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

• ABSTRACT A recording sheet which comprises a layer of a color developer which forms a color image upon contact with a color coupler, said layer containing at least one metal compound of an aromatic carboxylic acid and a surface active agent is disclosed.
• This invention relates to a recording sheet. More particularly, it relates to a recording sheet wherein an improved color developer is used.
• color former an electron denoting colorless organic compound capable of forming a distinct color when contacted with an acid (hereinafter called color former) such as Malachite Green Lactone, Benzoyl Leuco Methylene Blue, Crystal Violet Lactone, Rhodamine B-Lactam, 3-diaIkylamino-7-dialkylaminofluorane and 3-methyl-2,2-spirobi( benzol(f)cumene) with a solid acid substance which develops a color in contact with the color former (hereinafter called color developer) is used.
• color developer a solid acid substance which develops a color in contact with the color former
• the coloring reaction with the color coupler requires pressure from a pen or typewriter, heat or some other physical modification to initiate the reaction.
• Pressure sensitive copying papers are typical examples of such recording sheets.
• a pressure sensitive copying paper is obtained by dissolving a color coupler in a solvent such as an alkylated naphthalene, alkylated diphenyl or alkylated diphenylmethane, dispersing the solution in a binder or encapsulating it in microcapsules, and then coating the dispersion or microcapsules on a support such as paper, plastic film or resin-coated paper.
• a solvent such as an alkylated naphthalene, alkylated diphenyl or alkylated diphenylmethane
• a heat sensitive copying paper is obtained by coating a color coupler together with a heat-fusible substance such as acetanilide on a support.
• a heat-fusible substance such as acetanilide
• the term heat-fusible substance means a substance which is fused upon heating and solves the color coupler.
• a color developer is usually dissolved or dispersed with a binder in water or an organic solvent and coated on or impregnated into a support.
• the color developer may also be so coated or impregnated just before recording.
• the color coupler and color developer are each coated on the same or opposite surfaces of a support or on different supports, respectively.
• clays such as Japanese acid clay, activated clay, attapulgite, zeolite and bentonite; organic acids such as succinic acid, tannic acid, gallic acid and phenol compounds; and acid polymers such as phenol resin.
• the phenol resins do not have sufficient color devel oping power, and their colored images show poor light fastness though they are excellent in water stability on reacting with a color coupler.
• a colored image obtained from a phenol resin and Crystal Violet Lactone discolors easily not only on exposure to light but on standing in a room, and the surface of the phenol resin which has not undergone reaction (color development) turns yellow.
• acid polymers such as, for example, maleic acid-rosin resin or partially or wholly hydroylsed styrene-maleic anhydride copolymers inherently have a low color development power and can not be used practically.
• a metal compound of an aromatic carboxylic acid was effective as a color developer for recording sheets. That is, the performance of a color developer can be substantially improved using a metal compound of an aromatic carboxylic acid.
• the color development power and the film surface strength of a coated layer formed from such a system are not always sufficient (depend ing on the conditioning of the color developer coating solution), leaving room for improvement.
• one object of this invention is to provide a recording sheet of improved color development power and film surface strength.
• a second object of this invention is to improve the coatability of coating solutions used in the manufacture of a recording sheet of improved color development power and film surface strength.
• the metal compound of an aromatic carboxylic acid can be used as a color developing component alone because it has a color development power itself, it can also be used together with other color developers.
• the coating solution containing a metal compound of an aromatic carboxylic acid can be prepared by dissolving or dispersing at least one metal compound of an aromatic carboxylic acid in a solvent.
• the solvent which can be used. in the invention includes water, an organic solvent and other liquid media for an aromatic carboxylic acid, a metal salt, and a metal compound of aromatic carboxylic acid.
• the most preferred solvent to be used in the present invention is water. If a surface active agent is not added thereto, the viscosity of the prepared coating solution increases in the course of preparation and, occasionally it cannot be coated.
