JPH04170556A - Manufacture of toner binder resin and electrostatic charge picture developing toner and developer - Google Patents

Abstract

PURPOSE:To obtain an electrostatic charge picture developing toner excellent in also offset prevention while in a fixing property in the case of heat roll fixing by continuously heat-melting 10 to 90 wt.% resin of number average molecular weight 1000 or more under no solvent, and continuously dripping a styrene monomer or a 90 to 10 wt.% mixture of the styrene monomer with the other vinyl system monomer, in this heat melted object, continuously polymerized. CONSTITUTION:10 to 90 wt.% resin of number average molecular weight 1000 or more is continuously heat-melted under no solvent, and a styrene monomer or a 90 to 10 wt.% mixture of the styrene monomer with the other vinyl monomer is continuously dripped in this melted object and continuously polymerized. The heat-melted resin is provided with the number average molecular weight especially preferably 2000 to 5000. In this way, a toner excellent in also offset prevention while in a fixing property can be obtained.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for producing a toner binder resin used in a toner for developing an electrostatic image for developing electrostatic latent images in electrophotography, electrostatic recording, etc. The present invention relates to toner and developer for developing charge images.

[Conventional technology]

Recently, in electrophotographic copying machines, a heated roll fixing method is most commonly used because of its high thermal efficiency, excellent fixing properties, and the ability to miniaturize the device. In particular, for high-speed fixing, a hot roll fixing method is generally used. However, in this fixing method, the toner is softened by heating and becomes sticky, so that a so-called offset phenomenon occurs in which a portion of the toner adheres to the surface of the hot roll.

Conventionally, various fixing devices, fixing methods, etc. have been proposed in order to prevent this offset phenomenon. For example, the surface of the hot roll is formed of a material with excellent mold releasability, such as a fluororesin, and the surface is further coated with an anti-offset liquid such as silicone oil. Although this method is extremely effective in preventing the offset phenomenon, the anti-offset liquid is heated and deteriorates, producing a strange odor, and requires a device to supply the anti-offset liquid, making the copying machine bulky. The mechanism of the copying machine becomes complicated, and high precision is required to obtain stability, resulting in an increase in cost. For this reason, methods are being considered that can prevent the offset phenomenon by not using all of the offset prevention liquid or by using only a small amount to the extent that supply, etc., is not a problem.
No. 1 describes that the offset phenomenon can be prevented by incorporating a small amount of low molecular weight polypropylene into the toner.

On the other hand, studies are also being conducted on binder resins for toner. For example, Japanese Patent Publication No. 51-23354 describes the use of a crosslinkable polymer as a toner binder resin. Also, JP-A-50-1346
No. 52 describes a method of using a resin with a large molecular weight distribution as a binder resin for toner;
No. 220746 and No. 59-226358 describe a method in which a binder resin having a peak molecular weight in two parts, low molecular weight and high molecular weight, is used in a toner. Furthermore, JP-A-58-68752 and JP-A-58-1
Publication No. 02246 describes a method of using a vinyl polymer obtained by graft copolymerizing a modified epoxy resin having a vinyl group and a polyester resin having a vinyl group as a toner binder resin. These methods are effective in preventing the offset phenomenon.

The manufacturing methods for these resins include solution polymerization, suspension polymerization, emulsion polymerization, or a combination of these methods, and the common feature is that they widen the molecular weight distribution of the resins.

[Problem to be solved by the invention]

However, the solution polymerization method requires a step of removing the solvent, and the suspension and emulsion polymerization methods require steps such as dehydration and drying, resulting in a problem that they are economically inferior.

An object of the present invention is to provide a toner for developing an electrostatic image that has excellent fixing properties in hot roll fixing and is also excellent in anti-offset properties, and a method for easily and inexpensively producing a binder resin used in the toner. .

