JPH07120963A - Microcapsule toner and its production - Google Patents

Abstract

PURPOSE:To provide a microcapsule toner which has good fixation properties and with which the offset phenemenon hardly occurs and a sharp image can be obtained and also to provide a method for production of the toner. CONSTITUTION:This microcapsule toner contains as the core material, a binder resin, a paraffinic oil and a polyester compound which has an acid value of 15 to 40 and is soluble in the paraffinic oil and as the shell material, polyurea or polyurethane. Also the toner contains a colorant in the core material and/or shell material. As the polyester compound, that not having any carboxylate within its molecule is preferred. The capsule toner can also be produced by mixing this polyester compound with the other constituent materials of the core material, further mixing the resulting mixture with a polyisocyanate, dispersing and emulsifying the mixture thus obtained in an aqueous medium and encapsulating the resulting emulsified liquid drops through polymerizing the latter mixture with a polyhydroxyl compound or polyamine at the interfaces of the liquid drops.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner, especially a microcapsule toner, for developing an electrostatic latent image in electrophotography, electrostatic printing and the like.

[0002]

2. Description of the Related Art Various proposals have been made for a microcapsule toner comprising a core substance and a capsule shell covering the core substance. Among them, as a core substance, JP-A-54
-66844, 55-18630, and 5
Nos. 7-41647 and 57-202547 disclose wax compounds, and JP-A-52-108134, 58-9153, 59-159174 and 59-159177 disclose wax compounds. Soft polymer,
JP-A-56-119137 and JP-A-58-14596.
No. 4 and No. 63-163373 disclose microcapsule toners containing a polymer solution as a fixing component of a core substance.

[0003]

However, when a wax-based compound is used as the fixing component of the core substance, there is a drawback that the fixing property is poor. When a soft polymer or a polymer solution is used as the fixing component of the core substance, the fixing property is good, but at the time of fixing, a part of the toner in the image area is transferred to the fixing roll, a so-called offset phenomenon occurs, and However, there is a drawback that problems such as deterioration and image transfer to the non-image area occur. This is a problem especially when paraffin oil and a binder resin that dissolves in the paraffin oil are used as the core substance. Therefore, the present invention is
The present invention has been made in order to solve the above-mentioned drawbacks in the prior art, and its purpose is to provide a microcapsule toner having good fixability, less likely to cause an offset phenomenon, and capable of obtaining a clear image, and its production. To provide a method.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to improve the fixability of microcapsule toners, and as a core substance component, a polyester compound having an acid value within a specific range is contained. As a result, they have found that the above object can be achieved, and completed the present invention. That is, in the microcapsule toner of the present invention, the core substance is composed of at least a paraffinic oil, a polyester compound soluble in the oil and a binder resin, and the shell substance is composed of at least polyurea or polyurethane. The substance contains a coloring material, and the polyester compound has an acid value of 15 to 40. The method for producing a microcapsule toner of the present invention has an acid value of 15 to 4
At 0, a polyester compound soluble in paraffinic oil is mixed with another core material constituent material, an isocyanate compound is mixed with the core material constituent material mixture, and the mixture is dispersed and emulsified in an aqueous medium to obtain a liquid. It is characterized by comprising a step of polymerizing at a droplet interface and encapsulating.

The present invention will be described in detail below. The microcapsule toner of the present invention uses a paraffinic oil, a polyester compound and a binder resin as the core substance constituent material, and the shell substance coating the core substance is
It is composed of polyurea or polyurethane, and contains a coloring material containing one or both of a core substance and a shell substance, and these are essential components. As the paraffin oil, the main component is normal paraffin or isoparaffin, and the boiling point is 140 ° C. or higher, preferably 1
An oily solvent having a temperature of 60 ° C. or higher can be used, and it is preferable to dissolve the binder resin. For example, Isopar H, Isopar L manufactured by Exxon Chemical Co.,
Isopar M and NA solvent manufactured by NOF CORPORATION can be used.

