JPS61291469A - Manufacture of ceramic structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing a ceramic structure. More specifically, the present invention relates to a method for producing a porous ceramic structure useful for collecting carbon particulates contained in the exhaust gas of a diesel internal combustion engine or as a catalyst support.

[Prior Art] Conventionally, as a method for manufacturing porous ceramics, a method has been known in which a ceramic slurry is attached to an organic polymer foam, such as a polyurethane foam from which the cell membrane has been completely removed, and then dried and fired (Japanese Patent Laid-Open No. 1983-1995). -111817, same 2
4585); In addition, as a method for producing a porous ceramic having a plurality of columnar hollow holes parallel to each other (adjacent hollow holes open in opposite directions), a mold cavity having the same shape as the above-mentioned ceramic is used. There is also a method known in which an organic compound having a three-dimensional network skeleton is foamed, the resulting organic compound foam is subjected to film removal treatment, and a ceramic slurry is immersed in it, dried and fired (Japanese Patent Laid-Open No. 58-161).
Publication No. 962〉.

[Problems to be Solved by the Invention] The organic polymer foam used to produce such porous ceramics is required to have no cell membrane, and in the case of polyurethane mold foam, chemical (alkali) or heat treatment is required. (combustion) treatment is required to completely remove the cell membrane, and with conventional polyurethane mold foam, such membrane removal treatment takes a long time, and if the treatment is carried out for too long, the cell skeleton may collapse. However, there is a need for something that does not require such membrane removal treatment, or that can produce a porous ceramic with a sufficient membrane removal effect in a short time.

[Means for solving the problem] According to the present invention, a polyurethane foam obtained by a combination of two specific types of polyether polyols is suitable for the production of porous ceramics as described above, particularly in JP-A-58-16.
No. 1962 was found to be useful.

That is, in the present invention, when a porous ceramic structure is produced by attaching a ceramic slurry to an organic polymer foam, drying and firing, organic polyisocyanate and amine-based polyether polyol (a) are used as the foam. A method for producing a ceramic structure (No. A plurality of columnar hollow holes parallel to each other are provided inside the ceramic so as to form a lattice-like arrangement in a cross section perpendicular to the axis of the hollow holes, and one end of the columnar hollow hole is connected to one end of the ceramic. A porous ceramic structure that is open at one end face, the other end is sealed at the other end face of the ceramic, and adjacent columnar hollow holes open in opposite directions across the hollow hole walls arranged in a lattice pattern. In the manufacturing method, the mold container portion is composed of an end face and a side wall to which a columnar member for forming a group of columnar hollow holes opening in the same direction is fixed, and the other end face is open; The cavity of the mold formed by engaging the mold lid to which the columnar member for forming the columnar hollow hole group is fixed has the same shape as the above-mentioned ceramic, and in the mold cavity, the organic polyisocyanate and A step of mold-foaming the amine-based polyether polyol (a) and the non-amine-based polyether polyol (b) in the presence of a silicone foam stabilizer, a tertiary amine catalyst, and a blowing agent to obtain a foam having the same shape as ceramics. and a step of impregnating the foam obtained in the above step with a ceramic slurry, drying and firing the method (second invention).

Amine-based polyether polyol (a
) is a compound having a structure in which an alkylene oxide is added to an amine having two or more active hydrogen atoms.

The active hydrogen atom-containing amines include, for example, monoamines such as ammonia and butylamine; aliphatic polyamines such as ethylenediamine, hexamethylenediamine, and diethylenetriamine; alicyclic polyamines such as cyclohexylenediamine and isophoronediamine @: phenylenediamine , aromatic polyamines such as tolylene diamine, xylene diamine, diphenylmethanediamine, polyphenylmethane polyamine, diethyltolylene diamine; heterocyclic polyamines such as piperazine and IN-aminoethylpiperazine; and monoethanolamine, Examples include alkanolamines such as jetanolamine and triethanolamine. Two or more kinds of the above-mentioned amines can also be used.

Examples of the alkylene oxide to be added to the above amines include ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide, and epichlorohydrin. The alkylene oxides may be used alone or in combination of two or more, and in the latter case, block addition, random addition, or a mixture of both may be used. Among these alkylene oxides, propylene oxide and/or ethylene oxide are preferred, but depending on the required performance, small amounts of other alkylene oxides (butylene oxide, tetrahydrofuran, styrene oxide, etc.) may be used in combination with these. good. From the viewpoint of reactivity, a combination system of propylene oxide and ethylene oxide (usually 7 by weight) is preferable.
0:30-95:5 especially 80:20-90
: 10). Addition of alkylene oxide can be carried out in the usual manner1, either without catalyst or in the presence of a catalyst (alkali catalyst, amine catalyst, acid catalyst) (particularly in the latter stages of alkylene oxide addition) at normal pressure or under pressure. It is done under pressure.

