JP2000267347A - Wax for electrophotographic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the wax for the electrophotographic toner good in compatibility with a toner resin and superior in offset resistance and transparence. SOLUTION: This wax is used as a releasing agent for the electrophotographic toner using a styrene-acrylic resin and/or a polyester resin as a fixing resin. It is composed essentially of a polar wax having at least one kind of releasing group among carbonyl, carboxyl, hydroxyl group, ester bond and epoxy bond of an amount of >=7 number % per one molecule of the polar wax, and the polar wax has a melting point 65-110 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release agent for an electrophotographic toner.

[0002]

2. Description of the Related Art Hitherto, in electrophotographic toners for copying machines and printers, there has been a demand for speeding up the copying machine and saving energy. In order to cope with this, development of toner having excellent low-temperature fixability has been demanded, and various studies have been made.

[0003] Among electrophotographic toners, a hot-roll fixing method has attracted attention as an effective fixing method because it has good thermal efficiency and can be fixed quickly. However, when an image is fixed by a heating roller or the like, a so-called offset phenomenon occurs in which a part of the electrostatic toner adheres to the heating body and stains the next copy sheet.

Conventionally, various methods have been studied to prevent such a phenomenon, and non-polar waxes such as petroleum wax, low molecular weight polyethylene wax, and low molecular weight polypropylene wax are added to impart releasability to the toner. A method is used. However, these non-polar wax-based release agents not only have a high melting point and are not compatible with lowering the energy of the toner, but also have poor compatibility with the styrene / acrylic resin and / or polyester resin and are uniformly dispersed in the resin. As a result, aggregation of the wax in the toner or uneven exposure of the wax to the toner surface occurs, and the offset phenomenon has not been completely eliminated. In addition, regarding transparency, which is regarded as important in color toners, there is a problem that non-polar wax-based release agents have poor dispersibility and hinder resin transparency.

Further, Japanese Patent Application Laid-Open Nos. 7-219274 and 9-2
As shown in 69609, the roller surface is impregnated with silicone oil or supplied with silicone oil to improve the transparency of the color toner and to eliminate the offset phenomenon. There was a problem that stickiness on paper and the apparatus became complicated and cost increased.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a wax for toner which has good compatibility with the resin for toner, and has excellent offset resistance and transparency.

[0007]

In view of the above-mentioned current situation of the toner, the present inventors have conducted various studies on toner waxes having excellent offset resistance and transparency, and as a result, have found that a styrene / acrylic resin and / or a polyester resin can be used for fixing. In an electrophotographic toner as a resin, at least one of a carbonyl group, a carboxyl group, a hydroxyl group, an ester bond, and a urethane bond in a hydrocarbon is used as a release agent at an average of at least 0.07 per molecule. It has been found that it is particularly effective to use a polar wax containing at least one and having a melting point of 65 to 110 ° C. as an essential component, and have completed the present invention.

Hereinafter, the present invention will be described in detail. The wax for a toner of the present invention contains at least 0.07 or more polar groups of at least one kind among polar groups in a hydrocarbon among carbonyl groups, carboxyl groups, hydroxyl groups, ester bonds, and urethane bonds on average, And melting point of 65 to 110
It is a polar wax that is in ° C. An average of 0.07 polar groups per molecule means that the wax has an acid value of 5.6 mgKOH / g, for example, when a hydrocarbon having an average molecular weight of 700 has only a carboxyl group. .
If the number of polar groups per molecule is less than 0.07 on average, the compatibility with the resin decreases, and the dispersibility deteriorates, which is not preferable. The melting point of the wax is 65-1.
10 ° C. is preferred. A wax having a melting point of less than 65 ° C. tends to cause thermal aggregation when blended in a toner, and has a problem in storage stability. On the other hand, a wax such as polypropylene or polyethylene having a melting point exceeding 110 ° C. requires a large amount of energy for melting the toner at the time of fixing and is not preferable because it goes against energy saving.

