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
  • B41M5/124—Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components
  • B41M5/132—Chemical colour-forming components; Additives or binders therefor
  • B41M5/155—Colour-developing components, e.g. acidic compounds; Additives or binders therefor; Layers containing such colour-developing components, additives or binders

Definitions

• a sensitized sheet for a pressure sensitive copy system is obtained by coating the surface of a support with an acceptor composition comprising a particulate mixl30l Foreign Application Priority Data ture comprising an organic acid substance selected Sept. 17. 1972 Japan 47-97430 from the group consisting of aromatic carboxylic acids and polyvalent metal salts thereof, and an organic high [52] U.S. Cl. 427/147; 427/146; 427/150 molecular compound.
• the above coating composition [51 Int. Cl. 841M 5/00 may further contain an inorganic solid particle such as [58] Field of Search 1 17/368, 36.2. 36.7; oxides, hydroxides and carbonates of a polyvalent 427/147, 150, 146 metal, and other mineral pigments.
• the coating procedure may be carried out with use of coating means [56] References Cited mounted on the conventional paper machines.
• the present invention relates'to a sensitized sheet for use in a pressure sensitive copy system and particularly relates to the sensitized sheet having a coating comprising an acceptor which is capable of color forming when coming into contact with a colorless chromogenic compound.
• the pressure sensitive copy system of the invention utilizes a color forming reaction between an electron donating colorless compound and an electron accepting solid acid.
• US. Pat. No. 2,730,456 discloses a transfer type of the pressure sensitive recording sheets wherein an upper sheet or overlying sheet is coated with a layer containing micro-capsules in which an electron donating colorless compound (hereinafter referred to as color former) dissolved in an oily solvent is enveloped, and an underlying sheet is sensitized with a coating layer containing an electron accepting solid acid (hereinafter referred to as acceptor).
• color former an electron donating colorless compound
• acceptor an electron accepting solid acid
• U.S. Pat. No. 2,730,457 discloses a recording sheet wherein both of the fine capsules and acceptor are coated on the same side, so called self contained copying sheet".
• German Pat. No. 1,275,550 discloses a pressure sensitive recording sheet wherein a record forming components soluble in a liquid solvent is carried on the surface and/or inside of a support and said solvent is present isolated from at least one of said record forming components by pressure-rupturable capsules.
• color former examples include Leuco type of chromogenic compounds such as Crystal Violet Lactone, Benzoyl Leucomethylene Blue, Malachite Green Lactone, Rhodamine B Lactone, fluoran derivatives and spiropyranes.
• acceptors include acid clay, activated clay, attapulgite, kaolin and other inorganic solid acids, but there are disadvantages that a developed color image is faded by the action of moisture and sunlight.
• a sensitive sheet coated with organic solid acid such as phenolic resins is also used. However, such a sheet is apt to yellow by the sunlight and the developed color image is decreased in density or allowed to disappear for a little while by heat or moisture.
• aromatic carboxylic acids U.S. Pat. Nos. 3,322,557 and 3,488,207
• polyvalent metal salts of aromatic carboxylic acid DT-OS 2,152,765
• benzoic acid omitrobenzoic acid
• o-chlorobenzoic acid 4-methyl-3-nitroben-.
• zoic acid p-isopropylbenzoic acid, p-terL-butylbenzoic acid, salicylicacid, 5-tert.-butylsalicylic acid, 3- cyclohexylsalicylic acid, 3-methyl-5-isoamylsalicylic acid, 3,5-dinitrosalicylic acid, l-naphthoic acid, 1- hydroxy-Z-naphthoic acid, 5,5-methylen-disalicylic acid and the other similar aromatic carboxylic acids, and salts of metals such as magnesium, calcium, zinc, cadmium, aluminum, gallium, tin, lead, chromium, molybdenum, manganese, cobalt and nickel with the above carboxylic acids.
• metals such as magnesium, calcium, zinc, cadmium, aluminum, gallium, tin, lead, chromium, molybdenum, manganese, cobalt and nickel with the above carboxylic acids.
• aromatic carboxylic acids and polyvalent metal salts thereof are superior in stability toward the sunlight to the phenolic resins.
• Some of the aromatic carboxylic acids and polyvalent metal salts thereof have a sublimating property, and therefore a sheet sensitized by a coating containing such acceptors loses a color-formin g ability with the lapse of time. Since the said acceptors are relatively soluble in water and thus diffuse within the sheet by the action of high moisture or water, the color-forming ability is lost on the surface of the sheet.
• Such disadvantages show an increasing tendency as the molecular weight of aromatic carboxylic acid is lowered. The reason why saliv thereof show improved resistance toward heat and moisture as the molecular weight increases and can maintain relatively stable color-forming properties at normal temperature and humidity.
• the pressure sensitive recording papers leave room for further improvements of the properties to be required in practice. It is unavoidable that the recording papers are stored and handled under the condition of high humidity or water attaches directly to the sheet. For example, it often occurs that rainwater or water spilt from a glass attaches to the sheet. In some cases, when a letter or figure is printed by offset printing on the upper or underlying sheet of pressure sensitive recording papers, fountain solution on the blanket transfers onto an acceptor coated surface of the sheet.
• a coating layer containing the acceptor must have a high humidity or water resistance sufficient to maintain stabilities of the color-forming ability and developed color image and to inhibit the smudge.
• a coating composition containing aromatic carboxylic acids and polyvalent metal salts thereof because of being unstable toward heat in general, needs a careful watch and handling during storage or coating procedure.
