JPH059788B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to toner compositions used for developing electrostatic images formed in electrophotography, electrostatic photography, electrostatic recording, etc., especially toner compositions for positive charging. The present invention relates to a composition that can be used for. [Prior Art] Generally, an electrostatic image is developed with 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. Normally, toner consists of a binder component, a coloring component,
It is prepared by blending a charge control agent, melting and mixing under heating, and then pulverizing to a predetermined particle size. Toner performance is greatly influenced by binder components. In this case, to make a negatively charged toner, the binder resin may have an acid value, and to make a positively charged toner, an amine group or a quaternary ammonium base may be introduced into the binder resin. Various resins are known as binder components for toners, but recently, resins have been developed that have high chargeability and excellent low-temperature fixing properties, making them suitable for high-speed copying, and that are also suitable for printing on vinyl chloride sheets, films, etc. Polyester resin binders are attracting attention because they do not cause the printed surface to become unclear due to plasticizers when they are laminated (in other words, they have excellent plasticizer resistance). Examples of applications using polyester resin as a binder resin for toner include the following. JP-A-59-7960 discloses (A) alkyl-substituted dicarboxylic acids and/or alkyl-substituted diols, (B) trivalent or higher polycarboxylic acids and/or trivalent or higher polyols, and (C) dicarboxylic acids. ,
(D) A heat-fixable dry toner containing a nonlinear low melting point polyester with an acid value of 10 to 60 obtained from a component containing etherified diphenols is disclosed. Japanese Patent Publication No. 52-25420 (Japanese Unexamined Patent Publication No. 47-12334) discloses a polyester having a pour point lower than 110°C and a sticking point of about 60°C or higher obtained from a dicarboxylic acid and a specific etherified diphenol. A toner containing resin is shown. JP-A No. 59-29256 discloses etherified diphenols that have been propoxylated and/or ethoxylated and have a propoxy group content of 50% or more;
Acid value 10~ obtained by reacting with phthalic acids containing up to 40 mol% of trivalent or higher aromatic carboxylic acids
A toner using 100 amorphous polyester is shown. JP-A-62-45622 discloses non-volatile monocarboxylic acid components, specifically sulfobenzoic acid monoammonium salt, sulfobenzoic acid monosodium salt, cyclohexylaminocarbonylbenzoic acid, n-dodecylaminocarbonylbenzoic acid. A polyester resin containing such as,
Glass transition temperature is 50℃ and softening temperature is 90~
There is a disclosure regarding a polyester resin for toner having a temperature of 170°C. [Problems to be Solved by the Invention] Among the above-mentioned binder resins for polyester resin toners, it can be seen that the binder resins and are limited to negative charging applications because of their high acid values. In the above-mentioned polyester resin, the excess hydroxyl groups are partially blocked with benzoic monocarboxylic acids, but in terms of quantitative ratio, there are quite a large amount of terminal hydroxyl groups that are not blocked. considered to be a thing. According to the research of the present inventors, polyester resins having terminal hydroxyl groups are
It is expected that the amount of negative charge will increase by adding a negative charge control agent, but even if a positive charge control agent is added, the amount of positive charge will remain in a small range, and the problem is that it will not be practical. There is. Further, toners using the above-mentioned polyester resin as a binder resin were not necessarily satisfactory in terms of low temperature fixability and offset resistance. The offset phenomenon is when some of the toner is transferred to the heated roller, staining the surface of the transfer paper that is subsequently fed, or even when the toner is transferred to the pressure roller that is pressed by the heated roller, resulting in transfer problems. This is a phenomenon in which the back side of the paper becomes dirty. In order to solve this problem, the present applicant previously filed a patent application for a toner using a polyester resin modified with rosin as a binder. (Tokugansho
