JPH0387753A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To obtain a toner superior in fixability and offset resistance by using a binder resin comprising a vinyl copolymer obtained by reacting a vinyl macromonomer having a vinyl group at one of the terminals and a number average molecular weight of 5X10<2> - 5X10<4> with another vinyl monomer, and another vinyl copolymer. CONSTITUTION:The binder resin comprises the vinyl copolymer having a number average molecular weight of 6X10<3> - 1X10<6> obtained by reacting the vinyl macromonomer having a vinyl group at one of the terminals and a number average molecular weight of 5X10<2> - 5X10<4> with another vinyl monomer, preferably, such as, styrene, acrylic acid, acrylate, methacrylic acid, or methacrylate, alone or in combination, and at least one of vinyl copolymers, thus permitting offset resistance to be enhanced and stable successive copying to be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a toner for an electrostatic image developer for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like.

[Conventional technology]

Electrophotography generally uses a photoconductive substance to form an electrostatic charge image on a photoreceptor by various means, develops this electrostatic charge image with toner, and then transfers it to a transfer device such as paper and then heats it. The paper is fixed on the paper transfer machine using a constant roller fixation method. This fixing method uses heat and pressure, and is quick and thermally efficient, and has excellent fixing efficiency. On the other hand, in the fixing method described above, the toner image is brought into direct contact with the surface of the heat roller, and the toner image is melted by heating and pressure and fixed onto paper, etc.
A part of the toner image adheres to the surface of the fixing roller and transfers.
Furthermore, this transferred material is transferred again to the next transfer machine, causing a so-called offset phenomenon, resulting in staining the paper note transfer machine.

Generally, in the above fixing method, the lower the melt viscosity, that is, the molecular weight, of the binder resin, the better the fixing efficiency, and the higher the melt viscosity, that is, the molecular weight, the better the offset property.
The combination of low molecular weight polymers and high molecular weight polymers is widely used, and in particular, styrene/acrylic polymers whose molecular weights can be easily adjusted are often used. That is, for example, JP-A-50-134652 and JP-A-50-13324.
As seen in Publication No. 2, attempts have been made to simultaneously improve fixing properties and offset properties by using low molecular weight styrene/acrylic resins and high molecular weight styrene/acrylic resins as binder resins. However, with the rapid development of the information society in recent years, there has been a demand for faster recording copying and clearer images in fields such as electrophotography, and this demand is especially great for color copies. The methods described in the above-mentioned publications are insufficient, and there is a strong demand for improvement in the fixing properties and offset properties of the binder resin body.

[Problem to be solved by the invention]

The present invention provides a toner with excellent fixing properties and anti-offset properties.

[Means to solve the problem]

The present invention relates to a vinyl polymer having a vinyl group at one end and a number average molecular weight of 5xto'' to 5x104 (hereinafter referred to as macromonomer), which is obtained by reacting with another vinyl monomer. Average molecular weight is 6x103~1x10
An object of the present invention is to provide a toner for developing an electrostatic image using a binder resin comprising a vinyl copolymer (A,) of No. 6 and one or more other vinyl copolymers (B).

The number average molecular weight of the macromonomer in the present invention is 5×1
If it is less than 5 x 102, sufficient anti-offset properties cannot be obtained, and if it exceeds 5 x 104, fixing properties will be insufficient. The terminal vinyl group of the macromonomer is not particularly limited as long as it can undergo radical polymerization, but methacryloyl and acryloyl groups are particularly preferred from the viewpoint of copolymerizability with styrene/acrylic esters and methacrylic esters. preferable.

Furthermore, the vinyl monomer constituting the main chain of the macromonomer is not particularly limited, and examples include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, cyclohexyl acrylate, and acrylic. lauryl acid, stearyl acrylate,
Acrylic acid esters such as benzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, hydroxyethyl acrylate, hydroxybutyl acrylate, methyl methacrylate, ethyl methacrylate,
Propyl methacrylate, butyl methacrylate, octyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate,
benzyl methacrylate, frifuryl methacrylate,
Methacrylic acid esters such as tetrahydrofurfuryl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate, aromatic vinyl monomers such as styrene, vinyltoluene, α-methylstyrene, and chlorostyrene. unsaturated dibasic acid dialkyl esters such as dibutyl maleate, dioctyl maleate, dibutyl fumarate, dioctyl fumarate, vinyl esters such as vinyl acetate and vinyl propionate, acrylonitrile, methacrylonitrile, etc. Nitrogen vinyl monomer, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, cinnamic acid, unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, monomethyl maleate, monoethyl maleate, Unsaturated dicarboxylic acid monoesters such as monobutyl maleate, monooctyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monooctyl fumarate, dimethylaminoacrylate, diethylaminoacrylate, dimethylaminomethacrylate, diethylaminomethacrylate, etc. Examples include alkylaminoacrylates, methacrylates, fluorinated acrylates, methacrylates, vinylsilanes, etc. alone or in mixtures.

