JP2000098662A - Electrostatic charge image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner having a low fixing temp., good transparency for an OHP and excellent storage property by suspension-polymerizing polymerizable monomers in the presence of a coloring agent and low mol.wt. ε-caprolactone polymer. SOLUTION: A capsule toner for heat-press fixing is prepared by suspension polymn. of polymerizable monomers in the presence of a coloring agent, release agent and ε-caprolactone polymer. The mol.wt. of ε-caprolactone ring-opened polymer is 3000 to 8000 as the number average mol.wt. The ring-opened ε- caprolactone polymer is obtd. by the reaction of ε-caprolactone and diols such as ethylene glycol and diethylene glycol in the presence of a catalyst. The obtd. toner consists of 90 to 99 wt.% of polymer component from the polymerizable monomers, preferably 91 to 98 wt.%, and 1 to 10 wt.% of ring- opened polymer component of lactone, preferably 2 to 9 wt.%. The polymer component forms the core, while the ring-opened lactone polymer forms the shell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a toner for developing an electrostatic image, and more particularly, to a toner for developing an electrostatic image formed by an electrophotographic method, an electrostatic recording method or the like.

[0002]

2. Description of the Related Art Conventionally, an electrostatic latent image formed in an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus is first developed with a developer made of a toner, and then the formed developer image is formed. Is transferred onto a transfer material such as paper as necessary, and then fixed by various methods such as heating and pressing. As a toner, generally, a colorant, a charge controlling agent, a release agent, and the like are melt-mixed and uniformly dispersed in a thermoplastic resin to form a composition, and then the composition is pulverized and classified. Or by dissolving or dispersing a colorant, a charge controlling agent, a release agent and the like in a polymerizable monomer, adding a polymerization initiator, and then heating to a polymerization temperature to carry out polymerization. Thereafter, each of the toners has been manufactured by a polymerization method of obtaining a toner by filtration, washing, dehydration, and drying.

Recently, power consumption has been reduced in electrophotographic copying machines, printers and the like using toner. In the electrophotographic method, a step that particularly consumes energy is a fixing step. Generally, a heat roll of 150 ° C. or higher is used for fixing, and electric power is used as an energy source. It is required to lower the temperature of the hot roll from the viewpoint of energy saving. For that purpose, it is necessary to lower the fixing temperature of the toner. In the design of the toner, in order to respond to the demand from the copying machine, it is sufficient to lower the glass transition temperature of the toner, but if the glass transition temperature is lowered, blocking occurs during storage of the toner or in the toner box. Agglomerates form a so-called poor storage stability toner.

On the other hand, in the case of electrophotographic color toners, OHPs for presentations at various conferences have recently been used.
In many cases, a color image is used for a sheet or the like, and it is required that color toners have excellent OHP transparency (transparency). In order to satisfy the OHP transparency, it is essential that the toner is uniformly melted on the OHP sheet. To this end, the melt viscosity near the fixing temperature of the toner is lower than that of the conventional one. It is necessary to design low. In order to lower the melt viscosity of the toner, there are methods such as lowering the molecular weight and lowering the glass transition temperature as compared with the conventional binder resin for toner.However, when any of the methods is adopted, blocking occurs. It is easy to use and has poor storage stability.

As described above, a decrease in the fixing temperature of the toner and
There is an inverse correlation between the technique for improving the HP permeability and the storage stability of the toner. However, a polymerized toner obtained by a conventional suspension polymerization method generally has insufficient fixability to an OHP sheet and OHP permeability. On the other hand, it is known that a toner made of polyester is excellent in fixability and transmittance to an OHP sheet. However, polyester is generally produced by a polycondensation method, and the suspension polymerization method cannot be applied. A toner made of polyester must be manufactured by a pulverization method, and has problems such as uneven shape, wide particle size distribution, and low yield.

Recently, in a capsule toner comprising a heat-fusible core material containing a thermoplastic resin and a colorant, and an outer shell provided so as to cover the surface of the core material, an amorphous polyester A heat and pressure fixing capsule toner used as a main component of a shell material has been proposed (JP-A-7-248).
644). This capsule toner is manufactured by suspension-polymerizing a vinyl monomer such as styrene or an acrylate ester in the presence of an amorphous polyester or a colorant. Therefore, the shape of the capsule toner is spherical and uniform as compared with the toner obtained by the pulverization method. In this encapsulated toner, the glass transition temperature of the thermoplastic resin, which is the main component of the heat-meltable core material, is set to 10 to 10.
While the fixing property is improved by lowering the temperature to 50 ° C., the glass transition temperature of the amorphous polyester, which is the main component of the outer shell material, is 50 to 8
The temperature is as high as 0 ° C. to provide anti-blocking properties. The above-mentioned publication describes that an amorphous polyester is used for the encapsulated toner because crystalline polyester requires a large energy for melting and has a high glass transition temperature. However, this capsule toner does not always have good low-temperature fixability and OHP fixability because the amorphous polyester of the outer shell material has a relatively high glass transition temperature. In addition, the amorphous polyester has insufficient blocking resistance as compared with the crystalline polyester.