62-184617) However, it became clear that the toner needed to be further improved in terms of positive chargeability, and the inventors of the present invention conducted extensive research. That is, an object of the present invention is to provide a toner composition that has significantly improved positive chargeability while maintaining storage stability, low-temperature fixability, and offset resistance. [Means for Solving the Problems] The present invention provides a polyester resin containing a polybasic acid component, a polyhydric alcohol component, and a disproportionated rosin as condensation components, and a polyester resin having the general formula (However, R ₁ is an alkyl group having 1 to 8 carbon atoms, R ₂ is
R ₃ : Alkyl group having 1 to 18 carbon atoms, R ₄ : C 1
-8 alkyl group or benzyl group) is provided. The present invention will be explained in detail below. The polyester resin used in the present invention is obtained by reacting a polybasic acid component, a polyhydric alcohol, and a disproportionated rosin. Polybasic acid components include terephthalic acid, isophthalic acid, phthalic acid, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, and azelaic acid. , sebacic acid, fumaric acid, maleic acid, itaconic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic 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 and the like. These polybasic acids may be acid anhydrides, esters, chlorides, etc. In addition to dicarboxylic acids, small amounts of trivalent or higher polyvalent carboxylic acids, such as trimellitic acid,
trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4-methylcyclohexane-1,
2,3-tricarboxylic anhydride, trimesic acid,
5-(2,5-dioxotetrahydrofurfuryl)
-3-Methyl-3-cyclohexene-1,2-dicarboxylic anhydride and the like can also be used in combination. Polyhydric alcohol components include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-
pentanediol, 1,6-hexanediol,
1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2,2-dimethyl −
1,3-propanediol (neopentyl glycol), 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-
1,3-propanediol, 3-methyl-1,5
-Pentadiol, 2,2,4-trimethyl-
1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 4 , 4'-thiodiphenol, 4,4'-methylenediphenol, 4,4'-
(2-norbornylidene)diphenol, 4,
4'-dihydroxybiphenol, o-, m- and p-dihydroxybenzene, 4,4'-isopropylidenephenol, 4,4'-isopropylidene bis(2,6-dichlorophenol), 2,5-naphthalenediol , p-xylene diol, cyclopentane-1,2-diol, cyclohexane-1,4-diol, and etherified diphenols such as bisphenol A-alkylene oxide adducts. Depending on the case, a small amount of trihydric or higher polyhydric alcohol can also be used in combination. Examples of the trivalent or higher polyhydric alcohol include glycerin, trimethylolpropane, 1,2,6-hexanetriol, trimethylolethane, pentaerythritol, dipentaerythritol, tripentaerythritol, and sorbitol. Disproportionated rosin is a rosin containing abietic acid as a main component that is heated at high temperature in the presence of a noble metal catalyst or a halogen catalyst to eliminate unstable conjugated double bonds within the molecule. As a main component, it means a mixture of dehydroabietic acid and dihydroabietic acid. The present invention is characterized by the use of such a specific rosin, and even when gum rosin or hydrogenated rosin is used, no significant positive chargeability improvement effect is observed. In short, the polyester resin used in the present invention only needs to contain a polybasic acid component, a polyhydric alcohol component, and a disproportionated rosin as condensation components, and there are no restrictions on its production method, but the following methods are representative. It is true. (a) A polybasic acid and a polyhydric alcohol are charged at once in such a proportion that the latter is in excess, and the disproportionated rosin is also charged. The desired polyester resin is obtained by carrying out an esterification reaction in a conventional manner and then polycondensing in a high vacuum. (b) A normal polyesterification reaction is carried out by charging a polybasic acid and a polyhydric alcohol in such a ratio that the latter is in excess. The disproportionated rosin is then charged and allowed to react with the excess hydroxyl groups, then a monohydric alcohol is added as needed to react with the excess disproportionated rosin, and the excess additional material is then driven off under medium vacuum. , to obtain the desired polyester resin. When carrying out the reactions represented by (a) and (b) above, the proportions of each component and other ingredients should be adjusted so that the acid value of the resulting polyester resin is 4KOHmg/g or less and the hydroxyl value is 20KOHmg/g or less. Preferably, the reaction conditions are defined. If either the acid value or the hydroxyl value exceeds this upper limit, a toner having the expected properties cannot be obtained. A particularly preferable range is