[Means to solve the problem]

The present invention uses resins 10 to 9 having a number average molecular weight of 1000 or more.
0% by weight is continuously melted under heat in the absence of a solvent, and 90 to 10% by weight of a styrenic monomer or a mixture of a styrene monomer and another vinyl monomer is continuously added to this melt. dripping,
A method for producing a binder resin for a toner characterized by continuous polymerization, a toner for developing an electrostatic image containing the binder resin obtained by the production method, and a developer containing the toner together with a carrier. Regarding.

In the present invention, the weight average molecular weight (Mw) and number average molecular weight (Mn) are shown as values measured by gel permeation chromatography (hereinafter abbreviated as GPC) using a standard polystyrene calibration curve. .

The resin to be thermally melted in the present invention has a number average molecular weight of 1
000 or more, preferably 1000 to 7000, particularly preferably 2000 to 5000. If the number average molecular weight is less than 1000, a phenomenon occurs in which the toner is crushed in the developing machine. If it exceeds 7,000, the viscosity during hot melting becomes high, making it difficult to polymerize the monomer.

In addition, fixing properties also tend to decrease.

In the present invention, the resin to be thermally melted preferably has a degree of molecular weight dispersion (weight average molecular weight/number average molecular weight) of 5 or less. When it exceeds 5, the viscosity during hot melting becomes high and polymerization of the monomer becomes difficult.

In the present invention, the resin to be thermally melted is 10 to 90% by weight, preferably 20 to 7% by weight, based on the total amount of the monomers to be mixed.
0% by weight used. If the amount of heat-fused resin is less than 10% by weight, toner fixing performance will deteriorate, and if it exceeds 90% by weight, offset resistance will be insufficient.

Examples of resins to be thermally melted in the present invention include polyester resins, epoxy resins, vinyl resins, etc., and styrene monomers (e.g. styrene, α-
Styrenic monomers (methylstyrene, vinyltoluene, etc.) or copolymers of styrene monomers and other vinyl monomers (e.g. acrylic esters, methacrylic esters, acrylonitrile, acrylamide, etc.) Polymers are preferred.

In the present invention, the styrene monomer and other vinyl monomers that are continuously added dropwise to the continuously heat-melting resin include styrene, α-methylstyrene, p-methylstyrene (vinyltoluene), p-methylstyrene, -t-butylstyrene,
Styrenic monomers such as p-chlorostyrene, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate , decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, glycidyl methacrylate, methoxyethyl methacrylate, propoxyethyl methacrylate, butoxyethyl methacrylate, methoxydiethylene glycol methacrylate, methoxyethylene glycol methacrylate, butoxytriethylene glycol methacrylate, Methoxydipropylene glycol methacrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene glycol methacrylate, benzyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, dicyclopentenyl methacrylate, dicyclopentenyloxy methacrylate Ethyl, N-vinyl-2 methacrylate
-pyrrolidone, methacrylateryl, methacrylamide, N-methylolmethacrylamide, methacrylic acid 2-
hydroxyethyl, hydroxypropyl methacrylate,
Hydroxybutyl methacrylate, 2-hydroxy-3-phenyloxypropyl methacrylate, diacetone acrylamide, acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, acrylic acid Heptyl, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, glycidyl acrylate, methoxyethyl acrylate, propoxyethyl acrylate, butoxyethyl acrylate, methoxydiethylene glycol acrylate, ethoxydiethylene glycol acrylate , methoxyethylene glycol acrylate, butoxytriethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxytetraethylene glycol acrylate, benzyl acrylate, cyclohexyl acrylate, tetrahydrofuric acrylate Furyl, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, N-vinyl acrylate
2-pyrrolidone, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, 2-hydroxy-3-phenyloxypropyl acrylate, glycidyl acrylate, acrylonitrile, acrylamide, N-methylolacrylamide, diacetone acrylamide, vinylpyridine Examples include monofunctional vinyl monomers such as. In addition, divinylbenzene, reaction products of glycol and methacrylic acid or acrylic acid, such as ethylene glycol dimethacrylate, 1゜3-butylene glycol dimethacrylate, 1゜4-butanediol dimethacrylate, 1.5-bentanediol dimethacrylate , 1,6-hexanethiol dimethacrylate, neopentyl glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tripropylene glycol dimethacrylate, hydroxypivalic acid neopentyl glycol ester dimethacrylate, trimethylolethane Trimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, trismethacryloxethyl phosphate, bis(methacryloyloxyethyl)hydroxyethyl isocyanurate,
Tris (methacryloyloxyethyl) isocyanurate, ethylene glycol diacrylate, 1゜3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-bentanediol diacrylate, 1,6-hexanediol diacrylate, Neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate hydroxypivalate, trimethylolethane triacrylate, trimethylolpropane triacrylate, pentaeri trit triacrylate, pentaerythritol tetraacrylate, tris acryloxyethyl phosphate, bis(methacryloyloxyethyl) hydroxyethyl isocyanurate, tris(methacryloyloxyethyl) isocyanurate, half ester of glycidyl methacrylate and methacrylic acid or acrylic acid, A polyfunctional vinyl monomer having two or more vinyl groups in one molecule, such as glycidyl acrylate and a half ester of methacrylic acid or acrylic acid, is used as a copolymerization component of 0 to 1 in the total amount of monomers.
They can also be used together in a range of 0% by weight.

