JP2012032450A - Electrophotographic toner binder and toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner binder which, when used to prepare a toner, can provide high levels of low-temperature fixability and hot offset resistance, and ensures excellent image stability in long-time use.SOLUTION: The electrophotographic toner binder comprises a styrene (co)polymer (A), which comprises a styrene (co)polymer (a) having a molecular weight distribution maximum value of 2,500 or more and 5,000 or less, a styrene (co)polymer (b) having a molecular weight distribution maximum value of more than 5,000 and 200,000 or less, and a styrene (co)polymer (c) having a molecular weight distribution maximum value of more than 200,000 and 1,000,000 or less in a weight ratio (a):(b):(c) of (30-44):(5-45):(12-45), and a hydrocarbon wax (F) having a melting point of 65°C-105°C in a weight ratio (A):(F) of (92-98):(8-2).

Description

  The present invention relates to a toner used for electrophotography, electrostatic recording, electrostatic printing, and the like, and an electrophotographic toner binder used therefor.

In electrophotography, a contact heating fixing method such as a heat roller is widely adopted as a method for fixing an electrostatic latent image visualized with toner.
When this method is used, the minimum toner fixing temperature (the minimum temperature of the heat roller that can obtain a fixing rate of 70%) is low (low temperature fixing property), and the hot offset temperature (the minimum temperature of the heat roller that generates hot offset) is low. High (hot offset resistance) is desired. In addition, it is desired that a clear image can be obtained even when used for a long time (image stability). In order to satisfy these demands, it has been proposed that the molecular weight distribution of the toner binder ranges widely from a low molecular weight to a high molecular weight, and that the order of the glass transition points of the constituent components is defined (see Patent Document 1). A method of adding a low melting point wax has also been proposed (see Patent Document 2).

JP-A-9-297432 JP 2007-47636 A

  However, even if the molecular weight distribution is widened or the order of the glass transition point is specified, sufficient low-temperature fixability cannot be obtained, and only a low melting point wax is added to a resin composed of a low molecular weight polymer and a high molecular weight polymer. However, sufficient image stability cannot be obtained.

As a result of intensive studies to solve the above problems, the present inventors have reached the present invention.
That is, the present invention relates to a styrene (co) polymer (a) having a molecular weight distribution maximum value of 2500 or more and 5000 or less, a styrene (co) polymer (b) having a molecular weight distribution maximum value of more than 5000 and 200,000 or less, and a molecular weight distribution. It contains a styrene (co) polymer (c) having a maximum value of more than 200,000 and not more than 1,000,000, and the respective weight ratios are (a) :( b) :( c) = (30-44) :( 5 45): A styrene (co) polymer (A) which is (12 to 45) and a hydrocarbon wax (F) having a melting point of 65 ° C. to 105 ° C., and a weight ratio of (A) to (F) (92 to 98): (8 to 2) an electrophotographic toner binder; and a toner containing the electrophotographic toner binder and a colorant.

  The toner binder for electrophotography of the present invention is an excellent toner that has a low temperature fixing property and a hot offset resistance as a toner performance, and has no trouble in image stability when used for a long time. Obtainable.

The present invention is described in detail below.
The toner binder for electrophotography of the present invention contains a styrene (co) polymer (A) and a hydrocarbon wax (F) having a melting point of 65 ° C. to 105 ° C.
The weight ratio of (A) to (F) (the sum of (A) and (F) is 100) is (92 to 98) :( 8 to 2), preferably (93 to 97) :( 7-3). The weight ratio of the hydrocarbon wax (F) having a melting point of 65 ° C. to 105 ° C. needs to be 2 or more from the viewpoint of low-temperature fixability, and needs to be 8 or less from the viewpoint of image stability.

The styrene (co) polymer (A) is a styrene (co) polymer (a), a styrene (co) polymer (b), and a styrene (co) polymer (c) having different molecular weight distribution maximum values. contains.
As a monomer which comprises styrene (co) polymer (a), (b), and (c), a styrene monomer is made into an essential monomer, and a (meth) acryl monomer and a carboxyl group-containing vinyl monomer are contained if necessary. Here, the (co) polymer means a homopolymer or a copolymer, and the styrene (co) polymer means a homopolymer of a styrene monomer or a copolymer of a styrene monomer and another monomer. To do. Moreover, (meth) acryl means acryl and / or methacryl, and the same description method is used hereafter.

  Examples of the styrene monomer include styrene, alkyl styrene having an alkyl group having 1 to 3 carbon atoms (for example, α-methyl styrene, p-methyl styrene), and the like. Styrene is preferred.

