JP5642626B2 - Ceramic kneading composition for ceramic extrusion - Google Patents

Description

  The present invention relates to a dispersant used for a ceramic kneaded composition in a method for producing a ceramic product including a step of extruding a ceramic kneaded composition, a ceramic kneaded composition, an extrusion method for a ceramic kneaded composition, a ceramic product, and The present invention relates to a method for manufacturing a ceramic product.

  Ceramic products are excellent in optical properties, electrical properties, and biocompatibility in addition to heat resistance, wear resistance, and corrosion resistance, and are used in a wide range of fields such as electronics and medical fields. These ceramic products are usually obtained by molding a ceramic kneaded composition containing ceramic particles by extrusion molding, injection molding, cast molding, tape molding, pressure molding, or the like and then firing. Of the above molding methods, extrusion molding is suitable as a molding method for automobile exhaust gas treatment catalyst carriers, black smoke removal filters, insulating pipes, and water purification treatment filters. In the ceramic kneaded composition in extrusion molding, it is necessary to reduce the ratio of water contained as much as possible in order to reduce dimensional changes during firing after extrusion molding and to reduce energy costs required for firing. However, decreasing the water usually increases the viscosity. Therefore, an additive called a dispersant may be added so that the viscosity is lowered even if water is reduced (for example, low molecular weight fatty acid salts disclosed in Patent Document-1 and Patent Document-2). ). However, although the conventional dispersant can certainly reduce the viscosity of the ceramic kneaded composition itself, there is a problem that the lubricity during extrusion is low. In particular, when trying to improve the productivity by increasing the molding speed, there is a problem that the extrusion load becomes large and the surface of the extruded product tends to become rough or cracks even if forced extrusion is possible. It was.

Japanese Patent Laid-Open No. 2-81606 JP 2002-293645 A

  The present invention not only has a dispersion effect of the ceramic kneaded composition, but also has excellent lubricity even when the extrusion speed is increased during extrusion molding, the extrusion load during extrusion molding is small, and the surface of the extruded molded body becomes rough and cracks are generated. An object of the present invention is to provide a ceramic kneaded composition capable of reducing the amount of slag.

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 present invention is a dispersant used for the ceramic kneaded composition in a method for producing a ceramic product including a step of extruding the ceramic kneaded composition, comprising (meth) acrylic acid (salt) (A) and see contains general formula (1) vinyl monomer (B) represented by the constituent monomer units, based on the total number of moles of the (meth) acrylic acid (salt) (a) and the vinyl monomer (B) the (meth) dispersion containing an acrylic acid (salt) (a) a 30 to 98 mole% and the vinyl monomer (B) including a vinyl polymer (P) as a constituent monomer units 2 to 70 mol% A ceramic kneading composition comprising an agent, ceramic particles, a cellulose derivative, and water , wherein 60 to 90% by weight of ceramic particles are based on the weight of the ceramic kneading composition A ceramic kneading composition containing 2 to 20% by weight of a cellulose derivative, 0.05 to 10% by weight of a dispersant, and 5 to 37.5% by weight of water .
R ¹ —O— (AO) pX (1)
{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 a number from 1 to 200, X is a hydrogen atom or an alkyl having 1 to 18 carbon atoms Represents a group. }

  Based on the total number of moles of the (meth) acrylic acid (salt) (A) and the vinyl monomer (B), the vinyl polymer (P) has 30 to 30 parts of the (meth) acrylic acid (salt) (A). It is preferable to contain 98 mol% and 2 to 70 mol% of the vinyl monomer (B) as constituent monomer units. The (meth) acrylic acid (salt) (A) is preferably at least one selected from the group consisting of (meth) acrylic acid ammonium salts and (meth) acrylic acid organic amine salts.

  The ceramic kneaded composition comprises 60 to 90 wt% ceramic particles, 2 to 20 wt% binder, 0.05 to 10 wt% dispersant and 5 to 37.5 based on the weight of the ceramic kneaded composition. It is preferable to contain water by weight.

  The present invention also relates to a method for extruding a ceramic kneaded composition, characterized by using the above dispersant. The extrusion speed of the ceramic kneaded composition is preferably 2 to 50 mm / s.

