KR101202804B1 - Method for manufacturing of particle external additive for e-paper using carbon black and particle external additive for e-paper using carbon black prepared by using the method - Google Patents

Abstract

The present invention relates to a method for producing an electronic paper particle additive using carbon black, and to an electronic paper particle additive using carbon black prepared using the same, wherein nitric acid is added to the first solvent containing carbon black to react the reaction. An amino acid donating step of preparing carbon black having amino groups; And a charge imparting step of adding and reacting ammonia water to the second solvent to which the carbon black having the amino group is added.
According to the present invention, by using the solution adsorption method, not only can the external additive be adsorbed to the particles more quantitatively and uniformly, but also due to the chemical bonding, the durability can be remarkably improved. In addition, there is an advantage that can suppress the aggregation between particles and significantly improve the fluidity.

Description

Manufacturing Method of Particle Additives for Electronic Paper Using Carbon Black and Particle Additives for Electronic Paper Using Carbon Black Manufactured Using Carbon Black -PAPER USING CARBON BLACK PREPARED BY USING THE METHOD}

The present invention relates to a method for producing an electronic paper particle additive using carbon black and to an particle additive for electronic paper using carbon black prepared using the same. More specifically, unlike the conventional method, a solution adsorption method is used. By chemically adsorbing functional groups on the external additives, a method of producing an electronic paper particle additive using carbon black that imparts a strong charge to particles and prevents agglomeration between particles and significantly improves durability and fluidity. It relates to a particle external additive for electronic paper using the carbon black produced using the same.

BACKGROUND ART Conventionally, as an image display device replacing a liquid crystal display device (LCD), electronic paper using techniques such as an electrophoretic method, an electrochromic method, a thermal method, and a two-color particle rotation method has been proposed. These prior arts are considered to be a technology that can be used in an inexpensive image display device because of the advantages of having a wider viewing angle closer to a normal printed matter, a smaller power consumption, and a memory function than LCDs. , Electronic paper and the like are expected.

The dual electronic paper technology uses the rapid movement of microparticles by an electric field to electrostatically move charged particles floating in a certain space to display colors. Therefore, even if the voltage is removed, the image does not disappear because there is no change in the position of the particles, so that the effect as if printed on paper is printed. In other words, it does not emit light by itself, but the visual fatigue is very low, so it is possible to enjoy a comfortable viewing like a real book, and the panel's flexibility is high enough to bend and the thickness can be formed very thin. There is great expectation as a display device technology. In addition, as mentioned, power consumption is extremely low since the displayed image is maintained for a long time unless the panel is reset, thereby making it excellent as a portable display device. In particular, low prices due to simple processes and low cost materials are expected to contribute to the popularization of electronic paper.

Electronic paper techniques generally used include electrophoretic methods for microencapsulating a dispersion consisting of dispersed particles and a colored solution, and disposing the dispersion liquid between opposing substrates to cause particles to move in the liquid; Without using a solution, two or more kinds of particles having different colors and charging characteristics are enclosed between at least one transparent substrate, and an electric field is applied to the particles from an electrode pair consisting of electrodes formed on one or both of the substrates. A collision charging method has been proposed in which an charged particle having a different polarity is moved in a different direction by a Coulomb force to display an image.

Regardless of which type of electrophoresis method or collision charging method is used, a technique for forming a charged particle having a fluidity (hereinafter referred to as a 'fluid particle') should be accompanied. The structure which gives fluidity | liquidity is shown by coating the same external additive.

The flowable particles include an external blending method using a mixer by adding an external additive to a dispersion solvent containing the particles. The flowable particles in this manner, the particles and the external additives are physically bonded, due to the limitation of the durability of the physical bonds, there is a problem that the external components easily fall off.

When the external additives fall easily in this way, the charged particles cannot sufficiently respond to the same applied voltage, and the charge characteristics also change easily, resulting in a problem of deterioration in image quality. In addition, the longer the use time due to the departure of the external additive, there is a problem that the probability of occurrence of aggregation between the particles increases.

In addition, since the physical bonding, due to the electrostatic attraction between the particles and the external additive, there is a problem that the binding between the particles and the external additive is not quantitatively and uniformly.

In addition, in the case of the polymer particles used in the flowable particles, a polymerization method according to emulsion polymerization, dispersion polymerization or suspension polymerization is used. Since the polymer particles thus prepared mostly exhibit lipophilic surface properties, hydrophilic functional groups are formed on the surface. It is difficult to apply a new polymerization method for the introduction of the hydrophilic functional group in order to obtain the polymer particles bound, and unlike most commercial lipophilic polymer particles, very high in order to obtain the polymer particles into which the hydrophilic functional groups are introduced. In addition to the cost, there is a problem in that a cumbersome and inexpensive manufacturing method such as using a surfactant is used.

