JPS6389868A - New crosslinked system for making useful toner in electrophotography - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to toners useful in electrophotographic equipment.

Toners useful in dry electrophotographic development can be made by melt dispersing the colorant in a resin and milling the cooled product to the desired particle size. Crosslinked resins are used to alleviate offset problems that can occur in equipment with hot roll fusing equipment. However, while colorants disperse well in uncrosslinked resins, they do not disperse well in such resins after crosslinking, and insufficient colorant dispersion results in incomplete photographic multilayering.

U.S. Patent Nos. 4,217,406 and 4,565,763
No. 2, No. 1, No. 1, No. 1, No. 1, No. 1, No. 1, 2003, 2005, discloses a method in which an uncrosslinked or slightly crosslinked resin is simultaneously crosslinked and melt blended with a colorant and then ground into a dry toner.

However, these methods are limited to certain functional group-containing resins. Therefore, known toner resins that do not contain such functional groups cannot be used in the disclosed system.

It would be advantageous to devise a system that can utilize a wide variety of toner resins and that can simultaneously melt blend and crosslink the toner resins. However, such systems must be designed so that colorants and other additives that are melt blended with the resin do not adversely affect the crosslinking reaction.

According to the present invention, a method of making a toner comprising the steps of melt blending a resin with a colorant and then grinding the mixture comprises:
The following formula: (wherein R is an organic radical, y and Z are 0 to 10
and y+z is an integer from 2 to 10.

) is characterized in that the resin is crosslinked during the melt blending process by melt blending the resin and colorant in the presence of a polyfunctional azide at a temperature sufficient to crosslink the resin. Surprisingly, it has been found that the required colorants and other useful toner additives do not significantly interfere with the ability of the polyfunctional azide to crosslink the resin.

Resins useful in this invention are any organic resins with carbon-hydrogen bonds. Although it may already be a slightly crosslinked resin, because of monodispersity issues it is preferred that the resin be a linear or branched non-crosslinked resin.

Resins found to be particularly useful in the present invention include about 40-90% by weight styrenic material (preferably styrene) and about 10-60% by weight other vinyl monomers other than styrene (e.g. 20% by weight in the alkyl group). Copolymers of alkyl acrylates or alkyl methacrylates having up to or more carbon atoms, including branched alkyl esters and cycloalkyl esters of acrylic and methacrylic acids, such as cyclohexyl methacrylate. Other useful resins are 40-90% by weight
of styrene, about 5 to 50% by weight of alkyl groups containing 1 to 4
lower alkyl acrylates or lower alkyl methacrylates (e.g., methyl, ethyl, impropyl or butyl esters) having about 6 to 20 or more carbon atoms in the alkyl group in about 5 to 50 weight percent is a terpolymer of higher alkyl acrylate or higher alkyl methacrylate (for example, ethylhexyl ester of acrylic acid or methacrylic acid) having carbon atoms of . ″
Styrenic materials include monomers or monomer mixtures of the formula: where R is hydrogen, halogen, lower alkyl (ie, C-C4 alkyl), or halogenated lower alkyl.

Other resins particularly useful in the present invention include one or more dicarboxylic acids and one or more dihydric alcohols that can react with each other to form a polymer of individual units linked by ester groups. It is a polyester manufactured from

Examples of dicarboxylic acids that can be used to make polyester resins are terephthalic acid and isophthalic acid (including substituted terephthalic acids and isophthalic acids).

and cyclohexanedicarboxylic acid. Examples of dihydric alcohols that can be used in the preparation of polyesters include bis(hydroxyalkoxy-phenyl) alkanes having from 1 to about 4 carbon atoms in the alkoxy group and from 1 to about 10 carbon atoms in the alkane group. cyclohexane dialkanol having from 2 to about 10 carbon atoms in the alkanol group, and alkylene glycols such as tetramethylene glycol having from 2 to about 10 carbon atoms in the alkylene group.

Examples of resins useful in the present invention include U.S. Pat.
No. 92, No. 4217406 and No. 456576
No. 3, the contents of which are hereby incorporated by reference.

