KR20200141711A - Process for preparing bead typed super-absorbent polymer with UV on phase separation - Google Patents

Abstract

The present invention relates to a method for producing a bead type superabsorbent polymer which is an ultraviolet polymer using phase separation characteristics. In a constant flow of oil through a transparent tube or an open tube, a monomer aqueous solution containing a hydrophilic monomer, a crosslinking agent, and a photoinitiator is manufactured in a separate container by adjusting the viscosity of the aqueous solution in the range of 10 to 2000 cps with as a thickening agent. Then, a certain amount of the monomer aqueous solution is dropped into the oil flowing through the transparent tube or the open tube to make the water-soluble monomer roll in the oil due to the phase separation of oil and water, and subjected to a polymerization reaction through an ultraviolet irradiation device, thereby obtaining a spherical polymer. The dried resin obtained herein has an average particle size in the range of 0.1 to 10.0 mm, is a completely bead-like particle, has a narrow particle size distribution, maintains a transparent bead shape even when swelled by absorbing water, and has good absorption ability and gel strength for distilled water.

Description

Process for preparing bead typed super-absorbent polymer with UV on phase separation {Process for preparing bead typed super-absorbent polymer with UV on phase separation}

The present invention relates to a method for producing a bead-like superabsorbent polymer, and more particularly, to a method for producing a bead-like superabsorbent resin, which is a spherical polymer, through an ultraviolet irradiation device using the phase separation property of oil and water.

In order to use a super absorbent polymer for a special purpose such as a sustained-release formulation, it has a certain size and shape, and the desired sustained-release effect can be obtained only when the particles do not loosen even if left for a long time after absorbing water. , There is an urgent need to develop super absorbent polymer particles having a specific shape that is not amorphous.

In general, superabsorbent resins are made of synthetic materials made to have a three-dimensional network structure by polymerizing monomers having hydrophilic groups such as -OH, -NH2, -COOH, -SO3H with a crosslinking agent.

Partially neutralized acrylic acid is used as a hydrophilic monomer, and bulk polymerization, solution polymerization, reverse phase suspension polymerization, and reverse phase emulsion polymerization are mainly used as synthesis methods.Other methods are sprayed on a heated plate by spraying a polymerizable monomer. A method of polymerization is being used.

Block polymerization is a method of polymerizing a hydrophilic monomer with a crosslinking agent to perform three-dimensional crosslinking or to prepare a super absorbent polymer that is insoluble in water by means of self-crosslinking.It is difficult to control the heat of polymerization and obtain a polymer having a certain shape. it's difficult. Even in the case of solution polymerization, a crushing process is required after drying to make a particle state, and a process of selecting the particle size by size is required. Also, if the water is absorbed and left unattended, the particles will be loosened, resulting in a certain shape. It is not suitable for use as a sustained-release material that must maintain a certain shape for a long time because it cannot be maintained. Therefore, it is not possible to manufacture a super absorbent polymer having a certain shape by the bulk polymerization method or the solution polymerization method.

In order to prepare a super absorbent polymer having a certain particle shape, a reverse phase suspension polymerization method or a reverse phase emulsion polymerization method is generally applied. In particular, the reverse phase suspension polymerization method in which a water-soluble monomer is dispersed in a solvent and polymerized is a bead-shaped super absorbent polymer. It has been adopted as the most preferred method for manufacturing. The particle size of the super absorbent polymer formed by reverse phase suspension polymerization is in the range of approximately 10 to 500 μm. Factors that can control the size of the resin particles include the raw materials used, the HLB value of the surfactant, the type and amount of the dispersion stabilizer, the type and amount of the initiator, the type and amount of the crosslinking agent, the stirring speed, and the reaction temperature. It is known that the most influential factors are the stirring speed, the type and amount of the dispersant, and the reaction temperature.

In general, increasing the stirring speed decreases the particle size, and decreasing the stirring speed increases the particle size.In order to manufacture a relatively large bead-like superabsorbent resin with an average particle size in the range of 700 to 3000 µm, the stirring speed must be decreased. However, since the specific gravity difference between the solvent and the hydrophilic monomer is large, agglomeration occurs if not stirred above a certain stirring speed. Therefore, there is a limitation in preparing a bead-like superabsorbent polymer having a particle size in the range of 700 to 3000 µm by a general reverse phase suspension polymerization method.

