JP7095326B2 - Polyvinyl chloride resin porous beads and their manufacturing method - Google Patents

Description

The present invention relates to polyvinyl chloride resin porous beads and a method for producing the same. More specifically, the present invention relates to a polyvinyl chloride resin porous bead having fine continuous pores from the outer layer to the center and having a hollow portion in the center and having a high porosity, and a method for producing the same.

Porous polymer materials have various functions and properties such as separation, adsorption, water absorption function, catalyst fixing / supporting function, heat insulation / buffer property, insulation property, sound absorption property, and light weight. Therefore, due to its separation functionality and adsorptivity, membrane / film-like separation membranes and medical materials, granular filter materials and adsorbents, packaging / packaging materials due to its light weight and cushioning properties, building materials and heat insulating materials due to its heat insulating properties, and sound absorption. It is useful in a wide range of applications, from sex to sound absorbing materials.

Further, as a polymer material, a vinyl chloride polymer is excellent in chemical resistance, acid resistance, alkali resistance, and weather resistance, and is useful as a general-purpose material because it is inexpensive.

Regarding the porous body of the vinyl chloride polymer, a chlorine-containing resin porous body having a specific void ratio and storage elasticity using water-soluble particles for forming the porous body (see, for example, Patent Document 1) and a vinyl chloride-based co-weight. The polymer is a continuous pore having a pore diameter of 0.1 to 40 μm, a skeleton diameter of 0.1 to 20 μm, and a thickness of 1 mm or more, which is obtained by cooling the polymerized solution to separate and drying the precipitated polymer. Polyvinyl chloride / acrylonitrile copolymer porous body (see, for example, Patent Document 2), PVC granules using an oil-in-water emulsion forming technique (see, for example, Patent Document 3), at a temperature of 100 to 180 ° C. A porous PVC small sphere having a narrow particle spectrum in the range of 1 to 5000 μm obtained by dissolving PVC in a solvent that forms a colloidal solution, cooling the solution, and separating the formed polymer small sphere. (See, for example, Patent Document 4) has been reported. Further, as a method for obtaining a polymer hollow body, a method for obtaining droplet particles containing a gas by injecting a gas into a resin liquid containing an oil-soluble surfactant (see, for example, Patent Document 5) has been reported. There is.

JP-A-2015-145485A International Patent Publication No. 2013-069681 Pamphlet Japanese Patent No. 5252414 Special Table 2000-516973 Gazette Japanese Unexamined Patent Publication No. 2016-131933

In adsorption or absorption applications, a small particle size results in a large pressure loss, and a low porosity or lack of continuous pores results in a decrease in adsorption or absorption efficiency. In general, a polymer porous body having pores of several nanometers to several hundreds of nanometers in which the amount of adsorption into the pores due to capillary condensation rapidly increases is a poor solvent phase separation method, a heat-induced phase separation method, or an empty body. It is difficult to make with a hole forming material.

A method of using water-soluble particles for forming a porous body disclosed in Patent Document 1, a method of cooling a high-temperature dissolved PVC solution disclosed in Patent Document 4, and an oil-soluble surfactant disclosed in Patent Document 5 are contained. In the method of injecting a gas into a resin solution to obtain droplet particles containing the gas, it is difficult to form a porous body having fine continuous pores. In the method of cooling the vinyl chloride-based copolymer solution disclosed in Patent Document 2 to separate the precipitated molded body, it is difficult to form a granular porous body having a high porosity, and the underwater oil type disclosed in Patent Document 3 is used. In the method for forming a porous body using the emulsion forming technique of No. 1, it was difficult to form a porous body having a large particle size.

An object of the present invention relates to polyvinyl chloride resin porous beads and a method for producing the same. More specifically, it is an object of the present invention to provide a polyvinyl chloride resin porous bead having fine continuous pores from the surface to the center of the bead and having a hollow portion inside the bead and having a high porosity, and a method for producing the same.

