JP2004338413A - Apparatus for producing green sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus capable of producing easily a green sheet having a high quality. <P>SOLUTION: The apparatus comprises a slurry tank 9, a pipe 6 for introducing pressure, control valves 7a and 7b for controlling pressure of the slurry tank 9, a slurry discharge pipe 8 for discharging slurry 1 in the slurry tank 9, a slurry reservoir 11 having a doctor blade 10, a liquid level gauge 12 for measuring a liquid level in the slurry reservoir 11, a green sheet molding mechanism 13 which forms the slurry 1 extruded from a space 4 between the doctor blade 10 and a carrier sheet 5 into the green sheet 3, and a pressure control means 17 which controls a pressure in the slurry tank 9 by controlling the control bulbs 7a and 7b on the basis of the measured pressure level by a pressure gauge 16 of the slurry tank 9. The method comprises operating the control valves 7a and 7b by the pressure control means 17 on the basis of signals of the liquid level gauge 12 of the slurry reservoir 11 and the pressure gauge 16 so as to control inflow of a pressure liquid. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a manufacturing apparatus for forming a green sheet used for a multilayer substrate for electronic components, and a method for manufacturing a green sheet.

As a conventional green sheet manufacturing apparatus, Patent Document 1 discloses a method in which a certain pressure is applied to a ceramic slurry in a closed slurry supply container and a ceramic slurry is supplied from a slurry supply container to a slurry reservoir having a doctor blade existing on a moving belt. There has been disclosed a technique for supplying a constant supply amount of so as to keep the height of the ceramic slurry held in the slurry reservoir constant. Further, Patent Document 2 discloses a slurry supply in which a pressurized gas is supplied into a slurry container containing a slurry and the slurry is conveyed to a slurry dam disposed near a doctor blade. And a green sheet manufacturing apparatus configured to control the supply pressure of the pressurized gas into the slurry container via a valve controller using the signal. Further, Patent Document 3 describes a green sheet manufacturing apparatus having the following configuration. For example, as shown in FIG. 2, a slurry tank 29 having a slurry delivery pipe 28, a pressure pump 22 for pressurizing and feeding the slurry 21 supplied from the slurry delivery pipe 28, A flow rate control valve 27 for adjusting the temperature, a slurry reservoir 31 having a doctor blade 30 and storing the slurry 21 supplied from a slurry delivery pipe 28, and a liquid level meter 32 provided in the slurry reservoir 31 for measuring the liquid level position of the slurry 21 A green sheet forming mechanism 33 that is disposed below the slurry reservoir 31 and forms the slurry 21 extruded from the gap 24 between the doctor blade 30 and the carrier sheet 25 into a green sheet 23; A flow control means 34 is provided for controlling the amount of slurry supplied by adjusting the control valve 27.
JP-A-60-168604 JP-A-4-80001 JP-A-62-161510

  In order to manufacture a green sheet by the doctor blade method using the apparatus of FIG. 2, first, ceramic powder and glass powder are kneaded and dispersed together with an organic binder, a solvent, a plasticizer and an appropriate amount of a dispersant, and then uniformly dispersed. The slurry 21 is obtained. The obtained slurry 21 is supplied to the slurry reservoir 31 from the slurry tank 29 to the slurry reservoir 31 by the pressure pump 22 and the flow rate control valve 27, and the slurry 21 passes through the gap 24 between the doctor blade 30 and the moving carrier sheet 25. The green sheet 23 is formed by extruding the carrier sheet 25 to a predetermined thickness. The green sheet 23 thus formed is dried, wound up, and sent to the next step.

  In order to make the thickness of the green sheet uniform and to form the surface smoothly, the slurry liquid level in the slurry reservoir is always kept constant and the slurry is supplied in a constant amount to the gap between the doctor blade and the carrier sheet. There is a need. However, in the conventional green sheet manufacturing apparatus, there is a structure having a portion in which the slurry stays therein, such as the pressure pump 22 and the flow rate control valve 27 in the slurry supply line. In some cases, a heterogeneous slurry is generated to give non-uniformity to the slurry supplied to the slurry reservoir. Such non-uniformity of the slurry appears as a streak pattern when the green sheet is formed, and there is a problem that the thickness dimension and the surface smoothness of the green sheet are serious defects.

