JP2003140390A - Resin for toner and toner for non-contact fixing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin for toner showing sharp melting characteristics at a low temperature and no colored state and having excellent blocking resistance, and to provide a toner for a non-contact fixing method using the above resin, the toner which is excellent in the low temperature fixing property, which can realize a simplified fixing device and reduction of the power consumption and which can be preferably used as a color toner capable of developing a favorable color for a monochromatic or full-color high-speed printing machine or the like. SOLUTION: The resin for the toner contains a crystalline polyester resin prepared by polymerizing cyclic aliphatic dialcohol and dicarboxylic acid.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a toner resin which exhibits sharp melting characteristics at low temperatures, is not colored, and has excellent blocking resistance, and is excellent in low-temperature fixing property in a non-contact fixing system using the same. Regarding toner.

[0002]

2. Description of the Related Art A dry developing system is often used as a system for developing an electrostatic charge image in electrophotography or the like. As a method for fixing the toner on the paper surface in the dry developing method, there are a flash fixing method of irradiating light rays and heat rays, a non-contact fixing method such as a radian (oven) heating method, and a contact fixing method using a heat fixing roller or the like. .

The above-mentioned toner is required to have a performance suitable for each fixing method. For example, in the contact fixing method, a part of the toner adheres to the surface of the heat fixing roller and is retransferred to the paper. There is a need for toner that can prevent this. As the toner used in the non-contact fixing method, for example, in JP-A-2001-100456, two kinds of polyester resins having different softening points are used as binders in order to prevent voids and whitening on the printed surface. Toners are disclosed.

In the toner used in the conventional non-contact fixing method, a temperature of more than 180 ° C. was required for fixing on the paper surface, but in order to improve economical efficiency such as power consumption and speed up copying, There has been a demand for a toner that can be fixed at a low temperature. However, a toner that can be fixed at a low temperature has a problem that a blocking phenomenon in which the toner agglomerates due to heat is likely to occur, and the viscosity becomes too high when fixing at a low temperature, resulting in insufficient fluidity of the toner. There is a problem that the printed surface does not have sufficient gloss.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, the present invention provides a toner resin that exhibits sharp melting characteristics at low temperature, is not colored, and has excellent blocking resistance, and non-contact fixing using the same. An object of the present invention is to provide a toner having excellent low-temperature fixability in the system.

[0006]

The present invention is a toner resin containing a crystalline polyester resin obtained by polymerizing a cycloaliphatic dialcohol and a dicarboxylic acid.

In the present specification, the crystalline polyester resin means a polyester resin having a crystallinity of more than 10% when the differential heat is measured by a differential scanning calorimeter, and is referred to as an amorphous polyester resin. Means a polyester resin having a crystallinity of 10% or less. The present invention is described in detail below.

The toner resin of the present invention contains a crystalline polyester resin. The crystalline polyester resin is a polymer obtained by polycondensation of a cycloaliphatic dialcohol and a dicarboxylic acid.

The cycloaliphatic dialcohol has a cis form and a trans form, and the crystalline polyester resin obtained by polymerizing a cycloaliphatic dialcohol and a dicarboxylic acid is the above cycloaliphatic dialcohol. The melting point changes depending on the ratio of the cis form and the trans form. That is, the melting point of the crystalline polyester resin obtained by polymerizing a cycloaliphatic dialcohol and a dicarboxylic acid is increased by increasing the ratio of the trans form in the cycloaliphatic dialcohol,
It goes down by increasing the proportion of cis. Therefore, the above-mentioned cycloaliphatic dialcohol is used as a monomer of the crystalline polyester resin which is the main component of the toner resin of the present invention, and thus the toner resin has been conventionally changed by largely changing the kind and composition of the monomer. The melting point of was adjusted only by changing the ratio of the cis and trans forms of the cycloaliphatic dialcohol. The toner resin of the present invention can adjust the melting point without significantly changing the composition of the monomer of the crystalline polyester resin as the main component and hardly changing the crystallinity, and exhibits a sharp melting characteristic, and the melting point The temperature may be slightly lower than the fixing temperature of the toner. As the melting point,
The temperature is preferably 10 ° C. to several ° C. lower than the fixing temperature, specifically 70 ° C. in consideration of blocking resistance.
The above is preferable. In order to obtain a toner having sharp melting characteristics at low temperature, the melting point of the toner is preferably 70 to 130 ° C, more preferably 90 to 110 ° C.

