JP2762883B2 - Capsule toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcapsule toner used for developing an electric or magnetic latent image in electrophotography, electrostatic recording or magnetic recording.

[0002]

2. Description of the Related Art Heretofore, as one of electrophotographic toners for developing an electrostatic image formed on the surface of an electrophotographic photosensitive member, an electrostatic recording member, etc., it has been formed from a core material and an outer shell. Microcapsule toner is known, and various proposals have been made. Among these, Japanese Patent Application Laid-Open No. 57-179860
JP-A-58-21259, JP-A-58-66948, JP-A-59-148066, and JP-A-62-2227161 disclose a capsule toner technique using interfacial polymerization. Compared with other technologies, this technology has better sealing properties of the core material, wider flexibility of the core material, easier encapsulation, relatively better particle size distribution, outer shell modification Has many advantages such as easy control of toner chargeability. On the other hand, as the core substance,
JP-A Nos. 57-41647 and 57-185444 disclose waxes, and JP-A Nos. 58-145964 and 59-145.
JP-A-172654 discloses a mixture of an aliphatic ester polymer of acrylic acid or methacrylic acid and a high-boiling solvent, and JP-A-51-119231 and 59-159177 disclose soft resins having a long-chain alkyl group. ing.

However, it has been found that some problems arise when the above technique is applied to a color capsule toner for pressure fixing. That is, the capsule shell formed by interfacial polymerization generally has a high refractive index, and waxes, aliphatic ester polymers of acrylic acid or methacrylic acid, and soft resins having a long-chain alkyl group have a relatively low refractive index. Therefore, when such a substance having a low refractive index is contained in the core substance, the color and transparency of the copied image are remarkably reduced because the refractive index does not match that of the capsule shell. In particular, this is remarkable when an aromatic polymer is used for the capsule shell. Further, even if an interfacial polymer comprising an aliphatic monomer is used for the capsule shell, the shell material has a higher refractive index than the core material, and the above-mentioned disadvantages cannot be solved.

In order to increase the refractive index by using a monomer such as styrene as a core material in order to adjust the refractive index, the copolymerization ratio of styrene must be 50 wt% or more. As a result, there is a problem that the glass transition point Tg of the resin constituting the core material increases, the fluidity decreases, and the pressure fixing property decreases. On the other hand, there is a method in which a thickener such as oil is added to a resin having a high Tg to form a core substance, but in order to seal the oil in a capsule for a long time, a large amount of a capsule shell-forming monomer is used. The capsule shell needs to be thick. As a result, there is a problem that the capsule strength is increased and the pressure fixing property is reduced.

[0005]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems in the prior art, and its object is to make the refractive indices of the core material and the outer shell substantially coincide with each other. Excellent sealing properties of core material, easy encapsulation, excellent particle size distribution, easy control of toner chargeability by modification of outer shell, and good pressure fixability, suitable for color To provide an encapsulated toner.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies and as a result, have found that a polymer or copolymer containing an acrylic acid or methacrylic acid derivative having a benzene ring in an ester or amide component as a monomer component. It has been found that the above object can be attained by a capsule toner containing, in a shell, a core material (core) and a copolymer containing an aliphatic or alicyclic isocyanate as a shell-forming component. Thus, the present invention has been completed.

That is, the present invention provides a capsule toner comprising a core material and an outer shell covering the core material, wherein the core material comprises at least a polymer or a copolymer comprising a monomer component represented by the following general formula (I): An encapsulated toner containing coalesced coalescence and an outer shell containing a reaction product of an aliphatic or cycloaliphatic isocyanate.

Embedded image (Wherein, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents a hydrogen atom or an alkyl group, Y ₁ represents —O— or —NH—, and X represents —O— or —CH ₂ —. Show.
M is an integer of 0-8. As the copolymer contained in the core material, a copolymer comprising a monomer component represented by the above general formula (I) and a monomer component represented by the following general formula (II) is preferable.

CH ₂ ＣＲCR ₃ —CO—Y ₂ — (CH ₂ ) _n CH ₃ (II) (wherein R ₃ represents a hydrogen atom or a methyl group, and Y ₂ represents —O— or —NH— And n is an integer of 1 to 17.)

