JPS61291467A - 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 fine particles contained in exhaust gas of a diesel internal combustion engine or as a catalyst carrier.

[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 foam having a three-dimensional network skeleton is foamed, the resulting organic compound foam is subjected to film removal treatment, impregnated with ceramic slurry, 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 (combustion) ) treatment 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 a long time, the cell skeleton will collapse. There is a need for a porous ceramic that does not require such membrane removal treatment or can produce a sufficient membrane removal effect with a short membrane removal treatment.

Means for Solving Problem U] According to the present invention, the polyurethane foam obtained using a specific catalyst can be used for the production of porous ceramics as described above,
It has been found that the method disclosed in JP-A-58-161962 is particularly useful.

That is, in the present invention, when a porous ceramic structure is produced by adhering a ceramic slurry to an organic polymer foam, drying and firing the foam, organic polyisocyanate and polyether polyol are used as part of the catalyst. , the general formula (wherein R1 and R2 are each an alkyl group having 1 to 4 carbon atoms, R1 and R2 are bonded to each other,
It may form a 3- to 6-membered heterocycle together with the nitrogen atom. R3 is an alkylene group. ) A method for manufacturing a ceramic structure characterized by using a polyurethane foam formed by mold foaming in the presence of a silicone foam stabilizer and a foaming agent using a carbon salt or formate of a polyamine (first invention) ; and 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 holes is provided with a hole on one end surface of the ceramic. Manufacture of a porous ceramic structure in which the columnar hollow holes are open and 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 method, the forming mold container part has an open end face consisting of an end face to which a columnar member is fixed and a side wall for forming a group of columnar hollow holes opening in the same direction, and the other columnar hollow opening in the same direction. The mold cavity formed by engaging the mold lid to which the columnar member for forming the hole group is fixed has the same shape as the above-mentioned ceramic, and in the mold cavity, the organic polyisocyanate and the polyether polyol are as part of the catalyst, using the general formula (wherein R1 and R2 each have 1 carbon number
It is a 4- to 4-membered alkyl group, and R1 and R2 may be bonded to each other to form a 3- to 6-membered heterocycle with the nitrogen atom. R3 is an alkylene group. ) using a carbonate or formate of a polyamine represented by the formula (2) and foaming it in a mold in the presence of a silicone foam stabilizer and a foaming agent to obtain a foam having the same shape as the ceramic, and a foam obtained in the above step. A method for producing a porous ceramic structure (second invention) comprising the steps of impregnating a porous ceramic structure with a ceramic slurry, drying it, and firing it.

In general formula (1), R1 and R2 have 1 to 4 carbon atoms
Examples of the alkyl group include straight-chain or branched alkyl groups such as methyl, ethyl, n- or iso-propyl, n- or iso-butyl. R1 and R2 are bonded to each other to form a group such as ethylene, n- or iso-propylene, tetramethylene, pentamethylene,
It may form a 3- to 6-membered heterocycle together with the nitrogen atom.

Among the above R1 and R2, a methyl group is preferred from the viewpoint of catalytic activity. The alkylene group that is R3 has 2 carbon atoms.
-12 alkylene groups Examples include linear or branched alkylene groups such as ethylene, n-propylene, tetramethylene, hexamethylene, 2-ethylhexylene, and decamethylene. Preferred are ethylene, n-propylene, and n-butylene groups from the viewpoint of catalytic activity.

Examples of the polyamine represented by the general formula (1) include the following compounds.

(1) Salts of dialkylaminoalkylamines and carbonic acid: Polyamines represented by (wherein R4 and R5 are each an alkyl group having 1 to 4 carbon atoms, and R3 is an alkylene group): For example, dimethylamine ethylamine , dimethylaminopropylamine, diethylaminepropylamine, dibutylaminoethylamine, dimethylaminooctylamine, dipropylaminopropylamine, etc.] and carbonic acid.

(2) Salt of heterocyclic aminoalkylamines and carbonic acid: (In the formula, A is an alkylene group having 2 to 8 carbon atoms, and R3 is an alkylene group having 2 to 12 carbon atoms.) Petrocyclic aminoalkylamines: e.g. 2-(1-aziridinyl)ethylamine, 4-(1-piperidinyl)-
2-hexylamine, etc.] and carbonic acid.Among the carbonates of polyamines, carbonates of polyamines such as dimethylaminopropylamine and dimethylaminoethylamine are particularly preferred.

