JP2003238649A - Method for manufacturing open cell porous product made of epoxy resin and pressure casting mold for ceramics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an open cell porous product made of an epoxy resin which hardly causes epoxy resin particles dispersed in an emulsion slurry for forming the open cell porous product made of an epoxy resin to remain in the pores of the open cell porous product, hardly causing clogging of the pores, and always exhibits well-balanced air-permeability, and a pressure casting mold for ceramics obtained using the same. <P>SOLUTION: The method for manufacturing an open cell porous product made of an epoxy resin comprises a step for preparing an emulsion slurry for forming an open cell porous product made of an epoxy resin, a step for preparing a water-impervious mold for pouring the emulsion slurry thereinto, a step for pouring the emulsion slurry into the water-impervious mold, a step for hardening the emulsion slurry to form the open cell porous product made of an epoxy resin, and a step for washing the formed open cell porous product made of an epoxy resin, where the water-impervious mold is maintained at a specified temperature in the step for preparing the water-impervious mold. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a continuous porous body made of epoxy resin and a pressure casting mold for ceramics.

[0002]

2. Description of the Related Art Sintering of metal powder has hitherto been used as a means for producing a continuous porous body used for a filtering material, an air diffusing material, a molding material, etc.
Sintering of thermoplastic resin powder, sintering of inorganic powder, hydration hardening of cements, mixed press molding of thermoplastic resin and filler,
Alternatively, stamping, a method of curing a resin liquid containing a pore-forming agent and removing the pore-forming agent by dissolution extraction or evaporation, use of a foaming agent, and after curing and polymerizing a W / O type emulsion like a water-containing polyester resin Many methods have been proposed, such as a method of evaporating water. However, in the case of producing a continuous porous body by these methods, the shape and size of the product are significantly limited, often a high temperature heat treatment or a high pressure press is required, or the manufacturing process is complicated. was there. Further, in these methods, it is very difficult to control the most important pore diameter when the continuous porous body is used as a filter material or an air diffuser. As a method of solving these problems and producing a large continuous porous body having a complicated shape with good dimensions and having a desired pore diameter, a mixture containing an epoxy resin, a curing agent, a filler and water is stirred. Then, an emulsion slurry is obtained, and the emulsion is cured in a water-containing state so that the water portion becomes pores. For example, JP-A-50-116598
In the publication, an O / W type emulsion slurry comprising a mixture of a glycidyl epoxy resin, a polymerized fatty acid polyamide curing agent, a filler and water is prepared, and this emulsion slurry is cast into an impermeable mold and cured in a water-containing state. After that, the intended purpose is achieved by dehydration. According to this method, it is possible to form a large continuous porous body of complicated shape with high dimensional accuracy, the particle size of the filler, the amount of the reactive diluent, the epoxy resin, the curing agent, the filler, the mixing ratio of water, etc. The pore size can be controlled by changing However, the continuous porous body obtained by this method is deviated to a very fine portion having a pore diameter of 1.5 μm or less, and has poor practicability as a filtering material, an air diffusing material, and a molding material.

A method for solving this problem is to use monomeric fatty acid and ethyleneamine [H ₂ N- (CH ₂ -CH ₂ -NH) _n
-H (where n is 3 to 5)], a mixture of an amide compound obtained by the reaction with a polymerized fatty acid and a polymerized fatty acid polyamide obtained by reacting the above ethyleneamine, or the monomer fatty acid and the polymerized fatty acid. A mixed reaction product obtained by mixing and reacting the ethyleneamine is used as a curing agent, and a mixture containing a bisphenol type epoxy resin, the curing agent, a filler and water is strongly stirred to obtain an emulsion slurry. A method for producing a continuous porous body, which comprises casting in a water-impermeable mold, curing in a water-containing state, and then dehydrating (Japanese Patent Laid-Open No. 59-71339). By this method, a continuous porous body having an average pore size of 0.5 to 10 μm, preferably 0.5 to 5 μm
It becomes possible to mold a large-scaled and complicated-shaped continuous porous body having an average pore diameter of 1 with high dimensional accuracy, and particularly preferably to manufacture with a desired average pore diameter between 1.5 and 5 μm with high accuracy. It was Further, in Japanese Patent Laid-Open No. 63-75044, an emulsion slurry is obtained from a mixture of a glycidyl epoxy resin, a polyamide curing agent, a modified polyamine curing agent and / or an amine curing agent, a filler and water, which is impermeable to water. There is also disclosed a method for producing a continuous porous body having pores in the range of 0.2 to 10 μm by casting in a solid state and curing in a water-containing state.

