JPS60179631A - Method for evaluating viscosity of kneaded material of ceramic powder and resin - Google Patents

Abstract

PURPOSE:To evaluate accurately a viscosity prior to the kneading by suspending the ceramic powder to be used into a prescribed testing solvent by a prescribed ratio to obtain the slurry, and measuring the flowing down time thereof by using a testing funnel. CONSTITUTION:The testing funnel consists of a slurry storage part 1 capable of storing a fixed quantity of the slurry, and a narrow under hole 2 for slurry drainage. The ceramic powders of different lapses of days after the pulverization and different grain sizes are used, these various powders are suspended into the testing solvent to obtain the testing slurry, and the flowing down time thereof is measured by using said testing funnel. By such a method, the viscosity of the kneaded material can be evaluated almost accurately.

Description

[Detailed Description of the Invention] Technical Field This invention relates to a process in which ceramic powder and resin are kneaded to form a kneaded product, and when a desired molded product is obtained by injection molding, the The present invention relates to a method for estimating and evaluating the viscosity of a contaminant.

BACKGROUND OF THE INVENTION In recent years, research has been conducted on the use of non-oxide ceramics such as silicon nitride and silicon carbide as structural materials. In order to actually obtain a product in the desired shape using such ceramics, the ceramic powder is kneaded with resin.
It is often injection molded as a fluid kneaded product.

When injection molding is performed by mixing ceramic powder and resin in this way, the viscosity of the mixed material greatly affects the workability of injection molding and the mechanical properties of the molded product, so the viscosity of the mixed material must be adjusted appropriately. need to be adjusted.

Incidentally, the viscosity of the mixed material obtained by kneading ceramic powder and resin is greatly influenced by the characteristics of the ceramic powder. That is, when ceramic powder and resin are kneaded,
In the microscopic system, resin adheres to the outer surface of each ceramic powder particle, and the fluidity of the mixed material changes depending on the degree to which the resin adheres to the outer surface of each ceramic powder particle.

Specifically, when the degree of resin adhesion to the outer surface of individual ceramic powder particles is large, the fluidity of the cross-contaminant decreases, and when the degree of resin adhesion is small, the fluidity of the cross-conductor increases. Furthermore, the degree to which the resin adheres to the outer surface of the ceramic powder particles depends on the particle size of the individual ceramic powder particles and the wetting property with respect to the resin.

That is, the smaller the particle size of the individual particles, the greater the degree to which the resin adheres to the ceramic powder as a whole, and the greater the wettability of the individual particles to the resin, the greater the degree to which the resin adheres.

As described above, the viscosity of the mixture of ceramic powder and resin is influenced by the characteristics of the ceramic powder, specifically the particle size and wettability with respect to the resin.

Generally, ceramic powder is manufactured by crushing a lump of ceramic using a crusher, and the particle size of the resulting powder particles is not uniform. Further, the surface of the particles immediately after pulverization is very active and highly wettable with resin, but the activity gradually decreases as time passes after pulverization. As a result, when a desired product is obtained by injection molding a mixture of ceramic powder and resin, the particle size and wettability of the ceramic powder prepared as a raw material with respect to the resin are not uniform. Therefore, during injection molding, in order to eliminate insufficient flow of the kneaded material into the mold and maintain good quality of the resulting product, the viscosity of the prepared mixture of ceramic powder and resin must be adjusted to the required level. It is essential to constantly manage the situation.

Conventionally, the viscosity of the mixture of ceramic powder and resin has been controlled based on the results of actually mixing the ceramic powder and resin and directly measuring the viscosity. However, such conventional methods have problems in that it is not possible to evaluate and manage the viscosity of the crosstalk obtained before the crosstalk occurs, and the viscosity itself is not easy to measure.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional circumstances, and it is possible to accurately evaluate the viscosity of a mixed material of ceramic powder and resin before mixing, and to easily and easily manage the viscosity of the mixed material. The purpose of this invention is to provide a method for evaluating the viscosity of a ceramic powder/resin mixture that can be performed quickly.

The structure of the invention, that is, the method for evaluating the viscosity of a ceramic powder/resin mixture according to the present invention is that, before mixing ceramic powder and resin and manufacturing a desired product by q1 extrusion molding, the ceramic powder to be used is subjected to a predetermined test. mM in the given ratio to the solvent
The slurry is made into a slurry, the flow time of the slurry is measured using a predetermined test funnel, and the viscosity of the mixture of ceramic powder and resin is evaluated based on the flow time.

This invention will be explained in more detail below.

In this invention, before mixing ceramic powder and resin to produce a desired molded product by injection molding, the ceramic powder to be used is first dissolved in a predetermined test solvent at a predetermined ratio to form a slurry. Eggplant.

It is preferable to use a lower alcohol such as ethanol as the test solvent.

Next, in this invention, regarding the slurry obtained above,
Measure the flow time using a designated test funnel.

As the test funnel, as shown in FIG. 1, a funnel having a slurry storage part 1 capable of storing a certain amount of slurry and a narrow slurry outlet 2 at the bottom can be used. The flow time is measured for each unit of slurry, and based on the measured flow time, the viscosity of the ceramic powder and resin to be tested is evaluated.

For evaluation, it is convenient to use materials prepared in advance as follows.

