JP5301691B2 - Dispersant for ceramic extrusion - Google Patents

Description

  The present invention relates to a dispersant (ceramic extrusion molding dispersant) used for producing a ceramic molded body by extruding a composition containing ceramic particles, a binder, a dispersant and water and then firing the composition.

  Conventionally, as a dispersant for ceramic extrusion molding, a dispersant comprising a copolymer of methyl polyoxyethylene (average polymerization degree 10.8) monoallyl ether and maleic anhydride, a sodium salt or an ammonium salt of this copolymer ( And a dispersant comprising dimethylaminoethanol salt or triethylamine salt of methylpolyoxyethylene (n = 4 or 9) methacrylate, methacrylic acid, 2-hydroxyethyl methacrylate and methyl methacrylate copolymer (see Patent Document 2) For example).

Japanese Patent Application Laid-Open No. 07-25665 JP-A-60-155567

  However, when a conventional ceramic extrusion molding dispersant increases the extrusion molding speed (about 8.0 to 15 mm / s), the extrusion load becomes too large to be molded, or the surface of the extruded molded body becomes rough. There is a problem that cracks occur. Therefore, an object of the present invention is to provide a ceramic extrusion molding dispersant having a small extrusion load and good moldability even when the extrusion molding speed is increased.

｛式中、Ｒ^１は（メタ）アクリロイル基、Ｏは酸素原子、ＡＯは炭素数２〜４のオキシア
ルキレン基、ｐは２１〜２００の整数、Ｘは水素原子又は炭素数１〜１２のアルキル基を表す。｝ The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems.
That is, the feature of the dispersant for ceramic extrusion molding of the present invention is that the dispersant is used for producing a ceramic molded body by extruding a composition containing ceramic particles, a binder, a dispersant and water, followed by firing. In
A vinyl polymer (P) having (meth) acrylic acid (salt) (A) and a vinyl monomer (B) represented by formula (1) as an essential constituent monomer, wherein (meth) acrylic acid (salt) Based on the number of moles of (A) unit and vinyl monomer (B) unit, the content (mol%) of (meth) acrylic acid (salt) (A) unit is 72 to 98, the content of vinyl monomer (B) unit The gist is that it contains a vinyl polymer (P) having an amount (mol%) of 2 to 28.

{In the formula, R ¹ is a (meth) acryloyl group, O is an oxygen atom, AO is an oxyalkylene group having 2 to 4 carbon atoms, p is an integer of 21 to 200, X is a hydrogen atom or an alkyl having 1 to 12 carbon atoms Represents a group. }

  The dispersant for ceramic extrusion molding of the present invention is excellent in extrusion moldability, and a good ceramic molded body can be obtained even when the extrusion speed is increased.

"(Meth) acryl ..." means "acryl ..." and / or "methacryl ...".
“... acid (salt)” means “... acid” and / or “... acid salt”.
Examples of the salt include alkali metal salts, alkaline earth metal salts, ammonium salts, and organic amine salts.
These may be a mixture of two or more.

As (meth) acrylic acid (salt) (A), publicly known (meth) acrylic acid (salt) (JP, 2005-154266, etc.) etc. can be used.
Of the known (meth) acrylic acid (salt), from the viewpoint of extrusion moldability and the like, (meth) acrylate is preferable, more preferably (meth) acrylic acid alkali metal salt, and particularly preferably (meth) acrylic acid. Sodium salt, most preferably sodium methacrylate.

In the formula (1), a methacryloyl group is preferred among the (meth) acryloyl groups (R1).
Examples of the oxyalkylene group having 2 to 4 carbon atoms (AO) include oxyethylene, oxypropylene, and oxybutylene. Of these, oxyethylene and oxypropylene are preferable from the viewpoint of extrusion moldability and the like, and more preferably oxyethylene. (AO) p may be one kind of oxyalkylene group or a mixture of two or more kinds. When two or more kinds are mixed, the bonding form may be any of block form, random form, and a mixture thereof.
p is an integer of 21 to 200, preferably an integer of 25 to 190, more preferably an integer of 30 to 180, and particularly preferably an integer of 40 to 150 from the viewpoint of extrudability and the like.

