JPH09127731A - Electrophotographic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner having excellent low temp. fixing property and offset resistance which can be fixed at low fixing temp. and shows excellent fixing strength to a transfer paper by incorporating a specified vicinal dicarboxylic acid monoester as a binder resin. SOLUTION: This toner contains a vicinal type dicarboxylic acid monoester expressed by formula I as a binder resin. In formula I, R<1> and R<2> may be same or different and are hydrogen atoms, 1-5C alkyl groups, 6-11C aryl groups or aralkyl groups, EX is a polyol residue having a polyether skeleton of bivalent phenol expressed by formula II or III, and WX is a polyolefin residue grafted with maleic acid anhydride. In formula II and formula III, two R<3> may be same or different and are 1-30C alkylidene groups which may have alcohol-type hydroxyl groups, R<4> and R<5> may be same or different and are hydrogen atoms, methyl groups or ethyl groups, R5 may be same or different, and n is an integer 1 to 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner, and more particularly to an electrophotographic toner which is excellent in low-temperature fixing property and anti-offset property and is suitable as a toner for a copying machine or a printer adopting heat roll fixing. .

[0002]

2. Description of the Related Art In copiers, printers and the like, there are a wet developing system and a dry developing system as a system for converting a latent image formed on a photosensitive material by exposure into a visible image. In the dry development method, the toner is usually charged by friction with the carrier, which is attached to the electrostatic latent image on the photosensitive drum by an electric attraction, and then transferred onto the paper and fixed by a heat roll or the like. It is converted into a permanent visible image. As a fixing method, a heating roller surface coated with a surface layer of a material having releasability for toner,
A heating roller method is often used in which a toner image on a sheet to be fixed is passed while being pressed and brought into contact therewith.

By the way, in recent years, with the spread of electrophotographic copying machines and printers in general households and the like, lower energy consumption (reduction of power consumption) when copying machines or printers is operated, and copying speed is increased. In order to increase the speed or reduce the machine cost, it is desired to reduce the roll pressure for simplifying the heat fixing roll. Further, due to the widespread use of copiers equipped with a double-sided copy function and an automatic document feeder for the purpose of increasing the quality of copiers, electrophotographic toner used in copiers and printers has a low fixing temperature. It is required to have excellent offset resistance and fixing strength on transfer paper. Therefore, from the viewpoint of low temperature fixability, a method using a low molecular weight resin for toner has been proposed. However, according to these methods, although the fixing property of the toner is certainly improved, a part of the toner forming an image at the time of fixing is transferred to the surface of the heat roller and is re-applied to the paper fed next. There is a problem that a phenomenon (offset) in which toner migrates and stains an image is likely to occur.

On the other hand, conventionally, various methods have been studied in order to prevent the toner from adhering to the surface of the heat roller used in the pressure heating method. For example, the surface of the heat roller is coated with a material having excellent releasability for the toner (for example, a fluororesin), and liquid such as silicone oil is used for the purpose of preventing offset and reducing fatigue of the heat roller surface. It has been practiced to coat the roller surface with a release material. However, this method is extremely effective in preventing the offset phenomenon, but it requires a separate device for supplying the liquid for offset prevention, which complicates the fixing device or causes oil to adhere to the copy. However, there is a problem in that handling may be hindered, and particularly when copying on an OHP or the like, the phenomenon becomes remarkable. Therefore, it is desired to develop a toner having a wide fixing temperature range and excellent anti-offset property without using these liquid release materials.

Therefore, at present, the offset phenomenon is prevented by adding a small amount of wax such as low molecular weight polyethylene (PE) or propylene (PP), which can be sufficiently melted in pressure heating in most copying machines, to the toner. doing. However, although the method using wax has some effect in preventing offset,
When the binder is a polyester resin, the compatibility with the PP wax is poor, and especially for full-color use, the hue of the toner image is deteriorated, and the charging characteristics become unstable. In addition, as another method for preventing the offset phenomenon, various methods for improving the binder resin constituting the toner have been tried. For example, there is known a method of improving the melt viscoelasticity of the toner by increasing the glass transition temperature (Tg) or the molecular weight of the binder resin.

[0006]

However, when the offset resistance is imparted by such a method, there arises a new problem that the fixability at low temperature (that is, the low temperature fixability) is deteriorated. On the other hand, in order to improve the low-temperature fixability of the toner, it is necessary to lower the viscosity of the toner at the time of melting, so it is required to lower the Tg and molecular weight of the binder resin. As described above, the properties of low-temperature fixing property and anti-offset property generally exhibit contradictory aspects, which makes it extremely difficult to develop a toner that simultaneously satisfies the two properties.

Under such a background, a binder excellent in offset resistance in a wide fixing temperature range and excellent in fixability at low temperature without applying a liquid release agent such as silicone oil to the fixing roller. The advent of resins is strongly desired.

