JPH10232505A - Releasing agent for toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the anti-hot-offsetting property and preservability of a toner and to also improve the low-temp. fixability of the toner without deteriorating the flowability by using a releasing agent for a toner made of a specified ketone compd. SOLUTION: A releasing agent for a toner made of a keotne compd. represented by the formula is used. In the formula, each of R1 and R2 is aliphatic or arom. hydrocarbon and the total number of the C atoms of R1 and R2 is 16-90. The ketone compd. usually has 50-110 deg.C m.p. Since the ketone compd. is a relatively hard solid at room temp., a toner contg. the compd. is excellent in preservability and flowability. Since the compd. rapidly melts and becomes liq. when heated to >=50 deg.C, it is excellent in fixing temp. reducing effect and ensures superior anti-offsetting property. The releasing agent may be used in combination with other releasing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a release agent for electrophotographic toner. More specifically, the present invention relates to a release agent for toner having excellent low-temperature fixability, hot offset resistance, storage stability, and fluidity used in a heat fixing type copying machine or printer.

[0002]

2. Description of the Related Art In an electrophotographic process using a powdery dry toner, a contact heating type fixing device (a method using a heat roll, a method using a heat roll and a paper) is used to fix toner transferred onto paper or the like. Through a film or a belt (for example, JP-A-4-70688 and JP-A-4-70688).
No. 12558)) has been widely adopted. In this method, it is desirable that the temperature at which offset to the heat roll surface, film or belt occurs at a low temperature (hereinafter referred to as COT) is low, and the offset to the heat roll surface, film or belt at a high temperature is low. It is desirable that the temperature at which the heat generation occurs (hereinafter abbreviated as HOT) is high.
In order to obtain suitable COT and HOT, many methods have been proposed for widening the molecular weight distribution of the binder resin (for example, JP-A-61-215558). It is known that adding a low molecular weight polypropylene resin is effective. (For example, Japanese Patent Publication No. 52-3304)

[0003]

However, in response to recent demands for higher copy speed and lower energy fixing, there is a demand for fixing toner at a lower temperature. There is a need to lower it. For this purpose, it is effective to lower the molecular weight of the low molecular weight polypropylene-based resin to lower the melting point, but on the other hand, the fluidity of the toner is reduced, and the amount of the filmed material attached to the carrier is increased. There are problems such as. Alternatively, use of a natural wax such as carnauba wax (JP-A-4-362953), fatty acid ester,
Use of synthetic wax such as fatty acid amide (JP-A-56-1
44436) has been proposed. Although these have a low melting point, natural waxes such as carnauba wax have problems such as price and quality stability, and synthetic waxes such as fatty acid esters and fatty acid amides have problems such as poor toner storability.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies on a release agent for toner which does not have the above-mentioned drawbacks and exhibits excellent COT and HOT, and has reached the present invention. That is, the present invention is a toner release agent comprising a ketone compound represented by the following general formula (1). [Wherein, R1 and R2 are aliphatic or aromatic hydrocarbons, and the total carbon number of R1 and R2 is 16 to 90.] ]

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the general formula (1), R1 and R2 are aliphatic or aromatic hydrocarbons, and the total carbon number of R1 and R2 is usually 16 to 90.
, Preferably 20 to 90, more preferably 30
~ 90. If the total number of carbon atoms is less than 16, the melting point is low and the storage stability is poor. On the other hand, if the total carbon number exceeds 90, the compatibility with the toner binder deteriorates, the toner falls off during toner pulverization, and the low-temperature fixability deteriorates. As the aliphatic hydrocarbon group, an alkyl group having 1 to 50 carbon atoms,
50 alkenyl groups, specific examples of which include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, (iso) octyl, nonyl, (iso) decyl, dodecyl, Hexadecyl group,
Heptadecyl, octadecyl, docosyl, octacosyl, hexatriacontyl, hexatriacontyl, hexatetracontyl, butenyl, pentenyl, hexenyl, octenyl, nonenyl, dodecenyl, octadecenyl , A docosenyl group, an octacosenyl group and the like. Examples of the aromatic hydrocarbon group include a phenyl group and an alkylphenyl group having an alkyl group having 1 to 50 carbon atoms. Specific examples include a methylphenyl group, an ethylphenyl group, a propylphenyl group, a butylphenyl group, a pentylphenyl group, (Iso) hexylphenyl group, heptylphenyl group, (iso) octylphenyl group, nonylphenyl group, decylphenyl group, octadecylphenyl group and the like. Among them, those preferred as R1 are linear alkyl groups having 1 to 50 carbon atoms, and those preferred as R2 are linear alkyl groups having 1 to 50 carbon atoms, phenyl groups or linear alkyl groups having 1 to 50 carbon atoms. Is an alkylphenyl group having Examples of ketone compounds include methyl tricosyl ketone, pentyl octadecyl ketone, hexadecyl heptadecyl ketone,
Diheptadecyl ketone, hexenyl tridecyl ketone,
Octenyl tridecyl ketone, decyl tridecyl ketone, phenyl heptadecyl ketone, 3-methylphenyl heptadecyl ketone, 3-ethylphenyl stearoyl ketone and the like can be mentioned.

