricant and other auxiliaries.
• the oily materials are the color-forming layer consisting of a basic colorless chromogenic dye of fine particles and an organic color developing agent of fine particles, or the color-forming reaction product which is made of a basic colorless chromogenic Dye and one. organic color developing agent is formed, partially dissolve or destabilize.
• EP-A-58 345 describes a heat-sensitive recording sheet which, in addition to a basic colorless or slightly colored chromogenic dye and an organic color developing agent, contains dimethyl terephthalate in the color formation layer.
• the dimethyl terephthalate serves to stabilize the recording image against the action of oily materials such as hair oil, sweat, etc.
• the invention has for its object to provide a heat-sensitive recording sheet in which the recording image is very stable against the action of oily materials.
• R 1 is preferably a CH 3 , C 2 H 5 , C 3 H 7 ' iso-C 3 H 7 , tert-C 4 H 9 , C 5 H 11 or C 6 H, 3 group; when R 2 , R 3 and / or R 4 represent an alkyl group, this is preferably a methyl or ethyl group. If halogen substituents are mentioned here, these are preferably F, CI and Br atoms, in particular CI atoms.
• the amount and kind of the color developing agent used in the present invention are not particularly limited, but the effects of this invention are remarkable when monophenolic 4-hydroxyphenyl compounds and / or phthalic acid monoesters are used as the color developing agent since they are essential for improving the quality of the heat-sensitive recording sheets contribute; e.g. B. clear recording with high image density, no adhesion of residues to the thermal head, no sticking of the heat-sensitive recording sheet to the thermal head, superior recording suitability, less color formation of the background over time, etc.
• Examples of monophenolic 4-hydroxyphenyl compounds are 4-hydroxybenzoic acid esters, for example 4-hydroxybenzoic acid propyl ester, 4-hydroxybenzoic acid isopropyl ester, 4-hydroxybenzoic acid butyl ester, 4-hydroxybenzoic acid isobutyl ester, 4-hydroxybenzoic acid benzyl ester, 4-hydroxybenzyl ester, etc.
• 4-hydroxyphthalic diesters such as dimethyl 4-hydroxyphthalate, diisopropyl 4-hydroxy phthalate, dibenzyl 4-hydroxy phthalate, di-4-hydroxy phthalate, etc .; 4-hydroxyacetophenone; p-phenylphenol; Benzyl-4-hydroxyphenylacetate; p-benzylphenol; 4-hydroxyphenyl-4'-n-sulfone, 4-hydroxyphenyl-4'-n-butyloxyphenylsulfone, 4-hydroxyphenyl-4'-n-hexyloxy-phenylsulfone, 4-hydroxyphenyl-4'-n-octyloxyphenylsulfone, 4-hydroxyphenyl- 4'-n-decyloxyphene sulfone, 4-hydroxyphenyl-4'-n-dodecyloxyphenyl sulfone, 4-hydroxyphenyl-4'-benzyloxyphenyl sulfone, 4-hydroxyphenyl-4'-p-isoprop
• phthalic acid monoesters are phthalic acid monophenyl ester, phthalic acid monobenzyl ester, phthalic acid monocyclohexyl ester, phthalic acid monomethylphenyl ester, phthalic acid monoethylphenyl ester, phthalic acid monoalkylbenzyl ester, phthalic acid monohalobenzyl ester, and phthalic acid mono-ester, phthalic acid mononate.
• bisphenol compounds examples include 4,4'-isopropylidenediphenol (bisphenol A), 4,4 '(1-methyl-n-hexylidene) diphenol, 4,4'-cyclohexylidenediphenol, 4,4'-thiobis-4-tert-butyl -3-methylphenol and the like. These color developing agents used in combination are unsatisfactory in stability against oily materials.
• colorless or slightly colored chromogenic dyes are useful for the invention and are not particularly limited.
• metal salts of phthalic acid monoester of the general formula I are metal salts of Phthalcicremonophenylester, Phthalklaremonobenzylester, Phthal skilletremonocyclohexylester, Phthal skilletremonomethylphenylester, Phthal skilletremonophenylester, Phthal skilletremonoalkylbenzylester, Phthal skilletremonohalogenbenzylester, Phthal skilletremonoalkoxybenzylester, 4-Methylphthalklaremonobenzylester, 3-Methylphthalklaremonobenzylester, 5-Methylphthalklaremonobenzylester, 4-Methylphthal Acidmonocyclohexylester, 3-Methylphthal Acidmonocyclohexylester, 5-methyl phthalic acid monocyclohexyl ester and the like, preferably metal salts of phthalic acid monobenzyl ester and phthalic acid monocyclohexy