First, we proposed a capsule toner for heat and pressure fixing using an ε-caprolactone polymer as a main component of an outer shell material in Japanese Patent Application Laid-Open No. 9-269610.
This capsule toner is manufactured by suspension polymerization of a vinyl monomer such as styrene or an acrylate in the presence of an ε-caprolactone polymer or a colorant. The toner thus obtained has good transparency to OHP and excellent storage stability.
Further, the melting point of the ε-caprolactone polymer used in this example was 60 ° C., and the fixing property to OHP was excellent. In this publication, it is described that the number average molecular weight of the ε-caprolactone polymer is preferably 10,000 to 200,000, and in the examples, 40,000 is used. Current demand for image quality is becoming more stringent, the toner having a number average molecular weight was prepared using a high molecular weight ε- caprolactone polymer of 10 ^four orders, the initial image is not completely meet the requirements, continuous printing, especially high temperature and high humidity The printing under such bad conditions was not satisfactory. Also, higher O
Prior to the requirement for HP permeability, high molecular weight ε-caprolactone polymers could not meet.

[0008]

Based on the above prior art, it has a low fixing temperature and good OHP permeability, and
As a result of intensive studies to obtain a toner for developing an electrostatic image having excellent storage properties, in a method for producing toner particles by a suspension polymerization method, a polymerizable monomer is converted into a colorant and a low molecular weight ε.
It has been found that the above object can be achieved by suspension polymerization in the presence of a caprolactone polymer.

[0009]

Thus, according to the present invention, a polymerizable monomer is suspended in the presence of a colorant, a release agent and an ε-caprolactone polymer having a number average molecular weight of 3,000 to 8,000. There is provided a toner for developing an electrostatic image, which is formed by turbid polymerization.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION (Method of Manufacturing Toner) The present invention will be described below in detail. The method for producing a toner for developing an electrostatic image of the present invention is produced by employing a suspension polymerization method. In the suspension polymerization method, usually, a mixed solution containing at least a polymerizable monomer and a colorant is added to an aqueous dispersion medium containing a dispersant, and the mixture is subjected to suspension polymerization to produce colored polymer particles. I do. Specifically, a colorant, a charge controlling agent, and other additives are added to the polymerizable monomer, and the mixture is uniformly dispersed by a ball mill or the like (hereinafter, referred to as a polymerizable monomer composition or a monomer mixture). This liquid mixture was poured into an aqueous dispersion medium, and stirred until the particle diameter of the droplets became uniform. After the particle diameter became uniform, a radical polymerization initiator was further added. Then, after dispersing the aqueous dispersion of the polymerizable monomer composition using a mixing device having a high shearing force and granulating into fine droplets, usually at a temperature of 5 to 200 ° C., preferably 30 to 200 ° C. Perform suspension polymerization at a temperature of １００100 ° C.

In the present invention, suspension polymerization of a polymerizable monomer is carried out in the presence of a ε-caprolactone polymer together with a coloring agent and the like. The polymerizable monomer is not particularly limited, but from the viewpoint of fixability, it is preferable to use at least one monomer that forms a polymer having a glass transition temperature of 80 ° C. or lower. Here, the glass transition temperature of the polymer is a calculated value (calculated Tg) calculated according to the type of the monomer used and the usage ratio.

(Monomer) Preferred examples of the polymerizable monomer used in the present invention include a monovinyl monomer. Specifically, styrene monomers such as styrene, vinyltoluene and α-methylstyrene; acrylic acid, methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylic Acrylic acid or methacrylic acid such as dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, etc. Derivatives of ethylene; ethylenically unsaturated monoolefins such as ethylene, propylene and butylene; vinyl halides such as vinyl chloride, vinylidene chloride and vinyl fluoride; vinyls such as vinyl acetate and vinyl propionate Ester, vinyl methyl ether, vinyl ethers such as vinyl ethyl ether, vinyl methyl ketone, vinyl ketones such as methyl isopropenyl ketone; 2-vinyl pyridine, 4-vinyl pyridine, N
Monovinyl monomers such as nitrogen-containing vinyl compounds such as vinylpyrrolidone; These monovinyl monomers may be used alone, or a plurality of monomers may be used in combination. Of these monovinyl monomers, styrene monomers or derivatives of acrylic acid or methacrylic acid are preferably used.

(Polymerization method) The polymerization of the polymerizable monomer is usually carried out by
It is performed by a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method, or the like. In the present invention, it is particularly preferable to carry out the polymerization by a suspension polymerization method.