The amine polyether polyol (a) usually has an OH value of 10 to 701, preferably 20 to 50. If the OH number is less than 10, the foam will be too soft and the shape retention of the molded product will be poor, and if the OH number is 70 or more, the foam will have poor air permeability due to a lot of skin and cell membranes on the mold surface. . The (average) number of functional groups in (a) is usually 2 to 8
Preferably it is 2-4.

Among (a), preferred are those having an oxyethylene chain at the end [chip type, balanced type, random chip type (having a random polyoxyethylene/oxypropylene chain inside)].

The terminal oxyethylene group content is usually 5% (weight %, the same applies hereinafter) or more, preferably 5 to 30%, more preferably 1
It is 0-20%. If the oxyethylene chain content is less than 5%, curing immediately before the end of foaming will be insufficient and the foam will collapse. Total oxyethylene group content is usually 5-50
% is preferably 10-30%.

In addition, the non-amine polyether polyol (b) used in the present invention includes polyhydric alcohols, polyhydric phenols,
Examples include compounds having a structure in which alkylene oxide is added to a polyfunctional compound containing an active hydrogen atom, such as polycarboxylic acid. The above polyhydric alcohols include ethylene glycol, propylene glycol, 1,4-butanediol, 1
．． - Dihydric alcohols such as 6-hexanediol, diethylene glycol, and neopentyl glycol, trihydric alcohols such as glycerin and trimethylolpurpane, and tetrahydric or higher alcohols such as pentaerythritol, sorbitol, and sucrose: as polyhydric phenols In addition to polyhydric phenols such as pyrogallol and hydroquinone, bisphenols such as bisphenol A, novolak resins having two or more phenolic hydroxyl groups, and intermediates of resol resins; polycarboxylic acids include fats such as succinic acid and adipic acid. Examples include aromatic polycarboxylic acids such as group polycarboxylic acids, phthalic acid, terephthalic acid, and trimellitic acid. Two or more kinds of the above-mentioned active hydrogen atom-containing compounds can also be used. Examples of the alkylene oxide added to the above active hydrogen atom-containing compound include ethylene oxide, propylene oxide, butylene oxide,
Examples include tetrahydrofuran, styrene oxide, and epichlorohydrin. The alkylene oxides may be used alone or in combination of two or more, and in the latter case, block addition, random addition, or a mixture of both may be used. Among these alkylene oxides, preferred is the combination of ethylene oxide and other alkylene oxides. Among the other alkylene oxides, propylene oxide is preferred, but a small amount of other alkylene oxides (butylene oxide, tetrahydrofuran, styrene oxide, etc.) may be used in combination depending on the required performance. From the viewpoint of reactivity, a combination system of propylene oxide and ethylene oxide (usually 70:30 to 95:5, especially 80:20) is preferable from the viewpoint of reactivity.
~90:10). The alkylene oxide addition can be carried out in the usual manner, either without catalyst or in the presence of a catalyst (alkali, amine, acid), especially in the latter stages of the alkylene oxide addition, at normal or elevated pressure. It will be held on.

Non-amine polyether polyol (b>0Hfi[
fi is usually 10-70, preferably 20-50. If the OH number is less than 10, the foam will be too soft and the shape retention of the molded product will be poor, and if the OH number is 70 or more, the foam will have poor air permeability due to a lot of skin and cell membranes on the mold surface. . The (average) number of functional groups in (b) is usually 2 to 8, preferably 2 to 4.

Among (b), preferred are those having an oxyethylene chain at the end [chip type, balanced type, random chip type (having a random polyoxyethylene/oxypropylene chain inside)].

The terminal oxyethylene group denominator is usually 5% or more, preferably 5 to 30%, more preferably 10 to 20%. When the oxyethylene chain content is less than 5%, curing immediately before the end of foaming becomes insufficient and the foam tends to collapse, which is not preferable. If the oxyethylene chain content exceeds 30%, the number of closed cells increases, making it virtually impossible to crush, and the foam shrinks.

The ratio (weight ratio) of the amine polyether polyol (a) and the non-amine polyether polyol (b) is usually 5:95 to 70:30. Preferably 10:90-50:
It is 50. If (a) is less than the above range, the mold form will have many surface skins and cell membranes, while if it is more than the above range, the cells of the foam will tend to partially collapse.

In the present invention, the tertiary amine used in combination as a catalyst includes a tertiary amine that promotes the resin formation reaction, a tertiary amine that promotes the foaming reaction, and especially a combination system of both.