• alkylnaphthalene sulfonates represented by the formula higher alcohol phosphates represented by the formula ROP(0X) naphthalene sulfonate-formalin condensates represented by the formula wed polyoxyethylene alkylsulfonates represented by the formula R(OC H ),,OSO X.
• R+R has I to 30 carbon atoms, preferably 8 to 20 carbon atoms, R, is a methylene group in such a manner that total carbon atoms of R and R are l to 30, preferably 8 to 20, m is an integer of 2 to 10, preferably 6 to 9, n is an integer of l to 6, and X is an alkali metal such as Na or Ka, or an ammonium group; cationic surface active agents such a tertiary amines and ethanolamine ester salts; nonionic surface active agents such as glycerine mono-fatty acid esters and sugar fatty acid esters; and mixtures thereof.
• anionic surface active agents show a great effect and alkylbenzene sulfonic acid salts, higher alco hol sulfuric acid ester salts, naphthalene sulfonic acid salt-formaldehyde condensates and alkarylsulfonic acid salts are most preferred.
• the amount of surface active agent added is more than 0.5 parts by weight, preferably 1 to 20 parts by weight, per parts of the metal compound of an aromatic carboxylic acid.
• the coating solution which is prepared as described above, may contain 5 to 50 parts by weight of a binder such as latex, polyvinyl alcohol, maleic anhydridestyrene copolymer, starch and gum arabic, per [00 parts by weight of coating solution (solids content).
• a binder such as latex, polyvinyl alcohol, maleic anhydridestyrene copolymer, starch and gum arabic, per [00 parts by weight of coating solution (solids content).
• the binders can be classified into three groups, i.e., (l) a water soluble or hydrophilic binder, for example, a natural compound such as proteins (e.g., gelatin, gum arabic, colloid albumin, casein), celluloses (e.g., carboxymethyl cellulose, hydroxyethyl cellulose), saccharoses (e.g., agar, sodium alginate, starch, carboxymethyl starch), and a synthetic compound such as polyvinyl alcohol, poly-N-vinylpyrrolidone, polyacrylate, polyacrylamide', (2) a water-dispersible binder, for example, latex such as styrene-butadiene copolymer latex, styrene-maleic anhydride copolymer latex; and (3) an organic solvent-soluble binder such as nitrocellulose, ethyl cellulose or polyester.
• a water soluble or hydrophilic binder for example, a natural compound such as proteins (
• binders can be used in the form of solution or dispersion in a solvent in the invention, and the binder can be varied depending upon the type of solvent.
• the water-soluble or dispersible binder can be used in the aqueous solution or dispersion.
• the metal compound of aromatic carboxylic acid can be coated without using the binder. it is to be noted that the binder is optional because it may not be necessary in case where the solvent is organic in nature.
• acid resins such as phenol-formaldehyde resin such as p-phenylphenol-formaldehyde resin, p-t-butylphenolformaldehyde resin, p-chlorophenol-formaldehyde resin, other color developers such as Japanese acid clay 5 erably 20 to 2,000 wt%, more preferably 500 to 1,000
• the metal oxide or hydroxide is generally used in an amount of from about 20 to 400 wt%, preferably 50 to 200 wt% based on the metal compound of aromatic carboxylic acid.
• the metal compound of an aromatic carboxylic acid is a salt of such an acid such as zinc, tin, aluminum, nickel, magnesium or calcium salt of an aromatic carboxylic acid, and these salts can be obtained easily by stirring an aromatic carboxylic acid or an alkali metal salt thereof with a metal hydroxide, sulfate or nitrate in the presence of an alkali.
• the pH value, temperature and pressure is not critical.
• the addition of surface active agent during or after the reaction of the aromatic carboxylic acid or its alkali metal salt with the metal salt results in a stable and effective preparation of the color developer coating solution.
• the aromatic carboxylic acid is preferably represented by the formula:
• R may be the same or different and represents a hydrogen atom, a hydroxy group, a halogen atom such as chlorine, a nitro group, an alkyl group having I to carbon atoms (preferably 3 to 6 carbon atoms), of which total carbon atoms are less than 13, an aryl group such as phenyl group, an arylamino group such as anilino group, and an alicyclic group such as hexyl group, m is an integer of 0 to 7 and n is an integer of 0 to 5, and the aromatic carboxylic acid may be dimerized through the substituent R as a methylene group.
