JPS6033251A - Ceramic sheet manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a method of manufacturing ceramic sheets for use in consumer or industrial electronic equipment.

2. Description of the Related Art Structures of Conventional Examples and Their Problems In recent years, electronics has made rapid progress, and a large number of various substrates and products using ceramic sheets are being manufactured. For example, alumina substrates, piezoelectric buzzers, ceramic microphones, and multilayer ceramic capacitors are the most important examples.

Until now, ceramic green sheets have generally been produced by dissolving binders such as butyral resin and vinyl resin in organic solvents such as methyl ethyl ketone, butyl acetate, and alcohol, and mixing this with fine ceramic powder for a long period of time to form a slurry. A method is adopted in which the air in the slurry is defoamed, the slurry is drawn into a sheet onto a carrier film using a blade of a certain thickness, and then heated and dried to form a green sheet. However, since all the solvents are organic solvents, (1) they pose serious health hazards to the human body;

(2) Green sheet manufacturing costs and equipment cleaning costs will increase.

(3) There is a high risk of explosion accidents caused by organic solvents.

There were problems such as. In order to solve these problems, production methods using water-soluble binders such as polyvinyl alcohol and polyvinyl acetate have been proposed.

Although this new method can solve the above problems, the fine ceramic powder tends to form agglomerated structures in the water-soluble slurry at the stage of creating green sheets, and the viscosity of the slurry deviates from Newtonian flow, resulting in poor fluidity of the slurry. and poor dispersibility of ceramic fine powder. Further, the green sheet has many cranks and pinholes, making it impossible to obtain a green sheet with high density and a smooth surface. Furthermore, there were other problems such as the slow drying speed and the inability to form continuous sheets, which necessitated production using the Banoji method.

Purpose of the Invention The present invention has been made in view of these points, and provides a novel ceramic sheet that uses a water-soluble binder, is free from cracks and pinholes, has high smoothness, and is highly productive. The purpose of this paper is to propose a manufacturing method for .

Structure of the Invention The present invention is characterized in that an acrylic acid polymer is mixed with ceramic fine powder as a binder, and water and alcohol are added and kneaded to obtain a slurry.

DESCRIPTION OF EMBODIMENTS The present invention will be described with reference to embodiments. First, alumina powder with an average particle size of 2 μm and a purity of 96% was used as a ceramic fine powder, 16 parts of water-soluble acrylic acid polymer (resin content 30%) was added to 100 parts of this alumina powder, and 1.5 parts of glycerin was used as a plasticizer. (Polyoxy7ethylenenonylphenol ether (HLB value 17.5) as a 1° dispersant
0.52 parts of deionized water was added thereto, and 10 parts of deionized water and 20 parts of methyl alcohol were blended therein. These are placed in a polyethylene pot, the same amount of alumina balls as the ceramic powder are added, and the mixture is kneaded for about 20 hours to obtain slurry 1). After that, the slurry excluding the alumina balls was mixed with
2 Place the slurry on a low-speed pot stand of Or, p, m, and while rotating, defoaming the air in the slurry to make a homogeneous slurry. After that, adjust the viscosity of the slurry with water and alcohol,
A green sheet is produced by drawing the sheet with a feeder having a predetermined gap.

As a result of firing the Anovena green sheet thus obtained and the sheet obtained by the conventional method at 1800°C, alumina having the properties shown in the table below was obtained.

Here, Green Note, which was made into a sheet by slurrying polyvinyl alcohol resin with an organic solvent (n-butyl acetate) using polyvinyl alcohol resin as an inder and water as a solvent, was used as Example 1 of the conventional method. Example 2 also shows a green sheet prepared by slurrying the green sheet using the same method.

As is clear from the above table, the method of the present invention was superior to the conventional method in terms of quality, and the productivity was similar to that in the case of using an organic solvent.

In the above example, 4.5 parts of acrylic acid polymer was added to the binder as a resin. However, if this resin content is less than 1.5 parts, the green sheet will not have solidity and cracks will occur. will be included. Moreover, if it exceeds 20 parts, cracks will appear during sintering of the green sheet, and physical properties (surface roughness, apparent specific gravity) will deteriorate. In addition, if the total amount of water and alcohol is less than 20 parts per 100 parts of fine ceramic powder, slug IJ-
Moreover, if it exceeds 50 parts, the slurry will have a low viscosity and the shibinder and ceramic fine powder will separate, which is not good. Furthermore, if the ratio of water to alcohol is less than -0.5 water/alcohol -1, the effect on the human body will be large and the production cost will be high. On the other hand, if the ratio exceeds 1,5 water/1 alcohol, the solidification and drying properties of the slurry will deteriorate, resulting in poor productivity. Next, if the degree of polymerization of the water-solvent acrylic acid polymer is less than 100, cracks will easily occur in the sheet, and if it exceeds 2000, it will not be possible to obtain a smooth green sheet even if the viscosity of the slurry is lowered. .

Effects of the Invention As described above, the present invention provides extremely excellent Sesimink substrates and products, and since the organic solvent is partially replaced with water, there is little impact on the human body.
Even if it adheres to equipment, walls, or floors, it can be easily washed off with water, making it extremely preferable to handle environmentally sanitation soil as such. Furthermore, since productivity is excellent and alcohol and water can be obtained at low cost, manufacturing costs are also very advantageous compared to conventional methods. Moreover, excellent results can be obtained in terms of quality.

In the above points, the present invention is industrially significant and has great value.

Claims (3)

[Claims] (1) Using a soluble acrylic acid polymer as a binder, the resin content is 1.5 to 20 parts per 100 parts of fine ceramic powder.
A ceramic sheet is produced by adding an appropriate amount of a dispersant, adding water and alcohol, and kneading the resulting slurry for a required period of time to form a sheet, which is then solidified and dried to form a green sheet. Production method. (2) The ratio of water and alcohol to 100 parts of fine ceramic powder is 20 to 60 parts, and the ratio of water to alcohol is in the range of water = 0.5 to 1.6/alcohol - 1. A method for manufacturing a ceramic sheet according to claim (1). (3) The method for producing a ceramic sheet according to claim (1), wherein a water-soluble acrylic polymer having a degree of polymerization of 100 to 2,000 is used as the binder.