JP2001019888A - Eraser-usable water-base writing ink composition and writing utensil having the same therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eraser-usable water-base writing ink composition which satisfies both of an erasability such that a handwriting formed by writing on paper using the ink composition can be readily erased by an eraser and a writ ing maintenance property such that the handwriting cannot be eliminated by simply rubbing the paper with a finger or paper, and a writing utensil having the ink composition built therein. SOLUTION: The eraser-usable water-base writing ink composition contains tacky colored resin granules comprising a pigment and a tacky resin, wherein the granules have a tackiness at least partially on the surface thereof and the pigment has a particle distribution such that 70 wt.% or more of the particles are distributed in the range of 2-20 μm, or contains colored resin granules and tacky resin granules wherein 70 wt.% or more of the respective granules are distributed in the range of 2-20 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based ink composition for erasing erasers for writing and a writing instrument incorporating the same. More specifically, a handwriting obtained by writing on paper can be easily erased with an eraser, and the handwriting has a handwriting retention property that is not erased by a normal finger or the degree of rubbing between papers. The present invention relates to a composition and a writing instrument containing the composition.

[0002]

2. Description of the Related Art Conventionally, many proposals have been made on ink compositions which provide handwriting which can be erased by an eraser. The ink composition is mainly composed of a vehicle containing a colorant and a resin, and the vehicle can be roughly classified into two types: an oil-based ink using an organic solvent as a main solvent and a water-based ink using water as a main solvent. A typical example of the oil-based ink is a ballpoint pen writing erasable oil-based ink composition described in JP-B-2-47512, comprising a pigment, a specific organic solvent, and an elastomer resin having rubber elasticity. No. The ink composition has a high ink viscosity using a resin having a high molecular weight, and prevents the pigment from penetrating deeply into the paper together with the solvent, and erases the handwriting on the paper surface formed by the pigment with an eraser. It is an attempt. However, although it shows practical eraser erasability for a short period after writing, it has the disadvantage that the eraser erasability gradually decreases over time. Still another problem is that the handwriting is generally slow-drying because the solvent is hardly volatile, and the ink in the undried portion of the handwriting becomes blank due to slight friction of the finger or hand immediately after writing. (Handwriting peripheral portion) and contaminates the paper surface remarkably, and also has the drawback of contaminating the fingers and hands touching the handwriting and even clothing. Generally, an oil-based erasable ink composition containing an organic solvent as a main solvent has the same problems as the above-mentioned conventional ball-point pen writing erasable oil-based ink composition, and still has an eraser erasability and a handwriting retention property. No good balance has been obtained.

[0003] On the other hand, many proposals have been made in recent years as aqueous eraser-erasable aqueous ink compositions for writing using water as a main solvent. As an example, JP-A-4-332776 discloses that a pigment accounts for 1 to 50%,
Disclosed is an ink composition that can be erased by an eraser having a film-forming temperature of 3 to 50%, an organic solvent of 0.5 to 50%, and water of 7 to 60% having a film forming temperature of at least 0 ° C. . Since the ink composition uses a general-purpose pigment, the pigment easily penetrates into the paper, and good erasability with an eraser cannot be obtained. Further, since it does not have a film-forming property at room temperature, the preservability of the film (handwriting) is poor. As still another example, an erasable ink composition using a water-insoluble polymer-encapsulated colorant obtained by polymerizing at least one emulsion polymerizable monomer containing a dissolved colorant under emulsion polymerization conditions is disclosed. (U.S. Pat.
61, 197). Since the ink composition prepares an encapsulated colorant encapsulated in a water-insoluble polymer under emulsion polymerization conditions, the particles of the obtained encapsulated colorant are fine particles of 1 μm or less. As a result, at the time of writing, the fine colorant penetrates into the paper and is trapped, so that the eraser has poor erasability. Further, the water-insoluble dye used in the encapsulating colorant is easily extracted into the vehicle by a water-soluble polar solvent or a surfactant in an aqueous vehicle,
There is a problem in that the extracted dye stains the paper surface and traces of handwriting remain when the eraser is erased. As yet another example, 0
An erasable ink containing a resin having a film forming temperature of 0 ° C. or less or a glass transition temperature of 0 ° C. or less, colored resin particles having a particle diameter of 1 μm to 20 μm, and water, and having an ink viscosity of 5 to 35 mPa · s is proposed. (Japanese Patent Laid-Open No. 5-2796)
No. 14). In the art, although attempts have been made to reduce the penetration into the paper by increasing the particle size of the colored resin particles so that no trace of handwriting is left after erasure, the applied resin has a particle size of Is small, so that it easily penetrates into the paper surface, so that the adhesion between the paper surface and the colored resin particles on the paper surface becomes strong, and there is a problem that the eraser erasability greatly varies depending on the paper quality.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have enthusiastically developed an ink composition which can solve the above-mentioned disadvantages of the conventional eraser erasable ink composition, that is, can simultaneously satisfy eraser erasability and handwriting retention. As a result of the examination, in the conventional ink composition, as for the particle diameter of the particles relating to the coloring element and the adhesive element, the application of fine particles having a particle diameter of about 1 μm or less for at least one element adversely affects the eraser erasability. We paid attention to the effect of Particles relating to the coloring element and the adhesive element, if the particle diameter is large, it is easy to reduce or prevent penetration into the paper, and considering the normal distribution of particles when producing the particles, 2 μm
If the particles are distributed in the range of ２０20 μm, penetration into the paper can be substantially prevented. The present inventors have considered that setting such conditions must be applied to both the colored particles and the adhesive particles. That is, even if the particle size of the colorant is 2 to 20 μm, if the particle size of the adhesive particles used at the same time is 0.1 μm to 1 μm as in a general-purpose resin dispersion, the adhesive particles will No good eraser erasability can be obtained because the colorant particles penetrate into the paper and strongly fix the colorant particles on the paper from behind. On the other hand, when the colorant particles
If it is μm, a good eraser erasability cannot be obtained because the coloring agent permeates into the paper irrespective of the particle diameter of the adhesive particles. In short, the present inventors presume that none of the conventional ink compositions satisfy satisfactory eraser erasability and abrasion resistance because fine colorants and / or adhesives penetrate inside the paper. I do. Therefore, regarding the relationship between the permeability of the particles into the paper and the particle size, if the particle size of the particles relating to the coloring element and the adhesive element is approximately 2 μm or more,
The inventors have found that permeation into the inside of paper can be reduced or prevented, and completed the present invention.

[0005]

According to the present invention, at least a part of the surface of a colored resin particle composed of a pigment and an adhesive resin has tackiness, and the particle distribution of the particle is 2 μm or less.
A writing ink eraser-erasable aqueous ink composition comprising at least 70% by weight or more of an adhesive colored resin particle in a range of 20 μm, water, and a water-soluble polar solvent is required. Further, the adhesive colored resin granules may be used in the ink composition.
To 35% by weight, the weight ratio of the pigment contained in the sticky colored resin granules is 2 to 30% by weight, and the sticky colored resin granules are prepared by a suspension polymerization method. The granular resin, the adhesive resin in the adhesive colored resin granular material prepared by the suspension polymerization method, comprises a radically polymerizable monofunctional monomer and a polyfunctional monomer, the monofunctional monomer The weight ratio of the polyfunctional monomer to the monofunctional monomer is 2 to 10 for the polyfunctional monomer, and the polymerized adhesive resin having a crosslinked structure is used. The glass transition temperature is less than 40 ° C., the adhesive colored resin particles in which the pigment is dispersed in the adhesive resin in a homogeneous state are used, and the adhesive colored resin particles are formed on the paper surface. Handwriting after drying In adhering the paper and the point, and to a requirement that such each of the adhesive colored resin granules is present in a separate state or point bonding status.

The present invention further provides a pigmented resin particle, a sticky resin particle, water, and a water-soluble polar solvent, wherein the particle distribution of the colored resin particle and the sticky resin particle. Are in the range of 2 μm to 20 μm.
A writing-eraser-erasable water-based ink composition that is contained in a weight percent or more is required. Furthermore, the colored resin granules are granules obtained by polymerizing a polymerizable composition comprising at least a pigment and a radical polymerizable monomer under suspension polymerization conditions.The colored resin granules are obtained by melting and mixing a resin and a pigment. The particles are ground by a pulverization method, the weight ratio of the pigment to the resin forming the colored resin particles is 2 to 40 with respect to the pigment 1, and the adhesive resin particles are suspended. A particulate resin prepared by a polymerization method selected from a suspension polymerization method, a dispersion polymerization method, and a seed polymerization method;
30% by weight, 0.5 to 15% by weight of adhesive resin granules
Wherein the weight ratio of the colored resin granules to the sticky resin granules is 100: 2 to 200, and the sticky resin granules are particles in the handwriting after drying formed on the paper surface. It is required that they exist in a point-adhered state between each other and between the particles and the paper surface.

[0007] Further, a marking pen is obtained by incorporating the above-mentioned eraser-erasable aqueous ink composition for writing, and a shear-thinning agent is contained in the ink composition, and
m is 25 to 160 mPa · s (value at 25 ° C. in the EMD type viscometer), and the shear thinning index is 0.1 to
A ball-point pen writing eraser erasable aqueous ink composition having a particle size of 0.7, and the particle distribution of all the particles contained in the ball-point pen writing eraser erasable water-based ink composition is 2 μm or more.
A ballpoint pen which contains 80% by weight or more in the range of 10 μm, contains an adhesive colored resin granule or a stabilizer for the adhesive resin granule, and incorporates the above-mentioned eraser-erasable aqueous ink composition for writing on a ballpoint pen. Requirements.

[0008] The present invention broadly comprises inventions which differ in two constitutions. One is that the ink composition contains an adhesive colored resin particle, and the particle distribution of the adhesive colored resin particle is 2 to 2.
This is a writing eraser-erasable aqueous ink composition containing 70% by weight or more in a range of 20 μm.

The adhesive colored resin particles will be described below. In order to reduce or prevent the penetration of the particles (pigments and / or resins) into the paper described above, particles having a particle distribution of 2 to 20 μm having both a coloring element and an adhesive element are used,
Further, the present invention was completed based on the finding that the particles exhibit good tackiness and can simultaneously satisfy good eraser erasability and light abrasion resistance (indicating the retentivity of handwriting at normal times) by exhibiting tackiness. I came to. The major features of the writing eraser-erasable aqueous ink composition are that the adhesive colored resin granules to be applied exhibit (1) very low permeability into the interior of the paper, and (2) eraser-erasability. And exhibiting tackiness that simultaneously satisfies both properties. In other words, by using the adhesive colored resin granules, it is basically unnecessary to add a resin or an adhesive for imparting adhesiveness. In addition, a coloring agent for coloring may not be basically added by using an adhesive colored resin granule. In other words, the sticky colored resin granules themselves have two functions of adhesion and coloring.

