JPH11133668A - Toner binder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dry type toner excellent in any of heat resistant preservability, low temp. fixing property and hot offset resistance and particularly unnecessary to apply oil on a hot roll in the use for a full color copying machine by containing a polyester modified by urethane bond and a non- modified polyester in a polyester. SOLUTION: Relating to a toner binder composed of the polyester derived from a polycarboxylic acid and a polyol, the polyester contains the urethane bond-modified polyester (i) and the non-modified polyester (ii) and the ratio of (i) to (ii) is controlled to 5/95 to 40/60. As the urethane bond-modified polyester (i), a reactant of a polyester A having hydroxide group with a polyisocyanate C, a reactant of A and C with a polyol or the like is exemplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a toner binder for a dry toner used in electrophotography, electrostatic recording, electrostatic printing, and the like.

[0002]

2. Description of the Related Art Conventionally, styrene resins, dry toners used for electrophotography, electrostatic recording, electrostatic printing, and the like have been used.
A toner binder such as polyester is melt-kneaded with a coloring agent or the like, and finely pulverized. These dry toners are developed and transferred to paper or the like, and then fixed by heating and melting using a hot roll. At that time, if the temperature of the hot roll is too high, there is a problem (hot offset) that the toner is excessively melted and fused to the hot roll. On the other hand, if the temperature of the hot roll is too low, the toner does not melt sufficiently and the fixing becomes insufficient. From the viewpoint of energy saving and downsizing of apparatuses such as copying machines, toners having a higher hot offset generation temperature (hot offset resistance) and a lower fixing temperature (low temperature fixing property) are required. Further, it is necessary to have a heat-resistant storage property in which the toner does not block during storage and at ambient temperature in the apparatus. Particularly in full-color copying machines and full-color printers, since the gloss and color mixing of the image are required, the toner must have a lower melt viscosity, and a sharp-melt polyester toner binder is used. ing. Since hot offset is likely to occur in such a toner, silicone oil or the like is conventionally applied to a heat roll in a full-color device. However, the method of applying silicone oil to the heat roll requires an oil tank and an oil application device, and the device becomes complicated and large. It also causes deterioration of the heat roll and requires maintenance at regular intervals. Furthermore, copy paper, O
It is inevitable that oil adheres to films for HP (overhead projector), especially OHP
In this case, there is a problem that the color tone is deteriorated by the attached oil.

[0003] Among the above-mentioned problems, those which are compatible with heat resistance storage stability, low-temperature fixability and hot offset resistance are as follows.
A polyester-based toner binder partially cross-linked by using a polyfunctional monomer (JP-A-57-109825) and a toner binder obtained by urethane-forming a hydroxyl-terminated polyester (JP-B-7-101318) have been proposed. . In order to reduce the amount of oil applied to a hot roll for full-color printing, a toner prepared by granulating polyester fine particles and wax fine particles (JP-A-7-56)
No. 390) has been proposed.

[0004]

However, those disclosed in and do not satisfy both the requirements of heat-resistant storage stability, low-temperature fixability, and hot offset resistance, and have a glossiness especially for full color use. It cannot be used because it does not express. In addition, the toner disclosed in JP-A-2003-123456 aims at oil-less fixing for full color printing, but does not have sufficient low-temperature fixing property and hot offset property.

[0005]

Means for Solving the Problems The present inventors have developed a toner binder which gives a dry toner excellent in all of heat resistance storage stability, low temperature fixability and hot offset resistance, especially when used in a full color copying machine or the like. As a result of intensive studies to develop a toner binder that provides a dry toner that has excellent gloss of an image and does not require oil application to a hot roll, the present invention has been achieved. That is, the present invention relates to a toner binder comprising a polyester derived from a polycarboxylic acid (a) and a polyol (b), wherein the polyester is modified with a urethane bond (i) and the unmodified polyester (ii) And the weight ratio of (i) to (ii) is from 5/95 to 40/60.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. Examples of the polyester (i) modified with a urethane bond include a reaction product of a polyester (A) having a hydroxyl group and a polyisocyanate (C), or a reaction product of (A) and (C) with a polyol (B). No. The polyester (A) having a hydroxyl group is a polycondensate of a polycarboxylic acid (a) and a polyol (b), and uses an excess of the number of equivalents of the hydroxyl group in (b) over the carboxyl group in (a). And the like. The number of hydroxyl groups contained in one molecule of the polyester having a hydroxyl group is usually 1 or more, preferably 1.5 to 3 on average, and more preferably 1.8 to 2.5 on average. With less than one per molecule,
The molecular weight of the urethane-modified polyester decreases, and the hot offset resistance deteriorates.

