FR2547827A1 - Ink and eradicator for this ink - Google Patents

Abstract

Coloured ink comprising a developer containing a phenolic hydroxyl group, an electron-donor colourless dye which makes a colour appear under the action of the said developer, and a solvent which does not inhibit the colour development reaction, as well as an eradicator allowing the writing produced with this coloured ink to be eradicated, comprising a desensitiser compound which makes the said electron-donor dye colourless. The invention also relates to a set of instruments for writing 1, 5 and for eradicating 21, 25 with a storage container for ink 3 and a storage container for eradicating solution 23.

Description

 The present invention relates to a novel method of writing and erasing. More particularly, it relates to an ink coloring system colorless developer to obtain a dark and clean writing and an eraser or "eraser" to easily erase what has been traced with said ink. It also relates to an overall writing instrument using said ink and an eraser using said eraser.

 Various methods have already been developed for erasing ink writing. For example, there is (1) a method according to which the ink traced writing comprising an easily discolorable dye is erased by means of a bleaching agent and (2) a method according to which a dye is incorporated into a dye. In a high molecular weight rubbery material, the resulting material is dissolved in a solvent to obtain ink, and the traced writing of this ink is erased with a rubber. However, these methods have the following disadvantages. According to the method (1), the erased ink writing traces are capable of yellowing and the stability of the bleaching agent over time is poor.According to the method (2), since the viscosity of the bleaching agent is ink is greatly increased, it becomes necessary to use a pressurized ballpoint pen structure and, furthermore, the erasure efficiency does not seem absolutely satisfactory.

 It has already been proposed a writing method implementing a reversible reaction in which a color development is caused by an electron transfer between a developer having a phenolic hydroxyl group and a colorless electron donor compound (colorless dye) which acquires a color under the action of said developer, and this color development caused by the electron transfer is inhibited by a desensitizer consisting of a polar compound, which makes the colored dye colorless. For example, Japanese Patent Publication No. 21649/1973 discloses a typewriter composed of a dye (colorless dye) having in its molecule a developer component structure of a compound (developer) having an acidic hydroxyl group in its composition. This type of writing material is intended to provide a special-purpose ink which is colorless just before writing and gives a visible writing by evaporation of the polar solvent after writing. Whereas writing is not discernible when it is drawn, this type of writing material is not suitable as ink for usual writing instruments. A dye for typewriters consisting of an organic electron donor compound (colorless dye), a compound having a phenolic hydroxyl group (developer) and a nonvolatile compound (desensitizer) is also disclosed in JP 48085/1976. ) which desensitizes the color development reaction between these two compounds. The writing drawn with such a dye is colored as soon as it is drawn. However, when the developer present in the pattern is removed by evaporation by heating or washing with a wash, the writing is rendered colorless or discolored. Such an erasing technique is not simple compared to the use of an eraser or erasing liquid. This dye is therefore not suitable as erasable ink for conventional typewriters. In addition, it does not provide a stable writing and good complexion may not fade or discolor over time as the usual ink.

The present invention aims to propose
an original method of writing and erasure which makes it possible to obtain a writing that is darker and sharper than that drawn in pencil, as well as to easily erase this writing when necessary;
an ink capable of giving a stable, complexion-free writing that is not likely to fade or fade over time, such as the usual ink-writing, and an eraser capable of easily and completely erasing the writing drawn with this ink;
- a set of a writing instrument that allows to draw in ink a clear writing, and an instrument to be erased that allows to easily and completely erase this writing when necessary.

 The Applicant has found that when written using colored ink having a phenolic hydroxyl developer and an electron donor colorless dye capable of acquiring a color under the action of said developer dissolved in a solvent which does not inhibit the color development reaction between said developer and said colorless dye, a dark, clear writing similar to that made with the usual ink can be obtained; this writing is not likely to fade or fade over time under the effect of a desensitizer because the ink contains no polar desensitizing compounds, that is to say desensitizers making the dye colorless developed ; and the traced writing of this ink can easily and completely be erased by an eraser comprising a desensitizing polar compound.

 According to one aspect of the present invention there is provided a writing and erasing method comprising writing with colored ink comprising a phenolic hydroxyl group developer, a colorless electron donating dye capable of coloring under the action of said developer and a solvent which does not inhibit the color development reaction between said developer and said colorless dye, and then the erase of the writing traced to said colored ink by means of an eraser comprising a polar desensitizer component which renders said color-donating dye colorless.

 In another aspect of the present invention, there is provided a set of an ink and an eraser for this ink. The ink is a developer colorless coloring system ink comprising a phenolic hydroxyl developer, a colorless electron donating dye capable of acquiring color under the action of said developer and a solvent which does not inhibit the developmental reaction. color between said developer and said colorless dye.

In order to obtain a stable writing and good complexion not likely to fade or discolor exposure of external agents such as heat, light, water etc .., especially after writing, it is preferable to use as developer a phenol resin of the novolac type and as solvent a monophenyl ether of aromatic alcohol and / or ethylene glycol. Said ink eraser comprises a polar desensitizer compound, that is, a desensitizer which renders the colored ink colorless. It is possible to use a liquid polar compound as a desensitizer. However, in order to oppose the reappearance of the erased writing and to be able to re-write the same ink on the surfaces that have just been erased, it is it is preferable to use as the eraser a solution of a weakly volatile desensitizing polar compound dissolved in a volatile solvent with a boiling point of not more than 160 ° C., this polar compound being solid at ordinary temperature and having a melting point of 600 ° C. or more but a vapor pressure of 1 mmHg or less at 1500C.

 In yet another aspect of the present invention there is provided a set of a writing instrument and an eraser. Said typewriter is composed of a first barrel, an ink dispenser provided in this first barrel, an ink channeling member for supplying ink to said ink tank at the tip of said first barrel and a writing spout provided at the tip of said ink channeling member. The ink is a colored ink comprising a phenolic hydroxyl developer, an electron donating colorless dye capable of acquiring color under the action of said developer, and a solvent inhibiting the color developing reaction between said developer and said developer. Colorless dye. Said erasing instrument is composed of a second barrel, a liquid reservoir to be erased provided in said second barrel, a porous channeling member for supplying a liquid to be erased from said liquid reservoir to be erased. at the tip of said second barrel, and a liquid application member to be erased formed by passing said porous channel member at the tip of the second barrel. Said liquid to be erased comprises a polar desensitizer which renders said colored ink colorless.

 Said typewriter may be in the form of a pen-type writing instrument. The ink channeling member may be formed of a felt or fibrous wick, and the writing tip may be formed by extending the wick at the tip of the first barrel.

 Alternatively, said writing instrument may be in the form of a pen-type writing instrument.

Said ink channeling member may then be formed of a bushing through which a hole passes, and the writing spout may be formed of a ball to be journalled in the sleeve, whence it extends in part.

 The barrel of the writing instrument and that of the erasing instrument can be made separately, but can also be formed of a single barrel divided into two compartments by a partition. In this case, there is provided in one compartment of the cylinder 1 the ink tank and in the other compartment of the cylinder, the liquid reservoir to be erased.

 The instrument to be erased may be a solid molded article prepared by uniformly dispersing microcapsules in a solidifying agent matrix, solidifying the dispersion and molding. Said microcapsules contain as the core material a liquid to be erased, which contains a polar desensitizing compound which renders said colored ink colorless.

The invention will be better understood from the detailed description given below with reference to the accompanying drawings, in which:
FIG. 1 is a sectional view of a felt pen type writing instrument embodiment belonging to a set of a writing instrument and an eraser according to the present invention;
Figs. 2a and 2b are cross-sectional views of another tipbill-type writing implement embodiment of a set of a writing instrument and an eraser according to the present invention;
Fig. 3 is a sectional view of another embodiment of a writing implement belonging to a set of a writing instrument and an eraser according to the present invention;
FIGS. 4 and 5 are cross-sectional views of assemblies of a writing and erasing instrument according to the present invention in which writing means and erasing means are provided at opposite ends of a barrel;
Fig. 6 is a perspective view of another eraser embodiment comprised of a solid molded article and belonging to a set of a writing instrument and an eraser according to the present invention;
FIGS. 7 and 8 are sectional views of other overall embodiments of a writing instrument and an erasing instrument according to the present invention in which the erasing instrument, composed of a solid molded article, is provided at the rear end of the writing instrument.

 The writing ink used according to the present invention can be prepared by dissolving a phenolic hydroxyl developer and an organic electron donor compound (hereinafter colorless dye), capable of acquiring color under the action of said developer in a solvent which does not inhibit the color development reaction between said developer and said colorless dye.

 The colorless coloring system / developer thus prepared contains a dye developed under the action of the developer, and is dark in color as the conventional oily ink. This gives a dark and clean writing. In addition, the writing is not likely to fade or fade over time due to a desensitizer because the ink does not contain polar compounds at all, ie desensitizers. of a nature to render the colored ink colorless.