Specific examples of the wax of the present invention include:
Wax oxide obtained by air oxidation of petroleum wax or Fischer-Tropsch wax, petroleum wax, α-olefin wax having a double bond at a terminal,
Alcohol type wax obtained by air oxidation of any of Fischer-Tropsch wax in the presence of boric acid, urethane wax obtained by reacting the alcohol type wax with tolylene diisocyanate, an acid component of stearic acid or behenic acid and stearyl alcohol, Ethanol wax, benenyl alcohol, 1,4-butanediol obtained by reacting with any alcohol component, low melting point component of rice bran wax or carnauba wax is removed by solvent treatment or by using a falling or centrifugal thin film distillation apparatus. Ester wax obtained, ketone wax obtained by decarboxylation of stearic acid at high temperature under metal oxide catalyst, 3-pentadecyl phenol obtained by reacting chloroacetic acid with 3-pentadecyl phenol which is a hydrogenated product of cashew nut oil. Phenoxy include acetate.

More specifically, when the wax is a wax oxide obtained by air oxidation of petroleum wax or Fischer-Tropsch wax, the acid value is from 1 to 2
0 mgKOH / g, and the difference between the extrapolated melting start temperature and the melting peak temperature of the DSC measured at a heating rate of 5 ° C./min is 25.
Waxes that are within ° C are preferred. Acid value is 1mgKOH
If it is less than / g, the compatibility with the resin is reduced, and the dispersibility is deteriorated. On the other hand, the acid value is 20 mgK
If it exceeds OH / g, components having a low molecular weight and a low melting point generated by air oxidation increase, and when blended in a toner, thermal aggregation is liable to occur and there is a problem in storage stability. Also, DSC
The wax oxide having a difference between the extrapolation melting start temperature and the melting peak temperature of more than 25 ° C. is not preferable because it has many low-melting components and deteriorates the storage stability. In order to narrow the difference between the extrapolation melting start temperature and the melting peak temperature of the DSC, it is preferable to remove the low melting point component of the oxide by solvent treatment or by a falling or centrifugal thin film distillation apparatus.

When the wax is an alcohol type wax obtained by air oxidation of any of petroleum wax, α-olefin wax having a double bond at a terminal, and Fischer-Tropsch wax in the presence of boric acid, the hydroxyl value is 50 to 50. Waxes having a difference of 90 mg KOH / g and a difference between the extrapolative melting onset temperature of DSC and the melting peak temperature measured at a heating rate of 5 ° C./min within 25 ° C. are preferred. If the hydroxyl value is less than 50 mgKOH / g, the compatibility with the resin is reduced, and the dispersibility is deteriorated.
On the other hand, when the hydroxyl value exceeds 90 mgKOH / g, the low melting point component generated by air oxidation increases, and when blended in a toner, thermal aggregation is liable to occur and there is a problem in storage stability. Further, an alcohol type wax in which the difference between the extrapolation melting onset temperature of DSC and the melting peak temperature exceeds 25 ° C. is not preferable because the content of the low melting point component is large and the storage stability is reduced. D
In order to narrow the difference between the extrapolation melting start temperature and the melting peak temperature of SC, it is preferable to remove the low-melting-point component of the alcohol-type wax by solvent treatment or a flow-down or centrifugal thin-film distillation apparatus.

When the wax is a urethane wax obtained by reacting the alcohol type wax with tolylene diisocyanate, DSC measured at a heating rate of 5 ° C./min.
The wax whose difference between the extrapolation melting start temperature and the melting peak temperature is within 25 ° C. is preferred. If the temperature difference exceeds 25 ° C., it is not preferable because the storage stability decreases due to the low melting point component.
In order to narrow the difference between the extrapolation melting onset temperature of DSC and the melting peak temperature, it is preferable to remove the low melting point component of the urethane wax by solvent treatment or by a flow-down or centrifugal thin-film distillation apparatus.