The polyester compound has an acid value (KOHmg / g) of 15 when dissolved in the above paraffinic oil.
What is ˜40 is used. In addition, it is generally unavoidable that a plurality of carboxyl groups are introduced into the molecule of the polyester compound in production, but it is preferable that the polyester compound does not have a carboxylate salt from the viewpoint of charging property. Although the reason why it is preferable has not been sufficiently clarified, as described above, since the polyester compound has a plurality of carboxyl groups in the molecule, it reacts with the isocyanate charged as a capsule-forming monomer to cause intermolecular or intramolecular reaction. By forming a cross-linking structure with, to give the toner an appropriate cohesive force, as a result,
It is presumed that the effect that the offset phenomenon does not easily occur at the time of fixing is exhibited. The polyester compound is a polybasic acid such as adipic acid, sebacic acid, phthalic acid, fumaric acid, maleic anhydride, malonic acid, succinic acid, glutaric acid or trimellitic acid, and ethylene glycol, triethylene glycol, 1,2- Propylene glycol, 1,3-
It is a polymer obtained by polycondensation with a polyhydric hydroxy compound such as butanediol, 1,4-butanediol, neopentylene glycol and bisphenol A, and the molecular weight thereof may be in the range of 1,000 to 100,000. Specifically, Solsperse 3000, Solsperse 9000, Solsperse 17000 and the like manufactured by Zeneca Co., which are known as pigment dispersants, can be used.

As the binder resin, those which are soluble in paraffinic oil are preferable from the viewpoint of solubility and fixing property in paraffinic oil. Specifically, a copolymer containing at least a long-chain alkyl (meth) acrylate-based monomer component represented by the following general formula is preferable.

[Chemical 1] Here, R represents hydrogen or a methyl group, and n is 7 to 17
Means an integer of.

The monomers copolymerizable with the long-chain alkyl (meth) acrylate type monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic. 2-ethylhexyl acid,
Dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, trifluoroethyl (meth) acrylate, glycidyl (meth) acrylate,
Tetrahydrofurfuryl (meth) acrylate, (meth)
Acrylamide, N-methyl (meth) acrylamide,
N-ethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-phenyl (meth) acrylamide, N-benzyl (meth) acrylamide, N, N-
Acrylic and methacrylic acid monomers such as dimethyl (meth) acrylamide and (meth) acrylonitrile,
Styrene-based monomers such as styrene, methylstyrene, chloromethylstyrene, formylstyrene, hydroxystyrene, vinylbenzoic acid ester, styrenesulfonic acid, its sodium salt, styrenesulfonic acid ester, alkoxystyrene, divinylbenzene, vinyl formate, acetic acid. Vinyl, vinyl chloroacetate, vinyl trifluoroacetate,
Vinyl esters such as vinyl propionate, vinyl pivalate, vinyl laurate, and vinyl stearate, vinyl ether monomers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, 2-ethylhexyl vinyl ether, methoxyethyl vinyl ether, and diethylene glycol divinyl ether. Vinylcarbonyl monomers such as methyl vinyl ketone, methyl isopropenyl ketone, benzylideneacetone, benzylideneacetophenone, diisopropylideneacetone, cyclopenten-3-one, acrolein, methacrolein, crotonaldehyde, cinnamaldehyde, maleic anhydride, malein Acid esters, maleamic acid, maleimide and substituted maleic acid derivatives, vinylpyrrolidone, vinylpyrrolidone Emissions, vinylimidazole, 1-vinyl-2-methylimidazole, vinyl carbazole, N
-Nitrogen-containing vinyl monomers such as vinylcaprolactam and N-vinylphthalimide are mentioned. Among these, a (meth) acrylic acid ester-based monomer and a styrene-based monomer different from the (meth) acrylic acid long-chain alkyl ester are particularly preferable. The copolymerization ratio is such that the long-chain alkyl (meth) acrylate-based monomer has a molar ratio of 10% or more, preferably 2
It is 0% or more.