The developer containing a phenolic hydroxyl group must have a fairly low volatility (preferably at a boiling point of 3200C or higher) so that the writing does not discolour in the long run and be soluble in a solvent suitable for the preparation of ink. Any material satisfying these conditions may be used, without particular limitation. Examples of suitable developers for the purposes of the invention include p-nonylphenol, 2,2'-methylene-bis-p-nonylphenol. 2,4-dinonylphenol, styrene hydroquinone, styrene alkylphenol, nonylated pyrocatechol, alkylphenol novolaks, o-phenylphenol, p-benzylphenol, nonylated bisphenol A, halogenated bisphenol A, halogenated alkylphenol novolaks and 2,2'-methylene-bis-p-chlorophenol
These developers may be used either alone or in admixture with one or more of the above-mentioned developers.

 Examples of colorless dyes capable of showing a color under the developer's reaction are the organic color-generating compounds of the phthalide series such as crystallized violet lactone and malachite green lactone; color-forming organic compounds of the fluorannes series such as 3-dimethylamino-6 = methoxyfluoranev 3,6-diethoxy-fluoran, 1,2-benzo-6-diethylaminofluoran, 2-anilino-3-methyl-6-pyrrolidinofluoran , 3 ', 6'-bis (diethylamino) -spiro (phthalan-1,9'xanthine), and - 1,1-bis (p-aminophenyl) phthalan and organic color-forming compounds of the spiropyran series such as di 1,3-naphtho-spiropyran, xantho-naphtho-spiropyran and benzo-s-naphthoisospiropyran.

 A colorless dye amount of about 1 to 40% by weight based on the total amount of ink is preferred from the double point of view of the concentration and the dissolving stability of the ink. A colorless to color developer / color ratio of about 1: 3 to 20: 1 is preferred from the dual point of view of the color intensity and color stability of the ink.

 The ink solvents to be used according to the present invention are those capable of dissolving the developer and the colorless dye, but not inhibiting the color developing reaction occurring therebetween. Any of these solvents can be used without any particular limitation.

As examples of suitable solvents for the purposes of the invention, mention may be made of non-polar solvents such as 2-methylpentane, hexane, carbon tetrachloride, cyclohexane, heptane, methylcyclohexane, ethylcyclohexane, toluene, xylene, dimethylbenzene, isopropylbenzene, decalin, tetralin, dodecylbenzene, cyclohexylbenzene, methylnaphthalene, dialkylarylmethanes and tetrachlorethylene.

 Such ink solvents may be used either alone or in admixture with one or more of the above-mentioned solvents. A quantity of solvent of about 5 to 50% by weight based on the total amount of ink is preferred from the dual point of view of the stability and flow characteristics of the ink.

 The Applicant has discovered from further studies that, although the developer used in the colorless dye / developer ink according to the present invention may very well be selected from the various above-listed compounds, of writing is greatly influenced by the stability of the developer present in the ink-drawn writing, and among these developers, phenol resins of the novolac type are particularly preferred because they remain stably present in writing without being evaporated or eliminated by external agents such as heat, light, water, etc. and are therefore able to give a good dyed writing that retains the same color intensity as when it was drawn.

 The Applicant has further found that when using novolac type phenolic resins as developer, the preferred solvents for the developer and the colorless dye are the aromatic alcohols and the monophenyl ether of ethylene glycol. Whereas these solvents are polar compounds, they have a desensitizing effect. They therefore seem to have to inhibit the color development reaction in the colorless / developer coloring system and therefore can not be used as solvents for ink.

However, these polar solvents are effective as solvents for the ink according to the present invention. The reason why they can be used effectively according to the present invention seems to be the following: since the novolak type phenolic resins and the colorless dye dissolve well in the aromatic alcohols and the monophenyl ether of ethylene glycol and thus the color development reaction is accelerated, this reaction takes precedence over the desensitizing effect of the polar solvents. Since the colorless dye and the developer dissolve well in such polar solvents, ink with substantially good physical properties can be obtained and insoluble bodies are not likely to precipitate in the long run.

 Examples of the aromatic alcohols are benzyl alcohol, phenylethyl alcohol, 3-phenyl-1-propanol-4-phenyl-2-butanol and methylphenylcarbinol. On the other hand, the reason why the monophenyl ether of ethylene glycol is selected from the glycols to be used is that its desensitizing effect is lower than that of the other glycols.

 In a preferred embodiment of the colorless type dye / developer ink, that is, ink having a novolac type phenolic resin as developer, the preferred amount of colorless dye is from about 10 to about 30. % by weight based on the total amount of ink, the preferred novolac / colorless phenol resin developer ratio is about 1: 3 to 10: 1, and the preferred amount of solvent such as aromatic alcohol or ether monophenyl ethylene glycol is about 25 to 50% by weight based on the total amount of ink.

 In the above embodiment of the colorless / developer coloring system having as developer the phenolic resin of the novolac type, the resistance to fading and the color fastness can be further increased during prolonged exposure to sunlight, adding to the ink and dissolving a metal salt of an aromatic carboxylic acid. As examples of metal salts of aromatic carboxylic acids, there may be mentioned those having at least one hydroxyl group on the aromatic ring. The metal salts of aromatic carboxylic acids containing said ortho hydroxyl group are particularly preferred. Examples of the aromatic carboxylic acids are salicylic acid, 5-tert-butylsalicylic acid, 3-phenylsalicylic acid and 3-methyl acid. 5-tert-butylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 3,5-diamylsalicylic acid, 3-cyclohexylsalicylic acid, 3-methyl-5-isoamyl-salicylic acid, 5-isoamylsalicylic acid, 3,5-di-sec-butylsalicylic acid, 5-nonylsalicylic acid, 2-hydroxy-3-methylbenzoic acid, m-cresotinic acid, 5,5'-acid, methylenedisalicylic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, anacardic acid, 1-hydroxy-2-naphthoic acid, 2-hydroxy-3-naphthoic acid, 2-hydroxy-1-naphtholec acid and 3-phenyl-5- (α, α-dimethylbenzyl) -salicylic acid. Examples of metals used to form metal salts aromatic carboxylic acid are zinc, aluminum, tin and nickel. Such aromatic carboxylic acid metal salts may be used either alone or in admixture with one or more of the other above-enumerated aromatic carboxylic acid metal salts. Said aromatic carboxylic acid metal salt is used in an amount ranging from 0.1 to 20% by weight, based on the total amount of ink.

 In the above embodiment of colorless / developer coloring system ink using novolac type phenolic resin developer, it is possible in some cases that the erased writing tends to recolor slightly yellow when Ink marks marks erased stay long after erasing the ink-drawn writing with the ink affect eraser. It is almost possible to avoid such a slight recolouration after erasure, then prolonged residence, by the addition to ink of a triester phosphite. Preferred triester phosphites are those of alcohols having five or more carbon atoms. Examples of these esters include trinonylphenyl phosphite, tricresyl phosphite, dinonylphenyl-2-ethylhexyl phosphite, tridodecylphenyl phosphite, di-2-ethylhexyl-phenyl-phosphite, di-2-ethyl-nonylphenyl-phosphite, di-2-ethylhexyl-phosphite, dicrésyl-octyl-phosphite, dicrésyl-nonyl phenyl-phosphite, 1-o-biphenyl-nonylphenyl- phosphite, tris-isopropylidene-phenyl-phosphite and tris-4,4g-methylene-bisphenyl-phosphite.

 Such phosphite triesters may be used either alone or in admixture with one or more of the other triester-pliosphites listed above. The triester is used in an amount of at least 0.2% by weight based on the total amount of ink. Liquid triester phosphites are well compatible with novolak type phenolic resin. The triester can thus be incorporated in the solvent.

In this case, the triester-liquid phosphite can be used up to 30% by weight based on the total amount of ink.

 Optionally, a resin that does not inhibit color development can be used to control the viscosity of the ink or the immutability properties of the writing. Examples of such resins are polybutene, styrene / butadiene copolymers, polystyrene and polyolefins a.

 Optionally, a lubricant such as paraffin wax, polyolefin wax or metallic soap may also be used to control the smoothness of the ink. In the ballpoint pen ink preparation, polyvinylpyrrolidone, polyvinyl butyral, polyvinyl ether, oleic acid and oleates can be added to the ink in order to adjust the viscosity thereof.

 Briefly, the ink used according to the present invention can be easily prepared by mixing the developer, the colorless dye and the ink solvent in an apparatus generally used in the manufacture of ink, such as a kneader, an ink mill. three-roll or heated stirrer.

 When it is desired to add a resin and a lubricant, these components can be added to those mentioned above and mixed in an analogous manner.

