JP3066020B2 - Toner binder for electrophotography - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a toner binder for electrophotography.

[0002]

2. Description of the Related Art In an electrophotographic process using a powdery dry toner, a method using a contact heating type fixing device (heat roll) to fix a toner transferred onto paper or the like,
A method in which a film or belt is interposed between a heating element and paper (for example, JP-A-4-70688 and JP-A-4-70688)
No. 12558) has been widely adopted. In this method, it is desirable that the minimum fixing temperature (hereinafter abbreviated as MFT) is low (low-temperature fixability), and the temperature at which hot offset occurs on the heat roll surface, film or belt (hereinafter abbreviated as HOT) is high. Is desirable (hot offset resistance). In order to obtain a clear image, a toner having a high triboelectric charge is preferable (charging characteristics).

Conventionally, polystyrene resins, styrene-acrylic copolymers, polyester resins, epoxy resins, and the like have been generally used as binder components of the dry toner. Among them, polystyrene resins are preferred in terms of performance such as grindability and chargeability and cost. Based resins and styrene-acrylic resins are widely used. In order to satisfy the low-temperature fixing property and the hot offset resistance, many methods have been proposed for improving the resin by widening the molecular weight distribution of the resin. As a method of expanding the molecular weight distribution, a method of using a vinyl-based crosslinking agent for vinyl-based resins (JP-A-61-215558, JP-A-63-44665, and JP-A-63-22)
No. 3014, JP-A-4-202307),
In the molecular weight distribution, a binder having two peaks in a high molecular weight part and a low molecular weight part (JP-B-63-32180)
Or a binder obtained by crosslinking a carboxyl group-containing vinyl resin with a glycidyl compound (JP-A-6-11890, JP-A-6-18990).
-222612) has been proposed.

[0004]

However, as described above, in the case of a binder containing only a crosslinked structure or a binder consisting of only a high molecular weight compound and a low molecular weight compound, the kneaded portion in the toner-forming step causes the formation of a crosslinked portion or a high molecular weight compound. Since the molecular portion is severely cut and the melt elasticity of the toner tends to be low, a lot of crosslinking components and high molecular weight components will be used to maintain hot offset resistance, and the melt viscosity of the resin will increase, The low-temperature fixability of the toner becomes insufficient. In addition, in the conventional method of crosslinking by utilizing the reaction of the functional group in the polymer, if the amount of the functional group is increased to increase the HOT and the degree of crosslinking of the binder is increased, the amount of the polar group is increased, and the charge of the binder is increased. Insufficient properties. As described above, in the conventional technology, in recent years, demands for high image quality of copiers, facsimiles, and printers, and trends for more hot offset resistance and lower-temperature fixing properties due to faster and smaller hardware are increasing. It is hard to say that we can handle it enough.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is a toner binder having excellent charging characteristics when formed into a toner. As a result of intensive studies aimed at obtaining a toner binder having excellent fixability, the present invention has been achieved. That is, the present invention comprises a styrene-acrylic resin (A) having a reactive functional group (a) and a styrene resin or a styrene-acrylic resin (B) having a functional group (b) that reacts with (a). In the electrophotographic toner binder, (A) is composed of a high molecular weight substance (C) having a weight average molecular weight of 200,000 to 2,000,000 and a low molecular weight substance (D) having a weight average molecular weight of 3000 to 50,000. The equivalent weight (Eq / g) of (a) in ()) is 50% or less of the equivalent weight of (a) in (C), (a) is an acid anhydride group,
An electrophotographic toner binder which is a reactive functional group selected from the group consisting of a hydroxyl group, an isocyanate group, an amino group and a glycidyl group.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The reactive functional group (a) of the present invention is usually an acid anhydride group, a hydroxyl group, an isocyanate group, an amino group, or a glycidyl group. Of these, preferred are an acid anhydride group, a hydroxyl group and an amino group.
More preferred are acid anhydrides. As a method of introducing (a) into a resin to obtain (A), a method of copolymerizing a vinyl monomer having (a) with a styrene monomer and an acrylic monomer is preferable. Examples of the vinyl monomer having an acid anhydride group include maleic anhydride, itaconic anhydride, crotonic anhydride and the like. Of these, maleic anhydride and itaconic anhydride are preferred. Examples of the vinyl monomer having a hydroxyl group include, for example, 2
-Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene mono (meth) acrylate, allyl alcohol and the like. Preferred among these is 2-hydroxy (meth) acrylate. Examples of the vinyl monomer having an isocyanate group include m-isopropenyl-
α, α-dimethylbenzyl isocyanate, methacryloyl isocyanate, 2-isocyanateethyl methacrylate and the like. Of these, m-isopropenyl-α, α-dimethylbenzyl isocyanate is preferred. Examples of the vinyl monomer having an amino group include amino group-containing styrene (such as 1-styrylmethylimidazole), amino group-containing (meth) acrylate (such as dimethylaminoethyl (meth) acrylate), and amino group-containing (meth) acrylamide (dimethylaminopropyl). (Meth) acrylamide and the like. Among these, amino group-containing (meth) is preferable.
Acrylate. Examples of the vinyl monomer having a glycidyl group include glycidyl (meth) acrylate,
Β-methyl glycidyl (meth) acrylate, allyl glycidyl ether, and the like. Among these, glycidyl (meth) acrylate is preferred.