Tertiary amines that promote the resin formation reaction include those effective as catalysts for the reaction between alcohol and isocyanate, such as triethylenediamine, tetramethylethylenediamine, tetramethylhexylenediamine, 1,8-diaza-bicyclo[5,4 , Ol undecene-7, and polyamines represented by the following general formula (1) [dialkylaminoalkyls such as dimethylaminoethylamine, dimethylaminopropylamine, diethylaminepropylamine, dibutylaminoethylamine, dimethylaminooctylamine, and dipropylaminopropylamine] Amines: 2-(1-aziridinyl)ethylamine, 4-(1
-piperidinyl)-heterocyclic aminoalkylamines such as 2-hexylamine] or organic acid salts (
formate, etc.).

In the U formula, R1 and R2 are each an alkyl group having 1 to 4 carbon atoms (methyl, ethyl, n- or 1so-propyl, n- or 1so-butyl, etc.; preferably methyl), and R1 and R2 are mutually may be bonded to a divalent group (ethylene, n- or 15O-propylene, tetramethylene, pentamethylene, etc.) to form a 3- to 6-membered heterocycle together with the nitrogen atom. R3 is an alkylene group (an alkylene group having 2 to 12 carbon atoms, such as a linear or branched alkylene group such as ethylene, n-propylene, tetramethylene, hexamethylene, 2-ethylhexylene, decamethylene, etc.; preferably ethylene,
n-propylene and 0-butylene groups). Among these catalysts, preferred are triethylenediamine and carbonates or organic acid salts (especially formates) of polyamines of general formula (1) (especially dimethylaminopropylamine, dimethylaminoethylamine).

Tertiary amines that promote the foaming reaction include those effective as catalysts for the reaction between water and isocyanate, such as N-
Examples include methylmorpholine, N-ethylmorpholine, triethylamine, diethylethanolamine, dimethylethanolamine, and the like. Preferred is he-ethylmorpholine.

The amount of resin conversion catalyst used is usually 0.1 to 260 parts, preferably 0.5 to 1.5 parts, per 100 parts of polyol. If it is less than 0.1 part, the resin formation reaction is slow and curing takes a long time. On the other hand, if the amount exceeds 2.0 parts, a skin will easily form on the surface of the mold foam, resulting in poor air permeability. Among the resinization catalysts, the amount of polyamine salt (carbonate, formate) represented by general formula (1) used is usually 0.2 to 2.0 parts, preferably 0.5 to 1.5 parts, per 100 parts of polyol. Department. If it is less than 0.2 parts, the performance of the ceramic foam for this purpose will be significantly reduced and the cells of the foam will collapse;
If it exceeds 50%, a skin will easily form on the surface of the mold form and the air permeability will deteriorate. The amount of other resin conversion catalysts used is usually 0.01 part to 0.2 part per 100 parts of polyol.
Preferably it is 0.02 to 0.1 part. If it is less than o or oi parts, the resin formation reaction is slow and curing takes a long time. Also,
If it exceeds 0.2 part, a skin will easily form on the surface of the mold foam, resulting in poor air permeability.

The amount of blowing catalyst is usually 0.2 per 100 parts of polyol.
~1.5 parts, preferably 0.4 to 1.0 parts.

If the amount is less than 0.2 part, foaming will be slow and the mold foam will have more surface skin. When the amount is more than 1.5 parts, foaming becomes too fast, the foam cells become fine, and air permeability deteriorates.

The ratio of resin forming catalyst and foaming catalyst is usually 80:20 to 30.
Near 0. Preferably it is 70:30 to 50:50.

The ratio of carbonate or formate of the polyamine of general formula (1), other resin forming catalyst, and foaming catalyst is usually 40 to 75:1.
~5:25~60. Preferably 50-65: 1-2:
It is 35-45. The total amount of these catalysts is usually 1.0 to 3.0 parts per 100 parts of polyol.

As the organic polyisocyanate used in the present invention, those conventionally used in the production of polyurethane can be used. For example, aliphatic polyisocyanates (hexamethylene diisocyanate, lysine diisocyanate, etc.), alicyclic polyisocyanates, dicyclohexylmethane diisocyanate, isophorone diisocyanate, aromatic polyisocyanates [tolylene diisocyanate (TD I >, diphenylmethane diisocyanate (MD I), naphthi diisocyanate, xylylene diisocyanate, etc.] and mixtures thereof.Among these, aromatic diisocyanates are preferred, and particularly preferred are TDI, M
It is DI. These polyisocyanates include crude polyisocyanates such as crude TDI, crude MDI [crude diaminodiphenylmethane (condensation product of formaldehyde and aromatic amines or mixtures thereof) diaminodiphenylmethane and a small amount (for example 5 to 20 FJ!%) of 3
Phosgene compounds (mixtures with higher than functional polyamines):
It can also be used as polyallyl polyisocyanate (PAPI). Alternatively, modified polyisocyanates such as liquefied MDI (carposiimide modification, trihydrocargel phosphate modification, etc.) or excess polyisocyanate (TDI, MDI or modified products thereof, etc.)
It can also be used as a free isocyanate-containing prepolymer obtained by reacting polyisocyanate with a polyol, or they can be used in combination (for example, a modified polyisocyanate and a prepolymer are used together). The polyol used for producing the above prepolymer usually has an equivalent weight of 30 to 20.
0 polyols such as glycols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, trimethylolpropane,
Triols such as glycerin; pentaerythritol,
Highly functional polyols such as sorbitol; and alkylene oxide (ethylene oxide and/or propylene oxide) adducts thereof. Among these, those having 2 to 3 functional groups are preferred.

