JP6323871B2 - Toner for electrophotography - Google Patents

Description

  The present invention relates to an electrophotographic toner used in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, a binder resin for an electrophotographic toner used in the toner, and a method for producing the same.

  In the field of electrophotography, with the development of electrophotographic systems, development of toner for electrophotography corresponding to high image quality is required.

  For example, Patent Document 1 discloses a maleated rosin compound (a) and a trihydric or higher polyhydric alcohol, which is composed of a dibasic acid component, a polybasic acid component having a trivalent or higher valence, and a polyhydric alcohol component. There is described a binder resin for toner comprising, as a main component, a polyester in which maleated rosin-modified polyhydric alcohol (ab) obtained by reacting with (b) is introduced as a part of the condensation component.

JP-A-4-307557

  Patent Document 1 describes a binder resin for toner that has problems of low-temperature fixability and offset resistance. As a polyhydric alcohol component, 2,2,4,4-tetramethyl-1,3-cyclobutanediol is described. Although it is generally described, its characteristics have not been found.

  The present invention relates to an electrophotographic toner excellent in low-temperature fixability and hot offset resistance, an electrophotographic toner binder resin used for the toner, and a method for producing the same.

  The inventor of the present invention provides an alcohol component containing a specific amount of 2,2,4,4-tetramethyl-1,3-cyclobutanediol and an aliphatic diol having 2 to 6 carbon atoms, and a carboxylic acid component containing an aromatic dicarboxylic acid compound, The polyester obtained by polycondensation was found to be excellent in low-temperature fixability and hot offset resistance, and the present invention was completed.

The present invention
[1] 2,2,4,4-tetramethyl-1,3-cyclobutanediol is contained in an amount of 2 mol% to 70 mol% and an aliphatic diol having 2 to 6 carbon atoms in an amount of 20 mol% to 98 mol%. An electrophotographic toner comprising a polyester obtained by polycondensation of an alcohol component and a carboxylic acid component containing an aromatic dicarboxylic acid compound,
[2] 2,2,4,4-Tetramethyl-1,3-cyclobutanediol 2 mol% to 70 mol% and C2 to 6 mol aliphatic diol 20 mol% to 98 mol% A binder resin for an electrophotographic toner obtained by polycondensation of an alcohol component and a carboxylic acid component containing an aromatic dicarboxylic acid compound, and [3] the binder for an electrophotographic toner according to the above [2] A resin manufacturing method comprising:
Step 1: Polycondensation of an alcohol component containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol and a carboxylic acid component containing an aromatic dicarboxylic acid compound, and Step 2: obtained in Step 1 Mixing the obtained polycondensate, an alcohol component containing an aliphatic diol having 2 or more and 6 or less carbon atoms and a carboxylic acid component containing an aromatic dicarboxylic acid compound, polycondensation, and a step of obtaining a polyester,
The amount of 2,2,4,4-tetramethyl-1,3-cyclobutanediol subjected to Step 1 is the total amount of 2,2,4,4-tetramethyl-1,3-cyclobutanediol subjected to polycondensation. 70 mol% or more,
The amount of the aliphatic diol having 2 to 6 carbon atoms to be subjected to the step 2 is 70 mol% or more in the total amount of the aliphatic diol having 2 to 6 carbon atoms to be subjected to the polycondensation.
The present invention relates to a method for producing a binder resin for an electrophotographic toner.

  The toner for electrophotography of the present invention exhibits excellent effects in low-temperature fixability and hot offset resistance.

The electrophotographic toner of the present invention contains an alcohol component containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol and an aliphatic diol having 2 to 6 carbon atoms, and an aromatic dicarboxylic acid compound. A polyester obtained by polycondensation with a carboxylic acid component is contained as a binder resin.
The reason why the electrophotographic toner of the present invention is excellent in low-temperature fixability and hot offset resistance is not clear, but can be considered as follows.

  2,2,4,4-Tetramethyl-1,3-cyclobutanediol has a cyclic structure with many methyl groups. It is considered that having a large number of methyl groups in this bulky ring structure acts like a wax at the time of fixing, easily peels off the roller, and improves hot offset resistance. Further, the relatively short-chain aliphatic diol having 2 to 6 carbon atoms increases the ester group concentration in the polyester, and at the same time, is excellent in low-temperature fixability. Furthermore, since the glass transition temperature can be increased by including an aromatic dicarboxylic acid compound as a carboxylic acid component, it is considered that the effect of hot offset resistance is more remarkably exhibited.

  As described above, the alcohol component contains 2,2,4,4-tetramethyl-1,3-cyclobutanediol (hereinafter also referred to as TMCD) and an aliphatic diol having 2 to 6 carbon atoms.

  The content of TMCD is 2 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, further preferably 15 mol% or more, and more preferably 18 mol% from the viewpoint of hot offset resistance in the alcohol component. % Or more is more preferable. From the viewpoint of low temperature fixability, it is 70 mol% or less, preferably 60 mol% or less, more preferably 50 mol% or less, further preferably 40 mol% or less, further preferably 33 mol% or less, and 28 mol%. The following is more preferable.

