JP2001109191A - Resin composition for toner and toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for a toner and a toner which have excellent fixing property, offset resistance, storage property and transparency and which do not cause fog due to production of fine powder in a developing machine. SOLUTION: The resin composition for a toner consists of a vinyl copolymer and an amorphous saturated polyester. The vinyl copolymer has the maxima at least in the region from 3×103 to 3×104 and from 2×105 to 2×106 in the mol.wt. distribution measured by gel permeation chromatography. The noncrystalline saturated polyester has 45 to 70 deg.C glass transition point, 85 to 105 deg.C flow softening point, and >=90 A hardness of measured by a durometer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for toner used in electrophotography and the like, and a toner.

[0002]

2. Description of the Related Art In electrophotography and the like, a dry developing method is often used as a method for developing an electrostatic image. In this method, usually, toner is charged by friction with ferrite powder, iron powder, glass beads, etc. called a carrier, and then adheres to an electrostatic latent image on a photoreceptor by electrostatic force to form an image. The image is transferred onto a sheet in contact with the rotating photoreceptor and fixed on the sheet by a heat roller or the like to form a permanent visible image.

A fixing method using a heat roller or the like is performed by passing a toner image of a sheet to be fixed on a surface of a heating roller having a surface formed of a material having releasability from toner while being in pressure contact therewith. The heating roller method is frequently used. In the heating roller method, a resin composition for a toner that can be fixed at a lower temperature is desired in order to improve economy such as power consumption and to increase copying speed.

[0004] Japanese Patent Application Laid-Open No. 7-36218,
No. 114942 discloses a method for improving the fixing property and the offset resistance by adding a low molecular weight or low viscosity ethylene-based wax.

However, in the above method, the dispersibility of the low-melting crystalline compound in the toner greatly affects the storage stability, and the content of the low-melting crystalline compound is reduced for the purpose of further improving fixability. When the content increases, the dispersed particle size of the low-melting crystalline compound becomes large, and there is a problem that storage stability is deteriorated.

As described above, even when the amount of addition is increased, the storage stability of the low melting point crystalline compound having a narrow allowable range of addition is relatively suppressed, and the balance between fixability and offset resistance is good. An example is an amorphous polyester.

Japanese Patent Application Laid-Open No. 2-277,074 proposes a toner mainly composed of a reaction product of an amorphous polyester resin and a vinyl copolymer resin. JP-A-6-194876 discloses a non-crosslinked resin having a high glass transition point and a non-crosslinked non-crosslinked resin having a low glass transition point obtained by polymerizing styrenes or styrenes and (meth) acrylates. A toner binder comprising a crystalline polyester and, if necessary, a compatibilizer has been proposed.

In the above-mentioned method, good low-temperature fixability is exhibited, and especially in the latter case, excellent storage stability is exhibited. However, in these methods, the amorphous polyester used has a number average molecular weight of about 1,000 to 5,000,
When the molecular weight is as low as 000, there is a problem that the resin strength is reduced, and fine powder is generated in the developing machine, so that fogging is likely to occur.

[0009]

SUMMARY OF THE INVENTION In view of the above, the present invention has excellent fixability, offset resistance, storage stability, and transparency.
It is an object of the present invention to provide a toner resin composition and toner that do not generate fog due to generation of fine powder in a developing machine.

[0010]

SUMMARY OF THE INVENTION The present invention provides a vinyl-based copolymer.
Resin for toner consisting of coalesced and amorphous saturated polyester
A composition, wherein the vinyl copolymer is a gel permeate.
Molecular weight measured by application chromatography
At least 3x10 in distribution^Three ~ 3 × 10 ^Four as well as
2 × 10^Five ~ 2 × 10⁶ Has a maximum value at
Japanese polyester has a glass transition point of 45 to 70 ° C.
Has a flow softening point of 85 to 105 ° C.
Resin set for toner with a meter hardness of A hardness of 90 or more
It is an adult. Hereinafter, the present invention will be described in detail.

