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
  • B41M5/337—Additives; Binders
  • B41M5/3375—Non-macromolecular compounds
• • 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
  • B41M5/3336—Sulfur compounds, e.g. sulfones, sulfides, sulfonamides

Definitions

• the invention relates to a heat-sensitive recording sheet which is suitable for clear, intensive recordings at high speed and has a superior shelf life.
• a heat sensitive recording sheet is generally made by applying to the surface of a support such as paper, film, etc. a coating composition which is obtained by finely grinding and dispersing a colorless chromogenic substance and a color developing material, e.g. such as a phenolic substance, mixing the dispersions obtained together and adding a binder, filler, sensitizer, lubricant and other auxiliaries.
• a coating composition which is obtained by finely grinding and dispersing a colorless chromogenic substance and a color developing material, e.g. such as a phenolic substance, mixing the dispersions obtained together and adding a binder, filler, sensitizer, lubricant and other auxiliaries.
• the coating Due to the effect of heat or heat, the coating is instantly chemically converted to form a color. Depending on the choice of specific, colorless, chromogenic substances, various clear colors can be obtained.
• Bisphenol A 4,4'-isopropylidenediphenol
• the heat-sensitive recording sheets using p-hydroxybenzoic acid benzyl ester as a color developing agent have the disadvantages in terms of the stability of the image that the density of the image formed when the heat is applied decreases with the lapse of time, and that the p-hydroxybenzoic acid benzyl ester melted when the heat is applied decreases with that Recrystallized over time, forming white crystals.
• the invention has for its object to provide a heat-sensitive recording sheet which has a superior stability of the image (ie a stable recording image when stored for a long time), in particular in which neither discoloration of the image takes place under high atmospheric humidity, high temperature etc. nor discoloration of the background .
• the heat-sensitive recording paper according to the invention contains both 4-isopropyl-4'-hydroxydiphenylsulfone of the following formula (I) as an organic color developing agent in the color formation layer and also at least one compound from the group of substances of the following general formulas (11 ) or (III) contains as a sensitizer.
• the present invention thus relates to a heat-sensitive recording sheet with a color-forming layer which contains a basic colorless or pale-colored chromogenic dye and an organic color developing agent which is characterized in that the color forming layer is an organic color developing agent 4-isopropoxy-4'-hydroxy-diphenyl sulfone of the following Contains formula (I) and as a sensitizer at least one substance which is selected from the group of substances of the general formulas (11) and (III) below: wherein A represents an H or halogen atom, an NO 2 , lower alkyl, lower alkoxy or hydroxyl group; I represents an integer from 1 to 5; and m represents an integer from 0 to 3.
• the lower alkyl or lower alkoxy group (A) usually has 1 to 5 carbon atoms.
• lower alkyl groups are the methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl and tert-butyl group.
• lower alkoxy groups are the methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy and tert-butoxy groups.
• the 4-isopropoxy-4'-hydroxydiphenylsulfone as an organic color developing agent according to the invention has a melting point of 129-130 ° C.
• a known sensitizer such as stearic acid amide, benzyl p-benzyloxybenzoate, dibenzyl terephthalate, di-p-tolyl carbonate, etc.
• the reason for this can be attributed to the fact that the 4-isopropoxy-4'-hydroxydiphenylsulfone as a color developing agent has a high rate of solution diffusion and very high solubility in the sensitizer according to the invention, namely that the sensitizer of the general formulas (II) or (III) has great solvency for 4-isopropoxy-4'-hydroxydiphenyl sulfone.
• the sensitizer according to the invention also has a high solubility for a basic colorless dye.
• sensitizers according to the invention of the general formulas (II) and (III) are:
• the addition amount for the sensitizer according to the invention of the general formulas (11) or (III) is preferably 10-100 percent by weight, based on the 4-isopropoxy-4'-hydroxydiphenyl sulfone as organic color developing agent. With an addition of sensitizer of less than 10 percent by weight, the effect is small, but with an addition of more than 100 percent by weight, the image density is reduced because the organic color developing agent is diluted because of the large amount of sensitizer.
• the above-mentioned organic color developing agent, the above-mentioned basic colorless dye and the sensitizer are mixed by means of a grinder, e.g. a ball mill, grinder, sand grinder, etc. or ground to a particle size of several microns or smaller using a suitable emulsifying machine.
• a grinder e.g. a ball mill, grinder, sand grinder, etc. or ground to a particle size of several microns or smaller using a suitable emulsifying machine.
• additives are added, depending on the intended use, in order to produce the coating composition.
• the additives that can be used according to the invention are e.g. B.
• 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, aluminum hydroxide, etc .
• Release agents such as metal salts of fatty acids
• Lubricants such as waxes
• waterproofing agents such as glyoxal, etc .
• Dispersing agents, anti-foaming agents, mottoling-preventing agents for example fatty acid amide, e
• the kind and the amount of the organic color developing agent, the basic colorless dye, the sensitizer and the other components, which are determined depending on the desired effect and suitability for recording purposes, are not particularly limited. It is generally advantageous to use 3 to 12 parts by weight of 4-isopropoxy-4'-hydroxydiphenyl sulfone as a color developing agent, 3 to 12 parts by weight of sensitizer and 1 to 20 parts by weight of filler based on 1 part by weight of the basic colorless dye, and 10 to 25 parts by weight of binder, based on the total substance content, to be used.
• Parts is used as an abbreviation for parts by weight.
• the heat-sensitive recording sheet was produced according to Example 1, but without using solution C. The result is summarized in Table 1.
• Solution D (dispersion of the sensitizer)
• Each sensitizer in Table 1 4 parts of 10% solution of polyvinyl alcohol 5 parts of water 3 parts
• the heat-sensitive recording sheets were produced according to Example 1, but with solution D instead of solution C.
• the heat-sensitive recording sheet was produced according to Example 3, but without using solution C.
• the result is summarized in Table 1.
• the heat-sensitive recording sheet of the present invention in which both 4-isopropoxy-4'-hydroxydiphenylsulfone as a color developing agent and p-benzylbiphenyl are added to the color formation layer gives higher dynamic image density, superior durability of the undyed part and an improved durability of the recording image.

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)

Applications Claiming Priority (2)

Publications (3)

Family

ID=15994981

Family Applications (1)

Country Status (4)

Families Citing this family (12)

Family Cites Families (6)

• 1984
  • 1984-08-23 JP JP59175374A patent/JPS6153084A/ja active Granted
• 1985
  • 1985-08-06 US US06/763,045 patent/US4644375A/en not_active Expired - Lifetime
  • 1985-08-20 DE DE8585110455T patent/DE3574117D1/de not_active Expired
  • 1985-08-20 EP EP85110455A patent/EP0173232B1/de not_active Expired

Also Published As

Similar Documents

Legal Events