Examples of (meth) acrylic monomers include alkyl groups such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate. Alkyl (meth) acrylate having 1 to 18 carbon atoms; Hydroxylalkyl (meth) acrylate having 1 to 18 carbon atoms of an alkyl group such as hydroxylethyl (meth) acrylate; Dimethylaminoethyl (meth) acrylate, Diethylaminoethyl (meth) Examples thereof include alkylamino group-containing (meth) acrylates having 1 to 18 carbon atoms in the alkyl group such as acrylate; nitrile group-containing vinyl monomers such as acrylonitrile and methacrylonitrile.
Of these (meth) acrylic monomers, alkyl (meth) acrylates having 1 to 18 carbon atoms, acrylonitrile, methacrylonitrile, and mixtures of two or more thereof are preferable.

Examples of the carboxyl group-containing vinyl monomer include monocarboxylic acids [having 3 to 15 carbon atoms such as (meth) acrylic acid, crotonic acid and cinnamic acid], dicarboxylic acids [having 4 to 15 carbon atoms such as (anhydrous) maleic acid and fumaric acid. , Itaconic acid, citraconic acid], dicarboxylic acid monoester [monoalkyl (carbon number 1 to 18) ester of the above dicarboxylic acid, such as maleic acid monoalkyl ester, fumaric acid monoalkyl ester, itaconic acid monoalkyl ester, citraconic acid monoester Alkyl ester] and the like.
Among these carboxyl group-containing vinyl monomers, (meth) acrylic acid, dicarboxylic acid monoester, and a mixture of two or more thereof are preferable.

If necessary, the styrene (co) polymers (a), (b), and (c) may be used in combination with other vinyl ester monomers and aliphatic hydrocarbon vinyl monomers.
Examples of vinyl ester monomers include aliphatic vinyl esters (4 to 15 carbon atoms such as vinyl acetate, vinyl propionate, isopropenyl acetate, etc.), unsaturated carboxylic acid polyvalent (2 to 3 or more) alcohol esters [carbon number. 8-200, such as ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,6 hexanediol diacrylate, and polyethylene glycol Di (meth) acrylate, etc.], aromatic vinyl esters (carbon number 9-15, such as methyl-4-vinylbenzoate) and the like.
Examples of the aliphatic hydrocarbon vinyl monomer include olefins (having 2 to 10 carbon atoms, such as ethylene, propylene, butene, and octene), dienes (having 4 to 10 carbon atoms, such as butadiene, isoprene, 1,6-hexadiene, and the like). It is done.
The content of other monomers in all the constituent monomers is preferably 15% or less, more preferably 0.001 to 5%.
In the above and the following, “%” means “% by weight” unless otherwise specified.

The acid value of the styrene (co) polymer (A) is preferably 0.2 to 12, more preferably 0.5 to 10, particularly preferably 1 to 9, from the viewpoint of image density. From the viewpoint of image stability, the acid values of the styrene copolymers (a), (b), and (c) are in a relationship of (b)> (a) and (b)> (c). To preferred. In the case of using two or more kinds of (co) polymers in the styrene (co) polymers (a), (b), and / or (c), a weighted average of the acid value and the use ratio of each polymer is used. By doing so, the acid value as (a), (b), and (c) can be calculated.
In the above and below, the acid value is measured by the method defined in JIS K0070 (potentiometric titration method).

The molecular weights of the styrene copolymers (a), (b), (c), and (A) used in the present invention are measured by gel permeation chromatography (GPC).
The maximum molecular weight distribution (a) is usually from 2500 to 5000, preferably from 2600 to 4900, more preferably from 2700 to 4800, from the viewpoint of low-temperature fixability.
The molecular weight distribution maximum of (b) is usually larger than 5000 and 200,000 or less, preferably 10,000 to 180,000, more preferably 1.6 from the viewpoint of improving image stability and improving dispersibility of the colorant. 10,000 to 150,000.
The maximum molecular weight distribution (c) is usually greater than 200,000 and less than or equal to 1 million, preferably 300,000 to 950,000, and more preferably 400,000 to 900,000 from the viewpoint of improving hot offset resistance.
The weight average molecular weight of the styrene (co) polymer (A) is preferably 100,000 to 400,000, more preferably 120,000 to 360,000 from the viewpoint of balancing low-temperature fixability, image stability, and hot offset resistance. Especially preferably, it is 150,000 to 320,000.
Further, the ratio (Mw / Mn) of the weight average molecular weight Mw and the number average molecular weight Mn in (A) is preferably 15 to 150, more preferably 20 to 120, from the viewpoints of the fixing temperature range and image stability.

