JPH0450216A - Ab type block copolymer and utilization thereof - Google Patents

Abstract

PURPOSE:To obtain the subject resin, having a specific structure and a wide temperature range for enabling fixing, excellent in blocking resistance and useful as toners for electrophotography, electrostatic recording, etc. CONSTITUTION:The objective copolymer expressed by formula I. {M is formula II or III [M<1> is polymer constituent units composed of (A) 70-100wt.% monomer selected from styrene-based monomers and methyl methacrylate and (B) 0-30wt.% 3-4C alkyl (meth)acrylate; M<2> is polymer constituent units composed of 0-50wt.% component (A) and 50-100 wt.% component (B); n is 20-200; m is 15-190, provided that m<=n]; R<1> is 1-10C hydrocarbon residue; R<2> is H or R<1>; R<3> is benzyl or formula IV (R<4> is R<1>; R<5> is R<2>; R<6> is 1-18C hydrocarbon residue), provided that segments (M<1>)n and (M<2>). contain a monomer M<3> selected from maleic acid (anhydride), 1-10C mono- or dialkyl maleate and (meth)acrylic acid in an amount of 1-15wt.% based on the total amount of (M<1>+M<2>+M<3>) in addition to the aforementioned definition}

Description

Detailed description of the invention [Background of the invention] It relates to copolymers.

<Prior Art and its Problems> Conventionally, electrophotography consists of the following three steps, as described in the specifications of US Pat. No. 2,297,691 and US Pat. No. 2,357,809. ■A photoconductive insulating layer is uniformly charged, the layer is exposed to light, and the charge on the exposed area is erased to form an electrical latent image, which is then coated with toner. Electrically attached and visualized fine powder with electrical charge (development process)
.

■Transfer the obtained visible image to a transfer material such as transfer paper (transfer process). ■ Fixing the visible image by heat, pressure or other fixing methods (fixing process).

In such electrophotographic methods, the methods conventionally used for fixing are methods called oven fixing method and heat roller constant fixing method. Among these methods, the heat roller fixing method has very good thermal efficiency because the surface of the heating roller and the toner image surface of the sheet to be fixed are brought into pressure contact, and is widely used from low-speed copying to high-speed copying.

However, this heat roller constant deposition method has the disadvantage that when the heating roller surface and toner image surface come into contact, the toner remains attached to the heating roller surface and contaminates the subsequent transfer paper, which is apt to cause the so-called offset phenomenon. have. This offset phenomenon occurs when the heating roller surface temperature is too low and the toner on the heating roller is not completely melted, resulting in toner remaining on the roller (low-temperature offset phenomenon), and when the heating roller surface temperature is too high and the toner remains on the heating roller. Two cases are known in which the toner remains on the roller because the melt viscosity of the toner is too low (high temperature offset phenomenon). Therefore, in general, in the heat roller constant fixing method, the minimum temperature required for fixing (minimum fixing temperature) is higher than the low temperature offset temperature, and the fixable temperature range is above the minimum fixing temperature and below the high temperature offset temperature. The settings are as follows.

Currently, there is an increasing demand for high-speed fixing, colorization, and energy saving for electrophotography, and therefore a lower minimum fixing temperature (low-temperature fixing performance) is desired. In order to obtain stable fixing performance even when the internal temperature of the machine increases due to operation or the like, it is also desired to raise the low-temperature offset temperature. Additionally, with the widespread use of copying machines, it is also desired that toner maintain its powder form without agglomerating (blocking) in the copying machine even under relatively harsh temperature and environmental conditions (blocking resistance). There is.

Thermal properties such as melting properties and heat resistance properties of these toners are controlled by the toner resin, which is the main component and accounts for about 60 to 98% by weight of the toner components.

Therefore, it is necessary to design the molecule of a toner resin that satisfies the above-mentioned requirements.

Various attempts have been made for this purpose.

The most widely used styrene-(meth)acrylic acid ester copolymer toner resin is not suitable for the above purpose because molecular design such as molecular weight control is more difficult than using normal radical thermal polymerization methods. is the current situation.