[0004]

However, in the conventional method, the temperature of the water-impermeable mold into which the emulsion slurry is poured is kept at room temperature. Therefore, the heat of the precipitated resin particles from the emulsion slurry during curing of the epoxy resin continuous porous body is increased. The movement becomes poor, the precipitated resin does not integrate with the filler, and the dispersed resin particles are likely to remain in the pores of the epoxy resin continuous porous body. Therefore, the resin particles cured while being dispersed in the pores cause the pores to be clogged, deteriorating the air permeability of the continuous porous body made of an epoxy resin, leading to a shortened life.

The object of the present invention is to prevent epoxy resin particles dispersed in an emulsion slurry for forming a continuous porous body made of epoxy resin from remaining in the pores of the continuous porous body and to prevent clogging of the pores at all times. It is an object of the present invention to provide a method for producing a continuous porous body made of an epoxy resin having well-balanced air permeability, and a pressure casting mold for ceramics using the same.

[0006]

Means for Solving the Problems The present invention comprises a step of preparing an emulsion slurry for forming an epoxy resin continuous porous body, a step of preparing a water-impermeable mold into which the emulsion slurry is poured, and the emulsion in the water-impermeable mold. A method for producing an epoxy resin continuous porous body, comprising a step of pouring a slurry, a step of curing the emulsion slurry to form an epoxy resin continuous porous body, and a step of washing the formed epoxy resin continuous porous body. In the step of preparing the impermeable mold, the temperature of the impermeable mold is maintained at a predetermined temperature. By heating the impermeable mold that pours the emulsion slurry for forming the continuous porous body made of epoxy resin, the resin precipitated from the continuous phase is integrated with the filler during curing of the emulsion slurry, and floating resin particles remain. It becomes difficult to do. Therefore, the pores in the continuous porous body obtained by curing the emulsion slurry are unlikely to be clogged, and it is possible to always obtain a well-balanced air permeability.

In a preferred embodiment of the present invention, the temperature of the impermeable mold is 25 to 25 in the step of preparing the impermeable mold.
It should be 40 ° C. Temperature of impermeable mold is 25 ℃
When it is below, when the emulsion slurry is hardened, the reaction heat is taken away, leading to poor hardening. On the other hand, when the temperature of the impermeable mold is 40 ° C. or higher, the strength of the epoxy resin continuous porous body decreases. Therefore, by setting the temperature of the preferable impermeable mold to 25 to 40 ° C., stable hardening of the emulsion slurry can be obtained, and clogging of continuous pores after hardening is unlikely to occur.

Further, the present invention is a ceramics pressure casting mold using the epoxy resin continuous porous body formed by the method for producing an epoxy resin continuous porous body. Pressure casting of ceramics means the inside of the epoxy resin continuous porous body,
Alternatively, it is characterized by forming a hollow passage for circumscribing water and / or air, casting a slurry composed of a base particle such as clay and a solvent such as water into a porous mold, and applying pressure to the slurry. As a result, the continuous porous body made of epoxy resin absorbs the solvent and the slurry is inked. After that, by introducing air into the hollow passages uniformly arranged in the epoxy resin continuous porous body, the solvent and air were exuded uniformly from the surface of the epoxy resin continuous porous body (the inking surface), and the ink was infiltrated. This is a method of releasing the molded product. When used as a mold for pressure-cast molding of ceramics, variations in breathability cause defects such as mold release defects in the molded body of ceramics. Does not adversely affect.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A continuous porous body made of epoxy resin is
A mixture containing an epoxy resin, a curing agent, a filler, water, etc. is stirred to obtain an emulsion slurry, the temperature of the impermeable mold is room temperature, the emulsion slurry is cast, and the epoxy resin continuous porous body raw material is in a water-containing state. It means that it is cured as it is.

