JP2769864B2 - Method for producing binder resin for toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to the production of a binder resin for a toner used in a dry developer used in electrophotography, electrostatic recording, magnetic recording and the like. About the method.

[Prior Art] Conventionally, many methods have been known as electrophotography, such as U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748, Using a conductive material, an electric latent image was formed on the photoreceptor by various means, and then the latent image was developed using toner, and a toner image was transferred to a transfer material such as paper as necessary. Thereafter, fixing is performed by heating, pressure, heating and pressurizing, or solvent vapor to obtain a copy. When a step of transferring a toner image is provided, a step for removing the residual toner is usually provided.

Development methods for visualizing an electric latent image using toner include, for example, a magnetic brush method described in U.S. Pat.No. 2,874,063, a cascade developing method described in U.S. Pat.No. 2,618,552, and a method described in U.S. Pat. And the method using a conductive magnetic toner described in U.S. Pat. No. 3,909,258.

Conventionally, fine powders in which dyes and pigments are dispersed in natural or synthetic resins have been used as toners applied to these developing methods. For example, particles obtained by finely pulverizing a dispersion of a colorant in a binder resin such as polystyrene to about 1 to 30 μm are used as toner. As the magnetic toner, toner containing magnetic particles such as magnetite is used. On the other hand, in the case of a system using a so-called two-component developer, a toner is usually used by being mixed with carrier particles such as glass beads and iron powder.

Today, such recording methods are widely used not only for general copying machines but also for computer outputs and microfilm printing. As a result, the required performance becomes higher, and various performances such as smaller size, lighter weight, lower energy, higher speed, more maintenance-free, and more personality are required at the same time. Was. In order to satisfy these requirements, the demands on toners have become more severe in various aspects. For example, when the size is reduced, a heat source such as a fixing device or an exposure lamp is pushed into a narrow place, so that the temperature inside the device tends to increase. Therefore, the blocking property of the toner must be further improved. In order to reduce the weight, the fixing roller is designed to be thinner and thinner, and the cleaning mechanism of the fixing roller and the cleaning mechanism of the photoconductor are going to be simple and light.
It is a direction in which a coating device such as an oil for preventing offset is not attached to the fixing device. Therefore, it is necessary to improve the fixing property of the toner, the offset resistance, and the cleaning resistance of the photoconductor. In addition, in order to achieve higher speed than lower energy, the fixability of the toner must be improved, and for more personalization, it is necessary to improve the reliability. It becomes important. Jams often occur when the copy paper is wound around the rollers of the fixing machine, and it is necessary to improve the winding property of the toner on the fixing roller. However, as shown in FIG. 6, the characteristics required for the production of the toner and various characteristics of the toner itself are often contradictory.

In the above example, the demands for the toner are severe, but if these are not improved at the same time, the demands cannot be satisfied. However, there is no point in reducing the developing characteristics such as image quality and toner durability and the toner production efficiency in order to realize these.

These are largely due to the performance of the binder resin of the toner. There have been proposals to improve these with mold release agents, plasticizers and other additives, but these are supplementary.

Various methods have been proposed for improving the binder resin.

For example, JP-A-56-158340 proposes a toner comprising a low molecular weight polymer and a high molecular weight polymer, but since this binder resin is actually difficult to contain a crosslinking component, In order to improve the offset resistance with higher performance, it is necessary to increase the molecular weight of the high molecular weight polymer or increase the ratio. This direction is a direction in which pulverizability is remarkably reduced, and it is difficult to obtain a practically satisfactory one. Further, with respect to a toner blended with a low molecular weight polymer and a crosslinked polymer, Japanese Patent Application Laid-Open No. 58-86558 proposes a toner containing a low molecular weight polymer and an insoluble infusible high molecular weight polymer as main resin components. ing. According to that method, it is thought that the fixability and the pulverizability are improved,
Weight average molecular weight / number average molecular weight of low molecular weight polymer (Mw / M
n) is as small as 3.5 or less, and the insoluble and infusible high molecular weight polymer is as large as 40 to 90 wt%, so it is difficult to satisfy high performance with offset resistance and pulverizability. It is extremely difficult to produce a toner that sufficiently satisfies the fixing property, the anti-offset property, and the pulverization property unless the fixing device has a preventive liquid supply device. Furthermore, if the insoluble infusible high molecular weight polymer increases, the melt viscosity becomes extremely high by heat kneading at the time of toner preparation, so heat kneading at a much higher temperature than usual or heat kneading with a high share As a result, as a result, the former has a problem that the toner characteristics are deteriorated due to the thermal decomposition of other additives, and the latter has a problem that excessive cutting of the molecules of the binder resin occurs and the initial anti-offset performance is hardly obtained.

Further, JP-A-60-166958 discloses a number average molecular weight of 500.
There has been proposed a toner comprising a resin composition obtained by polymerization in the presence of a low molecular weight poly-α-methylstyrene of 1,1,500.

In particular, the publication discloses that the number average molecular weight (Mn) is 9,000 to 30,000.
Although a range of 0 is preferable, if Mn is increased to further improve the offset resistance, the fixing property and the pulverizability at the time of toner production become practically problematic. It is difficult to satisfy sex. As described above, the toner having poor pulverizability at the time of the production of the toner is not preferable because the production efficiency at the time of the production of the toner is lowered, and the toner characteristic is such that a rough toner is apt to be mixed.

In addition, JP-A-56-16144 discloses that the molecular weight distribution by GPC is such that the molecular weight is 10 ³ to 8 × 10 ⁴ and the molecular weight is 10 ⁵ to 2 × 1.
Toner containing a binder resin component having at least one maximum value has been proposed in each of the regions of 0 ^6. In this case, pulverizability, offset resistance, fixing property, filming and fusing to a photoreceptor, image properties, and the like are excellent, but further improvement in offset resistance and fixing property of the toner is demanded.

