JPS60122770A - Binder for ceramic forming - 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 The present invention relates to a binder used for molding so-called ceramics such as alumina, barium titanate, ferrite, etc., and particularly to a water-based binder for molding ceramics that does not use an organic solvent.

The dry press molding method is used to form ceramics.

There are doctor blade methods, extrusion molding methods, etc., but the various binders used in these molding methods have many drawbacks.

The dry press molding method involves spray-drying a slurry prepared by mixing ceramic powder such as alumina with water, a lubricant, a binder, a plasticizer, etc., and then filling a mold with a granulated ceramic composition and pressing it. This is a method of molding. As the binder used in this molding method, generally vinyl alcohol, methyl cellulose, and Na salt of carboxyl methyl cellulose are used. However, the granules obtained using these binders are hard, and therefore press pressure must be increased, which increases mold wear and shortens mold life.
Although it is possible to slightly soften the -C granules and reduce the press pressure by using a plasticizer such as glycol in combination with a binder, it is possible to reduce the press pressure by using a plasticizer such as glycol. As a result, shrinkage during binder removal, which is the binder removal process before firing, increases, causing deformation and cracking such as blisters and distortions, as well as decreasing bonding strength and weakening mechanical strength. Undesirable. Furthermore, during storage after molding, the plasticizer may precipitate on the surface or volatilize, causing brittleness. In addition, the Na salts of polyvinyl alcohol, methylcellulose, and carboxymethylcellulose have poor thermal decomposition properties, and a large amount of ash containing carbon and alkali metals such as Na remains, which cannot be decomposed or burned out in one step of debinding, and It may cause deformation such as cracks, cracks, or scratches, and it may cause loss of electrical properties such as electrical insulation when used as electronic components such as IC boards, IC packages, and dielectric materials. . Furthermore, these binders have high hygroscopicity, and moisture absorption after molding reduces mechanical strength, causing breakage during storage and handling before binder removal.

In the dog tarp 1/-do method, ceramic powder is mixed with organic solvent 1
In this method, a slurry prepared by mixing with a dispersant, a plasticizer, an organic solvent binder, etc. is cast onto a carrier film by adjusting the thickness with a doctor blade, and is dried and formed into a tape-like green sheet. . Doltrichloroethylene, isopropyl alcohol as organic solvents.

Ethyl alcohol and the like are used, but there are many problems such as explosion due to ignition, fire danger, odor during molding, toxicity to the human body, and pollution problems due to evaporated organic gas during drying. Additionally, it will be necessary to install explosion-proof equipment, waste gas treatment equipment, solvent recovery equipment, etc. Polyvinyl butyl is generally used as an organic solvent-based binder, but it has poor thermal decomposition properties and ash content such as carbon and Na that remains after binder removal causes the same problems as binders for press molding. There is. In addition, the extrusion molding method requires the use of plasticizers such as phthalate esters, and the molded products become brittle due to precipitating and volatilization of the plasticizer on the surface during storage after molding. In this method, a binder, a plasticizer, etc. are mixed, and the mixture is extruded using an extrusion molding machine. In addition to binders, methyl cellulose, hydroxyethyl cellulose, and polyvinyl alcohol are generally used, but they have poor thermal decomposition properties and the same problems as binders for press molding occur due to the ash of carbon, Na, etc. that remains after the binder is removed. ing.

In view of the current situation, the present inventors have developed a piezoelectric system that can be used in press molding methods, doctor blade methods, extrusion molding methods, etc. As a result of intensive research to solve these problems of goo, we found (1) (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms and an alkylene group having 1 to 4 carbon atoms; At least one monomer selected from the group consisting of (meth)acrylic acid alkoxyalkyl esters 3
0 to 85 weight ratio, (2) general formula (R, , R2, and R3 are each hydrogen or methyl group, n is an integer of 1 or more), or R5 is hydrogen or methyl group, R6 is hydrogen or an alkyl group having 1 to 4 carbon atoms; m represents an integer of 2 or more;

) at least one monomer selected from the group consisting of (meth)acrylic esters represented by (5 to 60% by weight); (3) a carboxyl group-containing monomer (0 to 60% by weight);
and (4) a monomer copolymerizable with these: 0 to 60
It was discovered that a binder for ceramic molding obtained by copolymerizing % by weight (however, the total of all monomers is 100% by weight) satisfies such requirements, and the present invention was completed. .

