JP2008163168A - Lubricant for ceramic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant for ceramic materials, capable of suppressing a rise in a discharge pressure during molding and excellent in lubricating performance. <P>SOLUTION: The lubricant comprises a polyether (A) prepared by the addition reaction of water or a mono- to hexahydric alcohol with tetrahydrofuran and a 2-4C 1,2-alkylene oxide. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lubricant used when producing a ceramic molded body.

  In recent years, honeycomb-structured ceramic extrusions have been used in exhaust gas purification apparatuses such as diesel engines. For exhaust gas purification devices, there is a demand for further thinning of the honeycomb partition walls for the purpose of improving catalyst efficiency, but on the other hand, since thinning tends to cause problems in the formability of extrusion molding, Improvement of the moldability of the clay composition with an ionic polyether lubricant (polyethylene glycol, polyethylene glycol monoalkyl ether, polyethylene polypropylene alkyl ether, etc.) has been proposed (see Patent Documents 1 to 5).

Japanese Patent Laid-Open No. 1-294584 Japanese Patent Laid-Open No. 3-197350 JP-A-6-92715 JP 7-290430 A JP-A-11-58335

  However, the conventionally proposed nonionic polyether lubricants have insufficient lubrication performance, so that the discharge pressure at the die is significantly increased, and there is a limit to the improvement in production speed. Then, an object of this invention is to provide the lubricant for ceramic materials which can suppress the discharge pressure raise at the time of shaping | molding, and is excellent in lubrication performance.

As a result of intensive studies to solve the above problems, the present inventor has reached the present invention.
That is, the present invention is a lubricant for a ceramic material comprising a polyether (A) obtained by adding tetrahydrofuran and a 1,2-alkylene oxide having 2 to 4 carbon atoms to water or 1 to 6-valent alcohol.

  The lubricant for ceramics of the present invention is excellent in lubrication performance between the ceramic particles and between the clay composition and the metal surface of the extrusion molding machine, and therefore suppresses an increase in discharge pressure at the metal mouth during the production of the ceramic molded body. Production speed can be improved.

  Examples of water include tap water, industrial water, ground water, distilled water, ion exchange water, and ultrapure water.

  Examples of the 1-6 valent alcohol compounds include monovalent alcohols (methanol, ethanol, butanol, octanol, etc.); divalent alcohols (ethylene glycol, propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, 3-methylpentanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, neopentyl glycol, 1,4- Bis (hydroxymethyl) cyclohexane, 1,4-bis (hydroxyethyl) benzene, 2,2-bis (4,4′-hydroxycyclohexyl) propane, etc.); trivalent alcohols (glycerin, trimethylolpropane, etc.); To hexavalent alcohol (pentaerythritol, diglycerol, alpha-methyl glucoside, sorbitol, xylitol, mannitol, dipentaerythritol, etc.) and the like; and mixtures of two or more thereof.

  Among these, from the viewpoint of workability of the lubricant, monohydric alcohol and dihydric alcohol with low viscosity are preferable, and methanol, butanol, ethylene glycol, propylene glycol, 1,6-hexanediol, 2 Methyl-2,4-pentanediol, 1,4-butanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, particularly preferably methanol, butanol, ethylene glycol, propylene glycol, 1,6-hexanediol, 2-methyl -2,4-pentanediol, 1,4-butanediol, and diethylene glycol.

  Tetrahydrofuran (hereinafter abbreviated as THF) may be substituted with an alkyl group having 1 to 4 carbon atoms, but is preferably unsubstituted tetrahydrofuran from the viewpoint of lubricity.

  1,2-alkylene oxide (hereinafter abbreviated as AO) is a C2-C4 1,2-alkylene oxide such as ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO). 1,2-butylene oxide (hereinafter abbreviated as BO), isobutylene oxide and halo-substituted products thereof (such as epichlorohydrin). Among these, from the viewpoint of lubricity, EO, PO and BO are preferable, and EO and PO are particularly preferable. AO may use only 1 type and may use 2 or more types of AO together.