  Also, when cleaning the part in contact with the slurry of the green sheet manufacturing apparatus after the completion of the green sheet molding, in order to prevent the slurry from sticking and to prevent the different kinds and agglomerates from being mixed into the slurry in the next green sheet molding, Slurry tanks, slurry delivery pipes, pressure pumps, flow control valves, slurry reservoirs, etc. must be disassembled and cleaned each time, and even a small amount of remaining slurry will become aggregated foreign matter during the next green sheet production. In particular, there is a problem in that the pump, the flow control valve, and the like, which have complicated structures and cannot be completely disassembled because they appear in the green sheet, cannot be reused even if they are expensive.

  An object of the present invention is to solve the above problems and to provide a manufacturing apparatus capable of easily manufacturing a high-quality green sheet.

  In order to achieve the above object, a green sheet manufacturing apparatus of the present invention has a slurry tank for storing slurry, a pressure gauge provided in the slurry tank, a pressure introduction pipe connected to the slurry tank, A control valve provided in the slurry tank for adjusting the pressure of the slurry tank, a slurry delivery pipe connected to the slurry tank for delivering the slurry in the slurry tank, and having a doctor blade for storing the slurry supplied from the slurry delivery pipe. A slurry reservoir, a liquid level gauge provided in the slurry reservoir for measuring a liquid level position of the slurry, and a slurry disposed below the slurry reservoir and extruded from a gap between a doctor blade and a carrier sheet to form a green sheet. Green sheet forming mechanism, the measured value of the liquid level gauge and the internal pressure value of the pressure gauge Hazuki formed by and a pressure control means for controlling the pressure regulation to the slurry tank the regulating valve and said.

  According to the green sheet manufacturing apparatus of the present invention, the pressure control means for controlling the pressure in the slurry tank by adjusting the control valve based on the measured value of the liquid level gauge and the internal pressure value of the pressure gauge provided in the slurry tank , The liquid level position of the slurry in the slurry reservoir can be kept constant, and a structure in which a slurry retaining portion such as a pressure pump or a flow control valve is provided in the slurry delivery line. Is unnecessary, the slurry quality supplied to the slurry reservoir can be maintained uniformly, and when the green sheet is formed, the thickness is excellent in dimensional accuracy and the surface is smooth without any streak pattern or foreign matter. Also excellent goon sheets can be formed. Further, since there is no pressure pump or flow control valve, after the completion of green sheet molding, the portion of the green sheet manufacturing apparatus that has come into contact with the slurry can be easily washed.

  Further, according to the green sheet manufacturing apparatus of the present invention, the liquid surface position of the slurry in the slurry reservoir corresponding to the slurry having various viscosities from low viscosity and good fluidity to high viscosity and poor fluidity is provided. Can be kept constant.

  The green sheet manufacturing method of the present invention using the above-described green sheet manufacturing apparatus supplies the slurry from the slurry tank to the slurry reservoir, and extrudes the slurry in the slurry reservoir from the gap between the doctor blade and the carrier sheet to form a green sheet. A green sheet manufacturing method, wherein the slurry is fed to the slurry reservoir by feeding a pressure fluid to the slurry tank, and the slurry is supplied based on the liquid level position of the slurry reservoir and the internal pressure value of the slurry tank. It is characterized in that the inflow amount of the pressure fluid is adjusted.

  ADVANTAGE OF THE INVENTION According to this invention, since stable supply of a homogeneous slurry is attained, it becomes possible to manufacture a green sheet excellent in thickness dimensional accuracy and surface smoothness. In addition, after the production of the green sheet is completed, there is an excellent practical effect that the cost for maintaining the operation of the equipment such as the cleaning operation of the production equipment can be reduced.