Of the hydrogen atom or alkyl group (X) having 1 to 12 carbon atoms, the alkyl group having 1 to 12 carbon atoms may be a linear alkyl group {methyl, ethyl, n-butyl, n-hexyl, n-octyl, n -Decyl, n-undecyl and n-dodecyl and the like} and branched alkyl {isopropyl, t-butyl, 2-ethylhexyl, isodecyl and isododecyl and the like}.
Of these, a linear alkyl group is preferable, and methyl, ethyl, n-butyl, n-hexyl and n-octyl are more preferable.

Examples of the vinyl monomer (B) which is a compound represented by the formula (1) include alkyl polyoxyalkylene (meth) acrylate and polyoxyalkylene glycol mono (meth) acrylate. 289844, etc.) can be used as they are.
Of the known vinyl monomers, alkylpolyoxyalkylene (meth) acrylate is preferable from the viewpoint of extrudability and the like, more preferably alkylpolyoxyalkylene (2 to 3 carbon atoms) (meth) acrylate, and still more preferably. Alkyl (1-6 carbons) polyoxyalkylene (2-3 carbons) (meth) acrylate, particularly preferably alkyl (1-6 carbons) polyoxyethylene (meth) acrylate, most preferably alkyl (carbons) 1-6) Polyoxyethylene methacrylate.

The vinyl monomer (B) can be produced by a known method (Japanese Patent Laid-Open No. 2005-289844) or the like, but a commercially available product may be used.
Commercially available products include Blemmer (registered trademark) PME series {PME-1000 (methyl polyoxyethylene methacrylate: in formula (1), AO = oxyethylene, p = 23, X = methyl) and PME- 4000 (methyl polyoxyethylene methacrylate: general formula (1), AO = oxyethylene, p = 90, X = methyl, etc.)} and Kyoeisha Chemical Co., Ltd. light ester 041MA (methyl polyoxyethylene methacrylate: formula (1) , AO = oxyethylene, p = 30, X = methyl) and the like.

The content (mol%) of the (meth) acrylic acid (salt) (A) unit is the moles of the (meth) acrylic acid (salt) (A) unit and the vinyl monomer (B) unit from the viewpoint of extrusion moldability and the like. Based on the number, 72-98 are preferred, more preferably 80-97, then more preferably 82-96, particularly preferably 84-95.

  The content (mol%) of the vinyl monomer (B) unit is 2 based on the number of moles of the (meth) acrylic acid (salt) (A) unit and the vinyl monomer (B) unit from the viewpoint of extrusion moldability and the like. -28 are preferable, More preferably, it is 3-20, Next, More preferably, it is 4-18, Most preferably, it is 5-16.

In addition to (meth) acrylic acid (salt) (A) and vinyl monomer (B), other vinyl monomer (C) may be used as a constituent monomer for vinyl polymer (P).
The other vinyl monomer (C) is not particularly limited as long as it can be copolymerized with (meth) acrylic acid (salt) (A) and vinyl monomer (B), but (meth) acrylamide, alkyl (meth) acrylic. Examples include esters, hydroxyalkyl (meth) acrylic esters, polyalkylene glycols (addition moles 1 to 20) mono (meth) acrylic esters, and cationic (meth) acrylic esters. As these vinyl monomers, known monomers (Japanese Patent Application Laid-Open No. 2005-154266) can be used.

  Among these, from the viewpoint of extrudability and the like, alkyl (meth) acrylic ester, hydroxyalkyl (meth) acrylic ester, polyalkylene glycol (addition mole number 1 to 20) mono (meth) acrylic ester and cationic (meth) Acrylic esters are preferred, more preferably alkyl (meth) acrylic esters, hydroxyalkyl (meth) acrylic esters and polyalkylene glycols (addition moles 1 to 20) mono (meth) acrylic esters, particularly preferably polyalkylene glycols (addition moles). (Equation 1-20) Mono (meth) acrylic ester monomer.

