KR20120075746A - Hydroxyalkyl carboxyalkyl starch and method for manufacturing the same - Google Patents

Abstract

PURPOSE: A manufacturing method of hydroxyalkyl carboxyalkyl starch is provided to improve productivity, to reduce cost, and to secure work safety by improving physical property of hydroxyalkyl carboxyalkyl starch. CONSTITUTION: A manufacturing method of hydroxyalkyl carboxyalkyl starch comprises: a step of forming gelatinized starch solution by putting starch suspension into the alkali solution comprising an alkali catalyst gelatinization process; a step of reacting etherification reaction by adding carboxy alkylating agent, and hydroxyalkylating agent; and a step of conducting a cross-linking reaction by adding a crosslinking agent into the mixture. The alkali catalyst comprises one or more selected from a group consisting of sodium hydroxide, potassium hydroxide, and calcium hydroxide.

Description

Hydroxyalkyl carboxyalkyl starch and its manufacturing method {HYDROXYALKYL CARBOXYALKYL STARCH AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to hydroxyalkyl carboxyalkyl starch and a method for preparing the same, and more particularly, to a method for producing hydroxyalkyl carboxyalkyl starch which can improve productivity, cost reduction, and work safety while improving physical properties. It relates to hydroxyalkyl carboxyalkyl starch prepared by.

Highly substituted ether starch is widely used as industrial material as sizing agent in textile industry, coating agent in paper industry, thickening binder or adhesive material in building material. Methods for preparing such highly substituted ether starch include a wet process, a solvent process and a dry process.

In the starch-suspended wet process, when water is used as a solvent, excessive swelling and gelatinization of starch particles are aggravated by excessive addition of an alkali catalyst. Thus, salts such as NaCl are mixed. However, the starch suspension wet process has a limit in increasing the degree of substitution, and thus, it is not possible to produce highly substituted etherified starch. In addition, the use of excess salt to prevent starch gelatinization during the reaction causes problems such as an increase in COD of purified wastewater and an increase in hardly decomposable substances.

In the starch liquefied wet process, in order to reduce the viscosity during the reaction to reduce the stirring load, a caustic soda solution, which is a catalyst, is liquefied by adding a low concentration of starch diluted with a large amount of water, and propylene oxide is added to produce a highly substituted hydroxypropyl starch. have. However, the starch liquefied wet process is low in reaction efficiency, there are disadvantages in that a lot of by-products are generated during the reaction, and energy consumption is high during drying.

In the solvent process, high-substituted hydroxypropyl starch may be produced, but an expensive organic solvent must be used, and an expensive recovery facility for recovering and reusing the solvent after the reaction is required. As a result, initial capital investment and production costs increase.

In the dry process, highly substituted hydroxypropyl starch may be prepared by applying an appropriate catalyst to raw material starch having a water content of 20% or less. When the high concentration of NaOH is applied as a catalyst, there is a problem that gelatinization of the starch particles is generated. Thus, after diluting to a low concentration to prevent this, a method of controlling the appropriate moisture through a drying process is applied to remove the increased moisture. However, the additional equipment and costs due to additional processes are a factor.

In order to solve the above problems, the present invention provides a method for preparing hydroxyalkyl carboxyalkyl starch, which can improve productivity, cost reduction, and operation safety while improving physical properties.

The present invention provides hydroxyalkyl carboxyalkyl starch which is prepared by the above production process and can be used in thickeners for cement, gypsum mortar and plaster.

In the method for preparing hydroxyalkyl carboxyalkyl starch according to the embodiments of the present invention, adding a starch suspension to an alkaline solution containing an alkali catalyst and gelatinizing to form a starch gelatinous solution, the carboxyalkylating agent and hydroxy to the starch gelatinized liquid Carrying out the etherification reaction by adding an oxyalkylating agent, and carrying out the crosslinking reaction by adding a crosslinking agent to the mixture having undergone the etherification reaction.

The alkali catalyst may include one or more selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide. The alkaline solution may be maintained at 60 ~ 90 ℃. The starch may include one or more selected from the group consisting of corn starch, waxy corn starch, tapioca starch, or a mixture thereof, and the starch suspension may be separately added to the alkaline solution.

The carboxyalkylating agent may include at least one selected from the group consisting of sodium monochloro acetate, sodium dichloro acetate, sodium trichloro acetate, monochloro acetic acid, dichloro acetic acid, trichloro acetic acid. The hydroxyalkylating agent may include at least one selected from the group consisting of propylene oxide, ethylene oxide and butylene oxide.