The polycarboxylic acid (a) includes dicarboxylic acid (a-1) and trivalent or higher polycarboxylic acid (a-
2), and (a-1) alone and a mixture of (a-1) and a small amount of (a-2) are preferable. Examples of the dicarboxylic acids (a-1) include alkylenedicarboxylic acids (succinic acid, adipic acid, sebacic acid, dodecenyl succinic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid). , Terephthalic acid, naphthalenedicarboxylic acid, etc.). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and 8 to 15 carbon atoms.
20 aromatic dicarboxylic acids. Examples of the trivalent or higher polycarboxylic acid (a-2) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid).
And the like. As the polycarboxylic acid (a), the above-mentioned acid anhydrides or lower alkyl esters (eg, methyl ester, ethyl ester, isopropyl ester) may be used.

The polyol (b) includes diol (b)
-1) and a trivalent or higher polyol (b-2), and (b-1) alone or (b-1) and a small amount of (b-
Mixtures of 2) are preferred. As the diol (b-1), alkylene glycol (ethylene glycol, 1,
2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc .; alkylene ether glycols (diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetra) Alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.); alkylene oxides of the above alicyclic diols (ethylene Oxides, propylene oxide, butylene oxide, etc.) adducts; alkylene oxides of the above bisphenols (ethylene oxide, propylene oxide, butyl oxide) Adducts and the like. Of these, preferred are those having 2 carbon atoms.
~ 12 alkylene glycol and alkylene oxide adducts of bisphenols, particularly preferred are alkylene oxide adducts of bisphenols,
And a combination thereof with an alkylene glycol having 2 to 12 carbon atoms. Examples of the trivalent or higher valent polyol (b-2) include trivalent or higher valent or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trivalent or higher phenols (Trisphenol P
A, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

Polyol (b) and polycarboxylic acid (a)
Is usually 2/1 to 1/1, as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH].
1, preferably 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

Also, a polyester having a hydroxyl group (A)
When reacting with the polyisocyanate (C), the polyol (B) can be used in combination. It is more preferable to use the polyol (B) in combination, since the hot offset resistance is improved. Examples of the polyol (B) include those similar to (b) which is a component of the polyester. Of these, preferred are those having 2 to 1 carbon atoms.
2 alkylene glycol and alkylene oxide adducts of bisphenols. The ratio of the polyester [OHA] having a hydroxyl group to the polyol [OHB] is usually 1/0 to 1 as an equivalent ratio [OHA] / [OHB] of the hydroxyl group.
/ 5, preferably 1-0 to 1/3, more preferably 1
/0.5 to 1/3. Further, for the purpose of adjusting the molecular weight of the urethane-modified polyester, a monool may be partially used in combination. Monools include alkyl alcohols (methanol, ethanol, butanol, octanol, lauryl alcohol, stearyl alcohol, etc.); alkyl alcohols (benzyl alcohol, etc.); alkylene oxide adducts of phenols (ethylene oxide adducts of phenol, nonylphenol Ethylene oxide adduct) and the like.

Examples of the polyisocyanate (C) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.). Aromatic diisocyanates (such as tolylene diisocyanate and diphenylmethane diisocyanate); araliphatic diisocyanates (such as α, α, α ′, α′-tetramethylxylylene diisocyanate); isocyanurates; , Caprolactam and the like; and combinations of two or more of these.