  Examples of the aliphatic diol having 2 to 6 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 1 , 2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 2,3-hexanediol, 3,4-hexanediol, 2,4-hexanediol, 2, Examples include 5-hexanediol and 1,6-hexanediol.

  The carbon number of the aliphatic diol is 2 or more, and preferably 3 or more, from the viewpoint of hot offset resistance. Further, from the viewpoint of low-temperature fixability, it is 6 or less, preferably 5 or less, more preferably 4 or less, and further preferably 3 or less.

  The aliphatic diol having 2 to 6 carbon atoms is preferably an aliphatic diol having a hydroxyl group bonded to a secondary carbon atom from the viewpoint of hot offset resistance and low-temperature fixability. Preferable examples of such aliphatic diols include 1,2-propanediol and 2,3-butanediol.

  The content of the aliphatic diol having 2 to 6 carbon atoms is 20 mol% or more, preferably 25 mol% or more, more preferably 30 mol% or more, and 35 mol% from the viewpoint of low-temperature fixability in the alcohol component. The above is more preferable, and 40 mol% or more is more preferable. Further, from the viewpoint of hot offset resistance, it is 98 mol% or less, preferably 85 mol% or less, more preferably 75 mol% or less, further preferably 65 mol% or less, and further preferably 60 mol% or less.

  The molar ratio of TMCD to aliphatic diol having 2 to 6 carbon atoms (TMCD / aliphatic diol having 2 to 6 carbon atoms) is preferably 5/95 or more, more preferably 10/90 or more, from the viewpoint of hot offset resistance. More preferably, 15/85 or more is more preferable, 20/80 or more is further preferable, and 30/70 or more is further preferable. Further, from the viewpoint of low-temperature fixability, 80/20 or less is preferable, 70/30 or less is more preferable, 60/40 or less is more preferable, 50/50 or less is more preferable, and 40/60 or less is more preferable.

  The alcohol component preferably contains cyclohexanedimethanol (hereinafter also referred to as CHDM) from the viewpoint of low-temperature fixability and transesterification reactivity in Step 2 described later, and contains 1,4-CHDM. More preferably.

  From the viewpoint of hot offset resistance, the molar ratio of TMCD to CHDM (TMCD / CHDM) is preferably 0.3 or more, more preferably 0.5 or more, further preferably 0.7 or more, and further preferably 0.8 or more. Further, from the viewpoint of low-temperature fixability, 4 or less is preferable, 3 or less is more preferable, 2 or less is more preferable, 1.5 or less is further preferable, and 1.3 or less is more preferable.

  The molar ratio of TMCD and CHDM to aliphatic diol having 2 to 6 carbon atoms (TMCD + CHDM / aliphatic diol having 2 to 6 carbon atoms) is preferably 5/95 or more from the viewpoint of hot offset resistance. 10/90 or more is more preferable, 15/85 or more is more preferable, 20/80 or more is more preferable, and 30/70 or more is more preferable. Further, from the viewpoint of low-temperature fixability, 80/20 or less is preferable, 70/30 or less is more preferable, 60/40 or less is more preferable, 50/50 or less is more preferable, and 40/60 or less is more preferable.

  Other alcohol components include aromatic diols such as alkylene oxide adducts of bisphenol A, aliphatic diols having 7 or more carbon atoms, and trivalent or higher alcohols such as glycerin.

  The carboxylic acid component contains an aromatic dicarboxylic acid compound.

  Examples of the aromatic dicarboxylic acid compound include terephthalic acid, isophthalic acid, phthalic acid, furandicarboxylic acid, anhydrides of these acids, esters of these acids with alcohols having 1 to 3 carbon atoms, and the like. Then, from the viewpoint of charge rising property, one kind selected from the group consisting of terephthalic acid, isophthalic acid, furandicarboxylic acid, anhydrides of these acids, and esters of these acids with alcohols having 1 to 3 carbon atoms. The above is preferable, and at least one of terephthalic acid and isophthalic acid is more preferable.

  The content of the aromatic dicarboxylic acid compound is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and 95 mol% in the carboxylic acid component from the viewpoint of the charge rising property of the toner. The following is more preferable.

  Examples of the other carboxylic acid component include trivalent or higher carboxylic acid compounds such as aliphatic dicarboxylic acid compounds and trimellitic acid.

  The alcohol component may contain a monovalent alcohol, and the carboxylic acid component may contain a monovalent carboxylic acid compound as appropriate.