  When the other vinyl monomer (C) is used as a constituent unit, the content (mol%) of the other vinyl monomer (C) unit is (meth) acrylic acid (salt) (A) from the viewpoint of extrusion moldability and the like. Based on the number of moles of units and vinyl monomer (B) units, 0.1 to 28 are preferred, more preferably 0.2 to 17, then more preferably 0.3 to 14, particularly preferably 0.4 to. 11.

The weight average molecular weight (Mw) of the vinyl polymer (P) is preferably 10,000 to 1,800,000, more preferably 50,000 to 1,000,000, particularly preferably from the viewpoint of extrusion moldability and the like. 100,000 to 800,000.
The weight average molecular weight is measured by gel permeation chromatography (GPC) method (standard substance: polyethylene glycol).

The vinyl polymer (P) can be easily obtained by a known polymerization method {solution polymerization, suspension polymerization, bulk polymerization, reverse phase suspension polymerization, emulsion polymerization or the like}.
Of the known polymerization methods, solution polymerization, suspension polymerization, reverse phase suspension polymerization and emulsion polymerization are preferred, more preferably solution polymerization, reverse phase suspension polymerization and emulsion polymerization, particularly preferably solution polymerization and emulsion polymerization. Solution polymerization is preferred.
For the polymerization, known polymerization initiators, chain transfer agents, and / or solvents can be used.
When using a solvent, the obtained vinyl polymer (P) solution (suspension or emulsion) may be used as the dispersant of the present invention as it is. On the other hand, the solvent may be distilled off from the solution, suspension or emulsion to form the dispersant of the present invention, or the solvent may be replaced with another solvent (for example, water) to form the dispersant of the present invention. Good.

  When vinyl polymer (P) is a salt, vinyl polymer (P) may be produced using (meth) acrylate, or after obtaining vinyl polymer using (meth) acrylic acid, alkali It is good also as a salt by mixing with (for example, Unexamined-Japanese-Patent No. 2001-152199). Of these methods, the latter is preferred.

  The dispersant of the present invention may contain a solvent in addition to the vinyl polymer (P). As the solvent, known solvents (JP 2004-203705 A, JP 2002-37673 A, etc.) can be used, and water is preferable. When the solvent is contained, the content (% by weight) may be appropriately selected from the viewpoint of ease of handling, but is preferably 5 to 300 based on the weight of the vinyl polymer (P).

  The dispersant of the present invention may contain a binder and / or a known dispersant in addition to the vinyl polymer (P). As the binder and the known dispersant, known ones (JP 2004-203705 A, JP 2002-37673 A, etc.) can be used. When a binder and / or a known dispersant is contained, the content (% by weight) may be appropriately selected from the viewpoint of ease of handling, but is preferably 5 to 2000 based on the weight of the vinyl polymer (P). .

  The dispersing agent for ceramic extrusion molding of the present invention is suitable as a dispersing agent used for producing a ceramic molded body by extruding a composition containing ceramic particles, a binder, a dispersing agent and water, followed by firing. .

As a method for producing a ceramic molded body using the dispersant for ceramic extrusion molding of the present invention, a known method (Japanese Patent Laid-Open No. 2002-37673, etc.) can be applied, and the dispersant, ceramic particles and binder of the present invention can be applied. And a step of obtaining an extruded product by extruding the composition containing water and a step of obtaining a fired product by firing the extruded product.
In addition, the step of obtaining the fired body includes a cooling operation after firing, and may further include a step of machining the fired body to obtain a ceramic molded body if necessary. {If this step is not included, the fired body remains as it is. It becomes a ceramic molded body. }.

As the ceramic particles and the binder, known ones (JP 2004-203705 A, JP 2002-37673 A, etc.) can be used.
Examples of water include tap water, industrial water, ground water, distilled water, ion exchange water, and ultrapure water.

