JP2011132333A - Method for producing crystalline polyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystalline polyester having small variation of grindability, to provide a method for stably producing the crystalline polyester and to provide a method for producing a toner using the crystalline polyester. <P>SOLUTION: The method for producing the crystalline polyester includes a step 1 for performing condensation polymerization of an alcoholic component containing a 2-8C α,ω-straight chain aliphatic diol and a carboxylic acid component containing an unsaturated aliphatic dicarboxylic acid compound and a step 2 for obtaining the crystalline polyester by adding at least one selected from a compound having a catechol skeleton and a compound having a hydroquinone skeleton and a radical polymerization initiator during the condensation polymerization or after condensation polymerization in the step 1. The crystalline polyester obtained by the method is also provided. The method for producing the toner includes a step for melting and kneading a toner raw material containing the crystalline polyester and an amorphous polyester and crushing the obtained melted and kneaded product. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a crystalline polyester used as a binder resin for an electrophotographic toner used in electrophotography, electrostatic recording method, electrostatic printing method, etc., a method for producing the same, and a toner using the crystalline polyester It relates to the manufacturing method.

  In recent years, crystalline polyesters have a low melt temperature due to the sharp melt property that the crystalline part develops, the high compatibility with amorphous polyesters unlike other crystalline resins such as polyethylene, and the ease of dispersion. It is attracting attention as a binder resin suitable for improving the fixability.

  Patent Document 1 includes a binder resin and a colorant for the purpose of providing a toner for electrophotography that is spherical, has excellent fixability at low temperatures, and has good offset resistance in a wide temperature range. In the electrophotographic toner, an electrophotographic toner is disclosed, wherein the binder resin contains a crystalline polyester having a crosslinked structure with an unsaturated site as a main component, and toner particles are spherical. .

JP 2001-117268 A

  In order to improve the durability of the toner, it is necessary to grind the binder resin. Generally, however, the crystalline polyester has a crystalline portion compared to the amorphous polyester. Therefore, it is inferior in grindability and easily contaminates members such as a grinder. Further, even if the pulverizability is improved, if the stable pulverizable crystalline polyester cannot be produced, there is a problem that the production efficiency of the toner is lowered.

  An object of the present invention is to provide a crystalline polyester having a small change in grindability, a method for stably producing the crystalline polyester, and a method for producing a toner using the crystalline polyester.

The present invention
[1] Step 1: Steps of polycondensing an alcohol component containing an α, ω-linear aliphatic diol having 2 to 8 carbon atoms and a carboxylic acid component containing an unsaturated aliphatic dicarboxylic acid compound, and a step 2: including a step of obtaining a crystalline polyester by adding one or more selected from a compound having a catechol skeleton and a compound having a hydroquinone skeleton and a radical polymerization initiator during or after the condensation polymerization reaction in Step 1 , Method for producing crystalline polyester,
[2] A crystalline polyester obtained by the method described in [1] above, and [3] a toner material containing the crystalline polyester and amorphous polyester described in [2] above obtained by melt-kneading The present invention relates to a toner manufacturing method including a step of pulverizing a melt-kneaded product.

  According to the method of the present invention, a crystalline polyester having a small change in grindability can be produced stably.

  In producing crystalline polyester, the present inventors improved the grindability by using an unsaturated aliphatic dicarboxylic acid compound as the carboxylic acid component and increasing the molecular weight of a portion of the polyester with a radical polymerization initiator. It was found that the obtained crystalline polyester was obtained. This is because when the crystalline polyester is crystallized, the crystal growth rate is different between the high molecular weight part and the other part, so micro distortion occurs in the crystalline resin, which improves the grindability of the crystalline polyester. It is thought that it contributes to. However, since the melting point of the crystalline polyester is usually about 100 ° C., it is necessary to add the radical polymerization initiator at a higher temperature than that, but the reactivity becomes very high. The pulverizability of the crystalline polyester changes. Therefore, it has been difficult to produce a crystalline polyester having stable pulverization performance.

  Therefore, as a result of further studies by the present inventors, at least one selected from a compound having a catechol skeleton and a compound having a hydroquinone skeleton was added before and after the radical polymerization initiator, preferably before the addition of the radical polymerization initiator. It has been found that if added to the reaction system, the activity of the radical polymerization initiator can be lowered to some extent, and a crystalline polyester having a small change in grindability can be stably produced.

