JPS6356661A - Preparation of toner resin - Google Patents

Abstract

PURPOSE:To improve offset resistance of a toner and to widen a fixing temperature range by using a resin having a gel fraction obtained by polymerizing a mixture of a linear polymer, a polymerizable monomer, and a cross-linking agent. CONSTITUTION:The resin having a gel fraction is prepared by polymerizing a mixed solution of the linear polymer, preferably, such as a copolymer of a styrene derivative monomer and a (meth)acrylate derivative monomer, and preferably, having a melt viscosity of 1-2,000 poise at 160 deg.C, the polymerizable monomer, such as styrene, and the cross-linking agent, such as divinylbenzene. The gel fraction of the resin composed of the copolymer of said 3 components amounts, preferably, to 5-60wt% of the resin, thus permitting the obtained toner to be wide in the fixable temperature range, and superior in resistances to offset and plasticizers, and enhanced in image forming performance and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing toner resin used in electrophotography, etc., and specifically relates to so-called dry development, which is a method of developing electrostatic images. The present invention relates to a method for producing toner resin used in the method.

(Prior art) In the dry development method, the toner is normally charged by friction with iron powder or glass beads called a carrier, which is attached to the electrostatic latent image on the photoreceptor by electrical attraction, and then The image is transferred onto paper and fixed with a heat roll or the like to form a permanent visible image.

The fixing method is a heated roller method in which the toner is passed through a heated roller whose surface is made of a material having moldability while bringing the toner image surface of one electrodeposited sheet into pressure contact with the surface of the heated roller. It is widely used.

This method has a problem in that an offset phenomenon occurs. This is a phenomenon in which part of the toner that forms one image during fixing transfers to the surface of the heat roller, and this transferred toner transfers again to the next sheet of paper, staining the image. In order to prevent this offset phenomenon, using a cross-linked polymer with a high gel content as a toner resin is preferable in terms of offset resistance, but on the other hand, the lowest fixable temperature increases and the fixing temperature range becomes narrower. There was a problem. Therefore, in order to prevent offset development and maintain a wide range of fixing temperatures, it is known that a linear polymer and a crosslinked polymer are blended to form a toner resin (Special F
M chant 59-88748). However, the resin obtained by this method does not necessarily maintain a wide fixing temperature range, and also has plasticizer resistance (even if the paper on which the toner is fixed is brought into contact with a plastic sheet containing a plasticizer, the plasticizer does not change over time). 31! Improvements were requested.

(Problem to be solved by Issue 1) The purpose of the present invention is to solve the above-mentioned conventional toner resin.
It is an object of the present invention to provide a method for producing a resin for a toner, which makes it possible to obtain a toner having excellent offset resistance and a wide range of fixing temperatures (in particular, a low lower limit temperature).

%.An object of the present invention is to provide a method for producing a toner resin that yields a toner with plasticizer resistance, image quality, etc. equal to or better than conventional products.

(Means for Solving the Problems) The method for producing a toner resin of the present invention includes a linear polymer (a
) 1 A mixed solution of a polymerizable monomer (b) and a crosslinking agent (c) is polymerized to obtain a resin having a gel content, thereby achieving the above-mentioned object.

The linear polymer (a) in the present invention is considered to mainly contribute to low fixing humidity of the toner, and preferably has a melt viscosity of about 1 to 2,000 poise at 160°C. If the viscosity is too low, the plasticizer resistance and blocking resistance will generally be poor, and if the viscosity is too high, the fixing temperature will be high.

Linear Bo! Examples of monomers constituting J-'-(a) include t ff , styrene, O-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2.4 -dimethylstyrene, p
-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octyl Z
f-len 1. p-n-nonylstyrene, p-n-7'silstyrene, p-n-dodecylstyrene, p-methoxystyrene, p-7enylstyrene, p-chlorostyrene,
3. Styrenic monomers such as 4-dichlorostyrene; methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic acid 2 - Ethylhexyl, stearyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate,
Acrylic acid or methacrylic acid alkyl esters such as stearyl methacrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. Methacrylic acid ester monomers; esters of double bond-containing dicarboxylic acids such as methyl maleate, butyl maleate, and dimethyl maleate; vinyl ester monomers such as vinyl chloride, vinyl acetate, and vinyl benzoate One example is the body.

These can be used alone or in combination,
It is particularly preferable to use a styrene monomer and an alkyl ester of acrylic acid or methacrylic acid in combination.

