TWI434860B - Synthesis and Application of Novel Amphoteric Monomers, Their Synthesis, and Their Derivative Amphoteric Copolymer and Copolymer - Google Patents

Description

Novel amphoteric monomer, synthesis thereof, and amphoteric copolymer derived therefrom and preparation and application of the copolymer

The present invention relates to an amphoteric monomer having the structural formula (1), and an amphoteric copolymer thereof, and particularly, to an amphoteric copolymer having the structural formula (2), a preparation method thereof and a ceramic powder slurry thereof The use of bulk dispersants.

Ceramic powders such as barium titanate and lead zirconate titanate are widely used in the electronics industry. For example, capacitors, inductors, and thermistors can be fabricated using barium titanate as a raw material. In the process, barium titanate powder must be added to the solvent to form a slurry. Currently, the solvent used in the industry is divided into water and organic solvents. Based on environmental protection and cost reduction, in recent years, efforts have been made to develop a water system casting system. .

The dispersion effect of the ceramic powder in the solvent has a great influence on the process quality. After the slurry with poor dispersibility is dried, the density of the green embryo is small, and the sintered embryo body has a large porosity and is easily broken, resulting in low product yield and poor electrical properties. Therefore, it is often necessary to add a dispersing agent to the ceramic slurry in the industry to facilitate the subsequent process and obtain a good quality product. In the case of an aqueous ceramic powder slurry, an acrylic-based polymer or copolymer is often used in the industry as a dispersing agent, and a typical example is polyammonium methacrylate (PMAAN). In recent years, there have been many studies on dispersants using PMAAN or acrylic acid-derived polymers as ceramic powders such as barium titanate, alumina, zirconia, titania, etc., although the results show that PMAAN or acrylic acid-derived polymers exhibit good dispersion effects. But there is still much room for improvement; for example, with PMAAN As the dispersant barium titanate slurry, the amount of barium ions eluted is excessive; the excess barium ions are eluted and re-deposited on the surface of the ceramic powder during the drying process, which has a negative influence on the electrical properties of the sintered body.

In recent years, the electronics industry has developed rapidly, and the market demand for electronic ceramics is increasing. Taking barium titanate as an example, it has high dielectric properties and is an important raw material for capacitor manufacturing. At present, the demand for electronic components tends to be light, thin, short, small and functional, and multilayer ceramic capacitors (MLCC) have become the mainstream in the market. In order to obtain a product with a large number of dielectric layers, high capacitance and small volume, the dielectric layer must be thin and dense. Therefore, how to prepare a slurry with high solid content and good dispersion is an important link, so that the dispersant is widely used in various ceramics. Dispersion of the powder. Most of the ceramic powder dispersant is a polymer type interface auxiliaries. The dispersant is dispersed in the slurry and adsorbed on the surface of the powder to achieve the purpose of dispersing particles. After the dissociation of the charged functional group of the dispersant is adsorbed on the surface of the powder, many polymer additives are adsorbed on the surface of the powder, and they have the same charge, which reduces the aggregation of the particles due to the charge repulsion; another dispersion mechanism is adsorbed on the surface of the particles. The polymer additive produces a stereoscopic barrier to achieve dispersion of the powder.

At present, commercial dispersants are mostly polyacrylic acid series dispersants, among which polymethacrylates and acrylic acid-derived polymers are well known, and many related papers have been published in the academic field. This type of auxiliaries is used as a ceramic powder dispersant. Although the dispersion effect is good, there is still room for improvement. For example, the powder has a high sedimentation rate and a large amount of cerium ions. The excess cerium ion dissolution will affect the electrical properties of the sintered body. Or other properties have a negative impact. The novel dispersant improves the above disadvantages and achieves uniform dispersion of the slurry.

It is an object of the present invention to provide an amphoteric monomer of the following formula (1): Wherein R ₁ is H, C _x H _2x+1 , x is an integer from 1 to 5, and R ₂ is H, NH ₄ ⁺ or an alkali metal ion.