The ratio of the polyisocyanate (C) is the equivalent ratio [NC] of the total [OH] of the isocyanate group [NCO] and the polyester (A) having a hydroxyl group and the polyol (B).
[O] / [OH] is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, and more preferably 1.2 / 1.
１ ／ 1 / 1.2. When [NCO] / [OH] is more than 2 or less than 1/2, the molecular weight of the urethane-modified polyester becomes low, and the hot offset resistance deteriorates. The content of the polyisocyanate (C) component in the urethane-modified polyester is usually 0.2 to 30% by weight, preferably 0.5 to 20% by weight, and more preferably 1 to 15% by weight.
It is. If the content is less than 0.2% by weight, the hot offset resistance deteriorates, and the heat storage stability and the low-temperature fixability are disadvantageous. On the other hand, if it exceeds 30% by weight, the low-temperature fixability deteriorates.

The urethane-modified polyester of the present invention (i)
Is manufactured by a one-shot method or a prepolymer method. The weight average molecular weight of the urethane-modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number-average molecular weight of the urethane-modified polyester (i) is not particularly limited, and may be a number-average molecular weight that is easily obtained to obtain the weight-average molecular weight.

As the unmodified polyester (ii) constituting the toner binder together with the polyester (i) modified by the urethane bond, the same polycarboxylic acid (a) and polyol ( and polycondensates with b). Preferred (a) and (b) used are the same as (i). It is preferable that (i) and (ii) are at least partially compatible with each other in view of low-temperature fixability and hot offset resistance. Therefore,
The polyester component (i) and (ii) preferably have similar compositions. The weight ratio of (i) and (ii) is usually 5/95 to 40
/ 60, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, particularly preferably 7/93.
２０20/80. When the weight ratio of (i) is less than 5%,
The hot offset resistance is deteriorated, and it is disadvantageous in terms of compatibility between heat storage stability and low-temperature fixability. If it exceeds 40%, the low-temperature fixability and the gloss when used in a full-color device deteriorate.

The peak molecular weight of (ii) is usually from 1,000 to
It is 10,000, preferably 1500 to 10000, and more preferably 2000 to 8000. If it is less than 1,000, the heat-resistant preservability deteriorates, and if it exceeds 10,000, the low-temperature fixability deteriorates. The hydroxyl value of (ii) is usually 5 or more,
Preferably 10 to 120, more preferably 20 to 80
It is. If it is less than 5, it is disadvantageous in terms of compatibility between heat-resistant storage stability and low-temperature fixability. The acid value of (ii) is usually 0 to 120, preferably 0 to 50, and more preferably 5 to 30. By giving an acid value, the negative charge property is improved, and thus it is preferable when a charge control agent is not used in a negative charge toner.

The glass transition point (Tg) of the toner binder of the present invention is usually 35 to 85 ° C., preferably 45 to 70 ° C.
It is. If the temperature is lower than 35 ° C., the heat storage stability of the toner deteriorates,
If the temperature exceeds 85 ° C., the low-temperature fixability becomes insufficient. The storage elastic modulus (G ′) of the toner binder is measured frequency 2
The temperature (TG ′) at which 10000 dyne / cm 2 at 0 Hz is usually 100 ° C. or more, preferably 110 to
200 ° C. If the temperature is lower than 100 ° C., the hot offset resistance deteriorates. As the viscosity of the toner binder, the temperature (T
η) is usually 180 ° C or lower, preferably 90 to 160 ° C.
It is. If it exceeds 180 ° C., the low-temperature fixability deteriorates. That is, TG ′ is preferably higher than Tη from the viewpoint of achieving both low-temperature fixability and hot offset resistance. In other words, the difference between TG ′ and Tη (TG′−Tη) is preferably 0 ° C. or more. It is more preferably at least 10 ° C, particularly preferably at least 20 ° C. The upper limit is not particularly limited.
Further, from the viewpoint of achieving both heat-resistant storage stability and low-temperature fixability, Tη
And the difference between Tg is preferably 0 to 100 ° C. The temperature is more preferably from 10 to 90 ° C, particularly preferably from 20 to 80 ° C.

