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
• • 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
  • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
  • B41N1/00—Printing plates or foils; Materials therefor
  • B41N1/24—Stencils; Stencil materials; Carriers therefor
  • B41N1/242—Backing sheets; Top sheets; Intercalated sheets, e.g. cushion sheets; Release layers or coatings; Means to obtain a contrasting image, e.g. with a carbon sheet or coating
• • 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

• thermographically color-developable compositions useful in the preparation of heatsensitive copy sheets and heat-sensitive stencil sheets.
• heat-sensitive copy sheets refers to sheets coated with a composition which will develop a visible image corresponding to an original when exposed to the original in a manner to be described hereinafter.
• heat-sensitive stencil sheets refers to porous substrates coated with a heat-shrinkable thermoplastic film containing or in contact with a heat-sensitive color-developable composition, or such a porous substrate impregnated with an ink permeable resin. Stencil sheets are employed in the preparation of stencils such as are utilized in mimeographic printing.
• Typical heat-sensitive copy sheets comprise a thin paper or plastic support provided with a thermographically colordevelopable layer formed by coating the substrate with a composition containing at least two compounds capable of reacting at elevated temperature to form a colored product.
• Typical heat-sensitive stencil sheets are prepared by aflixing a thermoplastic film to a porous thin support or impregnating the support with an ink permeable composition. The method of preparing copy sheets and stencil sheets utilizing the compositions of this invention will be described in more detail hereinafter.
• At least one iron salt which is a ferrous or ferric salt of a higher aliphatic carboxylic acid having at least 10 carbon atoms
• Typical alkyl radicals include straight and branch chain radicals such as methyl, decyl, isopropyl, t-butyl, and the like.
• Typical aryl radicals include phenyl, tolyl, xylyl, biphenyl, naphthyl and similar radicals.
• Acyl radicals may suitably be selected from formyl, acetyl, propionyl, butyryl, valeryl, palmitoyl, stearoyl, oleoyl, oxalyl, malonyl, succinyl, benzoyl, toluoyl, salicyloyl, cinnamoyl, naphthoyl, phthaloyl, or furoyl.
• the iron salts are ferrous or ferric salts of higher aliphatic carboxylic acids.
• the preferred salts are derived from saturated and unsaturated acids containing from about 10 to 25 carbon atoms. Salts with a smaller number of carbon atoms while useful are generally not practical because of their offensive odor. Salts with more than 25 carbon atoms may similarly be employed but are generally not preferred since they are difficult to synthesize or to purchase commercially.
• Thiosemicarbazide derivatives have been similarly employed in the prior art.
• the semicarbazidcs utilized herein have a number of most unexpected advantages when compared to the prior art sulfur analogs.
• Perhaps the most significant advantage of the compositions of this invention is that their ability to form colored derivatives does not deteriorate with storage as is the case with compositions based on thiosemicarbazides.
• Ferrous and ferric salts of the saturated and unsaturated aliphatic carboxylic acids employed in the invention are readily prepared by reacting the selected soluble iron salt in an aqueous media with the acid.
• Iron salts of the following acids are typical of those which may be used: nundecyclic, lauric, myristic, palmitic, margaric, stearic, arachidic, behenic, lignoceric, oleic and linoleic.
• the semicarbazide derivative and iron salt utilized in this invention may appear in a variety of both wet and dry media. They may be dissolved or dispersed, for example, in a liquid vehicle or dispersed in a solid.
• the liquid may be simply one which serves as a vehicle by which the reactants are spread onto the substrate. It may be one which additionally contains a resinous substance serving as an adhesive or as the thermoplastic film to be perforated in the conversion of a stencil sheet to a stencil.
• the solid vehicle may be the dried adhesive on the substrate or it may be the plastic film of a stencil sheet or a. copy sheet.
• one reactant may be in a first liquid vehicle and the other reactant in a second liquid vehicle and that the two are not brought into reactive proximity until they are spread on the support.
• the vehicle whether solid or liquid is inert with respect to the reaction which takes place between the semicarbazide derivative and the iron salt.
• the vehicle will be referred to herein as an inert carrier.