In addition, the binding problem between the particles and the external additives causes the same problems as described above in the binding of the external additives and the substances added to the external additives.

Therefore, in order to solve various problems such as fluidity, durability, and prevention of particle aggregation of the fluid particles, the development of a method for solving such problems by modifying the external additive itself is required, and effectively There is a need for development of a process for bonding, and a process for chemically and uniformly bonding external additives to flowable particles, rather than physically, and simply implementing such bonding.

The present invention is to solve the above problems, unlike the prior art, by using a solution adsorption method, not only can adsorb functional groups to the external additive more quantitatively and uniformly, but also due to chemical bonding, significantly improve the durability An object of the present invention is to provide a method for producing an electronic paper particle additive using carbon black and an electronic paper particle additive using carbon black prepared using the same.

In addition, by synthesizing an amino group to the carbon black, the production method of the particle external additive for the electronic paper using the carbon black that can suppress the aggregation between particles and significantly improve the fluidity and the electronic paper using the carbon black prepared using the same It is an object to provide a particle external additive.

In addition, by reacting carbon black with an amino group with ammonia water and giving sufficient charge to the external additive, a strong charge is formed throughout the particles, thereby increasing the fluidity of the particles and significantly reducing inter-particle interference. An object of the present invention is to provide an electronic paper particle additive for electronic paper using the carbon black, and an electronic paper particle additive for carbon paper prepared using the same.

In addition, by effectively preparing the external additive through the optimal material and its content, it is possible to form chemical bonds simply and economically, and in particular, by increasing the color of the white particles, the external additive improves the contrast ratio in the electronic paper apparatus. An object of the present invention is to provide an electronic paper particle additive for electronic paper using carbon black and a particle external additive for electronic paper using carbon black prepared by using the same.

The method for producing an electronic paper particle external additive using carbon black according to the present invention for achieving the above object is to prepare a carbon black having an amino group by reacting by adding nitric acid to a first solvent to which carbon black is added. Amino donating step; And a charge imparting step of adding and reacting ammonia water to the second solvent to which the carbon black having the amino group is added.

In the amino donating step, the first solvent is characterized in that the acetic anhydride (acetic anhydride).

In addition, the amino donating step, the reaction solution manufacturing step of adding the carbon black to the first solvent, and then dispersing to prepare a reaction solution; Nitric acid addition step of adding the nitric acid to the reaction solution; And a stirring step of stirring the reaction solution.

In the reaction solution preparation step, the carbon black is 1 to 5 parts by weight based on 100 parts by weight of the first solvent.

In addition, the nitric acid addition step, after maintaining the temperature of the reaction solution at a temperature of 2 ℃ to 15 ℃, characterized in that the nitric acid is added, with respect to 100 parts by weight of the first solvent, the nitric acid is 50 to It is characterized by adding 80 parts by weight.

In addition, the stirring step, the first stirring step of stirring the reaction solution for 4 to 6 hours at a temperature of 2 ℃ to 15 ℃; And a second stirring step of stirring the reaction solution under a temperature of 16 ° C. to 30 ° C. for 4 to 6 hours.

In the charge imparting step, the second solvent is an aqueous sodium hyposulfite solution, wherein the second solvent is 5 wt% to 20 wt% of sodium hyposulfite and 80 wt% to 95 wt% of water. It is characterized by comprising.

In addition, the charge applying step, the reactant manufacturing step of adding a carbon black having the amino group to the second solvent, and then dispersing to prepare a reactant; Ammonia water addition step of adding ammonia water while stirring the reactant; And a reaction step of reacting the reactants by stirring at 15 to 30 ° C. for 15 to 30 hours.

In the reactant manufacturing step, the carbon black having the amino group, based on 100 parts by weight of the second solvent, characterized in that it comprises 2 to 10 parts by weight.

In addition, in the ammonia water addition step, the ammonia water is characterized in that it comprises 15 to 30 parts by weight based on 100 parts by weight of the second solvent.

According to the method for producing an electronic paper particle additive using the carbon black of the present invention and the particle additive for electronic paper using the carbon black prepared by using the same, unlike the conventional method, by using a solution adsorption method, it is more quantitative and uniform. Not only can the functional group be adsorbed to the external additive, but also due to the chemical bonding, there is an advantage that can significantly improve the durability.

In addition, by effectively synthesizing an amino group to carbon black, there is an advantage that can suppress the aggregation between particles and significantly improve the fluidity.

