JP2010152102A - Method for manufacturing toner for developing electrostatic charge image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing toner for developing an electrostatic charge image using crystalline polyester and amorphous resin together, the toner being excellent in thermal durability as well as low temperature fixability; and to provide the toner for developing the electrostatic charge image to be obtained by the method. <P>SOLUTION: The method for manufacturing the toner for developing the electrostatic charge image includes: a step (melting/kneading process) of melting/kneading binder resin containing the crystalline polyester and the amorphous resin as principal components at 100-160°C; a step (heat treatment process) of performing heat treatment to a melted/kneaded object obtained in the melting/kneading process by immersing the object in a liquid medium at 50-80°C; and a step (pulverization process) of cooling a treated object obtained by the heat treatment process and pulverizing the object. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a toner for developing an electrostatic image used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and for developing an electrostatic image obtained by the method. It relates to toner.

  In Patent Document 1, crystalline polyester and amorphous polyester are melt-kneaded, and the melt-kneaded product is subjected to heat treatment at a specific temperature and time, thereby improving low-temperature fixability, grindability and storage stability. In addition, a method for producing a toner is disclosed, but as a heat treatment method, a method of holding a melt-kneaded material in an oven is described.

In Patent Document 2, a kneading step is performed between a kneading step and a kneading step of a binder resin containing a block copolymer or a graft copolymer of a crystalline polyester and an amorphous vinyl polymer. A method for producing a toner including a step of heat-treating the kneaded product is disclosed, and a specific method for the heat-treatment step includes a method using an oven.
JP 2005-308995 A Japanese Patent Application Laid-Open No. 64-35456

  Toner that uses both crystalline polyester and amorphous polyester improves low-temperature fixability, but tends to be poorly fixed at high temperatures due to thermal fusing, and durability is a problem during continuous printing. Become.

  Further, as the electrostatic charge image developing device is increased in speed and developed in a large amount, the toner is subjected to strong mechanical stress at a relatively high temperature, which is more than the techniques disclosed in Patent Documents 1 and 2. It is desired to improve the thermal durability of the toner.

  An object of the present invention is an electrostatic charge image developing toner using a combination of a crystalline polyester and an amorphous resin, in addition to low-temperature fixability, in addition to thermal durability (hereinafter also simply referred to as durability). Another object of the present invention is to provide a method for producing a toner for developing an electrostatic charge image that is excellent, and a toner for developing an electrostatic charge image obtained by the method.

  As a result of repeated studies to solve the above problems, the present inventors have melt-kneaded a toner raw material containing a binder resin containing a crystalline polyester and an amorphous resin, It has been found that by immersing in a liquid medium, a toner for developing an electrostatic image having excellent low-temperature fixability and excellent thermal durability can be obtained, and the present invention has been completed.

That is, the present invention
[1] A step of melt-kneading a binder resin containing a crystalline polyester and an amorphous resin as main components at 100 to 160 ° C. (melt-kneading step), and 50 to 50 of the melt-kneaded product obtained in the melt-kneading step A toner for developing electrostatic images, comprising a step of heat treatment by dipping in a liquid medium at 80 ° C. (heat treatment step), and a step of crushing (pulverization step) the product obtained in the heat treatment step after cooling. Manufacturing method,
And [2] A toner for developing an electrostatic image obtained by the production method of [1].
About.

  By the method of the present invention, a toner having good low-temperature fixability and thermal durability can be obtained.

  The present invention includes a step of melt kneading a binder resin containing crystalline polyester and an amorphous resin as main components at 100 to 160 ° C. (melt kneading step), and heating the melt kneaded product obtained in the melt kneading step. A method for producing a toner for developing an electrostatic charge image, comprising: a step of treating (heat treatment step); and a step of crushing (grinding step) after cooling the processed product obtained in the heat treatment step. The process is greatly characterized in that the melt-kneaded product obtained in the melt-kneading process is a process of immersing in a liquid medium at a specific temperature and heat-treating. In the present specification, “main component” means that the content in the binder resin is 95% by weight or more, and “heat treatment” means below the softening point of the toner and above the glass transition point. It means to process at the temperature of. Further, the “liquid medium” is a medium which is not limited in viscosity and is liquid at the heat treatment temperature, and a specific example will be described later. The softening point and glass transition point of the toner are measured by the methods described in the examples below.

  In the present invention, from the viewpoint of improving thermal durability (hereinafter also simply referred to as durability), a binder resin containing a crystalline polyester and an amorphous resin is subjected to a heat treatment. In general, the heat treatment step has the effect of forming a phase separation structure between crystalline polyester and amorphous resin, stabilizing individual resins, and fully exhibiting the characteristics of each resin. is there. In the present invention, the heat treatment method is a method of immersing in a liquid medium at a specific temperature, so that the heat treatment is generally performed more than when heat treatment is performed by adjusting the temperature of a gas phase atmosphere such as an oven. Since it is excellent in terms of conductivity, heat capacity, and uniformity due to stirring, it is estimated that the binder resin can be uniformly and quickly brought to a predetermined temperature. In addition, since the binder resin after the melt-kneading process and before the pulverization process can be heat-treated in a relatively short time with a relatively large lump surface area, the pulverized toner has a binder resin. It is considered that the phase separation structure exists more uniformly. Although the reason is unknown by such heat treatment, the phase separation structure can be quickly and stably formed, so that a thermal stability is further improved, and a toner having a lower temperature fixability and durability is obtained. It is estimated that It was also expected that the electrical resistance of the binder resin would decrease due to the influence of the solvent by immersing it in a liquid medium such as water, and this would adversely affect the chargeability of the resulting toner, but this would affect the chargeability. There wasn't.