The present inventors consider the reason why satisfactory eraser erasability and light scratch resistance are simultaneously satisfied with respect to the handwriting obtained from the above-mentioned aqueous eraser-erasable aqueous ink composition for writing. That is, when the handwriting obtained by the ink composition of the present invention is observed with a microscope, not only the sticky colored resin granules are present on the paper surface but also most of the particles are connected in a point-adhesive manner between the particles. (FIG. 1), the space between particles is at least occupied by space. Therefore, when erasing with an eraser, the sticky colored resin granules show good erasability because they aggregate together in a lump, and in normal friction, the sticky colored granules existing on the paper surface Since the body has a certain adhesive bonding force at the contact point with the paper surface, it is presumed that the body has a property of not peeling up to a certain frictional force. Therefore, the handwriting is similar to the handwriting characteristics written with a pencil, can be erased with an eraser, and the written handwriting is normal friction between papers,
It can withstand slight rubbing of the rubbing operation of the hand or finger during writing. In addition, the holding property and the light scratch resistance of the handwriting in the normal state mean the same as the holding property and the scratch resistance of the handwriting obtained by a pencil having a hardness of “HB” or “H”.

[0011] The adhesiveness of the adhesive colored resin particles means that the particles can be removed by friction with an eraser,
In addition, it means the degree of exhibiting the minimum required adhesive force to light rubbing. That is, if the adhesive strength is too strong, the erasability with the eraser is reduced, or a strong frictional force with the eraser is required at the time of erasure. Conversely, if the adhesive strength is too weak, the adhesive is easily peeled off by light rubbing. Therefore, it is necessary to adjust the adhesive strength to satisfy good eraser erasability and light rub resistance.
The adhesiveness is determined by the glass transition point (T
g) is not solely determined. The factors that determine the adhesiveness generally consist of various factors, and the main factors include the properties of the resin itself, for example, crystallinity, fluidity, glass transition point, molecular weight, crosslink density, etc. Are involved in a complex way. As an example, the glass transition point is-
A styrene-butadiene rubber (SBR) latex at 58 ° C. has no tackiness at room temperature and exhibits rubbery and brittle properties. On the other hand, polybutyl acrylate having a glass transition point of -45 ° C shows strong adhesiveness at room temperature. As mentioned above,
The tackiness of the resin does not necessarily depend on the glass transition point.

The production method of the adhesive colored resin granule is not particularly limited as long as at least a part of the surface of the colored resin particles containing a pigment has an adhesive property. It can be obtained using technology. As the form of the adhesive colored resin granules, the resin forming the colored resin granules is a homogeneous polymer composition having tackiness, and the entire surface of the colored resin granules is a polymer composition having tackiness. Coated ones, and those in which a part of the surface of the colored resin granule is composed of a polymer composition having continuous or discontinuous tackiness, are mentioned. As a method for obtaining the above-mentioned adhesive colored resin granules, a suspension polymerization method, a suspension polycondensation method, a suspension addition reaction method, a seed polymerization method,
A dispersion polymerization method and a submerged drying method can be applied. In order to obtain a resin in which all of the resins forming the colored resin granules have a homogeneous polymer composition having tackiness, a suspension polymerization method and a solvent evaporation method in a liquid can be mainly applied, while the entire surface of the colored granules or In order to obtain a polymer having a tacky polymer composition in which a part of the surface is continuous or discontinuous, a suspension polymerization method, a suspension polycondensation method, a suspension addition reaction method, a seed polymerization method, a dispersion polymerization method, It is possible to appropriately combine a solvent evaporation method in a liquid, or to apply a secondary surface modification method.

[0013] As an index for imparting suitable tackiness to the sticky colored resin granules, it is preferable that the glass transition point of the obtained sticky colored resin granules is less than 40 ° C. 40 ℃
When the above adhesive resin is used, the degree of adhesiveness is weak under room temperature conditions, and the light scratch resistance cannot be satisfied.

Next, the polymerization method for producing the adhesive colored resin granules will be described in more detail. The suspension polymerization method uses a lipophilic initiator, emulsifies or disperses a water-insoluble monomer or oligomer in which a pigment is dispersed in water as fine oil droplets in the presence of a dispersant, and under suspension polymerization conditions. It refers to a method of polymerizing. Generally, the size of particles obtained by the suspension polymerization method is said to be in the range of several tens μm to several mm,
By appropriately selecting an emulsifier, a dispersion stabilizer and a viscosity modifier, it is possible to synthesize an adhesive colored resin granule having a particle distribution of 2 μm to 20 μm suitable for the present invention. The suspension polycondensation method and the suspension addition reaction method respectively disperse a polycondensable or addition-reactive monomer or a prepolymer in the presence of a solvent and disperse a pigment in the presence of a solvent according to the presence of a hydrophilic dispersant. It is a method of preparing particles polymerized by polycondensation reaction or addition reaction by emulsifying or dispersing in water as small oil droplets below, and seed polymerization method is to prepare resin particles as seeds synthesized in advance. On the other hand, it is a method in which the same or different monomer is further absorbed to further polymerize and enlarge, and in the present invention, it can be suitably applied to the production of the sticky colored resin granules by the secondary treatment. The dispersion polymerization method is a method in which polymerization is carried out in a solvent in which a monomer is dissolved but a polymer is not dissolved in the presence of a dispersion stabilizer, and particles are obtained by precipitation of a formed polymer. The present invention can be suitably applied to the production of adhesive colored resin granules imparting properties. The secondary treatment refers to a treatment for further modifying the primary particles (made of a pigment and a resin) to impart tackiness to obtained primary particles (regardless of the presence or absence of tackiness). In the liquid solvent evaporation method, a dispersion obtained by dispersing a pigment in a polymer dissolved in a solvent is suspended and emulsified in water in the presence of a hydrophilic dispersant, and the solvent is heated or reduced in pressure. This is a method of obtaining polymer particles by distilling off, and is applicable mainly to the synthesis of adhesive colored resin particles having a homogeneous polymer composition as in the case of the suspension polymerization method.
A suitable polymerization method for obtaining the adhesive colored resin granules in the present invention is a suspension polymerization method.

Next, the particle size of the adhesive colored resin particles will be described. The adhesive colored resin granules applied to the writing eraser erasable ink composition of the present invention have a particle size of 2 to 20 μm.
Should have a particle distribution containing 70% by weight, preferably 80% by weight in the range of 2 μm to 15 μm.
The above is included. The particle size of the adhesive colored resin granule and the eraser erasability are closely related, and when the ratio of particles smaller than 2 μm is large, as described above, the ratio penetrating between the fibers of the paper is significantly increased, and Erasable rubber erasability cannot be obtained. On the other hand, when the proportion of particles larger than 20 μm is large, it is easy to peel off by rubbing with hands or fingers, it is difficult to obtain satisfactory light rubbing resistance, and furthermore, ink lead-out parts of various writing instruments, for example, a fiber pen, a plastic pen, It is difficult to smoothly derive the ink from the felt tip and ball tip.
The adhesive colored resin granules obtained by each of the above-mentioned polymerization methods can be subjected to wet classification such as dry classification or centrifugal sedimentation as desired so that the particle distribution satisfies the above-mentioned particle size range. Since the tacky colored resin granules have tackiness at room temperature, classification under wet conditions such as filtration and centrifugal sedimentation is preferable in order to prevent coalescence of the granules.

The reactive monomers when the adhesive colored resin granules are prepared by radical polymerization such as suspension polymerization, seed polymerization and dispersion polymerization will be described below. As the reactive monomers, those which are substantially insoluble or hardly soluble in water can be used. Radical polymerizable monofunctional monomers include ethyl acrylate, methyl acrylate, n-propyl acrylate, i-propyl acrylate, n-
Butyl acrylate, i-butyl acrylate, t-butyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, lauryl acrylate, myristyl acrylate, cetyl acrylate , Stearyl acrylate,
Acrylic esters such as 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, benzyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n- Butyl methacrylate, i-
Butyl methacrylate, t-butyl methacrylate, amyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, lauryl methacrylate, myristyl methacrylate, cetyl methacrylate, stearyl methacrylate, 2 -Methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, benzyl methacrylate, 2-
Methacrylates such as hydroxyethyl methacrylate and glycidyl methacrylate, styrene, α
-Aromatic monomers such as methyl styrene, β-methyl styrene, vinyl toluene, t-butyl styrene, chlorostyrene, vinyl benzyl chloride, vinyl pyridine, unsaturated nitriles such as acrylonitrile, and saturated carboxylic acids such as vinyl acetate And unsaturated esters of acids. N of the above monomer is normal,
i represents iso and t represents tertiary. These monofunctional monomers can be used by selecting one type or a mixture of two or more types depending on the desired tackiness. A hydrophilic monomer such as acrylic acid or methacrylic acid can be added at a ratio of 5% by weight or less based on all the monomers, if necessary, in order to impart dispersion stability of the suspended particles.

Examples of the polyfunctional monomer include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, and neopentyl glycol. Examples thereof include diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, divinylbenzene, triethylene glycol divinyl ether, butadiene, and isoprene.