  Moreover, this invention relates to the ceramic product obtained by the manufacturing method of the ceramic product including the process of obtaining an extrusion molding body by said extrusion molding method, and the process of baking the said extrusion molding body, and said manufacturing method.

  In the ceramic kneaded composition of the present invention, since a vinyl polymer having a specific structure is used as a dispersant, not only the dispersibility of the ceramic kneaded composition is good, but also the lubricity during extrusion molding is excellent. Even if the speed is increased, the extrusion load is small, and the surface roughness of the extruded product and the generation of cracks can be reduced. Moreover, the ceramic product excellent in the surface state can be obtained even after firing.

The dispersant in the present invention contains a vinyl polymer (P). The vinyl polymer (P) contains (meth) acrylic acid (salt) (A) and a vinyl monomer (B) represented by the general formula (1) as constituent monomer units. In the present invention, "(meth) acryl ..." means "acryl ..." and / or "methacryl ...", and "... acid (salt)" means "... -"Acid" and / or "... acid salt". “Containing as a constituent monomer unit” means that a substituted alkylene group derived from a monomer (in this case (meth)) acrylic acid (salt) (A) and vinyl monomer (B)) is a vinyl polymer. It is meant to be included as a structural unit of (P).
Examples of the (meth) acrylic acid (salt) (A) include methacrylic acid, acrylic acid, and salts thereof. Examples of (meth) acrylates include alkali metal salts (sodium salt and potassium salt, etc.), alkaline earth metal salts (calcium salt, magnesium salt, etc.), ammonium salts [ammonium salts, tetraalkyls (1 to 8 carbon atoms). Ammonium salt (tetramethylammonium salt etc.)], organic amine salt [alkylamine salt having 1 to 8 carbon atoms, 2 to 2 carbon atoms]
8 alkanolamine salts, polyalkylene (1 to 8 carbon atoms) polyamine salts (2 to 10 amino groups) and polyalkylene polyamine derivative salts {derivatives alkylated with alkyl groups having 1 to 8 carbon atoms and 2 carbon atoms To 12 alkylene oxide adducts (average number of moles added per amino group 1 to 30 moles)} and the like. Among (A), from the viewpoint of lubricity during extrusion, (meth) acrylic acid in which a salt is formed with a nitrogen atom-containing compound of (meth) acrylic acid and (meth) acrylate is preferable. And (meth) acrylic acid organic amine salts, particularly preferably (meth) acrylic acid alkanolamine salts, most preferably (meth) acrylic acid triethanolamine salts and (meth). Acrylic acid diethanolamine salt.

In the general formula (1) representing the vinyl monomer (B), R ¹ is preferably a methacryloyl group from the viewpoint of lubricity during extrusion molding. Examples of AO include an oxyethylene group, an oxypropylene group, and an oxybutylene group. Of AO, from the viewpoint of lubricity during extrusion, an oxyethylene group and an oxypropylene group are preferred, and an oxyethylene group is more preferred. (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 a number of 1 to 200, preferably from 11 to 190, more preferably from 13 to 180, and particularly preferably from 21 to 150, from the viewpoint of lubricity during extrusion molding. When p is 21 to 150, the effect of further improving the shape retention during extrusion can be exhibited. In addition, the part of (AO) p in the general formula (1) is usually an alkylene oxide adduct, and the vinyl monomer (B) is a mixture containing compounds having different addition mole numbers in a certain distribution, p Represents the average number of moles added and is not necessarily an integer.

  Among X, as the alkyl group having 1 to 18 carbon atoms, a linear alkyl group (methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl, n-decyl, n-undecyl, n- Dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl and n-octadecyl groups) and branched alkyl (isopropyl, t-butyl, isopentyl, 2-ethylhexyl, isodecyl and isododecyl groups, etc.) Is mentioned. Of these, from the viewpoint of lubricity during extrusion, a linear alkyl group is preferable, and methyl, ethyl, n-propyl, n-butyl, n-hexyl and n-octyl groups are more preferable. X is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, rather than a hydrogen atom from the viewpoint of lubricity and shape retention during extrusion molding.