In the salt of carbonic acid with polyamine, the molar ratio is usually 7
~1:1~4'', preferably 5~1:1~3. If the molar ratio is greater than 7:1, there will be problems with the foul odor of the free polyamine and toxicity to the human body due to amine vapor, and if the molar ratio is greater than 1:3, the tactile temperature sensing property will deteriorate. This salt can be easily obtained by a known method, for example, by contacting and stirring an aqueous solution of a polyamine with carbon dioxide gas or dry ice at room temperature or under cooling under normal or elevated pressure.

Conversely, it can also be obtained by mixing and stirring a polyamine in an aqueous carbonate solution. The polyamine carbonate obtained by the reaction is represented by the following general formula.

[In the formula, Rt, R2, and R3 are tertiary amines used together as a catalyst in the present invention in general formula (1),
A tertiary amine that promotes the resin formation reaction, a tertiary amine that promotes the foaming reaction, and especially a combination system of both are used.

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, and 1,8-diaza-bicyclo[5゜4 , O]Launsen-7, dimethylaminopropylamine, and organic acid salts thereof (other than formate). Preferred is triethylenediamine.

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, dimethylethanolamine, diethylethanolamine, and the like. Preferred is N-ethylmorpholine.

The amount of carbonate or formate of the polyamine represented by the general formula (1) is usually 0.2 to 2.0 parts, preferably 0.5 to 1.0 parts per 100 parts (by weight, the same applies hereinafter) of the polyol. .5
I'm at the club. 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, and if it is more than 2.0 parts, the surface skin of the molded foam will tend to form and the air permeability will deteriorate.

The amount of resin conversion catalyst used is usually 0.01 part to 0.2 part, preferably 0.02 to 0.1 part, per 100 parts of polyol. If it is less than 0.01 part, the resin formation reaction is slow and curing takes a long time. Moreover, 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 to 100 polyols.
The amount is 0.9 part, preferably 0.4 to 0.6 part. 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 0.9 parts, foaming becomes too fast, the foam cells become fine, and air permeability deteriorates.

The ratio of the carbonate or formate of the polyamine of general formula (1), the resin forming catalyst, and the foaming catalyst is usually 40 to 75:1 to 5:2.
5-60. Preferably 50-65: 1-2: 35-4
It is 5. The total amount of the three is usually 1.0 to 3.0 parts per 100 parts of polyol.

Examples of the polyether polyol used in the present invention include compounds having a structure in which an alkylene oxide is added to a polyfunctional compound containing an active hydrogen atom, such as a polyhydric alcohol, a polyhydric phenol, a polycarboxylic acid, or an amine compound. The polyhydric alcohols mentioned above include dihydric alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and neopentyl glycol; trihydric alcohols such as glycerin and trimethylolpurpan; Tetrahydric or higher alcohols such as erythritol, sorbitol, and sucrose; Polyhydric phenols include polyhydric phenols such as pyrogallol and hydroquinone, as well as bisphenol A.
Bisphenols such as, novolac resins having two or more phenolic hydroxyl groups, intermediates of resol resins, etc.;
Examples of polycarboxylic acids include aliphatic polycarboxylic acids such as succinic acid and adipic acid, and aromatic polycarboxylic acids such as phthalic acid, terefucolic acid and trimellitic acid. Examples of amine compounds include 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 N-aminoethylpiperazine; and monoethanolamine, jetanolamine, Examples include alkanolamines such as triethanolamine.

Two or more kinds of the above-mentioned active hydrogen atom-containing compounds can also be used. Examples of the alkylene oxide to be added to the active hydrogen atom-containing compound 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 other alkylene oxides (
butylene oxide, tetrahydrofuran, styrene oxide, etc.) may be used in combination. From the viewpoint of reactivity, a combination system of propylene oxide and ethylene oxide (usually in a weight ratio of 70:30 to 95:5) is preferable.
In particular, the ratio is 80:20 to 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.

The OH number of the polyether polyol 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, there will be a lot of skin and cell membranes on the mold surface, resulting in a foam with poor air permeability. Become. The (average) number of functional groups is usually 2 to 8, preferably 2 to 4.