First, the applicant of the present application disclosed in the application specification of Japanese Patent Application No. 62-57358 (published as Japanese Patent Application Laid-Open No. 63-223014), in particular, by further improving the fixing property and keeping other various performances or We have proposed a binder resin for toner that can meet today's strict requirements while improving it. This means that the THF soluble content is 10-70% by weight, and the molecular weight distribution of GPC
It has at least one peak in the region of 2,000 to 10,000, and has at least one peak or shoulder in the region of molecular weight 15,000 to 100,000, and the content of the component having a molecular weight of 10,000 or less is 10 to 50% by weight based on the resin. It is something that is.

However, in order to further meet various demands, it is strongly required to improve development characteristics, particularly environmental stability and durability stability.

[Problems to be Solved by the Invention] An object of the present invention is to provide a method for producing a binder resin for toner which simultaneously satisfies excellent performance in various items.

Another object of the present invention is to provide a method for producing a binder resin for toner having particularly excellent environmental stability.

Another object of the present invention is to provide a method for producing a binder resin for toner having excellent fixability, and at the same time, excellent offset properties, winding properties and blocking properties.

Another object of the present invention is to provide a method for producing a binder resin for toner having good pulverizability and good toner production efficiency.

Another object of the present invention is to provide a method for producing a binder resin for a toner having excellent fusion resistance such as photo-sensitivity or fusion resistance in an apparatus at the time of pulverization.

Another object of the present invention is to provide a method for producing a binder resin for toner, which has no problem in developability, particularly in image quality, durability and the like.

[Means and Actions for Solving the Problems] The present invention relates to a method for producing a binder resin for a toner, wherein the molecular weight distribution of GPC has a peak in the molecular weight region of 2,000 to 10,000, and the weight average molecular weight / number average molecular weight. Polymerizing a low molecular weight polymer having (Mw / Mn) ≦ 3.5 and Tg ≧ 50 ° C. in a substantially absence of a radical polymerization initiator with respect to the polymerizable monomer; dissolving the polymer in the polymerizable monomer Then, suspension polymerization for producing a high molecular weight polymer was performed, and the THF-insoluble content was 10 to 7
0 wt%, the molecular weight distribution of the THF-soluble matter by GPC is Mw / Mn ≧ 5, has at least one peak in a molecular weight range of 2,000 to 10,000, and has a molecular weight of 15,000 to 100,000.
It has at least one peak or shoulder in the region of 0, and has a molecular weight of 1
Less than 0,000 component is 10-50% by weight based on the whole resin
And a step of preparing a contained resin composition.

In particular, as a result of intensive studies to further improve environmental stability, it has been found that a molecule at the end of a low molecular weight compound is a problem. That is, since it is a low-molecular-weight substance, the number of terminals is larger than that of a high-molecular-weight substance, and an initiator fragment is bonded thereto. By removing this, the developability, especially the environmental stability, can be further improved.

 The configuration of the present invention will be described.

As a result of intensive studies to achieve the above objectives,
The production of a polymer having a peak in the molecular weight range of 2000 to 10,000 is polymerized by thermal polymerization. Further, an appropriate polymerization temperature is used depending on the required molecular weight. In general, in thermal polymerization, the higher the reaction temperature, the lower the molecular weight is obtained. At the same time, the higher the reaction temperature, the lower the viscosity of the system. Therefore, a uniform temperature distribution can be easily obtained without accumulation of heat of polymerization.

As a result, a polymer that satisfies the required items can be obtained stably and advantageously in terms of cost. As a proposal of such a method, JP-A-56-8416 proposes a method of polymerizing a high-molecular-weight polymer without using an initiator, dissolving this in a monomer, and polymerizing a low-molecular-weight polymer. In addition, there are initiator fragments at many ends of the low molecular weight product, and environmental stability is not preferable.

In the method of the present invention, the preferable polymerization temperature is 150 to 300.
A range of ° C is used.

As the solvent, xylene, toluene, cumene, cellosolve acetate, isopropyl alcohol, benzene or the like is used. In the case of a styrene monomer, xylene, toluene, cumene or the like is preferably used.

Furthermore, the binder resin obtained by such a method has no decomposition products due to a radical initiator. For example, benzoic acid generated when a low molecular weight polymer is polymerized by a conventional method using benzoyl peroxide has a bad influence on development. However, such effects are not exerted in the case of the present invention.

In addition, for example, when a low-molecular weight polymer is polymerized by a conventional method using azobisisobutyronitrile, an initiator fragment is added to a resin terminal, and the chargeability may be changed. There is no such effect.

The term "polymerization in the absence of a radical initiator" means that the polymerization is carried out substantially by thermal polymerization, and a generally known radical initiator may be used in an amount of less than 0.1% by weight based on the polymerizable monomer.

On the other hand, when the binder resin is dissolved with a solvent such as THF,
Insoluble matter and soluble matter can be separated, and the molecular weight distribution of the soluble matter can be measured by GPC. Focusing on the peaks of the molecular weight distribution of the THF-insoluble component and the THF-soluble component, the relationship between the position and the pulverizability is as shown in FIG. From this, a system having no or little THF-insoluble matter is very disadvantageous in pulverizability, and as described above, in order to improve pulverizability, the peak position of the molecular weight distribution of the THF-soluble component is simply changed to a low molecular weight. The direction of shifting to the position of
It supports that it is difficult to satisfy both offset resistance and crushability. From this study, it is very effective to include a specific amount of THF-insoluble components not only for the offset resistance but also for the purpose of improving the pulverizability, as generally considered.