As a result of diligent studies to solve the above problems, the present inventors have found that the porous beads made of polyvinyl chloride resin have a pore ratio in the range of 50 to 95% and are hollow inside the beads. It has a portion, and a part of the pore diameter is in the range of 0.002 to 0.2 μm from the surface of the bead to the center, and the pore volume of the continuous pore is 0.03 cm ³ / g or more. Moreover, the polychloride is characterized in that the average space volume of the hollow portion located in the center of the beads among the plurality of hollow portions located inside the beads is 0.01 to 30% by volume with respect to the volume of the porous beads. We have found vinyl resin porous beads and a method for producing them, and have completed the present invention.

That is, the present invention
[1] Continuous holes having a pore ratio in the range of 50 to 95%, having a hollow portion inside the bead, and having a partial pore diameter in the range of 0.002 to 0.2 μm from the surface of the bead to the center. The pore volume of the continuous pores is 0.03 cm ³ / g or more, and the average space volume of the hollow portion located in the center of the bead among the plurality of hollow portions located inside the bead is porous. Polyvinyl chloride resin porous beads characterized by being 0.01 to 30% by volume with respect to the volume of the beads.

[2] A step of dissolving a polyvinyl chloride resin in a good solvent to obtain a polyvinyl chloride resin solution.
The step of forming droplets of the polyvinyl chloride resin solution obtained in the above step,
A step of immersing the droplets obtained in the above step in a poor solvent containing water to solidify the resin.
The polyvinyl chloride according to [1], which comprises a step of separating the solidified resin obtained in the above step from the solvent system, and the proportion of water in the poor solvent is 0.1 to 80% by weight. A method for manufacturing vinyl resin porous beads.

[3] The method for producing polyvinyl chloride resin porous beads according to [2], wherein the poor solvent is methanol or ethanol.

[4] The method for producing polyvinyl chloride resin porous beads according to [2], wherein the good solvent is dimethylacetamide.

[5] Production of the polyvinyl chloride resin porous beads according to [2], wherein the temperature of the step of immersing the droplets in a poor solvent containing water to solidify the resin is −15 to 50 ° C. Method.

Hereinafter, the present invention will be described in detail.

The porosity of the polyvinyl chloride resin porous beads in the present invention is in the range of 50 to 95%, preferably in the range of 70 to 95%, and more preferably in the range of 80 to 95%. preferable. When the porosity is higher than 50%, it is preferable in that the performance as a filter material or an adsorbent is excellent.

The porosity (P) of the polyvinyl chloride resin porous beads specified in the present invention is determined by the total pore volume (Vp) and the specific gravity of the polyvinyl chloride resin according to the following formula.

(In the formula, P represents the porosity (%) of the porous beads, Vp represents the total pore volume (cm ³ / g) of the porous beads, and ρ _PVC represents the specific gravity of the polyvinyl chloride resin.)
The total pore volume Vp of the polyvinyl chloride resin porous beads in the present invention is the total weight of the dried porous beads measured by measuring the weight of about 0.2 g and setting the weight at the time of drying (W ₀ ). Was added to 100 mL of methanol at 25 ° C. and allowed to stand for 48 hours. Next, the polyvinyl chloride resin porous beads sufficiently impregnated with methanol in the pores are taken out, spread on a dry filter paper, excess methanol on the surface is removed, the weight is measured, and the weight at the time of methanol impregnation (W). ₁ ). Using the weight of the porous beads when dried (W ₀ ), the weight when impregnated with methanol (W ₁ ), and the specific gravity of methanol (25 ° C), the total pore volume of the polyvinyl chloride resin porous beads according to the following formula (W 0). Vp) was calculated.

(In the formula, Vp represents the total pore volume (cm ³ / g) of the porous beads, W ₀ represents the weight (g) of the porous beads when dried, and W ₁ represents the methanol impregnation of the porous beads. Represents the weight (g) of, and ρ _MeOH represents the specific gravity of methanol)
The polyvinyl chloride resin porous beads in the present invention have a hollow portion inside the beads. A plurality of hollow portions are located inside the beads and are not particularly limited, but for example, they have a pore size of 10 to 1500 μm, and are preferably 10 to 500 μm in terms of excellent mechanical strength.