Examples of the vinyl monomer (B) include hydroxyalkyl (meth) acrylate, polyalkylene glycol mono (meth) acrylate, and alkoxy (poly) alkylene glycol mono (meth) acrylate. Here, (poly) of alkoxy (poly) alkylene glycol mono (meth) acrylate is applied when the number of repeating units of oxyalkylene is 2 or more.

  Examples of the hydroxyalkyl (meth) acrylate include 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate. Examples of the polyalkylene glycol mono (meth) acrylate include polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, and polybutylene glycol mono (meth) acrylate. As alkoxy (poly) alkylene glycol mono (meth) acrylate, methoxy (poly) ethylene glycol mono (meth) acrylate, hexyloxy (poly) ethylene glycol mono (meth) acrylate, octoxy (poly) ethylene glycol mono (meth) acrylate, Examples include lauroxy (poly) ethylene glycol mono (meth) acrylate and octadecyloxy (poly) ethylene glycol mono (meth) acrylate. As the vinyl monomer (B), a vinyl monomer described in JP-A-2005-289844 can also be used. These vinyl monomers (B) may be used alone or in combination of two or more.

  Of the vinyl monomers (B), alkoxy (poly) alkylene glycol mono (meth) acrylate is preferable from the viewpoint of extrusion moldability, and more preferably alkoxy (poly) alkylene glycol (2 to 3 carbon atoms) mono (meth) acrylate. Then, more preferably alkoxy (C1-6) (poly) alkylene (C2-3) glycol mono (meth) acrylate, particularly preferably alkoxy (C1-6) (poly) ethylene glycol mono (Meth) acrylate, most preferably alkoxy (C1-6) (poly) ethylene glycol monomethacrylate.

  The vinyl monomer (B) can be produced by a known production method (for example, JP-A-2005-289844), but a commercially available product may be used. Known production methods include a method in which (meth) acrylic acid and (poly) oxyalkylene compound are esterified in the presence of an acid catalyst, or a (meth) acrylic acid ester and (poly) oxyalkylene compound in a basic catalyst. And a method of carrying out an ester exchange reaction in the presence of, or a method of adding an alkylene oxide to (meth) acrylic acid. Commercially available products include “Blemmer (registered trademark) PME series” [“Blemmer PME-1000” (methoxypolyethylene glycol monomethacrylate: general formula (1), AO = oxyethylene, p = 23, X = Methyl) and “Blemmer PME-4000” (methoxypolyethylene glycol monomethacrylate: AO = oxyethylene, p = 90, X = methyl, etc. in the general formula (1), etc.)] and “Light Ester 041MA” manufactured by Kyoeisha Chemical Co., Ltd. (Methoxypolyethylene glycol monomethacrylate: In general formula (1), AO = oxyethylene, p = 30, X = methyl) and the like.

  The content of the (meth) acrylic acid (salt) (A) unit in the vinyl polymer (P) is the total number of moles (100 mol%) of the (A) unit and the (B) unit from the viewpoint of lubricity during extrusion molding. Is preferably 30 to 98 mol%, more preferably 32 to 97 mol%, then still more preferably 34 to 96 mol%, particularly preferably 36 to 95 mol%. If the amount is less than 30 mol%, the dispersibility tends to decrease, and if it exceeds 98 mol%, the lubricity tends to decrease.

  The content of the vinyl monomer (B) unit in the vinyl polymer (P) is 2 based on the total number of moles (100 mol%) of the (A) unit and the (B) unit from the viewpoint of lubricity during extrusion molding. -70 mol% is preferable, More preferably, it is 3-68 mol%, Next, More preferably, it is 4-66 mol%, Most preferably, it is 5-64 mol%.

  The vinyl polymer (P) may contain, in addition to (A) and (B), another vinyl monomer (C) [hereinafter sometimes simply referred to as (C)] as a constituent monomer unit. Good. (C) is not particularly limited as long as it is a monomer copolymerizable with (A) and (B).

  (C) includes (meth) acrylamide and its derivatives [(meth) acrylamide and N, N′-dimethyl (meth) acrylamide etc.]; alkyl (meth) acrylate and its derivatives [methyl (meth) acrylate, 2-ethylhexyl (Meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, etc.]; Cationic (meth) acrylate [dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and quaternized products thereof, etc.]; (Meth) acryloyloxyalkyl sulfonate [2- (meth) acryloyloxyethyl sulfonate and 3- (meth) acryloyloxypropyl sulfonate, etc.]: and (meth) allyl sulfonate; A monomer according to -154,266 JP also be mentioned.

