KR20170059937A - A crosslinked polyitaconic acid for super absorbent polymer - Google Patents

Abstract

The present invention relates to polyitaconic acid crosslinked by a crosslinking agent, and specifically, to a crosslinked polyitaconic acid polymer having a three-dimensional network having a hydrophilic ion group inside the polymer, a production method thereof, and a use thereof. Polyitaconic acid is crosslinked by a crosslinking agent according to the present invention, and a super absorbent crosslinked polyitaconic acid polymer with a three-dimensional network having a hydrophilic ion group inside the polymer has a high content of hydrophilic functional groups, and can produce a super absorbent resin.

Description

[0001] The present invention relates to a superabsorbent polyetaconic acid crosslinked polymer,

The present invention relates to a superabsorbent polybutanedicarboxylic acid crosslinked polymer and a process for its preparation and use.

Super Absorbent Polymer (SAP) is a synthetic polymer material capable of absorbing moisture from about 500 to 1,000 times its own weight. Super Absorbent Material (SAM) or Absorbent Gel Material). Such a superabsorbent resin has been put into practical use as a sanitary article, and nowadays, in addition to sanitary articles such as diapers for children, there are currently used soil repair agents for gardening, index materials for civil engineering and construction, sheets for seedling growing, freshness- And has been widely used as a material for various purposes.

The above-mentioned superabsorbent resin can be generally produced by polymerizing a resin monomer, drying and pulverizing the resultant to obtain a powdery product. Further, as a method for producing such a superabsorbent resin, there are known methods such as reversed-phase suspension polymerization or aqueous solution polymerization. Methods of aqueous solution polymerization include a thermal polymerization method in which the hydrogel polymer is polymerized while being broken and cooled in a kneader having several shafts and a method in which a high concentration aqueous solution is irradiated with ultraviolet rays or the like on a belt to perform polymerization and drying simultaneously And the like are known.

BACKGROUND ART Conventionally, polyitaconic acid is known to be prepared by using a radical initiator or by adding an alkaline solution to hydrolysis (DAWID STAWSKI et al., Polymery 2005, 50, 118-122 and Jovan Velickovic et al , Polymer Bulletin, 1994, 32, 169-172).

On the other hand, in order to obtain a polymer having more excellent physical properties, surface modification is applied to the resin powder obtained in the course of polymerization, pulverization, drying or final pulverization, or various process modifications are made to increase the efficiency of the polymerization, have.

It is an object of the present invention to provide a superabsorbent polyantaconic acid crosslinked polymer and a process for producing the same and a use thereof.

The first aspect of the present invention provides a polytetaconic acid crosslinked polymer wherein a polyetaconic acid is crosslinked with a crosslinking agent and a three-dimensional network having a hydrophilic ion group inside the polymer is formed.

A second aspect of the present invention is a method for preparing an itaconic acid-containing solution containing itaconic acid, an anhydride or salt thereof, a surfactant and an organic solvent (step 1); And a step of adding a cross-linking agent and a polymerization initiator to the itaconic acid-containing solution to produce a polytetaconic acid cross-linked polymer (step 2).

In a third aspect of the present invention, there is provided a process for neutralizing (Step 1) neutralizing itaconic acid, its anhydride or salt by adding a basic substance at 20 to 90 ° C; And a step of adding a crosslinking agent and a polymerization initiator to the resultant of the preliminary step to produce a polytetaconic acid crosslinked polymer (step 2).

A fourth aspect of the present invention provides an absorbent composition comprising a polytetaconic acid crosslinked polymer produced by the method of the second or third aspect of the present invention.

A fifth aspect of the present invention provides an absorbent (water-absorbing) product having a sheet layer containing a polytetaconic acid crosslinked polymer according to the first aspect of the present invention.

Hereinafter, the present invention will be described in detail.

The present invention provides a polyetaconic acid crosslinked polymer in which a three-dimensional network having a hydrophilic ion group inside a polymer is formed using a crosslinking agent in order to add a high degree of superabsorbent property to polyetaconic acid capable of exhibiting water absorption due to a large number of hydrophilic functional groups Feature.

