KR20120117249A - Particle external additive for e-paper for composite surface treatment using carbonblack,sio2 and particle for e-paper treated composite surface using thereof - Google Patents

Abstract

PURPOSE: A particle external additive for electronic paper for composite surface treatment using carbon black and SiO2 and a particle for electronic paper thereof are provided to combine carbon black with silicon dioxide, thereby placing the carbon black combined with the silicon dioxide on a surface of a particle. CONSTITUTION: A plurality of carbon black particles(20) are added externally to a bare particle. A plurality of silicon dioxide particles(40) are added externally to the carbon black particles. The carbon black particles are evenly distributed on a surface of the bare particle. The silicon dioxide particles are evenly distributed on a surface of the carbon black particles. The silicon dioxide particles are not close to the bare particle and are placed between the carbon black particles.

Description

Particles for Electronic Paper for Composite Surface Treatment Using Carbon Black and Silicon Dioxide and Particles for Electronic Surface Treated with Composite Surface Using the Same {PARTICLE EXTERNAL ADDITIVE FOR E-PAPER FOR COMPOSITE SURFACE TREATMENT -PAPER TREATED COMPOSITE SURFACE USING THEREOF}

The present invention relates to a particle additive for electronic paper for composite surface treatment using carbon black and silicon dioxide, and to an electronic paper particle complexed with the surface using the same. More specifically, unlike the conventional art, By forming the surface in a multilayer structure using a composite material, it not only prevents agglomeration between particles, but also significantly improves durability and fluidity, and is an electronic paper particle additive for composite surface treatment using carbon black and silicon dioxide. And it relates to a composite surface treated particles for electronic paper 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 agglomeration of fluidized particles, development of a method of solving such problems by modifying the external additive itself is required.

In addition, by effectively constructing a multi-layered external additive on the surface of the fluid particles, combining them uniformly chemically rather than physically, and adding a multi-layered external additive to optimize the particle structure, Development is required.

The present invention is to solve the above problems, unlike the prior art, by combining carbon black and silicon dioxide having an amino group and externally added to the particle surface, carbon black and dioxide which can suppress the aggregation between particles and significantly improve the fluidity An object of the present invention is to provide an electronic paper particle additive for a composite surface treatment using silicon and an electronic paper particle treated with the composite surface using the same.

In addition, since carbon black and silicon dioxide are complex and positioned on the particle surface, unlike the conventional external additives, the voids of the external additives are eliminated on the particle surface, thereby maximizing the effect of agglomeration and fluidity improvement between particles due to amino groups. An object of the present invention is to provide an electronic paper particle additive for composite surface treatment using carbon black and silicon dioxide, and particles for composite surface treatment using the same.

In addition, by using carbon black and silicon dioxide in combination, particles of electronic paper for composite surface treatment using carbon black and silicon dioxide, which can improve the overall particle performance of the electronic paper device due to the external properties of both materials, An object of the present invention is to provide additives and particles for composite surface treatment using the same.

In addition, it is a particle structure in which the external additive is distributed without voids on the particle surface, and the original particle color is maximized by the external additive, and the electron for the composite surface treatment using carbon black and silicon dioxide which can improve the contrast ratio in the electronic paper device An object of the present invention is to provide a particle external additive for paper and particles for composite surface treatment using the same.

In addition, by reacting ammonia water with the external additives to give sufficient charge to the external additives, a strong charge is formed throughout the particles, thereby increasing the fluidity of the particles and significantly reducing the interference between particles. And it is an object of the present invention to provide an electronic paper particles external additive for the composite surface treatment using silicon dioxide and the composite surface-treated electronic paper particles using the same.

In addition, by effectively preparing the external additive through the optimum material and its content, the particle additive for electronic paper for complex surface treatment using carbon black and silicon dioxide which enables simple and economical chemical bond formation with particles and uses the same It is an object to provide a composite surface treated particles for electronic paper.

Particle external additive for electronic paper for composite surface treatment using carbon black and silicon dioxide according to the present invention for achieving the above object, characterized in that comprises a carbon black having an amino group and silicon dioxide having an amino group And at least one of ammonia water or a solvent.