  The amount of the dispersant of the present invention can be variously changed depending on the type of ceramic particles, the extrusion speed of the extruded product, the die shape, etc., but from the viewpoint of extrusion moldability, etc., with respect to 100 parts by weight of the ceramic particles, 0.05-7 weight part is preferable, More preferably, it is 0.2-5 weight part.

  A composition containing ceramic particles, a binder, a dispersant for ceramic extrusion molding according to the present invention and water is further known as necessary (JP 2004-203705 A, JP 2002-37673 A, etc.) A solvent may be contained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. In the following, “parts” and “%” respectively represent “parts by weight” and “% by weight” unless otherwise specified.

<Production Example 1>
A SUS autoclave equipped with a thermometer and a stirrer was charged with 292 parts of methanol (special grade JIS reagent manufactured by Nacalai Tesque Co., Ltd.) and 3.21 parts of sodium hydroxide. The temperature was raised to ° C. 1 210 parts ethylene oxide
After a blow reaction at 00 ° C. for 1 hour, the temperature was raised to 180 ° C., and 4210 parts of ethylene oxide was blown and reacted at 180 ° C. for 1 hour. Further, after aging at 180 ° C. for 1 hour, the mixture was cooled to 25 ° C. Transfer the contents to a glass reactor equipped with a thermometer, stirrer, product water separator, reflux condenser, 13.7 parts hydroquinone, 91.5 parts sulfuric acid, 1960 parts methacrylic acid and 1990 parts toluene, The temperature was raised to 115 ° C. At this temperature, the reaction was continued until the product water was not separated into the product water separator, and then toluene was distilled off at 0.1 kPa and 115 ° C. Subsequently, it cooled to 25 degreeC and methyl polyoxyethylene (addition mole number 21 mol) methacrylate {vinyl monomer (b1)} was obtained.

<Production Example 2>
“Methanol 292 parts”, “ethylene oxide 4210 parts” and “ethylene oxide 4210 parts” were changed to “hexanol 928 parts”, “ethylene oxide 36100 parts” and “ethylene oxide 36100 parts” in the same manner as in Production Example 1, Hexyl polyoxyethylene (addition mole number 180 mol) methacrylate {vinyl monomer (b2)} was obtained.

<Production Example 3>
Except that “methanol 292 parts”, “ethylene oxide 4210 parts” and “ethylene oxide 4210 parts” were changed to “decanol 1440 parts”, “ethylene oxide 30100 parts” and “ethylene oxide 30100 parts”, in the same manner as in Production Example 1, Decyl polyoxyethylene (addition mole number 150 mol) methacrylate {vinyl monomer (b3)} was obtained.

<Production Example 4>
“Methanol 292 parts”, “ethylene oxide 4210 parts” and “ethylene oxide 4210 parts” were changed to “octanol 1180 parts”, “ethylene oxide 38100 parts” and “ethylene oxide 38100 parts” in the same manner as in Production Example 1, Octyl polyoxyethylene (addition mole number 190 mol) methacrylate {vinyl monomer (b4)} was obtained.

<Production Example 5>
“Methanol 292 parts”, “ethylene oxide 4210 parts”, “ethylene oxide 4210 parts” and “methacrylic acid 1960 parts” were replaced by “decanol 1440 parts”, “ethylene oxide 6010 parts”, “ethylene oxide 6010 parts” and “acrylic acid 1640 parts”. In the same manner as in Production Example 1, except for changing to decyl polyoxyethylene (addition mole number 30 mol) acrylate {vinyl monomer (b5)} was obtained.

<Production Example 6>
Methyl polyoxyethylene (added mole number 200 mol) methacrylate in the same manner as in Production Example 1 except that “ethylene oxide 4210 parts” and “ethylene oxide 4210 parts” were changed to “ethylene oxide 40100 parts” and “ethylene oxide 40100 parts”. {Vinyl monomer (b6)} was obtained.

<Production Example 7>
Except that “methanol 292 parts”, “ethylene oxide 4210 parts” and “ethylene oxide 4210 parts” were changed to “dodecanol 1690 parts”, “ethylene oxide 5010 parts” and “ethylene oxide 5010 parts”, in the same manner as in Production Example 1, Dodecyl polyoxyethylene (addition mole number 25 mol) methacrylate {vinyl monomer (b7)} was obtained.

