JP2965393B2 - Aqueous ceramic binder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous ceramic binder, and more particularly to a water-soluble ceramic binder from which a green sheet obtained has excellent heat-sealing properties.

[0002]

2. Description of the Related Art A ceramic circuit board is usually prepared by adding a ceramic powder such as alumina, zirconia, aluminum silicate, titanium oxide, etc. to a solution containing a binder resin and a plasticizer, mixing, defoaming, and removing the slurry. Prepared, coated on a suitable support such as a polyester film, and dried by heating.Then, the support was peeled off to obtain a green sheet, which was then punched into an appropriate shape. It is manufactured by printing circuits, characters, etc., laminating and pressing, firing, and decomposing the binder.

Conventionally, as the binder resin in the above-mentioned ceramic binder, a cellulose resin such as ethyl cellulose and a butyral resin such as a polyvinyl butyral resin have been used. Therefore, as a solvent, an organic solvent which dissolves these is used. ing. However, in recent years,
From the viewpoints of environmental pollution and toxicity, ceramic binders using water as a solvent have been required.

[0004] As such an aqueous ceramic binder, there is known an aqueous ceramic binder prepared by using polyvinyl alcohol as a binder resin and blending ethylene glycol as a plasticizer in order to enhance the handleability and post-processability of the obtained green sheet. ing. However, as the degree of integration of the ceramic circuit board increases, the green sheets are formed into a predetermined shape, a predetermined circuit is printed on each of the green sheets, and several to several tens of sheets are stacked, and are thermally fused and integrated. There is a demand for firing this to obtain a hybrid circuit board.

[0005] The above-mentioned conventional aqueous ceramic binder is generally used without any problem in the production of a ceramic circuit board for general use which does not require the heat-sealing property of the green sheet. Therefore, the green sheet is inferior in heat-sealing property and is not suitable for use.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems in the conventional aqueous ceramic binder, and is intended to provide an excellent heat-sealing property to the obtained green sheet. The purpose is to provide.

[0007]

The aqueous ceramic binder according to the present invention is characterized by containing a water-soluble polyvinyl acetal resin and a glycol having a boiling point of 230 ° C. or higher as main components. The water-soluble polyvinyl acetal resin used as a binder resin in the present invention can be obtained by reacting polyvinyl alcohol with an appropriate amount of an aldehyde in the presence of an acid catalyst. The polyvinyl alcohol used preferably has a degree of polymerization of 300 to 2000 and a degree of saponification of 75 to 99.8 mol%. Further, as to the degree of acetalization, for example, the degree of butyralization is 5 to 15 mol%, Acetalization degree is 10-5
About 0 mol% is preferable. Also, a resin acetalized with two or more aldehydes can be used as a binder resin in the present invention as long as it has water solubility.

In the present invention, the plasticizer has a boiling point of 23.
Glycols at 0 ° C. or higher are used. Examples of such glycols include diethylene glycol (boiling point 245 ° C.), triethylene glycol (boiling point 278).
° C), glycerin (boiling point 290 ° C), hexamethylene glycol (boiling point 250 ° C) and the like. Of these, glycerin, which has an excellent plasticizing effect, is particularly preferably used. The ceramic binder according to the present invention is usually used with respect to 100 parts by weight of the ceramic powder.
The polyvinyl acetal resin is used in a range of 5 to 15 parts by weight, and the plasticizer is in a range of 10 to 60 parts by weight, preferably 20 to 40 parts by weight based on 100 parts by weight of the polyvinyl acetal resin. Used for
The water serving as the solvent is not particularly limited, and the obtained slurry may have an appropriate kneading property. Used.

The ceramic binder according to the present invention is used, for example, in the manufacture of a ceramic circuit board in the same manner as in the prior art. That is, the ceramic powder is added to an aqueous solution containing a binder resin and a plasticizer, mixed and defoamed to prepare a slurry, applied on a support, dried by heating, and then peeled off the support. Get a green sheet, then
This is punched into an appropriate shape, and if necessary, a circuit, characters and the like are printed, and if necessary, a plurality of sheets are stacked, thermally fused and integrated, and then fired to obtain a hybrid circuit board. .