The polyvinyl chloride resin porous beads in the present invention have fine continuous pores from the bead surface to the hollow portion located at the center. The diameter of a part of the fine continuous holes is in the range of 0.002 to 0.2 μm.

The presence of continuous pores can be confirmed from the fracture surface of the polyvinyl chloride resin porous beads of the present invention, the SEM photograph of the surface, and the pore distribution measurement result by the gas adsorption method.

The polyvinyl chloride resin porous beads in the present invention have a pore volume of 0.03 cm ³ / g or more in the continuous pores. Further, having pores having a pore diameter of 0.002 to 0.2 μm in the outer layer, including mesopores having a pore size of 0.002 to 0.05 μm in which capillary condensation is likely to occur in an adsorption or absorption application, is efficient. It means that it is excellent in adsorption and absorption.

The pore volume of the continuous pores of the polyvinyl chloride resin porous beads in the present invention is determined by measuring the adsorption isotherm with a pore distribution measuring device (BELSORP-miniII manufactured by Microtrac Co., Ltd.) by a constant volume gas adsorption method, and BJH. It was obtained by analysis by the method.

The shape of the polyvinyl chloride resin porous beads in the present invention is substantially spherical, and the sphericity is not particularly limited. For example, the ratio of the longest diameter to the shortest diameter of the porous beads is 1. The range of 1 to 2 can be mentioned, and 1 to 1.5 is preferable in terms of excellent shape uniformity.

The size of the polyvinyl chloride resin porous beads in the present invention is not particularly limited, and for example, a bead diameter in the range of 0.1 to 10 mm can be mentioned, but it is excellent in productivity and handling. The bead diameter is preferably 0.5 to 5 mm.

Of the plurality of hollow portions located inside the polyvinyl chloride resin porous beads in the present invention, the average space volume of the hollow portion located at the center of the beads is 0.01 to 30% by volume with respect to the volume of the porous beads. Have. If the average space volume is less than 0.01% by volume, the porosity decreases, and if it exceeds 30% by volume, the strength decreases. The average space volume is preferably 0.01 to 30% by volume, more preferably 0.05 to 20% by volume, in terms of maintaining the porosity and excellent mechanical strength.

Of the plurality of hollow portions located inside the polyvinyl chloride resin porous beads in the present invention, the average spatial volume of the hollow portion located at the center of the beads is measured by measuring the longest diameter and the shortest diameter of the hollow portion using an SEM photograph. Then, the average value was taken as the hollow diameter, and the average space volume was calculated.

The raw material of the polyvinyl chloride resin porous beads in the present invention is not particularly limited, but for example, the average degree of polymerization of the polyvinyl chloride resin can be in the range of 400 to 4000, and its solubility in a solvent can be mentioned. It is preferably 400 to 2000 in terms of being excellent, but it is preferably 1000 to 4000 in terms of improving the thermal stability of the pores, and the average degree of polymerization may be selected according to the application. Further, two or more kinds of PVC having different average degrees of polymerization may be mixed and provided.

The polyvinyl chloride resin may contain a stabilizer, and the stabilizer is not particularly limited, but for example, an organic acid salt such as lead, barium, zinc, calcium, or tin, or an inorganic acid. Examples include salt. More specifically, the organic acid salt is not particularly limited, and examples thereof include barium stearate, zinc stearate, calcium stearate, lead stearate, dibutyltin dilaurate, and dibutyltin maleate. Be done. The inorganic acid salt is not particularly limited, and examples thereof include basic lead sulfate, basic lead carbonate, and basic lead phosphite. These stabilizers may be used alone or in combination of two or more.