Further, regarding the molecular weight distribution of the THF-soluble component and the property of whether the fixable temperature is high or low (hereinafter, simply referred to as fixability), offset resistance, crushability, and blocking resistance, for example, as shown in FIG. Approximately 10,000 in molecular weight distribution
The function of a molecular weight of less than about 10,000 or more differs. That is, the content ratio of the component having a molecular weight of less than 10,000 relative to the entire binder resin does not strongly influence the fixing property or the anti-offset property, as is generally said, but is almost related to either in a specific range. Instead, it is strongly related to grindability. Furthermore, in the binder resin, the THF-insoluble component basically affects the offset resistance, the winding property, the pulverizability, and
The F-soluble component having a molecular weight of less than 10,000 mainly affects the pulverizability, blocking property, fusing property to the photoreceptor, filming property, and fusing to the inner wall of the pulverizing apparatus.
The soluble component having a molecular weight of 10,000 or more mainly affects the fixability. And the ratio of the components having a molecular weight of less than 10,000 is 10
~ 50 wt% is good, preferably 20-39 wt%. In order to achieve sufficient performance, the molecular weight should be less than 10,000 and 2,000
Above (preferably 2,000 to 8,000), a peak or shoulder is required in the region of molecular weight 15,000 to 100,000 (preferably 20,000 to 70,000), and there is no peak at 2,000 to 10,000 but peak at a molecular weight of less than 2,000. On the other hand, if the proportion of the component having a molecular weight of less than 10,000 exceeds 50% by weight, problems such as blocking resistance, fusing to a photoreceptor, filming, and fusing to the inner wall of a pulverizer become somewhat problematic. Whether there is no peak at a molecular weight of 10,000 or less and a peak exceeding 10,000,
When the ratio of the molecular weight distribution having a molecular weight of less than 10,000 is less than 10 wt%, the pulverizability particularly becomes a problem, and the generation of coarse particles also becomes a problem.

In addition, if there is no peak or shoulder in the region with a molecular weight of 15,000 or more, and only in the region with a molecular weight of less than 15,000, offset resistance, fusion to the photoreceptor, filming,
The adhesion to the inner wall of the pulverizer becomes a problem. Molecular weight 15,000-10
If there is no peak or shoulder in the region of 0,000 and there is a main peak exceeding 100,000, crushability becomes a problem.

Further, the THF-soluble component needs to satisfy Mw / Mn ≧ 5, and when Mw / Mn is less than 5, the offset resistance tends to decrease, which causes a problem. Preferably, Mw / Mn is 80 or less, and more preferably, 10 ≦ Mw / Mn ≦ 60. In particular, when Mw / Mn is 10 ≦ Mw / Mn ≦ 60, particularly excellent performance is exhibited in various characteristics such as pulverizability, fixing property, anti-offset property and image quality.

Further, the THF-insoluble content in the resin must be 10 to 70% by weight (preferably 10 to 60% by weight). If the THF-insoluble content is less than 10 wt%, offset resistance and wrapping properties become problems, and 70 wt%
%, A problem such as degradation of molecular chains due to thermal kneading during toner production occurs. Preferably, 15 to 59 wt%
(More preferably, 15 to 49 wt%).

Further, the glass transition point Tg ₁ of the resin having a molecular weight distribution of 10,000 or less in the molecular weight distribution of the THF soluble component and the glass transition point Tg _t
When comparing, when a relationship of Tg ₁ ≧ Tg _t -5, fixability, grindability, fusion to the photosensitive member, filming, fusing of the pulverizer inner wall, blocking resistance, etc., better I found it to be.

Here, Tg ₁ is measured by the following method. At a temperature of 25 ° C., THF was flowed at a flow rate of 7 ml / min, and a THF sample solution having a concentration of about 3 mg / ml of a THF-soluble component in the resin composition was injected into a molecular weight distribution measuring device of about 3 ml to give a molecular weight of 10,000. The following components are separated. After fractionation, the solvent is distilled off under reduced pressure, and further dried at 90 ° C. under reduced pressure for 24 hours. Perform the above operation until about 20 mg of a component having a molecular weight of 10,000 or less is obtained.
In perform annealing for 48 hours, the Tg was measured by differential scanning calorimetry after this, this value and Tg _1.

TSKgel G2000H, TSKgel G2500
H, TSKgel G3000H, TSKgel G4000H (both from Toyo Soda Kogyo KK) and the like are used.

In the present invention, TSKgel G2000H and TSKgel G3000H were used in combination.

The Tg _t is 50 ° C. The resin is Tg of the resin, and annealed for 48 hours, determined by the subsequent differential scanning calorimetry.

The most preferred embodiment of the present invention, as shown in FIG.
In the GPC molecular weight of the THF-soluble component, the molecular weight is 15,000 to 100,00.
The height of the highest peak in the zero area and h _2, the molecular weight
H ₁ the height of the highest peak in the region of 2,000 to 10,000
Then, it is a resin or a resin composition having a ratio of h ₁ / h ₂ of 0.4 to 4.0 / 1. Further, the number average molecular weight of the THF-soluble component is preferably 2,000 ≦ Mn ≦ 9,000. If Mn <2,000, offset properties and the like become problems, and if 9,000 <Mn, pulverizability and fixing properties become problems.

The THF-insoluble component in the present invention indicates a weight ratio of a polymer component (substantially crosslinked polymer) insoluble in THF in the resin composition, and indicates a degree of crosslinking of the resin composition containing the crosslinking component. It can be used as a parameter to indicate. The THF-insoluble matter is defined by a value measured as follows.