  In the green sheet manufacturing apparatus according to the present invention, the pressure control means is configured to control at least the air pressure introduced from a pressure introduction pipe connected to a slurry tank in which the slurry is stored, based on a measurement value of a liquid level gauge provided in the slurry reservoir. The pressure in the slurry tank is controlled by adjusting the inflow amount of a fluid that is inert to the slurry such as air or nitrogen gas having a higher pressure, and the slurry in the slurry tank is connected to the slurry tank. By adjusting and supplying the slurry to the slurry reservoir having the doctor blade through the delivery pipe, the level of the slurry in the slurry reservoir is kept constant. By keeping the level of the slurry in the slurry reservoir constant, the amount of the slurry extruded from the gap between the doctor blade and the carrier sheet can be kept constant, and the green sheet molding mechanism disposed below the slurry reservoir can A green sheet having a stable thickness can be formed.

  Further, in the manufacturing apparatus of the present invention, the pressure control means measures a deviation amount between the liquid level position of the liquid level gauge provided in the slurry reservoir and the set liquid level position, and measures the pressure of the pressure gauge provided in the slurry tank. The flow of an inert fluid such as air or nitrogen gas having a pressure higher than at least the atmospheric pressure introduced from the pressure introducing pipe into the slurry tank in which the slurry is stored based on a control parameter preset for the value. The amount in the slurry tank is controlled by controlling the pressure in the slurry tank by adjusting the amount with a control valve, and adjusting and supplying the slurry in the slurry tank to the slurry tank having doctor blades through a slurry delivery pipe connected to the slurry tank. The liquid level of the slurry is kept constant.

  The slurry tank of the manufacturing apparatus of the present invention may be sealed as long as its internal pressure can be controlled, and it is desirable that the slurry tank has a simple shape in which slurry hardly remains and is easy to clean. Further, the control valve of the present manufacturing apparatus is a power valve that can be remotely operated by a control signal from the pressure control means, and is preferably of a type that can control the amount of valve operation by feedback control to the pressure control means. The installation position of the control valve includes not only a case where the control valve is provided directly on the slurry tank but also a case where the control valve is provided on a pressure introduction pipe connected to the slurry tank. The slurry delivery pipe that sends out the slurry in the slurry tank is preferably an easily detachable pipe, and the part that directly contacts the slurry other than the pressure-resistant reinforcing part may be made of any material that is excellent in chemical resistance, and the cost of cleaning It may be disposable in order to reduce waste. A non-contact type liquid level meter that measures the liquid level of the slurry provided in the slurry reservoir and uses the reflected light from the liquid level, or a contact type liquid level meter with a hollow float can be used. It is preferable to use a type capable of converting the information on the liquid surface position of the slurry into an electric signal or the like and transmitting it to the pressure control means.

  Further, the pressure gauge provided in the slurry tank of the manufacturing apparatus of the present invention has a type in which a detection unit is protected from an organic solvent or the like of the slurry, and can convert pressure information into an electric signal or the like and transmit it to pressure control means. Are preferred. When controlling the pressure in the slurry tank via the pressure gauge, the pressure control means calculates the viscosity of the slurry with respect to the pressure value of the pressure gauge from the deviation between the liquid level position and the set position of the slurry in the liquid level gauge. It is necessary to be able to output a command of the operation amount of the control valve by a control parameter suitable for the control valve.

  Embodiments will be described below with reference to the conceptual diagram of the green sheet manufacturing apparatus according to the present invention shown in FIG. The green sheet manufacturing apparatus according to the embodiment of the present application includes a slurry tank 9 for storing the slurry 1, a pressure introducing pipe 6 connected to the slurry tank 9, a control valve 7 a provided in the slurry tank 9 for adjusting the pressure of the slurry tank 9, 7b, a slurry delivery pipe 8 connected to the slurry tank 9 and delivering the slurry 1 in the slurry tank 9, a slurry reservoir 11 having a doctor blade 10 and storing the slurry 1 supplied from the slurry delivery pipe 8, A liquid level gauge 12 provided at 11 for measuring a liquid level position of the slurry 1, and a slurry 1 disposed below the slurry reservoir 11 and extruded from a gap 4 between the doctor blade 10 and the carrier sheet 5 to form a green sheet 3. Of the green sheet forming mechanism 13, the measured value of the liquid level gauge 12 and the pressure gauge 16 provided in the slurry tank 9. Regulating valve 7a on the basis of the section pressure value, in which modulate 7b made comprises a pressure control means 17 for controlling the pressure in the slurry tank 9. Generally, the green sheet manufacturing apparatus has a dryer 15 for drying the slurry 1 formed on the carrier sheet 5.

