JPH08248673A - Achromatic toner and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide an achromatic toner hardly causing any change in a tone of the achromatic toner and a tone of an image formed by using the achromatic toner by comprising two or more kinds of domains containing different kinds of pigments. CONSTITUTION: In an achromatic toner consisting of a matrix, in which a binding resin A is contained as a principal constituent, and domains, in each of which a visible rays - near infrared rays absorbing pigment, an achromatic agent, and a resin B are contained as principle constituents, the domains are constructed of at least two kinds of domains containing different kinds of pigments respectively. In this case, the different kinds of pigments are contained in the different domains individually, so that these different kinds of pigments are not mixed directly with each other, and as a result, a tone of the achromatic toner and a tone of an image can be prevented from the change due to interaction between the different kinds of pigments. On the other hand, fading retention rates and/or achromatic rates in the domains are regulated to be equal to each other, so that achromatization of an image can be unifomly carried out in a short time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decolorizable toner and a method for producing the same. More specifically, the present invention relates to a decolorizable toner capable of visualizing an electric latent image and an electric signal in electrophotography, an electrostatic recording material and the like, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, the reuse and recycling of used paper has been reviewed for the purpose of nature protection, particularly forest resource protection and waste reduction in urban areas. As part of this, the reuse of waste paper such as used copy paper, printed matter, and facsimile paper that has become unnecessary in the office of a company is being considered.

However, since most of these waste papers are company confidential documents which are generally regarded as trade secrets, these waste papers cannot be collected and recycled by a paper manufacturing company outside the company. It is extremely difficult, and since the recorded and printed parts of printed matter and copied materials cannot be easily erased, they must be incinerated or crushed for disposal, and such papers can be reused. Was considered virtually impossible. In addition, some studies have been conducted on the recycling of waste paper crushed by shredders, etc. However, since the strength of recycled paper manufactured using such crushed waste paper is generally low, for example, information paper, etc. There was a drawback that it could not withstand use as.

Therefore, as a method for easily and safely recycling these waste papers, copying is performed by using a decolorizable toner in which a binding resin contains a decolorizable dye having a property of decoloring by near infrared rays. After printing, it is proposed to erase the decolorizable toner by irradiating it with near infrared rays (JP-A-4-362935,
JP-A-5-119520).

[0005]

In order to obtain the desired hue of the decolorizable toner, it is conceivable to mix and use two or more types of decolorizable dyes.

However, when two or more kinds of the decolorizable dyes are mixed and used, the decolorizable dyes are different from the dyes and pigments used in the toner for the conventional coloring only. Since they have a special property of exhibiting color properties, when they are mixed with each other in different types, they exhibit an interaction and are formed using the color tone of the decolorizable toner and thus the decolorizable toner. The color tone of the image may change.

Further, since the color erasability and the image stability of the image formed by the color erasable toner differ depending on the type of the color erasable dye, the color erasability and the image stability of the formed image are uniform. It is difficult to obtain a decolorizable toner that exhibits

The present invention has been made to solve the above-mentioned problems, and even when two or more kinds of decolorizable dyes of different kinds are used in combination, the color tone of the decolorizable toner and A first object of the present invention is to provide a decolorizable toner that hardly changes the color tone of an image formed by using the decolorizable toner, and two or more types of decolorizable dyes of different types are used in combination. A second object is to provide a decolorizable toner that imparts a uniform decoloring property and image stability to the formed image even in the case.

[0009]

According to the present invention, firstly, a matrix containing a binding resin A as a main component, and a domain containing a visible light to near infrared absorbing dye, a decoloring agent and a resin B as a main component. The color-erasable toner according to claim 1, wherein the domain is at least two types of domains in which the types of the dyes are different from each other.

Secondly, the above-mentioned decolorizable toner in which the above-mentioned domains have substantially the same fading retention rate and / or decoloring rate.

Thirdly, the above decolorizable toner in which the binder resin A and the resin B are incompatible with each other.

Fourthly, there is provided a method of producing an erasable toner using the dye composition particles containing the dye, the erasing agent and the resin B as main components, wherein at least two kinds of dyes having different kinds of the dyes are used. The present invention relates to a method for producing a decolorizable toner, which comprises melting and kneading the composition particles and the binder resin A under heating, cooling the resulting mixture, and pulverizing the resulting kneaded material to a predetermined particle size.

Fifth, there is provided a method for producing an erasable toner using the dye composition particles containing the dye, the erasing agent and the resin B as the main components, wherein at least two kinds of dyes having different kinds of the dyes are used. A decolorizable toner characterized in that the composition particles and the toner particles containing the binder resin A as a main component are heated and melted and kneaded, and the resulting kneaded product is pulverized into a predetermined particle size. Regarding manufacturing method.

Sixth, the present invention relates to a method for producing the above-described decolorizable toner, in which the dye composition particles have substantially the same discoloration retention rate and / or decolorization rate.

Seventh, the dye composition particles have an average particle size of 5
And a method for producing the decolorizable toner having a thickness of ˜500 μm.

Eighth, it relates to a method for producing the above-described decolorizable toner in which the binder resin A and the resin B are incompatible with each other.

[0017]

Functions and Examples The decolorizable toner of the present invention comprises a matrix containing a binder resin A as a main component, a visible light to near infrared ray absorbing dye (hereinafter simply referred to as "dye"), a decoloring agent and a resin. A decolorizable toner including a domain containing B as a main component, wherein the domain is at least two types of domains having different types of the dye.

The decolorizable toner of the present invention has one major characteristic in that the above-mentioned domains are composed of at least two kinds of domains in which the kinds of the dyes are different from each other. Since these dyes are contained in different domains, the dyes of different types do not mix directly with each other.Therefore, the change in the color tone of the decolorizable toner due to the interaction between the dyes of different types, It is possible to prevent a change in color tone of an image formed using toner.

The decolorizable toner of the present invention is also characterized in that the fading retention rate and / or the decolorization rate of domains having different kinds of dyes are substantially equal to each other. The decoloring property of a dye depends on the type of the dye. In the decolorizable toner of the present invention, different types of dyes are contained in separate domains, and the fading retention rate and / or decolorization rate of the domains are adjusted to be approximately equal to each other. Therefore, the image formed by using the color erasable toner can be uniformly and rapidly erased in a short time.

Further, the decolorizable toner of the present invention is also characterized in that the binder resin A and the resin B are incompatible with each other. When different types of dyes are contained in different domains, and the resin B contained in the domains is incompatible with the binder resin A, contact between the domains via the binder resin A occurs. Since it is prevented, the respective domains are not directly mixed with each other, and direct contact between dyes having different kinds contained in the domains is eliminated. Therefore, it is possible to prevent a change in the color tone of the decolorizable toner and a change in the color tone of an image formed using the decolorizable toner due to the interaction between dyes of different types.

The first method for producing the decolorizable toner of the present invention is to melt-knead at least two kinds of dye composition particles having different kinds of dyes and the binder resin A, and cool the mixture to obtain a kneaded product. Is characterized in that is pulverized to a predetermined particle size. Dyes of different types are contained in separate dye composition particles, and the dye composition particles are used as the binder resin A.
By heat-melting and kneading, the dye composition particles become domains in the resulting decolorizable toner, and the binder resin A becomes a matrix. In addition, in the case of appropriately adjusting various properties of the obtained decolorizable toner, a toner property-imparting agent can be blended when the dye composition particles and the binder resin A are heated and melt-kneaded.