(Dispersant) The dispersant used in the suspension polymerization method contains a colloid of a poorly water-soluble metal compound. Examples of poorly water-soluble metal compounds include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; metal oxides such as aluminum oxide and titanium oxide; Metal hydroxides such as aluminum oxide, magnesium hydroxide and ferric hydroxide; and the like. Among these, a dispersant containing a colloid of a poorly water-soluble metal hydroxide is preferable because it can narrow the particle size distribution of the polymer particles and improves the sharpness of the image. After the completion of the polymerization reaction, the water-soluble metal hydroxide remaining on the particle surface is usually removed by pickling and washing with water.
By dehydration and drying, toner particles can be obtained.

A dispersion stabilizer containing a colloid of a poorly water-soluble metal hydroxide is prepared by adjusting the pH of an aqueous solution of a water-soluble polyvalent metal compound to 7 or more with an alkali metal hydroxide. It is preferable to use a colloid of a neutral metal hydroxide.

The dispersion stabilizer is usually used in a proportion of 0.1 to 20 parts by weight based on 100 parts by weight of the monomer. If this ratio is less than 0.1 part by weight, it is difficult to obtain sufficient droplet dispersion stability of the polymerizable monomer composition, and aggregates of polymer particles are easily generated. Conversely, if it exceeds 20 parts by weight, the viscosity in the aqueous dispersion medium increases, and the distribution of the particle diameter of the polymerized toner broadens, so that the yield decreases. The reaction ratio between the water-soluble polyvalent metal salt and the alkali metal hydroxide is the chemical equivalent ratio A of the alkali metal hydroxide to the water-soluble polyvalent metal.
Is in the range of 0.4 ≦ A ≦ 1.0.

In the present invention, if necessary, a dispersant containing a water-soluble polymer can be used. Examples of the water-soluble polymer include polyvinyl alcohol, methyl cellulose, gelatin and the like. In the present invention, it is not necessary to use a surfactant,
It can be used to stably carry out polymerization within a range where the environmental dependence of the charging characteristics does not increase.

The colloid of the poorly water-soluble metal compound used in the present invention has a number particle size distribution D50 (50% cumulative value of the number particle size distribution) of 0.5 μm or less and a D90 (9% of the number particle size distribution).
(0% cumulative value) is preferably 1 μm or less.

In the present invention, optional polymerization initiators, molecular weight regulators and crosslinking agents can be used as required.

As the polymerization initiator, persulfates such as potassium persulfate and ammonium persulfate; 4,4-azobis (4
-Cyanovaleric acid), 2,2-azobis (2-amidinopropane) dihydrochloride, 2,2-azobis-2-methyl-N
-1,1-bis (hydroxymethyl) -2-hydroxyethylpropioamide, 2,2′-azobis (2,4-
Azo compounds such as dimethylvaleronitrile), 2,2′-azobisisobutyronitrile and 1,1′-azobis (1-cyclohexanecarbonitrile); isobutyryl peroxide, 2,4-di-chlorobenzoyl peroxide Diacyl peroxides such as 3,5,5-trimethylhexanoyl peroxide; bis (4-t
-Butylcyclohexyl) peroxydi-carbonate, di-n-propylperoxydi-carbonate, di-isopropylperoxydi-carbonate, di-2-
Ethoxyethyl peroxydi-carbonate, di (2-
Peroxydi-carbonates such as ethylethylperoxy) di-carbonate, di-methoxybutylperoxydi-carbonate, di (3-methyl-3-methoxybutylperoxy) di-carbonate;

(Α, α-bis-neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1 -Methyl ethyl peroxy neodecanoate, t-hexyl peroxy neodecanoate, t-butyl peroxy neodecanoate, t-hexyl peroxy pivalate,
t-butyl peroxypivalate, methyl ethyl peroxide, di-t-butyl peroxide, acetyl peroxide, dicumyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl peroxy-
Examples include peroxides such as 2-ethylhexanoate, di-isopropylperoxydicarbonate and di-t-butylperoxyisophthalate.

Further, there may be mentioned a redox initiator obtained by combining these polymerization initiators and a reducing agent. Among these, an oil-soluble radical initiator, particularly an oil-soluble radical initiator selected from organic peroxides having a 10-hour half-life temperature of 40 to 80 ° C, preferably 45 to 80 ° C and a molecular weight of 300 or less. Especially t-butylperoxy-2-
Ethyl hexanoate, t-butyl peroxy neodecanoate and t-butyl peroxy-pivalate are preferred because they cause less environmental damage due to volatile components such as odor.

[0023] The amount of the polymerization initiator used for producing the toner is usually 0.01 to 10% by weight based on the polymerizable monomer. If the content is less than 0.01% by weight, the polymerization rate is too low.
If the amount is more than the weight%, the molecular weight becomes low, which is not preferable.

Examples of the molecular weight modifier optionally used in the present invention include t-dodecyl mercaptan, n
Mercaptans such as -dodecylmercaptan and n-octylmercaptan; and halogenated hydrocarbons such as carbon tetrachloride and carbon tetrabromide.

