JPH03101745A - Binder resin for toner and production thereof - Google Patents

Abstract

PURPOSE:To obtain the binder resin for toners which is good for smell by specifying the content of aldehydes at the time of polymerizing a monomer compsn. CONSTITUTION:The content of the aldehydes in the binder resin for toners which is obtd. by polymerizing a polymerizable monomer contg. at lest <=50wt.% styrene monomer and a polymn. initiator is specified to <=0.01wt.%. The mono mer compsn. is subjected to suspension polymn. in an aq. medium having <=0.25mg/l dissolved oxygen quantity to form the styrene resin having <=0.01wt.% content of aldehyde monomers at the time of producing the binder resin for toners. The suspension polymerized resin which has no problems in smell is provided for toners in this way.

Description

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

[Prior Art] Conventionally, as an electrophotographic method, U.S. Patent No. 2,297,6
Although many methods are known, such as Japanese Patent Publication No. 91, Japanese Patent Publication No. 42-23910, and Japanese Patent Publication No. 43-24748, they generally utilize a photoconductive substance and apply it on a photoreceptor by various means. An electrical latent image is formed, then the latent image is developed using toner, and if necessary, the toner image is transferred to a transfer material such as paper, and then fixed by heat, pressure, heat pressure, solvent vapor, etc. and obtain a copy. Further, when a process for transferring a toner image is included, a process for removing residual toner is usually provided.

Development methods for visualizing electrical latent images using toner include, for example, the magnetic brush method described in U.S. Pat. No. 2,874,063 and the U.S. Pat. No. 2,618,552. Cascade development method and 2,221,7
Powder cloud method described in US Pat. No. 76, U.S. Pat.
, 909, 258, which uses conductive magnetic toner, is known.

As toners applied to these developing methods, fine powders in which dyes and pigments are dispersed in natural or synthetic resins have conventionally been used. For example, particles obtained by dispersing a colorant in a binder resin such as polystyrene and pulverizing the particles to about 1 to 30 μm are used as toner. As the magnetic toner, one 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, the toner is usually 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 the output of computer cameras and for printing microfilm. As a result, the required performance has become more advanced, and various performances such as smaller size, lighter weight, lower energy consumption, less maintenance, and more personalization are now required at the same time. In order to satisfy these requirements, requirements for developers have become more stringent in various respects.

For example, as mentioned above, as the range of applications has expanded and it has come to be used in general offices and homes, it is important to pay attention not only to the safety of toner as a material, but also to the odor generated during fixing. It's becoming necessary.

Regarding this odor issue, it is obviously an important issue considering the standpoints of users and manufacturers as mentioned above.
Generally speaking, it is not technically easy to fix a developer, which contains a synthetic resin as a main component and fixes it on a transfer material such as paper by utilizing the softening and melting of the synthetic resin upon heating. Further, in order to solve this problem, there is no point in reducing development characteristics such as image quality or toner durability.

Various methods have been considered to simultaneously satisfy these performances. However, the method of adding additives complicates the system and often causes unpredictable problems. Therefore, it is desirable to improve the odor of the binder resin itself. To this end, it is thought that it is best to reduce the residual amount of odor-causing solvents and polymerizable monomers in the binder resin, and various methods have been developed to date to reduce the amount of residual odor-causing solvents and polymerizable monomers. is proposed.

For example, in Japanese Patent Application Laid-Open No. 55-155632, offset is achieved by using a polymer in which the content of the solvent or polymerizable monomer used to obtain the polymer is less than 0.1% by weight as a binder resin for toner. occurrence, storage stability,
It has been proposed to improve fluidity etc.

In JP-A-53-17737, there is a description that residual polymerizable monomers affect the triboelectric charging properties, blocking properties, and fixing properties of toners, and in order to obtain a polymerized product as a binder resin for toners. It has been proposed to reduce the amount of residual solvent or polymerizable monomer used.