Above and below, the molecular weight of the resin is measured under the following conditions using GPC.
Device (example): Tosoh HLC-8220
Column (example): TSKgel SuperMultipore HZ-M 3 pieces (manufactured by Tosoh Corporation)
Measurement temperature: 40 ° C
Sample solution: 0.25% THF solution Injection volume: 10 μl
Detector: Refractive index detector Standard material: TOSANDO standard polystyrene (TSK standard POLY STYRENE) 12 points (molecular weight 500 1050 2800 5970 9100 18100 37900 96400
190000 355000 1090000 2890000)
The molecular weight showing the maximum peak height on the obtained chromatogram is defined as the maximum molecular weight distribution.

From the viewpoint of low temperature fixability and storage stability, the glass transition point of the styrene copolymer (A) is preferably 50 to 70 ° C, more preferably 51 to 68 ° C, particularly preferably 52 to 67 ° C, most preferably Preferably it is 53-65 degreeC.
The glass transition point of the styrene (co) polymer (a) is preferably 50 to 65 ° C., more preferably 51 to 64 ° C., and the glass transition point of the styrene copolymers (b) and (c) is preferably Is 50 to 80 ° C, more preferably 53 to 70 ° C.
The glass transition point of the mixture of the hydrocarbon wax (F) having a melting point of 65 ° C. to 105 ° C. and the styrene copolymer (A) in the above weight ratio is the glass transition point of the styrene copolymer (A). It is usually 1-10 ° C. lower than
In the above and below, the glass transition point (Tg) is measured by a method (DSC method) defined in ASTM D3418-82 using DSC20, SSC / 580 manufactured by Seiko Denshi Kogyo Co., Ltd.

Styrene (co) polymers (a), (b), and (c) are known monomers such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization using the radical polymerization initiator (e). It can be synthesized by a polymerization method. Solution polymerization, suspension polymerization and bulk polymerization or a combination thereof are preferred.
The polymerization temperature is preferably 60 to 230 ° C, more preferably 80 to 230 ° C.
The polymerization time is preferably 1 to 30 hours, more preferably 2 to 20 hours.

Examples of (e) include azo polymerization initiators (for example, azobisisobutyronitrile, azobisvaleronitrile, and azobiscyanovaleric acid), and organic peroxide polymerization initiators [for example, benzoyl peroxide, di-t- Butyl peroxide, t-butyl peroxybenzoate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane] and the like.
Of these, di-t-butyl peroxide and 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane are preferred.
The amount of the polymerization initiator used is preferably 0.01 to 10%, more preferably 0.05 to 8%, and particularly preferably 0.1 to 6% based on the total amount of monomers.

Solvents for solution polymerization include cycloalkane solvents having 5 to 12 carbon atoms (such as cyclohexane and methylcyclohexane); aromatic solvents having 6 to 12 carbon atoms (such as benzene, toluene, xylene, ethylbenzene and cumene); ester solvents (Ethyl acetate, butyl acetate, etc.); ether solvents (methyl cellosolve, ethyl cellosolve, butyl cellosolve, etc.) are used.
Of these, preferred are aromatic solvents, and more preferred are toluene, xylene, and ethylbenzene.

  Moreover, when performing suspension polymerization, it can superpose | polymerize in water using inorganic acid salt dispersing agents (calcium carbonate, calcium phosphate, etc.), organic dispersing agents (polyvinyl alcohol, methylcellulose, etc.), etc.

At least one of the styrene (co) polymers (a), (b), and (c) may contain a (co) polymer grafted with a wax (G) described later. In this case, the grafted wax (G) is not included in the weights of (a), (b), and (c) when the weight ratio of (a), (b), and (c) is determined.
The (co) polymer obtained by grafting the wax (G) onto the styrene (co) polymer allows the wax (G) to coexist during the polymerization of the styrene (co) polymers (a) to (c), and is a peroxide type. It can be obtained by polymerization using a polymerization initiator. By using the styrene (co) polymer grafted with the wax (G), the stability of the image is improved. The amount of wax to be used for grafting is preferably 0.01 to 2%, more preferably 0.02 to 1% in the electrophotographic toner binder of the present invention.

Weight ratio of styrene (co) polymers (a), (b), and (c) [ratio to the total weight of (a), (b), and (c). ] Is (a) :( b) :( c) = (30-44) :( 5-45) :( 12-45) from the viewpoint of image stability, preferably (a) :( b) :( c) = (31-43) :( 10-40) :( 15-42).
The ratio of the styrene (co) polymer (a) needs to be 44 or less in order to prevent deterioration of image stability due to the addition of the hydrocarbon wax (F) having a melting point of 65 ° C. to 105 ° C. From the viewpoint of fixability, it should be 30 or more.
In addition, (a), (b), and (c) can be combined with each other as long as the molecular weight distribution maximum value is within a predetermined range. From the viewpoint of image stability, (a), (c) The total number of components of b) and (c) is preferably 3-8, more preferably 4-6.