• the coating composition is subject to mechanical shear and accompanied by a rising temperature. Therefore, when a mechanical and thermal stability is insufficient, the coating composition cannot form a uniform layer on the surface of a base sheet and in the worst case it is unavoidable to discontinue the coating procedure. If the coating procedure is efi'ected by a coating apparatus mounted on a paper machine, it is the most simplified process and therefore advantageous economically. ln this case since the coating composition is coated on the base sheet preheated by a dryer, the mechanical and thermal stability requirements become more severe.
• a sensitized sheet for use in a pressure sensitive copy system, having a coating comprising an acceptor, the acceptor being a particulate mixture of (a) an organic acid substance selected from the group consisting of aromatic carboxylic acids and polyvalent metal salts thereof, and (b) an organic high molecular compound.
• the mixture of the organic acid substance and organic high molecular compound can be pulverized to uniform fine powders of several microns in particle size by mechanical means, for example ball-milling.
• a coating layer having the fine powders homogeneously dispersed therein is obtained and therefore the distinct images are obtained.
• the organic acid substance to be used in the invention is selected from the group consisting of aromatic carboxylic acids and polyvalent metal salts thereof.
• aromatic carboxylic acids and polyvalent metal salts thereof useful for the acceptor are in detail explained in US. Pat. application Ser. No. 265,484, filed June 23, 1972, now abandoned, which discloses the pressure sensitive record system. These compounds are illustrated by non-limitative examples as given hereunder, but it should of course be understood that other aromatic carboxylic acids and polyvalent metal salts thereof, capable of color forming when brought into contact with a color former may be also used.
• An aromatic carboxylic acid to be used is represented by the formula 1,
• R,, R R R and R each represents hydrogen, halogen or a hydroxyl, amino, carboxyl, carbamoyl, N-substituted carbamoyl, alkyl, cycloalkyl, alkoxyl, aryloxy, aralkyl or alkylaryl group, and any adjacent pair of R, to R, can, together with the carbon atoms to which they are attached, complete a ring.
• Compounds of formula I wherein R, or R is a hydroxyl group are especially important in embodiments of the invention as mentioned in detail hereinafter.
• aromatic carboxylic acids of formula I wherein R, and R are not a hydroxyl group include benzoic acid, o-toluic acid, m-toluic acid, p-toluic acid, p-tert.-butylbenzoic acid, o-chlorobenzoic acid, mchlorobenzoic acid, p-chlorobenzoic acid, dichlorobenzoic acid, trichlorobenzoic acid, tetrachlorobenzoic acid, phthalic acid, isophthalic acid, terephthalic acid, Z-carboxybiphenol, p-oxybenzoic acid, paramethoxybenzoic acid, p-butoxybenzoic acid, p-octoxybenzoic acid, gallic acid, anthranilic acid, phthalic acid monoamide, phthalic acid monoanilide, 3-tert.-butyl-4- hydroxybenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid
• Aromatic carboxylic acids of formula I wherein R, or R is a hydroxyl group are defined by formula II,
• carboxylic acids examples include salicylic acid, o-cresotinic acid, p-cresotinic acid, 3-ethylsalicylic acid, 4-ethylsalicylic acid, 3-isopropylsalicylic acid, 4-isopropylsalicylic acid, 5-isopropylsalicylic acid, 3- tert.-butylsalicylic acid, 5-tert.-butylsalicylic acid, 3- cyclohexylsalicylic acid, 5-cyclohexylsalicylic acid, 3- phenylsalicylic acid, S-phenylsalicylic acid, 3-benzylsalicylic acid, 5-tert.-octylsalicylic acid, 3-(a-methylbenzyl) salicylic acid, S-(a-methylbenzyl) salicylic acid, 5-nonyl salicylic acid, 5-(oz,a-dimethylbenzyl) salicylic acid,
• aromatic carboxylic acids examples include 3,5- dichlorosalicylic acid, 3-chloro-5-tert.-butylsalicylic acid, 3-chloro-5-tert.-amylsalicylic acid, 3-chloro-5- tert.-octylsalicyclic acid, 3-chloro-5-( a,a-dimethylbenzyl) salicylic acid, 3,5-dimethylsalicylic acid, 3-methyl- 5-tert.-butylsalicylic acid, 3-methyl-5-cyclohexylsalicylic acid, 3-methyl-5-tert.-octylsalicylic acid, 3-methyl- S-(a-methylbenzyl) salicylic acid, 3-methyl-5-nonylsalicylic acid, 3-methyl-5-(a,a-dimethylbenzyl salicylic acid, 3,5-diisopropylsalicylic acid, 3,5-di-sec.-butylsalicylic acid, 3-tert.
• Aromatic carboxylic acids of formula ll in which R or R is alkyl, cycloalkyl or phenyl can be derived from, for example, metracresol, metapropylphenol, metaphenylphenol, 2,3-xylenol, 2,5-xylen0l, 3,4-xylenol and 3,5-xylen0l.