The ketone compound represented by the general formula (1) usually has a melting point of 50 to 110 ° C. For this reason, when used as a toner release agent, it is a relatively hard solid at room temperature, so it has excellent storage stability and fluidity during toner storage,
When heated to 50 ° C. or more, it quickly melts and becomes a liquid, so that it has an extremely excellent effect of lowering the fixing temperature and exhibits excellent hot offset resistance.

The release agent for ketone toners of the present invention can be used alone or in combination with other release agents.
Other release agents used in combination include polyolefin resins, fatty acid metal salts, fatty acid esters, fatty acid amides, alkylene bis fatty acid amides, esters of polyhydric alcohols, higher fatty acids, higher alcohols, paraffin waxes, hydrocarbon waxes, Fischer-Tropsch waxes. , Carnauba wax, montan wax and the like. Preferably a polyolefin resin having a number average molecular weight of 2,000 to 10,000, more preferably polypropylene,
Ethylene propylene copolymer and polyethylene.

The release agent for a ketone toner of the present invention can be used in addition to other components such as a toner binder at the time of toner production, or can be used in a form kneaded and mixed with the toner binder in advance. Examples of the toner binder include styrene-based resins, polyester-based resins, and composites thereof.

Examples of the styrene resin include a monofunctional styrene monomer, a (meth) acrylic monomer, and a resin obtained by polymerizing another monofunctional or polyfunctional monomer, if necessary, using a polymerization initiator. .

Examples of the styrene monomer include styrene and alkylstyrene (for example, α-methylstyrene, P-methylstyrene). Of these, styrene is preferred.

As the (meth) acrylic monomer, an alkyl (meth) acrylate [alkyl having 1 to 1 carbon atoms]
8, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-
Ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, etc.), hydroxyl group-containing (meth) acrylate [hydroxylethyl (meth) acrylate, etc.], amino group-containing (meth) acrylate [dimethylaminoethyl (meth) Acrylate, diethylaminoethyl (meth) acrylate, etc.], a nitrile group-containing (meth) acrylic compound [acrylonitrile, etc.], (meth) acrylic acid, and the like. Of these, preferred are alkyl (meth) acrylate and nitrile group-containing (meth)
It is an acrylic compound, and particularly preferable alkyl (meth) acrylates are methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
Lauryl (meth) acrylate, (meth) acrylic acid and mixtures of two or more of these. Among the nitrile group-containing (meth) acrylic compounds, particularly preferred is acrylonitrile.

Examples of other monomers include vinyl esters (eg, vinyl acetate, vinyl propionate, etc.) and aliphatic hydrocarbon monomers (eg, butadiene). Polyfunctional monomers include divinylbenzene, divinyltoluene, ethylene glycol di (meth)
Examples thereof include acrylate, 1,6-hexanediol di (meth) acrylate, and di (meth) acrylate of an ethylene oxide adduct of bisphenol A. If polyfunctional monomers are used, preference is given to divinylbenzene and 1,6-hexanediol diacrylate.