The polyester contained in the toner of the present invention as a binder resin is obtained by polycondensing an alcohol component and a carboxylic acid component as raw material monomers. The raw material monomer may be subjected to polycondensation at one time, or may be divided and subjected to polycondensation, and polycondensation may be performed in multiple stages.
Step 1: Polycondensation of an alcohol component containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol and a carboxylic acid component containing an aromatic dicarboxylic acid compound, and Step 2: obtained in Step 1 The polyester is obtained by a method comprising a step of mixing the obtained polycondensate, an alcohol component containing an aliphatic diol having 2 to 6 carbon atoms and a carboxylic acid component containing an aromatic dicarboxylic acid compound, and polycondensing to obtain a polyester. It is preferable to manufacture.

  By the above method, TMCD and aliphatic diol having 2 to 6 carbon atoms can be uniformly polycondensed, and hot offset resistance and low-temperature fixability are further improved. This is because TMCD has a steric hindrance so that the polycondensation reaction is slow. When an aliphatic diol having 2 to 6 carbon atoms and TMCD are simultaneously polycondensed, an aliphatic having 2 to 6 carbon atoms that has a fast polycondensation reaction. Since the diol reacts first and the slow-reacting TMCD reacts later, the aliphatic diol site and the TMCD site exist separately, and the effect of both may not be fully demonstrated. It is done. On the other hand, in the above method, TMCD and the aliphatic diol having 2 to 6 carbon atoms are more uniformly distributed by transesterifying the aliphatic diol having 2 to 6 carbon atoms after first reacting TMCD. Therefore, it is thought that the effect is excellent.

  Therefore, it is preferable to use TMCD in Step 1 and an aliphatic diol having 2 to 6 carbon atoms in Step 2. From this point of view, the amount of TMCD used in Step 1 is preferably 70 mol% or more, more preferably 90 mol% or more, still more preferably 100 mol%, more preferably 100 mol%, based on the total amount of TMCD used for polycondensation. Is more preferable. Similarly, the amount of the aliphatic diol having 2 to 6 carbon atoms to be used in Step 2 is preferably 70 mol% or more, and more than 90 mol% in the total amount of the aliphatic diol having 2 to 6 carbon atoms to be subjected to polycondensation. Is more preferable, substantially 100 mol% is further preferable, and 100 mol% is further more preferable.

  From the viewpoint of low-temperature fixability and from the viewpoint of polycondensation while transesterifying the aliphatic diol in Step 2, cyclohexanedimethanol is preferably used in Step 1 as the alcohol component. The amount of CHDM used in Step 1 is preferably 70 mol% or more, more preferably 90 mol% or more, still more preferably 100 mol%, and even more preferably 100 mol%, based on the total amount of CHDM used for polycondensation.

  From these viewpoints, the content of TMCD in the alcohol component to be subjected to the polycondensation in Step 1 is preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, preferably 80 The mol% or less, more preferably 70 mol% or less, still more preferably 60 mol% or less. The CHDM content is preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, preferably 80 mol% or less, more preferably 70 mol% or less, still more preferably Is 60 mol% or less.

The aromatic dicarboxylic acid compounds used in Step 1 and Step 2 may be the same or different. However, since TMCD is solid, the aromatic dicarboxylic acid compound used in Step 1 is a heavy compound from the viewpoint of reactivity. An ester of an aromatic dicarboxylic acid and an alcohol having 1 to 3 carbon atoms which is liquid at the condensation reaction temperature is preferable.
The aromatic dicarboxylic acid compound used in Step 2 is at least one selected from the group consisting of aromatic dicarboxylic acids, anhydrides of these acids, and esters of these acids and alcohols having 1 to 3 carbon atoms. It is preferable.

  From the viewpoint of low-temperature fixability, the molar ratio of the aromatic dicarboxylic acid compound to be used in Step 1 to the aromatic dicarboxylic acid compound to be used in Step 2 (Step 1 / Step 2) is preferably 5/95 or more, and 15/85 or more. More preferred is 35/65 or more. Further, from the viewpoint of hot offset resistance, it is preferably 80/20 or less, more preferably 60/60 or less, and further preferably 45/55 or less.

  In addition, when using a trivalent or higher raw material monomer such as a trivalent or higher carboxylic acid compound or a trivalent or higher alcohol, the trivalent or higher raw material monomer is used from the viewpoint of reacting an aliphatic diol while transesterifying in Step 2. , Preferably after step 2 or step 2. From this viewpoint, the content of the diol in the alcohol component used in Step 1 is preferably 80 mol% or more, more preferably 95 mol% or more, substantially more preferably 100 mol%, still more preferably 100 mol%. Similarly, in the carboxylic acid compound used in Step 1, the content of the dicarboxylic acid compound is preferably 80 mol% or more, more preferably 95 mol% or more, substantially more preferably 100 mol%, further preferably 100 mol%. Is more preferable.

  From the viewpoint of polycondensation reactivity, the molar ratio of the alcohol component to the carboxylic acid component (alcohol component / carboxylic acid component) used in Step 1 is preferably 0.8 or more, more preferably 1.05 or more, and even more preferably 1.10 or more. Further, from the viewpoint of hot offset resistance, 1.5 or less is preferable, and 1.3 or less is more preferable.