• aromatic carboxylic acids having at least one hydroxy] group are especially effective and those having a hydroxyl group in the o-position, i.e., the aromatic carboxylic acids represented by the following formulae, are more effective.
• metals which form the metal compound of the aromatic carboxylic acid used in this invention there can be mentioned metals of Group [B of the Periodic Table as, e.g., copper and silver; metals of Group II A as, e.g., magnesium and calcium; metals of Group ll B, e.g., zinc, cadmium and mercury; metals of Group III B, e.g., aluminum and gallium; metals of Group IV A, e.g., tin and lead; metals ofGroup VIA, e.g., chromium and molybdenum; metals of Group Vll B, e.g., manganese; and metals of Group Vlll such as cobalt and nickel.
• metals of Group [B of the Periodic Table as, e.g., copper and silver
• metals of Group II A as, e.g., magnesium and calcium
• metals of Group ll B e.g., zinc, cadmium and mercury
• the resulting coating solution of color developer is coated on a support such as paper, synthetic paper or a synthetic resin film so that the amount of the metal compound of an aromatic carboxylic acid is more than 0,] glm preferably 0.5-2 g/m
• a support such as paper, synthetic paper or a synthetic resin film
• the recording sheet according to the invention is characterized by containing both a metal compound of an aromatic carboxylic acid and a surface active agent in the color developer layer, and various optional additives in the color developer layer, amount thereof, procedure of addition, form, kind of color coupler which couple with the color developers, their form and solvents for the same are decided using available technology in recording sheet art.
• the recording sheet according to this invention shows an excellent color developing power and the thickness of the coated layer can be minimized; therefore, a colored image of high density is formed directly on contact with a color coupler.
• the film surface (the surface of the coated layer) is stable before and after use because of its excellent film surface strength. Further, the viscosity of the coating solution is not raised in the process of manufacturing the recording sheet according to this invention so that coatability is improved. Accordingly, not only is size-press coating by on-machine carried out advantageously, but air-knife coating is performed easily. Such advantages result in a thin coated layer as well as a reduction in product cost.
• the recording sheet according to this invention is illustrated in detail by the following examples.
• the effect in the examples was determined by the combination of an upper paper where microcapsules containing a color coupler (prepared as described below) were coated on a support with a lower paper in which the color developer according to this invention was coated on a support.
• microcapsules containing the color coupler may be manufactured by various known methods, but here they were manufactured according to the US. Pat. No. 2,800,457 as follows. In the following examples, part means part by weight.
• the system was then heated for 20 minutes with stirring to raise the liquid temperature to 50C.
• the resulting dispersion of microcapsules was cooled to 30C and then coated so that the solids amount coated was 5 g/m on a paper of 40 g/m"'-, and dried to make a capsule sheet.
• EXAMPLE l 60 Parts of kaolin and 2 parts of a surface active agent as mentioned below were dispersed or dissolved, respectively, in 30 parts of water and the pH of the dispersion was adjusted to l0 by a aqueous caustic soda solution. 70 Parts of an aqueous l0% zinc chloride solution were added to the dispersion with slow stirring and a solution of 0.l g-equivalent of an aromatic carboxylic acid as mentioned below in 200 parts of an aqueous 2% caustic soda solution was added with stirring to cause reaction.
• SBR latex styrene-butadiene copolymer latex
• EXAMPLE 2 Parts ofJapanese acid clay, I part of sodium hexametaphosphate and 4 parts of a surface active agent as mentioned below were dispersed or dissolved in 300 parts of water and the pH adjusted with an aqueous l0% caustic soda solution to I0. 107 Parts of an aqueous 10% zinc sulfate solution were added to the dispersion with slow stirring and a solution of 0.1 g-equivalent of an aromatic carboxylic acid as mentioned below dissolved in 200 g of an aqueous 2% caustic soda solution was added with stirring to cause reaction. 50 Parts of SBR latex were added to the dispersion to prepare a coating solution, which was coated by means of coating rod so that a solids amount of 3 g/m was coated on a paper of 50 g/m and dried.