In the present invention, a mixed solution of the above-mentioned linear polymer (a), polymerizable monomer (b) and crosslinking agent (c) is polymerized. polymer(
Any monomer that can be used as the structural unit of a) can be used, and it can be the same as the monomer constituting the linear polymer (a), or if two or more types of monomers are polymerized, the same monomers can be used. It is preferable that it contains.

As the polymerization method, any conventionally known polymerization method such as solution polymerization method, suspension polymerization method, emulsion polymerization method, or bulk polymerization method may be adopted, but it is possible to reduce the gel size by chain transfer of solvent. The solution polymerization method is advantageous in that the lower limit of the fixing temperature can be easily lowered because of the ease of Preferably used.

In the solution polymerization method, the trap of preparing a mixed solution of linear polymer (a), polymerizable monomer (b), and crosslinking agent <c) is to Polymer (a
) may be added, or the crosslinking agent (c) may be added after the monomers are polymerized at low temperature and the reaction is interrupted at the initial stage of polymerization.

The crosslinking agent used in the present invention is mainly a monomer having two or more polymerizable double bonds, such as divinylbenzene,
．． 5-hexadien-3-yne, hexatriene, divinyl ether, divinyl ketone, divinyl sulfone, N
, N-divinylaniline, divinyl compounds such as divinyl sulfide, diallyl compounds such as acrylic phthalate, diallyl carbinol, double bonds such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, etc. A carboxylic acid ester having two or more Fi can be used alone or as a mixture of Fi.

The presence of gel content in the resin obtained by the present invention is due to
This is thought to be due to the formation of a crosslinked polymer consisting of the polymerizable monomer (b) and the crosslinking agent (c) (in some cases, the linear polymer (a)), and the higher the ratio (gel fraction), the higher the Offset resistance, plasticizer resistance, blocking resistance, etc. are improved, but if it is too high, the lower limit of the fixing temperature will rise, and if it is too low, effects such as offset resistance will not be expressed, so it is generally 5% by weight. The above content is preferably 10 to 60% by weight. Incidentally, the gel fraction is measured as follows. First, the resin of the present invention is placed in a VC container (w, g) and weighed (Wag). Put a large amount of toluene into a container and let it stand for 24 hours. During this time, shake the container several times to promote the diffusion of resin-soluble components into toluene. After that, the mixture is allowed to stand still for 48 hours or more to allow the gel to settle. The supernatant liquid is removed with a dropper, and the gel content is dried and weighed (Wsg).

It will be done.

Linear polymer (a), polymerizable monomer (b) and crosslinking agent (
The mixing ratio with c) is generally 10:90 to 90 by weight.
: 10, preferably 30 near 0 to 60:40.

The resin obtained by the method of the present invention is a linear polymer (a)
is thought to have a microscopic structure (enveloped structure) in the crosslinked polymer produced by polymerizing the polymerizable monomer (b) and the crosslinking agent (c), and this Therefore, even if the lower limit of the fixing temperature is kept low by using a linear polymer having a low melt viscosity, it has excellent blocking resistance and plasticizer resistance, and the linear polymer (a) and the crosslinked polymer are integrated. Therefore, it is thought that a toner with excellent image quality and a wide range of fixing temperatures can be obtained.

(Example) Example 1 A 21-year flask was charged with 260 g of toluene, and after replacing the air with nitrogen gas, the system was heated to the boiling point of toluene. While stirring toluene under reflux, styrene 83y1, n-butyl acrylate 17g, and benzoyl peroxide 2y as a polymerization initiator were added.
The solution polymerization was carried out by adding dropwise a mixture of the following over 25 hours. (melt viscosity 36 boads at 160°C,
Weight average molecular weight 86001 oak fat a) After completion of the dropwise addition, the mixture is further aged for 1 hour while stirring at the boiling temperature of toluene 1. To this system, a mixture of 73 y of styrene, 22 n-butyl acrylate, and 5 no. of hashivinylbenzene is added. Added. and benzoyl peroxide 3 f f () toluene 10
A mixture heated to 100 yK was added dropwise over 2 hours to carry out a crosslinking reaction. Thereafter, toluene was removed from the solvent under reduced pressure while gradually raising the temperature of the system to 180° C. to obtain a resin. This resin was cooled and pulverized to obtain flaky resin A of the present invention. The gel fraction #″i was 22%.

100 parts by weight of resin A and 5 parts by weight of Carbon Gratuta (Diapcook SH, manufactured by Otoko Mitsubishi Kasei Co., Ltd.) were melt blended, cooled, coarsely pulverized, and further finely pulverized with a jet mill to obtain an average particle size of about 13 to 15 microns. A toner having the following was created.