 The writing drawn in the above ink is easy to erase with a polar desensitizer compound such as alcohol, ketone, ether, amine or amide. It is believed that the colored complex formed by reaction between the developer and the colorless electron donating dye is decomposed by the desensitizing action of the polar compound, resulting in rendering the writing colorless. When a readily vaporizable polar compound is used as the eraser, it is possible that once the eraser is completely vaporized from the erased surface, the previously rendered colorless electron donor dye reacts with the developer again, reappearing. On the other hand, when the polar compound serving as an eraser is difficult to vaporize and remains stable over time, this compound has an erasing power which remains stable long after the erasure and the erased writing does not reappear. more.

However, when attempting to write the same ink on the erased surface, soon after erasure, there is a risk that the freshly drawn writing will be rendered colorless by the eraser remaining on the erased surface. Consequently, in order to erase the writing so as to be able to rewrite the same ink as soon as after erasing, it is necessary to use polar compounds which are solid at ordinary temperature, so that in fusion they exert a desensitizing effect and can erase the ink, but after evaporation of the solvent, they solidify and no longer exert the desensitizing effect. Even when using such polar solvents, low volatility compounds are preferred in order to impart stable erasability. As polar compounds meeting the above requirement, desensitizing compounds having a melting point are preferred. of 600C or more, but a vapor pressure of 1mm H or less, or a boiling point of 3200C or more. Examples of such compounds include diphenyl phthalate, diphenylurethane, pentaerythritol tetraacetate, pentaerythritol tetrabenzoate, diphenylglycolic acid, ethylene glycol dibenzoate, N-phenyl-s-naphthylamine, phenyl N-phenylanthranilate, methyl N-phenylanthranilate, benzoguanamine, 4,4'-methylenebis (acetanilide), 4,4'-sulfonyl-bis (acetanilide), p-aminoacetanilide, benzacetin, 4- butoxy-N-hydroxy-benzeneacetamide, 2,3-dihydro-2,2-dimethyl-7-benzofuranol methylcarbamate, cotton wool, diaminodiphenylmethane, dianisidine, 4- (phenylmethyl phenol) carbamate, galactitol, diphenyl phthalate, 4'- (methylsulfamoyl) sulfanilylanilide, 4,4'-tetramethyldiaminodiphenymethane, polyvinylpyrrolidone, polyvinyl acetate, N-vinylpyrrolidone / vinyl acetate copolymer, ketone resins, oligo-N methylmorpholinium propylene oxide, the polyac rylates, polymethacrylates, polyesters, urea / formaldehyde resins, ethyleneurea / formaldehyde resins, ethylene-urea / butyraldehyde resins, poly-N-butoxymethylacrylamide and vinylacetate / maleic acid copolymers.

 As solvents for the dissolution of the above desensitizer components, volatile solvents boiling at 160 C or less are preferred. As examples of such solvents, mention may be made of methanol, ethanol, propanol, butanol, tetrahydrofuran, diisopropyl ether, acetone, methyl isobutyl ketone, ethyl acetate and acetate. butyl, toluene, xylene, 1,1,1-trichloroethane, trichlorethylene, perchloroethylamine, methyl ethyl ketone, methylcellosolve, ethylcellosolve, dimethylformamide, 2-nitropropane and dioxane.Among these solvents Alcohols, esters, ethers, ketones or mixtures thereof are particularly preferred since they possess a high degree of write-off power, which facilitates the appearance between the ink and the desensitizer of a regular reaction. causing a rapid erasure.

 In the preparation of a solvent-dissolving eraser in the above solvent of a solid desensitizing organic compound at ordinary temperatures, it is preferable to dissolve the desensitizing organic compound in said solvent in the desired ratio to obtain a concentration of 2 to 40% in weight.

 In order to improve the fixing power and migration characteristics of the eraser, a resin which does not oppose rewriting can be added to the eraser solution. Examples of such resins are petroleum resins, polystyrene or styrene / butadiene copolymers.

 To erase with such an eraser solution from the colorless / developer-type ink-scribed ink, the eraser solution can be applied to the writing with a brush, etc. Alternatively, a felt-type typewriter container, such as a pen with a felt wick, is used which is filled with the eraser solution to be used.

 In a method which simplifies the use, the microcapsule-based eraser solution is added, the resulting microcapsules are combined with a solidifying agent, and the resultant solid is used as a gum. The microcapsules of the eraser solution can be operated by any of the common methods such as coacervation, in situ polymerization and drying within the liquid. When the capsules have a particle size of 100 to 1000 p and a membrane thickness of 3 to 40, they are easy to break by light friction, which allows to effectively apply the eraser solution and give it an excellent stability at Examples of the foregoing solidifying agents for capsule combination are finely divided solidifying agents such as calcined gypsum, resin solutions and waxes such as pastels and pastel crayons. Upon solidification of the capsule, a filler such as calcium carbonate, talc or clay or additives such as lubricant, wax and oil may be added to adjust the hiding power and the solids concentration.

 When the eraser solution is used in the form of a liquid and applied to paper writing, it may be inconvenient for the eraser solution to seep into the back of the paper, thus erasing the writing on the paper. this back without erasing the one on the front.

To overcome this drawback, it is advisable to adjust the viscosity of the extinguishing solution so that it is 10 to 200 cP at 250C.

 In order to adjust the viscosity of the eraser solution, it is possible to adjust the amount of nonvolatile desensitizer to be added, a high molecular desensitizer (preferably 1000 or more) with a relatively low desensitizing effect, but exerting a thickening effect, together with a desensitizer of low molecular weight and desensitizer effect.

However, a preferred method is the addition of a high molecular weight organic compound such as hydroxypropylcellulose, polyvinylbutarayl, high molecular weight polyvinylpyrrolidone, cellulose aceto-butyrate or ethylene / vinyl acetate copolymer. Optionally, one can use a thickener such as hydrogenated castor oil, dibenzylidènesorbitol or metal soap;
When traces of erased ink marks are exposed to sunlight for a long time after writing erasure effected with the above eraser solution, particularly when it is a novolak-type phenolic resin that serves as a developer in the ink, the writing-tends to recolor slightly in yellowish brown. To avoid this phenomenon, it is desirable to add an ultraviolet light absorber to the eraser solution and dissolve it in it. Suitable ultraviolet light absorbers for this purpose are those which are themselves colorless or light-colored, which undergo substantially no color development reaction with a colorless dye mixed with the ink and which can dissolve in the solution. eraser. Any of these bodies can be used without limitation.

Examples of such ultraviolet light absorbers include 2-hydroxy-4-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-hydroxybenzylbenzophenone, 2- (2'-hydroxy 3 ', 5'-di-tert-butyl-phenyl) benzophenone, 5-chlorobenzophenone, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) 5-chlorobenzotriazole, 2- ( 2'-hydroxy-5'-methylphenyl) -benzotriazole, 4-tertbutylphenyl salicylate, p-octylphenyl salicylate, octoxyphenyl salicylate, 2,2'-thiobis (nickel 4-tertoctylphenolate, nickel p-toluenesulfonate and nickel octylbenzenesulfonate.These ultraviolet light absorbers may be used either in isolation or in admixture with one or more of the above-mentioned ultraviolet light absorbers.The ultraviolet light absorber is preferably used at a rate of , 2 to 5% by weight based on the amount of eraser solution.

 When erasing ink-drawn writing on paper using the above eraser solution, in some cases the paper may become excessively translucent or even transparent because a desensitizer volatil present in the eraser remains on the paper.

In such a case, traces of ink marks erased appear slightly blackened or emerge in white diazo reproduction, since the transparency of the paper is increased. To eliminate such a disadvantage, it is desirable to add to the eraser solution a fluorescent brightener. As fluorescent brightener may be used any material itself colorless or light-color dissolving in the eraser solution. Examples of such fluorescent brighteners include those of naphthalimide such as MIKAWHITE ACR concentrate, MIKAWHITE AT concentrated, MIKAWHITE ATN concentrate and MIKAWHITE BTN concentrate (Nippon products Kayaku KK); those of pyrazoline such as KAYCOLL C (product of Nisso Kako K.K.); those of stilbene: MIKEPHOL TB concentrate, MIKEPHOL TA and IIIKEPHOL TA concentrate (products of the Misui Toatsu Kagaku K.K.); those of coumarin such as KAYCOLL E (product of Nisso Kako K.K.) and WHITEFLUOR B (product of Sumitomo Kagaku K.K.); and those of bisoxasole such as WHITEX SNK, WHITEX SNP and SHITEX NKR (products of the Sumitomo Kagaku K.K.). The fluorescent brightener is used in a proportion of 0.001 to 2% by weight, based on the amount of eraser solution.

 When a good balance is struck between the whitening effect (which prevents traces of ink marks that have been erased from becoming black) to the effect opposing blank copying during diazo reproduction, It is better to use two or more fluorescent brighteners in combination.

