Classifications

• • 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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31551—Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
  • Y10T428/31645—Next to addition polymer from unsaturated monomers

Definitions

• a thin porous support having a thermoplastic resin film bonded to one surface thereof with an adhesive containing a heat-sensitive component which undergoes a visible color change at a temperature of from about 80 C. to 180 C. together with at least one heat-fusible compound which is a metallic salt of a fatty acid containing from about 10 to 22 carbon atoms and forms a transparent melt at a temperature of from about 50 C. to
• a thin porous support having a thermoplastic film bonded to one surface thereof with an adhesive, said film being coated with a mixture containing a heat-sensitive component which undergoes a visible color change at a temperature of from about 80 C. to 180 C. together with at least one heat-fusible compound which is a metallic salt of a fatty acid containing from about 10 to 22 carbon atoms and forms a transparent melt at a temperature of from about 50 C. to 150 C.
• This invention relates to heat-sensitive stencil sheets prepared by affixing a film comprising a thermoplastic resin to the surface ⁇ of a porous thin support, usually paper. More particularly, it relates to a heat-sensitive stencil sheet for use in mimeographic printing which may be converted to stencils with readily visible colored images on their top surface.
• Heat-sensitive stencil sheets are normally prepared to contain a thermoplastic resin film adhesively bound to a porous supporting sheet.
• Typical thermoplastic resins which may be employed include polystyrene, polyethylene, polypropylene, polyethylene and vinylidene chloridevinyl chloride copolymers. Copolymers of vinylidene chloride-vinyl chloride are especially favored.
• the thickness of the resin film is normally from about 5-10 microns.
• the weight of the porous supporting sheet is usually from about 8-18 g./m.
• It may be prepared, for example, from natural fibers obtained from mitsumata, paper mulberry, Manila hemp, and the like, or synthetic fibers such as rayon, polyvinyl alcohol synthetic fiber, polyethylene terephthalate synthetic fiber, acrylic resin, polyamide, or the like.
• synthetic fibers such as rayon, polyvinyl alcohol synthetic fiber, polyethylene terephthalate synthetic fiber, acrylic resin, polyamide, or the like.
• Other thermoplastic resins may be used in the film and other materials may be used to form the porous support sheet.
• the stencil sheets are used to prepare stencils and these in turn are utilized in the preparation of copies of an original.
• the original having the desired image is superposed upon the thermoplastic film surface of the stencil sheet and the original is exposed to electromagnetic waves, including infrared rays, usually from the porous support side of the stencil sheet.
• the infrared rays are absorbed by the image and converted to heat energy.
• the heat produced effects perforations of the film in areas congruent to the image areas of the original. Because the support is porous the resulting 3,715,263 Patented Feb. 6, 1973 stencil may be used to transfer ink to a copy sheet to reproduce the original thereon.
• the intensity of the electromagnetic waves i.e. the amount of exposure of the stencil sheet to such waves, will, of course, influence the clarity of the perforated image on the stencil. If the exposure is insuflicient the perforated image will be defective and there will result an indistinct image when the stencil is used for printing. If the exposure is excessive a similar result will be observed. Since the thermoplastic resin film on the porous support of the stencil sheet is extremely thin it is difiicult to judge by observation with the naked eye whether the perforated image on the stencil is one which will be capable of producing clear printed images. In the past it has been necessary to make such a determination by a trial and error method in which a number of stencil sheets are prepared and actually utilized in printing. The prints obtained are then compared to determine which of the several stencils is most suitable for the production of new copies. This procedure is expensive and time-consuming.
• the stencil sheets of this invention comprise a thin porous support having a thermoplastic resin film bonded to one surface thereof with an adhesive containing a heat-sensitive component which undergoes a visible color change at a temperature of from about C. to 180 C. together with at least one heatfusible compound which is a metallic salt of a fatty acid containing from about 10 to 22 carbon atoms and forms a transparent melt at a temperature of from about 50 C. to 150 C.
• the heat-sensitive component and the heat-fusible compound may be contained in a coating on the top surface of the thermoplastic resin film.
• Adhesives which may be employed for the preparation of the heat-sensitive stencil sheets of this invention may be any of those adhesives which are conventionally used in the preparation of ordinary stencil sheets.