• B polyvalent metals such as zinc, calcium, magnesium, barium and lead. preferably zinc, calcium and magnesium indicated.
• These stabilizers can be used individually or in a mixture.
• the above-mentioned organic color developing agent, the above-mentioned organic colorless chromogenic dye and the metal salt derivative of the phthalic acid monoester are ground to a particle size of several microns or smaller by means of a grinder such as a ball mill, grinder, sand grinder, etc. or by means of a suitable emulsifying machine.
• a grinder such as a ball mill, grinder, sand grinder, etc. or by means of a suitable emulsifying machine.
• additives are added to this, depending on the intended use, in order to produce the coating color.
• the additives that can be used according to the invention are e.g. B. the following: binders such as polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, starch, styrene-maleic anhydride copolymers, vinyl acetate-maleic anhydride copolymers, styrene-butadiene copolymers, etc.; inorganic or organic fillers such as kaolin, baked kaolin, diatomaceous earth, talc, titanium dioxide, calcium carbonate, magnesium carbonate, aluminum hydroxide, etc.; Release agents such as metal salts of fatty acids; Lubricants such as waxes; UV absorbers of the benzophenone and triazole series; waterproofing agents such as glyoxal etc.; Dispersing agents, anti-foaming agents, etc.
• the desired heat-sensitive sheet is obtained by
• the amount of the metal salts of the phthalic acid monoester according to the invention and the type and the amount of the other constituents which are determined depending on the desired effect and the suitability for recording purposes are not particularly limited.
• Image density of the non-recorded part is measured with a Macbeth density meter.
• the image density of the unrecorded part is changed from 60 ° C and 45% relative humidity and then measured with a Macbeth density meter.
• the examples of the present invention in which metal salts of phthalic acid monoesters were used as a stabilizer, gave a very good recording image even after standing for 7 days after being contaminated with castor oil. H. good stabilization was achieved, which is expressed in a residual image density of more than 70%.
• the examples according to the invention, in which the zinc salt is used as the metal salt of the stabilizers according to the invention have a high residual image density even when contaminated with oil.
• solution B in which the same amount of 4-hydroxyphthalic acid monobenzyl ester was used instead of the 4-hydroxybenzoic acid benzyl ester in solution B (color developing agent dispersion) of example 1, was prepared and mixed with a calcium carbonate dispersion and solutions A and C in the weight ratio of Table 3 mixed.
• the stabilizers according to the invention have superior effects even when using phthalic acid monobenzyl ester as color developing agent.
• the zinc salts of the phthalic acid monoesters have a superior stability of the recording image, in particular a considerably superior stability of the recording image when using 4-hydroxybenzoic acid ester or phthalic acid monoester as color developing agent.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Heat Sensitive Colour Forming Recording (AREA)
• Color Printing (AREA)

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• 1983
  • 1983-08-24 JP JP58153083A patent/JPS6046293A/ja active Granted
• 1984
  • 1984-08-21 US US06/642,788 patent/US4590500A/en not_active Expired - Lifetime
  • 1984-08-23 DE DE8484110091T patent/DE3468196D1/de not_active Expired
  • 1984-08-23 EP EP84110091A patent/EP0137982B1/de not_active Expired

Patent Citations (1)

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