From the above viewpoint, in the present invention,
Step 1: Step of polycondensing an alcohol component containing an α, ω-linear aliphatic diol having 2 to 8 carbon atoms and a carboxylic acid component containing an unsaturated aliphatic dicarboxylic acid compound, and Step 2: Step 1 or more selected from a compound having a catechol skeleton and a compound having a hydroquinone skeleton and a radical polymerization initiator during or after the polycondensation reaction of 1 to obtain a crystalline polyester, To produce reactive polyester.

  The crystallinity of polyester is expressed as the ratio between the softening point and the highest endothermic peak temperature measured by a differential scanning calorimeter, that is, the softening point / the highest endothermic peak temperature. Generally, when this value exceeds 1.4, the resin is amorphous. When the ratio is less than 0.6, the crystallinity is low and there are many amorphous parts. The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate) and the like. In the present invention, “crystalline polyester” means a polyester having a maximum softening point / endothermic peak temperature value of 0.6 to 1.4, preferably 0.8 to 1.2, and “amorphous polyester” means a softening point / A polyester having a maximum peak temperature value of endotherm of greater than 1.4 or less than 0.6, preferably greater than 1.4. The highest endothermic peak temperature refers to the temperature of the peak on the highest temperature side among the observed endothermic peaks. If the maximum peak temperature is within ± 20 ° C of the softening point, the peak temperature is taken as the melting point, and a peak whose difference from the softening point exceeds 20 ° C is a peak resulting from the glass transition. In the present invention, the term “polyester” means both crystalline polyester and amorphous polyester.

  As the alcohol component, an α, ω-linear aliphatic diol having 2 to 8 carbon atoms is contained from the viewpoint of enhancing the crystallinity and grindability of the crystalline polyester.

  Examples of the α, ω-linear aliphatic diol having 2 to 8 carbon atoms include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and the like. 4-8 are preferable and 4-6 are more preferable.

  The content of the α, ω-linear aliphatic diol is preferably 70 to 100 mol%, more preferably 90 to 100 mol%, and still more preferably 95 to 100 mol% in the alcohol component.

  Examples of the trihydric or higher polyhydric alcohol component include glycerin and trimethylolpropane.

  From the viewpoint of grindability of the crystalline polyester, the alcohol component does not contain a trihydric or higher polyhydric alcohol component, or even if it is contained, the content is preferably 5 mol% or less, preferably 3 mol% or less. More preferred is 1 mol% or less.

  The unsaturated aliphatic dicarboxylic acid compound is preferably a dicarboxylic acid compound such as maleic acid, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, anhydrides of these acids, and alkyl (carbon number 1 to 3) esters. Among these, from the viewpoint of crystallinity, at least one selected from the group consisting of fumaric acid, maleic acid, anhydrides of these acids, and alkyl (C1-3) esters is preferable. More preferably, it is at least one of acid compounds. In the present invention, the above-described acids, anhydrides of these acids, and alkyl esters of the acids are collectively referred to herein as carboxylic acid compounds.

  The content of the unsaturated aliphatic dicarboxylic acid compound is preferably 20 mol% or more, more preferably 40 mol% or more, and even more preferably 50 mol% or more in the carboxylic acid component from the viewpoint of the pulverization property of the crystalline polyester. 70 mol% or more is more preferable, 80 mol% or more is more preferable, and 98 mol% or more is more preferable.

  Examples of dicarboxylic acid compounds other than unsaturated aliphatic dicarboxylic acid compounds include oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, phthalic acid, isophthalic acid, Examples include terephthalic acid, cyclohexanedicarboxylic acid, anhydrides of these acids, and alkyl (C1-3) esters.

  Examples of the trivalent or higher polyvalent carboxylic acid compounds include trimellitic acid, pyromellitic acid, anhydrides of these acids, and alkyl (carbon number 1 to 3) esters.

  From the viewpoint of pulverization of the crystalline polyester, the carboxylic acid component does not contain a trivalent or higher polyvalent carboxylic acid compound, or even if it is contained, the content is preferably 5 mol% or less, preferably 3 mol%. The following is more preferable, and 1 mol% or less is more preferable.

  In Step 1, the polycondensation reaction between the alcohol component and the carboxylic acid component can be performed in an inert gas atmosphere in the presence of an esterification catalyst such as a tin compound or a titanium compound, and the temperature thereof is 120 to 120. 230 ° C is preferred.