 The convenient mode of use of the ink type colorless coloring system / developer and the associated eraser and the following. The ink can be used by means of common typewriters such as felt pens and ballpoint pens.

FIG. 1 represents a writing instrument 1 with a felt-type structure according to the present invention. In a barrel 2 is provided an ink tank 3. Ink is delivered through a felt or fibrous bit 4 to a writing spout 5 provided at the tip of the barrel. The writing spout is obtained by passing the wick 4 at the tip of the barrel 2. There is shown in 6 a detachable cap of the barrel 2.

 Figure 2a shows a ball-type writing instrument according to the present invention. In a barrel 12 is provided an ink tank 13. At the tip of the ink tank is provided a bushing 14a through which a hole 14 forming an ink passage. A ball 15 forming the writing nozzle journalled in the sleeve 14a of which it partially exceeds. At 16, there is a detachable cap of the barrel 12. The bottom of the cap is lined with a spongy elastomer 17, as shown in Figure 2a. The exposed surface of the elastomer layer 17 is covered with a film of synthetic resin 18. When the cap 16 is threaded onto the mouthpiece portion of the barrel, the ball of the spout is retained so as to be enclosed, through the film 18 into the elastomer layer 17 as shown in FIG. 2b. As a result, the ball or writing nozzle is retained in this manner, its exposed surface is covered by the film 18 so that the The ink can not evaporate from its exposed surface, which therefore remains always wet with ink. Thus, when removing the cap 16 and beginning to write, the plot is not initially defective due to insufficient ink supply.

 The ink-associated eraser solution can be used not only by brush painting or the like on the drawn writing, but also by filling with this solution a felt-type typewriter container, as shown in FIG. FIG. 3 shows an instrument to be erased. 21. In a barrel 22 there is provided a reservoir of erasure solution 23. This solution arrives, through a porous channeling member 24 made of felt or fibrous or porous resin, at the tip of the barrel. The erasing solution application part 25 is obtained by passing the porous channeling member at the tip of the barrel 22. A detachable cap of the barrel 22 is seen at 26.

 In the embodiments above, the writing instrument and the erasing instrument are made in the form of separate barrels. However, it is possible to incorporate both a pen writing instrument and an instrument to be erased in the same barrel, as illustrated in FIG. 4. In FIG. 4, the same barrel 32 is divided into two compartments by a partition 33. one of the compartments of the barrel 32 is provided with an ink tank 3. In the other compartment of the barrel 32 there is provided a reservoir for the solution of erasure 23.

Moreover, the structures are similar to those of the felt writing instrument according to FIG. 1 and the erasing instrument according to FIG. 3. The corresponding parts bear, in FIG. 4, the same reference numerals as on Figures 1 and 3.

 FIG. 5 represents an embodiment in which the ball writing instrument 11 according to FIG. 2a and the erasing instrument 21 according to FIG. 3 are incorporated in one and the same barrel 32.

 As mentioned above, the clearing solution according to the present invention is in microcapsules, which are held together by means of a solidifying agent and can then be used as a solid molded article such as a gum. Figure 6 shows an eraser 40 as a solid molded article. This solid eraser 40 has a structure in which microcapsules 41, containing the clearing solution as the core material, are uniformly dispersed in a solidifying agent matrix 42. This solid eraser 40 has the appearance of an eraser current and is preferably housed in a plastic case 43 provided with a detachable cap 44.

 When using the eraser in the form of a solid molded article 40, it can be fixed by means of a connector 50 at the rear end of the barrel 2 'of the felt-type typewriter 1 as shown in FIG. FIG. 7. This solid eraser 40 can also be fixed by means of the coupling 50 to the rear end of the barrel 129 of the ball-type type 11 as shown in FIG.

The other components shown in Figures 7 and 8 are the same as in Figures 1 and 2a. They are designated by the same reference numerals as in Figures 1 and 2a and will not be described again.

The present invention is illustrated by the examples and examples compared below. The proportions are
indicated in the examples and examples compared in parts
in weight.

Example 1
Ink preparation
p-octylphenol novolac resin (developer) 20 parts - p-nonylphenol (developer) 30 - crystallized violet lactone (dye
colorless) 15 - decalin (solvent) 25
The above mixture was dissolved by heating at 1000C for one hour, and filtered to remove small amounts of insoluble bodies to obtain a blue ink. This pen is filled with a ballpoint pen (type E according to Japanese Industrial Standard (NIJ) 6-6039-1980 for thin characters). A line is drawn on paper (type A writing paper according to NIJ P-3201) with the ballpoint pen above. The line is drawn with this ink as with the usual pen ink, and we obtain a blue line net.On leave the trait stay 10 days at 50 C and we see that it is good dyed and does not fade.

 This line is completely erased by rubbing it gently with paper soaked with a 30% solution of dioctyl adipate (eraser) in acetone. Even after the paper has been held at 500C for 10 days, the erased line does not reappear. The eraser thus proves to ensure a stable erasure.

Example 2
Preparation of the ink - 2,2'-methylenebis-p-chlorophenol (developer) 3 parts - 2-methyl-4-nonylphenol (developer) 5 - 2-anilino-3-methyl-6-pyrrolidinofluoran
(colorless dye) 2 parts - tetrachlorethylene (solvent) 6 - benzyl alcohol (solvent) 2
The above mixture was dissolved at 1000C for one hour and filtered to remove small amounts of insoluble bodies to give a black ink. This ink is filled with a piece of oily felt pen (MM50, product of the Pentel KK).

A line is drawn on paper (writing paper A) with the pen above, and a clean black line is obtained. We let this trait stay at 100C for 10 days, and we see that it is good complexion and does not fade.

Preparation of the eraser - diphenyl phthalate (desensitizer) 15 parts - polyester resin (desensitizer) (VYLON
200, product of Toyo Boseki KK) - toluene (solvent) .80 11
The above components are then mixed and dissolved by stirring at 500 ° C. for one hour to obtain an eraser solution. This eraser solution is filled with a piece of oily felt pen (F50, product of the Pentel KK) to obtain an instrument to be erased.

When rubbing three or four times with this instrument to erase the stroke drawn with the black ink above, this line is completely erased. One minute after the erasure, we try to rewrite with the black ink above on the erased surface and we draw a sharp black line. The traced line does not fade after 10 days. The erased line does not reappear.

Example 3
Ink preparation - Novolac type phenolic resin (TAMANOL PA,
product of Arakaw Kagaku KK)
(revealing) 30 parts - colorless fluoran dye (BK-14, product
Yamada Kagaky Kogyo KK) 20 - benzyl alcohol (solvent) 20 - ethylene glycol monophenyl ether
(solvent)
The above mixture was dissolved at 100 ° C for one hour, and filtered to remove small amounts of insoluble bodies to obtain a further black color according to the present invention.

 This pen is filled with a ballpoint pen (type E for thin characters). We draw with this pen a line on paper (writing paper A). We examine the writing as soon as it is drawn. It is then allowed to stay at 500C for 7 days, and the change it undergoes over time is also examined. The results are shown in Table 1.

Preparation of the erase - N-vinyl pyrrolidone / acetate copolymer
vinyl (desensitizer) 7.5 parts - ethanol (solvent) 89.5 - high molecular weight polyvinylpyrrolidone
(with an average molecular weight of 360,000)
(viscosity modifier) 3
The above components are dissolved with stirring to prepare an eraser solution. One piece of the oily felt pen (M-10, product of the Pentel KK) is filled with this eraser solution. We rub a little with this eraser the above-mentioned writing traced in black ink above, and we see that it is clearly erased.

Comparative example 1
Preparation of ink - bisphenol F (developer) 30 parts - colorless fluoran dye (BK-14) 20 - benzyl alcohol (solvent) 20 - ethylene glycol monophenyl ether
(solvent)
Ink is prepared in the same manner as in Example 3 except that bisphenol is used as the developer.
F instead of the novolak type phenolic resin of Example 3. We examine the writing as soon as traced and its modification over time. The results are shown in Table 1.

Comparative example 2
Ink preparation - phenolic resin - novolac type (TAMANOL PA)
(developer) 30 parts - colorless fluoran dye (BK-14) 20 "- diethylene glycol monobutyl ether
(solvent)
Ink is prepared in the same manner as in Example 3 except that diethylene glycol monobutyl ether is used as the solvent instead of benzyl alcohol and ethylene glycol monophenyl ether. of example 3. One examines the writing as soon as it is traced as well as its modification to the course at the time. The results are shown in Table 1.