The styrene monomer used for the styrene-acrylic resin (A) having (a) includes styrene, α-methylstyrene, p-methoxystyrene, p-methoxystyrene,
Examples include hydroxystyrene and p-acetoxystyrene. Acrylic monomers include butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
Alkyl (meth) acrylates having an alkyl group of 1 to 18 carbon atoms, such as lauryl (meth) acrylate and stearyl (meth) acrylate, divinylbenzene, ethylene glycol di (meth) acrylate, and propylene glycol di (meth) Examples include acrylate, 1,6-hexanediol di (meth) acrylate, and divinyl compounds such as divinyltoluene. Further, other vinyl monomers other than these styrene monomers and acrylic monomers may be copolymerized. Other vinyl monomers include vinyl esters such as vinyl acetate; vinyl ethers such as vinyl ethyl ether; α
-Aliphatic hydrocarbon vinyls such as olefins, isoprene and butadiene; and (meth) acrylonitrile.

The functional group (b) which reacts with (a) includes, for example, when (a) is an anhydride group, and (b) includes a hydroxyl group, an isocyanate group, and an amino group. Among these, a hydroxyl group and an amino group are preferred. When (a) is a hydroxyl group, (b) includes an isocyanate group, an acid anhydride group and a glycidyl group. Preferred among these are an isocyanate group and an acid anhydride group. When (a) is an amino group, (b) includes an isocyanate group and an acid anhydride group. Among these, isocyanate groups,
It is an acid anhydride group. When (a) is an isocyanate group,
(B) includes a hydroxyl group, an amino group, a carboxyl group, a glycidyl group, an acid anhydride group and the like. Among these, a hydroxyl group and an amino group are preferred. When (a) is a glycidyl group, (b) includes a carboxyl group, a hydroxyl group and an acid anhydride group. Preferred among these is a carboxyl group.

The styrene-acrylic resin (A) comprises a high molecular weight compound (C) and a low molecular weight compound (D), and the weight average molecular weight of (C) is 200,000 to 2,000,000, preferably 30 to 200,000.
It is 10,000 to 1,800,000, more preferably 400,000 to 1,500,000. If the weight average molecular weight is smaller than 200,000, the HOT of the toner decreases. When the weight average molecular weight exceeds 2,000,000, the MFT of the toner becomes high. The glass transition point of (C) is usually 40 ° C to 80 ° C. The content of (a) in (C) is usually 0.00
It is 1 mEq / g to 0.5 mEq / g. It is preferably from 0.002 mEq / g to 0.4 mEq / g, and more preferably from 0.003 mEq / g to 0.3 mEq / g.
Is more preferred. When (a) is an acid anhydride group, it is preferable to copolymerize a vinyl monomer having a carboxyl group when polymerizing (C) in order to improve charging characteristics. Examples of the vinyl monomer having a carboxyl group include monoesters of unsaturated dibasic acids such as (meth) acrylic acid, maleic acid, fumaric acid, cinnamic acid, and monobutyl maleate. Among these, (meth) acrylic acid and monobutyl maleate are preferred.