In other words, the present invention reduces the press pressure in the press molding method,
Improving moldability and hygroscopicity, and improving moldability with a doctor blade.In the de-method, the transition from a solvent-based system to a water-based system that is safe and hygienic, and improved thermal decomposition properties: In the extrusion molding method, improvements in thermal decomposition properties and moldability were achieved, respectively. The purpose is to provide a binder for the top two mix molding.

In the following description, (meth)acrylic acid refers to acrylic acid and/or methacrylic acid, and (meth)acrylate refers to acrylate and/or methacrylate.

Examples of the (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms used in the present invention include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, and n-butyl (meth)acrylate. .

Isobutyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate + n-dodecyl (meth)acrylate, stearyl (meth)acrylate, etc. can be used.

Examples of the (meth)acrylic acid alkoxyalkyl ester having an alkyl group having 1 to 4 carbon atoms include tomethy, oxymethyl (meth)acrylate, methoxyethyl (meth)acrylate-1-, and ethoxymethyl (meth) Acrylate, Ethoxyethyl (meth)acrylate, Ethoxybutyl (meth)acrylate, Butoxyethyl (
meth)acrylate, etc. can be used.

At least one selected from the group consisting of (meth)acrylic acid alkyl esters having no alkyl group having 1 to 20 carbon atoms and (meth)acrylic acid alkoxyalkyl esters having an alkylene group having 1 to 4 carbon atoms. One type of monomer is a fully copolymerized monomer, Zimmer 100 weight Ik 迿中3
A ratio ranging from 0 to 85 parts by weight must be used.

If the ratio is less than 30% by weight, the thermal decomposition property is reduced, the resin becomes hard and the pressure increases, and the binding strength as a binder is reduced. If the ratio exceeds 85% by weight, the hydrophilicity decreases, the amount of wetting and adsorption to ceramic powder decreases, and the binding strength as a binder decreases. Monomers represented by the general formula (R, R2 and R3 are each hydrogen or methyl group, n is an integer of 1 or more) include polyethylene glycol di(meth)acrylate, polyprolene glycol di(meth)acrylate, etc. can be mentioned. The general formulas each represent hydrogen or a methyl group, R6 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, and m represents an integer of 2 or more. ) is represented by ゛7
- as polyethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, methoxypolypropylene mono(methanoacrylate, methoxypolyethylene glycol mono(meth)acrylate, ethoxypolypropylene glycol mono(meth)acrylate, ethoxypolyethylene glycol Examples include mono(meth)acrylate, n-butoxypolypropylene glycol mono(meth)acrylate, n-butoxypolyethylene glycol mono(meth)acrylate, etc. At least one monomer represented by these general formulas is fully copolymerized. It must be used in a proportion ranging from 5 to 60% by weight based on 100% by weight of the monomer.If the proportion is less than 5 parts by weight, the hydrophilicity decreases and the amount of wetting and adsorption to ceramic powder decreases, resulting in poor binding as a binder. Strength: decreases or becomes hard, requiring increased press pressure. Also, if the ratio exceeds 600 parts by weight, hygroscopicity increases and the mechanical strength of the molded product decreases.

Examples of carboxyl group-containing monomers include (meth)acrylic acid, maleic acid, itaconic acid, and maleic acid half esters such as monoisoglobil maleate.

Monomers having at least one carboxyl group in one molecule can be used, such as itaconic acid half ester. These carboxyl group-containing monomers may be used in an acid state, or may be partially or completely neutralized with ammonia or an organic amine. Examples of such organic amines include monoethylamine, diethylamine, mono- n-propylamine, di-n-propylamine, mono-n-butylamine, di-n-butylamine, monoethanolamine, jetanolamine, triethanolamine, triethylenediamine, triethylenetetramine, hexamethylenediamine, hexamethylenetetramine , pyridine, piperidine.

Low molecular weight amines such as polydimethylaminoethyl methacrylate, and high molecular weight amines such as a condensate of alkylene dichloride and alkylene polyamine can be used.

Such ≠ruboxyl group-containing monomers must be used in a proportion ranging from 5 to 60% by weight based on 100% by weight of the total copolymerized monomers. If the ratio is less than 5% by weight, the hydrophilicity decreases, the amount of wetting and adsorption to ceramic powder decreases, and the binding strength as a binder decreases. If the ratio exceeds 600 parts by weight, the thermal decomposition property may be decreased, the press pressure may be increased due to the hardness, and the binding strength as a binder may be decreased. Hygroscopicity also increases.