The crosslinking agent may include at least one selected from the group consisting of epichlorohydrin, formaldehyde, phosphorus oxychloride, and sodium methetaphosphate.

The hydroxyalkyl may be selected from the group consisting of hydroxypropyl, hydroxyethyl, hydroxybutyl, and the carboxyalkyl may be selected from the group consisting of carboxymethyl, carboxyethyl and carboxybutyl.

The hydroxyalkyl carboxyalkyl starch production method may further include the step of drying the mixture undergoing the crosslinking reaction onto a film in a drum dryer. The hydroxyalkyl carboxyalkyl starch production method may further comprise powdering the dried film to a size of 20 to 80 mesh.

The hydroxyalkyl carboxyalkyl starch according to the embodiments of the present invention is a hydroxyalkyl carboxyalkyl starch prepared according to the above method, and can be used in thickeners for cement, gypsum mortar and plaster.

According to embodiments of the present invention, high concentration liquefaction is possible, and by applying a crosslinking agent immediately before drying with a rheology improving agent, it is possible to dramatically improve the film forming ability in drum drying. As a result, the yield is improved, the drying efficiency is increased, the energy saving effect and the thickening effect are excellent, and the viscosity can be increased. In addition, by dividing the alkylene oxide, the reaction efficiency can be increased, the reaction can be carried out at low pressure, and the reactor investment cost can be reduced. In addition, by adjusting the powder particle size, dispersibility and flowability are improved, so that entanglement resistance is good during storage, and water solubility may be improved.

Building mortar prepared using starch according to the embodiments of the present invention is very excellent in the initial adhesion and deflection resistance during tile plastering compared to the mortar prepared by using the starch prepared by the conventional dry process or solvent process There is little stickiness and it is soft, and there is slipperiness, and coating property is excellent.

Hereinafter, the present invention will be described in more detail with reference to the following examples. The objects, features and advantages of the present invention will be readily understood through the following examples. The invention is not limited to the embodiments described herein, but may be embodied in other forms. The embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and the spirit of the present invention may be sufficiently delivered to those skilled in the art. Therefore, the present invention should not be limited by the following examples.

In the method for preparing hydroxyalkyl carboxyalkyl starch according to the embodiments of the present invention, adding a starch suspension to an alkaline solution containing an alkali catalyst and gelatinizing to form a starch gelatinous solution, the carboxyalkylating agent and hydroxy to the starch gelatinized liquid Carrying out the etherification reaction by adding an oxyalkylating agent, and carrying out the crosslinking reaction by adding a crosslinking agent to the mixture having undergone the etherification reaction.

In the hydroxyalkyl carboxyalkyl starch, hydroxyalkyl may be selected from the group consisting of hydroxypropyl, hydroxyethyl, hydroxybutyl, and preferably hydroxypropyl. Carboxyalkyl may be selected from the group consisting of carboxymethyl, carboxyethyl and carboxybutyl, preferably carboxymethyl.

The hydroxyalkyl carboxyalkyl starch may be used for thickeners for cement, gypsum mortar and plaster.

Starch Sum  Forming steps

The alkali catalyst may include at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, and preferably sodium hydroxide.

The temperature of the alkaline solution may be maintained at 60 ~ 90 ℃. If the temperature is less than 60 ℃ due to insufficient gelatinization due to the slow gelatinization rate in contact with the starch suspension, there is a problem that can lead to a stirrer load increase due to a rapid viscosity rise, resulting in a non-uniform reaction in the subsequent etherification reaction If the temperature exceeds 90 ° C, hydrolysis of starch by alkali may cause a decrease in viscosity and browning.

The starch may be used, such as corn starch, waxy corn starch, potato starch, tapioca starch or starch mixed with two or more of these starches, preferably corn starch.

The starch suspension is divided into small portions to allow sufficient gelatinization of the alkaline solution. In addition, the starch suspension may be maintained at a concentration of 20 to 35%. When the concentration is less than 20%, the etherification reaction efficiency may be lowered, and when the concentration is higher than 35%, the progress of the operation according to the reaction stirrer load may be difficult due to the increase in the viscosity of the reactant.

