US3834929A

US3834929A - Color developer sheet for pressure sensitive recording paper

Info

Publication number: US3834929A
Application number: US00208894A
Authority: US
Inventors: H Kato; T Hayashi; S Ishige
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1970-12-26
Filing date: 1971-12-16
Publication date: 1974-09-10
Anticipated expiration: 1991-09-10
Also published as: IE36855B1; JPS521329B1; ES397920A1; CA948496A; DE2163905A1; AU3660671A; IE36855L; AU465050B2; GB1350011A

Abstract

A COLOR DEVELOPER SHEET FOR PRESSURE SENSITIVE RECORDING PAPER COMPRISING A COLOR DEVELOPER LAYER CONTAINING A METALLIC COMPOUND OF A PHENOL COMPOUND, SAID PHENOL COMPOUND PKA BELOW 8.

Description

United States Patent 3,334,929 COLOR DEVELOPER SHEET FOR PRESSURE EENSITIIVE RECORDING PAPER Takao Hayashi and Hajime Kato, Fujinomiya, and Sadao Ishige, Minami Ashigara, Japan, assignors to Fuji Photo Film (10., Ltd., Kanagawa, Japan N0 Drawing. Filed Dec. 16, 1971, Ser. No. 208,894

Claims priority, application Japan, Dec. 26, 1970,

45 118,97 8 Int. Cl. B41m /22 U.S. Cl. 117-362 7 Claims ABSTRACT OF THE DISCLOSURE A color developer sheet for pressure sensitive recording paper comprising a color developer layer containing a metallic compound of a phenol compound, said phenol compound pKa below 8.

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a color developer sheet for pressure sensitive recording paper. More particularly, the present invention relates to a color developer sheet for pressure sensitive recording paper using a metallic phenol compound which is a metal phenolate and which has not hitherto been used as a color developer.

Description of the Prior Art Pressure sensitive recording papers utilize the reaction of a colorless organic compound (hereinafter referred to as a color former) and a color developing material (hereinafter referred to as a color developer) capable of reacting with the above color former to form a colored product.

Usually pressure sensitive recording papers are composed of a sheet (color former sheet) having coated thereon microcapsules containing a solution of color former in an organic solvent and a sheet (color developer sheet) having coated thereon a color developer with a binder, and may include a sheet having coated on one side a color developer and on the other side the microcapsules (such assemblies are hereinafter referred to as pressure sensitive duplicating papers). Sheets are also formed having microcapsules and the color developer on the same side of the support (called single recording paper).

As color formers, malchite green lactone, benzoyl leucomethylene blue, crystal violet lactone, Rhodamin B lactam, 3-dialkylamino-7-dialkylamino fluoranes, 3-alkyl- 2,2-spiro bi(benzo f Chromene), etc. have been used.

As color developers, there have been used clays such as acidic clay, attapulgite, kaoline, geolite, pyrophilite, bentonite, haloycite, and phenol compounds such as pcresol, p-phenyl phenol, pentachlorophenol, pentamethylphenol, p,p'-biphenol, 5,5 diethyl-o,o-biphenol, 2,2- rnethylene bis (4-chlorophenol), 4,4-thiodiphenol, etc. as described in the specification of Japanese Pat. 465,300. However, clays such as acidic clay and active clay are usually employed.

Conventional color developers using clays tend to adsorb materials from the air at the active point of the clay when allowed to stand in air, and remarkably lower in color developing ability. Though color developer clays have a higher color developing ability than that of other color developers (p-cresol, p-phenylphenol and the like), the color developing ability thereof is lowered when it is exposed to sun-light. In addition, the colored body on the color developer sheet has the defect that when wet with water the color disappears or is lowered in concentration.

The color developer sheets using the above described phenol compounds cannot be used as a practical matter since although they have good water proofness as a colored body on the sheet, they are low in color developing ability, which is most important and also is poor in light resistance of the colored body 011 the sheet.