The method for producing a polyvinyl chloride resin porous bead in the present invention is not particularly limited as a good solvent in the step of heat-dissolving the polyvinyl chloride resin in a good solvent to obtain a polyvinyl chloride resin solution. For example, dimethylacetamide, carbon tetrachloride, chlorobenzene, chloroform, cyclohexanone, o-dichlorobenzene, dimethylformamide, 1-methyl-2-pyrrolidone, 1,1,2,2-tetrachloroethane and the like can be mentioned. Among these good solvents, dimethylacetamide is preferable because it has excellent solubility of the polyvinyl chloride resin.

The temperature at which the polyvinyl chloride resin is heated and dissolved in a good solvent may be any temperature equal to or lower than the boiling point of the good solvent, and is not particularly limited, but may be in the range of 10 to 100 ° C. and is productive. From the viewpoint, 20 to 80 ° C. is preferable. Further, the dissolution method is not particularly limited, and examples thereof include stirring, pump circulation, shaking, and ultrasonic treatment.

In the step of heating and dissolving the polyvinyl chloride resin in a good solvent to obtain the polyvinyl chloride resin solution, the concentration of the polyvinyl chloride resin solution is not particularly limited, but is, for example, in the range of 1 to 50% by weight. Can be mentioned. If the concentration is less than 1% by weight, it is difficult to maintain the shape after droplet formation, and the bead strength is also lowered. Further, if the concentration is higher than 50% by weight, the viscosity of the polyvinyl chloride resin solution increases, which makes it difficult to form droplets. From the viewpoint of easy droplet formation and excellent productivity, the concentration of the polyvinyl chloride resin solution is preferably 3 to 50% by weight, more preferably 5 to 30% by weight.

In the step of forming droplets of the polyvinyl chloride resin solution obtained in the above step, the droplet forming method is not particularly limited, but for example, stirring, rotary spraying, spray spraying, vibrating dropping, and natural. Dropping is mentioned. As the droplet forming method, vibration-type dropping and natural dropping are preferable in that uniform porous beads can be obtained, and vibration-type dropping is more preferable from the viewpoint of productivity.

In the step of forming the droplets of the polyvinyl chloride resin solution, the temperature at which the droplets are formed may be in the range of 0 to 100 ° C. as long as the droplets can be formed, and is not particularly limited. From the viewpoint of productivity, 20 to 80 ° C. is preferable.

In the step of immersing the droplets obtained in the above step in a poor solvent containing water to solidify the resin, the poor solvent is not particularly limited, but for example, methanol, ethanol, propanol, iso-propanol, and the like. Examples thereof include butanol, and methanol is preferable from the viewpoint of versatility.

Further, the method for solidifying the droplets in a poor solvent is not particularly limited, and may be either standing or stirring. Stirring is preferable in that the droplets are solidified into a spherical shape.

Here, the ratio of the poor solvent water containing water is not particularly limited, but may be, for example, in the range of 0.1 to 80% by weight, and the porous beads can be easily formed and adsorbed. It is preferably 3 to 70% by weight in that it is excellent in forming holes having a hole diameter of 0.002 to 0.2 μm, which improves performance.

In the step of immersing the droplets in the poor solvent containing water to solidify the resin, the temperature at which the resin is solidified may be higher than the freezing point of the good solvent and lower than the glass transition temperature of the polyvinyl chloride resin. Although not particularly limited, the range of −15 to 50 ° C. can be mentioned, and −5 to 50 ° C. is preferable, and 0 to 40 ° C. is more preferable in terms of excellent productivity. The time for solidifying the resin is not particularly limited, but is preferably 0.25 hours or more in terms of excellent moldability.

In the step of separating the solidified resin obtained in the above step from the mixture of the good solvent, water and the poor solvent, as a pretreatment, solvent substitution for substituting the good solvent and the poor solvent contained in the solidified resin is performed. It is preferable to do so. For solvent substitution, the solidified resin is immersed in a new antisolvent. At this time, either stirring or standing may be performed, but stirring is preferable in terms of excellent replacement efficiency. The solvent replacement time is not particularly limited, but is preferably 0.5 hours or more in terms of excellent replacement efficiency. The temperature of the solvent substitution is not particularly limited as long as it is lower than the glass transition temperature of the polyvinyl chloride resin, but may be in the range of −15 to 70 ° C. From the viewpoint of excellent productivity, 0 to 50 ° C. is preferable, and 10 to 40 ° C. is more preferable.

