JPH07102198A - Preparation of dielectric coating - Google Patents

Abstract

PURPOSE:To provide a method for preparing a dielectric coating which can attain good dispersion in a shortened time with high productivity. CONSTITUTION:In the preparation of dielectric coating where the powder of dielectric substance, solvent, binder and other additives are dispersed in a ball mill to give the coating, the powder of dielectric substance is preliminarily dispersed in a needed amount of the solvent to loosen the secondary aggregation of the powder, then the rest of the solvent, the binder and other additives are added simultaneously, kneaded with the ball mill to give the objective coating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a dielectric coating material used for producing a ceramic electronic component such as a laminated ceramic chip capacitor.

[0002]

2. Description of the Related Art Conventionally, a dielectric coating material for manufacturing a monolithic ceramic chip capacitor has a dielectric powder in a predetermined amount.
A solvent, a binder, and other additives were simultaneously mixed at the initial stage of coating preparation (simultaneous mixing / dispersion method), and kneaded by a ball mill until the coatability as a coating and the dispersed state were improved.

[0003]

However, in the case of the conventional simultaneous mixing and dispersion method, in order to loosen the agglomerates of the dielectric powder and bring them into a state close to primary particles, good coatability and good dispersion state are obtained. It was necessary to knead the amount of balls with respect to all paint components in a volume ratio of about 0.6 to 2 or knead for a considerably long time.

However, when the amount of balls is increased, the yield of the coating material is lowered, and the amount charged at one time is also reduced, so that the production efficiency is lowered. Further, there is a problem that the production efficiency is low because kneading is required for a long time.

In view of the above conventional problems, it is an object of the present invention to provide a method for producing a dielectric coating material which can achieve a good dispersion state in a short time and is excellent in productivity.

[0006]

The present invention provides a dielectric powder,
In a method for producing a dielectric coating material prepared by dispersing a solvent, a binder, and other additives in a ball mill, the dielectric powder is previously dispersed in a required amount of solvent and a ball mill to loosen secondary aggregation of the powder to some extent. After that, the remaining solvent, binder and other additives are simultaneously added and kneaded in a ball mill to form a paint.

Preferably, the binder is previously dissolved in a solvent and additives to be added later, and when the dielectric powder is dispersed in the solvent, the volume ratio of balls / (dielectric powder + solvent) is 1/3 to. 3/2, (ball + dielectric powder + solvent) /
The volume ratio of the mill is 3/10 to 7/10.

[0008]

According to the present invention, the dielectric powder is dispersed in a solvent in advance to loosen the agglomeration of the powder, and then the remaining components such as a binder are added and kneaded to obtain a coating material. Since the dielectric powder is dispersed in advance, it is possible to sufficiently loosen the agglomeration even in a low shear with a small amount of balls, and since the viscosity is low, the collision speed of the balls is improved and it becomes possible to form primary particles of the powder in a short time. , After that, it is only necessary to add the remaining components such as a binder and mix them uniformly. As in the conventional simultaneous mixing and dispersing method, since the binder encloses the aggregates of the dielectric powder, the amount of balls to make the aggregates into primary particles. It is not necessary to disperse the powder in a relatively high share for a long time, and the time spent improving the dispersion state can be saved. Paint manufacturing time can be considerably shortened, without the excess balls amount can produce a high yield in a short time the dielectric coating.

[0009]

EXAMPLES The method for producing the dielectric coating material of the examples of the present invention will be described in detail below.

(Example 1) A predetermined amount of a dielectric powder containing barium titanate as a main component and balls were placed in a mill having a constant volume, and the volume ratio of balls / (dielectric powder + solvent) was 1 /.
The solvent was added so that it became 4 to 2. An alcohol solvent was used as the solvent. Then, this was subjected to solvent dispersion of only the dielectric powder and the solvent under constant rotation speed. A small amount of this solvent-dispersed sample is withdrawn at regular intervals, the dispersed state (mainly the amount of aggregates) is confirmed with a particle gauge, and when it appears that the aggregates have almost disappeared, it is used as a binder based on the prescribed blending amount. Butyral resin, the remaining solvent, and other additives were added at the same time, and further ball mill kneading was performed.

As a comparative example, ball mill kneading was also performed in a system in which all components were first blended as in the conventional method.

The results are shown in Table 1 below.

[0013]

[Table 1]

As can be seen from Table 1, when the volume ratio of balls / (dielectric powder + solvent) is 1/3 to 3/2, the final coating composition is prepared, as compared with the conventional binder simultaneous mixing and kneading. The total dispersion time required up to now has been greatly shortened.

(Embodiment 2) Ball / (dielectric powder + solvent) is used by using a dielectric powder containing barium titanate as a main component.
And the volume ratio of (dielectric powder + solvent + ball) / mill in the dispersion mill is 2/10 to 8 /.
After changing to 10, the preceding dispersion of only the dielectric powder and the solvent was performed. Then, the dispersion evaluation was performed in the same manner as in Example 1, and when it was considered that the aggregates had almost disappeared, the binder, the remaining solvent, and other additives were added, and ball mill kneading was performed.

As a comparative example, ball mill kneading was also performed in a system in which all components were first blended as in the conventional method.

The results are shown in Table 2 below.

[0018]

[Table 2]

As can be seen from Table 2, when the volume ratio of (dielectric powder + solvent + ball) / mil is 3/10 to 7/10, the total dispersion time required to prepare the final good dispersion coating is short, The dispersion efficiency could be improved.

(Embodiment 3) As in Embodiment 1, first, solvent dispersion of the dielectric powder and solvent only is carried out under the condition that the volume ratio of ball / (dielectric powder + solvent) is in the range of 1/4 to 2. Done in
When it seemed that almost all the aggregates had disappeared, the components to be added later were added based on the prescribed blending amount. At that time, a binder in which the binder was previously dissolved together with the remaining solvent and other additives was added. After that, knead the ball mill,
The final paint was made.

The results are shown in Table 3 below.

[0022]

[Table 3]

As can be seen by comparing Table 1 and Table 3, according to such a method, the binder is homogeneous in the dispersion system after the solvent dispersion, as compared with the case where the binder, the remaining solvent and the like are simultaneously added and kneaded during the post-addition. The mixing speed is high, and the total time until the final coating is manufactured can be further shortened by about 5 hours.

[0024]

As described above, according to the method for producing a dielectric coating material of the present invention, the relatively large secondary agglomeration is rapidly reduced by preliminarily dispersing the dielectric powder only with the solvent at the initial stage of dispersion. The coating composition having good coatability and dispersibility can be produced in a short time only by uniformly mixing the remaining components such as the binder.

Claims (4)

[Claims] 1. A method for producing a dielectric coating material, which is produced by dispersing a dielectric powder, a solvent, a binder, and other additives in a ball mill, wherein the dielectric powder is previously dispersed in a required amount of a solvent and balls to obtain a powder. A method for producing a dielectric coating material, comprising the steps of loosening secondary agglomeration of the body to some extent, and then simultaneously adding the remaining solvent, binder and other additives and kneading with a ball mill to form a coating material. 2. The method for producing a dielectric coating material according to claim 1, wherein the binder is previously dissolved in a solvent and an additive to be added later. 3. The dielectric coating composition according to claim 1, wherein a volume ratio of balls / (dielectric powder + solvent) is 1/3 to 3/2 when the dielectric powder is dispersed in a solvent. Of manufacturing. 4. When the dielectric powder is dispersed in a solvent, the volume ratio of (ball + dielectric powder + solvent) / mil is 3/10 to 10.
The method for producing a dielectric coating material according to claim 1, wherein the method is 7/10.