• carboxylic acids examples include 3,4-dimethylsalicylic acid, 4,5-dimethylsalicylic acid, 4,6-dimethylsalicylic acid, 4-methyl-5-isopropylsalicylic acid, 4-methyl-5-sec.-butylsalicylic acid, 4-methyl- 5-tert.-butylsalicylic acid, 4-methyl-S-terL-amylsalicylic acid, 4-methyl-5-cycl0hexylsalicylic acid, 4-methyl- S-benzylsalicylic acid, 4-methyl-5-tert.-octylsalicylic acid, 4-methyl-5-(a-methylbenzyl) salicylic acid, 4- methyl-S -nonylsalicylic acid, 4-methyl-5-(a,a-dimethylbenzyl) salicylic acid, 3,6-dimethylsalicylic acid, 3- tert.-butyl-6-methylsalicylic acid, 3-tert.-amyl-6- methyl
• Aromatic carboxylic acids of formula II in which at least one of R to R is a hydroxyl group are presented by formula III,
• hydroxysalicylic acid 4-tert.-butyl-5-hydroxysalicylic acid, 4-tert.-amyl-5-hydroxysalicylic acid, 4-cyclohexyl-S-hydroxysalicylic acid, 4-(a-methylbenzyl)-5- hydroxysalicylic acid, 3,6-diisopropyl-S-hydroxysalicylic acid, 3,6-dicyclohexyl-S-hydroxysalicylic acid or 3,6-di( a-methylbenzyl)-5-hydroxy-salicylic acid.
• R, R' R;,, R',,, R' R' R and R each is hydrogen, halogen or a hydroxyl, alkyl cycloalkyl or aralkyl group.
• naphthalene derivatives there are indicated l-hydroxy-2-carboxynaphthalene, l-hydroxy-2-carboxy-4-isopropylnaphthalene, lhydroxy-Z-carboxy-4-cyclohexylnaphthalene, l-hydrogen-Z-carboxy-4-benzylnaphthalene, l-hydroxy-Z-carboxy-4-(a-methylbenzyl) naphthalene, l-hydroxy-2- carboxy-7-isopropylnaphthalene, l-hydroxy-Z-carboxy-7-tert.-butylnaphthalene, l-hydroxy-2-carboxy-7- tert.-amylnaphthalene, 1-hydroxy-2-carboxy-7- cyclohexylnaphthalene, 1-hydroxy-2-carboxy-7-tert.- octylnaphthalene, l-hydroxy-2- carboxy-7-(a)
• Aromatic carboxylic acids derived from, for example, bisphenol A, 4,4-dihydroxycyclohexylidenebiphenyl, 4,4'dihydroxymethylenebiphenyl and 2,2dihydroxydiphenyloxide are regarded as condensates of salicylic acid.
• carboxylic acids examples include 5-(4'-hydroxybenzyl) salicylic acid, 5-(3'-carboxy-4- hydroxybenzyl) salicylic acid (methylene-bis-salicylic acid), 3-tert.-butyl-5-(3,5-di-tert.-butyl-4-hydroxybenzyl) salicylic acid, 3-(a,a-dimethylbenzyl)-5- ⁇ 3,5'- di( 0:,oz-dimethylbenzyl -4 -hydroxybe nzyl ⁇ salicylic acid, 3-tert.- butyl-5-( a,a-dimethyl-3 ,5 '-di-tert.-butyl-4 -hydroxybenzyl) salicylic acid, 5-(a,a-dimethyl-3-carboxy-4'- hydroxybenzyl) salicylic acid, 5-(a,a-dimethyl-4- hydroxybenzyl) salicylic acid, 3-(2-hydroxyphenoxy) salicylic acid, 3-(
• aromatic carboxylic acids and polyvalent metal salts thereof used herein and in the claims include also the condensates and polymerizates as mentioned above and polyvalent metal salts thereof.
• Polyvalent metals which are concerned with the acceptors of the present invention represent all the saltforming metals other than lithium, sodium, potassium, rubidium, cesium and francium.
• the useful polyvalent metals include magnesium, aluminum, calcium, scandium, titanium, vanadium. chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, strontium, yttrium, zirconium, niobium, molybdenum, silver, cadmium, indium, tin, antimony, barium, tungsten, mercury, lead and bismuth.
• magnesium, aluminum, calcium, titanium, manganese, zinc and tin are magnesium, aluminum, calcium, titanium, manganese, zinc and tin.
• aromatic carboxylic acids and polyvalent metal salts thereof compounds having at least one hydroxyl group on the benzene ring. particularly a hydroxyl group at the ortho-position to the carboxyl group are preferred from the point of view of color-forming ability. From aspects of the heat and moisture resistances and the compatibility with an organic high molecular compound, an aromatic carboxylic acid and polyvalent metal salt thereof, having higher molecular weight are preferred, that is, ones having 10 or more, preferably 17 or more carbon atoms in total are recommended.
• Compounds of formulae II, III, IV, V and VI bearing at least one of S-membered and 6-membered carbon-rings as substituents and having 17 or more carbon atoms in total are most preferred.
• the polyvalent metal salts of aromatic carboxylic acid are obtained by reaction of aromatic carboxylic acids with oxides, hydroxides, carbonates and silicates of polyvalent metals, though they are conveniently obtained by a double decomposition of an alkali metal salt of aromatic carboxylic acid and a water soluble polyvalent metal salt.
• the aromatic carboxylic acid and water soluble polyvalent metal salt each may be used alone or in mixture of two or more.
• the polyva lent metal salts of aromatic carboxylic acid are usually obtained in form of crystalline powders, amorphous fine powders or viscous liquids.
• An organic high molecular compound used in the invention should show an easily non-fluidifying property at normal temperature and preferably is selected from ones having a molecular weight of about 400 or more.
• Styrene polymers styrene copolymers, a-methylstyrene polymers, a-methylstyrene copolymers and substituted phenolformaldehyde polymerization condensation products are preferred. These high molecular compounds have good compatibility with various types of the organic acid substance and therefore are easily pulverized to fine powders, and maintain a good color'forming property.
• organic high molecular compound prefferably selected from compounds having compatibility with the organic acid substance to be incorporated therein.
• compatibility means such property that two or more chemical substances dissolve with one another and also such property that the dissolution occurs only in the one because of the other being crystalline.