Specific examples of the toner binder of the present invention include the following. Mixture of a polyester obtained by urethanizing a polycondensate of bisphenol A ethylene oxide 2 mol adduct and isophthalic acid with isophorone diisocyanate, and a polycondensate of bisphenol A ethylene oxide 2 mol adduct and isophthalic acid 2 mol of bisphenol A ethylene oxide Of a polyester obtained by urethanizing a polycondensate of a product and isophthalic acid with isophorone diisocyanate, and a polycondensate of bisphenol A ethylene oxide 2 mol and terephthalic acid bisphenol A ethylene oxide 2 mol adduct /
Polyester obtained by urethanizing a polycondensate of bisphenol A propylene oxide 2 mol adduct and terephthalic acid with isophorone diisocyanate, and a polycondensate of bisphenol A ethylene oxide 2 mol adduct / bisphenol A propylene oxide 2 mol adduct and terephthalic acid Mixture of bisphenol A ethylene oxide 2 mol adduct /
A mixture of a polyester obtained by urethanizing a polycondensate of bisphenol A propylene oxide 2 mol adduct and terephthalic acid with isophorone diisocyanate and a polycondensate of bisphenol A propylene oxide 2 mol adduct and terephthalic acid 2 mol bisphenol A ethylene oxide addition Of a polycondensate of terephthalic acid and a polycondensate of 1,4-butanediol with isophorone diisocyanate, and a polycondensate of terephthalic acid with 2 mol of bisphenol A ethylene oxide adduct bisphenol A ethylene oxide 2 Polycondensate of terephthalic acid and 1,4-butanediol with urethanized isophorone diisocyanate; bisphenol A ethylene oxide 2 moles adduct Mixture of 2-mol adduct of propylene oxide and polycondensate of terephthalic acid Bisphenol A ethylene oxide 2-mol polycondensate of terephthalic acid and 2-mol adduct of bisphenol A ethylene oxide are urethanized with isophorone diisocyanate Polyester and bisphenol A
Mixture of polycondensate of ethylene oxide 2 mol adduct and terephthalic acid Polyester obtained by urethanizing polycondensate of bisphenol A ethylene oxide 2 mol adduct and isophthalic acid with diphenylmethane diisocyanate, and bisphenol A ethylene oxide 2 mol adduct Mixture of isophthalic acid with polycondensate Bisphenol A ethylene oxide 2 mol adduct /
A polyester obtained by urethanizing a polycondensate of bisphenol A propylene oxide 2 mol adduct and terephthalic acid / dodecenyl succinic anhydride with diphenylmethane diisocyanate, and bisphenol A ethylene oxide 2
Molar adduct / bisphenol A propylene oxide 2
A mixture of a molar addition product and a polycondensate of terephthalic acid (10) a polyester obtained by urethane-forming a 2-condensation product of bisphenol A ethylene oxide 2 mol adduct and terephthalic acid, and 1,4-butanediol with diphenylmethane diisocyanate; Mixture of bisphenol A ethylene oxide 2 mol adduct and terephthalic acid polycondensate (11) Polyester of bisphenol A ethylene oxide 2 mol adduct and isophthalic acid polycondensate urethanized with toluene diisocyanate, bisphenol A ethylene oxide Mixture of 2 mol adduct and polycondensate of isophthalic acid (12) Polyester obtained by urethaneizing 2 mol adduct of bisphenol A ethylene oxide with terephthalic acid and 1,4-butanediol with toluene diisocyanate ,Screw Mixture of phenol A ethylene oxide 2 mol adduct and terephthalic acid polycondensate (13) Hexamethylene diisocyanate of bisphenol A ethylene oxide 2 mol adduct and terephthalic acid polycondensate and 1,4-butanediol Mixture of urethane-modified polyester, polycondensate of terephthalic acid with 2 mol of bisphenol A ethylene oxide