SUMMARY OF THE INVENTION The present inventors have found that by using a metallic phenol compound as a color developer a color developer sheet which is high in color developing ability, good in water resistance as a colored body and exhibits less lowering of activity can be obtained. The object of the present invention is thus to provide a color developer sheet for pressure sensitive duplicating papers which meets the above criteria and does not have the substantial defects of the prior art color developer.

DETAILED DESCRIPTION OF THE INVENTION The metallic compound of phenol used in the present invention is obtained by reacting an alkali metal salt of a phenol compound and a water soluble metallic salt in a solvent. In this case, the alkali metal salt of the phenol compound and the water soluble metallic salt can be used at any ratio, although the water soluble metallic salt is preferably used in an amount greater than 1 gram equivalent per gram equivalent of the alkali metal salt of the phenolic compound.

The reaction can be attained by adding an aqueous solution of a water-soluble metal compound to an aqueous solution of alkali metal salt of phenol compound. The addition of the compounds may be carried out in reverse order, of course. 7

The metal compound of phenol is immediately produced. In the reaction, reaction condition such as temperature or pressure are of no importance, and the reaction proceeds at normal condition.

Various methods are known for synthesizing the alkaline salts of such phenol compound or aqueous solutions thereof. For example, one method of obtaining an alkali salt of phenol or its aqueous solution is by reacting the base phenol compound with an alkali metal, a hydroxide or carbonate of the alkali metal in an amount of one gram equivalent or more of the above hydroxide or carbonate per one gram mole of the alkali salt of phenol. Other methods may, of course, be used, but the above method is very simple.

As the phenol compound used to form the metal compound of a phenol compound in the present invention phenols having pKa of below 8 such as 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol, pnitrophenol, p-methylsulfonyl-phenol, methylsulfonyl phenol, 4-phenyl sulfonyl phenol, 4-cyanophenol, 2,4-dicyanophenol, 4- cyano-Z-chlorophenol, 2,4-dichloro-4-cyanophenol, tetrachloro-bis phenol A, 4,4-dihydroxy-3,3'-dichlorodiphenylsulfone, 4,4 dihydroxy 3,3',5,5'- tetrachlorodiphenyl sulfone, etc. are effective.

The present inventors have tried to synthesize a metallic phenol compound from a phenol compound above 8 in pKa. However, a phenol compound of above 8 in pKa does not make a metallic compound as shown by the infra-red absorption curves and the color developing ability of the product. These are not different from those of the phenol monomer compound itself. Herein, pKa=log (acidity constant).

As water soluble metallic salts used in the present ine as chromium, molybdenum, etc., Group VIIb metals such as manganese, etc., and Group VIII metals such as cobalt, nickel, etc.

Among these, the water soluble salts of zinc, nickel, manganese, copper, magnesium, calcium, are particularly preferred. As representative water soluble metallic salts inorganic salts such as chlorides, sulfates, nitrates, etc. and organic salts such as acetates, oxalates, etc. of the above described metals can be employed.

To manufacture the color developer sheet of the present invention, at least one metallic phenol compound produced by the reaction of the above described alkaline phenol salt and the above described water soluble metallic salt (either in the form of a reaction mixture or, preferably, after it has been separated and purified) is coated with a binder onto a support such as paper, synthetic paper etc., in an amount of above 0.1 g./m. desirably 0.2 to 5 g./m. The upper limit of the coating amount is primarily determined by reasons of economy and coating workability.

The binder is not necessarily used (that is, the metallic phenol compound is dissolved for use as an ink), but if it is used, the amount thereof is preferably from about 5 to about 50 parts by weight, preferably parts by weight, based on 100 parts by weight of the metallic phenol compound. Those skilled in the art will appreciate these figures can vary.

As the medium for applying the color developer of the present invention, water or various organic solvents can be used alone or in any mixing ratio. The organic solvents used include methanol, ethanol, butanol, acetone, n-butyl acetate, benzene, toluene, methylene chloride, etc.

As the binder, cellulose derivatives such as nitrocellulose, natural or synthetic polymers such as vinyl acetate, vinyl chloride, polyamide, polyacrylic acid, styrenebutadiene copolymer, casein, polyvinyl alcohol, gelatine, gum arabic, etc., latexes such as styrene-butadiene latex, butadienemethylmethacrylate latex, etc. are primarily employed. Essentially any polymeric binder used in the prior art can be used for the same purpose in the present invention.