The cyclic aliphatic dialcohol is not particularly limited and may be an alkylene oxide adduct of a dialcohol, for example, 1,4-cyclohexanedimethanol and 2,2-bis (4-hydroxycyclohexyl) propane. Alkylene oxide adducts such as 2,2-bis (4-hydroxycyclohexyl) propane,
Examples thereof include alicyclic diols such as 1,4-cyclohexanediol.

As the monomer of the crystalline polyester resin, a dialcohol which is not a cycloaliphatic can be blended in addition to the cycloaliphatic dialcohol. The dialcohol that is not a cycloaliphatic is not particularly limited, and examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, and diamine. Propylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol,
Aliphatic diols such as 2,5-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, and bisphenol Aromatic diols and the like. Since bisphenol may color the crystalline polyester resin, it is preferable not to use bisphenol when slight coloring is not preferable.

However, as the dialcohol used as the monomer of the above crystalline polyester resin, a divalent bent dialcohol and a divalent dialcohol having a branched chain are not preferable because they lower the crystallinity of the crystalline polyester resin. . Therefore, it is better not to add a large amount. The divalent bent dialcohol is not particularly limited as long as it is a dialcohol capable of introducing a bent molecular structure into the molecular chain of the polyester resin. For example, an aromatic diol in which the ortho position or the meta position is substituted with a hydroxyl group. ,
Examples thereof include polycyclic aromatic diols having a hydroxyl group at an asymmetric position. Specific examples include diols such as catechol. The divalent dialcohol having a branched chain is not particularly limited, and may be an alkylene oxide adduct of a dialcohol, for example,
Examples thereof include aliphatic diols having a branched alkyl chain and alicyclic diols having a branched alkyl chain that suppress crystallization of the polyester resin due to steric hindrance of the branched chain. Among them, an alicyclic diol in which a plurality of alicyclic diols are linked by a branched alkylene chain is not preferable. In particular,
For example, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentylene glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2 , 5-hexanediol, 2-methyl-2,4-pentanediol, 3-
Methyl-1,3-pentanediol, 2-ethyl-1,
3-hexanediol, 2-butyl-2-ethyl-1,
Aliphatic diols such as 3-propanediol and 2,4-diethyl-1,5-pentanediol; 2,2-bis (4
And alicyclic diols such as alkylene oxide adducts of -hydroxycyclohexyl) propane and 2,2-bis (4-hydroxycyclohexyl) propane.

The dicarboxylic acid is not particularly limited, and examples thereof include o-phthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octylsuccinic acid, cyclohexanedicarboxylic acid,
Examples thereof include naphthalenedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, and their anhydrides and lower alkyl esters. Of these, aliphatic dicarboxylic acids are preferable, and examples thereof include succinic acid, adipic acid, sebacic acid, azelaic acid, octylsuccinic acid, cyclohexanedicarboxylic acid, their anhydrides, and lower alkyl esters. More preferably, it is a linear aliphatic dicarboxylic acid. The above-mentioned dicarboxylic acid more preferably has 4 to 10 carbon atoms. A dicarboxylic acid having a carbon number in this range is easily available, and a polyester resin having excellent melting properties at low temperatures and excellent blocking resistance can be obtained using only an easily available dicarboxylic acid.

However, as the above-mentioned dicarboxylic acid, a divalent bent dicarboxylic acid and a divalent dicarboxylic acid having a branched chain are not preferable because they lower the crystallinity of the crystalline polyester resin. Therefore, it is better not to add a large amount. The divalent bent dicarboxylic acid is not particularly limited as long as it is a dicarboxylic acid capable of introducing a bent molecular structure into the molecular chain of the oligomer, and for example, an aromatic dicarboxylic acid in which the ortho position or the meta position is substituted with a carboxyl group. ,
Examples thereof include polycyclic aromatic dicarboxylic acids having a carboxyl group at an asymmetric position, anhydrides of dicarboxylic acids, and lower esters. Specific examples thereof include dicarboxylic acids such as phthalic anhydride, o-phthalic acid, isophthalic acid, 1,4-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid, and their anhydrides and lower esters. Also, monohydroxymonocarboxylic acid having a bent structure or a branched chain is not preferable because it lowers the crystallinity of the crystalline polyester resin. Examples of the above monohydroxymonocarboxylic acid include salicylic acid and 3-hydroxy-2-
Examples thereof include naphthalenecarboxylic acid. The divalent dicarboxylic acid having a branched chain suppresses crystallization of the polyester resin due to steric hindrance of the branched chain.