  In the polyether (A), the copolymerization mode of THF and AO is not particularly limited, and any of block and random may be used, and from the viewpoint of the workability of the lubricant, the melting point is preferably random.

  The ratio of THF and AO is not particularly limited, but from the viewpoint of lubricity, THF is preferably 20 to 80 mol%, more preferably THF is 30 to 70 mol%, especially based on the total number of moles of THF and AO. Preferably, THF is 40 to 60 mol%. When the ratio of THF and AO is within this range, the lubricity tends to be excellent.

  The number average molecular weight (hereinafter abbreviated as Mn) of the polyether (A) is preferably 300 to 20,000, more preferably 800 to 10,000, particularly preferably from the viewpoint of the viscosity of the clay composition. Is 1,000 to 5,000. Mn can be measured by a gel permeation chromatography method (GPC method, standard substance: polyethylene glycol).

  Specific examples of the polyether (A) include, for example, methanol-THF-EO copolymer, methanol-THF-PO copolymer, methanol-THF-BO copolymer, ethanol-THF-EO copolymer, ethanol -THF-PO copolymer, ethanol-THF-BO copolymer, butanol-THF-EO copolymer, octanol-THF-EO copolymer, ethylene glycol-THF-EO copolymer, ethylene glycol-THF -PO copolymer, ethylene glycol-THF-BO copolymer, propylene glycol-THF-EO copolymer, 1,4-butanediol-THF-EO copolymer, 1,6-hexanediol-THF-EO Copolymer, glycerin-THF-EO copolymer, trimethylolpropane-THF-EO copolymer, Taerythritol-THF-EO copolymer, sorbitol-THF-EO copolymer, dipentaerythritol-THF-EO copolymer, sucrose-THF-EO copolymer, phenol-THF-EO copolymer, hydroquinone -THF-EO copolymer, bisphenol A-THF-EO copolymer, etc. are mentioned.

  The polyether (A) can be produced by a known method (Japanese Patent Application Laid-Open No. 2004-182970, etc.). For example, THF and AO are mixed with 1 to 6 valent alcohol, boron, aluminum, tin, antimony, iron, After ring-opening copolymerization in the presence of an acidic catalyst containing one or more elements selected from the group consisting of phosphorus, zinc, titanium, zirconium and beryllium, alkali metal hydroxide and / or alkaline earth metal hydroxide And then mixed and contacted with at least one adsorbent selected from the group consisting of synthetic silicate, hydrotalcite, magnesium aluminum oxide, activated clay, activated carbon, activated alumina, synthetic zeolite, and ion exchange resin. Thereafter, a production method for filtering the adsorbent is mentioned.

  The polyether (A) can be used as a lubricant for a ceramic material in combination with another polyalkylene polyol (B) not containing tetrahydrofuran. In this case, the content (% by weight) of the polyether (A) in the lubricant is preferably 20 to 100, more preferably 40 to 100, and particularly preferably 60 to 100 from the viewpoint of moldability of the clay composition. It is.

  Other polyalkylene polyols (B) include diethylene glycol, triethylene glycol, polyethylene glycol, di-1,2-propylene glycol, polypropylene glycol having a polymerization degree of 1 to 100 per active hydrogen, polyethylene oxide / polypropylene oxide random, Examples thereof include conventional polyalkylene polyols such as a block or a combination thereof (JP-A-7-69711, JP-A-11-58335, etc.) and the like. Of these, polyethylene oxide / polypropylene oxide copolymers are preferred.

  The other polyalkylene polyol (B) preferably has a Mn of 1,000 to 30,000, more preferably 2,000 to 20,000, from the viewpoint of the viscosity of the clay composition.

When other polyalkylene polyol (B) is used in combination, the compatibility between (A) and (B) is poor, or the viscosity or melting point of the lubricant is adjusted to a value that is easy to use. Methanol, ethanol, butanol, octanol, glycerin, ethylene glycol, propylene glycol and their fatty acid esters and water can be added at a ratio of
From the viewpoint of the volatility of the lubricant, glycerin, ethylene glycol, propylene glycol, fatty acid esters thereof and water are preferable.