The silicon dioxide having the amino group may include 50 to 200 parts by weight based on 100 parts by weight of the carbon black having an amino group, and the ammonia water may be 300 to about 100 parts by weight of the carbon black having the amino group. It is characterized by including 1500 parts by weight.

In addition, the solvent comprises 5% to 20% by weight of sodium hyposulfite and 80% to 95% by weight of water, and the solvent is 1000 to 100 parts by weight of carbon black having the amino group. It is characterized by including 5000 parts by weight.

Next, the composite surface-treated electronic paper particles according to the present invention, the bare particles; A plurality of carbon black particles attached to the bare particles; And a plurality of silicon dioxide particles externally attached to the carbon black particles.

The carbon black particles are evenly distributed on the surface of the bare particles, wherein the silicon dioxide particles are evenly distributed on the surface of the carbon black particles, do not contact the bare particles, between the carbon black particles It is characterized in that the location.

In addition, the size of the bare particles is characterized in that 5㎛ to 20㎛, the bare particles, characterized in that comprises a monomer, a polymerization initiator and an ionic monomer.

The monomer is at least one of methyl methacrylate, ethylene terephthalate, styrene sulfonate, vinyl acetate, methyl styrene, acrylic acid, butyl methacrylate, ethyl methacrylate, 2-ethylhexyl acrylate or N-vinyl caprolactam Wherein the polymerization initiator is at least one of a peroxide compound or an azo compound, and the ionic monomer is any one of styrene sulfonic acid or [2- (methacryloxy) ethyl] trimethyl ammonium chloride. It is done.

In addition, at least one of the carbon black particles or the silicon dioxide particles is characterized in that the amino group is bonded, the size of the carbon black particles and the silicon dioxide particles are characterized in that the 0.01 ㎛ to 0.7 ㎛, the bare particles And the carbon black particles and the silicon dioxide particles have the same charge.

According to the electronic additive particle external additive for the composite surface treatment using the carbon black and silicon dioxide of the present invention and the composite surface treated electronic paper particle using the same, unlike the conventional art, a composite of carbon black and silicon dioxide having an amino group By externally attaching to the particle surface, there is an advantage that can suppress the aggregation between particles and significantly improve the fluidity.

In addition, since carbon black and silicon dioxide are complex and positioned on the particle surface, unlike the conventional external additives, the voids of the external additives are eliminated on the particle surface, thereby maximizing the effect of agglomeration and fluidity improvement between particles due to amino groups. There is an advantage.

In addition, by using a combination of carbon black and silicon dioxide, there is an advantage that can improve the overall particle performance in the electronic paper device due to the external properties of both materials.

In addition, as a particle structure in which the external additive is distributed without voids on the particle surface, the original particle color is maximized due to the external additive, thereby improving the contrast ratio in the electronic paper apparatus.

In addition, by reacting ammonia water with the external additives to give sufficient charge to the external additives, a strong charge is formed throughout the particles, thereby increasing the fluidity of the particles and significantly reducing the interference between particles. have.

In addition, by effectively preparing the external additives through the optimum material and its content, there is an advantage that it is possible to form chemical bonds with the particles simply and economically.

1 is a cross-sectional view showing the particles for the composite surface treatment of the present invention by the present invention

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of the present invention for an electronic paper particle external additive for a composite surface treatment using carbon black and silicon dioxide according to the present invention and a composite surface treated electronic paper particle using the same It will be described in detail with reference to. The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

First, the particle external additive for electronic paper for the composite surface treatment using carbon black and silicon dioxide according to the present invention is characterized by comprising carbon black having an amino group and silicon dioxide having an amino group.

It is preferable to further contain at least one of aqueous ammonia or a solvent here.

The carbon black having an amino group and the silicon dioxide having an amino group have excellent characteristics of preventing particle aggregation and fluidity due to the bound amino group, and this is due to the chemistry between the particles having amino groups through constant research. It has been found that the aggregation of liver is suppressed and the flow characteristic is increased, and this is applied to the present invention.