These molecular weight modifiers are used before the start of polymerization,
Alternatively, it can be added during the polymerization. The molecular weight modifier is usually 0.0
It is used in a proportion of 1 to 10 parts by weight, preferably 0.1 to 5 parts by weight.

Further, the use of a crosslinkable monomer is effective for improving hot offset. The crosslinkable monomer is a monomer having two or more polymerizable carbon-carbon unsaturated double bonds. Specifically, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene and derivatives thereof; diethylenically unsaturated carboxylic esters such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; N, N-divinylaniline, divinyl ether and the like A divinyl compound; a compound having three or more vinyl groups; and the like. These crosslinkable monomers can be used alone or in combination of two or more. These crosslinkable monomers are
Usually, 0.05 to 5 parts by weight, preferably 0.1 to 2 parts by weight per 100 parts by weight of the polymerizable monomer (non-crosslinkable monomer).
Used in parts by weight.

(Additives) To the polymerizable monomer composition (monomer liquid), various additives such as a colorant, a releasing agent, and a charge controlling agent can be added as required.

(Colorant) In the case of carbon black as a black pigment, it is particularly preferable to use a colorant having a primary particle size of 20 to 40 nm. If it is less than 20 nm, dispersion of carbon black cannot be obtained, resulting in a toner with a lot of fog. On the other hand, if it is more than 40 nm, the amount of the polyvalent aromatic hydrocarbon compound becomes large, and a safety problem may occur. . Other black pigments include magnetic particles such as triiron tetroxide, iron manganese oxide, iron zinc oxide and iron nickel oxide.

Further, as dyes for magnetic color toners, C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modant Red 30, C.I.
I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modant Blue 7, C.I. I.
Direct Gulin 6, C.I. I. Basic Green 4,
C. I. Basic Glin 6 etc. are pigments such as graphite, cadmium yellow, mineral first yellow, navel yellow, neftol yellow S, hanziero G, permanent yellow NCG, tartrazine lake, red mouth graphite,
Molybdenum orange, permanent orange GTR, pyrazolone orange, benzidine orange G, cadmium red, permanent red 4R, watching red calcium salt, eosin lake, brilliant carmine 3B, manganese purple, fast violet B, methyl violet lake, navy blue, cobalt blue, Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue, Fast Sky Blue, Induslen Blue B
C, chrome grin, chromium oxide, pigment grin B,
Malachite green lake, final yellow logulin G and the like.

Examples of the magenta color pigment for full-color toner include C.I. I. Pigment Red 1, 2, 3, 4, 5,
6, 7, 8, 9, 10, 11, 12, 13, 14, 1
5, 16, 17, 18, 19, 21, 22, 23, 3
0, 31, 32, 37, 38, 39, 40, 41, 4
8, 49, 50, 51, 52, 53, 54, 55, 5
7, 58, 60, 63, 64, 68, 81, 83, 8
7, 88, 89, 90, 112, 114, 144, 14
6, 122, 123, 163, 184, 185, 20
2, 206, 207 and 209, C.I. I. Pigment Violet 19, C.I. I. Butt Red 1, 2, 1
0, 13, 15, 23, 29 and 35 and the like, as magenta dyes, C.I. I. Solvent Red 1, 3, 8,
23, 24, 25, 27, 30, 49, 81, 82, 8
3, 84, 100, 109 and 121, C.I. I. Disperse Red 9, C.I. I. Solvent Violet 8, 13, 14, 21 and 27, C.I. I. Oil-soluble dyes such as Disperse Violet 1; I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 1
8, 22, 23, 24, 27, 29, 32, 34, 3
5, 36, 37, 38, 39 and 40, C.I. I. Basic violet 1, 3, 7, 10, 14, 15, 2,
And basic dyes such as 1, 25, 26, 27 and 28.

Cyan color pigments for full-color toners include C.I. I. Pigment Blue 2, 3, 15, 16 and 17, C.I. I. Bat Blue 6, C.I. I. Acid Blue 45 and a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted on the phthalocyanine skeleton.

The yellow color pigments for full-color toners include C.I. I. Pigment Yellow 1, 2, 3, 4,
5, 6, 7, 10, 11, 12, 13, 14, 15, 1,
6, 17, 23, 65, 73, 83, 90, 13815
5, 180, and 185, C.I. I. Bat Yellow 1,
3 and 20 and the like.

(Release Agent) The release agent used in the present invention is:
It is not limited as long as it is generally used as a release agent for a toner. A hydrophobic compound that dissolves less than 3 g, preferably 2 g or less, more preferably 1 g or less with respect to 100 g of a polymerizable monomer (hereinafter referred to as a mold release agent) Agent A)
And those soluble in a polymerizable monomer (hereinafter, sometimes referred to as a releasing agent B), and these can be used alone or in combination.