In the step of separating the solidified resin from the mixture of the good solvent, water and the poor solvent, the separation method after the solvent replacement in the pretreatment is arbitrary, for example, vacuum filtration, pressure filtration, centrifugal filtration, decantation. , Centrifugal decantation, vacuum drying, heat drying, natural drying and the like can be used in combination. Further, the temperature at that time is not particularly limited as long as it is lower than the glass transition temperature of the polyvinyl chloride resin, but the range of −15 to 70 ° C. can be mentioned. 0 to 50 ° C. is preferable from the viewpoint of excellent productivity, and 10 to 40 ° C. is more preferable from the viewpoint of forming porous beads, which is a feature of the present invention.

According to the present invention, it is possible to provide porous beads of polyvinyl chloride resin having continuous pores and having a high porosity by an industrially advantageous method.

6 is an SEM photograph (magnification: 30 times) of a cross section of the polyvinyl chloride resin porous beads obtained in Example 1. 6 is an SEM photograph (magnification: 100,000 times) of the surface of the polyvinyl chloride resin porous beads obtained in Example 1. 6 is an SEM photograph (magnification: 25,000 times) of the vicinity of the outer shell portion of the cross section of the polyvinyl chloride resin porous beads obtained in Example 1. 6 is an SEM photograph (magnification: 30 times) of a cross section of the polyvinyl chloride resin porous beads obtained in Example 2. 6 is an SEM photograph (magnification: 50,000 times) of the surface of the polyvinyl chloride resin porous beads obtained in Example 2. 6 is an SEM photograph (magnification: 20,000 times) of the vicinity of the outer shell portion of the cross section of the polyvinyl chloride resin porous beads obtained in Example 2. 3 is an SEM photograph (magnification: 30 times) of a cross section of the polyvinyl chloride resin porous beads obtained in Example 3. 3 is an SEM photograph (magnification: 10,000 times) of the surface of the polyvinyl chloride resin porous beads obtained in Example 3. 3 is an SEM photograph (magnification: 10,000 times) of the vicinity of the outer shell portion of the cross section of the polyvinyl chloride resin porous beads obtained in Example 3. It is a graph which illustrates the pore distribution (0.002 to 0.2 μm) by the gas adsorption method of the obtained polyvinyl chloride resin porous beads. It is the result of the solvent absorption test of the polyvinyl chloride resin porous beads obtained in Example 1 and Example 3 and Comparative Example 1. It is the result of the thermal stability test of the polyvinyl chloride resin porous beads obtained in Example 3.

Hereinafter, the present invention will be described in more detail with reference to examples of the present invention, but the present invention is not to be construed as being limited by these examples. The obtained polyvinyl chloride resin porous beads were evaluated by the methods shown below.

[Observation by SEM]
Observation of polyvinyl chloride resin porous beads by SEM was performed by a JSM-6390LV scanning electron microscope (SEM) manufactured by JEOL.

To observe the cross section of the polyvinyl chloride resin porous beads, immerse the dried porous beads in ethanol, then freeze the ethanol-impregnated porous beads with liquid nitrogen, and then shave the frozen porous beads with a sword. The cut cross section was used as a sample.

[Average space volume of hollow part]
The average spatial volume of the hollow portion located in the center of the bead among the plurality of hollow portions located inside the polyvinyl chloride resin porous beads is measured by measuring the longest diameter and the shortest diameter of the hollow portion using SEM photographs. The average space volume was calculated with the average value as the hollow diameter.

[Bead diameter]
The longest diameter and the shortest diameter of the polyvinyl chloride resin porous beads were measured using SEM photographs, and the average value was taken as the bead diameter.