The polytetaconic acid crosslinked polymers according to the present invention exert a high osmotic pressure due to the ionic groups in the polymer to allow water to enter the polymer. In this case, the absorbed water can be trapped in the crosslinked net of the polymer (net) and can be kept in a swollen state, so that it can have higher absorbency.

In addition, the polytetaconic acid crosslinked polymer according to the present invention can be partially or wholly neutralized with a hydrophilic ion group (e.g., -COO < ^- >), whereby a superabsorbent resin having an osmotic pressure ) Is improved.

Itaconic acid is an organic compound that can be derived from non-toxic and renewable resources. Homopolymer of itaconic acid is biodegradable. Itaconic acid can be obtained by distillation of citric acid or fermentation of saccharides such as glucose using Aspergillus terreus. Itaconic acid may be referred to as methylene succinic acid or 2-methylidenebutane diacid. Itaconic acid can be represented by the formula C ₅ H ₆ O ₄ or by the formula CH ₂ = C (COOH) CH ₂ COOH.

Generally polytitanic acid can be prepared from itaconic acid, or an anhydride or salt thereof. The salt may include sodium, potassium or ammonium salts of itaconic acid. The salts may include alkylated ammonium salts such as triethylammonium salts, and hydroxylalkylated ammonium salts such as triethanolammonium salts and the like.

Itaconic acid, itaconic anhydride, or itaconic acid salt may be used in an amount of 10 to 100% by weight, preferably 50 to 100% by weight, based on the total weight of the polybutanedicarboxylic acid polymer

Polyitaconic acid may be an itaconic homopolymer prepared from the form of itaconic acid, itaconic anhydride, itaconic acid salt, and mixtures thereof. In the case of polytetalic acid homopolymers, the polytetaconic acid backbone comprises structural units derived from itaconic acid, or an anhydride or salt thereof.

In the case of itaconic acid, it is easy to cause a termination reaction because of allyl-site hydrogen. Therefore, it is necessary to design a polymerization method and a reaction condition to overcome it, so that a polyetaconic acid crosslinked polymer having a three-dimensional network having a hydrophilic ion group inside the polymer can be produced .

In one embodiment of the present invention, a material having high functionality was used for increasing the crosslinking density, and a crosslinking agent having good bonding strength with itaconic acid was selected through experiments. The lower the molecular weight of the crosslinking agent, the higher the crosslinking density.

Non-limiting examples of cross-linking agents that can be used in the present invention include a material having two or more ethylenically unsaturated groups, a polyol that is a material having two or more hydroxy groups, a material having two or more epoxy groups, A material having two or more amine groups, a material having two or more urea groups, or a mixture thereof.

Non-limiting examples of the crosslinking agent include ethylene glycol, glycerol, 1,3-propanediol, starch, pentaerythritol, trimethylolpropane, sorbitol, sucrose, xylitol glucose, resorcinol, catechol, pyrogallol, glycated urea , 1,4-cyclohexanediol, diethanolamine, triethanolamine, polyethylene glycol diacrylate, tetraethylene glycol diacrylate, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl Propylene glycol diglycidyl ether, N, N-bisacrylamide ethylene glycol diglycidyl ether, ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, tetraethylene Glycol, propanediol, dipropylene glycol, polypropylene glycol, glycerin, poly Glycerol, butane diol, can be heptane diol, hexane diol, trimethylolpropane, penta-erythro recall, sorbitol, or mixtures thereof.

The content of the crosslinking agent in the polybutanedicarboxylic acid crosslinked polymer is preferably from 0.1 to 2% by weight based on the total weight of the poly (itaconic acid) crosslinked polymer. The basic properties of superabsorbent resin (SAP) have been well demonstrated in the above range of use through experiments.

The polytetaconic acid crosslinked polymer according to the present invention may be in the form of a powder prepared by drying, crushing or both.

The polytetaconic acid crosslinked polymer according to the present invention may have a coverage capacity in the range of 15 to 20 g / g in 0.9% NaCl solution. The polytetaconic acid crosslinked polymer according to the present invention can have a pressure absorption capacity in the range of 5 to 15 g / g at 0.3 psi in 0.9% NaCl solution. The polytetaconic acid crosslinked polymer according to the present invention may contain water in an amount ranging from 10 to 20% by weight in a 0.9% NaCl solution.