In the second method for producing the decolorizable toner of the present invention, two or more kinds of dye composition particles having different kinds of dyes and toner particles containing the binder resin A as a main component are heated and melted. It is characterized in that it is kneaded, cooled, and the obtained kneaded product is pulverized to a predetermined particle size. Different types of dyes 2
Since the dye composition particles of at least one kind and the toner particles containing the binder resin A as a main component are all particles, they can be rapidly melted and kneaded at the time of heat-melt kneading. Since it is possible to avoid applying unnecessary heat history to the dye, it becomes possible to prevent the dye from discoloring or fading by heating.

In the method for producing the decolorizable toner of the present invention, especially when the average particle size of the dye composition particles is 5 to 500 μm, the dye composition particles are rapidly melted to prevent unnecessary heat history. It is preferable because it can be used.

In the method for producing the color erasable toner of the present invention, there is also a feature in that adjustment is made so that the discoloration retention rate and / or the color erasure rate of each dye composition particle are approximately equal. When the fading retention rate and / or the erasing rate are adjusted in this way, as described above, the color tone of the image formed using the erasable toner is stabilized, and at the time of erasing the image, In this case, the color can be uniformly erased in a short time.

Further, in the method for producing the decolorizable toner of the present invention, when the binding resin A and the resin B are incompatible with each other, the dye is added via the binding resin A as described above. Since it is possible to prevent the composition particles from directly mixing with each other, it is possible to prevent a change in the color tone of the decolorizable toner and a change in the color tone of the image formed using the decolorizable toner due to the interaction between the dyes. be able to.

Further, the method for producing the decolorizable toner of the present invention is also characterized in that two or more kinds of dye composition particles having different kinds of dyes are used.

Conventionally, as a method of adjusting the color of the decolorizable toner, a method of mixing two or more kinds of dyes has been generally considered. However, when such a method is adopted and two or more kinds of dyes are mixed, the decoloring speed of the dye is
Since the dyes differ depending on the type, it is not possible to adjust the fading retention rate and / or the decolorization rate of the respective dyes to be approximately the same.

On the other hand, in the present invention, two or more kinds of dyes are used, but since each dye is dispersed in separate dye composition particles, the dye composition particles Percentage retention of dye contained in and /
Alternatively, it is easy to prepare each dye composition particle so that the decolorization rate becomes equivalent to the fading retention rate and / or the decolorization rate of the dye contained in the different kinds of toner particles. It has the advantage of being adjustable.

The domains constituting the decolorizable toner of the present invention are composed of dye, decolorizing agent and particles of dye composition containing resin B as a main component.

Examples of the dye include general formula (I):

[0031]

Embedded image

(In the formula, D ⁺ is a cation having absorption in the visible light region to the near infrared light region, and R ¹ , R ² , R ³ and R ⁴ are each independently an alkyl group, an aryl group or an allyl group. , Aralkyl group, alkenyl group, alkynyl group, silyl group,
A heterocyclic group, a substituted alkyl group, a substituted aryl group, a substituted allyl group, a substituted aralkyl group, a substituted alkenyl group, a substituted alkynyl group or a substituted silyl group) or a general formula (II): D ⁺ · A ⁻ (II) (In the formula, D ⁺ is a cation having absorption in the visible light region to the near infrared light region, A ⁻ is a halogen ion, a perchlorate ion,
Typical examples are cationic dyes represented by PF ₆ ⁻ , SbF ₆ ⁻ , BF ₄ ⁻ or sulfonate ion).

As the halogen ion, fluorine ion is used.
And chloride, bromide and iodide.
And as the sulfonate ion, for example, CH₃
SO₃ ^-Methyl sulfonate ion such as FCH₂S
O₃ ^-, F₂CHSO₃ ^-, F₃CSO₃ ^-, ClCH₂S
O₃ ^-, Cl₂CHSO₃ ^-, Cl₃CSO₃ ^-, CH₃OCH₂
SO₃ ^-, (CH₃)₂NCH₂SO₃ ^-Substituted methyls such as
Ruphonate ion, C₆H_FiveSO₃ ^-Such as phenyl sulfone
Acid ion, CH₃C₆H_FourSO₃ ^-, (CH₃)₂C₆H₃SO₃
^-, (CH₃)₃C₆H₂SO₃ ^-, HOC₆H_FourSO₃ ^-, (H
O)₂C₆H₃SO₃ ^-, (HO)₃C₆H₂SO₃ ^-, CH₃O
C₆H_FourSO₃ ^-, C₆H_FourClSO₃ ^-, C₆H₃Cl₂S
O₃ ^-, C₆H₂Cl₃SO₃ ^-, C₆HCl_FourSO₃ ^-, C₆Cl
_FiveSO₃ ^-, C₆H_FourFSO₃ ^-, C₆H₃F₂SO₃ ^-, C₆H₂F
₃SO₃ ^-, C₆HF_FourSO₃ ^-, C₆F_FiveSO₃ ^-, (CH₃)₂
NC₆H_FourSO₃ ^-Such as substituted phenyl sulfonate ion
Throw.

In the general formula (I), R ¹ ,
Specific examples of R ² , R ³ and R ⁴ include, for example, hydrogen atom, alkyl group, aryl group, allyl group, aralkyl group, alkenyl group, alkynyl group, silyl group, heterocyclic group, substituted alkyl group, substituted aryl group. , A substituted allyl group,
Examples thereof include a substituted aralkyl group, a substituted alkenyl group, a substituted alkynyl group and a substituted silyl group. Of these, preferred are, for example, hydrogen atom, phenyl group,
Anisyl group, ethoxyphenyl group, toluyl group, t-butylphenyl group, fluorophenyl group, chlorophenyl group, diethylaminophenyl group, xylyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-dodecyl group, cyclohexyl group, cyclohexenyl group, methoxymethyl group, methoxyethyl group, vinyl group, allyl group, triphenylsilyl group, dimethylphenylsilyl group, dibutylphenylsilyl group, trimethylsilyl group, piperidyl group Group, thienyl group, furyl group and the like. In addition, R ¹ , R ² , R ³
At least one of R ⁴ and R ⁴ is preferably an alkyl group having 1 to 12 carbon atoms. Among these alkyl groups, more preferred are those having 4 to 4 carbon atoms such as n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-dodecyl group and the like.
There are 12 alkyl groups. Specific examples of the anion include, for example, n-methyltriphenylboron ion,
n-ethyltriphenylboron ion, n-butyltriphenylboron ion, n-octyltriphenylboron ion, n-dodecyltriphenylboron ion, n
-Methyltri-p-tolylboron ion, n-ethyltri-p-tolylboron ion, n-butyltri-p-tolylboron ion, n-octyltri-p-tolylboron ion, n-dodecyltri-p-tolylboron ion, n -Methyltrianisylboron ion, n-ethyltrianisylboron ion, n-butyltrianisylboron ion, n-octyltrianisylboron ion,
n-dodecyltrianisylboron ion, di-n-methyldiphenylboron ion, di-n-ethyldiphenylboron ion, di-n-butyldiphenylboron ion, di-n
-Octyldiphenylboron ion, di-n-dodecyldiphenylboron ion, di-n-methyldi-p-tolylboron ion, di-n-ethyldi-p-tolylboron ion, di-n-butyldi-p-tolylboron ion, din-
Octyldi-p-tolylboron ion, di-n-dodecyldi-p-tolylboron ion, di-n-methyldianisylboron ion, di-n-ethyldianisylboron ion,
Di-n-butyldianisylboron ion, di-n-octyldianisylboron ion, di-n-dodecyldianisylboron ion, tetraphenylboron ion, tetraanisylboron ion, tetra-p-tolylboron ion,
Triphenylnaphthylboron ion, tri-p-tolylnaphthylboron ion, tetrabutylboron ion, trin-butyl (triphenylsilyl) boron ion, trin-butyl (dimethylphenylsilyl) boron ion, n-octyldiphenyl (di Examples thereof include n-butylphenylsilyl) boron ion and dimethylphenyl (trimethylsilyl) boron ion.