  In the melt-kneading step of the production method of the present invention, a binder resin containing a crystalline polyester and an amorphous resin as main components is melt-kneaded at 100 to 160 ° C.

  The crystallinity of the resin is expressed by the ratio between the softening point and the maximum endothermic peak temperature in the differential scanning calorimeter, that is, [softening point / maximum endothermic peak temperature]. When it 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 [softening point / maximum endothermic peak temperature] of 0.6 to 1.5, preferably 0.8 to 1.2, and “amorphous resin” means “softening point”. / Maximum endothermic peak temperature] refers to a resin having a value greater than 1.5 or less than 0.6, preferably greater than 1.5. 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. with respect to the softening point, the peak temperature is taken as the melting point, and a peak with a difference from the softening point exceeding 20 ° C. is a peak resulting from the glass transition.

  From the viewpoint of low-temperature fixability of the toner, the crystalline polyester in the present invention includes an alcohol component containing an α, ω-linear alkanediol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound and / or an aromatic dicarboxylic acid compound. It is preferable that the polyester is obtained by condensation polymerization.

  Examples of the α, ω-linear alkanediol include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, etc. 4-Butanediol and 1,6-hexanediol are preferred.

  Alcohol components include 1,2-propanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol, bisphenol A, alkylene oxide adducts of bisphenol A, hydrogenated bisphenol A, sorbitol, pentaerythritol, glycerol, trimethylolpropane, etc. Alcohols other than α, ω-linear alkanediols may be included.

  The content of α, ω-linear alkanediol is preferably 90 to 100 mol%, more preferably 95 to 100 mol% in the alcohol component.

  Aliphatic dicarboxylic acid compounds include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid. Examples thereof include aliphatic dicarboxylic acids such as acids, anhydrides of these acids, alkyl (C1-3) esters, and the like. Among these, fumaric acid is preferable. As described above, the aliphatic dicarboxylic acid compound refers to an aliphatic dicarboxylic acid, its anhydride, and its alkyl (C1-3) ester, and among these, an aliphatic dicarboxylic acid is preferable.

  Examples of the aromatic dicarboxylic acid compound include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, and carboxylic acid compounds such as alkyl (carbon number 1 to 3) esters of these acids. Among these, terephthalic acid is preferable from the viewpoint of environmental stability and durability. As described above, the aromatic dicarboxylic acid compound refers to an aromatic dicarboxylic acid, its anhydride, and its alkyl (C1-3) ester. Among these, an aromatic dicarboxylic acid is preferable.

  The total content of the aliphatic dicarboxylic acid compound and the aromatic dicarboxylic acid compound (hereinafter sometimes collectively referred to as a dicarboxylic acid compound) is preferably 90 to 100 mol%, and 95 to 100 mol% in the carboxylic acid component. Is more preferable.

  The molar ratio of the dicarboxylic acid compound to the α, ω-linear alkanediol in the crystalline polyester (dicarboxylic acid compound / α, ω-linear alkanediol) is α, ω- from the viewpoint of production stability. When the amount of linear alkanediol is large, it is preferably 0.90 or more and less than 1.0, more preferably 0.95 or more and less than 1.0, from the viewpoint that the molecular weight of the resin can be easily adjusted by evaporation during a vacuum reaction.

  Crystalline polyester is an α, ω-linear alkanediol and a dicarboxylic acid compound in an inert gas atmosphere, if necessary using an esterification catalyst, a polymerization inhibitor, etc. at a temperature of 120 to 230 ° C. It can be obtained by condensation polymerization. Specifically, in order to increase the strength of the resin, all monomers are charged at once, or in order to reduce the low molecular weight component, a divalent monomer is first reacted and then a trivalent or higher monomer. You may use the method of adding a monomer 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 order to obtain polyester with high crystallinity, it is preferable to increase the molecular weight, and it is more preferable to carry out the reaction until the viscosity of the reaction solution becomes high. In order to obtain a high molecular weight polyester having a high molecular weight, as described above, the molar ratio of the dicarboxylic acid compound and the α, ω-linear alkanediol is adjusted, the reaction temperature is increased, the amount of catalyst is increased, the pressure is reduced. The reaction conditions such as performing a dehydration reaction for a long time may be selected. A high-power motor can be used to produce a high-molecular-weight polyester having a high molecular weight. However, when the production equipment is not particularly selected, the raw material monomer is a non-reactive low-viscosity resin. A method of reacting with a solvent is also an effective means.

  The amount of the esterification catalyst present in the reaction system is preferably 0.03 to 1 part by weight, more preferably 0.04 to 0.8 part by weight, based on 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component.

  The number average molecular weight of the crystalline polyester is preferably 5,000 to 10,000, more preferably 6,000 to 9,000, because if the number average molecular weight is too low, the storage stability of the toner is adversely affected. In the present specification, the number average molecular weight and the weight average molecular weight of the resin are measured by the methods described in Examples described later. Examples of methods for adjusting the number average molecular weight include a method of adjusting the molar ratio of a dicarboxylic acid compound and an α, ω-linear alkanediol, and an ester such as a reaction temperature, an amount of catalyst, and a dehydration reaction under reduced pressure for a long time. The method of adjusting the reaction conditions for the conversion is exemplified. Specifically, the number average molecular weight can be increased by increasing the proportion of the dicarboxylic acid compound, increasing the reaction temperature, increasing the amount of catalyst, extending the dehydration reaction time, or the like. Further, if the above description is reversed, the number average molecular weight tends to be small.