Among polyether polyols, those having an oxyethylene chain at the end are preferable [chip type, balanced type,
Random chip type (having random polyoxyethylene/oxypropylene chains inside)]. The terminal oxyethylene group content is usually 5% (weight%, the same applies hereinafter) or more, preferably 5 to 30%, more preferably 10 to 2%.
It is 0%. If the oxyethylene chain content is less than 5%, curing immediately before the end of foaming will be insufficient and the foam will collapse. The total oxyethylene group content is usually 5 to 50%, preferably 10 to 30%.

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 (M, DI)) , naphthylene diisocyanate,
xylylene diisocyanate, etc.] and mixtures thereof. Among these, aromatic diisocyanates are preferred, and particularly preferred are TDI,
It is MDI. These polyisocyanates include crude polyisocyanates, such as crude TDI, crude MDI, crude diaminodiphenylmethane (a condensation product of formaldehyde and an aromatic amine or a mixture thereof), and a small amount (for example, 5 to 20% by weight) of trifunctional or higher functional It can also be used as a phosgene compound (mixture with polyamine): polyallyl polyisocyanate (PAPI)]. Alternatively, a free isocyanate-containing prepolymer obtained by reacting a modified polyisocyanate such as liquefied MDI (carbodiimide modification, trihydrocarbyl phosphate modification, etc.) or an excess polyisocyanate (TDI, MDI, or a modified product thereof) with a polyol. or they can be used in combination (for example, a modified polyisocyanate and a prepolymer are used in combination).The polyol used for producing the above prepolymer usually has an equivalent weight of 30 to 200, such as ethylene glycol and propylene glycol. , glycols such as diethylene glycol and dipropylene glycol; triols such as trimethylolpropane and glycerin; high-functional polyols such as pentaerythritol and sorbitol; and alkylene oxide (ethylene oxide and/or propylene oxide) adducts of these. Among these, preferred are those having 2 to 3 functional groups.The content of free isocyanate groups in the modified polyisocyanate and prepolymer is usually 10 to 30%, preferably 15%.
-30%, particularly preferably 20-30%. Among organic polyisocyanates, TDI and crude MD are preferred.
A mixture of I (weight ratio e.g. 95-5:30-
70, preferably 90:10 to 50:50).

As the blowing agent, water and/or a halogen-substituted aliphatic hydrocarbon blowing agent (fluorocarbons such as trichloromonofluoromethane) can be used. Preferably, it is washed with 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 49/cIII. Free foam density is 0.02 g
If it is less than /crt1, when it is made into mold form,
This causes cell roughness of the foam, and if it is higher than 0.049/crd, a strong surface skin will increase 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 30%. That is, an amount 1.2 to 3 times the minimum required amount of foam stock solution (injection amount in the case of free foaming) calculated from the internal volume of the mold is injected. If the packing rate is less than i9Q%, the mold 7 will suffer from cell roughness and cell 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 air permeability, and rapid foaming, and too much foaming pressure, which will significantly reduce workability during mold injection. . Further, if necessary, pigments, fillers, flame retardants, thixotropic agents, etc. can 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 7
0 to 1201, preferably 80 to iio.

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.

The alkali used for alkaline aqueous solution treatment is ＼aOH
, KOH. The concentration of the aqueous solution is usually 20-50
It's %. The alkaline aqueous solution treatment can be carried out using conventional methods and conditions. For example, the mold form is 80-90
Soaked in 30% alkaline aqueous solution at °C for 15-20 hours,
Remove membrane.

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
4: Must be 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
After reducing the pressure to g, a mixed gas of 7% propane and 93% oxygen was added to bring the pressure to 760 mHg, and the mixture was burned to remove the film.

In the present invention, a conventional method can be used to produce a porous ceramic structure using a polyurethane foam foamed in the presence of a carbonate or formate of a tertiary amine represented by general formula (1). , for example, JP-A-5
5-24585, JP 55-111817, JP 58-161962, JP 58-91048,
Examples include those described in JP-A-58-151382.