Table 1

<tb><SEP> Write <SEP> soon <SEP> plotted <SEP> After <SEP> stay <SEP> of <SEP> 7
<tb><SEP> days <SEP> to <SEP> 500C
<tb> Example <SEP> 3 <SEP> line <SEP> black <SEP> net <SEP> almost <SEP> unchanged
<tb> Example <SEP> compared <SEP> 1 <SEP> trait <SEP> black <SEP> net <SEP> faded <SEP> to <SEP> 90% *
<tb><SEP> about
<tb> Example <SEP> compared <SEP> 2 <SEP> almost <SEP> colorless <SEP> trait <SEP> black
<Tb>
* Note: calculation based on measurement of the Y value (reflectance) using Hunter's color difference meter. For example, assuming that the Y value of the paper is 70%, that of the as soon as writing is 56% and the difference between the two is 14. When, after a certain time, the Y 'value of the writing is 63% and the difference between the Y values of the paper and the writing becomes 7%, it is said that there is 50% discoloration. Similarly, when the Y value of the writing becomes 70% and the difference between the Y values of the paper and the writing becomes zero, it is said that there is 100% fading.

 As can be seen from Table 1, a sharp line can be drawn with the ink of Example 3 according to the present invention as well as with an oily ink for a ballpoint pen. The drawn line does not fade during the rigorous test of residence at 500C for 7 days. This ink is therefore suitable as an ink that can give a good dyed writing. On the other hand, there is no difference, when writing, between the results of Comparative Example 1 and Example 3, but the writing of the example compared tends to fade over time. From these facts, it clearly follows that an ink comprising as developer the novolac type phenolic resin gives a stable color, that is to say a color writing more resistant than the ink comprising bisphenol A alone as developer .

The writing of Comparative Example 2 is almost colorless when writing and unreadable. This result is believed to be due to the fact that a color development reaction between the developer and the colorless dye is inhibited because the polar compound with desensitizing effect is used as the solvent. After evaporation of the solvent, the writing becomes dark and hardly discolouring over time, because the developer uses the novolac type phenolic resistance.

Example 4
Ink preparation - novolac type phenolic resin (TAMANOL)
(developer) 30 parts - colorless fluoran dye (PSD 150, product
Nisso Kako KK) 25 -phenylethyl alcohol (solvent) 43 - oleic acid (lubricant) 2
The above mixture was dissolved at 1000C for one hour and filtered to remove small amounts of isolable bodies to obtain a black ink according to the present invention.

 This ink is applied to paper (A-type writing paper) by a knife application method to prepare a sample. The degree of discoloration undergone by this sample after 5 hours 'test is determined by means of a decolorimeter and after a stay of 7 days at 500 ° C., as well as the color changes after 10 hours' immersion in water. The results are shown in Table 2.

Comparative example 3
Ink preparation - nonylphenol (developer) 30 parts - colorless fluoran dye (PSD 150) 25 - phenylethyl alcohol 43 - oleic acid (lubricant) 2
The procedure is as in Example 4, except that nonylphenol is used as the developer instead of the novolak type phenolic resin of Example 4. The degree of discoloration undergone by a test sample of 5 hours is determined by using a decolorimeter and after 7 days stay at 509C, as well as changes in -colour after 10 hours of immersion in water. The ink of Comparative Example 1 and commercially available ballpoint pen ink (a product of Corporation A) are simultaneously tested.

The results are shown in Table 2.

(TABLE 2 on the next page) TABLE 2

Degree <SEP> of <SEP> discoloration <SEP> Degree <SEP> of <SEP> discoloration <SEP> Change <SEP> of <SEP> color
<tb> after <SEP> test <SEP> of <SEP> 5 <SEP> h <SEP> after <SEP> stay <SEP> of <SEP> 7 <SEP> days <SEP> after <SEP> 10 <SEP > h <SEP> of immermeasured <SEP> to <SEP> decolorimeter <SEP> to <SEP> 50 C, <SEP><SEP> in <SEP> water
<tb> NBS * <SEP> NBS *
<tb> Example <SEP> 4 <SEP> 2.1 <SEP> 0.1 <SEP> No <SEP> of <SEP> change
<tb> Example <SEP> compara- <SEP> 40.1 <SEP> 42.1 <SEP> Strong <SEP> discoloration
<tb> tif <SEP> 1
<tb> Example <SEP> Compared with <SEP> 60.3 <SEP> 58.5 <SEP> Strong <SEP> Discoloration
<tb> tif <SEP> 2
<tb> Ink <SEP> oily <SEP> 3,2 <SEP> 0,09 <SEP> Contours <SEP> a <SEP> few
<tb><SEP> Trade <SEP> for <SEP> Scrambled
<tb> pen <SEP> to <SEP> ball
<tb> *) NBS = National Bureau of Standards (?)
As shown in Table 2, the degree of discolouration experienced by the ink of Example 4 according to the present invention is comparable to that of commercially available pen ink for ballpoint pen. after 10 hours of immersion in water, the color of the ink of Example 4 resists better than that of the commercially available pen-in-ball ink. The inks of Comparative Examples 1 and 3, in which only bisphenol F or p-nonylphenol alone is used as developer, are susceptible to discoloration and do not provide a good dyed writing.

 The writings plotted with the inks prepared according to Example 4 and Comparative Examples 1 to 3 were subjected to a limited number of rubs with the erasure prepared in Example 3. Each of these writings is suitable for erasure.

Example -5
Preparation of ink - p-nonylphenol (developer) 3 parts - crystallized violet lactone (colorless dye) 1,5 - cyclohexylbenzene (solvent) 2,5 - novolak type phenolic resin
(HITANOL &num; 1501, product of Hatchi Kasei
KK) (developer and visco modifier
sity) 2 "
The above components were mixed together and stirred at 1000C for 30 minutes to prepare a blue ink.

This pen has been filled with a ball pen (type NIJ S 6039-1980 E for medium characters) to make a writing instrument whose writing is erasable by the eraser according to the present invention.

Effector preparation - 4,4'-methylenebis (acetanilide) (melting point)
2360C) (desensitizer) 2 g - methonol (solvent) 4 g - ethane (solvent) 4 g
The above components were mixed together and stirred at 500C for one hour to prepare an eraser solution according to the present invention. This eraser solution was filled with an oily felt pen (MM50) to make an instrument to be erased. This instrument has been rubbed gently a limited number of times with the writing with the ballpoint pen above. The writing is completely erased. 20 seconds after the erasure, an attempt was made to rewrite the erased surface with the same ballpoint pen and a clean writing was obtained which did not disappear over time.

 For comparison, an eraser solution was prepared as above except that triethanolamine was substituted for 4,4'-methylenebis (acetanilide). The writing with the ballpoint pen above is gently rubbed a few times with this solution to be erased. The writing is completely erased. However, when attempting to rewrite with the same ballpoint pen on the erased surface one minute, five minutes, one hour and one day after erasure, the writing is instantly erased in each case.

Example 6
Preparation of eraser - polyvinyl acetate (GOSENYL E50Z2, product of the
Nippon Gosei KK) (desensitizer) 3 g - ketone resin (HILAC 110H, product of the
Hitachi Kasei KK) (desensitizer) 1 g - ethyl acetate (solvent) 5 g - methanol (solvent) 5 g
The above components are mixed together and dissolved by heating to prepare an eraser solution according to the present invention. This solution is filled with a piece of oily felt pen (MM50) to erase an instrument to be erased. The writing with the ballpoint pen obtained in Example 5 is rubbed gently a limited number of times with this instrument to be erased. The writing completely fades. 30 seconds after erasing, we try to rewrite the erased surface with the same ballpoint pen. The sharp writing obtained does not disappear over time.

Example 7
Eraser preparation - ketone resin (HILAC 111, softening point
100 C, product of Hitachi Kasei KK)
(desensitizer) 5 g - toluene (solvent) 25 g
The above components are mixed together and dissolved by heating to prepare an eraser solution according to the present invention. 9 g of this emulsion eraser solution are placed in 30 g of a 10% aqueous solution of gelatin and 30 g of a 10% aqueous solution of gum arabic are added. The mixture is stirred at high speed to emulsify. 140 ml of warm water are then added at 400 ° C. and the mixture is stirred at medium speed. 10% acetic acid is added thereto dropwise to adjust the pH to 4.1. This dispersion is maintained at -400C for two hours and then slowly brought down to 50C. 0.5 ml of glutaraldehyde is then added thereto, then the mixture is allowed to stand overnight, decanted, washed with warm water and air-dried to obtain 10.5 g of microcapsules having a particle size distribution. from 10 to 50 p and containing said eraser solution as a core material.

 The microcapsules are solidified in the following manner.

- Microcapsules 10.5 parts - Paraffin wax (54 C) 2.0 - Distearyl ketone 6.0 - Microcrystalline wax 1.0 - Hardened oil 1.5 - Talcum 3.0
The above components are mixed together. The mixture is melted by heating, gently stirred, poured into a pencil mold and cooled to solidify. The shaped article is then demolded to obtain an eraser in solid form. This eraser is rubbed 7 or 8 times with the writing made with the ballpoint pen obtained in Example 5 and it can be seen that the writing completely fades. 30 seconds after erasing, we try to rewrite the erased surface with the same ballpoint pen and we obtain a clean writing. This writing does not disappear over time. In addition, the previously erased writing does not reappear.