<Production Example 8>
In the same manner as in Production Example 1, except that “ethylene oxide 4210 parts” and “ethylene oxide 4210 parts” were changed to “ethylene oxide 5010 parts and propylene oxide 1320 parts” and “ethylene oxide 5010 parts and propylene oxide 1320 parts”. Oxyethylene (addition mole number 25 mol) polyoxypropylene (addition mole number 5 mol) methacrylate {vinyl monomer (b8)} was obtained.

<Production Example 9>
“Methanol 292 parts”, “ethylene oxide 4210 parts” and “ethylene oxide 4210 parts” were changed to “octanol 1180 parts”, “ethylene oxide 1600 parts” and “ethylene oxide 1600 parts” in the same manner as in Production Example 1, Octyl polyoxyethylene (addition mole number 8 mol) methacrylate {vinyl monomer (r1)} was obtained.

<Production Example 10>
Octadecyl polyoxyethylene (added mole number: 21 mol) methacrylate {vinyl monomer (r2)} was obtained in the same manner as in Production Example 1 except that “292 parts of methanol” was changed to “2460 parts of octdecanol”.

<Production Example 11>
Methyl polyoxyethylene (added mole number 20 mol) methacrylate in the same manner as in Production Example 1 except that “ethylene oxide 4210 parts” and “ethylene oxide 4210 parts” were changed to “ethylene oxide 4010 parts” and “ethylene oxide 4010 parts”. {Vinyl monomer (r3)} was obtained.

<Example 1>
A reaction vessel was charged with 423 parts of water and 228 parts of isopropyl alcohol (hereinafter abbreviated as IPA), purged with nitrogen, heated to 80 ° C., and refluxed at 80 ° C. with stirring (recirculation continued until completion of aging). 56.7 parts of methacrylic acid [80 mol% {"mol%" means the concentration based on the total number of moles of (meth) acrylic acid (salt) (A) and vinyl monomer (B), and so on. . }] And vinyl monomer (b1) 169 parts (20 mol%) mixed with monomer solution (1) and sodium persulfate 5% aqueous solution 94.2 parts (2.4 mol%) added dropwise simultaneously over 3 hours And reacted. Subsequently, after aging at 80 ° C. for 2 hours, IPA was distilled off at 80 ° C. Thereafter, the mixture was cooled to 40 ° C, neutralized by adding 55.5 parts (80 mol%) of a 48% aqueous solution of sodium hydroxide over 10 minutes at 40 ° C, and then cooled to 25 ° C. After measuring the concentration by the following method (hereinafter the same), water was added at 25 ° C. to obtain a copolymer [1] aqueous solution having a concentration of 30%.
The weight average molecular weight {by the following method (hereinafter the same)} of the copolymer [1] was 288,000.

<Measurement method of concentration>
About 2 g of the copolymer aqueous solution was weighed and collected in a glass petri dish. The glass petri dish was heated with a circulating dryer at 130 ° C. for 1 hour, then removed from the circulating dryer and placed in a desiccator, and cooled to 25 ° C. The residue remaining on the glass petri dish was weighed, and the concentration of the aqueous copolymer solution was calculated according to the following formula.

<Weight average molecular weight>
Measuring instrument: Waters GPC system [pump; Model 510,
Detector; waters 410]
Eluent: Type Water / methanol (70/30 (volume ratio)) + sodium acetate {5 g / liter (vs water / methanol)}
Flow rate 1.0 (ml / min)
Column: TSKgel G3000PWXL + TSKGel G50000PWXL
7.8 ml I.V. D x 30cm
Column temperature: 40 ° C
Standard substance: polyethylene glycol {weight average molecular weight: 2.4 × 10 ⁴ , 5.0 × 1
0 ⁴ , 1.07 × 10 ⁵ , 2.5 × 10 ⁵ , 5.4 × 10 ⁵ , 9.0 × 10 ⁵ (TSK standard polyethylene oxide SE-2, SE-5, SE-8 manufactured by Tosoh Corporation) , SE-30, SE-70, SE-150)}