According to the present invention, there is a problem that when the polytetaconic acid crosslinked polymer having a three-dimensional network structure having a hydrophilic ion group inside the polymer is produced, the gel is hardly changed. Due to the hard gel, the crushing and drying process takes a lot of time and energy. As a method to solve this problem, it is possible to efficiently shorten the crushing and drying process through the production of particulate polytetaconic acid through the reversed phase suspension polymerization of itaconic acid. Also, in the case of itaconic acid, polymerization is preferably carried out at a low temperature, for example, by a polymerization method which overcomes this problem because a terminal reaction is apt to occur due to an allyl-site hydrogen.

Therefore, only when the polymerization reaction is designed in consideration of these points, a polyetaconic acid crosslinked polymer having a three-dimensional network having hydrophilic ion groups inside the polymer can be produced.

In one embodiment, a method for preparing a polyetaconic acid crosslinked polymer having a three-dimensional network structure having hydrophilic ion groups inside a polymer according to the present invention comprises:

Preparing an itaconic acid-containing solution containing itaconic acid, an anhydride or salt thereof, a surfactant, and an organic solvent (step 1); And

(Step 2) of adding a crosslinking agent and a polymerization initiator to the itaconic acid-containing solution to form a polytetaconic acid crosslinked polymer,

(See Example 1).

The process for producing the polyketanic acid crosslinked polymer is a reversed-phase suspension polymerization method, which is produced in the form of particles and is easy to process. By using a surfactant, dispersion of monomers on a solvent is facilitated, and a particulate phase can be obtained by reaction in the micelle of the monomer.

 Therefore, since the polytetaconic acid crosslinked polymer can be obtained in the form of particles, there is no need for a separate crushing process, and an organic solvent is used, which makes it easy to dry.

Nonlimiting examples of the organic solvent include water-insoluble solvents such as toluene, xylene, benzene, n-hexane, isohexane, n-pentane, isopentane, n-heptane, isoheptane, n-octane, nonane, decane, isooctane, , Cyclopentane, and the like.

The organic solvent may further comprise water. At this time, the amount of water can be adjusted so that the water-soluble substance is dissolved well.

Non-limiting examples of such surfactants include sorbitan monolaurate, sorbitan monostearate, sorbitan monooleate, polyoxyethylene (20) sorbitan monolaurate (20) Sorbitan Monolaurate, Polyoxyethylene (20) Sorbitan Monostearate, Polyoxyethylene (20) Sorbitan Monooleate, Polyoxyethylene (20) Sorbitan Monooleate or Polyoxyethylene There is a mixture.

The itaconic acid-containing solution may further contain an acid. In order to lower the solubility in a nonpolar organic solvent. Non-limiting examples of acids include nitric acid, hydrochloric acid, sulfuric acid, hydroquinone, and hydrofluoric acid.

Non-limiting examples of the polymerization initiator Na ₂ S ₂ O _5, and sodium sulfate _{(Sodium persulfate; Na 2 S 2} O 8), potassium persulfate _{(Potassium persulfate; K 2 S 2} O 8), 2, 2- azobis - (2-amidinopropane) dihydrochloride, 2,2-azobis- (N, N-dimethylene) isobutyramide dihydrochloride (2,2- 2-azobis [2- (2-imidazolin-2-yl) isobutyramide dihydrochloride, 2- (carbamoylazo) isobutylonitrile, Azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride), 2,2'-azobisisobutyronitrile, 4,4-azobis - (4-azobis- (4-cyanovaleric acid)).

The polytetaconic acid crosslinked polymer prepared by the above production method can be selectively neutralized with an alkaline solution selected from the group consisting of sodium hydroxide, ammonia, calcium hydroxide and sodium hydrogen carbonate. This is because the ionic group is introduced into the polymer to enhance the ability of SAP to generate osmotic pressure.