In addition to the styrene (co) polymers (a), (b), and (c), other resins can be added to the electrophotographic toner binder of the present invention as necessary. Examples of other resins include polyester resins and polyamide resins.
The amount of other resins added is preferably 30% or less, more preferably 20% or less, particularly preferably 10% or less, based on the total amount of (a), (b), and (c).

Examples of the polyester resin include a polycondensate of a polyol and a polycarboxylic acid. In order to seal the terminal carboxylic acid and terminal alcohol, monoalcohol or monocarboxylic acid can be used in combination.
Among the polyols, dihydric alcohols include aliphatic diols having 2 to 20 carbon atoms (ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, etc.), and their alkylene oxide adducts, hydroquinone, catechol. Bisphenol (bisphenol A, bisphenol F, bisphenol AD, etc.) and hydrogenated bisphenol, phenolic glycol obtained by adding alkylene oxide to these, and a mixture of two or more of these. Examples of the alkylene oxide include ethylene oxide and propylene oxide. When a mixture of these alkylene oxides is added, block addition or random addition may be used.
Among these, preferred are ethylene glycol, propylene glycol, neopentyl glycol, 2-3 mol adduct of bisphenol (particularly bisphenol A), and a mixture of two or more of these.
Among the polyols, trihydric or higher alcohols include aliphatic polyhydric alcohols having 3 to 20 carbon atoms (such as sorbitol, pentaerythritol, trimethylolpropaneglycerol), and alkylene oxide adducts thereof.
Among the polycarboxylic acids, examples of the divalent acid include alkyl or alkenyl dicarboxylic acids having 2 to 20 carbon atoms (for example, succinic acid, maleic acid, and adipic acid), and aromatic carboxylic acids having 8 to 20 carbon atoms (for example, terephthalic acid). , Isophthalic acid) and anhydrides and lower alkyl (methyl, ethyl) esters of these acids.
Among the polycarboxylic acids, trivalent or higher valent acids include aliphatic polycarboxylic acids having 7 to 20 carbon atoms, aromatic polycarboxylic acids having 9 to 20 carbon atoms (1,2,4 benzenetricarboxylic acid, pyromellitic acid, etc. ), And anhydrides and lower alkyl (methyl, butyl, etc.) esters thereof.

Examples of polyamide resins include lactam ring-opening polymers, aminocarboxylic acid polycondensates, and polycondensates of the above polycarboxylic acids and polyamines.
Examples of the lactam include lactams having 6 to 12 carbon atoms such as caprolactam, enantolactam, laurolactam, and undecanolactam.
Examples of aminocarboxylic acids include aminocarboxylic acids having 2 to 12 carbon atoms such as amino acids (glycine, alanine, valine, leucine, isoleucine, and phenylalanine), ω-aminocaproic acid, ω-aminoenanthic acid, ω-aminocaprylic acid. , Ω-aminopelargonic acid, ω-aminocapric acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.
The ring-opening polymerization and polycondensation reaction can be performed by a conventional method using a known catalyst or the like.

The toner binder for electrophotography of the present invention contains a hydrocarbon wax (F) having a melting point of 65 ° C. to 105 ° C. in order to improve low temperature fixability.
The melting point of the wax is measured according to JIS K7122 using RDC-220 manufactured by Seiko Denshi Kogyo, and the maximum temperature of the maximum endothermic peak is defined as the melting point.
Examples of the hydrocarbon wax (F) having a melting point of 65 ° C. to 105 ° C. include paraffin wax, microcrystalline wax, Fischer-Tropsch wax, and low molecular weight polyethylene. The melting point of (F) is preferably 67 ° C to 102 ° C.
The content of the hydrocarbon wax (F) having a melting point of 65 ° C. to 105 ° C. in the electrophotographic toner binder of the present invention is preferably 2 to 8%, more preferably 3 to 6%.

  The electrophotographic toner binder of the present invention may contain a polyolefin wax (G) other than the hydrocarbon wax (F) having a melting point of 65 ° C. to 105 ° C. in order to further improve the offset resistance.

  Examples of the polyolefin wax (G) include olefin (co) polymer (G-1), olefin (co) polymer oxide (G-2), and olefin (co) polymer male modified product (G). -3), a copolymer (G-4) of an olefin and an unsaturated carboxylic acid and / or an unsaturated carboxylic acid alkyl ester, and the like.

(G-1) includes (co) polymers such as ethylene, propylene, 1-butene, isobutylene, 1-hexene, 1-dodecene, 1-octadecene, and mixtures thereof (for example, polyethylene, polypropylene, ethylene / propylene). Copolymer, ethylene / 1-butene copolymer, and propylene / 1-hexene copolymer).
(G-1) includes those obtained by (co) polymerization of olefins (G-1-1) and heat-reduced polyolefins (G-1-2).

