Abstract: A binder for toner comprising a styrene/(meth)acrylate copolymer obtained by polymerizing polymerizable vinyl monomers comprising styrene and/or its derivative and a (meth)acrylate by suspension polymerization of 0.001-3 wt. %, based on the total weight of the monomers used, of at least one polyvinyl alcohol having a degree of saponification of 75-98% and 1.0-10 wt. %, based on the total weight of the monomers used, of at least one azo initiator. According to the present invention, there is provided a binder for a toner which produces copied images having excellent stability of image quality (life) even after a large number of times of copying.

Abstract: A process for producing a toner resin by a two-step suspension polymerization process, which entails preparing a polymer of high molecular weight having a weight average molecular weight of greater than about 350,000 from at least one monomer having a polymerizable vinyl group using a compound having at least three t-butyl peroxide groups in one molecule, as a polymerization initiator, and then preparing a low molecular weight polymer in the presence of the high molecular weight polymer. A toner having an excellent fixing property and offset resistance can be obtained from the above resin.

Abstract: A polyester resin comprised of (a) units derived from a terephthalic acid component and/or a isophthalic acid component, (b) 0 to 80 mole %, based on the total carboxylic acid component, of units derived from a diol component represented by the formula: ##STR1## wherein R represents an alkyl group having 2 or 3 carbon atoms, and x and y are integers satisfying the requirement of 2.ltoreq.x+y.ltoreq.6,and (c) 20 to 200 mole %, based on the total carboxylic acid component, of units derived from an aliphatic diol component. The polyester has a weight average molecular weight M.sub.w of 3,000 to 20,000, a number average molecular weight M.sub.n of 1,000 to 10,000, a glass transition temperature T.sub.g of 40.degree. to 70.degree. C., and a softening temperature of 70.degree. to 130.degree. C. The polyester is valuable for a toner.

Abstract: A process for producing a toner resin by a two-step suspension polymerization process, which entails preparing a polymer of high molecular weight having a weight average molecular weight of greater than about 350,000 from at least one monomer having a polymerizable vinyl group using a compound having at least three t-butyl peroxide groups in one molecule, as a polymerization initiator, and then preparing a low molecular weight polymer in the presence of the high molecular weight polymer. A toner having an excellent fixing property and offset resistance can be obtained from the above resin.

Abstract: Disclosed is a crosslinked polyester resin comprised of, based on the total acid units, (a) 1 to 30 mole % of units of a trihydric or higher alcohol or units of a trivalent or higher carboxylic acid, (b) 1 to 60 mole % of units of an alicyclic diol in which at least one alcohol component is a secondary alcohol, (c) 40 to 100 mole % of units of an aromatic dicarboxylic acid and (d) 40 to 99 mole % of units of a non-alicyclic diol, wherein the acid value is 0.5 to 25 mg-KOH/g, the glass transition temperature is 50.degree. to 80.degree. C., the softening temperature is not higher than 145.degree. C., the fixing-possible temperature covers a range of at least 30.degree. C., and the difference between the softening temperature and the glass transition temperature is not larger than 75.degree. C. The crosslinked polyester is used for toner for electrostatic recording.

Abstract: A resin for toner containing fine particles with a particle size passing through a 200 mesh sieve of not greater than 10% by weight.

Abstract: A process for the preparation of a toner polymer which comprises the steps of carrying out suspension polymerization of a monomer having a polymerizable vinyl group in the presence of polyvinyl alcohol as a dispersant, and then conducting oxidative decomposition of polyvinyl alcohol anchored to polymer particles obtained by suspension polymerization.

Abstract: A polyester resin for toner, which consists essentially of (a) from 0.5 to 50 mol %, based on the entire alcohol components, of at least one trihydric or higher polyhydric alcohol, (b) from 50 to 99.5 mol %, based on the entire alcohol components, of at least one diol and (c) at least one member selected from the group consisting of dicarboxylic acids and lower alkyl esters thereof, and which has a softening temperature of from 90.degree. to 170.degree. C., a glass transition temperature (Tg) of from 30.degree. to 70.degree. C., an acid value of from 0.5 to 15 mgKOH/g and a gel content of from 1.5 to 40%.

Abstract: Disclosed is a crosslinked polyester for a toner, which has an acid value of 5 to 20 mgKOH/g, a flow index of 0.1.times.10.sup.-4 to 300.times.10.sup.-4 ml/sec and a softening point lower than 145.degree. C., the polyester being formed by mixing a dicarboxylic acid component, a diol component and at least one crosslinking component selected from a polyfunctional carboxylic acid component having a trivalency or a higher valency and a polyhydric alcohol component having a trivalency or a higher valency at a mixing ratio represented by the following formula (1), reacting the mixture at a reaction ratio represented by the following formula (2) and subjecting the esterification product to polycondensation and crosslinking.0.8.ltoreq.R.ltoreq.1+5a (1)0.7.ltoreq.P.ltoreq.[R/(1+a)].sup.

Abstract: A polymer binder, in which the content of a residual monomer is not more than 200 ppm, generates a smell only to a very slight extent and provides a toner having an improved blocking resistance and resistance against a plasticizer for polyvinyl chloride. The polymer binder is prepared by maintaining a polymer suspension obtained by suspension polymerization at a temperature of not lower than the glass transition temperature of the polymer and distilling water in an amount of 5 to 60% by weight based on the amount of water present at the time of termination of the polymerization.

Abstract: A polyester resin for toner, which consists essentially of (a) from 0.5 to 50 mol %, based on the entire alcohol components, of at least one trihydric or higher polyhydric alcohol, (b) from 50 to 99.5 mol %, based on the entire alcohol components, of at least one diol and (c) at least one member selected from the group consisting of dicarboxylic acids and lower alkyl esters thereof, and which has a softening temperature of from 90.degree. to 170.degree. C., a glass transition temperature (Tg) of from 30.degree. to 70.degree. C., an acid value of from 0.5 to 15 mgKOH/g and a gel content of from 1.5 to 40%.

Abstract: A polyester resin for toner, which consists essentially of (a) from 5 to 60 equivalent %, based on the entire carboxylic acid components, of at least one member selected from the group consisting of tribasic and higher polybasic carboxylic acids, anhydrides thereof and lower alkyl esters thereof, (b) at least one member selected from the group consisting of dicarboxylic acids and lower alkyl esters thereof, (c) at least one aromatic diol and (d) at least one aliphatic diol, and which has a softening temeprature of from 100.degree. to 170.degree. C., a glass transition temperature (Tg) of from 50.degree. to 70.degree. C., an acid value of from 0.5 to 10 mgKOH/g and a gel content of from 3 to 40%.