As the polymerization method for producing (C), any method such as solution polymerization, bulk polymerization, suspension polymerization and the like can be selected. The polymerization initiator is not particularly limited. For example, azo initiators such as azobisisobutyronitrile and azobisisovaleronitrile; benzoyl peroxide, di-t-butyl peroxide, lauroyl peroxide, dicumyl Peroxide initiators such as peroxides; 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 1,1-bis (t-butylperoxy) 3,3,5- Polyfunctional polymerization initiators having two or more peroxide groups in one molecule such as trimethylcyclohexane and di-t-butylperoxyhexahydroterephthalate; 1 such as diallylperoxydicarbonate and t-butylperoxyallylcarbonate; Multifunctional having one or more peroxide groups and one or more polymerizable unsaturated groups in the molecule Such as polymerization initiators, and the like. Of these, preferred are polyfunctional polymerization initiators.

The solvent used when (C) is obtained by solution polymerization is not particularly limited, but toluene, xylene,
Aromatic solvents such as ethylbenzene, ester solvents such as ethyl acetate and butyl acetate, dimethylformamide,
Dimethyl sulfoxide, methyl ethyl ketone and the like can be mentioned. Preferred are dimethylformamide, xylene and toluene. When (C) is obtained by suspension polymerization, polymerization can be carried out in water using an inorganic salt-based dispersant such as calcium carbonate or calcium phosphate, or an organic dispersant such as polyvinyl alcohol or methylated cellulose. The polymerization temperature is usually 50 to 160 ° C., preferably 60
~ 140 ° C. The polymerization is preferably performed in the presence of an inert gas such as nitrogen.

The low molecular weight compound (D) has a weight average molecular weight of 30.
00 to 50000, preferably 3500 to 400
00, more preferably 4,000 to 30,000. If the weight average molecular weight is smaller than 3000, the heat-resistant storage stability of the toner decreases. If the weight average molecular weight exceeds 50,000, the MFT of the toner becomes high. The glass transition point of (D) is usually 40 ° C to 80 ° C. The functional group equivalent (Eq / g) of (a) in (D) is 50% or less of the functional group equivalent of (a) in (C). It is preferably at most 30%, more preferably at most 10%. If it exceeds 50%, the charging characteristics of the toner become poor. HOT also decreases. When (a) is an acid anhydride group, in order to control charging characteristics,
When polymerizing (D), a vinyl monomer having a carboxyl group can be copolymerized. Examples of the vinyl monomer having a carboxyl group include the monomers described above.

As the polymerization method for producing (D), any method such as solution polymerization, bulk polymerization and suspension polymerization can be selected. Of these, solution polymerization is preferred.
When (D) is polymerized by solution polymerization, it can be polymerized by the solution polymerization method described above. The polymerization initiator for polymerizing (D) is not particularly limited, and includes the polymerization initiators described above. Preferred among these are monofunctional initiators.

The weight ratio of the high molecular weight compound (C) to the low molecular weight compound (D) in (A) is usually from 70/30 to 5/95.
Preferably it is 60/40 to 10/90. More preferably, it is 50/50 to 20/80. The glass transition point (Tg) of (A) is usually from 40 to 80 ° C, and preferably from 50 to 70 ° C, from the viewpoint of heat-resistant storage stability when formed into a toner and MFT when formed into a toner.

The method for introducing the reactive functional group (b) into the styrene resin or the styrene-acrylic resin (B) of the present invention is the same as the method for introducing (a) into (A) described above. It can be obtained by copolymerizing a vinyl monomer having a reactive functional group (b) and a styrene monomer or a styrene monomer and an acrylic monomer. Examples of the monomer having (b) include the vinyl monomers described above. Of these, preferred is (b)
Is an acid anhydride group, maleic anhydride and itaconic anhydride. When (b) is a hydroxyl group, it is 2-hydroxy (meth) acrylate. When (b) is a glycidyl group, it is glycidyl (meth) acrylate. When (b) is an isocyanate group, it is m-isopropenyl-α, α-dimethylbenzyl isocyanate. When (b) is a carboxyl group, it is (meth) acrylic acid or monobutyl maleate. When (b) is an amino group, it is an amino group-containing (meth) acrylate. The monomer to be copolymerized with the monomer having (b) is a styrene-based monomer described above,
Acrylic monomers, other vinyl monomers, and the like are included. Of these, alkyl (meth) acrylates having an alkyl group having 1 to 18 carbon atoms, such as styrene, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate, are preferred. ) Acrylate.