• the compatibility of a chemical substance may be explained in relation with polarity of the substance.
• a suitable combination of the organic acid substance and high molecular compound in the present invention will be determined taking this point of view into consideration.
• the polarity of chemical substance is qualitatively understood in the light of the balance between an inorganophile and an organophile.
• An aromatic carboxylic acid is usually increased in the organophile and lowered in the polarity as the number of carbon atoms becomes large.
• aromatic carboxylic acids having the same number of carbon atoms as polar radicals such as hydroxyl, carboxyl, nitro, cyano, and halogen are introduced into the molecule, the polarity becomes higher.
• the polarity may also vary depending upon the type of radicals and the position of radicals in the molecular.
• Types of polyvalent metals have influence on the compatibility which may be explained in relation with the polarity.
• many of polyvalent metals which tend to form polyvalent metal salts having a high inorganophile or high polarity are metals with a relatively small atomic weight such as magnesium, aluminum, calcium and titanium.
• zinc and tin tend to form polyvalent metal salts with low inorganophile or low polarity.
• a pulverized homogeneous mixture comprising an organic acid substance and organic high molecular compound is obtained by selecting the organic high molecular compound having the similar polarity to that of an aromatic carboxylic acid and polyvalent metal salt.
• An organic high molecular compound compatible with an organic acid substance of a relatively high polarity is selected from one with a high polarity which bears polar radicals in the molecule.
• Halogen and a phenyl radical show no obstacle to the color reaction.
• hydroxyl and carboxyl radicals have no obstacle to the color reaction and raise the polarity in the presence of a small number of radicals.
• an incorporation ratio of the organic high molecular compound to the organic acid substance is not particularly limited, when the amount of the former is too little. the desired resistance toward heat, light and particularly a high moisture or water cannot be attained. It is desirable to incorporate the organic high 1 1 molecular compound in the amount of 5 parts by dry weight or more, preferably from to 300 parts by weight based upon 100 parts by dry weight of the organic acid substance.
• the most simple and preferable method includes the steps of mixing and melting the organic high molecular compound and organic acid substance while heating, solidifying the resultant by cooling and then pulverizing it.
• Another method includes the steps of dissolving the organic acid substance and high molecular compound in an organic solvent therefor and mixing same, evaporating the resultant to dryness and then pulverizing it.
• the pulverizing may be effected in a dry system or in a wet system with a medium such as water. In this case surface active agents and fine powders with high hardness such as silicic anhydride and kaolin may be allowed to co-exist in order to raise pulverization efficiency.
• organic high molecular compound used in the above described methods one having a relatively high glass transition point (second order transition point) and a relatively low molecular weight, is preferred. It is, in general said that an organic high molecular compound having a large number of ring-structures in the molecule shows a high second order transition point.
• polystyrene styrenea-methylstyrene copolymers, a-methylstyrene polymers, cyclopentadiene copolymers, aliphatic unsaturated cyclic hydrocarbon polymers, benzylchloridediphenyl poly-condensation products, meta-xylene-formaldehyde poly-condensation product, meta-xylenediphenyl-formaldehyde copolycondensation products, meta-xylene-alkylphenol-formaldehyde copoly-condensation products, meta-xylene-diphenyl oxideformaldehyde copoly-condensation products, diphenyl-formaldehyde polycondensation products, diphenyl-alkylphenol copoly-condensation products, substituted phenol-formaldehyde poly-condensation products, substituted phenol-dipheny
• a particulate mixture in water dispersed form is obtained by liquidizing the organic acid substance and high molecular compound by heating or addition of an organic solvent, dispersing in water the resultant, and cooling same or if necessary, removing the organic solvent.
• Further alternative method includes the steps of mixing the organic acid substance and an initiator and regulator for polymerization with a vinyl monomer capable of dissolving the organic acid substance, such as styrene, oz-methylstyrene, ethylacrylate and methylmethacrylate, and effecting a suspension or emulsion polymerization in water thereby to obtain a particulate mixture consisting of the organic acid substance and organic high molecular compound.
• a vinyl monomer capable of dissolving the organic acid substance such as styrene, oz-methylstyrene, ethylacrylate and methylmethacrylate
• an alternative method for obtaining the particulate mixture includes the steps of adding an alkali metal or ammonium salt of aromatic carboxylic acids into an emulsion of organic high molecular compounds, for example polystyrene emulsion and styrenebutadiene copolymer emulsion, further adding an acid or an aqueous solution of polyvalent metal salts thereto and effecting an acid decomposition or double decom- 12 position.
• heating may be effected in order to promote the diffusion of the aromatic carboxylic acid or polyvalent metal salt thereof into the particles of the emulsified organic high molecular compound.
• a finely pulverized mixture is thus obtained in the form of an emulsion or dispersion in water.
• the organic acid substance and organic high molecular compound completely dissolve with each other and form a homogeneous phase, but even though non-dissolving portions are in part present in the homogeneous phase, it does not at all obstruct the objects of the invention.
• the fine powders obtained are controlled to a particle size of normally less than several microns, preferably about 0.5 ;1..
• the particulate mixture may be further incorporated with at least one of a water-insoluble inorganic material, in the form of particles, such as oxides, hydroxides and carbonates of a metal, and other mineral pigment, and an organic material in form of powder such as powdered starch, powdered celluloses and organic pigments.
• a water-insoluble inorganic material in form of particles such as clay, kaolin, activated clay, zinc oxide, calcium carbonate and aluminum hydroxide is further incorporated therewith, solidified by cooling and pulverized.
• a particulate substrate in which the mixture of the organic acid substance and organic high molecular compound is adsorbed around the inorganic powders is obtained.