In the present invention, the styrenic monomer or the styrene monomer and other vinyl monomers that are continuously added dropwise to the resin melt in the absence of solvent are 90 to 90% of the total amount of the styrene monomer and the melt. 10
It is used in an amount of 80 to 30% by weight, preferably 80 to 30% by weight. If it exceeds 90% by weight, the toner fixing performance will deteriorate, and if it is less than 10% by weight, the offset resistance will be insufficient.

In the present invention, the styrenic monomer or the styrene monomer and other vinyl monomer are polymerized in the presence of a polymerization initiator. As a polymerization initiator, benzoyl peroxide, 2-ethylhexyl perbenzoate, lauroyl peroxide, di-tert
-butyl peroxide, tert-butyl peroxide, cumene hydroperoxide, methyl ethyl ketone hydroperoxide, 4.4.6 - trimethylcyclohexanone di-tert-butyl peroxyketal, cyclohexanone peroxide, methylcyclohexanone peroxide, acetylacetone peroxide, cyclohexanone di-tert-butyl peroxide Peroxide radical initiators such as ketal, 2-octanone di-tert-butyl peroxy ketal, acetone di-tert-butyl peroxy ketal, diisopropylbenzene hydroperoxide, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, 2,2'-azo Bisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2゜2'-azobis(4-methoxy-2,4-
dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate, 1,1'-azobis(cyclohexane-
Examples include azobis-based radical initiators such as 1-carbonitrile). These polymerization initiators are preferably used in an amount of 0.01 to 10% by weight, particularly preferably 0.1 to 5% by weight, based on the total amount of monomers.

In addition, during polymerization, butyl mercaptan, octyl mercaptan, dodecyl mercaptan, methyl 2-mercaptopropionate, ethyl 2-mercaptopropionate, butyl 2-mercaptopropionate, octyl 2-
Mercaptans such as mercaptopropionate, pentaerythritol tetra(2-mercaptopropionate), ethylene glycol di(2-mercaptopropionate), glycerin tri(2-mercaptopropionate), chloroform, bromoform, tetra(2-mercaptopropionate), etc. Radical polymerization molecular weight modifiers such as halogenated hydrocarbons such as carbon bromide can also be used. These molecular weight regulators are preferably used in an amount of 0 to 3% by weight based on the total amount of monomers.

The manufacturing method of the present invention carried out using each of the above materials includes the first
It is carried out using a continuous polymerization apparatus as shown in the figure.