Example 8
The procedure is repeated as in Example 7 except that, when the eraser solution of Example 7 is placed in microcapsules, the emulsification is carried out with gentle stirring. 10.5 g of microcapsules having a particle size of 150 to 300 μm and a membrane thickness of 10 to 15 μm and containing the eraser solution as a core material are obtained.

 A solid eraser is then prepared from the above microcapsules, as in Example 7.

It is rubbed 3 to 4 times with this eraser of the writing drawn with the ballpoint pen obtained in Example 5 and it is found that it completely fades. An attempt is made to rewrite with the same ballpoint pen on the erased surface 30 seconds after erasing. The net writing obtained does not disappear over time. In addition, the writing that has been erased does not reappear.

Example 9
Eraser Preparation - N-vinylpyrrolidone Copolymer / Acetate
vinyl (3: 7) (desensitizer) 7,5 parts - ethanol (solvent) 87,5 - polyvinylpyrrolidone with high molecular weight
(average molecular weight = 360,000)
(viscosity modifier) 0 to 8
The above components are mixed together and stirred at 500 ° C. for one hour to prepare ink erasers having different viscosities. A piece of oily felt pen is filled with each of the above ink erasers to obtain eraser instruments. The erasure efficiency is tried as follows. We rub a limited number of times with the eraser the writing drawn with the ballpoint pen (still blue) obtained in Example 5. We try to write with the same ballpoint pen on both sides of a block -Notes of the trade (using watermarked ministerial paper). It is determined the possibility of writing erasure on the back side after erasure of writing drawn on the front side. The results are shown in Table 3.

Table 3

<tb> quantity <SEP> of <SEP> poly- <SEP> Viscosity <SEP> Efficiency <SEP> Possibility
<tb> inyl-pyrrolidone <SEP> of <SEP> ** <SEP> erase <SEP> of erasure
<tb><SEP> up <SEP> weight <SEP> mol- <SEP> the eraser <SEP><SEP> on <SEP> the
<tb> ulaire <SEP> (parts) <SEP> (cp) <SEP> verso
<tb><SEP> 0 <SEP> 8.5 <SEP> excellent <SEP> yes
<tb><SEP> 0.5 <SEP> 10 <SEP> excellent <SEP> almost <SEP> zero <SEP> *
<tb><SEP> 2 <SEP> 22 <SEP> excellent <SEP> zero
<tb><SEP> 3 <SEP> 38 <SEP> excellent
<tb><SEP> 5 <SEP> 80 <SEP> excellent
<tb><SEP> 7.5 <SEP> 200 <SEP> good
<tb><SEP> 8 <SEP> 235 <SEP> not <SEP> good
<Tb>
Note: * The writing is slightly scrambled.

* The viscosity is measured using a viscometer
EL (produced by Tokyo Keiki KK) with
a rotor speed of 10 tram / 250c.

 From the above results, it can be seen that if the viscosity of the eraser is between 10 and 200 cP, the writing drawn on the front can be effectively erased by avoiding the erasing of the one on the back side.

 Traces of erased ink marks do not reappear, even after a week. An attempt is made to rewrite the erased surface, with the same ballpoint pen containing blue ink, 90 seconds after erasure. A clean writing is obtained. The rewritten part does not fade even after a week.

Example 10
Eraser Preparation - N-Vinylpyrrolidone / Vinyl Acetate Copolymer
(3: 7) (desensitizer) 15 parts - ethanol (solvent) 85
The above components are mixed together and stirred at 50 ° C for one hour to prepare an ink eraser, Whereas the amount of desensitizer present in this solution is greater than that provided in Example 9, the solution has a viscosity of 22cP at 250C without any addition of viscosity modifier.

 One rubs gently on the writing drawn recto-verso on a notepad with the ballpoint pen (in blue ink) obtained in example 5, a manicure brush coated with a slight amount of the eraser below. above. The writing completely fades. An attempt is made to rewrite with the same blue ink ballpoint, 2 minutes after the erasure. A clean writing is obtained. The writing on the back of the notebook is slightly blurred in some places, but not cleared.

Example ll
Preparation of eraser - diphenyl phthalate (desensitizer) 20 parts - saturated polyester resin
(VYLON-200, product of the Toyo Boseki
KK)
(desensitizer at high weight 10
molecular) - toluene (solvent) 70
The above components were mixed together and stirred at 700C for one hour to prepare an ink eraser having a viscosity of 35.4cP at 250C. A piece of oily felt pen (M-10) is filled with this eraser to obtain an instrument to be erased. This eraser is rubbed a limited number of times of the double-sided writing on a notebook with the blue ink ballpoint pen obtained in Example 5. The writing completely fades. We try to rewrite on the erased tracks with the same blue ink ball pen a minute after erasure. We get a clean writing. The writing on the back of the notebook is slightly blurred in some places, but not cleared.

Example 12
Ink preparation - novolak resin p-cresol (developer) 30 parts - 4,4'-methylenebisphenol (developer) 10 - 2-anilino-3-methyl-6-pyridinofluoran
(colorless dye) 10 - benzyl alcohol (solvent) 30 - methylnaphthalene (solvent) 10
The above components are mixed together. The mixture was dissolved at 1000C for one hour and filtered to remove small amounts of insoluble bodies to obtain black ink. This pen is filled with a ballpoint pen (type E for thin characters). A line is drawn on paper (writing paper A) with this ballpoint pen. The line is unmistakable with this ink as with the classic ballpoint pen ink. We obtain a black line net.On let stay three months the drawn line and it is found that it holds without fading.

Eraser Preparation - Ethyleneurea-Formaldehyde Resin
(desensitizer) 10 parts - isobutyl acetate (solvent) 85 - cellulose aceto-butyrate (modifier
viscosity) 5
The above components were mixed together and stirred at 700 ° C for one hour to prepare an ink eraser having a viscosity of 57.5cP at 250C. This eraser is filled with a piece of oily felt pen (M-10) to obtain an instrument to be erased. One writes a limited number of times with this eraser from the double-sided writing on a pad-notes with the black ballpoint pen above. An attempt is made to rewrite with the same black ink ballpoint one minute after erasure. A clean writing is obtained. The writing on the back of the notebook remains unchanged.

Example 13
Ink Preparation - Phenolic Resin Novolac
(TAMANOl PA) (developer) 25 parts - crystallized violet lactone (colorless dye) 20 - benzyl alcohol (solvent) 30 - ethylene glycol monophenyl ether (zinc solvent 5 - 5-tert-butylsalicylate 5
A blue ink ball pen is prepared in the same manner as in Example 12 using the above components. You try to write on paper with this ballpoint pen using a drawing device (load: 200 g, speed: 7 cm / sec, incline: 700). The resultant write is tested in a 5-hour decolorimeter test and the degree of discoloration is determined. The results are shown in Table 4.

 Comparative example 4.

Preparation of ink - novolak type phenolic resin (TAMANOL PA) 30 parts - crystallized violet lactone 20 - benzyl alcohol 30 - ethylene glycol monophenyl ether 20
Blue ink of the above composition is prepared in the same manner as in Example 13 except that zinc 5-tertbutylsalicylate is not present in the ink composition of Example 13. The degree of fading of the writing in the same manner as in Example 13.

At the same time, the degree of discoloration undergone by writing with a commercially available blue oily ballpoint pen is determined. The results are shown in Table 4.

Example 14
Ink preparation - novolak type phenolic resin (TAMANOL PA)
(developer) 25 parts - colorless fluoran dye (BK-14) 20 - benzyl alcohol 20 - ethylene glycol monophenyl ether 30 - 3-methyl-5-tert-butylsalicylate 5
A black ink ball pen is prepared in the same manner as in Example 13 using the above components. The degree of discoloration experienced by the writing drawn with this black ink ball pen is determined in the same manner as in Example 13. The results are shown in Table 4.

Comparative Example 5
Preparation of ink - novolak type phenolic resin (TAMANOL PA) 30 parts - colorless fluoran dye (BK-14) 20 - benzyl alcohol 20 - ethylene glycol monophenyl ether 30
Black above-composition ink was prepared in the same manner as in Example 14 except that zinc 3-methyl-3-tert-butylsalicylate was not present in the ink composition of Example 14 The degree of discoloration experienced by the traced writing of this ink is determined in the same manner as in Example 14. The degree of discoloration undergone by the writing traced with a black ball point pen is determined simultaneously. trade (product-corporation B). The results are shown in Table 4.