  The pressure control means 17 of the green sheet manufacturing apparatus of the present embodiment measures a deviation amount between the liquid level position of the liquid level gauge 12 and the set liquid level position, and obtains a pressure value of the pressure gauge 16 provided in the slurry tank 9. On the other hand, the pressure in the slurry tank 9 is controlled by controlling the inflow amount of the air 2 introduced from the pressure introducing pipe 6 into the slurry tank 9 based on control parameters set in advance by the control valves 7a and 7b and performing feedback control. Is controlled, and the slurry 1 is adjusted and supplied to the slurry reservoir 11 through the slurry delivery pipe 8, whereby the level of the slurry 1 in the slurry reservoir 11 can be kept constant.

  A case where a green sheet is manufactured using the above-described green sheet manufacturing apparatus will be described. First, a ceramic powder and a glass powder were kneaded with an organic binder, a solvent, a plasticizer, an appropriate amount of a dispersant, and the like, and dispersed to obtain a uniform slurry 1. The obtained slurry 1 is accommodated in a slurry tank 9, the slurry tank 9 is sealed, and air 2 is fed as a pressure fluid from a pressure introduction pipe 6 to feed the slurry 1 to a slurry reservoir 11 through a slurry delivery pipe 8. did. Next, when the slurry 1 pumped to the slurry reservoir 11 reaches a predetermined range of the liquid level, a signal of the liquid level position of the slurry 1 and a signal of the pressure gauge 16 provided in the slurry tank 9 are sent from the level gauge 12 to the pressure control means 17. Signals of the internal pressure value were sent, and based on these signals, the control valves 7a and 7b were operated to control the pressure in the slurry tank 9 by adjusting the amount of air 2 introduced. By controlling the pressure in the slurry tank 9 to adjust the amount of slurry supply, the level of the slurry in the slurry reservoir 11 was kept constant.

  As described above, when the green sheet 3 was formed while keeping the slurry liquid level of the slurry reservoir 11 constant, the obtained green sheet 3 had improved thickness dimensional accuracy, and had a streak-like pattern or It was excellent in smoothness with no defects such as foreign matter observed.

FIG. 1 is a conceptual diagram of a green sheet manufacturing apparatus of the present invention. The conceptual diagram of the conventional green sheet manufacturing apparatus.

Explanation of reference numerals

1 slurry 2 air (pressure fluid)
Reference Signs List 3 green sheet 4 gap 5 carrier sheet 6 pressure introduction pipes 7a, 7b control valve 8 slurry delivery pipe 9 slurry tank 10 doctor blade 11 slurry reservoir 12 level gauge 13 green sheet forming mechanism 17 pressure control means 15 dryer 16 pressure gauge

Claims (2)

  A slurry tank for storing slurry, a pressure gauge provided in the slurry tank, a pressure introducing pipe connected to the slurry tank, a control valve provided in the slurry tank for adjusting the pressure of the slurry tank, and the slurry tank A slurry delivery pipe connected to the slurry delivery pipe for delivering the slurry in the slurry tank, a slurry reservoir having a doctor blade for storing the slurry supplied from the slurry delivery pipe, and a liquid provided in the slurry reservoir for measuring a liquid level position of the slurry. A level meter, a green sheet forming mechanism disposed below the slurry reservoir and forming a slurry extruded from a gap between the doctor blade and the carrier sheet into a green sheet, and a measurement value of the liquid level meter and an inside of the pressure gauge. Pressure control for controlling the pressure in the slurry tank by adjusting the control valve based on a pressure value Green sheet manufacturing apparatus characterized by comprising; and a stage. A green sheet manufacturing method comprising: supplying a slurry from a slurry tank to a slurry reservoir; extruding a slurry in the slurry reservoir from a gap between a doctor blade and a carrier sheet to form a green sheet;
Feeding the pressure fluid into the slurry tank to feed the slurry into the slurry reservoir, and adjusting the inflow amount of the pressure fluid based on the liquid surface position of the slurry reservoir and the internal pressure value of the slurry tank. A method for manufacturing a green sheet.