From the viewpoint of hot offset resistance, the polycondensation reaction rate in step 1 is
[100-X]% or more (provided that X = content of 2,2,4,4-tetramethyl-1,3-cyclobutanediol in the alcohol component used in Step 1 (mol%))
It is preferable to perform step 2 at this point. Here, the reaction rate of the polycondensation in the step 1 is the reaction rate of a component with a small number of moles in the total alcohol component or the total carboxylic acid component subjected to the polycondensation in the step 1, or the same number of moles of both components. In this case, the reaction rate is the value of the reaction rate of either one of the components. When the carboxylic acid component is a carboxylic acid or an anhydride, the reaction water amount / theoretical product water amount × 100 or the carboxylic acid component In the case of an ester, it can be determined by the value of dealcoholization amount / theoretical dealcoholation amount × 100.
From the viewpoint of hot offset resistance, the polycondensation reaction rate in step 1 when performing step 2 is more preferably [100-X / 1.5]% or more, and more preferably [100-X / 2]% or more. [100-X / 3]% or more is more preferable. The specific reaction rate is preferably 50% or more, more preferably 60% or more, further preferably 70% or more, further preferably 80% or more, and further preferably 90% or more.

  The molar ratio (TMCD / aliphatic diol having 2 to 6 carbon atoms) of TMCD used for Step 1 and aliphatic diol having 2 to 6 carbon atoms used for Step 2 is 5/95 or more from the viewpoint of hot offset resistance. Preferably, 10/90 or more is more preferable, 15/85 or more is more preferable, 20/80 or more is more preferable, and 30/70 or more is more preferable. Further, from the viewpoint of low-temperature fixability, 80/20 or less is preferable, 70/30 or less is more preferable, 60/40 or less is more preferable, 50/50 or less is more preferable, and 40/60 or less is more preferable.

  From the viewpoint of polycondensation reactivity, the molar ratio of the alcohol component to the carboxylic acid component used in step 2 (alcohol component / carboxylic acid component) is preferably 1.2 or less, more preferably 1.00 or less, still more preferably 0.98 or less, and 0.95 The following is more preferable. Further, from the viewpoint of hot offset resistance, 0.80 or more is preferable, 0.85 or more is more preferable, and 0.88 or more is more preferable.

  The end point of the reaction in Step 2 is the reaction rate of a small number of moles of all alcohol components or all carboxylic acid components subjected to polycondensation through Step 1 and Step 2, or when both components have the same number of moles, The reaction rate of either one of the components is preferably 90% or more, more preferably 93% or more, and preferably 99% or less from the viewpoint of productivity. The reaction rate of the polycondensation in step 2 can be determined in the same manner as in step 1.

  In Step 1, the temperature during the polycondensation reaction of the alcohol component and the carboxylic acid component is preferably 130 ° C. or higher, more preferably 150 ° C. or higher from the viewpoint of reactivity, and 220 ° C. or lower from the viewpoint of thermal decomposition of TMCD. Preferably, it is 210 ° C. or lower. In Step 2, from the viewpoint of reactivity, 170 ° C. or higher is preferable, 180 ° C. or higher is more preferable, and from the viewpoint of thermal decomposability of the resulting polyester, 250 ° C. or lower is preferable, and 240 ° C. or lower is more preferable.

  The polycondensation reaction may be performed in the presence of an esterification catalyst, an esterification cocatalyst, a polymerization inhibitor, or the like, if necessary.

  Examples of esterification catalysts include tin catalysts and titanium catalysts. Examples of the tin catalyst include dibutyltin oxide and tin (II) 2-ethylhexanoate. From the viewpoints of reactivity, molecular weight adjustment and resin physical property adjustment, Sn such as tin (II) 2-ethylhexanoate is used. Tin (II) compounds having no —C bond are preferred. Examples of the titanium catalyst include titanium diisopropylate bistriethanolamate. The amount of the esterification catalyst used is preferably 0.01 to 1.5 parts by mass, more preferably 0.1 to 1.0 part by mass with respect to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

  When the polycondensation reaction is carried out in two steps, the esterification catalyst is added to the reaction system in a divided manner in consideration of the amount of raw material monomer used in each step even if it is added at once in the first step (step 1). May be.

  The softening point of the polyester is preferably 90 ° C. or higher, more preferably 100 ° C. or higher, and further preferably 105 ° C. or higher, from the viewpoint of low-temperature fixability. From the viewpoint of hot offset resistance, it is preferably 130 ° C. or lower, more preferably 125 ° C. or lower, further preferably 120 ° C. or lower, and further preferably 115 ° C. or lower.

  The glass transition temperature of the polyester is preferably 53 ° C. or higher, more preferably 55 ° C. or higher, and further preferably 58 ° C. or higher from the viewpoint of hot offset resistance and storage stability. Further, from the viewpoint of low-temperature fixability, it is preferably 68 ° C. or lower, more preferably 65 ° C. or lower, and further preferably 63 ° C. or lower.