Polyfunctional azides that can be used according to the invention are known crosslinking agents. Suitable azides are disulfone azides in which R is an aliphatic, aromatic, or alicyclic group (i.e., y=○, z=2 in the above formula), and R is an aliphatic, aromatic, or alicyclic group. Examples of useful polyfunctional azides are diazidoformate, which is an aromatic group when separated from the azidoformate group by a group group (i.e., y = z + Z = O), as described in U.S. Pat. No. 3,261,785; No. 3058944, No. 3284421 and No. 3
No. 585,103, the contents of which are incorporated herein by reference. The amount of polyfunctional azide crosslinker used is from about 0.1 to about 10%, preferably from about 0.5 to about 2%, based on the weight of the resin. The specific amount required will depend on the molecular weight of the resin and will be determined by one skilled in the art.

The coloring agent used in the present invention is -1 index (Col
Our Index) 2nd Edition, Volumes 1 and 2 (Bradford and Yorkshire: Dyers and Colorists Association, 1956). Examples of such colorants are disclosed in the above-mentioned US Pat. Nos. 3,938,992 and 3,565,763. Preferably, the amount of colorant used is from about 2 to about 20%, preferably from about 8 to about 10%, based on the weight of the toner (i.e., crosslinked resin, colorant, and optional ingredients).

Optional ingredients useful in making toners according to the present invention are known in the art, such as surfactants.

Conductive and magnetic materials. Examples of this type are U.S. Pat. No. 3,577,345 (herein incorporated by reference);
and US Pat. No. 3,938,992 and US Pat. No. 4,565,763, cited above.

Melt blending is carried out in accordance with the open invention at a temperature and for a period of time sufficient to react substantially all of the polyfunctional azide crosslinker and resin. The temperature and time will depend on the azide crosslinker used and will be determined by one skilled in the art. Preferably, the temperature is about 40
℃ to about 220'C. For example, when using a suitable disulfonazide, a suitable temperature is about 170°C.
to about 220°C, and when a suitable diazide formate is used, the preferred temperature is about 40°C to about 1
It is 70°C.

Preferably, the time period is from about 1 minute to about 1 minute, depending on the temperature of use.
It's time. Generally, at least about 5 times the half-life of the azide (ie, the time required to decompose 172 of the azide) at a given temperature is required.

The non-crosslinked resin preferably has an effective fusing range of at least about 10°C, most preferably at least about 2°C.
It is crosslinked according to the invention to an extent sufficient to spread by 0°C. “Useful fusing range
range) is known in the art as the temperature range at which the toner will hot roll fuse to the paper in an electrophotographic copier without fracturing or sticking to the roll. fusion latitude
”. Tests for determining the effective fusion range are well known, for example as described in the above-mentioned US Pat. No. 3,938,992.

The characteristic time (Tw) of a given resin is useful in estimating its effective fusion range. The Tw of the resin can be determined from measurements obtained using a mechanical spectrometer. In a spectrometer, the resin sample is placed on two parallel plates, one of which is made to vibrate at frequencies ranging from = 0.1 rad/sec to = 400 rad/sec.
placed between. Two types of tests are performed: frequency scans and temperature scans.

In the frequency scan, the sample was placed between two parallel plates (diameters 12, 5 m) with a gap of 2 m (during the test).
placed between. Keep the temperature constant and 0.1-4
Test the frequency of 00 radians for 7 seconds. Elastic modulus or storage modulus G' (dyne/an), loss modulus G'
(dyne/an) and complex viscosity n11 (boys)
Viscoelastic properties such as are obtained. The degree of crosslinking is G' and n11
This can be observed by comparing the values of This relational expression is as follows: [In the formula, Tw is the characteristic time at the vibration frequency, G' is the elastic modulus (dyne/aa), n material is the complex viscosity (voice), and V is the vibration characteristic time. It is a characteristic time expressed as a number (7 radians). The characteristic time is the time required for the deformed polymer to re-achieve its equilibrium shape within the polymer strip. It is clear that the characteristic time is the ratio of the elastic response of the polymer to the viscous response upon application of stress. The long characteristic time is suitable for use in heat-pressure fusing systems.

If the characteristic time is short compared to the time of application of the stress, the polymer will tend to crumble in the melt, resulting in offset; preferably, the toner of the present invention is 1 (140° C.) for a long time (more preferably longer than about 0.4 seconds).

Grinding according to the invention can be achieved, for example, in US Pat. No. 4,555,466.
No. 4,543,312, the contents of which are incorporated herein by reference, using methods known to those skilled in the art. Of course, it will be clear to those skilled in the art that the toner must be cooled after crosslinking to below the glass transition temperature (Tg) of the crosslinked resin before commencing grinding. The Tg of resins crosslinked according to the present invention will vary over a wide range and will generally be from about 0<0>C to about 90<0>C. Preferably, comminution is carried out using a fluid energy mill.