The prior art related to the production of bead-like superabsorbent resin is as follows: U.S. Patent Nos. 4,459,396 and 4,497,930 disclose ethylcellulose, cellulose acetate, sorbitan fatty acid ester, sucrose fatty acid ester, glycerol fatty acid ester, nonylphenyl ether, etc. Was used as a protective colloid, and toluene, xylene, cyclohexane, and methylcyclohexane were used as a dispersion medium to prepare bead-shaped particles by reverse phase suspension polymerization.However, in the case of the bead-shaped superabsorbent polymer prepared in this way, the average particle size is 100 to It was in the range of 350 μm. In addition, Japanese Patent Laid-Open No. Hei 6-293802 uses silica powder as an inorganic salt in addition to sorbitan fatty acid ester, polyoxyethylene fatty acid ester, and saccharide fatty acid ester as a dispersion medium, and the stirring speed when polymerization proceeds and the conversion rate reaches 50% or more. A method of increasing the particle size without agglomeration was suggested as a method of increasing the dispersing power by increasing the value of the particle size.

In addition, U.S. Patent No. 4,937,632 uses a method of improving the particle size by increasing the viscosity of the monomer. As the thickener used, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, carboxymethyl cellulose, starch, polyacrylic acid, etc. were used. As a dispersion medium, sucrose fatty acid ester was used alone, and the bead phase was solidified by reverse phase suspension polymerization. A technology for producing a water absorbent resin has been disclosed, and a bead-like resin having a particle size in the range of 100 to 600 µm can be obtained at the time of manufacture by setting the viscosity of the monomer in the range of 15 to 5,000 cps, but when the viscosity of the monomer is in the range of 5,000 to 10,000 cps It has the disadvantage of obtaining sausage-shaped particles, not bead-like, and has poor water absorption and gel strength. As another known method, Korean Patent Laid-Open Publication No. 1999-57609 and US Patent No. 4,389,513 disclose a method of spraying a polymerizable registered patent No. 10-0492917 monomer onto a heating plate, or mixing a flowable polymer with a crosslinking agent to A method of manufacturing a super absorbent polymer in the form of particles by using a spraying method is known, but most of the particles are not bead-shaped, but are made of elliptical shape, have a small particle size, and have a disadvantage that a separate facility must be manufactured. . Although the above-described prior art attempted to prepare a super absorbent polymer having a large particle size, there was a limitation in increasing the particle size in the form of beads due to agglomeration between particles due to rapid polymerization heat during polymerization. In addition, if the heat of polymerization is controlled by an increase in the stirring speed, the particle size decreases, and the decrease in the stirring speed cannot control the heat of polymerization between the particles, resulting in agglomeration between particles.

As described above, as the application fields of super absorbent polymers are expanded to sustained release materials, the demand for super absorbent polymers having a specific shape is increasing. In particular, products that value appearance, such as fragrances, deodorants, and horticultural materials. In order to apply to sustained-release formulations, a product that maintains a certain shape even after absorption and has a larger particle size is required. In the case of a super absorbent polymer manufactured by a method known to date, it is difficult to apply it due to its small particle size. In addition, existing super absorbent resins have poor absorption capacity for aqueous solutions containing functional materials (fragrance, deodorant, insecticide, etc.), and their gel strength is poor, making it difficult to distinguish the shape due to particle pressing, so it is used in products that value appearance. There is a limit to the following.

KR 10-0492917 B1, May 24, 2005 KR 10-1999-0057609 A, 07/15/1999

The main object of the present invention is to provide a method for preparing a completely bead-like superabsorbent polymer having a constant size.

Another object of the present invention is to provide a method of preparing a bead-like superabsorbent polymer using an ultraviolet polymerization method that does not use a harmful organic solvent.

In addition, the present invention is prepared by an eco-friendly UV polymerization method that does not use a harmful organic solvent by using a phase separation phenomenon of a completely bead-like superabsorbent resin having excellent absorption capacity and gel strength and having a particle size in the range of 0.1 to 10.0 mm. Its purpose is to provide a method.