  The acid value of the polyester is preferably 3 mgKOH / g or more, more preferably 5 mgKOH / g or more, further preferably 10 mgKOH / g or more, and further preferably 15 mgKOH / g or more, from the viewpoint of low-temperature fixability. From the viewpoint of hot offset resistance, it is preferably 40 mgKOH / g or less, more preferably 35 mgKOH / g or less, further preferably 30 mgKOH / g or less, and further preferably 25 mgKOH / g or less.

  The number average molecular weight of the polyester is preferably 1000 or more, more preferably 1500 or more, and further preferably 1800 or more from the viewpoint of hot offset resistance and durability. Further, from the viewpoint of low-temperature fixability, it is preferably 4000 or less, more preferably 3000 or less, further preferably 2800 or less, and further preferably 2500 or less.

  In the toner of the present invention, a known resin other than the polyester may be used in combination as a binder resin as long as the effects of the present invention are not impaired. The content of the polyester is 90% in the binder resin. -100 mass% is preferable, 93-100 mass% is more preferable, 95-100 mass% is further more preferable.

  The toner of the present invention includes a colorant, a release agent, a charge control agent, magnetic powder, a fluidity improver, a conductivity modifier, a reinforcing filler such as a fibrous substance, an antioxidant, and a cleaning property improver. Additives may be contained, and it is preferable that a colorant, a release agent and a charge control agent are contained.

  As the colorant, all of dyes and pigments used as toner colorants can be used, such as carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, Solvent Red 49, Solvent Red 146, Solvent Blue 35, Quinacridone, Carmine 6B, Disazo Yellow and the like can be used, and the toner of the present invention may be either a black toner or a color toner. The content of the colorant is preferably 1 part by mass or more and more preferably 2 parts by mass or more with respect to 100 parts by mass of the binder resin from the viewpoint of improving the toner image density and low-temperature fixability. Moreover, 40 mass parts or less are preferable, and 10 mass parts or less are more preferable.

  Examples of mold release agents include polypropylene wax, polyethylene wax, polypropylene polyethylene copolymer wax, aliphatic hydrocarbon wax such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax, and oxides thereof, carnauba wax, montan wax, Sazol wax and ester waxes such as those deoxidized waxes, fatty acid ester waxes, fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts, etc. may be mentioned, and these may be used alone or in combination of two or more. Can be used.

  The melting point of the release agent is preferably 60 to 160 ° C., more preferably 60 to 150 ° C., from the viewpoints of low-temperature fixability and offset resistance of the toner.

  The content of the release agent is preferably 0.5 parts by mass or more with respect to 100 parts by mass of the binder resin from the viewpoint of low-temperature fixability and offset resistance of the toner and dispersibility in the binder resin. More preferably, it is more preferably 1.5 parts by mass or more. Moreover, 10 mass parts or less are preferable, 8 mass parts or less are more preferable, and 7 mass parts or less are further more preferable.

  The charge control agent is not particularly limited, and may contain either a positively chargeable charge control agent or a negatively chargeable charge control agent.

  Examples of positively chargeable charge control agents include nigrosine dyes such as “Nigrosine Base EX”, “Oil Black BS”, “Oil Black SO”, “Bontron N-01”, “Bontron N-04”, “Bontron N-07 ”,“ Bontron N-09 ”,“ Bontron N-11 ”(manufactured by Orient Chemical Co., Ltd.), etc .; triphenylmethane dyes containing tertiary amines as side chains, quaternary ammonium salt compounds such as“ Bontron ” P-51 "(manufactured by Orient Chemical Industries), cetyltrimethylammonium bromide," COPY CHARGE PX VP435 "(manufactured by Clariant), etc .; polyamine resins such as" AFP-B "(manufactured by Orient Chemical Industries); imidazole derivatives Examples thereof include “PLZ-2001”, “PLZ-8001” (manufactured by Shikoku Kasei Co., Ltd.) and the like; styrene-acrylic resins such as “FCA-701PT” (manufactured by Fujikura Kasei Co., Ltd.) and the like.

  Further, as the negatively chargeable charge control agent, metal-containing azo dyes such as “Varifast Black 3804”, “Bontron S-31”, “Bontron S-32”, “Bontron S-34”, “Bontron S-36” (Above, manufactured by Orient Chemical Co., Ltd.), “Eisenspiron Black TRH”, “T-77” (manufactured by Hodogaya Chemical Co., Ltd.), etc .; metal compounds of benzylic acid compounds such as “LR-147”, “ LR-297 "(manufactured by Nippon Carlit Co., Ltd.) and the like; metal compounds of salicylic acid compounds such as" Bontron E-81 "," Bontron E-84 "," Bontron E-88 "," Bontron E-304 "( Above, manufactured by Orient Chemical Co., Ltd.), “TN-105” (manufactured by Hodogaya Chemical Co., Ltd.), etc .; copper phthalocyanine dyes; quaternary ammonium salts such as “COPY CHARGE NX VP434” (manufactured by Clariant), nitroimidazole derivatives Organic metal compounds such as “TN105” (Hodogaya Chemical Company, Ltd.), and the like.