Toners made in accordance with the present invention can be mixed with carriers to form two-component developers.

Mixing is generally done by dry blending. The carrier can be non-magnetic or magnetic. Non-magnetic carriers include glass beads, inorganic crystals (eg, sodium chloride), hard resin particles, total refraction particles, etc. Ferromagnetic materials include iron, cobalt, nickel, and various alloys.

Magnetic carriers can be coated with film-forming polymers such as those described in the following patents: Mirror (M
U.S. Pat. No. 3,547,822 (1970
No. 3532512 (January 4, 1972); McCabe U.S. Patent Application No. 236765 (March 21, 1972); Kasper U.S. Patent Application No. 2365114 No. (March 21, 1972); U.S. Patent No. 23661
No. 4 (March 21, 1972), the contents of which are incorporated herein by reference, include fluoropolymers such as polytetrafluoroethylene, polyvinylidene fluoride, and their copolymers. is included.

Two-component developers made in accordance with the present invention consist of about 1-15% by weight toner and 85-99% carrier. The average particle size of the carrier is 30 to 1200 microns,
Preferably it is 60 to 200 microns. Examples of useful carriers are disclosed in the aforementioned US Pat. No. 3,938,992.

The toner made according to the present invention, as mentioned above,
It can include magnetic materials such as iron particles or iron oxide. This type of toner is called a single component developer and does not require a separate carrier as is required in two component developers. Single component developers made in accordance with the present invention contain about 30-70% by weight magnetic material.

In order to more precisely define the invention, the following examples are presented. However, the present invention is not limited thereto. All parts and percentages in the examples are by weight unless otherwise specified. All molecular weights in the examples are weight average molecular weights unless otherwise specified.

1. Heat a melt blender (Plasticorder, C, W, Brabender) with a five-segment sigma roller design to 175°C to obtain an Mw (weight average molecular weight measured by size exclusion chromatography) of approximately 80,000. Yes.

And melt index (150℃, 2.16kg)
8.8 kg/10 min of 53 parts of 80% styrene-20% n-butyl acrylate copolymer and 0.9275 parts of disulfonazidotridecane (80% di-substituted isomers and 20% mono- and tri-substituted ones). Loaded.

This mixture was kneaded at 175° C. and 70 rpm for 30 minutes.

The product was partially gelled, so no molecular weight data were obtained.

The TvJ (140°C) of this product is 0.76 seconds and the melt index (150°C) is 0.25 g/10 min.
, 2.16 kg).

Controls were cross-crossed without the use of diazide crosslinker.

The product had a My of 77,000 and a MN (number average molecular weight determined by size exclusion chromatography) of 40,600 and was soluble in organic solvents. The characteristic time calculated from rheological data is Tw = L (140°C) = 0
．． It was 152 seconds.

Crosslinking was carried out in the presence and absence of a colorant (i.e., carbon black) to demonstrate that the crosslinking ability of the five-pronged polyfunctional azide does not have a significant negative effect on the present invention.

In the case of a control (colorant failure), the styrene-acrylic acid n-
100 parts of butyl copolymer and 1.5 parts of 1,10-disulfoneazidodecane were charged. This mixture is 175
The resin was crosslinked by kneading at 70 rpm for 45 minutes. Then add 11 parts of carbon black and heat to 175℃.
Mixed for an additional 15 minutes at 70 rpm. The characteristic time of the control was Tυ=1(140°C)=0.91114 seconds.

In this example, a preheated plasticorder was loaded in the same way as the control, but before crosslinking, carbon black 11
70% at 175°C.
Kneaded for 60 minutes at rpm. Tw=1 (140°C) was 0.888 seconds. Comparison of characteristic times shows that crosslinking was not significantly affected by the presence of colorant.

Example 3 A mixture of 100 parts of the styrene-n-butyl acrylate copolymer used in Example 1 and 1.5 parts of p,ρ'-oxybis(benzenesulfonazide) is placed in a plasticorder along with colorants and other toner additives. Load, 17
The mixture was kneaded at 5°C for 30 minutes. The product contained 17% gel and had a characteristic time Tw = 1 (140°C) = 0.93 seconds.

This example was similar to Example 3, except that the resin used was 57% styrene-43% n-butyl methacrylate resin (
It was about 70,000 yen). This product is 40.8
% gel, characteristic time T = 1 (140°C) = 0.
It showed 86 seconds.