Therefore, an object of the present invention is that it is excellent in low-temperature fixing property and anti-offset property, can be fixed at a low fixing temperature, does not cause any practical problem in the anti-offset property, and is fixed to a transfer paper. An object is to provide an electrophotographic toner having excellent strength.

[0009]

In order to solve the above problems, the present invention provides a binder resin represented by the following general formula (a):

[0010]

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(Wherein R ¹ and R ^{2, which} may be the same or different, are a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 11 carbon atoms or an aralkyl group, and EX is , The general formula (b1) or (b2):

[0012]

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(In the formula (b1) or (b2), two R
³ may be the same or different, is an alkylidene group having 1 to 30 carbon atoms, R ³ may have an alcoholic hydroxyl group, and R ⁴ and R ⁵ may be the same or different. It is a hydrogen atom, a methyl group or an ethyl group, and n is an integer of 1 to 10) and is a polyol residue having a polyether skeleton of a dihydric phenol, and WX is a maleic anhydride graft. The present invention provides an electrophotographic toner containing a vicinal type dicarboxylic acid monoester represented by the formula (1).

The electrophotographic toner of the present invention will be described in detail below.

The electrophotographic toner of the present invention contains the vicinal type dicarboxylic acid monoester represented by the general formula (a) as a binder resin. The above general formula (a) representing a vicinal type dicarboxylic acid monoester
In the above, R ¹ and R ² may be the same or different and each is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a carbon atom having 6 carbon atoms.
To 11 aryl groups or aralkyl groups. Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a neopentyl group, and the like. Examples of the aryl group of to 11 include a phenyl group, a tolyl group, a cumyl group, a naphthyl group and the like. Examples of the aralkyl group having 6 to 11 carbon atoms include benzyl group, α-phenethyl group, β-phenethyl group and the like.

In the general formula (a), EX
Is a polyol residue having a polyether skeleton of a dihydric phenol represented by the general formula (b1) or (b2). In the general formula (b1) or (b2),
The two R ^{3 s} may be the same or different and have 1 to 1 carbon atoms.
30 is an alkylidene group, R ³ may have an alcoholic hydroxyl group, and R ⁴ and R ⁵ may be the same or different and each is a hydrogen atom, a methyl group or an ethyl group. Examples of the alkylidene group having 1 to 30 carbon atoms include those having a structure represented by the following formula.

[0017]

[Chemical 6]

[0018]

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Further, n is an integer of 1-10.

Further, WX represents a maleic anhydride grafted polyolefin residue, and as will be described later, a polyolefin such as a homopolymer of ethylene or propylene, or a copolymer of ethylene or propylene with another α-olefin is anhydrous. Maleic anhydride obtained by reacting with maleic acid or its derivative is a grafted polyolefin residue. Other α-olefins include, for example, 1-butene, 1-hexene,
An α-olefin having 4 to 12 carbon atoms such as 4-methyl-1-pentene is preferable.

The vicinal type dicarboxylic acid monoester represented by the general formula (a) is produced by grafting a maleic anhydride grafted polyolefin with the following general formula (c):

[0022]

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It can be carried out by addition reaction with a polyol represented by the formula (1) in the presence of a catalyst. In the general formulas (c1) and (c2), R ³ , R ⁴ , R ⁵ and n are the same as those in the general formula (b1) or (b2).

As the maleic anhydride grafted polyolefin, a polyolefin represented by the general formula (d):

[0025]

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Examples of the maleic anhydride or its derivative represented by: those obtained by grafting in the presence of peroxide. In the general formula (d), R
¹ and R ² are the same as R ¹ and R ² in the general formula (a).

In this maleic anhydride grafted polyolefin, the content of maleic anhydride is usually
It is 0.1 to 20% by weight, preferably 1 to 10% by weight, based on the polyolefin serving as the substrate.

Further, the maleic anhydride grafted polyolefin is Mn from the viewpoint of compatibility with the polyolefin which is separately added as a releasing agent to the electrophotographic toner.
Those having a (number average molecular weight) of 200 to 10,000 and Mw (weight average molecular weight) of 300 to 50,000 are used, and those having a Mw of 500 to 30,000 are preferably used.

In the present invention, as a specific example of this maleic anhydride grafted polyolefin, modified polyethylene # 2203 marketed by Mitsui Petrochemical Co., Ltd.
A, # 220MP, # 4202E, 2203A, modified polypropylene # NP0555A, # EP014, etc. can be illustrated.

The polyol represented by the general formula (c) is not particularly limited and is usually produced by the following production method (A) or production method (B).

