JP2574209B2 - Toner for electrostatic images - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used for developing an electrostatic image formed in electrophotography, electrostatography, electrostatic recording, and the like. .

[Prior Art] Generally, an electrostatic image is developed with a toner, which is a colored powder, to form a toner image, and this toner image is fixed as it is or after being transferred to a transfer paper or the like.

This toner usually has a polymer as a binder component,
It is prepared by melting and mixing components composed of carbon black and other components mainly containing a colorant and a charge control agent.

Conventionally, styrene-based resins have been the mainstream as the binder component, but recently, saturated polyester resins that have a large negative chargeability and are suitable for high-speed copying with excellent constant-temperature fixing properties have attracted attention, and many studies have been conducted. ing.

[Problems to be Solved by the Invention] The present invention and the like have also repeatedly studied toners using a polyester-based resin.
A portion of the toner component is transferred to a generally used fixing heat roller and stains the surface of the transfer paper supplied thereafter, or further transfers to a pressure roller pressed by the heat roller to stain the back surface of the transfer paper. And found that there was a problem.

Originally, the fixing property and the anti-offset property are contradictory required properties, but preventing the occurrence of the offset phenomenon while maintaining the low-temperature fixing property is an issue that must be solved by all means when commercializing polyester resin toner. is there.

For this reason, in a toner using a polyester-based resin, there is a method of using a partially crosslinked macromolecule using a trifunctional or higher functional component such as trimellitic acid as a monomer of the raw material polyester resin. When a trifunctional or higher functional component such as trimellitic acid is used as a monomer, there is a drawback that there is no effective method for stopping the polymerization reaction other than lowering the temperature to obtain a desired molecular weight and a desired degree of crosslinking. In spite of its excellent properties, it has been difficult to spread toners using polyester resins.

As a countermeasure, the present applicant has previously described (a) a saturated polyester resin, (b) a polyfunctional cyanate ester containing two or more cyanate groups in the molecule or the cyanate ester prepolymer and (c) the cyanate ester prepolymer. A toner composition comprising a resin curing catalyst has been proposed.

However, the present inventors have further studied the properties of the toner composition, and have found that if the fixing temperature range of the toner composition is expanded, a more practical product can be obtained.

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve such problems, and as a result, by using a specific amount of two kinds of saturated polyester resins having different acid values, it is possible to obtain a desired electrostatic image. The inventors have found that a toner can be obtained, and have completed the present invention.

That is, the present invention relates to a toner using a saturated polyester resin used for developing an electrostatic image as a binder resin component, wherein the saturated polyester resin has an acid value of the acid value of the resin [I] having a lower acid value. Higher resin [I
I] the acid value ratio (hereinafter simply referred to as acid value ratio) is 1.5 or more, and Is used in a ratio of 0.3 to 0.9 on a weight basis, and (b) a polyfunctional cyanate prepolymer containing two or more cyanato groups in the molecule; A toner for electrostatic images, characterized by using a polyester resin composition containing the curing catalyst of (a).

 Hereinafter, the configuration of the present invention will be described.

The saturated polyester resin of the present invention is obtained by condensing an optional acid component and a polyhydric alcohol component. Acid components include terephthalic acid, isophthalic acid, orthophthalic acid, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, trimethyladipic acid, pimelic acid, 2,2-
Dimethyl glutaric acid, azelaic acid, sebacic acid, 1,
3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4
-Cyclohexanedicarboxylic acid, 2,5-norbornanedicarboxylic acid, 1,4-naphthalic acid, diphenic acid, 4,4-
Oxybenzoic acid, diglycolic acid, thiodipropionic acid, 2,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, or the above dicarboxylic acid component and benzoic acid, or rosin, hydrogenated rosin, disproportionated rosin, etc. Those using a monocarboxylic acid such as a rosin derivative in combination are exemplified.

These may be acid anhydrides, esters, chlorides and the like, and include, for example, dimethyl 1,4-cyclohexanedicarboxylate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl isophthalate, dimethyl terephthalate, and diphenyl terephthalate.

In addition to the above, if the amount is small (unsaturated), unsaturated carboxylic acids such as maleic acid and fumaric acid, and trivalent or higher polycarboxylic acids, such as trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4-Methylcyclohexene-1,2,3-tricarboxylic anhydride and trimesic acid can also be used.

Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, and 2,2-dimethyl-1,3-propane. Diol (neopentyl glycol), 2-ethyl-2-isobutyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol,
6-hexanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,
2-cyclohexane dimethanol, 1,3-cyclohexane dimethanol, 1,4-cyclohexane dimethanol, 2,
2,4,4-tetramethyl-1,3-cyclobutanediol, 4,
4'-thiodiphenol, 4,4 '-(2-kylbornylidene) diphenol, 4,4'-dihydroxybiphenol, o-, m- and p-dihydroxybenzene, 4,4'-
Isopropylidenephenol, 4,4'-isopropylidenebis (2,6-dichlorophenol), 2,5-naphthalenediol, and p-xylenediol.

In addition to the above, if the amount is small, trihydric or higher polyhydric alcohols such as pentaerythritol, dipentaerythritol,
Tripentaerythritol, glycerin, trimethylolpropane, trimethylolethane, 1,3,6-hexanetriol and the like can also be used. Further, a compound containing a hydroxyl group and a carboxyl group in the molecule, for example, a low molecular weight condensate of terephthalic acid and ethylene glycol can also be used.

In addition to the acid component and the polyhydric alcohol component, sulfonate groups can be introduced by a generally known method. Representative examples of the condensation component used in this case include 5-sodiosulfoisophthalic acid and 5-potassium sulfoisophthalic acid, but are not limited thereto.

No special operation is required to produce the polyester resin by condensing the acid component and the polyhydric alcohol component, and any conventionally known method may be used, but a typical example is 1.0 to 1.5 times the molar amount of the acid component. Is charged into a reactor together with a catalyst, and the temperature is raised to 140 to 260 ° C. to perform dehydration condensation. As the catalyst used in this case, zinc acetate, zinc chloride, stannous lauryl, butyltin oxide, octyltin oxide and the like are used, and these are usually charged in an amount of 0.05 to 0.15% by weight based on the dicarboxylic acid.

A solvent is not particularly required, but if desired, methyl acetate,
A non-winning solvent such as benzene, acetone, xylene, and toluene may be used.

The glass transition temperature of the polyester resin is preferably from 30 to 75C, more preferably from 45 to 70C. Also, the number average molecular weight is 3,00
Weight average molecular weight of 1.0 × 10 ⁴ or more at 0 to 8,000, preferably
5.0 × 10 ⁴ to 50 × 10 ⁴ are preferable.

The acid value of the resins [I] and [II] may be appropriately adjusted at the time of production, and usually, the acid value is such that [I] is less than 15 KOHmg / g,
Preferably, it is controlled to 0.1 to 10 KOH mg / g, and [II] is controlled to 15 KOH mg / g or more, preferably 15 to 40 KOH mg / g.
The acid number ratio between the two resins must be at least 1.5, preferably at least 2. When the ratio is less than 1.5, the fixing temperature width is narrow and the practicality is poor.

[I] and [II] are Must be mixed at a ratio of 0.3 to 0.9, preferably 0.4 to 0.7 on a weight basis, and the effect of the present application is hardly obtained outside this range.

The polyfunctional cyanate ester containing two or more cyanato groups (-OCN) in the molecule, which is the component (b) of the present invention to be blended with the polyester resin, or a suitable as the cyanate ester prepolymer, General formula (1): R (OCN) (1) (wherein n is an integer of 2 or more, usually 5 or less, and R is an aromatic organic group which may contain a plurality of rings. Wherein the cyanato group is bonded to the aromatic ring of the organic group). Specifically, 1,3- or
1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-, 1,4-, 1,6-, 1,8-, 2,6- or 2,7-dicyanatonaphthalene , 1,3,6-tricyanatonaphthalene, 4,4-
Dicyanatobiphenyl, bis (4-dicyanatophenyl) methane, bis (3,5-dimethyl-4-dicyanatophenyl) methane, 2,2-bis (4-cyanatophenyl)
Propane, 2,2-bis (3,5-dichloro-4-cyanatophenyl) propane, 2,2-bis (3,5-dibromo-4-cyanatophenyl) propane, 2,2-bis (3, 5-dimethyl-4-cyanatophenyl) propane, bis (4-cyanatophenyl) ether, bis (4-cyanatophenyl)
Thioether, bis (4-cyanatophenyl) sulfone, tris (4-cyanatophenyl) phosphite, tris (4-cyanatophenyl) phosphate, polyfunctional novolak obtained by reaction of novolak with cyanogen halide Cyanate (USP-4P022P755; 3,448,07
9), a polyfunctional polycarbonate cyanate (USP-4,026,913; DE-2,61) obtained by reacting a polycarbonate oligomer having a terminal -OH group with a cyanogen halide.
1,796), and styryl-pyridine-cyanate obtained by reacting poly-hydroxy-styryl-pyridine obtained by reacting hydroxybenzalaldehydes with alkyl-substituted pyridines and cyanogen halide (USP-4,578,439). And so on. In addition to these, USP-
3,553,244; 3,755,402; 3,740,348; 3,595,900; 3,694,410;
4,116,946, BP-1,305,967; 1,060,933, DE-1,190,184;
Cyanate esters described in 1,195,764 and the like can also be used.