  In the case of (A) alone, the lubricant can be used as it is, and when the polyether (A) and other polyalkylene polyol (B) are used in combination, they can be uniformly mixed and produced by an ordinary method.

In the clay composition of the present invention, known ceramic particles and binders (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.

  In the clay composition of the present invention, from the viewpoint of shape retention in the degreasing step, the binder content (% by weight) is preferably 1 to 10, more preferably 2 to 8, based on the weight of the ceramic particles. Especially preferably, it is 3-6.

  In the clay composition of the present invention, from the viewpoint of extrudability, the content (% by weight) of the lubricant for ceramic material of the present invention is preferably 1 to 10, more preferably based on the weight of the ceramic particles. 3 to 8, particularly preferably 2 to 6.

The clay composition of the present invention may further contain a known dispersing agent and solvent (JP 2004-203705 A, JP 2002-37673 A, etc.) as necessary. When a known dispersant is contained, the content (% by weight) may be appropriately selected from the viewpoint of ease of handling, but is preferably 0.1 to 5 based on the weight of the ceramic particles.
When a known solvent is contained, the content (% by weight) may be appropriately selected from the viewpoint of ease of handling, but is preferably 5 to 100 based on the weight of the ceramic particles.

  As a method for producing the kneaded clay composition, a known method (Japanese Patent Laid-Open No. 2002-37673, etc.) can be applied. First, ceramic particles and a dispersant (such as methyl cellulose) are dry blended, and further water, lubricant, etc. And mixing with a kneader or the like. The mixing temperature is preferably 5 to 50 ° C.

  The kneaded clay composition of the present invention is suitable as a kneaded clay composition used for producing a ceramic molded body by extruding and molding the kneaded clay composition.

As a method for producing a ceramic molded body using the clay composition of the present invention, a known method (JP 2002-37673 A) or the like can be applied, and the clay composition of the present invention is extruded. It is preferable to include a step of obtaining an extruded product and a step of firing the extruded product to obtain a fired product.
The step of obtaining a 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 is left as it is. It becomes a ceramic molded body).

  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.

<Example 1>
A SUS autoclave equipped with a thermometer and a stirrer was charged with 114 g of methanol, 1280 g of tetrahydrofuran and 39 g of boron trifluoride / tetrahydrofuran complex, and the gas phase was replaced with nitrogen. Subsequently, 117 g of ethylene oxide was added dropwise at 45 to 55 ° C. over 1 hour with stirring. After aging at 55 ° C. for 1 hour, the mixture was neutralized with caustic soda solution, and unreacted tetrahydrofuran was removed. The salt formed as a by-product was separated by filtration to obtain a random addition product (molecular weight 300) (A-1) of methanol / tetrahydrofuran / ethylene oxide (molar ratio 80/20).

<Example 2>
A SUS autoclave equipped with a thermometer and a stirrer was charged with 9 g of sorbitol, 409 g of tetrahydrofuran, and 39 g of boron trifluoride / tetrahydrofuran complex, and the gas phase was replaced with nitrogen. Next, with stirring, 322 g of ethylene oxide and 424 of propylene oxide were added dropwise at 45 to 55 ° C. over 5 hours. After aging at 55 ° C. for 3 hours and neutralizing with caustic soda solution, unreacted tetrahydrofuran was removed. The salt formed as a by-product was separated by filtration to obtain a random addition product (molecular weight 20000) (A-2) of tetrahydrofuran / ethylene oxide / propylene oxide (molar ratio 20/40/40) of sorbitol.

<Example 3>
A SUS autoclave equipped with a thermometer and a stirrer was charged with 24 g of hexylene glycol, 1156 g of tetrahydrofuran and 39 g of boron trifluoride / tetrahydrofuran complex, and the gas phase was replaced with nitrogen. Next, 283 g of ethylene oxide was added dropwise at 45 to 55 ° C. over 1 hour with stirring. After aging at 55 ° C. for 1 hour, the mixture was neutralized with caustic soda solution, and unreacted tetrahydrofuran was removed. The salt formed as a by-product was separated by filtration to obtain a random addition product (molecular weight 5000) (A-3) of tetrahydrofuran / ethylene oxide (molar ratio 60/40) of hexylene glycol.