The free isocyanate group content of the modified polyisocyanate and prepolymer is generally 10 to 30%, preferably 15 to 30%, particularly preferably 20 to 30%. Among organic polyisocyanates, preferred is a mixture of TDI and crude MDI (weight ratio, for example, 95 to 5:3).
0-70, preferably 90:10-50:50).

As the blowing agent, water and/or a halogen-substituted aliphatic hydrocarbon blowing agent (fluorocarbons such as trichloromonofluoromethane) can be used. Preferred is water.

In the present invention, the free foam density is 0.02 to 0.0.
It is preferable to adjust the amount of the blowing agent to be within the range of 4'j/cm. Free foam density is 0.02 g/
If the C/A is less than 0.049/crd, the cells of the molded foam will become rough, and if it is higher than 0.049/crd, a strong surface skin will form on the mold surface.

The amount of foam stock solution injected into the mold is preferably adjusted to a pack rate (excess filling rate) of 120 to 300%. In other words, 1 of the minimum required amount of foam stock solution (injection amount in the case of free foaming) calculated from the internal volume of the mold.
．． Inject 2 to 3 times the amount. When the packing ratio is less than 120%, the cells of the mold form become rough and the cells collapse. If the packing ratio exceeds 300%, the cells in the mold form will be fine, resulting in a strong cell membrane, a large surface skin, poor ventilation, and rapid foaming, and too much foaming pressure, which will significantly reduce workability during mold injection. -1 If necessary, pigments, fillers, flame retardants, thixotropic agents, etc. can also be added to the foam stock solution.

In the present invention, the foam can be manufactured using conventional mold foaming techniques. For example, polyol is mixed with a foaming agent, a catalyst, a foam stabilizer, etc. to form liquid A, and liquid B is prepared in advance with an organic isocyanate, which is then filled into a tank of a low-pressure foaming machine. Pour the polyurethane foam stock solutions (solution A and solution B) into the open mold using a mixing head.
The lid is tightened, and after foaming is completed, the product is placed in a curing oven at 80 to 150°C and molded after curing. Isocyanate index is usually 70
-1201 preferably 80-110.

The surface skin and cell membrane of the obtained foam can be completely removed by treatment with an alkaline aqueous solution or by a combustion method, if necessary.

Examples of the alkali include Na0HSKOH. The concentration of the aqueous solution is usually 20-50%. The alkaline aqueous solution treatment can be carried out using conventional methods and conditions. For example, the mold form is immersed in a 30% alkaline aqueous solution at 80 to 90° C. for 15 to 20 hours to remove the film.

Further, examples of the combustion gas used in the combustion method include a mixed gas of propane, butane, etc., and oxygen.

The mixing ratio (weight ratio) of propane and oxygen is usually 5:95 to 1
It was 4:85. Film removal using the combustion method can be performed under generally known methods and conditions.

For example, put the foam in an airtight container and store about 400rr.
After reducing the pressure to mHcJ, propane 7%, oxygen 93%
Add a mixed gas of 1 to 760 mHg, ignite and burn to remove the film.

In the present invention, amine-based polyether polyol (a
) and the non-amine polyether borion factor b) can be used to produce a porous ceramic structure using a polyurethane foam that is foamed in combination with a conventional method. 24585@, Japanese Patent Publication No. 5
Examples thereof include those described in JP-A No. 5-111817, JP-A-58-161962, JP-A-58-91048@, and JP-A-58-151382.

The raw material for the ceramic slurry used for impregnation is MqO1AIz03.5i, which becomes cordierite after firing.
A mixed powder containing Oz, or a synthetic cordierite powder made by heating the above mixed powder to make cordierite ceramics and powdering it, or a mixture of both with methylcellulose, ethylcellulose, polyvinyl alcohol, polyvinyl butyral, etc. Although it is preferable to use a binder with water added thereto, it is not necessarily limited to these, and other known ceramic raw materials may be used. Further, the firing treatment may be performed at a generally known temperature and time. Desirably, the temperature is 1300 to 1470°C for 5 to 6 hours.

The porous ceramic produced according to the present invention (second invention) generally has a columnar shape such as a columnar shape or an elliptical columnar shape, but the outer shape is not limited, and the end surface may be curved. The cross-sectional shape of the columnar hollow hole formed inside the ceramic can be a circle, a regular triangular square, a square, a regular hexagon, etc., but is not necessarily limited to these shapes. Further, the size and number of hollow holes, the thickness of the hollow hole wall, and the thickness of the hollow hole sealing portion can be arbitrarily selected.