[Total pore volume]
The total pore volume of the polyvinyl chloride resin porous beads was measured by measuring the weight of about 0.2 g of the dried porous beads and taking the weight at the time of drying (W ₀ ), and the total weight of the measured beads was 50 mL of methanol at 25 ° C. Was added to and allowed to stand for 48 hours. Next, the polyvinyl chloride resin porous beads sufficiently impregnated with methanol in the pores are taken out, spread on a dry filter paper, excess methanol on the surface is removed, the weight is measured, and the weight at the time of methanol impregnation (W). ₁ ). Using the weight of the porous beads when dried (W ₀ ), the weight when impregnated with methanol (W ₁ ), and the specific gravity of methanol (25 ° C), the total pore volume of the polyvinyl chloride resin porous beads according to the following formula (W 0). Vp) was calculated.

(In the formula, Vp represents the total pore volume (cm ³ / g) of the porous beads, W ₀ represents the weight (g) of the porous beads when dried, and W ₁ represents the methanol impregnation of the porous beads. Represents the weight (g) of, and ρ _MeOH represents the specific gravity of methanol)
[Porosity]
The porosity (P) of the polyvinyl chloride resin porous beads was determined by the total pore volume (Vp) and the specific gravity of the polyvinyl chloride resin according to the following formula.

(In the formula, P represents the porosity (%) of the porous beads, Vp represents the total pore volume (cm ³ / g) of the porous beads, and ρ _PVC represents the specific gravity of the polyvinyl chloride resin.)
[Measurement of pore volume of 0.002 to 0.2 μm]
The pore volume of 0.002 to 0.2 μm was determined by measuring the adsorption isotherm with a pore distribution measuring device (BELSORP-miniII manufactured by Microtrac) by the constant volume gas adsorption method and analyzing by the BJH method. ..

Example 1
20 g of polyvinyl chloride resin (manufactured by Taiyo PVC, PVC homopolymer, grade TH-500, average degree of polymerization 450-550) is added to 80 g of dimethylacetamide, and the mixture is stirred at 70 ° C. to prepare 20% by weight of a polyvinyl chloride resin solution. did. 114 g of methanol and 6 g of water were mixed in a 200 mL glass container to prepare a water / methanol mixed solution (water ratio 5% by weight). 5 g of a polyvinyl chloride resin solution at 70 ° C. was added dropwise to the water / methanol mixed solution at 25 ° C. (water ratio: 5% by weight), and the droplets were allowed to stand for 30 minutes to solidify. The solidified droplets were taken out, placed in 100 g of fresh methanol, and allowed to stand at room temperature for 18 hours. Methanol was removed by filtration, and the filtrate was dried under reduced pressure at room temperature for 6 hours to obtain polyvinyl chloride resin porous beads A-1. The obtained polyvinyl chloride resin porous beads A-1 have a bead diameter of 2.5 mm, a porosity of 83%, a pore diameter range of 0.002 to 400 μm, and a pore volume (0.002 to 0.2 μm region). It had 14 cm ³ / g and an average space volume of 13% by volume in the hollow portion. The results are shown in Table 1. FIG. 1 is an SEM photograph (magnification: 30 times) of the cross section of the obtained polyvinyl chloride resin porous beads A-1, FIG. 2 is an SEM photograph of the surface (magnification: 100,000 times), and an SEM photograph near the outer shell portion. (Magnification: 25,000 times) is shown in FIG.

Example 2
In Example 1 above, instead of mixing 114 g of methanol and 6 g of water to prepare a water / methanol mixed solution (water ratio 5% by weight), 60 g of methanol and 60 g of water are mixed to prepare a water / methanol mixed solution. (Water ratio: 50% by weight) was prepared, and further, the poly was carried out by the same method as that described in Example 1 except that the temperature of the water / methanol mixed solution was set to 0 ° C instead of 25 ° C. Vinyl chloride resin porous beads A-2 were obtained. Table 1 shows the properties of the obtained polyvinyl chloride resin porous beads A-2. FIG. 4 is an SEM photograph (magnification: 30 times) of the cross section of the obtained polyvinyl chloride resin porous beads A-2, FIG. 5 is an SEM photograph of the surface (magnification: 50,000 times), and an SEM photograph near the outer shell portion. (Magnification: 20,000 times) is shown in FIG.