In addition, the silicon dioxide having the amino group preferably contains 50 to 200 parts by weight, more preferably 80 to 120 parts by weight, most preferably 100 parts by weight based on 100 parts by weight of the carbon black having an amino group. It is effective.

If the content is less than 50 parts by weight, the content of silicon dioxide particles is less than that of carbon black particles, so that the entire surface of the particles may not be covered, and the particle characteristics such as fluidity may be significantly reduced. In addition to the economical fall in content, there is a problem that the fluidity is lowered due to the increase in particle size.

In addition, the ammonia water serves to enhance the fluidity of the particles by applying an electric charge to the external additive, the ammonia water preferably contains 300 to 1500 parts by weight based on 100 parts by weight of carbon black having the amino group. More preferably, it is effective to include 600 to 1000 parts by weight. If it is less than 300 parts by weight, it is difficult to give sufficient charge to the external additive, and if it exceeds 1500 parts by weight, economical efficiency is lowered, and there is a problem that charge imbalance between the particles and the external additive occurs.

Preferably, the solvent 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. effective. If it is out of the content ratio range, it is difficult to effectively disperse carbon black and silicon dioxide, and there is a problem that the reactivity with ammonia water is also lowered.

Moreover, it is preferable that the said solvent contains 1000-5000 weight part with respect to 100 weight part of carbon black which has the said amino group, More preferably, it is effective to contain 2000-3000 weight part. If it is less than 1000 parts by weight, there is a problem that the carbon black and silicon dioxide particles are difficult to be uniformly bonded to the particle surface due to the dispersibility of carbon black and silicon dioxide particles. If the amount is more than 5000 parts by weight, the carbon black and silicon dioxide particles are diluted to an excessive amount. There is a problem that agglomeration does not occur evenly distributed on the surface.

Next, the manufacturing method of the particle external additive for electronic paper for the composite surface treatment by this invention comprises the method of manufacturing carbon black which has an amino group, and the method of manufacturing silicon dioxide which has an amino group.

First, the method for producing carbon black having an amino group is characterized by comprising an amino donating step (S10) and a charge adding 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 method for producing silicon dioxide having an amino group according to the present invention is characterized in that it comprises a purification step (S30) and the amino group substitution step (S40).

The purification step (S30) is a step of purifying silicon dioxide by heat treatment at 300 to 500 ℃ for 15 to 30 hours. This is a heat treatment process that effectively removes and purifies moisture and impurities in silicon dioxide without damaging silicon dioxide.

In addition, the heat treatment temperature is preferably 300 to 500 ° C, more preferably 350 to 450 ° C. If it is less than 300 ℃ there is a problem that the moisture and impurities are not sufficiently purified, if it exceeds 500 ℃ there is a problem that may cause damage to the silicon dioxide itself.

The heat treatment time is preferably 15 to 30 hours, more preferably 20 to 25 hours. If less than 15 hours, there is a problem that can not be sufficiently purified, if more than 30 hours there is a problem that not only the economical efficiency, but also damage to silicon dioxide.

Here, by using silicon dioxide as an external additive of the particles for electronic paper, silicon dioxide can implement a variety of colors, there is an advantage that can increase the contrast ratio for color particles, as well as white or black particles, Bonding with the particles is easy and durable and effective as an external additive.

Next, the amino group substitution step (S40) is a step of preparing silicon dioxide having an amino group by reacting by adding the silicon dioxide to the solvent. This is a process for remarkably improving the fluidity of particles and preventing agglomeration by providing amino groups to silicon dioxide.

In the amino group substitution step (S40), the solvent does not interfere with the amino group substitution reaction, any solvent may be any help, in the present invention several times, it is most preferable to use toluene.

In addition, the amino group substitution step (S40), preferably comprises a reaction solution manufacturing step (S41), heating step (S42), ethoxysilane addition step (S43) and stirring step (S44).