A well-known thing can be used for an esterification catalyst. As the tin compound, fatty acid tin (II) represented by (R ¹ COO) ₂ Sn (where R ¹ represents an alkyl group or alkenyl group having 5 to 19 carbon atoms), (R ² O) ₂ Sn ( R ² represents an alkyl group or an alkenyl group having 6 to 20 carbon atoms), and tin (II) oxide represented by SnO is preferable, and (R ¹ COO) ₂ Sn Fatty acid tin (II) and tin oxide (II) represented are more preferable, tin (II) octoate, tin (II) 2-ethylhexanoate, tin (II) stearate and tin (II) oxide are more preferable . Titanium compounds include tetra-n-butyl titanate [Ti (C ₄ H ₉ O) ₄ ], tetrapropyl titanate [Ti (C ₃ H ₇ O) ₄ ], tetrastearyl titanate [Ti (C ₁₈ H ₃₇ O) ₄ ], tetramyristyl titanate [Ti (C ₁₄ H ₂₉ O) ₄ ], tetraoctyl titanate [Ti (C ₈ H ₁₇ O) ₄ ], dioctyl dihydroxy octyl titanate [Ti (C ₈ H ₁₇ O) ₂ (OHC ₈ H ₁₆ O) ₂ ], dimyristyl dioctyl titanate [Ti (C ₁₄ H ₂₉ O) ₂ (C ₈ H ₁₇ O) ₂ ] and the like.

  The above tin compounds and titanium compounds can be used alone or in combination of two or more.

  The amount of the esterification catalyst is preferably 0.01 to 2.0 parts by weight, more preferably 0.1 to 1.5 parts by weight, and still more preferably 0.2 to 1.0 parts by weight with respect to 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component.

  In the crystalline polyester, the molar ratio of the carboxylic acid component to the alcohol component (carboxylic acid component / alcohol component) is preferably 0.9 or more and less than 1.0, and more preferably 0.95 or more and less than 1.0.

  In the polycondensation reaction, all monomers are charged together to increase the strength of the resin, or divalent monomers are first reacted to reduce low molecular weight components, and then trivalent or higher You may use the method of adding a body and making it react. Further, the reaction may be accelerated by reducing the pressure of the reaction system in the latter half of the polymerization.

  In step 2, as one or more selected from a compound having a catechol skeleton and a compound having a hydroquinone skeleton (hereinafter also simply referred to as catechols), a compound having a catechol skeleton such as t-butylcatechol and 3-phenylcatechol; Examples thereof include compounds having a hydroquinone skeleton such as hydroquinone, 4-methoxyphenol (hydroquinone monomethyl ether) and 2,5-di-t-butyl hydroquinone. Among these, reaction control, that is, crystalline polyester From the viewpoint of making the grindability constant, t-butylcatechol is preferable.

  The amount of catechol used is preferably 0.01 to 3 parts by weight, more preferably 0.02 to 1 part by weight, and 0.03 to 0.5 parts by weight, based on 100 parts by weight of the total amount of the alcohol component and carboxylic acid component used in the condensation polymerization reaction. Is more preferable.

  Examples of radical polymerization initiators include azo compounds such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile), dibutyl peroxide, dicumyl peroxide, and tartaric acid. Well-known radical polymerization initiators, such as organic peroxides, such as a butyl peroxy 2-ethylhexyl monocarbonate, are mentioned.

  The amount of the radical polymerization initiator used is preferably 0.01 to 3 parts by weight, more preferably 0.02 to 1 part by weight, more preferably 0.03 to 0.5 parts by weight based on 100 parts by weight of the total amount of the alcohol component and carboxylic acid component used in the condensation polymerization reaction. More preferred are parts by weight, preferably 0.02 to 1 part by weight, more preferably 0.04 to 0.5 part by weight, and still more preferably 0.05 to 0.3 part by weight based on 100 parts by weight of the unsaturated aliphatic dicarboxylic acid compound. The weight ratio of catechols to radical polymerization initiator (catechols / radical polymerization initiator) is preferably 1/110 to 10/1, more preferably 1/5 to 5/1, and 1/2 to 3/1. Is more preferable.

  The radical polymerization initiator is preferably mixed with an alcohol having 2 to 18 carbon atoms and added to the reaction system. By mixing the radical polymerization initiator with the alcohol having 2 to 18 carbon atoms, that is, diluting with the alcohol having 2 to 18 carbon atoms and adding it to the reaction system, the crystallinity with respect to the added amount of the radical polymerization initiator The fluctuation of the pulverization property of the polyester is further reduced, and a more stable polyester can be produced. In addition, by using the radical polymerization initiator diluted with alcohol, the same physical properties can be obtained regardless of the total amount used, that is, even if the amount used is small, and stable physical properties are easily obtained. This is because, when a radical initiator is added alone, it is partially deactivated before dripping due to the influence of humidity and reaction water, whereas it is prevented from being deactivated by adding it in alcohol. It is estimated that it is possible.