In JP-A No. 64-70765, a toner with a residual monomer content of 200 ppm or less was proposed in order to solve problems such as emitting an odor during melting and cross-fertilization, which worsens the workplace environment, or emitting an odor during copying, which causes discomfort. Proposals have been made for resins for Residual monomer amount is 200ppm
It is stated that if this value is exceeded, blocking resistance and vinyl chloride plasticizer resistance will decrease, and odor problems will remain.

However, when specifically targeting the problem of odor,
Considering the future expansion of the application range of electrophotography, electrostatic recording, etc., it cannot be said that simply reducing the amount of remaining polymerizable monomer is sufficient.

Generally, as methods for polymerizing binder resins for developers, solution polymerization methods, bulk polymerization methods, suspension polymerization methods, etc. are known. As proposed in No. 62-57358, it is easy to manufacture because there is no need to remove the solvent or a strong stirring device, and TI{F insoluble, which has a large effect on toner fixing and offset performance. This method is suitable as a method for polymerizing a binder resin for toner, as it can contain an arbitrary amount of the above-mentioned components.

However, in the suspension polymerization method, the resin is obtained in the form of beads, so there is no step of removing the solvent or polymerizable monomer while the resin is in a molten state, as in solution polymerization, and the method is used only for the purpose of removing water. Only a drying process is performed. As a result, residual amounts of the solvent and polymerizable monomer tend to increase, and special attention must be paid to the odor problem mentioned above.

[Problems to be Solved by the Invention] An object of the present invention is to provide a binder resin for toner that is good against odor.

In particular, an object of the present invention is to provide a toner binder resin that is polymerized in an aqueous medium and has a good odor.

Another object of the present invention is to provide a binder resin for toner that simultaneously satisfies excellent performance in various aspects.

[Means and effects for solving the problem] The object of the present invention is to provide a bond for toner obtained by polymerizing a monomer composition containing a polymerizable monomer containing at least 50% by weight of a styrene monomer and a polymerization initiator. In the adhesive resin, the content of aldehydes is 0. This can be achieved by using a binder resin for toner, which is characterized in that it has a content of % by weight or less.

Furthermore, in a method for producing a binder resin for a toner by polymerizing a monomer composition containing a polymerizable monomer containing at least 50% by weight of a styrene monomer and a polymerization initiator, the amount of dissolved oxygen is 0.25 mg/R. Production of a binder resin for toner, characterized in that a monomer composition is suspension polymerized in the following aqueous medium to produce a styrenic resin containing 0.01% by weight or less of aldehyde monomers. This is accomplished by a method.

As a result of intensive study on the factors of toner binder resin that affect the odor of toner, the present inventors found that the amount of solvent and polymerizable monomer remaining in the toner binder resin was found to be Of course, it is effective, but more than that, the residual amount of these oxidation products, especially aldehydes generated by air oxidation of polymerizable monomers, has a large effect, and the We were convinced that reducing the residual amount of aldehydes is the best way to prevent toner odor.

In particular, in styrene polymers or copolymers, which are most commonly used as binder resins for toners, benzaldehyde, which is produced by air oxidation of styrene monomers, is the component that causes the most odor problem, so we need to reduce its residual amount. need to be very careful.

According to studies by the present inventors, the content of such aldehydes in the binder resin for toner needs to be 0.01% by weight or less, and particularly preferably 0.01% by weight or less. 005% by weight
The following is good. When the content of aldehydes exceeds 0.01% by weight, the odor of the toner often becomes noticeable.

In view of this problem, the inventors of the present invention have made extensive studies to reduce the amount of aldehydes, and have found that the objective can be achieved by adopting the method described below.

That is, dissolved oxygen in the water used during suspension polymerization was measured at a temperature of 40 to 45°C. 5mg/1 or less, preferably 2. By setting it to 0 mg/β or less, air oxidation of the polymerizable monomer is suppressed, and as a result, the production of aldehydes is suppressed.