The above crystalline polyester resin preferably does not have a cross-linking structure, but when it is desired to improve the resin strength of the toner resin of the present invention at high temperature, the crystalline polyester resin is provided with a cross-linking structure to have a glass transition temperature. In order to make it higher, alcohol or carboxylic acid having a valence of 3 or more may be contained as a monomer. The trihydric or higher alcohol is not particularly limited, and examples thereof include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and sorbitol. The trivalent or higher carboxylic acid is not particularly limited, and examples thereof include trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid,
2,5,7-naphthalene tricarboxylic acid, 1,2,4-
Examples thereof include naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,2,7,8-octanetetracarboxylic acid, and their anhydrides and lower esters.

The crystalline polyester resin preferably has a weight average molecular weight of 2,500 to 50,000 in order to improve the blocking resistance for suppressing the blocking phenomenon. If it is less than 2,500, blocking resistance may not be sufficient, and if it exceeds 50,000, fixability at low temperature may not be sufficient. More preferably 5,000
It is 0 to 30,000.

The method for producing the crystalline polyester resin is not particularly limited. For example, each of the above monomers may be added in an inert gas atmosphere in the presence of an esterification reaction catalyst for 180 to
It can be produced by reacting at a temperature of 290 ° C.

A crystallization nucleating agent may be added to the toner resin of the present invention in order to promote crystallization of the crystalline polyester resin. By the addition, the crystalline polyester resin becomes hard and the blocking resistance can be improved. The crystallization nucleating agent is not particularly limited, for example, talc,
Examples include clay, kaolin, mica, asbestos, silicates, silica, boron nitride, silicon nitride, metal oxides, organic nucleating agents and the like. The compounding amount of the crystallization nucleating agent is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the crystalline polyester resin. The crystallization nucleating agent may be added during the production process of the crystalline polyester resin,
It may be kneaded with a crystalline polyester resin.

The toner resin of the present invention may contain an amorphous polyester resin having a glass transition temperature of 50 ° C. or higher in order to improve blocking resistance.

The toner for non-contact fixing method comprising the resin for toner of the present invention is also one of the present invention. The toner for non-contact fixing method of the present invention is produced, for example, by mixing the toner resin of the present invention used as a binder with a releasing agent, a colorant, a charge control agent, a magnetic material, a cleaning property improving agent and the like. .

The releasing agent is not particularly limited, and examples thereof include olefin wax and paraffin wax such as polypropylene wax and polyethylene wax; long-chain alkyl acrylate wax such as stearyl acrylate wax; aromatic acrylate such as benzyl acrylate wax. Wax etc. are mentioned. Among them, the long-chain alkyl acrylate wax and the aromatic acrylate wax are preferable because they are excellent in compatibility with the toner resin and a highly transparent toner can be obtained.

The colorant is not particularly limited, and examples thereof include carbon black, aniline black, phthalocyanine blue, quinoline yellow lamp black, rhodamine-B and quinacridone. The amount of the colorant compounded is usually 1 with respect to 100 parts by weight of the resin for toner.
It is preferably from 10 to 10 parts by weight.

There are two types of charge control agents, one for positive charging and the other for negative charging. The charge control agent for positive charging is not particularly limited, and examples thereof include nigrosine dye, ammonium salt, pyridinium salt, and azine. The charge control agent for negative charging is not particularly limited, and examples thereof include a chromium complex and an iron complex. The charge control agent is usually added in an amount of 0.1 with respect to 100 parts by weight of the resin for toner.
It is preferably from 10 to 10 parts by weight.

[0024]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Example 1) <Production of crystalline polyester resin> A 60 L reaction vessel was equipped with a distillation column, a water separator, a nitrogen gas introducing pipe, a thermometer and a stirring means according to a conventional method, and under a nitrogen gas atmosphere. 100 mol of adipic acid as a dicarboxylic acid component, 120 mol of 1,4-cyclohexanedimethanol (cis isomer: trans isomer = 3: 7) as a cycloaliphatic component, and titanium tetrabutoxide (TBB) 0 as an esterification polycondensation catalyst. .0
5 mol was charged, and the esterification reaction was carried out at 220 ° C. while distilling the produced water and methanol from the distillation column.
The esterification reaction was terminated when water and methanol were no longer distilled from the distillation column. After completion of the esterification reaction, 6
While sealing the opening of the 0 L reaction vessel to the distillation column,
Open the line from the vacuum pump to 5mmHg in the reaction system.
The pressure was reduced to 240 ° C. and the polycondensation reaction was carried out at 240 ° C. and a rotation speed of 60 rpm, and the free diol produced by the polycondensation reaction was distilled out of the reaction system to obtain a crystalline polyester resin.