Another object of the present invention is to provide a process for the preparation of the amphoteric monomer comprising sodium chloroacetate and N-(4-vinylphenyl)-N,N-dimethylamine or N-(4-α -C1-C5-Alkyl-vinylphenyl)-N,N-dimethylamine reaction.

Another item of the present invention is to provide an amphoteric copolymer of the formula (2)

Wherein R ₁ is H, C _x H _2x+1 , x is an integer from 1 to 5, R ₂ is H, NH ₄ ⁺ or an alkali metal ion; m is an integer from 10 to 1000, and n is an integer from 10 to 1000; R is an acrylic acid, acrylamide, methacrylic acid, methacrylamide or a combination of the foregoing and a derivative thereof, and is a starting comonomer.

Another item of the present invention is a method for preparing the water-soluble amphoteric copolymer, comprising the amphoteric monomer and the starting comonomer in a reaction vessel, Ammonium persulfate was used as a starting agent, sodium methacrylate sulfonate was used as a chain transfer agent, and an aqueous solution was reacted under nitrogen and a constant temperature system. Finally, the water-soluble amphoteric copolymer was separated by solvent extraction.

Another object of the present invention is to provide the use of the water-soluble amphoteric copolymers as a ceramic powder slurry dispersant, which can reduce the viscosity of a ceramic powder slurry such as barium titanate slurry and reduce the aggregation of powder particles. And the time of increasing the particle suspension has a good dispersion effect on the barium titanate slurry. In addition, the addition of the amphoteric copolymer of the present invention can reduce the amount of cerium ions eluted in the barium titanate slurry, and the improvement of the addition of PMAAN increases the disadvantage of the strontium ion elution amount in the barium titanate slurry, thereby improving the dielectric of the sintered body. The value simultaneously reduces the dielectric loss value.

Accordingly, another object of the present invention is to provide a ceramic powder slurry comprising the above-described amphoteric copolymer of the present invention, which is dissolved in water and added to a ceramic powder to form a slurry, which can reduce the ceramic powder slurry. Viscosity.

Detailed description of preferred embodiments

In one aspect of the invention, an amphoteric monomer having the following formula is provided: Wherein R ₁ is H, C _x H _2x+1 , x is an integer from 1 to 5, and R ₂ is H, NH ₄ ⁺ or an alkali metal ion.

In a preferred embodiment, R ₁ is H, that is, the amphoteric monomer is N-(4-vinylphenyl)-N,N-dimethylglycine or a salt thereof.

In another preferred embodiment, R ₁ is C _x H _2x+1 , and x is an integer from 1 to 5, that is, R ₁ is a C1-C5-alkyl group such as methyl, ethyl, propyl or butyl. Base or pentyl. The amphoteric monomer is N-(4-α-C1-C5-alkyl-vinylphenyl)-N,N-dimethylglycine or a salt thereof.

In the amphoteric monomer of the formula (1), R ₂ is H, NH ₄ ⁺ or an alkali metal ion, that is, the amphoteric monomer of the formula (1) may be in an acid form or a salt form. The salt can be an ammonium salt or an alkali metal salt such as a sodium or potassium salt.

Hereinafter, for the sake of simplicity, the present invention is illustrated by the N-(4-vinylphenyl)-N,N-dimethylglycine representing the amphoteric monomer of the formula (1).

In another aspect of the invention, there is provided a process for the preparation of an amphoteric monomer of formula (1) which comprises reacting the reactant sodium chloroacetate with N-(4-vinylphenyl)-N,N-dimethylamine or N-(4-α-C1-C5-alkyl-vinylphenyl)-N,N-dimethylamine has a molar ratio of 1:1 in both, a reaction temperature of 60-90 ° C, and a constant reaction time The reaction is carried out under conditions of 8-16 hours, etc., and then the obtained product is extracted with a solvent, wherein the extraction solvent is preferably acetone or methanol.