  Carbon number of the alcohol mixed with the radical polymerization initiator is 2-18, preferably 2-6. The alcohol mixed with the radical polymerization initiator is preferably a saturated aliphatic alcohol, more preferably a primary alcohol, from the viewpoint of pulverizability of the crystalline polyester.

  In step 2, the catechols and the radical polymerization initiator are preferably added when the reaction rate of the condensation polymerization reaction is preferably 40 to 90%, more preferably 60 to 85%, from the viewpoint of reaction control. Here, the reaction rate of the polycondensation reaction is a value converted to 100% when the theoretical reaction water is completely discharged. For example, the reaction rate of 80% is the time when 80% of the theoretical reaction water is discharged. .

  Further, the radical polymerization initiator is preferably added at the same time as the catechols or after the addition of the catechols from the viewpoint of controlling the reaction, that is, making the pulverizing property of the crystalline polyester constant, and after adding the catechols. It is more preferable to add. When the radical polymerization initiator is added after adding the catechols, it is preferable that the catechols are uniformly dispersed in the reaction system, depending on the reaction scale. It is preferable to add the radical polymerization initiator after stirring the reaction system for about minutes to 2 hours, more preferably about 15 minutes to 1 hour.

  The addition time of the radical polymerization initiator is from the viewpoint of improving the pulverizability of the crystalline polyester, from the viewpoint of safety to generate heat, the viewpoint of temperature control of the reaction tank, the suppression of pulverization variation between the polyesters of the crystalline polyester, Although depending on the reaction scale, it is preferable to add gradually at an approximately equal rate, preferably over about 15 minutes to 1 hour, more preferably over 25 to 50 minutes.

  In Step 2, the temperature in the reaction system when adding the radical polymerization initiator is preferably 100 to 200 ° C, more preferably 140 to 180 ° C, from the viewpoint of proceeding the addition polymerization reaction with the radical polymerization initiator.

  Although depending on the reaction scale, the reaction time is usually preferably from 30 minutes to 5 hours, more preferably from 30 minutes to 3 hours.

  After the addition polymerization reaction, further condensation polymerization reaction is preferably performed from the viewpoint of the pulverization property of the crystalline polyester and the softening point of the resin. In that case, the reaction temperature is preferably 190 to 230 ° C, more preferably 190 to 210 ° C.

  The melting point of the crystalline polyester is preferably from 70 to 140 ° C., more preferably from 80 to 120 ° C., still more preferably from 90 to 115 ° C., from the viewpoint of low-temperature fixability of the toner. The melting point of the crystalline polyester can be determined as the maximum peak temperature of the endothermic resin described later.

  The softening point of the crystalline polyester is preferably 60 to 130 ° C., more preferably 70 to 125 ° C., and still more preferably 85 to 120 ° C. from the viewpoint of low-temperature fixability of the toner. The melting point and softening point of the crystalline polyester can be easily adjusted by adjusting the raw material monomer composition, the polymerization initiator, the molecular weight, the catalyst amount, etc., or by selecting the reaction conditions.

  The crystalline polyester obtained by the method of the present invention has small pulverization variations, and the kneaded product can be pulverized with high production efficiency under the same pulverization conditions in the manufacturing process of the pulverized toner. In addition, it has moderate compatibility with amorphous polyester and can maintain appropriate crystallinity even after melt-kneading with amorphous polyester, and recrystallization after melt-kneading with amorphous polyester is possible. Promoted. Therefore, the present invention further includes a method for producing a pulverized toner using the crystalline polyester and the amorphous polyester obtained by the method of the present invention as a binder resin, that is, the method includes the crystalline polyester and the amorphous polyester. A method for producing a toner is provided, which includes a step of melt-kneading a toner raw material to be obtained and pulverizing the obtained melt-kneaded product.

  Amorphous polyester is also obtained by condensation polymerization of an alcohol component and a carboxylic acid component as raw material monomers, as in the case of crystalline polyester, and the alcohol component is an amorphous resin such as an aromatic diol. It is preferable that the monomer which accelerates | stimulates quality contains.

  Examples of aromatic diols that promote the amorphization of the resin include polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane. Formula (I):

(Wherein R ³ O and OR ³ are oxyalkylene groups, R ³ is an ethylene and / or propylene group, x and y indicate the number of moles of alkylene oxide added, each being a positive number, The average value of the sum of y and y is preferably 1 to 16, more preferably 1 to 8, and even more preferably 1.5 to 4)
An alkylene oxide adduct of bisphenol A represented by:

  The content of the alkylene oxide adduct of bisphenol A represented by the formula (I) is preferably 50 mol% or more, more preferably 70 mol% or more, and more preferably 90 mol in the alcohol component from the viewpoint of charge stability of the toner. % Or more is more preferable.