• the additional incorporation of the inorganic powders brings about extending effect for the particulate substrate and improvement in fluidity of coating composition.
• the incorporation of the inorganic powders improves a color-forming property of the organic acid substance as well as resistance of a sensitized sheet toward the sun light.
• An incorporation amount of the inorganic or organic powders is not particularly limited so far as the nature of the organic acid substance does not recede. It is usually preferred to incorporate the inorganic and/or organic powders in an amount of less than 2000 parts by dry weight based on parts by dry weight of the organic acid substance.
• an aliphatic carboxylic acid and/or polyvalent metal salt thereof is preferred.
• aliphatic carboxylic acid examples include a saturated monocarboxylic acid represented by the formula, C I-I ,COOI-I wherein n is an integer, for example valeric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid or a petrochemically derived synthetic fatty acid, an unsaturated or cyclic mono-carboxylic acid represented by the formula, C,,I-I ,,,COOH wherein n is an integer and m is an integer of l, 3, 5, 7 or 9, for example, acrylic acid, crotonic acid, oleic acid, elaidic acid, erucic acid, linolic acid, linolenic acid, eleostearic acid, phenylacetic acid or naphthylacetic acid, a monooxyfatty acid such as lactic acid, ricinolic acid or oxystearic acid, a halogen
• a metal salt of the above aliphatic carboxylic acids may be also used for the same purpose as mentioned above. These compounds include salts of all the metals which can form the salts with the above fattyacids.
• the aliphatic carboxylic acids and metal salts thereof may be preferably used in an amount of less than about 100 parts by dry weight in respect of 100 parts by dry weight of the organic acid substance and organic high molecular compound in total.
• a coating composition according to the invention is obtained by dispersing the particulate mixture comprising the organic acid substance and organic high molecular compound, if necessary, with a suitable binder into water or a suitable organic solvent which does not easily dissolve the organic acid substance and high molecular compound.
• a suitable organic solvent is exemplified by methanol, ethanol, isopropanal, ethylene glycol and propylene glycol, and may be used in mixture with water.
• binder examples include starch, casein, gelatine, gum arabic, polyvinyl alcohol, polyacrylamide, acrylamidemethylol acrylamide copolymer, acrylamide-acrylonitrile copolymer, methylolacrylamideacrylic ester copolymer, acrylamide-acrylic ester copolymer, acrylic acid-acrylic ester copolymer, methyl cellulose, melamine resins, urea resins, sodium polyacrylate, carboxymethyl cellulose, car'boxyethyl cellulose, natural rubber, synthetic rubber, polyacrylic acid ester, polymethacrylic acid ester, polyvinyl acetate, vinyl acetate-ethylene copolymer, polypropylene, polystyrene, polyisobutylene, vinyl chloride-vinyl acetate copolymer, methyl cellulose, ethyl cellulose, nitrocellulose, cellulose acetate, phenol resins, butyral resins, petroleum resins and alkyd resins.
• the binders particularly water-soluble binders can be added with chemical linking agents for forming waterinsoluble binders by the reaction.
• a water insoluble binder is used in the condition of suspension or emulsion in water.
• a carboxyl-modified polymer emulsion is particularly preferred because it is quite stable in coatings and shows sufficient adhesive property in a small quantity.
• examples of such an emulsion are carboxylated styrene-butadiene copolymer emulsion, carboxylated methylmethacrylate-butadiene emulsion and vinyl acetate-crotonic acid copolymer emulsion.
• the binders are used in a mixture of two or more, and a suitable combination of water-soluble and waterinsoluble binders is usually used.
• the coating composition of the invention may contain water-insoluble oxides, hydroxide and carbonates of a metal and/or other mineral pigments.
• Particularly such metal compounds as oxides, hydroxides and carbonates of a polyvalent metal exhibit an excellent col or-forming property in co-existence with the aromatic carboxylic acids. Therefore, these metal compounds are quite effective to be used in combination with some of aromatic carboxylic acids which are considered as disadvantageous in practice because of an inactive 14 color reaction and low color density.
• Suitable inorganic metal compounds are oxides, hydroxides, and carbonates of such a metal as magnesium, calcium, barium, zinc, titanium, aluminum, nickel, cobalt, manganese, iron, tin, chromium, and palladium, and for example, magnesium oxide, calcium oxide, barium oxide, zinc oxide, aluminum oxide, tin oxide, magnesium hydroxide, calcium hydroxide, zinc hydroxide, aluminum hydroxide, tin hydroxide, magnesium carbonate, calcium carbonate and zinc carbonate are particularly preferred.
• the above inorganic metal compounds which generally belong to the class referred to as mineral pigments have little color-forming ability by themselves, but exhibit nevertheless the especial color-forming ability in combination with the aromatic carboxylic acids.
• the above specified metal compounds are, therefore, referred to especially as inorganic metal compounds herein and distinguished from the conventional mineral pigments.
• the mineral pigments other than the inorganic metal compounds to be used are exemplified by activated clay, acid clay, aluminum silicate, zinc silicate, tin silicate, a colloidal aluminum hydrosilicate zeolite, bentonite, kaolin and talc. They are referred to merely as mineral pigment in the invention.
• the coating composition may include the above defined inorganic metal compound and mineral pigment in an amount of l to 10,000, preferably 5 to 1,000 parts by dry weight in respect of parts by dry weight of the aromatic carboxylic acid and/or polyvalent metal salt thereof. It should be understood that the coating composition may contain all or a part of the inorganic metal compound and mineral pigment incorporated in the particulate substrate comprising the organic acid substance and organic high molecular compound as mentioned hereinbefore.