  Among (C), alkyl (meth) acrylate and cationic (meth) acrylate are preferable from the viewpoint of lubricity during extrusion molding, and alkyl (meth) acrylate is more preferable.

  When other vinyl monomer (C) is used as a constituent monomer unit, the content of (C) unit is (A) unit, (B) unit and (C) unit from the viewpoint of lubricity during extrusion molding. Based on the total number of moles (100 mole%) of 0 to 10 mole%, preferably 0 to 9 mole%, more preferably 0 to 8 mole%, particularly preferably 0 to 6 mole%. is there. When it exceeds 10 mol%, the dispersibility tends to decrease.

  The weight average molecular weight (hereinafter abbreviated as Mw) of the vinyl polymer (P) is preferably 10,000 to 1,800,000, more preferably 20,000 to 1, from the viewpoint of lubricity during extrusion molding. 1,000,000, particularly preferably 30,000 to 800,000. Mw is measured by gel permeation chromatography (GPC) method (standard substance: polyethylene glycol). Among these, those having a low Mw (30,000 to 200,000) are preferred because dispersibility tends to be improved. Further, those having a high Mw (200,000 to 800,000) are preferred because the lubricity tends to be improved.

  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 the vinyl polymer (P) is a salt, the vinyl polymer (P) may be produced using (meth) acrylate, or after obtaining the vinyl polymer using (meth) acrylic acid, It is good also as a salt by neutralizing with the alkaline compound which forms (for example, Unexamined-Japanese-Patent No. 2001-152199). Of these methods, the latter is preferable from the viewpoint of easy adjustment of Mw. In the latter case, while cooling the reaction mixture, it is possible to neutralize by adding and mixing necessary alkaline compounds so that the pH at 25 ° C. is 5.5 to 8.5 (25 ° C.). it can.

  The dispersant in the present invention may contain a known binder. Examples of the binder include cellulose derivatives (such as methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxyethyl methyl cellulose, and hydroxypropyl methyl cellulose) and synthetic polymers (such as polyethylene oxide, polyacrylamide, and polyvinyl alcohol). As the binder, those described in JP-A No. 2004-203705 and JP-A No. 2002-37673 can also be used. A synthetic polymer is preferable as the binder contained in the dispersant.

  The dispersant in the present invention may contain a known dispersant. Known dispersants include fatty acids or salts thereof (stearic acid, lauric acid, stearates, laurates, etc .; salts include alkali metal salts, ammonium salts, organic amine salts, etc.), polycarboxylic acids (methacrylic acid, Polymers obtained by polymerizing monomers containing unsaturated carboxylic acids such as acrylic acid or maleic anhydride, or salts thereof; as salts, alkali metal salts, ammonium salts, organic amine salts, etc.), and as surfactants Examples include known alkylene oxide adducts of various alcohols. As other known dispersants, those described in JP-A-2004-203705 and JP-A-2002-37673 can also be used.

  The dispersant in the present invention may contain a solvent. Examples of the solvent include water, a hydrophilic solvent, or a combination thereof. Examples of hydrophilic solvents include lower alcohols (such as methanol, ethanol, and isopropanol), glycols (such as ethylene glycol, diethylene glycol, and propylene glycol), trivalent to hexavalent polyhydric alcohols (such as glycerin), and ketones (acetone and methyl ethyl ketone). Etc.), acetonitrile, ethyl acetate and the like. Among the solvents, water and a combination of water and a lower alcohol are preferable from the viewpoint of affinity with the vinyl polymer (P).

  The content of each component in the dispersant in the present invention is preferably from 30 to 95%, more preferably from 40 to 90%, for the vinyl polymer (P), from the viewpoints of lubricity and shape retention during extrusion. Particularly preferred is 50 to 85%; the known binder is preferably 0 to 25%, more preferably 0 to 20%, particularly preferably 0 to 15%; the known dispersant is preferably 0 to 25%. 30%, more preferably 0-25%, particularly preferably 0-20%; the solvent is preferably 5-70%, more preferably 10-60%, particularly preferably 15-50%.