  Further, from the viewpoint of the durability of the toner, it is preferable that the crystalline polyester contains a high molecular weight component to some extent. Therefore, the weight average molecular weight of the crystalline polyester is preferably 40,000 to 150,000, more preferably 50,000 to 120,000. It is. Examples of the method for adjusting the weight average molecular weight include the same methods as those for adjusting the number average molecular weight described above.

  The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the crystalline polyester is preferably 5 to 20, more preferably 6 to 18, more preferably from the viewpoint of toner durability. 8-15.

  The highest endothermic peak temperature in the differential scanning calorimeter of the crystalline polyester is preferably within 20 ° C. relative to the softening point, that is, the melting point. In the present invention, it is preferably 110 to 140 ° C., more preferably 110 to 130 ° C., and still more preferably 110 to 120 ° C. from the viewpoint of toner fixing properties, storage stability and durability. When two or more crystalline polyesters are used as the binder resin, it is preferable that the weighted average melting point based on the content of the crystalline polyester is within the above range. In the present specification, the maximum peak temperature of endotherm is measured by the method described in Examples described later. Examples of the method for adjusting the maximum endothermic peak temperature include a method for adjusting the number average molecular weight. When the number average molecular weight is increased, the endothermic maximum peak temperature tends to increase, and the number average molecular weight is decreased. Tend.

  The softening point of the crystalline polyester is preferably from 70 to 140 ° C, more preferably from 90 to 130 ° C, and even more preferably from 90 to 120 ° C, from the viewpoint of low-temperature fixability of the toner. When using 2 or more crystalline polyester as binder resin, it is preferable that the weighted average softening point based on the content rate of crystalline polyester exists in the said range. In the present specification, the softening point is measured by the method described in Examples described later. Examples of methods for adjusting the softening point include esterification such as a method of adjusting the molar ratio of a dicarboxylic acid compound and an α, ω-linear alkanediol, a reaction temperature, an amount of catalyst, and a dehydration reaction for a long time under reduced pressure. A method of changing the reaction conditions is included. Specifically, the number average molecular weight can be increased by increasing the proportion of the dicarboxylic acid compound, increasing the reaction temperature, increasing the amount of catalyst, extending the dehydration reaction time, or the like. Further, if the above description is reversed, there is a tendency to become smaller. Further, as described above, in order to adjust the ratio between the softening point and the maximum endothermic peak temperature, the molar ratio of the dicarboxylic acid compound and the α, ω-linear alkanediol is adjusted, the reaction temperature is increased, and the amount of the catalyst is increased. It can be achieved by adjusting the reaction conditions such as dehydration reaction for a long time under reduced pressure.

  Examples of the amorphous resin in the present invention include amorphous polyester, amorphous polyester polyamide, and amorphous styrene-acrylic resin. From the viewpoint of compatibility with crystalline polyester, amorphous polyester is used. preferable.

  As the amorphous polyester, those obtained by polycondensation of an alcohol component containing an alkylene oxide adduct of bisphenol A and a carboxylic acid component containing a dicarboxylic acid compound are preferable.

  For the alcohol component, the formula (I):

(In the formula, RO is an oxyalkylene group, R is an ethylene and / or propylene group, x and y represent the number of added moles of alkylene oxide, each being a positive number, and the average of the sum of x and y) (The value is preferably 1-16, more preferably 1-8, and even more preferably 1.5-4)
Is preferably 90-100 mol%, more preferably 95-100 mol%, still more preferably substantially 100 mol%, in the alcohol component. In the present specification, when the binder resin contains two or more amorphous resins, the content in the alcohol component of the alkylene oxide adduct of bisphenol A means a weighted average content, and the above range It is desirable to be within.

  Examples of alkylene oxide adducts of bisphenol A represented by the formula (I) include polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene-2,2-bis (4-hydroxyphenyl) Examples thereof include alkylene (2 to 3 carbon) oxide (average number of added moles 1 to 16) adducts of bisphenol A such as propane.

  As alcohol components other than the alkylene oxide adduct of bisphenol A, ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol, bisphenol A, hydrogenated bisphenol A, sorbitol , Pentaerythritol, glycerol, trimethylolpropane and the like.

  Examples of the dicarboxylic acid compound include the same aliphatic dicarboxylic acid compounds and aromatic dicarboxylic acid compounds as described above. As the carboxylic acid component, an aliphatic dicarboxylic acid compound exemplified as a raw material for the crystalline polyester such as fumaric acid or a dicarboxylic acid compound containing an aromatic dicarboxylic acid compound having an aromatic ring can be used. From the viewpoint of maintaining a high crystallization rate of the melt-kneaded product depending on the structure, the aromatic dicarboxylic acid compound having an aromatic ring is preferably contained in the carboxylic acid component in an amount of 50 mol% or more, more preferably 90 to 100 mol%, More preferably, it is 95-100 mol%, More preferably, it contains substantially 100 mol%. In the present specification, when the binder resin contains two or more kinds of amorphous resins, the content of the aromatic dicarboxylic acid compound in the carboxylic acid component means a weighted average content, and the above range. It is desirable to be within.

  The carboxylic acid component includes 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, trivalent or higher polyvalent carboxylic acid such as pyromellitic acid, and these Carboxylic acid compounds other than dicarboxylic acid compounds such as acid anhydrides and alkyl (carbon number 1 to 3) esters may be contained.

  In addition, 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 from the viewpoint of adjusting the molecular weight and improving the offset resistance.

  The condensation polymerization of the alcohol component and the carboxylic acid component in the amorphous resin can be performed, for example, in an inert gas atmosphere at a temperature of 180 to 250 ° C., but the effect of the present invention is more remarkably exhibited. From the viewpoint of production, it is preferably carried out in the presence of an esterification catalyst such as tin octylate.