Examples of the coloring material include inorganic pigments such as carbon black, red iron oxide, dark 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. And condensed polycyclic pigments such as flavantron yellow, dibromoanthrone orange, perylene red, quinacridone red, and dioxazine violet. Further, disperse dyes, oil-soluble dyes and the like can also be used. Further, as the magnetic one-component toner, all or part of the black color material can be replaced with magnetic powder. As magnetic powder, magnetite, ferrite, cobalt,
Simple metals such as iron and nickel and their alloys can be used. Further, these magnetic powders may be surface-treated with a coupling agent such as a silane coupling agent or a titanate coupling agent or an oil-soluble surfactant, or the surface may be coated with an acrylic resin, a styrene resin or an epoxy resin. May be. The coloring material or magnetic powder charged as one component of the core substance may be present at the interface between the core and the outer shell or in the outer shell after encapsulation described later.

If necessary, silicone oil may be added as a core material-constituting material for the purpose of improving the fixability, and additives such as oil-soluble surfactants may be added for improving the dispersion of the coloring material. Further, a high boiling point solvent which does not dissolve the binder resin can be added to the high boiling point solvent which dissolves the binder resin.

In the encapsulation method of the present invention, the internal in
It is preferable to use an in situ polymerization method or an interfacial polymerization method. The capsule shell obtained by these methods is
Generally composed of polyurea or polyurethane. The encapsulation method by the internal in-situ polymerization method is
For example, Japanese Patent Publication No. 49-45133 and 50-225.
As disclosed in Japanese Patent Application Laid-Open No. 07-2007, the first capsule shell-forming monomer and the second capsule shell-forming monomer present in the oily droplet react at the inside and / or the interface of the oily droplet. It is a method of forming a capsule shell. Further, the encapsulation method by the interfacial polymerization method is disclosed in, for example, Japanese Patent Publication No. 38-1957.
4, gazette 42-446 gazette, Japanese Patent Publication No. 2-3138
No. 1, JP-A-58-66948, and JP-A-59-1.
As disclosed in JP-A-48066 and JP-A-59-162562, a first capsule shell forming monomer present in a solvent and a second capsule shell forming monomer present in an oily droplet Is a method of reacting at the interface of oily droplets to form a capsule shell. That is, the preferred method for producing a microcapsule toner in the present invention has an acid value of 15 to 40.
The above polyester compound soluble in paraffinic oil is mixed with another core material constituent material, the core material mixture is mixed with an isocyanate compound which is a first capsule shell forming monomer, and the resulting mixture is mixed in an aqueous medium. Dispersed and emulsified, and polymerized at the droplet interface to encapsulate.

The first capsule shell forming monomer is m
-Phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, 3,3'-
Dimethyldiphenyl-4,4'-diisocyanate,
Diisocyanates such as 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, xylylene diisocyanate, naphthalene diisocyanate and hexamethylene diisocyanate, as well as polyisocyanates known as so-called buret type, adduct type and isocyanurate type are used. Preference is given to using. For example, polyisocyanates that are commercially available as Sumidure series manufactured by Sumitomo Bayer Urethane Co., Takenate series manufactured by Takeda Pharmaceutical Co., Ltd., and Millionate series manufactured by Nippon Polyurethane Industry Co., Ltd. are preferably used.

When the internal in-situ polymerization method is used, it is necessary to mix the second capsule shell forming monomer with the first capsule shell forming monomer in the core material mixture. The second capsule shell forming monomer is a compound that reacts with the first capsule shell forming monomer to form a polymer. Specifically, ethylene glycol, 1,4-butanediol, catechol, resorcinol, hydroquinone, o-dihydroxymethylbenzene, 4,4′-
Examples thereof include polyhydroxy compounds such as dihydroxydiphenylmethane and 2,2-bis (4-hydroxyphenyl) propane. On the other hand, when the encapsulation method by interfacial polymerization is used, it is preferable to mix the second capsule shell-forming monomer in the aqueous medium. As the second capsule shell-forming monomer, other than the above polyhydroxy compound, ethylenediamine, tetramethylenediamine, hexamethylenediamine, phenylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylethylenediamine, etc. Examples of the polyamine, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine and other piperazine compounds, and water.