Further, as a prepolymer obtained by polymerizing the above-mentioned polyfunctional cyanate in the presence of a mineral acid, a Lewis acid, salts such as sodium carbonate or lithium chloride, and phosphates such as tributylphosphine, etc. It can also be used as a prepolymer with polyfunctional amines.

In the present invention, the amount of the component (b) is 0.5 to 10 parts by weight, preferably 1.0 to 5 parts by weight, particularly 1.0 to 2.5 parts by weight based on 100 parts by weight of the saturated polyester resin. If the amount is less than 0.5 parts by weight, it is difficult to obtain the effects of the present invention, while 10
It is not preferable to mix the compound in an amount exceeding the weight part because an excessive crosslinking reaction such as an increase in the flow start temperature occurs.

In addition, the catalyst of the component (c) of the present invention can be a catalyst which is generally known for the purpose of accelerating the curing of the component (a).

Examples of such compounds include organic peroxides exemplified by benzoyl peroxide, lauroyl peroxide, capryl peroxide, acetyl peroxide, parachlorobenzoyl peroxide, di-tert-butyl-di-perphthalate, and the like; azo Azo compounds such as bisnitrile; 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 1-
Benzyl-2-methylimidazole, 1-propyl-2
-Methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1
Imidazoles exemplified by -cyanoethyl-2-ethyl-4-methylimidazole, 1-guanaminoethyl-2-methylimidazole, furthermore, adducts of carboxylic acids or anhydrides thereof to these imidazoles; N-dimethylbenzylamine, N, N-dimethylaniline, N, N-dimethyltoluidine, N, N-dimethyl-p-
Anisidine, p-halogeno-N, N-dimethylaniline,
2-N-ethylanilinoethanol, tri-n-butylamine, pyridine, quinoline, N-methylmorpholine,
Triethanolamine, triethylenediamine, N, N,
Tertiary amines such as N ', N'-tetramethylbutanediamine, N-methylpiperidine; Phenols such as phenol, xylenol, cresol, resorcin, catechol, phloroglysin; lead naphthenate, lead stearate, naphthenic acid Organic metal salts such as zinc, zinc octylate, tin oleate, stannous lauryl, dibutyltin malate, manganese naphthenate, cobalt naphthenate, and iron acetylacetone; these organic metal salts can be used as hydroxyl-containing compounds such as phenol and bisphenol. Inorganic metal salts such as SnCl ₃ , ZnCl ₂ , and AlCl ₃ ; dibutyltin oxide, dioctyltin oxide, and other organic tin compounds such as alkyltin and alkyltin oxide; maleic anhydride, phthalic anhydride, Lauric anhydride, pyromellitic anhydride, trime anhydride Tsu DOO acid, hexahydrophthalic anhydride, hexahydrophthalic anhydride, trimellitic acid, acid anhydrides such as hexahydrophthalic anhydride, pyromellitic acid and the like.
Among these catalysts, organometallic salts, dibutyltin oxide,
Organic tin compounds such as dioctyltin oxide, other alkyltins, and alkyltin oxides are particularly preferred.

The amount of the catalyst to be used is sufficient in the range of the amount of the catalyst in a general sense. For example, it is used in an amount of 10% by weight or less, usually about several% with respect to the component (a).