Specifically, 0.5 to 1.0 g of a resin sample (24 mesh pass, 60 mesh on powder) is weighed (w ₁ g), placed in a cylindrical filter paper (for example, No.86R made by Toyo Filter Paper), passed through a Soxhlet extractor, and subjected to solvent extraction. For 6 hours using THF in an amount of 100 to 200 ml, evaporating the soluble components extracted by the solvent, and then vacuum-drying at 100 ° C. for several hours to weigh the amount of the THF-soluble resin components (w ₂ g). The THF-insoluble content of the resin is obtained from the following equation.

In the present invention, the molecular weight of a peak or / and a shoulder of a chromatogram by GPC (gel permeation chromatography) is measured under the following conditions.

That is, the column was stabilized in a heat chamber at 40 ° C, and THF was added to the column at this temperature as a solvent.
(Tetrahydrofuran) is flowed at a flow rate of 1 ml per minute, and a 50-200 μl THF solution of a resin adjusted to a sample concentration of 0.05 to 0.6% by weight is injected for measurement. In the measurement of the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number. Standard polystyrene samples for preparing calibration curves include, for example, Pressure Chemi
cal Co. or Toyo Soda Kogyo Co., Ltd.
× 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ ,
It is suitable to use 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ and at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

As a column, in order to accurately measure a molecular weight region of 10 ³ to 2 × 10 ⁶ , it is preferable to combine a plurality of commercially available polystyrene gel columns, for example, μ-styr manufactured by Waters.
agel 500,10 ³ , 10 ⁴ , 10 ⁵ union and Showa Denko Shod
ex KF-80M, KF-801,803,804,805 combination, KA
-802,803,804,805 combination or TSK made by Toyo Soda
gel G1000H, G2000H, G2500H, G3000H, G4000H, G5000H, G600
A combination of 0H, G7000H and GMH is preferred.

The weight% of the binder resin having a molecular weight of 10,000 or less according to the present invention is obtained by cutting out the molecular weight of 10,000 or less in the chromatogram by GPC, calculating the weight ratio with the cutting weight having a molecular weight of 10,000 or more, and using the above-described weight% of the THF-insoluble portion, The weight% based on the binder resin is calculated.

As the constituent components of the resin of the present invention, various resins can be used as long as they are generally used as a resin for a toner and can achieve the above-mentioned molecular weight distribution. Among them, a vinyl monomer is used. Preference was given to vinyl polymers, vinyl copolymers, and compositions of the polymer and the copolymer.

Examples of the vinyl monomer (monomer) applicable to the present invention include styrene such as styrene, α-methylstyrene, and p-chlorostyrene, and their substituted products; acrylic acid,
Such as methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. Monocarboxylic acid having a double bond or a substituted product thereof; dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like; and substituted products thereof; eg, vinyl chloride, vinyl acetate Vinyl esters such as vinyl benzoate; vinyl ketones such as vinyl methyl ketone and vinyl exyl ketone; vinyl esters such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether Vinyl monomers vinyl ether and the like can be used singly or two or more. Among them, a combination of a styrene polymer and a styrene copolymer is preferable.

As the crosslinkable monomer, a compound having two or more polymerizable double bonds is mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate; divinylaniline And divinyl compounds such as divinyl ether, divinyl sulfide and divinyl sulfone, and compounds having three or more vinyl groups are used alone or as a mixture. Among them, divinylbenzene is effective.

Further, the resin of the present invention shows a considerably different glass transition point depending on the kind and composition of the monomer contained as a component, but the glass transition point in the range of 40 to 80 ° C is effective. More preferably, the glass transition point is preferably from 50 to 65 ° C. in terms of blocking resistance and fixing property. When the glass transition temperature is lower than 40 ° C., thermal aggregation caking during storage of the toner is very likely to occur, and aggregation problems in a copying machine are more likely to occur. Conversely, glass transition point is 80 ℃
In the case where the ratio exceeds 1, the heat fixing efficiency also deteriorates.

In the method for producing a binder resin according to the present invention, the first resin is produced by polymerization, the first resin is dissolved in a polymerizable monomer, and the polymerizable monomer is dissolved in the presence of the resin and a crosslinking agent. Is subjected to suspension polymerization. The first resin is preferably dissolved in 10 to 120 parts by weight, preferably 20 to 100 parts by weight, based on 100 parts by weight of the monomer for suspension polymerization. About 0.
It is preferable to use 1 to 2.0 wt%. These conditions may be slightly varied depending on the type of the initiator and the reaction temperature.

A case where the first polymer is dissolved in a monomer and suspension polymerization is performed to obtain the binder resin; a case where the first polymer is suspended and polymerized without dissolving the first polymer; and a case where the first polymer is dissolved. Has been found to be different from a blend polymer in which is simply mixed.

The former is that the high molecular weight component is slightly larger than the latter in the GPC chromatogram of the THF-soluble component. The former has a molecular weight of 300,000 or more, which is 3 to 25% by weight of the whole resin, and is clearly higher than the latter. This is considered to be due to the fact that the dissolved first polymer affects the suspension polymerization, and this has an effect more than the merit of uniformly mixing the polymers. For more details, GP in the attached drawings
This will be described with reference to the C chart.

FIG. 1 of the accompanying drawings shows a GPC chart of a THF-soluble component of the resin composition obtained in Example 1 described later. Second
The figure shows a chart of GPC of polystyrene prepared by solution polymerization which is the first polymerization in Example 1.
The polystyrene was soluble in THF, was soluble in the styrene monomer and n-butyl acrylate monomer, which were the polymerization monomers, and had a main peak at a molecular weight of 3,500. FIG. 3 is a GPC chart of a THF-soluble component of a styrene-n-butyl acrylate copolymer prepared by the second polymerization under the same conditions except that the polystyrene is not added, but produced by suspension polymerization. Is shown. The styrene-n-butyl acrylate copolymer had a main peak at a molecular weight of 40,000.