The raw material of the ceramic slurry used for impregnation is M (JO1A1203, S
A mixed powder containing iO2, or a synthetic cordierite powder obtained by heating the above mixed powder to make cordierite ceramics and pulverizing this, or a mixture of both with a binder such as methylcellulose, ethylcellulose, polyvinyl alcohol, or polyvinyl butyral, Although it is preferable to use water-added ceramic raw materials, the ceramic raw materials are 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 triangle, a square, a regular hexagon, etc., but is not necessarily limited to these shapes. Further, the size and number of the hollow holes, the thickness of the hollow hole wall, and the thickness of the hollow hole sealing part 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 lattice pattern with approximately the same cross section and length as other hollow holes opening in the same direction at appropriate intervals. 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 is approximately the same shape as the porous ceramic that is the target manufactured article, and is necessarily 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 may be performed by assembling the molds and then injecting the foam stock solution.The foam stock solution is injected into the mold container, the mold lid is immediately assembled, and the excess foam is foamed inside the mold. The 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. In addition, the inside of the molded body may be coated with a suitable mold release agent or surface treated with Teflon treatment, etc., so that the organic compound can be easily removed from the molded body after foaming. is desirable.

[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.

Polyol: A polyether polyol with a molecular fi of 5000 obtained by addition polymerizing 4258 parts of propylene oxide to 92 parts of glycevin and 650 parts of ethylene oxide.

Catalyst ■ Nitriethylenediamine catalyst ■: N-ethylmorpholine catalyst ■ Formate salt of dimethylaminopropylamine Foaming agent ■ Nitrichloromonofluoromethane foam stabilizer ■: Silicone foam stabilizer B-5246 [manufactured by Goldschmidt] Isocyanate I: TDI-80 and Crude MDI
Isocyanate blended at a ratio of 80:20.

Foam production example 1 4.0 parts of water per 100 parts of polyol I, catalyst o
, part i, 0.6 parts of catalyst ■, 10.9 parts of catalyst I, 10.75 parts of foam stabilizer, and 15 parts of blowing agent I, added 45 parts of isocyanate, and heated at 1000 RP.
) After stirring and mixing for 10 seconds at speed I, the mold temperature was 50'.
The mixture was poured into a mold (30 x 30 x 5 cm, manufactured by A, 2) having a vent hole of 1,51!1171φ adjusted to C, the lid was closed, and foaming was performed within the mold. After 3 minutes have passed after the completion of foaming, heat in an oven at 100°C for 30~45 minutes.
Cured for minutes.

The obtained foam was examined for the amount of surface skin cell film, air permeability, and general mechanical properties using the following evaluation methods.

(Form evaluation method) Area of A0 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 better the breathability of the foam.

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 when used as a filter, the pressure loss is small and the foam is excellent.

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

The shorter the processing time, the easier it is to obtain a skinless mold form with a complete surface skin and fewer cell membranes.

D1 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 judged as cell collapse.

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

Foam Production Examples 2 to 8 The same procedure as in Example 1 was carried out except that the amount of catalyst (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 (AJ! 020)
3) 100 parts of a formulation of talc kaolin and faeialite (ferroolivine) formulated to have a chemical composition of 32% ferrous oxide (FeO) and 60 parts water, One part of polyvinyl alcohol as a binder and one 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 (A1203
) 35% years old, nihi'? A mixture of talc, kaolin, and aluminum hydroxide blended to have a chemical composition of 14% Cunesia (MgO) 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 having 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 have their ends 22 closed and communicate with each other via partition walls 21 located between the hollow holes 20. This partition wall 21 has a two-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 211 has become extremely 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 16 are provided on the side periphery of the flat plate.
7 is provided.

A mold is created by combining the mold container portion 1 and the mold lid portion 10 having such a configuration. 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) Manufacture of foam molded article Now, a specific method for manufacturing a foam molded article using the mold having the above configuration will be described.

(a) Polyol 1 described in Foam Production Example 1 above
ioo parts: 4.0 parts of water, 0.6 parts of catalyst II,
Catalyst I [IO, 9 parts, Catalyst I O, 10 parts, Foam stabilizer IO
, 75 parts, blowing agent I 15 parts, isocyanate I
Add 25 parts and mix by stirring at a speed of 11000 pp for 8 seconds. This mixture is then applied to the mold shown in FIG.
Inject through every other communicating hole 16 at a mold temperature of 50'C).