However, styrene, acrylonitrile, acrylic acid, acrylic ester, methacrylic acid, methacrylic acid Esters are particularly preferred. In addition, from the point of view of offset resistance, the number of carbon atoms in the alkyl group of acrylic acid or methacrylic acid is 10 to 20.
Particularly preferred are alkyl esters.

The macromonomer used in the present invention can be synthesized by, for example, the methods disclosed in Japanese Patent Publication No. 43-16147, Japanese Patent Publication No. 1-132601, etc., but is not limited to these synthesis methods.

Furthermore, depending on the synthesis method used in the present invention, macromonomers having vinyl groups at both ends may be mixed, but if a large number of macromonomers with vinyl groups at both ends are mixed, the copolymer becomes insoluble and infusible. Although this is not preferable as it significantly reduces fixing properties, it can be used as the one-end vinyl macromonomer of the present invention if the content of the vinyl-end macromonomer is 10% by weight or less.

Other vinyl monomers to be copolymerized with the macromonomer in the present invention are not particularly limited by the type of the monomer, and include various monomers and divinyl monomers exemplified as monomers constituting the main chain of the macromonomer. Examples include divinyl compounds such as benzene and ethylene glycol dimethacrylate, but styrene, acrylic acid, acrylic esters, methacrylic acid, and methacrylic esters may be used alone or in combination from the viewpoint of crushability during toner production and toner triboelectric charging properties. More preferred.

The copolymerization ratio of the macromonomer in the vinyl copolymer (A) used in the present invention is preferably in the range of 0.1 to 80% by weight, and if it is 0.1% by weight or less, a sufficient effect of improving offset resistance can be obtained. If the weight is 80 weight or more, the fixing performance will be poor, which is not preferable.

Moreover, the weight average molecular weight of the vinyl copolymer (A) is preferably 6×10 3 to 1×IO &, more preferably 1.5.
The weight average molecular weight is in the range of 1.times.10@4 to 1.times.10@6, and if the weight average molecular weight is within this range, offset resistance and fixing properties will be even better.

Further, in the present invention, the binder resin is constituted together with the vinyl copolymer (A). The vinyl copolymer CB) is not limited by the type of comonomer, but may be any of the monomers mentioned above as the monomer copolymerized with the macromonomer in the vinyl copolymer (A). Although they may be used singly or in mixtures, styrene, acrylic acid, acrylic esters, methacrylic acid, and methacrylic esters are particularly preferred from the viewpoint of crushability during toner production, toner charging characteristics, and the like.

Furthermore, the vinyl copolymer (B) in the present invention may be either a partially crosslinked vinyl copolymer having a partially crosslinked structure or an uncrosslinked vinyl copolymer having no crosslinked structure, but may have offset resistance and Partially crosslinked resin is preferable from the viewpoint of fixing balance, and in the case of uncrosslinked resin, vinyl copolymer (A)
The weight average molecular weight of is 1', 5 x 10' to 1 x 1
06, the weight average molecular weight of the vinyl copolymer (B) is 3X103 to 8XIO', and the vinyl copolymer (B) has a weight average molecular weight of 3X103 to 8XIO'.
A):The weight ratio of vinyl copolymer (B) is (20 to 80
) = weight average molecular weight of the binder resin and vinyl copolymer (A) composed of (80 to 20) is 6X103 to 1X
106, and the vinyl copolymer (B) has a weight average molecular weight of 3 x 103 to 8 x 104 and a weight average molecular weight of 1.5 x 1. A binder resin composed of a vinyl copolymer of O' to 1xio' is particularly preferred.