  Examples of the dicarboxylic acid compound contained in the carboxylic acid component include fumaric acid, adipic acid, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, etc., C2-C30, preferably 2-8 aliphatic dicarboxylic acid; phthalic acid, isophthalic acid, terephthalic acid etc. aromatic dicarboxylic acid; cyclohexane dicarboxylic acid etc. fat Cyclic dicarboxylic acids; anhydrides of these acids, and alkyl (C1-3) esters of acids.

  In addition, trivalent or higher polyvalent carboxylic acid compounds include trimellitic or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides of these acids, and alkyl alkyls (1 to 3 carbon atoms). Examples include esters.

  A monovalent alcohol may be appropriately contained in the alcohol component, and a monovalent carboxylic acid compound may be appropriately contained in the carboxylic acid component in order to adjust the molecular weight of the resin.

  The amorphous polyester is obtained by polycondensing an alcohol component and a carboxylic acid component at 180 to 250 ° C., for example, in an inert gas atmosphere, if necessary, in the presence of an esterification catalyst, catechols and the like.

  The softening point of the amorphous polyester is preferably 90 to 160 ° C., more preferably 95 to 155 ° C., and further preferably 115 to 150 ° C. from the viewpoint of low-temperature fixability and storage stability of the toner.

  The glass transition point of the amorphous polyester is preferably 45 to 85 ° C., more preferably 50 to 80 ° C., and further preferably 58 to 75 ° C. from the viewpoint of low-temperature fixability and storage stability of the toner. The glass transition point is a physical property peculiar to an amorphous resin, and is distinguished from the maximum peak temperature of endotherm.

  In addition, the acid value of the amorphous polyester is preferably 1 to 90 mgKOH / g, more preferably 2 to 90 mgKOH / g, and further preferably 3 to 88 mgKOH / g, from the viewpoints of chargeability and environmental stability of the toner.

  In the present invention, the polyester may be a polyester modified to such an extent that the characteristics are not substantially impaired. Examples of the modified polyester include grafting and blocking with phenol, urethane, epoxy and the like by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, and the like. And a composite resin having two or more kinds of resin units including a polyester unit.

  In the binder resin, the weight ratio of crystalline polyester to amorphous polyester (crystalline polyester / amorphous polyester) is preferably 10/90 to 40/60 from the viewpoint of low-temperature fixability and durability of the toner. 10/90 to 30/70 are more preferable, and 20/80 to 30/70 are more preferable.

  In the binder resin, a resin other than a polyester such as a vinyl resin, an epoxy resin, a polycarbonate, or a polyurethane may be appropriately contained as long as the effects of the present invention are not impaired. The total content of the crystalline polyester and the amorphous polyester is preferably 80% by weight or more, more preferably 90% by weight or more, and still more preferably 100% by weight in the binder resin.

  The toner obtained by the method of the present invention may use a crystal nucleating agent. You may contain. The crystal nucleating agent increases the crystal growth rate and reduces the amorphous part, thereby increasing the hardness of the toner.

  As the crystal nucleating agent, an aromatic amide compound is preferable from the viewpoint of the effect of promoting crystallization. Specifically, N, N′-dicyclohexyl-2,6-naphthalenedicarboxamide, N, N′-dicyclooctyl- Examples include 2,6-naphthalenedicarboxamide, N, N′-dicyclododecyl-2,6-naphthalenedicarboxamide, N, N′-dicyclohexyl-4,4′-biphenyldicarboxamide.

  The content of the aromatic amide compound is preferably 0.1 to 5.0 parts by weight, more preferably 0.5 to 3.0 parts by weight, and more preferably 1.0 to 100 parts by weight of the binder resin from the viewpoint of low-temperature fixability and storage stability of the toner. More preferred is ~ 2.0 parts by weight.

  Further, the toner includes a colorant, a release agent, a charge control agent, a magnetic powder, a fluidity improver, a conductivity modifier, an extender pigment, a reinforcing filler such as a fibrous substance, an antioxidant, an anti-aging agent, Additives such as a cleaning property improving agent may be appropriately contained.

  As the colorant, all of dyes and pigments used as toner colorants can be used. Carbon black, black pigment, 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, Isoindoline, Disazo yellow and the like can be used alone or in combination of two or more. The toner may be either black toner or color toner.