In the present invention, the polymerization may be carried out using only monofunctional monomers without using polyfunctional monomers. However, in order to increase the physical strength of the adhesive colored resin granules, difunctional monomers are used. Alternatively, it is preferable to use a polyfunctional monomer in combination. The mixing ratio of the monofunctional monomer and the polyfunctional monomer is preferably 2 to 10 per 100 monofunctional monomers. If the ratio of the polyfunctional monomer is less than 2, the physical strength of the granules becomes low, the granules are destroyed when the eraser is erased, the pigment is exposed, and the paper surface is easily contaminated. On the other hand, when the ratio of the polyfunctional monomer is more than 10, the tackiness tends to decrease, and good light scratch resistance tends to be hardly obtained. Further, the addition of the polyfunctional monomer also plays an important role in the production of the adhesive colored resin granules and the stability in the ink composition. That is, the adhesive colored resin granules of the present invention have adhesiveness at room temperature atmosphere,
In addition, coalescence and aggregation are likely to occur between the granular materials due to the relatively large particle size. By using a polyfunctional monomer in the above range in order to solve or reduce such a problem, it is possible to obtain a more stable granular material having increased physical strength. Examples of the initiator applied in the polymerization method include the following substantially water-insoluble or hardly soluble compounds. A water-soluble initiator causes an emulsion polymerization reaction, and as a result, fine particles of 1 μm or less are formed.
Benzoyl peroxide, t-butyl benzoate,
Organic peroxides such as lauroyl peroxide, m-toluyl peroxide, t-butyl peroxypivalate, cumyl peroxy neodecanoate, octanoyl peroxide, decanoyl peroxide, t-butyl peroxyisopropyl carbonate , 2,2'-
Azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobispropionitrile, 2,2'-azobisvaleronitrile, 1,1'-azobis Azo compounds such as (cyclohexane-1-carbonitrile), and other common free radical generating compounds.

Next, a method for obtaining sticky colored resin granules by a suspension polycondensation method and a suspension addition reaction method will be described. Reactive monomers, oligomers, and prepolymers are applicable to the method, and the compound is a resin selected from acrylic resins, acrylic polyols, epoxy resins, urethane resins, acrylic urethane resins, and silicone resins. After the reaction, a resin having tackiness can be applied. After dispersing the pigment in the solution containing the reactive resin and further adding a crosslinking agent as needed, the emulsion is emulsified to a desired particle size in a dispersion medium containing the dispersant, and then the reaction is performed by a temperature raising operation. Accelerated, and can obtain sticky colored resin granules.

The method for obtaining a sticky colored resin particle by the solvent-in-liquid evaporation method will be described. In the solvent-in-liquid evaporation method, a polymer having tackiness is used in advance, and the pigment is dissolved in a solution in which this is dissolved in a water-insoluble solvent. Is uniformly dispersed. Emulsifying a dispersion medium containing a hydrophilic dispersant to a desired particle size, and then evaporating and distilling off the solvent by means such as heating or depressurization to obtain a sticky colored resin granule. Can be. If necessary, a physical property of the original polymer may be modified by adding a crosslinking agent before and after emulsification.
The polymers applicable to the solvent evaporation in liquid method are not particularly limited as long as they have tackiness, and specific polymers are exemplified below. Acrylic ester resin, acrylic styrene copolymer resin, acrylic ester copolymer resin, methacrylic ester resin, methacrylic ester copolymer resin, ethylene vinyl acetate resin, ethylene acrylic copolymer resin, vinyl acetate resin, polyester resin, alkyd resin And the like. Note that a phase inversion method may be used in the emulsification step of the above-mentioned solvent-in-liquid evaporation method. As a method for adjusting the adhesiveness of the adhesive colored resin granules of the present invention,
(1) By changing the kind of monomers having potential tackiness or by mixing to obtain a tacky resin, or (2) adjusting the amount of polyfunctional monomer (crosslinkable monomer) to obtain desired tackiness. Can be obtained, and furthermore, in order to adjust the tackiness, a tackifier such as rosin, rosin derivative, coumarone-indene resin, polyterpene resin, non-reactive phenol resin, petroleum hydrocarbon resin, etc. Can also be added. Further, a plasticizer such as mineral oil, liquid polybutene, lanolin, or dibasic acid ester, a pigment, an extender, or the like may be appropriately added.

[0021]
A pigment is used as the coloring means in the adhesive colored resin granular material of the present invention. When a dye is used as a colorant, the dye is transferred from the adhesive colored resin granules to the paper, dyes the paper, and cannot be erased by rubbing with an eraser. As a method of coloring the sticky colored resin granules of the present invention, a pigment in a monomer, oligomer, prepolymer or polymer in the presence of a dispersant,
If desired, a solvent is added to disperse the pigment. Thereafter, a sticky colored resin granule containing a pigment is prepared according to each reaction mode. The pigment may be uniformly dispersed in the granular material, or may be a non-uniform pigment localized in the granular material. As the pigment, azo, anthraquinone, condensed polyazo, thioindigo, metal complex salt, phthalocyanine, perinone, perylene, dioxazine and quinacridone organic pigments, carbon black, aniline black, ultramarine, yellow Inorganic pigments such as lead, titanium oxide and iron oxide can be used. These pigments can be used alone or in combination of two or more as needed. Further, special pigments include fluorescent pigments, metal powder pigments, pearl pigments, luminous pigments, reversible thermochromic pigments, and conductive pigments. The pigments may be surface-treated by various conventionally known methods for the purpose of improving the dispersibility of the monomer or the like in a solution.

It is preferable that the pressure-sensitive adhesive colored resin particles are added in an amount of 5 to 35% by weight in the ink composition.
If it is less than 5% by weight, good color density cannot be obtained, and 35% by weight.
Exceeds the solid content ratio in the ink composition increases,
It tends to hinder smooth ink ejection. Therefore, the amount of addition can be appropriately determined within the above range according to the color density of the adhesive colored resin granular material itself or the purpose of use. The adhesive colored resin granules can be used by mixing two or more kinds of adhesive colored resin granules having different tackiness, color tone, color density and particle size distribution as required. Further, the weight ratio of the pigment contained in the adhesive colored resin granules is 2 to 3
It is preferably 0% by weight. In particular, in the case of a sticky colored resin particle in which a pigment is homogeneously dispersed, if it exceeds 30% by weight, it becomes difficult to adjust the particle, particularly the particle diameter.
On the other hand, if it is less than 2% by weight, it is difficult to obtain handwriting showing a good color density. The same conditions apply to the adjustment of the primary particles for the non-homogeneous sticky colored resin particles. or,
The ink composition of the present invention has a tacky colored resin granule having a particle size distribution similar to that of the tacky colored resin granule. It can be added as desired to the body 100 in a ratio of up to 40.

Next, the colored resin granules containing the pigment of the other invention, the adhesive resin granules, water and a water-soluble polar solvent are at least composed of the colored resin granules and the adhesive resin granules. A writing eraser erasable aqueous ink composition having a particle distribution of 70% by weight or more in the range of 2 μm to 20 μm will be described.

The colored resin granules are colored granules for giving visible handwriting, and have a particle distribution of 70% by weight or more in a range of 2 μm to 20 μm in order to prevent penetration into paper. Need that. Examples of the colored resin particles include a colored resin particle in which a pigment is uniformly dispersed in resin particles, and a colored resin particle in which the surface of the resin particles is coated with a pigment.

The resins constituting the colored resin granules include polystyrene, acrylic resin, epoxy resin, melamine resin, polyester, polyvinyl chloride, benzoguanamine resin, polyamide, urethane resin, polymethyl methacrylate, and acryl-urethane copolymer. Coalesce, phenolic resin, polyethylene, polyacrylonitrile, styrene-acrylic copolymer, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer and the like. Examples of the pigment for coloring the resin include the above-described pigments. The colored resin granules can be obtained by using a conventionally known production method such as a pulverization method, a polymerization method and a spray drying method. Specifically, as the polymerization method,
Examples include a suspension polymerization method, a suspension polycondensation method, a dispersion polymerization method, and an emulsion polymerization method, and a microencapsulation method can also be used. A pulverization method, a suspension polymerization method, a suspension polycondensation method, and a dispersion polymerization method are preferably used, and more preferably, to obtain a colored granular material having a particle diameter of 2 to 20 μm used in the present invention. The suspension polymerization method and the pulverization method are used. Emulsion polymerization is not suitable for preparing colored resin granules because most of the particle size distribution is obtained as fine particles of 1 μm or less.

The method of preparing the colored resin particles into fine particles by a pulverization method will be described. The pulverization method is to apply a force such as impact, compression, friction, and shear to a material to be pulverized using a pulverizer to form a solid. A method that leads to destruction. In the present invention, the colorant and the resin are melt-mixed using a hot roll, an extruder, or the like, and after further processing into a chip shape,
A method of pulverizing with a pulverizer is exemplified.

As the colored resin granules, commercially available products can also be used. For example, trade names: Techpolymer MBX-5 series, manufactured by Sekisui Plastics Co., Ltd., Art Pearl C-, manufactured by Negami Industry Co., Ltd.
800 and the like.

A microcapsule pigment obtained by enclosing or solid-solving a colored material obtained by dispersing a pigment in a medium as a colored resin particulate material into a shell made of a resin wall film forming material by a known microencapsulation method. It can also be used. As the wall film forming substance forming the shell, gelatin, shellac, gum arabic, rosin, rosin ester, ethyl cellulose, carboxymethyl cellulose,
Paraffin, tristearin, polyvinyl alcohol,
Polyethylene, polypropylene, acrylic resin, vinyl resin, polyisobutene, polyurethane, polybutadiene, polyester, polyamide, epoxy resin, phenol resin, silicone resin, polystyrene, melamine resin and the like can be used alone or in combination. Applicable microencapsulation methods include coacervation method, in-situ polymerization method, interfacial polymerization method, submerged hard coating method, phase separation method from aqueous solution, phase separation method from organic solvent, melt dispersion cooling method, A medium suspension coating method, a spray drying method and the like can be mentioned.

Next, the adhesive resin granules added to the ink composition in combination with the colored resin granules will be described. The pressure-sensitive adhesive resin particles have a role of bonding the colored resin particles having no adhesion or tackiness to the paper surface to the paper surface to impart light scratch resistance and erasability with an eraser. The adhesive strength of the adhesive resin particles themselves and the amount of the adhesive resin in the ink composition are determined within a satisfactory range satisfying eraser erasability and light scratch resistance. In order to prevent and reduce the penetration of the adhesive resin particles into the paper, the particle distribution needs to be contained in the range of 2 μm to 20 μm in an amount of 70% by weight or more. The method of producing the adhesive resin granule is not particularly limited as long as at least the surface layer has adhesiveness, and a conventionally known resin particle synthesis method can be used.

Specific forms of the sticky resin granules include those in which the entire resin forming the sticky resin granules is a homogeneous polymer composition having tackiness, and that the entire surface of the sticky resin granules is sticky. Coated with a polymer composition having an adhesive property, the adhesive resin granules have a multilayer structure, and at least a part of the surface has adhesiveness, and at least a part of the surface of the adhesive resin granules is continuous. Or what was comprised with the polymer composition which has adhesiveness of a discontinuous state is mentioned.