FIG. 4 is a combination of the chart of FIG. 2 and the chart of FIG.

FIG. 5 shows a combination of the chart of FIG. 1 and the chart of FIG. 4 (solid lines are indicated by broken lines). As is clear from FIG. 5, the resin composition obtained in Example 1 according to the present invention has a GPC chart different from that obtained by simply mixing separately polymerized polystyrene and styrene-n-butyl acrylate copolymer. Had. In particular, it is found that a polymer component that was not generated by the styrene-n-butyl acrylate copolymer alone was formed on the high molecular weight side. This high molecular weight component, during the suspension polymerization of the second stage polymerization, because the polystyrene prepared in the first stage polymerization is present, the polystyrene acts as a polymerization regulator, As a result, it is considered that the synthesis of the THF-insoluble component and the THF-soluble component of the styrene-n-butyl acrylate copolymer was adjusted. The resin composition according to the present invention has a TH
F-insoluble, THF-soluble high molecular weight component, THF-soluble intermediate molecular weight component and THF-soluble low molecular weight component are uniformly mixed. Further, the resin composition according to the present invention has a molecular weight of 30 due to the molecular chain being cut by the melt-kneading step in the production of toner.
It has the ability to generate a new peak in an area of 10,000 or more (preferably 500,000 or more) to adjust the fixing property and offset resistance of the toner.

Furthermore, in the present invention, it is preferable that a component having a molecular weight of 300,000 or more in the THF-soluble GPC of the toner can contain 5 to 30% by weight (preferably 10 to 30% by weight) based on the binder resin. Further, those having a clear peak at a molecular weight of 300,000 or more (preferably 500,000 or more) in the THF-soluble component of the toner are preferred from the viewpoint of improving the offset resistance and the winding resistance.

 The suspension polymerization according to the present invention will be described below.

In the suspension polymerization, the polymerization is preferably carried out with 100 parts by weight or less of the monomer per 100 parts by weight of the aqueous solvent (preferably 10 to 90 parts by weight). As a dispersant that can be used, polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, and the like are used, and there is an appropriate amount in terms of the amount of a monomer relative to an aqueous solvent, but generally 0.05 to 1 part by weight based on 100 parts by weight of an aqueous solvent. Used. Polymerization temperature is 50-95 ° C
Is appropriate, but should be appropriately selected depending on the initiator used and the target polymer. As the type of the initiator, any one can be used as long as it is insoluble or hardly soluble in water.For example, benzoyl peroxide, tert-butyl peroxyhexanoate, etc. are used in 100 parts by weight of the monomer. It is used in an amount of 0.5 to 10 parts by weight.

In the toner using the resin of the present invention, in addition to the above-mentioned binder resin component, the following compound is contained in a proportion smaller than the content of the binder resin component, as long as the effect of the present invention is not adversely affected. You may.

For example, silicone resin, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin such as low molecular weight polyethylene or low molecular weight polypropylene, aromatic type Petroleum resin, chlorinated paraffin, paraffin wax and the like.

When a magnetic toner is prepared using the binder resin of the present invention, magnetic fine particles are contained in the toner. The magnetic fine particles may be any material that exhibits magnetism or is magnetizable,
For example, iron, manganese, nickel, cobalt, chromium and other metals, magnetite, hematite, various ferrites,
There are manganese alloys and other ferromagnetic alloys, and these have an average particle size of about 0.05 to 5μ (more preferably 0.1 to 1μ).
Can be used. The amount of the magnetic fine particles contained in the magnetic toner is 15 to 70% by weight of the total weight of the toner.
Is good.

In addition, various substances can be added to the toner according to the present invention for the purpose of controlling coloring and charge. For example, carbon black, iron black, graphite, nigrosine, metal complexes of monoazo dyes, ultramarine, phthalocyanine blue, hansa yellow, benzidine yellow, quinacridone, various lake pigments, and the like.

The toner prepared from the above-described binder resin, magnetic fine particles, colorant, charge control agent, and the like has strong resistance to the load applied in the developing device, and was not crushed and deteriorated in the durability test.

As a fixing aid, an ethylene-based olefin polymer may be used together with a binder resin.

Here, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polyethylene There is an ionomer having a skeleton. In the above copolymer, 50 mol% or more (more preferably 60 mol%
Above) is preferred.

Next, an electrophotographic method using a developer using the resin according to the present invention will be described.

The step of developing the electric latent image using toner includes the above-described magnetic brush method, cascade development method, powder cloud method, a method using a conductive magnetic toner described in U.S. Pat.No. 3,909,258, There is a method using a high-resistance magnetic toner described in JP-A-53-31136.
The developer using the resin according to the present invention is suitable for a developing method using a so-called one-component developer containing magnetic fine particles. In the step of transferring the developed image to the transfer-receiving member, an electrostatic transfer method such as a corona transfer method or a bias transfer method is used.

Further, in the toner using the binder resin of the present invention,
A blade cleaning method, a fur brush cleaning method, or the like is applied to the step of removing the residual toner on the photosensitive layer or the insulating layer, and is particularly suitable for the blade cleaning method.

The powder image on the member to be transferred needs to be fixed on the member. As a method for this, a heat fixing method, a solvent fixing method, a flash fixing method, a laminating fixing method, and the like can be used. Suitable for roller fixing system.

Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

[Example] Example 1 50 parts by weight of cumene and 100 parts by weight of a styrene monomer were charged into an autoclave equipped with a stirrer, and heated at 280 ° C for 3 hours to complete polymerization, and cumene was removed under reflux. The obtained polystyrene was dissolved in THF, Mw = 3,700, Mw / Mn = 2.5, the molecular weight at which the main peak of GPC was located was 3,500, and Tg = 58 ° C.

30 parts by weight of the above polystyrene was dissolved in the following monomer mixture to prepare a mixed solution.

In the above mixed solution, partially saponified polyvinyl alcohol
170 parts by weight of water in which 0.1 part by weight was dissolved was added to obtain a suspension dispersion. The above dispersion was added to a reactor filled with 15 parts by weight of water and purged with nitrogen, and subjected to a suspension polymerization reaction at a reaction temperature of 70 to 95 ° C. for 6 hours. After completion of the reaction, the mixture was filtered, dehydrated and dried to obtain a composition of polystyrene and styrene-n-butyl acrylate copolymer. In the composition, a THF-insoluble component and a THF-soluble component are uniformly mixed, and polystyrene and styrene-acrylic acid n
-Butyl copolymer was uniformly mixed. The THF insoluble content of the obtained resin composition (using a resin composition powder of 24 mesh pass, 60 mesh on) was 25 wt%. Also, TH
When the molecular weight distribution of the F-soluble component was measured, it had peaks at positions of 44,000 and 34,000, and Mn = 0.55 million, Mw = 130,000, Mw / Mn = 24,
The molecular weight of 10,000 or less was 25 wt%. Furthermore, the Tg of the resin
Was 59 ° C., and the glass transition point Tg ₁ of the component of 10,000 or less fractionated by GPC was 58 ° C.

 The GPC chromatogram of the THF-soluble component is shown in FIG.

The properties relating to the molecular weight of each resin and the resin composition were measured by the following methods.

Using Shodex KF-80M as a column for GPC measurement,
Installed in a 40 ° C heat chamber of a measuring device (Waters 150C ALC / GPC) at a THF flow rate of 1 ml / min.
Under the conditions described above, the sample (concentration of THF
GPC was measured by injecting μl. As a calibration curve for molecular weight measurement, the molecular weight is 0.5 × 10 ³ , 2.35 × 10 ³ , 10.2 × 10 ³ , 35 × 1
0 ³ , 110 × 10 ³ , 200 × 10 ³ , 470 × 10 ³ , 1200 × 10 ³ , 2700 × 10 ³ ,
A THF solution of 10 points of 8420 × 10 ³ monodisperse polystyrene reference substances (manufactured by Waters) was used.

Example 2 Into an autoclave equipped with a stirrer, 50 parts by weight of cumene, 95 parts by weight of a styrene monomer and 5 parts by weight of an α-methylstyrene monomer were charged and heated at 260 ° C. for 3 hours to complete polymerization, and cumene was removed under reflux. The obtained styrene-α-methylstyrene copolymer has a main peak at a molecular weight of 4,400 in a chart of Mw = 4,500, Mw / Mn = 2.7, GPC, and has a Tg
= 64 ° C.

30 parts by weight of the styrene-α-methylstyrene copolymer was dissolved in the following monomer mixture to prepare a mixed solution.

In the above mixed solution, partially saponified polyvinyl alcohol
170 parts by weight of water in which 0.1 part by weight was dissolved was added to obtain a suspension dispersion. 15 parts by weight of water was added, the dispersion was added to a reactor purged with nitrogen, and reacted at a reaction temperature of 70 to 95 ° C. for 6 hours.
After completion of the reaction, the mixture was filtered, dehydrated and dried to obtain a composition of a styrene-α-methylstyrene copolymer and a styrene-2-ethylhexyl acrylate copolymer.

The THF-insoluble content of this composition was 32% by weight. Also THF
When the molecular weight distribution of the soluble component was measured, the molecular weight was 50,000 and 4.2.
Mn = 0.62, Mw = 130,000, Mw / Mn
= 21, molecular weight of 10,000 or less was 20 wt%. Further, the Tg of the resin was 58 ° C., and the glass transition point Tg ₁ of the component of 10,000 or less collected by GPC was 60 ° C.

Example 3 50 parts by weight of cumene and styrene were added to an autoclave equipped with a stirrer.
90 parts by weight and 10 parts by weight of methyl methacrylate monomer were added, and the mixture was heated at 270 ° C. for 3 hours to complete the polymerization, and cumene was removed under reflux. The obtained styrene-methyl methacrylate copolymer had a main peak at the position of Mw = 3,900, Mw / Mn = 2.7, molecular weight 4,100, and had Tg = 61 ° C. 40 parts by weight of the styrene-methyl methacrylate copolymer was dissolved in the following monomer mixture to prepare a mixed solution.

In the above mixed solution, partially saponified polyvinyl alcohol
170 parts by weight of water in which 0.1 part by weight was dissolved was added to obtain a suspension dispersion. 15 parts by weight of water was added, the dispersion was added to a reactor purged with nitrogen, and reacted at a reaction temperature of 70 to 95 ° C. for 6 hours.
After completion of the reaction, the mixture was filtered, dehydrated, and dried to obtain a styrene-methyl methacrylate copolymer and styrene-methacrylic acid n-
A butyl copolymer composition was obtained.

The THF-insoluble content of this composition was 35% by weight. Also THF
When the molecular weight distribution of the soluble component was measured, it had peaks at 44,000 and 43,000, and Mn = 0.59 million, Mw = 92,000, Mw / Mn = 16, and the molecular weight of 10,000 or less was 32 wt%. Furthermore, the Tg of the resin is 60 ° C
The glass transition point Tg ₁ of the component having a molecular weight of 10,000 or less collected by GPC was 58 ° C.