• the desired coating compositions for some types of self-contained copying papers contain further fine capsules enveloping the color former therein.
• the coating composition is applied on the surface of a support by the conventional coating means, for example an air knife, rolls, blades and a sizing press or said composition is printed on the support by the printing press, for example a letter press and flexographic method.
• the printing method is preferred and the coating composition may contain further a plasticizer such as tributyl phosphate, dibutyl phthalate, dioctyl phthalate, butyl adipate and castor oil.
• a paper of natural fibers, a paper of synthetic fibers and a film of synthetic polymers may be used as the support, though the paper of natural fibers is usually used.
• the support if necessary, may be one having a barrier-coat of a natural or synthetic high molecular substance.
• the sensitized sheet according to the invention has advantages as described hereunder.
• the organic acid substance because of being prevented from the actions of heat, light and particularly high moisture or water by the organic high molecular compound, can maintain a stable color-forming ability for a long time and completely prevent the smudge. Accordingly, an organic acid substance with a relatively low molecular weight such as salicylic acid or its polyvalent metal salt which was unsuitable for practical use can be now put to practical use.
• the coating composition because of being excellent in mechanical and thermal stability, can be preserved in a state of perfection and also the coating work can be easily effected. Further, it is possible to apply it on the support by a coating apparatus mounted on the paper machine so that the pressure sensitive recording sheets are obtained in extremely economical way.
• the particular mixture comprising the organic acid substance and organic high molecular compound can be pulverized to fine powders with an uniform particle size of several microns by the mechanical means, for example ball milling. It is, therefore, possible to form a coating layer in which the fine powders are homogeneously dispersed so that clear images free of bleeding are obtained.
• the coating composition is usually applied in an amount of more than about 2g/m and the upper limit is confined by a mere economical reason.
• EXAMPLE 1 100 parts of a thermoplastic modified xylene resin with a softening point of l C (solid as Nikanol S-l00 by Mitsubishi Gas Chemistry Co., Japan) were heated to 180C, added with 90 parts of zinc 3,5-di(a,adimethylbenzyl) salicylate while stirring, and dissolved. A mass was obtained by cooling and solidifying the mixture. The mass was coarsely crushed and then pulverized with 200 parts of kaolin and 30 parts of a powdered silicic anhydride (sold as Carplex No. 80 by Shionogi Pharmaceutical Co., Japan) in a ball mill for hours. A particulate mixture with an average particle size of about 3 ,u. were, thus, obtained.
• a thermoplastic modified xylene resin with a softening point of l C solid as Nikanol S-l00 by Mitsubishi Gas Chemistry Co., Japan
• a coating composition was, thus, obtained.
• a sensitized sheet was obtained by applying the coating composition on the surface of a continuously running paper web of SOg/m in an amount of IOg/m by dry weight, using a pilot paper machine (sold as RlSSAR PAPER MACHINE by Mitsubishi Kakoki Co. Japan) provided with the similar coater to a commercial coater in large scale.
• the coating composition was applied on the surface of a preheated paper web and recycled during the coating work. As the result the coating composition was subject to mechanical shearing and concurrently reached the temperature of 70C at the highest, but maintained a markedly stable fluidity without increase of viscosity.
• EXAMPLE 2-1 2-14 100 parts of oz-methylstyrene-styrene copolymer with a molecular weight of about 1500 obtained by polymerization of 60 wt.% of oe-methylstyrene and 40 wt.% of styrene in the presence of thioglycolic acid were incorporated into and melted with 200 parts of each of organic acid substances as given hereunder at temperatures of 150 to 190C to form a homogeneous liquid phase. An easily crushable mass was obtained by cooling the liquid phase.
• Zinc 3,5-dicyclohexyl salicylate 200 parts of each of the mass thus obtained were crushed to an average particle size of about 200 u, incorporated with one part of a formaldehyde-sodium naphthalenesulfonate condensate (sold as Demol-N by Kao Atlas Co.
• Sensitized sheets were obtained by applying each of the coating compositions on a support in an amount of 7g/m by dry weight in the same manner as in Example 1. All of the coating compositions exhibited an excellent mechanical and thermal stability during the coating work.
• EXAMPLE 3-1 3-14 200 parts of each of the mass obtained in Example 2 were crushed to an average particle size of about 200 u, incorporated with 200 parts of kaolin, 50 parts of zinc oxide, 600 parts of water, 40 parts of a soluble starch and one part of Demol-N (see Example 2), and then pulverized in a sand grind mill. Finally, 100 parts of a carboxylated styrene-butadiene copolymerization latex (solids, 50%) were added thereto the obtained various coating compositions.
• a carboxylated styrene-butadiene copolymerization latex solids, 50%
• Sensitized sheets were obtained by applying each of the coating compositions on a support in an amount of lOg/m by dry weight in the same manner as in Example 1. All of the coating composition exhibited the same mechanical and thermal stability as in Example 1.
• EXAMPLE 4 A coating composition was obtained in the same procedure as in Example 1 except that 5 parts of zinc stearate were further added in the incorporation of 100 parts of Nikanol S100 and parts of zinc 3,5-di(a,adimethylbenzyl) salicylate.
• a sensitized sheet was obtained from the coating composition in the same manner as in Example 1.