When the wax is an ester wax obtained by reacting an acid component of stearic acid or behenic acid with any of alcohol components of stearyl alcohol, behenyl alcohol and 1,4-butanediol,
A wax having a difference between the extrapolation melting start temperature of DSC and the melting peak temperature measured at a heating rate of 5 ° C./min within 15 ° C. is preferable. If the temperature difference exceeds 15 ° C., the storage stability is lowered due to the low melting point component, which is not preferable. In order to narrow the difference between the extrapolative melting onset temperature and the melting peak temperature of the DSC, it is preferable to remove the low melting point component of the ester by solvent treatment or by a falling or centrifugal thin film distillation apparatus.

When the wax is an ester wax obtained by removing a low melting point component of rice bran wax or carnauba wax by a solvent treatment or a falling or centrifugal thin film distillation apparatus, DSC measured at a heating rate of 5 ° C./min. It is preferable that the difference between the extrapolation melting start temperature and the melting peak temperature of the above is within 15 ° C. If the temperature difference exceeds 15 ° C., the storage stability is lowered due to the low melting point component, which is not preferable.

In the case where the wax is a ketone wax obtained by decarboxylation of stearic acid at a high temperature in the presence of a metal oxide catalyst, the DSC extrapolation melting onset temperature and the melting peak temperature measured at a heating rate of 5 ° C./min. Preferably, the difference is within 10 ° C. If the temperature difference exceeds 10 ° C., the storage stability is lowered due to the low melting point component, which is not preferable. In order to narrow the difference between the extrapolation melting start temperature and the melting peak temperature of the DSC, it is preferable to remove the low melting point component of the ketone wax by a solvent treatment or a flow-down or centrifugal thin-film distillation apparatus.

In the case where the wax is 3-pentadecylphenoxyacetic acid obtained by reacting chloroacetic acid with 3-pentadecylphenol, which is a hydrogenated product of cashew nut oil, the complement of DSC measured at a heating rate of 5 ° C./min. It is preferable that the difference between the outer melting start temperature and the melting peak temperature is within 10 ° C. If the temperature difference exceeds 10 ° C., the storage stability is lowered due to the low melting point component, which is not preferable. In order to narrow the difference between the extrapolation melting onset temperature and the melting peak temperature of the DSC, it is preferable to remove the low melting point component of the reaction product by a solvent treatment or a flow-down or centrifugal thin-film distillation apparatus.

The fixing resin of the electrophotographic toner according to the present invention is a styrene / acrylic resin and / or a polyester resin, and those generally used as toner resins can be used. Specific examples of styrene / acrylic resin include styrene / acrylic acid copolymer, styrene / diethylamino / ethyl methacrylate copolymer,
Styrene-butadiene-acrylate copolymer,
Styrene / methyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / glycidyl methacrylate copolymer, styrene / butyl methacrylate / maleic anhydride copolymer, styrene / butyl methacrylate / acrylic acid copolymer Coalescence and the like.

As the polymerized monomer of the polyester resin,
The following can be mentioned. Specific examples of the acid component include malonic acid, succinic acid, glutaric acid, dimer acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydroterephthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, dimethyltetrahydrophthalic acid, and naphthalenetetra Examples thereof include carboxylic acid, trimellitic acid, and pyromellitic acid, and one or more of these are used.

Specific examples of the alcohol component include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, isopentyl glycol, hydrogenated bisphenol A, 1,3-butanediol,
Examples thereof include 1,4-butanediol, trimethylolpropane, and pentaerythritol, and one or more of these are used. The polyester resin obtained from these raw materials is manufactured by a usual method. The glass transition temperature is preferably 50 to 70 ° C.

The mixing ratio of the styrene / acrylic resin and / or the polyester resin to the polar wax of the present invention is preferably 1 to 10 parts by weight based on 100 parts by weight of the resin. When the amount of the polar wax is 1 part by weight or less, the toner easily adheres to the heating roller, and when the amount is 10 parts by weight or more, the transparency of the fixing resin is reduced, which is not preferable as a color toner.