Specific examples of the release agent A include low-molecular-weight polyolefin waxes such as low-molecular-weight polyethylene, low-molecular-weight polypropylene, and low-molecular-weight polybutylene, low-molecular-weight oxidized polypropylene, and low-molecular-weight terminals in which the molecular terminals are substituted with epoxy groups. Terminal-modified polyolefin waxes such as modified polypropylene and block polymers of these and low-molecular-weight polyethylene, oxidized low-molecular-weight polyethylene at the molecular end, low-molecular-weight polyethylene having molecular terminals substituted with epoxy groups, and block polymers of these with low-molecular-weight polypropylene; candelilla, carnauba , Rice, wood wax, jojoba, etc .; plant-based natural waxes; petroleum-based waxes such as paraffin, microcrystalline, petrilactam and modified waxes; montan, ceresin, ozokerai Alone or in combination of two or more such are exemplified; synthetic waxes such as Fischer-Tropsch wax; mineral waxes like.

Of these, synthetic waxes (especially shell
Product names “FT-100” and “FT-003” manufactured by MDS
0 "," FT-0050 "," FT-0070 "," F
T-0165 "," FT-1155 "," FT-60 "
S ”and Fischer-Tropsch wax such as Sasol wax (trade name, manufactured by Sasol) and“ Viscol 660P ”of low molecular weight polypropylene wax,
“Viscole 550P” (all trade names, manufactured by Sanyo Chemical Industries, Ltd.) and microcrystalline wax are preferred.
Among them, those having an endothermic peak temperature in the range of 30 to 200 ° C., preferably 50 to 180 ° C., and 60 to 160 ° C. in a DSC curve measured by a differential scanning calorimeter are particularly preferable. The endothermic peak temperature is ASTM D
3418-82.

The release agent A may be mixed with the polymerizable monomer and polymerized immediately. However, all or one or more of one or more monomers (such as a styrene monomer) used in the production of the toner may be used. Part, and pulverize with a bead mill or the like.
It may be pulverized until the volume average particle diameter measured by 000J (manufactured by Shimadzu Corporation) becomes 2 μm or less, preferably 1.5 μm or less, more preferably 1 μm or less, and 0.05 μm or more. The amount of the monomer used in the pulverization is 5 to 15 times (by weight) the release agent A, preferably 8 to 12 times.
It is twice. When the particle size distribution of the release agent A is narrow, the droplets of the polymerizable monomer composition are stabilized, and the storage stability of the toner is also improved. The stability of the droplet is as follows: the particle size distribution represented by the ratio Dv / Dp of the volume average particle size Dv to the number average particle size Dp measured by SALD-2000J (manufactured by Shimadzu Corporation) is 1.0 to 3.0. , Preferably 1.0 to 2.5, more preferably 1.0 to 2.0.

The release agent B is soluble in the polymerizable monomer as described above. Here, “soluble in a polymerizable monomer” means that 3 g or more, preferably 5 g or more is dissolved in 100 g of the polymerizable monomer at 25 ° C., and is a main component of the polymerizable monomer. Those that are soluble in the polymerizable monomer at 25 ° C. and have a softening point (or melting point) higher than the polymerization temperature of the polymerizable monomer cause the shape of the release agent B to be spherical in the monomer, This is preferable because bleeding does not occur on the toner surface after polymerization. As such a release agent B, a polyfunctional ester compound which is a condensate of a trifunctional or higher-functional alcohol and a carboxylic acid is preferable. In the case of the release agent a insoluble in the styrene monomer, once
By heating the core polymerizable monomer to a temperature equal to or higher than the melting point of the release agent a, spheroidization in the core polymerizable monomer is possible. However, at the stage of lowering the temperature and the stage of polymerization of the core monomer, bleeding easily occurs on the toner surface, and the sufficient effect of the present invention cannot be obtained.

Examples of the trifunctional or higher functional alcohol include aliphatic alcohols such as glycerin, pentaerythritol and pentaglycerol; alicyclic alcohols such as phloroglucitol, queritol and inositol; aromatic alcohols such as tris (hydroxymethyl) benzene Sugars such as D-erythrose, L-arabinose, D-mannose, D-galactose, D-fructose, L-rhamnose, saccharose, maltose, lactose; and the like; erythritol, D-trait, L-arabit,
Examples thereof include sugar alcohols such as adnit and xylit. Of these, pentaerythritol and dipentaerythritol are preferred.

Examples of the carboxylic acid include acetic acid, butyric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, margaric acid, arachidic acid, and cerotic acid. Carboxylic acids such as melixic acid, ericic acid, brassic acid, sorbic acid, oleic acid, linoleic acid, linolenic acid, behenylic acid, tetrolic acid, xymenic acid; cyclohexanecarboxylic acid, hexahydroisophthalic acid, hexahydroterephthalic acid , 3,4
Alicyclic carboxylic acids such as 5,6-tetrahydrophthalic acid; aromatic carboxylic acids such as benzoic acid, toluic acid, cumic acid, phthalic acid, isophthalic acid, terephthalic acid, trimesic acid, trimellitic acid, and hemimelitic acid; be able to. Among them, carboxylic acids having 10 to 30 carbon atoms, preferably 13 to 25 carbon atoms, particularly aliphatic carboxylic acids having the carbon number, more specifically, palmitic acid, myristic acid, and lauric acid are suitable.