The polymerization of the styrene resin exemplified above is
Usually, solution polymerization or suspension polymerization is performed, but solution polymerization is preferred. In the case of solution polymerization, the solvent may be an aromatic hydrocarbon solvent (toluene, xylene, etc.), a chlorine solvent (chloroform, carbon tetrachloride, ethylene dichloride, ethylene tetrachloride, etc.), an ether solvent, and two or more of these solvents. Of mixed solvents. The amount of the solvent used is usually 1,000% or less, preferably 40% or less, based on the total weight of the monomers.
0% or less. When the amount of the solvent used exceeds 1,000%, the production efficiency decreases.

A polymerization initiator is usually used for the polymerization,
Examples of the polymerization initiator include an azo initiator (azobisisobutyronitrile, azobisisovaleronitrile, etc.) and a peroxide initiator (benzoyl peroxide, lauroyl peroxide, di-tert.-butyl peroxide, tert.-butylcumyl peroxide, dicumyl peroxide, tert.-butylperoxybenzoate, 1,1-bis (tert.-butylperoxy) 3,3,5-trimethylcyclohexane and the like.

The polymerization reaction is usually carried out under an atmosphere of an inert gas such as nitrogen. The polymerization temperature is usually 50 to 250C, preferably 70 to 230C. When the temperature is lower than 50 ° C., the initiation ability of the polymerization initiator becomes low. If the temperature exceeds 250 ° C., the decomposition of the polymer becomes remarkable. The reaction time depends on other conditions, but is usually 1 to 50 hours, preferably 2 to 10 hours. If the reaction time is shorter than 1 hour, it is often difficult to control the reaction, and if it exceeds 50 hours, it is economically disadvantageous. The solvent used for the polymerization is removed after the polymerization.
The desolvation is performed under normal pressure or reduced pressure.

The weight average molecular weight of the styrenic resin according to the present invention is usually from 2,000 to 1,000,000, preferably from 3,000 to 400,000, and the Tg is usually from 40 to 80 ° C, preferably from 45 to 45 ° C. ７０70 ° C. If the Tg is lower than 40 ° C., the storage stability of the toner becomes poor, and if it exceeds 80 ° C., the MFT becomes high, and the toner cannot be put to practical use.

Examples of the polyester resin include, for example, polycondensates of a polyhydric alcohol and a polybasic acid. Polyhydric alcohols include (1) ethylene glycol, diethylene glycol,
Aliphatic glycols such as triethylene glycol, 1,2-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol and alkylene oxides thereof [ethylene oxide (hereinafter abbreviated as EO), propylene Oxides (hereinafter abbreviated as PO) and the like] (2) Hydroquinone, catechol, resorcinol, pyrogallol, bisphenols (bisphenol A, bisphenol F, bisphenol sulfone, etc.) and hydrogenated bisphenols and alkylene oxides (EO)
And / or PO) -added phenolic glycols (3) glycerin, trimethylolpropane, trimethylolethane, hexanetriol, pentaerythritol, diglycerin, α-methylglucoside, sorbitol, xylitol, mannitol, glucose, fructose And octahydric alcohols such as sucrose and alkylene oxide adducts thereof (4) alkanolamines (triethanolamine,
Tripropanolamine, etc.), alkylenediamine (C2-6) [ethylenediamine, hexamethylenediamine, etc.], polyalkylene (alkylene C2-C2)
6) polyamines [diethylenetriamine, triethylenetriamine, etc.], aromatic amines (aniline, phenylenediamine, diaminotoluene, xylylenediamine, methylenedianiline, diethyltolylenediamine, diphenyletherdiamine, etc.), alicyclic amines (isophoronediamine, Cyclohexylmethanediamine, cyclohexylenediamine, etc.), heterocyclic amines (piperazine, aminoethylpiperazine, etc.)
And the like, and an alkylene oxide (EO and / or PO) added to an amino group-containing polyhydric alcohol and a mixture of two or more thereof. Preferred among these are ethylene glycol, neopentyl glycol, bisphenols (especially bisphenol A) to which 2-3 mol of alkylene oxide has been added, and mixtures of two or more of these. Particularly preferred are bisphenol A And neopentyl glycol and a mixture of two or more of these alkylene oxides.