<Examples 2-12 and Comparative Examples 1-3>
“Water 423 parts and isopropyl alcohol 228 parts”, “methacrylic acid 56.7 parts”, “vinyl monomer (b1) 169 parts”, “sodium persulfate 5% aqueous solution 94.2 parts” and “sodium hydroxide 48% aqueous solution” 55.5 parts "described in Table 1," solvent, (meth) acrylic acid (salt) (A), vinyl monomer (B), other vinyl monomer (C), polymerization initiator, alkali (respectively corresponding Except that the amount was changed to "Amount used"), aqueous solutions of copolymers [2] to [12] of Examples 2 to 12 and copolymers [13] of Comparative Examples 1 to 3 in the same manner as Example 1. An aqueous solution of [15] was obtained. Table 1 shows the measurement results of the weight average molecular weight (GPC) of the copolymers [2] to [15].

なお、表１中のａ１〜ａ２及びｃ１〜ｃ３の各記号は次のものを示し、ｂ１〜ｂ８及びｒ１〜ｒ３の各記号は製造例１〜１１で製造した単量体を示す。
ａ１：メタクリル酸
ａ２：アクリル酸
ｃ１：メタクリル酸メチル
ｃ２：メチルポリオキシエチレンメタクリレート（オキシエチレンの数：９）
ｃ３：メタクリル酸ヒドロキシエチル

In addition, each symbol of a1 to a2 and c1 to c3 in Table 1 represents the following, and each symbol of b1 to b8 and r1 to r3 represents the monomer produced in Production Examples 1 to 11.
a1: Methacrylic acid a2: Acrylic acid c1: Methyl methacrylate c2: Methyl polyoxyethylene methacrylate (number of oxyethylenes: 9)
c3: Hydroxyethyl methacrylate

<Example 13>
After dry blending 100 parts of silicon carbide powder (volume average particle size 30 μm) and 5 parts of methylcellulose (“Metroze SHV-P”, manufactured by Shin-Etsu Chemical Co., Ltd.) with an omni-type mixer (25 ° C.), 65 parts of water and examples An aqueous solution obtained by mixing 3.3 parts of the copolymer [1] aqueous solution obtained in 1 was added and kneaded at 25 ° C. to obtain a water kneaded product. The hardness (by the following method) of the water kneaded product was measured.
The kneaded product is extruded at a speed of 5.4 mm / mm at 25 ° C. through a screw type extruder (SY-05S type vacuum extruder manufactured by Ishikawa Tokiko) with a 50 mmφ cylinder and a 10 mmφ die attached to the tip. Extrusion molding was performed at s to obtain an extrusion molded body. At this time, the extrusion load at the time of extrusion molding was continuously measured with a load cell connected to the cylinder of the extruder, and the maximum value is shown in Table 2. Moreover, the surface state (appearance) of the extruded product was observed, and the observation results are shown in Table 2.
The obtained extrudate was cut to a length of 50 mm and heated in an electric furnace at 450 ° C. for 2 hours in a mixed gas atmosphere of air and nitrogen having an oxygen concentration of 5% by volume. Subsequently, the temperature was raised to 2200 ° C. in a nitrogen gas atmosphere and heated at 2200 ° C. for 2 hours, and then cooled to room temperature (about 25 ° C.) to obtain a ceramic molded body. The surface state (appearance) of this ceramic molded body was observed, and the observation results are shown in Table 2.

  Extrusion molding, heat treatment, and the like were performed in the same manner as described above except that “extrusion speed 5.4 mm / s” was changed to “11 mm / s” to obtain extrusion moldings and ceramic moldings. Similarly to the above, the maximum value of the extrusion load at the time of extrusion molding, the surface state of the extrusion molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Hardness of water kneaded material>
About 500 g of the water kneaded product was formed into a rectangular parallelepiped shape having a thickness of about 5 cm using a spatula. Hardness was measured using an NGK hardness meter (manufactured by NGK) with the measuring probe perpendicular to the upper plane of the molded product.
It measured 10 times about a different location with said method, and made this arithmetic average value the hardness of a water kneaded material.