Other objects and advantages of the present invention will become more apparent by the following detailed description, claims and drawings.

The inventors of the present invention, in preparing a completely bead-like superabsorbent resin of a certain size, break away from the existing polymerization method using a harmful organic solvent, and determine the state of the polymer produced in real time using an ultraviolet polymerization method that does not use an organic solvent. As a manufacturing method that can be produced while checking, it uses a phase separation phenomenon with a fluid passing through a transparent tube or open tube having various inner diameters, and the input monomer rolls through the transparent tube and the open tube to form a sphere shape and is transparent. It is possible to adjust the size of the resin beads produced according to the inner diameter size of the pipe, the flow rate of the fluid, the viscosity and input rate of the monomer, and the inner diameter of the needle. By controlling the ratio of the monomer used and the amount of crosslinking agent, the gel strength and distilled water The present invention was completed by finding that the water absorption capacity can be increased, and when all the above-described conditions are satisfied, the desired complete bead-like superabsorbent polymer can be produced.

In order to solve the above technical problem, the present invention provides a method of preparing a completely bead-like superabsorbent polymer having a constant size while checking the state of a polymer produced in real time using an ultraviolet polymerization method without using an organic solvent.

The present invention uses a material that continuously passes through a transparent tube or open tube having various inner diameters at a constant speed and a monomer that is phase-separated to form spherical super absorbent polymer beads that are polymerized through a UV irradiation section through a transparent tube or an open tube. Provides a method of manufacturing.

Here, as a material that continuously passes through the transparent tube or the open tube at a constant speed, oil may be used.

In the present invention, the material of the transparent tube may be quartz, glass, PMMA (polymethyl methacrylate, polymethyl methacrylate), or the like.

In the present invention, the material of the open pipe is Teflon, PP (polypropylene, polypropylene), PE (polyethylene, polyethylene), PTFE (polytetrafluoroethylene, polytetrafluoroethylene), SUS (austenitic stainless steel), stainless steel, etc. Can be used.

In addition, in the present invention, the transparent pipe may have an inner diameter of 1 to 20 mm and a length of 30 to 300 cm.

In the present invention, the open pipe may be used having an inner diameter of 1 to 20 mm and a length of 30 to 300 cm, and preferably, an inner diameter of 8 mm and a length of 200 cm.

The present invention can prepare a bead-like superabsorbent polymer which is an ultraviolet polymer using the phase separation property.

In the present invention, it is possible to use an aqueous monomer solution that is phase-separated from oil continuously passing through a transparent tube or an open tube at a constant speed.

Here, the aqueous monomer solution may be prepared by mixing a hydrophilic monomer, a crosslinking agent, and a photoinitiator.

In the present invention, an aqueous monomer solution containing a hydrophilic monomer, a crosslinking agent, and a photoinitiator may be used as a thickener in a separate container, and the viscosity of the aqueous solution may be adjusted in the range of 10 to 2000 cps.

Here, the hydrophilic monomer is 1 selected from acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, acrylamide, methacrylamide, 2-acrylamide-2-methylpropanesulfonic acid, styrenesulfonic acid, and 2-hydroxymethacrylate. Hydrophilic monomers of more than one species can be used.

Here, the crosslinking agent may be a crosslinking agent having two or more functional groups so that the hydrophilic monomer can form a network structure, and the crosslinking agent is ethylene glycol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene Glycol dimethacrylate, glycidyl acrylate, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, N,N-methylenebisacrylamide, N-methylolacrylamide, triallylamine, triallyl One or more of cyanate, triallyl isocyanate, pentaerythritol, and the like can be selected and used.

Here, the photoinitiator may be used by selecting one or more from alpha-hydroxy-ketones & blend, phenyglyoxylate, alpha-Amino-ketone, Benzil dimethyl-ketal, Phosphine oxide, Metallocene, Iodonium salt, sulfonium salt, and the like.

Here, the thickener is used to maintain the size of the particles, xanthan gum, gum arabic, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxymethylpropylcellulose, carboxymethylcellulose, polyacrylic acid, polyacrylic One or more types of aqueous thickeners such as amide, carbapol (ultra-high molecular weight acrylic acid), and starch can be selected and used.

