JPS6177740A - Evaluating method of kneading property of ceramic powder and resin - Google Patents

Abstract

PURPOSE:To evaluate kneading property, by measuring specified amounts of resin and ceramic powder to be used before injection molding, inputting the resin and the ceramic powder in a rotary viscosimeter, which is kept at a specified temperature, kneading them at a specified number of rotations, and measuring the duration of the maximum fluctuation width of the rotary torque. CONSTITUTION:Ceramic powder and a resin are kneaded, and a required molded product is manufactured by injection molding. Before manufacture, specified amounts of the resin and the ceramic powder to be used are measured and put into a rotary viscosimeter, which is kept at a specified temperature. They are kneaded at a specified number of rotations. After the start of kneading, the time period, during which the fluctuation width of the rotary torque value keeps the maximum value, is measured. Based on the measured time period, the kneading property of the ceramic powder and the resin used for the injection molding is evaluated. The kneading property of the ceramic powder and the resin is accurately evaluated before the kneading. Thus the fluidic molding pressure of the kneaded material can be accurately controlled.

Description

[Detailed Description of the Invention] Industrial Field of Application This invention relates to a method for kneading ceramic powder and resin to form a kneaded product, and when obtaining a desired molded product by injection molding, the invention is applied before kneading the ceramic powder and resin. The present invention relates to a method for estimating and evaluating its kneading properties.

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 kneading ceramic powder and resin and injection molding in this way, the viscosity of the kneaded material, in other words, the molding flow pressure, greatly affects the workability of injection molding and the [characteristics] of the molded product. It is necessary to appropriately adjust the molding fluid pressure of the kneaded product.

By the way, the properties of the ceramic powder greatly influence the molding flow pressure of the kneaded product obtained by kneading the ceramic powder and the resin. In other words, when ceramic powder and resin are kneaded, the resin adheres to the outer surface of each ceramic powder particle, and the quality of the kneaded product depends on the degree to which the resin adheres to the outer surface of each ceramic powder particle. liquidity changes. Specifically, when the degree of resin adhesion to the outer surface of each ceramic powder particle is large, the fluidity of the kneaded product becomes low, and when the degree of adhesion is small, the fluidity of the kneaded product becomes high. Furthermore, the degree to which resin adheres to the outer surface of the ceramic powder particles depends on the particle size and resin wettability of the individual ceramic powder particles. That is, the smaller the particle size of each individual particle, the greater the degree to which the resin adheres to the ceramic powder as a whole, and the greater the wettability of each individual particle to the resin, the greater the degree to which the resin adheres.

As described above, the molding flow pressure of a kneaded product of ceramic powder and resin is influenced by the characteristics of the ceramic powder, specifically, the particle size and compatibility with 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. Furthermore, 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 kneaded 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 obtained product, it is necessary to control the molding flow pressure of the prepared kneaded material of ceramic powder and resin to the required level. It is essential to constantly manage the situation to ensure that it is maintained.

Problems to be Solved by the Invention Conventionally, the above-mentioned control of the kneading properties of ceramic powder and Gozo was carried out based on the results of actually kneading ceramic powder and resin and directly measuring the molding flow pressure. . However, with such conventional methods, it has not been possible to evaluate and control the molding fluid pressure of the kneaded product obtained before the ceramic powder is kneaded.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional circumstances, and it is an object of the present invention to accurately evaluate the kneading properties of ceramic powder and titz before kneading, and to accurately control the molding flow compression of the kneaded product. The purpose of the present invention is to provide a method for evaluating the kneading properties of ceramic powder and resin.

A means for solving the problem, that is, the ceramic powder/resin kneading property evaluation method of the present invention, is to mix the ceramic powder and the resin to produce a desired molded product by injection molding. Each of them is placed in a specified position, put into a rotational viscometer kept at a specified temperature, and kneaded at a specified rotational speed.
The method is characterized by measuring the time during which the range of rotational torque fluctuation remains at its maximum value after the start of IIR, and evaluating the kneading properties of ceramic powder and resin used in injection molding based on the time.