Hereinafter, the present invention will be described in detail. The core substance in the capsule toner of the present invention contains at least a polymer of the fixing component and a colorant, and preferably contains a high boiling solvent that dissolves or swells the polymer. Further, if necessary, a soft solid substance having a fixing property may be contained. The colorant can optionally replace the magnetic powder. As the core substance, additives such as silicone oil can be added for the purpose of further improving the fixing property. Further, an organic solvent mainly composed of an aliphatic saturated hydrocarbon which is insoluble in the polymer can be added. For the purpose of pressure fixing and for the purpose of heat fixing, it is desirable to change the thickness of the outer shell,
Further, the type of the fixing component or the composition ratio of the core substance component may be changed.

As the fixing polymer, a polymer or copolymer comprising a monomer component represented by the following general formula is used.

Embedded image (In the formula, R ₁ , R ₂ , Y ₁ , X and m are the same as described above.)

More specifically, benzyl acrylate, phenylethyl acrylate, β-tolylethyl acrylate, phenoxymethyl acrylate, phenoxyethyl acrylate, phenoxypropyl acrylate, N-phenylacrylamide, N-benzylacrylamide, N-benzylacrylamide Phenylethyl acrylamide, N-phenoxymethyl acrylamide, N-phenoxyethyl acrylamide, benzyl methacrylate, phenylethyl methacrylate, β-tolylethyl methacrylate, β- (ethylphenyl) ethyl methacrylate, phenoxymethyl methacrylate, phenoxyethyl methacrylate Phenoxypropyl methacrylate, N-phenylmethacrylamide, N-benzylmethacrylamide, N-phenylethylmethacrylamide, N- (β- Ruechiru) methacrylamide, N
-Phenoxymethyl methacrylamide, N-phenoxyethyl methacrylamide, N-phenoxypropyl methacrylamide and the like. Among these monomer components, polymers of benzyl acrylate, phenoxyethyl acrylate, benzyl methacrylate, and phenoxyethyl methacrylate are particularly preferably used.

Further, a copolymer of the monomer component represented by the general formula (I) and an acrylic acid or methacrylic acid derivative represented by the following general formula (II) has a refractive index and a capsule shell. It is further preferable in that it has the advantage of being easily matched. Where the capsule shell and (co)
The coincidence of the refractive indices of the polymers indicates that the difference in the refractive indices is within 0.05, preferably within 0.03.

Embedded image CH ₂ ＣＲCR ₃ —CO—Y ₂ — (CH ₂ ) _n CH ₃ (II) (wherein R ₃ , Y ₂ and n are the same as above)

Specifically, ethyl (meth) acrylate,
Propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate Alkyl esters of acrylic acid or methacrylic acid such as decyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, N-ethyl (meth) acrylamide, N-propyl (meth) acrylic acid Amide, N-butyl (meth) acrylamide,
Examples thereof include alkyl amides of acrylic acid or methacrylic acid such as N-hexyl (meth) acrylamide, N-decyl (meth) acrylamide, and N-stearyl (meth) acrylamide.

Examples of the colorant include inorganic pigments such as carbon black, red iron oxide, navy blue and titanium oxide; azo pigments such as fast yellow, disazo yellow, pyrazolone red, chelate red, brilliant carmine, and para brown; copper phthalocyanine; and metal-free phthalocyanine. Phthalocyanine pigments, condensed polycyclic pigments such as flavanthrone yellow, dibromoanthrone orange, perylene red, quinacridone red, and dioxazine violet. Further, disperse dyes, oil-soluble dyes and the like can also be used. Furthermore, in the case of a magnetic one-component toner or the like, all or part of the black colorant can be replaced with magnetic powder. As the magnetic powder, magnetite, ferrite, a simple metal such as cobalt, iron, nickel, or an alloy thereof can be used. In addition, these magnetic powders may be surface-treated with a coupling agent such as a silane coupling agent, a titanate coupling agent or an oil-soluble surfactant, or coated with an acrylic resin, a styrene resin, an epoxy resin, or the like. Magnetic powder may be used.