In one embodiment of the present invention, in a constant flow of oil through a quartz tube or Teflon open tube, in a separate container, a monomer aqueous solution containing a hydrophilic monomer, a crosslinking agent and a photoinitiator is used as a thickening agent and the viscosity of the aqueous solution is in the range of 10 to 2000 cps. The water-soluble monomer is rolled in the oil due to the phase separation of oil and water by dropping a certain amount into the oil flowing through the quartz tube or Teflon open tube and undergoing polymerization reaction through an ultraviolet irradiation device so that the average particle size is 0.1 to 10.0 ㎜ It is possible to prepare a superabsorbent polymer which is a spherical polymer in the form of a full bead in a range.

In the present invention, the ultraviolet irradiation device is a device capable of continuously emitting ultraviolet rays around 365 nm in a wavelength range of 265 to 420 nm and capable of up to 50 W to 200 W/cm.

However, the technical problem to be achieved by the present invention is not limited to the above-mentioned problems, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

The present invention can be prepared by an eco-friendly UV polymerization method that does not use a harmful organic solvent by using a phase separation phenomenon of a completely bead-like superabsorbent resin having excellent absorption capacity and gel strength and having a particle size in the range of 0.1 to 10.0 mm. .

1 is a schematic diagram of an ultraviolet polymerization apparatus.
2 is a block diagram of a tube in which spherical beads are formed by a phase separation phenomenon.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for describing the present invention in more detail, and it will be apparent to those of ordinary skill in the art that the scope of the present invention is not limited by these examples according to the gist of the present invention. .

Example 1

In a constant flow of oil through a quartz tube or Teflon open tube, in a separate container, a monomer aqueous solution containing a hydrophilic monomer, a crosslinking agent and a photoinitiator is used as a thickener to adjust the viscosity of the aqueous solution in the range of 10 to 2000 cps, and prepare a quartz tube or By dropping a certain amount into the oil flowing through the open Teflon tube, the water-soluble monomer rolled in the oil due to the phase separation of oil and water, and subjected to polymerization reaction through an ultraviolet irradiation device to obtain a spherical polymer.

The obtained dried resin has an average particle size in the range of 0.1 to 10.0 ㎜, is a completely bead-like particle, has a narrow particle size distribution, and maintains a transparent bead shape even when it is swelled by absorbing water, and has an absorption capacity and gel strength for distilled water. It was good.

Experimental Example 1

According to the following experimental conditions, the average particle size of the resin beads can be prepared in the range of 0.1 to 10.0 mm. The particle size distribution was also narrow, and even if it absorbs water and swells, it can maintain a transparent bead shape.

The open tube had an inner diameter of 8 mm and a length of 2 mm, and a silicone oil with a viscosity of 50 cps was used as the fluid, and the viscosity of the aqueous monomer solution was about 50 cps. It was manufactured to have an inner diameter of 3mm.

Experimental Example 2

The absorption capacity and gel strength of distilled water were good according to the following experimental conditions.

An ultraviolet polymerization bead-like superabsorbent resin was prepared using a water-soluble monomer having a molar ratio of acrylic acid and acrylamide of 1:3, a neutralization rate of 70%, a crosslinking agent of 0.016% and a solid content of 60 wt% relative to the monomer.

As described above, specific parts of the present invention have been described in detail, and it is clear that these specific techniques are merely preferred embodiments, and the scope of the present invention is not limited thereto for those of ordinary skill in the art. Accordingly, it will be said that the substantial scope of the present invention is defined by the appended claims and their equivalents.

Claims (3)

A method of producing spherical super absorbent polymer beads that are polymerized through an ultraviolet irradiation section using a fluid passing through a transparent tube or an open tube at a constant speed and a monomer that is phase separated.
The method of claim 1,
The material of the transparent tube is quartz, glass, PMMA,
The material of the open pipe is a method of manufacturing a super absorbent polymer bead, characterized in that Teflon, PP, PE, PTFE, SUS, stainless steel.
The method of claim 1,
The transparent tube or the open tube is a method for producing a super absorbent polymer bead, characterized in that the inner diameter of 1 ~ 20 mm, length 30 ~ 300 cm.

Images