In the cationic dye represented by the general formula (I), preferred as the cation (D ⁺ ) are cyanine, triarylmethane, aminium, diimmonium, thiazine, xanthene, thiazine, oxazine and diallyl. Methane, triallylmethane,
Examples include styryl, pyrylium and thiopyrylium cationic dyes. Typical examples of such cationic dyes include those listed in Table 1-1 to Table 1-7.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

[Table 6]

[0042]

[Table 7]

In Tables 1-1 to 1-7, (1) Me represents a methyl group. (2) Et represents an ethyl group. (3) n-Bu represents an n-butyl group. (4) n-Hex represents an n-hexyl group. (5) n-Oct represents an n-octyl group. (6) Ar represents an aryl group. (7) Ph represents a phenyl group. (8) Tol represents a toluyl group. (9) Anisyl represents an anisyl group. (10) OMe represents a methoxy group.

The amount of the dye used is generally 0.0 to 100 parts (parts by weight, hereinafter the same) of Resin B used in the particles of the dye composition in order to impart sufficient colorability.
It is preferably 1 part or more, especially 0.1 part or more, and in order not to adversely affect the triboelectric charge amount inherent in the decolorizable toner obtained, the resin B10 is used.
It is preferably 25 parts or less with respect to 0 part, especially 15 parts or less. In the present invention, at least two kinds of dye composition particles having different kinds of dyes are used, and the amount of the dye used is the amount of all the dyes contained in all the dye composition particles. The resin B used for the dye composition particles is referred to as all the resin B used for all the dye composition particles. Therefore, the amount of the dye used in each of the dye composition particles may be appropriately adjusted in consideration of the color of the target decolorizable toner so that the amount of all the dyes used is within the above range. preferable.

In the present invention, two or more kinds of dyes are used, and the combination of such dyes is not particularly limited and may be appropriately adjusted according to the desired color and the like. Further, in the present invention, one type of dye is used in principle in one particle of each dye composition particle,
Dyes of different types may be used in combination as long as the dyes of different types do not interact with each other and the erasing speeds are approximately the same.

In the present invention, the decoloring property of the dye composition particles can be easily adjusted by adjusting at least one of the type of the resin B and the amount thereof used. In this case, it is preferable to adjust the type of the resin B and the amount thereof used within the range of the amount of the dye used for the resin B described above.

Examples of the resin B include homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like, and styrene-substituted homopolymers thereof.
Methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate Copolymer, styrene-octyl methacrylate copolymer, styrene-butyl acrylate-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-hydroxyethyl acrylate copolymer, styrene-acrylic acid ester- Hydroxyethyl acrylate copolymers, styrene-acrylic copolymers such as styrene-hydroxypropyl acrylate copolymers, styrene-acrylonitrile copolymers,
Styrene-acrylic rubber-acrylonitrile copolymer,
Styrene-EPDM-acrylonitrile copolymers, styrene-butadiene-acrylonitrile copolymers, styrene-chlorinated polyethylene-acrylonitrile copolymers and other styrene-acrylonitrile copolymers, styrene-p-chlorostyrene copolymers, styrene- Propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene- Other styrene-based copolymers such as butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, polyacrylic , (Meth) acrylic resin represented by polymethylmethacrylate, polybutylmethacrylate, polyhydroxymethylacrylate, polyhydroxyethylacrylate, polyhydroxypropylacrylate, polyhydroxymethylmethacrylate, polyhydroxyethylmethacrylate, polyhydroxypropylmethacrylate, etc. Polyester resins represented by saturated polyesters and unsaturated polyesters, ethylene-vinyl acetate copolymers, ethylene-vinyl acetate copolymers such as modified ethylene-vinyl acetate copolymers, olefin resins such as polyethylene and polypropylene , Epoxy resin, vinyl chloride resin, silicone resin, fluorine resin, polyamide resin, polyvinyl alcohol resin, polyurethane resin, polyvinyl chloride Butyral, rosin, modified rosin, rosin modified phenol formaldehyde resin, phenol formaldehyde resin, phenol resin, vinyl acetate resin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, Examples include paraffin wax and carnauba wax, but the present invention is not limited to these examples. These resins B are usually used alone or in admixture of two or more.

Among the specific examples of the resin B, for example, polyester resins, epoxy resins, (meth) acrylic resins, polyamide resins, polyvinyl alcohol resins, polyurethane resins, polyacrylonitrile resins, polyvinyl acetate resins. Resin, phenol resin, styrene-acryl copolymer, styrene-acrylonitrile copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, etc. A resin having a large polarity and having at least one group selected from the group consisting of a carbonyl group and a carbonyl group exhibits excellent anti-fading properties, and thus can be particularly preferably used.

The resins B used in the dye composition particles having different kinds of dyes are preferably incompatible with each other. As described above, when the resins B of the dye composition particles having different kinds of dyes are incompatible with each other, during the production of the decolorizable toner and the decolorization of the obtained decolorizable toner, , Because the dye composition particles having different kinds of dyes hardly mix with each other, there is no interaction between the dyes, and the fading retention rate and / or the decoloring rate of each dye composition particle are different from each other. Are not adversely affected by different dye composition particles and are stably held.

Among the specific examples of the resin B, a typical combination of incompatible resins is, for example, a combination of an olefin resin such as polypropylene or polyethylene and a polyester resin. However, such a combination can be particularly preferably used in the present invention.

Although there are various scales of incompatibility between resins, in the present invention, 0.2 g of each of two kinds of resins whose compatibility is to be evaluated is taken, and both resins are dissolved. It is dissolved in about 20 ml of a solvent that can be used, such as tetrahydrofuran or dichloromethane, and 10 ml of each resin solution is mixed,
Stir to obtain a uniform composition, cast the mixed solution on a glass plate such as a slide glass, and air-dry to remove the solvent to form a film having a thickness of about 1
When the turbidity of a 0 μm film on a glass plate is visually observed, white turbidity is recognized as a measure of incompatibility. When a resin which is hardly soluble or insoluble in an organic solvent is used, two kinds of resins are melted by heating, mixed so as to have a uniform composition, and then cooled to form a film. At this time, the fact that a phase-separated structure of these resins is observed by microscopic observation is used as a measure of incompatibility.

As the above-mentioned resin, in order to prevent discoloration during the production of the decolorizable toner, and to improve the weather resistance of the decolorizable toner obtained and the storage stability of the formed image, JIS
The acid value determined according to K0070 (1992) is 8
It is preferable to use mgKOH / g or more, especially 10 mgKOH / g or more. When the acid value is too large, the moisture resistance and the decoloring property are deteriorated, so that it is preferably 30 mgKOH / g or less, particularly 20 mgKOH / g or less.

Further, as the resin, in order to prevent color residue from being generated when an image formed using the obtained decolorizable toner is irradiated with visible rays to near infrared rays. In addition, the b * value in the L * a * b color coordinate by a color difference meter with a 30% ethyl acetate solution of the resin is 20 or less, preferably -20 to 20, and more preferably -5 to 5.
It is desirable to use 20.

In the present invention, the L * value, the a * value and the b * value are all values obtained by using a 30% ethyl acetate solution of the resin, a color difference meter “Z-Σ90” manufactured by Nippon Denshoku Industries Co., Ltd.
COLOR MEASURING SYSTEM ”.

As the L * value increases, the lightness increases, and as the L * value decreases, the lightness decreases. As the a * value increases, it becomes green, and as it decreases, it becomes red. Further, the b * value becomes yellow as it increases, becomes colorless as it approaches 0, and becomes blue as the negative value increases.

By the way, in the present invention, particularly b *
It is preferable that the value is 20 or less, and the b * value is 20.
If it is larger than this, the resin is colored yellow, and the yellow coloring adversely affects the hue of the image after decolorization.