As the polymerization method for producing (B), any method such as solution polymerization, bulk polymerization and suspension polymerization can be selected. Of these, solution polymerization is preferred.
When (B) is polymerized by solution polymerization, it can be polymerized by the solution polymerization method described above. The polymerization initiator for polymerizing (B) is not particularly limited, and examples thereof include the polymerization initiators described above.

The weight average molecular weight of (B) used in the present invention is usually 3000 to 2,000,000, preferably 4000 to 2,000,000.
1,000,000, and more preferably 5000 to 500,000. The glass transition point of (B) is usually from 30 ° C to 150 ° C, preferably from 35 ° C to 90 ° C, more preferably from 40 ° C to 80 ° C. The content of (b) in (B) is usually 0.001 mEq / g to 2 mEq / g. Preferably it is 0.01 mEq / g-1.5 mEq / g. MF
From the viewpoint of the balance between T and HOT, 0.1 mEq / g to 1.mEq / g.
0 mEq / g is more preferred.

The method for producing the resin for toner according to the present invention comprises the steps of (A)
And (B) are blended and obtained by heating. Although (A) and (B) can be heated in the reaction vessel, it is preferable to react (A) and (B) in a heated and molten state using a kneader or the like in order to increase the viscosity. Further, when (A) and (B) are blended as a powder to prepare a toner, the toner can be heated and reacted. The weight ratio of (A) to (B) is usually from 0.2 part to 20 parts for (B) to 100 parts of (A). Preferably (B) is from 0.3 to 15 parts, more preferably from 0.5 to 10 parts.

An example of a method for producing an electrophotographic toner which is used for the toner binder of the present invention is as follows. The toner binder is usually 45 to 95% by weight based on the weight of the toner, and a known coloring agent (carbon black, iron black, Benzidine yellow, quinacdrine, rhodamine B, phthalocyanine, etc.)
Is usually used in a proportion of 5 to 10% by weight and magnetic powder (compounds of iron, cobalt, nickel, hematite, ferrite, etc.) is usually used in a proportion of 0 to 50% by weight, and various additives [charge adjusting agent (metal complex, nigrosine, nigrosine) are used. ), Lubricants (such as polytetrafluoroethylene, low molecular weight polyolefins, fatty acids, or metal salts or amides thereof) and the like]. The amount of these additives is usually 0 to 10% by weight based on the weight of the toner. The electrophotographic toner is dry-blended with the above components, melt-kneaded, coarsely pulverized, and finally finely pulverized using a jet pulverizer or the like to obtain fine particles having a particle size of 5 to 20 μm. The electrophotographic toner, if necessary, iron powder, glass beads,
It is used as a developer for an electric latent image by being mixed with carrier particles such as nickel powder and ferrite. Further, hydrophobic colloidal silica fine powder can be used to improve the fluidity of the powder. The electrophotographic toner includes a support (paper,
It is fixed on a polyester film and used. The fixing method is as described above.

[0020]

The present invention will be further described with reference to the following examples, but the present invention is not limited to these examples. Hereinafter, "part" indicates "part by weight". The methods for measuring the properties of the resins obtained in Synthesis Examples, Examples and Comparative Examples are described below.

Molecular weight measurement apparatus: HLC-802A manufactured by Tosoh Corporation Conditions: column TSK gel GMHXL 2 columns manufactured by Tosoh Corporation Measurement temperature: 40 ° C. Sample solution: 0.25 wt% tetrahydrofuran solution Solution injection amount: 100 μl Detector: Refraction Rate detector The molecular weight calibration curve was created using standard polystyrene.