• the weight ratio of iron salt of higher aliphatic carboxylic acid to semicarbazide derivative in an inert carrier with both copy sheets and stencil sheets is from about 1:0.1-2.
• the preferred ratio, especially for the preparation of stencil sheets, is 1:0.1-0.3.
• the weight of reactants on the substrate in copy sheets is from about 0.1-5 g./m. and the optimum amount is about 2 g./m.
• the amount of reactants is from about 0.13 g./m.
• the reaction by which the colored product is formed is effected at approximately the temperature at which either or both of the reactants melt.
• the colored products which form the images therefore normally are produced at a temperature of from about 50 C.-150 C.
• compositions of this invention it is possible to prepare copy sheets which are inexpensive, do not develop a cloudy appearance on storage and are substantially free from deterioration of color-developability during storage.
• the reactants can be selected to produce black, blue or brown color in striking contrast to the background support even though they are employed in small amounts.
• an iron salt of an aliphatic carboxylic acid and the semicarbzaide derivative are slowly mixed in a liquid carrier to form a solution or suspension which is then coated by any convenient method onto a substrate such as standard paper, parchment paper, sulfate paper, cellophane, or the like or a synthetic resin film, for example, cellulose acetate or polyethylene terephthalate, or on resin impregnated paper or cloth.
• a substrate such as standard paper, parchment paper, sulfate paper, cellophane, or the like or a synthetic resin film, for example, cellulose acetate or polyethylene terephthalate, or on resin impregnated paper or cloth.
• the carrier by means of which the reactants are bonded to the substrate may be any of a variety of such carriers normally employed with the prior art compositions and include, for example, ethyl cellulose, methyl cellulose, cellulose acetate and other cellulose derivatives, polyvinyl acetate and copolymers thereof, polyvinyl chloride and copolymers thereof, polyvinyl alcohol, polyvinyl butyral, polyamides, polystyrene and copolymers thereof, silicon resins, resins based on phenol and synthetic materials.
• the image is formed on the copy sheet by any of the usual procedures.
• the original is brought into contact with the copy sheet either on the side carrying the heat-sensitive materials or on the opposite side and the image is developed on the copy sheet by the application of infrared rays in accordance with standard practice.
• the image formed on the copy sheets of this invention is extremely stable especially at room temperature and does not discolor or fade appreciably when exposed to sun light. As a result no fixing step is required for the production of a permanent image.
• Heat-sensitive stencil sheets may be divided broadly into two categories. These are:
• Stencil sheets prepared by afiixing a thermoplastic film for example, a copolymer of vinyl and vinylidene chloride, which is about 7 thick to a thin porous support such as paper;
• Stencil sheets prepared by impregnating a thin porous material such as paper with an ink-permeable agent suitably a cellulose derivative such as ethyl cellulose, cellulose acetate-butyrate or cellulose acetate-propionate, polystyrene and copolymers thereof, polyvinyl chloride and copolymers thereof, polyacrylic and polymethacrylic esters and wood resin.
• an ink-permeable agent suitably a cellulose derivative such as ethyl cellulose, cellulose acetate-butyrate or cellulose acetate-propionate, polystyrene and copolymers thereof, polyvinyl chloride and copolymers thereof, polyacrylic and polymethacrylic esters and wood resin.
• stencil sheets of class (a) above are formed in accordance with this invention. These are:
• One method of forming stencil sheets of class (b) above is to disperse or dissolve both reactants into the same solvent which contains the ink-permeable layer forming agent before impregnation of the porous substrate. Another is to impregnate the porous substrate in the usual way and thereafter apply the reactants to the surface of the substrate in a liquid carrier which is then dried.
• porous substrate for use in the preparation of sten cil sheets of class (b) above may be any of those generally employed for such purposes including paper, woven or non-woven fabrics, finely meshed screen and the like.
• the colored products formed at elevated temperatures concentrate along the edges of the perforated portion of the thermoplastic film of the stencil and also adhere to the porous support so that it becomes possible to visually estimate the suitability of the stencil sheet for use in printing.