  Examples of (G-1-2) include polyolefins obtained by thermally degrading polyolefin resins (for example, polyethylene and polypropylene) having a weight average molecular weight (Mw) of 50,000 to 5,000,000.

Examples of (G-2) include the oxides of (G-1) above.
The oxidation can be performed by a known method using oxygen and / or ozone, for example, by the method described in US Pat. No. 3,692,877.

(G-3) includes maleic acid monomers of the above (G-1) [maleic acid and its derivatives (maleic anhydride; monomethyl maleate, monobutyl maleate, dimethyl maleate, etc., carbon number of maleic acid] 1-4 mono- or dialkyl ester)] modified products and the like.
The modification can be performed by a known method, for example, by reacting (G-1) and a maleic acid monomer by a solution method or a melting method using a known peroxide catalyst. be able to.

(G-4) includes the olefin and unsaturated carboxylic acid [(meth) acrylic acid, itaconic acid, maleic anhydride, etc.] and / or unsaturated carboxylic acid alkyl ester [(meth) acrylic acid alkyl (alkyl carbon And a copolymer with alkyl maleate (alkyl 1 to 18 alkyl ester, etc.)] and the like.
The copolymerization can be performed by a known method using a known catalyst.

The number average molecular weight of the polyolefin wax (G) is preferably 1000 to 30,000, more preferably 1500 to 25000, particularly 2000 to 20,000, from the viewpoint of filming on a carrier and the wax.
The melting point of the polyolefin wax (G) is preferably 110 to 165 ° C, more preferably 120 to 160 ° C, particularly 140 to 155 ° C, from the viewpoint of filming on the carrier and the wax.

  The method for mixing the styrene (co) polymers (a), (b), and (c) is not particularly limited, but a method in which (a), (b), and (c) are separately polymerized and mixed in a solution state, Examples include a method of polymerizing another polymer in the presence of each polymer.

  The mixing method of the styrene (co) polymer (A) and the hydrocarbon wax (F) having a melting point of 65 ° C. to 105 ° C. includes mixing in a solution state and the hydrocarbon wax (F) having a melting point of 65 ° C. to 105 ° C. Examples thereof include a method of polymerizing the (co) polymer constituting the styrene (co) polymer (A) in the presence, and a method of melt-mixing with a twin-screw extruder, a blending pot capable of heating and stirring, and the like.

  The toner of the present invention is composed of the electrophotographic toner binder of the present invention and a colorant, and various additives such as wax, charge control agent and fluidizing agent can be mixed as required.

Known pigments, dyes and magnetic powders can be used as the colorant. Specifically, carbon black, Sudan Black SM, First Yellow-G, Benzidine Yellow, Pigment Yellow, Indian First Orange, Irgasin Red, Paranitroaniline Red, Toluidine Red, Carmine FB, Pigment Orange R, Lake Red 2G, Rhodamine FB, Rhodamine B lake, Methyl violet B lake, Phthalocyanine blue, Pigment blue, Brilliant green, Phthalocyanine green, Oil yellow GG, Kayaset YG, Orazole brown B, Oil pink OP, and magnetic powder [eg, ferromagnetic metal powder (Iron, cobalt, nickel, etc.), magnetite, hematite, and ferrite].
The content of the colorant in the toner of the present invention is preferably 1 to 15%, more preferably 2 to 10% when using a dye or pigment, and preferably 15 when using magnetic powder. -70%, More preferably, it is 30-60%.

Examples of the wax include the same waxes as those described above (F) and (G).
The amount of wax in the toner of the present invention (including the amount of wax contained in the toner binder for electrophotography) is preferably 1 to 10%, more preferably 2 to 8%.

Examples of the charge control agent include metal-containing azo dyes, nigrosine dyes, and quaternary ammonium salt compounds.
The content of the charge control agent in the toner of the present invention is preferably 0 to 5%, more preferably 1 to 5%.

Examples of the fluidizing agent include known materials such as colloidal silica, alumina powder, titanium oxide powder, and calcium carbonate powder.
The content of the fluidizing agent in the toner of the present invention is preferably 0 to 5%.

Examples of the toner production method include a known kneading and pulverizing method. For example, the toner constituents are dry blended using a Henschel mixer or the like, then melt-kneaded at 70 ° C. to 190 ° C. using a twin screw extruder or the like, then coarsely pulverized, and finally a jet pulverizer or the like. Fine particles are used and further classified to obtain particles having a volume average particle diameter (D50) of 5 to 15 microns.
D50 is measured using a Coulter counter [for example, trade name: Multisizer III (manufactured by Beckman Coulter)].
Further, in the above method, the fluidizing agent can be used after being mixed (externally added) after the toner is finely divided.