• Vinyl adhesives particularly those prepared from polyvinyl acetate, vinyl acetate-ethylene copolymers, vinyl acetatemaleic acid copolymers, vinyl acetate-methylacrylate copolymers, vinyl acetate-acrylic acid copolymers, vinyl acetate-butyl methacrylic copolymers, and vinyl acetate crotonic acid copolymers are useful.
• Acrylic adhesives, particularly polyacrylic or polymethacrylic acid adhesives or their corresponding esters as well as acrylonitrile-methacrylic acid copolymers are especially favored.
• the adhesive will be utilized in alcoholic solution and the heat-sensitive component together with the heat-fusible compound can be similarly dissolved or susended in the alcoholic solution. It is, of course, possible that the adhesive may be a suspension of fine particles in a liquid medium. In any event, the adhesive composition containing the heat-sensitive component and the heatfusible compound is coated onto the thin porous substrate and the liquid evaporated.
• the heat-sensitive component and the heat-fusible compound will be selected so as to change color and fuse
• thermoplastic film becomes perforated. This may be in the temperature range from about 80 C. to 180 C. but with most films will be from about 120 C. to 170 C.
• the component may be a single compound or complex which changes color when exposed to heat or it may be a mixture of reactants which react together under the influence of heat to produce a new compound and to thereby effect a concurrent color change.
• a transparent or opaque colored visible image reproducing the image of the original is formed upon irradiation of the stencil sheet with infrared rays and resulting per foration of the thermoplastic film.
• the amount of heat-fusible compound in the adhesive for the preparation of the stencil sheets of this invention is desirably in the range of from about 0.1 to 1.0 part by weight for each part by weight of adhesive.
• the amount of visibly reactive heat-sensitive component is similarly from about 0.1 to 1.0 part by weight per part by weight of adhesive. In each instance the preferred range from the point of view of economy and ease of operation is from about 0.2 to 0.5 part by weight per each part of adhesive.
• the weight of the adhesive layer including the heatsensitive component and the heat-fusible compound is typically in the range of from about 0.5 to 5.0 g./m.
• heat-sensitive stencil sheets from which one can easily determine the appropriate amount of exposure to infrared radiation for the purpose of producing stencils suitable for use in mimeographic, rotary press printing, and the like, which will accurately reproduce the original image, can be prepared. While appreciable variations from this range are possible there is a general tendency towards lack of clarity in the perforated image as more or less of the adhesive, heat-sensitive component or heat-fusible compound is employed. If a quantity of adhesive which is much less than 0.5 g./m. is employed the thermoplastic film may not be adequately bound to the porous substrate and if the amount of adhesive greatly exceeds 5 g./m. the perforation efficiency of the stencil sheet may be adversely affected.
• the stencil sheet is prepared to have a coating containing the heat sensitive component and heat fusible compound
• a solution or dispersion of these ingredients in an appropriate solvent such as alcohol alone, a mixed solution of alcohol and ether or a mixed solution of alcohol and keto alcohol is coated on the top surface of the thermoplastic film of a stencil sheet prepared in advance by afiixing the film to a porous thin supporting sheet with an adhesive, thereby forming a coating of a heat sensitive visibly reactive component and a heat fusible compound.
• the film may be initially coated with the active ingredients and the coated film subsequently bonded to a porous thin substrate with an adhesive.
• Suitable solvents for use in coating the visibly reactive heat-sensitive component and heat fusible compound include alcohols such as ethanol, n-propanol, n-butanol and 2-ethyl butanol, ethers such as ethylene glycol-monomethyl ether, ethyleneglycol-monobutyl ether and diethyleneglycol-monoethyl ether, and keto alcohols such as diacetone alcohol.
• the visibly reactive heat-sensitive component and the heat fusible compound may be applied to the top surface of the film as a solution or a dispersion which may contain a small amount of the same adhesive which is used to bond the porous thin supporting sheet to the film.
• composition of a coating of this invention which contains a heat fusible compound and the visibly reactive heat-sensitive component is desirably mixed with the compound ranging from about 0.1 to 1 part by weight per one part by weight of said component.
• the weight of heat-sensitive component and heat fusible compound coated on the surface of the film will be from about 0.1 gr./m. to 3.0 gr./rn. If the weight deviated appreciably from this range it becomes difficult to judge the proper amount of exposure and there is interference with the perforation effciency. For example if the weight is as high at 6.0 g./m. it is extremely difficult to form a satisfactory image.