<Production of Toner> A charge control agent (manufactured by Hodogaya Chemical Co., Ltd., was added to 100 parts by weight of the obtained crystalline polyester resin.
1 part by weight of TN-105) and 5 parts by weight of magenta pigment belonging to Carmine 6B were added, thoroughly mixed with a Henschel mixer, melt-kneaded at 130 ° C., cooled and coarsely pulverized. After that, jet mill (made by Nippon Pneumatic,
Finely pulverized with a lab jet) to have an average particle size of about 8-12μ
m toner powder was obtained. Further, this toner powder is classified by a classifier (MDS-2, manufactured by Nippon Pneumatic Co., Ltd.),
Toner fine powder having an average particle diameter of about 10 μm was obtained. To 100 parts by weight of this toner fine powder, 2 parts by weight of hydrophobic silica (R972 manufactured by Nippon Aerosil Co., Ltd.) was uniformly mixed (externally added) to produce a toner.

(Evaluation) The following evaluations were performed using the toner resins and toners obtained in the examples. The results are shown in Table 1.

[Weight Average Molecular Weight] Gel Permeation Chromatography Measuring Device (HTR manufactured by Japan Millipore Limited)
-C) and two columns connected in series (Showa Denko KK, H
FIP-806M) was used to measure the weight average molecular weight of the crystalline polyester resin. The temperature is 40 ℃,
As a sample, a 0.45 μm filter was used to pass 0.
1% by weight hydroxyfluoroisopropanol solution
00 μL was injected, and hydroxyfluoroisopropanol containing 0.68 g of sodium trifluoroacetate per liter was used as a carrier solvent. Standard polystyrene was used as a calibration sample.

[Crystal melting point (Tm)] Using a differential scanning calorimeter (DSC-6200R, manufactured by Seiko Instruments Inc.),
The melting peak temperature of the crystalline polyester resin was determined based on JIS K 7121 and was used as the crystalline melting point Tm.
The sample mass was 10 mg, and the temperature rising rate was 10 ° C./min.

[Color tone] The color of the toner resin was visually observed.

[Blocking] 10 g of toner 100 m
After being placed in a L sample bottle and left in a constant temperature bath at 50 ° C. for 8 hours, it was sieved with a 250 μm filter using a powder tester (manufactured by Hosokawa Micron Co.) to observe whether aggregates remained on the filter.

[Fixing Evaluation] The toner is fixed on the printing paper by using a preheating device for preheating the printing paper on which the toner is transferred and an oven fixing type printing machine equipped with a fixing oven whose temperature is set to 140 ° C. It was When the printing surface of this printing paper was rubbed with an eraser to observe whether the printing surface was thinned, the image on the printing surface showed almost no change.

[0033]

[Table 1]

[0034]

According to the present invention, it is possible to provide a toner resin which exhibits sharp melting characteristics at a low temperature, is not colored and is excellent in blocking resistance. The toner for non-contact fixing method using the resin for toner can fix at a low temperature, which is difficult with the conventional toner, so that the fixing device can be simplified and power consumption can be reduced, and good color development can be achieved. As a possible color toner, it can be suitably used for a mono-color and full-color high-speed printing machine.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H005 AA01 CA08 EA03 EA06 FB01                 4J029 AA03 AB07 AD01 AD07 AE11                       AE18 BD04A BD07A BD10                       BF17 BF24 CA02 CA04 CA06                       CB04A CB05A CB06A CC05A                       CD03 GA13 GA14 GA17 HB01                       HB02 HB03A HB06

Claims (7)

[Claims] 1. A resin for toner comprising a crystalline polyester resin obtained by polymerizing a cycloaliphatic dialcohol and a dicarboxylic acid. 2. The resin for toner according to claim 1, wherein the dicarboxylic acid is an aliphatic dicarboxylic acid. 3. The toner resin according to claim 1, wherein the dicarboxylic acid is a linear aliphatic dicarboxylic acid. 4. The resin for toner according to claim 1, 2 or 3, wherein the dicarboxylic acid has 4 to 10 carbon atoms. 5. The resin for toner according to claim 1, 2, 3 or 4, wherein the crystalline polyester resin has a weight average molecular weight of 2,500 to 50,000. 6. The resin for toner according to claim 1, which contains an amorphous polyester resin having a glass transition temperature of 50 ° C. or higher. 7. A toner for a non-contact fixing method comprising the resin for toner according to claim 1, 2, 3, 4, 5 or 6.