The resin composition for toner of the present invention comprises a vinyl copolymer and an amorphous saturated polyester. The vinyl monomer constituting the vinyl copolymer is not particularly limited. For example, a styrene monomer, a (meth) acrylate monomer, acrylic acid, methacrylic acid,
(meth) acrylic acid such as α-ethylacrylic acid and crotonic acid or an α-alkyl derivative or β-alkyl derivative thereof; an unsaturated dicarboxylic acid such as fumaric acid, maleic acid, citraconic acid, and itaconic acid or a monoester derivative thereof; Diester derivatives; monoacryloyloxyethyl succinate, monomethacryloyloxyethyl succinate, acrylonitrile, methacrylonitrile, acrylamide and the like. this house,
As the vinyl monomer, a styrene monomer and a (meth) acrylate monomer are preferable.

The styrene monomer is not particularly restricted but includes, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethyl styrene,
pn-butylstyrene, pt-butylstyrene, p
-N-hexylstyrene, pn-octylstyrene,
pn-dodecylstyrene, p-methoxystyrene, p
-Phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene and the like. These may be used alone or in combination of two or more.

The (meth) acrylate monomer is not particularly restricted but includes, for example, methyl acrylate,
Ethyl acrylate, propyl acrylate, n-acrylate
-Butyl, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacryl Alkyl esters of (meth) acrylic acid such as n-octyl acid, dodecyl methacrylate, stearyl methacrylate;
2-chloroethyl acrylate, phenyl acrylate, α
-Methyl chloroacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, glycidyl acrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-methacrylic acid Examples include hydroxyethyl, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, glycidyl methacrylate, bisglycidyl methacrylate, polyethylene glycol dimethacrylate, methacryloxyethyl phosphate, and the like. Among them, 2-ethylhexyl acrylate, n-butyl acrylate, methyl methacrylate, n-butyl methacrylate and the like are preferable. These may be used alone or in combination of two or more.

In the present invention, the vinyl copolymer may have a crosslinked structure or may be a copolymer of a crosslinking agent. The crosslinking agent is not particularly limited, and examples thereof include divinylbenzene, ethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,5. -Pentanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate
Acrylate, tetraethylene glycol di (meth) acrylate, pentaethylene glycol di (meth) acrylate, polyethylene glycol # 200, # 40
Bifunctional ones such as 0, # 600 each of di (meth) acrylate, dipropylene glycol di (meth) acrylate, and polypropylene glycol di (meth) acrylate;
Pentaerythritol tri (meth) acrylate, trimethylolethanetri (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, oligoester (meth) acrylate, 2,2-bis (4- (Methacryloxypolyethoxyphenyl) propane, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, polyfunctional ones such as diarylchlorendate and the like. These may be used alone or in combination of two or more.

The above-mentioned vinyl copolymer is a gel permeate.
Measured by chromatography (GPC)
At least 3 × 10^Three ~ 3 × 10
^Four And 2 × 10^Five ~ 2 × 10⁶ Has a local maximum. in
Also, the above vinyl copolymer has a minimum maximum value of 3 × 10
^Three ~ 3 × 10^Four And the maximum value is 2 × 10^Five ~
2 × 10⁶ Is preferably in the range.
Minimum local maximum is 3 × 10 ^Three If the resin strength is less than
It becomes weak, and fine powder is generated in the developing machine and fog easily appears.
Becomes 3 × 10^Four If it exceeds, the fixability may decrease.
is there. The maximum value is 2 × 10^Five If less than
Fsetability may deteriorate, 2 × 10⁶ Exceeds
, The fixability may be reduced. In molecular weight distribution
If it has two maxima, it is usually low molecular weight and high molecular weight
It is not easily mixed with the body and becomes brittle, and fog tends to appear
However, since the present invention has the above-described configuration, both are good.
Is mixed.