On the other hand, there have been attempts to use polyester resins, but this resin not only has problems such as difficulty in controlling the softening point, but also has a negative impact on charging performance due to the inherent hygroscopicity of this resin. (``Recent Development and Practical Application of Electrophotographic Systems and Toner Materials'' (1985, Nihon Kagaku Information Co., Ltd., p. 180 et seq.), is not widely used.

[Summary of the invention]

Summary of the Invention An object of the present invention is to solve the above problems and provide a toner resin that has a wider fixable temperature range and also has excellent blocking resistance.

That is, the AB type pro-tsuk copolymer according to the present invention is
It is represented by the following general formula (I).

(In formula (I), M and R1-R3 are defined as below.

(1) M is →M2←M1← or m n polymer part, and Ml and M2 and m and n
are defined as follows.

Ml: 70 to 100% by weight of at least one monomer selected from styrene monomers and methyl methacrylate, and methyl acrylate and alkyl methacrylate (however, the number of carbon atoms in the alkyl group is 3 to 4) A polymer structural unit formed from 0 to 30% by weight of at least one selected monomer.

M2: 0 to 50% by weight of at least one monomer selected from styrene monomers and methyl methacrylate, and methyl acrylate and alkyl methacrylate (however, the number of carbon atoms in the alkyl group is 3 to 4) A polymeric structural unit composed of 50 to 100% by weight of at least one selected monomer.

n and man are natural numbers from 20 to 200, and m is 1
It is a natural number from 5 to 190, and m≦n.

(li) R1 represents a hydrocarbon residue having 1 to 10 carbon atoms.

(111) R2 represents a hydrogen atom or a hydrocarbon residue having 1 to 10 carbon atoms.

(Here, R4 is a hydrocarbon residue having 1 to 10 carbon atoms, R
5 is a hydrogen atom or a hydrocarbon residue having 1 to 10 carbon atoms,
R6 represents a hydrogen atom or a hydrocarbon residue having 1 to 18 carbon atoms, respectively.

(V) Segments (Ml) and (M2)n
In addition to the above definition, m is 1 to 1 monomer M3 selected from the following group on at least one of both segments based on the total of M1 + M2 + M3.
It contains 5% by weight.

(a) A maleic acid compound selected from maleic acid, maleic acid mono- or dialkyl ester (however, the alkyl group has 1 to 10 carbon atoms), and maleic anhydride.

(b) Acrylic acid or methacrylic acid.

Further, the toner for electrophotography according to the present invention, which utilizes the above-mentioned copolymer, has the above-mentioned AB type block copolymer as a resin component.

<Effects> The block copolymer of the above formula (I) according to the present invention has a high degree of freedom in molecular design in order to exhibit the physical properties necessary as a toner resin, so the above object can be easily achieved. .

That is, the AB type block copolymer of the present invention does not cause blocking in an atmosphere of 50° C. or lower, that is, it has excellent blocking resistance, while it can be easily fixed in an atmosphere of 120° C. or higher, that is, it has excellent low-temperature fixing properties. Moreover, the resin for toner does not cause high temperature offset phenomenon at temperatures below 200° C., that is, it has excellent high temperature offset properties. The excellent blocking resistance of this block copolymer is thought to be due to the fact that the hard chains constituting the continuous phase have a Tg of 50°C or more, so the resin surface does not soften.On the other hand, the excellent low-temperature fixability This is thought to be because the soft chains forming the dispersed phase function as a plasticizer. Furthermore, the excellent high-temperature offset property is thought to be due to the fact that the copolymerized fixing property improving monomer (M3) prevents the entire block copolymer from rapidly decreasing in melt viscosity at a high temperature of about 200°C. This block copolymer can be widely used in fields where a wide fixing temperature range and blocking resistance are simultaneously required.

Specifically, black and white toner, color toner, toner for page printers, inkjet ink, printer ribbon ink, powder coating, solid coating, ink additive, toner additive, paint additive, resin phase. Examples include solubilizers, hot melt adhesives, hot melt adhesives, polymer alloys, and the like.