Process (A) : The following formula (e) obtained from dihydric phenols and epichlorohydrin:

[0032]

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The polyol represented by the above general formula (c) can be produced by the addition reaction of the bisphenol type epoxy resin represented by the formula (1) and a polyalcohol having at least two primary alcoholic hydroxyl groups in the molecule. it can. In the formula (e), R ⁴ and R ⁵ are the same as those in the general formula (b1) or (b2), and m is 0 to 9
Is an integer. The bisphenol-type epoxy resin represented by the formula (e) is excellent in blocking resistance, has a viscosity in the proper range when melted, and provides an electrophotographic toner having excellent low-temperature fixability. Molecular weight (Mn)
Is preferably 800 to 8000, particularly 150
It is preferably 0 to 6000. Examples of the polyalcohol include ethylene glycol, diethylene glycol, propylene glycol, glycerol,
1,4-butanediol, trimethylolpropane, pentaerythritol, sorbitol, polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.0)-
Examples thereof include alkylene oxide adducts of bisphenol A such as 2,2-bis (4-hydroxyphenyl) propane.

In this addition reaction, a catalyst can be usually used in order to allow the reaction to proceed efficiently. Examples of the catalyst used include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, lithium halides such as lithium chloride and lithium bromide, and alkali metal such as sodium methoxide and sodium ethoxide. Alkyl metal salts of carboxylic acids such as alkoxides and sodium stearate, ammonium salts such as tetramethylammonium chloride and benzyltriethylammonium chloride, boron trifluoride / ether complex, tin tetrachloride, tin acetate, titanium tetrabutoxide, zirconium acetate, etc. Examples thereof include Lewis acids, phosphoric acid, sulfuric acid, benzenesulfonic acid, and protonic acids such as tetrafluoroboric acid.

A solvent can be used in the above addition reaction. Preferred solvents include aromatic hydrocarbons such as toluene, xylene and ethylbenzene, 2
-Hydroxy-3-methoxypropane, 2-hydroxy-3-ethoxypropane, 2-hydroxy-3-butoxypropane, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, glycol compounds such as diethylene glycol dimethyl ether, tetrahydrofuran, 1,4-dioxane, etc. And cyclic ketones such as 2-butanone and 4-methyl-2-pentanone.

This addition reaction is usually completed in the presence of the above catalyst at a reaction temperature of 70 to 170 ° C. for 1 to 15 hours. Further, in this addition reaction, the equivalent ratio of the primary alcoholic hydroxyl group and the epoxy group is 1: 0.5 to 1: 1.5,
It is preferably 1: 0.7 to 1: 1.3, and the epoxy equivalent of the addition reaction product is 5000 g / eq or more, preferably 10000 g / eq or more.

Process (B) : The following general formula (f) obtained from dihydric phenol and epichlorohydrin:

[0038]

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A hydroxyl group-terminated phenolic resin having phenolic hydroxyl groups at both ends represented by the following formula (g):

[0040]

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The polyol represented by the above general formula (c) can be produced by an addition reaction with glycidol represented by or its self-polymerization product. In the general formula (f), R ⁴ and R ⁵ are the same as those in the general formula (c), and k is an integer of 1 to 10. Moreover, in Formula (g), j is an integer of 0-20.

The hydroxyl group-terminated phenolic resin represented by the general formula (f) has excellent blocking resistance, has a viscosity in the proper range when melted, and provides an electrophotographic toner having excellent low-temperature fixability. It is preferable that the number average molecular weight (Mn) is 800 to 8000, and particularly 1500 to 6
000 is preferred.

In this addition reaction, glycerol-α-monochlorohydrin is used in the presence of an equimolar amount of an aqueous sodium hydroxide solution instead of glycidol or its self-polymerization product, and glycidol or its self-polymerization is carried out in the reaction system. It is also possible to generate a substance to proceed the addition reaction.

In the production method (B), a catalyst can be usually used in order to promote the addition reaction efficiently. Examples of the catalyst to be used include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, lithium halides such as lithium chloride and lithium bromide, tetramethylammonium chloride and benzyltriethylammonium chloride. An ammonium salt etc. can be illustrated.

At the time of this addition reaction, it is also possible to use the solvents exemplified in the production method (A). Furthermore, the addition reaction is usually carried out at a reaction temperature of 70 to 1 in the presence of the above catalyst.
It is completed in 30 minutes to 12 hours at 60 ° C.

The electrophotographic toner of the present invention requires the vicinal type dicarboxylic acid monoester represented by the above general formula (a) as a binder resin, a charge control agent, a colorant, a release agent, and magnetic powder. The particles are composed of a composition obtained by appropriately dispersing and mixing the components to be blended accordingly, and have an average particle diameter in the range of 5 to 20 μm.