As a method for obtaining the above-mentioned adhesive resin granules, a suspension polymerization method, a suspension polycondensation method, a suspension addition reaction method, a seed polymerization method, a dispersion polymerization method, a solvent evaporation in liquid, and the like can be applied. . In order to obtain a homogeneous polymer composition in which all of the resins forming the granules have tackiness, a suspension polymerization method,
A dispersion polymerization method, a seed polymerization method, and a solvent-in-liquid evaporation method can be applied.
It is possible to appropriately combine a suspension polymerization method, a suspension polycondensation method, a suspension addition reaction method, a seed polymerization method, a dispersion polymerization method, and a solvent evaporation method in a liquid, or to apply a secondary treatment surface modification means. it can. Examples of the multilayer structure include those having a hard central portion and an adhesive surface layer portion. The secondary treatment for imparting tackiness refers to a process for imparting tackiness by further modifying the primary particles with respect to primary particles obtained regardless of the presence or absence of tackiness.

The adhesive resin particles are preferably prepared by at least one polymerization method selected from a suspension polymerization method, a dispersion polymerization method and a seed polymerization method, and more preferably by a seed polymerization method. A dispersion polymerization method can be used to obtain a granular material (a granular material having a narrow particle distribution) exhibiting a sharp (sharp angle) particle distribution curve, so that the classification treatment after the reaction can be substantially omitted.

The adhesiveness of the adhesive resin granule is as follows.
It means that it can be removed by rubbing with an eraser and shows the minimum required adhesive force against slight abrasion. That is, if the adhesive strength is too strong, the erasability with the eraser is reduced, or a strong frictional force with the eraser is required at the time of erasure. Conversely, if the adhesive strength is too weak, the adhesive resin granules are easily peeled off by light rubbing, so it is necessary to adjust the adhesive strength so as to satisfy good eraser erasability and light rub resistance. As an index for imparting suitable tackiness to the tacky resin granules, the obtained tacky resin granules preferably have a glass transition point of less than 40 ° C, more preferably less than 20 ° C. When an adhesive resin having a glass transition point exceeding 40 ° C. is used, the degree of adhesiveness is generally low under room temperature conditions, and it is difficult to accompany light scratch resistance.

The polymer used for preparing the adhesive resin granules is not particularly limited as long as it has adhesiveness. Specific examples of the polymer include an acrylate resin, an acrylic styrene copolymer resin and an acrylic resin. Examples include acid ester copolymer resins, methacrylate ester resins, methacrylate ester copolymer resins, ethylene vinyl acetate resins, ethylene acrylic copolymer resins, vinyl acetate resins, polyester resins, and alkyd resins.

When the adhesive resin particles are prepared by radical polymerization such as suspension polymerization, seed polymerization, dispersion polymerization, etc., the above-mentioned colored resin particles are used as reactive monomers and radical initiators. It can be selected from the materials to be prepared.

Next, a method for preparing a sticky resin particle by a suspension polycondensation method or a suspension addition reaction method will be described.
Reactive monomers, oligomers, and prepolymers are applicable to the method, and the compound is a resin selected from acrylic resins, acrylic polyols, epoxy resins, urethane resins, acrylic urethane resins, and silicone resins. After the reaction, a resin having tackiness can be applied. In the solution containing the reactive resin, after adding a crosslinking agent, if necessary, emulsify to a desired particle size in a dispersion medium containing a dispersant, and then promote the reaction by increasing the temperature to increase the viscosity of the adhesive resin. Granules are obtained.

Next, a method for obtaining a sticky resin particle by a solvent-in-liquid evaporation method will be described. In the solvent-in-liquid evaporation method, a tacky polymer is dissolved in a water-insoluble solvent in advance, and a hydrophilic dispersant is added. After adding the mixture to a dispersion medium containing the mixture and emulsifying the mixture to a desired particle size, the solvent is distilled off by means of increasing the temperature or reducing the pressure to obtain a sticky resin particle. If necessary, a physical property of the original polymer may be modified by adding a crosslinking agent before and after emulsification. Examples of the polymer applicable to the solvent-in-liquid evaporation method include the aforementioned polymers.

The method of adjusting the adhesiveness of the adhesive resin particles of the present invention includes (1) changing the kind of monomers having adhesiveness, mixing two or more monomers, (2)
By adjusting the amount of the polyfunctional monomer (crosslinkable monomer), a resin having a desired tackiness can be obtained. In order to further control the tackiness, rosin, a rosin derivative, a coumarone-indene resin, a polyterpene A tackifier such as a resin, a non-reactive phenol resin or a petroleum hydrocarbon resin may be added. Further, a plasticizer such as mineral oil, liquid polybutene, lanolin, or dibasic acid ester, a pigment, an extender, or the like may be appropriately added.

Next, a method of adjusting the colored resin granules and the sticky resin granules to the above-described particle distribution will be described. The colored resin granules can be adjusted to a desired particle distribution by a wet classification method or a dry classification method. As the wet classification method, a method of dispersing the granular material in a medium such as water and then classifying the particles by a centrifugal sedimentation method or a natural sedimentation method can be applied. For removing the coarse particles, a filtration treatment using a filter paper, a filter, or the like is also effective. On the other hand, in the dry classification method, a dried granular material is subjected to a variable impactor,
Cyclone, Kuracyclon, Turbo Classifier,
A classifying method using a device such as a micron separator can be applied. Classification may be repeated a plurality of times so as to obtain a desired particle size distribution. The dry classification method is also used for the classification method of copy toner for electrophotography.
Using such a classification method, a granular material having a particle distribution of 70% by weight or more in the range of 2 μm to 20 μm can be obtained using a single method or a plurality of methods. Further, in order to obtain a granular material having a more uniform particle diameter in which the amount of particles is concentrated within a narrow particle size range, a method of repeating the above classification or expanding an unnecessary particle range portion may be mentioned.

On the other hand, the dry classification is generally difficult to apply since the adhesive resin particles have adhesive properties at room temperature. Therefore, it is preferable to prepare the above-mentioned granular material so that 70% by weight or more is contained in the range of 2 μm to 20 μm in the particle preparation stage as much as possible. If classification is required, a wet classification method can be applied, and a filtration treatment using a filter paper, a filter, or the like, and a centrifugal sedimentation method are suitable. In addition, the above-mentioned method of adjusting the particle distribution of the adhesive colored resin granular material similar to that of the adhesive resin granular material can be used.

Next, the blending weight of the colored resin granules and the tacky resin granules in the ink composition and the weight ratio thereof will be described. The amount of each of the granules in the ink composition is 5 to 30% by weight for the colored resin granules, 0.5 to 15% by weight for the tacky resin granules, and It is preferable that the weight ratio of the resin particles is 2 to 200 of the adhesive resin particles with respect to the colored resin particles 100. If the amount of the colored resin particles is less than 5% by weight, good color density cannot be obtained, and if the amount exceeds 30% by weight, the solid content ratio in the ink composition becomes high, and it becomes easy to hinder smooth ink ejection. If the amount of the adhesive resin particles is less than 0.5% by weight, good light scratch resistance cannot be obtained, and if it exceeds 15% by weight, good eraser erasability may be difficult to obtain.
If the compounding ratio with the colored resin granules is less than 2, good light scratch resistance cannot be obtained, and if it exceeds 200, good eraser erasability may be difficult to obtain. Explaining the morphological features related to handwriting on a paper surface written using the writing eraser-erasable aqueous ink composition, a paper surface obtained by the ink composition containing the colored resin granules and the adhesive resin granules can be described. In the handwriting after drying formed as described above, the particulate matter contained in the ink composition is bonded in a point-to-point state between the particles and between the paper and the particles (FIG. 2). By such an action, a two-dimensional network structure having a core of the adhesive resin granules is formed continuously or discontinuously on the paper. This morphological feature simultaneously satisfies good eraser erasability and light scratch resistance.

The ink composition is prepared by uniformly mixing and dispersing the adhesive colored resin particles or the colored resin particles and the adhesive resin particles in a vehicle containing water and a water-soluble polar solvent. Can be prepared. The water-soluble polar solvent is used for the purpose of suppressing drying of the ink at the tip of writing, imparting water resistance to handwriting, and the like. As the water-soluble polar solvent, conventional general-purpose solvents that are compatible with water are all effective, and ethylene glycol, diethylene glycol,
Triethylene glycol, 1,3-propanediol,
Propylene glycol, butylene glycol, dipropylene glycol, thiodiethylene glycol, sorbitol, glycerin, polyhydric alcohols such as polyethylene glycol, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethanolamine, 2-pyrrolidone, N-methyl-2-pyrrolidone, Dimethylformamide or the like can be used alone or in combination of two or more, and the addition amount is 2 to 35 in the ink composition.
% By weight is preferred.

If desired, conventional additives such as preservatives, defoamers, antioxidants, stabilizers, pH regulators, and surfactants can also be added. As the additive, inorganic salts such as sodium carbonate, sodium phosphate, and sodium acetate, and organic basic compounds such as a water-soluble amine compound can be used as a pH adjuster. Benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, saponin and the like can be used as rust inhibitors. Examples of preservatives and fungicides include sodium phthalate, sodium salt of 1,2-benzthiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3,5,6-tetra Chloro-4- (methylsulfonyl) pyridine and the like can be used. As a humectant,
Urea, nonionic surfactants, sorbite, mannitol, sucrose, glucose, reduced starch hydrolysate, sodium pyrophosphate, and the like can be used. In addition, fluorinated surfactants and silicones as ink permeability improvers,
A nonionic, anionic or cationic surfactant, an antifoaming agent such as dimethylpolysiloxane, a dispersant, or the like may be used. The additives are so-called conventional additives, and can be used as needed from known compounds as needed. Further, a conventionally known water-soluble resin or aqueous resin emulsion can be added to the aqueous vehicle medium for the purpose of improving the fluidity of the ink, stabilizing the dispersion, and finely adjusting the adhesiveness.

Next, a writing instrument incorporating the writing eraser-erasable water-based ink composition will be described. The writing eraser-erasable water-based ink composition of the present invention is provided with a fiber chip, a felt chip, and a plastic chip attached to a writing tip, and impregnated with the ink in an ink occluding body composed of a fiber bundle housed inside a barrel, A structure that supplies ink to the writing tip, a structure in which ink is stored directly inside the barrel, and a structure in which a comb groove-shaped ink flow rate adjustment member or an ink flow rate adjustment member made of a fiber bundle is interposed, and ink is stored directly in the axis cylinder Then, there is a marking pen having a structure in which a predetermined amount of ink is supplied to the writing tip by a valve mechanism.