Example 3
10 g of polyvinyl chloride resin (manufactured by Taiyo PVC Co., Ltd., PVC homopolymer, grade TH-1700 (average degree of polymerization 1600-1800)) is added to 90 g of dimethylacetamide, and the mixture is stirred at 70 ° C. to prepare 10% by weight of a polyvinyl chloride resin solution. 72 g of ethanol and 48 g of water were mixed in a 200 mL glass container to prepare a water / ethanol mixed solution (water ratio 40% by weight). 5 g of a vinyl chloride resin solution at 70 ° C. was added to the water / water at 10 ° C. It was added dropwise to an ethanol mixed solution (40% by weight of water), and the droplets were stirred for 30 minutes to coagulate. The coagulated droplets were taken out, placed in 100 g of fresh ethanol, and allowed to stand at room temperature for 18 hours. It was removed by filtration, and the filtrate was dried under reduced pressure for 6 hours at room temperature to obtain polyvinyl chloride resin porous beads A-3. The properties of the obtained polyvinyl chloride resin porous beads A-3 are shown in Table 1. The SEM photograph (magnification: 30 times) of the cross section of the obtained polyvinyl chloride resin porous beads A-3 is shown in FIG. 7, and the SEM photograph of the surface (magnification: 50,000 times) is shown in FIG. 8, near the outer shell portion. The SEM photograph (magnification: 10,000 times) of the above is shown in FIG.

Example 4
Add 5 g of polyvinyl chloride resin (manufactured by Taiyo PVC, PVC homopolymer, grade TH-3800 (average polymerization degree 3500-4100)) to 95 g of dimethylacetamide and stir at 70 ° C. to prepare 5% by weight of polyvinyl chloride resin solution. A water / ethanol mixed solution (70% by weight of water) was prepared by mixing 36 g of ethanol and 84 g of water in a 200 mL glass container. 5 g of a vinyl chloride resin solution at 70 ° C. was added to the water / water at 10 ° C. It was added dropwise to an ethanol mixed solution (70% by weight of water), and the droplets were stirred for 60 minutes to coagulate. The coagulated droplets were taken out, placed in 100 g of fresh ethanol, and allowed to stand at room temperature for 18 hours. It was removed by filtration, and the filtrate was dried under reduced pressure for 6 hours at room temperature to obtain polyvinyl chloride resin porous beads A-4. The properties of the obtained polyvinyl chloride resin porous beads A-4 are shown in Table 1. Shown in.

Example 5
The methanol impregnation test of the polyvinyl chloride resin porous beads A-1 to A-4 obtained in Examples 1 to 4 was carried out. About 0.2 g of each of A-1 to A-4 was added to 50 mL of methanol, and the mixture was allowed to stand at 25 ° C. It was taken out at a predetermined time, and the weight of the methanol-impregnated porous beads was measured. The amount of methanol impregnated was determined from the difference between the dry weight of the porous beads used and the weight impregnated with methanol. Table 1 shows the results 30 seconds after the initial impregnation. The results of A-1 and A-3 are also shown in FIG.

Example 6
The polyvinyl chloride resin porous beads A-3 obtained in Example 3 were heat-treated at 80 ° C. for 100 hours in the atmosphere. Before and after the heat treatment, there was no change in the pore ratio, pore diameter, pore volume of 0.002 to 0.2 μm, average space volume of the hollow portion, and methanol impregnation amount by the methanol impregnation test. FIG. 12 shows the results of pore volumes of 0.002 to 0.2 μm.

Comparative Example 1
In Example 1 above, except that 114 g of methanol and 6 g of water were mixed to prepare a water / methanol mixed solution (water ratio 5% by weight), instead of water 120 g (water ratio 100% by weight). Polyvinyl chloride resin porous beads A-5 were obtained by the same method as that described in Example 1. Table 1 shows the properties of the obtained polyvinyl chloride resin porous beads A-5.