  The abundance of the esterification catalyst in the reaction system is preferably 0.05 to 1 part by weight and more preferably 0.10 to 0.8 part by weight based on 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component.

  The softening point of the amorphous resin is preferably 90 to 140 ° C., more preferably 100 to 130 ° C., from the viewpoint of low-temperature fixability of the toner.

  In the present invention, the amorphous resin is preferably composed of two kinds of amorphous polyesters having a softening point of 10 ° C. or higher, more preferably 10 to 60 ° C. from the viewpoint of low-temperature fixability and offset resistance of the toner. It is preferable to become. Of the two types, the lower softening point polyester (low softening point polyester) has a softening point of preferably 80 to 120 ° C., more preferably 90 to 120 ° C., from the viewpoint of low-temperature fixability of the toner. Of the seeds, the softening point of the polyester having the higher softening point (high softening point polyester) is preferably 120 to 150 ° C, more preferably 120 to 140 ° C, from the viewpoint of offset resistance. In addition, when it consists of 3 or more types of resin, it is preferable that 2 types satisfy | fill the above from the one with much content, for example, when the 2nd and 3rd in the order with many are the same content, it is the largest one Preferably, the second one satisfies the above.

  The weight ratio of the high softening point polyester to the low softening point polyester (high softening point polyester / low softening point polyester) is preferably 1/9 to 9/1, and more preferably 2/8 to 8/2. Further, the high softening point polyester / low softening point polyester is preferably 8/2 to 5/5 when further improving the durability of the toner, and 4/6 or more when further improving the low temperature fixing property of the toner. 2/8 is preferred.

  When the amorphous resin is composed of two or more kinds of amorphous polyesters, the average softening point is preferably from 100 to 140 ° C, more preferably from 110 to 130 ° C, from the viewpoint of low-temperature fixability of the toner. . In this specification, an average softening point means a weighted average softening point, and each softening point is measured by the method as described in the below-mentioned Example.

  The glass transition point of the amorphous resin is preferably from 40 to 70 ° C., more preferably from 50 to 70 ° C., from the viewpoint of low-temperature fixability and durability of the toner. The acid value is preferably 5 to 25 mgKOH / g, and more preferably 5 to 20 mgKOH / g. In this specification, a glass transition point and an acid value are measured by the method as described in the below-mentioned Example.

  In the present invention, the amorphous resin 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 present invention, the binder resin contains a crystalline polyester and an amorphous resin as main components, but the content of the crystalline polyester is 1 in the binder resin from the viewpoint of low-temperature fixability and durability of the toner. It is -35 weight%, 5-35 weight% is preferable and 15-30 weight% is more preferable.

  The total content of the amorphous resin is preferably 65 to 99% by weight, more preferably 65 to 95% by weight, and more preferably 70 to 85% by weight in the binder resin from the viewpoint of low-temperature fixability and durability of the toner. preferable.

  The weight ratio of crystalline polyester to amorphous resin (crystalline polyester / amorphous resin) is preferably 5/95 to 35/65, from the viewpoint of low-temperature fixability and durability of the toner, 15/85 to 30 / 70 is more preferable.

  In the binder resin in the present invention, in addition to the crystalline polyester and the amorphous resin, other binder resins may be appropriately contained as long as the effects of the present invention are not impaired. Examples of other binder resins include binder resins other than polyesters such as vinyl resins, epoxy resins, polycarbonates, and polyurethanes. The total content of the crystalline polyester and the amorphous resin is not particularly limited, but is preferably 95% by weight or more and more preferably 99% by weight or more in the binder resin from the viewpoint of low-temperature fixability of the toner.

  Further, as a toner raw material other than the binder resin in the present invention, a colorant, a release agent, a charge control agent, a magnetic powder, a conductivity adjusting agent, an extender pigment, a reinforcing filler such as a fibrous substance, an antioxidant, an aging Additives such as an inhibitor, a fluidity improver, and a cleanability improver may be used as appropriate.

  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, Isoindoline, Disazo Yellow and the like can be used alone or in admixture of two or more. According to the production method of the present invention The obtained toner may be any of black toner, color toner, and full color toner. The content of the colorant is preferably 1 to 40 parts by weight and more preferably 3 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  As release agents, natural waxes such as polypropylene wax, polyethylene wax, synthetic wax such as Fischer Tropu, coal wax such as montan wax, petroleum wax such as paraffin wax, wax such as alcohol wax, carnauba wax and rice wax An ester wax may be mentioned, and these waxes may be used alone or in admixture of two or more. The total content of the release agent is preferably 1 to 20 parts by weight and more preferably 2 to 10 parts by weight with respect to 100 parts by weight of the binder resin from the viewpoint of fixability.

  The charge control agent may be either a positively chargeable charge control agent or a negatively chargeable charge control agent, and these may be used in combination. Examples of the positively chargeable charge control agent include digrosine dyes, triphenylmethane dyes containing tertiary amines as side chains, quaternary ammonium salt compounds, polyamine resins, and imidazole derivatives. Examples of the negatively chargeable charge control agent include metal-containing azo dyes, copper phthalocyanine dyes, metal complexes of alkyl derivatives of salicylic acid, and boron complexes of benzyl acid. The content of the charge control agent is preferably 0.1 to 5.0 parts by weight and more preferably 0.2 to 4.0 parts by weight with respect to 100 parts by weight of the binder resin.

  In the melt-kneading, it is preferable that the toner raw materials such as the binder resin are uniformly mixed and then melt-kneaded, and the mixing of the toner raw materials may be a method in which all the raw materials such as the binder resin are mixed at a time. The method of dividing and mixing may be used.