• EXAMPLE 3 A color developer sheet according to this invention was obtained in the same manner as in Example I using parts of an aqueous l0% tin sulfate solution instead of an aqueous zinc chloride solution as in Example 1.
• CONTROL 3 A color developer sheet was obtained for comparison in the same manner as in Example 3 without using the surface active agent.
• EXAMPLE 4 A color developer sheet according to this invention was obtained in the same manner as in Example 2 using 57 parts of an aqueous l0% aluminum sulfate solution instead of an aqueous zinc sulfate solution as in Example 2.
• CONTROL 4 A color developer sheet was obtained for comparison in the same manner as in Example without using the surface active agent.
• EXAMPLE 5 60 Parts of china clay, 5 parts of a p-phenylphenolformaldehyde condensate (passed 325 mesh; a mixture of condensates having a condensation degree of 2 to 10) and 2 parts of a surface active agent as mentioned below were dispersed or dissolved in 300 parts of water and the pH adjusted with an aqueous 10% caustic soda solution to ll. To the dispersion were added 70 parts of an aqueous 10% zinc chloride solution with slow stirring and a solution of 0.1 g equivalent of an aromatic carboxylic acid as mentioned below dissolved in 200 parts of an aqueous 2% caustic soda solution was added with stirring to cause reaction.
• a color developer sheet was obtained for comparison 5 l-5 and Controls l-S was determined and is shown in in the same manner as in Example 5 without using the Table l. The determination was carried out with a BL surface active agent. Type viscometer (60 rpm).
• Alkylphenol-Ethylene Oxide Adduct 9 Alkylphenol-Ethylene 30.5 0.96 0.76
• microcapsule sheet containing Crystal Violet Lactone or 3-benzylamino-7-diethylaminofluorane was placed in contact on each color developer-coated sheet of Examples l-5 and Controls l-5 and color developed 12 l5 5 by a pressure load of 600 Kg/cm.
• a recording sheet which comprises a layer of a color developer which forms a color image upon contact with a color coupler, said layer containing at least one metal compound of an aromatic carboxylic acid represented by the formula:
• R may be the same or different and represents a hydrogen atom, a hydroxy group, a halogen atom, a nitro group, an alkyl group having I to 10 carbon atoms, the total carbon number in the Rs being less than 13, an aryl group, an arylamino group or an alicyclic group, m is an integer of 0 to 7 and n is an integer of O to 5, or said aromatic carboxylic acid may be dimerized through the substituent R as a methylene group, and a surface active agent.
• a recording sheet according to claim I wherein the metal in said metal compound of an aromatic carboxylic acid is a member of Group I B, Group ll A, Group II B, Group Ill B, Group [V A, Group VI A, Group Vll B or Group VIII of the Periodic Table.
• a recording sheet according to claim 1 wherein said. surface active agent is an anionic surface active agent, cationic surface active agent or monionic surface active agent.
• a recording sheet according to claim 1 wherein said surface active agent is an anionic surface active agent.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Color Printing (AREA)

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Cited By (19)

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Citations (6)

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• 1972
  • 1972-07-14 JP JP47070498A patent/JPS527372B2/ja not_active Expired
• 1973
  • 1973-07-13 GB GB3363973A patent/GB1444962A/en not_active Expired
  • 1973-07-13 BE BE133484A patent/BE802344A/fr not_active IP Right Cessation
  • 1973-07-13 US US378859A patent/US3896255A/en not_active Expired - Lifetime
  • 1973-07-13 DE DE19732335747 patent/DE2335747A1/de active Granted
  • 1973-07-13 FR FR7325715A patent/FR2193357A5/fr not_active Expired

Patent Citations (7)

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