  The dispersant in the present invention can be obtained by mixing the vinyl polymer (P) and other components as necessary at normal temperature or as necessary (80 ° C. or lower).

  The ceramic kneading composition of the present invention is a ceramic kneading composition characterized in that it contains ceramic particles, a binder, a dispersant and water, and the dispersant is a dispersant containing the vinyl polymer (P). is there.

  The ceramic particles include oxide ceramics such as alumina, cordierite, mullite, silica, zirconia, and titania, and non-oxide ceramics such as silicon carbide, silicon nitride, aluminum nitride, boron nitride, titanium nitride, and titanium carbide. Can be mentioned.

  As a binder contained in a ceramic kneading composition, the thing of the composition similar to the binder illustrated as a binder which may be contained in the above-mentioned dispersing agent is mentioned. Among these, the cellulose derivative and the synthetic polymer are preferable.

  The preferable content of each component in the ceramic kneaded composition is 60 to 90% ceramic particles, 2 to 20% binder, 0.05 to 10% dispersant, and water based on the weight of the ceramic kneaded composition. Is 5 to 37.5%. In addition, when the binder already contains the binder, the content including the binder is preferably within the above range. The preferable content of each component is 65 to 85% for ceramic particles, 2 to 10% for the binder, 0.1 to 5% for the dispersant, and 7 to 32.9% for water.

  In addition, although the usage-amount of the dispersing agent in this invention can be variously changed with the kind of ceramic particle | grains, the extrusion speed of extrusion molding, a die shape, etc., from a viewpoint of extrusion moldability, with respect to 100 weight part of ceramic particles. 0.05 to 11 parts by weight, more preferably 0.2 to 5 parts by weight.

  The method for producing the ceramic kneaded composition is not particularly limited, but generally, the ceramic particles and the binder are first dry-mixed, then water and a dispersant are added and wet-mixed, and the mixture thus prepared is A ceramic kneaded composition can be obtained by kneading using a kneader such as a kneader, three rolls or a vacuum kneader. The kneading temperature is preferably 5 to 45 ° C. If it is lower than 5 ° C, the workability during kneading may be reduced, and if it exceeds 45 ° C, the dispersibility may be reduced. The hardness of the ceramic kneaded composition of the present invention is softer than the hardness of a ceramic kneaded composition using a conventional dispersant. The hardness of the ceramic kneaded composition can be measured with a commercially available hardness meter or the like.

The method for extruding a ceramic kneaded composition of the present invention is a method for extruding a ceramic kneaded composition characterized in that the dispersant is used. For extrusion molding, an extruder is usually used. Examples of the extrusion molding machine include a vacuum extrusion molding machine. Examples of the shape of the extruded product include a honeycomb, a pipe, a hollow flat plate, and a sheet. The extrusion speed is usually 2 to 50 mm / s, preferably 5 to 20 mm / s. If it is less than 2 mm / s, the production efficiency tends to decrease, and if it is more than 50 mm / s, the specific gravity of the extruded product tends to become unstable.
The extrusion temperature is preferably 5 to 45 ° C. If it exceeds 45 ° C, the lubricity may decrease. According to the extrusion molding method of the present invention, since the extrusion speed can be made faster than the conventional one (the extrusion speed when the dispersant of the present invention is not used is 2 to 8 mm / s), the productivity can be improved. Is possible. Moreover, the surface state of the extrusion molded body obtained by the extrusion molding method of the present invention is smoother than the conventional method. This is because the dispersant of the present invention is excellent in lubricity.

  The method for producing a ceramic product of the present invention includes a step of obtaining an extruded product by the extrusion method of the present invention and a step of firing the extruded product. Specifically, after cutting the extrusion-molded body to a predetermined length, it is dehydrated by irradiating with hot air, microwaves, or the like to dehydrate the extruded-molded body, and degreased organic substances such as a binder and a dispersant. There is a method of obtaining a ceramic product by firing. The temperature of hot air is usually 80 to 150 ° C., and the temperature for degreasing and baking is usually 500 to 1500 ° C. Detailed manufacturing conditions are disclosed in, for example, JP-A-2002-37673. In addition, the step of obtaining the ceramic product includes a cooling operation after firing, and may further include a step of machining the obtained fired body if necessary.