• thermographically color-developable compositions of this invention are capable of developing highly colored images even when employed in small amounts. This is particularly important in connection with the production of stencils which otherwise would have poor resolving power.
• stabilizing agent which may be an acid or a salt of an acid.
• Suitable stabilizing agents include inorganic acids such as sulfuric, hydrochloric, nitric, or phosphoric; or organic acids such as lauric, myristic, palmitic, stearic, erucic, behenic, abietic, naphthenic, oxalic, malonic, succinic, malic, tartaric, citric, maleic, cyanoacetic, benzoyl acetic, or benzoic.
• Ammonium or metallic salts of these acids especially sodium, potassium, zinc, lead and cadmium salts are also effective.
• EXAMPLE 1 Synthesis of semicarbazide derivative.--A solution was first prepared by dissolving 190 g. of methyl isocyanate into 250 ml. of ethanol. Subsequently, another solution prepared by mixing 230 g. of hydrazine hydrate of purity in 250 ml. of ethanol was slowly dropped into the former solution with continuous stirring and cooling whereby there were obtained white crystals of 4-methyl semicarbazide (having a melting point in the range of 1l61 17 C.). The crystals were then recrystallized from ethanol and dried. 108 g. of thus obtained 4-methyl semicarbazide was mixed with 167 g. of formic acid and 111 ml. of normal propanol, refluxed and cooled. The resultant white precipitate was recrystallized from ethanol, and there was obtained 1-formyl-4-methyl semicarbazide having a melting point in the range of 236238 C.
• Preparation of heat-sensitive copying material 20 g. of the powder obtained through the foregoing method was mixed in ml. of a 5%-toluene solution of a silicon resin and subjected to dispersion by means of a ball-mill for 5 hours, to form a suspension.
• Another suspension was prepared by mixing 30 g. of a ferrous salt of lauric acid and 100 ml. of 5% toluene solution of silicon resin for 8 hours on a ball mill. The two suspensions were mixed and the resultant mixture was coated onto a tracing paper to the extent of about 5,41. in thickness and dried in a cold air current to prepare a heat-sensitive copying material.
• thermographically copying machine manufactured by Minnesota Mining & Manufacturing Company
• This copying material when utilized for copying by employing a thermographically copying machine (Thermofax manufactured by Minnesota Mining & Manufacturing Company), produced a clear-cut image formed in brown color on a snow-White ground.
• the poststorage stability of the copy thus produced proved to be exceptionally good.
• Example 2 Synthesis of semicarbazide derivative-Utilizing phenyl isocyanate in lieu of methyl isocyanate used in case of Example 1 and employing a similar process, l-formyl-4- phenyl semicarbazide (having a melting point in the range of l72173 C.) was produced.
• Preparation of heat-sensitive stencil sheet By employing a mixture prepared by mixing 5 g. of the powder obtained through the foregoing method, 5 g. of a ferric salt of stearic acid (having a melting point in the range of 103 106 C.) and 1 g. of stearic acid as a stabilizer in 1300 ml. of 6%-methanol solution of polyvinyl acetate, and effecting thorough dispersion by means of a ball-mill for 24 hours, a bonding agent containing the thermographically color-developable composition was prepared.
• An original carrying the desired image printed thereon was superposed onto the film-side of thus obtained stencil sheet, and infrared rays were applied by way of the thin-paper side by employing the same thermographic copying machine employed in Example 1, to eifect perforation of the film.
• the extent of exposure was varied. A number of stencils were prepared. Those having a blue colored image on the perforated area well contrasted with the White background were used to produce prints of exceptional quality.
• Example 3 50 g. of cellulose-acetate-butyrate (namely, Half Second Butyrate manufactured by Eastman Chemical Co.) was dissolved in 500 ml. of acetone, and a solution thus obtained was mixed with 100 g. of hydrogenated abietic acid ester (a manufacture of Hercules Powder Co., USA, with the brand name Hercolin D) and 50 g. of a mineral oil having the aniline point of 97 C. The mixture thus obtained is hereinafter referred to as Solution A.
• a blended solution was prepared by mixing the foregoing Solutions A, B and C and it was coated and impregnated on and in a porous thin paper weighing about 10 g./m. so that the post-drying weight of the substance thus adhered to the thin paper be about g./m.
• the heat-sensitive stencil sheet thus prepared was subjected to processing utilizing the Thermofax machine, the stencil obtained by proper exposure was provided with an image having a green color well contrasted with the white background and formed only on the perforated area thereof.