In the polyfunctional ester compound used in the present invention, the plurality of carboxylic acids bonded to the tri- or higher functional alcohol may be different or the same, but preferably, the plurality of carboxylic acids are the same. The difference between the maximum value and the minimum value of the number of carbon atoms in the acid is 9 or less, preferably 5 or less. Specifically, pentaerythritol = tetrastearate, pentaerythritol = tetramyristate,
Examples thereof include pentaerythritol = tetralaurate, dipentaerythritol = hexalaurate, and glycerol = triaraquinic acid. The release agent A is used in an amount of 0 to 10 parts, preferably 0 to 5 parts, more preferably 0 to 3 parts, based on 100 parts of the core monomer. Further, the release agent B is based on 100 parts of the core monomer,
0 to 50 parts, preferably 0 to 30 parts, more preferably 0 to 20 parts are used.

(Charge Control Agent) As the charge control agent, a commonly used positive or negative charge control agent can be used. For example, a metal complex of an organic compound having a carboxyl group or a nitrogen-containing group, a metal-containing dye, nigrosine and the like can be mentioned. More specifically, Spiron Black TRH (Hodogaya Chemical), T-77 (Hodogaya Chemical), Bontron S-34 (Orient Chemical), Bontron E-84 (Orient Chemical), Charge control resins such as Bontron N-01 (manufactured by Orient Chemical), Copy Blue-PR (manufactured by Hoechst), quaternary ammonium salt-containing resins, sulfonic acid group-containing resins, etc., among which quaternary ammonium salts A resin having a polar group such as a resin containing a sulfonic acid group and a resin containing a sulfonic acid group and soluble in styrene is preferred. The charge control agent is a polymerizable monomer 100
Usually, 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight is used based on parts by weight.

(Dispersant) A lubricant such as oleic acid or stearic acid; a dispersing agent such as a silane-based or titanium-based coupling agent; May be contained in the monomer composition.
Such a lubricant or dispersant is generally used at a ratio of about 1/1000 to 1/1 based on the weight of the colorant.

(Shell material) The ε-caprolactone ring-opening polymer can be obtained, for example, by ring-opening polymerization using a catalyst such as a metal oxide or an organometallic compound. When glycol is used as an initiator, a polyester having a hydroxyl group at a terminal can be obtained. For example,
The ring-opened polymer of ε-caprolactone can be usually obtained by reacting ε-caprolactone with a diol such as ethylene glycol or diethylene glycol in the presence of a catalyst. As the catalyst, an organic tin compound, an organic titanium compound, an organic tin halide compound and the like are generally used, and are added at a ratio of about 0.1 to 5000 ppm,
The polycaprolactone resin can be obtained as a ring-opened polymer by polymerizing at 100 to 230 ° C., preferably under an inert atmosphere. The lactone ring-opening polymer may be one whose terminal is modified to be, for example, a carboxyl group.

The molecular weight of the ε-caprolactone ring-opened polymer described above is such that the number average molecular weight determined by gel permeation chromatography (GPC) is 3,000.
~ 8,000. The melting point of this ring-opened polymer (T
m) is usually about 50 to 60 ° C. Further, the ring-opening polymer is a thermoplastic aliphatic polyester resin having high crystallinity. Such a lactone ring-opening polymer can be synthesized by a conventional method, but a commercially available product may be used. Commercially available products include, for example, PLAC manufactured by Daicel Corporation.
CEL series 230, 230T, 240 and the like (highly crystalline polycaprolactone having a melting point of 55 to 58 ° C.).

Toner for Developing an Electrostatic Image Image The toner for developing an electrostatic image of the present invention comprises a polymer component 9 derived from a polymerizable monomer.
0 to 99% by weight, preferably 91 to 98% by weight, more preferably 92 to 97% by weight, and 1 to 10% by weight, preferably 2 to 9% by weight, more preferably 3 to 9% by weight of the ring-opening polymer component of lactone. 8% by weight. The thickness of the shell is calculated from the particle size of the core and the amount of the added shell. Since the polymer component derived from the polymerizable monomer forms a core, and the lactone ring-opening polymer forms a shell,
If the proportion of the ring-opening polymer component of the lactone is too small, the blocking resistance (preservability) decreases, and if the proportion is too large, the effect of improving fixability and OHP permeability is reduced, and the shape is reduced by suspension polymerization. , It is difficult to obtain a toner having excellent uniformity and various characteristics.