The raw materials for the epoxy resin continuous porous body will be described below. It is convenient to use an epoxy resin that is liquid at room temperature and has a low viscosity as the epoxy resin, and it is preferable to use a bisphenol type such as bisphenol A type, bisphenol F type, or bisphenol AD type. Epoxy resin can be used.

As the curing agent, a polyamide type, a polyamine type, a modified polyamine type, or a mixture thereof is suitable for preparing an emulsion slurry having a low viscosity. The particularly suitable among them, a curing agent of polyamide, monomeric fatty acid and ethyleneamine _{[H 2 N- (CH 2 -CH 2} -NH) n -H
(Where n is 3 to 5)], a mixture of an amide compound obtained by the reaction with a polymerized fatty acid and a polymerized fatty acid polyamide obtained by the reaction of the above ethyleneamine, or the monomer fatty acid, the polymerized fatty acid and the ethylene. An example is a reaction mixture obtained by mixing and reacting an amine.

The filler is not particularly limited, but a material having a material capable of being bonded with an epoxy resin and having a controllable particle size is preferable, and examples thereof include silica stone powder or silica sand powder. In addition, when it is desirable that the cured product is lightweight, organic powder or microballoons can be used.

Further, as a raw material of the emulsion slurry in the present invention, allyl glycidyl ether, butyl glycidyl ether, styrene oxide, phenyl glycidyl ether, cresyl glycidyl ether, ethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6 -Reactive diluents such as hexanediol glycidyl ether and trimethylolpropane triglycidyl ether, hardening accelerators such as benzyldimethylamine and 2,4,6-tris (dimethylaminomethyl) phenol, potassium chloride, sodium chloride, Zinc chloride, calcium chloride, barium chloride, titanium chloride, iron chloride, nickel chloride, magnesium chloride, aluminum sulfate, zinc sulfate, ammonium ammonium sulfate, sulfuric acid Rumi bromide potassium, potassium sulfate, cobalt sulfate, iron sulfate, copper sulfate, sodium sulfate,
Soluble inorganic salts such as nickel sulfate, magnesium sulfate, manganese sulfate, sodium hydroxide, potassium hydroxide and calcium hydroxide can also be added.

Next, a method for forming a continuous porous body made of epoxy resin will be described. It is preferable to classify each raw material that constitutes the emulsion slurry into three phases: resin (including epoxy resin and curing agent, reactive diluent and curing accelerator when added), filler, and water. The volume ratio of the whole emulsion slurry is 100
Volume%, resin 8-45% by volume, filler 20-6
5% by volume and 20-60% by volume of water.

The resin, filler, and water are stirred by a high-speed stirrer, a reciprocating rotary stirrer, etc., and the obtained emulsion slurry is cast into a water-impermeable mold and hardened in a water-containing state to make it water-impermeable. Release from the mold. Regarding agitation, bubbles are prevented from being entrained, and resins, fillers and the like have high viscosity, so that they are difficult to mix. Therefore, from the viewpoint of obtaining a uniform emulsion slurry, a strong stirring force is required rather than a fast rotation, and therefore, a preferable stirrer is a reciprocating rotary stirrer.

In the epoxy resin continuous porous body obtained above, the resin is adhered to the filler during the process of hardening the emulsion slurry and water forms pores, but the cohesive force of the emulsion slurry is increased. A weak resin does not adhere to the filler and the resin component is formed as it is. When the curing is completed, the resin component exists in the pores in a state of being suspended or adsorbed, so that the continuous porous body made of epoxy resin is washed with water / or air.

As the method for heating the impermeable mold, there are a vapor phase method for heating in a temperature-controllable room (such as an incubator) and a solid phase method for heating with a heating sheet, or heating in a liquid. Although there is a liquid phase method of heating, the most preferable heating method is a gas phase method capable of obtaining stable heating.

The temperature at which the impermeable mold is heated is preferably 25 to 40 ° C., more preferably, the curing of the epoxy resin continuous porous material is accelerated, and stable air permeability is always maintained. It is possible to be 30 to 35 ° C.