Monomers copolymerizable with these include 2-lobane (
meth)acrylate, pentaerythritol (meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, (meth)acrylonitrile, acrylamide, N-methylolacrylamide, styrene, α- Methylsulfide, ethylene, vinyl chloride.

Vinyl vinegar and the like can be used.

Such a copolymerizable 7-mer is used as necessary, and has a content of θ to 60% based on the total weight of 100 copolymerized monomers.
It is a ratio of % by weight. If the ratio exceeds 600 parts by weight, the ratio of other essential copolymerizable monomers will fall below the lower limit, and the above-mentioned problems will occur.

There is no particular restriction on the polymerization method for obtaining the ceramic molding inder of the present invention, and conventionally known polymerization methods can be used.

The binder for ceramic molding of the present invention obtained in this way may be used as a binder as it is,
Alternatively, it may be used after being appropriately neutralized with ammonia or the above-mentioned organic amines.

The ceramic molding binder of the present invention reduces press pressure, improves moldability, and moisture absorption in press molding; transitions from solvent-based to safe and sanitary water-based, and improves thermal decomposition properties in doctor blade method; extrusion In the molding method, thermally decomposable,
Each of these can improve moldability.

The present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. In addition, all parts in the examples indicate parts by weight, and all 忤 indicates parts by weight.

Example 1 (Synthesis of binder) In a separable flask equipped with a stirrer, a thermometer, a cooling tube, a nitrogen introduction tube, a mixing monomer dropping funnel, and a polymerization initiator dropping funnel, 150 parts of distilled water and polyoxyethylene nonyl as an emulsifier were placed. Phenyl ether (HLB18.2
3 parts of Kao Soap (manufactured by Kao Soap Co., Ltd.) were charged, and a large amount of nitrogen was introduced through the nitrogen introduction tube to create a nitrogen atmosphere inside the flask. Next, the mixed monomer was added dropwise to the funnel, and 100 parts of a mixed monomer consisting of 20 parts of ethyl acrylic l/-460 parts, polyethylene glycol monomethacrylate PE-200 (manufactured by NOF C), m = 4-5), and 20 parts of methacrylic acid was added.
20 parts of a 2% t-butyl hydroperoxide aqueous solution was charged into the polymerization initiator dropping funnel. While adjusting the internal temperature of the flask to 80°C, the mixed monomer and polymerization initiator were added dropwise over 2 hours, heated at 80°C for 1 hour, cooled, and adjusted to pH 8.0 with aqueous ammonia until the solid content concentration was 35. % of a water-based binder for ceramic molding was obtained.

The ash content and Na content of this binder were measured and the results are shown in Table 1.

For the ash content, put a dry binder in a platinum crucible and
It was incinerated in an electric furnace at 0° C. in an air atmosphere for 42 hours, and its weight was measured.

The Na content was measured by dissolving a part of the above ash with mineral acid and using an atomic absorption spectrophotometer.

Example 2 (Ceramics molding) Alumina (AI, -1608G, purity 99.0, average particle size 0.4 tr, Showa Light Metal (copper) 100 parts, distilled water 40 parts 9 Dispersant (Aqualic NL, Japan) 02 parts of Catalyst Kagaku Kogyo (made of copper, ammonium polyacrylate) and 20 parts of the aqueous binder for 35% ceramic molding obtained in Example 1 were mixed in a ball mill for 24 hours, and the resulting slurry was spray-dried to give an average Particle size 100μ
granules were obtained. The granules were filled into a mold and 500kf/
c++! , 1000 Yu/i, and 1501/d to obtain a molded product having a thickness of 3 mm, a width of 10 mm, and a length of 30 mm. The releasability from the mold and the surface smoothness of the molded product were good. These molded products, green density, bending strength,
The hygroscopicity was measured and the results are shown in Table 1.

The bending strength was measured using an Instron strength testing machine model 1102 at a span width of 20 ma and a head speed of 0.51 minutes.