The mold consists of a mold container part and a mold lid part, each having a cavity formed in a similar shape to the porous ceramic that is the intended product. The mold container portion includes columnar members having substantially the same cross-sectional shape and length as the cross-sectional shape of the hollow holes opening in the same direction, and are arranged in a lattice pattern at appropriate intervals. On the other hand, the mold cover is provided in a grid pattern at appropriate intervals and has approximately the same cross section and length as the hollow holes opening in the same direction. Then, the mold container part and the mold lid part are assembled so as to be engaged with each other to obtain a mold. At this time, the columnar members of the mold lid part fit into the space between the columnar members of the mold container part, and when the two parts are combined, the polyurethane foam stock solution should be foamed between these columnar members. Appropriate space (cavity)
exists. This mold cavity has approximately the same shape as the porous ceramic that is the target article to be manufactured, and is constructed in a size that takes into account shrinkage due to firing, which will be described later.

The foam stock solution is foamed in the mold configured as described above. In addition, the foaming process can be performed by assembling the molds and then injecting the foam stock solution. When the molds are assembled, the foam stock solution is injected into the vessel, and the mold lid is quickly assembled, allowing foam to form inside the mold and excess foam. The foam undiluted solution may be discharged. In addition, during foaming, the roughness of the network of the porous ceramic can be freely adjusted by adjusting the mixing ratio of the foaming agent, silicone foam stabilizer, catalyst, etc. Also,
It is desirable to coat the inside of the molded body with a suitable mold release agent or to perform a surface treatment such as Teflon treatment so that the organic compound can be easily removed from the molded body after foaming. .

[Example] The manufacturing method of the present invention will be specifically explained below with reference to Examples. Note that parts and % represent parts by weight and % by weight, respectively.

The foam raw materials used below are as follows.

Boliole: A non-amine polyether polyol with a molecule fi5QOo obtained by addition polymerizing 4258 parts of propylene oxide to 92 parts of glycerin and 650 parts of ethylene oxide.

Polyol ■ Molecule fi60 made by addition-polymerizing 5151 parts of propylene oxide to 129 parts of niaminoethylpiperazine and then addition-polymerizing 720 parts of ethylene oxide.
00 polyether polyol.

Catalyst ■ Nitriethylenediamine catalyst ■: N-ethylmorpholine catalyst ■ Nidimethylaminopropylamine oxalate foaming agent ■ Nitrichloromonofluoromethane foam stabilizer ■: Silicone foam stabilizer 3-5246 [manufactured by Goldschmidt] Isocyanate ■ : Isocyanate made by blending Dine DI-80 and Crude MDI in a ratio of 80:20.

Foam production example 1 70 parts of polyol I and 30 parts of polyol II
part, 4.0 parts of water, 3 parts of catalyst IO, catalyst ■
Add 41.2 parts of isocyanate I to a premix containing 0.6 parts of catalyst, 0.9 parts of catalyst, 10 parts of blowing agent I, and 1.5 parts of foam stabilizer, and stir and mix at a speed of 11,000 RP for 10 seconds. After that, mold a mold (30 cm
The mixture was poured into a 30 cm x 5 cm (manufactured by Affl), the lid was closed, and the mixture was foamed in the mold. After 3 minutes had passed after the completion of foaming, it was cured in an oven at 100°C for 30 to 45 minutes.

The resulting foam was examined for surface skin cell membrane properties, air permeability, and general mechanical properties using the following evaluation methods.

(Form evaluation method) Area of A9 surface skin: The area covered by the skin is shown in % when the area of the mold foam surface is taken as 100. The smaller the area of the surface skin, the more breathable the foam will be.

B. Amount of cell membrane: Cut the mold form, observe the state of the cells on the cut surface with a magnifying glass, count how many cells with cell membranes are present within a 10 cm length, and indicate in percentage. The smaller the amount of cell membrane, the better the air permeability, and the better the foam is, the smaller the pressure loss when used as a filter.

C. Alkali treatment time: The obtained mold form was
The time required for the surface skin cell film to completely disappear after immersion in a 30% alkaline aqueous solution at 0 to 120'C is shown.

The shorter the processing time, the easier it is to obtain a completely skinless mold frame with less cell membranes.

D0 Mechanical properties: Examine tensile strength, elongation, tear strength, compressive strength, permanent set, air permeability, etc. A mold form with excellent mechanical strength is suitable as a cushioning material.

E. Internal collapse of cells: The mold form was cut and the state of the internal cells was observed. When the cell skeleton collapsed and several cells joined together, it was determined that cell collapse was inevitable.

The results of the evaluation test are shown in Table 2.