First, the reaction solution preparation step (S41) is a step of preparing the reaction solution by adding and dispersing the silicon dioxide in the solvent. This is a reaction preparation process in which silicon dioxide is mixed in an optimum amount in a solvent and then dispersed to facilitate the reaction.

In the reaction solution preparation step (S41), the silicon dioxide is preferably added to 20 to 50 parts by weight, more preferably 30 to 40 parts by weight based on 100 parts by weight of the solvent. If the silicon dioxide is less than 20 parts by weight, the amount contained in the solvent is too small, there is a problem that the substitution reaction of the amino group is inferior, and if it exceeds 50 parts by weight, silicon dioxide is not sufficiently dispersed in the solvent is difficult to effectively react However, there is a problem that a sufficient amino group is not provided to silicon dioxide.

Next, the heating step (S42) is a step of heating the reaction solution under a nitrogen atmosphere. This is a process for creating an effective reaction environment for amino group substitution by maintaining a constant high temperature under a nitrogen atmosphere.

In the heating step (S42), it is preferable to maintain the temperature of the reaction solution at a temperature of 60 ℃ to 90 ℃, more preferably it is effective to maintain a temperature of 70 ℃ to 80 ℃. If it is less than 60 ℃ there is a problem that the reaction between the nitrogen and the reaction solution is difficult to occur, and if it exceeds 90 ℃ there is a problem that the reaction solution is difficult to maintain the optimum content ratio due to the high temperature.

In addition, the ethoxysilane addition step (S43) is a step of adding (3-aminopropyl) triethoxysilane ((3-aminopropyl) triethoxysilane) to the reaction solution. This is a step of adding a reactant of a substitution reaction to give an amino group to silicon dioxide particles.

In the ethoxysilane addition step (S43), the (3-aminepropyl) triethoxysilane is preferably 20 to 50 parts by weight, and more preferably 30 to 40 parts by weight based on 100 parts by weight of the solvent. effective. If it is less than 20 parts by weight, there is a problem that a sufficient amino group is difficult to be imparted to the silicon dioxide phase, and if it exceeds 50 parts by weight, it is difficult to uniformly distribute an appropriate amount of amino groups imparted to the silicon dioxide phase, rather the fluidity of particles is lowered. There is a problem.

Finally, the stirring step (S44) is a step of stirring the reaction solution. This is a process of reacting (3-aminepropyl) triethoxysilane with silicon dioxide under a nitrogen atmosphere.

In the stirring step (S44), the reaction solution is preferably stirred for 15 to 30 hours at a temperature of 60 ℃ to 90 ℃, more preferably for 20 to 25 hours at a temperature of 70 ℃ to 80 ℃ Is effective. If the temperature is lower than 70 ° C., the temperature is low, and the reactivity decreases, thereby making it difficult to sufficiently bond the amino group to silicon dioxide. If the temperature is higher than 90 ° C., the reaction rate is increased, but the amino group is uniformly bonded to silicon dioxide. It is difficult to achieve, and there is a problem that the reactants are damaged.

In addition, after the stirring step (S44) is not an essential step, it is preferable to add a drying step (S45).

Drying step (S45) is divided into a step of washing the silicon dioxide having the reaction- terminated amino group with toluene and after washing, the step of sufficiently drying at 15 to 30 ℃ for 24 to 48 hours. First, by washing, by removing the unreacted material, thereby improving the external reactivity to the particles, and serves to facilitate the subsequent particle surface treatment process through the drying process.

Next, as shown in FIG. 1, the composite surface-treated electronic paper particles of the present invention include bare particles 10 and a plurality of carbon black particles 20 externally attached to the bare particles 10. And it characterized in that it comprises a plurality of silicon dioxide particles 40 attached to the carbon black particles (20).

The bare particles 10 are preferably black particles because they match the color of the carbon black particles of the present invention. However, the bare particles 10 are not necessarily limited to black particles, and the color may be matched with an external additive with a pigment or the like.