In addition, the fact that the fixing temperature range is wider in the present invention is that
As mentioned above, this means that either the minimum fixing temperature is lower, the high temperature offset temperature is higher, or both are satisfied.

[Detailed Description of the Invention Basic Structure of Block Copolymer] The block copolymer according to the present invention is represented by general formula (I).

(The definitions of each substituent are as described above) In formula (1), R1 (R2) NC(-5)- and -R3
is a residue derived from a polymerization initiator (details will be described later), and M is a part forming the main body of the block copolymer.

M, which forms the main body of the block copolymer, is a block of Ml, i.e. (Ml) and a block of M2, i.e. (M2).
It is the above-mentioned block that consists of these blocks, and the respective monomer species are also described above (details will be described later), but the contribution of these blocks to the block copolymer of the present invention is as follows.

That is, the block copolymer represented by formula (I) of the present invention basically consists of a relatively hard polymer chain (Ml).
(hard chain) and relatively soft polymer chain (M2) (
It is an AB type block copolymer consisting of soft chains). M
l is a monomer (hard monomer) that can form a polymer with a glass transition point (Tg) of 60°C or more when used alone, and a polymer that can form a polymer with a Tg of 0°C or more and less than 40°C when used alone. Consisting of a mixture of vine monomers (soft monomers), 70-100% by weight of hard monomers (one or more types) and 0-30% by weight of soft monomers (one or more types) It is more than that. Here, if the proportion of the hard monomer is less than 70% by weight or if the proportion of the soft monomer is more than 30% by weight, the low-temperature fixing properties will be improved, but the blocking resistance will be lowered, which is not preferable.

Among them, hard monomers (one or more types) are 70 to 90
% by weight and the soft monomer (one or more types) is 1
A mixture of 0 to 30% by weight is preferable from the viewpoint of the balance between low temperature fixing properties and blocking resistance of the block copolymer to be synthesized.

Similarly, M2 consists of a soft monomer or a mixture of a hard monomer and a soft monomer, with the hard monomer (one or more) being 0 to 50% by weight and the soft monomer ( 50 to 100% by weight of one kind or two or more kinds. If the proportion of the hard monomer is more than 50% by weight or if the proportion of the soft monomer is less than 50% by weight, the anti-blocking property will be improved, but the low-temperature fixing property will be deteriorated, which is not preferable. On the other hand, if the proportion of hard monomers is less than 50% by weight or the proportion of soft monomers exceeds 50% by weight,
Although low-temperature fixability is improved, blocking resistance is decreased, which is not preferable. Among these, a mixture consisting of 0 to 40% by weight of hard monomers (one or more types) and 60 to 100% by weight of soft monomers (one or more types) is synthesized. This is preferable from the viewpoint of the balance between low temperature fixing properties and blocking resistance of the block copolymer.

In formula (I), n and m represent the lengths of the hard chain and soft chain, ie, the degree of polymerization, respectively. Generally, in this block copolymer, as n increases, the ratio of hard chains increases, and blocking resistance improves, but low-temperature fixability decreases, while as n decreases, the ratio of hard chains decreases, There is a tendency that the low-temperature fixing property increases, although the blocking resistance decreases. Similarly, as m increases, the proportion of soft chains increases, and blocking resistance decreases, but low-temperature fixing properties improve, while as m decreases, the proportion of soft chains decreases, and blocking resistance improves. There is a tendency for low-temperature fixability to decrease.

In the present invention, when n is less than 20, the low temperature fixing property improves, but the blocking resistance decreases, which is not preferable;
If the amount is in excess, blocking resistance will improve, but low-temperature fixing properties will deteriorate, which is not preferable.

From this point of view, n is preferably 25 to 150, and 3
0 to 100 is more preferable. On the other hand, if m is less than 15, blocking resistance will improve but low-temperature fixing properties will decrease, which is undesirable.On the other hand, if m exceeds 190, low-temperature fixing properties will improve, but blocking resistance will decrease, which is not preferable. do not have. From such a viewpoint, m is preferably 20 to 140, more preferably 25 to 90.

