Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2001-05-31
2003-03-25
Chapman, Mark A. (Department: 1756)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C430S109100, C430S109300
Reexamination Certificate
active
06538063
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a toner used to develop an electrostatic latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method and the like, a binder resin used therein, and a resin composition which is a material thereof.
BACKGROUND OF THE INVENTION
In recent years, in order to attain coloration and energy saving in an electrophotographic copying machine or printer and the like, a low-temperature fixing-type toner has been developed. For achieving the low-temperature fixing, it is effective to decrease a heat-softening temperature of a toner resin. Generally, however, when a heat-softening temperature of a resin is decreased, a glass transition temperature of the toner is decreased at the same time. Accordingly, so-called toner blocking by which a toner forms a block in a storage state tends to occur, for which the fixing temperature cannot be decreased as desired.
In order to meet contradictory requirements of both the low-temperature fixability and the anti-blocking property, for example, Japanese Patent Laid-Open No. 1,952/1981 proposes a method using a polyester resin of which the fixing temperature is low though the affinity for paper is high and the heat-softening temperature and the glass transition temperature are high. In this case, although the low-temperature fixability and the anti-blocking property are improved to some extent, both of the properties are not satisfied enough at the same time. Besides, a polyester resin involves a problem that since it has high cohesive energy density, pulverization becomes difficult in production of a toner.
Meanwhile, Japanese Patent Laid-Open No. 257,868/1992 proposes a toner using a petroleum resin excellent in melting property and low-temperature fixability. Further, Japanese Patent Laid-Open No. 278,658/1996 proposes a toner using a hydrogenated petroleum resin. In these toners using the petroleum resin and the hydrogenated petroleum resin, however, the heat-softening temperature is low despite the high glass transition temperature. Accordingly, the low-temperature fixability is excellent, but the resins themselves are brittle, and it is difficult to use these resins singly as a toner resin. Further, almost all of these petroleum resins are a resin in which an aliphatic unsaturated bond remains in more than 50% of a petroleum resin before hydrogenation, a resin obtained by polymerizing a C
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monomer unpurified or simply purified and a hydrogenated aromatic petroleum resin having a hydrogenation rate of less than 10%. For this reason, all of these resins are colored yellow to brown. When these are incorporated in amounts of more than 35% by weight, there is a problem that a binder resin is strongly colored and color reproducibility is not satisfactorily obtained for coloration and also for monochrome. Further, since an active double bond is oxidized with air and a hydrophilic group tends to occur, there was also a likelihood that electricity stability in storage of a toner becomes poor.
Moreover, some of the petroleum resins used in these documents have a high content of a volatile component, and there is a likelihood that an odor is given off by heating in fixation at approximately 150° C. which is a general fixing temperature. Therefore, there is also a problem that the proportion of the petroleum resin cannot be increased to a composition of more than 35% by weight at which the low-temperature fixability becomes good.
In addition, Japanese Patent Laid-Open Nos. 274,520/1998, 52,611/1999, 52,612/1999, 52,614/1999 and 52,615/1999 propose a binder resin using a petroleum resin good in low-temperature fixability and hue and free from an odor in fixation. These have excellent performance in practical use. However, the petroleum resins are themselves incompatible with a polystyrene resin incorporated to have a binder resin exhibit suitable mechanical strength (the binder resin is not too strong nor brittle). Accordingly, both the components are hardly kneaded with high uniformity, and transparency of the resulting composition is not satisfactory. When this is applied to a toner for coloration, there is a problem that color reproducibility of transmitted light is not satisfactory.
Moreover, the use of a resin composition obtained by incorporating a styrene-acrylic resin or a polyester resin in these petroleum resins has been also proposed. In this case, the low-temperature fixability and the grindability in the production of a toner were improved, but were not said to be satisfactory.
DISCLOSURE OF THE INVENTION
The invention aims to provide a toner excellent in low-temperature fixability, having mechanical strength capable of enduring practical use as a toner and low environmental dependence in charging a toner, free from an odor in fixation and excellent in transparency, a binder resin for obtaining the toner having such characteristics and a resin composition which is a material thereof.
The invention includes the following first invention, second invention and third invention.
That is, the gist of the first invention is as follows.
[1] A resin composition comprising a resin (component A) obtained by polymerizing at least one monomer selected from cyclopentadiene, dicyclopentadiene and dihydrodicyclopentadiene and a styrene resin (component B) in which a content of a structural unit derived from styrene is 70% by weight or more.
[2] A toner binder resin for development of an electrostatically charged image using a resin composition comprising a resin (component A) obtained by polymerizing at least one monomer selected from cyclopentadiene, dicyclopentadiene and dihydrodicyclopentadiene and a styrene resin (component B) in which a content of a structural unit derived from styrene is 70% by weight or more.
[3] A toner binder resin for development of an electrostatically charged image using a resin composition in which component A is a resin obtained by subjecting at least one monomer selected from cyclopentadiene, dicyclopentadiene and dihydrodicyclopentadiene to cationic polymerization, heat polymerization or radical polymerization and/or a resin obtained by hydrogenating a part or the whole of a carbon-carbon unsaturated bond and/or an aromatic ring of these copolymers and component B is a styrene resin in which a content of a structural unit derived from styrene is 70% by weight or more and which has a weight-average molecular weight of 15,000 to 1,000,000 and a number-average molecular weight of 1,400 to 300,000.
[4] A toner binder resin for development of an electrostatically charged image using a resin composition in which component A is a copolymer resin obtained by copolymerizing (a) at least one monomer selected from cyclopentadiene, dicyclopentadiene and dihydrodicyclopentadiene and (b) at least one aromatic vinyl compound selected from styrene, &agr;-methylstyrene, vinyltoluene, isopropenyltoluene, indene, alkyl-substituted indene, allylbenzene, allyltoluene, tert-butylstyrene and tert-butylallylbenzene and/or a resin obtained by hydrogenating a part or the whole of a carbon-carbon unsaturated bond and/or an aromatic ring of these copolymer resins and component B is a styrene resin in which a content of a structural unit derived from styrene is 70% by weight or more and which has a weight-average molecular weight of 15,000 to 1,000,000 and a number-average molecular weight of 1,400 to 300,000.
[5] A toner binder resin for development of an electrostatically charged image using a resin composition in which component A is a copolymer resin obtained by copolymerizing (a) at least one monomer selected from cyclopentadiene, dicyclopentadiene and dihydrodicyclopentadiene and (c) at least one conjugated diolefin selected from isoprene, butadiene and 1,3-pentadiene and/or a resin obtained by hydrogenating a part or the whole of a carbon-carbon unsaturated bond and/or an aromatic ring of these copolymer resins and component B is a styrene resin in which a content of a structural unit derived f
Hikosaka Takaaki
Matono Kouichi
Shikuma Haruo
Tamura Hiroyuki
Chapman Mark A.
Idemitsu Kosan Co. Ltd.
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