The toner for developing electrostatic images of the present invention is usually
Volume average particle diameter is 1 to 10 μm, preferably 3 to 8 μm
Spherical fine particles having a sharp particle size distribution having a particle size distribution (volume average particle size / number average particle size) of 1.7 or less, preferably 1.5 or less, more preferably 1.3 or less. When the toner for developing an electrostatic image of the present invention is used, the fixing temperature can be reduced to a low temperature of 80 to 180 ° C., preferably 100 to 150 ° C., and it does not aggregate during storage and has excellent storage stability. I have. Further, the toner for developing an electrostatic image of the present invention has excellent fixability to an OHP sheet and has good OHP transparency, so that it is suitable as a toner for OHP.

[0047]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to only these examples. Parts and percentages are by weight unless otherwise specified.

The method for measuring physical properties is as follows. (1) Particle Size of Toner The particle size of the toner particles is determined by using a Multisizer (manufactured by Coulter Inc.) using a volume average particle size (dv) and a particle size distribution, that is, a ratio of the volume average particle size to the number average particle size (dp) (Dv / d
p) was measured. The measurement by the multisizer was performed under the following conditions. Aperture diameter: 100 μm Medium: Isoton II Concentration: 15% Number of measured particles: 50,000

(2) Shell Thickness In this case where the thickness of the shell is small, calculation was made using the following equation. (X + r) / r = (1 + s / 100) ^1/3 (1) where, r: radius of core particle size (volume particle size of multisizer: μm) before addition of shell monomer x: shell thickness (μm) S: number of parts of shell monomer added (based on 100 parts by weight of core monomer) ρ: density of shell resin (g / cm ³ ) = 1

(3) Preservation of Toner The developer is placed in a sealable container, and after sealing, the container is immersed in a thermostatic water bath maintained at a temperature of 55 ° C. After a lapse of 8 hours, the container is taken out of the thermostatic bath, and the developer in the container is transferred onto a 42-mesh sieve. At this time, the developer is gently taken out of the container and carefully transferred to the sieve so as not to destroy the aggregated structure of the developer in the container. After the sieve was vibrated for 30 seconds under the condition of a vibration intensity of 4.5 using the above-mentioned powder measuring machine, the weight of the developer remaining on the sieve was measured and defined as the weight of the aggregation developer. The ratio (% by weight) of the weight of the aggregation developer to the weight of the developer initially placed in the container was calculated. The measurement was performed three times for one sample, and the average value was used as an index of the storage stability.

(4) Light Transmittance A commercially available non-magnetic one-component developing type printer (four-sheet machine) was used to resolve the temperature of the fixing roll part so that the temperature of the fixing roll could be changed to 150 ° C. Set, print a solid image on a commercially available OHP sheet, place it on the OHP, and project it. O: transparent colored images, Δ: black spots in some parts, ×: black spots more than colored areas And However, a print density of 1.0 to 1.2 was used.

(5) Evaluation of Initial Image Quality Measurement of Print Density (ID) Print density (ID) was evaluated using a Macbeth reflection densitometer.
"Black solid portion" was measured, and 1.4 or more was evaluated as "O", 1.3 or more as "?", And 1.3 or less as "X".・ Measurement of photoreceptor fog The toner in the fog area on the photoreceptor drum is transferred to paper with a mending tape, and the reflectance value measured with a whiteness meter is reflected when only the mending tape is affixed to the paper. The ratio was subtracted from the value measured by a whiteness meter, and a developer of 2 or less was evaluated as ○, 5 or less as Δ, and 10 or more as x.・ Resolution: 1 dot line and 1 dot white line, and 2 dot line and 2 dot white line are printed at the same time and observed with an optical microscope to see if the image quality can be reproduced. did. ○: One dot line and one dot white line are reproduced. Δ: One-dot line and one-dot white line cannot be reproduced, but two-dot line and two-dot white line can be reproduced. X: A 2-dot line and a 2-dot white line could not be reproduced.

(6) Continuous printing evaluation Continuous printing was carried out from the initial stage at 30 ° C. × 80% (relative humidity) with the above-mentioned printer, and the print density was 1.35 or more with a reflection densitometer (manufactured by Macbeth). A toner with a fog in the image area of 5% or less measured by a whiteness meter (manufactured by Nippon Denshoku Co., Ltd.) (toner) capable of continuing 10,000 sheets or more (（) toner capable of continuing 5,000 sheets or more (△) Was evaluated as (x).

Example 1 8 parts of crystalline polycaprolactone diol A (PLACCEL 230, manufactured by Daicel Co., Ltd .; number average molecular weight = 3,000, melting point = 56 ° C.) were 100 parts of styrene / butyl acrylate (weight ratio 78:22). And a yellow pigment (Clariant, trade name "ton"
er yellow HG VP2155 ") and dispersed well. On the other hand, at room temperature, ion-exchanged water 25
An aqueous solution in which 9.5 parts of magnesium chloride (a water-soluble polyvalent metal salt) is dissolved in 0 parts of sodium hydroxide and 5.8 parts of sodium hydroxide (alkali metal hydroxide) in 50 parts of ion-exchanged water is stirred. A magnesium hydroxide colloid (poorly water-soluble metal hydroxide colloid) dispersion was prepared by gradually adding. The particle size distribution of the colloid was measured using a Microtrac particle size distribution analyzer (manufactured by Nikkiso Co., Ltd.).
D50 (50% cumulative value of number particle size distribution) is 0.36 μm
And D90 (90% cumulative value of the number particle size distribution) is 0.80.
μm. In the measurement by this microtrack particle size distribution measuring instrument, the measurement range = 0.12 to 704 μm
m, measurement time = 30 seconds, medium = ion-exchanged water.