Glass transition point (Tg) measurement device: DSC20, SS manufactured by Seiko Denshi Kogyo KK
C / 580 Condition: ASTM (D3418-2) method

Preparation of Resin (C) Production Example 1 756.2 parts of styrene, 234 parts of n-butyl acrylate, 3.3 parts of maleic anhydride were placed in an autoclave reactor equipped with a thermometer, a stirrer and a nitrogen inlet tube. , A mixed monomer of 0.15 part of divinylbenzene and 2,2-
After 0.5 part of bis (4,4-di-t-butylperoxycyclohexyl) propane was added, and polymerization was carried out at 90 ° C. for 5 hours in a nitrogen stream, 245 parts of xylene and 3.3 parts of maleic anhydride were added. After polymerization for 1 hour at 90 ° C.,
Polymerization was carried out at 1 ° C. for 1 hour. Further, 2,2-bis (4,4-di-
t-butylperoxycyclohexyl) propane 0.1
Parts, 122 parts of xylene and 3.2 parts of maleic anhydride were charged and polymerized at 110 ° C. for 4 hours, and then 1 part of di-tert-butyl peroxide and 25 parts of xylene were charged at 150 ° C. and polymerized for 2 hours to conduct polymerization. The reaction was completed and the solvent was removed under reduced pressure to obtain a resin (C1). The weight average molecular weight by GPC of (C1) was 600,000, the glass transition point was 60 ° C., and the acid value was 5.6.

Production Example 2 751.2 parts of styrene and n-acrylic acid
Resin (C2) was obtained in the same manner as in Production Example 1, except that 234 parts of butyl, 3.3 parts of maleic anhydride, 5 parts of acrylic acid, and 0.15 part of divinylbenzene were used. GPC of (C2)
Has a weight average molecular weight of 500,000 and a glass transition point of 61
° C, the acid value was 9.5.

Production Example 3 A mixed monomer of 753 parts of styrene, 234 parts of n-butyl acrylate, 13 parts of 2-hydroxyethyl methacrylate and 0.15 part of divinylbenzene was placed in the same reaction vessel as in Production Example 1, and as an initiator, 2,2-bis (4,4-di-t
-Butylperoxycyclohexyl) propane (0.5 part), polymerization in a nitrogen stream at 90 ° C. for 5 hours, xylene (245 parts), polymerization at 90 ° C. for 1 hour, polymerization at 110 ° C. for 1 hour did. Furthermore, 2,2-bis (4,4
-Di-t-butylperoxycyclohexyl) propane (0.1 part) and xylene (122 parts) were charged and polymerized at 110 ° C. for 4 hours. Then, di-t-butyl peroxide (1 part) and xylene (25 parts) were charged at 150 ° C. Polymerization was completed for 2 hours to complete the polymerization, and the solvent was removed under reduced pressure to obtain a resin (C3). The weight average molecular weight by GPC of (C3) is 60.
The glass transition point was 60 ° C. and the hydroxyl value was 5.6.

Production Example 4 The mixed monomer was composed of 750.3 parts of styrene and n acrylic acid.
Resin (C4) was obtained in the same manner as in Production Example 3, except that 234 parts of -butyl, 15.7 parts of 2- (dimethylamino) ethyl methacrylate, and 0.15 part of divinylbenzene were used.
The weight average molecular weight by GPC of (C4) was 500,000, the glass transition point was 59 ° C., and the amine value was 5.5.

Production Example 5 758.8 parts of styrene, n-acrylic acid
Resin (C5) was obtained in the same manner as in Production Example 3 except that 234 parts of butyl, 7.2 parts of acrylic acid, and 0.15 part of divinylbenzene were used. The weight average molecular weight by GPC of (C5) was 550,000, the glass transition point was 60 ° C., and the acid value was 5.5.

Preparation of Resin (D) Production Example 6 452 parts of xylene was placed in the same apparatus as in Production Example 1, and after replacing with nitrogen, a mixed monomer of 845 parts of styrene and 155 parts of n-butyl acrylate was added at 170 ° C. and an initiator. As di-t-
A mixture of 6.4 parts of butyl peroxide and 125 parts of xylene was added dropwise over 3 hours. After dropping, the mixture was aged at 170 ° C. for 1 hour to complete the polymerization. Thereafter, the solvent was removed under reduced pressure to obtain a resin (D1). The weight average molecular weight by GPC of (D1) was 13,000, and the glass transition point was 59 ° C.
Met.

Production Example 7 839.9 parts of styrene mixed with n-acrylic acid
Resin (D2) was obtained in the same manner as in Production Example 6 except that 155 parts of butyl and 5.1 parts of acrylic acid were used. GP of (D2)
The weight average molecular weight by C is 12,000 and the glass transition point is 6
At 0 ° C., the acid value was 4.0.