In addition, by reacting carbon black with an amino group with ammonia water and giving sufficient charge to the external additive, a strong charge is formed throughout the particles, thereby increasing the fluidity of the particles and significantly reducing inter-particle interference. There is an advantage.

In addition, by effectively preparing the external additive through the optimum material and its content, it is possible to form chemical bonds simply and economically, and in particular, the external additive enhances the color ratio of the black particles, thereby improving the contrast ratio in the electronic paper apparatus. There is an advantage to this.

1 is a flow chart sequentially showing a manufacturing method of the particle external additive for electronic paper using the carbon black according to the present invention
2 is a cross-sectional view showing that the electronic paper particle additive using the carbon black prepared using the method for preparing an electronic paper particle additive using the carbon black according to the present invention is externally attached to the particle for electronic paper.

Hereinafter, a preferred embodiment of the present invention with respect to a method for producing an electronic paper particle additive using the carbon black according to the present invention and an electronic paper particle additive using the carbon black produced using the same. It demonstrates in detail with reference. The present invention may be better understood by the following examples, which are for the purpose of illustrating the present invention and are not intended to limit the scope of protection defined by the appended claims.

As shown in FIG. 1, the method for preparing an external particle for electronic paper using carbon black according to the present invention is characterized by comprising an amino donating step (S10) and a charging step (S20).

The amino donating step (S10) is a step of preparing carbon black having an amino group by reacting by adding nitric acid to the first solvent to which carbon black is added. This is a step of binding an amino group onto carbon black by reacting a solvent, carbon black and nitric acid.

In the amino donating step (S10), the first solvent may be any solvent that can help the reaction of carbon black and nitric acid, but several experiments, it is most preferable to use acetic anhydride (acetic anhydride) Do. Acetic anhydride acts to uniformly and effectively bind amino groups on the carbon black by reaction between carbon black and nitric acid.

The amino donating step (S10), preferably comprises a reaction solution preparation step (S11), nitric acid addition step (S12) and stirring step (S13).

The reaction solution preparing step (S11) is a step of preparing the reaction solution by adding and dispersing the carbon black to the first solvent. This is a process in which carbon black is dispersed in a solvent phase to increase the reactivity with nitric acid.

Here, it is preferable to add 1-5 weight part of said carbon black with respect to 100 weight part of said 1st solvents, More preferably, it is effective to add 2-3 weight part. If the amount is less than 1 part by weight, the amount of carbon black is excessively low, which causes a problem of inferior reactivity. If the amount is more than 5 parts by weight, it may not be uniformly dispersed in the solvent in an excessive amount relative to the solvent and agglomeration may occur. In the future, there is a problem that the reactivity with nitric acid is lowered.

In addition, the reaction solution production step (S11) is most preferably dispersed by stirring using a stirrer.

Next, nitric acid addition step (S12) is a step of adding the nitric acid to the reaction solution. This is a step of adding nitric acid in order to effectively give amino groups to the carbon black.

In the nitric acid addition step (S12), after maintaining the temperature of the reaction solution at a temperature of 2 ℃ to 15 ℃, it is preferable to add the nitric acid, more preferably at a temperature of 3 ℃ to 7 ℃ Afterwards, it is effective to add the nitric acid. If it is less than 2 ℃, nitric acid is difficult to effectively disperse in the reaction solution at a low temperature, if it exceeds 15 ℃, nitric acid is introduced into the reaction solution at a high temperature immediately reaction occurs, uniformly amino groups on the carbon black There is a problem that cannot be combined.

In addition, in the nitric acid addition step (S12), it is preferable to add 50 to 80 parts by weight, more preferably 60 to 70 parts by weight based on 100 parts by weight of the first solvent. If the amount is less than 50 parts by weight, the nitric acid content is low, and sufficient amino groups cannot be bonded to the carbon black. If the amount is more than 80 parts by weight, the excess amino acid can be formed in the carbon black. Not only that, there is a problem that amino groups are not evenly distributed in carbon black.

The stirring step (S13) is a step of stirring the reaction solution. This is a step for bonding an amino group to carbon black by reacting nitric acid with carbon black in earnest.

The stirring step (S13) is composed of a first stirring step (S131) and a second stirring step (S132).

Here, the first stirring step (S131) is a step of stirring the reaction solution for 4 to 6 hours at a temperature of 2 ℃ to 15 ℃. This is primarily a process for facilitating bonding with carbon black by allowing nitric acid to dissociate in ionic form.