The amphoteric single system of formula (1) was identified by ¹ H-NMR and IR spectroscopy. The ¹ H-NMR spectrum thereof is shown in Fig. 1. There are resonance peaks at δ = 7.4 - 7.7, 6.8 - 6.9, 5.9 - 6.0, 5.4 - 5.5, 4.7, 3.7 - 3.8, and 3.2 ppm, respectively. IR spectrum shown in Figure 2, respectively, ^{3200-3600cm -1, 1680cm -1, 1650cm -1} , 1595cm -1, 1398cm -1, 887cm ^-1, and the absorption peak.

In another aspect, the present invention provides an amphoteric copolymer having the following general formula (2): Wherein R ₁ may be H, C _x H _2x+1 , x is an integer from 1 to 5, R ₂ may be H, NH ₄ ⁺ or an alkali metal ion; m is an integer from 10 to 1000, and n is from 10 to 1000 An integer: R is a polymerization unit derived from acrylic acid, acrylamide, methacrylic acid, methacrylamide or a combination of the foregoing and derivatives thereof, that is, an initial co-monomer.

In the formula (2), R is preferably acrylamide, methacrylamide, acrylic acid, methacrylic acid or a derivative thereof such as an ester or a salt, or a combination of any of the foregoing. Aggregation unit.

Accordingly, in another aspect, the present invention provides an amphoteric copolymer which is a poly(N-(4-vinylphenyl)-N,N obtained by polymerization of an amphoteric monomer of the present invention and methacrylic acid. a water-soluble amphoteric copolymer of -dimethylglycine/methacrylate (PVM).

In another aspect of the present invention, the present invention provides an amphoteric copolymer which is a poly(N-(4-) obtained by polymerizing an amphoteric monomer with a (meth) acrylate and a (meth) acrylamide. A water-soluble amphoteric copolymer of vinylphenyl)-N,N-dimethylglycine/(meth)acrylamide/(meth)acrylate) (PVMM).

These copolymers were identified by ¹ H-NMR and IR spectroscopy. As explained in the examples below.

In another aspect, the present invention provides a process for preparing the water-soluble amphoteric copolymer of the present invention, comprising the amphoteric monomer and the starting comonomer in a reaction vessel, using ammonium persulfate as a starting agent, Sodium methacrylate sulfonate is used as a chain transfer agent, and an aqueous solution is reacted under a nitrogen gas and a constant temperature system.

In the preparation method of the present invention, it is essentially a radical initiation polymerization reaction, and the initiator used is preferably potassium persulfate or ammonium persulfate; wherein the chain transfer agent used for adjusting the molecular weight is preferably A. Sodium propylene sulfonate; the reaction temperature is preferably 60-90 ° C; the constant temperature reaction time is 6-10 hours; and the extraction solvent of the obtained product is preferably acetone or methanol.

Another object of the present invention is to provide the use of the water-soluble amphoteric copolymers as a ceramic powder slurry dispersant, which can reduce the viscosity of a ceramic powder slurry such as barium titanate slurry and reduce the aggregation of powder particles. And the time of increasing the particle suspension has a good dispersion effect on the barium titanate slurry. In addition, the addition of the amphoteric copolymer of the present invention can reduce the amount of cerium ions eluted in the barium titanate slurry, and the improvement of the addition of PMAAN increases the disadvantage of the strontium ion elution amount in the barium titanate slurry, thereby improving the dielectric of the sintered body. The value simultaneously reduces the dielectric loss value.

Accordingly, in another aspect, the present invention provides a ceramic powder slurry comprising the above-described amphoteric copolymer of the present invention, which is dissolved in water and added to a ceramic powder to form a slurry to reduce the ceramic powder slurry Viscosity.

In the ceramic powder slurry of the present invention, the ceramic powder comprises barium titanate, alumina and titania.

In the ceramic powder slurry of the present invention, the addition amount of the amphoteric copolymer is Between 0.05 and 1.0% by weight.

In a preferred embodiment, the ceramic powder is barium titanate, and wherein the ceramic powder has a lower amount of cerium ions eluted than the ceramic powder slurry to which the amphoteric copolymer is not added.

In a preferred embodiment, the ceramic powder slurry is characterized in that its viscosity is lower than that of a ceramic powder slurry to which the amphoteric copolymer is not added, and its stability is superior to that of a ceramic powder slurry to which the amphoteric copolymer is not added. The powder particle size is smaller than the ceramic powder slurry to which the amphoteric copolymer is not added.