In other words, it has been known in the past that in suspension polymerization methods, the atmosphere in the polymerization system is replaced with nitrogen for the purpose of reducing wasteful consumption of polymerization initiators, but the purpose of this is to reduce the polymerization yield. This is not sufficient to aim at reducing aldehydes. It has been found that in order to achieve a reduction in aldehydes, it is necessary to reduce the dissolved oxygen in the water used during suspension polymerization to a certain level or less. Its mechanism of action is thought to be as follows. In other words, in suspension polymerization, a polymerization reaction occurs within droplets of polymerizable monomers suspended in water, and in this polymerization reaction, the droplets of polymerizable monomers come into direct contact with water, and the droplets in the aqueous phase It is thought that it is strongly affected by dissolved oxygen.

As a specific method for reducing dissolved oxygen, various known techniques can be used, but it is preferable to install a nitrogen introduction pipe into the water and flow nitrogen into the water to efficiently remove dissolved oxygen. A method to reduce it is better.

As a result, when the concentration of dissolved oxygen is 2.5 mg # or less in the temperature range of 40 to 45°C, aldehydes are 0.01 wt% or less in the binder resin for toner, and preferably the concentration of dissolved oxygen is 0.01 wt% or less. At 2.0 mg/il' or less, aldehydes are 0.005 wt% or less. At the same time, wasteful consumption of the polymerization initiator by oxygen is reduced, and the residual concentration of the polymerizable monomer can be reduced at the same time.

Further, the suspension of the polymer thus obtained was heated to about 70°C.
It is also possible to carry out a method of heating at the above temperature and simultaneously distilling off the remaining monomers at the same time as water distillation.

The concentration of dissolved oxygen in water is measured by the following method. Using a Nikikaki YSI DO meter, place the electrode in air or water containing a known amount of oxygen, and turn the 02 calibration adjustment knob to adjust the displayed value to the oxygen concentration of the sample.

Next, water having a temperature of 40 to 45° C. is circulated at a flow rate of about 30 cm/sec, and an electrode is inserted therein for measurement. If the electrode is left still, move the electrode by hand and measure.

Read when the displayed value becomes stable.

The amount of aldehydes in the binder resin for toner is determined by the following method using a gas chromatograph.

2. 55 mg DMF as internal standard, 100 mj'
Add acetone to make a solvent containing an internal standard. Next, 200 mg of the toner binder resin is dissolved in 10 ml of the above solvent. After applying it to an ultrasonic shaker for 30 minutes, leave it for 1 hour. Next, it is filtered through a 0.5 pm filter.

The amount of sample to be implanted is 4 parts.

The conditions for gas chromatography are: - Cavillary column (30m x 0.249mm,
DBWAX, film thickness 0.25 μm) ・Detector FID, nitrogen pressure 0. 45kg/cm2, injection concentration 200℃, detector temperature 200
℃, and the column temperature was increased from 50℃ to 30℃ at a rate of 5℃/min.
Increase temperature for 1 minute.

・Preparation of a calibration curve A standard sample prepared by adding the target aldehyde to the sample solution and the same amount of DMF and acetone was measured by gas chromatography in the same way, and the aldehyde and internal standard DM were measured using a gas chromatograph.
Find the weight ratio/area ratio of F.

As mentioned above, in the suspension polymerization method, dissolved oxygen in the aqueous phase is reduced to 2.5
mg/j) or less, the binder resin for toner which is the object of the present invention can be obtained, but it has problems with crushability, anti-offset property, fixing property, filming property on photoreceptor, fusion, and image quality. In order to satisfy the properties to a high degree, as proposed by the present applicant in Japanese Patent Application No. 62-57358, the insoluble content of tetrahydrofuran (diHF) should be 10 to 70% by weight (preferably 10% by weight).
In the molecular weight distribution by GPC of the HF-soluble fraction, MW/Mn≧5, and 20
At least one peak in the region of 00 to 10,000
has at least one peak or shoulder in the molecular weight region of 15,000 to 100,000, and has a molecular weight of 10
,000 or less is preferably 10 to 50% by weight based on the resin.

