JPS5838781B2 - Manufacturing method of pressure fixable microcapsule toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an electrostatographic toner, and more particularly to a method for producing a novel microcapsule toner that can be fixed by pressure.

As conventional electrostatic photographic toners, heat-fixable toners are mainly used.

This type of toner is mainly made of thermoplastic resin, and is produced by softening the thermoplastic resin by heating, adding a coloring agent to the mixture, kneading it, and then pulverizing it.

However, the fixing method using heat-fixable toner has the following drawbacks.

(1) The temperature of the fixing device is heated for a long time to raise it above the softening point of the toner.

(2) A large amount of electric power is required to maintain the temperature of the fixing device above the softening point of the toner.

(3) If the temperature of the fixing device is set too high in order to increase the speed, the copy paper may burn, or in the worst case, there is a risk of fire.

On the other hand, there have also been proposals to increase the speed by lowering the temperature of the fixing device by using toner with a low softening point or toner that can be fixed only by pressure.

For example, Japanese Patent Publication No. 44-9880 discloses a pressure-fixable toner composition comprising a C6 to C25 aliphatic component;
No. 75033, JP-A-48-78931, JP-A-48-Sho.
No. 78936 and other documents describe electrostatic photographic developers made of soft polymers, but in order to produce these developers using conventional pulverization methods, (1) (2) Toners made by this method have a wide particle size distribution, and it is necessary to make the particle size uniform by classifying them, which increases manufacturing costs. (3) causes aggregation, bridging, and caking during toner production or storage; (4) adheres to carrier particles; and (5) causes a film-like stain on the surface holding the electrostatic latent image, resulting in repeated damage. If used, it will cause problems.

There are drawbacks such as.

Furthermore, Japanese Patent Publication No. 34-8561, U.S. Patent No. 308031
No. 8 describes recording by pressurization using encapsulated oil-based colorants, and US Pat. No. 3,080,250
specification, specification No. 3386822, and JP-A-1988
No. 71648 describes a method of imparting fixing properties to toner by crushing capsules containing a solvent, but in these toners, the core substance of the capsule is the liquid itself, and the formed image may not bleed. It has drawbacks such as "flow" and a solvent odor.

Further, JP-A No. 48-75032 discloses a pressure-fixing toner in which a soft polymer is encapsulated, but since the particles in this toner have poor fluidity, hydrophobic silica or other fluid is added. It is necessary to mix an agent, which impairs the pressure fixing properties and increases the pressure force required for fixing, which has disadvantages such as poor practicality.

The present invention eliminates the above-mentioned drawbacks and provides a method for producing a pressure-fixable microcapsule toner at low production cost.

Further, the present invention provides a method for producing a pressure-fixable microcapsule □ toner that does not cause problems such as aggregation and caking, and therefore does not cause any contamination on the surface of an electrostatic latent image.

Furthermore, the present invention provides a practical method for producing microcapsule toner that can be fixed with low pressure.

That is, the method of the present invention involves emulsifying and dispersing a non-aqueous solution or non-aqueous dispersion mainly composed of soft solids into an aqueous solution of a hydrophilic film-forming polymeric substance, and cuffing the emulsifying tube in water using the emulsifying tube as a core material. This capsule liquid is then mixed with an aqueous suspension of hard resin to form a turnip slurry, which is then spray-dried to form double-walled capsules.

In this case, in a non-aqueous solution or non-aqueous dispersion of a soft solid forming the core material and/or in an aqueous solution of a polymeric material and/or an aqueous suspension of a hard resin forming the outer walls (first wall and second wall). Mix in colorant.

Encapsulation methods for the core material include phase separation methods from aqueous solutions such as complex coacervation method, simple coacervation method, salt coacervation method, polymer insolubilization method by pH change, temperature change, and solvent removal, and interface method. Any known method capable of encapsulating a hydrophobic substance in an aqueous medium, such as a polymerization method or an in situ polymerization method, can be employed.