  Examples of the mixer used for mixing the toner raw material include a Henschel mixer and a super mixer. From the viewpoint of dispersibility, a Henschel mixer is preferable.

  Melt kneading of the toner material can be performed using a known kneader such as a closed kneader, a single or biaxial extruder, a continuous open roll type kneader, etc. Since it is possible to efficiently and highly disperse the additive in the binder resin without using it, continuous open roll kneading with a supply port and a kneaded material discharge port provided along the axial direction of the roll It is preferable to use a machine.

  The toner raw material mixture may be supplied to the kneader from one supply port, or may be divided and supplied to the kneader from a plurality of supply ports. Is preferably supplied to the kneader from one supply port. The melt kneading temperature is 100 to 160 ° C., preferably 100 to 150 ° C., more preferably 100 to 145 ° C., from the viewpoint of toner durability.

  The continuous open roll type kneader means an open type melt kneading part, and can easily dissipate the kneading heat generated during melt kneading. Further, the continuous open roll type kneader is preferably a kneader equipped with at least two rolls, and the continuous open roll type kneader used in the present invention comprises two rolls having different peripheral speeds, That is, the kneading machine includes two rolls, a high rotation side roll having a high peripheral speed and a low rotation side roll having a low peripheral speed. In the present invention, from the viewpoint of dispersibility, it is desirable that the high rotation side roll is a heating roll and the low rotation side roll is a cooling roll.

  The temperature of the roll can be adjusted by, for example, the temperature of the heat medium passed through the inside of the roll, and each roll may be divided into two or more and the heat medium having different temperatures may be passed through each roll.

  The raw material charging side end temperature of the high rotation side roll is preferably 100 to 160 ° C, more preferably 100 to 150 ° C, and further preferably 100 to 145 ° C. The raw material charging side end temperature of the low rotation side roll is preferably 30 to 100 ° C. The kneaded product discharge side end temperature of the high rotation side roll is preferably 30 to 140 ° C, more preferably 40 to 130 ° C, and still more preferably 50 to 125 ° C. The kneaded product discharge side end temperature of the low rotation side roll is preferably 30 to 100 ° C. In the present invention, when a continuous open roll type kneader is used as the melt kneader, the raw material charging side end temperature of the high rotation side roll is a temperature setting that satisfies the above condition of the melt kneading temperature. desirable.

  The difference in set temperature between the raw material charging side end and the kneaded product discharge side end in the high rotation side roll is preferably 20 to 60 ° C. from the viewpoint of preventing the kneaded product from being detached from the roll. More preferably, it is -50 degreeC, and it is further more preferable that it is 30-50 degreeC. In the low rotation side roll, the difference in set temperature between the raw material charging side end and the kneaded product discharge side end is preferably 0 to 50 ° C., from 0 to 40 ° C. from the viewpoint of mold release agent dispersibility. More preferably, it is more preferably 0 to 20 ° C.

  The peripheral speed of the high rotation side roll is preferably 2 to 100 m / min, and more preferably 4 to 50 m / min. The peripheral speed of the low rotation side roll is preferably 2 to 100 m / min, more preferably 4 to 60 m / min, and further preferably 4 to 50 m / min. Further, the ratio of the peripheral speeds of the two rolls (low rotation side roll / high rotation side roll) is preferably 1/10 to 9/10, more preferably 3/10 to 8/10.

  The structure, size, material, and the like of the roll are not particularly limited, and the roll surface may be any of smooth, corrugated, uneven, and the like. It is preferable that the spiral groove is cut.

  In this way, a melt kneaded product of the toner raw material containing the binder resin containing the crystalline polyester and the amorphous resin is obtained.

  The melt-kneaded product obtained above can be used for a pulverized toner to be pulverized into a toner, or a polymerized toner obtained by dispersing particles in a solvent, but the present invention is a heat treatment step after the melt-kneading step. Since it does not include a step of performing heat treatment other than the above, it is preferably used for producing a pulverized toner.

  In a general toner production method of the pulverized toner, the obtained melt-kneaded product is cooled until reaching a pulverizable hardness and is subjected to a pulverization step. In the present invention, the melt-kneaded product obtained after the melt-kneading step is used. Is subjected to a heat treatment step, followed by a pulverization step.

  In the heat treatment step, the melt-kneaded product obtained in the melt-kneading step is immersed in a liquid medium at 50 to 80 ° C. and heat-treated. The melt-kneaded product subjected to the heat treatment step preferably has a maximum thickness of 2 cm or less from the viewpoint of conducting heat to the center of the melt-kneaded product. If the maximum thickness of the melt-kneaded product discharged from the kneader used in the melt-kneading process is 2 cm or less, it can be used for the heat treatment process as it is, and if it exceeds 2 cm, it is crushed and used for the heat treatment process be able to. The thickness of the melt-kneaded product refers to the thickness of the thinnest portion when one piece of the melt-kneaded product is measured with calipers applied, and the thickness of the thickest portion is referred to as the maximum thickness.

  In the present invention, in the heat treatment step, the melt-kneaded product obtained in the melt-kneading step is 50 to 80 ° C. from the viewpoint of improving the durability of the toner by maintaining the dispersion of the toner additive and rearranging the binder resin molecules. Preferably, it is desirable to immerse in a liquid medium at 50 to 70 ° C., preferably for 3 to 24 hours, more preferably for 3 to 12 hours, and even more preferably for 3 to 7 hours. In addition, this time is the total time immersed in the liquid medium which becomes the said temperature range. Further, from the viewpoint of maintaining dispersion of the toner additive and rearrangement of the binder resin molecules, it is preferable that the upper limit of the temperature range is not exceeded from the start to the end of the heat treatment step.