On the other hand, when the ink composition of the present invention is applied to a ballpoint pen, a relatively large granular material is used, so that the granular material tends to settle in the ink composition. For this reason, a shear thinning agent was added to the ink composition, and the resulting ink composition at 25 ° C.
The viscosity at 100 rpm using an MD viscometer is 25 to 16
0 mPa · s, and the shear thinning index is 0.1 to
When it is 0.7, a writing instrument that is stable over time without sedimentation or separation of the granular material can be obtained. If the ink viscosity at 100 rpm exceeds 160 mPa · s, the ink ejection property is reduced, and writing becomes impossible or fading occurs.
If the viscosity is less than 25 mPa · s, the dispersion stability of the granular material cannot be sufficiently maintained. That is, if the shear thinning index is out of the above range, the effect of the shear thinning is not proper, and the separation of the adhesive colored resin granules is prevented, and the ink ejection property and the handwriting performance are hindered. In the above, the shear thinning index of the ink is determined by an empirical formula (T = Kj ⁿ : K and n) obtained from a rheological measurement using a viscometer such as a shear stress value (T) and a shear rate value (j).
Is a calculated constant).

As the shear-thinning agent, conventionally known compounds can be used, and xanthan gum,
Welan gum, succinoglycan whose constituent monosaccharide is an organic acid-modified heteropolysaccharide of glucose and galactose (average molecular weight of about 1 to 8 million), guar gum, locust bean gum and derivatives thereof, hydroxyethyl cellulose, alkyl alginates, methacrylic acid A polymer having a molecular weight of 100,000 to 150,000 having an alkyl ester as a main component, glycomannan, a carbohydrate having a gelling ability extracted from seaweed such as agar and carrageenan, benzylidene sorbitol and benzylidene xylitol or derivatives thereof, and crosslinkability Acrylic acid polymers and the like can be exemplified, and they can be used alone or as a mixture. Further, as a shear thinning agent, polyglycerin fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyethylene glycol fatty acid esters, polyoxyethylene castor oil, polyoxyethylene lanolin, lanolin alcohol and beeswax derivatives, polyoxyethylene alkyl Ether / polyoxypropylene alkyl ethers, polyoxyethylene alkyl phenyl ethers,
Nonionic surfactants having an HLB value selected from fatty acid amides in the range of 8 to 12, neutralized dialkyl or dialkenyl sulfosuccinic acids, mixtures of N-alkyl-2-pyrrolidone and anionic surfactants, polyvinyl alcohol And a mixture of acrylic resin and the like, and can be used alone or as a mixture. The above-mentioned shear thinning agent is preferably used in the range of 0.1 to 20% by weight in the ink composition.

Next, the particle size of the granular material applied to the eraser-based water-based ink composition for writing with a ballpoint pen will be described. %, More preferably 90% by weight or more in the range of 2 μm to 10 μm. The particle distribution in the ink composition for writing with a ballpoint pen requires a greater restriction on the particle size than other writing instruments in order for the granular material to smoothly pass through a narrow gap near the ball container in the ballpoint pen tip. . 80% by weight in the range of 2μm ~ 10μm, depending on the structure of the ballpoint pen tip
It is preferable to apply the granular material contained above. More preferably, granules having a particle distribution of 90% by weight or more in the range of 2 μm to 10 μm are applied. This is because if the proportion of the particles having a size of 10 μm or more increases, coarse particles may accumulate in the vicinity of the ball receiving portion without passing through the writing portion, resulting in poor writing. Next, the adhesive colored resin granules or the stabilizing agent for the adhesive resin granules in preparing the eraser-erasable aqueous ink composition for writing with a ballpoint pen will be described. The granules tend to agglomerate or agglomerate between the sticky granules due to extreme pressure in the vicinity of the ball accommodating portion as the ball rotates during writing. For this reason, it is preferable to incorporate a sticky granular material stabilizer into the ink composition. Examples of the stabilizer include an anionic surfactant and an amphoteric surfactant, preferably an amphoteric surfactant, or a combination of an anionic surfactant and an amphoteric surfactant, And has a remarkable effect of preventing the sticky granules from agglomerating or agglomerating in the vicinity of the ball accommodating portion.

Examples of the anionic surfactant include alkyl sulfates, polyoxyethylene alkyl ether sulfates, sulfosuccinates, sulfonates, taurine derivatives, sarcosine derivatives, amide ether sulfates.
Sodium lauryl sulfate, triethanolamine lauryl sulfate, sodium myristyl sulfate, sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether sulfate, polyoxyethylene alkyl ether phosphate, fatty acid salt, alkyl ether fatty acid salt, etc. Oxyethylene lauryl ether sulfate triethanolamine salt, dioctyl sodium sulfosuccinate, sodium lauryl sulfoacetate, sodium N-lauroylmethyltaurine, N-myristoylmethyltaurine triethanolamine salt, sodium lauroyl sarcosine,
Potassium oleyl sarcosine, sodium myristoyl sarcosine, sodium polyoxy coconut fatty acid monoethanolamide sulfate, sodium lauryl phosphate, sodium polyoxyethylene cetyl ether phosphate, triethanolamine polyoxyethylene nonyl phenyl ether phosphate, triethanolamine dipolyoxyethylene lauryl ether phosphate Examples thereof include amine salts, triethanolamine salts of tripolyoxyethylene lauryl ether phosphate, triethanolamine salts of coconut oil fatty acids, and sodium polyoxyethylene lauryl ether acetate.

Examples of the amphoteric surfactant include alkyl betaine type, alkyl amino betaine type, imidazoline type, glycine type and etheramine oxide type surfactants, and lauryl dimethylamino acetate betaine,
Coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, lauric acid amidopropyl betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, laurylhydroxysulfobetaine, polyoctylpolyaminoethylglycine, lauryldimethylamine oxide, Examples thereof include polyoxyethylene coconut oil alkyldimethylamine oxide.

The structure and shape of the ball-point pen itself are not particularly limited, and conventional ball-point pens can be used. Is a ball-point pen in which a ball communicates with a chip having a tip mounted thereon and a liquid stopper for preventing backflow is in close contact with the end surface of the ink.

The ballpoint pen filled with the ink composition will be described in more detail. For the structure of the writing tip (tip), a general-purpose mechanism is more effective than before, and the vicinity of the tip of the metal pipe is placed inward from the outer surface. A chip holding a ball in a pressed and deformed ball holding portion, or a chip holding a ball in a ball holding portion formed by cutting a metal material using a drill or the like, or a metal A ball or the like held by a pipe or a chip formed by cutting a metal material and urged forward by a spring body or the like can be applied. Further, the ball having a diameter of about 0.3 to 1.2 mm, such as a cemented carbide, stainless steel, ruby, or ceramic, can be used.

For the ink containing tube for containing the ink composition, for example, a molded article made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate or the like is suitably used in terms of low ink evaporation and productivity. The ink container preferably has an inner diameter of 2.5 to 10 mm. Further, by using a transparent, colored transparent or translucent molded body as the ink storage tube, it is possible to confirm the ink color, the remaining amount of the ink, and the like. In addition to directly connecting the chip to the ink storage tube, the ink storage tube and the chip may be connected via a connecting member. In addition, the ink storage tube may be configured to house the refill in a shaft cylinder as a form of a ballpoint pen refill, or the shaft cylinder itself having a tip attached to a tip as an ink container may be inserted into the shaft cylinder. The ink may be directly filled. The inner diameter of the refill housed in the shaft cylinder is 2.5 to
The one having a diameter of 5 mm is suitably used, and the one having a diameter of 4 to 10 mm is preferably used for the inner diameter of a shaft cylinder for directly storing ink.

It is preferable to fill the back end of the ink composition contained in the ink containing tube with an ink backflow preventer. As the ink backflow preventive, any liquid or solid can be used.Examples of the liquid ink backflow preventive include non-volatile media such as polybutene and silicone oil, and if desired, silica in the medium. Aluminum silicate or the like can be added. In addition, examples of the solid ink backflow preventer include a resin molded product. Further, the liquid and solid ink backflow preventers may be used in combination.

[0054]

BEST MODE FOR CARRYING OUT THE INVENTION A writing eraser-erasable aqueous ink composition of the present invention is prepared by adding water and a water-soluble polar solvent to a medium.
Dispersion containing the adhesive colored resin granules, or, by adding the colored resin granules and the adhesive resin granules, if additives are blended, by adding the appropriate additives and stirring and dispersing It is prepared and used by filling in writing implements such as ballpoint pens, felt-tip pens and felt pens, fountain pens and brush pens.

[0055]

EXAMPLES Examples are shown below, but the present invention is not limited to these examples. In the examples, the particle size distribution was measured using a laser diffraction type particle size distribution analyzer (manufactured by Shimadzu Corporation; SALD 1100), and the glass transition temperature was measured using a differential scanning calorimeter [Rigaku Denki Co., Ltd.] Manufactured by DSC 8230L]. In addition, the compound number in an Example shows a weight part.

Example 1 Preparation of Dispersion of Adhesive Colored Resin Granules 480.0 parts of water was placed in a separable flask (2 liters), and polyvinyl alcohol [trade name: Gohsenol GL-03, manufactured by Nippon Gosei Co., Ltd.] 20.0 parts were dissolved to obtain a dispersion medium. 8.0 parts of carbon black (trade name: Printex L, manufactured by Degussa), 46.0 parts of butyl acrylate, 46.0 parts of styrene, 2,
A coloring composition comprising 2.0 parts of 2'-azobisisobutyronitrile was added, and the mixture was stirred at a high speed to form droplets of about 7 μm. Then, suspension polymerization was carried out at 60 ° C. for 6 hours while stirring was continued. After cooling to room temperature, 600.0 parts of water was added and washed to remove polyvinyl alcohol in the dispersion medium,
The sticky black granules were separated by centrifugation. 600.0 parts of water was further added to the obtained slurry of the sticky black granular material to wash it, followed by separation by centrifugation again, and adjusting the solid content to 50% by weight with water to obtain a sticky black resin granular material. A body dispersion liquid A was obtained. The glass transition temperature of the granules in the sticky black resin granule dispersion liquid A obtained as described above is 8 ° C.
And the average particle size is 8.2 μm, and the particles are 2 μm
The range of １５15 μm contained 92.5% by weight of the whole granules.