In the present invention, the TI{F insoluble content refers to THF in the resin composition.
It can be used as a parameter to indicate the degree of crosslinking of a resin composition containing a crosslinked component. The THF-insoluble content is defined by the value measured as follows.

That is, weigh 0.5 to 1.0 g of a resin sample (24 mesh pass, 60 mesh on powder) (Lg).
, put it in a thimble filter paper (for example, No. 86R manufactured by Toyo Roshi Co., Ltd.), apply it to a Soxhlet extractor, and use THF 1 as a solvent.
After extracting for 6 hours using 00-200 mi+ and evaporating the soluble fraction extracted with the solvent, ioo
'c for several hours under vacuum, and the amount of THF-soluble resin component is weighed (wag). The THF-insoluble content of the resin is determined from the following formula.

In the present invention, the molecular weight of the peak and/or shoulder of a chromatogram by GP (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) 1+nj per minute! Measurement is performed by injecting 50 to 200 capes of a THF sample solution of the resin adjusted to a sample concentration of 0.05 to 0.6% by weight. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithm value and the count number of a calibration curve prepared using several types of monodisperse polystyrene standard samples. As a standard polystyrene sample for creating a calibration curve, for example, Pressure Chemical Co.
．． or manufactured by Toyo Soda Kogyo Co., Ltd. with a molecular weight of 6
10", 2.IX 10"4 X 103, 1.7
5 x 10', 5. IX 10', 1. lXt
o', 3.9 XIO', 8.6X10ll, 2
XIO', 4.48 XIO', and it is appropriate to use at least 10 standard polystyrene samples. Further, an RI (refractive index) detector is used as a detector.

In addition, in order to accurately determine the molecular weight region of 10 3 to 2
μ-styragel 500, 103.
10', 106 union and Showa Denko's Shodex
KF-80M, KF-801, 803, 804
, 805 combination, KA-802, 803,
Combination of 804 and 805 or TS manufactured by Toyo Soda
Kgel GIOOOH, G2000H, G250
0H, G3000H, G4000H, G5000H
, G6000H, G7000H, and GMH are preferred.

The weight percent of the binder resin of the present invention having a molecular weight of 1000 or less is the molecular weight of 10.0 in the chromatogram by GPC.
00 or less, calculate the weight ratio with the cutout having a molecule i of 10,000 or more, and use the above-mentioned weight % of the T}IF insoluble content to calculate the weight % with respect to the entire binder resin.

As the constituent components of the resin of the present invention, various materials that are generally used as toner resins can be used as long as they can achieve the above-mentioned molecular weight distribution, but among them, vinyl monomers are used. Vinyl polymers, vinyl copolymers, and compositions of these polymers and copolymers were preferred.

Vinyl monomers applicable to the present invention include, for example, styrene, α-methylstyrene, p-crossstyrene, and its substituted substances: acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate. , dodecyl acrylate, octyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc., or their substituted monocarboxylic acids body;
Dicarboxylic acids with double bonds and their substituted substances, such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate, etc.; vinyl esters, such as vinyl chloride, vinyl acetate, vinyl benzoate, etc.; Vinyl monomers such as vinyl ketones such as vinyl methyl ketone, vinyl exyl ketone, etc.; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, etc. may be used alone or in combination of two or more. Among these, a combination of a styrene polymer and a styrenic copolymer is preferred.

The selection of the initiator, type of solvent, and reaction conditions when producing the resin of the present invention are important factors in obtaining the resin targeted by the present invention. Examples of initiators include penzoyl peroxide, 1,1-di(t-butylbaroxy)-3.3
．． 5-trimethylcyclohexane, n-butyl 4.4
-Organic materials such as di(t-butylperoxy)valerate, dicumyl peroxide, α,α′-bis(t-butylperoxydiisobrobyl)benzene, t-butylperoxycumene, di-t-butylperoxide, etc. Azo and diazo compounds such as peroxide, azobisisobutyronitrile, diazoaminoazobenzene, etc. can be used.

The binder resin for toner of the present invention can be partially crosslinked using a crosslinkable monomer.