  In the present invention, the heat treatment step is performed at the above temperature for the above time to promote rearrangement of the resin in the melt-kneaded product, and the durability of the toner is improved by recovering the glass transition temperature once lowered. Presumed. In addition, the portion having a low glass transition temperature easily absorbs impact during pulverization and causes a decrease in pulverization efficiency, but in the present invention, a decrease in the glass transition temperature is suppressed in the heat treatment step before the pulverization step. Therefore, grindability can also be improved.

  For the heat treatment, a water tank filled with a liquid medium adjusted to the temperature can be used. For example, when using a water tank, it can heat-process by immersing a melt-kneaded material in a water tank, and hold | maintaining at fixed temperature. As a water tank, the stainless steel water tank provided with the heater in the jacket part can be used, for example. The water tank preferably has a lid from the viewpoint of keeping the liquid medium warm. Further, the water tank preferably has a stirrer having a stirring blade such as a propeller for stirring the liquid medium in the water tank and a device for circulating the liquid medium.

  The liquid medium is not limited in viscosity, and a medium that is liquid at the heat treatment temperature can be used. Examples thereof include liquids having a boiling point of 100 ° C. or higher, such as water, ethylene glycol, and silicon oil. Water is preferable from the viewpoint of corrosion, penetration, adhesion and other effects, safety and handling properties. The temperature of the liquid medium can be stably maintained by circulating it with a heater having a temperature sensor, a stirring blade, or a temperature control device.

Although the aspect which performs the process of heat-processing is not specifically limited, For example,
Aspect 1: In the process of cooling the obtained melt-kneaded product after the melt-kneading step, the melt-kneaded product is kept under the above heat treatment conditions, then cooled until reaching a grindable hardness, and the next step of the grinding step, etc. Aspect 2 to be used in the process: After the melt-kneading process, the obtained melt-kneaded product is once cooled (preferably 45 ° C. or less) until pulverizable hardness, and then the cooled melt-kneaded product is subjected to the heat treatment process. Then, there is an embodiment in which the melt-kneaded product is cooled again and used for the next step such as a pulverization step. In the present invention, the heat treatment step may be performed in any mode, but from the viewpoint of suppressing aggregation of the additive in the toner, mode 2 is preferable.

  As the content of the crystalline polyester in the binder resin increases, the crystallization rate of the melt-kneaded product tends to increase. However, there are portions in the crystalline polyester that do not have a crystal structure, that is, portions that are not crystallized by heat treatment, and if such portions are present in the melt-kneaded material, the durability tends to be poor. Therefore, durability is improved by promoting crystallization in the entire melt-kneaded product and increasing the crystallization rate by the heat treatment step.

  Thus, a heat-treated product of the melt-kneaded product can be obtained. After the heat treatment, the heat-treated product is allowed to stand on a wire mesh and the liquid medium can be removed from the heat-treated product by natural drying or the like. In the pulverized toner, the heat-treated product is cooled to a pulverizable hardness and then subjected to a pulverization step and a classification step. Specifically, the cooling temperature to reach the pulverizable hardness is preferably 45 ° C. or less, more preferably 0 to 45 ° C., and still more preferably 0 to 35 ° C. The temperature to be defined from the essence of the present invention is the temperature in the melt-kneaded product, but this temperature is defined by the surface temperature of the melt-kneaded product from the viewpoint of temperature measurement. Examples of the cooling method include a method in which the melt-kneaded product is allowed to cool at room temperature (35 ° C. or lower), a method in which the melt-kneaded product is rolled on a cooling roll and cooled.

  The pulverization process may be performed in multiple stages. For example, the heat-treated product after the heat treatment step may be coarsely pulverized to about 1 to 5 mm and further pulverized to a desired particle size.

  The pulverizer used in the pulverization step is not particularly limited. For example, as a pulverizer suitably used for coarse pulverization, an atomizer, a rotoplex, etc., as a pulverizer suitably used for fine pulverization, a jet mill, a collision Examples thereof include a plate mill and a rotary machine mill.

  Examples of the classifier used in the classification process include an air classifier, an inertia classifier, and a sieve classifier. In the classification step, the pulverized product that has been removed due to insufficient pulverization may be subjected to the pulverization step again.

  Although the toner is obtained by the above steps, inorganic fine particles such as hydrophobic silica and resin fine particles may be externally added to the obtained toner surface.

The volume median particle size (D ₅₀ ) of the toner obtained according to the present invention is preferably 4.5 to 6.5 μm, and more preferably 5.5 to 6.0 μm from the viewpoint of image quality and chargeability. 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.

  The toner obtained by the present invention can be used for both a one-component developing toner and a two-component developing toner used by mixing with a carrier, but as a one-component developing toner that requires more heat resistance. More preferably used.

[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. While applying a load of 1.96 MPa with 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.

[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)).

[Maximum peak temperature and melting point of resin endotherm]
Using a differential scanning calorimeter (manufactured by TA Instruments Japan Co., Ltd., Q-100), the sample cooled from room temperature to 0 ° C at a temperature lowering rate of 10 ° C / min is left still for 1 minute, and then the temperature is raised Measure at a rate of 50 ° C / min. Among the observed endothermic peaks, the temperature of the peak on the highest temperature side is defined as the highest endothermic peak temperature. If the maximum peak temperature is within 20 ° C. from the softening point, the melting point is set, and the peak having a difference from the softening point exceeding 20 ° C. is a peak due to glass transition.