Preparation of Eraser-Writable Aqueous Ink Composition for Writing Adhesive Black Resin Granule Dispersion A 40.0 Ethylene Glycol 10.0 Penetrant 0.3 [Product Name: Acetinol EH, manufactured by Kawaken Fine Chemical Co., Ltd.] Water 49.7 Total 100.0 The above formulations were mixed and stirred with a disper until homogenous to obtain an ink composition. The viscosity of the obtained ink composition was 5.8 mPa · s (ELD viscometer, 25 ° C.).

Example 2 Preparation of Adhesive Colored Resin Granular Material Dispersion In a separable flask (2 liters), 475.0 parts of water was added, and polyvinyl alcohol [trade name: Gohsenol GL-03, manufactured by Nippon Gosei Co., Ltd.] 25.0 parts were dissolved to obtain a dispersion medium. A red organic pigment (trade name:
CINQUASIA Scarlet RT-787-
D, Ciba-Geigy) 11 parts, butyl acrylate 8
0.1 part, 3.6 parts of methyl methacrylate, 5.3 parts of ethylene glycol dimethacrylate, and 2.0 parts of t-butyl peroxypivalate are added, and a high-speed stirring is performed to form droplets of about 5 μm. After that, suspension polymerization was performed at 60 ° C. for 6 hours while stirring was continued. After cooling to room temperature, the resultant was sufficiently washed in the same manner as in Example 1, and then centrifuged. The solid content was adjusted to 50% by weight with water to obtain a sticky red resin particulate dispersion B. The glass transition temperature of the granules in the obtained sticky red resin granule dispersion liquid B is −32 ° C., the average particle size is 5.8 μm, and the particles are 2 μm to
The range of 10 μm contained 90.5% by weight of the whole granules.

Preparation of Erasable Erasable Water-Based Ink Composition for Writing Adhesive Red Granular Material Dispersion B 40.0 Ethylene Glycol 8.0 Silicone-Modified Defoamer 0.1 Preservative (trade names: Proxel XL-2, Zeneca) 0.1) Succinoglycan 0.2 (Organic acid-modified heteropolysaccharide, average molecular weight of about 1,000,000 to about 8,000,000) Phosphate ester surfactant 0.5 [Product name: Plysurf M208B, Daiichi Kogyo] Pharmaceutical Co., Ltd.] Water 51.1 Total 100.0 The above ingredients were mixed and stirred with a disper until homogeneous, to obtain an ink composition. The obtained ink composition had a viscosity (viscosity at 25 ° C. and 100 rpm by an EMD viscometer) of 44 mPa · s, and a shear thinning index (n) of 0.246.

Example 3 Preparation of Adhesive Colored Resin Granular Particle Dispersion A separable flask (2 liter) was charged with 485.0 parts of water, and methylcellulose [trade name: Metrolose 90] was added.
SH-100, manufactured by Shin-Etsu Chemical Co., Ltd.] 15.0 parts to obtain a dispersion medium. For the dispersion medium, 10.0 parts of carbon black (trade name: Printex L, manufactured by Degussa), 81.0 parts of butyl acrylate, 5.4 methyl methacrylate
Parts, 3.6 parts of ethylene glycol dimethacrylate,
A coloring composition comprising 2.0 parts of 2,2'-azobisisobutyronitrile was added, and a high-speed stirring was performed to form droplets of about 5 μm. Then, suspension polymerization was carried out at 60 ° C. for 6 hours while stirring was continued. . After cooling to room temperature, the resultant was sufficiently washed in the same manner as in Example 1, centrifuged, and the solid content was adjusted to 50% by weight with water to obtain a sticky black resin particulate dispersion C. The glass transition temperature of the granules in the obtained adhesive black resin granule dispersion liquid C is -33 ° C, and the average particle size is 5.6 µm.
And the particles are in the range of 2 μm to 10 μm.
It contained 8.5% by weight.

Preparation of Erasable Aqueous Erasable Water Ink Composition for Writing Except that 40 parts of the adhesive red granular material dispersion B used in the preparation of the ink composition of Example 2 were replaced with 40 parts of the adhesive black granular material dispersion C. An ink composition was obtained in the same manner as in Example 2. The obtained ink composition had a viscosity (viscosity at 25 ° C. and 100 rpm by an EMD viscometer) of 43 mPa · s, and a shear thinning index (n) of 0.240.

Example 4 Preparation of Adhesive Colored Resin Granular Material Dispersion A separable flask (2 liters) was charged with 485.0 parts of water, and methylcellulose [trade name: Metrolose 90] was added.
SH-100, manufactured by Shin-Etsu Chemical Co., Ltd.] 15.0 parts to obtain a dispersion medium. A blue organic pigment (trade name:
CROMOPHTAL Blue A3R, manufactured by Ciba Geigy Corporation) 12.0 parts, butyl acrylate 79.2 parts, ethyl methacrylate 7.0 parts, divinylbenzene 1.8
And 2.0 parts by weight of t-butyl peroxypivalate, and the mixture was stirred at high speed to form droplets of about 5 μm, and then suspension polymerization was carried out at 60 ° C. for 6 hours while stirring was continued. After cooling to room temperature, the plate was sufficiently washed in the same manner as in Example 1, centrifuged, and the solid content was reduced to 50% by weight with water.
To obtain a sticky blue resin particle dispersion liquid D. The glass transition temperature of the granules in the obtained adhesive blue resin granule dispersion liquid D is -32 ° C, the average particle size is 6.5 µm, and the particles are in the range of 2 µm to 10 µm.
It contained 3.5% by weight.

Preparation of Erasable Erasable Water-Based Ink Composition for Writing 40.0 parts of the adhesive red granular material dispersion B used for the preparation of the ink composition of Example 2 was applied to a non-adhesive black granular material (trade name:
Art Pearl C-800, manufactured by Negami Kogyo Co., Ltd., average particle size 6.2 μm) 5.0 parts and adhesive blue particulate dispersion D 30.0 parts, and 51.1 parts of water were further replaced with 56.1 parts of water. An ink composition was obtained in the same manner as in Example 2, except that 1 part was changed. The obtained ink composition had a viscosity (viscosity at 25 ° C. and 100 rpm by an EMD viscometer) of 44 mPa · s, and a shear thinning index (n) of 0.260.

Example 5 Preparation of Eraser-Writable Aqueous Ink Composition for Writing Erasable Adhesive Blue Resin Granule Dispersion D 40.0 Diethylene Glycol 9.0 Silicone-Modified Defoamer 0.1 Preservative (trade name: Proxel XL- 2, manufactured by Zeneca) 0.1 Hexaglyceryl monoisostearate 9.0 [trade name: S-face IS-601, manufactured by Sakamoto Pharmaceutical Co., Ltd., HLB: 10.8] Phosphate ester surfactant 0.5 [Trade name: Plysurf M208B, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] Water 41.3 Total 100.0 Among the above-mentioned blends, hexaglyceryl monoisostearate was added to a mixed solution in which water and diethylene glycol were previously mixed. Thereafter, the sticky blue resin particulate material dispersion D is added while stirring with a disper, and further, an antifoaming agent, a preservative, and a lubricant are added, and stirring is continued. Thus, an ink composition was obtained. The obtained ink composition had a viscosity (viscosity at 25 ° C. and 100 rpm using an EMD viscometer) of 43 mPa · s and a shear thinning index (n) of 0.232.

Example 6 Preparation of Sticky Resin Granules Water 60 was placed in a separable flask (2 liter) equipped with a stirrer.
0 parts, 0.2 parts of sodium lauryl sulfate and methylcellulose (trade name: Metrolose 90SH-100,
20 parts (Shin-Etsu Chemical Co., Ltd.) were dissolved to obtain a dispersion medium. 120 parts of butyl acrylate, 10 parts of methyl methacrylate, ethylene glycol dimethacrylate 2
An oil phase solution comprising 2.0 parts of 2,2'-azobisisobutyronitrile was added, and stirring was continued at 400 rpm so that the average particle diameter became about 6 µm. Then, the suspension was heated to 70 ° C. under a nitrogen atmosphere and stirred for 6 hours to carry out suspension polymerization. Thereafter, the mixture is cooled to room temperature, diluted by adding 1000 parts of water, and then subjected to solid-liquid separation by a centrifugal separation method. The solid content is adjusted to 40% with water, and the adhesive resin particulate dispersion A
I got The average particle diameter of the granular material in the adhesive resin granular material dispersion A is 7.8 μm, and the particle size is 2 μm to 20 μm.
Contained 85% by weight of the whole granules.

Preparation of Ink Composition Black resin granules 20.0 [trade name: Art Pearl C-800, manufactured by Negami Industry Co., Ltd., average particle diameter: 6.1 μm, 95.0% by weight in the range of 2 μm to 20 μm] Adhesive resin particle dispersion A 10.0 Ethylene glycol 10.0 Penetrant 0.3 [Product name: Acetinol EH, manufactured by Kawaken Fine Chemical Co., Ltd.] Silicone-modified antifoaming agent 0.1 Water 59. 6 Total 100.0 The above compositions were mixed and stirred with a disper until homogeneous, to obtain an ink composition. The viscosity of the obtained ink composition was 6.7 mPa · s (ELD viscometer, 25 ° C.).

Example 7 Preparation of Colored Resin Granules 480 parts of water was put into a separable flask (2 liter), and 20 parts of polyvinyl alcohol (trade name: Gohsenol GL-03, manufactured by Nippon Gosei Co., Ltd.) was dissolved. To obtain a dispersion medium. Carbon black (trade name: P
tintex L, manufactured by Degussa Co., Ltd.), 10 parts of methyl methacrylate, 60 parts of methyl glycol methacrylate, 30 parts of ethylene glycol dimethacrylate, and 2 parts of 2,2′-azobisisobutyronitrile. After dropping, the suspension was heated to 70 ° C. while continuing to stir,
Suspension polymerization was performed for hours. After cooling to room temperature, diluting by adding 1000 parts of water, and performing solid-liquid separation by centrifugation,
The solid content is adjusted to 50% with water to obtain a black resin particulate dispersion A.
I got The average particle diameter of the particles in the black resin particle dispersion liquid A was 5.8 μm, and the particles contained 88% by weight of all the particles in the range of 2 μm to 10 μm.