In the present invention, the binder resin A and the resin B may be blended with wax such as polyolefin wax and paraffin wax, if necessary.

The amount of the wax to be blended is 0.1 part or more, preferably 0.5 part, relative to 100 parts of the resin B in order to sufficiently exert the effect of blending the wax, for example, the effect of preventing offset. Although it is desirable to set the above amount, when the amount of the wax is too large, film formation on the photoconductor that forms an electrical latent image tends to occur. 20 parts or less, preferably 10 parts or less.

In the present invention, examples of the decolorizing agent include those represented by the general formula (III):

[0060]

Embedded image

(Wherein R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently an alkyl group, an aryl group, an allyl group, an aralkyl group, an alkenyl group, an alkynyl group, a silyl group, a heterocyclic group or a substituted alkyl group. Group, substituted aryl group, substituted allyl group, substituted aralkyl group, substituted alkenyl group, substituted alkynyl group or substituted silyl group, Z ⁺ is a quaternary ammonium cation, a quaternary pyridinium cation, a quaternary quinolinium cation or a phosphonium cation The decoloring agent represented by (4) is a typical example.

Typical examples of the decoloring agent (boron-based compound) are, for example, tetramethylammonium n-methyltriphenylboron, tetramethylammonium n-butyltriphenylboron and tetramethylammoniumn.
-Octyltriphenylboron, tetramethylammonium n-dodecyltriphenylboron, tetramethylammonium n-methyltri-p-tolylboron, tetramethylammonium n-butyltri-p-tolylboron, tetramethylammonium n-octyltri-p-
Tolylboron, tetramethylammonium n-dodecyltri-p-tolylboron, tetramethylammonium n
-Methyltrianisylboron, tetramethylammonium n-butyltrianisylboron, tetramethylammonium n-octyltrianisylboron, tetramethylammonium n-dodecyltrianisylboron, tetraethylammonium n-methyltriphenylboron, tetraethylammoniumn-butyl Triphenylboron, tetraethylammonium n-octyltriphenylboron, tetraethylammonium n-dodecyltriphenylboron, tetraethylammonium n-methyltri-p-tolylboron, tetrabutylammoniumn
-Butyltriphenylboron, tetraphenylphosphonium di-n-butyldianisylboron, tetraanisylphosphoniumdi-n-butyldianisylboron and the like can be mentioned. These decolorizers can be used alone or in admixture of two or more.

The amount of the decolorizing agent used is preferably 1 part or more per 100 parts of the dye, especially 5 parts or more, in order to improve the decoloring property. In order to improve the light resistance of the printing and images formed by using it and prevent discoloration or fading, etc., 2500 parts or less per 100 parts of the dye, especially 100 parts of the dye.
It is preferably 0 part or less.

The dye composition particles are prepared by, for example, dispersing or dissolving a predetermined amount of a dye, a decoloring agent and a dye composition containing resin B as a main component in an organic solvent, and then mixing or kneading the mixture and then the organic solvent. Can be prepared by volatilizing and removing and pulverizing to a predetermined particle size.

The boiling point of the organic solvent is preferably below the decomposition temperature of the dye under 1 atm. Here, if the boiling point of the organic solvent is higher than the decomposition temperature of the dye, it is difficult to distill off the solvent under reduced pressure, and the decomposition of the dye occurs.

Specific examples of the organic solvent include alcohol solvents such as methanol, ethanol, isopropanol and butanol; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; nitrile solvents such as acetonitrile; ethyl acetate and acetic acid. Ester solvent such as butyl; ether solvent such as diethyl ether, tetrahydrofuran, dimethoxyethane, anisole; amide solvent such as dimethylformamide; amine solvent such as triethylamine; aromatic solvent such as benzene, toluene, xylene, chlorobenzene Solvents: Halogenated hydrocarbon solvents such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, trichlene, perklene, etc. Are, acetone Among these, methyl ethyl ketone, methanol, ethanol, acetonitrile, tetrahydrofuran, benzene, toluene, xylene, dichloromethane, chloroform, dichloroethane are preferred. These organic solvents can be used not only alone but also as a mixed solvent.

The amount of the organic solvent is usually 10 parts or more, preferably 20 parts or more, relative to 100 parts of the resin B in order to sufficiently dissolve the dye, and an excess amount is required for removing the organic solvent. In order to avoid cost, it is usually 5000 parts or less relative to 100 parts of resin B,
It is preferably 3000 parts or less.

First, the dye composition containing the dye, the decoloring agent and the resin B as a main component is dissolved in an organic solvent, mixed or kneaded, and the organic solvent is removed from the obtained mixture to obtain a dried product. To be

The obtained dried product is treated with, for example, a hammer mill,
Dye composition particles can be obtained by coarsely pulverizing with a cutter mill or the like, and if necessary, finely pulverizing with, for example, a jet pulverizer, and classifying if necessary.

If the average particle size of the dye composition particles is too small, the cost for crushing increases, and uniform heat-melt kneading with the binder resin A tends to be difficult, It is preferably 5 μm or more, especially 15 μm or more, and when it is too large, uniform heat-melt kneading with the binder resin A tends to be difficult, so 500 μm or less, especially 200 μm
m or less. Incidentally, the average particle size of the dye composition particles, about 50 particles of the dye composition particles are arbitrarily selected, after measuring the individual particle size by microscopic observation,
It can be obtained by obtaining the average value.

In the present invention, two or more kinds of dye composition particles having at least different kinds of dyes can be prepared according to the above method for each kind of dye.

At least one of the dye composition particles is adjusted depending on the retention of fading and / or the type and amount of the resin B used in the dye composition particles, and the decolorizer and amount thereof. It can be adjusted by

The fading retention rate and / or the decolorization rate of each dye composition particle are set so that the color tone of an image formed by using the obtained decolorizable toner does not change and the color is erased in a short time. It is preferable that both are approximately equivalent.

The discoloration retention rate and the decolorization rate of the dye composition particles can be measured according to the following methods.

(A) Retention of fading The dye composition particles are dissolved in an organic solvent such as dichloromethane or acetone, coated on an overhead print film, and air-dried to give a film thickness of about 10
A coating film of μm is formed. The reflection density (density A) of the formed coating film is measured with a Macbeth densitometer.

Next, the coating film was irradiated with a light beam by a fluorescent lamp so that the irradiation surface had a light intensity of 1100 lux, and the light was irradiated for a predetermined time (T
After standing for a time, the reflection density (density B) was measured in the same manner as described above, and the fade retention rate (DT) was calculated according to the formula: [Discoloration retention rate (DT)] = [density B / density A] × 100. Ask.

In the present invention, the fact that the fading retention ratios of the dye composition particles are approximately the same in each case means that the fading ratio of the dye composition particles A after the elapse of the fluorescent light irradiation time T is D ( A) T, and D (B) T is the fading rate of the dye composition particles B after fluorescent lamp irradiation for T hours, | D
(A) T-D (B) T | means about 10% or less, preferably about 5% or less. The irradiation time T is
A maximum of 24 hours is sufficient.

(B) Decoloring rate The dye composition particles are dissolved in an organic solvent such as dichloromethane or acetone, coated on an overhead print film and then air-dried to give a film thickness of about 10 μm.
m to form a coating film. The reflection density (density A) of the formed coating film is measured with a Macbeth densitometer.

Next, the coating film was irradiated with near infrared rays (2 W / cm ² ) with a halogen lamp for a predetermined time (T time),
After the color was erased, the reflection density (density B) was measured in the same manner as described above, and the formula: [Decoloration rate (Et)] = [(density A-density B) / density A]
The erasing rate (Et) is calculated according to × 100.