This example was similar to Example 3, except that 90% styrene-10% acrylic material with a weight average molecular weight of 45,000 was used.
-Butyl copolymer and 2.0 parts of diazide were used. This product has a gel content of 27% and a characteristic time TV=
1 (140°C) = 0.87 seconds.

The following experiments were conducted to demonstrate that the use of polyfunctional azides according to the present invention increases the fusing latitude of toners.

As a control, 540 parts of 50% styrene-30% methyl methacrylate-20% 2-ethylhexyl acrylate terpolymer (Mdo approx. 60,000) and 60 parts of carbon black (Black Pearls 1000, Cabot) were milled on a two-roll mill. Melt blending was performed at 175°C using

The mixture was cooled to room temperature and the product was milled in an impact mill (Willey mill) and a fluid energy mill followed by particle classification to obtain a toner with an average particle size of about 10 microns. This toner (4% by weight) was mixed with metal carrier beads (NV-30, International Communication Materials Industries, Inc.) to prepare a developer. Fusing latitude (ie, offset temperature minus minimum fusing temperature) was measured using a commercially available electrophotographic copier loaded with developer. The copying machine was improved so that the surface temperature of the melting roll could be changed and measured.

The speed of the fuser roll was 2.125 inches/second, and the pressure in the nip between the fuser roll and the pressure roll was 19 pounds per lineal inch. The paper with the unfused toner image was passed through the nip of the roll.

The lowest temperature at which the toner fuses to the paper without offset (minimum fusing temperature) is determined using an adhesive tape test with a zero width of 1.
A 9 nn adhesive tape (Scotch 810 Magic Transparent Tape, 3M Corporation) was applied to the roll fused image and immediately peeled off at a 180° angle. The minimum fusing temperature is the lowest temperature at which the toner is not pulled off with the tape. The offset temperature (minimum temperature at which toner adheres to the fuser roll) was measured by increasing the fusing temperature in 10°C steps above the minimum fusing temperature.

As an example of the invention, the control terpolymer 534.6
Part, PyP'-oxybis(benzenesulfone azide)
5.4 parts and carbon black (Black Pearls 1
000) were loaded into a two roll mill.

This mixture was maintained at 175°C. The 15 minute size compound showed a significant increase in viscosity and mixing continued for a total of 60 minutes. Toner and developer were made in the same manner as the control. The fusing latitude of the crosslinked product (measured in the same way as the control) was 65°C.
It was bigger. The minimum fixation temperature is 145°C and the offset is wt at any temperature tested up to 210°C.
It wasn't noticed.

Claims (1)

[Claims] 1. A toner manufacturing method comprising a step of melt-blending a resin and a colorant, then cooling and pulverizing the mixture, the improvement of which is as follows: ▲The mathematical formula, chemical formula, table, etc. ▼ (In the formula, R is an organic radical, y and z are 0 to 10
and the sum of y and z is an integer from 2 to 10) at a temperature sufficient to crosslink the resin. The method above comprises simultaneously crosslinking the resin during the melt blending step by melt blending. 2. The method of claim 1, wherein the resin is crosslinked until Tw=1 at 140°C is greater than about 0.4 seconds. 3. A product made by the method described in claim 2. 4. A two-component developer comprising the product according to claim 3 and a carrier. 5. The method of claim 1, wherein the resin is (a) a copolymer of a styrenic material and an acrylate or methacrylate, or (b) a polyester resin which is the reaction product of a dicarboxylic acid and a dihydric alcohol. 6. The method according to claim 1, wherein the polyfunctional azide is diazide formate or disulfone azide. 7. The method of claim 1, wherein the crosslinking is carried out at a temperature of about 140<0>C to 220<0>C. 8. The method of claim 1, wherein the resin is crosslinked to extend its effective fusion range by at least 10°C. 9. Organic resin with carbon-hydrogen bonds, colorant, and the following formula: ▲Mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R is an organic radical, and y and z are 0 to 10
and the sum of y and z is an integer from 2 to 10. 10. The composition of claim 9, wherein the organic resin is (a) a copolymer of a styrene material and an acrylate or methacrylate, or (b) a polyester which is the reaction product of a dicarboxylic acid and a dihydric alcohol. 11. The composition according to claim 9, wherein the polyfunctional azide is diazide formate or disulfone azide.