Here, the stirring temperature is preferably 2 ° C to 15 ° C, more preferably 3 ° C to 7 ° C. If the temperature is less than 2 ℃, nitric acid is difficult to dissociate effectively into ionic form at low temperature. If the temperature exceeds 15 ℃, nitric acid dissociates into ionic form at high temperature, the amino group is directly bonded with carbon black. Not only does the amino group not be uniformly bonded to the carbon black, but also the durability of the bond is significantly reduced.

In addition, the stirring time is preferably 4 hours to 6 hours, more preferably 5 hours is effective. If it is less than 4 hours, nitric acid is not sufficiently dissociated in ionic form, and thereafter, reactivity with carbon black is lowered. If it is more than 6 hours, not only economic efficiency is lowered, but also partially dissociated amino groups. By randomly bonding with carbon black, there is a problem that a uniform bond between an amino group and carbon black is not achieved.

Next, the second stirring step (S132) is a step of stirring the reaction solution for 4 to 6 hours at a temperature of 16 ℃ to 30 ℃. This is a reaction process of chemically bonding the dissociated ions with carbon black to produce a carbon black external additive having an amino group bonded thereto.

Here, the stirring temperature is preferably 16 ° C to 30 ° C, more preferably 20 ° C to 25 ° C. If the temperature is less than 16 ° C., the amino group is difficult to be effectively bound to the carbon black, and even if the amino acid is bound, the durability is significantly lowered. If the temperature exceeds 30 ° C., the reaction rate increases rapidly, and thus the amino group is uniformly distributed on the carbon black. There is a problem that is difficult to combine.

In addition, the stirring time is preferably 4 hours to 6 hours, more preferably 5 hours is effective. If it is less than 4 hours, there is a problem that the amino group is not sufficiently bonded to the carbon black. If it exceeds 6 hours, not only the economic efficiency is lowered, but the amino group formed from the carbon black by excessively combining the amino group with the carbon black. There is a problem that it is not evenly distributed.

Both the first stirring step (S131) and the second stirring step (S132) is preferably carried out using a stirrer, the stirring speed of the stirrer is effective to stir slowly to 50 to 200 RPM.

Finally, the drying step (S14) is a step of sufficiently drying after washing the carbon black having the reaction- terminated amino group with excess water, at 15 to 30 ℃ for 24 to 48 hours. This is not an essential step, but it is more preferable to carry out the following charge applying step after drying.

Next, the charging step (S20) is a step of reacting by adding ammonia water to the second solvent to which the carbon black having the amino group is added. This is a reduction reaction, in which a charge is effectively applied to carbon black external particles having an amino group and a chemical bond between the amino group and carbon black is strengthened.

In the charging step (S20), the second solvent may be any solvent effective to impart charge through a reduction reaction without damaging the carbon black having an amino group, but several experiment results show sodium hyposulfite (Sodium Hydrosulfite solutions are most effective.

In addition, the second solvent preferably comprises 5% to 20% by weight of sodium hyposulfite and 80% to 95% by weight of water, and more preferably 15% by weight of sodium hyposulfite and 85% by weight of water. It is effective to comprise a. If it is out of the content ratio range, it is difficult to effectively disperse the carbon black, and there is a problem that the reactivity with ammonia water is also lowered.

The charge imparting step (S20) comprises a reactant manufacturing step (S21), ammonia water addition step (S22) and a reaction step (S23).

The reactant preparing step (S21) is a step of preparing a reactant by adding carbon black having the amino group to the second solvent and then dispersing it. This is a step for preparing carbon reduction in the solvent as a preparation step for the reduction reaction.

In the reactant preparation step (S21), the carbon black having the amino group is preferably included in an amount of 2 to 10 parts by weight, and more preferably 3 to 5 parts by weight, based on 100 parts by weight of the second solvent. to be. If the amount is less than 2 parts by weight, the amount of carbon black is less than that of the solvent, the reaction time is considerably longer, and the economy is inferior. If it is more than 10 parts by weight, the amount of carbon black is higher than the solvent, and the reactivity with ammonia water is high. It is lowered and there exists a problem which is hard to provide a charge sufficiently.

Next, the ammonia water addition step (S22) is a step of adding ammonia water while stirring the reactant. This is a step of injecting ammonia water in order to give a charge to the carbon black through reaction with ammonia water.

In the ammonia water addition step (S22), the ammonia water preferably contains 15 to 30 parts by weight, and more preferably 18 to 24 parts by weight based on 100 parts by weight of the second solvent. If it is less than 15 parts by weight or more than 30 parts by weight, the reactivity between carbon black and ammonia is remarkably poor, and there is a problem that it is difficult to give sufficient charge to the carbon black external additive.