  The content of the colorant is preferably 1 to 40 parts by weight and more preferably 2 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  Examples of the charge control agent include chromium-based azo dyes, iron-based azo dyes, aluminum azo dyes, salicylic acid metal complexes, and the like, and these can be used alone or in admixture of two or more.

  The content of the charge control agent is preferably 0.1 to 8 parts by weight and more preferably 0.5 to 7 parts by weight with respect to 100 parts by weight of the binder resin.

  Release agents include polyolefin wax, paraffin wax, silicones; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide; carnauba wax, rice wax, candelilla wax, wood wax, jojoba Plant waxes such as oils; animal waxes such as beeswax; waxes such as mineral and petroleum waxes such as montan wax, ozokerite, ceresin, microcrystalline wax, and Fischer-Tropsch wax, which are used alone or in combination of two or more Can be mixed and 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 to 10 parts by weight, more preferably 1 to 8 parts by weight, and more preferably 1.5 to 7 parts by weight from the viewpoint of dispersibility in the binder resin with respect to 100 parts by weight of the binder resin. Part by weight is more preferred.

  As a method for producing the toner of the present invention, a method including a step of melt-kneading the toner raw material containing the crystalline polyester and the amorphous polyester of the present invention and a step of pulverizing the obtained kneaded product is preferable. Since the crystalline polyester of the present invention has a slightly lower compatibility with an amorphous polyester than a general crystalline polyester, a decrease in crystallinity can be suppressed even when melt-kneaded with the amorphous polyester.

  The mixing weight ratio of crystalline polyester to amorphous polyester (crystalline polyester / amorphous polyester) during melt kneading is 10/90 to 40 / from the viewpoint of low-temperature fixability and durability of the toner. 60 is preferable, 10/90 to 30/70 is more preferable, and 20/80 to 30/70 is still more preferable.

  For melt kneading of raw materials, for example, crystalline polyester, amorphous polyester, colorant and the like are appropriately mixed with a mixer such as a Henschel mixer or a super mixer, and then a sealed kneader or a single or twin screw extruder, It can be carried out using a kneader such as an open roll kneader.

  The temperature at the time of melt-kneading is not particularly limited as long as each raw material can be sufficiently mixed, but is preferably (Ta-30) ° C. or more and (Ta + 40) ° C. or less. Here, Ta is a weight average softening point (° C.) obtained by weighted averaging of the softening points of the respective binder resins. Specifically, 100 to 150 ° C is preferable, and 110 to 140 ° C is more preferable.

  In the present invention, after the melt-kneading step, it is preferable to perform a step of cooling the obtained melt-kneaded product and further heating and holding it before the pulverizing step. By the heating and holding step, crystallization can be promoted and amorphous portions can be reduced.

From the viewpoint of effectively controlling recrystallization and shape while suppressing the occurrence of caking and agglomerates, the heating and holding step has a heating temperature t (° C.) of
Preferably Tg ₁ -20≤t≤Tm,
(In the formula, Tg ₁ is the glass transition point (° C) of amorphous polyester, and Tm is the melting point (° C) of crystalline polyester)
It is desirable to carry out under conditions that satisfy Specifically, 40-100 degreeC is preferable and 50-80 degreeC is more preferable.

  From the viewpoint of promoting crystallization, it is preferable that the melt-kneaded product to be heated and held is once cooled to a temperature lower than the above temperature and then heated to the above temperature range.

  The time of the heating and holding step is preferably 2 to 36 hours, more preferably 5 to 30 hours, and further preferably 5 to 12 hours from the viewpoints of productivity, recrystallization, and shape control.

  An oven or the like can be used for the heating and holding step. For example, when an oven is used, the heating and holding step can be performed by holding the melt-kneaded product at a constant temperature in the oven. Further, a thermo-hygrostat or a vibrating fluidized bed (VIA-16D type (manufactured by Chuo Kako Co., Ltd.)) can be used.

  After the melt-kneading step or the heating and holding step, the kneaded product is pulverized using a pulverizer in the step, and a toner can be produced through a classification step and the like as appropriate. By using the crystalline polyester with controlled pulverizability obtained by the method of the present invention, the production efficiency at the time of pulverization can be increased.

The volume median particle size (D ₅₀ ) of the toner is preferably 3 to 15 μm, more preferably 3 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.

  An external additive may be added to the surface of the toner. Examples of the external additive include inorganic fine particles such as silica, alumina, titanium oxide, zirconia, tin oxide, and zinc oxide, and organic fine particles such as resin fine particles. It may be given. The addition amount of the external additive is preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the toner particles before being processed with the external additive.