Regardless of n and m, it is necessary that n ≧ m because the morphology of this block copolymer requires that the hard chains become the continuous phase and the soft chains become the dispersed phase. . This is because if n<m, the soft chains will become a continuous phase and the blocking resistance will be significantly reduced. In addition, it is often preferable that the block copolymer of the present invention has a microphase-separated structure with greatly different compositions of polymer chains M and M2.

Details of the monomer species of the block copolymer having the above characteristics are as described below.

Modification of copolymer block> The basic structure of the block copolymer according to the present invention is as described above, but the present invention can be modified by modifying blocks (M) and (
n on one or both of M2)
A specific monomer (M3) is further copolymerized, and the fixing properties are improved by its contribution.

This fixing property improving monomer M3 was selected in order to increase the high temperature offset temperature without reducing the low temperature fixing properties of the synthesized block copolymer at all or very much.

From this point of view, it is desirable that the fixability improving monomer (M3) be present in a specific amount.

That is, if the monomer M3 is less than 1% by weight based on the total amount of M1+M2+M3, hardly any effect can be expected, whereas if it exceeds 15% by weight, the low-temperature fixing properties will deteriorate, which is not preferable. From the viewpoint of the balance between high-temperature offset properties and low-temperature fixing properties of the block copolymer, the proportion of the low-temperature fixing property improving monomer is preferably 3 to 1% by weight. Note that M is (Ml
) and (or) even if present in (M2),
The ratio of hard monomer to soft monomer in each of M and M2 is based on the total amount of both (i.e., M-
(excluding 3). Furthermore, the degrees of polymerization n and m of each block are also shown for those not containing M3. In defining the present invention, the monomer M
In requirement (V) regarding 3 segment (Ml)
This is why we said "in addition to the above definitions" for and (M2).

The fixability improving monomer M3 has a hard chain [(Ml)] and a soft chain (M2))n
m
Although it is effective even if it is present in either one or both, the effect is greater when it is present in a higher concentration in the soft chain, and it is even more effective when it is present only in the soft chain, so it is preferable.

Details of the fixability improving monomer method M3 are also as described below.

[Production of block copolymer]

Polymerization initiator and its polymerization mechanism> As described above, the block copolymer according to the present invention has a residue derived from a polymerization initiator.

That is, the polymerization initiator used in the present invention is a dithiocarbamate polymerization initiator, which has the ability to initiate radicals by light energy, and specifically has the general formula (
0).

).

Here, both R1 and R2 are preferably hydrocarbon residues having 1 to 4 carbon atoms, particularly those having 2 or 3 carbon atoms, from the viewpoint of polymerization rate and polymerization controllability. Here, R4 is a hydrocarbon residue having 1 to 5 carbon atoms, R5 is a hydrogen atom or a hydrocarbon residue having 1 to 5 carbon atoms, and R6 is a carbon Numbers 1-5
Hydrocarbon residues are preferred, especially R4, R5 and R6
It is preferable that both are hydrocarbon residues having 1 to 3 carbon atoms.

Specific examples of such dithiocarbamate polymerization initiators include the following.

(Here, R1, R, and R3 are represented by the general formula (1). Generally, the dithiocarbamate compound serving as an initiator for these is synthesized in good yield from a halide and an equivalent amount of sodium N,N-dialkyldithiocarbamate. For example, by reacting 1 mole of benzyl chloride with 1 mole of sodium NN-diethyldithiocarbamate, approximately 1 mole of benzyl-N,N-diethyldithiocarbamate is obtained.

Note that even if some of the hydrogens on the benzene ring in the general formula (0) are replaced with halogens, hydrocarbon groups, especially lower hydrocarbon groups, etc., significant changes in physical properties will not occur substantially as described above. These may be substituted as such, as they are not allowed. Therefore, the AB type block copolymer according to the present invention also includes such substituted copolymers.

Such an initiator is called an iniferter, and is radically dissociated by light and has the ability to initiate radical polymerization.
It is well known that polymerization reactions proceed in a living manner due to the combination of chain transfer ability and termination ability (``Polymer Journal'', Vol. 16, Vol. 6).
(1984), pp. 511 et seq.).