The charge control agent to be used can be appropriately selected depending on whether the toner for electrophotography of the present invention is used as a positively charged toner or a negatively charged toner, or its application. When the electrophotographic toner of the present invention is a positively charged toner, a conventionally known positively chargeable charge control agent is used. For example, electron donating dyes typified by nigrosine dyes, imidazole derivatives, alkoxylated amines, triphenylmethane derivatives, quaternary ammonium salts, alkylamides, simple substances of phosphorus or tungsten and their compounds, molybdic acid chelate pigments, etc. Can be mentioned. When the electrophotographic toner of the present invention is a negatively charged toner, a conventionally known negatively chargeable charge control agent is used. Examples thereof include electron-accepting dyes such as metal complex salts of monoazo dyes, chlorinated polyolefins, sulfonylamines of copper phthalocyanine, oil black, metal salts of naphthenic acid, metal salts of fatty acids, and the like.

The colorant used in the present invention is not particularly limited, and a commonly used colorant is used. For example, when preparing a black electrophotographic toner, there is no particular limitation, and a conventionally known black colorant can be used. Specific examples include pigments such as carbon black and grafted carbon black whose surface is chemically treated. Further, in the case of preparing an electrophotographic toner other than black, for example, an electrophotographic toner of three primary colors of yellow, magenta or cyan, conventionally known colorants can be used, respectively, and there is no particular limitation. For example, as a colorant used when preparing a yellow electrophotographic toner, chrome yellow, quinoline yellow, etc. may be mentioned. Examples of the colorant used when preparing the magenta electrophotographic toner include DuPont Oil Red and Rose Bengal. Examples of colorants used when preparing a cyan electrophotographic toner include aniline blue, methylene blue chloride, phthalocyanine blue, and the like. When these colorants are blended in the electrophotographic toner of the present invention, the blending amount thereof is about 0.01 to 20% by weight, preferably about 1 to 10% by weight based on the total amount of the toner.

Further, as a releasing agent blended for the purpose of improving the releasing property of the electrophotographic toner of the present invention, for example, low molecular weight polypropylene, low molecular weight polyethylene, fatty acid, fatty acid metal salt, fatty acid ester, partially saponified. Examples thereof include fatty acid ester, higher alcohol, paraffin wax, amide wax, silicone oil, etc.
They may be used alone or in combination of two or more.
When a release agent is blended with the electrophotographic toner of the present invention, the blending amount is 0.5 to 10 relative to the total amount of the binder resin.
It is the amount that becomes the weight%.

When the electrophotographic toner of the present invention is a magnetic toner which is a one-component type developer, magnetic powder is mixed. Examples of the magnetic powder used include those made of iron oxides such as ferrite and magnetite, and metals such as iron, cobalt, and nickel. These may be used alone or in combination of two or more. The magnetic powder is preferably a fine powder having a particle size of 1 μm or less.
When the magnetic powder is blended in the electrophotographic toner of the present invention, the blending amount is 30 to 300 with respect to the total amount of the binder resin.
It is the amount that becomes the weight%.

Further, the electrophotographic toner of the present invention comprises
If necessary, a fluidity improver can be added.
Examples of the fluidity improver used include hydrophobic silica fine powder, alumina, titanium oxide, silica sand, mica, etc. These may be used alone or in combination of two kinds. Among these, hydrophobic silica is particularly preferable. When the fluidity improver is blended with the electrophotographic toner of the present invention, the blending amount is 0.01 to 1.0% by weight based on the total amount of the binder resin.

[0052]

In the present invention, the vicinal type dicarboxylic acid monoester represented by the general formula (a) is used with a wax such as low molecular weight polyethylene (PE) or propylene (PP) which is a general-purpose releasing agent. Excellent compatibility, lowering the melting start temperature improves low-temperature fixability, and at the same time,
Since many alcoholic hydroxyl groups present in the binder resin skeleton strongly interact with the cellulose forming the paper, it is considered that an electrophotographic toner excellent in fixing strength with the paper can be obtained.

[0053]

EXAMPLES The present invention will be specifically described below with reference to examples of the present invention and comparative examples, but the present invention is not limited to these examples. In addition, property measurements and performance evaluations in Synthesis Examples, Examples and Comparative Examples were performed according to the following methods.