Acid value is 2KOHmg/g or less, hydroxyl value is 12KOH
mg/g or less. Next, the charge control agent used in the present invention has the general formula It is indicated by. Here, R ₁ is an alkyl group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a butyl group,
Amyl group, hexyl group, octyl group, R ₂ ,
R ₃ is an alkyl group having 1 to 18 carbon atoms. _R2 , _R3
In addition to the same as _R1 , specific examples include a decyl group, a dodecyl group, a tetradecyl group, and a hexadecyl group. R ₄ is the same as R ₁ or a benzyl group. As a commercially available product, Bontron P-51 (manufactured by Orient Chemical Industry Co., Ltd.) is well known. Specific examples of the charge control agent represented by the above structural formula include the following. The toner composition is prepared by melt-mixing the above polyester resin, colorant, and charge control agent with additives such as a fluidity improver, a mold release agent, and a plasticizer, if necessary, and then adjusting the mixture to a predetermined particle size. This can be achieved by crushing to Note that other polyester-based or non-polyester-based toner binder resins may be used in combination with the above-mentioned polyester resin as long as the spirit of the present invention is not impaired. Examples of colorants include carbon black,
Nigrosine dye, aniline black, calco oil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow,
Examples include methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, and rose bengal. Among these, carbon black is particularly important. In order to obtain a magnetic toner, a magnetic material that exhibits magnetism but can be magnetized, such as fine powder of metal such as iron, manganese, nickel, cobalt, or chromium, ferrite, permalloy, or the like may be blended into the toner. If necessary, other types of charge control agents can also be used in combination. The proportions of each component in the toner composition of the present invention are 80 to 95 parts by weight of polyester resin, charge control agent,
Suitable amounts are 0.5 to 10 parts by weight, and 5 to 15 parts by weight of the coloring agent. [Function and Effects of the Invention] The toner binder resin of the present invention has a low acid value and a low hydroxyl value because all or most of the hydroxyl groups at the molecular terminals of the polyester polyol are blocked with a disproportionated rosin. It is a substantially neutral resin. The combination of such a resin and a specific charge control agent exhibits excellent positive chargeability that cannot be obtained with other binder resins, gum rosin-modified polyester resins, or hydrogenated rosin-modified polyester resins. [Example] Next, the toner composition of the present invention will be further explained with reference to Examples. Hereinafter, "parts" and "%" are expressed on a weight basis. <Manufacture of binder resin> Example 1 In a flask with a packed tower, 0.9 mol of terephthalic acid,
Ethylene glycol, 0.85 mol, bisphenol A-ethylene oxide adduct 0.5 mol, glycerin 0.1 mol, and disproportionated rosin (Harima Chemical Industry Co., Ltd.)
0.2 mol of Haritaku GX) (manufactured by Haritaku Co., Ltd.) was charged and reacted with n-butyltin oxide as a catalyst at 180 to 250°C with stirring. When distilled water stopped coming out, antimony trioxide was added as a polycondensation catalyst, the packed column was removed, and the
Polycondensation is performed while removing glycol under reduced pressure of Hg,
The reaction was terminated when the distillation of glycol stopped. Example 2 In a flask with a packed tower, 0.9 mol of terephthalic acid,
0.6 mole of ethylene glycol, bisphenol A
- Charge 0.5 mole of ethylene oxide adduct,
180~ using n-butyltin oxide as a catalyst
The reaction was carried out at 250°C with stirring. When distilled water stopped coming out, 2 moles of disproportionated rosin were charged and the reaction was continued for 1 hour, and further 0.3 moles of benzyl alcohol was charged and the reaction was continued for 1 hour.
