JP2002293651A - Dewaxing/sintering setter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dewaxing/sintering setter which is used when a compact of each of various electric or electronic parts is dewaxed/sintered and is not cracked particularly even when heated or cooled rapidly. SOLUTION: This dewaxing/sintering setter consists of porous ceramics having continuous pores having 70-98 volume% porosity, 100-2,000 μm pore size and 20-90% area ratio of openings and a three-dimensional mesh-like structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention degreases molded articles of various electric and electronic parts such as ceramic capacitors, chip type resistors, ring varistors, semiconductor capacitors, piezoelectric material products, chip type multilayer capacitors and chip type thermistors. The present invention relates to a setter used for firing, particularly to a setter which does not crack even if it is rapidly heated and cooled.

[0002]

2. Description of the Related Art In general, ceramic capacitors, chip type resistors, ring varistors, semiconductor capacitors,
To manufacture electrical and electronic components such as piezoelectric material products, chip-type multilayer capacitors, and chip-type thermistors, a mixture is prepared by mixing organic resin and a solvent with each raw material powder, and this mixture is molded and molded. It is known that a green body is manufactured, and the green body is mounted on a setter made of porous ceramics, and degreased and fired while passing through a degreasing furnace and a firing furnace.

[0003] The setter made of the porous ceramics is, in terms of mass% (hereinafter,% means mass%), a water-insoluble hydrocarbon organic solvent having 5 to 8 carbon atoms: 0.5 to
10%, surfactant: 0.05 to 5%, water-soluble resin binder: 0.5 to 20%, average particle diameter: 0.05 to 20 μm ceramic powder: 5 to 5%
70%, if necessary, a plasticizer comprising one or more of polyhydric alcohols, oils, fats, ethers and esters: 0.1 to 15%, water: remaining, a mixture having a composition comprising: Is molded into a predetermined setter shape by a known doctor blade method, slip casting method, or the like, and when the molded body is kept at a temperature of 5 ° C. or more, the water-insoluble hydrocarbon-based organic solvent has a vapor larger than water. Since it has a pressure, it is vaporized, becomes a gas and evaporates from the molded body, so that a porous molded body in which a large number of fine and sized bubbles are generated is formed in the molded body, and this porous body is formed. It is manufactured by sintering a green compact. The setter thus obtained has a porosity of 25.
It is composed of porous ceramics having continuous pores having a pore size of less than 100 μm and a skeleton having a three-dimensional network structure.

[0004]

In recent years, electric and electronic parts such as ceramic capacitors, chip-type resistors, ring varistors, semiconductor capacitors, piezoelectric material products, chip-type multilayer capacitors, and chip-type thermistors have been reduced in usage. On the other hand, on the other hand, the demand for reduction of the unit price is intense, and therefore, further reduction of the manufacturing cost is required. Means for reducing the degreasing / firing time of the molded article to increase the number of products manufactured per unit time have been considered as a means of reducing the cost of these electric and electronic components. -After being charged into the firing furnace, it must be rapidly heated in a degreasing / sintering furnace, kept at a predetermined temperature for a predetermined time, and then rapidly cooled. Setters tend to crack when heated and cooled rapidly in a degreasing and sintering furnace. Especially in the case of a conventional ceramic setter, cracks occur during rapid cooling and the cooling rate is 50 ° C / m.
At the point of “in”, the cooling rate cannot be increased any more because cracks occur in the setter, so that the firing time cannot be shortened at present.

[0005]

Means for Solving the Problems Accordingly, the present inventors have
Research was conducted to produce a setter that does not crack even after rapid heating and rapid cooling. As a result, the porosity of the degreasing / sintering setter is increased from the conventional 70% by volume,
The cooling rate of a setter made of porous ceramics in which the average opening diameter of the holes formed on the surface is 100 to 2000 μm larger than the conventional average opening diameter and the opening area ratio is 20 to 90% is 100%. No cracking occurs even if the cooling is rapidly performed at a rate of ° C./min.
That's the research result.

The present invention has been made based on the results of the above research, and has a porosity of more than 70 to 98% by volume, a pore diameter of 100 to 2000 μm, and an opening area ratio of 20 to 2000 μm.
The present invention is characterized in that the setter for degreasing / firing comprises porous ceramics having continuous pores having 90% and a three-dimensional network structure.

[0007] The porous ceramics constituting the degreasing / firing setter of the present invention include Al ₂ O ₃ , ZrO ₂ , and Si.
It is made of O ₂ , cordierite, SiC, Si ₃ N ₄ , AlN, mullite, sialin, or the like, and may be a composite of these ceramics.