In addition, the size of the bare particles 10 is preferably 5㎛ 20㎛, more preferably 7㎛ 10㎛. If the particle size is less than 5 μm, the particle size is small, and the particle driving efficiency of the electronic paper device is lowered. If the particle size exceeds 20 μm, the fluidity of the particle is notably reduced, and the resolution of the electronic paper device is lowered. there is a problem.

The bare particles 10 may be any one of electronic paper bare particles, but most suitable for the present invention may include a monomer, a polymerization initiator, and an ionic monomer. That is, in the method for producing the bare particles, the monomer, the polymerization initiator, and the ionic monomer are added to the solvent and stirred, whereby the bare particles 10 are preferably synthesized.

Herein, the solvent may be any material that does not interfere with particle synthesis and may help the reaction, but methanol is most preferably used.

In addition, the monomer is methyl methacrylate, ethylene terephthalate, styrene sulfonate, vinyl acetate, methyl styrene, acrylic acid, butyl methacrylate, ethyl methacrylate, 2-ethylhexyl acrylate or N-vinyl caprolactam It is preferable to use at least one, and the above materials may be copolymerized.

The polymerization initiator may use any free radical polymerization initiator capable of triggering an emulsion-free polymerization, but in the present invention, at least one of a peroxide compound or an azo compound is preferable, and the peroxide compound is, in principle, an inorganic peroxide, For example alkyl hydroperoxides, examples being tert-butyl, p-mentyl and cumyl hydroperoxide, and also dialkyl or diaryl peroxides such as di-tert-butyl peroxide or dicumyl peroxide Azo compounds are mainly 2,2'-azobis (isobutylonitrile), 2,2'-azobis (isobutyramidine) hydrochloride (2,2'-azobis (isobutyramidine) hydrochloride) It is most efficient to use 'AIBN') as a polymerization initiator.

In addition, the ionic monomer is preferably either styrene sulfonic acid or [2- (methacryloxy) ethyl] trimethyl ammonium chloride. Here, styrene sulfonic acid serves to impart a negative charge to the bare particles, and [2- (methacryloxy) ethyl] trimethyl ammonium chloride serves to impart a (+) charge to the bare particles. Styrene sulfonic acid or [2- (methacryloxy) ethyl] trimethyl ammonium chloride is very effective in the present invention because it is easy to synthesize particles and can impart an appropriate amount of charge.

In addition, the carbon black particles 20 is preferably evenly distributed on the surface of the bare particles (10). Evenly distributed throughout the bare particles 10 to maximize the effect of the amino group and the performance improvement due to the external additive.

In addition, the silicon dioxide particles 40 are evenly distributed on the surface of the carbon black particles 20, and are not disposed in contact with the bare particles 10, and are located between the carbon black particles 20. That is, as shown in Figure 1, due to the structure in which the silicon dioxide particles 40 effectively bonded to the pores between the carbon black particles 20, by the external additive is distributed without a blank space between the bare particles 10 and the outside, Not only can the effect of the amino group and the performance improvement effect due to external additives be maximized, but the bare particles 10, the carbon black particles 20, and the silicon dioxide particles 40 are all composed of the same color, so that the contrast ratio of the electronic paper device. In addition, there is an advantage that can be significantly increased unlike when added to the conventional external additives.

In addition, at least one of the carbon black particles 20 or the silicon dioxide particles 40 is preferably an amino group is bonded. As described above, there is an advantage that the properties in the electronic paper of the particles are remarkably improved by binding an amino group.

In addition, the size of the carbon black particles 20 and the silicon dioxide particles 40 is preferably 0.01㎛ to 0.7㎛, more preferably 0.1㎛ to 0.3㎛. If it is less than 0.01 μm, there is a problem that it is difficult to control the distribution on the particle surface evenly. If it exceeds 0.7 μm, it is excessively large compared to the size of the bare particles 10, and rather, there may be a problem that disturbs particle behavior. In addition, there is a problem of lowering the resolution of the electronic paper apparatus.

In addition, the bare particles 10, the carbon black particles 20, and the silicon dioxide particles 40 are connected to each other by a chemical bond, and in particular, a strong chemical bond 30 is formed between the bare particles 10 and the carbon black particles 20. Is done.