Comparative Example 2
In Example 1, 20 g of a polyvinyl chloride resin (manufactured by Taiyo PVC Co., Ltd., PVC homopolymer, grade TH-500, average degree of polymerization 450-550) was added to 80 g of dimethylacetamide, and the mixture was stirred at 70 ° C. to obtain a polyvinyl chloride resin. Instead of preparing 20% by weight of the solution, 10 g of a polyvinyl chloride resin (manufactured by Taiyo PVC, PVC homopolymer, grade TH-500, average degree of polymerization 450-550) was added to an acetone / water / THF mixed solution (1 / 0. 3 / 0.9 volume ratio) In addition to 100 g, the mixture was stirred at 45 ° C. to prepare 10% by weight of a polyvinyl chloride resin solution, but the solution was cloudy and a uniform polyvinyl chloride resin solution could be obtained. There wasn't.

Comparative Example 3
A methanol adsorption test of the polyvinyl chloride resin porous beads A-5 obtained in Comparative Example 1 was carried out. About 0.2 g of the polyvinyl chloride resin porous beads A-5 obtained in Comparative Example 1 was added to 50 mL of methanol, and the mixture was allowed to stand at 25 ° C. It was taken out at a predetermined time, and the weight of the methanol-impregnated porous beads was measured. The amount of methanol adsorbed was determined from the difference between the dry weight of the porous beads used and the weight impregnated with methanol. The results 30 seconds after the initial impregnation are shown in Table 1 and FIG.

Reference example 1
In Example 1 above, instead of mixing 114 g of methanol and 6 g of water to prepare a water / methanol mixed solution (water ratio 5% by weight), 120 g of methanol (water ratio less than 0.01% by weight) is used. board. 5 g of a polyvinyl chloride resin solution at 70 ° C. was added dropwise to methanol at 25 ° C., and the droplets were allowed to stand for 30 minutes to solidify, but the droplet shape could not be maintained and became irregular, and the polyvinyl chloride resin porous beads became irregular. Could not be obtained.

The polyvinyl chloride resin porous beads of the present invention are excellent in chemical resistance, acid resistance, alkali resistance, and weather resistance, have fine continuous pores from the outer layer to the center, have hollow portions inside the beads, and have pores. Due to its high rate, it is expected to be applied to a wide range of fields such as adsorption / absorption and separation of various substances, removal of harmful substances, recovery of valuable substances, and carriers of catalysts.

Claims (5)

It has a pore ratio in the range of 50 to 95%, a hollow portion inside the bead, and a continuous hole having a partial pore diameter in the range of 0.002 to 0.2 μm from the surface of the bead to the center. The pore volume of the continuous pores is 0.03 cm ³ / g or more, and the average space volume of the hollow portion located in the center of the beads among the plurality of hollow portions located inside the beads is the volume of the porous beads. Polyvinyl chloride resin porous beads characterized by being 0.01 to 30% by volume. A process of dissolving a polyvinyl chloride resin in a good solvent to obtain a polyvinyl chloride resin solution,
The step of forming droplets of the polyvinyl chloride resin solution obtained in the above step,
A step of immersing the droplets obtained in the above step in a poor solvent containing water to solidify the resin.
The polyvinyl chloride according to claim 1, further comprising a step of separating the solidified resin obtained in the above step from the solvent system, wherein the proportion of water in the poor solvent is 0.1 to 80% by weight. A method for manufacturing vinyl resin porous beads. The method for producing polyvinyl chloride resin porous beads according to claim 2, wherein the poor solvent is methanol or ethanol. The method for producing polyvinyl chloride resin porous beads according to claim 2, wherein the good solvent is dimethylacetamide. The method for producing a polyvinyl chloride resin porous bead according to claim 2, wherein the temperature of the step of immersing the droplets in a poor solvent containing water to solidify the resin is −15 to 50 ° C.

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