  The ceramic product of the present invention is a ceramic product obtained by the above manufacturing method, and has a smoother surface than conventional ceramic products.

<Example>
Hereinafter, the present invention will be further described with reference to production examples and examples, but the present invention is not limited thereto. In the following, “parts” and “%” represent “parts by weight” and “% by weight” unless otherwise specified.

Production example of vinyl monomer (B):
<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. After 4210 parts of ethylene oxide were blown and reacted at 100 ° C. over 1 hour, the temperature was raised to 180 ° C., and 4210 parts of ethylene oxide was further blown and reacted at 180 ° C. over 1 hour. Thereafter, the mixture was aged at 180 ° C. for 1 hour and then 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 obtained the methoxypolyethyleneglycol (21 addition mole number) monomethacrylate {vinyl monomer (B1)}.

<Production Example 2>
Except that “methanol 292 parts”, “ethylene oxide 4210 parts” and “ethylene oxide 4210 parts” were changed to “butanol 637 parts”, “ethylene oxide 12045 parts” and “ethylene oxide 28105 parts”, in the same manner as in Production Example 1, Butoxypolyethylene glycol (addition mole number 100 mol) monomethacrylate {vinyl monomer (B2)} was obtained.

<Production Example 3>
“Methanol 292 parts”, “ethylene oxide 4210 parts”, “ethylene oxide 4210 parts” and “methacrylic acid 1960 parts” were replaced with “decanol 1347 parts”, “ethylene oxide 6010 parts”, “ethylene oxide 6010 parts” and “acrylic acid 1640 parts”. In the same manner as in Production Example 1, except that it was changed to decyloxypolyethylene glycol (addition mole number 30 mol) monoacrylate {vinyl monomer (B3)} was obtained.

<Production Example 4>
Methoxypolyethylene glycol (added mole number 200 mol) monomethacrylate 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 (B4)} was obtained.

<Production Example 5>
Except that “methanol 292 parts”, “ethylene oxide 4210 parts” and “ethylene oxide 4210 parts” were changed to “dodecanol 1583 parts”, “ethylene oxide 5010 parts” and “ethylene oxide 5010 parts”, in the same manner as in Production Example 1, Dodecyloxypolyethylene glycol (addition mole number 25 mol) monomethacrylate {vinyl monomer (B5)} was obtained.

<Production Example 6>
Methoxypolyethylene glycol (addition mole number 13 mol) monomethacrylate 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 2008 parts” and “ethylene oxide 3212 parts”. {Vinyl monomer (B6)} was obtained.

<Production Example 7>
Methoxypolyethylene glycol (addition mole number 10 mol) monomethacrylate 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 4015 parts” and “ethylene oxide 0 parts”. {Vinyl monomer (B7)} was obtained.

<Production Example 8>
Methoxypolyethylene glycol (8 moles added) monomethacrylate 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 1600 parts” and “ethylene oxide 1600 parts”. {Vinyl monomer (B8)} was obtained.
<Production Example 9>
“Methanol 292 parts”, “ethylene oxide 4210 parts” and “ethylene oxide 4210 parts” were changed to “octadecanol 2293 parts”, “ethylene oxide 40050 parts” and “ethylene oxide 34034 parts” in the same manner as in Production Example 1. Thus, octadecyloxypolyethylene glycol (addition mole number 185 mol) monomethacrylate {vinyl monomer (B9)} was obtained.
<Production Example 10>
“Methanol 292 parts”, “ethylene oxide 4210 parts” and “ethylene oxide 4210 parts” were changed to “propanol 519 parts”, “ethylene oxide 1205 parts” and “ethylene oxide 0 parts” in the same manner as in Production Example 1, Propoxy polyethylene glycol (addition mole number 3 mol) monomethacrylate {vinyl monomer (B10)} was obtained.