As the high boiling solvent that dissolves or swells the polymer, an oily solvent having a boiling point of 140 ° C. or higher, preferably 160 ° C. or higher can be used. For example, Moder
nPlastics Encyclopedia (19
75-1976), "Plasticizers". Further, as a core substance of a pressure fixing capsule toner, for example,
It may be selected from the high-boiling solvents disclosed in JP-A-145964 and JP-A-63-163373. Specifically, phthalic acid esters (diethyl phthalate, dibutyl phthalate, etc.), aliphatic dibasic acid esters (diethyl malonate, dimethyl succinate, dioctyl adipate, etc.), and phosphate esters (tricresyl phosphate, trixylate) Silyl phosphate, etc.), citrate esters (O-acetyltriethyl citrate, etc.), benzoic acid esters (butyl benzoate, hexyl benzoate, etc.), higher fatty acid esters (hexadecyl myristate, etc.), alkyl naphthalenes (methyl naphthalene) Dimethylnaphthalene, monoisopropylnaphthalene, diisopropylnaphthalene, etc.), alkyl diphenyl ethers (o-, m-, p-methyldiphenyl ether, etc.), higher fatty acid amides (N, N-dimethyllaurinamide, etc.) , Aromatic sulfonamides (such as N-butylbenzenesulfonamide), trimellitates (such as trioctyl trimellitate), and diarylalkanes (such as diarylmethane such as xylylphenylmethane and 1-phenyl-1-) Tolylethane, 1-xylyl-
Diarylethane such as 1-phenylethane and 1-ethylphenyl-1-phenylethane), and chlorinated paraffins.

When an aliphatic saturated hydrocarbon insoluble in a polymer or an organic solvent containing the same as a main component is used together with a high boiling point solvent, not only the fixability is improved but also the polymer is contained in the core substance. Good dispersion can be maintained. In particular, when a polymer having a long-chain alkyl group such as lauryl methacrylate homopolymer or copolymer is used as the polymer, it is desirable to use an aliphatic saturated hydrocarbon in combination. Such an aliphatic saturated hydrocarbon has a boiling point of 1
Those having a temperature of from 00 to 250 ° C. are preferable. For example, Isopar G and Isopar H manufactured by Exxon Chemical Co., Ltd.
Isopar L and the like. The soft solid substance is not particularly limited as long as it has flexibility at room temperature and has a fixing property, but a polymer substance having a Tg in a range of -60 to 5 ° C or a polymer substance thereof and another polymer substance Is preferably used.

The reaction product of the aliphatic or alicyclic isocyanate in the capsule toner of the present invention includes an isocyanate having no aromatic skeleton, which is a first outer shell forming component, and a second outer shell forming component. And a polyurea or polyurethane obtained by reacting with a compound having active hydrogen. Specific examples of isocyanates include hexamethylene diisocyanate, heptamethylene diisocyanate, 2,2-dimethylpentane-1,5-diisocyanate, octamethylene diisocyanate, trimethylhexane diisocyanate, and caproic acid. Aliphatic isocyanates such as -2,6-diisocyanate;
Bis- (isocyanatomethyl) tetrahydrofuran,
Heterocyclic aliphatic isocyanates such as oxy-5,5'-bis-furfuryl isocyanate, 1-methylcyclohexane-2,4-diisocyanate, 1-methylcyclohexane-2,6-diisocyanate, o-, m- or p-hexahydroxylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane
4,4'-diisocyanate, β, β-dicyclohexylpropane-4,4'-diisocyanate, bis- (2
-Methylcyclohexyl) methane-4,4'-diisocyanate, alicyclic isocyanates such as 1,3-bis- (α-isocyanatoethyl) cyclohexane, or synthesized using these isocyanates. Examples include polyisocyanates known as so-called burette type, adduct type, and isocyanurate type. These isocyanates can be used alone or as a mixture.