Etherification  Reaction step

The carboxyalkylating agent may include at least one selected from the group consisting of sodium monochloro acetate, sodium dichloro acetate, sodium trichloro acetate, monochloro acetic acid, dichloro acetic acid, trichloro acetic acid, preferably sodium monochloro acetate have. The hydroxyalkylating agent is an alkylene oxide, and may include one or more selected from the group consisting of propylene oxide, ethylene oxide, butylene oxide, preferably propylene oxide.

A carboxyalkylating agent is added to the alkali catalyzed starch liquor under sealing, and the hydroxyalkylating agent is added in small portions at a pressure of 1 kg / cm 2 or less, and a highly substituted etherification reaction can proceed. Since the hydroxyalkylating agent is added at one time, the pressure and temperature during the reaction may rise rapidly, which may cause a risk of explosion. Therefore, the hydroxyalkylating agent is continuously divided and added to maintain the reaction pressure at 1 kg / cm 2 or less.

Crosslinking reaction step

The crosslinking agent has a function of a rheology improving agent, and may include one or more selected from the group consisting of epichlorohydrin, formaldehyde, phosphorus oxychloride, and sodium methacrylate, and preferably epichlorohydrinyl. Can be.

The amount of the crosslinking agent added may be 0.05 to 0.15 parts by weight based on 100 parts by weight of starch solids. If the addition amount is less than 0.05 parts by weight, the rheological improvement effect of the reaction solution is insignificant, and the drying efficiency and productivity may be lowered due to poor film formation in the drum dryer. If the amount is more than 0.15 parts by weight, the swelling is suppressed and the viscosity is lowered. When mortar is applied, the thickening effect may be reduced.

The method for preparing hydroxyalkyl carboxyalkyl starch may further include drying the crosslinked mixture onto a film in a drum dryer after the crosslinking reaction step. In addition, the hydroxyalkyl carboxyalkyl starch production method may further comprise the step of powdering the size of the film dried on the film in the drum dryer to 20 to 80 mesh. The particle size of the starch is preferably maintained at 20 to 80 mesh, more preferably 20 to 60 mesh. If the particle size is less than 20 mesh, the rate of viscosity expression may be slow, and if it is more than 80 mesh, dispersibility may be lowered.

< Example  >

Example  One

The 25% sodium hydroxide solution was warmed to 30 ° C., 40 ° C., 60 ° C. and 80 ° C., respectively, and a small amount of 20% by weight waxy corn starch (Samyang Genex) suspension was added in small portions to liquefy until homogeneous. After standing for 10 minutes for each temperature, and compared to the viscosity and gelatin liquid flow is shown in Table 1 below. The higher the temperature of the sodium hydroxide solution, the faster the gelatinization rate of the starch and the lower the viscosity. Generally, the fluidity of the gelatinous liquid was good at a viscosity of about 20,000 cps or less, and the temperature of the alkaline solution was 60 to 90 ° C. The browning phenomenon appeared at the temperature over 90 degreeC, and the viscosity rose rapidly below 60 degreeC, and the fluidity fell badly. Therefore, by elevating the alkali solution to an appropriate temperature during starch liquefaction with an alkali catalyst, the fluidity of the gelatinous liquid can be improved, and the starch concentration of the gelatinous liquid can be made higher than at normal temperature (30 ° C). Viscosity was measured at a rotational speed of 6 rpm on a Brookfield VISCOMETER and at each temperature in Table 1 on spindle 4.

Sodium hydroxide solution temperature (℃) Viscosity (cps) Luxury liquidity 25 60,000 One 40 38,000 2 60 21,000 4 80 15,000 5 90 10,500 5

* Liquidity liquidity evaluation method: 5-point method (5: very good, 4: good, 3: normal, 2: stiff, 1: very stiff)

Example  2

236 g of 25% sodium hydroxide solution was heated to 80 ° C., and 2,400 g of corn starch (Samyang Genex) suspension was continuously added at a flow rate of about 6-7 ml per minute to prepare a gelatinous liquid. 173 g of sodium monochloro acetate (99%, Deoksan Co., Ltd.) was dissolved in this gelatin solution under air tightness, and 260 g of propylene oxide (99%, Acros Co., Ltd.) was continuously dissolved at a flow rate of about 5 ml per minute at a reaction pressure of 1 kg / cm 2 or less. The reaction was carried out by adding each portion. After the reaction was completed, it was dried on a film in a drum dryer. The dried film was ground and separated to pass through a 60 mesh sieve. Thus hydroxyalkyl carboxyalkyl starch was prepared by a liquefied wet process.