In a preferred embodiment, the ceramic powder slurry containing the amphoteric copolymer is characterized in that after the slurry is ball milled, the sample is dried, ground into a powder, sieved, and pressed into a disk shape. After the obtained sample is sintered at a constant temperature of 1000-1300 ° C for 4-8 hours, the dielectric constant value of the obtained sintered body is higher than that of the sintered body to which the amphoteric copolymer is not added, and the dielectric loss value is lower than that of the amphoteric copolymer not added. Sintered body.

The following examples are intended to be illustrative of the invention, and are not intended to limit the scope of the invention.

Embodiment 1

Dissolve 0.3 mol of sodium chloroacetate in 200 g of deionized water and place it in a four-necked reaction flask with 0.3 mol of N-(4-vinylphenyl)-N,N-dimethylamine to 1 N HCl Adjust the pH of the solution to 3, pass nitrogen for 1 hour, and continue to react at 70 ° C for 12 hours. The obtained product is concentrated by swirling to remove most of the solvent, and then extracted with a large amount of acetone. After purification, it is placed in an oven at 85 ° C for 2 hours to remove. Residual acetone, finally get about 62.5 grams of orange-red viscous liquid N-(4-vinylphenyl)-N,N-dimethylglycine, 75% yield.

The ¹ H-NMR spectrum of N-(4-vinylphenyl)-N,N-dimethylglycine (VBDMGly) is shown in Figure 1, at δ = 7.4 - 7.7, 6.8 - 6.9, 5.9, respectively. There are resonance peaks at -6.0, 5.4-5.5, 4.7, 3.7-3.8, and 3.2 ppm. IR spectrum shown in Figure 2, respectively, ^{3200-3600cm -1, 1680cm -1, 1650cm -1} , 1595cm -1, 1398cm -1, 887cm ^-1, and the absorption peak.

Embodiment 2

8.6 g of methacrylic acid was weighed and dissolved in 20 ml of deionized water, and the pH was adjusted to 10 with 1N aqueous ammonia, and stirring was continued for 30 minutes to obtain an aqueous solution of ammonium monomethacrylate. The obtained aqueous ammonium methacrylate solution was placed in a 500 ml four-neck reaction vessel, and 20.5 g of N-(4-vinylphenyl)-N,N-dimethylglycine (VBDMGly) was dissolved in 100 ml. In the ionic water, 1.37 g of ammonium persulfate was added as a starting agent dropwise from the feed tube, and 0.95 g of sodium methacrylate sulfonate was added under nitrogen and constant temperature (70 ° C) system for constant temperature reaction for 8 hours. A viscous liquid product is obtained. The product was naturally cooled to room temperature, purified three times with acetone, filtered off with suction, and placed in an oven at 85 ° C for 2 hours to remove residual acetone to obtain 22.7 g of an orange-red solid product, poly(N-(4-ethylene). Phenyl)-N,N-dimethylglycine/methacrylate (PVM), yield 78%. The structure is as follows:

Figure 3 is a ¹ H-NMR chart of PVM with resonance peaks at δ = 6.8-7.4, 3.5-3.8, 1.5-2.2, and 0.7-1.2 ppm, respectively. FIG 4 is a IR chart of PVM, respectively, ^{2700-3600cm -1, 1656cm -1, 1562cm -1} , 1480cm -1, 1399cm -1, and the absorption peak at 1200cm ^-1.