  The content of the charge control agent is preferably 0.01 parts by mass or more and more preferably 0.2 parts by mass or more with respect to 100 parts by mass of the binder resin from the viewpoint of the charging stability of the toner. Further, it is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, further preferably 3 parts by mass or less, and further preferably 2 parts by mass or less.

  The toner of the present invention may be a toner obtained by any conventionally known method such as a melt-kneading method, an emulsion phase inversion method, or a polymerization method, but from the viewpoint of productivity and dispersibility of the colorant, A pulverized toner obtained by a melt kneading method is preferred. In the case of pulverized toner by the melt-kneading method, for example, after a raw material such as a binder resin, a colorant, a release agent, and a charge control agent is uniformly mixed with a mixer such as a Henschel mixer, a hermetically sealed kneader, uniaxial or 2 It can be manufactured by melt-kneading with a shaft extruder, open roll type kneader or the like, cooling, pulverizing and classifying.

  In the toner of the present invention, an external additive is preferably used in order to improve transferability, and inorganic fine particles are preferably used as the external additive. Examples of the inorganic fine particles include silica, alumina, titania, zirconia, tin oxide, zinc oxide and the like, and silica is preferable.

  Silica is preferably hydrophobic silica that has been subjected to a hydrophobic treatment, from the viewpoint of toner transferability.

  Examples of the hydrophobizing agent for hydrophobizing the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), silicone oil, octyltriethoxysilane (OTES), and methyltriethoxysilane. It is done.

  The average particle diameter of the external additive is preferably 10 nm or more, and more preferably 15 nm or more, from the viewpoint of the chargeability, fluidity, and transferability of the toner. Further, it is preferably 250 nm or less, more preferably 200 nm or less, and further preferably 90 nm or less.

  The content of the external additive is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and further preferably 0.3 parts by mass or more with respect to 100 parts by mass of the toner before being processed with the external additive. Moreover, 5 mass parts or less are preferable, and 3 mass parts or less are more preferable.

The volume median particle size (D ₅₀ ) of the toner of the present invention is preferably from 3 to 15 μm, more preferably from 4 to 10 μm. In the present specification, the volume-median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size. When the toner is treated with an external additive, the volume median particle size of the toner particles before being treated with the external additive is defined as the volume median particle size of the toner.

  The toner of the present invention can be used as a one-component developing toner or as a two-component developer mixed with a carrier.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The physical properties of the resin and the like were measured by the following method.

[Softening point of resin]
Using a flow tester “CFT-500D” (manufactured by Shimadzu Corporation), a 1 g sample was heated at a heating rate of 6 ° C./min, a 1.96 MPa load was applied by a plunger, a nozzle with a diameter of 1 mm and a length of 1 mm Extrude from. The amount of plunger drop of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening point.

[Glass transition temperature of resin]
Using a differential scanning calorimeter “DSC210” (manufactured by Seiko Denshi Kogyo Co., Ltd.), 0.01 to 0.02 g of sample is weighed into an aluminum pan, heated to 200 ° C, and from that temperature to 0 ° C at a cooling rate of 10 ° C / min. Cooling. Next, the sample is heated at a heating rate of 10 ° C / min, and the temperature at the intersection of the base line extension below the endothermic peak temperature and the tangent that indicates the maximum slope from the peak rise to the peak apex is measured. The glass transition temperature is assumed.

[Acid value of the resin]
Measured according to the method of JIS K0070. However, only the measurement solvent is changed from the mixed solvent of ethanol and ether specified in JIS K0070 to the mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Number average molecular weight of resin]
The molecular weight distribution is measured by the gel permeation chromatography (GPC) method according to the following method to determine the number average molecular weight.
(1) Preparation of sample solution Dissolve the sample in tetrahydrofuran at 25 ° C so that the concentration is 0.5 g / 100 ml. Next, this solution is filtered using a fluororesin filter “DISMIC-25JP” (manufactured by ADVANTEC) having a pore size of 0.2 μm to remove insoluble components to obtain a sample solution.
(2) Molecular weight measurement Using the following measuring device and analytical column, tetrahydrofuran is flowed as an eluent at a flow rate of 1 ml / min, and the column is stabilized in a constant temperature bath at 40 ° C. Measurement is performed by injecting 100 μl of the sample solution. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. At this time, several types of monodisperse polystyrene (A-500 (5.0 × 10 ² ), A-1000 (1.01 × 10 ³ ), A-2500 (2.63 × 10 ³ ), A- 5000 (5.97 × 10 ³ ), F-1 (1.02 × 10 ⁴ ), F-2 (1.81 × 10 ⁴ ), F-4 (3.97 × 10 ⁴ ), F-10 (9.64 × 10 ⁴ ), F- 20 (1.90 × 10 ⁵ ), F-40 (4.27 × 10 ⁵ ), F-80 (7.06 × 10 ⁵ ), F-128 (1.09 × 10 ⁶ )) prepared as standard samples are used.
Measuring device: HLC-8220GPC (manufactured by Tosoh Corporation)
Analytical column: GMHXL + G3000HXL (manufactured by Tosoh Corporation)