The polymerizable monomer composition for a core is added to the colloidal magnesium hydroxide dispersion obtained above at room temperature, and the mixture is stirred until the droplets are stabilized. After adding 6 parts of butylperoxy-2-ethylhexanoate ("Perbutyl O" manufactured by NOF Corporation),
The droplets of the monomer mixture were granulated by high shear stirring at 15,000 rpm for 30 minutes using an Ebara milder. The aqueous dispersion of the granulated monomer mixture was put into a 10 L reactor equipped with a stirring blade, and the polymerization reaction was completed at 90 ° C. for 8 hours.

The aqueous dispersion of the core-shell type polymer particles obtained above was acid-washed (25 ° C., 10 minutes) with sulfuric acid to adjust the pH of the system to 4 or less at room temperature while stirring. After separating the water, the ion-exchanged water 5
The slurry was re-slurried by adding 00 parts and washed with water. Thereafter, dehydration and water washing were repeated several times at room temperature, and the solid content was separated by filtration, followed by drying at 40 ° C. for 3 days and night with a drier to obtain polymer particles.

The volume average particle diameter of the dried toner is 6.5 μm.
The number% of 5 μm or less was 20%, and the volume% of 16 μm or more was 1.2%. As a result of the calculation, the layer thickness of the shell was 0.08 μm. Toner 10 obtained above
In 0 parts, as an abrasive, a large particle size silica (trade name “RX-50”, manufactured by Nippon Aerosil Co., Ltd., particle size 40 μm, HMDS
Processed product) 0.3 parts by weight and 0.5 parts of colloidal silica (trade name “R202” manufactured by Degussa, particle size: 14 nm, DMPS-processed product) are added, mixed using a Henschel mixer, and the developer is added. Obtained.

Example 2 Crystalline polycaprolactone B having a weight average molecular weight of 8000, 2 parts of styrene / butyl acrylate (weight ratio: 80.5: 19.5) 100
And 5 parts of a magenta pigment (trade name "toner magenta E-02", manufactured by Clariant) was added and dispersed well. This was dispersed in the aqueous magnesium hydroxide solution of Example 1, stirred, 6 parts of a polymerization initiator (t-butylperoxy-2-ethylhexanoate) was added, and the mixture was homogenized, followed by 8 hours at 90 ° C. The mixture was heated and stirred to complete the polymerization. The reaction system was returned to room temperature, a 20% aqueous sulfuric acid solution was added to adjust the pH to 2, suction filtration was performed, and the filtrate was thoroughly washed with water, and then dried at 40 ° C. for 3 nights.
Spherical resin particles were obtained. An external additive was added to the particles in the same manner as in Example 1 to obtain a developer.

With respect to the resin particles obtained in these examples, the volume average particle diameter, the shape of the particles, and the particle size distribution were measured, and the storability, light transmittance, OHP transmittance, initial image, The continuous printing was evaluated. Table 1 shows the results.

Comparative Example 1 In the same manner as in Example 1, crystalline polycaprolactone C having a weight average molecular weight of 2,000 (PLACCEL 220, manufactured by Daicel Corporation; melting point =
A developer was obtained in the same manner as in Example 1 except that the temperature was changed to 50 ° C.). Table 1 shows the results of evaluation of the developer.

Comparative Example 2 The procedure of Example 2 was repeated, except that the crystalline polycaprolactone D having a weight average molecular weight of 10,000 was replaced by PLACEL H1P (manufactured by Daicel Corporation; melting point = 60 ° C.). A developer was obtained in the same manner as described above. Table 1 shows the results of evaluation of the developer.

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[Table 1]

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According to the present invention, there is provided a toner for developing an electrostatic image, which has a low fixing temperature and a good OHP transparency, and has excellent storage stability.

Claims (3)

[Claims] An electrostatic charge obtained by subjecting a polymerizable monomer to suspension polymerization in the presence of a colorant, a release agent, and an ε-caprolactone polymer having a number average molecular weight of 3,000 to 8,000. Image developing toner. 2. The toner according to claim 1, wherein 1 to 10 parts by weight of an ε-caprolactone polymer is added to 100 parts by weight of the polymerizable monomer. 3. The electrostatic charge image developing toner according to claim 1, wherein the release agent comprises a polyfunctional ester compound comprising a trifunctional or higher-functional alcohol and a carboxylic acid.