Example 4 Into an autoclave equipped with a stirrer, 50 parts by weight of cumene and 100 parts by weight of a styrene monomer were charged and heated at 280 ° C. for 3 hours to complete polymerization, and cumene was removed under reflux. The obtained polystyrene was dissolved in THF, Mw = 3,700, Mw / Mn = 2.5, the molecular weight at which the main peak of GPC was located was 3,500, and Tg = 58 ° C.

30 parts by weight of the above polystyrene was dissolved in the following monomer mixture to prepare a mixed solution.

In the above mixture, partially saponified polyvinyl alcohol 0.
170 parts by weight of water in which 1 part by weight was dissolved was added to obtain a suspension dispersion. The above dispersion was added to a reactor filled with 15 parts by weight of water and purged with nitrogen, and reacted at a reaction temperature of 70 to 95 ° C. for 6 hours. After completion of the reaction, the mixture was filtered, dehydrated, and dried to obtain polystyrene and styrene.
A composition of n-butyl acrylate copolymer was obtained.

The THF insoluble content of this composition was 44% by weight. Also THF
When the molecular weight distribution of the soluble component was measured, the molecular weight was
Mn = 0.58M, Mw = 100,000, Mw / Mn
= 17, molecular weight of 10,000 or less was 21 wt%. Further, the Tg of the resin was 56 ° C., and the glass transition point Tg ₁ of the component of 10,000 or less separated by GPC was 56 ° C.

Example 5 30 parts by weight of cumene and 100 parts by weight of a styrene monomer were charged into an autoclave equipped with a stirrer, heated at 225 ° C. for 4 hours to complete the polymerization, and the cumene was removed under reflux. The obtained polystyrene had a main peak at the position of Mw = 6,900, Mw / Mn = 2.2, molecular weight 7,100, and had Tg = 76 ° C.

30 parts by weight of the above polystyrene was dissolved in the following monomer mixture to prepare a mixed solution.

In the above mixed solution, partially saponified polyvinyl alcohol
170 parts by weight of water in which 0.1 part by weight was dissolved was added to obtain a suspension dispersion. 15 parts by weight of water was added, the dispersion was added to a reactor purged with nitrogen, and reacted at a reaction temperature of 70 to 95 ° C. for 6 hours.
After completion of the reaction, the mixture was filtered, dehydrated and dried to obtain a composition of a styrene polymer and a styrene-n-butyl acrylate copolymer.

The THF-insoluble content of this composition was 30% by weight. Also THF
When the molecular weight distribution of the soluble component was measured, it had peaks at 0.75 million and 43,000, and Mn = 0.65 million, Mw = 100,000, Mw / Mn = 15, molecular weight 1
Less than 10,000 was 18 wt%. Further, the Tg of the resin was 61 ° C., and the glass transition point Tg ₁ of the component of 10,000 or less fractionated by GPC was 70 ° C.

Comparative Example 1 150 parts by weight of cumene was put into a reactor, and the temperature was raised to 85 to 90 ° C. 100 parts by weight of styrene monomer, benzoyl peroxide 8
Parts by weight of the mixture were added dropwise over 4 hours. 85-90 ° C
And the cumene was removed under reflux. The obtained polystyrene was dissolved in THF, and Mw = 3,600, Mw / Mn = 2.6, GP
The molecular weight at which the main peak of C was located was 3,400, and Tg was 55 ° C.

30 parts by weight of the above polystyrene was dissolved in the following monomer mixture to prepare a mixed solution.

In the above mixed solution, partially saponified polyvinyl alcohol
170 parts by weight of water in which 0.1 part by weight was dissolved was added to obtain a suspension dispersion. The above dispersion was added to a reactor filled with 15 parts by weight of water and purged with nitrogen, and subjected to a suspension polymerization reaction at a reaction temperature of 70 to 95 ° C. for 6 hours. After completion of the reaction, the mixture was filtered, dehydrated and dried to obtain a composition of polystyrene and styrene-n-butyl acrylate copolymer. In the composition, a THF-insoluble component and a THF-soluble component are uniformly mixed, and polystyrene and styrene-acrylic acid n
-Butyl copolymer was uniformly mixed. The THF insoluble content of the obtained resin composition (using a resin composition powder of 24 mesh pass, 60 mesh on) was 25 wt%. Also, TH
When the molecular weight distribution of the F-soluble component was measured, it had peaks at positions of 44,000 and 34,000, and Mn = 0.55 million, Mw = 130,000, Mw / Mn = 24,
The molecular weight of 10,000 or less was 25 wt%. Furthermore, the Tg of the resin
Was 57 ° C., and the glass transition point Tg ₁ of the component of 10,000 or less fractionated by GPC was 56 ° C.

Comparative Example 2 150 parts by weight of cumene was put into a reactor, and the temperature was raised to 75 to 80 ° C. A mixture of 100 parts by weight of styrene monomer and 8 parts by weight of azobisisobutyronitrile was added dropwise over 4 hours. Further, the polymerization was completed at 75 to 80 ° C, and cumene was removed under reflux. The obtained polystyrene was dissolved in THF, and Mw = 3,700, M
w / Mn = 2.5, molecular weight where the main peak of GPC is 3,50
0, Tg = 58 ° C.

30 parts by weight of the above polystyrene was dissolved in the following monomer mixture to prepare a mixed solution.