The maximum value is calculated by a computer from the molecular weight distribution obtained by GPC. GPC usually uses HTR-C manufactured by Nippon Millipore Limited as an HPLC apparatus, and uses KK manufactured by Showa Denko as a column.
One F-800P, two KF-806M, KF-8
02.5 are connected in series. The measurement conditions were a temperature of 40 ° C. and a sample concentration of 0.2 wt% THF.
The solution is passed through a 0.45 μm filter and injected at an injection volume of 100 μL. Standard polystyrene is used as a calibration sample.

The flow softening point of the vinyl copolymer is as follows:
The temperature should be as low as possible, preferably 130 ° C or lower. When the temperature exceeds 130 ° C., the fixability of the obtained toner may be reduced. The above vinyl copolymer preferably has a glass transition point of 50 ° C. or higher. When the temperature is lower than 50 ° C., the storage stability of the obtained toner may be reduced.

The method for polymerizing the vinyl copolymer is not particularly limited, and examples thereof include suspension polymerization, emulsion polymerization, solution polymerization, and bulk polymerization. The vinyl copolymer,
It has two or more maxima in the molecular weight distribution. The low-molecular-weight and high-molecular-weight products of the vinyl copolymer may be hot-melt-blended, but in order to disperse both components more uniformly, it is preferable to remove the solvent after dispersing in a solvent. It is more preferable to polymerize the low molecular weight substance in the presence of the high molecular weight substance.

In the present invention, the amorphous saturated polyester is obtained by polycondensation of a polyhydric alcohol with a polybasic acid or its anhydride or a lower alkyl ester,
It has no melting point.

The polyhydric alcohol is not particularly restricted but includes, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 2,2- Examples thereof include dimethylpropane-1,3-diol, bisphenol A, an alkylene oxide adduct of bisphenol A, polyethylene glycol, glycerin, trimethylolpropane, and pentaerythritol.

The above polybasic acid is not particularly limited. Examples thereof include phthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octylsuccinic acid, benzenetricarboxylic acid, naphthalenetricarboxylic acid, and cyclohexane. Examples include tricarboxylic acids, anhydrides of these acids, lower alkyl esters, and the like.

In the present invention, the amorphous saturated polyester has a glass transition point of 45 to 70 ° C. When the temperature is lower than 45 ° C., the storage stability of the obtained toner decreases. When the temperature exceeds 70 ° C., the softening point becomes high, and the effect of improving the fixing property of the obtained toner is not recognized, and in some cases, the fixing property is lowered.

In the present invention, the glass transition point is determined according to JIS
It is measured according to K 7121 and is measured in accordance with JIS K 7121.
The glass transition point is defined as the midpoint glass transition temperature Tmg described in 9.3 “How to determine glass transition temperature”.

In the present invention, the amorphous saturated polyester has a flow softening point of 85 to 105 ° C. When the temperature is lower than 85 ° C., the storage stability of the obtained toner decreases. 105
When the temperature exceeds ℃, the effect of improving the fixing property of the obtained toner is not recognized, or the fixing property is reduced in some cases.

In the present invention, the flow softening point is measured according to the flow softening point measurement conditions shown in Table 1, and the temperature at the point T of the flow curve corresponding to h / 2 in the analysis flowchart shown in FIG. Defined as the flow softening point.

[0026]

[Table 1]

In the present invention, the amorphous saturated polyester has a durometer hardness of 90 or more in A hardness. 90
If it is less than 1, the resin strength becomes weak, and fine powder is generated in the developing machine, so that fogging is likely to occur.

The durometer hardness (A hardness) in the present invention is measured according to JIS K7215. The measurement sample used was a sample obtained by melting and cooling an amorphous saturated polyester into a plate shape and solidifying it.
The measurement was performed using a type A durometer (manufactured by Kamishima Seisakusho Co., Ltd.) conforming to 7215, and the average value measured five times with the same sample was taken as the measurement result.