The soft solid used for the core material can be any material that has adhesive properties under pressure at room temperature, such as higher fatty acids such as stearic acid, palmitic acid, myristic acid, lauric acid, and capric acid, and metal salts thereof. , hydrogenated castor oil, cocoa butter, higher fatty acid derivatives such as methyl hydroxystearate, glycerol monohydroxystearate, higher aliphatic amides such as octadecaneamide, hexadecaneamide, tetradecaneamide, dodecanamide, decanamide, octaneamide, hexaneamide, etc. Waxes such as beeswax, wood wax, carnauba wax, white wax, microcrystalline wax, rosin, hydrogenated rosin,
Rosin derivatives such as rosin esters, drying oil-type or semi-drying oil-type alkyds, alkyd resins such as rosin-modified alkyds, phenol-modified alkyds, and styrenated alkyds, phenolic resins such as epoxy-modified phenolic resins, natural resin-modified phenolic resins, amino resin, silicone resin,
Condensation resins such as polyurethane, urea resin, and polyester, copolymerized oligomers of acrylic acid and long-chain alkyl acrylates, copolymerized oligomers of acrylic acid and long-chain alkyl methacrylates, and copolymerizations of methacrylic acid and long-chain alkyl acrylates. Oligomer, copolymerized oligomer of methacrylic acid and long-chain alkyl methacrylate, copolymerized oligomer of styrene and long-chain acrylic acrylate, copolymerized oligomer of styrene and long-chain alkyl methacrylate, ethylene-vinyl acetate copolymer, ethylene rubinyl To alkyl ether copolymers, ethylene-maleic anhydride copolymers, vinyl resins such as polystyrene, polyvinyl acetate, and polyvinyl chloride, polymers such as polyacrylic acid, polymethacrylic acid, and their esters, isobutylene rubber, and styrene. Examples include rubbers such as butadiene rubber, nitrile rubber, and chlorinated rubber, polyolefins such as polyethylene, petroleum residues such as asphalt, and giltnide.

Among these soft solids, when resins are used, those with low molecular weight are suitable.

The above soft solids are aliphatic hydrocarbons, aromatic hydrocarbons,
- Used in a state dissolved, swollen or dispersed in a non-aqueous solvent such as a logenated hydrocarbon or a mixture thereof.

The hydrophilic film-forming polymeric substances forming the first wall include gum arabic, gelatin, albumin, sodium alginate, carboxymethyl cellulose, hydroxyethyl cellulose, ethylene-sodium maleic anhydride copolymer, and vinylmethylniteryl maleic anhydride. (or ester thereof) copolymer, styrene acrylic acid-butyl methacrylate copolymer, and the like.

The hard resin forming the second wall is polycarbonate,
Polyester, polyamide, polyether, polyolefin, polystyrene, styrene acrylate copolymer, styrene-methacrylate copolymer, styrene-ethylenically unsporated monoolefin copolymer, styrene rubinyl ester copolymer, styrene rubinyl ether copolymer Polymer, styrene-acrylonitrile copolymer, styrene ~
Methacrylonitrile copolymer, styrene-acrylamide copolymer, styrene-α-methylene fatty acid monocarboxylic acid ester copolymer, styrene-vinylidene rogenide copolymer, polyvinyl acetate, or two or three of these
Copolymers or blends of more than the original are used.

Pigments and dyes such as carbon black are used as the coloring agent.

Examples are shown below.

Example 1 40wt% aliphatic hydrocarbon dispersion of vinyl acetate-lauryl methacrylate graft copolymer (solvent: Isovar H manufactured by Esso Standard) 62, and carbon black (Mitsubishi Carbon #44 manufactured by Mitsubishi Kasei ■) 3S' were added to Fl. Disperse and further add 5f of 10wt% toluene solution of terephthaloyl chloride? Dissolve it to make a core material solution.

Next, this solution was dispersed and emulsified in 500 ml of an aqueous solution in which 2.5 parts each of sodium bicarbonate and polyvinyl alcohol were dissolved, and then 10% hexamethylene diamine aqueous solution 501 was added with stirring to transform the core material solution into a polyamide film. A capsule solution coated with was prepared.

On the other hand, an aqueous suspension of polyvinyl acetate (A-522 manufactured by Daicel ■, solid content 50%) 65? carbon black (Co11oi manufactured by Columbia Carbon Company, USA)
Prepare a liquid in which dexA 5 ) 2 S' is dispersed,
A capsule slurry was obtained by uniformly mixing with the capsule liquid.

Finally, this capsule slurry was double encapsulated by spray drying using a Niro atomizer at an inlet temperature of 135°C, an outlet temperature of 85°C, and an injection pressure (compressor pressure) of 60 kg/cd, thereby producing a pressure fixable toner. Obtained.

Example 2 Carbon black (Mitsubishi Carbon #44
) 3fI is dispersed and further terephthaloyl chloride 0
．． 5P was dissolved to prepare a core material solution.

Next, this core material solution was emulsified and dispersed in 500 ml of an aqueous solution in which 2.59% of sodium bicarbonate and polyvinyl alcohol were dissolved, and 50 tons of a 10% aqueous hexamethylene diamine solution was added with stirring. was added to obtain a capsule liquid in which the core material solution was coated with a polyamide film.

On the other hand, the aqueous suspension 651 of polyvinyl acetate used in Example 1 was uniformly mixed with the encapsulation liquid to obtain a capsule slurry.

Finally, this capsule slurry was double encapsulated by spray drying using a Niro atomizer at an inlet temperature of 135°C, an outlet temperature of 85°C, and a compressor pressure of 5.6 kg/crl to obtain the desired pressure-fixable toner. Obtained.