Preparation of Adhesive Resin Granules The procedure of Example 6 was repeated except that the oil phase solution of the sticky resin granules A of Example 6 was changed to 78 parts of butyl acrylate, 52 parts of ethyl methacrylate, and 1 part of t-butyl peroxypivalate. Reaction was carried out in the same procedure as in Example 6. However, the rotation speed was set to 500 rpm and the average particle diameter was adjusted to 4 μm. The solid content of the obtained adhesive resin granule was adjusted to 40% with water to obtain an adhesive resin particle dispersion B. The average particle diameter of the granular material in the adhesive resin granular material dispersion B is 4.8 μm,
The particles are in the range of 2 μm to 10 μm, 90% by weight of the whole granules
Was included.

Preparation of Ink Composition Black Resin Particle Dispersion A 40.0 Adhesive Resin Particle Dispersion B 7.0 Ethylene Glycol 10.0 Urea 5.0 Silicone-Modified Antifoam 0.1 Preservative Name: Proxel XL-2, manufactured by Zeneca) 1.0 Succinoglycan 0.2 (organic acid-modified heteropolysaccharide, average molecular weight of about 1,000,000 to 8,000,000) Phosphate ester surfactant 0.5 [Product name: Plysurf M208B, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.] Water 36.2 Total 100.0 The above-mentioned components were mixed and stirred by a disper until homogenous to obtain an ink composition. The obtained ink composition had a viscosity (viscosity at 25 ° C. and 100 rpm by an EMD viscometer) of 53 mPa · s, and a shear thinning index (n) of 0.251.

Example 8 Preparation of Colored Resin Granules 480 parts of water was placed in a beaker (2 liter), and polyvinyl alcohol [trade name: Gohsenol GL-03,
20 parts manufactured by Nippon Gosei Co., Ltd.] to obtain a dispersion medium. A phthalocyanine-based blue organic pigment (Fast Gen Blue 5007, manufactured by Dainippon Ink Co., Ltd.) is used as the dispersion medium.
5 parts, a coloring composition comprising 85 parts of an epoxy resin (bisphenol A / diglycidyl ether type, epoxy equivalent: 184 to 194) and 60 parts of ethyl acetate were added to form a droplet of about 5 μm by high-speed stirring. Temperature to 60 ° C. with an epoxy resin curing agent (aliphatic polyamine) 21
Was dissolved in 200 parts of water in about 1 hour. Then, the liquid temperature was raised to 80 ° C., and stirring was continued for 5 hours to evaporate ethyl acetate. After cooling to room temperature, washing with 1000 parts of water and solid-liquid separation by centrifugation, the solid content was adjusted with water to obtain a solid content of 50%.
To obtain a blue resin particle dispersion B. The average particle diameter of the granules in the blue resin granule dispersion liquid B is 6.7 μm,
The particles are in the range of 2 μm to 10 μm and 91% by weight of the whole granules
Was included.

Preparation of Ink Composition Blue Resin Particle Dispersion B 36.0 Adhesive Resin Particle Dispersion B 12.0 Ethylene Glycol 10.0 Silicone-Modified Defoamer 0.1 Preservative (trade name: Proxel XL) -2, manufactured by Zeneca) 0.5 Hexaglyceryl monoisostearate 9.0 [trade name: S-face IS-601, manufactured by Sakamoto Pharmaceutical Co., Ltd., HLB: 10.8] Phosphate ester surfactant 5 [Price Surf M208B, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] Water 31.9 Total 100.0 Among the above blends, hexaglyceryl monoisostearate was added to a mixture obtained by previously mixing water and ethylene glycol. After the addition, the blue resin particulate dispersion B and the sticky resin particulate dispersion B are added while stirring with a disper, and further, an antifoaming agent, a preservative, and a lubricant are added. Ete continued stirring to obtain an ink composition. The resulting ink composition has a viscosity (25 ° C.,
(Viscosity at 100 rpm by EMD viscometer) is 58 m
Pa · s, and the shear thinning index (n) was 0.271.

Example 9 Preparation of Adhesive Resin Granules 92 parts of butyl acrylate, 34 parts of methyl methacrylate, 6 parts of ethylene glycol dimethacrylate, 2,2 ' The reaction was carried out in the same manner as in Example 6, except that 2 parts of -azobisisobutyronitrile was used. However, the number of revolutions was adjusted to 600 rpm and the average particle diameter was adjusted to 3 μm. The solid content of the obtained sticky resin granules was adjusted to 40% with water to obtain a sticky resin granule dispersion liquid C. The average particle size of the granules in the adhesive resin granule dispersion liquid C was 3.2 μm, and the particles contained 85% by weight of all the granules in the range of 2 μm to 10 μm.

Preparation of Ink Composition Black Resin Particle Dispersion A 20.0 Adhesive Resin Particle Dispersion C 25.0 Glycerin 6.0 Silicone-Modified Defoamer 0.1 Preservative (trade name: Proxel XL- 2, manufactured by Zeneca) 1.0 Succinoglycan 0.26 (organic acid-modified heteropolysaccharide, average molecular weight of about 1,000,000 to 8,000,000) Phosphate-based surfactant 0.5 [Product name: Plysurf M208B, No. Tri-Ethanolamine 0.5 Water 46.64 Total 100.0 The above ingredients were mixed and stirred with a disper until uniform, to obtain an ink composition. The obtained ink composition had a viscosity (viscosity at 25 ° C. and 100 rpm by an EMD viscometer) of 49 mPa · s, and a shear thinning index (n) of 0.280.

Comparative Example 1 Preparation of aqueous ink composition Carbon black processed pigment 20.0 [trade name: Sandye Super BLACK C, manufactured by Sanyo Pigment Co., Ltd., solid content 36%, average particle diameter 0.2 μm] Acrylic emulsion 20 0.0 [trade name: Boncoat 9404, manufactured by Dainippon Ink and Chemicals, Inc., average particle diameter 0.1 μm, glass transition temperature 48 ° C.] ethylene glycol 10.0 penetrant 0.3 [trade name: acetylinol EH, Kawa Ken Fine Chemicals Co., Ltd.] Water 49.7 Total 100.0 The above ingredients were mixed and stirred with a disper until homogeneous, to obtain an ink composition. The viscosity of the obtained ink composition was 3.4 mPa · s (25 ° C., ELD viscometer).

Comparative Example 2 Preparation of aqueous ink composition Carbon black processed pigment 20.0 [trade name: Sandy Super BLACK C, manufactured by Sanyo Pigment Co., Ltd., solid content 36%, average particle diameter 0.2 μm] Acrylic emulsion 20 0.0 [trade name: Boncoat ST-372, manufactured by Dainippon Ink and Chemicals, Incorporated, average particle size 0.2 μm, glass transition temperature -11 ° C] Ethylene glycol 10.0 Penetrant 0.3 [Acetinol EH, Kawa Ken Fine Chemicals Co., Ltd.] Water 49.7 Total 100.0 The above ingredients were mixed and stirred with a disper until homogeneous, to obtain an ink composition. The viscosity of the obtained ink composition was 2.5 mPa · s (25 ° C., ELD viscometer).

Comparative Example 3 Preparation of aqueous ink composition Non-adhesive black resin particles 15.0 [Artpearl C-800, average particle size 6.2 μm, manufactured by Negami Kogyo Co., Ltd.] Styrene butadiene latex 30.0 [Product Name: Nipol 4850A, manufactured by Nippon Zeon Co., Ltd., average particle size: 0.3 μm] Ethylene glycol 10.0 Penetrant [trade name: SN Wet 366, manufactured by San Nopco Co.] 0.5 Water 44.5 Total 100. 0 The above compositions were mixed and stirred with a disper until the mixture became homogeneous to obtain an ink composition. The viscosity of the obtained ink composition was 8.2 mPa · s (25 ° C., ELD viscometer).

Comparative Example 4 Preparation of Adhesive Colored Resin Particle Dispersion The same composition as that of the adhesive red resin particle dispersion B prepared in Example 2, except that a droplet of about 1 μm was obtained by high-speed stirring. According to the method, a sticky red resin particle dispersion liquid B ′ having a solid content of 50% by weight was obtained. The glass transition temperature of the obtained granules is -32 ° C, the average particle size is 0.9 µm, and the particles contain 71.0% by weight of particles smaller than 2 µm and have a particle size of 2 µm.
The range of ２０20 μm contained 29.0% by weight of the whole granules.

Preparation of Aqueous Ink Composition An ink composition was obtained in the same manner as in Example 2, except that 40 parts of the sticky red granular material dispersion B ′ in Example 2 was replaced with 40 parts of the sticky red granular material dispersion B ′. Was. The obtained ink composition had a viscosity (viscosity at 25 ° C. and 100 rpm by an EMD viscometer) of 46 mPa · s, and a shear thinning index (n) of 0.257.

Comparative Example 5 Preparation of Adhesive Colored Resin Granular Particle Dispersion 10.0 parts of the carbon black used in Example 3 was added to C.I.
I. Solvent Black 50 (Product name: Ol
eosol Black AR, Taoka Chemical Industry Co., Ltd.
In the same manner except that 10.0 parts was used, a sticky black resin particulate dispersion liquid C 'having a solid content of 50% by weight was obtained. The glass transition temperature of the granules in the obtained adhesive black resin granule dispersion liquid C ′ is −33 ° C., the average particle size is 5.3 μm, and the particles are in the range of 2 μm to 10 μm. 9
It contained 0.5% by weight.

Preparation of Aqueous Ink Composition In the same manner as in Example 2 except that 40.0 parts of the sticky blue granular material dispersion D of Example 4 was changed to 40.0 parts of sticky black granular material dispersion C ′, An ink composition was obtained. The obtained ink composition has a viscosity (25 ° C., 100 r using an EMD type viscometer).
pm) and the shear thinning index (n) was 0.250.

Comparative Example 6 20 parts of the black resin granules of Example 6 were treated with a carbon black pigment (trade name: Sandye Super BRAC).
KC, manufactured by Sanyo Dyeing Co., Ltd., solid content 36%, average particle size 0.2 μm] An ink composition was obtained in the same manner as in Example 6 except that the composition was changed to 20 parts. The viscosity of the obtained ink composition was 7.2 mPa · s (ELD viscometer, 25 ° C.).

Comparative Example 7 Preparation of Colored Resin Granules The same composition as the colored resin granule dispersion A prepared in Example 7 was used, and the solid content was 50 wt. % Of a black resin particulate dispersion A ′. The average particle diameter of the granules in the black resin granule dispersion liquid A ′ is 2.8 μm, and the particles are 2 μm to 10 μm.
The range of μm contained 58% by weight of the whole granules.