In the initiator of formula (0), the sulfur-carbon sigma bond of 5-R3 is radically dissociated by light energy, and polymerization proceeds so as to insert a monomer between 5-R3.

The block copolymer of the present invention can be synthesized by photopolymerization in two steps using such a polymerization initiator. That is, a monomer mixture of constant composition (e.g. M1
This initiator is used to complete the photopolymerization (forming monomer) (first step), and then a monomer mixture with a different composition (
Therefore, by completing the photopolymerization (second step) of the M2-forming monomer) using the polymer itself obtained as described above as a polymer initiator, AB of formula (1) is obtained. A type block copolymer is obtained.

The degree of polymerization (molecular weight) of each segment of the block copolymer can be controlled by the molar ratio of the initiator to the monomer. For example, when 1 mol% of benzyl-N,N-diethyldithiocarbamate is added to methyl methacrylate whose monomer molecular weight is 100, the number average molecular weight is approximately 10.
,000, and the weight average molecular weight is about 20,000, which corresponds to a number average degree of polymerization of 100. Similarly, in the case of addition of 0.1 mol%, the values are approximately 100,000 and approximately 20,000, respectively, which correspond to a number average degree of polymerization of 1000 (Kobunshi Vol. 38, No. 8 (1989) , 84th
1 page).

In the second step as well, it is possible to control the degree of polymerization (molecular weight) by controlling the molar ratio of the polymer initiator and monomer.

Monomer> The monomer M1 is mainly a hard monomer and may contain a small amount of a soft monomer, and the monomer M2 consists only of a soft monomer or a mixture of this and a hard monomer. Contains an appropriate amount of.

The hard monomer is selected from the group consisting of styrenic monomers and methyl methacrylate. Specific examples of the styrenic monomer include styrene, core and/or side chain substituted styrene, such as α-methylstyrene, p-methylstyrene, p-chloromethylstyrene, and 0-aminostyrene. It will be done. As the hard monomer, styrene and methyl methacrylate are preferred, with styrene being particularly preferred.

The soft monomer is selected from the group consisting of methyl acrylate and alkyl methacrylate (wherein the alkyl group has 3 to 4 carbon atoms). Here, "alkyl" includes linear and branched chains, as well as n-1i-1sec- and t-isomers, respectively. Preferred among these are methyl acrylate and butyl methacrylate, and particularly preferred is butyl methacrylate.

In addition, each segment contains a small amount of other (meth)acrylic acid ("(meth)acrylic acid" is a general term for acrylic acid and methacrylic acid), (meth)acrylic acid ester, maleic acid derivative, etc. Since the addition of sexually unsaturated monomers does not affect the melt properties and blocking resistance, the combined use of such monomers is permissible in the present invention.

On the other hand, the fixing property improving monomer M3 is (a) maleic acid selected from maleic acid, maleic acid mono- or dialkyl ester (the alkyl group has 1 to 10 carbon atoms), and maleic anhydride. and (b)acrylic acid or methacrylic acid.

Preferred among these are maleic acid monoalkyl esters, particularly those in which the alkyl group has 2 to 8 carbon atoms, such as monoethyl maleate, monobutyl maleate, and 7-2-ethylhexyl maleate. In addition, even if other ethylenically unsaturated monomers such as vinyl acetate, vinyl chloride, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, butyl methacrylate, etc. are copolymerized, a small amount, e.g. Up to about 5% by weight of this fixing property improving monomer does not adversely affect the blocking resistance and fixing properties of the resulting block copolymer, so these monomers may be used in combination.

Polymerization mode> The AB type block copolymer according to the present invention is usually synthesized by photopolymerization using ultraviolet light of a wavelength necessary for decomposing the dithiocarbamate compound or generating radicals, for example, 300 to 500 nm. . As long as light reaches the dithiocarbamate group, which is the initiation site, through the polymerization reaction, this polymerization can be carried out in any form: bulk, solution, suspension, dispersion, slurry, emulsion, or gas. I don't mind. As the solvent for production by solution polymerization, it is preferable to use a solvent that does not have characteristic absorption of ultraviolet rays with a wavelength of 300 to 500 nm, has a small chain transfer constant, and can dissolve monomers and polymers well. Such preferred solvents include, for example, benzene, toluene, xylene, ethylbenzene, acetone,
Methyl ethyl ketone, ethyl acetate, methyl cellosolve,
Examples include ethyl cellosolve, tetrahydrofuran, dimethylformamide, methanol isopropyl alcohol, butanol, hexane, heptane, and water.