In the method for producing the microcapsule toner, the method of incorporating the binder resin into the core substance in the capsule is to prepare the polymer in advance in the form of a polymer together with other core substance constituent materials, a low boiling point solvent and a shell-forming component, At the same time when the outer shell is formed by interfacial polymerization or after the outer shell is formed, a method of expelling the low boiling point solvent out of the system to form a core substance,
After forming the outer shell by charging interfacial polymerization in the monomer state,
Either method of polymerizing the monomer to form the core substance may be used. Further, an external additive such as silicon oxide, aluminum oxide, titanium oxide or carbon black may be added to the capsule toner in order to impart fluidity or chargeability. The external additive may be added by drying the capsule toner and then adhering it to the toner surface using a mixer such as a V blender or a Henschel mixer, or dispersing the external additive in water or an aqueous solvent such as water / alcohol. A method of adding the external additive to the surface of the toner by adding it to the capsule toner in a slurry state and then drying it after the treatment is performed.

[0015]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Example 1 (Preparation of capsule particles) A lauryl methacrylate-styrene copolymer (Mw = 4 × 1) was added to a mixed solution of 40 g of Isopar H (manufactured by Exxon Chemical Co., Ltd.) and 40 g of ethyl acetate.
0 ⁴ ) 60 g and 1.2 g of a polyester compound (Solsperse 3000: manufactured by Zeneca) having an acid value of 30 to 35 were added and dissolved. To this, 80 g of magnetic powder (EPT-1000: manufactured by Toda Kogyo Co., Ltd.) was added and dispersed by a sand mill for 3 hours. Then, to 100 g of this dispersion, 30 g of polyisocyanate (Sumijour L: manufactured by Sumitomo Bayer Urethane Co., Ltd.) and 10 g of ethyl acetate were added and thoroughly mixed (this liquid is referred to as liquid A). On the other hand, ion-exchanged water 20
Dissolve 10 g of hydroxypropylmethyl cellulose (Metroses 65SH50: manufactured by Shin-Etsu Chemical Co., Ltd.) in 0 g, and
It was cooled to 0 ° C. (this liquid is called liquid B). Then, the liquid B was stirred with an emulsifying machine (auto homomixer: manufactured by Tokushu Kika Kogyo Co., Ltd.), and the liquid A was slowly added into the liquid for emulsification.
Thus, the average particle size of the oil droplet particles in the emulsion is about 1
A 2 μm O / W emulsion was obtained. Next, the emulsifier was changed to a stirrer equipped with a propeller-type stirrer (Three One Motor: manufactured by Shinto Kagaku Co., Ltd.) and stirred at 400 rpm. After 10 minutes, 100 g of a 2.5% aqueous solution of diethylenetriamine as the second capsule shell forming monomer was added dropwise thereto. After the dropping was completed, the encapsulation reaction was carried out for 3 hours while removing ethyl acetate at 60 ° C. 2 after the reaction
It was poured into 1 liter of ion-exchanged water, sufficiently stirred and allowed to stand.
After the capsule particles settled, the supernatant was removed. This operation was repeated 7 times to wash the capsule particles.

(Tonerization) 125 g of a suspension of capsule particles (corresponding to 50 g of capsule particles) having a solid content concentration of 40% by adding ion-exchanged water to 1 g of a separ equipped with a cooling pipe and a nitrogen introducing pipe. Put it in a bull flask,
Ion-exchanged water (125 g) was added, and the mixture was stirred at 200 rpm with a stirrer (Three One Motor) under a nitrogen atmosphere. Diethylaminoethyl methacrylate 1.0
g, 2.0 g of methyl methacrylate and 1.6 g of potassium persulfate were added. Next, 0.15 g of sodium hydrogen sulfite was added and the reaction was carried out at 20 ° C. for 1 hour to deposit the charge control polymer on the capsule surface. After the reaction,
It was poured into 2 liters of ion-exchanged water, sufficiently stirred and allowed to stand. After the capsule particles settled, the supernatant was removed.
This operation was repeated 4 more times to wash the capsule particles. The obtained capsule suspension was opened in a stainless steel vat, dried for 10 hours at 60 ° C with a dryer (manufactured by Yamato Scientific Co., Ltd.), passed through a 100 mesh sieve, and then further dried with a dryer.
Heat treatment at 0 ° C for 24 hours, sieving on 325 mesh sieve,
The microcapsule toner of the present invention was obtained.