• EXAMPLE I00 parts of a-methylstyrene polymer with a molecular weight of about 1100 were heated at about 180C together with parts of zinc stearate and 60 parts of zinc 3- ⁇ 4'-(a,a-dimethylbenzyl) phenyl ⁇ -5-(a,adimethylbenzyl) salicylate, melted and incorporated in. The resultant was cooled, solidified and coarsely crushed. All of the crushed products were incorporated with 40 parts of a powdered zinc silicate, parts of polyacrylamide (degree of polymerization, about 1000) and 500 parts of water and pulverized in a porcelain ball mill for about 20 hours. Finally, 60 parts of a styrene-butadiene polymerization latex were added thereto to form a coating composition.
• a sensitized sheet was obtained from the coating composition in the same procedure as in Example 1.
• the coating composition exhibited a good mechanical and thermal stability during the coating work.
• EXAMPLE 6-l 6-14 100 parts of a novolak type p-phenylphenolformaldehyde polycondensation product (molecular weight, about 800) were incorporated into and melted with 150 parts of each of the organic acid substances as indicated hereunder at temperatures of 100 200C. A mass was obtained by cooling and solidifying the resulting liquid.
• Example No. Organic acid substances Zinc 4-octoxylhenzoate Zinc 3 phenyl salicylate 4-tertiary-butylbenzoic acid Zinc 5-(3'-carboxy 4'-hydroxybenzy
• Example 2 200 parts of each of the powdered substances were incorporated with 50 parts of zinc oxide, 600 parts of water and 40 parts of a soluble starch and pulverized in a sand grind mill. Finally, 100 parts of a carboxylated styrene-butadiene copolymer latex (solids, 50%) were added to form a coating composition. A sensitized sheet was obtained by applying the coating composition on a support in the same manner as in Example 1. Each of the coating compositions exhibited the same mechanical and thermal stability as that of Example 1.
• EXAMPLE 7 100 parts of polystyrene with a molecular weight of about 1000, 50 parts of aluminum 3-(a,a-dimethylbenzyl) -5-cyclohexylsalicylate and 300 parts of kaolin were heated at 180C, melted and incorporated in. A mass was obtained by cooling and solidifying the resul- 18 tant. The mass was coarsely crushed, then incorporated with 520 parts of an aqueous solution containing 20 parts of polyvinyl alcohol and pulverized in a ball mill for 20 hours. Finally, 20 parts of a styrene-butadiene copolymer latex (solids, 50%) were added to form a coating composition.
• a styrene-butadiene copolymer latex solids, 50%
• a sensitized sheet was obtained from the coating composition in the same procedure as in Example 1.
• the coating composition exhibited the same mechanical and thermal stability as that of Example 1.
• EXAMPLE 8 100 parts of a-methylstyrene polymer with a molecular weight of about 1000, 50 parts of 3-cyclohexyl-5- (a,a-dimethylbenzyl) salicylic acid, 3 parts of stearic acid and 30 parts of zinc oxide were heated at 170C, melted and incorporated in. The resultant was cooled and solidified to form a mass. The mass obtained was coarsely crushed, added with 500 parts of an aqueous solution containing 20 parts of starch and then pulverized in a ball mill for 10 hours. Finally, 50 parts of a styrene-butadiene copolymer latex (solids, 50%) were added to form a coating composition.
• a styrene-butadiene copolymer latex solids, 50%
• a sensitized sheet was obtained from the coating composition in the same procedure as in Example 1.
• the coating composition exhibited the same mechanical and thermal stability as that of Example 1.
• EXAMPLE 9 100 parts of polystyrene with a molecular weight of about 2000 obtained by a polymerization in carbon tetrachloride and 100 parts of aluminum 3,5-di( a-methylbenzyl) salicylate were incorporated and melted at about 150C, then cooled and solidified. The mass obtained was crushed to granules with a particle size of less than about 1000 ;1., added with 400 parts of kaolin and 100 parts of zinc oxide, and pulverized in a ball mill for 10 hours. All of the milled products were dispersed in a solution consisting of 200 parts of water, 800 parts of ethanol and 100 parts of ethylcellulose to form an ink composition.
• a sensitized sheet was obtained by printing the ink composition on a support with a weight of 50 g/m in an amount of 7 g/m by dry weight using the usual printing machine.
• EXAMPLE 10 100 parts of a styrene allylalcohol copolymer (monomer weight ratio l0, molecular weight about 3,000) and 200 parts of zinc 3,5-di-(a-methylbenzyl) salicylate were dissolved in 200 parts of acetone. The acetone was, then, evaporated to obtain a mass. The mass was coarsely crushed to a particle size of about 200 a, and 200 parts of the crushed products were incorporated with 1 part of Demol-N (see Example 2), 600 parts of water and 20 parts of a soluble starch and pulverized in a grinder (sold as Attritor by Mitsui Miike Seisakusho, Japan). Finally, 40 parts of styrene-butadiene copolymer latex (solids, 50%) were added to form a coating composition.
• styrene-butadiene copolymer latex solids, 50%
• a sensitized sheet was obtained with use of the coating composition in the same manner as in Example 1.
• EXAMPLE 1 l parts of a styrene-allylalcohol copolymer (monomer weight ratio 85 l5 molecular weight about 1500) and 300 parts of zinc 3 ,S-di-(a-methylbenzyl) salicylate were dissolved in 300 parts of acetone.
• the solution 19 obtained thus was little by little added to a dispersion consisting of 2500 parts of water, 30 parts of Demol-N and 500 parts of kaolin while stirring whereby a dispersion of a particulate substrate consisting of the styreneallylalcohol copolymer and zinc 3,5-di-(a-methylbenzyl) salicylate was obtained.
• a sensitized sheet was obtained by applying the dispersion on a support of 50 g/m in weight in an amount of 7 g/m by dry weight.