In the present invention, near-infrared rays are converted into 100
When the decolorization rate (Et) after irradiation for a second is 95% or more, it can be said that the decolorizing property of each dye composition particle is good.
Further, the fact that the decolorization rates of the dye composition particles are approximately the same in each case means that the decolorization rate of the dye composition particles A after the time T of near infrared irradiation is E (A) T, and The decolorization rate of the composition particles B after the near-infrared irradiation T time has elapsed is E
(B) T means that | E (A) T−E (B) T | is about 10% or less, preferably about 5% or less.

The decolorizable toner of the present invention uses the above-mentioned dye composition particles, and heat-melts and kneads at least two kinds of dye composition particles having different kinds of the dyes and the binder resin A, and cools. A method of pulverizing the obtained kneaded product to a predetermined particle size (hereinafter referred to as the production method I), for at least two kinds of dye composition particles having different kinds of the dyes, and a toner containing a binder resin A as a main component. It can be prepared by a method of heating and melting and kneading the particles, cooling and kneading the obtained kneaded product to a predetermined particle size (hereinafter referred to as production method II).

Binder resin A used in the above Invention I
As the resin B used in the particles of the dye composition
The same is exemplified.

When a resin that is incompatible with the resin B is used as the binder resin A, it is possible to prevent the dye composition particles from directly mixing with each other through the binder resin A. It is possible to prevent a change in the color tone of the decolorizable toner due to the interaction between the dyes, and a change in the color tone of the image formed using the decolorizable toner.

A typical example of a combination in which the binder resin A and the resin B are incompatible with each other is, for example, a combination of a styrene-acrylic acid ester copolymer and a polyester resin. .

In the above Production Method Invention I, when the dye composition particles and the binder resin A are heated and melted and kneaded, an appropriate amount of the toner property imparting agent described later can be added.

The heating temperature for heating, melting and kneading the dye composition particles and the binder resin A is usually at least the melting temperature of the resin B and the binder resin A used in the dye composition particles, and the heat of the dye It is preferable to set the temperature within the range of the decomposition temperature or less in order to perform stable heating, melting and kneading.

The heat-melting and kneading can be usually carried out by using a kneader, a roll, a kneading extruder, etc. After kneading so as to obtain a uniform composition, after cooling,
The obtained kneaded product is crushed to a predetermined particle size. When crushing, for example, a cutter mill, a jet crusher or the like can be used. After crushing, if necessary, a wind classifier or the like may be used for classification so that a predetermined particle size is obtained. Good.

The toner particles used in the above-mentioned Production Method II contain the binder resin A as a main component. As the binding resin A, the same resins as those used in the above-mentioned production method invention I are exemplified. The toner particles only need to have the binder resin A as a main component, and the toner characteristic imparting agent described below can be added in an appropriate amount as the other component.

The toner particles are prepared by heating, melting, and kneading the binder resin A and, if necessary, the toner property-imparting agent, cooling the mixture, and then pulverizing the binder resin A and, if necessary, dissolving the toner property-imparting agent in an organic solvent. It can be prepared by, for example, a method of kneading and volatilizing and removing the organic solvent, and then pulverizing, and when the binding resin A is used alone, the binding resin A is pulverized as it is.

If the average particle size of the toner particles is too small, the cost tends to increase, so it is preferably 20 μm or more, especially 50 μm or more, and when it is too large. Since it tends to be difficult to uniformly heat-melt and knead the dye composition particles, it is preferably 1000 μm or less, more preferably 500 μm or less.

In the above production method invention II, since the dye composition particles and the toner particles are both particulates, they can be rapidly dissolved and kneaded at the time of heat-melt kneading, and are contained in the dye composition particles. Since it is possible to largely prevent unnecessary heat history from being applied to the formed dye, there is an advantage that it is possible to prevent the dye from discoloring or fading by heating.

In Production Method Invention II, the heat-melt kneading, pulverization of the obtained kneaded product, adjustment of the particle size and the like may be performed in the same manner as in Production Method Invention I.

Examples of toner property imparting agents that can be used in Production Method Inventions I to II include charging substances, anti-fading agents, white fillers, ultraviolet absorbers, plasticizers and lubricants.

Typical examples of the above-mentioned chargeable substance include charge control agents.

Examples of the charge control agent include positive charge control agents such as quaternary ammonium salts, alkylamides and hydrophobic silica; diaminoanthraquinone, chlorinated polyolefins, chlorinated polyesters, naphthenic acid metal salts, fatty acid metal salts. Examples include negatively charged charge control agents and the like.

The charge control agent is generally available as a commercial product, and a typical example of such a product is Bontron P-51 (Orient Chemistry) which is a positive charge control agent of a quaternary ammonium salt. Industry Co., Ltd.
), TP-415 (manufactured by Hodogaya Chemical Co., Ltd.), negative charge control agent Kayacharge N-3 (manufactured by Nippon Kayaku Co., Ltd.), and calixarene negative charge control agent. Bontron E-89 (Orient Chemical Industry Co., Ltd.)
Made) etc.

The blending amount of the above-mentioned chargeable substance may be appropriately adjusted according to the charge amount of the target decolorizable toner. In addition, when the amount of charging substance is too large,
The resulting decolorizable toner tends to have poor moisture resistance and poor image stability. Therefore, if the total amount of the binder resin A and the resin B is 100 parts or less, 20 parts or less, particularly 8 parts or less is preferable. If it is desired to impart a certain degree of chargeability, the amount of the above-mentioned chargeable substance to be blended is 0.3 part or more based on 100 parts of the total amount of the resin A and the resin B for binding, and especially 1 It is preferably not less than part.

When the decolorizable toner of the present invention is preliminarily blended with an anti-fading agent, it is possible to prevent a decrease in the image density of the printed or copied image of the decolorizable toner. This is because the reaction and decomposition of the dye in the decolorizable toner due to light and heat are suppressed.

The anti-fading agent used in the present invention has the function of preventing the dye from fading, discoloring and fading. In the present invention, the anti-aging agent, the metal oxide and the metal soap are used. At least one selected can be used. Although the reason why the anti-fading agent used in the present invention exhibits such anti-fading action is not clear, it is likely that the heat-resistant anti-aging agent has a phenolic hydroxyl group, and the metal oxide has a basic polar surface. It is considered that the groups are present, and that the metal soap is due to the presence of ionic polar groups such as a carboxyl group.

That is, the dye used in the present invention is an ionic complex, and the presence of the polar group of the anti-fading agent stabilizes the ion pair of the dye complex, and therefore the stability of the dye against light and heat. Is believed to increase. Therefore, due to this property, when the above-mentioned heat-resistant antiaging agent, metal oxide or metal soap is present at the same time as the dye used in the present invention, the dye becomes stable and is prevented from fading, discoloring and fading. It is considered to be a thing.