[Average molecular weight of resin]
The number average molecular weight and the weight average molecular weight are determined from a chart showing the molecular weight distribution by gel permeation chromatography obtained by the following method.
(1) Preparation of sample solution Dissolve the resin in chloroform so that the concentration is 0.5 g / 100 mL. Next, this solution is filtered using a fluororesin filter having a pore size of 2 μm (FP-200, manufactured by Sumitomo Electric Industries, Ltd.) to remove insoluble components to obtain a sample solution.
(2) Measurement of molecular weight distribution Using the following measuring device and analytical column, flow chloroform at a flow rate of 1 mL per minute as a solution, and stabilize the column in a constant temperature bath at 40 ° C. Inject 100 μL of the sample solution into the sample and perform measurement. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. For the calibration curve at this time, a sample prepared using several types of monodisperse polystyrene as a standard sample is used.
Measuring device: CO-8010 (manufactured by Tosoh Corporation)
Analytical column: GMHXL + G3000HXL (manufactured by Tosoh Corporation)

[Toner glass transition point]
Using a differential scanning calorimeter (manufactured by TA Instruments Japan Co., Ltd., Q-100), the sample cooled from room temperature to 0 ° C at a temperature lowering rate of 10 ° C / min is left still for 1 minute, and then the temperature is raised Measure at a rate of 50 ° C / min. When the difference between the maximum endothermic peak temperature and the softening point is within 20 ° C, an extension of the baseline below the maximum endothermic peak temperature, and a tangent line indicating the maximum slope from the peak of the peak to the peak apex The temperature at the intersection is read as the glass transition point. When the difference between the peak temperature of the endotherm and the softening point exceeds 20 ° C, the peak from the peak of the peak below the peak temperature observed at a temperature lower than the peak temperature of the endotherm The temperature at the point of intersection with the tangent indicating the maximum inclination to the top of is read as the glass transition point.

[Volume-median particle size of toner (D ₅₀ )]
Measuring instrument: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 50μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
Electrolyte: Isoton II (Beckman Coulter)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) is dissolved in the electrolyte so as to have a concentration of 5% by weight to obtain a dispersion.
Dispersion conditions: 10 mg of a measurement sample is added to 5 mL of the above dispersion, and dispersed for 1 minute with an ultrasonic disperser, then 25 mL of electrolyte is added, and further dispersed for 1 minute with an ultrasonic disperser. Prepare a dispersion.
Measurement conditions: By adding the sample dispersion to 100 mL of the electrolytic solution, the particle size of 30,000 particles is adjusted to a concentration that can be measured in 20 seconds, and then 30,000 particles are measured, Determine the volume median particle size (D ₅₀ ).

Production Example 1 of Crystalline Polyester
The raw material monomer shown in Table 1 and tertiary butyl catechol (TBC) 4.2 g (0.04 parts by weight with respect to 100 parts by weight of the total amount of α, ω-linear alkanediol and aliphatic dicarboxylic acid compound) were added to a nitrogen inlet tube, dehydrated The mixture was placed in a 20-liter four-necked flask equipped with a tube, a stirrer, and a thermocouple, reacted at 160 ° C. for 5 hours, then heated to 200 ° C. and reacted for 1 hour. Furthermore, the resin a was obtained by reacting at 8.3 kPa until a resin having a desired molecular weight was obtained.

Production Example 1 of Amorphous Polyester
Raw material monomer and 18.6 g of tin octylate shown in Table 1 (0.2 parts by weight with respect to 100 parts by weight of the total amount of alcohol component and carboxylic acid component) of 20 liters equipped with a nitrogen introduction tube, dehydration tube, stirrer and thermocouple The reaction was carried out at 220 ° C. for 8 hours and then at 8.3 kPa for 1 hour. Furthermore, it was made to react at 210 degreeC until it reached a desired softening point, and resin A was obtained.

Production Example 2 of Amorphous Polyester
Raw material monomers other than trimellitic anhydride shown in Table 1 and 19.3 g of tin octylate (0.2 parts by weight with respect to 100 parts by weight of the total amount of alcohol component and carboxylic acid component) were introduced into a nitrogen introduction tube, dehydration tube, stirrer and thermocouple. Was placed in a 20 liter four-necked flask equipped with a reactor, reacted at 220 ° C. for 8 hours, and then reacted at 8.3 kPa for 1 hour. Further, trimellitic anhydride shown in Table 1 was added at 210 ° C. and reacted until the desired softening point was reached to obtain Resin B.

Examples 1-7 and Comparative Examples 1-5
The types and amounts of binder resins shown in Table 2, carnauba wax “Carnauba Wax C1” (made by Kato Yoko) 2.5 parts by weight, paraffin wax “HNP-9” (made by Nippon Seiwa Co., Ltd.) 2.5 parts by weight, charge control Agent `` LR-147 '' (Nihon Carlit Co., Ltd., boron benzylate complex) 0.5 parts by weight and yellow pigment `` Ero No.-56 '' (Daiichi Seika Co., Ltd., PY74) 3.0 parts by weight in advance using a Henschel mixer After mixing, the mixture was melt kneaded under the following conditions.

[Example of kneading conditions: open roll]
An open roll kneader “NIDEX” (manufactured by Mitsui Mining Co., Ltd., roll outer diameter: 140 cm, effective roll length: 80 cm) was used. The operating conditions of the continuous two-roll kneader are: high rotation side roll (front roll) peripheral speed 28m / min, low rotation side roll (back roll) peripheral speed 19m / min [peripheral speed ratio (low rotation side / High rotation side = 6.8 / 10)], and the roll clearance at the end of the kneaded product supply port was 0.1 mm. The heating medium temperature and cooling medium temperature in the roll are 145 ° C. on the raw material input side of the high rotation side roll and 100 ° C. on the kneaded material discharge side, 35 ° C. on the raw material input side of the low rotation side roll and 35 ° C. on the kneaded material discharge side. there were. The feed rate of the raw material mixture was 4 kg / hour, and the average residence time was about 10 minutes.