In another embodiment, a method for producing a polyetaconic acid crosslinked polymer in which a three-dimensional network having a hydrophilic ion group inside a polymer is formed,

Neutralizing (step 1) neutralizing itaconic acid, its anhydride or salt by adding a basic substance at 20 to 90 ° C; And

Adding a crosslinking agent and a polymerization initiator to the result of the previous step to produce a polytetaconic acid crosslinked polymer (step 2)

(See Example 2).

The polytetaconic acid crosslinked polymer is prepared by using an aqueous solution polymerization method, and water is used as a solvent, so that the polytetaconic acid crosslinked polymer produced is dried and crushed but is environmentally friendly without using an organic solvent.

It is preferable to control the reaction conditions at a low temperature such as 20 to 90 ° C in order to overcome the end reaction due to the allyl hydrogen of itaconic acid.

In the step 1, a solvent may not be used or water may be used.

By neutralizing itaconic acid in step 1, it is possible to enhance the ability of the polytetaconic acid crosslinked polymer capable of generating osmotic pressure by introducing an ionic group into the interior of the polymer. In addition, the solubility of itaconic acid in water can be increased.

Non-limiting examples of the basic material may be sodium hydroxide, ammonia, calcium hydroxide, sodium hydrogencarbonate, or a mixture thereof.

The resulting polytetaconic acid crosslinked polymer can be obtained by precipitation in a water-soluble organic solvent. Non-limiting examples of the water-soluble organic solvent include water, methanol, ethanol, propanol, butanol, acetone, N, N-dimethylformaldehyde, dimethylsulfoxide or a mixture thereof.

On the other hand, the present invention can provide an absorbent (water-absorbing) product having a sheet layer containing a polytetaconic acid crosslinked polymer according to the present invention. Non-limiting examples of the absorbent article include sanitary articles, diapers, sanitary articles, garden soil repair agents, civil engineering or architectural index materials, seedling-use sheets, food freshness preservatives or fomentation supplies.

As a non-limiting example, the polytetaconic acid crosslinked polymer-containing sheet can be produced in the form of an absorbent sheet by appropriately mixing pulp and superabsorbent resin.

According to the present invention, the crosslinked polyetaconic acid is crosslinked with a crosslinking agent, so that the crosslinked polymer of superabsorbent polyetaconic acid having a three-dimensional network structure having a hydrophilic ion group inside the polymer is not only rich in hydrophilic functional groups but also capable of producing a superabsorbent resin.

1 is a schematic view of a pressure absorption capability measuring apparatus.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, the following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited to the following examples.

Experimental Example 1

The superabsorbent resin (SAP) prepared in the following examples was pulverized through a pulverizer, and then its water retention capacity, pressure absorption capacity and water content were measured by the following methods.

<Measurement of Support Function>

① 200 ml of distilled water was added to the beaker, and NaCl was added to 0.9 wt.% NaCl solution for dissolution.

② 0.2 g of granular SAP was precisely weighed using a clean, dry herbage paper. A wire mesh teabag made of 100 mesh was made and put into a beaker containing NaCl aqueous solution.

③ SAP carefully put into the tea bag.

④ After checking the temperature and time, tea bag was taken out from the solution after 30 minutes, and dehydrated by centrifugal force of 300 G (gravity) for 3 minutes using a centrifuge.

⑤ After the centrifugation, the tea bag was carefully opened to remove the swollen SAP and the mass was measured.

       (Se) = (W1 - W0) / W0

                W1 = weight of swollen SAP

                W0 = Weight of the first SAP loaded

<Measurement of pressure absorption capacity>

The pressure absorption ability measuring apparatus of Fig. 1 was manufactured as follows.

① Place a ceramic filter plate (d = 80mm, h = 5mm) on a Petri dish and cut filter paper into ceramic filter plate.

② Place dried SAP (0.9 ± 0.01g) on metal mesh on filter paper.

③ Plexiglass cylinder (d = 60mm, h = 50mm) was placed in the center of the filter paper and the piston (Teflon d = 60mm) was placed on the dried SAP.

④ 0.9% salt water was added to the filter paper while the load (0.3 psi) of the piston weight was applied to the SAP.