Production Example 8 839.9 parts of styrene mixed with n-acrylic acid
Resin (D3) was prepared in the same manner as in Production Example 6 except that 155 parts of butyl and 10 parts of 2-hydroxyethyl methacrylate were used.
I got The weight average molecular weight by GPC of (D3) was 1.
30,000, the glass transition point was 60 ° C., and the hydroxyl value was 4.3.

Production Example 9 200 parts of xylene was placed in the same apparatus as in Production Example 1, and after replacing with nitrogen, at 140 ° C., a mixed monomer of 800 parts of styrene and 200 parts of n-butyl acrylate was mixed with di-t-t-butyl as an initiator.
A mixture of 4.9 parts of butyl peroxide and 100 parts of xylene was added dropwise over 3 hours. After dropping, the mixture was aged at 145 ° C. for 1 hour to complete the polymerization. Thereafter, the solvent was removed under reduced pressure to obtain a resin (D4). The weight average molecular weight by GPC of (D4) was 60,000, and the glass transition point was 60 ° C.

Preparation of Resin B Preparation Example 10 The mixed monomer was 803 parts of styrene, 145 parts of n-butyl acrylate, and 52 parts of 2-hydroxyethyl methacrylate.
A resin (B1) was obtained in the same manner as in Production Example 6 except that the above-mentioned parts were used. The weight average molecular weight by GPC of (B1) is 1.3.
The glass transition point was 54 ° C. and the hydroxyl value was 22.5.

Production Example 11 792.2 parts of styrene mixed with n-acrylic acid
145 parts of butyl and 62.8 parts of 2- (dimethylamino) ethyl methacrylate were prepared in the same manner as in Production Example 6,
Resin (B2) was obtained. The weight average molecular weight by GPC of (B2) was 1,000,000, the glass transition point was 56 ° C, and the amine value was 22.4.

Production Example 12 815.8 parts of styrene and n-acrylic acid
Resin (B3) was obtained in the same manner as in Production Example 6, except that 145 parts of butyl and 39.2 parts of maleic anhydride were used. (B3)
Has a weight average molecular weight of 9000, a glass transition point of 53 ° C. and an acid value of 23 by GPC.

Production Example 13 Resin (B4) was prepared in the same manner as in Production Example 6 except that 768 parts of styrene, 145 parts of n-butyl acrylate, and 87 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate were used. I got The weight average molecular weight by GPC of (B4) was 12,000, the glass transition point was 55 ° C., and the isocyanate group content was 0.4 mmeq / g.

Preparation of Resin (A) Production Examples 14 to 20 100 parts of xylene was charged into a cooling pipe and a kolben equipped with a stirrer, and the amount of (D) shown in Table 1 was added and dissolved.
(C), and after nitrogen replacement, stirring at 150 ° C. for 2 hours.
Stir for an hour to dissolve uniformly. Thereafter, the solvent was removed under reduced pressure at 170 ° C. to obtain resins (A1) to (A7). Table 1 shows (A)
Is shown.

[0037]

[Table 1] -------------------------- Resin (C) (D) Tg ° C --------- −−−−−−−−−−−−−−−−−−−−−−−−−−− 14 A1 C1 40 parts D1 60 parts 59 15 A2 C2 40 parts D2 60 parts 60 16 A3 C3 40 parts D1 60 parts 59 Structure 17 A4 C4 40 parts D1 60 parts 59 18 A5 C5 40 parts D1 60 parts 59 Example 19 A6 C3 40 parts D3 60 parts 60 20 A7 C1 40 parts D4 60 parts 60 −−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−

Examples 1 to 7 Resin (A) obtained in Production Examples 14 to 17 and Production Example 10
The resin (B) obtained in Step 13 was powder-blended at the compounding ratio shown in Table 2, melt-kneaded in a twin-screw extruder at an internal temperature of 210 ° C., and reacted with (A) and (B) to produce the toner of the present invention. Binders (TB1) to (TB7) were obtained.