The method for partially crosslinking the partially crosslinked vinyl copolymer (B) described above is not particularly limited. For example, when producing a vinyl copolymer, a small amount of a divinyl compound is added as one of the comonomers. Copolymerization partial crosslinking method, metal chelate crosslinking type in which a monomer having a carboxyl group, such as methacrylic acid, is copolymerized as one of the vinyl monomers to be copolymerized, and then a metal chelate, such as i-chelate, etc. is reacted. etc. Any one is fine.

As the polymerization method for the vinyl copolymers (A) and (B) in the present invention, any of solution polymerization, suspension polymerization, emulsion polymerization, and bulk polymerization is possible, and is limited by these polymerization methods. It's not something you can do. In addition, vinyl copolymers (
A, ) and (B) may be mixed, melted, and kneaded together with other additives during toner production, or may be homogeneously mixed in advance as a binder resin.

When the vinyl copolymers (A) and (B) according to the present invention are radically polymerized, a polymerization initiator usually used for radical polymerization, such as azobisisobutyronitrile, 2,2'
-Azobis radical polymerization initiator such as azobis(2-methylbutyronitrile), t-butylperoxy 2-ethylhexanoate, benzoyl peroxide, l11
-bis-(t-butylperoxy) 3,3.5-)
A peroxide radical initiator such as remethylcyclohexane is used, and the type thereof is not limited. Further, when carrying out radical polymerization using such a radical polymerization initiator, a chain transfer agent for controlling the molecular weight, typified by n-dodecylmercaptan, α-methylstyrene dimer, etc., may be used if necessary.

Next, a method for manufacturing a toner according to the present invention using the above-mentioned binder resin and a toner formulation will be described.

First, the binder resin according to the present invention is crushed and mixed with carbon black, a benzidine-based yellow organic pigment such as pigment yellow, a magenta-colored organic pigment such as xanthine-based pigment Red 8L, quinacridone-based 2.9-dimethylquinacridone, Phthalocyanine-based blue organic pigments such as c
, r, Pigment Blue 15, C, 1, Solvent Blue 0, oil-soluble dye example Eva C, 1, Solvent Red 24, C, r, Solvent Blue dyes and pigments, triboelectricity as necessary. Nigrosine for adjustment, chromium-containing dye, low molecular weight polyolefin to help prevent offset, aliphatic metal salt, silica, and magnetic iron oxide in the case of -component type toner are mixed, blemixed, and extruder pressurized Nigoo etc. The toner is obtained by melting, kneading, and then pulverizing and classifying, and the present invention is not limited by the formulation or manufacturing method of the toner.

The number average molecular weight and weight average molecular weight in the present invention are GP
Method C was used, and the equipment and measurement conditions were as follows.

Equipment LC-08 type column manufactured by Nippon Analytical Industry ■: A-806+A-805+A-804+A-
803+A-802 solvent': THF, discharge amount: 1. bi
! , 7 minutes, Sample: o, 1xTHF solution [Example] The present invention will be described in detail below with reference to Examples and Comparative Examples. Note that the number of parts in Examples and Comparative Examples is based on weight.

(Synthesis Example-A-1) In a flask equipped with a condenser, an N2 gas inlet tube, and a stirrer, 66 parts of styrene, 22 parts of n-butyl acrylate, 8 parts of methyl methacrylate, and macromonomer As-6 (manufactured by Toagosei Kagaku Kogyo ■, one end Charge 4 parts of methacryloyl type polystyrene with main chain structure (Mn=6X103) and dissolve it uniformly, then add 200 parts of ion-exchanged water, 3 parts of hydroxyethyl cellulose, and 0.22 parts of 1,4-bis(L-butylperoxycarbonyl)cyclohexane. and 0.55 parts of benzoyl peroxide, and heated for 90' under a stream of N2 gas.
Polymerization was carried out with stirring at C for 24 hours. Thereafter, the mixture was cooled, the crowbar was washed with water, and dried to obtain a vinyl polymer having a vinyl-terminated macromonomer. The weight average molecular weight (hereinafter referred to as Mw) of the obtained copolymer was 4.2×10 3 . Below, Synthesis Example-A
Vinyl 1 of one-end vinyl type macromonomer according to -1
Compounds A-2 to 8-8 were synthesized. The contents are shown in Table-1.