If necessary, the toner is mixed with carrier particles such as ferrite whose surface is coated with glass beads and / or a resin (acrylic resin, silicone resin, etc.) and used as a developer. Further, instead of the carrier particles, it can be charged by friction with a member such as a charging blade.
Next, the toner is moved to the electrostatic latent image on the photoreceptor, and further moved onto a support (paper, polyester film, etc.).
Furthermore, the recording material is fixed to a support by a known hot roll fixing method or the like.

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Hereinafter, a part shows a weight part.
The toner test method is as follows.

(1) Minimum Fixing Temperature After 30 parts of an evaluation sample (toner) and 800 parts of a ferrite carrier (F-150, manufactured by Powdertech) were uniformly mixed to obtain a two-component developer, it was subjected to the following test.
A fixing unit of a commercially available monochrome copier [SF8400A, manufactured by Sharp Corporation] was remodeled from an unfixed image developed using a commercially available monochrome copier [AR5030, manufactured by Sharp Corporation], and the heat roller temperature was made variable. Fixing was performed at a process speed of 145 mm / sec with a fixing machine. An image having an image density (ID) = 0.6 was rubbed in 5 reciprocations by the Gakushin friction fastness test (rubbing with paper), and the fixing rate (ID after friction 100 × 100 / The heat roller temperature at which ID before friction was 70% or more was defined as the minimum fixing temperature.

(2) Hot offset occurrence temperature Fixing was performed in the same manner as in (1) above, and the presence or absence of hot offset on the fixed image was visually determined. The temperature at which hot offset began to occur was defined as the hot offset occurrence temperature.

(3) Image Stability As in (1) above, continuous copying was performed using a commercially available monochrome copying machine [AR5030, manufactured by Sharp Corporation] as a two-component developer, and the change in image quality was evaluated according to the following criteria.
◎ No change in image quality and no fogging after 10,000 copies.
○ Fogging occurs after 10,000 copies.
Δ: Fog is generated after copying 6,000 sheets.
X: Fog occurs after 2,000 copies.

(4) Storage stability Twenty parts of the evaluation sample (toner) was sealed in a glass bottle, allowed to stand in a constant temperature water bath at 50 ° C. for 8 hours, and then subjected to vibration at a vibration strength of 5 for 10 seconds on a sieve having an opening of 355 μm. From the ratio (weight) of the amount of toner remaining on the screen to the amount placed on the screen, the following criteria were used for evaluation. The apparatus used was a powder tester PT-E manufactured by Hosokawa Micron.
○: Residual toner amount on the screen less than 10% Δ: Residual toner amount on the screen more than 10% to less than 20% ×: Residual toner amount on the screen more than 20%

Production Example 1
After charging 500 parts of xylene in an autoclave and replacing with nitrogen, the temperature was raised to 200 ° C. in a sealed state with stirring. A mixed solution of 1000 parts of styrene, 48 parts of di-t-butyl peroxide and 200 parts of xylene was dropped and polymerized over 3 hours while controlling the temperature in the autoclave at 200 ° C. Further, the polymerization was completed at the same temperature for 1 hour to obtain a polymer solution (a-1).

Production Example 2
The autoclave was charged with 500 parts of xylene and 1 part of low molecular weight polypropylene (Biscol 550P manufactured by Sanyo Chemical Industries, Ltd.) and replaced with nitrogen, and then heated to 185 ° C. in a sealed state with stirring. While controlling the temperature inside the autoclave at 185 ° C., a mixed solution of 966 parts of styrene, 30.5 parts of n-butyl methacrylate, 3.5 parts of methacrylic acid, 30 parts of di-t-butyl peroxide, and 200 parts of xylene, The solution was dropped and polymerized over 3 hours. Further, the polymerization was completed at the same temperature for 1 hour to obtain a polymer solution (a-2).

Production Example 3
The monomer used was 978 parts of styrene, 10 parts of n-butyl acrylate, 12 parts of acrylic acid, 22 parts of di-t-butyl peroxide, and the polymerization temperature was 185 ° C. A combined solution (a-3) was obtained.

Production Example 4
The monomer used is 853 parts of styrene, 130 parts of n-butyl acrylate, 17 parts of acrylic acid, 10 parts of di-t-butyl peroxide, and the polymerization temperature is 160 ° C. A combined solution (b-1) was obtained.

Production Example 5
The monomer used is 780 parts of styrene, 210 parts of n-butyl acrylate, 10 parts of acrylic acid, 4.8 parts of di-t-butyl peroxide, and the same as in Production Example 1 except that the polymerization temperature is 150 ° C. A polymer solution (b-2) was obtained.