In FIG. 1, a melting tank 1 and a monomer tank 2 are each connected to a merged flow path 8 via a pump 3. A heater 4 is installed around the overlapping flow path 8 so as to heat the overlapping flow path 8 to a temperature that allows polymerization. A baffle plate 5 is further installed in the overlapping flow path 8, and a resin container 7 is installed at the end of the overlapping flow path 8 via a pressure regulating valve 6.

As for the manufacturing order, first, a resin to be melted is put into a melting tank 1 and heated to a molten state. Monomer tank 2
A mixture of monomers, polymerization initiators, etc. is added to the solution. Next, the pump 3 is adjusted to continuously supply the melt from the melting tank 1 into the superposition channel 8, and at the same time, the pump 3 of the monomer tank 2 is adjusted to continuously supply the melt into the melt. Add monomer dropwise. By adjusting each pump 3, it is possible to determine the mixing ratio of melt and monomer and the residence time in the polymerization apparatus. The mixture flows through the overlapping flow channel 8 (during which it polymerizes and is continuously discharged as a polymer into the resin container 7).

The obtained toner binder resin was measured using a differential scanning calorimeter (D
The peak of the glass transition point measured by SC) is 40 to 100
°C1 is preferably designed to be 55 to 85 °C. Here, the peak of the glass transition point is the temperature at which the endotherm associated with the glass transition reaches a maximum in the endothermic behavior measured by DSC.

The obtained toner binder resin can be further melt-mixed with a colorant and/or magnetic powder, if necessary, a charge control agent, and other additives to form the electrostatic image developing toner of the present invention.

The toner for developing electrostatic images preferably contains the toner binder resin in an amount of 20 to 95% by weight, particularly preferably 40 to 95% by weight.
Contains 85% by weight. If the toner binder resin is less than 20% by weight, fixing properties and fixing strength will be insufficient, and
The image tends to deteriorate, and the binder resin
If it exceeds 5% by weight, the colorant and/or magnetic powder will be insufficient, resulting in a decrease in image density, as well as poor charging properties, resulting in a decrease in developability, making it impossible to obtain beautiful images.

As the coloring agent, conventionally known colorants such as carbon black, iron oxide pigment, phthalocyanine blue, phthalocyanine green, rhodamine 6G lake, watching red barium, watching red strontium, etc. can be used, and 1 to 60% by weight of the coloring agent is used in the toner. It is selected and used as appropriate within the range.

Examples of magnetic powder include fine metal powders such as iron, manganese, nickel, and cobalt, and ferrites such as iron, manganese, nickel, cobalt, and zinc, with an average particle size of 10μ.
It is preferably 1 μm or less, particularly 1 μm or less, and is usually used in the toner in an amount of 0 to 70% by weight. When using magnetic powder, the coloring agent may not be used because the magnetic powder has a coloring effect.

As the charge control agent, nigrosine dyes, fatty acid-modified nigrosine dyes, metal-containing nigrosine dyes, metal-containing fatty acid-modified nigrosine dyes, chromium complexes of 8,5-di-tert-butylsalicylic acid, and the like can be used. It is used in an amount of 0 to 20% by weight.

Other additives that can be used include silica powder, hydrophobic silica powder, polyolefin, paraffin wax, fluorocarbon compounds, fatty acid esters, partially saponified fatty acid esters, fatty acid metal salts, etc. % by weight used.

These materials can be mixed, for example, by the method described below to produce a toner for developing electrostatic images.

The weighed materials are premixed using a W cone, a blender, a Henschel mixer, etc., and then kneaded using a pressure kneader, a Banbury mixer 1 hot roll, an extruder, etc. at a temperature at which the resin melts. After cooling, it is coarsely ground using a feather mill, bottle mill, pulverizer, hammer mill, etc., and then finely ground using a jet air mill. Then, it is sieved using an Accucut, Albine classifier, etc., preferably 5 to 3
Adjust the particle size to 0 μm. Note that a fluidity modifier such as silica powder can also be simply mixed.