(1) Epoxy equivalent (g / eq) 0.2 to 5 g of a sample is precisely weighed and put in a 200 ml Erlenmeyer flask, and then 25 ml of dioxane is added and dissolved.
Next, 1 / 5N hydrochloric acid solution (solvent: dioxane) 25
Add ml, stopper tightly, mix well, and let stand for 30 minutes. Toluene-ethanol mixed solution (volume ratio: 1:
1) After adding 50 ml, titrate with 1/10 N sodium hydroxide aqueous solution using cresol red as an indicator.
The epoxy equivalent (g / eq) is calculated according to the following formula based on the obtained titration result. Epoxy equivalent (g / eq) = 1000 × W / [(B-
S) × N × F] W: Sampling amount (g) B: 1/10 N aqueous sodium hydroxide solution (ml) required for blank test S: 1/10 N aqueous sodium hydroxide solution required for sample test ( ml) N: normality of aqueous sodium hydroxide solution F: titer of 1/10 normal aqueous sodium hydroxide solution

(2) Number average molecular weight (Mn) by GPC
And 80 mg of the measurement sample of the weight average molecular weight (Mw)
Dissolve in 10 ml of HF to prepare a sample solution. Using 30 μl of this sample solution, the elution peak curve is measured using GPC having the following constitution, and the molecular weight is calculated based on the calibration curve prepared in advance. The calibration curve is prepared using polystyrene having a known average molecular weight as a standard substance. In addition, the columns and configuration used are as follows.・ Column configuration: GLR-400M + GLR-400M + GLR-400 (all manufactured by Hitachi Chemical Co., Ltd.) ・ Column temperature: 40 ° C ・ Mobile phase (flow rate): THF (1 ml / min) ・ Peak detection method: UV (254 nm)

(3) Tg (glass transition temperature) It is measured under the following conditions using the following differential scanning calorimeter.・ Differential scanning calorimeter: SEIKO 1 DSC200 SEIKO 1 SSC5040 (Disk Station) ・ Measurement conditions: Temperature range: 25 to 200 ° C. Temperature rising rate: 20 ° C./min Sampling time: 0.5 sec Sample amount: 10 mg

(4) Flow softening temperature (Tm) (° C.) Using a flow tester (CFT500A, manufactured by Shimadzu Corporation), nozzle diameter 1.0 mm × length 1.0 mm, measuring load: 20 kg, heating rate: Under the conditions of 6 ° C./min, temperature rising start temperature: 60 ° C., sample amount: 1.0 g, the temperature when half the sample flows out is measured as Tm.

(5) Softening point (SP) Using a METTLER FP90, the softening temperature of the sample is measured at a temperature rising rate of 1 ° C./min.

(6) Hydroxyl value 1.5 to 2.0 g of a sample was precisely weighed and put in a 25 ml volumetric flask, and about 15 ml of purified chloroform from which ethanol and water were removed by filtration with a molecular sieve 4A was added and completely dissolved. After that, add more purified chloroform to add 25
The sample line was adjusted to the mark line of ml. Next, the sample solution
Transfer to a cell for KBr liquid (thickness: 0.2 mm), using purified chloroform as a control solution, wave number 3000 to 4000 cm ^-1.
The absorbance at is measured. The absorbances T ₁ and T ₂ of the _two absorption peaks appearing in the obtained absorbance curve are determined with the absorbance of the control solution as the zero standard. Next, based on the calibration curve prepared in advance, the hydroxyl group concentration (eq / l) was calculated from the value of T ₁ + T ₂ , and the hydroxyl value was calculated according to the following formula. Hydroxyl value (mg / g) = [(hydroxyl group concentration / 4) × 56.
1 × F] / sample weight × 100 where F: cell thickness correction coefficient (L ₁ + L ₂ ) L ₁ : cell thickness (mm) at the time of creating a calibration curve L ₂ : cell used for measuring absorbance Thickness (mm)

(7) Amount of phenolic hydroxyl group 10 g of a sample was precisely weighed and put in a 100 ml measuring flask,
Add 50 ml of dioxane and dissolve. After completely dissolving, dioxane was further added to adjust to a 100 ml marked line to prepare a sample solution. 50 ml of this sample solution 5 ml
Add 5 ml of dioxane to the beaker to bring the total volume to 1
Make it 0 ml. Then, 2 ml of a 0.5% by weight solution of 3-methyl-2-benzothiazolinonehydrazine in methanol,
And 0.4 ml of 25 wt% ammonia water and 2 ml of 2 wt% potassium ferricyanide aqueous solution were sequentially added, and then 3
Leave for 0 minutes. The absorbance of the sample solution obtained by filtering the insoluble matter with a filter paper (No. 5C) is measured using a spectrophotometer (wavelength 510 nm, cell volume 10 ml). In addition, a blank test is also performed on a blank solution obtained by performing the same operation without adding a sample. The amount of phenolic hydroxyl groups in the sample is calculated in terms of bisphenol A from the absorbance calibration curve prepared in advance using bisphenol A as a standard substance.