Foam production examples 2 to 8 Ratio of amine polyether polyol (a) and non-amine polyether polyol (b), catalyst (catalyst ■,
The same procedure as in Example 1 was carried out except that the amount of catalyst (1) or the overpack ratio was changed.

The foaming prescription and evaluation results are shown in Tables 1 and 2, respectively.

Example 1 Silica (SiOz>46%, alumina (Ai0203>
Formulation 10 consisting of talcum kaolin and phaeiarite formulated to a chemical composition of 32% ferrous oxide (Fed) and 22% ferrous oxide (Fed)
0 parts, 60 parts of water, 1 part of polyvinyl alcohol as a binder, and 1 part of a surfactant were mixed and thoroughly stirred to form a slurry.

The polyurethane foam obtained in Foam Preparation Example 2 was dipped into this, then pulled up and dried at 120°C for 1 to 3 hours. This operation was repeated two to three times to obtain a slurry thickly deposited on the polyurethane foam skeleton.

Next, silica (SiOz>51%), alumina (Ai203
) and 14% magnesia (MqO) was made into a slurry in the same manner as described above. The slurry-adhered polyurethane foam was immersed in this solution and then dried at 120'C for 1 to 3 hours. This operation was repeated 2 to 3 times.

The slurry-adhered polyurethane foam obtained in this manner was fired at 1400°C for 3 hours to obtain a ceramic structure with a three-dimensional network structure.

Example 2 Next, a specific method for manufacturing a ceramic structure (filter material) using the method of the present invention will be described below, including the structure of the foam molded body and the structure of the mold.

(1) Structure of foam molding and filter material FIG. 1(a) shows an external perspective view of the foam molding and filter material 200, and FIG. 1(b) shows a sectional view of essential parts of the molding. The foam molded body and the filter material have a cylindrical shape as a whole, and a large number of hollow holes 20 are provided from both ends of the molded body and the filter material so as not to intersect with each other. , with the other end as the outlet section 24. Adjacent hollow holes 20 are closed at their ends 22, and a partition wall is located between the hollow holes 20. They communicate with each other via 1. This partition wall 21 has a three-dimensional network structure as shown in FIG. 2, and has through holes 212 formed between its skeleton 211.
It is designed to allow air to pass through. Note that the end portion 22 also has a structure as shown in FIG. 2, but the through hole 212 is made very small due to the foaming pressure.

(2) Structure of the mold Figure 3 shows the container part of the mold used in the structure of the foam molded article, and Figure 3 (a) is a plan view;
FIG. 3(b) is a sectional view. The mold container part 1 consists of an end face 5 and a side wall 2, in which columnar members 3 having a square cross section smaller than the area of the compartment are vertically fixed in every other compartment divided on a base, and the other end faces are open. ing.

On the other hand, FIG. 4 shows a mold lid part combined with the mold container part 1, with FIG. 4(a) being a plan view and FIG. 4(b) being a sectional view. The mold-lid part 10 is composed of a flat plate lid 15 to which a columnar member 13 is vertically fixed, similar to the mold container part 1 described above. The columnar members 13 are attached to grid-like sections of the mold container section 1 where the columnar members 13 are not attached. In addition, communication holes 16 are provided in each section of the flat plate of the mold lid 10, and communication holes 17 are provided in the side periphery of the flat plate.

A mold is created by combining the mold container part 1 having such a configuration and the molded/sculpted lid part 10. FIG. 5 shows a cross section of the assembled mold.

A cavity 18 having the same shape as the foam molded body to be manufactured is formed inside this mold. The mold lid 10 and the mold container 1 are removably fixed with screws 19 through a communication hole 17 provided on the side periphery of the mold lid 10 so that a predetermined combination can be achieved.

(3) Foam molded product! Now, a specific method for manufacturing a foam molded article using the mold having the above configuration will be described.

(a) Polyol I described in Foam Production Example 1 above
For 100 parts of a mixture of 70 parts and 30 parts of polyol I, 4.0 parts of water, 0.6 parts of catalyst, 10.9 parts of catalyst, 10 parts of catalyst I, 5 parts of foam stabilizer, Foaming agent I
10 parts, add 41.2 parts of isocyanate I, 11
Stir and mix for 8 seconds at a speed of 000 pp. This mixture is coated inside with a wax-based mold release agent (for example, Bond Wax IRT-35T) (total coating ff11).
．． 5g> of the mold shown in FIG. 5 (mold temperature: 50'C). Note that at this time, the air inside the mold is exhausted from the remaining communication holes 16,
The raw material liquid is well injected. In addition, when injecting urethane foam, the undiluted solution of urethane foam is injected into the mold container part 1, and then the mold lid part 10 is inserted, and the air in the mold and excess urethane foam are poured into the mold lid part 1.
It was also possible to create a structure in which the gas was discharged from a large number of communication holes 16 provided in the 0.