Embodiment 3

8.6 g of methacrylic acid was weighed and dissolved in 20 ml of deionized water, and the pH was adjusted to 10 with 1N aqueous ammonia, and stirring was continued for 30 minutes to obtain an aqueous solution of ammonium monomethacrylate. The resulting aqueous ammonium methacrylate solution was placed in a 500 ml four-neck reaction vessel. Another two solutions were prepared. Solution 1 was 20.5 g of N-(4-vinylphenyl)-N,N-dimethylglycine dissolved in 100 ml of deionized water; solution 2 was 8.6 g of methacrylamide. In 25.8 grams of deionized water. The first and second solutions were separately added from the feed tube, and 2.05 g of ammonium persulfate was added as a starter. Under nitrogen and a constant temperature (70 ° C) system, 1.42 g of sodium methacrylate sulfonate was added. A viscous liquid product can be obtained by a constant temperature reaction for 8 hours. The product was naturally cooled to room temperature, purified three times with acetone, filtered with suction, and placed in an oven at 85 ° C for 2 hours to remove residual acetone to obtain 24.5 g of an orange solid product, poly(N-(4-ethylene). Phenylphenyl)-N,N-dimethylglycine/methacrylamide/methacrylate (PVMM), yield about 65%. The structure is as follows:

Figure 5 is a ¹ H-NMR chart of PVMM with resonance peaks at δ = 6.6 - 7.5, 3.5 - 3.8, 1.3 - 2.1, and 0.7 - 1.2 ppm, respectively. 6 is the IR chart PVMM, respectively ^{2800-3700cm -1, 3160cm -1, 1709cm -1} , 1547cm -1, 1399cm -1, 1261cm -1, and the absorption peak at 1186cm ^-1.

Embodiment 4

In this embodiment, three different dispersing agents and one barium titanate powder were used to respectively configure the three barium titanate powder aqueous dispersions. The submicron barium titanate powder used was supplied by Xinchang Electronic Ceramics Co., Ltd., the dispersing agent used, two of which were the entities of the present invention, and the other was PMAAN (Darvan C) manufactured by S.T. Vanderbilt.

The dispersion is prepared by adding 3:2 by weight of barium titanate powder and deionized water, and changing the amount of the dispersant added and the weight percentage of the powder is 0.5:1000, 1:1000, 2:1000, 3:1000, 5: 1000, the mixed slurry was adjusted to pH=9, and after ball milling for 24 hours, the relationship between the amount of dispersant added and the viscosity was determined using a Brodfield DV-II viscometer. The experimental results are shown in Figure 7. It can be seen from Fig. 7 that when the dispersant is added in an amount of 2 mg/g BT, the viscosity value is reduced to about 10 mPa·s, which indicates that the addition of PVM and PVMM as a dispersing agent can greatly reduce the viscosity of the barium titanate slurry. The slurry also has good fluidity compared to the PMAAN dispersant.

Embodiment 5

First, the three dispersants were separately dissolved in deionized water, and then barium titanate powder was added; another control experiment was carried out without adding any dispersant, and the three barium titanate solutions were adjusted to pH 9 with 1N sodium hydroxide. In the dispersion liquid configured in this embodiment, the weight percentage of the dispersant to the barium titanate powder is 0.5:1000, 1:1000, 2:1000, 3:1000, 5:1000, respectively, and the water is applied to the barium titanate powder. The weight percentage is 2:3. The configured sample was ball milled for 24 hours, and an appropriate amount of the sample was diluted, and the particle size distribution was measured using a laser particle size analyzer (Mastersizer 2000, Malvern, UK).

It is understood from Fig. 8 that the slurry having no addition of the amphoteric copolymer of the present invention has an average particle diameter ( d ₅₀ ) of 1.15 μm (μm), and the addition of the new PVM and PVMM as a dispersing agent is added in an amount of 2 mg/克 BT (the number of milligrams of dispersant added per gram of barium titanate powder), the minimum average particle size ( d ₅₀ ) of the dispersion is 0.90 and 0.94 μm, respectively, and when PMAAN is added as a dispersant, The minimum average particle size ( d ₅₀ ) of the dispersion is 0.95 μm, which shows that PVM and PVMM have good dispersion effect on the barium titanate particles, and the denser embryo bodies can be accumulated after solvent removal.

Embodiment 6

The dispersion is prepared as a weight ratio of 1:9 barium titanate powder and deionized water, and the amount of the dispersant added and the weight percentage of the powder are changed to 0.5:1000, 1:1000, 1.5:1000, 2:1000, 3: 1000, the mixed slurry was adjusted to pH=9, and after ball milling for 24 hours, the barium titanate slurry was poured into a measuring cylinder, sealed and allowed to stand, and the change in the sedimentation height was observed.