(8) Acid value 10 to 20 g of a sample is precisely weighed and put in a 200 ml Erlenmeyer flask, and 40 ml of 99.5 wt% ethanol is added and dissolved to prepare a sample solution. 1% by weight of this sample solution was used as an indicator to prepare a 1% by weight phenolphthalein aqueous solution.
Titrate with 10N sodium hydroxide solution. The acid value is calculated according to the following formula based on the titration result. Acid value (mgKOH / g) = (5.610 × V × N × F)
/ W W: sampled amount (g) S: 1/10 normal sodium hydroxide aqueous solution (ml) required for sample titration N: normality of sodium hydroxide aqueous solution F: titer of 1/10 normal sodium hydroxide aqueous solution

(9) Blocking resistance In a glass cylindrical container having a diameter of 5 cm and a height of 15 cm.
Toner powder 50cm ^ThreeCharged with a diameter of 5c
A weight of 500 g is applied using a SUS weight of m. Humidity 60%
After leaving it for 2 days in an atmosphere of RH and temperature of 40 ° C,
Let stand at room temperature for 3 hours. After removing the weight, the powder
Ease of powder flow when the contained glass container is tumbled horizontally
Was visually observed. The evaluation criteria are as follows.
is there. ◎; All toner powder flows out just by turning the container upside down.
You. ○; 30% or more by turning the container upside down and shaking it lightly
Toner powder flows out. △; About 70% of toner powder even when the container is upside down and shaken lightly
The powder remains in the container. ×; More than half the toner even when the container is upside down and shaken lightly
The powder remains in the container.

(Synthesis Example 1) Production Example of Polyol Represented by General Formula (c) (Production Method A) -In a separable flask having a capacity of 2 liters, equipped with a stirrer, a thermometer, a nitrogen inlet, and a cooling tube, Bisphenol A type epoxy resin (Mitsui Petrochemical Industry Co., Ltd., Epomic R304, epoxy equivalent: 906 g / eq, softening point: 9
(2 ° C.) 1090 g, glycerol 111 g, and propylene glycol monomethyl ether 300 g were charged, and the temperature was started to be raised in a nitrogen atmosphere until the internal temperature reached 80 ° C. Next, 4.8 ml of fluoroboric acid (concentration 4.2%) as a reaction catalyst was added, the temperature was further raised, and stirring was continued while maintaining the internal temperature at 120 ° C. During the reaction, the amount of epoxy groups in the reaction mixture was measured at regular intervals, and the epoxy equivalent was 200 in 5 hours.
It was confirmed to be 00 g / eq or more, and it was confirmed that the epoxy group had substantially disappeared. At this time, 4.6 ml of 0.2N sodium hydroxide aqueous solution was added to the system, and the system was immediately depressurized to remove propylene glycol monomethyl ether as a reaction solvent and a small amount of water remaining in the system.
Next, after maintaining at 150 ° C. and 10 mmHg for 2 hours, the produced molten polyol was taken out from the flask.

The obtained polyol has a softening point (SP):
118 (° C.), epoxy equivalent: 20000 g / eq or more, number average molecular weight (Mn): 2350, weight average molecular weight (Mw): 5400, and Mw / Mn: 2.3. Hereinafter this polyol is referred to as (P-1).

(Synthesis Example 2) Production Example of Polyol Represented by General Formula (c) (Production Method) -Bisphenol was placed in a separable flask having a capacity of 1 liter equipped with a stirrer, a thermometer, a nitrogen inlet, and a cooling tube. 188 g of A-type liquid epoxy resin (Mitsui Petrochemical Co., Ltd., Epomic R140P, epoxy equivalent: 188 g / eq, viscosity: 13500 mPa · s), 173 g of bisphenol A, and 70 ml of xylene were charged, and heating started under a nitrogen atmosphere. Then, when the internal temperature reached 80 ° C, 2.82 ml of 0.5% tetramethylammonium chloride aqueous solution was added, and the temperature was further raised to an internal temperature of 130 ° C.
When the temperature reached, the reaction system was depressurized and xylene and water were extracted out of the system. The reaction was carried out while maintaining the reaction temperature at 130 ° C., and after 1 hour, nitrogen was introduced and the pressure was returned to normal pressure. During the reaction, the amount of epoxy groups in the reaction mixture was measured at regular intervals, and the reaction was continued with stirring. When the temperature reached 130 ° C., 5 hours later, the epoxy equivalent of the reaction mixture was reached. Is 20000 g / eq
That's it. Then, the reaction was terminated to obtain a hydroxyl group phenol-terminated resin. The hydroxyl group-terminated phenolic resin thus obtained has a softening point of 106 ° C. and a hydroxyl value of 280 KOHmg.
/ G, Mn by GPC: 2270, Mw: 4670,
And Mw / Mn: 2.1.