[Melting point of release agent]
Using a differential scanning calorimeter “DSC210” (manufactured by Seiko Denshi Kogyo Co., Ltd.), 0.01 to 0.02 g of sample is weighed into an aluminum pan, heated to 200 ° C, and from that temperature to 0 ° C at a cooling rate of 10 ° C / min. Cooling. Next, the sample is heated at a heating rate of 10 ° C./min, and the maximum peak temperature of the heat of fusion is taken as the melting point.

[Average particle diameter of external additive]
The volume average particle diameter of the primary particles is obtained from the following formula.
Average particle diameter (nm) = 6 / (ρ × specific surface area (m ² / g)) × 1000
In the formula, ρ is the true specific gravity of the external additive. For example, the true specific gravity of silica is 2.2. The specific surface area is a BET specific surface area determined by a nitrogen adsorption method. The above formula is assumed to be a sphere having a particle size R,
Specific surface area = S x (1 / m)
m (weight of particle) = 4/3 x π x (R / 2) ³ x true specific gravity
S (surface area) = 4π (R / 2) ²
Is an expression obtained from

[Volume-median particle diameter of toner (D ₅₀ )]
Measuring machine: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 50μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
Electrolyte: Isoton II (Beckman Coulter, Inc.)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) 5% electrolyte dispersion condition: 10 mg of measurement sample is added to 5 ml of dispersion, and dispersed for 1 minute with an ultrasonic disperser. Then, 25 ml of the electrolytic solution is added, and further dispersed with an ultrasonic disperser for 1 minute.
Measurement conditions: Add 100 ml of electrolyte and dispersion in a beaker, measure 30,000 particles at a concentration that can measure the particle size of 30,000 particles in 20 seconds, and determine the volume-median particle size ( determine the D _50).

[Manufacture of binder resin]
Resin Production Example 1 [Resin 1-13]
<Step 1>
2,1,4,4-Tetramethyl-1,3-cyclobutanediol (TMCD) and 1,4-cyclohexanedimethanol (CHDM), dimethyl terephthalate and esterification catalyst (2-ethylhexane) shown in Tables 1 and 2 In a 10-liter four-necked flask equipped with a thermometer, stainless steel stirrer, fractionation tower, dehydration tube, cooling tube, and nitrogen inlet tube in a mantle heater under a nitrogen atmosphere The reaction rate was raised to 150 ° C and the temperature was raised stepwise for 5 hours. After confirming that the reaction rates shown in Tables 1 and 2 were reached at 200 ° C, 1 hour at 13.3kPa A reduced pressure reaction was performed to obtain a polyester.

<Process 2>
To the obtained polyester in the four-necked flask, 1,2-propanediol or 1,3-propanediol shown in Tables 1 and 2 and terephthalic acid were added, and in a mantle heater in a nitrogen atmosphere, 180 to After raising the temperature stepwise to 220 ° C and reacting for 5 hours, it was confirmed that the reaction rate reached 95% at 220 ° C. Polyesters with softening points shown in Tables 1 and 2 at 13.3kPa were obtained. Obtained.

Resin production example 2 [resins 14 to 16]
10 liters equipped with a raw material monomer and esterification catalyst (tin (2-ethylhexanoate) tin)) shown in Table 2 equipped with a thermometer, a stainless steel stirring rod, a fractionating column, a dehydrating tube, a cooling tube, and a nitrogen introducing tube Was heated to 185 ° C in a mantle heater in a nitrogen atmosphere, reacted for 3 hours, and then gradually heated to 220 ° C at a rate of 5 ° C / h. . After confirming that the reaction rate reached 95% at 220 ° C, the reaction was continued until the softening point shown in Table 2 was reached while distilling off the alcohol component of the raw material monomer at 5.3 kPa to obtain a polyester. It was.

[Manufacture of toner for electrophotography]
Examples 1 to 14 and Comparative Examples 1 and 2
100 parts by weight of binder resin shown in Table 3, 5 parts by weight of colorant “Regal 330R” (Cabot, carbon black), 1 part of negative charge control agent “Bontron E-81” (manufactured by Orient Chemical Industries) And 2 parts by weight of release agent “Mitsui High Wax NP055” (manufactured by Mitsui Chemicals, Polypropylene wax, melting point: 125 ° C.) are thoroughly mixed with a Henschel mixer, and then rotated using a co-rotating twin-screw extruder. Melt kneading was performed at a speed of 200 r / min and a heating temperature of 80 ° C. in the roll. The obtained melt-kneaded product was cooled and coarsely pulverized, then pulverized with a jet mill and classified to obtain toner particles having a volume median particle size (D ₅₀ ) of 8 μm.