Figures 9 and 10 show the sedimentation of barium titanate slurry with PVM and PVMM. A diagram of the relationship between the volume and the dispersion volume. When the barium titanate slurry is added with no dispersant or PVM or PVMM with 0.5 mg/g BT, the particles are agglomerated, the dispersion is not good, and the sedimentation speed is fast. In one day, most of the particles have settled, and It can be observed that the measuring cylinder is clearly divided into two layers of water and sediment. When the addition amount of PVM and PVMM is more than 2 mg/g BT or more, the dispersion effect is good, and it is found that most of the barium titanate particles are suspended in the measuring cylinder to be turbid, and even after 14 days, most of the particles are not sedimented. Figure 11 is a graph showing the relationship between the settling time and the dispersion volume of the barium titanate slurry to which PMAAN is added. Due to the aggregation of particles, it is easier to settle due to the influence of gravity. It can be seen that the addition of the PVM and PVMM of the present invention as a dispersant for the barium titanate slurry does have a good dispersion effect.

Example 7

The relationship between the amount of the dispersant added and the viscosity of the alumina slurry is carried out using the dispersant of the present invention. The dispersion was prepared by the alumina powder (A21-SG, Alcoa USA) and deionized water in a weight ratio of 3:1, and the amount of the dispersant added and the weight of the powder were changed to 0.5:1000, 1:1000, 2:1000. 3:1000, 5:1000, after ball milling for 24 hours, the relationship between the amount of dispersant added and the viscosity was measured using a Brookfield DV-II viscometer. The experimental results are shown in Fig. 12. It can be seen from Fig. 12 that when the amount of PVM and PVMM added is 2 mg/g BT, the viscosity of the dispersion is reduced to about 69 and 77 mPa·s, respectively. It shows that the addition of PVM and PVMM as dispersant can make the viscosity of alumina slurry. The value is greatly reduced.

Example eight

The relationship between the amount of the dispersant added and the viscosity of the titanium dioxide slurry is carried out using the dispersant of the present invention. Titanium dioxide powder (PT401M, ISK company, Japan) Prepare the dispersion with a weight percentage of deionized water of 5:6, and change the amount of dispersant added and the weight percentage of the powder to 0.5:1000, 1:1000, 2:1000, 3:1000, 5:1000, ball milling for 24 hours. Thereafter, the relationship between the amount of dispersant added and the viscosity was measured using a Brodfield DV-II viscometer, and the experimental results were obtained as shown in Fig. 13. From Fig. 13, it is found that the higher the amount of dispersant added, the lower the viscosity value. When the amount of dispersant added is 3 mg/g BT, the viscosity of the dispersion is reduced to about 17,15 mPa.s, indicating that PVM is added. PVMM as a dispersing agent can reduce the viscosity of the titanium dioxide slurry and have a good dispersion effect.

Example nine

The dispersant of the present invention and the PMAAN dispersant were used to determine the relationship between the amount of different dispersant added and the concentration of cerium ions in the barium titanate suspension. The dispersion is prepared by weighting the powder to deionized water by 3:2, and changing the amount of the dispersant added to the powder by 1:1000, 2:1000, 3:1000, 5:1000, adjusting the mixed slurry to After pH=9, after ball milling for 24 hours, it was centrifuged at 8000 rpm for 60 minutes, and the centrifuged clear liquid was taken for inductively coupled plasma atomic emission spectrometry (ICP-AES, optima 2000 DV, Perkin Elmer Instruments, USA). Measurement. The measurement method is to first ionize the sample with plasma, and after ionizing the sample and then exciting by the light source, atomic emission spectra of various wavelengths can be emitted, and the ion concentration is determined by the intensity of the spectrum.