Next, the reaction step (S23) is a step of reacting the reactants by stirring for 15 to 30 hours at 15 to 30 ℃. This is a step of imparting a charge to the carbon black external additive by causing a reaction between ammonia water and carbon black having an amino group, and strengthening the chemical bond between the amino group and the carbon black.

In the reaction step (S23), the reaction temperature is preferably 15 to 30 ℃, more preferably 20 to 25 ℃. If the temperature is less than 15 ℃, there is a problem that the reactivity is significantly lowered due to the low temperature, if the temperature exceeds 30 ℃ excessively fast reaction rather than the chemical bond between the amino group and carbon black is not sufficiently strengthened there is a problem of durability.

In addition, the drying step (S24) is a step of sufficiently drying the carbon black having an amino group subjected to the reduction process with excess water, followed by sufficient drying for 24 to 48 hours at 15 to 30 ℃. This is not an essential step, but is more preferred.

Next, the particle external additive for electronic paper using carbon black prepared according to the present invention, as shown in Figure 2, bare particles (Bare particle) 10, and the external additive particles attached to the bare particles (10) (20), and the chemical bond 30 between the external additive particles 20 and the amino group 40 attached to the external additive particles 20.

This prevents agglomeration as particles for electronic paper through the combination of the external additive particle 20 and the bare particle 10 produced by the present invention, excellent driveability and color implementability, and exhibits an optimum charge. There is an advantage.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is clear that the present invention can be suitably modified and applied in the same manner. Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

Claims (13)

An amino donating step of preparing carbon black having an amino group by reacting by adding nitric acid to a first solvent to which carbon black is added; And
A charge imparting step of adding and reacting ammonia water to the second solvent to which the carbon black having the amino group is added; and a method for producing the particle external additive for electronic paper using carbon black, comprising:
The method of claim 1,
In the amino donating step, the first solvent is an acetic anhydride (acetic anhydride), characterized in that the manufacturing method of the particle external additive for electronic paper using carbon black
3. The method according to claim 1 or 2,
The amino donating step, after the addition of the carbon black to the first solvent, the reaction solution production step of preparing a reaction solution by dispersing;
Nitric acid addition step of adding the nitric acid to the reaction solution; And
Method for producing a particle external additive for electronic paper using a carbon black, characterized in that comprising; a stirring step of stirring the reaction solution;
The method of claim 3, wherein
In the reaction solution manufacturing step, the carbon black is a method for producing an external particle for electronic paper using carbon black, characterized in that 1 to 5 parts by weight based on 100 parts by weight of the first solvent.
The method of claim 3, wherein
In the nitric acid addition step, after maintaining the temperature of the reaction solution at a temperature of 2 ℃ to 15 ℃, the nitric acid is added to the method for producing an electronic paper particle additive for electronic paper using carbon black.
The method of claim 3, wherein
In the nitric acid addition step, with respect to 100 parts by weight of the first solvent, the production method of the particle external additive for electronic paper using carbon black, characterized in that 50 to 80 parts by weight of the silver nitrate is added.
The method of claim 3, wherein
The stirring step, the first stirring step of stirring the reaction solution for 4 to 6 hours at a temperature of 2 ℃ to 15 ℃; And
A second stirring step of stirring the reaction solution for 4 to 6 hours at a temperature of 16 ℃ to 30 ℃; manufacturing method of the particle external additive for electronic paper using a carbon black, characterized in that
The method of claim 1,
In the charge applying step, the second solvent is a sodium hyposulfite aqueous solution, characterized in that the manufacturing method of the particle external additive for electronic paper using carbon black
The method of claim 8,
The second solvent is 5 to 20% by weight of the sodium hyposulfite and 80% to 95% by weight of water, the method for producing an electronic paper particle additive using the carbon black, characterized in that
The method according to claim 1 or 8,
The charge imparting step may include adding a carbon black having the amino group to the second solvent, and then dispersing the reactant to prepare a reactant;
Ammonia water addition step of adding ammonia water while stirring the reactant; And a reaction step of reacting the reactants by stirring for 15 to 30 hours at 15 to 30 ° C .;
The method of claim 10,
In the reactant manufacturing step, the carbon black having the amino group with respect to 100 parts by weight of the second solvent, 2 to 10 parts by weight of the method for producing an electronic paper particle external additive using carbon black, characterized in that
The method of claim 10,
In the ammonia water addition step, with respect to 100 parts by weight of the second solvent, the ammonia water comprises 15 to 30 parts by weight of a method for producing an electronic paper particle additive using carbon black, characterized in that Particle external additive for electronic paper using carbon black, characterized in that prepared by claim 1 or 2

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