As one example of application of the continuous porous body made of epoxy resin in the present invention, application to a pressure casting mold of ceramics can be mentioned. What is pressure casting of ceramics? Slurry consisting of base particles such as clay and a solvent such as water is cast into a porous mold, and pressure is applied to the slurry so that the mold absorbs the solvent and solidifies the slurry. There is a method of releasing the solidified molded product from the mold. This molding method includes solid casting in which the mold absorbs the solvent from both sides of the molded product, and discharge of the excess slurry after the mold has absorbed the solvent from one side of the molded product and has a predetermined thickness. Although there is mud pouring, the pressure pouring mold of ceramics according to the present invention can be applied to any of the methods.

As a preferred embodiment of this pressure casting mold, it is possible to provide ventilation means for releasing the molded product from the mold. This is because when the molded product is removed from the mold, the solvent and air from the slurry absorbed by the mold by applying pressure from the back surface of the mold (the surface on the opposite side of the inking surface) to the molded surface and the molded product. It is provided for exuding between the two and smooth release. A preferable example of the ventilation means is to provide a hollow passage inside the continuous porous body made of epoxy resin. This hollow path is the surface of epoxy resin continuous porous body
The solvent and air are uniformly exuded from the mold, and the hollow passage is connected to one or more passages leading to the outside of the mold. At the time of releasing the mold, if pressurized air is blown through a hollow passage from a passage leading to the outside of the mold, the solvent and the air can be exuded between the wall of the mold and the molded product. However, if the air permeability of the continuous porous body made of epoxy resin is varied, the mold release is not smoothly performed, and a defect occurs in the molded body. Therefore, stable air permeability without variation is required.

[0021]

[Examples] Materials prepared in the mixing ratios shown in Table 1 were placed in a stainless steel container without a lid and vigorously stirred at room temperature for 10 minutes to obtain a uniform emulsion slurry. This emulsion slurry is applied to a water-impermeable mold (the shape is a rectangular parallelepiped of 200 × 300 × 20 mm, a tube is attached to the hollow path portion, and a vinyl chloride plate surrounds all four sides) at a temperature of 20.0 ° C. Casting, covering so that water does not evaporate,
It was left to stand in a room at 30 ° C. for 48 hours to cure in a water-containing state, the tube was removed, and the cured product was demolded. After that, as shown in FIG. 1, the hollow passage entrance 2 was closed in the epoxy resin continuous pore porous body 1, and the hollow road surface and the side surface were sealed with the sealing epoxy resin 3. Although not shown, all hollow passages provided inside the porous body are connected to each other, and each hollow passage is connected to the outside of the mold and connected to a pipe 4 for feeding air at the time of mold release. , This is test body 1
And

Similarly, as shown in Table 2, the temperature of the impermeable mold was set to 25.0 ° C., 30.0 ° C. and 3 ° C. according to the above procedure.
Change to 5.0 ℃, 40.0 ℃, 50.0 ℃,
Test body 2, test body 3, test body 4, test body 5, respectively
The test body 6 was used.

[Table 1]

[Table 2]

(Measurement of Aeration Rate) Next, the test bodies 1 to 6 formed in the examples were washed several times, and then the ventilation rate was measured. The measurement results are shown in Table 3. The procedure of measuring the air flow rate will be described below. 1. The water pressure and air pressure injected into 4 of FIG. 1 is 0.25M.
It is Pa. 2. From 4 in Fig. 1, while maintaining a water pressure of 0.25 MPa, 5
Water for minutes. After passing water for 3.5 minutes, the air pressure is 0.25 MPa from 4 in Fig. 1.
Aeration for 7 minutes. 4. The above procedure of 2 and 3 is set as one cycle, and washing is repeated several times. 5. After washing several times, the flow meter is relayed to 4 in FIG. 1 and the air flow rate (air flow resistance) after one minute of air flow is measured while maintaining the air pressure at 0.25 MPa.