<Example 14>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [2] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Example 15>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [3] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Example 16>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [4] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Example 17>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [5] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Example 18>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [6] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Example 19>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [7] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Example 20>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [8] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Example 21>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [9] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Example 22>
Extruded bodies and ceramic molded bodies were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [10] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Example 23>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [11] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Example 24>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [12] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.
<Comparative example 4>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [13] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Comparative Example 5>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that “Copolymer [1] 3.3 parts” was changed to “Copolymer [14] 3.3 parts”. . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

<Comparative Example 6>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 13, except that "Copolymer [1] 3.3 parts" was changed to "Copolymer [15] 3.3 parts". . Then, in the same manner as in Example 13, the hardness of the water kneaded product, the extrusion load during extrusion molding, the surface state of the extruded molded body, and the surface state of the ceramic molded body are shown in Table 2.

(Note) Surface state of the extrusion molded body ○: The surface of the molded body is smooth ×: The surface of the molded body is scale-like or cracks are generated on the surface Surface state of the ceramic molded body ○: The surface of the molded body is smooth ×: The molded body The surface of the surface is scale-like or cracks are generated on the surface

As shown in Table 2, when the dispersant of the present invention was used (Examples 13 to 24), even when the extrusion speed was increased as compared with Comparative Examples 4 to 6, the {extrusion speed (11 mm / s)} was achieved. The extrusion load was small, and the surface appearance of the molded product was good.
(1) In Examples 13 to 24, even when the extrusion speed was increased (extrusion speed 11 mm / s), the surface finish of the molded product was good. Comparing the results of the extrusion load of the example of the extrusion speed of 11 mm / s and the comparative example, the extrusion load of the example (extrusion load 0.36 to 0.51 MPa) is the extrusion load of the comparative example (extrusion load 0.53 to 0). .70 MPa), the adhesiveness of the composition containing ceramic or the like is reduced, and slippage within the die is improved, so that it is assumed that the extrudability is good.
(2) Extrusion load (extrusion load of 0.36 to 0.51 MPa) applied to the extruder at the extrusion speed of 11 mm / s in Examples 13 to 24 is 5.4 mm / s of Comparative Examples 4 to 6. In this case, the extrusion load (extrusion load 0.40 to 0.48 MPa) is approximately the same. From this result, it is considered that the extrusion speed can be increased with the same level of extrusion load as before, and the amount of molded product produced per unit time will increase.

Claims (3)

In a dispersant used for producing a ceramic molded body by extruding a composition containing ceramic particles, a binder, a dispersant and water, followed by firing.
A vinyl polymer (P) having (meth) acrylic acid (salt) (A) and a vinyl monomer (B) represented by formula (1) as an essential constituent monomer, wherein (meth) acrylic acid (salt) Based on the number of moles of (A) unit and vinyl monomer (B) unit, the content (mol%) of (meth) acrylic acid (salt) (A) unit is 72 to 98, the content of vinyl monomer (B) unit A dispersant for ceramic extrusion, comprising a vinyl polymer (P) in an amount (mol%) of 2 to 28.

{In the formula, R ¹ is a (meth) acryloyl group, O is an oxygen atom, AO is an oxyalkylene group having 2 to 4 carbon atoms, p is an integer of 21 to 200, X is a hydrogen atom or an alkyl having 1 to 12 carbon atoms Represents a group. } The dispersing agent according to claim 1, wherein (meth) acrylic acid (salt) (A) is an alkali metal salt of (meth) acrylic acid.   3. A step of extruding a composition containing the dispersant, ceramic particles, binder and water according to claim 1 or 2 to obtain an extruded product, and a step of firing the extruded product to obtain a fired product. A method for producing a ceramic molded body.