• heat-sensitive components Any of a wide variety of heat-sensitive components may be used in this invention including those already known for the production of heat-sensitive copy sheets. Typical examples of known components include those listed below.
• hexamethylenetetramine-cobalt chloride (COC12'2C5H12N4'10H20) (yellow-red) hexamethylenetetrarnine-cobalt iodide (light yellow-red), hexamethylenetetramine-cobalt bromide (light yellowred), hexamethylenetetramine-nickel chloride (light green), hexamethylenetetramine-nickel bromide (light green), hexamethylenetetraminc-cobalt nitrate or coblat surfate and hexamethylenetetramine-nickel nitrate or nickel sulfate.
• Typical examples of compounds having a secondary alcoholic hydroxyl radical include benzoin and its derivatives such as Z-methoxybenzoin, 4-chlorobenzoin, 4-dimethylaminobenzoin and Z-chloro 4 dimethylaminobenzoin; carbinols such as diphenylcarbinol, phenolic compounds such as resorcinol, pyrogallol, 3 hydroxytoluene 4 sulphonic acid, 4-nitroresorcinol and 4,6-dibromoresorcinol; aliphatic polyhydric alcohols such as erythritol, sorbitol, galactose, maltose, mannitol and saccharose.
• benzoin and its derivatives such as Z-methoxybenzoin, 4-chlorobenzoin, 4-dimethylaminobenzoin and Z-chloro 4 dimethylaminobenzoin
• carbinols such as diphenylcarbino
• Typical metallic salts include those which produce colored-sulfide compounds by reaction with sulfur such as sulfates, nitrates, carbonates and acetates of copper, lead, tin, molybdenum, cobalt, chromium, nickel, manganese, titanium, antimony, rhodium, mercury, iron, barium, bismuth, arsenic, magnesium, indium and iridium.
• Typical mixtures described in this publication include, for example, saccharose, fructose, galactose and starch as the carbohydrate, and sulfuric acid, acetic anhydride, zinc chloride anhydride and 'P-toluenesulfonic acid as the dehydrating agent.
• Heat-fusible compounds useful in this invention include metallic salts of saturated or unsaturated higher fatty acids having from about to 22 carbon atoms such as stearic acid, palmitic acid, lauric acid, myristic acid, oleic acid, erucic acid, behenic acid, etc., and at least one of these metallc salts is employed for mixing in the resinous solution for forming said ink-impermeable film.
• metallic salts of saturated or unsaturated higher fatty acids having from about to 22 carbon atoms such as stearic acid, palmitic acid, lauric acid, myristic acid, oleic acid, erucic acid, behenic acid, etc.
• metallc salts is employed for mixing in the resinous solution for forming said ink-impermeable film.
• a wide variety of metals are applicable including metals belonging to Group II of the Periodic Table such as calcium, zinc, cadmium, magnesium, etc.; lead belonging to Group IV; manganese belonging to Group
• fatty acids having less than 10 or more than 22 carbon atoms may be employed they are generally not practical. Those acids on the lower end of the range have offensive odors, and those on the higher end are difficult to obtain and are expensive.
• These heat-fusible compounds have the melting points from about 70 C. to 150 C. They should, of course, be reaction inert with respect to the heat-sensitive component.
• a particular advantage of this invention is that visibly reactive heat sensitive components which develop such a low density image that they are not useful in the preparation of heat sensitive copy sheets may be employed to produce stencil sheets.
• a copy sheet is a sheet which upon exposure to heat generated by absorption of infrared rays on an image to be copied will reproduce the image by the reaction of heat sensitive components contained therein.
• the adhesive Whether or not it contains the active ingredients may be coated onto the thin porous substrate or onto the film in any convenient manner, for example by roller coating, spraying or the like.
• a coating on the thermoplastic film may be similarly laid down.
• Stencils are prepared from the stencil sheets of this invention in the usual manner and, as expected, perforation takes place in the area of the ink-impermeable film congruent with the image area of the original.
• perforation takes place in the area of the ink-impermeable film congruent with the image area of the original.
• visibly reactive heat-sensitive component develops colors in the perforated areas and the melt concentrates at the edge of the perforated area to present a sharply outlined colored image.
• the presence of the heat-fusible compound causes the perforated image to be even more sharply outlined with improved clarity of color.
• the perforated area can be readily observed by the naked eye.
• the perforated area constitutes no obstacle to the permeability of the printing ink. It is readily possible to determine the optimum amount of infrared radiation and to foresee, from the clarity of the visible image on the stencil, the quality of the prints which can be produced.