Example 3 5wt% gum arabic aqueous solution 100S' IN NaO
Adjust the pH to 10 with H, add 50P of a pH 10 NaOR aqueous solution, disperse 2f of carbon black (Mitsubishi Carbon #44) in this solution, and add 100r of a 20wt% toluene solution of lauryl methacrylate copolymer. Uniformly emulsify and disperse with a mixer.

This was mixed with 100 S' of a 5 wt% aqueous gelatin solution with a pH of 10 prepared in advance, and the temperature was kept at 50 ± 1°C, and acetic acid was added dropwise over about 2 hours with slow stirring to lower the pH to 4.8. The gelatin-gum arabic mixture was phase separated around the toluene solution dispersion of lauryl methacrylate.

Next, add 5℃ water to this system at 130? was added and stirred for 30 minutes while maintaining the liquid temperature at 5°C.
After adding 30 g of a 10 wt % aqueous solution of NTREZ AN-119) and adding 31 g of a 37% formaldehyde aqueous solution while preventing agglomeration of capsule particles, the pH of the solution was raised to 10.

While stirring, the temperature was raised to 50° C. over about 1 hour to harden the capsule walls.

On the other hand, the aqueous suspension 100 of polyvinyl acetate of Example 1? Carbon black (Co11oide)
x A5) 3? A dispersed liquid was prepared, mixed with the above capsule liquid, and uniformly stirred with a stirrer to obtain a capsule slurry.

Finally, this capsule slurry was spray-dried using a Niro atomizer under conditions of an inlet temperature of 135° C., an outlet temperature of 85° C., and a compressor pressure of 5.6 kg/crtt to obtain a pressure fixable toner.

Example 4 Urea 100f in 37% formaldehyde aqueous solution 2751
? Mix and add 10% ethanolamine aqueous solution to p
The temperature was adjusted to 7.5, and stirring was continued for about 2 hours at a temperature of 70°C to form a urea-formaldehyde initial condensate.

This initial condensate 10I? was dissolved in water 1901, and this aqueous solution was mixed with 100 g of a 10 wt % toluene solution of styrene-butadiene rubber (A, Turprene 303 manufactured by A Chemical Co.), and emulsified and dispersed for about 30 minutes using a homomixer.

While stirring the resulting dispersion, citric acid was added to lower the pH to 3.5, and the temperature was kept at 48 ± 2°C while stirring for about 5 hours. Subsequently, urea-formaldehyde resin was precipitated around the emulsified droplets and hardened. and encapsulation was performed.

On the other hand, carbon black (Co11o) was added to the aqueous suspension 101' of polyvinyl acetate used in Example 1.
idex A, 5) 5 F was dispersed, and this dispersion liquid was mixed with the above capsule liquid and uniformly stirred with a stirrer for about 10 minutes to form a capsule slurry.

Finally, this capsule slurry was spray-dried using a Niro atomizer under conditions of an inlet temperature of 135° C., an outlet temperature of 85° C., and a compressor pressure of 6.0 kg/crrt to obtain a pressure fixable toner.

Example row 5 Add 10 (l) of urea to 2751 37% formaldehyde aqueous solution.
and then add 10% ethanolamine solution to adjust the pH.
After adjusting the temperature to 7.5, the mixture was stirred at a temperature of 70° C. for about 2 hours to form a urea-formaldehyde initial condensate.

This initial condensate ICI was dissolved in 190P of water, and carbon black (Mitsubishi Carbon #44) El' and 10 wt % toluene sol 1501 of aluminum stearate were mixed with this aqueous solution and emulsified and dispersed for about 30 minutes using a homomixer.

Next, citric acid was added to this dispersion while stirring to adjust the pH.
to 3.5, and while keeping the temperature at 48±2℃,
The mixture was stirred for a period of time to harden and precipitate the urea-formaldehyde resin around the emulsified droplets of the aluminum stearate sol, thereby performing encapsulation.

On the other hand, a polystyrene aqueous suspension (manufactured by Dow Chemical Company, USA, Dow 201, solid content 50 wt%) 100
f was mixed with the above capsule liquid and stirred uniformly for about 10 minutes using a stirrer to obtain a capsule slurry.

Finally, this capsule slurry was spray-dried using a Niro atomizer under conditions of an inlet temperature of 135° C., an outlet temperature of 85° C., and a compressor pressure of 5.6 kg/crrr to obtain a pressure fixable toner.

Example row 6 After adjusting 10 CI of 5 wt% gum arabic aqueous solution to pH 10 with 1N NaOH,
Add OH aqueous solution 5C1.

In this liquid, styrene-butadiene rubber (
50 P of a 10% toluene solution (same as in Example 4) was added and uniformly emulsified and dispersed using a homomixer.