  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.

[Softening point of resin]
Using a flow tester (Shimadzu Corporation, CFT-500D), a 1 g sample is heated at a heating rate of 6 ° C / min, and a 1.96 MPa load is applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. . 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.

[Maximum peak temperature of resin endotherm]
Using a differential scanning calorimeter (DSC Q20, manufactured by TA Instruments Japan), the sample was heated to 200 ° C and cooled to 0 ° C at a temperature decrease rate of 10 ° C / min. Increase the temperature at 10 ° C / min to obtain the maximum endothermic peak temperature.

[Glass transition point of resin]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), weigh 0.01 to 0.02 g of the sample into an aluminum pan, raise the temperature to 200 ° C, and from that temperature to 0 ° C at a rate of 10 ° C / min. The temperature of the cooled sample is raised at a heating rate of 10 ° C / min, and the temperature at the intersection of the base line extension below the maximum peak temperature of endotherm and the tangent that indicates the maximum slope from the peak rise to the peak apex To do.

[Acid value of the resin]
Measured according to the method of JIS K0070. However, only the measurement solvent was 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)).

[Melting point of release agent]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), the temperature was raised to 200 ° C, and the sample was cooled to 0 ° C at a temperature drop rate of 10 ° C / min. The maximum peak temperature of heat of fusion is taken as the melting point.

[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 a 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 into 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).

Examples 1-3
After putting the raw material monomers shown in Table 1 into a 10-liter four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer and a thermocouple, and reacting at 160 ° C. until the reaction rate reaches 80%. Then, t-butylcatechol shown in Table 1 was added, stirred for 30 minutes, and then dibutyl peroxide obtained by mixing dibutyl peroxide (radical polymerization initiator) shown in Table 1 with ethanol at the same temperature (160 ° C.). A 20 wt% ethanol solution of oxide was added dropwise over the time shown in Table 1. After dropping, the temperature was raised to 200 ° C. and reacted at 8 kPa for 15 minutes to obtain a crystalline polyester.

Examples 4-6
After putting the raw material monomers shown in Table 1 into a 10-liter four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer and a thermocouple, and reacting at 160 ° C. until the reaction rate reaches 80%. Then, t-butylcatechol shown in Table 1 was added, and after stirring for 30 minutes, dibutyl peroxide (radical polymerization initiator) shown in Table 1 was added dropwise over the time shown in Table 1. After dropping, the temperature was raised to 200 ° C. and reacted at 8 kPa for 15 minutes to obtain a crystalline polyester.

Comparative Examples 1-3
After putting the raw material monomers shown in Table 1 into a 10-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and reacting at 160 ° C. until the reaction rate reaches 80%. Then, dibutyl peroxide (radical polymerization initiator) shown in Table 1 was dropped over the time shown in Table 1. After dropping, the temperature was raised to 200 ° C. and reacted at 8 kPa for 15 minutes to obtain a crystalline polyester.

  The pulverization index of the obtained crystalline polyester was measured by the following method. The smaller the grinding index, the better the grindability. The pulverization index is preferably smaller, and usually 40 or less.

[Resin grinding index]
From the pulverized resin powder, a powder of 0.71 mm or more and 1 mm or less was separated using a 22 mesh and 16 mesh sieve, and 20 g was put into a National Coffee Mill MK-61M and pulverized for 10 seconds. The obtained powder was sieved with an aperture of 0.5 mm (30 mesh), the weight A remaining on the sieve was measured, and a value of A / 20 × 100 was calculated as a grinding index. A lower pulverization index is preferred.

From the above results, since Examples 1 to 6 use catechols, it is understood that there is little variation in the pulverizability of the crystalline polyester depending on the dropping time. In particular, Examples 1 to 3 in which the radical polymerization initiator was diluted with alcohol were added, and compared to Examples 4 to 6, there was less variation in pulverization of the crystalline polyester depending on the dropping time, and pulverization was also high. . Moreover, in Examples 4-6, although the quantity of the radical polymerization initiator was used more than Examples 1-3, the grindability of crystalline polyester is equivalent to Examples 1-3.
On the other hand, Comparative Examples 1 to 3 in which no catechols are used have a large variation in the pulverization property of the crystalline polyester depending on the dropping time of the radical polymerization initiator. In Comparative Example 2, it was difficult to control the temperature of the reaction tank because the reactivity of the radical polymerization initiator was high.