Furthermore, the above toner can be combined with a carrier to form the developer of the present invention. As a carrier, iron oxide powder of various shapes such as flat, cavernous, coin-shaped, spherical, and true spherical, as well as manganese, cobalt, nickel, zinc,
Ferrite such as tin, magnesium, lead, strontium, barium, lithium, iron oxide powder and ferrite coated on the surface of Teflon resin, acrylic resin, polyester resin, silicone resin, melamine resin, butadiene resin, butyral resin, etc. Examples include particles made of a kneaded product of resin and magnetic powder.

The toner concentration of the developer generally depends on the specific surface area of the carrier, and is 3 to 10% by weight when the carrier used is amorphous or has a fine particle size, and 1 to 10% by weight when the carrier is spherical or has a coarse particle size.
Preferably it is 5% by weight.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The resins of the following Examples and Comparative Examples were all produced using a continuous polymerization apparatus having the shape and size shown in FIG.

Example 1 A copolymer of styrene and methyl methacrylate (former/latter = 90/10 weight ratio) (number average molecular weight 2500, weight average molecular weight/number average molecular weight = 2) was placed in the melting tank 1.
．． 5) was added and heated to 180°C to make it into a molten state.

Monomer tank 2 was charged with a mixture of styrene (75 parts by weight), acrylic acid butyl ester (25 parts by weight) and di-tert-butyl peroxide (0.5 parts by weight). Then, the residence time was adjusted to 2.5 hours, and the weight ratio of the hot melt to the monomer was adjusted to be 40/60, and bulk polymerization was carried out continuously. The polymer is continuously taken out into a metal vat,
Cooled to room temperature. Thereafter, it was coarsely ground to a size of 1 to 5 mm to obtain a solid resin.

Example 2 In Example 1, the weight ratio of resin melt and monomer was 20.
The same procedure as in Example 1 was carried out except that adjustment was made so that the ratio was /80.

Example 3 In Example 1, the weight ratio of resin melt and monomer was 60.
The same procedure as in Example 1 was carried out except that the ratio was adjusted to be /40.

Example 4 A copolymer of styrene and butyl acrylate (former/latter = 90/10 weight ratio) (number average molecular weight 3500, weight average molecular weight/number average molecular weight = &0) was placed in a melting tank.
The same procedure as in Example 1 was carried out except that .

Example 5 The same procedure as in Example 1 was carried out except that a mixture of styrene (60 parts by weight), butyl methacrylate (40 parts by weight) and di-tert-butyl peroxide (0.5 parts by weight) was placed in the monomer tank. Ta.

Example 6 The same procedure as in Example 1 was carried out except that the dropping rate was adjusted so that the residence time was 5 hours.

Example 7 In Example 1, a copolymer of styrene and methyl methacrylate (former/latter = 90/10 weight ratio) (number average molecular weight 8500, weight average molecular weight/number average molecular weight = 4.1') was placed in the melting tank in Example 1. ) Example 1 except that
I did the same thing.

Comparative Example 1 In Example 1, the styrene-methyl methacrylate copolymer was not used, and styrene (
Example 1 was repeated except that only a mixture of 75 parts by weight), butyl acrylate (25 parts by weight) and di-tert-butyl peroxide (0.5 parts by weight) was added dropwise.

Comparative Example 2 In Example 1, the weight ratio of the hot melt and the monomer was changed to 90/
The same procedure as in Example 1 was carried out except that the adjustment was made so that the number of particles was 10.

The properties of the resins obtained in Examples 1 to 7 and Comparative Examples 1 to 2 are summarized in Table 1. In addition, Tg was measured by the DSC method, and the molecular weight was measured by the GPC method.