Four parts by weight of this toner were mixed with 96 parts by weight of an iron powder carrier having an average particle size of about 50-80 microns to form a developer, which was used to obtain copies. The electrophotographic copying machine used was a Fuji Xerox 3500.

For evaluation of plasticizer resistance, agricultural vinyl chloride sheet containing 30% by weight of dioctyl phthalate as a plasticizer was
It was cut into square pieces and attached to a copy using a pressure of lK9, and then left in a constant temperature bath at 60°C for 24 hours to see if the copy would be transferred to the vinyl sheet. No transfer was observed with the developer used.

Regarding the fixing temperature range, the set temperature of the heat roller of the electrophotographic copying machine was varied to determine the set temperature that would allow fixing without causing offset. It was found that the developer using resin A has a wide fixing temperature range from 160°C to 240°C or higher.

The resulting images had no capri and had excellent resolution.

Example 2 In the same manner as in Example 1, a linear styrene/n-butyl acrylate (83/17) copolymer CriI fat b) having a weight average molecular weight of 9000 was obtained. Styrene 130 in this system
A mixture of 10 p.y,/thyl methacrylate, 502 p.m. Then, 62 parts benzoyl peroxide to 100 parts toluene
The solution dissolved in y was added dropwise over 2 hours to carry out a crosslinking reaction. Thereafter, toluene was removed from the solvent under reduced pressure while the temperature of the system was gradually raised to 1 g o'c to obtain a resin.

The gel content was 42%. This resin was cooled and pulverized to obtain resin B in the form of flakes. Toner and developer were prepared in the same manner as in Example 1, and their physical properties were evaluated.

The evaluation results of plasticizer resistance show that for the developer using resin B,
No transcription was allowed.

It has been found that the developer using resin B has a wide fixing temperature range from 160° C. to about 240° C. The resulting images had no capri and had excellent resolution.

Comparative Example 1 Resin a 64 g 64 weight tyrene-n-butyl acrylate divinyl pentene crosslinked polymer (gel fraction 6α3%
) and 5 parts by weight of carbon black (same as in Example 1) were melt-blended, cooled, coarsely pulverized, and further finely pulverized with a jet mill to obtain a toner having an average particle size of about 13 to 15 microns. Created.

This is a blend of the same gel content as in Example 1.

Four parts by weight of this toner were mixed with 96 parts by weight of an iron powder carrier having an average particle size of about 50-80 microns to form a developer, which was used to obtain copies.

In the plasticizer resistance test, slight transfer is observed.

The fixing temperature range was from 170°C to 240°C.

In the obtained image, slight capri was observed, and Example 1
The resolution is lower.

Comparative Example 2 30 parts by weight of resin b, styrene-n-butyl acrylate-divinylbenzene crosslinked polymer (gel fraction 6α3%)
? Qi parts, and carbon black (same as Example 1) 5X! A portion of the mixture was melt blended, cooled, coarsely pulverized, and further finely pulverized using a jet mill to produce a toner having an average particle size of about 13 to 15 microns. This is a blend of the same gel content as in Example 2.

Four parts by weight of this toner were mixed with 96 il parts of iron powder carrier having an average particle size of about 50-80 microns to form a developer, which was used to obtain copies.

In the plasticizer resistance test, slight transfer is observed.

The fixing temperature range was from 170°C to 230°C.

The obtained image showed slight fogging, which was compared to Example 2.
The resolution is lower.

(Effects of the Invention) The method for producing a resin for toner of the present invention has the above-described configuration, and according to the present invention, it has excellent offset resistance, a wide range of fixing humidity, and has good plasticity resistance, blocking resistance, A toner resin that provides a toner with good image properties can be obtained.

Claims (1)

[Claims] 1. For toner, characterized in that a mixed solution of a linear polymer (a), a polymerizable monomer (b), and a crosslinking agent (c) is polymerized to obtain a resin having a gel content. Method of manufacturing resin. 2. The method for producing a toner resin according to item 1, wherein the linear polymer (a) is a copolymer having a styrene monomer and an acrylic acid or methacrylic acid ester monomer as constituent units. 3. The method for producing a resin for a toner according to item 1, wherein the gel component is a copolymer whose constituent units are a styrene monomer, an acrylic acid or methacrylic acid ester monomer, and a crosslinking agent. 4. The melt viscosity of the linear polymer at 160°C is 1 to 2.
,000 poise, the method for producing a toner resin according to any one of items 1 to 3. 5. Item 1 ~ where the gel content is about 5 to 60% by weight
4. The method for producing a resin for toner according to any one of item 4.