The polymerization atmosphere and polymerization temperature are preferably the same as those for normal radical polymerization, and specifically, a temperature of 10 to 150°C in an inert gas such as nitrogen or argon is preferred.

Since the terminal dithiocarbamate group in the synthesized AB type block copolymer exists without being deactivated just through the polymerization reaction, it is possible to further add a polyfunctional radically polymerizable monomer such as divinylbenzene. It is also possible to obtain a crosslinked product by impregnating the block copolymer with photopolymerization.

The dithiocarbamate group can impart pharmacological activities such as radiation resistance, chelate-forming ability, and herbicidal properties to the copolymer, and by treating the dithiocarbamate with oxygen, the block copolymers can be cross-linked with sulfur. It is also possible to introduce

Furthermore, in the present invention, by treating the dithiocarbamate groups at both ends of the synthesized block copolymer, both ends of the block copolymer can be inactivated against ultraviolet rays. For example, the block copolymer has a wavelength of 220
Irradiate with high-energy electromagnetic radiation below na or heat at 250℃
The block copolymer can be inactivated against ultraviolet rays by treatment at higher temperatures for several minutes or by treatment with an acidic or basic solution.

Inactivation can also be achieved by further photopolymerizing after adding the ultraviolet absorbing group-containing monomer.

Furthermore, in the present invention, it is also possible to substitute the ends of the block copolymer by adding a reagent with a large chain transfer constant, such as a thiol, while irradiating the synthesized block copolymer with ultraviolet rays. be.

[Example of practical experience]

The following experimental examples illustrate the invention in further detail. The present invention is not limited to these examples.

Production Example A> A 500 m1 separable flask made of Pyrex glass with a stirrer and a condenser was installed at a distance of 10 cm from a high-pressure mercury lamp with an output of 400 W (H-400PL manufactured by Toshiba Lightic) in a constant temperature bath at 50 °C. ,
Stynone 62g1 Butyl acrylate 38g1 Benzyl-N,N-diethyldithiocarbamate (BDC)7.
2 g of toluene and 200 g of toluene were charged, and while a trace amount of nitrogen gas was supplied, ultraviolet rays were irradiated using the mercury lamp for 20 hours to effect photopolymerization. One liter of methanol was added to this polymer solution to precipitate the polymer, and the precipitate was dried for 15 hours in a vacuum dryer kept at 90°C.

The obtained polymer will be used as polymer initiator A in the next step, and its yield, number average molecular weight (Mn), weight average molecular weight (M w ), and polymerization dispersion determined by gel permeation chromatography are degree (Mw/Mn),
Also, the glass transition point (Tg) is as shown in Table 1.

Production Example B-J> The same operation as in Production Example A was performed using the raw material composition shown in Table 1 to produce a polymer to be used as the polymer initiator B-J. The yield and identification results of these polymers are as follows.
As shown in Table 1.

Production Example 1> Polymer initiator A30f produced in Production Example A and styrene 12 were placed in a polymerization tank consisting of the same equipment as that used in Production Example A.
g1 50 g of butyl methacrylate, 8 g of monobutyl maleate and 210 g of toluene were added and dissolved well, then
Photopolymerization was carried out for about 20 hours while supplying a trace amount of nitrogen gas, and 2 liters of methanol was added to the obtained polymerization solution to precipitate the polymer, and the resulting precipitate was dried under reduced pressure at 90°C. It was dried in a container for 15 hours. The obtained polymer was designated as block copolymer (1), and its yield, Mn, Mw
, Mw/Mn, and Tg are shown in Table 2.