Production Example 6
After 200 parts of xylene was charged into an autoclave and replaced with nitrogen, the temperature was raised to 140 ° C. in a sealed state with stirring. A mixed solution of 800 parts of styrene, 200 parts of n-butyl acrylate, 1.4 parts of di-t-butyl peroxide, and 100 parts of xylene was added dropwise over 3 hours while controlling the temperature in the autoclave at 140 ° C. And polymerized. Furthermore, after maintaining at the same temperature for 2 hours, it heated up at 175 degreeC and superposed | polymerized for 1 hour, and the polymer solution (b-3) was obtained.

Production Example 7
A polymer solution (b-4) was obtained in the same manner as in Production Example 6, except that 706.5 parts of styrene, 270 parts of n-butyl acrylate, and 23.5 parts of acrylic acid were used.

Production Example 8
After the autoclave was replaced with nitrogen, 742 parts of styrene, 250 parts of n-butyl acrylate, and 8 parts of acrylic acid were charged, and the temperature was raised to 95 ° C. over 1 hour. Next, 8 parts of 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane was charged, and bulk polymerization was performed at 95 ° C. for 4 hours. Subsequently, 240 parts of xylene was added dropwise over 1 hour, then the temperature was raised to 110 ° C. over 1 hour, and polymerization was performed at the same temperature for 2 hours. Further, 3.2 parts of 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane was charged and polymerized for 4 hours. Thereafter, the temperature was raised to 150 ° C. over 1 hour, and after polymerization at the same temperature for 1 hour, 1400 parts of xylene was added and diluted to obtain a polymer solution (c-1).

Production Example 9
1900 parts of water and 100 parts of a 2% aqueous solution of polyvinyl alcohol [PVA235 manufactured by Kuraray Co., Ltd.] are added to a four-necked flask, and 790 parts of styrene, 210 parts of n-butyl acrylate, 1.2 parts of monobutyl maleate, A mixed solution consisting of 4 parts of 2.2-bis (4,4-di-t-butylperoxycyclohexyl) propane was added and stirred to form a suspension. After sufficiently replacing the flask with nitrogen, the temperature was raised to 95 ° C. to initiate polymerization. Polymerization was continued at the same temperature, and after confirming that the monomer conversion rate was 98% after 24 hours, the temperature was raised to 100 ° C. and kept at the same temperature for 2 hours to complete the polymerization. As a post-treatment, filtration, washing with water and drying were performed to obtain a polymer (c-2).

Production Example 10
A polymer (c-3) was obtained in the same manner as in Production Example 9, except that 750 parts of styrene and 250 parts of n-butyl acrylate were used, and the polymerization temperature up to a monomer conversion rate of 98% was 90 ° C. .

Example 1
In the autoclave, 754 parts of the polymer solution (a-1), 154 parts of the polymer solution (b-1), 260 parts of the polymer solution (b-3), 743 parts of the polymer solution (c-1), 70 parts of Fischer-Tropsch wax having a melting point of 92 ° C. was charged and dissolved uniformly under reflux of xylene. Next, the temperature was raised to 170 ° C. while distilling off xylene, and then the pressure was reduced. Solvent removal was continued at a pressure of 1 kPa or less, and it was confirmed by gas chromatography that the xylene content in the resin was 400 ppm or less to obtain a toner binder (TB-1).

Example 2
The polymer (solution) and hydrocarbon wax used are 692 parts of polymer solution (a-2), 154 parts of polymer solution (b-2), 143 parts of polymer solution (b-4), A toner binder (TB-2) was prepared in the same manner as in Example 1 except that 531 parts of the combined solution (c-1), 200 parts of the polymer (c-3) and 50 parts of paraffin wax having a melting point of 68 ° C. were used. Obtained.

Example 3
The polymer (solution) and hydrocarbon wax used were 569 parts of polymer solution (a-3), 240 parts of polymer solution (b-1), 339 parts of polymer solution (b-4), A toner binder (TB-3) was obtained in the same manner as in Example 1 except that 270 parts of the combined body (c-2) and 40 parts of Fischer-Tropsch wax having a melting point of 78 ° C. were used.

Example 4
The polymer (solution) and hydrocarbon wax used were 754 parts of polymer solution (a-1), 221 parts of polymer solution (b-4), 398 parts of polymer solution (c-1), A toner binder (TB-4) was obtained in the same manner as in Example 1 except that the blend (c-2) was changed to 250 parts and the Fischer-Tropsch wax having a melting point of 78 ° C.

Comparative Example 1
The polymer (solution) and hydrocarbon wax used were 1053 parts of polymer solution (a-1), 195 parts of polymer solution (b-3), 250 parts of polymer (c-3), melting point 68. A comparative toner binder (RTB-1) was obtained in the same manner as in Example 1 except that 50 parts of paraffin wax was used.