In the production of a ceramic product using the ceramic binder according to the present invention, it is desirable to suppress evaporation of the plasticizer during vacuum defoaming of the slurry or heating and drying of the green sheet.

[0011]

According to the present invention, when a water-soluble polyvinyl acetal resin is used as the binder resin, the flexibility of the green sheet is increased, but the heat sealability is not improved even if the amount of ethylene glycol as the plasticizer is increased. The reason is,
When the slurry is applied to the support and dried, ethylene glycol is volatilized together with water by azeotropic distillation or the like, and the amount of the ethylene glycol on the surface of the green sheet is reduced. . On the other hand, according to the present invention, when glycols having a boiling point of 230 ° C. or more are used as the plasticizer, the plasticizer effectively remains on the green sheet surface even during vacuum defoaming or water drying of the slurry. As a result, it is considered that a green sheet having excellent heat-fusibility can be obtained.

[0012]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by these examples. Example 1 20 g of a water-soluble polyvinyl acetal resin (polymerization degree: 500, saponification degree: 88 mol%, butyralization degree: 10 mol%) was dissolved in 140 g of water, and 4 g of glycerin (boiling point: 290 ° C.) as a plasticizer and alumina powder were dissolved therein. 200 g was added and mixed for about 15 hours in a ball mill.

The obtained slurry is heated to 40 ° C., defoamed and concentrated by an aspirator, applied to a release-treated polyester film to a thickness of about 0.5 mm, and air-dried for one day. And dried in a gear oven at 110 ° C. for about 3 hours to obtain a green sheet having a thickness of about 0.15 mm. Example 2 In the same manner as in Example 1, except that 20 g of a water-soluble polyvinyl acetal resin (polymerization degree: 800, saponification degree: 95 mol%, butyralization degree: 8 mol%) was used and 8 g of glycerin was used as a plasticizer. A green sheet having a thickness of about 0.2 mm was obtained. Example 3 Water-soluble polyvinyl acetal resin (polymerization degree: 1000, saponification degree: 88 mol%, acetoacetalization degree: 15 mol%)
A green sheet having a thickness of about 0.2 mm was obtained in the same manner as in Example 1, except that 20 g was used and 6 g of glycerin and 2 g of ethylene glycol were used as plasticizers. Example 4 Diethylene glycol (boiling point: 245 ° C.) 8 as a plasticizer
g in the same manner as in Example 1 except that g was used.
A 5 mm green sheet was obtained. Comparative Example 1 8 g of ethylene glycol (boiling point: 197 ° C.) as a plasticizer
Approximately 0.15 in the same manner as in Example 1 except that
mm green sheet was obtained. Comparative Example 2 Trimethylene glycol (boiling point: 214 ° C.) as a plasticizer
Except for using 8 g, a thickness of about 0.
A 2 mm green sheet was obtained.

The following measurements were performed on each of the green sheets obtained as described above. A test piece (distance between marked lines: 20 mm) was prepared by punching a green sheet for measuring strength and elongation into a No. 2 dumbbell according to JIS K 6301.
After standing overnight at 50 ° C. and a relative humidity of 50%, the breaking strength and the breaking elongation were evaluated by measuring with an oak graph at a tensile speed of 100 mm / min. A test piece of 50 mm square was cut out from the green sheet for evaluation of heat fusing property, and ten pieces of the test piece were laminated. Then, a pressure of 100 kg / cm ² was applied at 100 ° C., and press molding was performed for 10 minutes. The cross section was visually observed, and the case where the laminated surface was not seen was regarded as good, and the case where it was clearly seen was regarded as bad.

The above results are shown in Table 1.

[0016]

[Table 1]

Claims (1)

(57) [Claims] 1. An aqueous ceramic binder comprising, as main components, a water-soluble polyvinyl acetal resin and glycols having a boiling point of 230 ° C. or higher.