Specific examples of the compound having active hydrogen include 1,3-diaminopropane, 1,4-diaminobutane, 1,6-hexanediamine, 2-methylpentanediamine, diethylenetriamine, bis- (3-aminopropyl ) Amine, N, N-bis- (3-aminopropyl) methylamine, tris- (2-aminoethyl) amine, 1,2-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis- (amino Methyl) cyclohexane, piperazine, 2-methylpiperazine,
Examples thereof include polyamines such as 2,5-dimethylpiperazine, N-aminoethylpiperazine, and 1,4-bis- (3-aminopropyl) piperazine. Also, Jeffamine D-230, D-400, T-Texaco, a water-soluble prepolymer manufactured by Texaco Chemical Co., Ltd.
Polyoxyalkyleneamines such as -403 and water can also be used. These can be used alone or in combination.

Further, specific examples of the compound having active hydrogen include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol,
Diols such as 1,4-butanediol and polyoxyalkylene glycol, trimethylolethane, trimethylolpropane, hexanetriol, triols such as glycerin, polyols such as hexaols such as sorbitol, polyols obtained by hydrogenation of polyketones, poly Thioether polythiol, a polyester comprising these polyol compounds and oxalic acid, succinic acid, glutaric acid, dicarboxylic acid such as adipic acid,
Alternatively, a polyesteramide containing a dicarboxylic acid and a diamine or an amino alcohol as constituent components may be used. These can be used alone or in combination.

The method for producing the encapsulated toner of the present invention can utilize various known microencapsulation techniques. Among known methods, a microencapsulation method by an interfacial polymerization method and an internal in-situ polymerization method is preferable. The microencapsulation method by the interfacial polymerization method is described in, for example, JP-B-38-19574 and JP-B-42-446,
JP-B-2-31381, JP-A-58-66948
Nos. 59-148066 and 59-162562. That is, the isocyanates of the first shell forming component present in the oil droplets and the compound having active hydrogen of the second shell forming component present in the aqueous medium polymerize at the interface of the oil droplets. In addition, it is a method of forming a capsule shell by coating a core substance. In this polymerization method, the above-mentioned polyamines, polyoxyalkyleneamines, water and the like are used as the second shell forming component.

A microencapsulation method by an internal in-situ polymerization method is described in, for example, JP-B-49-45133,
No. 50-22507. That is, the isocyanates of the first outer shell-forming component and the compound having active hydrogen of the second outer shell-forming component present in the oily droplet form an internal and / or interface of the oily droplet containing the core substance. This is a method of polymerizing and coating a core substance to form a capsule shell. In this polymerization method, the above-mentioned polyol, polyester, polyesteramide and the like are used as the second shell forming component. In addition, the interfacial polymerization type encapsulation method and the in-situ polymerization type encapsulation method,
Both can be used together. The capsule shell obtained by these methods contains a polyurea or polyurethane structure, or a structure having a bond between both, as a component thereof, depending on the type of the second shell forming component.

In the production of the capsule toner of the present invention,
When the viscosity of the lipophilic core substance is high, the solvent is added to a low-boiling solvent in advance, the core substance component is suspended in an aqueous medium, and the solvent is added to the system simultaneously with or after the formation of the shell substance. Preferably, it is driven out to form a core material. Of course, the low boiling point solvent may be removed before capsule formation. As the low boiling point solvent, a solvent having a boiling point of 160 ° C. or lower is preferable.Specifically, methylene chloride, chloroform, carbon tetrachloride, ethylene chloride, carbon disulfide, methyl acetate, ethyl acetate, methyl alcohol, ethyl alcohol, Examples thereof include ethyl ether, tetrahydrofuran, dioxane, n-pentane, n-hexane, benzene, toluene, xylene, petroleum ether, acetone, methyl ethyl ketone, cyclohexanone, and dimethylformamide. These solvents can be used alone or as a mixture.

In the microencapsulation method described above, the polymer as one component of the core material is charged in advance in the form of a polymer together with other core material components, a shell-forming component, and optionally a low-boiling solvent, and is subjected to interfacial polymerization. A capsule shell can be formed and contained within the capsule. In addition, the monomer represented by the general formula (I) or the monomer represented by the general formulas (I) and (II) is charged as it is,
After forming the capsule shell by interfacial polymerization, the monomer can be polymerized to form a polymer or copolymer. On the other hand, the colorant or the magnetic powder charged as one component of the core material is usually present in the shell material after the capsule is formed, but may be present at the interface between the core material and the shell material.