Next, foaming is performed in the cavity 18, and the temperature is 15°C at 80'C.
Heat and cure for ~60 minutes. Thereafter, the mold container part 1 and the mold lid part 10 are removed to obtain a foam molded body.

By the way, in the foam molded article obtained as described above, the foam stabilizer in the raw material liquid, the wax-based mold release agent on the mold surface, and the pressure during foaming combine to cause the mold container part 1 to
The portions of the columnar member 3 and the columnar member 13 of the mold lid 10 are made film-free, so that the columnar members 3, 13 are in contact with each other.
The skin (membrane) is no longer stretched between the three-dimensional network structure skeletons in contact with the membrane, and the membrane becomes breathable.

In addition, when the thickness of the partition wall 21 is 20 m or less (1 to 20 mm) as in the foam molded product shown in FIG. (see Figure 5), the cells of the foam collapse, but this collapse can be prevented by the surface tension of the wax-based mold release agent applied to the inner surface of the mold, which greatly contributes to the molding of skinless foam. Become. Furthermore, the mold shown in FIG. 5 has a structure with good sealing properties that makes it easy to increase the expansion ratio, and this point also contributes to the molding of skinless foam.

Now, the foam molded article produced as described above may be further treated with, for example, a 30% aqueous solution of caustic soda at 80'C to 12°C.
The cell membrane was removed by immersion at 0° C. for about 5 to 30 hours.

In this way, a cylindrical shape with an outer diameter of 120 mm and a length of 150 mm is formed, and a square hollow hole with a - side of 5 mm (marked @20 in Figure 1)
and has a partition wall (reference numeral 21 in FIG. 1) with a thickness of 3 ends, and 1
A foam molded body having a vent size of 0 to 80 meshes was obtained.

(b) Here, an experimental example will be explained to demonstrate the superiority of the present invention. The test specimens had the structure shown in Figures 1 (a) and (b), with a diameter of 127 mm, a length of 110 m, and a partition wall thickness of 3.
#, the size of the vent hole is 60 to 70 mesh, and the size of the hollow hole is a 4 mm square. and,
One of the test products was prepared by the method (3)(a) described above, and the other test products were conventional examples prepared without using the above-mentioned foam stabilizer or mold release agent. In addition, after molding, all of the above test products were heated to 30% at a temperature of 80 to 90°C.
The skin formed on each skeleton was removed by immersion in a NaOH aqueous solution for about 16 hours, thoroughly washed with water, and then dried at 80'C for 2 to 4 hours.

The pressure loss situation when air is flowed through each of the above test items is shown in the 6th section.
As shown in the figure. As can be understood from FIG. 6, the product obtained by the method of the present invention has a significantly lower pressure loss and a remarkable skin removal effect than the conventional method.

In the method for manufacturing the foam molded article described above, the mold release agent used was URT-35T (trade name, manufactured by Bond Wax Co., Ltd.), but it changed from the same phase to a liquid phase at a temperature of ao'C to 90'C. Any wax-based material that has good wettability with the surface of the mold may be used.

(4) Production of ceramic structure Next, the foam molded body was immersed in a ceramic slurry made by mixing and stirring powder mainly composed of cordierite, water, and polyvinyl alcohol, and after removing excess slurry, Dry by heating at 100-120°C, this immersion,
Drying was repeated several times. Then 1300-1470'C
It was baked for about 5 hours at a low temperature. An axial cross-sectional view of the porous ceramic prepared in this manner is shown in FIG. 1(b), and a partially enlarged view of its structure is shown in FIG. 2. The arrows in the figure indicate the travel path of exhaust gas. The exhaust gas flows into the hollow hole 20 from the ceramic inlet portion 23, passes through the porous hollow hole wall 21, flows out into the adjacent hollow hole 20, and flows out from the hollow hole outlet portion 24 to the outside of the ceramic. Carbon particles contained in the exhaust gas are mainly collected by the wall 21 of the hollow 71. Further, the sealing portion 22 of the hollow hole is made integrally with the four-hole wall 21.

By the above means, the outer diameter is 120 #l #I and the length is 1.
It has a cylindrical shape of 50#1171, has a square hollow hole with sides of 5#, and a hollow hole wall with a thickness of 3m, and has a roughness of #40.
porous ceramic structures were produced.

Using this porous ceramic, a test was conducted on the collection efficiency of carbon particles. With a displacement of 2.2 and 11 driving conditions, the carbon particulate emissions were 0.4 g/mile, but the proportion of carbon captured by the porous ceramics was 0.359/mile, meaning the collection rate was 87. .5% was obtained. The pressure loss is 2 when air is passed at 1 go/min.
cmF+20.

In addition, a porous ceramic structure produced from a foam molded body produced without using the above-mentioned foam stabilizer had a collection rate of 75%,
The pressure drop was 8 cmH20 (1rd/min air passage).