• Example 1 To 1500 ml. of a 4.5%-methanol solution of vinyl acetate homopolymer were added 10 gr. of zinc stearate and 10 gr. of calcium stearate. The resultant mixture was mixed well for 3 hours in a. ball mil, and 2.0 gr. of diphenylcarbazone were added to prepare an adhesive solution containing the heat fusible compound and the visibly reactive heat-sensitive component.
• a 7,:r-thick transparent film comprising vinylidene chloride-vinylchloride copolymer as its principal component and a 30/L-thl0k porous thin supporting paper comprising manila hemp fibers as its principal component and weighing 9 gr. per square meter were affixed together by employing the foregoing adhesive solution.
• the application of the adhesive was effected by roll coating, and the amount of adhesive on the porous thin supporting paper was about 2.2 g./rn.
• a newspaper was superposed on the surface of the film of thus prepared stencil sheet, and the infrared-ray irradiation was applied (by employing Thermofax manufactured by 3-M Co., Ltd.) from the paper side of the stencil sheet to effect perforation.
• the image formed was a clearly visible red against a pink background.
• the stencil was employed for printing with a commercial mimeograph machine, and proved capable of producing a multiplicity of clear-cut prints which faithfully reproduced the original image.
• Example 2 sequently, by applying the thus prepared adhesive solution to a film and a porous thin supporting paper, the same as that employed in Example 1, a stencil sheet comprising the supporting paper and with the film bonded onto one surface with the adhesive was obtained.
• the optimum amount of exposure was 180 C. readily defefmined y Visual 0b$ ?rV at1011 aS in P 3.
• a stencil sheet as in claim 1 wherein the heat-sensil Stencll f pl y for Prlntlng Wlth a commefclal 10 tive component is a mixture of at least two reactants P It 1 to Capabla 9 P which react at a temperature of from about 80 C. to f f a 11111101111010 0f Pfmts faithfully P QduClng the 180 C. to form a new compound and effect a concurrent original. color change.
• Example 3 4.
• a heat-sensitive stencil sheet comprising a thin of the stencil sheets thus obtained, when subjected to 20 porous support having a thermoplastic film perforable infrared-ray exposure in accordance with the procedure of by heat at a temperature from about 80 C. to 180 C.
• Example 1 was equal to that observed with the stencil bonded to one surface thereof with an adhesive, said sheets of Examples land 2. film being coated with from about 0.1 g./m. to 3.0
• the following table shows some of the combinations g./m. of a mixture containing, for each part by weight employed: of coating, from about 0.1 to 1.0 parts by weight of a Mixing ratio: (Q/( Stencil (a) Vls1bly reactive (b) Heat fusible (part by sheet No. heat'sensitive component compound weight) Color 1 Hexamethylene tetrarnine'cobalt chloride Lead palmitate 3/1 Blue. 2 Fern'c steratate and gallic acid (3:1) Manganese stearate. 2/1 Blackish brown. 3 Lead oxalate and thiourea (1:1) Potassium palmitate 3/1 Do. 4 Silver behenate and protocatechuic a (6:1). Zine stearate 2. 3/1 Do. 5- Ferric laurate and thiosemicarbazide Magnesium myristate 2. 8/1 Do. 6 Cupic stearate and zinc dialkyldithiocarbamate Cobalt myn'state 2. 5/1 Do.
• Example 4 heat sensitive component which undergoes a visible color To 800 ml. of 4.5 %-methanol solution of polyvinyl ace- 40 change to form a colored lmage g the porolls support at a temperature of from about 80 C. to 180 C. together tate there was added 10 gr. of nickel laurate as a heat with for each art b Wei ht of coafn from b t 01 fusible compound and a visible reactive heat-sensitive to art b g of i least i f 3 2 component consisting of 20 gr. of diphenyl nitrosamine p g u pound WhlCh 1s a metallic salt of a fatty acid contaimng and 5 gr. of protocatechuic acid.
• the sol1d was dispersed f b t 10 22 b d f in the S 01 mi on. rom a 0111 to car on atirm an borms a trans-
• the resultant dispersion was applied onto a 7 -thick, iggi at a temperature 0 mm out to transParent film contqmmg. vinyhdene chlonde'vmyl' 7.
• a heat-sensitive stencil sheet comprising a thin UNITED STATES PATENTS porous support having a thermoplastic resin film pcr- 1,753,204 4/1930 Horii .117 35,5 forable by heat at a temperature of from about 80 C. 2,354,855 8/ 1944 Emanuel 215 40 to 180 C. bonded to one surface thereof with from 2,663,654 12/ 1953 Miller et al 11736.8 about 0.5 to 5 g./m.

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• Printing Plates And Materials Therefor (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=14021704

Family Applications (1)

Country Status (3)

Cited By (1)

• 1970
  • 1970-09-29 DK DK496570AA patent/DK126910B/da unknown
  • 1970-11-06 GB GB5293770A patent/GB1312270A/en not_active Expired
  • 1970-11-13 US US00089453A patent/US3715263A/en not_active Expired - Lifetime
• 1972
  • 1972-04-07 DK DK169572AA patent/DK127463B/da unknown

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