  Further, when Example 1 (SD = 0.84), Example 4 (SD = 1.14), and Comparative Example 1 (SD = 3.05), which have the same dropping time, are compared, the pulverization index of the crystalline polyester of Comparative Example 1 The variation was the largest. Here, the value in parentheses indicates the SD (standard deviation) value of the pulverization index of the crystalline polyester obtained by repeating 5 times under each condition.

Production Example 1 of Amorphous Polyester [Resin a]
Raw materials other than trimellitic anhydride shown in Table 2 and 40 g of tin (II) 2-ethylhexanoate (esterification catalyst), 4 liters of 10 liters equipped with nitrogen introduction tube, dehydration tube, stirrer and thermocouple The flask was placed in a flask, reacted at 230 ° C. for 8 hours, and then reacted at 8.3 kPa for 1 hour. Further, trimellitic anhydride was added at 210 ° C. and reacted until reaching the softening point shown in Table 2 to obtain an amorphous polyester.

Example of Toner Production 20 parts by weight of crystalline polyester of Examples 1 to 6 or Comparative Examples 1 to 3, 80 parts by weight of resin a, ECB-301 colorant (manufactured by Dainichi Seika Co., Ltd., CI Pigment Blue 15: 3) 5.0 parts by weight, 1.0 part by weight of negatively chargeable charge control agent “LR-147” (manufactured by Nippon Carlit Co., Ltd.) After thoroughly stirring with a Henschel mixer, the mixture was melt kneaded using a co-rotating twin screw extruder having a total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm. The rotation speed of the roll was 200 r / min, the heating temperature in the roll was 120 ° C., the feed rate of the mixture was 10 kg / hr, and the average residence time was about 18 seconds. The obtained kneaded product was rolled and cooled with a cooling roll, heated and held at 60 ° C. for 8 hours in an oven, and then volume-median particle size was measured with a jet mill (I-2 type pulverizer, manufactured by Nippon Pneumatic Co., Ltd.). (D ₅₀ ) 5.5 μm toner particles were obtained.

  External additive `` Aerosil R-972 '' (hydrophobic silica, manufactured by Nippon Aerosil Co., Ltd.) 0.5 part by weight and `` NAX-50 '' (hydrophobic silica, manufactured by Nippon Aerosil Co., Ltd.) 1.0 with respect to 100 parts by weight of the obtained toner particles A toner was obtained by adding parts by weight and mixing with a Henschel mixer at 3600 r / min for 5 minutes.

In order to obtain toner particles having the same volume-median particle size (D ₅₀ ) (5.5 μm) using the above-mentioned jet mill I-2 type pulverizer at a feed rate of 2.5 kg / hr, the pressure is set to It needs to be adjusted.
For example, in the above production conditions, when the pulverizability index of the crystalline polyester is 23, it is 0.44 pascal, when the pulverizability index is 28, it is 0.50 pascal, and when the pulverizability index is 34, it is 0.58 pascal. According to the method using the crystalline polyester obtained in Examples 1 to 6 and having a small variation in grindability index, the conditions of the jet mill can be used constant, so that the production efficiency can be increased.

  The crystalline polyester obtained by the method of the present invention is suitably used as a binder resin for a toner suitably used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method and the like. It is done.

Claims (7)

Step 1: Step of polycondensing an alcohol component containing an α, ω-linear aliphatic diol having 2 to 8 carbon atoms and a carboxylic acid component containing an unsaturated aliphatic dicarboxylic acid compound, and Step 2: Step Including a step of obtaining a crystalline polyester by adding one or more selected from a compound having a catechol skeleton and a compound having a hydroquinone skeleton and a radical polymerization initiator during or after the polycondensation reaction of 1 A method for producing polyester.   The manufacturing method of Claim 1 which mixes and adds a radical polymerization initiator with a C2-C18 alcohol in the process 2.   The production method according to claim 1 or 2, wherein the content of the unsaturated aliphatic dicarboxylic acid compound is 20 mol% or more in the carboxylic acid component.   The manufacturing method in any one of Claims 1-3 whose temperature in the reaction system at the time of adding a radical polymerization initiator is 100-200 degreeC.   The manufacturing method in any one of Claims 1-4 which adds a radical polymerization initiator after adding 1 or more types chosen from the compound which has a catechol skeleton, and the compound which has a hydroquinone skeleton.   A crystalline polyester obtained by the method according to claim 1.   A method for producing a toner, comprising melt-kneading a toner raw material containing the crystalline polyester according to claim 6 and an amorphous polyester, and pulverizing the obtained melt-kneaded product.