⑤ In order to prevent concentration changes through evaporation of other environmental factors and salt water, the whole equipment was sealed with an acrylic box.

After 60 minutes, the weight of the swollen particles was measured.

       AUL (g / g) = (W2 - W1) / W1

              W1 = weight of dried SAP

<Component measurement for water>

① 200 ml of 0.9 wt% NaCl aqueous solution was put into a 250 ml beaker using a cylinder.

② 1 g of particulate SAP was precisely weighed and placed in a beaker.

(3) The mixture was swelled in a magnetic stirrer at 500 rpm for 16 hours with stirring.

④ Wait until the swollen gel is completely settled on the bottom.

⑤ The swelled gel and supernatant were separated through a filter.

⑥ The weight of the supernatant was measured, and the weight (WNaCl) of NaCl contained in the supernatant was theoretically calculated. (Example) If the supernatant is 100 g, WNaCl is 0.9 g.

⑦ The weight (W) of the residue was measured after the water was completely removed from the supernatant by distillation under reduced pressure.

* Calculation method

Water component W (%) = (W (g) - WNaCl (g)) / 1 gx100

Example 1

30 g of itaconic acid, 150 ml of toluene, 10 ml of distilled water, 1.5 ml of sorbitan monooleate (span-80) as a surfactant and a slight amount of HCl were added to a 250 ml three-necked flask equipped with a thermometer, After purging with nitrogen for 10 minutes, the mixture was heated to 80 DEG C and mixed. After adding 3 g of polyethylene glycol diacrylate (Mw: 500 g / mol) as a crosslinking agent to the reactor, 0.45 g of 2,2'-azobisisobutyronitrile as an initiator was dissolved in a small amount of acetone and introduced into the reactor through a syringe And the mixture was stirred for 2 hours and 30 minutes. The resulting polymer, crosslinked polytetaconic acid, was filtered and washed with acetone. Thereafter, 100 ml of a 2M NaOH aqueous solution was added to the polymer, followed by stirring for 1 hour. The swollen polymer was filtered, washed thoroughly with distilled water and alcohol, and then vacuum dried (yield: 81%) for 7 hours.

As a result of measuring the physical properties, the water retention capacity was 18 g / g and the compressive capacity was 11 g / g at 0.3 psi and the water content was 15 wt.% In 0.9% NaCl solution.

Example 2

52 g (0.4 mol) of itaconic acid was added to a 250 ml four-necked flask equipped with a thermometer, a water-cooled condenser, a material input line and a mechanical stirrer. Subsequently, 16 g (0.4 mol) of NaOH was slowly added thereto to partially neutralize, To dissolve the monomer. Thereafter, 0.52 g of polyethylene glycol diacrylate (Mw: 500 g / mol), which is a crosslinking agent, was added to the reactor. 1.5 g of Na ₂ S ₂ O ₅ was dissolved in 20 ml of distilled water, slowly added to the reactor and stirred at 30 ° C. The reaction was allowed to proceed for 5 hours, and the resulting polymer, crosslinked polytetaconic acid, was precipitated in acetone, filtered and dried in a 50 DEG C vacuum oven for 7 hours (yield: 90%).

As a result of measuring the physical properties, the water absorption capacity and the water content of the 0.9% NaCl solution were 16 g / g and 0.3 psi, respectively.

Claims (14)