Next, with respect to 100 parts by weight of this toner, carbon black (REGAL330R: manufactured by Cabot) is used.
Was added in an amount of 0.1 part by weight and mixed well, and then the copier (270
(0: manufactured by Fuji Xerox Co., Ltd.) was modified for capsule toner and the pressure fixing device shown in FIG. 1 was used to perform fixing evaluation with a fixing load of 5884 N (600 kgf). As a result, no offset was observed and a clear image could be obtained. The pressure fixing device is as follows. That is, the fixing roller 1 is rotatably supported, and the pressure roller 2 intersects with the rotation axis of the fixing roller 1 (intersection angle 1.
61) and is rotatably and swingably supported, and pressing force is applied between both rollers by a pressure device (not shown). Here, while the guide member 5 regulates the feeding direction of the image support 4 such as a sheet on which the toner image 3 is transferred,
The toner image 3 is pressure-fixed on the image support 4 by bringing the fixing roller 1 and the pressure roller 2 into pressure contact with each other. The fixing roller 1 and the pressure roller 2 are provided with peeling claws 6 and 7 respectively so as not to wind the image support 4 through the image support 4, and on the surface of the fixing roller 1. A cleaning member 8 for scraping the toner when a part of the toner image 3 adheres to the fixing roller 1 is installed. The fixing roller 1 and the pressure roller 2 are hard chrome plated on the surface of hardened steel, the fixing roller 1 and the pressure roller 2 have the same size, and the effective length of the roller is 270 mm and the outer diameter is It is 35 mm.

Comparative Example 1 Capsule toner was obtained by the same procedure as in Example 1 except that the polyester compound was not added. The obtained capsule toner was evaluated in exactly the same manner as in Example 1. As a result, offset was generated, and only an image in which sharpness due to image stain was remarkably inferior was obtained.

Example 2 (Preparation of Capsule Particles) 2.4 g of a polyester compound having an acid value of 18 to 23 (Solsperse 3000: manufactured by Zeneca) was dissolved in 40 g of Isopar M (manufactured by Exxon Chemical Co.), and lauryl methacrylate- Styrene copolymer (M
w = 3 × 10 ⁴ ) 30 g, lauryl methacrylate-butyl methacrylate copolymer (Mw = 3 × 10 ⁴ ) 30 g
And 50 g of ethyl acetate were added and dissolved. To this, 80 g of magnetic powder (the above EPT-1000) was added and dispersed in a sand mill for 3 hours. Then 100 g of this dispersion
Against polyisocyanate (Takenate D110N:
Takeda Pharmaceutical Co., Ltd.) 40 g and ethyl acetate 20 g,
The mixture was thoroughly mixed (this liquid is referred to as liquid A). On the other hand, 10 g of hydroxypropylmethyl cellulose (Metroze 65SH50) and 0.3 g of diethylenetriamine were dissolved in 200 g of ion-exchanged water and cooled to 5 ° C. (this liquid is referred to as liquid B). After that, the solution B was stirred with an emulsifying machine (the above auto homomixer), and the solution A was slowly charged into the solution to emulsify the solution. In this way, an O / W emulsion in which the average particle size of the oil droplet particles in the emulsion was about 12 μm was obtained. Next, the emulsifier was changed to a stirrer (the above three-one motor), and stirring was performed at 400 rpm. After 10 minutes, 100 g of a 2.5% aqueous solution of diethylenetriamine as the second capsule shell forming monomer was added dropwise thereto. After completion of the dropping, the encapsulation reaction and the crosslinking reaction of the vinyl polymer were carried out for 5 hours while removing ethyl acetate at 60 ° C. After completion of the reaction, the reaction mixture was poured into 2 liters of ion-exchanged water, sufficiently stirred and allowed to stand. After the capsule particles settled, the supernatant was removed. This operation was repeated 7 times to wash the capsule particles.