  To 100 parts by mass of the toner particles obtained, 1.0 part by mass of hydrophobic silica “NAX-50” (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: HMDS, average particle size: 30 nm) is added and mixed with a Henschel mixer. Thus, a toner was obtained.

Test Example 1 [low temperature fixability]
Toner was installed in a machine that improved the fixing machine of the copier “AR-505” (manufactured by Sharp Corporation) so that it can be fixed outside the machine, and paper manufactured by Sharp Corporation [CopyBond SF-70NA ( 75 g / m ² )] was obtained in an unfixed state. Using a fixing machine (fixing speed 390mm / sec) adjusted so that the total fixing pressure is 40kgf, the fixing roller temperature is increased from 100 ° C to 240 ° C in 10 ° C increments, and the unfixed state at each temperature. The fixing test of the printed material was conducted. “UNICEF Cellophane” (Mitsubishi Pencil Co., Ltd., width: 18 mm, JISZ-1522) was attached to the fixed image, passed through a fixing roller set at 30 ° C., and then the tape was peeled off. The optical reflection density before and after the tape was peeled off was measured using a reflection densitometer “RD-915” (manufactured by Macbeth), and the ratio between the two (after peeling / before sticking × 100) was initially 90%. The temperature of the fixing roller that exceeded the minimum fixing temperature. The results are shown in Table 3. The lower the minimum fixing temperature, the better the low-temperature fixing property. The minimum fixing temperature is preferably 140 ° C. or lower, more preferably 120 ° C. or lower, and even more preferably 110 ° C. or lower.

Test Example 2 [Hot offset resistance]
In Test Example 1, after image formation was performed at each fixing temperature, the blank transfer paper was continuously fed to the fixing roller under the same conditions, and the temperature of the fixing roller at which toner contamination first occurred on the white paper was hot-offset. It was set as the generation temperature. The results are shown in Table 3. The higher the hot offset generation temperature, the better the hot offset resistance. The hot offset generation temperature is preferably 155 ° C. or higher, more preferably 175 ° C. or higher, and further preferably 185 ° C. or higher.

It can be seen that the toners of Examples 1 to 14 are excellent in both the low-temperature fixability and the offset resistance as compared with the toners of Comparative Examples 1 and 2.
In comparison with this, the toner of Comparative Example 1 containing a polyester having no C 2-6 aliphatic diol as a binder resin has insufficient low-temperature fixability and binds a polyester not using TMCD. The toner of Comparative Example 2 contained as a resin is insufficient in hot offset resistance.
Moreover, the following can be understood from the comparison of the examples.
From the comparison of Examples 1 to 3, in the production of polyester, the higher the reaction rate in Step 1, the more remarkable the improvement in hot offset resistance.
As compared with Examples 1 and 4 to 9, the higher the content of TMCD in the alcohol component of the polyester, the higher the hot offset resistance, and the higher the content of the aliphatic diol having 2 to 6 carbon atoms, the lower the temperature fixing. Improves.
From the comparison between Examples 9 and 10, as the aliphatic diol having 2 to 6 carbon atoms, the aliphatic diol having a hydroxyl group bonded to a secondary carbon atom is lower in temperature fixing than the α, ω-aliphatic diol. It is effective in improving the hot offset resistance.
From the comparison of Examples 9 and 11, as an aromatic dicarboxylic acid compound, terephthalic acid is more effective in improving hot offset resistance than isophthalic acid or furandicarboxylic acid.
From the comparison of Examples 1 and 13, it can be seen that the use of CHDM improves the low-temperature fixability.
From the comparison between Examples 1 and 14, in the polycondensation of the alcohol component and the carboxylic acid component, the TMCD was reacted in advance, and then the aliphatic diol having 2 to 6 carbon atoms was reacted, thereby allowing low temperature fixability and offset resistance. Both improve.

  The electrophotographic toner of the present invention is suitably used as a toner used for developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method and the like.

Claims (3)

  Alcohol component containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol in an amount of 2 mol% to 70 mol% and an aliphatic diol having 2 to 6 carbon atoms in an amount of 20 mol% to 98 mol% And an electrophotographic toner comprising a polyester obtained by polycondensation of a carboxylic acid component containing an aromatic dicarboxylic acid compound.   Molar ratio of 2,2,4,4-tetramethyl-1,3-cyclobutanediol to aliphatic diol having 2 to 6 carbon atoms (2,2,4,4-tetramethyl-1,3-cyclobutanediol / The toner for electrophotography according to claim 1, wherein the aliphatic diol having 2 to 6 carbon atoms is 5/95 or more and 80/20 or less.   The aromatic dicarboxylic acid compound is one or more selected from the group consisting of terephthalic acid, isophthalic acid, furandicarboxylic acid, anhydrides of these acids, and esters of these acids with alcohols having 1 to 3 carbon atoms The toner for electrophotography according to claim 1 or 2.