JP2002212306A - Method for agitating mixture for forming open-cell porous material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for agitating to obtain a mixture for forming a uniform open-cell porous material by agitating and dispersing a mixture consisting of a compound such as an epoxy, etc., a filler and water in a short time in producing the open-cell porous material made from a resin used as a mold for a slurry molding. SOLUTION: This method for agitating to obtain a mixture for forming a uniform open-cell porous material containing at least the epoxy compound, a curing agent, the filler and water is provided by agitating the above mixture for forming a uniform continuous pore porous material with a reciprocating rotary agitator having a reversing function not a single direction rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for stirring a mixture for forming a continuous porous material containing at least an epoxy compound, a curing agent, a filler, and water.

[0002]

2. Description of the Related Art As a mold used for casting of ceramics, a gypsum mold or a slurry casting mold having a continuous porous porous body made of a resin having a water absorbing property (hereinafter referred to as a resin casting mold) is generally known. However, in recent years, pressure molding using a resin casting mold having a short molding cycle time is becoming mainstream. The mold used here is more expensive than the gypsum mold, but the price difference is compensated for by the multiple production (extremely long mold life) and by obtaining a homogeneous product. In other words, it is clear that the more homogeneous products are produced, the more efficient the production becomes. Multiple production of a homogeneous product in a resin casting mold is performed by uniformly mixing and dispersing a compound such as epoxy, filler, and water, and then curing a mixture for forming a continuous pore porous body, which is made of resin. It depends on the continuous porous material. Conventionally, a conventional rotary stirrer for rotating a propeller-type or screw-type blade or a homogenizer having a fixed outer blade having a window and a rotating inner blade has been used for mixing the mixture for forming a continuous porous material.

The state of stirring using a conventional stirring device will be described with reference to the drawings. FIG. 5 shows a stirring blade used in a general rotary stirrer.
The blade 3 is attached. FIG. 6 is a view showing a mixing state by a general propeller type rotary stirrer. In the stirring tank 1, the propeller blades 6 attached to the rotating shaft 2
Is a specific liquid agitation direction 7, so that the rotating flow rotates from the axis of the stirring blade to near the tip at almost the same speed as the rotation speed of the blade, and the centrifugal force raises the liquid level on the tank wall side. ,
The shaft part is lowered and rotating while keeping balance with the centrifugal force.

[0004]

However, in such a flow state, only the rotational flow is generated, and almost no radial or axial flow occurs, and the rotary stirrer can only rotate the contents in a fixed direction. Although there is no problem in mixing hydrophilic liquids, it is difficult to uniformly disperse solids in the liquid or to uniformly mix hydrophilic liquid and hydrophobic liquid. Specifically, in a mixture for forming a continuous porous material in which a filler and water are mixed with a compound such as an epoxy, the filler is hard to disperse throughout the mixture only by performing a rotating flow operation together with the resin, and it takes time to form an emulsion. There was a problem of cost.

Further, a homogenizer having a fixed outer blade and a rotating inner blade is capable of discharging the agitated material from the window of the outer blade by centrifugal force caused by the rotation of the inner blade and taking in the mixture between the outer blade and the inner blade from below. It is effective for mixing hydrophilic and hydrophobic liquids, i.e., emulsification and emulsion formation. The incorporation between the inner blades is not sufficient, and it is difficult to uniformly disperse the mixture containing the filler. In addition, when mixed with a filler with a low specific gravity, the filler does not settle and stays near the upper layer of the mixture of water and a compound such as epoxy in the stirring layer, so the filler is not sufficiently taken up between the outer blade and the inner blade. It is difficult to uniformly disperse the mixture containing the filler. Further, the structure is complicated, and it is difficult to perform maintenance when a large amount of highly viscous substance such as resin such as epoxy is mixed. For this reason, the compound such as epoxy and the water and the filler constituting the mixture for forming the continuous porous material are not uniformly dispersed, and the formation of the emulsion and the uniform dispersion of the filler are not obtained. This causes variation in the quality, such as the strength, of the resin continuous porous body formed by the above method.