Example  3 to 6

In the same manner as in Example 2, 0.05 wt.% Of epichlorohydrin (99%, Kanto Chemical Co., Ltd.) to 100 parts by weight of dry starch in a mixture in which the etherification reaction was carried out before drying in a drum dryer (Simon) Part, 0.1 part by weight, 0.15 part by weight and 0.20 part by weight were respectively added to proceed with the crosslinking reaction.

The viscosity and drum drying workability of the highly substituted ether starches prepared in Examples 3 to 6 are shown in Table 2 below. It can be seen that the addition of epichlorohydrin in the wet process increases the viscosity and improves the film forming ability during drum drying, thereby improving the thickening effect and drum drying efficiency. However, as in Example 6, the viscosity was lowered when the epichlorohydrin was added in excess. Viscosity was measured at 25 ° C. on spindle 4 with a rotation speed of 6 rpm on a Brookfield VISCOMETER.

Example Manufacturing Method Epichlorohydrin addition
(Weight part / starch weight) 5% solution viscosity
(cps) Drum Drying Workability Example 2 Liquefied Wet Process - 500 X Example 3 0.05 850 O Example 4 0.10 1,000 O Example 5 0.15 1,900 O Example 6 0.20 1,500 O

O: The film is formed on a sheet and dried well.

X: It is formed in a powder form and it does not dry well.

Example  7

In the same manner as in Example 1, the amount of epichlorohydrin is added 0.1 parts by weight to 100 parts by weight of starch dry weight to proceed the crosslinking reaction, dried in a drum dryer (Simon), pulverized, particles They were sifted into 10 mesh, 20 mesh, 40 mesh, 60 mesh, 80 mesh, 100 mesh sieve.

In Example 7, the water dispersibility and the viscosity expression of the samples prepared by changing the particle size were evaluated, and the results are shown in Table 3 below. The larger the particles, the better the water dispersibility, but the dispersibility was lowered due to the entanglement from 100 mesh, the slower the viscosity development was, the lower the entanglement was observed at the 100 mesh. In conclusion, the particle size was generally good in water dispersibility and viscous expression in the range of 20 ~ 80 mesh, especially in the range of 20 ~ 60 mesh.

Particle Size (Mesh, #) Water dispersibility Viscosity 10 very good slow 20 very good fast 40 very good fast 60 very good fast 80 good fast 100 Bad (entangled phenomenon) Slow (entangled)

< Comparative example  >

Comparative example  One

2,400 g of corn starch (Samyang Genex) was added to a cylindrical reactor equipped with a horizontal stirrer (Rödigesa), and 268 g of granular 98% caustic soda was added and mixed with gentle stirring at 37 to 38 ° C for 1 hour. . After the reactor was sealed and vacuumed, 840 g of vaporized propylene oxide was added to the reactor while maintaining 45 to 48 ° C., and the mixture was subjected to a hydroxyalkylation reaction. After the hydroxyalkylation reaction was completed, the reactor was opened, and 76 g of sodium triphosphate anhydride and 360 g of sodium chloride acetate were added thereto. After closing the reactor again, the carboxymethylation reaction was performed for 3 hours while maintaining 55 ~ 58 ℃. After the reaction was completed, the reaction product was cooled to 35 ° C. and neutralized. The neutralized reaction product was triturated and passed through 120 mesh. As such, hydroxyalkyl carboxyalkyl starch was prepared by a dry process.

Comparative example  2

Into a reactor equipped with a closed vertical stirrer (Global Lab Co., Ltd.), 2,400 g of corn starch (Samyang Genex Co.), 3,100 g of propylene oxide (99%, Acros Co., Ltd.) and 83 g of water were mixed and stirred, followed by 9.66 276 g of% caustic soda (Youngjin Chemical Co., Ltd.) solution was added while spraying and alkalized at room temperature for 1 hour while stirring. After the reaction temperature was 70 ℃, the reaction pressure was maintained at 2.5bar, the etherification reaction proceeded for 3 hours. After the reaction was completed, the reaction mixture was neutralized with 36 g of 85% formic acid. After excess propylene oxide was removed from the reaction product, it was dried, pulverized and passed through 60 mesh. As such, hydroxyalkyl carboxyalkyl starch was prepared by a solvent process.