The resin composition for a toner according to the present invention comprises the above-mentioned amorphous saturated polyester and the above-mentioned vinyl copolymer. The method of the compounding is not particularly limited, for example, a method of hot-melt blending the amorphous saturated polyester and the vinyl copolymer, dispersing the amorphous saturated polyester in a solvent together with the vinyl copolymer. After that, the solvent is removed, and the like.However, in order to more uniformly disperse the amorphous saturated polyester in the vinyl copolymer, the amorphous saturated polyester and the vinyl copolymer It is preferable to polymerize the low molecular weight polymer component of the vinyl copolymer in the presence of a high molecular weight polymer component.

The mixing ratio of the amorphous saturated polyester and the vinyl copolymer is 1/80 to 10/1 by weight.
Is preferably, and more preferably 1/50 to 4/1.
If it is less than 1/80, the effect of improving the fixing property is hardly exhibited, and
If it exceeds 0/1, the dispersibility may decrease.

Further, as long as the object of the present invention is not impaired, vinyl acetate and vinyl acetate are contained in the resin composition for toner of the present invention.
A polymer such as vinyl chloride may be mixed, and vinyl acetate, vinyl chloride, or the like may be copolymerized with the vinyl copolymer. In the resin composition for a toner of the present invention, among the epoxy resin, the urethane resin and the vinyl resin,
Those having a weight average molecular weight of 30,000 to 300,000 in PC may be mixed, and aliphatic amide, bisaliphatic amide, metal soap, paraffin and the like may be mixed.

The toner of the present invention 2 comprises the toner resin composition of the present invention 1. The toner of the present invention 2 is obtained by adding a colorant, a charge control agent, and the like to the resin composition for a toner, and further, if necessary, dispersing and mixing magnetic powder and the like.
It is manufactured by hot melting, kneading and pulverizing.

The colorant is not particularly restricted but includes, for example, carbon black, aniline black, phthalocyanine blue, quinoline yellow, lamp black, rhodamine-B, quinacridone and the like. The amount of the colorant to be added is usually 1 to the resin composition for a toner.
00 parts by weight, 1 to 10 parts by weight.

The charge control agents include those for positive charge and those for negative charge. Examples of the positive charge control agent include a nigrosine dye, an ammonium salt, a pyridinium salt, and azine. Examples of the negative charge control agent include a chromium complex and an iron complex.
The amount of the charge control agent is usually 0.1 to 10 parts by weight based on 100 parts by weight of the resin composition for a toner.

To the toner of the present invention 2, a polyethylene wax, a polypropylene wax or the like may be added as a releasing agent, and hydrophobic silica or the like may be added to enhance fluidity. Further, a magnetic powder may be mixed with the toner of the present invention 2 to be used as a magnetic toner.

The resin composition for a toner and the toner of the present invention have excellent fixability, anti-offset property, storability and transparency and have no problem of fog by having the above-mentioned constitution.

[0037]

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.

Embodiment 1Production of resin composition  75 parts by weight of styrene, 25 parts by weight of n-butyl acrylate
Having a maximum molecular weight of 1,000,000 obtained by polymerizing
Polymer A was 40 parts by weight, and the glass transition point was 57.7.
° C, flow softening point 89.5 ° C, durometer hardness
10 parts by weight of an amorphous saturated polyester having an A hardness of 96
100 parts by weight of toluene are charged into a flask and dissolved.
Was. After purging the flask with nitrogen gas, toluene
To the boiling point. Stir with toluene refluxing.
While stirring, 81 parts by weight of styrene, n-butyl acrylate
14 parts by weight, methyl methacrylate 5 parts by weight, polymerization started
Benzoyl peroxide (4.5 parts by weight)
The solution was added dropwise over a period of time to perform coexisting solution polymerization. After dropping,
Aging for 1 hour while stirring under reflux of toluene
To polymerize a low molecular weight polymer B with a maximum molecular weight of 10,000
did. Then gradually raise the temperature in the flask to 180 ° C.
Solvent while removing the toluene under reduced pressure.
A fat composition I was obtained. The obtained resin composition I for toner
The measured values of the low softening point and the glass transition point are shown in Table 2.