The packed column was removed, the pressure was reduced to 100 mmHg, unreacted substances were expelled, and the reaction was completed. Comparative Examples 1-2 Hydrogenated rosin (Stabilite Resin manufactured by Rika Hercules) was used instead of disproportionated rosin (Comparative Example 1),
The same reaction as in Example 1 was carried out using gum rosin and gum rosin (Comparative Example 2). Comparative Example 3 In a No. 5 Kolben equipped with a stirrer and a reflux condenser, 1000 g of disproportionated rosin (acid value 162, softening point 79°C) with a purity of 87% (13% is unsaponifiable), 2000 g of epichlorohydrin, and benzyltrimethyl chloride were added. 1 g of ammonium was added and reacted at 80°C for 4 hours. Next, add 160g of granular sodium hydroxide at the same temperature.
was added in portions, the temperature was raised to 100°C, and the reaction was further carried out for 2 hours. After filtering the precipitated salt, unreacted epichlorohydrin was distilled off from the filtrate using a rotary evaporator, and volatile components were completely removed under conditions of 2 mmHg and 120°C to obtain disproportionated rosin glycidyl ester. Next, add 0.9 terephthalic acid to a flask with a packed tower.
0.85 mol of ethylene glycol, 0.5 mol of bisphenol A-ethylene oxide adduct, and 0.2 mol of the above disproportionated rosin glycidyl ester were charged, and reacted with n-butyltin oxide as a catalyst at 180 to 250°C with stirring. . The end point of the reaction was determined when the torque of the stirring motor (400 rpm) reached 2 kg/cm. Table 1 shows the characteristic values of the resins obtained in Examples 1-2 and Comparative Examples 1-3.

[Table] <Preparation and evaluation of toner> The following was prepared as a positive charge control agent. 90 parts of the polyester resin obtained above, 8 parts of carbon black (carbon black #44 manufactured by Mitsubishi Chemical Industries, Ltd.), and 2 parts of a charge control agent were mixed in powder form.
The mixture is supplied to a shaft-type kneader (PCM30 manufactured by Ikegai Iron Works Co., Ltd.) and rotated at a temperature such that the melt viscosity of the above mixture becomes 10,000 to 50,000 poise in the range of 100 to 160°C.
Kneaded at 100 rpm, cooled through a cooling roll, and then milled with a hammer mill to a particle size of 0.8 mm.
It was coarsely ground as below. Next, this powder was finely pulverized at 200 g/hr using a supersonic jet pulverizer equipped with a classifier (LABO JET manufactured by Nippon New Machik Kogyo Co., Ltd.), and then classified using a swirling air classifier, with an average particle size of 5 to 15μ. A toner composition was obtained. The obtained tona composition was prepared as follows.
The stability at 50°C and the amount of charge were investigated. 50℃ storage stability 15g of the toner composition obtained above was put in a 70cc. wide-mouth glass bottle, sealed, and left in a constant temperature bath kept at 50±0.5℃ for 24 hours, then taken out, and the toner fluidity It was visually determined whether or not the data had been preserved. Chargeability 5 parts of the toner composition obtained above and 95 parts of iron powder (TEFV-200/300 manufactured by Nippon Tetsuko Co., Ltd.) were placed in a wide-mouthed glass bottle and stirred for 3 minutes with a rolling mixer (manufactured by Thermal Kagaku Sangyo Co., Ltd.). After that, the amount of charge was measured using a blow-off powder charge amount measuring device (Model TB-200 manufactured by Toshiba Chemical Corporation). Test results The test results of storage stability at 50℃ and charge amount are
Each is shown in the table.

[Table] [Effects] The toner composition of the present invention significantly improves the amount of positive charge.

Claims (1)

[Claims] 1. Polyester resin containing a polybasic acid component, a polyhydric alcohol component, and a disproportionated rosin as condensation components, and general formula (However, R ₁ is an alkyl group having 1 to 8 carbon atoms, R ₂ is
R ₃ : Alkyl group having 1 to 18 carbon atoms, R ₄ : C 1
-8 alkyl group or benzyl group) A toner composition comprising a charge control agent represented by the following formula.