The color developer sheet using the color developer of the present invention may be used in combination with a color former sheet and there may be arranged thereon a rnicrocapsule layer containing a color former. The color developer of the present invention may also be mixed with the microcapsules and coated onto a support, for example, a paper. Furthermore, as another method of use, a color developer ink containing the above compound can be printed onto a paper by a printing process.

The color developer sheet using the color developer of the present invention has the following excellent effects in comparison with the conventional color developer sheet using clays such as acidic clay, etc.

Clay paper is remarkably lowered in color developing ability when it is allowed to stand in a room and the color developer sheet of the present invention is greatly improved at this point.

Further, although almost all colored material on a conventional clay paper disappears or is lowered in color concentration upon wetting with water, the colored material on the color developer sheet of the present invention is not lowered in concentration even if wet with water. In addition, for the case of manufacturing a color developer sheet according to the present invention, sufficient color developing ability and other properties necessary for a color developer sheet for pressure sensitive recording paper are satisfied with a smaller amount of coating than in conventional clay paper. That is, conventional clay paper requires a coating amount of 7 to 10 g./m. while the color developer of the present invention is suffi cient at a coating amount of 0.2-5 g./m. Thus, a small amount of coating is sufiicient and the physical properties of the coating liquid can be freely varied in a manner impossible with clay coatings.

Furthermore, when coating the color developer onto a paper previously coated with a natural or synthetic high molecular weight substance or a repellent, the same color developing ability can be obtained with smaller amount of coating.

Finally a color developer sheet using a metallic phenol compound is remarkably higher in color developing ability and in light fastness of the colored material formed up on the color developer sheet, as compared to a color developer sheet using a phenol compound per se as a color developer.

The present invention will be illustrated in great detail by the following Examples which, of course, are not to limit the present invention, where all parts are by weight unless otherwise indicated.

The effect of the color developer sheet of the present invention was confirmed with the following color former sheet. The microcapsules containing color former were manufactured according to U.S. Pat. 2,800,457, using the following procedure.

10 parts of acid treated pig skin gelatin and 10 parts of gum arabic were dissolved in 40 parts of water at 40 C. and 02 part of Turkey red oil was added thereto as an emulsifier, whereafter 40 parts of color former oil were emulsified and dispersed therein. The color former oil was 2% crystal violet lactone dissolved in an oil consisting of 4 parts of chlorinated diphenol and 1 part of kerosene. Emulsification was stopped when the oil droplet size was an average of 5 microns. 900 parts of water at 40 C. was added thereto and stirring was continued. At this time care must be taken so that the liquid temperature does not fall below 40 C. Then 10% acetic acid was added thereto to adjust the pH of the liquid to 4.0 to 4.2, resulting in coacervation. The stirring was continued further and, after 20 minutes, the system was cooled with ice to gel the coacervate film deposited around the oil droplets. When the liquid temperature reached 20 C., 7 parts of 37% formaldehyde were added thereto and, at 10 C., a 15% aqueous solution of caustic soda was added to adjust the pH to 9. The addition of caustic soda should be carried out at 10 C. to obtain the best results. The liquid temperature was then raised to 50 C. with stirring for 20 minutes. The microcapsule, thus obtained were conditioned at 30 C. and thereafter directly coated onto a 40 g./m. paper to a 6 g./m. solids content, and dried. And in case of other color former the recording paper was manufactured in the same manner as described above.

Example 1 0.01 g. equivalent of caustic soda was dissolved in 30 ml. of warm water and 0.01 g. equivalent of phenol compound (see Table 1) was dissolved therein. 0.01 g. equivalent of the below described water soluble metallic salt dissolved in 10 ml. of warm water was then added to this solution with stirring.

Crystals immediately precipitated out. The crystals were filtered and washed with water several times and dried.