In the presence of a crosslinking agent at a temperature of 20 to 90 占 폚 so as to have an adsorption capacity in the range of 15 to 20 g / g in 0.9% NaCl solution or a pressure absorption capacity in the range of 0.3 psi to 5 to 15 g / g in 0.9% Itaconic acid, or an anhydride thereof or a salt thereof to cause crosslinking of the polylactic acid with the crosslinking agent,
A polyetaconic acid crosslinked polymer having a three-dimensional network structure having a hydrophilic ion group inside the polymer,
The crosslinking agent may be a substance having two or more ethylenically unsaturated groups, a polyol that is a substance having two or more hydroxy groups, a substance having two or more epoxy groups, or a substance capable of causing a dehydration reaction in two carboxyl groups, A substance having two or more urea groups, or a mixture thereof,
Wherein the content of the crosslinking agent is 0.1 to 2% by weight based on the total weight of the polytetaconic acid crosslinked polymer.
The polytetaconic acid crosslinked polymer according to claim 1, characterized in that some or all of the hydrophilic ionic groups are neutralized to improve the holding ability of the polytetaconic acid crosslinked polymer.
The composition according to claim 1, wherein the crosslinking agent is selected from the group consisting of ethylene glycol, glycerol, 1,3-propanediol, starch, pentaerythritol, trimethylolpropane, sorbitol, sucrose, xylitol glucose, resorcinol, catechol, pyrogallol, Urea, 1,4-cyclohexanediol, diethanolamine, triethanolamine, polyethylene glycol diacrylate, tetraethylene glycol diacrylate, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl Diethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, N, N-bisacrylamide ethylene glycol diglycidyl ether, diethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol, Dipropylene glycol, polypropylene glycol, polyglycerin, butanediol, heptanediol, hexanediol Propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol, propylene glycol,
Preparing an itaconic acid-containing solution containing itaconic acid, an anhydride or salt thereof, a surfactant, and an organic solvent (step 1); And
Adding a crosslinking agent and a polymerization initiator to the itaconic acid-containing solution to form a polytetaconic acid crosslinked polymer at a temperature of 20 to 90 DEG C (step 2)
A process for producing a polytetaconic acid crosslinked polymer according to any one of claims 1 to 3.
The composition of claim 4, wherein the surfactant is selected from the group consisting of sorbitan monolaurate, sorbitan monostearate, sorbitan monooleate, polyoxyethylene (20) sorbitan monolaurate Polyoxyethylene (20) Sorbitan monolaurate, polyoxyethylene (20) sorbitan monostearate, and polyoxyethylene (20) sorbitan monooleate. &Lt; / RTI &gt; selected from the group consisting of polylactic acid and polylactic acid.
5. The method of claim 4, further comprising neutralizing the polytetaconic acid crosslinked polymer with an alkaline solution.
5. The process according to claim 4, wherein the itaconic acid-containing solution contains an acid selected from the group consisting of nitric acid, hydrochloric acid, sulfuric acid, hydroquinone and hydrofluoric acid solution.
Neutralizing (Step 1) adding basic substance to itaconic acid, an anhydride thereof or a salt thereof at 20 to 90 ° C to neutralize it; And
Adding a cross-linking agent and a polymerization initiator to the result of the pre-stage to produce a polytetaconic acid cross-linked polymer at a temperature of 20 to 90 DEG C (step 2)
A process for producing a polytetaconic acid crosslinked polymer according to any one of claims 1 to 3. 9. The method of claim 8, wherein the basic material is selected from the group consisting of sodium hydroxide, ammonia, calcium hydroxide, and sodium bicarbonate.
The method of claim 8, wherein the initiator is selected from the group consisting of Na ₂ S ₂ O ₅ , sodium persulfate (Na ₂ S ₂ O ₈ ), potassium persulfate (K ₂ S ₂ O ₈ ) Azobis (2-amidinopropane) dihydrochloride, 2,2-azobis- (N, N-dimethylene) isobutyraldehyde dihydrochloride (2, Azobis- (N, N-dimethylene) isobutyramidine dihydrochloride, 2- (carbamoylazo) isobutylonitrile, 2, 2-azobis [2- Azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride), 2,2'-azobisisobutyronitrile and 4,4-azo (4-azobis- (4-cyanovaleric acid)). &Lt; / RTI &gt;
An absorbent composition comprising a polytetaconic acid crosslinked polymer produced by the production method according to claim 8.
An absorbent composition comprising a polytetaconic acid crosslinked polymer produced by the production method according to claim 4.
An absorbent (water-absorbing) article comprising a sheet layer comprising a polytetaconic acid crosslinked polymer according to any one of claims 1 to 3.
The absorbent article according to claim 13, characterized in that it is a sanitary article, a diaper, a sanitary article, a garden soil repair agent, a civil or architectural index material, a seedling sheet, a food freshness preservative or a sachet.

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