Preparation of Adhesive Resin Granules The same composition as the sticky resin granules dispersion A prepared in Example 6 was used, and the solid content was 40% by weight by the same method except that high-speed stirring was performed to form droplets of about 2 μm. A dispersion A ′ of a sticky resin granule was obtained. The average particle diameter of the granular material in the adhesive resin granular material dispersion A ′ is 2.3 μm, and the particle size is 2 μm to 1 μm.
The range of 0 μm contained 53% by weight of the whole granules.

Preparation of Ink Composition 40.0 parts of the black resin particle dispersion A of Example 7 and 7.0 parts of the sticky resin particle dispersion B were mixed with 40.0 parts of the black resin particle dispersion A ′, An ink composition was obtained in the same manner as in Example 7, except that 7.0 parts of the dispersible resin particulate material A ′ was used. The obtained ink composition had a viscosity (viscosity at 25 ° C. and 100 rpm by an EMD viscometer) of 57 mPa · s and a shear thinning index (n) of 0.269.

Comparative Example 8 Preparation of Viscous Resin Granular Material Dispersion A similar method was used except that the composition was the same as the viscous resin granular material dispersion B prepared in Example 7 and a high-speed stirring was performed to form droplets of about 2 μm. An adhesive resin particle dispersion B ′ having a solid content of 40% by weight was obtained. The average particle size of the granular material in the adhesive resin granular material dispersion B ′ is 3.2 μm, and the particle size is 2 μm to 1 μm.
The range of 0 μm contained 61% by weight of the whole granules.

Preparation of Ink Composition The ink composition was prepared in the same manner as in Example 8 except that 12.0 parts of the adhesive resin particle dispersion B ′ of Example 8 was changed to 12.0 parts of the adhesive resin particle dispersion B ′. I got something. The obtained ink composition has a viscosity (25 ° C., 100 rpm by an EMD type viscometer).
m) was 61 mPa · s, and the shear thinning index (n) was 0.282.

Preparation of Sample Marking Pen Each of the ink compositions of Examples 1 and 6 and Comparative Examples 1 to 3 and 6 was prepared by using a fiber bundle provided at the tip end of a writing cylinder having a valve mechanism in an aluminum barrel. When writing, the chip was pressed against the paper surface during writing, the valve was opened, and a marking pen of a type that led out the ink in the shaft cylinder to the chip was used as a sample marking pen.

Preparation of Sample Ballpoint Pen The ink compositions of Examples 2 to 5, 7, 8, and 9 and Comparative Examples 4, 5, 7, and 8 were each made of stainless steel holding a cemented carbide ball having a diameter of 0.7 mm. A tip made of polypropylene is filled into a ball-point pen fitted to one end of a polypropylene barrel, and further, an ink backflow preventive (silicone grease-based) is placed in close contact with the rear end of the ink and centrifuged. Was filled in a ball-point pen of a type to be fitted to obtain a sample ball-point pen.

Erasability test and light abrasion resistance test A report paper (manufactured by KOKUYO, product no.
116AN) on a paper surface and continuously draw a circle of about 2 cm in diameter, and erase the resulting handwriting [Seed Rubber Industry Co., Ltd.
5 days after writing and one day after writing, and the degree of difficulty of erasability was determined. Regarding light scratch resistance, a filter paper (manufactured by ADVANTEC, No. 2 filter paper) was placed on the handwriting one hour after writing so that the smooth surface was on the handwriting side, and 45.5 from above.
A g / square centimeter load was applied, and the finger was slid 10 times over the handwriting to determine light scratch resistance.

Erasability and light scratch resistance test results, average particle diameter of adhesive colored resin granules, colored resin granules, adhesive resin granules (Comparative Examples 1 to 3 are colorant and resin particles), The form and the color tone of the handwriting are shown in the table below.

[0091]

[Table 1]

[0092]

[Table 2]

[0093]

[Table 3]

[0094]

[Table 4]

The symbols for determining the erasability and light scratch resistance in the table are as follows. Erasability ：: Erasable easily. Δ: Erasable up to 10 times, but slight handwriting remains. ×: Cannot be erased by rubbing up to 10 times. Light scratch resistance ：: Handwriting is hardly peeled off. Δ: Although handwriting is slightly peeled, handwriting can be sufficiently discriminated. X: Almost peeled off and handwriting could not be discriminated.

[0096]

According to the present invention, the particle distribution is 2 μm to 20 μm.
Of the adhesive colored resin granules contained in the range of 70% by weight or more, or the colored resin particles and the adhesive resin particles contained in the range of 70% by weight or more in the range of 2 μm to 20 μm. An ink composition that has extremely low permeability of the granular material to be applied to the inside of the paper, and also satisfies both the eraser erasability and light scratch resistance properties. In addition, the present invention can provide a writing eraser erasable water-based ink composition which satisfies both the handwriting retention that can be easily erased and the handwriting is not erased by the normal degree of rubbing between fingers or papers, and a writing instrument incorporating the same.

[Brief description of the drawings]

FIG. 1 is an enlarged vertical cross-sectional view of a handwriting written using the writing eraser-erasable aqueous ink composition of the present invention.

FIG. 2 is an enlarged vertical cross-sectional view of a handwriting written using another writing-erasable rubber-erasable aqueous ink composition of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Adhesive colored resin granule 2 Colored resin granule 3 Adhesive resin granule

Continued on the front page F-term (reference) 2C350 GA01 GA03 GA04 GA06 KD02 NA19 4J039 AB01 AB02 AB04 AB07 AB08 AB09 AB12 AD01 AD02 AD03 AD05 AD06 AD08 AD09 AD10 AD11 AD15 AE02 AE03 AE04 AE05 AE07 AE08 AE11 BA04 BA13 BA23 BA37 BA35 BA35 BA35 BC17 BC19 BC20 BC33 BC35 BC36 BC39 BC47 BC51 BC54 BC56 BC59 BC60 BD03 BE01 BE12 BE22 BE23 BE24 CA06 EA48 GA26 GA27

Claims (20)

[Claims] 1. An adhesive wherein at least a part of the surface of a colored resin particle composed of a pigment and an adhesive resin has tackiness, and the particle distribution of the particle is 70% by weight or more in the range of 2 μm to 20 μm. A writing eraser-erasable aqueous ink composition comprising at least a water-soluble polar solvent, water, and a water-soluble polar solvent. 2. The water-based ink composition for erasing eraseable writing according to claim 1, wherein the adhesive colored resin particles are contained in the ink composition in an amount of 5 to 35% by weight. 3. The water-based ink composition according to claim 1, wherein the weight ratio of the pigment contained in the adhesive colored resin particles is 2 to 30% by weight. 4. The aqueous ink composition according to claim 1, wherein the adhesive colored resin granules are granules prepared by a suspension polymerization method. 5. The adhesive resin in the adhesive colored resin granule prepared by the suspension polymerization method comprises a radically polymerizable monofunctional monomer and a polyfunctional monomer, and The weight ratio of the polyfunctional monomer is 2 to 10 per 100 monofunctional monomers.
The eraser-erasable aqueous ink composition for writing according to claim 4, which is a polymerized adhesive resin having a crosslinked structure. 6. The aqueous eraser erasable ink composition for writing according to any one of claims 1 to 5, wherein the adhesive colored resin particles have a glass transition temperature of less than 40 ° C. 7. An adhesive colored resin granule in which a pigment is dispersed in a homogeneous state in an adhesive resin.
A writing eraser-erasable water-based ink composition according to any of the preceding claims. 8. The adhesive colored resin granules are point-adhered to the paper surface in the handwriting after drying formed on the paper surface, and each of the adhesive colored resin granules is in an independent state or a point-adhered state. 8. The aqueous eraser-erasable water-based ink composition according to claim 1, which is present. 9. A colored resin granule containing a pigment, an adhesive resin granule, water, and a water-soluble polar solvent, each of which has a particle distribution of at least one of the colored resin granule and the adhesive resin granule. A writing eraser-erasable aqueous ink composition containing 70% by weight or more in the range of 2 μm to 20 μm. 10. The erasable aqueous eraser ink for writing according to claim 9, wherein the colored resin particles are particles obtained by polymerizing a polymerizable composition comprising at least a pigment and a radical polymerizable monomer under suspension polymerization conditions. Composition. 11. The colored resin granule is a granule obtained by melt-mixing a resin and a pigment and pulverizing the mixture by a pulverization method.
The eraser-based water-soluble ink composition for writing according to the above. 12. The eraser-erasable aqueous ink composition for writing according to any one of claims 9 to 11, wherein the weight ratio of the pigment to the resin forming the colored resin granules is 2 to 40 with respect to 1 pigment. . 13. The composition according to claim 9, wherein the adhesive resin particles are particles prepared by a polymerization method selected from a suspension polymerization method, a dispersion polymerization method, and a seed polymerization method. object. 14. A colored resin granule comprising 5 to 30% by weight and a sticky resin granule in a content of 0.5 to 15% by weight, wherein the weight ratio of the colored resin granule to the sticky resin granule is 1
The eraser-erasable aqueous ink composition for writing according to any one of claims 9 to 13, wherein the ratio is 00: 2 to 200. 15. The pressure-sensitive adhesive resin granules are present in a pointed state between particles and between particles and the paper surface in a handwriting after drying formed on the paper surface. The eraser-erasable aqueous ink composition for writing according to any one of the above. 16. A marking pen containing the eraser-erasable aqueous ink composition for writing according to any one of claims 1 to 15. 17. An ink composition comprising a shear-thinning agent, and having a viscosity at 100 rpm of 25 to 160 mP.
The eraser-erasable water-based ink for ballpoint pen writing according to any one of claims 1 to 15, which has a · s (value at 25 ° C of an EMD viscometer) and a shear thinning index of 0.1 to 0.7. Composition. 18. The eraser-erasable water-based ink composition for ball-point pen writing according to claim 17, wherein the particle distribution of all the particles contained in the ink composition is 80% by weight or more in the range of 2 μm to 10 μm. 19. The ball-point pen eraser-erasable aqueous ink composition according to claim 17 or 18, comprising an adhesive colored resin granule or a stabilizer for the adhesive resin granule. 20. A ball-point pen comprising the eraser-erasable water-based ink composition for writing a ball-point pen according to any one of claims 17 to 19.