In preparing the toner of the present invention, the above-mentioned saturated polyester resin composition, a colorant, and a charge control agent, if necessary, are melt-mixed: instead of the saturated polyester resin composition, a saturated polyester resin; )component,
Melt-mixing the component (c) with a colorant and, if necessary, a charge control agent; a so-called masterbatch is prepared by blending a large amount of the component (b) and the component (c) with a saturated polyester resin; By melting and mixing a saturated polyester resin, a coloring agent, and a charge control agent as required. For the compounding, equipment such as an extruder, a pressure-type kneader, and two rolls are used, and the melting temperature is 120 to 180 ° C. and the melting time is 30 seconds to 5 minutes.
It is preferable to carry out in about minutes.

Colorants include carbon black, nigrosine dye, aniline blue, calco oil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachide green oxalate, lamp black, and kosengengara And the like.

At the time of preparing the toner of the present invention, if necessary, known auxiliaries such as resins for binders other than the saturated polyester resin, which is a main component of the present invention, and polyolefin wax and other waxes can be added.

In the case of using a compound to which a metal such as phthalocyanine blue is coordinated in preparing the toner, (b)
Since the components may react with these colorants to cause a decolorization reaction or the like, it is preferable to use a method such as a composition or a masterbatch previously blended with the saturated polyester resin for the component (b).

[Function] The present invention provides a toner having a wider fixing temperature range by using saturated polyester resins having different acid values.

EXAMPLES Hereinafter, the present invention will be described with reference to examples and the like. In the examples and the like, parts and percentages are by weight unless otherwise specified.

Manufacture of polyester resin. [I] -1 0.5 mole of terephthalic acid, 0.5 mole of isophthalic acid, 0.9 mole of ethylene glycol, 0.2 mole of diethylene glycol,
0.0003 mol of dibutyltin oxide was added under nitrogen atmosphere to 160
After reacting for 4 hours at a temperature between 220C and 220C, the supply of nitrogen was stopped. Subsequently, the reaction was performed under a reduced pressure of 500 mmHg until the acid value became 5 KOHmg / g.

The obtained polyester resin has a melt viscosity at 100 ° C of 6 × 10 ³ poise (Shimadzu Flow Tester CFT-500).
, Measurement conditions; orifice diameter 1 mm, orifice length 10 m
m, load: 30 kg, the same applies hereinafter). The glass transition temperature was 59 ° C. (measured by DSC7, manufactured by PerkinElmer, and the same applies hereinafter).

[I] -2 0.7 mol of terephthalic acid, 0.3 mol of isophthalic acid, 0.6 mol of ethylene glycol, 0.4 mol of neopentyl glycol, 0.1 mol of triethylene glycol and 0.0003 mol of dibutyltin oxide at 160 ° C. to 220 ° C. for 4 hours in a nitrogen atmosphere After the reaction, the supply of nitrogen was stopped, and the reaction was performed under reduced pressure of 500 mmHg until the acid value became 7 KOHmg / g.

The obtained polyester resin had a melt viscosity at 100 ° C. of 4 × 10 ³ poise and a glass transition temperature of 58 ° C.

[I] -3 When the acid value in the reaction of [I] -2 reached 13 KOH mg / g, the reaction was stopped to obtain a polyester resin.

[II] -1 One volume four-necked flask equipped with a packed column containing 0.8 mol of terephthalic acid, 0.2 mol of isophthalic acid, 0.4 mol of ethylene glycol, 0.6 mol of bisphenol A propylene oxide adduct, 0.03 mol of glycerin and 0.0003 mol of dibutyltin oxide , Was cooled to 180 ° C under a nitrogen atmosphere, and 0.05 mol of phthalic anhydride was additionally charged.
The reaction was performed at 0 ° C. for 30 minutes.

The supply of nitrogen was stopped, 0.0015 mol of dibutyltin oxide was added, and the mixture was stirred for 30 minutes under a reduced pressure of 500 mmHg to terminate the reaction.

The obtained polyester resin has an acid value of 25 KOHmg / g, a melt viscosity at 100 ° C. of 2 × 10 ⁴ poise, and a glass transition temperature of 62 ° C.
Met.

[II] -2 0.7 mol of terephthalic acid in the same flask as [II] -1
Charge 0.3 mol of isophthalic acid, 0.2 mol of ethylene glycol, 0.2 mol of disproportionated rosin monoglyceride, 0.6 mol of bisphenol A ethylene oxide adduct, 0.02 mol of trimethylolpropane and 0.0003 mol of dibutyltin oxide, and stir at 240 ° C. under a nitrogen atmosphere. The reaction was performed below. When the effluent stopped, the temperature was lowered to 180 ° C, and 0.07 mol of phthalic anhydride was additionally charged.
The reaction was continued for 0 minutes.