Examples of polybasic acids include (1) succinic acid, maleic acid, fumaric acid, itaconic acid, azelaic acid, mesaconic acid, citraconic acid, sebacic acid, glutaconic acid, adipic acid, malonic acid, phthalic acid, isophthalic acid, Dibasic acids such as terephthalic acid, cyclohexanedicarboxylic acid, octylsuccinic acid and dodecenylsuccinic acid (2) trimellitic acid, 1,2,4-cyclohexanedicarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4 -Butanetricarboxylic acid, 1,2,5-
Hexanetricarboxylic acid, 1,3-dicarboxyl-2
-Methyl-2-methylenecarboxypropane, pyromellitic acid, benzophenonetetracarboxylic acid, cyclopentadienetetracarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, etc. Examples include basic acids, anhydrides of these acids, lower alkyl esters, and the like. In addition, polymerized fatty acids such as dimer and trimer of linoleic acid can be used. Of these, succinic, maleic, fumaric,
Alkyl or alkenyl (4 to 18 carbon atoms) succinic acid represented by phthalic acid, isophthalic acid, terephthalic acid, octyl succinic acid and dodecenyl succinic acid are preferred. As the polyester resin exemplified above, a linear type resin is preferable, but a trivalent or higher alcohol such as trimethylolpropane and / or a trivalent or higher polybasic acid such as trimellitic acid may be used in a small amount (polyhydric alcohol and A branched type obtained by using usually 1 to 30 mol%, preferably 2 to 10 mol% in a polybasic acid can also be used. In addition to the polyhydric alcohol and the polybasic acid, an amide bond-containing polyester resin produced by using a small amount of polyamines such as hexamethylenediamine and methylenediamine may also be used as the polyester resin according to the present invention. it can.

The polyesterification reaction is carried out, if necessary, in the presence of an esterification catalyst (eg, zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate, tetrabutyl titanate, etc.) at an optional temperature of usually 150 to 250 ° C. be able to. The reaction is carried out under normal pressure or reduced pressure.
Further, the reaction can be performed in the presence or absence of an inert gas or a solvent (for example, toluene, xylene, or the like).

The Tg of the polyester resin is usually 40
-80 ° C, preferably 45-70 ° C.
If the Tg is lower than 40 ° C., the storage stability of the toner becomes poor, and if it exceeds 80 ° C., the MFT becomes high, and the toner cannot be put to practical use.

Examples of the composite system of a styrene resin and a polyester resin include: (1) a mixture of a styrene resin and a polyester resin uniformly. (2) A styrene monomer polymerized in the presence of a polyester resin. (3) Polymerized polyester resin in the presence of styrene resin. And the like. It is preferable to add a ketone release agent to the composite toner binder among these toner binders.

As an example of the formulation of an electrophotographic toner to be used as the toner release agent of the present invention, the toner binder is usually 50 to 95% and the release agent is usually 1 to 30% based on the weight of the toner. 5 to 10% of a coloring material (carbon black, iron black, benzidine yellow, quinacridone, rhodamine B, phthalocyanine, etc.) and usually 1 to 5% of a charge controlling agent (nigrosine, quaternary ammonium circle, etc.)
And a magnetic powder (a powder of a ferromagnetic metal such as iron, cobalt and nickel or a compound such as magnetite, hematite and ferrite) usually containing 0 to 50%.

As an example of the method for producing an electrophotographic toner, the components in the above-mentioned formulation and the above-mentioned various additives are dry-blended, then melt-kneaded, coarsely pulverized, and finely pulverized using a jet pulverizer. Finally, a method for producing a toner having a particle size of usually 5 to 20 microns by classification is mentioned.

This electrophotographic toner can be used as a developer for an electric latent image by mixing it with carrier particles such as iron powder, glass beads, nickel powder and ferrite, if necessary. Further, hydrophobic colloidal silica fine powder can be used to improve the fluidity of the powder. As a method for fixing the electrophotographic toner to a support (paper, polyester film, etc.), a known heat roll fixing method can be applied.

[0025]

The present invention will be further described with reference to the following examples, but the present invention is not limited by these examples.