Furthermore, since the mixture for forming a continuous porous material is cured with time, it is required to form a uniform emulsion in a short time and to uniformly disperse the filler. When the stirring time becomes longer, the curing proceeds, and at the end of the stirring, the mixture for forming the continuous porous body becomes highly viscous and the mixture for forming the continuous porous body is poured and solidified to obtain a desired continuous porous body shape. In some cases, pouring is not possible.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for producing a continuous porous porous body made of a resin used for a slurry casting mold or the like, and a method of curing a compound such as epoxy with a compound such as epoxy. It is an object of the present invention to provide a stirring method for uniformly stirring a mixture for forming a continuous pored porous material containing an agent, a filler and water in a short time.

[0008]

In order to achieve the above object, the present invention provides a method for stirring a mixture for forming a continuous porous material, which comprises at least an epoxy compound, a curing agent, a filler, and water. It is characterized in that the mixture for forming a porous body is stirred using a reciprocating rotary stirrer having a reversing function instead of one-way rotation. By doing so, a turbulent flow is generated in the stirring vessel, and the resin and the filler can be uniformly dispersed and mixed.

In a preferred embodiment of the present invention, the reciprocating rotary stirrer includes two or more stirring blades or two or more stirring blades. By doing so, a turbulent flow is strongly generated in the whole of the stirring vessel, and it is possible to uniformly disperse and mix the resin within a time having a fluidity capable of pouring a resin in which various kinds of substances that cure in a hydrated state can be poured. Will be possible.

In a preferred embodiment of the present invention, the sectional shape of the stirring blade is changed depending on the specific gravity of the filler. By doing so, it is possible to change the direction of the vertical turbulence and to prevent sedimentation or to mix suspended matter according to the specific gravity of the filler.

[0011] In a preferred embodiment of the present invention, when the specific gravity of the filler is 1 or more, the cross-sectional shape of the stirring blade is such that the mixture causes a turbulent flow from above to below. By doing so, the turbulent flow toward the lower layer around the rotation axis collides with the bottom of the stirring tank and becomes a turbulent flow toward the upper layer of the stirring tank, and the filler to be settled is caused by the turbulent flow toward the upper layer. And the filler does not settle or stay in the lower layer of the stirring tank.
In addition, the turbulent flow makes it possible to disperse not only in a certain region in the stirring layer but also in any region.

In a preferred embodiment of the present invention, when the specific gravity of the filler is less than 1, the shape of the cross section of the stirring blade is such that the mixture causes a turbulent flow from below to above. By doing so, the turbulent flow toward the upper layer around the rotation axis becomes a turbulent flow toward the lower layer of the stirring tank along the inner wall of the stirring tank, and the filler to be floated flows into the lower layer of the stirring tank by the flow of the turbulent flow toward the lower layer. The filler is pushed down so that the filler does not float or stay in the upper layer of the stirring tank, and can be dispersed not only in a certain area but also in any area in the stirring layer by turbulence.

In a preferred embodiment of the present invention, a surfactant is added during the stirring. By doing so, turbulence is generated while significantly lowering the interfacial free energy or surface tension between the filler and the resin, thereby suppressing the dilatancy and thixotropic fluidity of the resin and allowing the filler to be uniformly dispersed and mixed. Become.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a continuous porous resin body is a resin layer having continuous pores obtained by mixing and solidifying a filler and water while containing a compound such as epoxy as a main component.

In the present invention, the mixture for forming a continuous porous material means a mixture in which a filler and water are mainly mixed with a compound such as epoxy.

In the present invention, the filler is a material capable of bonding to the epoxy compound, and includes silica powder, silica sand powder, glass powder, organic powder, microballoons and the like.