Example 8 (1) Production of toner and developer 450 g of resin produced in Examples 1 to 7 and Comparative Examples 1 to 2
, carbon black (#44, manufactured by Mitsubishi Chemical Corporation) 40
g, 10 g of Viscol 550P (trademark, low molecular weight polypropylene manufactured by Sanyo Chemical Industries, Ltd.) and oil black BY
(Trademark, Nigrosine dye manufactured by Orient Chemical Industries) 2
5 g was heat-melted and kneaded using a co-kneader mixer, and then coarsely ground using a hammer mill. Subsequently, it was finely pulverized using a jet air mill. This was classified to obtain a toner having a particle size of 5 to 30 μm and an average particle size of 12 μm.

Next, 50g of toner obtained in this way and EVF200/30
0 (trademark, amorphous iron oxide powder carrier manufactured by Powder Tick) were mixed with 950 g of the powder and thoroughly shaken to prepare a developer.

(2) Evaluation of toner (a) Storage stability Approximately 5 g of toner was placed on a glass petri dish to a uniform thickness and stored in a constant temperature and humidity chamber at a temperature of 55° C. and a humidity of 90% for 24 hours. This was sieved through a 100-mesh wire mesh, and the weight of the material passing through was measured. Storage stability was evaluated in five stages according to the following criteria.

Judgment criteria: 5: 95% by weight or more passed 4 Near 0% or more but less than 95% by weight passed 3: 30% by weight
More than 70% by weight passed 2: 5% by weight or more and less than 30% by weight passed 1: Less than 5% by weight passed (b) Blow-off charge amount Measured using a blow-off charge amount measuring device manufactured by Toshiba Chemical ■.

(c) Fixing properties and anti-offset properties A developer was put into a test machine which was an improved copying machine of the Sharp Renki 5F755 model, and an unfixed image with the top 1/3 of an A4 size plate being solid black was created.

This unfixed image was tested by changing the temperature in a 10°C range from 100°C to 240°C using a Teflon roll fixing tester and fixing it at a linear speed of 900 an/min (A4 size, approximately 40 sheets/min). . The fixing temperature is the lowest temperature at which the rate of change in image density is 10% or less after removing cellophane tape from the fixed black solid area, and the offset generation temperature is the temperature at which the reflection density of the white paper part where the offset of the black solid area occurs is black. The lowest temperature was set at 0.2% or more compared to the solid area.

(ci) Actual machine copying test Put developer into a 5F755 copying machine manufactured by Sharp Mono
A continuous copying test of 0,000 sheets was conducted, and the initial image and 100
After copying 00 sheets, changes in the image and the state of toner scattering were observed.

! - ~, 211111 [Effects of the invention] The manufacturing method of the present invention can simplify the process compared to the conventional method,
By using the binder resin for toner which is easily and inexpensively produced and has excellent economic efficiency, it is possible to obtain a toner which has excellent fixing properties and excellent anti-offset properties in a hot roll fixing method. Toners and developers using the toner binder resin of the present invention are excellent in fixing properties, anti-offset properties, durability, and storage stability.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a continuous polymerization apparatus used in the production method of the present invention. Explanation of symbols 1... Melting tank, 2... Monomer tank, 3...
・Pump, 4... Heater, 5... Baffle plate, 6...
・Pressure regulating valve, 7... Resin container, 8... Overlapping flow path

Claims (1)

[Claims] 1. 10 to 90% by weight of a resin having a number average molecular weight of 1000 or more is continuously heated and melted in the absence of a solvent, and this melt is added with a styrenic monomer or a styrene monomer and other substances. 1. A method for producing a binder resin for toner, which comprises continuously dropping 90 to 10% by weight of a mixture with a vinyl monomer and polymerizing continuously. 2. The method for producing a binder resin for toner according to claim 1, wherein the resin having a number average molecular weight of 1,000 or more is a styrene polymer having a number average molecular weight of 1,000 to 7,000 and a molecular weight dispersity of 5 or less. 3. A toner for developing electrostatic images containing a binder resin obtained by the manufacturing method according to claim 1 or 2. 4. A developer comprising the toner according to claim 3 together with a carrier.