The evaluation of hygroscopicity was based on the weight increase rate after humidifying a molded product obtained at a press pressure of 1000 kt/ctl for 24 hours at 20°C and 65% relative humidity, and the weight increase rate at 20°C and 95% relative humidity.
The weight increase rate was measured after humidification for 4 hours.

Comparative Example 1 A molding product was obtained in the same manner as in Example 2 except that 100 parts of Flumina (AL-1608G) was subjected to Tehyintertight and 7 parts of polyvinyl alcohol (GL-05, manufactured by Nippon Gosei Kagaku Co., Ltd.) was used. The green density, bending strength, and hygroscopicity of the molded products were measured. Incidentally, the ash content and Na content of polyvinyl alcohol were also measured. Ash content and Na content are the upper 2 of Example 1.
It is considerably more than the binder for mix molding. Also,
The press pressure also had to be higher than in Example 2 to obtain the same green density. Furthermore, the bending strength was low and the hygroscopicity was high at the same green density. These results are shown in Table 1.

Comparative Example 2 Polymerization and molding were carried out in the same manner as in Example 1 and Example 2, except that 100 parts of a mixed monomer consisting of 25 parts of ethyl acrylate, 10 parts of polyethylene glycol monomethacrylate (PE-200) and 65 parts of methacrylic acid was used. The ash content and Na content of the resulting binder, as well as the green density, bending strength, and hygroscopicity of the molded products were measured, and the results are shown in Table 1.

Compared to Example 1, the ash content was higher, the hygroscopicity was higher, the pressing pressure was higher, and the bending strength was lower.

Example 3 (Synthesis of binder) Polymerization was carried out using the same apparatus as in Example 1. A flask was first charged with 100 parts of distilled water and 2 parts of ammonium salt of polyoxyethylene sulfate (Hitenol N-gB, manufactured by Daiichi Kogyo Seiyaku (Sakaki)).

Next, the mixed monomers were added dropwise: 10 parts of rotohestearyl methacrylate, 10 parts of ethyl acrylic l/-), 20 parts of 2-methoxyethyl acrylate, methoxyboriethelene glycol monomethacrylate M-90G, manufactured by Shin Nakamura Chemical Co., Ltd., m= 9) Charge 100 parts of a mixed monomer consisting of 40 parts and 20 parts of methacrylic acid, and add 20 parts of a 2% t-butyl hydroperoxide aqueous solution to the polymerization initiator dropping funnel.
I have prepared a section. While adjusting the internal temperature of the flask to 80°C, the mixed monomers and polymerization initiator were added dropwise over 2 hours each, heated at 80°C for 1 hour, cooled, and adjusted to pi (s, o) with ammonia water to form a solid. An aqueous binder for ceramic molding having a concentration of 45 cm was obtained.The ash content and Na content of this binder are shown in Table 2.

Example 4 (Molding of ceramics) 100 parts of alumina (AL-1608G), 40 parts of distilled water, 0.2 parts of dispersant (Aqualic NL), and the 45% water-based binder obtained in Example 3 for molding ceramics. 30 parts were mixed in a ball mill for 24 hours, and the resulting slurry was degassed under reduced pressure and placed on silicone-coated release paper to a thickness of 1.5 tons.
I did the casting.

Next, the mixture was heated from 60'C to 120'C at a heating rate of 120'C/min, and dried to a moisture content of 0.1% or less to produce a flexible green sheet in the form of a tape.

The green density and tensile properties of the sheet were measured. Tensile properties were determined by punching the sheet into a dumbbell size 3 shape (JISK6301).
Tensile strength, elongation at break, and strength were measured at a tensile speed of 0.5 cm/min. These results are shown in Table 2.

Comparative Example 3 100 parts of aluminum t (AL-1608G), 13.5 parts of polyvinylbutylene (3oooK, manufactured by Denki Kagaku Kogyo Co., Ltd.) as a binder, 5 parts of n-octyl phthalate as a plasticizer, 9 glyceryl as a dispersant trioleate 0
．． A green sheet was prepared in the same manner as in Example 4, and its green density and tensile properties were measured.

In addition, the ash content and N content of polyvinylbutylene were also measured. These results are shown in Table 2. Both the ash content and the Na content were higher than that of the binder for ceramic molding of Example 3.