• EXAMPLE 12 To 200 parts of a polystyrene emulsion (solids, 50%) were added 100 parts of a 30% aqueous solution of sodium 3-(a,a-dimethylbenzyl)-5-methyl salicylate, heated to a temperature of 80C and added little by little with 500 parts of a 40% aqueous solution of stannous chloride while stirring. Thereafter, stirring was further effected for about one hour while maintaining a temperature the solution at 90C.
• the emulsified polystyrene particles obtained herein contain tin 3-(a,adimethylbenzyl)--salicylate.
• 150 parts of kaolin, 100 parts of water and 30 parts of a soluble starch were added to the above emulsion while vigorously stirring whereby a coating composition was obtained.
• a sensitized sheet was obtained with use of the coating composition in the same procedure as in Example 1.
• EXAMPLE 13-1 l3-9 100 parts of zinc' 3,5-di(ot-methylbenzyl) salicylate were incorporated in and melted with 50 parts of each of the organic high molecular compounds as indicated hereunder. The resultant was cooled and solidified, thus a mass being obtained.
• a sensitized sheet was obtained by applying each of the above dispersion on a support of 50 g/m in weight in an amount of 7 to 10 g/m by dry weight according to the same procedure as in Example 1.
• micro-capsules enveloping a color former therein was prepared.
• the micro-capsules may be prepared in accordance with, for example, US. Pat. No. 2,800,457. An embodiment for the preparation is given hereunder.
• the dispersion was cooled to 10C to allow a coacervate film to gel and added with 10 parts of formaldehyde. After ageing for 10 hours a capsule dispersion was formed. An upper sheet was obtained by applying the dispersion on a support paper of 50 g/m in weight in an amount of 5 g/m by dry weight.
• sensitized sheets of the invention were confirmed by the manners to follow.
• a sensitized sheet subjected to the treatments as mentioned hereunder and a sensitized sheet not subjected respective were placed under an upper sheet carrying the encapsulated color former in such a way that the coated surface is in contact with the micro-capsules, and a marking pressure by means of a typewriter was applied.
• Stabilities of color-forming ability toward heat, light and moisture were observed by differences in density of a developed color image between the treated and untreated sheets a. Allowing a sensitized sheet to stand in surroundings of a relative humidity and temperature of 50C for 10 hours.
• the upper sheet was placed over the sensitized sheet in such a way that the coated surface and the micro-capsules are opposite to each other, and
• 'a marking pressure by means of a typewrlter was ap- A f h b t t d h t w A 5 plied.
• a 10 r t f 10 h r d heet has low resistance toward water the pe uie or m f h h f d b.
• t t ere anses t e Sm] ge c.
• a process for the production of a sheet material for use in a pressure-sensitive copy system which comprises applying on a support sheet a suspension of a particulate mixture comprising (a) 100 parts by weight of an acidic organic substance selected from the group consisting of aromatic carboxylic acids and polyvalent metal salts thereof, and (b) from 5 300 parts by weight of an organic high molecular compound selected from the group consisting of polystyrene, styrene copolymers, a-methylstyrene polymer, a-methylstyrene copolymers, polyvinyl chloride, vinylchloride copolymers, vinylidenechloride copolymers, polychloroprene, cyclopentadiene polymers, cyclopentadiene copolymers, acrylic ester polymers, acrylic ester copolymers, acrylic acid copolymers, methacrylic ester polymers, methacrylic ester copolymers, methacrylic acid copolymers, vinylacetate poly
• said suspension further contains at least one of a water-insoluble inorganic ma terial, in form of particles, selected from the group consisting of inorganic metal compounds and mineral pigments.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Color Printing (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Heat Sensitive Colour Forming Recording (AREA)
• Discharging, Photosensitive Material Shape In Electrophotography (AREA)
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Citations (3)

• 1972
  • 1972-09-27 JP JP9743072A patent/JPS551195B2/ja not_active Expired
• 1973
  • 1973-09-18 NO NO3647/73A patent/NO139432C/no unknown
  • 1973-09-25 ZA ZA737561*A patent/ZA737561B/xx unknown
  • 1973-09-25 FI FI2985/73A patent/FI59362C/fi active
  • 1973-09-25 CA CA181,863A patent/CA997146A/en not_active Expired
  • 1973-09-25 FR FR7334359A patent/FR2200785A5/fr not_active Expired
  • 1973-09-25 AT AT822673A patent/AT334929B/de not_active IP Right Cessation
  • 1973-09-26 NL NLAANVRAGE7313235,A patent/NL175601C/xx not_active IP Right Cessation
  • 1973-09-26 SE SE7313139A patent/SE413646B/sv unknown
  • 1973-09-26 DK DK526173AA patent/DK139901B/da not_active IP Right Cessation
  • 1973-09-26 BE BE136061A patent/BE805336A/xx not_active IP Right Cessation
  • 1973-09-27 MX MX146416A patent/MX150204A/es unknown
  • 1973-09-27 BR BR7548/73A patent/BR7307548D0/pt unknown
  • 1973-09-27 YU YU2559/73A patent/YU36883B/xx unknown
  • 1973-09-27 DE DE2348639A patent/DE2348639C3/de not_active Expired
  • 1973-09-27 US US401552A patent/US3924027A/en not_active Expired - Lifetime
  • 1973-09-27 IT IT29468/73A patent/IT993457B/it active
  • 1973-09-27 CH CH1386173A patent/CH586610A5/xx not_active IP Right Cessation
  • 1973-09-27 GB GB4524673A patent/GB1445866A/en not_active Expired
  • 1973-09-27 ES ES419129A patent/ES419129A1/es not_active Expired

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