As the crosslinkable monomer, compounds having two or more polymerizable double bonds are mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters with two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, and divinylaniline. 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.

In the method for producing the binder resin of the present invention, the first resin is produced by solution 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. Preferably, the monomers are polymerized in suspension. For 100 parts by weight of monomer for suspension polymerization, the amount of the first resin is lO~1
It is preferable to dissolve 20 parts by weight, preferably 20 to 100 parts by weight, and in suspension polymerization, the crosslinking agent is added in an amount of about 0.1 to 2. Preferably, O wt% is used. These conditions may vary slightly depending on the type of initiator and reaction temperature.

A case in which the first polymer is dissolved in a monomer and subjected to suspension polymerization to obtain the binder resin, a polymer obtained by suspension polymerization without dissolving the first polymer, and a case in which the first polymer is obtained by suspension polymerization without dissolving the first polymer. It is known that there is a difference in performance when used as a toner and when the toner is simply mixed, and the former produces better results, especially in terms of fixing properties.

Solution polymerization and suspension polymerization related to the present invention will be described below.

Solvents used in solution polymerization include xylene, toluene,
Cumene, cellosolve acetate, isobrobyl alcohol, benzene, etc. are used. In the case of styrene monomers, xylene, toluene or cumene are preferred. It is appropriately selected depending on the polymer to be polymerized. Initiators include di-tert-butyl peroxide, tert-butyl peroxybenzoate, penzoyl peroxide, 2,
2'-azobisisobutyronitrile, 2,2'-azobis(2.4-dimethylvaleronitrile), etc. are monomer 1.
0.1 part by weight or more (preferably 0.00 parts by weight)
(4 to 15 parts by weight). The reaction temperature varies depending on the solvent used, the initiator, and the polymer to be polymerized, but it is preferably carried out at 70°C to 180°C. In solution polymerization, 30 parts by weight of monomer per 100 parts by weight of solvent.
It is preferable to use 400 parts by weight to 400 parts by weight. Alternatively, it can be obtained by thermal polymerization.

Suspension polymerization is preferably carried out using 100 parts by weight or less of monomer (preferably 10 to 90 parts by weight) per 100 parts by weight of the aqueous solvent. As dispersants that can be used, polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, etc. are used, and there are appropriate amounts depending on the amount of monomer relative to the aqueous solvent, but in general, the aqueous solvent 100%
It is used in an amount of 0.05 to 1 part by weight. The polymerization temperature is suitably 50 to 95°C, but should be appropriately selected depending on the initiator used and the intended polymer. Any type of initiator can be used as long as it is insoluble or poorly soluble in water; for example, penzoyl peroxide, tert-butyl peroxyhexanoate, etc. can be used per 10 parts by weight of the monomer. 0.5~l
O parts by weight are used.

[Examples] Hereinafter, the present invention will be explained in detail with reference to Examples, but these are not intended to limit the present invention in any way.

Incidentally, all parts and percentages described in the examples indicate parts by weight and percentages by weight.

200 parts of cumene was placed in a reactor and heated to reflux temperature. To this was added 100 parts of styrene monomer and
- A mixture of 8 parts of butyl peroxide was added dropwise over 4 hours under cumene reflux. Furthermore, under reflux of cumene (146℃~
Polymerization was completed at 156°C) and cumene was removed. The obtained boristyrene was dissolved in THF and Mw=3700, M
w/Mn=2. 64, the molecular weight at the main beak of GPC was 3500, and Tg = 57°C.

30 parts of the above boristyrene is dissolved in the following monomer mixture,
A mixed solution was prepared.

The above mixed solution contains 0 partially saponified polyvinyl alcohol,
170 parts of water in which 1 part was dissolved was added to form a suspension dispersion.

Add 15 parts of water and introduce nitrogen through the nitrogen introduction pipe, and
The temperature was maintained at 45° C., and nitrogen was flowed so that the concentration of dissolved oxygen was 1.5 mg/j). In this state, the above dispersion liquid was added to the reactor, and a suspension polymerization reaction was carried out at a reaction temperature of 70 to 95°C for 9 hours. After the reaction was completed, the mixture was separated in a furnace, dehydrated, and dried to obtain a composition of polystyrene and styrene-n-butyl acrylate copolymer.