Comparative Example 4 Same as Example 3 except that 100 parts of a mixed monomer consisting of 30 parts of stearyl methacrylate, 13 parts of ethyl acrylate, 25 parts of 2-methoxyethyl acrylate, 30 parts of methoxypolyethylene glycol monomethacrylate, and 2 parts of methacrylic acid was used. Polymerization was carried out, and pns and oVc were adjusted with aqueous ammonia to obtain a binder.

An attempt was made to obtain a green sheet using this binder in the same manner as in Example 4, but the sheet developed cracks during drying.

Example 5 (Synthesis of binder) Polymerization was carried out using the same apparatus as in Example 1. Into a mixing monomer dropping funnel were 15 parts of n-butyl methacrylate, 5 parts of polyethylene glycol diacrylate ester A-4G (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., n=4), and polypropylene glycol monomethacrylate H3 Mar PP-1000, Japan. Manufactured by Yushi Co., Ltd., n=5-6)
30 parts of styrene, and 100 parts of a mixed monomer consisting of 30 parts of styrene and 20 parts of acrylic acid were added to the initiator dropping funnel.
20 parts of ammonium 1persulfate aqueous solution was charged.

Next, while adjusting the internal temperature of the flask to 95°C, the mixed monomers and polymerization initiator were added dropwise over 2 hours each, heated at 95°C for an additional 30 minutes, cooled, and pH-controlled with aqueous ammonia.
An aqueous binder for ceramic molding with a solid content concentration of 2° was obtained by adjusting the solid content to 7.0.

Example 6 (Molding of ceramics) Barium titanate (KYORIX A, Kyoritsu Ceramics Raw Materials)
Co., Ltd.) 100 parts, 40 parts of distilled water, 0.2 parts of a dispersant (Aquarik NL), 2 parts of stearic acid as a lubricant, and 15 parts of the aqueous binder for ceramic molding with a concentration of 20% obtained in Example 5. were mixed using a universal mixer (5 parts MV type, manufactured by Sanei Seisakusho). Next, mix the mixture with a continuous kneader (manufactured by Kurimoto Iron Works) to a diameter of approximately 5J11! It was extruded into a rod shape.

The obtained extruded product was heated to 60°C and the heating rate was 1°C/min.
Heat to 20℃ and then heat at 120℃ for 30 minutes.
It was dried to a moisture content of 0.1 inch or less. After drying, cut it and polish the top and bottom circular planes with sandpaper to a length of 1.
It was made into a cylindrical shape and its longitudinal crushing strength was measured. The results are shown in Table 3. The crushing strength was measured using a Honya type hardness meter (manufactured by Honya Seisakusho).

Comparative Example 5 Extrusion molding was carried out in the same manner as in Example 6 using 3 parts of methyl cellulose (Marborose M-600, manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.) as a binder to 100 parts of barium titanate (KYOR, IX A). After that, the crushing strength was measured. The ash content and Na content of methylcellulose were also measured, and the results are shown in Table 3.

Compared to the binder for ceramic molding of Example 5, the ash content and Na content were both higher.

Comparative Example 6 Mixed monomer 100 consisting of 10 parts of n-butyl methacrylate, 5 parts of polyethylene glycol diacrylate (NK Ester A-46), 18 parts of polypropylene glycol monomethacrylate (Premmar PP-1000), 65 parts of styrene, and 2 parts of acrylic acid Polymerization was carried out in the same manner as in Example 5 except for using
, 0 and used for extrusion molding. Also, the ash content of this binder.

The Na content and the crushing strength of the molded product were measured. The results are shown in Table 3. Compared to Example 6, the ash content was higher and the crushing strength was lower.

Claims (1)

[Claims] 1. (1) Having an alkyl group having 1 to 20 carbon atoms (
At least one selected from the group consisting of meth)acrylic acid alkyl ester and (meth)acrylic acid alkoxyalkyl ester having an alkylene group having 1 to 4 carbon atoms.
Seed monomer 30-85% by weight. (2) General formula (R, R2 and R3 are each hydrogen or a methyl group, n is an integer of 1 or more.) (R4 and R5 are each hydrogen or a methyl group, R6 is hydrogen or a carbon number of 1 to 4 an alkyl group, m represents an integer of 2 or more.)
(3) a carboxyl group-containing monomer (5 to 60% by weight); and (4) copolymerization with these. A binder for ceramic molding obtained by copolymerizing possible monomers with a weight ratio of 0 to 60 (however, the weight is based on the total weight of all monomers).