Using ceramic powders that differ in the number of days since pulverization and the particle size, first dissolve each of the various powders, such as No. Measure the flow time using Next, the viscosity of each mixed material obtained by kneading the above-mentioned various powders with the resin that is kneaded together with the ceramic powder during the production of the molded product by injection molding is measured. Using the above flow time measurement results and viscosity measurement results, materials showing the relationship between the test slurry flow time and the viscosity of the kneaded product are created.

When actually manufacturing the desired molded product by injection molding by mixing ceramic powder and resin, the ceramic powder to be used must be dissolved in advance in the same ratio in the test solvent used when creating the materials to form a slurry. The flow time of the slurry was measured using the test funnel shown in FIG. 1 that was used when preparing the data. By comparing the measurement results with the above-mentioned data, it is possible to almost accurately evaluate the viscosity when the ceramic powder and resin are mixed together.

Example Examples of this invention are described below.

The bulk silicon nitride is crushed by an alumina ball mill,
The particles whose particle size was adjusted to 0-5J" 11.JJm and 2.0K were left in the atmosphere for one month. For each of these raw materials, the flow time through the funnel and the crosstalk viscosity with 1 fat were calculated. It was measured.

For the test row 1-, use the row 1- shown in Figure 1.
The test slurry for which the flow time is to be measured was made by placing 400 mm of nylon balls with an outer diameter of 15 mm in a 1β polyethylene container.
, 300g of sample powder collected from each of the above raw materials and 400+n4 ethanol were added, and the polyethylene container was rotated at a speed of 64 r, p, m for 30 minutes using a rotating device to mix the contents. .

100+' for each of the above test slurries! Each sample was allowed to flow down from the funnel and the flow time was measured. The flow time was measured six times for each test slurry, and the average was taken as the flow time for each test slurry.

To measure crosstalk viscosity with resin, each of the above-mentioned raw materials was tested at 5k each.
The viscosity of the kneaded product when E, v, A, and 1k (l of ethylene vinyl acetate copolymer) were put into a twin-screw extruder was determined by kneading and curing at a temperature of 1.30°C. Flow pressure (surface pressure) when the rotation speed of the tool is 50 r, p8m
It was measured as

The above measurement results are shown in FIG. 2 as the relationship between the particle size of the raw powder particles, the flow time of the test slurry, and the particle size of the raw powder particles and crosstalk viscosity.

Next, bulk silicon nitride was ground with an alumina ball mill, and the particle size was adjusted to IJJIIG, using raw material powder.
The funnel flow time of the test slurry and the crosstalk viscosity with the resin were measured for those immediately after pulverization and those that had been left in the atmosphere for 1, 3, and 5 days in the same manner as those described above. The measurement results are shown in FIG. 3 as the relationship between the number of days that have passed since the raw material powder was pulverized, the flow time of the test slurry, and the number of days that have passed since the raw material powder was pulverized and the crosstalk viscosity.

As shown in FIG. 2, as the average particle size of the raw material powder increases, the flow time and crosstalk viscosity decrease, and the changes in flow time and crosstalk viscosity that correspond to changes in the average particle size almost match.

In addition, as shown in Fig. 3, as the number of days elapsed after the raw powder was crushed, the flow time and crosstalk viscosity decreased; The changes are almost the same.

Furthermore, from the above measurement results, a calibration curve was created showing the relationship between the funnel flow time of the test slurry and the kneading viscosity of the resin, as shown in FIG. A test slurry was prepared for a silicon nitride powder whose hardness was unknown, the funnel flow time was measured, and the kneading viscosity with the resin was evaluated in advance. Furthermore, the crosstalk viscosity with the resin was actually confirmed for each of the evaluated mixed powders.

The results are shown in Table 1.

□] - - - From Table 1, it can be seen that the value of cross-mixing viscosity evaluated from the flow time of the test slurry using FIG. 4 agrees well with the actual kneading viscosity.

Effects of the Invention As described above, according to the present invention, ceramic powder is mixed with a predetermined ratio of R in a predetermined test solvent to form a slurry, and the flow time of the test slurry is measured to determine the relationship between the ceramic powder and the resin. Before kneading ceramic powder and resin to manufacture a desired product by injection molding, the viscosity of the mixed product obtained by kneading is almost accurately evaluated. This makes it possible to easily and quickly manage the viscosity of the mixed material to be injection molded.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a test funnel, and Fig. 2 is a cross-sectional view of a test funnel. FIG. 3 is a diagram showing the relationship between the cross-wire viscosity of silicon nitride powder and resin, and the relationship between the flow time measurement result and particle size, and the kneading viscosity measurement result and particle size. Figure 3 is a diagram showing the relationship between slurry flow time and activity (number of times elapsed after crushing), and mixing viscosity with resin and activity using silicon nitride powders with similar particle sizes and different degrees of activity. . FIG. 4 is a diagram showing the relationship between the flow time of the test slurry and the mixing viscosity with the resin when silicon nitride powder is used. Figure 1 Figure 2 Figure 3 Number of days of moxibustion (days) Figure 4. 〃 (b ″, I9 lower hours)

Claims (1)

[Claims] Before kneading ceramic powder and resin to produce a desired molded product by injection molding, the ceramic powder to be used is heated at a predetermined ratio in a predetermined test solvent to form a slurry, and then poured into a predetermined test funnel. A method for evaluating the viscosity of a ceramic powder/resin mixture, characterized in that the flow time of the slurry is measured using a method, and the viscosity of the ceramic powder/resin mixture is evaluated based on the flow time.