• Example 4 Acetyl semicarbazide was prepared according to the procedure of Beilstein Organische Chemie, 1929, vol. III/IV p. 56, and 5 g. of the compound was taken up in 100 ml. of methanol. A mixture thus obtained is here inafter referred to as the Component A.
• Example 5 125 g. of benzazide and 100 g. of acetone-acetyl hydrazone were dissolved in anhydrous pure acetone and refluxed for 10 hours. The acetone was evaporated and lacetyl-4-phenyl semicarbazide was deposited from the boiled water (see Beilstein, 1910, vol. 7, p. 383).
• the thus obtained compound (20 g.) was dissolved in 100 ml. of l0%-methanol solution of ethyl cellulose. This solution is hereinafter referred to as the Component A.
• a coating liquid for use 1n conventional art-paper processing (viz. a solution prepared by dispersing clay in an aqueous solution of polyvinyl alcohol) on a smooth paper weighing g./m. and drying thereafter, a supporting sheet was prepared.
• equivalent amounts of the aforesaid Components A and B were thoroughly mixed with each other and applied on the coating layer of the supporting sheet, and dried by employing a warm air current having a temperature not exceeding 50 C.
• the dry weight of thus coated heat-sensitive layer was 5 g./m.
• Example 6 After fusing semicarbazide and anhydrous benzoic acid, and recrystallizing from water there was obtained 1- benzoyl-semicarbazide (see Beilstein, 1910, vol. 9, p. 327).
• Example 7 130 g. of hydrogen sulfate and 136 g. of crystalline sodium acetate were dissolved in 1300 ml. of water, and the solution was cooled and mixed with potassium cyanate. Thus treated solution was maintained weakly acidic with acetic acid and, 2 hours later, it was additionally mixed with 25 to 30 g. of potassium cyanate and left standing overnight to produce hydrodicarbonamide (see Beilstein, 192l,vol. 3,p. 116).
• Component A g. of this compound and 1 g. of sodium behenate were mixed in one liter of methanol. This solution is hereinafter referred to as Component A.
• Component B g. of ferric behenate, 6 g. of behenic acid, and 10 g. of talc were added to 500 ml. of a 3% solution of methyl cellulose and dispersed therein by mixing in a ball-mill for 10 hours. This dispersion is hereinafter referred to as Component B.
• Components A and B were thoroughly blended and applied to the extent of 15 g./m. dry weight on an art-paper weighing 100 g./m.
• the coating was dried by employing a warm air current having a temperature not exceeding 50 C.
• the heat sensitive sheet was utilized as in Example 5. There was obtained a black-colored copied image which was clear against the light brown texture.
• thermographicaly color-developable composition comprising an inert carrier containing (a) at least one iron salt which is a ferrous or ferric salt of a higher aliphatic carboxylic acid having at least 10 carbon atoms; and
• A is hydrogen, an alkyl or aryl radical which together with the 0:0 group to which it is attached forms an acyl or aroyl radical containing from about 1 to 20 carbon atoms, anilino or amino.
• composition as in claim 1 wherein the ratio of iron salt to semicarbazide derivative is about 1:0.1-2.0.
• a composition as in claim 1 stabilized by the addition of an effective amount of an acid, an ammonium salt of an acid or a metal salt of an acid.
• a composition of claim 1 wherein the semicarbazide derivative is 1-formyl-4-methyl semicarbazide and the iron salt is ferrous laurate.
• composition as in claim 1 wherein the semi-carbazide deriative is 1-formyl-4-phenyl semicarbazide and the iron salt is ferric stearate.
• composition as in claim 1 wherein the semi-carbazide derivative is hydrazine dicarbonanilide and the iron salt is ferrous palmitate.
• composition as in claim 1 wherein the semi-carbazide derivative is acetyl semicarbazide and the iron salt is ferric caprylate.
• composition as in claim 1 wherein the semicarbazide derivative is l-acetyl-4-phenyl semic'arbazide and the iron salt is ferric stearate.

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• 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)
• Printing Methods (AREA)
• Color Printing (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=11539347

Family Applications (1)

Country Status (6)

Cited By (8)

Families Citing this family (3)

• 1970
  • 1970-01-09 JP JP45002797A patent/JPS4913031B1/ja active Pending
  • 1970-04-30 DE DE19702021432 patent/DE2021432B2/de not_active Withdrawn
  • 1970-05-26 FR FR7019206A patent/FR2048845A5/fr not_active Expired
  • 1970-05-27 GB GB2550570A patent/GB1319073A/en not_active Expired
  • 1970-08-20 DK DK427670AA patent/DK126978B/da unknown
  • 1970-10-20 US US82518A patent/US3689302A/en not_active Expired - Lifetime

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