Specific examples of the heat resistant anti-aging agent include:
For example, 2,5-di-t-amylhydroquinone, 2,5
-A hydroquinone derivative-based antiaging agent such as di-t-butylhydroquinone and hydroquinone monoethyl ether; p
-Methyl hydroxybenzoate, ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, 3,4-hydroxyphenyl-P -Tolyl sulfone, methyl gallate, ethyl gallate, stearyl gallate, n-propyl gallate,
Lauryl gallate, resorcinol, 1-oxy-3-
Methyl-4-isopropylbenzene, 2,6-di-t-
Butylphenol, 2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-sec-butylphenol, butylhydroxy Anisole, 2,6-
Anti-aging of alkylated phenols such as di-t-butyl-α-dimethylamino-p-cresol, 2- (1-methylcyclohexyl) -4,6-dimethylphenol, styrenated phenols, alkylated phenols and phenol derivatives Agents: 1,1,3-tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 4,4'-butylidenebis- (3-methyl-6-t
-Butylphenol), 2,2-thiobis (4-methyl-6-t-butylphenol), n-octadecyl-3
-(4'-Hydroxy-3'-5'-di-t-butylphenylpropionate and other hindered phenolic antioxidants; tris (nonylphenyl) phosphite, tris (mixed mono- and di-nonylphenyl)) Phosphite, phenyldiisodecylphosphite, diphenylmono (2-ethylhexylphosphite, diphenylmonotridecylphosphite, diphenylisodecylphosphite, diphenylisooctylphosphite, triphenylphosphite, tris (tridecyl) phosphite, tetraphenyl Examples include phosphite-based antioxidants such as dipropylene glycol phosphite, and these heat-resistant antioxidants may be used alone or in admixture of two or more. Then p-hid Methyl oxybenzoate, propyl p-hydroxybenzoate, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, 3,4-hydroxyphenyl-p-tolylsulfone, methyl gallate, Ethyl gallate, stearyl gallate, n-propyl gallate, lauryl gallate, resorcinol and the like are preferable because of their excellent transparency, whiteness and solubility in a binder resin.

The heat-resistant anti-aging agent may be blended with either the resin A for binding or the resin B for binding, but in order to give the dye sufficient color resistance, the resin with which the dye is blended is added. It is preferable to mix it with B.

When the resin B is blended with a heat resistant anti-aging agent, the amount of the heat resistant anti-aging agent blended is 0.02 part with respect to 100 parts of the resin B in order to sufficiently exhibit the anti-fading property. It is desirable that the amount is at least 0.3 part, preferably at least 0.3 part. Further, in order to uniformly disperse the heat resistant anti-aging agent in the resin B, the amount of the heat resistant anti-aging agent blended is 200 parts or less, preferably 150 parts or less, relative to 100 parts of the resin B. desirable.

In order not to affect the triboelectric charge amount of the decolorizable toner obtained, the heat resistant antioxidant is blended in a sum of 1 for the binder resin A and 1 for the resin B.
It is desirable that the amount is 10 parts or less, preferably 7 parts or less with respect to 00 parts.

Specific examples of the metal oxide include, for example, MgO, Al ₂ O ₃ , SiO ₂ , Na ₂ O and SiO ₂ .M.
gO, SiO ₂ · Al ₂ O ₃ , Al ₂ O ₃ · Na ₂ O · C
Examples thereof include O ₂ and MgO.Al ₂ O ₃ .CO _2. These metal oxides may be used alone or in admixture of two or more. Among these metal oxides, MgO, MgO
And SiO ₂ mixture, MgO and Al ₂ O ₃ mixture, N
a ₂ O, SiO ₂ · MgO, SiO ₂ · Al ₂ O ₃ , Al ₂ O
_{3, Na 2 O · CO 2} , such as _{MgO · Al 2 O 3 · CO} 2 is the at preferable that particularly excellent in anti-fading property.

The metal oxide may be blended with either the resin A or the resin B for binding, but in order to impart sufficient color resistance to the dye, the resin B with which the dye is blended is added.
It is preferable to mix it with.

When a metal oxide is blended with the resin B, the amount of the metal oxide blended is 1 part or more, preferably 3 parts with respect to 100 parts of the resin B, in order to sufficiently exhibit the anti-fading property. The above is desirable. Further, in order to uniformly disperse the metal oxide in the resin B, the compounding amount of the metal oxide is 300 with respect to 100 parts of the resin B.
It is desirable that the amount is not more than part, preferably not more than 150 part.

If the amount of the metal oxide compounded is too large, the color density of the printed matter tends to be low, so 30 parts are added to 100 parts of the binder resin A and the resin B in total. Hereafter, it is desirable to adjust the amount to be preferably 15 parts or less.

By the way, when the amount of the metal oxide compounded is 1 part or more based on 100 parts by weight of the resin A and the resin B for binding, the color is erased on the white copying paper generally used for electrophotography. After forming an image using a volatile toner, when the image is erased by irradiating visible light to near infrared rays,
The erased image portion has the same color on the copy paper, and further suppresses the gloss unique to the binder resin A and the resin B, and exhibits the same gloss as the copy paper. There is an advantage that it can not be distinguished from. Such an advantage is remarkable when a metal oxide containing MgO or SiO ₂ is used among the above metal oxides, and a metal oxide containing MgO, a metal oxide containing SiO ₂ or a metal oxide containing them. The mixture and the like do not hinder the color developability of the decolorizable toner during printing and image formation, and therefore can be particularly preferably used in the present invention.

If the average particle size of the metal oxide as the anti-fading agent is too large, the quality of the image may be impaired. Therefore, it is preferably 5 μm or less, especially 2 μm or less. . The shape and color of the particles are not particularly limited, but in order to eliminate the gloss of the resin A and the resin B for binding and to eliminate the traces when the formed prints and images are erased, the shape of the particles is A spherical or elliptical shape is desirable, and the color is generally white because the color of electrophotographic copying paper is generally white.

Specific examples of the metal soap include stearates such as lithium stearate, magnesium stearate, aluminum stearate, calcium stearate, strontium stearate, barium stearate, zinc stearate, cadmium stearate and lead stearate. Acid salts; lauric acid salts such as cadmium laurate, zinc laurate, calcium laurate, barium laurate; chlorostearate salts such as calcium chlorostearate, barium chlorostearate, cadmium chlorostearate, barium 2-ethylhexylate, 2 2-zinc ethylhexylate, cadmium 2-ethylhexylate, 2-ethylhexylates such as lead 2-ethylhexylate; barium ricinoleate,
Ricinoleate such as zinc ricinoleate and cadmium ricinoleate; Formula: 2PbO.Pb (C ₁₇ H ₃₅ COO) ₂
Dibasic lead stearate and the like; salicylate lead, zinc salicylate, tin, salicylates such as salicylic acid chromium; _{formula: 3PbO · Pb (C 8 H} 4 O 4) · H 2 O tribasic maleic lead such Formula: 2PbO · Pb (C ₈
H ₄ O ₄₎ and dibasic phthalic acid lead such, and these metal soaps may be used alone or in combination. Among these metal soaps, zinc stearate, calcium stearate, magnesium stearate, zinc laurate, lead salicylate, zinc ricinoleate, barium ricinoleate, barium 2-ethylhexylate, etc. are used for whiteness and toner. It is preferable because it has a suitable melting point.

The above-mentioned metal soap may be blended with either the resin A or the resin B for binding, but in order to sufficiently impart color resistance to the dye, it is blended with the resin B with which the dye is blended. Preferably.

When the resin B is blended with a metal soap, the amount is preferably 0.05 part or more, and more preferably 0.1 part or more, relative to 100 parts of the resin B in order to sufficiently exhibit the anti-fading property. . In order to uniformly disperse the metal soap in the resin B, the blending amount of the soap is
It is desirable that the amount is 200 parts or less, preferably 150 parts or less, relative to 100 parts.

The amount of the metal soap blended does not adversely affect the triboelectric charge amount of the color erasable toner, so that bleeding does not occur on the surface of the color erasable toner. Sum of resin A and resin B used for binding 1
It is desirable that the amount is 10 parts or less, preferably 5 parts or less with respect to 00 parts. In some cases, it has been known that the addition of a dispersant improves the dispersibility of the white filler and improves the whiteness of the image after being erased by the decolorizable toner.

The white filler can be used as a decoloring auxiliary component.

Specific examples of the white filler include titanium oxide, calcium carbonate, alumina, zinc white, magnesium oxide, magnesium hydroxide, clay and fine powder silicon. These white fillers may be used alone or in combination.
It is used as a mixture of two or more species. Among these white fillers, titanium oxide, calcium carbonate, zinc white, and the like are preferable because they have excellent coloring properties.