Then, the supply of nitrogen was stopped and dibutyltin dilaurate was added.
0015 mol was added and the mixture was stirred for 30 minutes under a reduced pressure of 500 mmHg to terminate the reaction.

The obtained polyester resin has an acid value of 32 KOHmg / g and 100 ° C.
Melt viscosity at 3 × 10 ⁴ poise, glass transition temperature 60
° C.

[II] -3 When the acid value in the reaction of [I] -2 reached 16 KOH mg / g, the reaction was stopped to obtain a polyester resin.

Examples 1-4, Comparative Examples 1-5 0.1% of dibutyltin dilaurate was added as a curing catalyst to the above polyester resin, and 88 parts thereof, 9 parts of carbon black # 44 (manufactured by Mitsubishi Chemical Corporation), Bontron S- 34
(Orient Chemical Co., Ltd.) 1 copy, Viscole 550P
2 parts of (Sanyo Kasei Kogyo Co., Ltd.) and 2 parts of 2,2-bis (4-cyanatophenyl) propane were powder mixed, and the mixture was extruded using a twin-screw extruder PCM-30 (Ikegai Iron and Steel). 6 per cylinder
The mixture was kneaded and extruded at 0 ° C., a second and third cylinders and a cylinder head at 140 ° C., a shaft rotation speed of 100 rpm, and a supply speed of 200 g / min.

The obtained extrudate was pulverized so as to pass through a 1 mm sieve, finely pulverized by a jet mill (manufactured by Nippon Pneumatic), and classified by a bypass type classifier to obtain a toner.

Image test. Using a mixture of 5 parts of toner and 95 parts of iron powder TEFV150 / 250 (manufactured by Nippon Iron Powder Co., Ltd.), an image was transferred to plain paper using an electrophotographic copying machine DC-162 (manufactured by Mita Kogyo KK). The image was taken out and passed between a Teflon-coated heat roll and a rubber-lined backup up roll at a speed of 275 mm / sec to fix the image.

The temperature of the hot roll was changed from 150 to 240 ° C, and when there was no toner adhesion to the hot roll, the offset property was good (◎),
A remarkable case is regarded as defective (x), and the normal density of the image is measured using a mending tape NO810 (manufactured by Sumitomo 3M), and the density retention rate is further measured using a Macbeth densitometer (manufactured by Macbeth).
It shows 85% or more as measured by using and shows that the fixing property is good when the fixing is sufficiently performed (◎), and poor when the fixing is insufficient.
And

 The results are shown in the table.

Examples 5 to 7 The same experiment as in Example 1 was performed except that 1,3,5-tricyanatobenzene was used instead of 2,2-bis (4-cyanatophenyl) propane.

 The results are also shown in the table.

[Effect] In the present invention, a toner satisfying both the anti-offset property and the fixing property can be manufactured at the same time, and the toner has a wide fixing temperature range, and becomes a highly practical product.

Continuation of the front page Examiner Seiji Matsumoto (56) References JP-A-62-9356 (JP, A) JP-A-2-16664 (JP, A) JP-A-61-86760 (JP, A) JP-A Sho 60-263950 (JP, A) JP-A-63-49768 (JP, A) JP-A-63-56659 (JP, A) JP-A-62-250461 (JP, A)

Claims (3)

(57) [Claims] (A) a saturated polyester resin, (b) a polyfunctional cyanate ester containing two or more cyanato groups in a molecule or a prepolymer of the cyanate ester, and (c)
In a toner for developing an electrostatic image containing a curing catalyst of the resin, two kinds of resins having different acid values are used as (a), and the acid value of the resin [I] having a lower acid value is used. The ratio of the acid value of the resin [II] having a higher acid value to the resin is 1.5 or more, and Is used in a ratio of 0.3 to 0.9 (weight basis). 2. The electrostatic image toner according to claim 1, wherein the composition comprising (a), (b) and (c) is produced by mixing at a temperature of 100 to 170 ° C. 3. The electrostatic image toner according to claim 1, wherein the curing catalyst (c) of (a) is an organometallic compound.