The capsule toner of the present invention may be used to further improve the chargeability, powder fluidity, lubricity, etc., of metal, metal oxides such as titanium oxide and alumina, metal salts, inorganic substances such as silica and ceramics. And an external additive such as a resin such as polymethyl methacrylate and a metal salt of a fatty acid. Further, in order to impart chargeability, a method of forming a charge control polymer by a graft polymerization method on a capsule shell formed in advance using an interfacial polymerization method (Japanese Patent Application Laid-Open No. 62-22716).
Nos. 1 and 62-227162). Further, it may be a one-component capsule toner using no carrier, or a two-component capsule toner using a carrier. When a carrier is used, it is not particularly limited as long as it is a known carrier, and an iron powder-based carrier, a ferrite-based carrier, a surface-coated ferrite carrier, a magnetic powder-dispersed carrier, or the like can be used.

The capsule toner of the present invention is not limited to pressure fixing, and may be used for fixing by applying heat and pressure simultaneously.
Furthermore, in an image recording apparatus provided with a pressing member that comes into contact with the image carrier via a recording sheet or a pressing member having a heating unit inside, an image recording method in which toner is transferred and fixed simultaneously may be used. It is also effective when used for heat fixing. Further, it can be used not only for recording on paper, but also for a second original drawing, a sheet for an overhead projector (OHP), and the like.

[0025]

Next, the present invention will be specifically described with reference to examples and comparative examples. In the following, "parts" means parts by weight. Example 1 Benzyl methacrylate / lauryl methacrylate (45:55 wt%) copolymer 50 having a weight average molecular weight Mw of 30,000
Parts, Mw: 40,000 dimethylaminoethyl methacrylate /
Lauryl methacrylate (60:40 wt%) copolymer 1
Two parts, 6 parts of a magenta pigment (Carmine 6B) and 130 parts of ethyl acetate were mixed and dispersed by a sand mill for 3 hours. Further, 132 parts of the above-mentioned benzyl methacrylate / lauryl methacrylate copolymer was added to obtain a solution of the core substance in ethyl acetate. Next, 20 parts of an aliphatic polyisocyanate (Takenate D160N; manufactured by Takeda Pharmaceutical Co., Ltd.) is added and mixed well, and then a 4% aqueous solution 3 of propoxymethylcellulose (Metroze 65SH50; manufactured by Shin-Etsu Chemical Co., Ltd.) is added.
Disperser (Homodisper; manufactured by Tokushu Kako Co., Ltd.) in 00 parts
Was dispersed and emulsified using the above method. The dispersion was switched to stirring by a stirrer (Three One Motor; manufactured by Shinto Kagaku),
Into this, 50 parts of a 5% aqueous solution of diethylenetriamine was dropped. Thereafter, the mixture was heated to 60 ° C. to carry out an encapsulation reaction for 3 hours while driving out ethyl acetate. After completion of the reaction, the capsule toner was separated by centrifugation, and then redispersed by adding 1 liter of ion-exchanged water. The capsule toner was separated again by centrifugation to wash the capsule. Repeat this operation 10 more times.
This was repeated and freeze-dried to obtain a capsule toner.
The average particle size of this toner was 10 μm. The obtained capsule toner was sandwiched between OHP sheets, and was fixed on the OHP sheets under a pressure of 400 kg / cm ^{2 by} a pressure fixing device. When the fixed image was projected on the screen by the OHP, a magenta projected image was obtained.

Comparative Example 1 A capsule toner was prepared in exactly the same manner as in Example 1 except that the aliphatic polyisocyanate (Takenate D160N) was replaced with an aromatic polyisocyanate (Sumidur L-75; manufactured by Sumitomo Bayer Urethane Co., Ltd.). I got As in Example 1, the obtained capsule toner is sandwiched between OHP sheets,
The sheet was fixed on an OHP sheet under a pressure of 400 kg / cm ^{2 by} a pressure fixing device. When the fixed image was projected on the screen with the OHP, the amount of light reaching the screen was small, and the projected image became gray and turbid.