DETAILED DESCRIPTION OF THE INVENTION The method for evaluating the kneading properties of ceramic powder and resin according to the present invention will be explained in detail below.

In this invention, prior to kneading ceramic powder and resin and manufacturing a desired molded product by injection molding, the resin and the ceramic powder to be used are weighed at a predetermined time, and the rotational viscosity is maintained at a predetermined temperature. Put it into a meter and knead at the specified rotation speed.

Here, the reason why the measured amounts of ceramic powder and resin are set as predetermined amounts, and the temperature and rotational speed of the rotational viscometer are set as "predetermined" is as follows.

As described above, in this invention, after the start of kneading of ceramic powder using a rotational viscometer, the time during which the range of variation in the rotational torque value remains at its maximum value (hereinafter referred to as maximum variation range duration) is measured, and the duration of the maximum variation range is measured. The kneading properties of the ceramic powder and resin used are evaluated depending on the time. For this evaluation, as described later, for example, the correlation between the maximum fluctuation width duration of ceramic powders of various particle sizes and the molding fluid pressure of the kneaded product is investigated and data prepared, and the data is used to create the data. Evaluate. Therefore, when implementing the present invention and evaluating the kneadability of ceramic powder used in injection molding, it is necessary to measure the duration of the maximum fluctuation range under the same conditions as when preparing the powder. That is, the amounts of ceramic powder and resin to be introduced into the rotational viscometer, the temperature and rotational speed of the rotational viscometer need to be the same as the values predetermined at the time of preparing the data. However, it is sufficient that these numerical values are the same as those at the time of creating the data, and various settings can be made at the time of creating the data depending on the implementation situation, for example, the type of rotational viscometer used. Therefore, in this invention, the amounts of ceramic powder and resin to be introduced into the rotational viscometer, the temperature and rotation speed of the rotational viscometer are not specifically specified, but are meant to be the same as those used when preparing the materials in advance. ,
The amounts of the ceramic powder and resin are set at predetermined quantities, the temperature of the rotational viscometer is set at a predetermined temperature, and the rotational speed thereof is set at a predetermined number of rotations.

Next, in the present invention, the maximum fluctuation range duration is measured during the kneading process as described above. The maximum fluctuation range duration can be measured by creating a torque chart that records changes in torque values over time, as shown in FIG.

When paying attention to the waveform of the torque chart shown in FIG. 1, there is a region A in which the torque fluctuation width is relatively large from the beginning of kneading. This is because at the beginning of kneading, solids, liquids, and air are mixed in the kneaded material, and the air phase has little resistance to the rotation of the rotary viscometer blade, while the liquid phase and in-phase have high resistance. This is because the change in resistance to blade rotation is large. Region A where the torque fluctuation width is large in this way is commonly referred to as a funicular. Next, the torque fluctuation width shifts from the funicular to a region B where the torque fluctuation width is relatively small. This is because the solid material (ceramic powder) in the kneaded material is coated with the liquid 1 (wood), which reduces the resistance to the rotation of the blade, and at the same time, air scatters and disappears from the kneaded material to the outside, causing the blade to rotate. This is because the change in resistance against . Region B where the torque fluctuation width is small in this way is commonly called a capillary.

Now, among the above-mentioned regions, as shown by C in the figure, there is a time period in which the range of fluctuation of the rotational torque remains at the same level. It is commonly found in various ceramic powders.

Therefore, by taking the time period C, it can be set as the maximum fluctuation range duration according to the present invention.

Next, in this invention, the ceramic η used for injection molding is determined by the maximum fluctuation width duration obtained as described above.
End and t! 1. Evaluate kneading properties with 1 fat.

For example, the evaluation can be done as follows.