The composition has a uniform mixture of THF-insoluble components and THF-soluble components, and also contains polystyrene and styrene-acrylic acid n.
-Butyl copolymer was uniformly mixed.

The clove insoluble content of the obtained resin composition (24 mesh pass,
60 mesh resin composition powder) is 25%
Met. In addition, when the molecular weight distribution of THF-soluble components was measured, there were peaks at 0.4 million and 34 thousand positions, and Mn
=0.55 million, Mw=130,000, Mw/Mn = 24
, 25% had a molecular weight of 10,000 or less. Furthermore, the Tg of the resin
was 58°C.

Also, the content of benzaldehyde is 0. It was below 0.003%. Incidentally, the styrene monomer content was 0.018%.

10 g of the obtained resin was placed in a 200 cc sealed glass container and heated at 150° C. for 10 minutes, and then the odor was evaluated while heating.

Although a slight odor was felt, it was considered that there was no problem in practical use as a resin.

Therefore, the above resin was pulverized to an average particle size of about 10 microns and put into the color cartridge of a Canon copier FC-3 instead of toner, and the developing machine was used to form a uniform layer of resin particles on the paper surface. After adjusting and modifying the bias, transfer current, etc., the image was developed on a photoreceptor and transferred onto paper, and then passed through a fixing device, and the odor generated at that time was observed.

Odor evaluation was carried out by installing the above-mentioned copying machine in the center of a small room approximately 3 meters square, and continuously copying the fixation of resin particles onto paper using the above-mentioned method. When we conducted a sensory evaluation in the form of a panel test, in which we judged the odor by smelling it while changing the odor, very good results were obtained (results are shown in Table 1). Therefore, this resin can be applied as is to paper surface treatment by the above-mentioned means. Furthermore, it was determined that the present invention could also be applied to binder resins for toners as a similar application.

200 parts of cumene was placed in a Higashi JJ Tadasu reactor, and the temperature was raised to reflux temperature. The following mixture was added dropwise to the cumene over 4 hours under reflux.

Further, the polymerization was completed under cumene reflux (146 to 156°C), and cumene was removed. The obtained styrene-a-methylstyrene copolymer had Mw=4500, Mw/Mn=2
．． 8. In the GPC chart, the main beak was located at the molecular weight of 4400, and Tg was 63°C.

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

(Left below) Partially saponified polyvinyl alcohol is added to the above mixed solution.
170 parts of water in which 1 part was dissolved was added to form a suspension dispersion. Add 15 parts of water and do the same as in Example 1 to reduce the concentration of dissolved oxygen to 1.8B#! Closed. The above dispersion was added to the reactor in the same manner, and the reaction was carried out at a reaction temperature of 70 to 95°C for 9 hours. After the reaction was completed, the mixture was dehydrated and dried to obtain a composition of styrene-α-methylstyrene copolymer and styrene-2-ethylhexyl acrylate copolymer.

The THF-insoluble content of this composition was 32%. Also T
When the molecular weight distribution of the HF soluble component was measured, the molecular weight was 0.5.
It had peaks at the positions of 10,000, 40,000, and 20,000, and 20% of it was Mn=0,620,000, Mw=130,000+Mw/Mn=21+molecular weight of 10,000 or less. Also, the Tg of the resin is 58
It was ℃.

Further, the content of benzaldehyde in the resin is 0. 004
%, styrene monomer is 0. It was 0.035%.

When the same test as in Example 1 was conducted using the above resin, similarly good results were obtained.

200 parts of cumene was placed in a reactor and heated to reflux temperature. The following mixture was added dropwise to the cumene over 4 hours under reflux.

Further, the polymerization was completed under cumene reflux (146 to 156°C), and cumene was removed. Obtained styrene-methacrylate+7
"The rate copolymer has Mw-3900, Mw/Mn
= 2,6, had a main beak at the molecular weight position of 4100, and Tg = 60°C.