(Measurement of Average Pore Diameter) Next, the average pore diameters of the test bodies 1 to 6 formed in the examples were measured. The measurement results are shown in Table 3. The measuring method is as follows:
Make a sample shredded into corners, and put mercury under pressure into the epoxy resin continuous porous body in the measuring instrument,
A Porosizer 9310 (manufactured by Shimadzu Corporation), which is a mercury press-in method characterized by measuring pore diameter, was used.

(Bending Strength Measurement) Next, in the same manner as in the example, a continuous porous body made of epoxy resin (shape 15 × 15)
Bending strength of the continuous porous body made of epoxy resin was measured under the following conditions and formula using a bending strength measuring machine (Autograph manufactured by Shimadzu Corporation). The test results are shown in Table 3. (Bending strength measurement conditions) 1. LOAD CELL ... (B) 2. RANGE ... (maximum load 500N) 3. CHART SPEED ... 100 mm / min 4. CROSSHEED SPEED ... 2.5mm / m
in 5. Distance between fulcrums ... 100 mm The above five items are conditions. (Bending strength calculation formula) St = 3Pl / 2ab ² St ... Bending strength (MPa) P ... Breaking load (N) l ... Distance between fulcrums (cm) a ... Sample width (cm) b ... Sample thickness (cm)

[Table 3]

From the above test results, regarding the ventilation amount,
As shown in Table 3 and FIG. 2, the air flow rate is increasing. Further, in the relationship between the temperature of the mold and the air flow rate, it is 25 to 35
It can be said that the first-stage stability region is at 0 ° C and the second-stage stability region is at 40 to 50 ° C. Regarding the average pore diameter, as shown in Table 3 and FIG. 3, it is relatively stable at a temperature of 20 to 35 ° C. However, when the temperature is 35 ° C. or higher, the temperature tends to increase remarkably. Regarding the bending strength of the continuous porous body made of epoxy resin, as shown in Table 3 and FIG. 4, as the temperature rises, the strength also increases, but the temperature tends to decrease at around 35 ° C. Judging from each test result comprehensively,
A preferable temperature range for heating the impermeable mold is 30 to 35.
It can be said to be ° C.

[0027]

According to the present invention, by heating a water-impermeable mold into which an emulsion slurry for forming an epoxy resin continuous porous body is heated, an epoxy resin continuous porous body always having well-balanced air permeability is obtained. Can be manufactured. Further, by using the continuous porous body made of the epoxy resin obtained in the above-mentioned production for a pressure casting mold of a ceramics, a pressure casting mold which does not adversely affect the molded product such as mold release defect can be realized.

[Brief description of drawings]

FIG. 1 is an overall view (cross-sectional view) showing a test body used in an example of the present invention.

FIG. 2 is a diagram showing the relationship between the impermeable mold temperature of the present invention and the air flow rate of an epoxy resin continuous porous body.

FIG. 3 is a diagram showing the relationship between the water-impermeable mold temperature of the present invention and the average pore diameter of an epoxy resin continuous porous body.

FIG. 4 is a diagram showing the relationship between the impermeable mold temperature of the present invention and the flexural strength of an epoxy resin continuous porous body.

[Explanation of symbols]

1 ... Epoxy resin continuous porous body 2 ... Hollow path 3 ... Epoxy resin for sealing 4 ... Air pipe

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Claims (3)

[Claims] 1. A step of preparing an emulsion slurry for forming an epoxy resin continuous porous body, a step of preparing an impermeable mold into which the emulsion slurry is poured, a step of pouring the emulsion slurry into an impermeable mold, and the emulsion slurry A method for producing an epoxy resin continuous porous body comprising a step of curing the epoxy resin continuous porous body, and a step of washing the formed epoxy resin continuous porous body, wherein the impermeable mold is prepared. In the step of, the temperature of the impermeable mold is maintained at a predetermined temperature, the method for producing a continuous porous body made of epoxy resin. 2. The method for producing an epoxy resin continuous porous body according to claim 1, wherein the predetermined temperature is 25 to 40 ° C. 3. A pressure casting mold of a ceramics using the continuous porous body made of epoxy resin formed by the method for producing a continuous porous body made of epoxy resin according to claim 1.