Table 4

<tb><SEP> Degree <SEP> of <SEP> discoloration
<tb><SEP> after <SEP> 5 <SEP> h <SEP> test <SEP> at
<tb><SEP> Decolorimeter, <SEP> NBS
<tb> Example <SEP> 13 <SEP> (ink <SEP> blue) <SEP> 2,5
<tb> Example <SEP> compared <SEP> 4 <SEP> (ink <SEP> blue) <SEP> 7.0
<tb> Pen <SEP> to <SEP> ball <SEP> to <SEP> felt <SEP> oily
<tb><SEP> of <SEP> Trade <SEP> (ink <SEP> blue) <SEP> 2,3
<tb> Example <SEP> 14 <SEP> (ink <SEP> black) <SEP> 1,3
<tb> Example <SEP> compared <SEP> 5 <SEP> (ink <SEP> black) <SEP> 2,4
<tb> Pen <SEP> to <SEP> ball <SEP> to <SEP> felt <SEP> oily
<tb><SEP> of <SEP> Trade <SEP> (ink <SEP> black) <SEP> 1,2
<Tb>
It can be seen from Table 4 that the ink-discolouring resistance to ink is improved by the ink addition of a metal salt of aromatic carboxylic acid and becomes approximately comparable to that of writing. drawn with a commercially available oily felt ballpoint pen.

The writing drawn with the inks of Examples 13 and 14 and Comparative Examples 4 and 5 is erased with the ink eraser prepared in Example 3,
Example 15
Ink preparation - novolak type phenolic resin (TAMANOL PA)
(developer) 25 parts - novolak type phenolic resin (TAMANOL
510, product of Arakawa Kagaku KK)
(developer) 5 n - colorless fluoran dye (BK-14) 20 n - benzyl alcohol 20 n - monophenyl ether of ethylene glycol 20 - trinonylphenyl phosphite 10
The above components are mixed together and dissolved to prepare a black ink. A line of this ink is drawn on paper. The resulting write is left for 7 days at 50 ° C and found to remain unchanged.

Eraser Preparation - Ethyleneurea-Butyraldehyde Resin
(desensitizer) 10 parts - ethanol (solvent) 70 n - dioxane (solvent) 18.5 - polyvinylpyrrolidone with high molecular weight
(average molecular weight of 360,000)
(viscosity modifier) 1.5n
The above components are mixed together and dissolved to obtain an eraser solution. A piece of oily felt pen (M-10) is filled with this solution to prepare an instrument to be erased. We rub a limited number of times the writing traced in ink above with this instrument to be erased and it clears clearly. The erased trace is allowed to remain at 500C for a month, but it does not stain. In addition, the writing does not reappear.

Comparative example 6
Ink preparation - novolac type phenolic resin (TAMANOL PA) 25 parts - novolak type phenolic resin
(TAMANOL 510) 5 - Colorless fluoran dye (BK-14) 20 - Benzyl alcohol 20 - Ethylene glycol monophenyl ether 30
Black ink of the above composition is prepared in the same manner as in Example 15 except that the trinonyl phenyl phosphite is not present in the ink composition of Example 15. Leave the writing Drawn from this ink stay 7 days at 500C and it is found that it remains stable and without any changes.

 This writing is erased with the eraser prepared in Example 15. The erased trace is left to remain at 50 OC for one month. It can be seen that the writing recolors slightly.

Example 16
Preparation of the ink - novolac type phenolic resin (TAMANOL PA)
(developer) 30 parts colorless fluoran (PSD150) 20 - phenylethyl alcohol (solvent) 45 I '- dicrésyl 2-ethylhexyl phosphite 5
The above components are mixed together and dissolved to prepare a black ink. This pen is filled with a ballpoint pen (type E for @ thin characters). We try to write on paper with this ballpoint pen. We obtain a clear black writing. We let this writing stay 7 days at 500C and we see that it remains stable and without any change.

 This writing is erased with the instrument to be erased prepared in Example 15. The erased trace is left to stay for one month at 50 ° C. It can be seen that the erased trace does not stain.

Comparative example 7
Ink preparation - novolac type phenolic resin (TAMANOL PA)
(developer) 30 parts - colorless fluoran dye (PSD150) 20 - phenylethyl alcohol (solvent) 50
Black ink having the above composition is prepared in the same manner as in Example 16 except that dicresyl 2-ethylhexyl phosphite is not present in the composition of Example 16. From the writing drawn from this ink is allowed to stay for 7 days. at 500C is stable and free of any changes.

 This writing is erased with the instrument to be erased prepared in example 15. The erased trace is left to remain for one month at 50 ° C. It can be seen that the erased trace is colored slightly.

Example 17
Ink preparation - novolak type phenolic resin (TAMANOL PA)
(developer) 10 parts - novolak type phenolic resin
(Precondensed p-cresol / formaldehyde) 20 - Colorless fluoran dye (BK-14) 15 - Crystallized violet lactone (colorless) 2 - Benzyl alcohol (solvent) 30 - Ethylene glycol monophenyl ether (solvent) 23
The above components are mixed together and dissolved to prepare a black ink. This ink is filled with a pen (type E for thin characters) to prepare a writing instrument.

Eraser Preparation - Ethyleneurea-Butyraldehyde Resin
(desensitizer) 10 parts - ethanol (solvent) 70 - dioxane (solvent 16 - octoxyphenyl salicylate (absorber
ultraviolet light) 4
The above components are mixed together and dissolved to prepare an eraser solution. A piece of oily felt pen (M-10) is filled with this solution to prepare an instrument to be erased. The traced writing of the above ink is rubbed a limited number of times with this instrument to be erased and it is clearly erased. The erased pattern is subjected to a light fastness test for 10 hours using a decolorimeter. It can be seen that the erased writing does not reappear.

Comparative example 8
Eraser preparation - 10 parts ethylene-butyraldehyde resin - 70 "ethanol - dioxane
An eraser solution having the above composition was prepared in the same manner as in Example 17 except that the ultraviolet light absorber was not included in the eraser composition of Example 17. An instrument was prepared to erase the felt type.

 It rubs with this instrument to erase the writing drawn in black ink prepared in Example 17, and it clears clearly. The erased plot is subjected to a light fastness test in the same manner as in Example 17. It is found that the writing reappears with a pale yellow color.

Example 18
Eraser Preparation - N-vinylpyrrolidone Copolymer / Acetate
vinyl (3: 7) (desensitizer) 10 parts - ethanol (solvent) 80 - methyl isobutyl ketone (solvent) 8 - 2- (2'-hydroxy-5'-methylphenyl) benzotriazole
(ultraviolet light absorber) -2
The above components are mixed together and dissolved to prepare an eraser solution. This eraser solution is filled with an oily felt pen (M-10) to prepare an instrument to be erased. It rubs with this instrument to erase the writing drawn in black ink prepared in Example 17. The writing clears clearly. The erased plot is subjected to a light fastness test in the same manner as in Example 17. It can be seen that the erased writing does not reappear.

Comparative example 9
Eraser Preparation - N-Vinylpyrrolidone Copolymer / Acetate
vinyl (3: 7) 10 parts - ethanol 80 n - methylisobutylketone 10
An eraser solution having the above composition was prepared in the same manner as in Example 18 except that the ultraviolet light absorber was not included in the eraser composition of Example 18. An instrument was prepared to erase the felt type.

 This instrument is rubbed with the ink written in black ink prepared in Example 17.

Writing is clearly erased. The erased pattern is subjected to a light fastness test in the same manner as in Example 17. It is found that the erased pattern reappears with a pale yellow color.

Example 19
Ink preparation - novolak type phenolic resin (TAMANOL
r510) (developer) 25 parts - novolak type phenolic resin
(Precondensed p-cresol / formaldehyde) 10 - Crystallized Purple Lactone (Colorless Dye 20 - Phenyl Glycol (Solvent) 20 n - Benzyl Alcohol (Solvent) 25
The components below are mixed together and dissolved to prepare a blue ink. We fill with this ink. a ballpoint pen (type E for medium characters) to prepare a writing instrument.

Eraser preparation - N-vinylpyrrolidone / vinyl acetate copolymer
(3: 7) (desensitizer) 10 parts - ethanol (solvent) 80 parts - dioxane (solvent) 8 parts - polyvinylpyrrolidone with high weight
molecular weight (average molecular weight of
360,000)
(viscosity modifier) 1.5 part - fluorescent coumarin brightener
(WHITEFLUOR B, product of the
Sumitomo Kagaku KK) 0,01 part - fluorescent brightener of naphthalimide
(MIKAWHITE ACR concentrate, product
of the Nippon Kayaku KK) 0.5 part
The above components are mixed together and dissolved to prepare an eraser solution. An oily felt pen (M-10) is filled with this solution to prepare an instrument to be erased. The writing in blue ink above is rubbed a limited number of times with this instrument to be erased. Writing is clearly erased. The trace erased. is as white as paper and we do not notice it. An attempt is made to rewrite the erased surface with the same blue ink ball pen 60 seconds after erasure. A clean writing is obtained. The erased and rewritten lines are copied at nominal speeds of 4 to 7 using a diagonal copying machine (Recopy Superdry Model 455, a product of Ricoh Co., Ltd.). erased line and the rewritten line are absolutely not noticeable.