To this was added 1 ooy of the prepared 5 wt % gelatin aqueous solution with pH 10, and while keeping the temperature at 50 ± 1°C, acetic acid was added dropwise over about 2 hours with slow stirring until the pH reached 4.8. Gelatin-gum arabic particles were phase separated around toluene emulsified droplets of rubber.

Next, 15['] of water at 5°C was added to this system, and the mixture was stirred for 30 minutes while maintaining the liquid temperature at 5°C.
After adding t% aqueous solution 31' and adding 37% formaldehyde aqueous solution 3i while preventing agglomeration of the produced capsule particles, the pH of the solution was raised to 10.

While stirring, the temperature was gradually raised to 50° C. over about 1 hour to harden the capsule walls.

On the other hand, an aqueous suspension of polystyrene (Dow 201 manufactured by Dow Chemical Company, USA, solid content 50 wt%) 5M'
carbon black (Co11oidexA5) 3fI
This dispersion was mixed with the above capsule liquid and uniformly stirred for about 10 minutes using a stirrer to obtain a capsule slurry.

Finally, this capsule slurry was spray-dried using a Niro atomizer under the conditions of an inlet temperature of 130° C., an outlet temperature of 80° C., and a compressor pressure of 5.6 kg/crtl to obtain a pressure fixable toner.

Example 7 10wt of styrene-butadiene rubber used in Example 4
% toluene solution 62. Dissolve 0.51 terephthaloyl chloride in El to prepare a core material solution.

Next, this solution was emulsified and dispersed in 500rrll of an aqueous solution containing 2.5% of each of sodium bicarbonate and polyvinyl alcohol, and 10% ethylene glycol aqueous solution 51' was added with stirring to coat the core material solution with a polyester film. A capsule solution was prepared.

On the other hand, 65 g of the same polystyrene aqueous suspension as in Example 6 was mixed with carbon black (Co11oidex A,5) 5? was dispersed, and this dispersion was uniformly mixed with the capsule liquid to obtain a capsule slurry.

Finally, this capsule slurry was spray-dried using a Niro atomizer at an inlet temperature of 135°C, an outlet temperature of 85°C, and a compressor pressure of 6kg/cd.
A double encapsulated pressure fixing toner was obtained.

Example 8 A core material solution was prepared by dissolving 0.51 g of terephthaloyl chloride in 62.59 g of a 50 wt % toluene solution of inbutyl methacrylate polymer.

Next, this solution was emulsified and dispersed in 500 ml of an aqueous solution containing 2.5 ml of each of sodium bicarbonate and polyvinyl alcohol, and 2.5 ml of a 10% ethylenediamine aqueous solution was added with stirring. was added to prepare a capsule solution in which the core material solution was coated with a polyamide film.

On the other hand, carbon black (Co11ojdex A 5 ) 5 ? A dispersion liquid was prepared, and this was uniformly mixed with the capsule liquid to form a capsule slurry.

Finally, this capsule slurry was spray-dried using a Niro atomizer under the conditions of an inlet temperature of 135° C., an outlet temperature of 85° C., and a compressor pressure of 6 kglcr to obtain a double encapsulated pressure fixable toner.

Comparative Example For comparison, a toner was prepared according to the method described in the Examples of Japanese Patent Application Laid-open No. 75032/1983.

That is, a mixed solvent of chloroform and cyclohexane with a volume ratio of 4:3 is 450? Polystyrene (PS-2 manufactured by Dow Chemical Company, USA) 24f and phenol-formaldehyde resin (ERLB-0449 manufactured by Union Carbide Company, USA)
) was dissolved to create a mixed resin solution.

To this solution, 25 g of carbon black (Peerless 155, manufactured by Columbia Carbon Co., USA) was added and uniformly dispersed using a homomixer.

Next, this dispersion was heated using a Niro atomizer at an inlet temperature of 68°C, an outlet temperature of 53°C, and a compressor pressure of 61y/y.
The mixture was spray-dried and granulated under crl conditions.

The obtained particles tend to aggregate, so after drying under reduced pressure in a vacuum dryer overnight to remove residual solvent, 0.5% of hydrophobic silica powder (Erosil) was added to further improve fluidity.
The final toner particles were prepared by adding and mixing wt%.

Using the toners of the practical and comparative rows obtained as above, an electrostatic latent image formed on a commercially available electrophotographic photosensitive material was developed and transferred, and then fixed using a variable pressure steel fixing roller. However, the results shown in the table below were obtained.

Claims (1)

[Claims] 1 A non-aqueous solution or non-aqueous dispersion mainly consisting of a soft solid is emulsified and dispersed in an aqueous solution of a hydrophilic film-forming polymeric substance, encapsulated in water using this emulsified part as a core material, and then this capsule liquid is 1. A method for producing a pressure-fixable microcapsule toner, which comprises mixing the toner with an aqueous suspension of hard resin to form a capsule slurry, and spray-drying the slurry to form double-walled capsules.