<Example 4>
A SUS autoclave equipped with a thermometer and a stirrer was charged with 46 g of n-butanol, 829 g of tetrahydrofuran and 39 g of boron trifluoride / tetrahydrofuran complex, and the gas phase was replaced with nitrogen. Next, 456 g of ethylene oxide was added dropwise at 45 to 55 ° C. over 1 hour with stirring. After aging at 55 ° C. for 1 hour, the mixture was neutralized with caustic soda solution, and unreacted tetrahydrofuran was removed. The by-product salt was filtered off to obtain a random adduct (molecular weight 1000) (A-4) of tetrahydrofuran / ethylene oxide (molar ratio 40/60) of n-butanol.

<Example 5>
A SUS autoclave equipped with a thermometer and a stirrer was charged with 70 g of water, 500 g of tetrahydrofuran, and 39 g of boron trifluoride / tetrahydrofuran complex, and the gas phase was replaced with nitrogen. Next, while stirring, 365 g of ethylene oxide and 300 g of butylene oxide were added dropwise at 45 to 55 ° C. over 10 hours. After aging at 55 ° C. for 3 hours, the mixture was neutralized with caustic soda solution, and then unreacted water and tetrahydrofuran were removed. The salt formed as a by-product was separated by filtration to obtain a water / tetrahydrofuran / ethylene oxide / butylene oxide (molar ratio 25/50/25) random adduct (molecular weight 480) (A-5).

<Example 6>
A SUS autoclave equipped with a thermometer and a stirrer was charged with 25 g of n-butanol, 1008 g of tetrahydrofuran and 39 g of boron trifluoride / tetrahydrofuran complex, and the gas phase was replaced with nitrogen. Subsequently, 370 g of ethylene oxide was added dropwise at 45 to 55 ° C. over 1 hour with stirring. After aging at 55 ° C. for 1 hour, the mixture was neutralized with caustic soda solution, and unreacted tetrahydrofuran was removed. The salt formed as a by-product was filtered off to obtain a random adduct (molecular weight 3000) (A-6) of tetrahydrofuran / ethylene oxide (molar ratio 50/50) of n-butanol.

<Production Example 1>
A SUS autoclave equipped with a thermometer and a stirrer was charged with 12 parts of ethylene glycol and 1 part of sodium hydroxide, and the interior of the container was sufficiently purged with nitrogen, then sealed and heated to 150 ° C. 426 parts of ethylene oxide and 562 parts of propylene oxide were blown and reacted at 150 ° C. for 5 hours. The mixture was further aged at 150 ° C. for 1 hour and then cooled to 25 ° C. to obtain ethylene glycol / ethylene oxide / propylene oxide (molar ratio 50/50) random adduct (molecular weight 5000) (B-1) of ethylene glycol.

<Production Example 2>
A SUS autoclave equipped with a thermometer and a stirrer was charged with 99 parts of methanol and 1 part of sodium hydroxide, and after the inside of the container was sufficiently purged with nitrogen, the container was sealed and heated to 100 ° C. 901 parts of propylene oxide was blown into the reaction at 100 ° C. for 20 hours. Further, after aging at 180 ° C. for 1 hour, the mixture was cooled to 25 ° C. to obtain a propylene oxide adduct of methanol (molecular weight 300) (B-2).