The product obtained by the above method Was dissolved or dispersed in 30 ml. of ethanol to obtain a coating liquid. This coating liquid was coated onto a 40 g./m. paper by a glass tube at a solid content of 0.5 g./m. and dried to obtain a color developer sheet.

Comparative Example 1 3 g. of phenol compound per se were dissolved in 30 ml. of ethanol and the resulting ethanol solution was coated on a 40 g./rn. paper by a glass tube at solids content of 0.5 g./m. and dried to obtain a color developer sheet.

Example 2 0.01 g. equivalent of caustic soda was dissolved in 30 ml. of warm water and 0.01 g. equivalent of phenol compound was dissolved therein. 0.01 g. equivalent of the below described water soluble metallic salt dissolved in 10 ml. of warm water was added to this solution with stirring.

Furthermore, 0.5 g. of the below described binder dissolved in ml. of warm water was added thereto to obtain a coating liquid. This liquid was coated onto a paper at a solids content of 0.5 g./m. and dried to obtain a color developer sheet.

6 ability for crystal violet lactone and 3-dibenzylamino-7- diethyl aminofluorane color formers and, in addition, in the light fastness of the colored body in comparison with using only a phenol compound as a color developer. The colored body produced in accordance with the present invention was not lowered in color concentration even if Test results wetted with water.

(1) The color developer sheet of Example 1 and Com- 'For other color formers the same results were obparative Example 1 were color developed by stocking tained. In the color developer sheet of the present inpaper coated with microcapsules containing crystal violet 1O vention in Example 2, as shown in Table 2, the color lactone thereon (heretofore described) and applying a developing ability for crystal violet lactone and 3-di- 600 leg/cm. load thereto. After standing at a dark place benzylamino-7-diethylamino-fiuorane color formers was for 1 hour, the spectral absorption curve in the 700 to high, and the light fastness of the colored body was high. 400 m wave length region was measured and the con- In addition, the colored body was not lowered in color centration at the maximum absorption (wave length 610 concentration even if wetted with water.

TABLE 2 Light fast- Color con- Light fastness ness of centration of of colored colored 3-dlibcnzy1- body 01'3- body of amino-7- dibenzylamino- Color concrystal diethyl- 7-diethylcentration of violet amino amino Water soluble crystal violet lactone Iluorane fiuorane Phenol compound metallic salt Binder lactone (D1) (percent) (D 1) (Percent) Example 2. Pentachlorophenol Zinc sulfate Polyvinyl alcohol. 0.897 60 0.648 97 Do do Magnesium sulfate ..do 0. 953 73 0.651 94 Do do Tin chloride Gum arabic... 0.498 55 0.436 83 Do. 2,4,6-trichlorophenol. Nickel sulfate Sodium alginate 0.542 47 0.477 85 Do 2,4-dicyanophenol Manganese chloride do 0.625 52 0.542 81 Do 4-pheny1sulfonylphenol Copper sulfate Gum arabic 0.551 50 0. 524 76 m was taken as the fresh concentration. After irradia- Example 3 F g i i gg gg i z g i 355g: 1 5 33333 parts of ethyl cellulose were homogeneously disve n at th nfaxim absor fion Wave len th solved in a mixed solution of 15 parts of dibutyl phthalate, gfa fg m 10 e L p g 100 parts of ethylacetate, 90 parts of butyl acetate, 80