[0039]

[Table 2] -------------------- Resin (A) (B) --------- −−−−−−−−−−−−−−−−−−−−− 1 TB1 A1 100 B1 6.3 Actual 2 TB2 A1 100 B2 6.3 3 TB3 A2 100 B1 6.3 Application 4 TB4 A2 100 parts B2 6.3 parts 5 TB5 A3 100 parts B3 6.3 parts Example 6 TB6 A4 100 parts B3 6.3 parts 7 TB7 A4 100 parts B4 6.3 parts −−−−−−−−−−−−−−−−−−−−−− −−−−−−−−−−−−

Comparative Examples 1 to 6 Comparative toner binders (TB8 to TB11) were obtained by using the components shown in Table 3 in the same manner as in Example 1.

[0041]

[Table 3] ------------------------------------------ Resin (A) (B) -------------- −−−−−−−−−−−−−−−−−−−−−− Ratio 1 TB8 A5 100 parts B1 6.3 parts 2 TB9 A6 100 parts B3 6.3 parts Example 3 TB10 A7 100 parts B1 6.3 parts 4 TB11 A1 100 parts None −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Use Examples and Comparative Use Examples The evaluation of the toner binder was performed in two ways: a two-component development system and a one-component development system. Evaluation of Two-Component Development Method In each of 88 parts of the toner binder of the present invention in Examples 1 to 7 and the toner binder of Comparative Examples 1 to 4, 7 parts of carbon black (MA100 manufactured by Mitsubishi Kasei Co., Ltd.) and low molecular weight polypropylene (Sanyo) Viscole 5 manufactured by Kasei Kogyo Co., Ltd.
After uniformly mixing 3 parts of 50P) and 2 parts of a charge controlling agent (Spiron Black TRH manufactured by Hodogaya Chemical Industry Co., Ltd.), the mixture was kneaded with a twin-screw extruder at an internal temperature of 150 ° C, and the cooled product was finely pulverized with a jet mill. The resulting mixture was classified by a dispersion separator to obtain toners a to k having an average particle diameter of 12 μm.

Test Example 1 To 3 parts of each of the toners a to k, 97 parts of a ferrite carrier (F-100 manufactured by Powdertech Co., Ltd.) were mixed uniformly,
A toner image is transferred onto paper using a commercially available copying machine (BD-7720, manufactured by Toshiba Corporation), and the transferred toner is remodeled into a fixing unit of a commercially available copying machine (SF8400A, manufactured by Sharp Corporation). The fixing test was performed at a speed of 35 sheets of A4 paper per minute. The image quality was determined based on the image density after fixing. The test results are as shown in Table 4.

Test Example 2 Each of the toners a to k was placed in a polyethylene bottle,
After being kept in a constant temperature water bath at 45 ° C. for 8 hours, the mixture was transferred to a 42-mesh sieve and shaken for 10 seconds using a powder tester manufactured by Hosokawa Micron Corp., and the weight% of the toner remaining on the sieve was measured. Sex test.
The smaller the number, the better the heat-resistant storage stability. If it is less than 35%, it can be used without any problem. Table 4 shows the results.

[0045]

Table 4 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Toner Toner MFT HOT Image resistance Heat resistance Heater interface (° C) (° C) Storage * 1 * 2 * 3 (%) −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Actual a TB1 128> 240 〇 27 b TB2 128> 240 〇 27 Application c TB3 127> 240 ◎ 28 d TB4 128> 240 ◎ 29 Example e TB5 130 235 ○ 28 f TB6 130 240 ○ 27 g TB7 131 235 ○ 27 −−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−− h TB8 132 190 ○ 28 ratio i TB9 132 195 ○ 29 comparison j TB10 144> 240 ◎ 30 Example k TB11 140 185 ○ 27 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− * 1 Solid black part with an image density of 1.2 Rubbing with a reciprocating number of 5 times using a degree tester (friction part = paper), and the image density of the solid part after friction remains at 70% or more. Heat roll temperature at which to obtain a copy that was. * 2 Heat roll temperature when toner is hot offset * 3 ３: Image density (I.D)> 1.4, ：: (I.D) 1.0 to 1.4, Δ: (I.D) <1.0

In the evaluation by the two-component developing system, the toners a to g using the binder of the present invention all have higher heat storage stability than the toners h to k using the comparative binder.
Excellent balance between low-temperature fixability and hot offset resistance without impairing image quality.