Next, the hydroxyl group-terminated phenolic resin obtained above was cooled to 80 ° C., and then 400 g of 2-butanone was added.
Was added to form a uniform solution. Then, when the internal temperature reached 70 ° C., 190.8 g of glycidol was added to the solution, and the temperature was maintained to continue the reaction. During the reaction, the amount of phenolic hydroxyl groups remaining in the reaction mixture was measured at regular intervals. As a result, it was confirmed that the amount of phenolic hydroxyl group in the system was 100 wtppm (converted to bisphenol A) or less after 4 hours. After that, 300 ml of water was added to the system, followed by washing with water at 70 ° C. for 30 minutes and leaving it to stand. Then, after extracting the lower water layer part,
The same operation was repeated once for the oil layer portion. Then, in a reduced pressure atmosphere, the oil layer portion was gradually heated to distill away 2-butanone. After maintaining the state of 10 mmHg at the system temperature of 150 ° C. for 1 hour, the generated hydroxyl group-terminated phenolic resin was taken out of the system.

The hydroxyl group-terminated phenol resin thus obtained had a softening point (SP) of 113 ° C., a Tg (DSC) of 57 ° C., an epoxy equivalent of 20000 g / eq or more, and a Mn of 241.
0, Mw: 5980, and Mw / Mn: 2.5. Hereinafter, this hydroxyl group-terminated phenol resin (polyol resin) is referred to as (P-2).

(Synthesis Example 3) Synthesis of vicinal type dicarboxylic acid monoester (E-1) from (P-1) and maleic anhydride grafted polyolefin equipped with a stirrer, thermometer, nitrogen inlet, and cooling pipe. In a 500 ml separable flask, 200 g of the polyol (P-1) obtained in Synthesis Example 1 and maleic anhydride-grafted polypropylene (manufactured by Mitsui Petrochemical Industry Co., Ltd., N
PO555A, weight average molecular weight: 17700, maleic anhydride content: 4.3% by weight (6 g), and toluene (200 ml) were charged, and the mixture was slowly stirred at about 50 ° C. to give a uniform solution. At the same temperature, titanium tetbutoxide 0.
After adding 1 ml, the temperature was gradually raised to 120 ° C.
While agitating continuously at the same temperature, a part of the reaction mixture was sampled at regular intervals and the infrared absorption spectrum was measured to track the degree of decrease in absorption at a wave number of 1780 cm ^-1 based on the maleic anhydride group. did. As a result, after 4 hours, in the infrared absorption spectrum, the absorption peak is almost disappeared, a new wave number 1700 cm ^-1 and 1740 cm ^-1, absorption peaks respectively based on carboxylic acid and ester bond was observed. Here, the maleic anhydride concentration and the wave number 1 based on the maleic anhydride group
From the calibration curve prepared in advance for the intensity of the absorption peak appearing at 780 cm ⁻¹ , it was found that 79% of the maleic anhydride group was ring-opened to form a vicinal dicarboxylic acid monoester. Then, the system was depressurized to distill off the reaction solvent xylene. 10 mm at system temperature of 130 ° C
After maintaining the Hg state for 30 minutes, the generated vicinal dicarboxylic acid monoester in a molten state was extracted out of the system.

The resulting vicinal dicarboxylic acid monoester had a softening point (SP) of 121 ° C. and a number average molecular weight (M
n): 2430, weight average molecular weight (Mw): 5900,
It had a Mw / Mn of 2.4, an acid value of 5 (KOHmg / g), and a hydroxyl value of 260 (KOHmg / g). Hereinafter, this vicinal type dicarboxylic acid monoester is referred to as (E-1).

(Synthesis Example 4) Synthesis of vicinal type dicarboxylic acid monoester (E-2) from (P-2) and maleic anhydride grafted polyolefin As a polyol, (P-2) instead of (P-1) Two
0 g, instead of maleic anhydride grafted polypropylene (NPO555A, manufactured by Mitsui Petrochemical Co., Ltd.),
Maleic anhydride grafted polyethylene (Mitsui Petrochemical Co., Ltd., 2203A, weight average molecular weight: 270)
0, maleic anhydride group content: 3.2% by weight) The reaction was performed in the same manner as in Synthesis Example 3 except that 5 g was used. As a result, it was found that 86% of the maleic anhydride group was ring-opened to form a vicinal type dicarboxylic acid monoester after a reaction time of 6 hours. The reaction solvent was removed to obtain a vicinal dicarboxylic acid monoester.

The obtained vicinal type dicarboxylic acid monoester had a softening point (SP): 123 (° C.), a number average molecular weight (Mn): 2595, and a weight average molecular weight (Mw): 740.
0, Mw / Mn: 2.9, acid value: 3 (KOHmg /
g), and hydroxyl value = 310 (KOHmg / g). Hereinafter, this vicinal type dicarboxylic acid monoester is referred to as (E-2).