The toner binder of the present invention can be produced by the following method. The polyester (A) having a hydroxyl group comprises a polycarboxylic acid (a) and a polyol (b)
In the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide,
It is obtained by heating to 0 ° C. and performing dehydration condensation. It is also effective to reduce the pressure in order to improve the reaction rate at the end of the reaction. The polyester (i) modified with a urethane bond is obtained by reacting (A) and optionally used polyol (B) with polyisocyanate (C) at 50 to 140 ° C. At the time of the reaction, a solvent can be used if necessary. Examples of usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And the like (e.g., tetrahydrofuran), which are inert to the isocyanate (C). Unmodified polyester (ii) can be obtained in the same manner as polyester (A) having a hydroxyl group. The method of mixing (i) and (ii) includes (i) and (ii)
Are dissolved in a solvent in which they are soluble and mixed, and then the solvent is distilled off, and (i) and (ii) are melt-mixed using a kneading machine such as an extruder. If the temperature is increased during mixing, (i) and (ii)
Is exchanged, and the low-temperature fixing property and the hot offset resistance deteriorate. Therefore, the temperature during mixing is usually 17
The temperature is 0 ° C or lower, preferably 150 ° C or lower, more preferably 120 ° C or lower. In order to suppress the transesterification reaction, known transesterification inhibitors (such as alkyl phosphates) can also be used. In the mixing method using the solvent of, to easily evaporate the solvent at low temperature,
After dispersing the solvent solutions (i) and (ii) in water, the solvent can be distilled off from the aqueous dispersion. In this method, after distilling off the solvent, the toner binder is obtained by filtering, washing and drying the dispersion from water. Examples of the solvent that can be used include the same solvents as those that can be used in the urethanization reaction. A solvent having a boiling point of 100 ° C. or less is particularly preferable for easy distillation.

The toner binder of the present invention is used as a dry toner by mixing a colorant and, if necessary, various additives such as a release agent and a charge control agent. Known dyes, pigments, and magnetic powders can be used as the colorant. Specifically, carbon black, Sudan Black SM, Fast Yellow-G, Benzidine Yellow, Pigment Yellow, India First Orange, Irgasin Red, Baranitoaniline Red, Toluidine Red, Carmine FB, Pigment Orange R, Lake Red 2G, Rhodamine FB, Rhodamine B lake, Methyl Violet B lake, phthalocyanine blue, pigment blue, brilliant green, phthalocyanine green, oil yellow GG, Kayaset YG, Orazole Brown B, oil pink OP, magnetite, iron black and the like. The content of the colorant in the toner is usually 2 to 15% by weight.

Known release agents can be used, for example, polyolefin waxes (polyethylene wax, polypropylene wax, etc.); long-chain hydrocarbons (paraffin wax, sasol wax, etc.); carbonyl group-containing waxes, etc. Is mentioned. Preferred among these are carbonyl group-containing waxes. Examples of the carbonyl group-containing wax include polyalkanoic acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18 Polyalkanol esters (tristearyl trimellitate, distearyl maleate, etc.); polyalkanoic acid amides (ethylenediamine dibehenylamide, etc.); polyalkylamides (trimellitic acid, tristearylamide, etc.) And dialkyl ketones (such as distearyl ketone). Preferred among these carbonyl group-containing waxes are polyalkanoic esters. The content of the release agent in the toner is usually 0 to 40% by weight, preferably 1 to 30% by weight.

Examples of the charge controlling agent include known ones, that is, nigrosine dye, quaternary ammonium salt compound, quaternary ammonium base-containing polymer, metal-containing azo dye, salicylic acid metal salt, sulfonic acid group-containing polymer, fluorinated polymer, Examples include a halogen-substituted aromatic ring-containing polymer. The content of the charge control agent in the toner is usually 0 to 5% by weight. In addition, fluidizing agents can be used. Known fluidizers such as colloidal silica, alumina powder, titanium oxide powder, and calcium carbonate powder can be used.