As the colorant to be dispersed in the resin, known organic or inorganic pigments and dyes can be used. For example, carbon black, Hansa Yel
lowG, HansaYellow 5G, Disaz
o Yellow, Tartrazine Yellow
w Lake, Lake Red C, Carmine
6B, Phloxine Red, Quinacri
dones, Phthalocyanines, Ind
anthrene Blue, molybdo tungstophosphoric acid, disazo yellow, carmine 6B, copper phthalocyanine, nigrosine dye, aniline dye, chrome yellow,
Ultramarine blue and the like.

[0022]

EXAMPLES The effects of the present invention will be specifically described below with reference to examples. Example 1A 100 parts by weight of a styrene / butyl methacrylate copolymer (manufactured by Sanyo Chemical Industries, Hymer SBM-73F), an air oxide of Fischer Tropsch wax (manufactured by Nippon Seiro, melting point 105 ° C., acid value 11 mg KOH / g) 3 parts by weight were powder-mixed with a Henschel mixer at 3000 rpm for 15 minutes and then melt-kneaded at 150 ° C. for 10 minutes with a plast mill. Further, the sample was subjected to vacuum degassing for 30 minutes and cooled to obtain a sample for a transparency test. Further, 2 parts by weight of a copper phthalocyanine pigment and 2 parts by weight of a zinc salt of a salicylic acid derivative were added to the above mixture, and the mixture was kneaded at 150 ° C. for 10 minutes using a plastmill. After natural cooling and coarse pulverization with a Henschel mixer, the kneaded material was pulverized with a jet pulverizer, and a base toner having a particle diameter of 5 to 15 μ was obtained using an air classifier. Further, 1 part by weight of colloidal silica was added thereto and mixed with a mixer to obtain an electrostatic toner. Next, 6 parts by weight of an electrostatic toner is mixed with 100 parts by weight of iron powder having a particle size of 50 to 80 μm (made by Nippon Iron Powder) as a carrier, developed by a conventionally known electrophotographic method, and heated. The image was fixed by heating at a low temperature of 130 ° C. with a roller. The print after copying was evaluated for fixability, offset phenomenon, heating roller contamination, and the like.

Examples 2A to 7A and Comparative Examples 1A to 6A Toner preparation and copy tests were performed in the same manner as in Example 1A, except that the type of the polar wax was changed in place of the air oxide of the Fischer-Tropsch wax. Table 1 shows the physical properties of the polar wax, and Table 2 shows the evaluation results.

Example 1B Polyester resin (CG-20, manufactured by Dainippon Ink Industries, Ltd.)
3) 100 parts by weight of air oxide of Fischer-Tropsch wax (manufactured by Nippon Seiro, OX-0409, melting point 1)
3 parts by weight (01 ° C., acid value 19 mg KOH / g) were powder-mixed with a Henschel mixer at 3000 rpm for 15 minutes, and then melt-kneaded at 130 ° C. for 10 minutes in a plast mill. Further, the sample was subjected to vacuum degassing for 30 minutes and cooled to obtain a sample for a transparency test. Further, 2 parts by weight of a copper phthalocyanine pigment and 2 parts by weight of a zinc salt of a salicylic acid derivative were added to the above mixture, and the mixture was kneaded at 130 ° C. for 10 minutes using a plastmill. After natural cooling and coarse pulverization with a Henschel mixer, the kneaded material was pulverized with a jet pulverizer, and a parent toner having a particle diameter of 5 to 15 μ was obtained using an air classifier. Further, 1 part by weight of colloidal silica was added thereto and mixed with a mixer to obtain an electrostatic toner. Next, 6 parts by weight of an electrostatic toner is mixed with 100 parts by weight of iron powder having a particle size of 50 to 80 μm (made by Nippon Iron Powder) as a carrier, developed by a conventionally known electrophotographic method, and heated. The image was fixed by heating at a low temperature of 130 ° C. with a roller. The print after copying was evaluated for fixability, offset phenomenon, heating roller contamination, and the like.