Note that at this time, the air inside the mold flows through the remaining communication holes 1.
6 to facilitate the injection of the raw material liquid. In addition, when injecting the urethane foam, first inject the undiluted solution of urethane foam into the mold container part 1, and then
It was also possible to create the mold by inserting a urethane foam into the mold and discharging the air and excess urethane foam from the mold lid 10 through a number of communication holes 16 provided in the mold lid 10.

Next, foaming is performed in the cavity 18, and the temperature is 15°C at 80'C.
Heated and cured 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 product obtained as described above, the foam stabilizer in the raw material liquid, the wax 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 cover 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# or less (1 to 20#) as in the foam molded product shown in FIG. space;
(see Figure 5), the cells of the foam collapse, but the surface tension of the wax-based mold release agent applied to the inner surface of the mold prevents this collapse, which greatly contributes to the molding of skinless foam. . 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.

Thus, it has a cylindrical shape with an outer diameter of 120 m and a length of 150 m, and has a square hollow hole (numeral 20 in Fig. 1) with - sides of 5 m and a partition wall (numeral 21 in Fig. 1) with a thickness of 3 m, 10
A foam molded body with a vent size of ˜80 mesh was obtained.

(b) Here, an experimental example will be explained to demonstrate the superiority of the present invention. All test products had the structure shown in Figures 1 (a) and (b), with a diameter of 127 traces, a length of 110 mm, a partition wall thickness of 3 cocoons, a ventilation hole size of 60 to 70 mesh, and a hollow hole size. has the dimensions of a square with 4# corners. 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 with 30% Na kept at a temperature of 80 to 90°C.
The skin (thin film) formed on each skeleton was removed by immersion in an OH 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 addition, in the above-mentioned method for producing a foam molded article, the mold release agent used was URT-351 (trade name, manufactured by Bond Wax Co., Ltd.), but it changed from the same phase to a liquid phase at a temperature of 80°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 thus obtained 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 hollow hole wall 21. Further, the sealing portion 22 of the hollow hole is made integrally with the hollow hole wall 21.

By the above method, the porous ceramic has a cylindrical shape with an outer diameter of 120 m and a length of 150 m, has a square hollow hole with sides of 5 m, a hollow hole wall with a thickness of 3 #, and a roughness of #40. A structure was manufactured.

Using this porous ceramic, a test was conducted on the collection efficiency of carbon particles. Under the conditions of displacement 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 0.35 g/mile, indicating a high collection rate. 87.5% was obtained. The pressure drop was 2 cmH2O under the condition that air was passed through at 1 Td/min.

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 cmHz O (1 Tri/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.

The polyurethane foam formed by mold foaming using a catalyst consisting of a carbonate or formate of a polyamine represented by the general formula (1) used in the present invention has a higher cell membrane and surface skin than conventional polyurethane foams. It has good air permeability, has a thin cell skeleton, and the cells are aligned, so there is little pressure loss. (processing, etc.) takes a significantly shorter time (in some cases, it can be omitted).

In conventional foams, even when treated with an alkaline aqueous solution, the surface skin and cell membrane cannot be sufficiently removed, 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 and a foam that did not have a collection function as a filter, and had 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,
It is useful for applications such as heat-resistant filters, chemical-resistant filters, molten metal filters, 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 is made of an organic polyisocyanate and a polyether polyol as a catalyst. Some of the general formulas include mathematical formulas, chemical formulas, and tables. may form a 3- to 6-membered heterocycle with R_3 is an alkylene group), and molded in the presence of a silicone foam stabilizer and a blowing agent. A method for manufacturing a ceramic structure characterized by using expanded polyurethane foam. 2. The manufacturing method according to claim 1, wherein the polyamine is dimethylaminopropylamine. 3. 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 claim 1 or 2, which is a polyurethane foam obtained by injecting the polyurethane foam into a mold in an amount of 300%. 4. 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 polyol are catalyzed. As part of the general formula, there are mathematical formulas, chemical formulas, tables, etc.▼(1) Using a carbonate or formate of a polyamine represented by the formula (which may form a 3- to 6-membered heterocycle with the atom; R_3 is an alkylene group), in the presence of a silicone foam stabilizer and a blowing agent. A porous ceramic structure comprising a step of mold foaming to obtain a foam having the same shape as the ceramic, and a step of impregnating the foam obtained in the step with a ceramic slurry, drying and firing. Manufacturing method.