As a method for producing a dry toner, a known kneading and pulverizing method can be used. After the above-mentioned toner components are dry-blended, they are melt-kneaded, then finely pulverized using a jet mill or the like, and further subjected to air classification to have a particle size of usually 2 to 2.
Obtained as 0 μm particles.

The dry toner using the toner binder of the present invention may contain iron powder, glass beads, nickel powder,
It is used as a developer for an electric latent image by being mixed with carrier particles such as ferrite, magnetite, and ferrite whose surface is coated with a resin (such as an acrylic resin or a silicone resin). In addition, instead of the carrier particles, friction with a member such as a charging blade can be performed to form an electric latent image. Next, the recording material is fixed on a support (paper, polyester film, or the like) by a known hot roll fixing method, flash fixing method, or the like.

[0025]

The present invention will be further described with reference to the following examples.
The present invention is not limited to this. Hereinafter, "part" indicates "part by weight".

Example 1 In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe,
Bisphenol A ethylene oxide 2 mol adduct 34
3 parts, 166 parts of isophthalic acid and 2 parts of dibutyltin oxide were added, reacted at 230 ° C. for 8 hours under normal pressure, and further reacted for 5 hours under reduced pressure of 10 to 15 mmHg.
C., and 17 parts of isophorone diisocyanate in methyl ethyl ketone (MEK) was reacted at 80.degree. C. for 8 hours to obtain a urethane-modified polyester (1) having a weight average molecular weight of 72,000. In the same manner as described above, 570 parts of a bisphenol A ethylene oxide 2 mol adduct and 217 parts of terephthalic acid are polycondensed at 230 ° C. for 6 hours under normal pressure to obtain an unmodified polyester having a peak molecular weight of 2400, a hydroxyl value of 51 and an acid value of 5 ( a) was obtained. 200 parts of the urethane-modified polyester (1) and 800 parts of the unmodified polyester (a) were mixed with ethyl acetate / MEK (1/1).
1) It was dissolved and mixed in 1000 parts to obtain an ethyl acetate / MEK solution of the toner binder (1). In a reaction vessel equipped with a cooling pipe, a stirrer and a thermometer, 942 parts of water and 58 parts of a 10% suspension of hydroxyapatite (Supertight 10 manufactured by Nippon Kagaku Kogyo Co., Ltd.) were put, and the toner binder ( 1000 parts of the ethyl acetate / MEK solution of 1) was added and dispersed. The temperature was raised to 98 ° C., and the organic solvent was distilled off. After cooling, the mixture was filtered from water, washed and dried to obtain the toner binder (1) of the present invention. T of toner binder (1)
g was 55 ° C., Tη was 128 ° C., and TG ′ was 140 ° C.

Example 2 A reaction was carried out in the same manner as in Example 1 except that the isocyanate was changed to 14 parts of toluene diisocyanate.
8,000 urethane-modified polyesters (2) were obtained. Similarly, 363 parts of bisphenol A ethylene oxide 2 mol adduct and 166 parts of isophthalic acid were polycondensed in the same manner as in Example 1 to obtain a peak molecular weight of 4,300, a hydroxyl value of 25, and an acid value of 7.
Unmodified polyester (b) was obtained. After dissolving 250 parts of the urethane-modified polyester (2) and 750 parts of the unmodified polyester (b) in the same manner as in Example 1, the solvent was removed to obtain the toner binder (2) of the present invention. Tg is 56 ° C., Tη is 135 ° C., TG ′ is 152 ° C.
Met.

Example 3 Bisphenol A ethylene oxide 2 mol adduct 34
After 3 parts and 166 parts of isophthalic acid were polycondensed in the same manner as in Example 1, 1,4 was added in methyl ethyl ketone (MEK).
7 parts of butanediol and 34 parts of isophorone diisocyanate were added and reacted at 80 ° C. for 8 hours to obtain a urethane-modified polyester (3) having a weight average molecular weight of 68,000. After dissolving 200 parts of the urethane-modified polyester (3) and 800 parts of the unmodified polyester (b) in the same manner as in Example 1, the solvent was removed to obtain the toner binder (3) of the present invention. Tg is 55 ° C, Tη is 129 ° C, TG '
Was 151 ° C.