For ceramic powders with different maximum variation durations,
The mixture is actually kneaded for a certain period of time depending on the kneading process, and the molding fluid pressure of the resulting kneaded product is measured, and a correlation diagram between the maximum fluctuation width duration and the molding fluid pressure is created and used as test fi51. During actual operation, the molding flow pressure of the kneaded product that is kneaded for a certain period of time at a predetermined kneading depth is estimated and evaluated using the above-mentioned kneader from the maximum fluctuation width duration of the ceramic 7-minute powder used.

Example Examples of this invention are shown below.

Sample 1): Massive silicon nitride was milled using an alumina ball mill, the particle size was adjusted to D50-1.0, and the powder was placed in 18 pieces. Contents of sample 1
Maximum fluctuation duration was measured with a Lab Blast Mill at oo+++l. Further, the above powder was left for one month (Sample 2). The maximum amplitude duration was measured for Sample 2 in the same lab blast mill used for Sample 1.

Furthermore, 10% of fine powder (Dso = 0.5 units) was added to the powder, and dry mixing was performed using a ■ type mixing method (Sample 3). Regarding Sample 3, the maximum fluctuation range duration was measured in the same manner as the other samples.

In the above, sample 1 has high surface activity and high wettability with resin, whereas sample 2 has low surface activity and low wettability with resin. Further, sample 3 has a different particle size from the other samples. Furthermore, Samples 4 to 6 were prepared with various surface activities and particle sizes, and the maximum width of 2<b was measured for each sample.

To measure the maximum fluctuation range duration for the various samples mentioned above, the Labo Blast Mill was held at 190°C, the rotating blade was rotated at 15 r, p, m, and 42 g of the wax system was first added, and then the ceramic After 168 g of powder was gradually added and the entire amount of ceramic powder was added, kneading was started when the measured temperature reached its peak.

Furthermore, each of the above samples was kneaded for 100 minutes in a large kneader, and the molding flow pressure of the resulting kneaded product was measured. The relationship between the molding fluid pressure and the maximum fluctuation width duration is shown in Figure 2. As shown in the figure, there is an extremely good correlation between the molding flow pressure and the maximum fluctuation width duration.

From FIG. 2, it can be seen that, for example, when the optimum molding flow pressure for injection molding of a kneaded material is 200 to 300 kll/c/, it is sufficient to use a ceramic powder with a maximum fluctuation range duration of 10 to 30 minutes.

Therefore, during actual operation, the maximum fluctuation range duration of the ceramic powder to be used can be checked, and whether or not it can be used can be judged based on whether the maximum fluctuation range duration is between 10 and 30 minutes.

Effects of the Invention As described above, in the ceramic powder/resin kneading property evaluation method of the present invention, the maximum fluctuation width duration when ceramic powder and resin are kneaded using a rotational viscometer is measured, and the maximum fluctuation width duration is calculated. Therefore, the kneading properties of ceramic powder and resin used for injection molding were evaluated in advance (2). As a result, it is possible to accurately determine the end of the ceramic raw material, the amount of resin, and the kneading conditions, and an optimal kneaded product can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing changes in torque value over time when ceramic powder and resin are kneaded using a rotational viscometer;
Fig. 2 is an explanatory diagram of one embodiment of the present invention, and is a diagram showing a test piece showing the relationship between the maximum strain duration and molding flow pressure for various ceramic powders. . Appearance: Toyota Motor Corporation! IJ Car Co., Ltd. Agent Patent Attorney Yutaka E8 Hisashi Take (Poka 1 person)

Claims (1)

[Claims] Before kneading ceramic powder and resin to produce a desired molded product by injection molding, the resin and the ceramic powder to be used are each weighed in predetermined amounts and placed into a rotational viscometer kept at a predetermined temperature. The method is characterized by kneading at a predetermined rotational speed, measuring the time during which the fluctuation range of the rotational torque value remains at its maximum value after the start of kneading, and evaluating the kneading properties of ceramic powder and resin used for injection molding based on that time. Ceramic powder/resin kneading performance evaluation method.