Example 1 180 g of the vicinal dicarboxylic acid monoester (E-1) obtained in Synthesis Example 3, 4 g of nigrosine dye (N-04 manufactured by Orient Chemical Co., Ltd.), carbon black (MA-100 manufactured by Mitsubishi Chemical Co., Ltd.) ), And 6 g of polypropylene wax (Viscole 660P manufactured by Sanyo Kasei Co., Ltd.) were mixed with a small pulverizing mixer (manufactured by Kyoritsu Riken, sample mill), and then melt-kneaded with a two-roll to prepare a composition. After cooling, the composition was crushed with a jet mill,
The particles were classified by a dry airflow classifier to obtain composition particles having an average particle size of 10 μm. After that, it was 0.
3 g of hydrophobic silica (R972 manufactured by Nippon Aerosil Co., Ltd.) was mixed and stirred in a Henschel mixer for 30 seconds,
An electrophotographic toner was obtained. T of this electrophotographic toner
m, Tg and blocking property were measured or evaluated.

Next, 5 g of the electrophotographic toner and 95 g of an iron powder carrier having an average particle size of 60 to 100 μm are uniformly mixed to prepare a developer, and the fixing strength and the offset generation temperature are determined by the following method. It was measured. As the electrophotographic copying machine, Fuji Xerox 3500 manufactured by Fuji Xerox Co., Ltd. was modified so that the surface temperature of the fixing heat roller could be adjusted. The fixing strength was obtained from the density change of the copied image when the above-mentioned developer was used to make various copies on the surface of the roller for copying and the copied image was rubbed with an eraser. As for the offset generation temperature, the surface temperature of the roller was increased from 100 ° C. to 220 ° C. in steps of 10 ° C., and the temperature at which the fixing ratio exceeded 85% was taken as the minimum fixing temperature. Further, when the temperature was further raised, the temperature at which the molten toner began to adhere to the heat roller was taken as the high temperature offset start temperature. The region between the minimum fixing temperature and the high temperature offset start temperature was defined as the non-offset fixing temperature region. Table 1 shows the results.

Example 2 In the same manner as in Example 1 except that (E-2) obtained in Synthesis Example 4 was used as the vicinal type dicarboxylic acid monoester instead of (E-1). A toner for electrophotography was prepared to measure or evaluate Tm, Tg and blocking property, and a developer was prepared to measure fixing strength and offset generation temperature. Table 1 shows the results.

(Comparative Examples 1 and 2) In each of the examples, (P-1) or (P-2) was used instead of (E-1) or (E-2) as a binder. A toner was prepared in the same manner as in Example 1 to measure or evaluate Tm, Tg and blocking property, and further,
A developer was prepared and the fixing strength and the offset generation temperature were measured. Table 1 shows the results.

Comparative Example 3 (E-1) as a binder
In addition to using a commercially available polyester resin (NCP-001 manufactured by Nippon Carbide Industry Co., Ltd.) instead of, a toner was prepared in the same manner as in Example 1 to measure or evaluate Tm, Tg and blocking property, and further,
A developer was prepared and the fixing strength and the offset generation temperature were measured. Table 1 shows the results.

[0077]

[0078]

INDUSTRIAL APPLICABILITY The electrophotographic toner of the present invention is excellent in low-temperature fixing property and offset resistance, can be fixed at a low fixing temperature, and does not cause any problem in offset resistance in practical use. It has excellent fixing strength to.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Kobayashi 3 Chikusaigan, Ichihara, Chiba Mitsui Oil Chemicals Co., Ltd.

Claims (3)

[Claims] 1. A binder resin represented by the following general formula (a): (In the formula, R ¹ and R ² may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a carbon atom having 6 to 6 carbon atoms.
11 is an aryl group or an aralkyl group, and EX is
General formula (b1) or (b2): (In formula (b1) or (b2), two R ^{3 s} may be the same or different and each is an alkylidene group having 1 to 30 carbon atoms, and R ³ may have an alcoholic hydroxyl group. , R ⁴ and R ⁵ may be the same or different and each is a hydrogen atom, a methyl group or an ethyl group, and n is 1
It is a polyol residue having a polyether skeleton of a dihydric phenol represented by
An electrophotographic toner containing a vicinal type dicarboxylic acid monoester represented by maleic anhydride grafted polyolefin residue). 2. The toner for electrophotography according to claim 1, wherein the binder resin contains 0.5 to 15% by weight of the vicinal dicarboxylic acid monoester. 3. The vicinal dicarboxylic acid monoester represented by the general formula (a) has a weight average molecular weight of 500 to 500.
Maleic anhydride grafted polyolefin of 30,000 and the following general formula (c1) or (c2): (In formula (c1) or (c2), two R ^{3 s} may be the same or different and are alkylidene groups having 1 to 30 carbon atoms, and R ³ may have an alcoholic hydroxyl group. , R ⁴ and R ⁵ may be the same or different and each is a hydrogen atom, a methyl group or an ethyl group, and n is 1
The toner for electrophotography according to claim 1, which is an addition reaction product with a polyol represented by (an integer of 10 to 10).