The amount of the white filler to be blended is 0.2 parts or more, more preferably 1 part or more with respect to 100 parts of the binder resin A and the resin B in order to bring out the effect of blending the white filler. Is desirable.
If the amount of the white filler is too large, the color density peculiar to the toner tends to be low.
It is desirable that the amount is 50 parts or less, preferably 30 parts or less, based on 100 parts of the resin B.

Specific examples of the lubricant include silicone oil, food oil, animal oil, process oil and the like. The blending amount of the above-mentioned lubricant is a sum of the binder resin A and the resin B used in the decolorizable toner in order to sufficiently bring out the effect of blending such a lubricant.
0.01 part or more with respect to 00 parts, and more preferably,
It is desirable that the content be 0.03 parts or more. If the amount of such a lubricant is too large, the image quality of the toner tends to be adversely affected. Therefore, 2 parts or less per 100 parts of the total amount of the binder resin A and the resin B used in the decolorizable toner is used. It is desirable that the amount be 0.5 parts or less.

If the ratio of the dye composition particles to the binder resin A (dye composition particles / binder resin A: weight ratio) is too small, the resulting decolorizable toner has poor coloring properties. Since it tends to become difficult, it is preferable to set it to 5/95 or more, especially 8/92 or more. If it is too large, it tends to be difficult for the dye composition particles to phase separate from each other. It is preferably / 50 or less, especially 45/55 or less.

The decolorizable toner of the present invention is obtained by the above-mentioned Production Method I.
To II, and includes a matrix containing the binder resin A as a main component and a domain composed of at least two kinds of dye composition particles having different kinds of dyes.

Therefore, the decolorizable toner of the present invention is
The dye has a structure in which a dye and a decoloring agent are contained in the “domain” that constitutes the “island”, and
However, it has a structure in which the binder resin A is dispersed in a “matrix” which constitutes “sea”.

The decolorizable toner of the present invention is, after printing and fixing on an image support made of, for example, paper, irradiated with visible rays to near infrared rays by means of, for example, a semiconductor laser, a halogen lamp, a light emitting diode or the like. By this, the printed portion can be erased. And
After the printed portion is erased, it is possible to print again by overlapping the erased portion again.

Therefore, the decolorizable toner of the present invention can be used for an image support such as a copy sheet, a ticket that can be printed at the time of boarding and erased at the time of getting off, and can be repeatedly used. It is also suitable for use in printing of paper pieces.

Next, the decolorizable toner of the present invention and the method for producing the same will be described in more detail based on examples, but the present invention is not limited to these examples.

Production Example 1 (Production of Dye Composition Particles) As a resin B, a polyester resin (manufactured by Kao Corporation, NE
-1110, hereinafter referred to as REB), as the dye has the formula:

[0126]

Embedded image

Dye represented by (hereinafter referred to as DYA)
Or expression:

[0128]

[Chemical 4]

Dye represented by the following (hereinafter referred to as DYB), tetrabutylammonium n-butyltriphenylboron (hereinafter referred to as SEA) as a decoloring agent, and 2,2-bis (4-hydroxyphenyl) propane as an anti-fading agent. (Hereinafter, referred to as AOA), dichloromethane (hereinafter referred to as OSA) as an organic solvent, mixed at a ratio shown in Table 2 and sufficiently dispersed or dissolved, and the resulting mixed solution was vacuum-heated dryer ((Ltd.)). Ogawara Seisakusho, VB-1
01) After drying by using, The obtained dried product was pulverized with a cutter mill, the average particle size to give a dyestuff composition particles of 20 [mu] m X ₁ to X ₃ and Y ₁ to Y _3.

As the physical properties of the obtained dye composition particles, the retention of fading and the erasing rate were examined. The results are shown in Table 2.

[0131]

[Table 8]

Next, the relationship between the elapsed time (hr) and the fading retention rate (%) was examined based on the measurement results of the fading retention rate shown in Table 2. The results are shown in FIGS.

From the results shown in FIGS. 1 and 2, as the dye / decolorant (molar ratio) becomes smaller, the discoloration retention rate greatly decreases. In FIG. Ratio is 1/3 or more (X ₁ in FIG. ₁ ), and in FIG. 2, the dye / decoloring agent (molar ratio) is 1/5 or more (Y ₁ , Y _{2 in} FIG. 2). It can be seen that the degree of reduction in the retention of discoloration is small, which is preferable.

3 to 4 show the relationship between the light irradiation time and the erasing rate when measuring the erasing rate.

From the results shown in FIG. 3, when the dye / decoloring agent (molar ratio) is 1/3 or less (X _{1 to} X _{3 in} FIG. ₃ ),
It can be seen that the image can be erased with a high erasing rate of about 95% or more after 100 seconds have elapsed.

From the results shown in FIG. 4, when the dye / decoloring agent (molar ratio) is 1/5 or less (Y _{2 in} FIG. 4),
It can be seen that the image can be erased with a high erasing rate of about 95% or more after 100 seconds have elapsed.

Production Example 2 (Production of Toner Particles) A styrene-butyl acrylate-butyl methacrylate copolymer (manufactured by Mitsui Toatsu Kagaku Co., Ltd., as a binder resin A)
CRP-200) 75.0% by weight, polypropylene wax (manufactured by Mitsui Chemicals, Inc., Viscole 660P) 5.
0 parts by weight, silicone oil (Toray Silicone Co., Ltd.)
Manufactured by KF-96H), titanium oxide (Showa Denko KK, STR-60) 0.7 parts by weight, and zinc stearate 0.2 parts by weight are mixed, and a kneading extruder is used. The mixture was heated and kneaded at about 140 to 150 ° C. to obtain a uniform composition, which was then cooled to obtain a lump.

The obtained lump was crushed using a cutter mill and a jet crusher to obtain toner particles having an average particle diameter of 50 μm (hereinafter referred to as REA).

Example 1 15 parts by weight of the dye composition particles X ₁ obtained in Preparation Example 1,
Dye composition particles Y ₂ were used in an amount of 10 parts by weight, and 80 parts by weight of the toner particles (REA) obtained in Production Example 2 were thoroughly mixed with a mixer, and then about 1 part was obtained using a kneading extruder.
The mixture was heated and melted and kneaded at 20 to 140 ° C., and cooled to obtain a lump.

The obtained lumps were crushed with a cutter mill and a jet crusher and then classified with an air classifier to obtain a decolorizable toner having an average particle size of 15 μm.

Next, 100 parts by weight of the obtained decolorizable toner was added to finely powdered silica (HVK manufactured by Hoechst Japan KK).
-2150) 0.4 parts by weight was uniformly mixed using a mixer to obtain a mixture. 5 parts by weight of this mixture and a silicone resin coated ferrite carrier (Powder Tech Co., Ltd.)
Manufactured by F95-100) was uniformly mixed using a V-type blender to obtain a two-component developer.

The obtained two-component type developer was set in a commercially available copying machine (FT-4525, manufactured by Ricoh Co., Ltd.), and copying was performed using a black solid as an original. Using the Macbeth densitometer, measure the reflection density of the obtained copy printed matter X1.
The measurement was performed at 0 points, and the average value was defined as x1.

Then, the copy printed matter was set again in the paper tray, and copy printing was performed again so that the images were overlapped, that is, the toner layers were overlapped. Obtained copy print X
The reflection density of 2 was measured by the above method, and the value was defined as x2.

When | x2-x1 | ≦ 0.05, the copy print X2 was used as an evaluation image sample.