Example 1 Using diheptadecyl ketone (manufactured by Nippon Kasei Co., Ltd.), an electrophotographic toner was produced by the following method, and an electrophotographic developer was produced. All parts are by weight. Toner production method Styrene / acrylate / acrylonitrile copolymer / polyester composite toner binder 100 parts (number average molecular weight: 4,000, weight average molecular weight: 200,000, glass transition point: 58 ° C.) diheptadecyl ketone (Nippon Kasei ( Co., Ltd.) 4 parts Carbon black MA-100 8 parts (Mitsubishi Kasei Kogyo Co., Ltd.) Aizen Spiron Black TRH 1 part (Hodogaya Chemical Industry Co., Ltd.) At 1
The mixture was kneaded at 30 ° C. × 70 rpm for 30 minutes, and the obtained kneaded product was finely pulverized with a jet mill PJM100 (manufactured by Nippon Pneumatic). Using an airflow classifier MDS (manufactured by Nippon Pneumatic Co., Ltd.), fine powder of 5 μm or less was cut from the finely pulverized material. To 50 parts of the obtained powder, 0.15 parts of Aerosil R972 (manufactured by Nippon Aerosil Co., Ltd.) was uniformly mixed to obtain a toner. Developer Preparation Method 30 parts of the above toner and 800 parts of an electrophotographic carrier iron powder (F-100 manufactured by Powdertech Co., Ltd.) were mixed to obtain an electrophotographic developer (1).

Example 2 Diheptadecyl ketone was converted to octadecanophenone (Ald
The developer (2) was obtained in the same manner as in Example 1.

Example 3 An electrophotographic developer (3) was obtained in the same manner as in Example 1 except that one part of low molecular weight polypropylene (number average molecular weight: 3000) was added in addition to diheptadecyl ketone.

Comparative Example 1 An electrophotographic developer (4) was obtained in the same manner as in Example 1 except that diheptadecyl ketone was changed to low molecular weight polypropylene (number average molecular weight: 3000).

Comparative Example 2 Diheptadecyl ketone was converted to 2 hexadecanone (Aldri)
ch)), and an electrophotographic developer (5) was obtained in the same manner as in Example 1.

Test Results Regarding the electrophotographic developers (1) to (5), a toner image was transferred onto paper using a commercial copying machine (AR-5030 manufactured by Sharp Corporation), and the transferred toner on the paper was externally applied. Using a fixing machine, a fixing test was performed at a speed of 10 sheets / minute of A4 paper. The test results are as shown in Table 1.

[0032]

[Table 1]

COT The temperature of the heat roller at which cold offset occurs. HOT Heat roller temperature at which hot offset occurs. Toner bulk density Measured using a powder tester manufactured by Hosokawa Micron Corporation. (The larger the value, the better the fluidity of the toner.) Toner Preservation After the toner was left at 50 ° C. for 8 hours, it was measured using a powder tester manufactured by Hosokawa Micron Corporation. (The smaller the value, the better the preservation.)

By using the release agent of the present invention, it is possible to obtain an electrophotographic developer having excellent low-temperature fixability, hot offset resistance, storage stability, and excellent toner fluidity.

[0035]

When the release agent of the present invention is used in an electrophotographic toner, not only is it excellent in hot offset resistance and storage stability, but also the flow of the toner which has been inevitable when a low molecular weight polypropylene is conventionally used. The low-temperature fixability can be drastically improved without lowering the property, and its usefulness is extremely high.

Claims (4)

[Claims] 1. A toner release agent comprising a ketone compound represented by the following general formula (1). [Wherein, R1 and R2 are aliphatic or aromatic hydrocarbons, and the total carbon number of R1 and R2 is 16 to 90.] ] 2. In the general formula (1), R1 has 1 carbon atom.
A linear alkyl group having a carbon number of 1 to 50;
Is a linear alkyl group, a phenyl group or an alkylphenyl group having a linear alkyl group having 1 to 50 carbon atoms;
The release agent for toner according to claim 1, wherein the total number of carbon atoms of 1 and R2 is 16 to 90. 3. A toner composition comprising the release agent for a toner according to claim 1 or 2, a toner binder, and a colorant. 4. Further, the number average molecular weight is from 2,000 to 1.
4. The toner composition according to claim 3, which comprises 000 low molecular weight polyolefin.