Figure 14 is a graph showing the relationship between the amount of different dispersants added and the concentration of cerium ions. When PMAAN is used as a dispersing agent, as the amount of dispersant added increases, the amount of slurry cerium ion elution increases, indicating that adding PMAAN as a dispersing agent causes titanic acid. The amount of cesium ion elution increases, while the use of PVM and PVMM as dispersants reduces the concentration of strontium ions in the solution, and the amount of cesium ion eluted does not increase greatly with the addition of the dispersant. It can be seen that the novel dispersant of the present invention can inhibit the elution of cerium ions from the surface of barium titanate particles, which greatly contributes to the electrical properties of the sintered body.

Example ten

The evaluation of the relationship between the amount of different dispersant added and the electrical properties of the sintered body was carried out using the dispersant of the present invention and the PMAAN dispersant. The dispersion is prepared by weighting the powder to deionized water by 3:2, and changing the amount of the dispersant added to the weight of the powder is 0.5:1000, 1:1000, 2:1000, 3:1000, 5:1000, adjusted The slurry was mixed until pH = 9, and after ball milling, the sample was dried, ground into a powder and sieved, and pressed into a disk shape by a uniaxial press molding machine. After the sample was sintered at a constant temperature of 1280 ° C for 6 hours, the surface was coated with silver glue to obtain a silver electrode, and the test piece was sandwiched with an electrode using an impedance analyzer (HP 4284, Palo Alto, California, USA), and the test frequency was 1 KHz, which was measurable. The capacitance value and the dielectric loss factor are calculated to obtain the dielectric constant value and the dielectric loss value of the sintered body.

Figure 15 is a graph showing the relationship between the amount of dispersant added and the dielectric constant of the sintered body. The embryo body to which no dispersant was added had a dielectric constant value of about 1512. When the dispersant is incorporated, the optimum dosages of the three dispersants for the highest dielectric constant of the sintered body are: PVM, 3 mg/g BT, 1972; PVMM, 2 mg/g BT, 2003; PMAAN, 3 mg /g BT, 1952. Figure 16 is a graph showing the relationship between the amount of dispersant added and the dielectric loss of the sintered body. The embryo body without added dispersant has the highest dielectric loss value of 0.047. When the dispersant is added, the three dispersants make The optimal doses for the lowest dielectric loss value of the embryo body were: PVM, 1 mg/g BT, 0.023; PVMM, 2 mg/g BT, 0.023; PMAAN, 2 mg/g BT, 0.02. It shows that adding PVM and PVMM can improve the dielectric properties of the embryo body.

According to the test results, the addition of the amphoteric copolymer of the present invention to the barium titanate slurry can simultaneously produce two dispersion modes of electrostatic repulsion and steric hindrance, thereby reducing the viscosity of the barium titanate slurry and reducing the aggregation of the powder particles. And the time of increasing the particle suspension has a good dispersion effect on the barium titanate slurry. In addition, the addition of the amphoteric copolymer of the present invention can reduce the amount of cerium ions eluted in the barium titanate slurry, and the improvement of the addition of PMAAN increases the disadvantage of the amount of cerium ions eluted in the barium titanate slurry, thereby improving the electrical properties of the sintered body. Therefore, the water-soluble amphoteric copolymer of the present invention is a ceramic powder slurry dispersing agent having superior properties.

Fig. 1 is a ¹ H-NMR spectrum of N-(4-vinylphenyl)-N,N-dimethylglycine (VBDMGly) or a salt thereof.

Figure 2 shows the IR spectrum of VBDMGly.

Figure 3 is a ¹ H-NMR spectrum of poly(N-(4-vinylphenyl)-N,N-dimethylglycine/methacrylate) (PVM).

Figure 4 shows the IR spectrum of PVM.

Figure 5 ¹ H-NMR spectrum of poly(N-(4-vinylphenyl)-N,N-dimethylglycine/methacrylamide/methacrylate) (PVMM).

Figure 6 shows the IR spectrum of PVMM.

Figure 7 is a graph showing the effect of different dispersant additions on the viscosity of barium titanate paste. The illustration of the ringing.

Figure 8 is a graph showing the effect of different dispersant additions on the average particle size ( d ₅₀ ) of barium titanate slurry particles.