Examples 2B to 7B and Comparative Examples 1B to 6B In the same manner as in Example 1B, the type of the polar wax was changed and a toner adjustment and copy test were performed. Table 1 shows the physical properties of the polar wax, and Table 3 shows the evaluation results.

<Transparency Test> The two-component melt-kneaded product of the fixing resin and the polar wax obtained in the example was poured into an aluminum cup, cooled and molded to a thickness of 10 mm, and then subjected to a spectrophotometer (Minolta spectrophotometer). The lightness L ^* (JIS Z 8722) was measured using a colorimeter CM-2022). Lightness L ^*
Is smaller, the transparency is better. If the lightness L ^* is larger, the transparency is worse and the color is whitened.

<Blocking test> 100 g of 30 g of the electrostatic toner pulverized and classified by a jet pulverizer was classified.
Was left at 45 ° C. for 3 days, and the aggregation state of the toner at that time was evaluated by a sieving measuring device.

<Extrapolation-melting start temperature of DSC> Using a differential scanning calorimeter (DSC-220 manufactured by Seiko Denshi Kogyo), -3.
The temperature was raised at a rate of 5 ° C./min from 0 ° C. to 160 ° C., and a melting curve at that time was obtained. The extrapolated melting onset temperature refers to the temperature at the intersection of the base line and the tangent from the maximum displacement point of the melting peak.

<Fixing property test> A roller copy temperature of a commercially available electrophotographic copying machine was set to 130 ° C., and an actual photographing test was performed.
The obtained fixed image was rubbed with a constant load, and the density reduction before and after rubbing was visually compared.

<Offset Test> An actual offset test was conducted by setting a roller temperature of a commercially available electrophotographic copying machine to 130 ° C. to carry out an actual photographing test. The offset was determined based on how the image was stained.

[0031]

Remarks) Content of polar wax Air oxide of Fischer-Tropsch wax having a melting point of 102 ° C. (acid value: 11 mg KOH / g, saponification value: 2)
7 mgKOH / g) Boric oxide (acid value: 3 mgKOH / g, hydroxyl value: 6) of paraffin wax (HNP-9) manufactured by Nippon Seiwa.
Urethane wax obtained by subjecting the wax to TDI modification. Ester wax of behenic acid and behenyl alcohol (acid value: 1 mgKOH / g, saponification value: 84 mgKOH)
/ G) Distilled rice bran wax to remove ester wax (acid value: 2 mg KOH / g, saponification value: 87 mg KOH / g) from which low boiling point component and gum component were removed Distilled diheptadecyl ketone (WAX T-1 manufactured by Kao) Ketone wax treated to remove low melting point components 3-pentadecylphenoxyacetic acid (acid value: 150 mg
KOH / g) Air oxide of Fischer-Tropsch wax having a melting point of 102 ° C. (acid value: 22 mg KOH / g, saponification value: 5)
0 mgKOH / g) Borate oxide of α-olefin (D-30) manufactured by Mitsubishi Chemical Corporation (acid value: 12 mgKOH / g, hydroxyl value: 80 m)
(gKOH / g) {circle around (10)} Urethane wax obtained by modifying the above wax with TDI. {11} ester wax of stearic acid and stearyl alcohol (acid value: 1 mgKOH / g, saponification value: 10)
(4 mg KOH / g) (12) FT100: Shell MDS, Fischer Tropush wax (13) Biscol 660: Sanyo Chemical Industries, polypropylene wax

[0033]

[0034]

[0035]

Normally, a non-polar wax having high crystallinity such as polyethylene wax or polypropylene wax is used for the toner in order to improve the high-temperature offset property at the time of fixing. However, such a non-polar wax has poor compatibility with the resin, and therefore, the transparency of the toner is hindered. This transparency is particularly important for color toners. As shown in Tables 2 and 3, it was confirmed that the toner containing the polar wax of the present invention had excellent transparency, no offset phenomenon to the heating roll, and excellent low-temperature fixability.