Evaluation of one-component developing system Magnetic powder (EPT-1000, manufactured by Toda Kogyo KK) was added to 48.8 parts of each of the toner binder of the present invention of Examples 1 to 7 and the toner binder of Comparative Examples 1 to 48. .8 copies,
After uniformly mixing 2 parts of low molecular weight polypropylene (Himer TP-32 manufactured by Sanyo Chemical Industry Co., Ltd.) and 0.4 part of charge control agent (T-77 manufactured by Hodogaya Chemical Industry Co., Ltd.),
The mixture was kneaded with a twin-screw extruder at an internal temperature of 130 ° C., and the cooled product was finely pulverized with a jet mill and classified with a dispersion separator to obtain toners A to K having an average particle size of 8 μm.

Test Example 3 Toners A to K were transferred to a toner image on paper using a commercially available laser beam printer (manufactured by Canon Inc., LBP-210), and the transferred toner on paper was compared to Test Example 1 described above. A fixing test and evaluation of image quality were performed in the same manner. The test results are as shown in Table 5.

Test Example 4 Toners A to K were tested for heat resistance in the same manner as in Test Example 2. If it is less than 35%, it can be used without any problem. Table 5 shows the results.

[0050]

Table 5-----------------------------------Toner Toner MFT HOT Image resistance Storage property * 1 * 2 * 3 (%) ---------------------------------------------------- Real A TB1 130> 240 ○ 28 B TB2 130> 240 ○ 27 Application C TB3 128> 240 ◎ 29 D TB4 128> 240 ◎ 28 Example E TB5 131 235 ○ 28 F TB6 132 240 ○ 28 G TB7 132 230 ○ 27 −−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−− H TB8 133 190 ○ 28 ratio I TB9 133 190 ○ 29 comparison J TB10 148> 240 ◎ 30 Example K TB11 143 180 ○ 27 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− * 1 Solid black part with an image density of 1.2 With a reciprocating frequency of 2 times with a degree tester (friction part = paper), and the image density of the solid part after friction remains at 70% or more. Heat roll temperature at which to obtain a copy that was. * 2 Heat roll temperature when toner is hot offset * 3 ３: Image density (I.D)> 1.4, ：: (I.D) 1.0 to 1.4, Δ: (I.D) <1.0

In the evaluation by the one-component developing method, all of the toners A to G using the binder of the present invention have higher heat storage stability than the toners HK using the comparative binder.
Excellent balance between low-temperature fixability and hot offset resistance without impairing image quality.

[0052]

As described above, the toner binder of the present invention introduces a specific reactive functional group (a) into a polymer portion,
By reacting with a resin having a functional group (b) that reacts with (a), heat-resistant storage stability and low-temperature fixability are maintained,
A toner having excellent hot offset resistance can be obtained.

Claims (7)

(57) [Claims] 1. Styrene having a reactive functional group (a)
Functional group (b) that reacts with acrylic resin (A) and (a)
In a toner binder for electrophotography comprising a styrene-based resin or a styrene-acrylic resin (B) having (A), (A) is a polymer having a weight-average molecular weight of 200,000 to 2,000,000 and (C) a polymer having a weight-average molecular weight of 200 to 2,000,000. 3000-500
(D), wherein the equivalent (a) of (a) in (D) is 50 equivalents of the equivalent of (a) in (C).
% Or less, wherein (a) is a reactive functional group selected from the group consisting of an acid anhydride group, a hydroxyl group, an isocyanate group, an amino group and a glycidyl group. 2. The binder according to claim 1, wherein (a) in (A) and at least a part of (b) in (B) react. 3. The binder according to claim 1, wherein (a) is an acid anhydride group, and (b) is a functional group selected from the group consisting of a hydroxyl group, an amino group and an isocyanate group. 4. The binder according to claim 1, wherein (a) is a hydroxyl group, and (b) is a functional group selected from the group consisting of an acid anhydride group, an isocyanate group and a glycidyl group. 5. The binder according to claim 1, wherein (a) is an amino group, and (b) is a functional group selected from the group consisting of an acid anhydride and an isocyanate group. 6. The binder according to claim 1, wherein (a) is an isocyanate group, and (b) is a functional group selected from the group consisting of a hydroxyl group, an amino group, a carboxyl group, an acid anhydride group, and a glycidyl group. . 7. The binder according to claim 1, wherein (a) is a glycidyl group, and (b) is a functional group selected from the group consisting of an acid anhydride group and a carboxyl group.