parts of isopropyl alcohol and 60 parts of butanol, and b g fi g ig l g gi fg fi value defined 120 parts of the zinc salt of pentachlorphenol was mixed Y e g q S 3;) into this solution and completely dissolved or dispersed Light fastness value by means of a ball mill to obtain a white suspension of color developing ink. The ink was diluted with a mixed tm xim m losor tion Concentmmon i n p S nu ht solvent of ethyl acetate and ethanol (1:1) so that the 1 a 1 10 W1 u 100 40 viscosity was about 0.7 poise, and printing was conducted Flesh concentration at maximum absorption by the flexo printing method to give a 3 2 dried To measure the spectral absorption curve a Beckmann film. spectroscope Type DB (manufactured by Toshiba Co.) Thus obtained developer sheet was contacted with a was d color former sheet same as in the former Examples to (2) A color developer sheet coated with a microcapbtam the similar results. sule containing 3 dibenzylamino-7-diethylaminofluorane What is claimed is: was color developed in the same manner and, after stand- 1. A pressure-sens1t1ve recording sheet which comprises ing in a dark place for 1 hour, the spectral absorption 21 color developer layer capable of reacting with a color curve in the 700 to 400 m wave length region was former t0 form acolof Productcomprising! measured, and the concentration at the maximum aba support sheet having coated thereon the color desorption (wave length 600 mg) was taken as fresh conveloper layer containing a metal phenolate, said centration. Further, after irradiation with sun light for 2 ph nolate having a pKa value of below 8 and being hours, the spectral absorption curve of the colored body Capa l f reacting with the color former to form was measured to obtain the concentration at the maxi- Said Color product. mum absorption (Wave length 530 me). The light fastsaid metallic member of said metal phenolate being a nesswas obtained in the same manner as in(l). metal belonglng to a member t d fr m th TABLE 1 Light fastness of Color concencolored body of Color con- Light fastness tration of 3- 3-dibenzylcentration of colored body dibenzylamiamino-7-diof crystal of crystal no-7-diethylcthylamino- Water soluble violet lacviolet laetonc aminofiuorane fluorane Phenol compound metallic salt o i) (P i) (percent) Example 1 Pentachlorophenol. Zinc chloride 0.889 66 0.650 102 Do 2 pentachloropheno 0.907 61 0.652 99 Do do 0. 739 48 c. 691 86 Do do Magnesium sl11fate- 0. 961 0.662

Do .do Manganese chloride. 0.770 69 0. 663 108 Do do Nickel sulfate 0.873 75 0.647 109 Comparative Example 1. .do 0. 164 Disappearance 0. 155 Disappearance Example 1 2,4,6-trichlorophen0L. 0. 530 42 0. 453 82 Comparative Example 1 o 0.061 Disappearance 0.056 Disappearance Example 1 2,4-dichlorophenol 0.516 45 0.435 85 Comparative Example 1- o 0.052 Disappearance 0.048 Disappearance Example 1 2,4-dichloro-4-cyanophenol Manganese suliate 0.643 54 0.566 9 Comparative Example 1 ..do 0. Dlsappearance 0.119 Disappearance The color developer sheet of the present invention was thus formed to be remarkably higher in color developing group consisting of Group Ib, Group Ila, Group IIb, Group IIIa, Group IVa, Group VIb, Group VIII) and Group VIII of the Periodic Table.

2. A pressure-sensitive recording sheet as claimed in Claim 1 wherein said metal phenolate is obtained by reacting an alkali metal salt of a phenol compound and a water soluble metallic salt.

3. A pressure-sensitive sheet as claimed in Claim 2 where the water soluble metallic salt is used in an amount greater than 1 gram equivalent per gram equivalent of the alkali metal salt of the phenol compound.

4. A pressure-sensitive recording sheet as claimed in Claim 1 wherein the phenol compound utilized to provide said metal phenolate is a halophenol, a nitrophenol, an alkylsulfonyl phenol, an arylsulfonyl phenol, a cyanophenol, a halocyano phenol, a bisphenol, a hydroxyhalophenylsulfone.

5. The pressure-sensitive recording sheet of Claim 1, wherein said metal is a member selected from the group consisting of zinc, nickel, manganese, cobalt, magnesium and calcium.

6. The pressure-sensitive recording sheet of Claim 1,

wherein said color former is present in a color former sheet different from said support sheet having coated thereon said color developer layer.

7. The pressure-sensitive recording sheet of Claim 1, wherein said color former is present in said color developer layer.

References Cited UNITED STATES PATENTS 3,592,677 7/1971 Tsuboi et a1. 1l7-36.8 3,079,270 2/1963 Cortez 117-154 2,680,097 6/1954 Stewart 260-621 F 2,579,329 12/1951 Martin 260621 P WILLIAM D. MARTIN, Primary Examiner W. R. TRENOR, Assistant Examiner US. Cl. X.R.