Comparative Example 1 Bisphenol A ethylene oxide 2 mol adduct 35
4 parts and 166 parts of isophthalic acid were polycondensed in the same manner as in Example 1 to obtain a comparative toner binder (1) having a weight average molecular weight of 8,000. Tg of comparative toner binder (1)
Was 57 ° C., Tη was 136 ° C., and TG ′ was 133 ° C.

Comparative Example 2 Bisphenol A propylene oxide adduct 454
Parts, 140 parts of diethylene glycol and 398 parts of isophthalic acid were subjected to polycondensation in the same manner as in Example 1. Next, 48.5 parts of diphenylmethane diisocyanate and Example 1
And a urethane-modified polyester (4) having a weight average molecular weight of 77000 was obtained. 654 parts of bisphenol A propylene oxide adduct and terephthalic acid 4
42 parts were subjected to polycondensation under ordinary pressure at 230 ° C. for 20 hours to obtain an unmodified polyester (c) having a peak molecular weight of 3,000, a hydroxyl value of 2, and an acid value of 50. After dissolving 500 parts of the urethane-modified polyester (4) and 500 parts of the unmodified polyester (c) in the same manner as in Example 1, the solvent was removed to obtain a comparative toner binder (2). Tg is 57
° C, Tη was 165 ° C, and TG 'was 174 ° C.

Evaluation Examples 1 to 3 and Comparative Evaluation Examples 1 and 2 100 parts of the toner binder (1) to (3) of the present invention, 100 parts of the comparative toner binder (1) or (2), 7 parts of glycerin tribehenate and 4 parts of cyanine blue KRO (manufactured by Sanyo Dyeing Co., Ltd.) was converted into a toner by the following method. First, Henschel mixer (FM10B, manufactured by Mitsui Miike Kakoki Co., Ltd.)
After pre-mixing using a mixer, a twin-screw kneader (Ikegai Co., Ltd.
CM-30). Then, after crushing finely using a supersonic jet crusher LabJet (manufactured by Nippon Pneumatic Industries, Ltd.), an airflow classifier (Nippon Pneumatic Industries, Ltd.)
Classified by MDS-I) and the particle size d50 is 5 to 20μ.
m of toner particles were obtained. Then, 0.5 part of colloidal silica (Aerosil R972: manufactured by Nippon Aerosil) was mixed with 100 parts of the toner particles using a sample mill to obtain toners (1) to (3), comparative toners (1) and (2). .
Table 1 shows the evaluation results.

[0032]

[Table 1] ---------------------------------------------------------------------------- Toner No. Heat-resistant storage stability GLOSS HOT ----------------------------------- −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Toner (1) 31% 135 ° C. 165 ° C. Toner (2) 29% 145 190 ° C. Toner (3) 30% 140 ° C. 190 ° C. Comparative toner (1) 28% 150 ° C. 160 ° C. Comparative toner (2) 25% 230 ° C. or higher 230 ° C. or higher −−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−− [Evaluation method] Heat storage stability After storing the toner at 50 ° C. for 8 hours, sieve through a 42 mesh sieve for 2 minutes. The heat-resistant storage stability was defined as the residual ratio on the wire mesh. The residual ratio of toner having better heat resistance storage stability is smaller. Gloss development temperature (GLOSS) Fixing was evaluated using a modified machine in which the oil supply device was removed from the fixing device of a commercially available color copying machine (CLC-1; manufactured by Canon) and the oil on the fixing roll was removed. The gloss development temperature was defined as the fixing roll temperature at which the 60 ° gloss of the fixed image became 10% or more. Hot Offset Occurrence Temperature (HOT) The fixing was evaluated in the same manner as in the above GLOSS, and the presence or absence of hot offset to the fixed image was visually evaluated. The temperature of the fixing roll at which the hot offset occurred was defined as the hot offset occurrence temperature.