< Test Example  >

Test Tile Cement Mortal  Produce

300 g of cement (Hanil Cement Co., Ltd.), 700 g of sand (No. 6 Co.), 3 g of thickener (HPMC: starch = 7: 3), 230 g of water were added to a 3-liter Hobart mixer. Stirred for 60 seconds to prepare a test mortar. The starch sample in the thickener was used starch of Example 4 prepared by the wet process, starch of Comparative Example 1 prepared by the dry process, starch of Comparative Example 2 prepared by the solvent process. HPMC (Samsung Fine Chemical Co., Ltd., hydroxypropyl methyl cellulose) has a viscosity of 40,000 cps at 2% concentration.

Test Tile Cement Mortal  Property evaluation

Cement mortar properties were prepared using the hydroxyalkyl carboxyalkyl starch prepared in Example 4, Comparative Example 1, Comparative Example 2 and the results are shown in Table 4 below. In the cement mortar characteristics evaluation, the mortar flow (flow) was measured using a mortar flow tester (Heungjin Precision), the flow value (flow value) was measured, tile initial adhesion (Open time) is EN 1346 (Adhesives for tile-Determination of Open Time) and tile deflection resistance were measured according to EN 1308 (Adhesives for tiles-Determination of Slip).

Starch Manufacturing Method Mortar flow (mm) Tile initial adhesion Tile deflection resistance Example 4 Wet process 146 ++++ ++++ Comparative Example 1 Dry process 148 ++ ++ Comparative Example 2 Solvent process 151 +++ +++

The more * +, the better the initial adhesion of the tile and the resistance to the deflection of the tile.

Referring to Table 4, the cement mortar containing the starch prepared by the wet process has a relatively high mortar viscosity, and the initial adhesion of the tile and the sag of the tile compared to the cement mortar containing the starch prepared by the dry process or the solvent process. The resistance was excellent. Therefore, it was shown that there is little stickiness of mortar at the time of tile attachment work, and it has softness and slidability, and the coating property is also good.

Hereinafter, specific embodiments of the present invention have been described. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

Claims (11)

Adding a starch suspension to an alkaline solution containing an alkali catalyst and gelatinizing to form a starch gelatinized liquid;
Carrying out an etherification reaction by adding a carboxyalkylating agent and a hydroxyalkylating agent to the starch liquor; And
A method for preparing hydroxyalkyl carboxyalkyl starch, comprising the step of performing a crosslinking reaction by adding a crosslinking agent to the mixture having undergone the etherification reaction. In claim 1,
The alkali catalyst is a method for producing hydroxyalkyl carboxyalkyl starch, characterized in that it comprises at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide. In claim 1,
The alkali solution is hydroxyalkyl carboxyalkyl production method characterized in that it is maintained at 60 ~ 90 ℃. In claim 1,
The starch comprises one or more selected from the group consisting of corn starch, waxy corn starch, tapioca starch or mixtures thereof,
The starch suspension is hydroxyalkyl carboxyalkyl starch production method, characterized in that divided into the alkaline solution. In claim 1,
The carboxyalkylating agent is a hydroxyalkyl carboxy, characterized in that the carboxyalkylating agent comprises at least one selected from the group consisting of monochloro sodium acetate, sodium dichloro acetate, trichloro acetate, monochloro acetic acid, dichloro acetic acid, trichloro acetic acid Method for preparing alkyl starch. In claim 1,
The hydroxyalkylating agent is a hydroxyalkyl carboxyalkyl starch production method characterized in that it comprises at least one selected from the group consisting of propylene oxide, ethylene oxide, butylene oxide. In claim 1,
Wherein said crosslinking agent comprises at least one selected from the group consisting of epichlorohydrin, formaldehyde, phosphorus oxychloride, and sodium bimethaphosphate. In claim 1,
The hydroxyalkyl is selected from the group consisting of hydroxypropyl, hydroxyethyl, hydroxybutyl,
The carboxyalkyl is hydroxyalkyl carboxyalkyl starch production method, characterized in that selected from the group consisting of carboxymethyl, carboxyethyl, carboxybutyl. In claim 1,
Method for producing a hydroxyalkyl carboxyalkyl starch further comprises the step of drying the mixture undergoes the crosslinking reaction on a film in a drum dryer. In claim 9,
Method for producing a hydroxyalkyl carboxyalkyl starch further comprises the step of powdering the dried film to a size of 20 to 80 mesh. A hydroxyalkyl carboxyalkyl starch prepared according to the process according to any one of claims 1 to 10, wherein the hydroxyalkyl carboxyalkyl starch is used in thickeners for cement, gypsum mortar and plaster.