40 parts of the above styrene-methyl methacrylate copolymer was dissolved in the following monomer mixture to prepare a mixed solution.

Add 0% of the partially saponified polyvinyl alcohol to the above mixed solution.
170 parts of water in which 1 part was dissolved was added to form a suspension dispersion. Add 15 parts of water and add 1.5 parts of dissolved oxygen in the same manner as in Example 1.
It was set to 8rng/1. The above dispersion was added to the reactor in the same manner, and the reaction was carried out at a reaction temperature of 70 to 95°C for 9 hours. After the reaction is completed, the styrene-methyl methacrylate copolymer and the styrene-methyl methacrylic acid n-
A composition of butyl copolymer was obtained.

The THF-insoluble content of this composition was 35%.

In addition, the molecular weight distribution of THF-soluble components was measured and was found to be 0.4.
It has a peak at 10,000, 4,300,000, Mn=0,590,000, Mw
= 92,000, Mw/Mn = 16, and 32% had a molecular weight of 10,000 or less. Furthermore, the Tg of the resin was 60°C.

The penzaldehyde content of the above resin is 0. 0.003% and below, styrene monomer is 0.003%. 021%, Example l
Similar good results were obtained in the same odor evaluation.

A: 0.1% polyvinyl alcohol partially saponified product in the above mixture
170 parts of water was added to prepare a suspension and dispersion. water 1
Add 5 parts of dissolved oxygen to 1.5 m in the same manner as in Example 1.
g/jp. The above dispersion was added to the reactor in the same manner, and the reaction was carried out at a reaction temperature of 70 to 95°C for 9 hours. After the reaction was completed, the mixture was separated in a furnace, dehydrated, and dried to obtain a styrene-n-butyl acrylate copolymer composition.

The THF-insoluble content of this composition was 44 wt%.

In addition, when the molecular weight distribution of THF-soluble components was measured, there was a peak at the molecular weight position of 20,000, Mn = 0,800, Mw
= 28,000, Mw/Mn = 3.5, and the molecular weight of 10,000 or less was 21 wt%. Furthermore, the Tg of the resin is 56°C
Met.

Further, the content of benzaldehyde in the resin is 0. 003
% or less, styrene monomer is 0. When the odor evaluation was carried out in the same manner as in Example 1, the results were good in terms of odor, although the melting and fixing properties on paper were somewhat poor.

150 parts of cumene was placed in a K-mitachi reactor and heated to reflux temperature. The following mixture was added dropwise to the cumene over 4 hours under reflux.

Further, polymerization was completed under cumene reflux (146-156°C) L
,, Cumene was removed. The obtained styrene polymer was M
w=fli900, Mw/Mn=2. 3,
It has a main beak at a molecular weight of 7100, and Tg=
The temperature was 75°C.

30 parts of the above boristyrene is dissolved in the following monomer mixture,
A mixed solution was prepared.

Add 0% of the partially saponified polyvinyl alcohol to the above mixed solution.
170 parts of water in which 1 part was dissolved was added to make a suspension and dispersion. Add 15 parts of water and remove dissolved oxygen by 2.5 parts in the same manner as in Example 1.
The above dispersion was added to the reactor at a concentration of 3 mg/1, and reacted at a reaction temperature of 70 to 95°C for 9 hours. After the reaction was completed, the mixture was 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%.

In addition, the molecular weight distribution of the THF soluble component was measured and was 0.7.
It has a peak at 50,000, 40,000, and 30,000, Mn = 0.65 million, M
W=100,000, Mw/Mn=15, and 18% had a molecular weight of 10,000 or less. Furthermore, the Tg of the resin is 61'C, and the benzaldehyde content in the resin is o. oog%
, styrene monomer is 0. It was 056%.

When the above resin was subjected to the same odor test as in Example 1, it was judged that the resin was acceptable for practical use, although some people felt the odor.