  The melt-kneaded material obtained above is cut out from an open roll (one piece size: heat treatment methods A and C are about 5 mm × 5 mm × 50 mm, heat treatment method B is a continuous body of about 5 mm × 5 mm), and the following heating Heat treatment was performed at the temperature and time shown in Table 2 according to any one of treatment methods A to C.

[Heat treatment method A]
500 g of the melted and kneaded material that has been cut out is once cooled to room temperature (25 ° C), and the temperature of the hot water is 2 ° C in a separable flask with a stirring blade (3 L capacity round shape) filled with warm water adjusted to a predetermined temperature. Slowly add so as not to decrease further, and heat treatment for a predetermined time while stirring at about 60 rotations per minute using a blade having a diameter of 7.5 cm. The heat treatment time is the time from when the first piece of the melt-kneaded material is placed in warm water until the start of removal.

[Heat treatment method B]
Place a separable flask with a stirring blade (3L capacity round shape) filled with warm water adjusted to a predetermined temperature at the discharge part of the kneader, and cool 500g of the melted and kneaded material cut out there. (The temperature of the melt-kneaded product is about 90 ° C.) Directly charged, heat treatment is performed for a predetermined time while stirring at about 60 revolutions per minute using a blade having a diameter of 7.5 cm.

[Heat treatment method C]
500 g of the melt-kneaded material cut out is cooled to room temperature (25 ° C.) once, and is placed in a thermostatic chamber (PL-4KT: manufactured by ESPEC Environmental Test Technology Center Co., Ltd.) adjusted to a predetermined temperature. 52 cm × 14 cm) and left as it is, and heat treatment is performed for a predetermined time. The heat treatment time is the time from when the tray containing the melt-kneaded material is placed in the thermostat until it is removed.

The heat-treated product after the heat treatment is cooled, roughly pulverized to about 2 mm or less with a funnel plex, and then pulverized and classified with a jet mill pulverizer and an airflow classifier (IDS: manufactured by Nippon Pneumatic Co., Ltd.). Toners of Examples 1 to 7 and Comparative Examples 1 to 5 having a particle size (D ₅₀ ) of 5.5 μm were obtained.

  The properties of the obtained toner were evaluated according to the following Test Examples 1 and 2. The results are shown in Table 2.

Test Example 1 [low temperature fixability]
Toner is mounted on the non-magnetic one-component developing device `` MicroLine 5400 '' (Oki Data Co., Ltd.), and a solid image of 3 cm x 8 cm is printed on Xerox L paper (A4) with the adhesion amount adjusted to 0.50 mg / cm ² It was taken out unfixed.

  The unfixed image was fixed at a fixing speed of 100 mm / sec every 5 ° C. from 130 ° C. to 200 ° C. with an external fixing device improved by a fixing device of “MicroLine 3050” (manufactured by Oki Data). Then, apply a mending tape (Sumitomo 3M, Scotch 810, 18 mm x 50 m) to the solid image area, and gently peel off the mending tape. The image density before and after peeling the mending tape was measured, and the fixing rate (after tape peeling / before tape application × 100) was calculated. The temperature at which the fixing rate was 70% or more was evaluated as the lowest fixing temperature, and the low temperature fixing property was evaluated. In the toner of this embodiment, the minimum fixing temperature is preferably 160 ° C. or lower.

Test Example 2 [Thermal durability]
The toner of each example and each comparative example was applied to a printer in which the non-magnetic one-component developing device `` MicroLine 5400 '' (Oki Data) was remodeled and the printing speed was set to 23 ppm (equivalent to 23 sheets per minute for A4 vertical feed). The endurance test was conducted at a printing rate of 0.3% in a 40 ° C / 50% RH environment. The thermal durability was evaluated by printing a solid image every 1000 sheets and observing whether white streaks due to blade filming occurred. The test was stopped when generation of white streaks was confirmed, and the test was performed up to 5000 sheets, and the thermal durability was evaluated according to the following evaluation criteria.

[Evaluation criteria for thermal durability]
A: No white streaking up to 5000 sheets B: No white streaking up to 4000 sheets, white streaking with 5000 sheets C: No white streaking up to 2000 sheets, white streaking with 3000 or 4000 sheets D: 2000 sheets or less White streaks

  It can be seen that the toners of the examples are superior in low-temperature fixability and thermal durability compared to the toners of the comparative examples. In particular, the toners of Examples 1 and 2 have the same low-temperature fixability as compared with the toners of Comparative Examples 1 and 2 having the same heat treatment temperature and time, except that the heat treatment method is different. However, it can be seen that the thermal durability is improved.

  The electrostatic image developing toner obtained by the present invention is suitably used for developing a latent image formed by electrophotography, electrostatic recording method, electrostatic printing method and the like.

Claims (4)

  A step of melt kneading a binder resin containing crystalline polyester and an amorphous resin as main components at 100 to 160 ° C. (melt kneading step), and a melt kneaded product obtained in the melt kneading step at 50 to 80 ° C. A method for producing a toner for developing an electrostatic charge image, comprising: a step of immersing in a liquid medium for heat treatment (heat treatment step); and a step of pulverizing the pulverized product after the heat treatment step (pulverization step) .   The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the heat treatment step is a step of heat-treating the melt-kneaded product obtained in the melt-kneading step after cooling to 45 ° C or lower.   The method for producing a toner for developing an electrostatic charge image according to claim 1 or 2, wherein the immersion time in the heat treatment step is 3 to 24 hours.   An electrostatic charge image developing toner obtained by the production method according to claim 1.