<Example 7>
Cordierite prepared by adjusting the chemical composition of kaolin, talc, silica, aluminum hydroxide, and alumina powder so that the chemical composition is SiO ₂ : 48 to 52 wt%, Al ₂ O ₃ : 33 to 37 wt%, and MgO: 12 to 15 wt%. 100 parts of ceramic raw material, 4 parts of methyl cellulose {“Metroses (registered trademark) 90SH-3000”, manufactured by Shin-Etsu Chemical Co., Ltd.} are dry blended with a high shear mixer (25 ° C.), 25 parts of water, (A-1) 4 An aqueous solution mixed with parts was added and further kneaded to obtain a clay. This kneaded material was packed into a 12 mmφ piston with a 7.5 mmφ cap attached to the tube tip, and a molded body was obtained by extruding the piston at an extrusion speed of 6 mm / s. At this time, the load applied to the piston was measured, and the maximum value was shown in Table 1 as the extrusion load at the time of extrusion molding. The hardness of the clay (by the following method) was measured and is shown in Table 1.

<Hardness of clay>
After the extrusion test, the clay remaining in the piston was taken out, and the hardness was measured using an NGK hardness tester (manufactured by NGK) with the measuring probe perpendicular to the surface.
It measured 10 times about different places with said method, and made this arithmetic average value the hardness of clay.

<Example 8>
Extruded bodies and ceramic molded bodies were obtained in the same manner as in Example 1 except that (A-1) 4 parts were changed to (A-2) 10 parts. Table 1 shows the extrusion load during extrusion molding and the hardness of the clay in the same manner as in Example 1.

<Example 9>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 1 except that (A-1) 4 parts were changed to (A-3) 2 parts and (B-1) 8 parts. Table 1 shows the extrusion load during extrusion molding and the hardness of the clay in the same manner as in Example 1.

<Example 10>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 1 except that (A-1) 4 parts were changed to (A-4) 4 parts and (B-1) 1 part. Table 1 shows the extrusion load during extrusion molding and the hardness of the clay in the same manner as in Example 1.

<Example 11>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 1 except that (A-1) 4 parts were changed to (A-5) 1 part. Table 1 shows the extrusion load during extrusion molding and the hardness of the clay in the same manner as in Example 1.

<Example 12>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 1 except that (A-1) 4 parts were changed to (A-6) 4 parts. Table 1 shows the extrusion load during extrusion molding and the hardness of the clay in the same manner as in Example 1.

<Comparative Example 1>
Extruded compacts and ceramic compacts were obtained in the same manner as in Example 1 except that (A-1) was not used. Table 1 shows the extrusion load during extrusion molding and the hardness of the clay in the same manner as in Example 1.

<Comparative example 2>
Extruded bodies and ceramic molded bodies were obtained in the same manner as in Example 1 except that (A-1) 4 parts were changed to (B-1) 1 part. Table 1 shows the extrusion load during extrusion molding and the hardness of the clay in the same manner as in Example 1.

<Comparative Example 3>
Extruded bodies and ceramic molded bodies were obtained in the same manner as in Example 1 except that (A-1) 4 parts were changed to (B-2) 4 parts. Table 1 shows the extrusion load during extrusion molding and the hardness of the clay in the same manner as in Example 1.

  As shown in Table 1, the clay composition (Examples 7 to 12) using the lubricant of the present invention contains ceramics and the like because the load during extrusion is smaller than that of Comparative Examples 1 to 3. It is assumed that the extrudability is good because the adhesiveness of the composition is reduced and the slip in the die is improved.

Claims (6)

A lubricant for a ceramic material, comprising a polyether (A) obtained by adding tetrahydrofuran and 1,2-alkylene oxide having 2 to 4 carbon atoms to water or 1 to 6-valent alcohol. The lubricant according to claim 1, wherein the 1,2-alkylene oxide having 2 to 4 carbon atoms is ethylene oxide. The lubricant according to claim 1 or 2, wherein the molar ratio of the polyether (A) to tetrahydrofuran and 1,2-alkylene oxide is 20/80 to 80/20. The lubricant according to any one of claims 1 to 3, wherein the content of (A) is 20 to 100% by weight. A clay composition for extrusion molding, comprising a composition comprising ceramic particles, a binder, and water containing the lubricant according to any one of claims 1 to 4. A method for producing a ceramic molded body by firing an extruded molded body of a composition comprising ceramic particles, a binder, and water, wherein the composition contains the lubricant according to any one of claims 1 to 4. A method for producing a ceramic molded body.