In the case of | x2-x1│> 0.05, the above-mentioned re-copying operation is repeated to compare the reflection density xi of the copy-printed image Xi with the previously measured reflection density xi-1. , | Xi−xi−1 | ≦ 0.05, the copy print Xi was used as an evaluation image sample. As the physical properties of the color erasable toner, the image stability, background fog density, color erasability and color tone stability of the image were examined according to the following methods.

(1) Image Stability The reflection density of the evaluation image sample of the obtained decolorizable toner was measured as a density A using a Macbeth densitometer. The sample was left on the illuminated surface under a fluorescent lamp of 1100 lux for 24 hours, and the reflection density was defined as the density B, and the measurement was performed in the same manner as described above. Formula: (Fade retention rate) = (density B) / (density The fading retention rate was obtained according to A) × 100, and the image stability was evaluated based on the following evaluation criteria.

(Evaluation Criteria) A: fading retention rate is 80% or more B: fading retention rate is 60% or more and less than 80% C: fading retention rate is 40% or more and less than 60% D: fading retention rate is less than 40% ( 2) Background fogging density A white image was used as a document to make a sample image of both decolorized toners, and the image density on the surface was measured with a reflectometer (Tokyo Denshoku Co., Ltd.).
Manufactured by TC-6DS). Separately from this, the image density on the paper surface before copying was similarly measured. The value obtained by subtracting the value on the paper surface from the obtained sample value is taken as the background fog density. The closer this value is to 0, the less ground fogging is determined.

(Evaluation Criteria) A: Ground fog density is less than 0.03 B: Ground fog density is 0.03 or more and less than 0.06 C: Ground fog density is 0.06 or more and less than 0.10 D: Ground The fogging density is 0.10 or more. (3) Decoloring property The obtained decoloring toner evaluation image sample is set to an ambient temperature of 6
It was left in a constant temperature bath of 0 ° C. and was irradiated with light from a halogen lamp. As the halogen lamp, a double end type halogen lamp (manufactured by USHIO INC.,
QRZ 85-400 banfi), voltage 85
V and color temperature of 3190K were set. The halogen lamp was installed at a position 10 cm from the surface of the evaluation image sample in a constant temperature bath.

After the evaluation image sample was left for 3 minutes or more, the halogen lamp was turned on for a predetermined time. The reflection density of the light-irradiated product was measured as the density C using a Macbeth densitometer, and when the condition of the density C ≦ 0.15 was satisfied, it was determined that the color was erased. The predetermined time here is 10, 20, 3
It was set to 0 or 60 seconds.

(Evaluation Criteria) A: Color disappeared after the lamp was turned on for 10 seconds. B: The lamp disappears in 20 seconds, but does not disappear in 10 seconds. C: Color disappears after 30 seconds of lamp lighting, but does not disappear after 20 seconds. D: Color disappears in 60 seconds, but not in 30 seconds. E: Color does not disappear even when the lamp is on for 60 seconds.

(4) Stability of image color tone The image hue (C
L ₀ ) was examined according to JIS-Z8721-1977.

Next, after the sample was left under a fluorescent lamp of 100 lux for 5 hours, the image hue (CL ₁ ) of the sample was examined, and the color tone stability of the image was evaluated based on the following evaluation criteria. did.

(Evaluation Criteria) A: | CL ₁ −CL ₀ | is less than 0.5 B: | CL ₁ −CL ₀ | is 0.5 or more and less than 1.0 C: | CL ₁ −CL ₀ | 1.0 or more and less than 1.5 D: | CL ₁ −CL ₀ | is 1.5 or more Comparative Example 1 In Example 1, 15 parts by weight of the dye composition X ₁ and 10 parts by weight of the dye composition particles Y ₂ are contained. Instead, a decolorizable toner was prepared in the same manner as in Example 1 except that 25 parts by weight of the dye composition particles Z were used, and the physical properties thereof were examined.

Table 3 shows the results of measuring the physical properties of the decolorizable toners obtained in Example 1 and Comparative Example 1.

[0155]

[Table 9]

From the results shown in Table 3, the decolorizable toner obtained in Example 1 is different from the decolorizable toner obtained in Comparative Example 1 in that different types of dyes are different dyes. It can be seen that since the dyes are dispersed in the composition particles, there is almost no interaction between dyes of different types, and the image stability, decoloring property, and color tone stability of the image are excellent.

[0157]

EFFECTS OF THE INVENTION In the decolorizable toner of the present invention, since different types of dyes are dispersed in separate dye composition particles, the domains are dispersed in the matrix containing the binder resin A as a main component. The dyes of different types are mixed, and the color tone of the decolorizable toner is not changed by the interaction, and the color tone of the image formed by using the decolorizable toner is hardly changed.

Further, when the domains constituting the decolorizable toner of the present invention have almost the same discoloration retention rate, an image formed by using the decolorizable toner is obtained. There is an effect that the color can be uniformly erased when the color is erased.

According to the method for producing a color erasable toner of the present invention, even when two or more kinds of dyes of different kinds are used in combination, there is almost no interaction between the dyes. An effect is obtained that toner can be obtained.

[Brief description of drawings]

FIG. 1 is a graph showing the change over time in the discoloration retention rate of dye composition particles X _{1 to} X ₃ according to the present invention.

FIG. 2 is a graph showing the change over time in the fading retention rate of the dye composition particles Y _{1 to} Y ₃ according to the present invention.

FIG. 3 is a graph showing the relationship between the light irradiation time and the decolorization rate of the dye composition particles X _{1 to} X ₃ according to the present invention.

FIG. 4 is a graph showing the relationship between the light irradiation time and the decolorization rate of the dye composition particles Y _{1 to} Y ₃ according to the present invention.

Front page continuation (72) Inventor Tsubasa Matsuba 3-2-15 Meiwadori, Hyogo-ku, Kobe-shi, Hyogo Bando Kagaku Co., Ltd. (72) Inventor Kiyotaka Yamaguchi 3-2-15, Meiwa-dori, Hyogo-ku, Hyogo Prefecture No. Bandou Kagaku Co., Ltd. (72) Inventor Takayuki Yoshida 3-2-15 Meiwatsu, Hyogo-ku, Kobe, Hyogo Prefecture Bando Kagaku Co., Ltd.

Claims (8)

[Claims] 1. A decolorizable toner comprising a matrix containing a binder resin A as a main component and a visible light to near infrared absorbing dye, a decolorizer and a domain containing a resin B as a main component, A decolorizable toner, wherein the domains are two or more domains in which at least the types of the dyes are different. 2. The decolorizable toner according to claim 1, wherein the domains have substantially the same fading retention rate and / or decolorization rate. 3. The decolorizable toner according to claim 1, wherein the binder resin A and the resin B are incompatible with each other. 4. A method for producing an erasable toner using particles of a dye composition containing a visible light to near infrared absorptive dye, a erasing agent and a resin B as main components, wherein at least the type of the dye is different. A method for producing an erasable toner, which comprises melting and kneading more than one kind of dye composition particles and a binder resin A under heating, cooling and pulverizing the resulting kneaded material to a predetermined particle size. 5. A method for producing an erasable toner using particles of a visible light to near-infrared absorptive dye, a erasing agent and a dye composition containing resin B as a main component, wherein at least the type of the dye is different. More than one type of dye composition particles and binder resin A
A method for producing an erasable toner, which comprises melt-kneading a toner particle containing as a main component with heat, cooling, and pulverizing the obtained kneaded product to a predetermined particle size. 6. The method for producing a decolorizable toner according to claim 4, wherein the dye composition particles have substantially the same discoloration retention rate and / or decolorization rate. 7. The dye composition particles have an average particle size of 5 to 50.
The method for producing a decolorizable toner according to claim 4, 5 or 6, having a particle size of 0 µm. 8. The method of producing a decolorizable toner according to claim 4, wherein the binder resin A and the resin B are incompatible with each other.