200 parts of cumene was placed in a reactor and heated to reflux temperature. To this was added 100 parts of styrene monomer and
A mixture of 8 parts of butyl peroxide was added to 4 parts of cumene under reflux.
It dripped over time. Further, under reflux of cumene (146℃~1
Polymerization was completed at 56°C) and cumene was removed. The obtained boristyrene was dissolved in THF and Mw = 3700, Mw
/Mn=2. 64, the molecular weight at the main beak of GPC was 3500, and Tg = 57°C.

30 parts of the above boristyrene is dissolved in the following monomer mixture,
A mixed solution was prepared.

Add 0% of the partially saponified polyvinyl alcohol to the above mixed solution.
170 parts of water in which 1 part was dissolved was added to form a suspension dispersion.

Add 15 parts of water and do the same as in Example 1 to reduce the amount of dissolved oxygen to 3 parts.
．． The suspension polymerization reaction was carried out at 5 mg/i' for 9 hours at a reaction temperature of 70 to 95°C. After the reaction was completed, the mixture was separated in a furnace, dehydrated, and dried to obtain a composition of polystyrene and styrene-n-butyl acrylate copolymer.

The benzaldehyde content of the resin composition is 0.019
%, and the styrene monomer content was 0.07%, and when a panel test similar to that in Example 1 was conducted, many people were concerned about the odor, and it was judged that it could not be applied to paper surface treatment. It was also determined that it could not be applied as a binder resin for toner.

Then, 200 parts of cumene was placed in a slender reactor, and the temperature was raised to reflux temperature. To this was added 100 parts of styrene monomer and
A mixture of 8 parts of butyl peroxide was added to 4 parts of cumene under reflux.
It dripped over time. Further, under reflux of cumene (146℃~1
Polymerization was completed at 56°C) and cumene was removed. The obtained boristyrene was dissolved in THF and Mw = 3700, Mw
/Mn = 2.64, the molecular weight at the main beak of GPC was 3500, and Tg = 57°C.

30 parts of the above boristyrene is dissolved in the following monomer mixture,
A mixed solution was prepared.

Add 0% of the partially saponified polyvinyl alcohol to the above mixed solution.
170 parts of water in which 1 part was dissolved was added to form a suspension dispersion.

15 parts of water was added, and the concentration of dissolved oxygen was adjusted to 2.5 parts in the same manner as in Example 1. It was set at 8 mg/R. The above dispersion was added to the reactor in the same manner, and a suspension polymerization reaction was carried out at a reaction temperature of 70 to 95°C for 6 hours. After the reaction was completed, the mixture was separated in a furnace, dehydrated, and dried to obtain a composition of polystyrene and styrene-n-butyl acrylate copolymer.

The amount of benzaldehyde in the resin composition is 0. 015%
The styrene content was 0.03%. The result of the same panel test as in Example 1 was determined to be unacceptable as in Comparative Example 1.

This makes it possible to supply suspension polymer resins for use in toners.

[Effects of the Invention] With the wide spread of electrophotography, there is a demand for toners that are good against odors during hot melt fixing.In order to meet this demand, the present inventors have developed We discovered that the amount of polymerizable monomer oxides, especially aldehydes, remaining in the binder resin has a large effect, and in order to achieve this reduction, it is necessary to control the amount of dissolved oxygen in water, especially during suspension polymerization. We found that this is essential.

Claims (2)

[Claims] (1) In the binder resin for toner obtained by polymerizing a monomer composition containing a polymerizable monomer containing at least 50% by weight of styrene monomer and a polymerization initiator, the content of aldehydes is 0.01% by weight. % or less. (2) In a method for producing a binder resin for toner by polymerizing a monomer composition containing a polymerizable monomer containing at least 50% by weight of styrene monomer and a polymerization initiator, the amount of dissolved oxygen is 0.25 mg/ A binder resin for toner, characterized in that a monomer composition is suspension polymerized in an aqueous medium of 1 or less to produce a styrenic resin having an aldehyde monomer content of 0.01% by weight or less. Production method.