[0037]

By using the polar wax of the present invention, favorable thermal characteristics can be imparted to the toner. That is, the fixability at low temperature without impairing the transparency of the toner,
A toner having excellent offset resistance and excellent blocking resistance can be provided.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shin Taguchi 850 Oshima Oaza, Tokuyama City, Yamaguchi Prefecture Nippon Seiryu Co., Ltd. In the Research & Development Center, Inc. (72) Inventor Masashi Yamamoto 850, Oshima, Oaza, Tokuyama-shi, Yamaguchi Japan Nippon Seiro Co., Ltd. F-term in the Research & Development Center, Japan 2H005 AA01 AA06 AB02 CA04 CA08 CA14 DA06 EA03 EA07 EA10

Claims (8)

[Claims] 1. A styrene / acrylic resin and / or
In an electrophotographic toner using a polyester resin as a fixing resin, a carbonyl group, a carboxyl group, a hydroxyl group, an ester bond in a hydrocarbon as a release agent,
Among the urethane bonds, at least one or more polar groups are contained on an average of 0.07 or more per molecule, and the melting point is 65 or more.
A wax for electrophotographic toner, comprising using a polar wax having a temperature of from 110 to 110 ° C. 2. The wax is a wax oxide having an acid value of 1 to 20 mgKOH / g obtained by air oxidation of petroleum wax or Fischer-Tropsch wax, and is a complement of DSC measured at a heating rate of 5 ° C./min. 2. The wax for an electrophotographic toner according to claim 1, wherein the difference between the outer melting start temperature and the melting peak temperature is within 25 ° C. 3. A wax having a hydroxyl value of 50 to 90 mgKOH / g, obtained by subjecting any one of petroleum wax, α-olefin wax having a double bond at a terminal, and Fischer-Tropsch wax to air oxidation in the presence of boric acid. 2. The wax for an electrophotographic toner according to claim 1, wherein the wax is an alcohol type wax, and a difference between an extrapolation melting start temperature and a melting peak temperature of the DSC measured at a heating rate of 5 ° C./min is within 25 ° C. 4. A method according to claim 1, wherein said wax is urethane wax obtained by reacting said alcohol type wax with tolylene diisocyanate, and DSC measured at a temperature rising rate of 5 ° C./min.
2. The wax for an electrophotographic toner according to claim 1, wherein the difference between the extrapolation melting onset temperature and the melting peak temperature of the toner is within 25 ° C. 5. An ester wax obtained by reacting an acid component of stearic acid or behenic acid with any one of stearyl alcohol, behenyl alcohol and 1,4-butanediol.
2. The wax for an electrophotographic toner according to claim 1, wherein the difference between the extrapolative melting onset temperature and the melting peak temperature of the DSC measured at a heating rate of 5 ° C./min is within 15 ° C. 6. The wax is an ester wax obtained by removing a low-melting-point component of rice bran wax or carnauba wax by a solvent treatment or a falling or centrifugal thin-film distillation apparatus, and is measured at a heating rate of 5 ° C./min. 2. The wax for an electrophotographic toner according to claim 1, wherein the difference between the extrapolated melting start temperature and the melting peak temperature of the obtained DSC is within 15 ° C. 7. The wax is a ketone wax obtained by decarboxylation of stearic acid at a high temperature in the presence of a metal oxide catalyst, and has a DSC extrapolation melting onset temperature and a melting peak measured at a heating rate of 5 ° C./min. 2. The wax for an electrophotographic toner according to claim 1, wherein the temperature difference is within 10 [deg.] C. 8. The wax is 3-pentadecylphenoxyacetic acid obtained by reacting chloroacetic acid with 3-pentadecylphenol, which is a hydrogenated product of cashew nut oil, and is measured at a heating rate of 5 ° C./min. 2. The wax for an electrophotographic toner according to claim 1, wherein the difference between the extrapolated melting onset temperature and the melting peak temperature of the toner is 10 ° C. or less.