(Toner-ized) 125 g of a suspension of capsule particles (corresponding to 50 g of capsule particles) with ion-exchanged water added to the capsule particles to give a solid content concentration of 40% was prepared as a 1 l separa equipped with a cooling pipe and a nitrogen introducing pipe. Put it in a bull flask,
Ion-exchanged water (125 g) was added, and the mixture was stirred at 200 rpm with a stirrer (Three One Motor) under a nitrogen atmosphere. 0.2g of ethyltrimethylammonium methacrylate chloride, 2.0g of methyl methacrylate
And 1.6 g of potassium persulfate were added. Then, 0.15 g of sodium hydrogen sulfite was added and the reaction was carried out at 20 ° C. for 2 hours. After the completion of the reaction, 10 g of a 5% sodium naphtholsulfonate aqueous solution was added to exchange chlorine ions with naphtholsulfonate ions. In this way, the charge control polymer was attached to the capsule surface. After ion exchange, the mixture was poured into 2 liters of ion exchange water, sufficiently stirred and allowed to stand. After the capsule particles settled, the supernatant was removed. This operation was repeated 4 more times to wash the capsule particles. The obtained capsule suspension was placed in a stainless steel vat and dried at 60 ° C. for 10 hours with a drier to obtain 10
After sieving through a 0 mesh sieve, it is further dried in a dryer at 60 ° C for 24 hours.
It was heat-treated for an hour and passed through a 325 mesh sieve to obtain a microcapsule toner of the present invention.

Next, 1 part by weight of hydrophobic silica (RA200H: manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of this toner, and after sufficiently mixing, in an environment of a temperature of 20 ° C. and a humidity of 50%. The fixing evaluation was performed in the same manner as in Example 1. As a result, no offset was observed and a clear image could be obtained.

Comparative Example 2 Except that the polyester compound was replaced with a polyester compound having an acid value of 6 to 8 (Solsperse 13940: manufactured by Zeneca), the same treatment as in Example 2 was carried out, but poor emulsification occurred and satisfactory results were obtained. No capsule was obtained.

[0023]

As described above, the microcapsule toner of the present invention contains, as a core substance, at least a paraffinic oil, a polyester compound having an acid value of 15 to 40 which dissolves in the oil, and a binder resin, and has a shell substance. Is composed of at least polyurea or polyurethane, which has a good fixing property and is less likely to cause an offset phenomenon, so that a clear image can be obtained.

[Brief description of drawings]

FIG. 1 shows a pressure fixing device used in a microcapsule toner fixing evaluation test.

[Explanation of symbols]

1 ... Fixing roll, 2 ... Pressure roll, 3 ... Toner image, 4 ...
Image support, 5 ... Guiding member, 6, 7 ... Peeling nail, 8 ... Cleaning member.

Claims (3)

[Claims] 1. A core material is composed of at least a paraffinic oil, a polyester compound soluble in the oil, and a binder resin, and a shell material is composed of at least polyurea or polyurethane, and a coloring material is added to the core material and / or the shell material. A microcapsule toner containing the polyester compound, wherein the polyester compound has an acid value of 15 to 40. 2. The microcapsule toner according to claim 1, wherein the polyester compound does not contain a carboxylate in the molecule. 3. A step of mixing a polyester compound having an acid value of 15 to 40 and soluble in paraffinic oil with another core material constituent material, a step of mixing an isocyanate compound to the core material constituent material mixture, and the mixture. A method for producing a microcapsule toner, which comprises a step of dispersing and emulsifying the above in an aqueous medium, and polymerizing at a droplet interface to encapsulate.