In the above mixed solution, partially saponified polyvinyl alcohol
170 parts by weight of water in which 0.1 part by weight was dissolved was added to obtain a suspension dispersion. The above dispersion was added to a reactor filled with 15 parts by weight of water and purged with nitrogen, and subjected to a suspension polymerization reaction at a reaction temperature of 70 to 95 ° C. for 6 hours. After completion of the reaction, the mixture was filtered, dehydrated and dried to obtain a composition of polystyrene and styrene-n-butyl acrylate copolymer. In the composition, a THF-insoluble component and a THF-soluble component are uniformly mixed, and polystyrene and styrene-acrylic acid n
-Butyl copolymer was uniformly mixed. The THF insoluble content of the obtained resin composition (using a resin composition powder of 24 mesh pass, 60 mesh on) was 25 wt%. Also,
When the molecular weight distribution of the THF-soluble component was measured, it had peaks at positions of 44,000 and 34,000, and Mn = 0.55 million, Mw = 130,000, and Mw / Mn = 2.
4. The molecular weight of 10,000 or less was 25 wt%. Furthermore, the Tg of the resin
Was 59 ° C., and the glass transition point Tg ₁ of the component of 10,000 or less fractionated by GPC was 58 ° C.

Production Example 1 100 parts by weight of the resin composition of Example 1, 80 parts by weight of a magnetic substance, 4 parts by weight of a low molecular weight polypropylene, and 2 parts by weight of a positive charge control agent were kneaded with heat, and were then pulverized using a pulverizer and a classifier. ,
A toner was manufactured.

The pulverizability of this toner raw material was very good, and the processing amount was 15.3 kg / hr to obtain a volume average diameter of 8 μm in pulverized particle size. There was no fusion in the crusher.

A developer in which 0.6 part by weight of hydrophobic silica was mixed with 100 parts by weight of this toner was put into a Canon copier NP-5540, and image quality and fixability were evaluated.

Although 30,000 sheets were durable under an environment of 32.5 ° C./90%, good images were stably obtained. Further, the fixability was very good, and no filming or fusion to the photoreceptor was observed.

Production Example 2 Production Example 1 except that the resin composition of Example 2 was used.
The same results as in Production Example 1 were obtained.

Production Examples 3 to 5 and Comparative Production Examples 1 and 2 Toners were produced in the same manner as in Production Example 1 except that the resin compositions of Examples 3, 4, and 5 were used (Production Examples 3 to 5).
5). On the other hand, a toner was manufactured in the same manner as in Production Example 1 except that the polystyrene used as a raw material of the resin composition in Example 1 and the resin compositions of Comparative Examples 1 and 2 were used (Comparative Production Example 1). ~ 2). The results are shown in the table.

Evaluation Method The pulverizability of the toner raw material was determined by using a fine pulverizer using a jet stream at an air pressure of 5.5 kg / cm ² and a throughput per unit time. At the same time, the inner wall of the pulverizer was observed, and the presence or absence of fusion was examined.

(A) Crushability: Very good: When crushability of 14 kg / hour or more is exhibited.

Good: Shows pulverizability of 11 to less than 14 kg / hour.

Normal: When showing crushability of 6 to less than 11 kg / hour.

Poor: When crushability of less than 6 kg / hour is shown.

Fixability, image quality, and durability were examined using a Canon copier, NP-5540.

The fixability was evaluated by rubbing the image with Silbon C paper 10 times by reciprocating 10 times and applying a load of about 100 g. The peeling of the image was evaluated based on the reduction rate (%) of the reflection density. The evaluation image was viewed at the 200th sheet when 200 sheets were continuously taken.

(B) Development durability: very good: a good image can be obtained even after 30,000-sheet durability.

Almost good: A good image can be obtained even after 20,000 sheets of durability.

Normal: A good image can be obtained even after 10,000 copies.

Poor: Image defects appear after 5,000 sheets.

(C) Fixing property: very good: reduction rate of reflection density 1% or less Good: reduction rate of reflection density 2 to 5% Normal: reduction rate of reflection density 6 to 10% Bad: reduction rate of reflection density 11% or more [Effects of the Invention] According to the present invention, a binder resin for a toner that simultaneously satisfies excellent performance in various items can be obtained, and in particular, a binder resin for a toner having excellent environmental stability can be obtained.

[Brief description of the drawings]

FIG. 1 shows a GPC chart of a THF-soluble component of the resin composition prepared in Example 1 in the accompanying drawings. FIG. 2 shows a GPC chart of the polystyrene used in Example 1, and FIG.
1 shows a GPC chart of a THF-soluble component obtained by suspension polymerization of an n-butyl acrylate copolymer alone. FIG. 4 is a combination of the charts of FIG. 2 and FIG. 3, and FIG. 5 is a chart for comparing and explaining FIG. 1 and FIG. FIG. 6 is a graph showing the correlation between various properties required for the toner, FIG. 7 is a graph showing the relationship between the content of the THF-insoluble component and the pulverizability, and FIG. , 0
4 is a graph showing the correlation between the content of the following components and toner characteristics.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 9/08 G03G 9/087

Claims (1)

(57) [Claims] In a method for producing a binder resin for a toner, the molecular weight distribution of GPC has a peak in a molecular weight range of 2,000 to 10,000, and a weight average molecular weight / number average molecular weight (Mw / Mn) ≦ 3.5, Tg ≧ Polymerizing a low molecular weight polymer at 50 ° C. to the polymerizable monomer in the substantial absence of a radical polymerization initiator; dissolving the low molecular weight polymer in the polymerizable monomer to form a high molecular weight polymer; The suspension polymerization for the production is performed, the THF-insoluble content is 10 to 70% by weight, and the molecular weight distribution of the THF-soluble component by GPC is Mw / Mn ≧ 5, and the molecular weight is 2,000 to 10,000.
Has at least one peak in the region of 00 and a molecular weight of 15,000
A component having a molecular weight of less than 10,000, having at least one peak or shoulder in the region of
Preparing a resin composition containing 50 to 50% by weight of the resin composition.