[Effects of the Invention] The production method of the present invention is clearly superior to conventional production methods in the following points.

According to the present invention, amine-based polyether polyol (a
) and non-amine polyether polyol (b) and mold-foamed using a tertiary amine catalyst, the polyurethane foam has fewer cell membranes and surface skins than conventional polyurethane foams, and has good air permeability. in,
The cell skeleton is thin, the cells are aligned, and there is little pressure loss, so when this is used to manufacture porous ceramic structures, membrane removal treatment (alkali treatment, etc.) is significantly shorter than conventional methods. (It can be omitted in some cases.)

In conventional foams, the surface skin and cell membrane cannot be sufficiently removed even when treated with an alkaline aqueous solution, and if the alkaline aqueous solution treatment time is prolonged, the cell skeleton collapses and the foam loses its shape. Porous ceramics produced from these had drawbacks such as cell collapse resulting in a foam with no collection function as a filter, large pressure loss, and insufficient collection function and mechanical strength.However, the present invention The porous ceramic structure obtained by this method has less pressure loss, better collection function, and better mechanical strength than conventional structures.

The porous ceramic structure obtained in the present invention has a catalyst carrier,
Heat-resistant filters, chemical-resistant filters, molten metal filters,
Useful for applications such as gas diffusers and fluid mixers.

The structure obtained by the present invention (second invention) is particularly useful for collecting carbon fine particles contained in the exhaust gas of a diesel internal combustion engine.

[Brief explanation of the drawing]

FIG. 1(a) is a perspective view showing a foam filter obtained according to the present invention, FIG. 1(b) is a cross-sectional view of a main part showing the cross section of the filter of FIG. 1(a), and FIG. 2 is the same as that shown in FIG. FIGS. 3(a) and 3(b) are a plan view and a sectional view showing an example of a mold container portion used for explaining the present invention; FIG. ), (b) are a plan view and a cross-sectional view showing an example of a mold lid part provided for explanation of the present invention, FIG. 5 is a cross-sectional view showing a state in which FIG. 3 and FIG. 4 are combined, and FIG. FIG. 6 is a characteristic diagram for explaining the present invention in detail. Nippondenso Co., Ltd. Figure 1 (a) (b) Figure 2 Figure 3 (a) (b)

Claims (1)

[Claims] 1. When producing a porous ceramic structure by adhering a ceramic slurry to an organic polymer foam, drying and firing, the foam contains an organic polyisocyanate and an amine-based polyether polyol ( a) and non-amine polyether polyol (b) as a silicone foam stabilizer, 3
1. A method for producing a ceramic structure, characterized by using a polyurethane foam formed by mold foaming in the presence of a grade amine catalyst and a blowing agent. 2. The manufacturing method according to claim 1, wherein (a) is a polyoxyalkylene polyamine having a hydroxyl value of 10 to 70. 3. The method according to claim 1 or 2, wherein (b) is a polyoxyalkylene polyol having a terminal oxyethylene chain and having a hydroxyl value of 10 to 70. 4. The manufacturing method according to claim 1, 2 or 3, wherein the ratio of (a) and (b) is 5:95 to 70:30. 5. Claim 1, wherein the catalyst consists of a tertiary amine that promotes a resin-forming reaction and a tertiary amine that promotes a foaming reaction.
The manufacturing method according to any one of items 1 to 4. 6. The foam has a free foaming density of 0.02-0.04g
Packing rate of foam stock solution that gives /cm^3 is 120 ~
The manufacturing method according to any one of claims 1 to 5, which is a polyurethane foam obtained by injecting the polyurethane foam into a mold in an amount of 300%. 6. Inside the ceramic, a plurality of parallel columnar hollow holes are provided so as to form a lattice-like arrangement in a cross section perpendicular to the axis of the hollow holes, and one end of the columnar hollow hole is opened at one end surface of the ceramic. A method for manufacturing a porous ceramic structure in which the other end is sealed at the other end face of the ceramic, and adjacent columnar hollow holes open in opposite directions across the hollow hole walls arranged in a lattice pattern. , a mold container portion consisting of an end face and a side wall to which a columnar member is fixed for forming a group of columnar hollow holes opening in the same direction, and the other end face is open; and the other columnar hollow hole opening in the same direction. The cavity of the mold formed by engaging the mold lid to which the columnar members for forming the group are fixed has the same shape as the above-mentioned ceramic, and in the mold cavity, the organic polyisocyanate and the amine-based poly A step of mold-foaming the ether polyol (a) and the non-amine polyether polyol (b) in the presence of a silicone foam stabilizer, a tertiary amine catalyst, and a blowing agent to obtain a foam having the same shape as the ceramic; A method for producing a porous ceramic structure, comprising the steps of impregnating a foam obtained in the process with a ceramic slurry, drying and firing.