Preparation Examples 2 to 5 Block copolymers (2 to 5 )～(6)
was synthesized. The polymer initiator used, the yield of the obtained block copolymer, and M n .

Mw, Mw/Mn and Tg are as shown in Table 2.

Production Examples 7 to 17> The polymer initiators and monomers shown in Table 3 were used instead of 30 g of polymer initiator A, 32 g of styrene, 20 g of butyl methacrylate, and 8 g of monobutyl maleate in Production Example 1. Polymerization was carried out in the same manner as in Production Example 1, and the obtained polymers were used as block copolymers (7) to (17), and their yields, Mn, Mw, Mw/Mn, and Tg are shown in Table 3. Example> In the usage examples 1 to 14 below, the compositions shown in Table 4 are mixed using a Henschel mixer, then melt-kneaded using a twin-screw extruder, cooled, and then subjected to the usual pulverization and classification processes to produce toner particles with an average particle size of 11 μm. A resin was prepared.

39 parts of each of the above toners and 1261 parts of resin-coated iron powder
A commercially available electrophotographic copying machine (the photoreceptor is amorphous selenium, the rotation speed of the fixing roller is 255 m+m/see, the heat roller temperature in the fixing device is variable, and the oil coating device is Images were produced using the removed sample), and the lowest fixing temperature, low temperature offset temperature, and high temperature offset temperature were evaluated. Regarding blocking resistance, each toner was tested at 50°C and relative humidity 40%.
The degree of aggregation was evaluated when the sample was left for 24 hours under these conditions. Each evaluation result is also shown in Table 4.

Reference Examples and Comparative Examples> In Comparative Examples 1 to 4 and Reference Examples 1 to 3, the same operation as in the usage example was performed with the composition in Table 5, and the average particle size was 11 μm.
A developer was prepared with the same toner resin and iron powder composition as in the usage example. The minimum fixing temperature, low-temperature off-hit temperature, high-temperature offset temperature, and blocking resistance of these developers were evaluated in the same manner as in the usage examples, and the results are also shown in Table 5.

Claims (1)

[Claims] 1. AB type block copolymer represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In formula (I), M, R^1 to R^3 are defined as below. (i) M is ▲mathematical formula, chemical formula , tables, etc. ▼ or ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ A block copolymer part represented by M^1 and M^2 and m
and n are each defined as below. M^1: 70 to 100% by weight of at least one monomer selected from styrenic monomers and methyl methacrylate
and 0 to 30% by weight of at least one monomer selected from methyl acrylate and alkyl methacrylate (wherein the alkyl group has 3 to 4 carbon atoms). M^2: 0 to 50% by weight of at least one monomer selected from styrene monomers and methyl methacrylate, and methyl acrylate and alkyl methacrylate (however,
A polymer structural unit composed of 50 to 100% by weight of at least one monomer selected from the group consisting of an alkyl group having 3 to 4 carbon atoms. n and m: n is a natural number from 20 to 200, and m is 1
It is a natural number from 5 to 190, and m≦n. (ii) R^1 represents a hydrocarbon residue having 1 to 10 carbon atoms. (iii) R^2 represents a hydrogen atom or a hydrocarbon residue having 1 to 10 carbon atoms. (iv) R^3 is a benzyl group or ▲ mathematical formula, chemical formula,
There are tables etc. ▼ (Here, R^4 is a hydrocarbon residue with 1 to 10 carbon atoms, R^5 is a hydrogen atom or a carbon number of 1 to 1
0 hydrocarbon residue, R^6 is a hydrogen atom or carbon number 1
~18 hydrocarbon residues are shown, respectively). (v) Segments (M^1)_n and (M^2)_m
In addition to the above definition, monomer M^3 selected from the following group is added to at least one of both segments M^1+M^
The content is 1 to 15% by weight based on the total of 2+M^3. (a) A maleic acid compound selected from maleic acid, maleic acid mono- or dialkyl ester (however, the alkyl group has 1 to 10 carbon atoms), and maleic anhydride. (b) Acrylic acid or methacrylic acid. 2. A toner for electrophotography, comprising the AB type block copolymer according to claim 1 as a resin component.