[0039]Manufacture of toner  Using the resin composition for toner I obtained above,
After mixing the above composition and melting and kneading at 150 ° C.,
About 10 μm toner particles obtained by
Hydrophobic silica (R972, manufactured by Nippon Aerosil Co., Ltd.)
Toner I was obtained by adding 3% by weight. Resin composition for toner I 100 parts by weight Chromium-containing dye (Bontron S-34, manufactured by Orient Chemical Industries) 1.5 parts by weight Carbon black (MA-100, manufactured by Mitsubishi Chemical Corporation) 6.5 parts by weight Polypropylene wax ( Viscol 660P manufactured by Sanyo Chemical Industries, Ltd.) 4.0 parts by weight

Example 2 A polymer having a maximum molecular weight of 300,000 was obtained by polymerizing 75 parts by weight of styrene, 20 parts by weight of n-butyl acrylate, and 5 parts by weight of methyl methacrylate. Changed to a polymer, the amorphous saturated polyester was changed to a polyester having a glass transition point of 66.3 ° C., a flow softening point of 102.3 ° C., and a durometer hardness of 92,
When polymerizing the low molecular weight polymer B, the composition of the polymerizable monomer was changed to 78 parts by weight of styrene, 18 parts by weight of n-butyl acrylate, and 4 parts by weight of methyl methacrylate. Change to parts by weight, and the maximum value of the molecular weight is 2
Resin composition for toner II and toner II were obtained in the same manner as in Example 1 except that 10,000 low molecular weight polymers were obtained. Table 2 shows measured values of the flow softening point and the glass transition point of the obtained resin composition II for toner.

Example 3 The high molecular weight polymer A was changed to a high molecular weight polymer having a maximum molecular weight of 1.5 million obtained by polymerizing 70 parts by weight of styrene and 30 parts by weight of n-butyl acrylate. The crystalline saturated polyester is changed to a polyester having a glass transition point of 46.7 ° C., a flow softening point of 87.3 ° C., and a durometer hardness of A hardness of 95, and is polymerizable when polymerizing the low molecular weight polymer B. The composition of the monomer was changed to 80 parts by weight of styrene, 10 parts by weight of n-butyl acrylate, and 10 parts by weight of methyl methacrylate, and the polymerization initiator was changed to 8.5 parts by weight of azobisisobutyronitrile. A toner resin composition III and a toner III were obtained in the same manner as in Example 1, except that a low molecular weight polymer having a maximum molecular weight of 5000 was obtained. Table 2 shows the measured values of the flow softening point and the glass transition point of the obtained resin composition III for toner.

Comparative Example 1 Amorphous saturated polyester having a glass transition point of 24.6 ° C.
A toner resin composition IV and toner IV were obtained in the same manner as in Example 1 except that the polyester was changed to a polyester having a flow softening point of 70.9 ° C. and a durometer hardness of A hardness of 85.
Table 2 shows the measured values of the flow softening point and the glass transition point of the obtained resin composition IV for toner.

Comparative Example 2 Amorphous saturated polyester having a glass transition point of 71.4 ° C.
Flow softening point is 108.6 ° C, durometer hardness is A
Example 2 except that the polyester was changed to a hardness of 98.
In the same manner as in the above, a toner resin composition V and a toner V were obtained. Table 2 shows the measured values of the flow softening point and the glass transition point of the obtained resin composition V for toner.

Comparative Example 3 Benzoyl peroxide used for polymerizing the low molecular weight polymer B was
Resin composition VI for toner and toner VI were obtained in the same manner as in Example 1 except that a low molecular weight polymer having a maximum molecular weight of 40,000 was obtained by changing to 1.3 parts by weight. Table 2 shows the measured values of the flow softening point and the glass transition point of the obtained resin composition VI for toner.
It was shown to.