Figure 9 is a graph showing the effect of the amount of PVM added on the dispersion volume of a 10% by weight barium titanate slurry.

Figure 10 is a graph showing the effect of the amount of PVMM added on the dispersion volume of a 10% by weight barium titanate slurry.

Figure 11 is a graph showing the effect of the amount of PMAAN added on the dispersion volume of a 10% by weight barium titanate slurry.

Figure 12 is a graph showing the effect of the amount of dispersant added on the viscosity of a 75 wt% alumina slurry.

Figure 13 is a graph showing the effect of the amount of dispersant added on the viscosity of a 45% by weight titanium dioxide slurry.

Fig. 14 is a graph showing the effect of the amount of dispersant added on the amount of slurry cerium ion eluted.

Fig. 15 is a graph showing the effect of the amount of dispersant added on the dielectric constant of the sintered body.

Figure 16 is a graph showing the effect of the amount of dispersant added on the dielectric loss of the sintered body.

Claims (9)

An amphoteric monomer of the following formula (1): Wherein R ₁ is H, C _x H _2x+1 , x is an integer from 1 to 5, and R ₂ is H, NH ₄ ⁺ or an alkali metal ion. A method for producing an amphoteric monomer according to claim 1, which comprises reacting sodium chloroacetate with N-(4-vinylphenyl)-N,N-dimethylamine or N-(4) -α-C1-C5-alkyl-vinylphenyl)-N,N-dimethylamine at a molar ratio of 1:1, and the reaction environment is acidic with HCl, the reaction temperature is 60-90 ° C, and the temperature is constant. The reaction is carried out for 8 to 16 hours, and the obtained product is extracted with acetone or methanol as an extraction solvent to obtain the amphoteric monomer. A water-soluble amphoteric copolymer having the structure of the following formula (2): Wherein R ₁ is H, C _x H _2x+1 , x is an integer from 1 to 5, R ₂ is H, NH ₄ ⁺ or an alkali metal ion; m is an integer from 10 to 1000, and n is an integer from 10 to 1000; R is an acrylic acid, acrylamide, methacrylic acid, methacrylamide, or a combination of any of the foregoing, and a derivative thereof, and is a starting comonomer. A method for producing an amphoteric copolymer as described in claim 3, which comprises the starting comonomer and the amphoteric monomer described in claim 1 in the polymerization of potassium persulfate or ammonium persulfate The initiator, sodium methacrylate sulfonate is used as a chain transfer agent, and is reacted at a reaction temperature of 60-90 ° C for 6-10 hours, and the obtained product is extracted with acetone or methanol as a solvent. A ceramic powder slurry comprising the amphoteric copolymer as described in claim 3, wherein the amphoteric copolymer is dissolved in water and added to the ceramic powder to form a slurry, which reduces the ceramic powder slurry. The viscosity of the body, wherein the ceramic powder slurry comprises barium titanate, aluminum oxide and titanium dioxide. The ceramic powder slurry according to claim 5, wherein the amphoteric copolymer is added in an amount of 0.05 to 1.0% by weight. The ceramic powder slurry according to claim 5, wherein the ceramic powder is barium titanate, and the ceramic powder has a lower amount of cerium ions eluted than the ceramic powder slurry to which the amphoteric copolymer is not added. . The ceramic powder slurry according to claim 5, characterized in that the viscosity is lower than that of the ceramic powder slurry to which the amphoteric copolymer is not added, and the stability is better than that of the ceramic powder slurry to which the amphoteric copolymer is not added. Body The powder particle size is smaller than the ceramic powder slurry to which the amphoteric copolymer is not added. The ceramic powder slurry containing the amphoteric copolymer according to claim 5, wherein after the slurry is ball milled, the sample is dried, ground into a powder and sieved, and then pressed into a circle. In the form of a disk, after the obtained sample is sintered at a constant temperature of 1000-1300 ° C for 4-8 hours, the dielectric constant value of the obtained sintered body is higher than that of the sintered body to which the amphoteric copolymer is not added, and the dielectric loss value is lower than that of the non-added type. A sintered body of a copolymer.