Examples of dispersants and comparative examples:
(A) Methacrylic acid or acrylic acid is used, and vinyl monomers (B1) to (B10) or hydroxyethyl methacrylate (B11) obtained in the above production examples are used as vinyl monomers (B). Polymerization was performed using methyl methacrylate (C1) or ethyl acrylate (C2) as the monomer (C). These were made into the dispersing agent of Examples 1-17 and Comparative Examples 1-2. In Examples 1 to 3, 5 to 7, 8, 9, and 11 to 17, a neutralizing agent was added after polymerization to form a salt to produce an aqueous vinyl polymer solution. Details are as follows.

<Example 1>
A reaction vessel was charged with 425 parts of water and 225 parts of isopropyl alcohol (hereinafter abbreviated as IPA), purged with nitrogen, heated to 82 ° C., and refluxed with stirring (recirculation continued until completion of aging). 62.8 parts [80 mol% {"mol%" means the content based on the total number of moles of (A) and (B), and so on. }] And vinyl monomer (B1) 187.2 parts (20 mol%) mixed with 100.0 parts of a 5% aqueous solution of sodium persulfate as a polymerization initiator simultaneously over 3 hours for polymerization. Reacted. Subsequently, after aging at 82 ° C. for 2 hours, IPA was distilled off at 82 ° C. Thereafter, the mixture was cooled to 40 ° C., and neutralized by adding 87.0 parts (80 mol%) of triethanolamine as a neutralizing agent at 40 ° C. over 10 minutes, and then cooled to 25 ° C. After measuring the density | concentration of vinyl polymer aqueous solution with the following method, water was added and water content was adjusted and the dispersing agent [D1] which consists of vinyl polymer [P1] 30% and water 70% was obtained. Mw (by the following method) of the vinyl polymer [P1] was 290,000.

<Measurement method of vinyl polymer content in aqueous vinyl polymer solution>
About 2 g of an aqueous vinyl polymer solution was collected in a glass petri dish and accurately weighed. The glass petri dish was heated for 1 hour in a circulating dryer at 105 ° C., then removed from the circulating dryer, placed in a desiccator, and cooled to 25 ° C. The percentage (%) of the weight of the residue remaining on the glass petri dish with respect to the weight of the collected aqueous vinyl polymer solution was calculated and used as the vinyl polymer content (%).

<Measurement method of Mw>
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 and TSKgel G50000PWXL
7.8 ml I.V. D x 30cm
Column temperature: 40 ° C
Standard substance: Polyethylene glycol {Mw: 2.4 × 10 ⁴ , 5.0 × 10 ⁴ , 1.07 × 10 ⁵ , 2.5 × 10 ⁵ , 5.4 × 10 ⁵ , 9.0 × 10 ⁵ ( Tosoh Corporation TSK standard polyethylene oxide SE-2, SE-5, SE-8, SE-30, SE-70, SE-150)}

<Examples 2-17 and Comparative Examples 1-2>
“Water 425 parts and isopropyl alcohol 225 parts”, “methacrylic acid 62.8 parts”, “vinyl monomer (b1) 187.2 parts”, “sodium persulfate 5% aqueous solution 100.0 parts” and “triethanolamine 87” .0 part "in" Solvent, "Methacrylic acid", "Acrylic acid", (B), (C), Polymerization initiator, Neutralizing agent (respectively corresponding to Table 1, 2 or 3) Except that it was changed to “Amount used”), the dispersants [D2] to [D17] of Examples 2 to 17 and the dispersants [X1] to [X2] of Comparative Examples 1 to 2 were the same as in Example 1. Got. Tables 1 to 3 show the measurement results of Mw of vinyl polymers [P2] to [P19] contained in these dispersants. In the table, SPS represents a 5% aqueous solution of sodium persulfate, TEA represents triethanolamine, and NH4 represents a 28% aqueous solution of ammonia.

<Comparative Examples 3-5>
As the dispersants of Comparative Examples 3 to 5, the following commercially available products [X3] to [X5] were used.
[X3]: Sodium stearate [X4]: Oleic acid [X5]: Nonionic activator “New Pole 50HB-400” (manufactured by Sanyo Chemical Industries, Ltd., ethylene oxide / propylene oxide adduct of linear alcohol)

<Examples 18 to 34 and Comparative Examples 6 to 10>
Using the dispersant, ceramic kneaded compositions of Examples 18 to 34 and Comparative Examples 6 to 10 were produced as follows. After dry blending 100 parts of silicon carbide powder (volume average particle size 30 μm) as ceramic particles and 5 parts of methyl cellulose (“Metroise 90SH-30000”, manufactured by Shin-Etsu Chemical Co., Ltd.) as a binder with a high shear mixer (25 ° C.) , 16.0 parts of water and 3.3 parts of the dispersant [D1] to [D17] or [X1] to [X2] (or 1.0 part of the dispersant [X3] to [X5]) The mixture was kneaded at 25 ° C. with a kneader to obtain a ceramic kneaded composition.