Comparative Example 4 The high molecular weight polymer A was changed to a high molecular weight polymer having a maximum molecular weight of 100,000 obtained by polymerizing 75 parts by weight of styrene and 25 parts by weight of n-butyl acrylate. Resin for toner was prepared in the same manner as in Example 1 except that benzoyl peroxide was changed to 1.3 parts by weight when polymerizing molecular weight polymer B to obtain a low molecular weight polymer having a maximum molecular weight of 40,000. A composition VII and a toner VII were obtained. Table 2 shows the measured values of the flow softening point and the glass transition point of the obtained resin composition VII for toner.

Comparative Example 5 A toner resin composition VIII and a toner VIII were obtained in the same manner as in Example 1 except that no amorphous saturated polyester was used. Flow softening point of the obtained resin composition for toner VIII,
The measured values of the glass transition point are shown in Table 2.

[0047]

[Table 2]

[0048]test  (1) Fixability Toners I to VI obtained in Examples 1 to 3 and Comparative Examples 1 to 5
II (6.5 parts by weight) with an iron powder cap having a particle size of about 50 to 80 μm.
Mixed with the rear (93.5 parts by weight) to make a developer,
A plurality of unfixed images were produced using the developer. Next, heat fixing
Set the roller surface temperature to 150 ° C and 170 ° C,
Fixes the toner image on the transfer paper on which the unfixed image is formed.
Was. The electrophotographic copying machine used was a commercially available Konica 70
50 was modified. For the formed fixed image
And rub it with a cotton pad.
The degree was calculated and used as an index of fixability. Image density is Macbeth
A reflection densitometer RD-914 manufactured by KK was used. Fixing strength (%) = (image density of fixed image after rubbing / rubbing
(Image density of previous fixed image) × 100

(2) Offset Resistance The toner image of the transfer paper having the unfixed image was fixed at each surface temperature by gradually changing the surface temperature of the heat fixing roller to obtain a copy. At this time, observation was made as to whether or not toner stains occurred in the blank portion, and a temperature region in which no stains occurred was defined as a non-offset temperature region. The difference between the maximum value and the minimum value in the non-offset temperature region was defined as the non-offset temperature width. In Table 3, ↑ indicates that the temperature was higher than the measurable temperature.

(3) Storage Property 20 g of each of the toners I to VIII was filled in a 200 mL sample bottle and left in a thermostat at 50 ° C. for 48 hours.
Using a powder tester PT-E manufactured by Hosokawa Micron Co., Ltd., sieving under conditions of 1 mm in amplitude and 10 seconds, and opening 25
If the remaining amount of the 0 μm sieve was 1 g or less, it was judged as acceptable. ○: passed ×: failed

(4) Confirmation of Image Quality (Presence or Absence of Fog) An unfixed image was formed in the same manner as in the fixing test, the 100th image was fixed, and the image quality (presence or absence of fog) was visually confirmed. ：: Level without problems X: With problems Table 3 shows the test results of the above items.

[0052]

[Table 3]

From Table 3, it was found that the toners of Examples 1 to 3 were excellent in fixing property, anti-offset property and storage stability, and were at a level at which no fogging occurred. In contrast, Comparative Example 1
Any of the toners of Nos. 1 to 5 was inferior in performance.

[0054]

According to the present invention, since it has the above-mentioned constitution, it is excellent in fixing property, offset resistance, storage stability and transparency.
The present invention can provide a toner resin composition and a toner having a level free from fogging.

[Brief description of the drawings]

FIG. 1 is a diagram showing a flowchart for analyzing a flow softening point.

Claims (2)

[Claims] 1. A resin composition for a toner comprising a vinyl copolymer and an amorphous saturated polyester, wherein the vinyl copolymer has at least a molecular weight distribution measured by gel permeation chromatography. It has a maximum value of 3 × 10 ^{3 to} 3 × 10 ⁴ and 2 × 10 ⁵ to 2 × 10 ^6, and the amorphous saturated polyester has a glass transition point of 45 to 70 ° C. and a flow softening point of 85 to 85 ° C. 1
05 ° C and durometer hardness is A hardness 90
A resin composition for toner characterized by the above. 2. A toner comprising the resin composition for a toner according to claim 1.