Comparative Example 2
The polymer (solution) and hydrocarbon wax used were 638 parts of polymer solution (a-3), 171 parts of polymer solution (b-1), 326 parts of polymer solution (b-4), A comparative toner binder (RTB-2) was obtained in the same manner as in Example 1, except that the blend (c-3) was 280 parts and the Fischer-Tropsch wax having a melting point of 92 ° C. was 10 parts.

Comparative Example 3
The polymer (solution) and hydrocarbon wax used are 727 parts of polymer solution (a-2), 137 parts of polymer solution (b-2), 156 parts of polymer solution (b-4), A comparative toner binder (RTB-3) was prepared in the same manner as in Example 1 except that 531 parts of the combined solution (c-1), 200 parts of the polymer (c-3) and 100 parts of paraffin wax having a melting point of 68 ° C. were used. )

Comparative Example 4
The polymer (solution) and hydrocarbon wax used were 754 parts of polymer solution (a-1), 154 parts of polymer solution (b-1), 260 parts of polymer solution (b-3), A comparative toner binder (RTB-4) was obtained in the same manner as in Example 1 except that the combined solution (c-1) was 743 parts and the melting point was 82 ° C and 70 parts of carnauba wax.

  Table 1 shows the analysis results of the polymer or polymer solution obtained in each of the production examples (the polymer solution is a solid content obtained by removing the solvent) and the toner binder obtained in each of the examples and comparative examples.

[Examples 5-8, Comparative Examples 5-8]
[Create Toner]
To 89 parts of each of toner binders (TB-1) to (TB-4) and (RTB-1) to (RTB-4), 7 parts of carbon black [MA100 manufactured by Mitsubishi Kasei Co., Ltd.], low molecular weight polypropylene [ After two parts of Sanyo Chemical Industries Co., Ltd. Viscol 550P] and 2 parts of a charge control agent (Spiron Black TRH manufactured by Hodogaya Chemical Co., Ltd.) were uniformly mixed with a Henschel mixer FM10B [manufactured by Mitsui Miike Chemical Co., Ltd.], resin Kneaded with a twin screw extruder (PCM30, manufactured by Ikegai Co., Ltd.) at a temperature of 130 ° C., and the cooled product is finely pulverized with a jet pulverizer (Labjet LJ, manufactured by Nippon Pneumatic Industry Co., Ltd.), and a dispersion separator. Classification was carried out with [MDS-II, manufactured by Nippon Pneumatic Industry Co., Ltd.]. Then, 100 parts of toner particles and 1.0 part of colloidal silica (Aerosil R972 manufactured by Nippon Aerosil Co., Ltd.) are uniformly mixed, and toners (T-1) to (T-4) of the present invention having a volume average particle diameter of 9 μm, and Comparative toners (RT-1) to (RT-4) were obtained.
The volume average particle diameter was measured with a Coulter counter (Multisizer TM3, manufactured by Beckman Coulter, Inc.).

[Test example]
Table 2 shows the evaluation results of toners (T-1) to (T-4) and (RT-1) to (RT-4).
As shown in Table 2, the toners (T-1) to (T-4) of the present invention using the toner binders (TB-1) to (TB-4) of the present invention have excellent low-temperature fixability. In addition, it has hot offset resistance and is excellent in image stability. On the other hand, the comparative toners (RT-1) to (RT-4) using the comparative toner binders (RTB-1) to (RTB-4) have a low fixing temperature range and image stability such as fogging. It was inferior. As described above, by using the toner binder of the present invention, it is possible to obtain a toner having no problem in image quality deterioration particularly when the toner is used for a long time.

  The toner binder for electrophotography of the present invention can provide a low level fixing property and hot offset resistance as a toner at a high level, and can further obtain an excellent toner free from troubles such as image quality deterioration when used for a long time. Is extremely useful.

Claims (4)

  Styrene (co) polymer (a) having a molecular weight distribution maximum value of 2500 or more and 5000 or less, a styrene (co) polymer (b) having a molecular weight distribution maximum value of more than 5000 and 200,000 or less, and a molecular weight distribution maximum value of 200,000. It contains a styrene (co) polymer (c) that is greater than 1 million and has a weight ratio of (a) :( b) :( c) = (30-44) :( 5-45) :( 12 -45) containing a styrene (co) polymer (A) and a hydrocarbon wax (F) having a melting point of 65 ° C to 105 ° C, and the weight ratio of (A) to (F) is (92 to 98). ): Toner binder for electrophotography which is (8-2).   The toner binder for electrophotography according to claim 1, wherein at least one of the styrene (co) polymers (a), (b), and (c) comprises two or more kinds of styrene (co) polymers.   The toner binder for electrophotography according to claim 1 or 2, wherein the acid value of the styrene (co) polymer (A) is 0.2 to 12.   A toner containing the electrophotographic toner binder according to claim 1 and a colorant.