Comparative example 10
An ink eraser is prepared in the same manner as in Example 19 except that the fluorescent brightener is removed. An instrument to be erased of the felt type is prepared.

This instrument is rubbed with this instrument to erase the writing on paper with the blue ink ballpoint pen prepared in Example 19. The writing fades, but a stain of the oil spot type is slightly noticeable on the drawing. deleted.

An attempt is made to rewrite the erased pattern with the same blue ink ball pen, 60 seconds after erasure. A clean writing is obtained. The erased plot and the rewritten plot are copied at nominal speeds of 4 to 7 using the same copying machine as in Example 19. The erased and rewritten lines are not noticeable at a nominal pace ranging from 4 to 5.5, but the pattern appears whitish at a nominal rate of 6 to 7.

Example 20
Eraser Preparation - Ethyleneurea-Butyraldehyde Resin
(desensitizer) 10 parts - ethanol (solvent) 70 - dioxane (solvent) 18 - polyvinylpyrrolidone with high weight
molecular
(average molecular weight of 360,000)
(viscosity modifier) 1.5 - fluorescent coumarin brightener
(Kaycoll E, product-of the Nisso Kako Kob.) 0.05 "
The above components are mixed together and dissolved to prepare an eraser solution. A piece of oily felt pen (M-10) is filled with this solution to prepare an instrument to be erased. You rub with this instrument to erase from the writing on teliber paper (ivory), with the blue ink ball pen prepared according to Example 19. The writing completely fades. The superficial gloss of the paper remains around the erased line without any appreciable change.

Example compared
An ink eraser is prepared in the same manner as in Example 20 except that the fluorescent brightener is removed. An instrument to be erased with felt is prepared. It rubs with this instrument to erase the handwriting drawn on tellurious paper (ivory) with the blue ink ball pen prepared in Example 19. The writing completely fades, but the superficial gloss of the paper is changes around the erased line and the ivory color is slightly accentuated. Thus, the erased path is distinguished from other parts of the paper.

Claims (22)

 1. A method of writing and erasing, characterized in that it comprises the writing with a colored ink comprising a phenolic hydroxyl group developer, a colorless electron donor dye capable of causing a color to appear under the action said developer and a solvent that does not inhibit the color development reaction between said developer and said colorless dye, and erasing the traced writing of said colored ink with an eraser comprising a polar desensitizer compound which renders said colorant colorless electron donor developed.  2. Set of a writing instrument and an instrument to be erased, the writing instrument (1; 11) being composed of a first cylinder (2; 12; 2 '; 12'), a tank of ink (3; 13) an ink channel member (4; 14; 14a) for supplying ink to the ink tank at the tip of the first barrel and a writing spout (5; the tip of the ink channeling member, said ink being colored ink comprising a phenolic hydroxyl group developer, a colorless electron donating dye capable of developing a color under the action of the developer and a solvent which does not inhibit the color development reaction between the developer and the colorless dye, and the instrument to be erased (2i) being composed of a second cylinder (22), an erase solution tank (23) provided in this second portlet, a porous channeling member (24) for supplying solution to be erased from the solution tank to be erased in the interfering with the second barrel and an eraser portion (25) formed by partially extending the porous channel member at the tip of the second barrel, the eraser solution comprising a polar desensitizer compound which renders said ink colorless; colorful.  3. Set of a writing instrument and an eraser according to claim 2, characterized in that the writing instrument is a felt-type writing instrument (11), in that said channeling member ink is constituted by a felt or fibrous wick (4), and in that the writing spout (5) is formed by partially extending the wick at the tip of the first barrel (1).  4. Set of a writing instrument and an erasing instrument according to claim 2, characterized in that the writing instrument is a pen-type writing instrument (11), in that said passage ink channel is constituted by a sleeve (14a) traversed by a hole (14), and in that the spout to write is constituted by a writing ball (15) journalled in said sleeve, where it exceeds partially .  5. A set of a writing instrument and an eraser according to claim 2, characterized in that said porous channeling member (4) of the writing instrument is constituted by felt, fiber or porous resin.  6. Set of a writing instrument and an eraser according to claim 2, characterized in that said first barrel of the writing instrument and said second barrel (21) of the instrument to be erased are constituted by a single barrel (32) divided into two compartments by a partition (33), the ink tank (13) being provided in one compartment of the barrel and- the storage tank (23) being provided in the other compartment barrel.  7. The set of a writing instrument and an erasure instrument according to claim 2, characterized in that a removable cap (6; 16) is provided on the writing nozzle side of the writing instrument to cover the writing instrument. writing nozzle, and in that a removable cap (26) is provided on the side of the application part of the eraser solution of the writing instrument to cover this piece.  8. -A combination of a writing instrument and an eraser according to claim 7, characterized in that said cap (16) covering the writing spout (15) is provided with a layer of spongy elastomer ( 17) filling the bottom of the cap and a layer of synthetic resin film (18) covering the exposed face of the mother elasto layer, and in that the writing spout (15) is retained so as to be enclosed, through said film layer, in said elastomer layer when the writing tip of the writing instrument is covered by said cap.  9. Set of an instrument to write -and an instrument to be erased, the writing instrument being composed of a barrel (2), an ink tank (3) provided in said barrel, d ' a channel member (4; 14, 14a) for supplying ink to the ink tank at the tip of the barrel and a writing spout (5; 15) provided at the tip of said channel member, said ink being colored ink comprising a phenolic hydroxyl developer, a colorless electron donating dye capable of exhibiting color under the action of the developer and a solvent which does not inhibit the color development reaction between the developer and the dye; the erasing instrument being a solid shaped article (40) prepared by uniformly dispersing microcapsules (41) in a solidifying agent matrix (42) to combine them together and by shaping the resulting dispersion, the microcapsules containing in their interior, as the core material, an erase solution comprising a desensitizing polar compound which renders said color ink colorless.  10. Set of a writing instrument and an eraser according to claim 9, characterized in that said solid erase instrument (40) is provided at the end of the barrel (2 ') opposite to the writing nose (5) the writing instrument.  11. A set of ink and an eraser for this ink, characterized in that the ink is colored ink comprising a phenolic hydroxyl group developer, a colorless electron donating dye capable of displaying a color under the action of the developer and a solvent which does not inhibit the color development reaction between the developer and the colorless dye, and that the eraser comprises a desensitizing polar compound which renders the colored ink colorless.  12. Set of an ink and an eraser for this ink according to claim 11, characterized in that the developer of the ink is a phenolic resin novalaque type, and in that the solvent of the ink is a aromatic alcohol and / or monophenyl ether of ethylene glycol.  13. Set of an ink and an eraser for this ink according to claim 12, characterized in that the ink still contains a metal salt of an aromatic carboxylic acid.  14. Set of an ink and an eraser for this ink according to claim 12, characterized in that the ink still contains a triester phosphite.  15. The assembly of claim 11, characterized in that the eraser is a polar liquid desensitizing compound.  16. An assembly according to claim 11, characterized in that the eraser is a solution of a polar desensitizer compound dissolved in a solvent with a boiling point of 160 ° C or less, said polar desensitizing compound being solid at ordinary temperature and having a melting point of 600C or higher and a vapor pressure of 1 mmHg or less at 1509C.  17. The assembly of claim 16, characterized in that the viscosity of the eraser solution is adjusted between 10 and 200 cP at 250C.  18. The assembly of claim 17, characterized in that the viscosity adjustment of the eraser solution is operated by adding a high molecular organic compound exerting a thickening effect on the solution.  19. The assembly of claim 17, characterized in that the eraser solution contains two or more desensitizing compounds, at least one of which is a high molecular weight desensitizing compound exerting a thickening effect and in that the adjustment of the viscosity The solution is operated by adjusting the amount of said high molecular weight desensitizing compound.  20. The assembly of claim 16, characterized in that the eraser solution still contains a fluorescent brightener.  21. The assembly of claim 16, characterized in that the eraser solution still contains an ultraviolet light absorber.  22. An assembly according to claim 11, characterized in that the eraser is a solid shaped article, prepared by uniformly dispersing microcapsules containing, in their interior, a solution as a core material, in a matrix of solidifying agent for keeping them together and shaping the dispersion, the solution being obtained by dissolving in a solvent with a boiling point of 1600C or less, a polar desensitizing compound which is solid at ordinary temperatures and has a melting point of 600C or more and a vapor pressure of 1 mmHg or less at 1500C.