In order to produce the degreasing / sintering setter floor plate of the present invention, ceramic powder having an average particle size of 0.05 to 3 μm is used as a raw material powder, and an organic solvent, a surfactant, Water-soluble resin binder,
A mixed slurry is prepared by blending a plasticizer and pure water so as to have the following composition and kneading for 1 to 16 hours. Water-insoluble hydrocarbon organic solvent having 5 to 8 carbon atoms: 0.5 to
10%, surfactant: 0.05 to 5%, water-soluble resin binder: 0.5 to 20%, average particle diameter: 0.05 to 3 μm ceramic powder: 30
-80%, if necessary, a plasticizer composed of one or more of polyhydric alcohols, oils, fats, ethers, and esters: 0.1 to 15%, water: remaining (% is mass% Is shown). From this mixed slurry, a plate-like green molded body is formed by a known method such as a doctor blade method or a slip casting method, and the plate-like green molded body is humidified at room temperature at a humidity of 5 to 6%.
After the first foaming treatment at 5%, the temperature and temperature are kept at 30 to 60 ° C and the humidity is 65% or more (preferably 8%).
0% or more), a plate-like porous molded body having a porosity larger than usual: more than 70 to 98% and a pore size larger than normal: 100 to 2000 μm is obtained, The plate-shaped porous molded body is fired to produce a setter made of the porous ceramic of the present invention.

The water-insoluble hydrocarbon-based organic solvent having 5 to 8 carbon atoms used for preparing the mixed slurry includes:
Neopentane, hexane, isohexane, heptane, isoheptane, benzene, octane, toluene and the like can be used. As the surfactant, the above-mentioned commercially available neutral synthetic detergent for kitchen can be used, but it is more preferable to use sodium dodecylbenzenesulfonate. As the water-soluble resin binder, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, carboxymethyl cellulose ammonium, ethyl cellulose, and polyvinyl alcohol can be used. As the plasticizer, polyethylene glycol, olive oil, petroleum ether, di-N-butyl phthalate, and glycerin can be used.

[0010]

Next, the degreasing / firing setter made of the porous ceramic of the present invention will be specifically described with reference to examples. First, alumina powder having an average particle diameter shown in Table 1 was prepared as a raw material powder. In addition, carbon number 5
N-hexane as a water-insoluble hydrocarbon organic solvent of 8,
Sodium dodecylbenzenesulfonate (hereinafter, referred to as DBS) was prepared as a surfactant, hydroxypropylmethylcellulose (hereinafter, referred to as HPMC) as a water-soluble resin binder, and glycerin as a plasticizer. Further, distilled water was prepared as water.

The mixed ceramic powder, n-hexane, DBS, HPMC, glycerin and distilled water were blended in the proportions shown in Table 1 and charged into a kneader to knead for 10 hours to prepare a slurry. The slurry was formed into a molded product having a thickness of 3 mm by a doctor blade method, and the obtained molded product was subjected to a first foaming treatment of exposing the molded product to the temperature and humidity shown in Table 2 for 5 minutes. Foaming was performed by performing a second foaming treatment at the indicated temperature and humidity for 10 minutes to produce a foamed molded article. These foamed moldings are further degreased in the atmosphere at a temperature of 500 ° C. for 60 minutes, and then in the air at a temperature of 1650 ° C. and 10 ° C.
Setters 1 to 1 of the present invention consisting of porous ceramics having a thickness of 2 mm by sintering under the condition of holding time
No. 0 and conventional setters 1 and 2 were manufactured, and the porosity, pore diameter and surface opening area ratio of the setter were measured. The results are shown in Table 2.

The present setter 1 thus obtained
-10 and conventional setters 1-2 in the atmosphere,
Temperature rising rate: 50 ° C./min, then temperature: 13
The temperature was kept at 00 ° C for 2 hours, and then the temperature was lowered at a rate of 100 ° C /
The temperature was lowered to room temperature in minutes, and whether or not cracks occurred in the setter was visually observed. The results are shown in Table 2.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

From the results shown in Tables 1 and 2, it can be seen that cracks did not occur in the setters 1 to 10 of the present invention, but cracks occurred in the conventional setters 1 and 2. As described above, the setter made of the porous ceramic of the present invention can reduce the manufacturing time of electric / electronic parts because cracks do not occur during rapid heating and cooling, thereby further reducing costs. It can greatly contribute to the development of the electric and electronic industries.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takumi Shibuya 1230 Kamijiya, Okegawa-shi, Saitama Mitsubishi Materials Corporation (72) Inventor Hironori Ueno 1230 Kamijiya, Okegawa-shi, Saitama Mitsubishi Materials Corporation Okegawa Factory F-term (reference) 4K055 AA08 HA02 HA14

Claims (1)

[Claims] 1. Porosity: more than 70 to 98% by volume, pore diameter: 1
A setter for degreasing / firing, comprising porous ceramics having continuous pores having an opening area ratio of 20 to 90% and a three-dimensional network structure.