(Example B-1) Pour 100 parts of xylene into a flask equipped with a condenser, N2 gas inlet pipe, and stirrer, and N! The temperature was raised to 130°C with stirring under a gas stream, and a mixture of 88 parts of styrene, 5 parts of n-butyl acrylate, 7 parts of methyl methacrylate, and 6 parts of t-butylperoxy 2-ethylhexanoate was added to 8
The mixture was added dropwise over a period of time, and after completion of the dropwise addition, polymerization was carried out for 15 hours. Next, a solvent and a vinyl copolymer were obtained under reduced pressure. The Mw of the obtained copolymer was 7.6×103.

(Synthesis Example B-2) Bottom example A-1 except that 70 parts of styrene, 22 parts of n-butyl acrylate, 8 parts of methyl methacrylate, and 0.1 part of benzoyl peroxide were used as copolymerization monomers.
A copolymer was obtained in exactly the same manner. The Mw of the obtained copolymer was 2 x 103.

(Combined example B-3) In the same manner as Synthesis 11MB-1, 40 parts of Kijirole was charged, the temperature was raised to 135°C with stirring, and under a stream of N2 gas, 48 parts of styrene, 1.12 parts of n-butyl acrylate, and ethylene glycol were added. A mixture of 0.38 parts of dimethacrylate and 0.38 parts of di-t-butyl peroxide was added dropwise over a period of 4 hours, and after the addition was completed, polymerization was carried out for 6 hours, followed by partial crosslinking by reducing the pressure, heating, and removing the solvent. A vinyl polymer was obtained.

(Examples 1 to 12, Comparative Examples 1 to 3) Synthesis Examples A-1 to A-8 and Synthesis Examples B-1 to B-3 were blended in a predetermined composition. Next, binder resin:xylene was blended so that the ratio was 100 to 0 (weight ratio), heated to uniformly dissolve, and the solvent was removed under reduced pressure to obtain binder resins corresponding to Examples and Comparative Examples. 100 parts of the obtained binder resin, 5 parts of carbon black, 2 parts of Bontron S-34 (before chromium complex salt charge control, manufactured by Orient Chemical Co., Ltd.), 0 or 4 parts of Viscol 550P (low molecular weight polypropylene wax, manufactured by Sanyo Chemical Co., Ltd.) After melting and kneading with a pressure kneader, the mixture was pulverized with a jet mill, and particles with a particle size of 5 to 15 μm were classified and collected to obtain a toner with an average particle size of about 12 μm. A developer was prepared by mixing 7 parts of the obtained toner and 93 parts of iron powder carrier, and an image was produced using a commercially available electrophotographic copying machine.
A fixing test was conducted using a heat roll fixing device with a speed of mm/sec. Table 2 shows the composition of the binder resin used in Examples and Comparative Examples and the composition of Viscol 550P in the toner composition, and Table 3 shows the results of the toner formation test.

Table 2 Table 3 (Effects of the Invention) The present invention can provide a toner for developing electrostatic images that has excellent offset resistance5 and continuous copying properties.

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Claims (5)

[Claims] (1) Has a vinyl group at one end and has a number average molecular weight of 5
A type of vinyl copolymer (A) and other vinyl copolymer (B) obtained by reacting a vinyl polymer having a molecular weight of x10^2 to 5 x 10^4 with another vinyl monomer. A toner for developing an electrostatic image using a binder resin comprising the above. (2) The toner for developing electrostatic images according to claim 1, wherein the binder resin contains 1 to 70% by weight of the vinyl copolymer (A). (3) Vinyl copolymer (A) is vinyl polymer 0.1
2. The toner for developing electrostatic images according to claim 1, comprising 80% by weight of vinyl monomer and 20-99.9% by weight of other vinyl monomers. (4) The weight average molecular weight of the vinyl copolymer (A) is 6×
10^3 to 1 x 10^6, the weight average molecular weight of the vinyl copolymer (B) is 3 x 10^3 to 8 x 10^4, and the vinyl copolymer (A): vinyl copolymer The toner for developing an electrostatic image according to claim 1, wherein the weight ratio of the combined (B) is (20-80):(80-20). (5) The toner for developing electrostatic images according to claim 1, wherein the vinyl copolymer (B) is partially crosslinked.