In the present invention, a surfactant is a substance composed of a hydrophobic group and a hydrophilic group, and is an anionic surfactant represented by a fatty acid salt, an alkyl sulfate ester salt, an alkyl sulfosuccinate salt or the like, or a polyoxyethylene alkyl. Nonionic surfactants represented by ethers, sorbitan fatty acid esters, polyoxyethylene fatty acid esters and the like.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Stirring using a reciprocating rotary stirrer having a reversing function generates a turbulent flow 4 in the stirring tank 1 as shown in FIG. 1 to obtain a fluid state covering the whole of the stirring layer 1 including the radial and axial directions. Therefore, the filler is easily dispersed throughout the stirring tank 1 in a short time. Further, the dispersion of the filler and the formation of the emulsion are promoted by the large shearing force received from the stirring blade 3 that repeats the reversing reciprocation, so that the filler can be more uniformly dispersed in the epoxy resin.

In a preferred embodiment of the present invention, a stirring blade having two blades 5 or two or more blades attached to a rotating shaft 2 as shown in FIG. 2 or a stirring blade having two or more stages attached to the rotating shaft 2 shown in FIG. The stirring blade equipped with the blade is used for a reciprocating rotary stirrer. As a result, the turbulent flow in the stirring tank is further subdivided and the shearing force of the stirring blade is increased, and the epoxy compound having one or more epoxy rings in one molecule reacts with the epoxy compound to cure the epoxy compound. It is possible to uniformly disperse and mix the filler in a complex mixed resin that cures in a water-containing state containing an agent, a filler, water and soluble salts, within a time period in which the mixed mixed resin has fluidity that can be poured. . The number of blades and the number of stages are set in accordance with the amount of the continuous porous resin and the shape, depth or diameter of the stirring layer.

In a preferred embodiment of the present invention, a surfactant is mixed with the mixture for forming a continuous porous material exhibiting dilatancy and thixotropic fluidity. When dilatancy and thixotropic fluidity are developed, a surfactant is added before or during stirring with a reciprocating rotary stirrer. This reduces the dilatancy and thixotropic fluidity of the resin due to the vertical turbulence generated by the reciprocating rotary stirrer and the strong shearing force of the stirring blades as well as the effect of lowering the surface free energy or the surface tension between the filler and the resin of the surfactant. , Non-dilatancy, non-thixotropic fluidity developing resin can be stirred in the same manner.

In a preferred embodiment of the present invention, as shown in FIGS. 1 and 4, the direction of the turbulent flow is arbitrarily changed by changing the cross-sectional shape of the stirring blade according to the specific gravity of the filler. When the specific gravity of the filler is 1 or more, preferably 1.5 or more, when using a stirring blade having a trapezoidal or triangular cross-sectional shape, the blade is attached so that the trapezoidal short side surface or the triangular vertex points downward. Thereby, by setting the turbulent flow 4 from the top to the bottom as shown in FIG. 1, the settling of the filler can be prevented, and uniform dispersion can be obtained.

The specific gravity of the filler is less than 1, preferably 0.5
In the following cases, when using a stirring blade having a trapezoidal or triangular cross section, the blade is attached so that the trapezoidal short side surface or the triangular vertex faces upward. As a result, FIG.
By making the turbulent flow 4 flow from the bottom to the top as shown in (1), it is possible to take in the floating filler and obtain a uniform dispersion.

[0023]

[Example 1] Materials prepared in the proportions shown in Table 1 were placed in a stainless steel container without a lid, and stirred for 10 minutes with a rotary agitator of a propeller type blade, a homogenizer, and a reciprocating rotary agitator. Two emulsion slurries were obtained. This emulsion slurry is 10 × 10
Cast into a water-impermeable mold surrounded by a vinyl chloride plate with a rectangular shape of × 120 mm and surrounding it on all sides, cover it so that water does not evaporate, and leave it in a room at 30 ° C for 42 hours to cure it while containing water and cure. I removed my body. Five specimens were prepared for each stirring method. [Table 1] The breaking strength of the obtained cured product was measured according to JIS K7203 (bending test method for hard plastic: three-point bending strength), and the bending strength was calculated from the breaking strength and the sample breaking size. Autograph AG-10KNE manufactured by Shimadzu Corporation was used as a material testing machine. Table 2 shows the test results. [Table 2] As shown in Table 2, it was found that the cured product produced by stirring with a reciprocating rotary stirrer had much higher bending strength and less variation in strength than the cured product produced by stirring with another stirrer.