Unlike the related art, as shown above, due to the strong chemical bonding by the chemical reaction between the bare particles 10 and the carbon black particles 20 and the silicon dioxide particles 40, the durability is remarkably improved, whereby the bare particles 10 ), The carbon black particles 20 and the silicon dioxide particles 40 may all have the same charge.

That is, they may be all positive charges or all negative charges. Thus, unlike the prior art, even if composed of the same charge, since the durability does not decrease by strong bonding, the same charge can be applied.

Therefore, by configuring the charges of the bare particles 10, the carbon black particles 20 and the silicon dioxide particles 40 in the same way, it is possible to significantly prevent agglomeration between the particles for electronic paper and to provide excellent driving characteristics. have.

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 (15)

Particle external additive for electronic paper for composite surface treatment using carbon black and silicon dioxide, comprising carbon black having amino group and silicon dioxide having amino group
The method of claim 1,
Particle additive for electronic paper for composite surface treatment using carbon black and silicon dioxide, characterized in that it further comprises at least one of ammonia water or a solvent
3. The method according to claim 1 or 2,
Particle additive for electronic paper for composite surface treatment using carbon black and silicon dioxide, characterized in that the silicon dioxide having the amino group comprises 50 to 200 parts by weight based on 100 parts by weight of the carbon black having an amino group
The method of claim 2,
With respect to 100 parts by weight of the carbon black having the amino group, the ammonia water includes 300 to 1500 parts by weight of the electronic paper particle additive for the composite surface treatment using carbon black and silicon dioxide
The method of claim 2,
The solvent is an external particle for the electronic paper for the composite surface treatment using carbon black and silicon dioxide, characterized in that containing 5% to 20% by weight of sodium hyposulfite and 80% to 95% by weight of water
The method of claim 2,
With respect to 100 parts by weight of the carbon black having the amino group, the solvent is an electronic paper particle additive for the composite surface treatment using carbon black and silicon dioxide, characterized in that containing 1000 to 5000 parts by weight
Bare particles;
A plurality of carbon black particles attached to the bare particles; and
The composite surface-treated electronic paper particles comprising a; a plurality of silicon dioxide particles attached to the carbon black particles; 8. The method of claim 7,
The carbon black particles are composite surface-treated electronic paper particles, characterized in that evenly distributed on the surface of the bare particles
9. The method according to claim 7 or 8,
The silicon dioxide particles are evenly distributed on the surface of the carbon black particles, do not contact the bare particles, and is located between the carbon black particles, composite surface treated electronic paper particles, characterized in that
9. The method according to claim 7 or 8,
The size of the bare particles is a composite surface treated electronic paper particles, characterized in that 5㎛ to 20㎛
9. The method according to claim 7 or 8,
The bare particles, the composite surface-treated electronic paper particles, characterized in that it comprises a monomer, a polymerization initiator and an ionic monomer. 12. The method of claim 11,
The monomer is at least one of methyl methacrylate, ethylene terephthalate, styrene sulfonate, vinyl acetate, methyl styrene, acrylic acid, butyl methacrylate, ethyl methacrylate, 2-ethylhexyl acrylate or N-vinyl caprolactam Wherein the polymerization initiator is at least one of a peroxide compound or an azo compound, and the ionic monomer is any one of styrene sulfonic acid or [2- (methacryloxy) ethyl] trimethyl ammonium chloride. Composite surface treated electronic paper particles
9. The method according to claim 7 or 8,
At least one of the carbon black particles or the silicon dioxide particles is a composite surface-treated electronic paper particles, characterized in that the amino group is bonded
9. The method according to claim 7 or 8,
The size of the carbon black particles and the silicon dioxide particles is a composite surface-treated electronic paper particles, characterized in that 0.01 ㎛ to 0.7 ㎛
9. The method according to claim 7 or 8,
The bare particles, the carbon black particles and the silicon dioxide particles are composite surface-treated electronic paper particles, characterized in that the same charge

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