<Evaluation of ceramic kneaded composition>
(1) Extrusion load at the time of extrusion molding The ceramic kneaded composition is packed into a 12 mmφ piston with a 7.5 mmφ mouthpiece at the end of the cylinder, and the piston is pushed at an extrusion speed of 5.0 mm / s or 10.0 mm / s. The extruded product was obtained by taking out. At this time, the load applied to the piston was measured, and the maximum value was shown in Table 4 as “extrusion load during extrusion (MPa)”.
(2) Hardness of the ceramic kneaded composition The ceramic kneaded composition remaining in the piston when the extrusion test was performed at an extrusion speed of 10.0 mm / s was taken out, and the measurement probe was perpendicular to the surface, Hardness was measured using an NGK hardness tester (manufactured by NGK). It measured 10 times about different places with said method, and made this arithmetic average value the hardness of a ceramic kneading composition. The results are shown in Table 4.
(3) Surface state of extruded molded body The surface state of the extruded molded body obtained in the above (1) was visually observed and evaluated according to the following evaluation criteria. The results are shown in Table 4.
◎: Surface is smooth ○: Part of the surface is not smooth △: Part of the surface is not smooth and part is cracked ×: The surface is not smooth (4) Surface condition of the ceramic product. The extruded product obtained in the above (1) was cut into a length of 50 mm, heated and fired in an electric furnace at 1200 ° C. for 5 hours, It cooled to room temperature (about 25 degreeC), the surface state of the obtained ceramic product was observed visually, and it evaluated by the same evaluation criteria as said (3). The results are shown in Table 4.

  As shown in Table 4, when the dispersant of the present invention was used, the extrusion load was small, and the surface appearance of the extruded product and the ceramic product was good. The effect of the dispersant of the present invention is presumed that the adhesiveness of the composition containing ceramic or the like is lowered and the slip in the die is improved, so that the lubricity is good.

  The dispersant in the present invention can be suitably used as a dispersant for ceramic extrusion.

Claims (6)

A dispersant used for a ceramic kneaded composition in a method for producing a ceramic product including a step of extruding a ceramic kneaded composition, comprising (meth) acrylic acid (salt) (A) and general formula (1) look containing a vinyl monomer (B) expressed as constituent monomer units, based on the total number of moles of the (meth) acrylic acid (salt) (a) and the vinyl monomer (B), the (meth) acrylic dispersing agents, ceramic particles containing acid (salt) (a) a 30 to 98 mole% and the vinyl monomer (B) including a vinyl polymer as a constituent monomer units 2 to 70 mol% (P), cellulose a ceramic kneaded composition characterized by containing the derivative and water, based on the weight of the ceramic kneading composition, 60 to 90 wt% of the ceramic particles, 2 to 20 wt% Se Loin derivatives, ceramic kneaded composition containing 0.05 to 10% by weight of dispersant and from 5 to 37.5% by weight of water.
R ¹ —O— (AO) pX (1)
{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 a number from 1 to 200, X is a hydrogen atom or an alkyl having 1 to 18 carbon atoms Represents a group. } The (meth) acrylic acid (salt) (A) is (meth) ammonium acrylate and (meth) ceramic kneading composition of claim 1 Symbol placement is at least one selected from the group consisting of acrylic acid organic amine salt object. A method for extruding the ceramic kneaded composition according to claim 1 or 2 .   The extrusion molding method according to claim 3, wherein an extrusion speed of the ceramic kneaded composition is 2 to 50 mm / s. Obtaining a claim 3 or 4 extrudates by extrusion method described method for producing a ceramic product comprising the step of firing the extrudate. A ceramic product obtained by the production method according to claim 5 .