[Example 2] Next, in the same preparation as in Example 1, continuous rotation of the propeller type blade and the homogenizer was performed to obtain a more uniform dispersion of the filler and a continuous time (visual sensation) until uniform emulsion formation. The viscosity of the mixture for forming a porous material was measured with a B-type viscometer. Table 3 shows the results. [Table 3] As shown in Table 3, long-time stirring is required for the propeller-type blade rotary stirrer and the homogenizer in order to obtain a uniform filler dispersion, and as a result, the viscosity of the mixture for forming a continuous porous material greatly increases. Then, it turned out that pouring was hindered.

[Example 3] Next, a formulation example (Table 4) in which dilatancy fluidity is developed and a result (Table 5) in which dilatancy fluidity is suppressed by adding a surfactant are shown. As the stirrer, a reciprocating rotary stirrer was used. [Table 4] [Table 5] In the case of a mixture exhibiting dilatancy flowability, it can be seen from the dispersion of the measured bending strength that it is difficult to uniformly disperse the filler and prepare a uniform emulsion using only a reciprocating rotary stirrer (without a surfactant). It was found that in a mixture exhibiting dilatancy fluidity, a uniform slurry can be prepared by adding a small amount of a surfactant at the time of preparation and stirring with a reciprocating rotary stirrer.

[0026]

According to the present invention, a mixture of a compound such as epoxy, a filler, and water is uniformly stirred and dispersed in a short time in the production of a resin continuous porous material used in a slurry casting mold. It is possible to provide a stirring method for obtaining a homogeneous mixture for forming continuous porous media.

[Brief description of the drawings]

FIG. 1 is a diagram showing a turbulent state in a stirring tank using a reciprocating rotary stirrer having a reversing function according to an embodiment of the present invention.

FIG. 2 is a diagram showing a two-blade stirring blade according to an embodiment of the present invention.

FIG. 3 is a view showing a single-stage two-stage stirring blade according to an embodiment of the present invention.

FIG. 4 is a diagram showing a turbulent state in a stirring tank in which a cross-sectional shape of a stirring blade according to an embodiment of the present invention is changed.

FIG. 5 is a view showing a conventional single blade stirring blade.

FIG. 6 is a view showing a mixing state in a stirring tank using a conventional general single-blade rotary stirrer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Stirring tank 2 ... Rotating shaft 3 ... Single blade 4 ... Turbulence 5 ... Two blades 6 ... Propeller type blade 7 ... Rotary flow

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Claims (6)

[Claims] 1. A method for agitating a mixture for forming a continuous porous body containing at least an epoxy compound, a curing agent, a filler, and water, wherein the mixture for forming a continuous porous body is reciprocated not having one rotation but a reversing function. A method for stirring a mixture for forming a continuous porous material, which comprises stirring using a rotary stirrer. 2. The method according to claim 1, wherein the reciprocating rotary stirrer has two or more or two or more stages of stirring blades. 3. The method for stirring a mixture for forming a continuous porous material according to claim 2, wherein the shape of the cross section of the stirring blade is changed depending on the specific gravity of the filler. 4. When the specific gravity of the filler is 1 or more,
The method for stirring a mixture for forming a continuous porous material according to claim 3, wherein the shape of the cross section of the stirring blade is such that the mixture causes a turbulent flow from above to below in the stirring tank. 5. When the specific gravity of the filler is less than 1,
4. The method for stirring a mixture for forming a continuous porous material according to claim 3, wherein the shape of the cross section of the stirring blade is such that the mixture causes a turbulent flow from below to above in the stirring tank. 6. The method for stirring a mixture for forming a continuous porous material according to claim 1, wherein a surfactant is added during the stirring.