Example 2 Except that the benzyl methacrylate / lauryl methacrylate copolymer was replaced by a copolymer of Mw: 30,000 phenoxyethyl methacrylate / lauryl methacrylate (50:50 wt%), which was completely the same as in Example 1. An encapsulation reaction was performed in the same manner. After the reaction, the capsules are separated by centrifugation.
1 l of deionized water was added to redisperse. The capsule was again separated by centrifugation to wash the capsule toner. After this operation was further repeated 10 times, a capsule dispersion having a solid content of 20% was obtained. 250 parts of this dispersion is put into a reactor equipped with a stirrer, 5 parts of a 1N aqueous nitric acid solution, 0.5 parts of cerium ammonium nitrate and 0.5 parts of ethylene glycol dimethacrylate are sequentially added into the reactor and reacted for 2 hours. Was. After the completion of the reaction, the mixture was washed with water by centrifugation to obtain a capsule dispersion having a solid content of 20% again. Next, 0.5 part of potassium persulfate, 1 part of methyl methacrylate, 0.5 part of dimethylaminoethyl methacrylate and 0.2 part of sodium bisulfite were sequentially added and reacted for 2 hours. After the completion of the reaction, the resultant was washed with water by centrifugation, and freeze-dried under vacuum to obtain a capsule toner having a charge control polymer graft-polymerized on the surface.

Copy machine (Fuji Xerox 2700) obtained by modifying the obtained capsule toner for pressure fixing test
To form a copy image on plain paper. When the image was fixed with a pressure fixing device under a pressure of 400 kg / cm ² , the image did not deteriorate even when rubbed with a finger, and the fixability was good. Next, when a fixed image sandwiched between OHP sheets was formed and projected on a screen in the same manner as in Example 1, a magenta color projected image was obtained.

Comparative Example 2 The procedure was the same as in Example 2 except that the phenoxyethyl methacrylate / lauryl methacrylate copolymer was replaced by a styrene / lauryl methacrylate (50:50 wt%) copolymer having an Mw of 30,000. Thus, a capsule toner was obtained. Example 1
In the same manner as described above, the obtained capsule toner is sandwiched between OHP sheets, and O ² is pressed with a pressure fixing device under a pressure of 400 kg / cm ^2.
Fixed on HP sheet. When the fixed image was projected on the screen by the OHP, a magenta projected image was obtained. However, when the capsule toner was fixed on plain paper and rubbed with a finger in the same manner as in Example 2, the image was peeled off, resulting in poor fixability.

[0030]

The capsule toner of the present invention contains a polymer or copolymer having a monomer component of an acrylic acid or methacrylic acid derivative having a benzene ring in an ester or amide component as a core material, and comprises polyurea or polyurethane. Is contained in the outer shell, so that the refractive indices of the core material and the outer shell can be substantially matched. In addition, the present invention has excellent sealing properties of the core material, easy encapsulation, excellent particle size distribution, easy control of toner chargeability by modifying the outer shell, and good pressure fixability. Thus, a capsule toner suitable for a color can be provided.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 9/08 311 CA (STN)

Claims (2)

(57) [Claims] 1. A capsule toner comprising a core material and an outer shell covering the core material, wherein the core material contains at least a polymer or copolymer comprising a monomer component represented by the following general formula (I). And an outer shell containing a reaction product of an aliphatic or alicyclic isocyanate. Embedded image (Wherein, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents a hydrogen atom or an alkyl group, Y ₁ represents —O— or —NH—, and X represents —O— or —CH ₂ —. Show.
M is an integer of 0-8. ) 2. The copolymer contained in the core substance comprises a monomer component represented by the general formula (I) and a monomer component represented by the following general formula (II). The capsule toner according to the above. CH ₂ ＣＲCR ₃ —CO—Y ₂ — (CH ₂ ) _n CH ₃ (II) (wherein R ₃ represents a hydrogen atom or a methyl group, and Y ₂ represents —O— or —NH— And n is an integer of 1 to 17.)