Example 4 300 parts of the urethane-modified polyester (3) and 700 parts of the unmodified polyester (b) were dissolved and desolvated in the same manner as in Example 1, to obtain a toner binder (4) of the present invention. . Tg is 57 ° C., Tη is 144 ° C., TG ′ is 165
° C.

Evaluation Example 4 and Comparative Evaluation Example 3 Toner binder (4) and comparative toner binder (2) were used as a releasing agent and a coloring agent, and montan wax W was used.
Except that 5 parts of E-40 (manufactured by Hoechst Japan) and 8 parts of carbon black (MA100 manufactured by Mitsubishi Chemical Corporation) were used, the toner (3) and the comparative toner (3) were prepared in the same manner as in Evaluation Example 1. Obtained. Table 2 shows the evaluation results.

[0035]

Table 2 ------------------------------------------------------------------------------ Toner No. Heat-resistant storage stability MFT HOT --------------------------------- −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Toner (4) 31% 125 ° C. 230 ° C. or higher Comparative toner (3) 30 % 155 ° C. 230 ° C. or more −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− [Evaluation method] Heat resistant storage toner Was stored at 50 ° C. for 8 hours, sieved through a 42-mesh sieve for 2 minutes, and the residual ratio on the wire net was taken as the heat-resistant storage stability. The residual ratio of toner having better heat resistance storage stability is smaller. Minimum Fixing Temperature (MFT) The fixing was evaluated using a commercially available black-and-white copying machine (SF8400A; manufactured by Sharp). The minimum fixing temperature was the fixing roll temperature at which the residual ratio of the image density after rubbing the fixed image with a pad was 70% or more. Hot offset occurrence temperature (HOT) The fixing was evaluated in the same manner as in the above MFT, and the presence or absence of hot offset to the fixed image was visually evaluated. The temperature of the fixing roll at which the hot offset occurred was defined as the hot offset occurrence temperature.

[0036]

The toner binder of the present invention has the following effects. 1. Excellent heat-resistant storage stability, and excellent both low-temperature fixability and hot offset resistance. 2. Since the color toner is excellent in glossiness and hot offset resistance, it is not necessary to apply oil to the fixing roll. 3. High transparency and excellent color tone when used as a color toner.

Claims (8)

[Claims] 1. A toner binder comprising a polyester derived from a polycarboxylic acid (a) and a polyol (b), wherein the polyester (i) modified with a urethane bond and the polyester (ii) not modified are used. And the weight ratio of (i) to (ii) is 5/9
5 to 40/60. 2. The peak molecular weight of (ii) is from 1,000 to 1,
1.00 and a hydroxyl value of 5 or more.
The toner binder as described in the above. 3. The method according to claim 1, wherein the polyol (b) is an alkylene oxide adduct of a bisphenol.
The toner binder as described in the above. 4. The (i) is a reaction product derived from a polyester (A) having a hydroxyl group, a polyol (B) and a polyisocyanate (C), and the ratio of (A) to (B) is: The equivalent ratio [OH _A ] / [OH _B ] of the hydroxyl group [OH _A ] of (A) and the hydroxyl group [OH _B ] of (B) is 1/0 to 0:
The toner binder according to any one of claims 1 to 3, which is 1/5. 5. The glass transition point (T) of the toner binder.
g) is 35 to 85 ° C., and the difference (TG′−) between the temperature (TG ′) at which the storage elastic modulus (G ′) at a measurement frequency of 20 Hz is 10,000 dyne / cm ² and the temperature (Tη) at which the viscosity is 1000 poise. The toner binder according to claim 1, wherein Tη) is 0 ° C. or higher. 6. The measuring frequency of the toner binder is 20H.
The difference (Tη−Tg) between the temperature (Tη) at which the viscosity at z becomes 1000 poise and the glass transition point (Tg) is 0 to 100.
The toner binder according to any one of claims 1 to 5, wherein the temperature is 0C. 7. The toner according to claim 1, which is used for a toner for heat fixing.
7. The toner binder according to any one of items 6 to 6. 8. The toner binder according to claim 1, which is used for a full-color toner.